WorldWideScience

Sample records for platinum hexafluoride reacts

  1. Efficient removal of sulfur hexafluoride (SF6) through reacting with recycled electroplating sludge.

    Science.gov (United States)

    Zhang, Jia; Zhou, Ji Zhi; Liu, Qiang; Qian, Guangren; Xu, Zhi Ping

    2013-06-18

    This paper reports that recycled electroplating sludge is able to efficiently remove greenhouse gas sulfur hexafluoride (SF6). The removal process involves various reactions of SF6 with the recycled sludge. Remarkably, the sludge completely removed SF6 at a capacity of 1.10 mmol/g (SF6/sludge) at 600 °C. More importantly, the evolved gases were SO2, SiF4, and a limited amount of HF, with no toxic SOF4, SO2F2, or SF4 being detected. These generated gases can be readily captured and removed by NaOH solution. The reacted solids were further found to be various metal fluorides, thus revealing that SF6 removal takes place by reacting with various metal oxides and silicate in the sludge. Moreover, the kinetic investigation revealed that the SF6 reaction with the sludge is a first-order chemically controlled process. This research thus demonstrates that the waste electroplating sludge can be potentially used as an effective removal agent for one of the notorious greenhouse gases, SF6.

  2. Oxidizing behavior of some platinum metal fluorides. [Xe complexes with Pt, Pd fluorides; Chlorine-2 oxidation by transition metal hexafluorides

    Energy Technology Data Exchange (ETDEWEB)

    Graham, L.

    1978-10-01

    The previously known compounds Xe/sub 2/F/sub 3//sup +/PtF/sub 6//sup -/, XeF/sup +/PtF/sub 6//sup -/ and XeF/sub 2/.2PtF/sub 4/(XePt/sub 2/F/sub 10/) were prepared by the interaction of XeF/sub 2/ with PtF/sub 4/. The new compounds XeF/sub 2/.PdF/sub 4/ and XeF/sub 2/.2PdF/sub 4/(XePd/sub 2/F/sub 10/) were produced by interaction of XeF/sub 2/ with either PdF/sub 4/ or Pd/sub 2/F/sub 6/. A weight loss-versus-time curve indicated the presence of 4:1, 3:1 and 2:1 XeF/sub 2//PdF/sub 4/ complexes. The thermal decomposition of XeFPtF/sub 6/ or XePd/sub 2/F/sub 10/ yields highly pure XeF/sub 4/. Thus the interaction of XeF/sub 2/ with platinum fluorides (PtF/sub 4/ or PtF/sub 5/) or palladium fluorides (Pd/sub 2/F/sub 6/ or PdF/sub 4/) provides for the conversion of XeF/sub 2/ to XeF/sub 4/. The compound XePd/sub 2/F/sub 10/ is a close structural relative of XePt/sub 2/F/sub 10/, and spectroscopic evidence suggests that both are salts of XeF/sup +/ and a polymeric (M/sub 2/F/sub 9/)/sub x//sup x-/ ion. A Xe:PtF/sub 6/ material of approximately 1:1 stoichiometry has been prepared and compared with XePdF/sub 6/(XeF/sub 2/.PdF/sub 4/). The interaction of chlorine with the third-series transition metal hexafluorides has been investigated. Gravimetric and tensimetric evidence indicate that the initial product of the Cl/sub 2/ plus IrF/sub 6/ reaction is a solid of composition Cl/sub 2/IrF/sub 6/. Vibrational spectroscopic and other evidence indicates that this solid yields a sequence of products, of which Cl/sub 3//sup +/IrF/sub 6//sup -/, Cl/sub 3//sup +/Ir/sub 2/F/sub 11//sup -/ and Ir/sub 4/F/sub 20/ have been identified, the last being the ultimate solid product of the room temperature decomposition of the adduct. A new chlorine fluoride generated in the room temperature decomposition of Cl/sub 2/IrF/sub 6/ has been tentatively formulated as Cl/sub 3/F from infrared evidence.

  3. Uranium hexafluoride handling. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-31

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

  4. Reacting to "Reacting"

    Science.gov (United States)

    Houle, Amanda

    2006-01-01

    This article describes the author's experiences as a student participating in a general education program called "Reacting to the Past," in which college students play elaborate games set at pivotal moments in the past, their roles informed by great texts. She found that the experience of reenacting pivotal historical moments produced an intensely…

  5. The triple point of sulfur hexafluoride

    Science.gov (United States)

    Rourke, P. M. C.

    2016-04-01

    A cryogenic fixed point cell has been filled with high purity (99.999%) sulfur hexafluoride (SF6) and measured in an adiabatic closed-cycle cryostat system. Temperature measurements of the SF6 melting curve were performed using a capsule-type standard platinum resistance thermometer (CSPRT) calibrated over the International Temperature Scale of 1990 (ITS-90) subrange from the triple point of equilibrium hydrogen to the triple point of water. The measured temperatures were corrected by 0.37 mK for the effects of thermometer self-heating, and the liquidus-point temperature estimated by extrapolation to melted fraction F  =  1 of a simple linear regression versus melted fraction F in the range F  =  0.53 to 0.84. Based on this measurement, the temperature of the triple point of sulfur hexafluoride is shown to be 223.555 23(49) K (k  =  1) on the ITS-90. This value is in excellent agreement with the best prior measurements reported in the literature, but with considerably smaller uncertainty. An analysis of the detailed uncertainty budget of this measurement suggests that if the triple point of sulfur hexafluoride were to be included as a defining fixed point of the next revision of the International Temperature Scale, it could do so with a total realization uncertainty of approximately 0.43 mK, slightly larger than the realization uncertainties of the defining fixed points of the ITS-90. Since the combined standard uncertainty of this SF6 triple point temperature determination is dominated by chemical impurity effects, further research exploring gas purification techniques and the influence of specific impurity species on the SF6 triple point temperature may bring the realization uncertainty of SF6 as a fixed point material into the range of the defining fixed points of the ITS-90.

  6. Uranium hexafluoride bibliography

    Energy Technology Data Exchange (ETDEWEB)

    Burnham, S.L.

    1988-01-01

    This bibliography is a compilation of reports written about the transportation, handling, safety, and processing of uranium hexafluoride. An on-line literature search was executed using the DOE Energy files and the Nuclear Science Abstracts file to identify pertinent reports. The DOE Energy files contain unclassified information that is processed at the Office of Scientific and Technical Information of the US Department of Energy. The reports selected from these files were published between 1974 and 1983. Nuclear Science Abstracts contains unclassified international nuclear science and technology literature published from 1948 to 1976. In addition, scientific and technical reports published by the US Atomic Energy Commission and the US Energy Research and Development Administration, as well as those published by other agencies, universities, and industrial and research organizations, are included in the Nuclear Science Abstracts file. An alphabetical listing of the acronyms used to denote the corporate sponsors follows the bibliography.

  7. 49 CFR 173.338 - Tungsten hexafluoride.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Tungsten hexafluoride. 173.338 Section 173.338... SHIPMENTS AND PACKAGINGS Gases; Preparation and Packaging § 173.338 Tungsten hexafluoride. (a) Tungsten... expansion test, must be condemned if removed from tungsten hexafluoride service. [ 74 FR 16143, Apr. 9,...

  8. Acute toxicity of uranium hexafluoride, uranyl fluoride and hydrogen fluoride

    Energy Technology Data Exchange (ETDEWEB)

    Just, R.A.

    1988-01-01

    Uranium hexafluoride (UF/sub 6/) released into the atmosphere will react rapidly with moisture in the air to form the hydrolysis products uranyl fluoride (UO/sub 2/F/sub 2/) and hydrogen fluoride (HF). Uranium compounds such as UF/sub 6/ and UO/sub 2/F/sub 2/ exhibit both chemical toxicity and radiological effects, while HF exhibits only chemical toxicity. This paper describes the development of a methodology for assessing the human health consequences of a known acute exposure to a mixture of UF/sub 6/, UO/sub 2/F/sub 2/, and HF. 4 refs., 2 figs., 5 tabs.

  9. Helium and Sulfur Hexafluoride in Musical Instruments

    Science.gov (United States)

    Forinash, Kyle; Dixon, Cory L.

    2014-01-01

    The effects of inhaled helium on the human voice were investigated in a recent article in "The Physics Teacher." As mentioned in that article, demonstrations of the effect are a popular classroom activity. If the number of YouTube videos is any indication, the effects of sulfur hexafluoride on the human voice are equally popular.…

  10. 31 CFR 540.318 - Uranium Hexafluoride (UF6).

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Uranium Hexafluoride (UF6). 540.318... OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.318 Uranium Hexafluoride (UF6). The term...

  11. 高纯六氟化钨制备工艺研究%Preparation Technology of High Purity Tungsten Hexafluoride

    Institute of Scientific and Technical Information of China (English)

    陈志刚; 陈财华; 冯振雷

    2014-01-01

    介绍了利用氟气与钨粉为原料制备高纯六氟化钨的工艺方法和设备体系。其过程是利用电解槽电解氟氢化钾制取氟气,并采用氟化钠吸附配合深冷工艺纯化氟气,净化后的氟气与固定床里的钨粉在一定温度条件下反应合成初级六氟化钨,通过低温冷凝回收,收集的初级六氟化钨经过固化后抽真空排轻等方法进行初步提纯,然后将初步提纯的产品蒸馏至填料式精馏塔内进行深度提纯,经过多步提纯后的成品六氟化钨纯度可达99.999%以上。%This paper introduces the processing and equipment system for high-purity tungsten hexafluoride using fluorine gas and tungsten powder as raw materials. Electrolytic cell is applied to prepare fluorine gas by electrolyzing the potassium bifluoride. Sodium fluoride adsorption with cryogenic mixture is used to purify the fluorine gas. Purified fluorine gas reacts with tungsten powder to synthesize the impure tungsten hexafluoride in the fixed bed reactor at a certain temperature. The impure tungsten hexafluoride is obtained by low-temperature condensation. Curing and vacuuming technologies are performed on impure tungsten hexafluoride use to remove the volatile impurity. Filler type distillation column is utilized to further purify by monitoring the distillation products intermittently to prevent unqualified products collection. The results show that the purity of tungsten hexafluoride reaches 99.999%.

  12. Helium and Sulfur Hexafluoride in Musical Instruments

    Science.gov (United States)

    Forinash, Kyle; Dixon, Cory L.

    2014-11-01

    The effects of inhaled helium on the human voice were investigated in a recent article in The Physics Teacher.1 As mentioned in that article, demonstrations of the effect are a popular classroom activity. If the number of YouTube videos is any indication, the effects of sulfur hexafluoride on the human voice are equally popular. However, there appears to be little information available on the effects of either of these gases on musical instruments.2 We describe here the results of a student project that involved measuring the frequency shifts in an organ pipe, a trumpet, and a trombone as the result of filling the instruments with these two gases. The project was one of several possible end-of-semester projects required in an elective science of sound course for non-science majors.

  13. Uranium hexafluoride purification; Purificacao de hexafluoreto de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Eneas F. de

    1986-07-01

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

  14. Platinum impact assessment

    OpenAIRE

    Yip, Joyce Pui Yan

    2007-01-01

    This paper presents a comprehensive strategic analysis of Company X's strategies to mitigate its risks from volatile platinum prices, since Platinum is a critical component of fuel cells. It is recommended that Company X consider leasing platinum to lower cash flow requirements to meet its platinum demand over the next 5 years. A shorter platinum leasing period will reduce Company X's platinum market risk. OEMs can set up metal accounts with catalyst suppliers to eliminate Company X from plat...

  15. Electron Ionization Mass Spectrum of Tellurium Hexafluoride

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Richard A.; McNamara, Bruce K.; Barinaga, Charles J.; Peterson, James M.; Govind, Niranjan; Andersen, Amity; Abrecht, David G.; Schwantes, Jon M.; Ballou, Nathan E.

    2015-05-18

    The first electron ionization mass spectrum of tellurium hexafluoride (TeF6) is reported. The starting material was produced by direct fluorination of Te metal or TeO2 with nitrogen trifluoride. Formation of TeF6 was confirmed through cryogenic capture of the tellurium fluorination product and analysis through Raman spectroscopy. The eight natural abundance isotopes were observed for each of the set of fragment ions: TeF5+, TeF4+ TeF3+, TeF2+, TeF1+, and Te+, Te2+. A trend in increasing abundance was observed for the even fluoride bearing ions: TeF1+ < TeF3+ < TeF5+, and a decreasing abundance was observed for the even fragment series: Te(0)+ > TeF2+ > TeF4+ > TeF6+, with the molecular ion TeF6+ not observed at all. Density functional theory based electronic structure calculations were used to calculate optimized ground state geometries of these gas phase species and their relative stabilities explain the trends in the data and the lack of observed signal for TeF6+.

  16. Fire testing of bare uranium hexafluoride cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Pryor, W.A. [PAI Corp., Oak Rige, TN (United States)

    1991-12-31

    In 1965, the Oak Ridge Gaseous Diffusion Plant (ORGDP), now the K-25 Site, conducted a series of tests in which bare cylinders of uranium hexafluoride (UF{sub 6}) were exposed to engulfing oil fires for the US Atomic Energy Commission (AEC), now the US Department of Energy (DOE). The tests are described and the results, conclusions, and observations are presented. Two each of the following types of cylinders were tested: 3.5-in.-diam {times} 7.5-in.-long cylinders of Monel (Harshaw), 5.0-in.-diam {times} 30-in.-long cylinders of Monel, and 8-in.-diam {times} 48-in.-long cylinders of nickel. The cylinders were filled approximately to the standard UF{sub 6} fill limits of 5, 55, and 250 lb, respectively, with a U-235 content of 0.22%. The 5-in.- and 8-in.-diam cylinders were tested individually with and without their metal valve covers. For the 3.5-in.-diam Harshaw cylinders and the 5.0-in.-diam cylinder without a valve cover the valves failed and UF{sub 6} was released. The remaining cylinders ruptured explosively in time intervals ranging from about 8.5 to 11 min.

  17. Fire testing of bare uranium hexafluoride cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Pryor, W.A. [PAI Corp., Oak Ridge, TN (United States)

    1991-12-31

    In 1965, the Oak Ridge Gaseous Diffusion Plant (ORGDP), now the K-25 Site, conducted a series of tests in which bare cylinders of uranium hexafluoride (UF{sub 6}) were exposed to engulfing oil fires for the US Atomic Energy Commission (AEC), now the US Department of Energy (DOE). The tests are described and the results, conclusions, and observations are presented. Two each of the following types of cylinders were tested: 3.5-in.-diam {times} 7.5-in.-long cylinders of Monel (Harshaw), 5.0-in.-diam {times} x 30-in.-long cylinders of Monel, and 8-in.-diam {times} 48-in.-long cylinders of nickel. The cylinders were filled approximately to the standard UF{sub 6} fill limits of 5, 55, and 250 lb, respectively, with a U-235 content of 0.22%. The 5-in.- and 8-in.-diam cylinders were tested individually with and without their metal valve covers. For the 3.5-in.-diam Harshaw cylinders and the 5.0-in.-diam cylinder without a valve cover, the valves failed and UF{sub 6} was released. The remaining 6 cylinders ruptured explosively in time intervals ranging from about 8.5 to 11 min.

  18. Electron ionization mass spectrum of tellurium hexafluoride.

    Science.gov (United States)

    Clark, Richard A; McNamara, Bruce K; Barinaga, Charles J; Peterson, James M; Govind, Niranjan; Andersen, Amity; Abrecht, David G; Schwantes, Jon M; Ballou, Nathan E

    2015-05-18

    The electron ionization mass spectrum of tellurium hexafluoride (TeF6) is reported for the first time. The starting material was produced by direct fluorination of Te metal or TeO2 with nitrogen trifluoride. Formation of TeF6 was confirmed through cryogenic capture of the tellurium fluorination product and analysis through Raman spectroscopy. The eight natural abundance isotopes were observed for each of the set of fragment ions: TeF5(+), TeF4(+) TeF3(+), TeF2(+), TeF1(+), and Te(+), Te2(+). A trend in increasing abundance was observed for the odd fluoride bearing ions, TeF1(+) TeF2(+) > TeF4(+) > TeF6(+), with the molecular ion TeF6(+) not observed at all. Density functional theory based electronic structure calculations were used to calculate optimized ground state geometries of these gas phase species, and their relative stabilities explain the trends in the data and the lack of observed signal for TeF6(+).

  19. The REACT Project

    DEFF Research Database (Denmark)

    Bloch, Paul; Blystad, Astrid; Byskov, Jens;

    selected disease and programme interventions and services, within general care and on health systems management. Efforts to improve health sector performance have not yet been satisfactory, and adequate and sustainable improvements in health outcomes have not been shown. Priority setting in health systems...... decisions; and the provision of leadership and the enforcement of conditions. REACT - "REsponse to ACcountable priority setting for Trust in health systems" is an EU-funded five-year intervention study, which started in 2006 testing the application and effects of the AFR approach in one district each...... in Kenya, Tanzania and Zambia. Qualitative and quantitative methods are applied in an action research framework. The project baseline surveys have already been completed and indicate both a strong need and a high willingness for change in the study districts. REACT has developed active research...

  20. 49 CFR 173.420 - Uranium hexafluoride (fissile, fissile excepted and non-fissile).

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Uranium hexafluoride (fissile, fissile excepted....420 Uranium hexafluoride (fissile, fissile excepted and non-fissile). (a) In addition to any other... non-fissile uranium hexafluoride must be offered for transportation as follows: (1) Before...

  1. Study on the enrichment of Sulfur Hexafluoride in the tmosphere through polyimide hollow fiber membrane

    Directory of Open Access Journals (Sweden)

    Wang Weixian

    2016-01-01

    Full Text Available Sulfur hexafluoride is per molecule the strongest greenhouse gas know, the features have brought SF6 into the climatic impact discussion aimed at reduction of emissions. The separation effects of sulfur hexafluoride in the atmosphere are studied through polyimide hollow fiber membrane with different conditions on pressure drop, gas flow and temperature. The sulfur hexafluoride concentration increased with increased pressure drop of the membrane, increased temperature and decreased non-filtrate flow flux; the recovery of sulfur hexafluoride exceeds 93%, enrichment coefficient was 18.5; sulfur hexafluoride is not detected at the flux of the filtrate flow, which means sulfur hexafluoride is riddled by membrane. The results showed that polyimide hollow fiber membrane can effectively separate sulfur hexafluoride from mixed gas

  2. Highly trifluoromethylated platinum compounds.

    Science.gov (United States)

    Martínez-Salvador, Sonia; Forniés, Juan; Martín, Antonio; Menjón, Babil

    2011-07-11

    The homoleptic, square-planar organoplatinum(II) compound [NBu(4)](2) [Pt(CF(3))(4)] (1) undergoes oxidative addition of CF(3) I under mild conditions to give rise to the octahedral organoplatinum(IV) complex [NBu(4)](2) [Pt(CF(3))(5)I] (2). This highly trifluoromethylated species reacts with Ag(+) salts of weakly coordinating anions in Me(2)CO under a wet-air stream to afford the aquo derivative [NBu(4)][Pt(CF(3))(5) (OH(2))] (4) in around 75% yield. When the reaction of 2 with the same Ag(+) salts is carried out in MeCN, the solvento compound [NBu(4) ][Pt(CF(3))(5)(NCMe)] (5) is obtained in around 80% yield. The aquo ligand in 4 as well as the MeCN ligand in 5 are labile and can be cleanly replaced by neutral and anionic ligands to furnish a series of pentakis(trifluoromethyl)platinate(IV) compounds with formulae [NBu(4)][Pt(CF(3))(5) (L)] (L=CO (6), pyridine (py; 7), tetrahydrothiophene (tht; 8)) and [NBu(4)](2) [Pt(CF(3))(5)X] (X=Cl (9), Br (10)). The unusual carbonyl-platinum(IV) derivative [NBu(4)][Pt(CF(3))(5) (CO)] (6) is thermally stable and has a ν(CO) of 2194 cm(-1). The crystal structures of 2⋅CH(2)Cl(2), 5, [PPh(4) ][Pt(CF(3))(5)(CO)] (6'), and 7 have been established by X-ray diffraction methods. Compound 2 has shown itself to be a convenient entry to the chemistry of highly trifluoromethylated platinum compounds. To the best of our knowledge, compounds 2 and 4-10 are the organoelement compounds with the highest CF(3) content to have been isolated and adequately characterized to date.

  3. PLATINUM AND FUEL CELLS

    Science.gov (United States)

    Platinum requirements for fuel cell vehicles (FCVS) have been identified as a concern and possible problem with FCV market penetration. Platinum is a necessary component of the electrodes of fuel cell engines that power the vehicles. The platinum is deposited on porous electrodes...

  4. Sulphur hexafluoride as a stripper gas for tandem accelerators

    Science.gov (United States)

    Hotchkis, M. A. C.; Child, D.; Fink, D.; Garton, D.; Levchenko, V.; Wilcken, K.

    2013-05-01

    We have investigated sulphur hexafluoride as a stripper gas in tandem accelerators by using the ANTARES accelerator system at ANSTO to measure charge state distributions for this gas. Results are reported at 4 MV terminal voltage for injected negative ions ranging from carbon to uranium oxide. For iodine and thorium the distributions are extended across a range of energies of practical use for accelerator mass spectrometry, ion beam analysis and other accelerator applications. Charge state distributions using sulphur hexafluoride are found to have mean charge states up to 1 charge unit higher than, and to be broader than, corresponding distributions for argon gas, except in the case of carbon beams. As a result, SF6 is shown to provide significantly higher yields for charge states of heavy ions above the mean charge state. We now perform actinide AMS measurements with 9% yield to the 5+ charge state, compared to 4-5% achieved previously with argon gas.

  5. Chemistry of the 5g Elements: Relativistic Calculations on Hexafluorides.

    Science.gov (United States)

    Dognon, Jean-Pierre; Pyykkö, Pekka

    2017-08-14

    A Periodic System was proposed for the elements 1-172 by Pyykkö on the basis of atomic and ionic calculations. In it, the elements 121-138 were nominally assigned to a 5g row. We now perform molecular, relativistic four-component DFT calculations and find that the hexafluorides of the elements 125-129 indeed enjoy occupied 5g states. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Sulphur hexafluoride as a stripper gas for tandem accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Hotchkis, M.A.C., E-mail: mah@ansto.gov.au; Child, D.; Fink, D.; Garton, D.; Levchenko, V.; Wilcken, K.

    2013-05-01

    Highlights: •Sulphur hexafluoride is investigated as a stripper gas in tandem accelerators. •For heavy ions at low terminal voltage, mean charge states are found to be up to 1 charge unit higher than with argon gas. •Charge state distributions are found to be broader than with argon gas. •For charge states above the mean charge state, yields are typically doubled using SF{sub 6}. •Using SF{sub 6} stripper gas, the efficiency of actinides AMS analysis is doubled. -- Abstract: We have investigated sulphur hexafluoride as a stripper gas in tandem accelerators by using the ANTARES accelerator system at ANSTO to measure charge state distributions for this gas. Results are reported at 4 MV terminal voltage for injected negative ions ranging from carbon to uranium oxide. For iodine and thorium the distributions are extended across a range of energies of practical use for accelerator mass spectrometry, ion beam analysis and other accelerator applications. Charge state distributions using sulphur hexafluoride are found to have mean charge states up to 1 charge unit higher than, and to be broader than, corresponding distributions for argon gas, except in the case of carbon beams. As a result, SF{sub 6} is shown to provide significantly higher yields for charge states of heavy ions above the mean charge state. We now perform actinide AMS measurements with 9% yield to the 5+ charge state, compared to 4–5% achieved previously with argon gas.

  7. TRANSITION STATE FOR THE GAS-PHASE REACTION OF URANIUM HEXAFLUORIDE WITH WATER

    Energy Technology Data Exchange (ETDEWEB)

    Garrison, S; James Becnel, J

    2008-03-18

    Density Functional Theory and small-core, relativistic pseudopotentials were used to look for symmetric and asymmetric transitions states of the gas-phase hydrolysis reaction of uranium hexafluoride, UF{sub 6}, with water. At the B3LYP/6-31G(d,p)/SDD level, an asymmetric transition state leading to the formation of a uranium hydroxyl fluoride, U(OH)F{sub 5}, and hydrogen fluoride was found with an energy barrier of +77.3 kJ/mol and an enthalpy of reaction of +63.0 kJ/mol (both including zero-point energy corrections). Addition of diffuse functions to all atoms except uranium led to only minor changes in the structure and relative energies of the reacting complex and transition state. However, a significant change in the product complex structure was found, significantly reducing the enthalpy of reaction to +31.9 kJ/mol. Similar structures and values were found for PBE0 and MP2 calculations with this larger basis set, supporting the B3LYP results. No symmetric transition state leading to the direct formation of uranium oxide tetrafluoride, UOF{sub 4}, was found, indicating that the reaction under ambient conditions likely includes several more steps than the mechanisms commonly mentioned. The transition state presented here appears to be the first published transition state for the important gas-phase reaction of UF{sub 6} with water.

  8. Uranium hexafluoride: Safe handling, processing, and transporting: Conference proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Strunk, W.D.; Thornton, S.G. (eds.)

    1988-01-01

    This conference seeks to provide a forum for the exchange of information and ideas of the safety aspects and technical issue related to the handling of uranium hexafluoride. By allowing operators, engineers, scientists, managers, educators, and others to meet and share experiences of mutual concern, the conference is also intended to provide the participants with a more complete knowledge of technical and operational issues. The topics for the papers in the proceedings are widely varied and include the results of chemical, metallurgical, mechanical, thermal, and analytical investigations, as well as the developed philosophies of operational, managerial, and regulatory guidelines. Papers have been entered individually into EDB and ERA. (LTN)

  9. Behind platinum's sparkle.

    Science.gov (United States)

    Yam, Vivian W W

    2010-09-01

    As a rare and precious metal that is also resistant to wear and tarnish, platinum is known to be particularly well-suited to jewellery. Vivian Yam reflects on how, beyond its prestigious image, platinum has also found its way into a variety of fields ranging from the petrochemical to the pharmaceutical industry.

  10. Photoreductive degradation of sulfur hexafluoride in the presence of styrene

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Sulfur hexafluoride (SF6) is known as one of the most powerful greenhouse gases in the atmosphere. Reductive photodegradation of SM6 by styrene has been studied with the purpose of developing a novel remediation for sulfur hexafluoride pollution. Effects of reaction conditions on the destruction and removal efficiency (DRE) of SF6 are examined in this study. Both initial styrene-to-SF6 ratio and initial oxygen concentration exert a significant influence on DRE. SF6 removal efficiency reaches a maximum value at the initial styrene-to-SF6 ratio of 0.2. It is found that DRE increases with oxygen concentration over the range of 0 to 0.09 mol/m3 and then decreases with increasing oxygen concentration. When water vapor is fed into the gas mixture, DRE is slightly enhanced over the whole studied time scale. The X-ray Photoelectron Spectroscopy (XPS) analysis, together with gas chromatography-mass spectrometry (GC-MS) and Fourier Transform Infrared spectroscopy (FT-IR) analysis, prove that nearly all the initial fluorine residing in the gas phase is in the form of SiF4, whereas, the initial sulfur is deposited in the form of elemental sulfur, after photodegradation. Free from toxic byproducts, photodegradation in the presence of styrene may serve as a promising technique for SF6 abatement.

  11. Design and calibration of the AWCC for measuring uranium hexafluoride

    Energy Technology Data Exchange (ETDEWEB)

    Wenz, T.R.; Menlove, H.O.; WSalton, G.; Baca, J.

    1995-08-01

    An Active Well Coincidence Counter (AWCC) has been modified to measure variable enrichment uranium hexafluoride (UF{sub 6}) in storage bottles. An active assay technique was used to measure the {sup 235}U content because of the small quantity (nominal loading of 2 kg UF{sub 6}) and nonuniform distribution of UF{sub 6} in the storage bottles. A new insert was designed for the AWCC composed of graphite containing four americium-lithium sources. Monte Carlo calculations were used to design the insert and to calibrate the detector. Benchmark measurements and calculations were performed using uranium oxide resulted in assay values that agreed within 2 to 3% of destructive assay values. In addition to UF{sub 6}, the detector was also calibrated for HEU ingots, billets, and alloy scrap using the standard Mode 1 end-plug configuration.

  12. Selection of a management strategy for depleted uranium hexafluoride

    Energy Technology Data Exchange (ETDEWEB)

    Patton, S.E.; Hanrahan, E.J.; Bradley, C.E.

    1995-09-06

    A consequence of the uranium enrichment process used in the United States (US) is the accumulation of a significant amount of depleted uranium hexafluoride (UF{sub 6}). Currently, approximately 560,000 metric tons of the material are stored at three different sites. The US Department of Energy (DOE) has recently initiated a program to consider alternative strategies for the cost-effective and environmentally safe long-term management of this inventory of depleted UF{sub 6}. The program involves a technology and engineering assessment of proposed management options (use/reuse, conversion, storage, or disposal) and an analysis of the potential environmental impacts and life-cycle costs of alternative management strategies. The information obtained from the studies will be used by the DOE to select a preferred long-term management strategy. The selection and implementation of a management strategy will involve consideration of a number of important issues such as environmental, health, and safety effects; the balancing of risks versus costs in a context of reduced government spending; socioeconomic implications, including effects on the domestic and international uranium industry; the technical status of proposed uses or technologies; and public involvement in the decision making process. Because of its provisions for considering a wide range of relevant issues and involving the public, this program has become a model for future DOE materials disposition programs. This paper presents an overview of the Depleted Uranium Hexafluoride Management Program. Technical findings of the program to date are presented, and major issues involved in selecting and implementing a management strategy are discussed.

  13. Depleted uranium hexafluoride: The source material for advanced shielding systems

    Energy Technology Data Exchange (ETDEWEB)

    Quapp, W.J.; Lessing, P.A. [Idaho National Engineering Lab., Idaho Falls, ID (United States); Cooley, C.R. [Department of Technology, Germantown, MD (United States)

    1997-02-01

    The U.S. Department of Energy (DOE) has a management challenge and financial liability problem in the form of 50,000 cylinders containing 555,000 metric tons of depleted uranium hexafluoride (UF{sub 6}) that are stored at the gaseous diffusion plants. DOE is evaluating several options for the disposition of this UF{sub 6}, including continued storage, disposal, and recycle into a product. Based on studies conducted to date, the most feasible recycle option for the depleted uranium is shielding in low-level waste, spent nuclear fuel, or vitrified high-level waste containers. Estimates for the cost of disposal, using existing technologies, range between $3.8 and $11.3 billion depending on factors such as the disposal site and the applicability of the Resource Conservation and Recovery Act (RCRA). Advanced technologies can reduce these costs, but UF{sub 6} disposal still represents large future costs. This paper describes an application for depleted uranium in which depleted uranium hexafluoride is converted into an oxide and then into a heavy aggregate. The heavy uranium aggregate is combined with conventional concrete materials to form an ultra high density concrete, DUCRETE, weighing more than 400 lb/ft{sup 3}. DUCRETE can be used as shielding in spent nuclear fuel/high-level waste casks at a cost comparable to the lower of the disposal cost estimates. Consequently, the case can be made that DUCRETE shielded casks are an alternative to disposal. In this case, a beneficial long term solution is attained for much less than the combined cost of independently providing shielded casks and disposing of the depleted uranium. Furthermore, if disposal is avoided, the political problems associated with selection of a disposal location are also avoided. Other studies have also shown cost benefits for low level waste shielded disposal containers.

  14. Platinum hypersensitivity and desensitization.

    Science.gov (United States)

    Miyamoto, Shingo; Okada, Rika; Ando, Kazumichi

    2015-09-01

    Platinum agents are drugs used for various types of cancer. With increased frequency of administration of platinum agents, hypersensitivity reactions appear more frequently, occurring in over 25% of cases from the seventh cycle or second line onward. It then becomes difficult to conduct treatment using these agents. Various approaches have been investigated to address hypersensitivity reactions to platinum agents. Desensitization, which gradually increases the concentration of the anticancer drug considered to be the antigen until the target dosage, has been reported as being particularly effective, with a success rate of 80-100%. The aims of this paper are to present the current findings regarding hypersensitivity reactions to platinum agents and to discuss attempts of using desensitization against hypersensitivity reactions worldwide. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. Decomposition of potent greenhouse gas sulfur hexafluoride (SF6) by Kirschsteinite-dominant stainless steel slag.

    Science.gov (United States)

    Zhang, Jia; Zhou, Ji Zhi; Xu, Zhi Ping; Li, Yajun; Cao, Tiehua; Zhao, Jun; Ruan, Xiuxiu; Liu, Qiang; Qian, Guangren

    2014-01-01

    In this investigation, kirschsteinite-dominant stainless steel slag (SSS) has been found to decompose sulfur hexafluoride (SF6) with the activity higher than pure metal oxides, such as Fe2O3 and CaO. SSS is mainly made up of CaO·FeO·SiO2(CFS)/MgO·FeO·MnO(RO) phase conglomeration. The SF6 decomposition reaction with SSS at 500-700 °C generated solid MF2/MF3 and gaseous SiF4, SO2/SO3 as well as HF. When 10 wt % of SSS was replaced by Fe2O3 or CaO, the SF6 decomposition amount decreased from 21.0 to 15.2 or 15.0 mg/g at 600 °C. The advantage of SSS over Fe2O3 or CaO in the SF6 decomposition is related to its own special microstructure and composition. The dispersion of each oxide component in SSS reduces the sintering of freshly formed MF2/MF3, which is severe in the case of pure metal oxides and inhibits the continuous reaction of inner components. Moreover, SiO2 in SSS reacts with SF6 and evolves as gaseous SiF4, which leaves SSS with voids and consequently exposes inner oxides for further reactions. In addition, we have found that oxygen significantly inhibited the SF6 decomposition with SSS while H2O did not, which could be explained in terms of reaction pathways. This research thus demonstrates that waste material SSS could be potentially an effective removal reagent of greenhouse gas SF6.

  16. Heterogeneous platinum-catalyzed hydrogenation of dialkyl(diolefin)platinum(II) complexes: A new route to platinum surface alkyls

    OpenAIRE

    McCarthy, Thomas J.; Shih, Yen-Shiang; Whitesides, George M.

    1981-01-01

    Platinum metal catalyzes the reduction of dialkyl(diolefin)platinum(II) complexes by dihydrogen to alkanes and platinum(0). The reaction involves adsorption of the platinum(II) complex on the platinum(0) catalyst surface with conversion of the alkyl moieties to platinum surface alkyls; these appear as alkane products. The platinum atom originally present in the soluble organoplatinum species becomes part of the platinum(0) surface.

  17. SYNTHESIS OF POLYSILOXANE-SUPPORTED SELENAETHER PLATINUM COMPLEX AND ITS CATALYTIC PROPERTY FOR HYDROSILYLATION OF OLEFINS

    Institute of Scientific and Technical Information of China (English)

    LU Xueran; CHEN Zhen; DUAN Heping; CHEN Yifan

    1996-01-01

    A new type of selenious polymer, silica-bound polybispropoxyethyl-selenidesilsesquioxane,and its platinum complex were synthesized from bis-allyloxyethyl selenide via hydrosilylation with triethoxysilane, followed by immobilized on fumed silica, and then reacting with potassium chloroplatinite under nitrogen atmosphere in acetone. It was found that the platinum complex can catalyze the hydrosilylation of olefins with triethoxysilane effectively. The effects of the nature of the substrate, the amount of complex used, and the reaction temperature on the catalytic activity were investigated.

  18. Toxicity of platinum compounds.

    Science.gov (United States)

    Hartmann, Jörg Thomas; Lipp, Hans-Peter

    2003-06-01

    Since the introduction of platinum-based combination chemotherapy, particularly cisplatin, the outcome of the treatment of many solid tumours has changed. The leading platinum compounds in cancer chemotherapy are cisplatin, carboplatin and oxaliplatin. They share some structural similarities; however, there are marked differences between them in therapeutic use, pharmacokinetics and adverse effects profiles [1-4]. Compared to cisplatin, carboplatin has inferior efficacy in germ-cell tumour, head and neck cancer and bladder and oesophageal carcinoma, whereas both drugs seem to have comparable efficacy in advanced non-small cell and small cell lung cancer as well as ovarian cancer [5-7]. Oxaliplatin belongs to the group of diaminocyclohexane platinum compounds. It is the first platinum-based drug that has marked efficacy in colorectal cancer when given in combination with 5-fluorouracil and folinic acid [8,9]. Other platinum compounds such as oral JM216, ZD0473, BBR3464 and SPI-77, which is a pegylated liposomal formulation of cisplatin, are still under investigation [10-13], whereas nedaplatin has been approved in Japan for the treatment of non-small cell lung cancer and other solid tumours. This review focuses on cisplatin, carboplatin and oxaliplatin.

  19. Oxygen Reduction on Platinum

    DEFF Research Database (Denmark)

    Nesselberger, Markus

    This thesis investigates the electro reduction of oxygen on platinum nanoparticles, which serve as catalyst in low temperature fuel cells. Kinetic studies on model catalysts as well as commercially used systems are presented in order to investigate the particle size effect, the particle proximity...... carbon (HSAC) supported Pt nanoparticle (Pt/C) catalysts (of various size between 1 and 5 nm). The difference in SA between the individual Pt/C catalysts (1 to 5 nm) is very small and within the error of the measurements. The factor four of loss in SA when comparing platinum bulk and Pt/C can largely...

  20. Optimized molecular force field for sulfur hexafluoride simulations.

    Science.gov (United States)

    Olivet, Aurelio; Vega, Lourdes F

    2007-04-14

    An optimized molecular force field for sulfur hexafluoride (SF6) simulations is presented in this work. The new force field for SF6 contains two parts: a Lennard-Jones potential that deals with F-F intermolecular interactions and the second term dealing with the intramolecular forces. In this second part the flexibility of the molecule is explicitly considered by 6 harmonic stretch terms, modeling the S-F chemical bonds, and 12 harmonic bending terms, modeling the F-S-F angular deformations. The parameters of the new force field have been obtained by a multivariable optimization procedure, whose main feature is the simultaneous fitting of all force field parameters, using as reference data several equilibrium properties (vapor pressure, saturated liquid density, and surface tension) and shear viscosity. The new force field clearly improves the description of the phase envelope and the rest of the properties as compared to previous simulations for a rigid model for the same molecule [A. Olivet et al., J. Chem. Phys. 123, 194508 (2005)]. Results for the optimized force field concerning the vapor-liquid coexistence curve, several thermodynamics states at the homogeneous gas and liquid region, and transport coefficients of SF6 are in good agreement with available experimental data.

  1. Standard test methods for arsenic in uranium hexafluoride

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 These test methods are applicable to the determination of total arsenic in uranium hexafluoride (UF6) by atomic absorption spectrometry. Two test methods are given: Test Method A—Arsine Generation-Atomic Absorption (Sections 5-10), and Test Method B—Graphite Furnace Atomic Absorption (Appendix X1). 1.2 The test methods are equivalent. The limit of detection for each test method is 0.1 μg As/g U when using a sample containing 0.5 to 1.0 g U. Test Method B does not have the complete collection details for precision and bias data thus the method appears as an appendix. 1.3 Test Method A covers the measurement of arsenic in uranyl fluoride (UO2F2) solutions by converting arsenic to arsine and measuring the arsine vapor by flame atomic absorption spectrometry. 1.4 Test Method B utilizes a solvent extraction to remove the uranium from the UO2F2 solution prior to measurement of the arsenic by graphite furnace atomic absorption spectrometry. 1.5 Both insoluble and soluble arsenic are measured when UF6 is...

  2. Biomineralization of platinum by microorganisms

    Science.gov (United States)

    Pavlova, L. M.; Radomskaya, V. I.; Shumilova, L. P.; Ionov, A. M.; Sorokin, P.

    2017-04-01

    The mechanism of platinum biomineralization by microscopic fungi is displayed based on data of electron microscopy, infrared and X-ray photoelectronic spectroscopy. It was suggested the platinum sorption process by microscopic fungi has some stages. The initial interaction is carried out by the mechanisms of physical and chemical sorption. Hereafter the reduction process of adsorbed platinum ions up to zero state is performed, probably, for account of organic compounds, which are produced by fungi biomass as metabolism result, and the process terminates by nulvalent particles aggregating up to nanosize forms. Obtained data on the platinum biomineralization extends the concept concerning the character of forming platinum nanoparticles in carbonous paleobasin.

  3. Platinum metals in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Zereini, Fathi [Frankfurt Univ. (Germany). Dept. of Environmental Analytical Chemistry; Wiseman, Clare L.S. (ed.) [Toronto Univ. (Canada). School of the Environment

    2015-03-01

    This book contains the five chapters with the following topics: 1. SOURCES OF PGE EMISSIONS ELEMENTS: Sources of Platinum Group Elements (PGE) in the Environment; Impact of Platinum Group Element Emissions from Mining and Production Activities. 2. ANALYTICAL METHODS FOR THE DETERMINATION OF PGE IN BIOLOGICAL AND ENVIRONMENTAL MATRICES: Appraisal of Biosorption for Recovery, Separation and Determination of Platinum, Palladium and Rhodium in Environmental Samples; On the Underestimated Factors Influencing the Accuracy of Determination of Pt and Pd by Electrothermal Atomic Absorption Spectrometry in Road Dust Samples; Application of Solid Sorbents for Enrichment and Separation of Platinum Metal Ions; Voltammetric Analysis of Platinum in Environmental Matrices; Speciation Analysis of Chloroplatinates; Analysis of Platinum Group Elements in Environmental Samples: A Review. 3. OCCURRENCE, CHEMICAL BEHAVIOR AND FATE OF PGE IN THE ENVIRONMENT: Brazilian PGE Research Data Survey on Urban and Roadside Soils; Platinum, Palladium and Rhodium in a Bavarian Roadside Soil; Increase of Platinum Group Element Concentrations in Soils and Airborne Dust During the Period of Vehicular Exhaust Catalysts Introduction; Platinum-Group Elements in Urban Fluvial Bed Sediments-Hawaii; Long-Term Monitoring of Palladium and Platinum Contents in Road Dust of the City of Munich, Germany; Characterization of PGEs and Other Elements in Road Dusts and Airborne Particles in Houston, Texas; Accumulation and Distribution of Pt and Pd in Roadside Dust, Soil and Vegetation in Bulgaria; Increase of the Environmental Pt Concentration in the Metropolitan Area of Mexico City Associated to the Use of Automobile Catalytic Converters; Solubility of Emitted Platinum Group Elements (Pt, Pd and Rh) in Airborne Particulate Matter (PM10) in the Presence of Organic Complexing Agents; The Influence of Anionic Species (Cl{sup -}, NO{sub 3}{sup -}, SO{sub 4}{sup 2-}) on the Transformation and Solubility of Platinum in

  4. Depleted Uranium Hexafluoride Management Program. The technology assessment report for the long-term management of depleted uranium hexafluoride. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Zoller, J.N.; Rosen, R.S.; Holliday, M.A. [and others

    1995-06-30

    With the publication of a Request for Recommendations and Advance Notice of Intent in the November 10, 1994 Federal Register, the Department of Energy initiated a program to assess alternative strategies for the long-term management or use of depleted uranium hexafluoride. This Request was made to help ensure that, by seeking as many recommendations as possible, Department management considers reasonable options in the long-range management strategy. The Depleted Uranium Hexafluoride Management Program consists of three major program elements: Engineering Analysis, Cost Analysis, and an Environmental Impact Statement. This Technology Assessment Report is the first part of the Engineering Analysis Project, and assesses recommendations from interested persons, industry, and Government agencies for potential uses for the depleted uranium hexafluoride stored at the gaseous diffusion plants in Paducah, Kentucky, and Portsmouth, Ohio, and at the Oak Ridge Reservation in Tennessee. Technologies that could facilitate the long-term management of this material are also assessed. The purpose of the Technology Assessment Report is to present the results of the evaluation of these recommendations. Department management will decide which recommendations will receive further study and evaluation.

  5. Depleted Uranium Hexafluoride Management Program. The technology assessment report for the long-term management of depleted uranium hexafluoride. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Zoller, J.N.; Rosen, R.S.; Holliday, M.A. [and others

    1995-06-30

    With the publication of a Request for Recommendations and Advance Notice of Intent in the November 10, 1994 Federal Register, the Department of Energy initiated a program to assess alternative strategies for the long-term management or use of depleted uranium hexafluoride. This Request was made to help ensure that, by seeking as many recommendations as possible, Department management considers reasonable options in the long-range management strategy. The Depleted Uranium Hexafluoride Management Program consists of three major program elements: Engineering Analysis, Cost Analysis, and an Environmental Impact Statement. This Technology Assessment Report is the first part of the Engineering Analysis Project, and assesses recommendations from interested persons, industry, and Government agencies for potential uses for the depleted uranium hexafluoride stored at the gaseous diffusion plants in Paducah, Kentucky, and Portsmouth, Ohio, and at the Oak Ridge Reservation in Tennessee. Technologies that could facilitate the long-term management of this material are also assessed. The purpose of the Technology Assessment Report is to present the results of the evaluation of these recommendations. Department management will decide which recommendations will receive further study and evaluation. These Appendices contain the Federal Register Notice, comments on evaluation factors, independent technical reviewers resumes, independent technical reviewers manual, and technology information packages.

  6. Stochastic models for turbulent reacting flows

    Energy Technology Data Exchange (ETDEWEB)

    Kerstein, A. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    The goal of this program is to develop and apply stochastic models of various processes occurring within turbulent reacting flows in order to identify the fundamental mechanisms governing these flows, to support experimental studies of these flows, and to further the development of comprehensive turbulent reacting flow models.

  7. Pattern of explosive reaction between uranium hexafluoride and hydrocarbon oils. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, K.E.

    1986-03-21

    Examination of uranium hexafluoride release incidents occurring over the past three decades of ORGDP experience has identified only four which apparently involved an explosion of a container resulting from reaction between uranium hexafluoride and an impurity. These four incidents exhibit a certain degree of commonality. Each has involved: (1) condensed phase uranium hexafluoride, (2) a moderately elevated temperature, (3) a sufficient quantity of uranium hexafluoride for a significant partial pressure to be maintained independently above that which can be consumed by chemical reaction, and (4) an organic liquid (probably hydrocarbon oil) accidentally present in the container as a contaminant. The purpose of this investigative search was to establish some conditional pattern for these four incidents to which their violent consequences could be attributed. Fortunately, the number of such incidents is relatively small, which emphasizes even more pointedly the unfortunate fact that documentation ranges from thorough to very limited. Documented sources of information are given in the bibliography. Copies of those which are not readily available are contained in six appendices. 8 refs.

  8. Sulfur containing platinum(II) complexes with N-heterocyclic carbene ligands obtained by reactions of a hydrosulfido complex.

    Science.gov (United States)

    Maeda, Yuri; Hashimoto, Hideki; Nishioka, Takanori

    2012-10-21

    A hydrosulfido platinum(ii) complex with a chelated N-heterocyclic carbene (NHC) ligand was oxidised with O(2) in the presence of excess hydrogen sulfide, to give a linear tetrasulfido complex, and without hydrogen sulfide, to give a thiosulfato-bridged dinuclear complex. The hydrosulfido complex also reacted with an acetato complex containing the chelating NHC platinum unit to afford a trinuclear platinum complex with two triply bridging sulfido ligands showing an equilibrium in solution between two isomers based on the arrangement of the chelating NHC ligands.

  9. Platinum nitride with fluorite structure

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Rong; Zhang, Xiao-Feng

    2005-01-31

    The mechanical stability of platinum nitride has been studied using first-principles calculations. By calculating the single-crystal elastic constants, we show that platinum nitride can be stabilized in the fluorite structure, in which the nitrogen atoms occupy all the tetrahedral interstitial sites of the metal lattice. The stability is attributed to the pseudogap effect from analysis of the electronic structure.

  10. [Simultaneous determination of platinum (IV) and palladium (II) using spectrophotometry method].

    Science.gov (United States)

    Ma, Dong-Lan; Wang, Yun; Ma, Kuang-Biao; Wang, Jin-Ye

    2009-10-01

    The N-(m-methylphenyl)-N'-(sodium p-aminobenzenesulfonate)-thiourea (MMPT) was good reagent of water solubility. In the medium of an HAc-NaAc buffer solution and hexadecyltrimethylammonium bromide (CTMAB), MMPT can react with platinum (IV) and palladium (II) to form green and brown soluble complex. The maximum absorbance of the complex was at lambdaPt(max) = 754.4 nm and lambdaPD(max) = 304.6 nm. Beer's law was obeyed with the concentration in the range of 0-32.0 microg Pt(IV)/25 mL and 0-25.0 microg Pd(II)/25 mL for platinum (IV) and palladium(II) respectively. The correlated coefficient was r754.4 = 0.999 5 for platinum (IV); and r304.6 = 0.999 9 for palladium (II). Their molar absorption coefficients were epsilonPT(754.4 = 8.6 x 10(4) L x mol(-1) x cm(-1) and epsilonPd(304.6) = 7.4 x 10(4) L x mol(-1) x cm(-1) respectively. The contents of platinum (IV) and palladium (II) were converted by determination of the absorbency of mix solution of platinum (IV) and palladium (II) at 754.4 and 304.6 nm. Only Cu2+ and Co2+ interfered with the determination of palladium (II) among 50 coexistent ions, so the selectivity was good. It can be used for the determination of content of synthesis samples. The relative standard deviation (RSD) was less than 2.0%, and the recovery (%) was in the range of 96%-104%. The results are satisfactory. Because the reagent reacts with platinum (IV) and palladium (II) to form water soluble complex and does not require pre-separation for simultaneous determination of platinum (IV) and palladium (II), the method is easy to operate, rapid and environment-friendly.

  11. SYNTHESIS AND CATALYTIC BEHAVIOR OF POLYSILOXANE-SUPPORTED FULLERENE PLATINUM OR RHODIUM COMPLEXES

    Institute of Scientific and Technical Information of China (English)

    Peng-fei Fang; Yuan-yin Chen; Shu-ling Gong; Lei Guo; Qiu-sheng Lu; Ling Zhu

    1999-01-01

    Two polysiloxanes with pendant fullerene moieties and their platinum or rhodium complexes have been prepared from C60 via amination with ω-decenylamine, followed by hydrosilylation with triethoxysilane and immobilization on fumed silica or by hydrosilylation with methyldichlorosilane and polycondensation with polydimethylsiloxanol, and then by reacting them with potassium chloroplatinite or rhodium chloride in acetone respectively under argon atmosphere. It was found that the four noble metal complexes are effective catalysts for the hydrosilylation of olefins with triethoxysilane. The regioselectivity of platinum complexes for styrene increases remarkably by introducing C60 moiety. Factors influencing catalytic activity and the mechanism have been investigated.

  12. Nanosecond discharge in sulfur hexafluoride and the generation of an ultrashort avalanche electron beam

    Science.gov (United States)

    Baksht, E. Kh.; Burachenko, A. G.; Erofeev, M. V.; Lomaev, M. I.; Rybka, D. V.; Sorokin, D. A.; Tarasenko, V. F.

    2008-06-01

    A discharge in the presence of a nonuniform electric field and the generation of an ultrashort avalanche electron beam (UAEB) are studied in the insulating gas SF6 at the pressures 0.01 2.50 atm. High-voltage nanosecond pulses (about 150 and 250 kV) and the voltage pulses with an amplitude of 25 kV and a duration of tens of nanoseconds are applied across the gap. An electron beam is obtained behind the AlBe foil with a thickness of 45 μm at a sulfur hexafluoride pressure in a gas-filled diode of up to 2 atm. It is demonstrated that, at relatively high pressures (greater than 1 atm) and in the presence of high-voltage nanosecond pulses across the gap, the UAEB pulse FWHM increases. The spectra of the diffuse and contracted discharges in sulfur hexafluoride are measured.

  13. Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of uranium hexafluoride

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 These test methods cover procedures for subsampling and for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of uranium hexafluoride UF6. Most of these test methods are in routine use to determine conformance to UF6 specifications in the Enrichment and Conversion Facilities. 1.2 The analytical procedures in this document appear in the following order: Note 1—Subcommittee C26.05 will confer with C26.02 concerning the renumbered section in Test Methods C761 to determine how concerns with renumbering these sections, as analytical methods are replaced with stand-alone analytical methods, are best addressed in subsequent publications. Sections Subsampling of Uranium Hexafluoride 7 - 10 Gravimetric Determination of Uranium 11 - 19 Titrimetric Determination of Uranium 20 Preparation of High-Purity U3O 8 21 Isotopic Analysis 22 Isotopic Analysis by Double-Standard Mass-Spectrometer Method 23 - 29 Determination of Hydrocarbons, Chlorocarbons, and Partially Substitut...

  14. Understanding platinum-induced ototoxicity.

    Science.gov (United States)

    Langer, Thorsten; am Zehnhoff-Dinnesen, Antoinette; Radtke, Susanne; Meitert, Johannes; Zolk, Oliver

    2013-08-01

    Childhood cancer survival rates are now nearly 80% in more developed European countries because of improved therapies and better supportive care. Platinum chemotherapy drugs, such as cisplatin and carboplatin, are the cornerstone of many effective therapeutic protocols for childhood cancer. However, the antitumor efficacy of cisplatin and carboplatin comes at the cost of ototoxicity, which affects at least 60% of pediatric patients. Although ototoxicity is not life threatening, it can have debilitating effects on patients' quality of life. Recently, many initiatives have been launched with the ultimate goal of reducing cisplatin and high-dose carboplatin ototoxicity without compromising antitumor efficacy. This review addresses the incidence of platinum ototoxicity and its clinical presentation, time course, and early diagnostic evaluation. Genetic and non-genetic risk factors for platinum-associated ototoxicity, and their predictive value, are discussed. Recent developments in the prevention of platinum ototoxicity are also summarized. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Quantitative visualization of the chemical reacting JET

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, K.; Arata, Y.; Sasaki, T.; Madarame, H. [Nuclear Engineering Research Laboratory, Tokyo Univ., Tokai, Ibaraki (Japan)

    2000-10-01

    The sodium-water reaction should be precisely evaluated for the safety analysis of the sodium-cooled nuclear power plant. To evaluate these chemical reacting jet, the characteristics of the reaction and the mole fraction distributions of the reacting material should be known. In this study, to evaluate the basic characteristics, two fluid jet and chemical reacting jet was measured by the PIV and DELIF. The new dye pair for the dual emission LIF technique was proposed to measure the pH distribution. The Quinine for pH sensitive dye with blue emission and Rhodamine 6G for non-sensitive dye with orange emission, were excited by the third harmonic of Nd:YAG laser (355nm). The high accurate measurement could be achieved for the range of pH 4.0 to 5.5. The ammonia jet into acetic acid was measured using the proposed dye. The effectiveness of the present method was demonstrated. (author)

  16. Calorimetry of non-reacting systems

    CERN Document Server

    McCullough, John P

    2013-01-01

    Experimental Thermodynamics, Volume 1: Calorimetry of Non-Reacting Systems covers the heat capacity determinations for chemical substances in the solid, liquid, solution, and vapor states, at temperatures ranging from near the absolute zero to the highest at which calorimetry is feasible.This book is divided into 14 chapters. The first four chapters provide background information and general principles applicable to all types of calorimetry of non-reacting systems. The remaining 10 chapters deal with specific types of calorimetry. Most of the types of calorimetry treated are developed over a c

  17. Inorganic nanocarriers for platinum drug delivery

    Directory of Open Access Journals (Sweden)

    Ping’an Ma

    2015-12-01

    Full Text Available Nowadays platinum drugs take up almost 50% of all the clinically used anticancer drugs. Besides cisplatin, novel platinum agents including sterically hindered platinum (II drugs, chemically reductive platinum (IV drugs, photosensitive platinum (IV drugs, and multinuclear platinum drugs have been developed recently, with a few entering clinic trials. Rapid development of nanobiotechnology makes targeted delivery of anticancer platinum agents to the tumor site possible, while simultaneously minimizing toxicity and maximizing the drug efficacy. Being versatile drug carriers to deliver platinum drugs, inorganic nanovehicles such as gold nanoparticles, iron oxide nanomaterials, carbon nanotubes, mesoporous nanosilica, metal-organic frameworks (MOFs, have been extensively studied over the past decades. In contrast to conventional polymeric and lipid nanoparticles, inorganic nanoparticles based drug carriers are peculiar as they have shown excellent theranostic effects, revealing themselves an indispensable part of future nanomedicine. Here, we will elaborate recent research advances on fabrication of inorganic nanoparticles for platinum drug delivery.

  18. Platinum availability for future automotive technologies.

    Science.gov (United States)

    Alonso, Elisa; Field, Frank R; Kirchain, Randolph E

    2012-12-04

    Platinum is an excellent catalyst, can be used at high temperatures, and is stable in many aggressive chemical environments. Consequently, platinum is used in many current industrial applications, notably automotive catalytic converters, and prospective vehicle fuel cells are expected to rely upon it. Between 2005 and 2010, the automotive industry used approximately 40% of mined platinum. Future automotive industry growth and automotive sales shifts toward new technologies could significantly alter platinum demand. The potential risks for decreased platinum availability are evaluated, using an analysis of platinum market characteristics that describes platinum's geophysical constraints, institutional efficiency, and dynamic responsiveness. Results show that platinum demand for an automotive fleet that meets 450 ppm greenhouse gas stabilization goals would require within 10% of historical growth rates of platinum supply before 2025. However, such a fleet, due largely to sales growth in fuel cell vehicles, will more strongly constrain platinum supply in the 2050 time period. While current platinum reserves are sufficient to satisfy this increased demand, decreasing platinum ore grade and continued concentration of platinum supply in a single geographic area are availability risk factors to platinum end-users.

  19. Platinum-induced structural collapse in layered oxide polycrystalline films

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jianlin; Liu, Changhui [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Huang, Haoliang [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026 (China); Fu, Zhengping; Peng, Ranran, E-mail: pengrr@ustc.edu.cn, E-mail: yllu@ustc.edu.cn [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026 (China); Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026 (China); Zhai, Xiaofang [Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026 (China); Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026 (China); Lu, Yalin, E-mail: pengrr@ustc.edu.cn, E-mail: yllu@ustc.edu.cn [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026 (China); Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026 (China); Laser and Optics Research Center, Department of Physics, United States Air Force Academy, Colorado 80840 (United States)

    2015-03-30

    Effect of a platinum bottom electrode on the SrBi{sub 5}Fe{sub 1−x}Co{sub x}Ti{sub 4}O{sub 18} layered oxide polycrystalline films was systematically studied. The doped cobalt ions react with the platinum to form a secondary phase of PtCoO{sub 2}, which has a typical Delafossite structure with a weak antiferromagnetism and an exceptionally high in-plane electrical conductivity. Formation of PtCoO{sub 2} at the interface partially consumes the cobalt dopant and leads to the structural collapsing from 5 to 4 layers, which was confirmed by X-ray diffraction and high resolution transmission electron microscopy measurements. Considering the weak magnetic contribution from PtCoO{sub 2}, the observed ferromagnetism should be intrinsic of the Aurivillius compounds. Ferroelectric properties were also indicated by the piezoresponse force microscopy. In this work, the platinum induced secondary phase at the interface was observed, which has a strong impact on Aurivillius structural configuration and thus the ferromagnetic and ferroelectric properties.

  20. Cross-reactivity of Halogenated Platinum Salts

    Science.gov (United States)

    Halogenated platinum (Pt) salts are well-known respiratory sensitizers associated with the development of asthma. People may be exposed to a variety of platinum compounds in different contexts (e.g. occupationally, automobile exhaust). Published reports suggest that sensitizati...

  1. Numerical Methods For Chemically Reacting Flows

    Science.gov (United States)

    Leveque, R. J.; Yee, H. C.

    1990-01-01

    Issues related to numerical stability, accuracy, and resolution discussed. Technical memorandum presents issues in numerical solution of hyperbolic conservation laws containing "stiff" (relatively large and rapidly changing) source terms. Such equations often used to represent chemically reacting flows. Usually solved by finite-difference numerical methods. Source terms generally necessitate use of small time and/or space steps to obtain sufficient resolution, especially at discontinuities, where incorrect mathematical modeling results in unphysical solutions.

  2. Algorithm For Computation Of Chemically Reacting Flow

    Science.gov (United States)

    Chen, Yen-Sen; Chen, Chein-Pin; Shang, Huan-Min

    1995-01-01

    Efficient algorithm developed for use in solving differential equations of transient, chemically reacting flows at all speeds from zero to high mach numbers. Mathematical models represent coupling of thermal, chemical, and dynamical effects. Original intended application is numerical simulation of flows in rocket engines; also applicable to other complex flows affected by finite-rate chemistry - for example, flows in turbines and in internal-combustion engines.

  3. A constitutive theory of reacting electrolyte mixtures

    Science.gov (United States)

    Costa Reis, Martina; Wang, Yongqi; Bono Maurizio Sacchi Bassi, Adalberto

    2013-11-01

    A constitutive theory of reacting electrolyte mixtures is formulated. The intermolecular interactions among the constituents of the mixture are accounted for through additional freedom degrees to each constituent of the mixture. Balance equations for polar reacting continuum mixtures are accordingly formulated and a proper set of constitutive equations is derived with basis in the Müller-Liu formulation of the second law of thermodynamics. Moreover, the non-equilibrium and equilibrium responses of the reacting mixture are investigated in detail by emphasizing the inner and reactive structures of the medium. From the balance laws and constitutive relations, the effects of molecular structure of constituents upon the fluid flow are studied. It is also demonstrated that the local thermodynamic equilibrium state can be reached without imposing that the set of independent constitutive variables is time independent, neither spatially homogeneous nor null. The resulting constitutive relations presented throughout this work are of relevance to many practical applications, such as swelling of clays, developing of bio and polymeric membranes, and use of electrorheological fluids in industrial processes. The first author acknowledges financial support from National Counsel of Technological and Scientific Development (CNPq) and German Academic Exchange Service (DAAD).

  4. Novel non-platinum metal catalyst material

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a novel non-platinum metal catalyst material for use in low temperature fuel cells and electrolysers and to fuel cells and electrolysers comprising the novel non-platinum metal catalyst material. The present invention also relates to a novel method for synthesizing...... the novel non-platinum metal catalyst material....

  5. Coating Carbon Fibers With Platinum

    Science.gov (United States)

    Effinger, Michael R.; Duncan, Peter; Coupland, Duncan; Rigali, Mark J.

    2007-01-01

    A process for coating carbon fibers with platinum has been developed. The process may also be adaptable to coating carbon fibers with other noble and refractory metals, including rhenium and iridium. The coated carbon fibers would be used as ingredients of matrix/fiber composite materials that would resist oxidation at high temperatures. The metal coats would contribute to oxidation resistance by keeping atmospheric oxygen away from fibers when cracks form in the matrices. Other processes that have been used to coat carbon fibers with metals have significant disadvantages: Metal-vapor deposition processes yield coats that are nonuniform along both the lengths and the circumferences of the fibers. The electrical resistivities of carbon fibers are too high to be compatible with electrolytic processes. Metal/organic vapor deposition entails the use of expensive starting materials, it may be necessary to use a furnace, and the starting materials and/or materials generated in the process may be hazardous. The present process does not have these disadvantages. It yields uniform, nonporous coats and is relatively inexpensive. The process can be summarized as one of pretreatment followed by electroless deposition. The process consists of the following steps: The surfaces of the fiber are activated by deposition of palladium crystallites from a solution. The surface-activated fibers are immersed in a solution that contains platinum. A reducing agent is used to supply electrons to effect a chemical reduction in situ. The chemical reduction displaces the platinum from the solution. The displaced platinum becomes deposited on the fibers. Each platinum atom that has been deposited acts as a catalytic site for the deposition of another platinum atom. Hence, the deposition process can also be characterized as autocatalytic. The thickness of the deposited metal can be tailored via the duration of immersion and the chemical activity of the solution.

  6. Platinum Group Metals New Material

    Institute of Scientific and Technical Information of China (English)

    XIE Ming; ZHANG Jiankang; WANG Saibei; HU Jieqiong; LIU Manmen; CHEN Yongtai; ZHANG Jiming; YANG Youcai; YANG Yunfeng; ZHANG Guoquan

    2012-01-01

    Platinum group metals (PGM) include six elements,namely Pt,Pd,Rh,Ir,Os and Ru.PGM and their alloys are the important fundamental materials for modern industry and national defense construction,they have special physical and chemical properties,widely used in metallurgy,chemical,electric,electronic,information,energy,environmental protection,aviation,aerospace,navigation and other high technology industry.Platinum group metals and their alloys,which have good plasticity and processability,can be processed to electrical contact materials,resistance materials,solder,electronic paste,temperature-measurement materials,elastic materials,magnetic materials and high temperature structural materials.

  7. Compilation of Requirements for Safe Handling of Fluorine and Fluorine-Containing Products of Uranium Hexafluoride Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Ferrada, J.J.

    2000-04-03

    Public Law (PL) 105-204 requires the U.S. Department of Energy to develop a plan for inclusion in the fiscal year 2000 budget for conversion of the Department's stockpile of depleted uranium hexafluoride (DUF{sub 6}) to a more stable form over an extended period. The conversion process into a more stable form will produce fluorine compounds (e.g., elemental fluorine or hydrofluoric acid) that need to be handled safely. This document compiles the requirements necessary to handle these materials within health and safety standards, which may apply in order to ensure protection of the environment and the safety and health of workers and the public. Fluorine is a pale-yellow gas with a pungent, irritating odor. It is the most reactive nonmetal and will react vigorously with most oxidizable substances at room temperature, frequently with ignition. Fluorine is a severe irritant of the eyes, mucous membranes, skin, and lungs. In humans, the inhalation of high concentrations causes laryngeal spasm and broncospasms, followed by the delayed onset of pulmonary edema. At sublethal levels, severe local irritation and laryngeal spasm will preclude voluntary exposure to high concentrations, unless the individual is trapped or incapacitated. A blast of fluorine gas on the shaved skin of a rabbit causes a second degree burn. Lower concentrations cause severe burns of insidious onset, resulting in ulceration, similar to the effects produced by hydrogen fluoride. Hydrofluoric acid is a colorless, fuming liquid or gas with a pungent odor. It is soluble in water with release of heat. Ingestion of an estimated 1.5 grams produced sudden death without gross pathological damage. Repeated ingestion of small amounts resulted in moderately advanced hardening of the bones. Contact of skin with anhydrous liquid produces severe burns. Inhalation of AHA or aqueous hydrofluoric acid mist or vapors can cause severe respiratory tract irritation that may be fatal. Based on the extreme chemical

  8. Reduction of uranium hexafluoride to tetrafluoride by using the hydrogen atoms

    Science.gov (United States)

    Aleksandrov, B. P.; Gordon, E. B.; Ivanov, A. V.; Kotov, A. A.; Smirnov, V. E.

    2016-09-01

    We consider the reduction of UF6 to UF4 by chemical reaction with hydrogen atoms originated in the powerful chemical generator. The principal design of such a chemical convertor is described. The results of the mathematical modeling of the thermodynamics and kinetics of the UF6 to UF4 reduction process are analyzed. The few options for the hydrogen atom generator design are proposed. A layout of the experimental setup with the chemical reactor is presented. The high efficiency together with the ability of the process scaling without loss of its efficiency makes this approach to the uranium hexafluoride depletion into tetrafluoride promising for its application in the industry.

  9. Dipole-octopole polarizability of sulfur hexafluoride from isotropic and anisotropic light scattering experiments

    Science.gov (United States)

    El-Kader, M. S. A.; Bancewicz, T.

    2013-05-01

    The higher order dipole-octopole polarizability E of sulfur hexafluoride has been determined from isotropic and anisotropic collision-induced light scattering (CILS) experiments of pure SF6 gas and from anisotropic light scattering of its mixture with inert gases. The CILS spectra are analyzed by using the new updated and different intermolecular potentials. Our final estimates for this property is |E| = 96.405 ± 12.045 a.u. which is in excellent agreement with the ab initio theoretical value.

  10. Standard guide for determination of plutonium and neptunium in uranium hexafluoride by alpha spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This method covers the determination of plutonium and neptunium isotopes in uranium hexafluoride by alpha spectroscopy. The method can also be applicable to any matrix that may be converted to a nitric acid system. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory requirements prior to use.

  11. Reactivity of monofunctional cis-platinum adducts as a function of DNA sequence.

    Science.gov (United States)

    Malinge, J M; Leng, M

    1988-08-11

    The purpose of this work was to study the chemical reactivity of monofunctional cis-platinum-nucleic acid adducts as a function of nucleic acid sequence. The first part of the paper deals with the formation of these adducts. It is shown that the ternary nucleic acid-cis-platinum-ethidium bromide complexes in which ethidium bromide and nucleotide residues are cross-linked by cis-platinum, are relatively unstable at 37 degrees C. In the presence of acridine, ethidium bromide (but not cis-platinum) is slowly released which leads to the formation of monofunctional cis-platinum-nucleic acid adducts. After removal of acridine, the monofunctional adducts react further to become bifunctional. The second part of the paper deals with the kinetics of disappearance of the monofunctional adducts in several polynucleotides but not in poly(dG).poly(dC). When the adducts possess a chloride ligand, the limiting step in the cross-linking is the rate of aquation reaction of the chloride ligand. The rate constants are an order of magnitude larger when the monofunctional adducts do not possess a chloride ligand. In both the cases, the rate constants are apparently independent of the nucleic acid sequence.

  12. Turbulent diffusion of chemically reacting gaseous admixtures

    Science.gov (United States)

    Elperin, T.; Kleeorin, N.; Liberman, M.; Rogachevskii, I.

    2014-11-01

    We study turbulent diffusion of chemically reacting gaseous admixtures in a developed turbulence. In our previous study [Phys. Rev. Lett. 80, 69 (1998), 10.1103/PhysRevLett.80.69] using a path-integral approach for a delta-correlated in a time random velocity field, we demonstrated a strong modification of turbulent transport in fluid flows with chemical reactions or phase transitions. In the present study we use the spectral τ approximation that is valid for large Reynolds and Peclet numbers and show that turbulent diffusion of the reacting species can be strongly depleted by a large factor that is the ratio of turbulent and chemical times (turbulent Damköhler number). We have demonstrated that the derived theoretical dependence of a turbulent diffusion coefficient versus the turbulent Damköhler number is in good agreement with that obtained previously in the numerical modeling of a reactive front propagating in a turbulent flow and described by the Kolmogorov-Petrovskii-Piskunov-Fisher equation. We have found that turbulent cross-effects, e.g., turbulent mutual diffusion of gaseous admixtures and turbulent Dufour effect of the chemically reacting gaseous admixtures, are less sensitive to the values of stoichiometric coefficients. The mechanisms of the turbulent cross-effects differ from the molecular cross-effects known in irreversible thermodynamics. In a fully developed turbulence and at large Peclet numbers the turbulent cross-effects are much larger than the molecular ones. The obtained results are applicable also to heterogeneous phase transitions.

  13. Nanocarriers for delivery of platinum anticancer drugs☆

    Science.gov (United States)

    Oberoi, Hardeep S.; Nukolova, Natalia V.; Kabanov, Alexander V.; Bronich, Tatiana K.

    2014-01-01

    Platinum based anticancer drugs have revolutionized cancer chemotherapy, and continue to be in widespread clinical use especially for management of tumors of the ovary, testes, and the head and neck. However, several dose limiting toxicities associated with platinum drug use, partial anti-tumor response in most patients, development of drug resistance, tumor relapse, and many other challenges have severely limited the patient quality of life. These limitations have motivated an extensive research effort towards development of new strategies for improving platinum therapy. Nanocarrier-based delivery of platinum compounds is one such area of intense research effort beginning to provide encouraging preclinical and clinical results and may allow the development of the next generation of platinum chemotherapy. This review highlights current understanding on the pharmacology and limitations of platinum compounds in clinical use, and provides a comprehensive analysis of various platinum–polymer complexes, micelles, dendrimers, liposomes and other nanoparticles currently under investigation for delivery of platinum drugs. PMID:24113520

  14. Stability of compressible reacting mixing layer

    Science.gov (United States)

    Shin, D. S.; Ferziger, J. H.

    1991-01-01

    Linear instability of compressible reacting mixing layers is analyzed with emphasis on the effects of heat release and compressibility. Laminar solutions of the compressible boundary-layer equations are used as the base flows. The parameters of this study are the adiabatic flame temperature, the Mach number of the upper stream, frequency, wavenumber, and the direction of propagation of the disturbance wave. Stability characteristics of the flow are presented. Three groups of unstable modes are found when the Mach number and/or heat release are large. Finally, it is shown that the unstable modes are two-dimensional for large heat release even in highly compressible flow.

  15. [Formylation of porphyrin platinum complexes].

    Science.gov (United States)

    Rumiantseva, V D; Konovalenko, L I; Nagaeva, E A; Mironov, A F

    2005-01-01

    The formylation reaction of platinum complexes of beta-unsubstituted porphyrins was studied. The interaction of deuteroporphyrin IX derivatives with the Vilsmeyer reagent led to the selective formylation of their macrocycles in the beta position. The resulting formyl derivatives of the porphyrins are of interest for fluorescent immunoassay.

  16. Geological conditions of safe long-term storage and disposal of depleted uranium hexafluoride

    Science.gov (United States)

    Laverov, N. P.; Velichkin, V. I.; Omel'Yanenko, B. I.; Yudintsev, S. V.; Tagirov, B. R.

    2010-08-01

    The production of enriched uranium used in nuclear weapons and fuel for atomic power plants is accompanied by the formation of depleted uranium (DU), the amount of which annually increases by 35-40 kt. To date, more than 1.6 Mt DU has accumulated in the world. The main DU mass is stored as environ-mentally hazardous uranium hexafluoride (UF6), which is highly volatile and soluble in water with the formation of hydrofluoric acid. To ensure safe UF6 storage, it is necessary to convert this compound in chemically stable phases. The industrial reprocessing of UF6 into U3O8 and HF implemented in France is highly expensive. We substantiate the expediency of long-term storage of depleted uranium hexafluoride in underground repositories localized in limestone. On the basis of geochemical data and thermodynamic calculations, we show that interaction in the steel container-UF6-limestone-groundwater system gives rise to the development of a slightly alkaline reductive medium favorable for chemical reaction with formation of uraninite (UO2) and fluorite (CaF2). The proposed engineering solution not only ensures safe DU storage but also makes it possible to produce uraninite, which can be utilized, if necessary, in fast-neutron reactors. In the course of further investigations aimed at safe maintenance of DU, it is necessary to study the kinetics of conversion of UF6 into stable phases, involving laboratory and field experiments.

  17. Chemical toxicity of uranium hexafluoride compared to acute effects of radiation

    Energy Technology Data Exchange (ETDEWEB)

    McGuire, S.A.

    1991-02-01

    The chemical effects from acute exposures to uranium hexafluoride are compared to the nonstochastic effects from acute radiation doses of 25 rems to the whole body and 300 rems to the thyroid. The analysis concludes that an intake of about 10 mg of uranium in soluble form is roughly comparable, in terms of early effects, to an acute whole body dose of 25 rems because both are just below the threshold for significant nonstochastic effects. Similarly, an exposure to hydrogen fluoride at a concentration of 25 mg/m{sup 3} for 30 minutes is roughly comparable because there would be no significant nonstochastic effects. For times t other than 30 minutes, the concentration C of hydrogen fluoride considered to have the same effect can be calculated using a quadratic equation: C = 25 mg/m{sup 3} (30 min/t). The purpose of these analyses is to provide information for developing design and siting guideline based on chemical toxicity for enrichment plants using uranium hexafluoride. These guidelines are to be similar, in terms of stochastic health effects, to criteria in NRC regulations of nuclear power plants, which are based on radiation doses. 26 refs., 1 fig., 5 tabs.

  18. Facilities GIS Modeling for the REACT System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Real-Time Emergency Action Coordination Tool (REACT) was developed under contract to NASA and deployed for use by the entire agency.  NASA REACT is a...

  19. PDF approach for compressible turbulent reacting flows

    Science.gov (United States)

    Hsu, A. T.; Tsai, Y.-L. P.; Raju, M. S.

    1993-01-01

    The objective of the present work is to develop a probability density function (pdf) turbulence model for compressible reacting flows for use with a CFD flow solver. The probability density function of the species mass fraction and enthalpy are obtained by solving a pdf evolution equation using a Monte Carlo scheme. The pdf solution procedure is coupled with a compressible CFD flow solver which provides the velocity and pressure fields. A modeled pdf equation for compressible flows, capable of capturing shock waves and suitable to the present coupling scheme, is proposed and tested. Convergence of the combined finite-volume Monte Carlo solution procedure is discussed, and an averaging procedure is developed to provide smooth Monte-Carlo solutions to ensure convergence. Two supersonic diffusion flames are studied using the proposed pdf model and the results are compared with experimental data; marked improvements over CFD solutions without pdf are observed. Preliminary applications of pdf to 3D flows are also reported.

  20. Pdf - Transport equations for chemically reacting flows

    Science.gov (United States)

    Kollmann, W.

    1989-01-01

    The closure problem for the transport equations for pdf and the characteristic functions of turbulent, chemically reacting flows is addressed. The properties of the linear and closed equations for the characteristic functional for Eulerian and Lagrangian variables are established, and the closure problem for the finite-dimensional case is discussed for pdf and characteristic functions. It is shown that the closure for the scalar dissipation term in the pdf equation developed by Dopazo (1979) and Kollmann et al. (1982) results in a single integral, in contrast to the pdf, where double integration is required. Some recent results using pdf methods obtained for turbulent flows with combustion, including effects of chemical nonequilibrium, are discussed.

  1. Multiphase reacting flows modelling and simulation

    CERN Document Server

    Marchisio, Daniele L

    2007-01-01

    The papers in this book describe the most widely applicable modeling approaches and are organized in six groups covering from fundamentals to relevant applications. In the first part, some fundamentals of multiphase turbulent reacting flows are covered. In particular the introduction focuses on basic notions of turbulence theory in single-phase and multi-phase systems as well as on the interaction between turbulence and chemistry. In the second part, models for the physical and chemical processes involved are discussed. Among other things, particular emphasis is given to turbulence modeling strategies for multiphase flows based on the kinetic theory for granular flows. Next, the different numerical methods based on Lagrangian and/or Eulerian schemes are presented. In particular the most popular numerical approaches of computational fluid dynamics codes are described (i.e., Direct Numerical Simulation, Large Eddy Simulation, and Reynolds-Averaged Navier-Stokes approach). The book will cover particle-based meth...

  2. Mathematical aspects of reacting and diffusing systems

    CERN Document Server

    Fife, Paul C

    1979-01-01

    Modeling and analyzing the dynamics of chemical mixtures by means of differ- tial equations is one of the prime concerns of chemical engineering theorists. These equations often take the form of systems of nonlinear parabolic partial d- ferential equations, or reaction-diffusion equations, when there is diffusion of chemical substances involved. A good overview of this endeavor can be had by re- ing the two volumes by R. Aris (1975), who himself was one of the main contributors to the theory. Enthusiasm for the models developed has been shared by parts of the mathematical community, and these models have, in fact, provided motivation for some beautiful mathematical results. There are analogies between chemical reactors and certain biological systems. One such analogy is rather obvious: a single living organism is a dynamic structure built of molecules and ions, many of which react and diffuse. Other analogies are less obvious; for example, the electric potential of a membrane can diffuse like a chemical, and ...

  3. Quick-Mixing Studies Under Reacting Conditions

    Science.gov (United States)

    Leong, May Y.; Samuelsen, G. S.

    1996-01-01

    The low-NO(x) emitting potential of rich-burn/quick-mix/lean-burn )RQL) combustion makes it an attractive option for engines of future stratospheric aircraft. Because NO(x) formation is exponentially dependent on temperature, the success of the RQL combustor depends on minimizing high temperature stoichiometric pocket formation in the quick-mixing section. An experiment was designed and built, and tests were performed to characterize reaction and mixing properties of jets issuing from round orifices into a hot, fuel-rich crossflow confined in a cylindrical duct. The reactor operates on propane and presents a uniform, non-swirling mixture to the mixing modules. Modules consisting of round orifice configurations of 8, 9, 10, 12, 14, and 18 holes were evaluated at a momentum-flux ratio of 57 and jet-to-mainstream mass-flaw ratio of 2.5. Temperatures and concentrations of O2, CO2, CO, HC, and NO(x) were obtained upstream, down-stream, and within the orifice plane to determine jet penetration as well as reaction processes. Jet penetration was a function of the number of orifices and affected the mixing in the reacting system. Of the six configurations tested, the 14-hole module produced jet penetration close to the module half-radius and yielded the best mixing and most complete combustion at a plane one duct diameter from the orifice leading edge. The results reveal that substantial reaction and heat release occur in the jet mixing zone when the entering effluent is hot and rich, and that the experiment as designed will serve to explore satisfactorily jet mixing behavior under realistic reacting conditions in future studies.

  4. Quantitative imaging of turbulent and reacting flows

    Energy Technology Data Exchange (ETDEWEB)

    Paul, P.H. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    Quantitative digital imaging, using planar laser light scattering techniques is being developed for the analysis of turbulent and reacting flows. Quantitative image data, implying both a direct relation to flowfield variables as well as sufficient signal and spatial dynamic range, can be readily processed to yield two-dimensional distributions of flowfield scalars and in turn two-dimensional images of gradients and turbulence scales. Much of the development of imaging techniques to date has concentrated on understanding the requisite molecular spectroscopy and collision dynamics to be able to determine how flowfield variable information is encoded into the measured signal. From this standpoint the image is seen as a collection of single point measurements. The present effort aims at realizing necessary improvements in signal and spatial dynamic range, signal-to-noise ratio and spatial resolution in the imaging system as well as developing excitation/detection strategies which provide for a quantitative measure of particular flowfield scalars. The standard camera used for the study is an intensified CCD array operated in a conventional video format. The design of the system was based on detailed modeling of signal and image transfer properties of fast UV imaging lenses, image intensifiers and CCD detector arrays. While this system is suitable for direct scalar imaging, derived quantities (e.g. temperature or velocity images) require an exceptionally wide dynamic range imaging detector. To apply these diagnostics to reacting flows also requires a very fast shuttered camera. The authors have developed and successfully tested a new type of gated low-light level detector. This system relies on fast switching of proximity focused image-diode which is direct fiber-optic coupled to a cooled CCD array. Tests on this new detector show significant improvements in detection limit, dynamic range and spatial resolution as compared to microchannel plate intensified arrays.

  5. Direct numerical simulation of turbulent reacting flows

    Energy Technology Data Exchange (ETDEWEB)

    Chen, J.H. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    The development of turbulent combustion models that reflect some of the most important characteristics of turbulent reacting flows requires knowledge about the behavior of key quantities in well defined combustion regimes. In turbulent flames, the coupling between the turbulence and the chemistry is so strong in certain regimes that is is very difficult to isolate the role played by one individual phenomenon. Direct numerical simulation (DNS) is an extremely useful tool to study in detail the turbulence-chemistry interactions in certain well defined regimes. Globally, non-premixed flames are controlled by two limiting cases: the fast chemistry limit, where the turbulent fluctuations. In between these two limits, finite-rate chemical effects are important and the turbulence interacts strongly with the chemical processes. This regime is important because industrial burners operate in regimes in which, locally the flame undergoes extinction, or is at least in some nonequilibrium condition. Furthermore, these nonequilibrium conditions strongly influence the production of pollutants. To quantify the finite-rate chemistry effect, direct numerical simulations are performed to study the interaction between an initially laminar non-premixed flame and a three-dimensional field of homogeneous isotropic decaying turbulence. Emphasis is placed on the dynamics of extinction and on transient effects on the fine scale mixing process. Differential molecular diffusion among species is also examined with this approach, both for nonreacting and reacting situations. To address the problem of large-scale mixing and to examine the effects of mean shear, efforts are underway to perform large eddy simulations of round three-dimensional jets.

  6. Surface characterization of platinum electrodes.

    Science.gov (United States)

    Solla-Gullón, José; Rodríguez, Paramaconi; Herrero, Enrique; Aldaz, Antonio; Feliu, Juan M

    2008-03-14

    The quantitative analysis of the different surface sites on platinum samples is attempted from pure voltammetric data. This analysis requires independent knowledge of the fraction of two-dimensional (111) and (100) domains. Specific site-probe reactions are employed to achieve this goal. Irreversibly-adsorbed bismuth and tellurium have been revealed to be sensitive to the presence of (111) terrace domains of different width whereas almost all sites involved in (100) ordered domains have been characterized through germanium adatoms. The experimental protocol follows that used with well-defined single-crystal electrodes and, therefore, requires careful control of the surface cleanliness. Platinum basal planes and their vicinal stepped surfaces have been employed to obtain calibration plots between the charge density measured under the adatom redox peak, specific for the type of surface site, and the corresponding terrace size. The evaluation of the (100) bidimensional domains can also be achieved using the voltammetric profiles, once the fraction of (111) ordered domains present in the polyoriented platinum has been determined and their featureless contribution has been subtracted from the whole voltammetric response. Using that curve, it is possible to perform a deconvolution of the adsorption states of the polycrystalline sample different from those related to (111) domains. The fraction of (100)-related states in the deconvoluted voltammogram can then be compared to that expected from the independent estimation coming from the charge involved in the redox process undergone by the irreversibly-adsorbed germanium and thus check the result of the deconvolution. The information about the surface-site distribution can also be applied to analyze the voltammetric profile of nanocrystalline platinum electrodes.

  7. Request for Correction 11001 Toxicological Review of Halogenated Platinum Salts and Platinum Compounds

    Science.gov (United States)

    Request for Correction by the International Platinum Group Metals Association seeking the correction of information disseminated in the draft EPA document Toxicological Review of Halogenated Platinum Salts and Platinum Compounds: In Support of Summary Information on the Integrated Risk Information System (IRIS).

  8. Phosphoric acid fuel cell platinum use study

    Science.gov (United States)

    Lundblad, H. L.

    1983-01-01

    The U.S. Department of Energy is promoting the private development of phosphoric acid fuel cell (PAFC) power plants for terrestrial applications. Current PAFC technology utilizes platinum as catalysts in the power electrodes. The possible repercussions that the platinum demand of PAFC power plant commercialization will have on the worldwide supply and price of platinum from the outset of commercialization to the year 2000 are investigated. The platinum demand of PAFC commercialization is estimated by developing forecasts of platinum use per unit of generating capacity and penetration of PAFC power plants into the electric generation market. The ability of the platinum supply market to meet future demands is gauged by assessing the size of platinum reserves and the capability of platinum producers to extract, refine and market sufficient quantities of these reserves. The size and timing of platinum price shifts induced by the added demand of PAFC commercialization are investigated by several analytical methods. Estimates of these price shifts are then used to calculate the subsequent effects on PAFC power plant capital costs.

  9. On the reactivity of platinum(IV) complexes: Synthesis and spectroscopic studies of platinum(IV) complexes with hypoxanthine

    Science.gov (United States)

    Gaballa, Akmal S.

    2006-01-01

    Na 2[PtCl 6] was found to react with (HypH)Cl·H 2O ( 2) (Hyp=hypoxanthine) in aqueous solution at room temperature yielding (HypH) 2[PtCl 6] ( 3). The same compound was obtained from hexachloroplatinic acid and hypoxanthine. Performing this reaction in methanol at 50 °C complex formation took place yielding the hypoxanthine complex [PtCl 4(Hyp) 2] ( 4). Both compounds were isolated in good yields as faint orange ( 3) and yellow ( 4) precipitates, respectively and characterized by microanalyses, IR and NMR ( 1H, 13C, 195Pt) spectroscopies as well as thermal analysis. Based on the data obtained an octahedral molecular structure is proposed for complex 4 with two hypoxanthine ligands coordinated through N7 to platinum(IV).

  10. A Sulfur Hexafluoride Sensor Using Quantum Cascade and CO2 Laser-Based Photoacoustic Spectroscopy

    Directory of Open Access Journals (Sweden)

    Helion Vargas

    2010-10-01

    Full Text Available The increase in greenhouse gas emissions is a serious environmental problem and has stimulated the scientific community to pay attention to the need for detection and monitoring of gases released into the atmosphere. In this regard, the development of sensitive and selective gas sensors has been the subject of several research programs. An important greenhouse gas is sulphur hexafluoride, an almost non-reactive gas widely employed in industrial processes worldwide. Indeed it is estimated that it has a radiative forcing of 0.52 W/m2. This work compares two photoacoustic spectrometers, one coupled to a CO2 laser and another one coupled to a Quantum Cascade (QC laser, for the detection of SF6. The laser photoacoustic spectrometers described in this work have been developed for gas detection at small concentrations. Detection limits of 20 ppbv for CO2 laser and 50 ppbv for quantum cascade laser were obtained.

  11. Assessment of the risk of transporting uranium hexafluoride by truck and train

    Energy Technology Data Exchange (ETDEWEB)

    Geffen, C.A.; Johnson, J.F.; Davis, D.K.; Friley, J.R.; Ross, B.A.

    1978-08-01

    This report is the fifth in a series of studies of the risk of transporting potentially hazardous energy materials. The report presents an assessment of the risk of shipping uranium hexafluoride (UF/sub 6/) by truck and rail. The general risk assessment methodology, summarized in Section 3, used in this study is that developed for the first study in this series. The assessment includes the risks from release of uranium hexafluoride during truck or rail transport due to transportation accidents. The contribution to the risk of deteriorated or faulty packaging during normal transport was also considered. The report is sectioned to correspond to the specific analysis steps of the risk assessment model. The transportation system and accident environment are described in Sections 4 and 5. Calculation of the response of the shipping system to forces produced in transportation accidents are presented in Section 6 and the results of a survey to determine the condition of the package during transport are presented in Section 7. Sequences of events that could lead to a release of radioactive material from the shipping cask during transportation are postulated in Section 8 using fault tree analysis. These release sequences are evaluated in Sections 9 through 11, to determine both the likelihood and the possible consequences of each release. Supportive data and analyses are given in the appendices. The results of the risk assessment have been related to the year 1985, when it is projected that 100 GW of electric power will be generated annually by nuclear power plants. It was estimated that approximately 46,000 metric tons (MT) of natural UF/sub 6/ and 14,600 MT of enriched UF/sub 6/ would be shipped in the reference year.

  12. A Study on Reactive Ion Etching of Barium Strontium Titanate Films Using Mixtures of Argon (Ar), Carbon Tetrafluoride (CF4), and Sulfur Hexafluoride (SF6)

    Science.gov (United States)

    2014-07-01

    A Study on Reactive Ion Etching of Barium Strontium Titanate Films Using Mixtures of Argon (Ar), Carbon Tetrafluoride (CF4), and Sulfur...Etching of Barium Strontium Titanate Films Using Mixtures of Argon (Ar), Carbon Tetrafluoride (CF4), and Sulfur Hexafluoride (SF6) Samuel G...Study on Reactive Ion Etching of Barium Strontium Titanate Films Using Mixtures of Argon (Ar), Carbon Tetrafluoride (CF4), and Sulfur Hexafluoride

  13. [Platinum compounds: metabolism, toxicity and supportive strategies].

    Science.gov (United States)

    Lipp, H P; Hartmann, J T

    2005-02-09

    Although the leading platinum compounds, cisplatin, carboplatin, and oxaliplatin, share some structural similarities, there are marked differences between them in therapeutic uses, pharmacokinetics, and adverse effects profiles. Compared with cisplatin, carboplatin has inferior efficacy in germ-cell tumors, head and neck cancers, and bladder and esophageal carcinomas, whereas the two drugs appear to have comparable efficacy in ovarian cancer, extensive small-cell lung cancers (SCLC), and advanced non-small-cell lung cancers (NSCLC). Oxaliplatin belongs to the group of diaminocyclohexane (DACH) platinum compounds. It is the first platinum-based drug that has marked efficacy in colorectal cancer when given in combination with 5-fluorouracil and folinic acid. Nedaplatin has been registered in Japan, whereas other derivatives, like JM216 (which is the only orally available platinum derivative), ZD0473, BBR3464, and SPI-77 (a liposomal formulation of cisplatin), are still under investigation. The adverse effects of platinum compounds are reviewed together with possible prevention strategies.

  14. Bis-NHC chelate complexes of nickel(0) and platinum(0).

    Science.gov (United States)

    Brendel, Matthias; Braun, Carolin; Rominger, Frank; Hofmann, Peter

    2014-08-11

    For a long time d(10)-ML2 fragments have been known for their potential to activate unreactive bonds by oxidative addition. In the development of more active species, two approaches have proven successful: the use of strong σ-donating ligands leading to electron-rich metal centers and the employment of chelating ligands resulting in a bent coordination geometry. Combining these two strategies, we synthesized bis-NHC chelate complexes of nickel(0) and platinum(0). Bis(1,5-cyclooctadiene)nickel(0) and -platinum(0) react with bisimidazolium salts, deprotonated in situ at room temperature, to yield tetrahedral or trigonal-planar bis-NHC chelate olefin complexes. The synthesis and characterization of these complexes as well as a first example of C-C bond activation with these systems are reported. Due to the enforced cis arrangement of two NHCs, these compounds should open interesting perspectives for bond-activation chemistry and catalysis.

  15. Extremely Nonlinear Optics Using Shaped Pulses Spectrally Broadened in an Argon- or Sulfur Hexafluoride-Filled Hollow-Core Fiber

    Directory of Open Access Journals (Sweden)

    Andreas Hoffmann

    2015-11-01

    Full Text Available In this contribution we present a comparison of the performance of spectrally broadened ultrashort pulses using a hollow-core fiber either filled with argon or sulfur hexafluoride (SF6 for demanding pulse-shaping experiments. The benefits of both gases for pulse-shaping are studied in the highly nonlinear process of high-harmonic generation. In this setup, temporally shaping the driving laser pulse leads to spectrally shaping of the output extreme ultraviolet (XUV spectrum, where total yield and spectral selectivity in the XUV are the targets of the optimization approach. The effect of using sulfur hexafluoride for pulse-shaping the XUV yield can be doubled compared to pulse compression and pulse-shaping using argon and the spectral range for selective optimization of a single harmonic can be extended. The obtained results are of interest for extending the range of ultrafast science applications drawing on tailored XUV fields.

  16. A Course in Transport Phenomena in Multicomponent, Multiphase, Reacting Systems.

    Science.gov (United States)

    Carbonell, R. G.; Whitaker, S.

    1978-01-01

    This course concentrates on a rigorous development of the multicomponent transport equations, boundary conditions at phase interfaces, and volume-averaged transport equations for multiphase reacting systems. (BB)

  17. Extremely Nonlinear Optics Using Shaped Pulses Spectrally Broadened in an Argon- or Sulfur Hexafluoride-Filled Hollow-Core Fiber

    OpenAIRE

    Andreas Hoffmann; Michael Zürch; Christian Spielmann

    2015-01-01

    In this contribution we present a comparison of the performance of spectrally broadened ultrashort pulses using a hollow-core fiber either filled with argon or sulfur hexafluoride (SF6) for demanding pulse-shaping experiments. The benefits of both gases for pulse-shaping are studied in the highly nonlinear process of high-harmonic generation. In this setup, temporally shaping the driving laser pulse leads to spectrally shaping of the output extreme ultraviolet (XUV) spectrum, where total yie...

  18. Emission characteristics of plasma of a transverse volume discharge in mixtures of helium, argon, and krypton with sulfur hexafluoride

    Science.gov (United States)

    Shuaibov, A. K.; Shevera, I. V.; Sabov, I. I.; Gomoki, Z. T.

    2007-03-01

    The emission characteristics of the plasma of repetitively pulsed spontaneous UV-VUV radiation sources on the basis of ArF* (193 nm) and KrF* (249 nm) molecules, and the products of decomposition of sulfur hexafluoride molecules pumped by a transverse volume discharge in a mixture of inert gases with sulfur hexafluoride molecules have been investigated. The discharge emission spectra in the range of 190 780 nm at the low-current and high-current stages of the transverse discharge, the time characteristics of the voltage across the electrodes, the pump current, and the emission of excimer molecules and the products of decomposition of sulfur hexafluoride have been studied. It is shown that, in the gas-static operation mode of the radiator at the number of discharge pulses smaller than 103, the 193-nm ArF* and 249-nm KrF* bands are main in the emission spectrum. Upon further operation of the radiator, a spectral continuum is formed on the basis of sulfur molecular bands in the range 260 550 nm.

  19. Measurements of Non-reacting and Reacting Flow Fields of a Liquid Swirl Flame Burner

    Institute of Scientific and Technical Information of China (English)

    CHONG Cheng Tung; HOCHGREB Simone

    2015-01-01

    The understanding of the liquid fuel spray and flow field characteristics inside a combustor is crucial for designing a fuel efficient and low emission device. Characterisation of the flow field of a model gas turbine liquid swirl burner is performed by using a 2-D particle imaging velocimetry(PIV) system. The flow field pattern of an axial flow burner with a fixed swirl intensity is compared under confined and unconfined conditions, i.e., with and without the combustor wall. The effect of temperature on the main swirling air flow is investigated under open and non-reacting conditions. The result shows that axial and radial velocities increase as a result of decreased flow density and increased flow volume. The flow field of the main swirling flow with liquid fuel spray injection is compared to non-spray swirling flow. Introduction of liquid fuel spray changes the swirl air flow field at the burner outlet, where the radial velocity components increase for both open and confined environment. Under reacting condition, the enclosure generates a corner recirculation zone that intensifies the strength of radial velocity. The reverse flow and corner recirculation zone assists in stabilizing the flame by preheating the reactants. The flow field data can be used as validation target for swirl combustion modelling.

  20. Surfactant gel adsorption of platinum(II), (IV) and palladium(II) as chloro-complexes and kinetic separation of palladium from platinum using EDTA.

    Science.gov (United States)

    Murakami, Yoshiko; Hiraiwa, Kaoru; Sasaki, Yoshiaki; Fujiwara, Isamu; Tagashira, Shoji

    2007-09-01

    A micellar solution of cetylpyridinium chloride (CPC) can separate into two phases due to a temperature change or to the addition of salts. Platinum(II), (IV) and palladium(II) reacted with chloride ions to form stable anionic complexes of PtCl4(2-), PtCl6(2-) and PdCl4(2-), respectively, and were adsorbed onto the CPC gel phase. The CPC phase plays the role of an ion-exchange adsorbent for the anionic complexes. By such a procedure, the precious metals of platinum and palladium could be separated from base metals such as copper, zinc and iron. The kinetic separation was performed by a ligand exchange reaction of the palladium(II) chloro-complex with EDTA at 60 degrees C. The anionic palladium(II)-EDTA complex could not bind the opposite charged CP+ and was desorbed from the CPC phase. In the aqueous phase, the recovery of palladium(II) by the double-desorption was 101.1 +/- 1.2%. The platinum(II) and (IV) chloro-complexes were stable for at least 30 min and remained in the CPC phase.

  1. Characterization of electrochemically modified polycrystalline platinum surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Krebs, L.C.; Ishida, Takanobu.

    1991-12-01

    The characterization of electrochemically modified polycrystalline platinum surfaces has been accomplished through the use of four major electrochemical techniques. These were chronoamperometry, chronopotentiommetry, cyclic voltammetry, and linear sweep voltammetry. A systematic study on the under-potential deposition of several transition metals has been performed. The most interesting of these were: Ag, Cu, Cd, and Pb. It was determined, by subjecting the platinum electrode surface to a single potential scan between {minus}0.24 and +1.25 V{sub SCE} while stirring the solution, that the electrocatalytic activity would be regenerated. As a consequence of this study, a much simpler method for producing ultra high purity water from acidic permanganate has been developed. This method results in water that surpasses the water produced by pyrocatalytic distillation. It has also been seen that the wettability of polycrystalline platinum surfaces is greatly dependent on the quantity of oxide present. Oxide-free platinum is hydrophobic and gives a contact angle in the range of 55 to 62 degrees. We have also modified polycrystalline platinum surface with the electrically conducting polymer poly-{rho}-phenylene. This polymer is very stable in dilute sulfuric acid solutions, even under applied oxidative potentials. It is also highly resistant to electrochemical hydrogenation. The wettability of the polymer modified platinum surface is severely dependent on the choice of supporting electrolyte chosen for the electrochemical polymerization. Tetraethylammonium tetrafluoroborate produces a film that is as hydrophobic as Teflon, whereas tetraethylammonium perchlorate produces a film that is more hydrophilic than oxide-free platinum.

  2. Preconceptual design studies and cost data of depleted uranium hexafluoride conversion plants

    Energy Technology Data Exchange (ETDEWEB)

    Jones, E

    1999-07-26

    One of the more important legacies left with the Department of Energy (DOE) after the privatization of the United States Enrichment Corporation is the large inventory of depleted uranium hexafluoride (DUF6). The DOE Office of Nuclear Energy, Science and Technology (NE) is responsible for the long-term management of some 700,000 metric tons of DUF6 stored at the sites of the two gaseous diffusion plants located at Paducah, Kentucky and Portsmouth, Ohio, and at the East Tennessee Technology Park in Oak Ridge, Tennessee. The DUF6 management program resides in NE's Office of Depleted Uranium Hexafluoride Management. The current DUF6 program has largely focused on the ongoing maintenance of the cylinders containing DUF6. However, the long-term management and eventual disposition of DUF6 is the subject of a Programmatic Environmental Impact Statement (PEIS) and Public Law 105-204. The first step for future use or disposition is to convert the material, which requires construction and long-term operation of one or more conversion plants. To help inform the DUF6 program's planning activities, it was necessary to perform design and cost studies of likely DUF6 conversion plants at the preconceptual level, beyond the PEIS considerations but not as detailed as required for conceptual designs of actual plants. This report contains the final results from such a preconceptual design study project. In this fast track, three month effort, Lawrence Livermore National Laboratory and Bechtel National Incorporated developed and evaluated seven different preconceptual design cases for a single plant. The preconceptual design, schedules, costs, and issues associated with specific DUF6 conversion approaches, operating periods, and ownership options were evaluated based on criteria established by DOE. The single-plant conversion options studied were similar to the dry-conversion process alternatives from the PEIS. For each of the seven cases considered, this report contains

  3. A Framework for the Modelling of Biphasic Reacting Systems

    DEFF Research Database (Denmark)

    Anantpinijwatna, Amata; Sin, Gürkan; O’Connell, John P.

    2014-01-01

    Biphasic reacting systems have a broad application range from organic reactions in pharmaceutical and agro-bio industries to CO 2 capture. However, mathematical modelling of biphasic reacting systems is a formidable challenge due to many phenomena underlying the process such as chemical equilibri...... systems: a PTC-based reaction system and pseudo-PTC system....

  4. SYNTHESIS AND CATALYTIC HYDROSILYLATION PROPERTY OF POLYSILOXANE-SUPPORTED MERCAPTOSELENAETHER PLATINUM OR RHODIUM COMPLEX

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Silica-bound mercaptoselenaether-containing silsesquioxane and its platinum or rhodium complex were synthesized from γ-(2,3-epithiopropyl) propyltrimethoxysilane via ring-opening reaction with bis(2-hydroxyethyl) selenide, followed by hydrolysis and immobilization on fumed silica, and then reacting with potassium chloroplatinite or rhodium chloride in acetone under nitrogen atmosphere. It was found that two noble metal complexes can catalyze the hydrosilylation of olefins with triethoxysilane effectively. The influences of temperature, the amount of complex used, the nature of olefin on catalytic activity were investigated.

  5. Room temperature synthesis of colloidal platinum nanoparticles

    Indian Academy of Sciences (India)

    G Sarala Devi; V J Rao

    2000-12-01

    Efficient preparation of stable dispersions of platinum nanoparticles from platinous chloride (K2PtCl4) was achieved by simultaneous addition of capping polymer material. The size of platinum nanoparticles was controlled by changing the ratio of concentration of capping polymer material to the concentration of platinum cation used. The morphology of colloidal particles were studied by means of UV-visible spectrophotometry and transmission electron microscopy (TEM). Particle size increased with low reagent concentration. The change in absorption spectra with the particle size was observed, i.e. blue shift attributed to decrease in particle size.

  6. Stabilizing platinum in phosphoric acid fuel cells

    Science.gov (United States)

    Remick, R. J.

    1981-10-01

    A carbon substrate for use in fabricating phosphoric acid fuel cell cathodes was modified by catalytic oxidation to stabilize the platinum catalyst by retarding the sintering of small platinum crystallites. Results of 100-hour operational tests confirmed that the rate of platinum surface area loss observed on catalytically oxidized supports was less than that observed with unmodified supports of the same starting material. Fuel cell electrodes fabricated from Vulcan XC-72R, which was modified by catalytic in a nitric oxide atmosphere, produced low platium sintering rates and high activity for the reduction of oxygen in the phosphoric acid environment.

  7. Antitumor effect of arabinogalactan and platinum complex.

    Science.gov (United States)

    Starkov, A K; Zamay, T N; Savchenko, A A; Ingevatkin, E V; Titova, N M; Kolovskaya, O S; Luzan, N A; Silkin, P P; Kuznetsova, S A

    2016-03-01

    The article presents the results of investigation of antitumor properties of platinum-arabinogalactan complex. We showed the ability of the complex to inhibit the growth of Ehrlich ascites tumor cells. It is found that the distribution of the platinum-arabinogalactan complex is not specific only for tumor cells in mice. The complex was found in all tissues and organs examined (ascites cells, embryonic cells, kidney, and liver). The mechanism of action of the arabinogalactan-platinum complex may be similar to cisplatin as the complex is able to accumulate in tumor cells.

  8. Mechanism of Platinum Derivatives Induced Kidney Injury

    Directory of Open Access Journals (Sweden)

    Feifei YAN

    2015-09-01

    Full Text Available Platinum derivatives are the most widely used chemotherapeutic agents to treat solid tumors including ovarian, head and neck, and testicular germ cell tumors, lung cancer, and colorectal cancer. Two major problems exist, however, in the clinic use of platinum derivatives. One is the development of tumor resistance to the drug during therapy, leading to treatment failure. The other is the drug’s toxicity such as the cisplatin’s nephrotoxicity, which limits the dose that can be administered. This paper describes the mechanism of platinum derivatives induced kidney injury.

  9. Uranium hexafluoride liquid thermal expansion, elusive eutectic with hydrogen fluoride, and very first production using chlorine trifluoride

    Energy Technology Data Exchange (ETDEWEB)

    Rutledge, G.P. [Central Environmental, Inc., Anchorage, AK (United States)

    1991-12-31

    Three unusual incidents and case histories involving uranium hexafluoride in the enrichment facilities of the USA in the late 1940`s and early 1950`s are presented. The history of the measurements of the thermal expansion of liquids containing fluorine atoms within the molecule is reviewed with special emphasis upon uranium hexafluoride. A comparison is made between fluorinated esters, fluorocarbons, and uranium hexafluoride. The quantitative relationship between the thermal expansion coefficient, a, of liquids and the critical temperature, T{sub c} is presented. Uranium hexafluoride has an a that is very high in a temperature range that is used by laboratory and production workers - much higher than any other liquid measured. This physical property of UF{sub 6} has resulted in accidents involving filling the UF{sub 6} containers too full and then heating with a resulting rupture of the container. Such an incident at a uranium gaseous diffusion plant is presented. Production workers seldom {open_quotes}see{close_quotes} uranium hexafluoride. The movement of UF{sub 6} from one container to another is usually trailed by weight, not sight. Even laboratory scientists seldom {open_quotes}see{close_quotes} solid or liquid UF{sub 6} and this can be a problem at times. This inability to {open_quotes}see{close_quotes} the UF{sub 6}-HF mixtures in the 61.2{degrees}C to 101{degrees}C temperature range caused a delay in the understanding of the phase diagram of UF{sub 6}-HF which has a liquid - liquid immiscible region that made the eutectic composition somewhat elusive. Transparent fluorothene tubes solved the problem both for the UF{sub 6}-HF phase diagram as well as the UF{sub 6}-HF-CIF{sub 3} phase diagram with a miscibility gap starting at 53{degrees}C. The historical background leading to the first use of CIF{sub 3} to produce UF{sub 6} in both the laboratory and plant at K-25 is presented.

  10. SYNTHESIS OF DI(ETHYLMERCAPTOETHYL) AMINO GROUP—CONTAINING POLYSESQUISILOXANE PLATINUM COMPLEX AND ITS CATALYSIS IN HYDROSIL YLATION OF OLEFINS WITH TRIETHOXYSILANE

    Institute of Scientific and Technical Information of China (English)

    CHENYuanyin; HUXubo; 等

    1992-01-01

    Three new polysesquisiloxane-bound platinum complexes were synthesized via hydrolysis of N,N-di(β-ethylmercaptoethyl)γ-(triethoxysilyl)propylamine or cohydrolysis of the monomer with dodecyltriethoxysilane or with phenylpropylthiethoxysilane and immobilixation on fumed silica,followed by reacting with potassium platinite in acetone under argon atmosphere.The platinum complexes exhibited high catalytic activity for the hydrosilylation of olefins by triethoxysilane. The effects of temperature and the amount of complex on the catalytic activity,as well as the recovery and reusability of the catalysts were investigated.

  11. The variability of methane, nitrous oxide and sulfur hexafluoride in Northeast India

    Directory of Open Access Journals (Sweden)

    A. L. Ganesan

    2013-11-01

    Full Text Available High-frequency atmospheric measurements of methane (CH4, nitrous oxide (N2O and sulfur hexafluoride (SF6 from Darjeeling, India are presented from December 2011 (CH4/March 2012 (N2O and SF6 through February 2013. These measurements were made on a gas chromatograph equipped with a flame ionization detector and electron capture detector, and were calibrated on the Tohoku University, the Scripps Institution of Oceanography (SIO-98 and SIO-2005 scales for CH4, N2O and SF6, respectively. The observations show large variability and frequent pollution events in CH4 and N2O mole fractions, suggesting significant sources in the regions sampled by Darjeeling throughout the year. By contrast, SF6 mole fractions show little variability and only occasional pollution episodes, likely due to weak sources in the region. Simulations using the Numerical Atmospheric dispersion Modelling Environment (NAME particle dispersion model suggest that many of the enhancements in the three gases result from the transport of pollutants from the densely populated Indo-Gangetic Plains of India to Darjeeling. The meteorology of the region varies considerably throughout the year from Himalayan flows in the winter to the strong south Asian summer monsoon. The model is consistent in simulating a diurnal cycle in CH4 and N2O mole fractions that is present during the winter but absent in the summer and suggests that the signals measured at Darjeeling are dominated by large-scale (~100 km flows rather than local (<10 km flows.

  12. Dry uranium tetrafluoride process preparation using the uranium hexafluoride reconversion process effluents

    Energy Technology Data Exchange (ETDEWEB)

    Silva Neto, J.B.; Urano de Carvalho, E.F.; Oliveira, F.B.V. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mails: jbsneto@ipen.br; elitaucf@ipen.br; fabio@ipen.br; Riella, H.G. [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil)]. E-mail: riella@enq.ufsc.br

    2007-07-01

    It is a well known fact that the use of uranium tetrafluoride allows flexibility in the production of uranium silicide and uranium oxide fuel. To its obtention there are two conventional routes, the one which reduces uranium from the UF{sub 6} hydrolysis solution with stannous chloride, and the hydrofluorination of a solid uranium dioxide. In this work we are introducing a third and a dry way route, mainly utilized to the recovery of uranium from the liquid effluents generated in the uranium hexafluoride reconversion process, at IPEN/CNEN-SP. Working in the liquid phase, this route comprises the recuperation of ammonium fluoride by NH{sub 4}HF{sub 2} precipitation. Working with the solid residues, the crystallized bifluoride is added to the solid UO{sub 2}, which comes from the U miniplates recovery, also to its conversion in a solid state reaction, to obtain UF{sub 4}. That returns to the process of metallic uranium production unity to the U{sub 3}Si{sub 2} obtention. This fuel is considered in IPEN-CNEN/SP as the high density fuel phase for IEA-R1m reactor, which will replace the former low density U{sub 3}O{sub 8}-Al fuel. (author)

  13. BR1: A new ultrasonographic contrast agent based on sulfur hexafluoride-filled microbubbles

    Energy Technology Data Exchange (ETDEWEB)

    Scheider, M.; Arditi, M.; Barrau, M.B.

    1995-08-01

    Rationale and objectives. The basic characteristics of BR1, a novel echo contrast agent based on stabilized sulfur hexafluoride (SF{sub 6}) microbubbles have been evaluated. Methods. The authors determined the physicochemical properties (bubble concentration, bubble size distribution, resistance to pressure, and stability) and the acoustic properties (backscatter and attenuation coefficients) of BR1. The diagnostic value of BR1 was evaluated further in minipigs. Left heart images were recorded before and after injection of different doses of BR1. Results. BR1 is formulated as a lyophilized products, which after addition of saline, provides a suspension containing 2 X 10{sup 8} SF{sub 6} microbubbles/mL with a number mean diameter of 2.5 {mu}m. More than 90% of the bubbles are below 8 {mu}m. The use of SF{sub 6} rather than air provides an improved resistance to pressure increases such as the ones occuring in the left heart during systole. After reconstitution, the echogenicity and the bubble characteristics are unchanged for more than 8 hours. The high echogenicity remains almost constant over the entire medical frequency range (1-10 MH{sub Z}). BR1 injections in animals resulted in a homogenous, dose-dependent opacification of the left heart. Conclusions. Considering its high echogenicity, outstanding stability, and resistance to pressure changes, BR1 is a very promising ultrasound contrast agent. 14 refs., 8 figs., 3 tabs.

  14. Highlighting cavities in proteins by NMR using sulfur hexafluoride as a spy molecule.

    Science.gov (United States)

    Fusaro, Luca; Locci, Emanuela; Lai, Adolfo; Luhmer, Michel

    2010-03-11

    Cavities in proteins can be studied experimentally by using some detectable atoms, such as xenon, or molecules which act as reporter, such as a spy. The interest of sulfur hexafluoride (SF(6)) for probing hydrophobic cavities by solution-state NMR is investigated. The wheat nonspecific lipid transfer protein (LTP) was selected as a model system for this purpose. The binding of SF(6) is straightforwardly detected by the (19)F chemical shift, line width, or longitudinal relaxation time measurements, which can be carried out at low SF(6) concentration without interference from resonances of the protein. Most interestingly, the binding of SF(6) gives rise to selective intermolecular (1)H{(19)F} heteronuclear Overhauser effects (HOEs). Molecular dynamics simulation and NMR spectrum modeling show that the experimental HOESY spectra are consistent with (1)H{(19)F} HOEs arising from SF(6) in the cavity of LTP. SF(6) is found to be an advantageous alternative to hyperpolarized (129)Xe and small organic compounds for probing cavities in proteins by solution-state NMR.

  15. A search for the sulphur hexafluoride cation with intense, few cycle laser pulses.

    Science.gov (United States)

    Dota, Krithika; Dharmadhikari, Aditya K; Dharmadhikari, Jayashree A; Patra, Kaustuv; Tiwari, Ashwani K; Mathur, Deepak

    2013-11-21

    It is well established that upon ionization of sulphur hexafluoride, the SF6(+) ion is never observed in mass spectra. Recent work with ultrashort intense laser pulses has offered indications that when strong optical field are used, the resulting "bond hardening" can induce changes in the potential energy surfaces of molecular cations such that molecular ions that are normally unstable may, indeed, become metastable enough to enable their detection by mass spectrometry. Do intense, ultrashort laser pulses permit formation of SF6(+)? We have utilized intense pulses of 5 fs, 11 fs, and 22 fs to explore this possibility. Our results are negative: no evidence is discovered for SF6(+). However, multiply charged sulphur and fluorine ions from highly charged SF6(q+) ions are observed that enable us to resolve the controversy regarding the kinetic energy release accompanying formation of F(+) fragment ions. Quantum chemical computations of field-distorted potential energy curves of SF6 and its molecular ion enable us to rationalize our non-observation of SF6(+). Our findings have implications for high harmonic generation from SF6 in the few-cycle regime.

  16. Size dependence of the bandgap of plasma synthesized silicon nanoparticles through direct introduction of sulfur hexafluoride

    Energy Technology Data Exchange (ETDEWEB)

    Theingi, S.; Guan, T. Y.; Klafehn, G.; Taylor, P. C.; Lusk, M. T.; Collins, R. T., E-mail: rtcollin@mines.edu [Department of Physics, Colorado School of Mines, Golden, Colorado 80401 (United States); Renewable Energy Materials Research Science and Engineering Center, Colorado School of Mines, Golden, Colorado 80401 (United States); Kendrick, C. [Department of Physics, Colorado School of Mines, Golden, Colorado 80401 (United States); Renewable Energy Materials Research Science and Engineering Center, Colorado School of Mines, Golden, Colorado 80401 (United States); Electrical and Computer Engineering, Michigan Technological University, Houghton, Michigan 49931 (United States); Gorman, B. P. [Metallurgical and Materials Engineering, Colorado School of Mines, Golden, Colorado 80401 (United States); Stradins, P. [Renewable Energy Materials Research Science and Engineering Center, Colorado School of Mines, Golden, Colorado 80401 (United States); National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)

    2015-10-19

    Developing silicon nanoparticle (SiNP) synthesis techniques that allow for straightforward control of nanoparticle size and associated optical properties is critical to potential applications of these materials. In addition, it is, in general, hard to probe the absorption threshold in these materials due to silicon's low absorption coefficient. In this study, size is controlled through direct introduction of sulfur hexafluoride (SF{sub 6}) into the dilute silane precursor of plasma synthesized SiNPs. Size reduction by nearly a factor of two with high crystallinity independent of size is demonstrated. The optical absorption spectra of the SiNPs in the vicinity of the bandgap are measured using photothermal deflection spectroscopy. Bandgap as a function of size is extracted taking into account the polydispersity of the samples. A systematic blue shift in absorption edge due to quantum confinement in the SiNPs is observed with increasing flow of SF{sub 6}. Photoluminescence (PL) spectra show a similar blue shift with size. However, a ∼300 meV difference in energy between emission and absorption for all sizes suggests that PL emission involves a defect related process. This shows that, while PL may allow size-induced shifts in the bandgap of SiNPs to be monitored, it cannot be relied on to give an accurate value for the bandgap as a function of size.

  17. Size Dependence of the Bandgap of Plasma Synthesized Silicon Nanoparticles Through Direct Introduction of Sulfur Hexafluoride

    Energy Technology Data Exchange (ETDEWEB)

    Theingi, S.; Guan, T. Y.; Kendrick, C.; Klafehn, G.; Gorman, B. P.; Taylor, P. C.; Lusk, M. T.; Stradins, Pauls; Collins, R. T.

    2015-10-19

    Developing silicon nanoparticle (SiNP) synthesis techniques that allow for straightforward control of nanoparticle size and associated optical properties is critical to potential applications of these materials. In addition, it is, in general, hard to probe the absorption threshold in these materials due to silicon's low absorption coefficient. In this study, size is controlled through direct introduction of sulfur hexafluoride (SF6) into the dilute silane precursor of plasma synthesized SiNPs. Size reduction by nearly a factor of two with high crystallinity independent of size is demonstrated. Optical absorption spectra of the SiNPs in the vicinity of the bandgap are measured using photothermal deflection spectroscopy. Bandgap as a function of size is extracted taking into account the polydispersity of the samples. A systematic blue shift inabsorption edge due to quantum confinement in the SiNPs is observed with increasing flow of SF6. Photoluminescence (PL) spectra show a similar blue shift with size. However, a ~300 meV difference in energy between emission and absorption for all sizes suggests that PL emission involves a defect related process. While PL may allow size-induced shifts in the bandgap of SiNPs to be monitored, it cannot be relied on to give an accurate value for the bandgap as a function of size.

  18. Platinum-Resistor Differential Temperature Sensor

    Science.gov (United States)

    Kolbly, R. B.; Britcliffe, M. J.

    1985-01-01

    Platinum resistance elements used in bridge circuit for measuring temperature difference between two flowing liquids. Temperature errors with circuit are less than 0.01 degrees C over range of 100 degrees C.

  19. Fate of platinum metals in the environment.

    Science.gov (United States)

    Pawlak, Justyna; Łodyga-Chruścińska, Elżbieta; Chrustowicz, Jakub

    2014-07-01

    For many years now automotive exhaust catalysts have been used to reduce the significant amounts of harmful chemical substances generated by car engines, such as carbon monoxide, nitrogen oxides, and aromatic hydrocarbons. Although they considerably decrease environmental contamination with the above-mentioned compounds, it is known that catalysts contribute to the environmental load of platinum metals (essential components of catalysts), which are released with exhaust fumes. Contamination with platinum metals stems mainly from automotive exhaust converters, but other major sources also exist. Since platinum group elements (PGEs): platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru) and iridium (Ir) seem to spread in the environment and accumulate in living organisms, they may pose a threat to animals and humans. This paper discusses the modes and forms of PGE emission as well as their impact on the environment and living organisms.

  20. VB Platinum Tile & Carpet, Inc. Information Sheet

    Science.gov (United States)

    VB Platinum Tile & Carpet, Inc. (the Company) is located in Bristow, Virginia. The settlement involves renovation activities conducted at a property constructed prior to 1978, located in Washington, DC.

  1. Stabilizing platinum in phosphoric acid fuel cells

    Science.gov (United States)

    Remick, R. J.

    1982-01-01

    Platinum sintering on phosphoric acid fuel cell cathodes is discussed. The cathode of the phosphoric acid fuel cell uses a high surface area platinum catalyst dispersed on a conductive carbon support to minimize both cathode polarization and fabrication costs. During operation, however, the active surface area of these electrodes decreases, which in turn leads to decreased cell performance. This loss of active surface area is a major factor in the degradation of fuel cell performance over time.

  2. Species Source Term Mapping for Reacting Flow CFD Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Simulations of reacting flow in applications such as scramjet engines are currently limited in their utility or accuracy by the chemistry sub-models employed....

  3. Simultaneous Temperature and Velocity Diagnostic for Reacting Flows Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A diagnostic technique is proposed for measuring temperature and velocity simultaneously in a high temperature reacting flow for aiding research in propulsion. The...

  4. Diamond tool machining of materials which react with diamond

    Science.gov (United States)

    Lundin, Ralph L.; Stewart, Delbert D.; Evans, Christopher J.

    1992-01-01

    Apparatus for the diamond machining of materials which detrimentally react with diamond cutting tools in which the cutting tool and the workpiece are chilled to very low temperatures. This chilling halts or retards the chemical reaction between the workpiece and the diamond cutting tool so that wear rates of the diamond tool on previously detrimental materials are comparable with the diamond turning of materials which do not react with diamond.

  5. Platinum in Earth surface environments

    Science.gov (United States)

    Reith, F.; Campbell, S. G.; Ball, A. S.; Pring, A.; Southam, G.

    2014-04-01

    Platinum (Pt) is a rare precious metal that is a strategic commodity for industries in many countries. The demand for Pt has more than doubled in the last 30 years due to its role in the catalytic conversion of CO, hydrocarbons and NOx in modern automobiles. To explore for new Pt deposits, process ores and deal with ecotoxicological effects of Pt mining and usage, the fundamental processes and pathways of Pt dispersion and re-concentration in surface environments need to be understood. Hence, the aim of this review is to develop a synergistic model for the cycling of Pt in Earth surface environments. This is achieved by integrating the geological/(biogeo)chemical literature, which focuses on naturally occurring Pt mobility around ore deposits, with the environmental/ecotoxicological literature dealing with anthropogenic Pt dispersion. In Pt deposits, Pt occurs as sulfide-, telluride- and arsenide, native metal and alloyed to other PGEs and iron (Fe). Increased mining and utilization of Pt combined with the burning of fossil fuels have led to the dispersion of Pt-containing nano- and micro-particles. Hence, soils and sediments in industrialized areas, urban environments and along major roads are now commonly Pt enriched. Platinum minerals, nuggets and anthropogenic particles are transformed by physical and (bio)geochemical processes. Complexation of Pt ions with chloride, thiosulfate, ammonium, cyanide, low- and high molecular weight organic acids (LMWOAs and HMWOAs) and siderophores can facilitate Pt mobilization. Iron-oxides, clays, organic matter and (micro)biota are known to sequester Pt-complexes and -particles. Microbes and plants are capable of bioaccumulating and reductively precipitating mobile Pt complexes. Bioaccumulation can lead to toxic effects on plants and animals, including humans. (Bio)mineralization in organic matter-rich sediments can lead to the formation of secondary Pt particles and -grains. Ultimately, Pt is enriched in oceanic sediments

  6. Comparison of 20% sulfur hexafluoride with air for intraocular tamponade in Descemet membrane endothelial keratoplasty (DMEK

    Directory of Open Access Journals (Sweden)

    Benjamin Botsford

    Full Text Available ABSTRACT Purpose: To compare the effect of 20% sulfur hexafluoride (SF6 with that of air on graft detachment rates for intraocular tamponade in Descemet membrane endothelial keratoplasty (DMEK. Methods: Forty-two eyes of patients who underwent DMEK by a single surgeon (A.S.J. at Wilmer Eye Institute between January 2012 and 2014 were identified; 21 received air for intraocular tamponade and the next consecutive 21 received SF6. The main outcome measure was the graft detachment rate; univariate and multivariate analyses were performed. Results: The graft detachment rate was 67% in the air group and 19% in the SF6 group (p<0.05. No complete graft detachments occurred, and all partial detachments underwent intervention with injection of intraocular air. The percentages of eyes with 20/25 or better vision were not different between the groups (67% vs. 71%. Univariate analysis showed significantly higher detachment rates with air tamponade (OR, 8.50; p<0.005 and larger donor graft size (OR, 14.96; p<0.05. Multivariate analysis with gas but not graft size included showed that gas was an independent statistically significant predictor of outcome (OR, 6.65; p<0.05. When graft size was included as a covariate, gas was no longer a statistically significant predictor of detachment but maintained OR of 7.81 (p=0.063 similar to the results of univariate and multivariate analyses without graft size. Conclusion: In comparison with air, graft detachment rates for intraocular tamponade in DMEK were significantly reduced by 20% SF6.

  7. Containment and storage of uranium hexafluoride at US Department of Energy uranium enrichment plants

    Energy Technology Data Exchange (ETDEWEB)

    Barlow, C.R.; Alderson, J.H.; Blue, S.C.; Boelens, R.A.; Conkel, M.E.; Dorning, R.E.; Ecklund, C.D.; Halicks, W.G.; Henson, H.M.; Newman, V.S.; Philpot, H.E.; Taylor, M.S.; Vournazos, J.P. [Oak Ridge K-25 Site, TN (United States). UEO Enrichment Technical Operations Div.; Russell, J.R. [USDOE Oak Ridge Field Office, TN (United States); Pryor, W.A. [PAI Corp., Oak Ridge, TN (United States); Ziehlke, K.T. [MJB Technical Associates (United States)

    1992-07-01

    Isotopically depleted UF{sub 6} (uranium hexafluoride) accumulates at a rate five to ten times greater than the enriched product and is stored in steel vessels at the enrichment plant sites. There are approximately 55,000 large cylinders now in storage at Paducah, Kentucky; Portsmouth, Ohio; and Oak Ridge, Tennessee. Most of them contain a nominal 14 tons of depleted UF{sub 6}. Some of these cylinders have been in the unprotected outdoor storage environment for periods approaching 40 years. Storage experience, supplemented by limited corrosion data, suggests a service life of about 70 years under optimum conditions for the 48-in. diameter, 5/16-in.-wall pressure vessels (100 psi working pressure), using a conservative industry-established 1/4-in.-wall thickness as the service limit. In the past few years, however, factors other than atmospheric corrosion have become apparent that adversely affect the serviceability of small numbers of the storage containers and that indicate the need for a managed program to ensure maintenance ofcontainment integrity for all the cylinders in storage. The program includes periodic visual inspections of cylinders and storage yards with documentation for comparison with other inspections, a group of corrosion test programs to permit cylinder life forecasts, and identification of (and scheduling for remedial action) situations in which defects, due to handling damage or accelerated corrosion, can seriously shorten the storage life or compromise the containment integrity of individual cylinders. The program also includes rupture testing to assess the effects of certain classes of damage on overall cylinder strength, aswell as ongoing reviews of specifications, procedures, practices, and inspection results to effect improvements in handling safety, containment integrity, and storage life.

  8. Results of the remote sensing feasibility study for the uranium hexafluoride storage cylinder yard program

    Energy Technology Data Exchange (ETDEWEB)

    Balick, L.K.; Bowman, D.R. [Bechtel Nevada, Las Vegas, NV (United States). Remote Sensing Lab.; Bounds, J.H. [Los Alamos National Lab., NM (United States)] [and others

    1997-02-01

    The US DOE manages the safe storage of approximately 650,000 tons of depleted uranium hexafluoride remaining from the Cold War. This slightly radioactive, but chemically active, material is contained in more than 46,000 steel storage cylinders that are located at Oak Ridge, Tennessee; Paducah, Kentucky; and Portsmouth, Ohio. Some of the cylinders are more than 40 years old, and approximately 17,500 are considered problem cylinders because their physical integrity is questionable. These cylinders require an annual visual inspection. The remainder of the 46,000-plus cylinders must be visually inspected every four years. Currently, the cylinder inspection program is extremely labor intensive. Because these inspections are accomplished visually, they may not be effective in the early detection of leaking cylinders. The inspection program requires approximately 12--14 full-time-equivalent (FTE) employees. At the cost of approximately $125K per FTE, this translates to $1,500K per annum just for cylinder inspection. As part of the technology-development portion of the DOE Cylinder Management Program, the DOE Office of Facility Management requested the Remote Sensing Laboratory (RSL) to evaluate remote sensing techniques that have potential to increase the effectiveness of the inspection program and, at the same time, reduce inspection costs and personnel radiation exposure. During two site visits (March and May 1996) to the K-25 Site at Oak Ridge, TN, RSL personnel tested and characterized seven different operating systems believed to detect leakage, surface contamination, thickness and corrosion of cylinder walls, and general area contamination resulting from breached cylinders. The following techniques were used and their performances are discussed: Laser-induced fluorescent imaging; Long-range alpha detection; Neutron activation analysis; Differential gamma-ray attenuation; Compton scatterometry; Active infrared inspection; and Passive thermal infrared imaging.

  9. Blood oxygen saturation measured in the presence of a mixture of cyclopropane, sulfur hexafluoride, and ethane.

    Science.gov (United States)

    Forte, V A; Burse, R L; Cymerman, A

    1997-01-01

    Some anesthetic gases interfere with the determination of blood O2 values. We evaluated, for its potential for such interference, a gas mixture containing (v/v) approximately 70% ethane, 20% sulfur hexafluoride, and 10% cyclopropane, as is currently used in trace amounts to determine ventilation-perfusion (v/Q) ratios. Normal human blood samples were first tonometered with control gas mixtures containing (v/v): (1) 20.9% O2, 0.04% CO2; (2) 16.0% O2, 4.0% CO2; and (3) 9.9% O2, 7.8% CO2. A large quantity (20.9%) of the v/Q mixture was blended experimentally into the control mixture and the tonometry repeated. The entire experiment was then repeated substituting pure N2 for the v/Q mixture as a dilution control. O2 values were determined by three methods: (1) a polarographic electrode, ABL-300 (ABL); (2) a spectrophotometric method, Co-Oximeter (COOX); and (3) a galvanic cell, Lex-O2-Con (LEX). The v/Q gas mixture lowered significantly all measured LEX values by 2.5-3.6 saturation percent (sat%), but showed no effect, dilution or otherwise, on the O2 values determined by the COOX and ABL methods. The N2 dilution lowered the LEX values by an average of only 0.9 sat%; the ABL and the COOX were approximately 0.6 sat% lower. We therefore suggest that, if any of these O2 measurement methods are used in the presence of the v/Q mixture, baseline O2 values should be determined both before and after injection of the mixture into the bloodstream, prior to performing other experimental manipulations. The difference between the two values, if any, can then be used to interpret subsequent results.

  10. Sulfur hexafluoride (SF6) emissions in East Asia determined by inverse modeling

    Science.gov (United States)

    Fang, X.; Thompson, R. L.; Saito, T.; Yokouchi, Y.; Kim, J.; Li, S.; Kim, K. R.; Park, S.; Graziosi, F.; Stohl, A.

    2014-05-01

    Sulfur hexafluoride (SF6) has a global warming potential of around 22 800 over a 100-year time horizon and is one of the greenhouse gases regulated under the Kyoto Protocol. Around the year 2000 there was a reversal in the global SF6 emission trend, from a decreasing to an increasing trend, which was likely caused by increasing emissions in countries that are not obligated to report their annual emissions to the United Nations Framework Convention on Climate Change. In this study, SF6 emissions during the period 2006-2012 for all East Asian countries - including Mongolia, China, Taiwan, North Korea, South Korea and Japan - were determined by using inverse modeling and in situ atmospheric measurements. We found that the most important sources of uncertainty associated with these inversions are related to the choice of a priori emissions and their assumed uncertainty, the station network as well as the meteorological input data. Much lower uncertainties are due to seasonal variability in the emissions, inversion geometry and resolution, and the measurement calibration scale. Based on the results of these sensitivity tests, we estimate that the total SF6 emission in East Asia increased rapidly from 2404 ± 325 Mg yr-1 in 2006 to 3787 ± 512 Mg yr-1 in 2009 and stabilized thereafter. China contributed 60-72% to the total East Asian emission for the different years, followed by South Korea (8-16%), Japan (5-16%) and Taiwan (4-7%), while the contributions from North Korea and Mongolia together were less than 3% of the total. The per capita SF6 emissions are highest in South Korea and Taiwan, while the per capita emissions for China, North Korea and Japan are close to global average. During the period 2006-2012, emissions from China and from South Korea increased, while emissions from Taiwan and Japan decreased overall.

  11. Sulfur hexafluoride (SF6 emissions in East Asia determined by inverse modeling

    Directory of Open Access Journals (Sweden)

    X. Fang

    2013-08-01

    Full Text Available Sulfur hexafluoride (SF6 has a global warming potential of around 22 800 over a 100 yr time horizon and is one of the greenhouse gases regulated under the Kyoto Protocol. Around circa 2000 there was a reversal in the global SF6 emission trend, from a decreasing to an increasing trend, which was likely caused by increasing emissions in countries that are not obligated to report their annual emissions to the United Nations Framework Convention on Climate Change. In this study, SF6 emissions during the period 2006–2012 for all East Asian countries, including Mongolia, China, the Taiwan region, North Korea, South Korea and Japan, were determined by using inverse modeling and in-situ atmospheric measurements. We found that the most important sources of uncertainty associated with these inversions are related to the choice of a priori emissions and their assumed uncertainty, the station network as well as the meteorological input data. Much lower uncertainties are due to seasonal variability in the emissions, inversion geometry and resolution, and the measurement calibration scale. Based on the results of these sensitivity tests, we estimate that the total SF6 emission in East Asia increased rapidly from 2437 ± 329 Mg yr−1 in 2006 to 3787 ± 512 Mg yr−1 in 2009 and stabilized thereafter. China contributed 58–72 % to the total East Asian emission for the different years, followed by South Korea (9–19%, Japan (5–16% and the Taiwan region (4–7%, while the contributions from North Korea and Mongolia together were less than 3% of the total. The per-capita SF6 emissions are highest in South Korea and the Taiwan region, while the per-capita emissions for China, North Korea and Japan are close to global average. During the period 2006–2012, emissions from China increased rapidly and emissions from South Korea increased slightly, while emissions from the Taiwan region and Japan decreased overall.

  12. Implementation of the Sulfur Hexafluoride Technique in Costa Rica to Quantify Enteric Methane in Cattle

    Directory of Open Access Journals (Sweden)

    Johnny Montenegro Ballestero

    2016-12-01

    Full Text Available In order to implement, for the first time in Costa Rica, the sulfur hexafluoride (SF6 tracer technique to determine the enteric methane (CH4released by cattle consuming tropical forages, this study was carried out at the Universidad Tecnica Nacional, Atenas, from May to July 2013. This technique allows capturing and storing a sample of methane in a device placed over the animal. The implementation was done in two phases: confinement and grazing. In both phases, Jersey heifers were used. They were subjected to an adaptation phase prior to the collection of gas samples. Confinement diet consisted of transvala silopaca (Digitaria decumbens and Brachiaria brizantha. In the second phase B. decumbens was grazed. The three species had 35 days of regrowth without fertilization. The daily emission of methane per heifer in confinement was 147±7 g, and 17.3±1.1 g kg-1 DM consumed. During the grazing phase, heifers released 141±16 g of CH4 d-1, and 16.1±1.1 g of CH4 kg-1 DM of consumed grass was estimated. The emission factor (Ym: 4.9 ± 0.3% for the grazing phase was lower than that suggested by IPCC. It is concluded that this technique is suitable for use under similar conditions to those used in this research, and with the calculation of Ym it is possible to estimate with low uncertainty, the emission of enteric methane in cattle that should be used in the National Inventories Greenhouse Gases for the livestock sector in Costa Rica.

  13. [Performance evaluation of two N95 filtering-facepiece respirators on decomposition products of sulfur hexafluoride].

    Science.gov (United States)

    Zhu, X C; Lu, W; Nie, X Q; Zhou, M; Zhang, R B; Qin, S X; Chen, W H

    2016-05-20

    To assess the filtration efficiency of two N95 filtering-facepiece respirators (FFRs) for the decomposition products of sulfur hexafluoride (SF6). Two types of N95 FFRs (the particulate and the acid-proof respirators) were selected in this study. The decomposition products of SF6, including particles, hydrogen fluoride (HF) and sulfur dioxide (SO2) , were measured under experimental condition by using TSI PortaCount Plus, fluorine ion-selective electrodes and spectrophotometer separately. The filtration efficiency was then calculated and compared. Both two models of N95 respirators had lowest filtration efficiency larger than 95% for particles under airflow ranged from 10 to 95 L/min. When exposed to different concentrations of HF (low: 0.00~1.99 mg/m(3), middle: 2.00~3.99 mg/m(3), high: >4 mg/m(3)) , the acid-proof N95 respirator was more effective than the particulate respirator (P10.00 mg/m(3)) , the acid-proof respirator showed a high filtration efficiency within exposure to 1.5 hours: 95.73%, 98.67%, 98.14%, and 97.78%, respectively, when exposure duration extended to 4 hours, the filtration efficiency of the acid-proof respirator decreased to 91.97%, 82.28%, 70.12%, and 58.56%, respectively. Both the particulate and the acid-proof N95 FFRs met national standards on the particulate filtration efficiency. The acid-proof N95 respirator demonstrates to be more effective in filtering HF and SO2 than the particulate respirator. The filtration efficiency could decrease to an unsafe condition under longer exposure duration, timely replacement of respirator is recommended at the workplace.

  14. Bibliography of electron and photon cross sections with atoms and molecules published in the 20th century. Sulphur hexafluoride

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Makoto [Gaseous Electronics Institute, Nagoya, Aichi (Japan)

    2003-05-01

    A bibliography of original and review reports of experiments or theories of electron and photon cross sections and also electron swarm data are presented for atomic or molecular species with specified targets. These works covered 17 atoms and 51 molecules. The present bibliography is only for sulphur hexafluoride (SF{sub 6}). About 920 papers were compiled. A comprehensive author index is included. The bibliography covers the period 1934 through 2000 for SF{sub 6}. Finally, author's comments for SF{sub 6} electron collision cross section are given. (author)

  15. computer modeling ter modeling ter modeling of platinum reforming ...

    African Journals Online (AJOL)

    eobe

    naphtha to complex chemical reactions, at h temperature and ... at is leaving any stage of the platinum reforming reactors in terms of ... In this study, only platinum reforming .... IV. Hydrocracking of paraffinic hydrocarbons: +. →. ( +. +. +. +. ) (18).

  16. Novel platinum black electroplating technique improving mechanical stability.

    Science.gov (United States)

    Kim, Raeyoung; Nam, Yoonkey

    2013-01-01

    Platinum black microelectrodes are widely used as an effective neural signal recording sensor. The simple fabrication process, high quality signal recording and proper biocompatibility are the main advantages of platinum black microelectrodes. When microelectrodes are exposed to actual biological system, various physical stimuli are applied. However, the porous structure of platinum black is vulnerable to external stimuli and destroyed easily. The impedance level of the microelectrode increases when the microelectrodes are damaged resulting in decreased recording performance. In this study, we developed mechanically stable platinum black microelectrodes by adding polydopamine. The polydopamine layer was added between the platinum black structures by electrodeposition method. The initial impedance level of platinum black only microelectrodes and polydopamine added microelectrodes were similar but after applying ultrasonication the impedance value dramatically increased for platinum black only microelectrodes, whereas polydopamine added microelectrodes showed little increase which were nearly retained initial values. Polydopamine added platinum black microelectrodes are expected to extend the availability as neural sensors.

  17. Fast cleavage of a diselenide induced by a platinum(II)-methionine complex and its biological implications.

    Science.gov (United States)

    Liu, Qin; Wang, Xiaoyong; Yang, Xiaoliang; Liang, Xiao; Guo, Zijian

    2010-11-01

    Platinum-based anticancer drugs such as cisplatin induce increased oxidative stress and oxidative damage of DNA and other cellular components, while selenium plays an important role in the antioxidant defense system. In this study, the interaction between a platinum(II) methionine (Met) complex [Pt(Met)Cl(2)] and a diselenide compound selenocystine [(Sec)(2)] was studied by electrospray ionization mass spectrometry, high performance liquid chromatography mass spectrometry, and (1)H NMR spectroscopy. The results demonstrate that the diselenide bond in (Sec)(2) can readily and quickly be cleaved by the platinum complex. Formation of the selenocysteine (Sec) bridged dinuclear complex [Pt(2)(Met-S,N)(2)(μ-Sec-Se,Cl)](3+) and Sec chelated species [Pt(Met-S,N)(Sec-Se,N)](2+) was identified at neutral and acidic media, which seems to result from the intermediate [Pt(Met-S,N)(Sec-Se)Cl](+). An accelerated formation of S-Se and S-S bonds was also observed when (Sec)(2) reacted with excessive glutathione in the presence of [Pt(Met)Cl(2)]. These results imply that the mechanism of activity and toxicity of platinum drugs may be related to their fast reaction with seleno-containing biomolecules, and the chemoprotective property of selenium agents against cisplatin-induced toxicity could also be connected with such reactions.

  18. Platinum uptake from chloride solutions using biosorbents

    Directory of Open Access Journals (Sweden)

    Mehmet Hakan Morcali

    2013-04-01

    Full Text Available Present work investigates platinum uptake from synthetically prepared, dilute platinum-bearing solutions using biomass residues, i.e. pistachio nut shell and rice husk, which are abundant in Turkey, and provides a comparison between these two biosorbents. Effects of the different uptake parameters, sorbent dosage, contact time, temperature and pH of solution on platinum uptake (% were studied in detail on a batch sorption. Before the pistachio nut shell was activated, platinum uptake (% was poor compared to the rice husk. However, after the pistachio nut shell was activated at 1000 °C under an argon atmosphere, the platinum uptake (% increased two-fold. The pistachio nut shell (original and activated and rice husk were shown to be better than commercially available activated carbon in terms of adsorption capacity. These two sorbents have also been characterized by FTIR and SEM. Adsorption equilibrium data best complied with the Langmuir isotherm model. Maximum adsorption capacities, Qmax, at 25 °C were found to be 38.31 and 42.02 mg.g- 1for the activated pistachio nut shell and rice husk, respectively. Thermodynamic calculations using the measured ∆H°, ∆S° and ∆G° values indicate that the uptake process was spontaneous and endothermic. The experimental data were shown to be fit the pseudo-second-order kinetic model.

  19. Electrochemical Fabrication and Electrocatalytic Properties of Nanostructured Mesoporous Platinum Microelectrodes

    Institute of Scientific and Technical Information of China (English)

    Mengyan NIE; Joanne M. Elliott

    2005-01-01

    Electrodeposition from a lyotropic liquid crystal template medium was used to produce nanostructured platinum microelectrodes with high specific surface area and high mass transport efficiency. Compared to polished and conventional platinized microelectrodes, well-ordered nanostructured platinum microelectrodes exhibited enhanced electrocatalytic properties for oxygen and ascorbic acid, whilst well-ordered nanostructured platinum microelectrodes offered improved electrocatalytic properties for oxygen reduction compared to disordered nanostructured platinum microelectrodes.

  20. Mechanism for Self-Reacted Friction Stir Welding

    Science.gov (United States)

    Venable, Richard; Bucher, Joseph

    2004-01-01

    A mechanism has been designed to apply the loads (the stirring and the resection forces and torques) in self-reacted friction stir welding. This mechanism differs somewhat from mechanisms used in conventional friction stir welding, as described below. The tooling needed to apply the large reaction loads in conventional friction stir welding can be complex. Self-reacted friction stir welding has become popular in the solid-state welding community as a means of reducing the complexity of tooling and to reduce costs. The main problems inherent in self-reacted friction stir welding originate in the high stresses encountered by the pin-and-shoulder assembly that produces the weld. The design of the present mechanism solves the problems. The mechanism includes a redesigned pin-and-shoulder assembly. The welding torque is transmitted into the welding pin by a square pin that fits into a square bushing with set-screws. The opposite or back shoulder is held in place by a Woodruff key and high-strength nut on a threaded shaft. The Woodruff key reacts the torque, while the nut reacts the tensile load on the shaft.

  1. Experimental Vortex Identification and Characterization in Reacting Jets in Crossflow

    Science.gov (United States)

    Nair, Vedanth; Emerson, Ben; Lieuwen, Timothy

    2016-11-01

    Reacting jets in crossflow (JICF) is an important canonical flow field in combustion problems where there is strong coupling between heat release and the evolution of vortical structures. We use vortex identification studies to experimentally characterize the spatial evolution of vortex dynamics in a reacting JICF. A vortex identification algorithm was designed to operate on particle image velocimetry (PIV) data and its raw Mie scattering images. The algorithm uses the velocity fields to obtain comparisons between the strain rate and the rotation rate. Additionally, the algorithm uses the raw Mie scattering data to identify regions where the high acceleration at vortex cores has centrifuged seeding particles out of the vortex cores. Together, these methods are used to estimate the vortex location and circulation. Analysis was done on 10 kHz PIV data from a reacting JICF experiment, and the resulting vortex trajectory, and growth rate statistics are presented. Results are compared between non-reacting JICF and reacting studies performed with different jet density ratios and different levels of acoustic forcing. We observed how the density ratio, the frequency and amplitude of the acoustic forcing affected the vortex characteristics and growth rate.

  2. Extensions of Callendar's equations for platinum resistance thermometry

    DEFF Research Database (Denmark)

    Diamond, Joseph M.

    1969-01-01

    measurements where the platinum thermometer and the measurement means may be less than ideal. To this end. Callendar's definition of platinum temperature is generalized to mean the temperature found by linear interpolation with a platinum thermometer between given fixed points and using a given measurement...

  3. Platinum Publications as of April 30, 2014 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  4. Platinum Publications, September 30–October 27, 2016 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 42 prestigious science journals. This list represents articles published during the time period shown above, as generated from PubMed. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  5. Platinum Publications as of June 25, 2014 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  6. Platinum Publications, July 1–July 28, 2016 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 42 prestigious science journals. This list represents articles published during the time period shown above, as generated from PubMed. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  7. Platinum Publications as of March 6, 2014 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  8. Platinum Publications, October 1–29, 2015 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 42 prestigious science journals. This list represents articles published during the time period shown above, as generated from PubMed. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  9. Platinum Publications, December 1–December 29, 2016 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 42 prestigious science journals. This list represents articles published during the time period shown above, as generated from PubMed. Articles designated as Platinum Highlights are noteworthy articles selected from among the most recently published Platinum Publications.

  10. Platinum Publications as of May 29, 2014 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  11. Platinum Publications as of September 25, 2014 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  12. Platinum Publications, January 26–February 28, 2017 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 42 prestigious science journals. This list represents articles published during the time period shown above, as generated from PubMed. Articles designated as Platinum Highlights are noteworthy articles selected from among the most recently published Platinum Publications.

  13. Platinum Publications as of December 3, 2013 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  14. Deposition of the platinum crystals on the carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new technique and the affecting factors for depositing platinum on the carbon nanotubes were investigated. The results show that the deposited platinum crystals in the atmosphere of hydrogen or nitrogen have a small size and a homogeneous distribution on the surface of the carbon nanotubes. The pretreatment would decrease the platinum particles on the carbon nanotubes significantly.

  15. 76 FR 8627 - Revision of Class E Airspace; Platinum, AK

    Science.gov (United States)

    2011-02-15

    ... Federal Aviation Administration 14 CFR Part 71 Revision of Class E Airspace; Platinum, AK AGENCY: Federal... Platinum, AK, to accommodate the addition of a Standard Instrument Approach Procedure (SIAP), at the Platinum Airport. The FAA is taking this action to enhance safety and management of Instrument Flight...

  16. Surface decorated platinum carbonyl clusters

    Science.gov (United States)

    Ciabatti, Iacopo; Femoni, Cristina; Iapalucci, Maria Carmela; Longoni, Giuliano; Zacchini, Stefano; Zarra, Salvatore

    2012-06-01

    Four molecular Pt-carbonyl clusters decorated by Cd-Br fragments, i.e., [Pt13(CO)12{Cd5(μ-Br)5Br2(dmf)3}2]2- (1), [Pt19(CO)17{Cd5(μ-Br)5Br3(Me2CO)2}{Cd5(μ-Br)5Br(Me2CO)4}]2- (2), [H2Pt26(CO)20(CdBr)12]8- (3) and [H4Pt26(CO)20(CdBr)12(PtBr)x]6- (4) (x = 0-2), have been obtained from the reactions between [Pt3n(CO)6n]2- (n = 2-6) and CdBr2.H2O in dmf at 120 °C. The structures of these molecular clusters with diameters of 1.5-2 nm have been determined by X-ray crystallography. Both 1 and 2 are composed of icosahedral or bis-icosahedral Pt-CO cores decorated on the surface by Cd-Br motifs, whereas 3 and 4 display a cubic close packed Pt26Cd12 metal frame decorated by CO and Br ligands. An oversimplified and unifying approach to interpret the electron count of these surface decorated platinum carbonyl clusters is suggested, and extended to other low-valent organometallic clusters and Au-thiolate nanoclusters.Four molecular Pt-carbonyl clusters decorated by Cd-Br fragments, i.e., [Pt13(CO)12{Cd5(μ-Br)5Br2(dmf)3}2]2- (1), [Pt19(CO)17{Cd5(μ-Br)5Br3(Me2CO)2}{Cd5(μ-Br)5Br(Me2CO)4}]2- (2), [H2Pt26(CO)20(CdBr)12]8- (3) and [H4Pt26(CO)20(CdBr)12(PtBr)x]6- (4) (x = 0-2), have been obtained from the reactions between [Pt3n(CO)6n]2- (n = 2-6) and CdBr2.H2O in dmf at 120 °C. The structures of these molecular clusters with diameters of 1.5-2 nm have been determined by X-ray crystallography. Both 1 and 2 are composed of icosahedral or bis-icosahedral Pt-CO cores decorated on the surface by Cd-Br motifs, whereas 3 and 4 display a cubic close packed Pt26Cd12 metal frame decorated by CO and Br ligands. An oversimplified and unifying approach to interpret the electron count of these surface decorated platinum carbonyl clusters is suggested, and extended to other low-valent organometallic clusters and Au-thiolate nanoclusters. CCDC 867747 and 867748. For crystallographic data in CIF or other electronic format see DOI: 10.1039/c2nr30400g

  17. Autonomous movement of platinum-loaded stomatocytes.

    Science.gov (United States)

    Wilson, Daniela A; Nolte, Roeland J M; van Hest, Jan C M

    2012-02-26

    Polymer stomatocytes are bowl-shaped structures of nanosize dimensions formed by the controlled deformation of polymer vesicles. The stable nanocavity and strict control of the opening are ideal for the physical entrapment of nanoparticles which, when catalytically active, can turn the stomatocyte morphology into a nanoreactor. Herein we report an approach to generate autonomous movement of the polymer stomatocytes by selectively entrapping catalytically active platinum nanoparticles within their nanocavities and subsequently using catalysis as a driving force for movement. Hydrogen peroxide is free to access the inner stomatocyte cavity, where it is decomposed by the active catalyst (the entrapped platinum nanoparticles) into oxygen and water. This generates a rapid discharge, which induces thrust and directional movement. The design of the platinum-loaded stomatocytes resembles a miniature monopropellant rocket engine, in which the controlled opening of the stomatocytes directs the expulsion of the decomposition products away from the reaction chamber (inner stomatocyte cavity).

  18. 2-Methoxycycloocta-1,5-dienyl platinum complexes as precursors for platinum nanoparticles

    Indian Academy of Sciences (India)

    Ninad Ghavale; Sandip Dey; Vimal K Jain; R Tewari

    2009-02-01

    Thermolysis of [Pt2 (-OR)2 (C8H12OMe)2] (R = Me or Ac) in hexadecylamine (HDA) at 210°C under argon atmosphere gave platinum nanoparticles which were characterized by XRD, EDAX and TEM analysis. Both spherical (∼ 10 nm) and rod-like (∼ 19 nm length with aspect ratio of 2.3) face centred cubic (fcc) platinum metal nanoparticles could be isolated. The thermogravimetric analyses of these complexes revealed that they undergo a single step decomposition leading to the formation of platinum metal powder.

  19. REACT: Resettable Hold Down and Release Actuator for Space Applications

    Science.gov (United States)

    Nava, Nestor; Collado, Marcelo; Cabás, Ramiro

    2014-07-01

    A new HDRA based on SMA technology, called REACT, has been designed for development of loads and appendixes in space applications. This design involves a rod supported by spheres that block its axial movement during a preload application. The rod shape allows misalignment and blocks the rotation around axial axis for a proper installation of the device. Because of the high preload requirements for this type of actuators, finite element analysis (FEA) has been developed in order to check the structure resistance. The results of the FEA have constrained the REACT design, in terms of dimensions, materials, and shape of the mechanical parts. A complete test campaign for qualification of REACT is proposed. Several qualification models are intended to be built for testing in parallel. Therefore, it is a way to demonstrate margins which allows getting some statistics.

  20. Estimating Sulfur hexafluoride (SF6) emissions in China using atmospheric observations and inverse modeling

    Science.gov (United States)

    Fang, X.; Thompson, R.; Saito, T.; Yokouchi, Y.; Li, S.; Kim, J.; Kim, K.; Park, S.; Graziosi, F.; Stohl, A.

    2013-12-01

    With a global warming potential of around 22800 over a 100-year time horizon, sulfur hexafluoride (SF6) is one of the greenhouse gases regulated under the Kyoto Protocol. Global SF6 emissions have been increasing since circa the year 2000. The reason for this increase has been inferred to be due to rapidly increasing emissions in developing countries that are not obligated to report their annual emissions to the United Nations Framework Convention on Climate Change, notably China. In this study, SF6 emissions during the period 2006-2012 for China and other East Asian countries were determined using in-situ atmospheric measurements and inverse modeling. We performed various inversion sensitivity tests, which show the largest uncertainties in the a posteriori Chinese emissions are associated with the a priori emissions used and their uncertainty, the station network, as well as the meteorological input data. The overall relative uncertainty of the a posteriori emissions in China is estimated to be 17% in 2008. Based on sensitivity tests, we employed the optimal parameters in our inversion setup and performed yearly inversions for the study period. Inversion results show that the total a posteriori SF6 emissions from China increased from 1420 × 245 Mg/yr in 2006 to 2741 × 472 Mg/yr in 2009 and stabilized thereafter. The rapid increase in emissions reflected a fast increase in SF6 consumption in China, a result also found in bottom-up estimates. The a posteriori emission map shows high emissions concentrated in populated parts of China. During the period 2006-2012, emissions in northwestern and northern China peaked around the year 2009, while emissions in eastern, central and northeastern China grew gradually during almost the whole period. Fluctuating emissions are observed for southwestern China. These regional differences should be caused by changes of provincial SF6 usage and by shifts of usage among different sectors. Fig. 1. Footprint emission sensitivity

  1. Unsaturated platinum-rhenium cluster complexes. Synthesis, structures and reactivity.

    Science.gov (United States)

    Adams, Richard D; Captain, Burjor; Smith, Mark D; Beddie, Chad; Hall, Michael B

    2007-05-09

    Two new compounds PtRe3(CO)12(PBut3)(micro-H)3, 9, and PtRe2(CO)9(PBut3)(micro-H)2, 10, were obtained from the reaction of Pt(PBut3)2 with Re3(CO)12(micro-H3), 8, at room temperature. Compound 9 contains a butterfly cluster of four metals formed by the insertion of the platinum atom from a Pt(PBut3) group into one of the hydride-bridged metal-metal bonds of 8. The three hydrido ligands are bridging ligands across each of three new Pt-Re bonds. Compound 10 contains a triangular PtRe2 cluster with two hydrido ligands; one bridges a Pt-Re bond, and the other bridges the Re-Re bond. The new compound Pt2Re2(CO)7(PBut3)2(micro-H)2, 11, was obtained from the reaction of 8 with Pt(PBut3)2 in hexane at reflux. Compound 11 was also obtained from 10 by reaction with an additional quantity of Pt(PBut3)2. Compound 11 contains a tetrahedral cluster of four metal atoms with two dynamically active hydrido ligands. A CO ligand on one of the two platinum atoms also exchanges between the two platinum atoms rapidly on the NMR time scale. Compound 11 is electronically unsaturated and was found to add hydrogen at room temperature to form the tetrahydrido cluster complex, Pt2Re2(CO)7(PBut3)2(micro-H)4, 12. Compound 12 has a structure similar to 11 but contains one triply bridging hydrido ligand, two edge bridging hydrido ligands, and one terminal hydrido ligand on one of the two platinum atoms. A kinetic isotope effect D/H of 1.5(1) was determined for the addition of H2 to 11. Hydrogen can be eliminated from 12 by heating to 97 degrees C or by the application of UV-vis irradiation at room temperature. Compound 12 adds CO at room temperature to yield the complex Pt2Re2(CO)8(PBut3)2(micro-H)4, 13, which contains a planar cluster of four metal atoms with a Pt-Pt bond and four edge bridging hydrido ligands. Compounds 11 and 12 react with Pt(PBut3)2 to yield the known five metal cluster complexes Pt3Re2(CO)6(PBut3)3(micro-H)2, 14, and Pt3Re2(CO)6(PBut3)3(micro-H)4, 15, respectively. Density

  2. A PDF closure model for compressible turbulent chemically reacting flows

    Science.gov (United States)

    Kollmann, W.

    1992-01-01

    The objective of the proposed research project was the analysis of single point closures based on probability density function (pdf) and characteristic functions and the development of a prediction method for the joint velocity-scalar pdf in turbulent reacting flows. Turbulent flows of boundary layer type and stagnation point flows with and without chemical reactions were be calculated as principal applications. Pdf methods for compressible reacting flows were developed and tested in comparison with available experimental data. The research work carried in this project was concentrated on the closure of pdf equations for incompressible and compressible turbulent flows with and without chemical reactions.

  3. Electrochemical Analysis of the Electrodeposition of Platinum Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hae-Min; Cho, Sung-Woon; Kim, Jun-Hyun; Kim, Chang-Koo [Ajou University, Suwon (Korea, Republic of)

    2015-10-15

    A bath for electrodeposition of platinum nanoparticles on low-cost graphite substrates was developed to attach nanoparticles directly onto a substrate, and electrochemical characteristics of the electrodeposition of platinum nanoparticles were investigated. The reaction mechanism was examined by the analysis of polarization behavior. Cyclic voltammetry measurements revealed that the electrodeposition of platinum nanoparticles was limited by mass transfer. The chronoamperometric study showed an instantaneous nucleation mechanism during the electrodeposition of platinum nanoparticles on graphite. Because graphite is much cheaper than other carbon-based substrates, the electrodeposition of platinum nanoparticles on the graphite is expected to have useful applications.

  4. Outpatient desensitization in selected patients with platinum hypersensitivity reactions.

    Science.gov (United States)

    O'Malley, David M; Vetter, Monica Hagan; Cohn, David E; Khan, Ambar; Hays, John L

    2017-06-01

    Platinum-based chemotherapies are a standard treatment for both initial and recurrent gynecologic cancers. Given this widespread use, it is important to be aware of the features of platinum hypersensitivity reactions and the subsequent treatment of these reactions. There is also increasing interest in the development of desensitization protocols to allow patients with a history of platinum hypersensitivity to receive further platinum based therapy. In this review, we describe the management of platinum hypersensitivity reactions and the desensitization protocols utilized at our institution. We also describe the clinical categorizations utilized to triage patients to appropriate desensitization protocols. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Synthesis and characterization of new platinum(II) and platinum(IV) triphyrin complexes.

    Science.gov (United States)

    Xue, Zhaoli; Kuzuhara, Daiki; Ikeda, Shinya; Okujima, Tetsuo; Mori, Shigeki; Uno, Hidemitsu; Yamada, Hiroko

    2013-02-18

    Metalation of 6,13,20,21-tetrakis(4-methylphenyl)-22H-tribenzo[14]triphyrin(2.1.1) with PtCl(2) gave a platinum(II) complex having a square-planar coordination structure with two pyrrolic nitrogen atoms and two chloride ions, with a saddle-shaped macrocycle. This platinum(II) complex was easily oxidized by air to an octahedral platinum(IV) complex coordinated by three pyrrolic nitrogen atoms as a tridentate monoanionic cyclic ligand and three chloride ions. When platinum(II) triphyrin was crystallized in air, an oxygen atom was incorporated between two α-carbon atoms of the pyrroles as an oxygen bridge to intercept the 14π aromatic system.

  6. Metal-free reduction of the greenhouse gas sulfur hexafluoride, formation of SF5 containing ion pairs and the application in fluorinations

    KAUST Repository

    Rueping, Magnus

    2017-05-04

    A protocol for the fast and selective two-electron reduction of the potent greenhouse gas sulfur hexafluoride (SF6) by organic electron donors at ambient temperature has been developed. The reaction yields solid ion pairs consisting of donor dications and SF5-anions which can be effectively used in fluorination reactions.

  7. Anticancer platinum (IV) prodrugs with novel modes of activity.

    Science.gov (United States)

    Chin, Chee Fei; Wong, Daniel Yuan Qiang; Jothibasu, Ramasamy; Ang, Wee Han

    2011-01-01

    Over the past four decades, the search for improved platinum drugs based on the classical platinum (II)-diam(m)ine pharmacophore has yielded only a handful of successful candidates. New methodologies centred on platinum (IV) complexes, with better stability and expanded coordination spheres, offer the possibility of overcoming limitations inherent to platinum (II) drugs. In this review, novel strategies of targeting and killing cancer cells using platinum (IV) constructs are discussed. These approaches exploit the unique electrochemical characteristics and structural attributes of platinum (IV) complexes as a means of developing anticancer prodrugs that can target and selectively destroy cancer cells. Anticancer platinum (IV) prodrugs represent promising new strategies as targeted chemotherapeutic agents in the ongoing battle against cancer.

  8. The Dynamics of Platinum Precipitation in an Ion Exchange Membrane

    CERN Document Server

    Burlatsky, S F; Atrazhev, V V; Dmitriev, D V; Kuzminyh, N Y; Erikhman, N S

    2013-01-01

    Microscopy of polymer electrolyte membranes that have undergone operation under fuel cell conditions, have revealed a well defined band of platinum in the membrane. Here, we propose a physics based model that captures the mechanism of platinum precipitation in the polymer electrolyte membrane. While platinum is observed throughout the membrane, the preferential growth of platinum at the band of platinum is dependent on the electrochemical potential distribution in the membrane. In this paper, the location of the platinum band is calculated as a function of the gas concentration at the cathode and anode, gas diffusion coefficients and solubility constants of the gases in the membrane, which are functions of relative humidity. Under H2/N2 conditions the platinum band is located near the cathode-membrane interface, as the oxygen concentration in the cathode gas stream increases and/or the hydrogen concentration in the anode gas stream decreases, the band moves towards the anode. The model developed in this paper...

  9. Direct simulations of chemically reacting turbulent mixing layers, part 2

    Science.gov (United States)

    Metcalfe, Ralph W.; Mcmurtry, Patrick A.; Jou, Wen-Huei; Riley, James J.; Givi, Peyman

    1988-01-01

    The results of direct numerical simulations of chemically reacting turbulent mixing layers are presented. This is an extension of earlier work to a more detailed study of previous three dimensional simulations of cold reacting flows plus the development, validation, and use of codes to simulate chemically reacting shear layers with heat release. Additional analysis of earlier simulations showed good agreement with self similarity theory and laboratory data. Simulations with a two dimensional code including the effects of heat release showed that the rate of chemical product formation, the thickness of the mixing layer, and the amount of mass entrained into the layer all decrease with increasing rates of heat release. Subsequent three dimensional simulations showed similar behavior, in agreement with laboratory observations. Baroclinic torques and thermal expansion in the mixing layer were found to produce changes in the flame vortex structure that act to diffuse the pairing vortices, resulting in a net reduction in vorticity. Previously unexplained anomalies observed in the mean velocity profiles of reacting jets and mixing layers were shown to result from vorticity generation by baroclinic torques.

  10. Modeling and design of reacting systems with phase transfer catalysis

    DEFF Research Database (Denmark)

    Piccolo, Chiara; Hodges, George; Piccione, Patrick M.;

    2011-01-01

    , some of the design issues related to improved reaction operation are analyzed. Since the solubility of the different forms of the PTC in the organic solvent affects ultimately the catalyst partition coefficients, therefore, the organic solvent plays an important role in the design of PTC-based reacting...

  11. Termite Proteins Cross-React with Cockroach Allergens

    Science.gov (United States)

    Shrimp are among a group of 8 foods that commonly cause food allergy, and shrimp allergens have been demonstrated to cross-react with arthropod proteins, such as those from cockroaches. Edible insects are beginning to be popularized as an alternate source of protein and have a high nutrition value....

  12. Moment estimation for chemically reacting systems by extended Kalman filtering

    NARCIS (Netherlands)

    Ruess, J; Milias-Argeitis, A; Summers, S; Lygeros, J

    2011-01-01

    In stochastic models of chemically reacting systems that contain bimolecular reactions, the dynamics of the moments of order up to n of the species populations do not form a closed system, in the sense that their time-derivatives depend on moments of order n + 1. To close the dynamics, the moments o

  13. Platinum compounds with anti-tumour activity

    NARCIS (Netherlands)

    Plooy, A.C.M.; Lohman, P.H.M.

    1980-01-01

    Ten platinum (Pt) coordination complexes with different ligands, comprising both Pt(II) and Pt(IV) complexes of which the cis-compounds all possessed at least some anti-tumour activity and the trans-compounds were inactive, were tested as to their effect on cell survival and the induction and repair

  14. On the enzymatic formation of platinum nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Govender, Y.; Riddin, T. L. [Rhodes University, Department of Biochemistry, Microbiology and Biotechnology (South Africa); Gericke, M. [MINTEK (South Africa); Whiteley, C. G., E-mail: C.Whiteley@ru.ac.z [Rhodes University, Department of Biochemistry, Microbiology and Biotechnology (South Africa)

    2010-01-15

    A dimeric hydrogenase enzyme (44.5 and 39.4 kDa sub units) was isolated in a 39.5% yield from the fungus Fusarium oxysporum and purified 4.64-fold by ion exchange chromatography on Sephacryl S-200. Characterisation of the enzyme afforded pH and temperature optima of 7.5 and 38 {sup o}C, respectively, a half-life stability of 36 min and a V{sub max} and K{sub m} of 3.57 nmol min{sup -1} mL{sup -1} and 2.25 mM, respectively. This enzyme was inhibited (non-competitively) by hydrogen hexachloroplatinic acid (H{sub 2}PtCl{sub 6}) at 1 or 2 mM with a K{sub i} value of 118 {mu}M. Incubation of the platinum salt with the pure enzyme under an atmosphere of hydrogen and optimum enzyme conditions (pH 7.5, 38 {sup o}C) afforded <10% bioreduction after 8 h while at conditions suitable for platinum nanoparticle formation (pH 9, 65 {sup o}C) over 90% reduction took place after the same length of time. Cell-free extract from the fungal isolates produced nearly 90% bioreduction of the platinum salt under both pH and temperature conditions. The bioreduction of the platinum salt by a hydrogenase enzyme takes place by a passive process and not an active one as previously understood.

  15. Platinum catalysed hydrolytic amidation of unactivated nitriles

    NARCIS (Netherlands)

    Cobley, Christopher J.; Heuvel, Marco van den; Abbadi, Abdelilah; Vries, Johannes G. de

    2000-01-01

    The platinum(II) complex, [(Me2PO··H··OPMe2)PtH(PMe2OH)], efficiently catalyses the direct conversion of unactivated nitriles to N-substituted amides with both primary and secondary amines. Possible mechanisms for this reaction are discussed and evidence for initial amidine formation is reported.

  16. Targeting Platinum Compounds: synthesis and biological activity

    OpenAIRE

    VAN ZUTPHEN, Steven

    2005-01-01

    Inspired by cisplatin, the inorganic drug discovered by Barnett Rosenberg in 1965, the research described in this thesis uses targeting ligands, or ligands varied in a combinatorial fashion, to find platinum complexes with more specific modes of action. These studies have lead to the development of novel (solid-phase) synthetic methods and to the discovery of several compounds with promising biological properties.

  17. Targeting Platinum Compounds : synthesis and biological activity

    NARCIS (Netherlands)

    Zutphen, Steven van

    2005-01-01

    Inspired by cisplatin, the inorganic drug discovered by Barnett Rosenberg in 1965, the research described in this thesis uses targeting ligands, or ligands varied in a combinatorial fashion, to find platinum complexes with more specific modes of action. These studies have lead to the development of

  18. Skin Sensitizing Potency of Halogenated Platinum Salts.

    Science.gov (United States)

    The relationship between occupational exposure to halogenated platinum (Pt) salts and Pt-specific allergic sensitization is well-established. Although human case reports and clinical studies demonstrate that Pt salts are potent skin sensitizers, no studies have been published tha...

  19. Platinum catalysed hydrolytic amidation of unactivated nitriles

    NARCIS (Netherlands)

    Cobley, Christopher J.; Heuvel, Marco van den; Abbadi, Abdelilah; Vries, Johannes G. de

    2000-01-01

    The platinum(II) complex, [(Me2PO··H··OPMe2)PtH(PMe2OH)], efficiently catalyses the direct conversion of unactivated nitriles to N-substituted amides with both primary and secondary amines. Possible mechanisms for this reaction are discussed and evidence for initial amidine formation is reported. Is

  20. Technology, Safety and Costs of Decommissioning a Reference Uranium Hexafluoride Conversion Plant

    Energy Technology Data Exchange (ETDEWEB)

    Elder, H. K.

    1981-10-01

    Safety and cost information is developed for the conceptual decommissioning of a commercial uranium hexafluoride conversion (UF{sub 6}) plant. Two basic decommissioning alternatives are studied to obtain comparisons between cost and safety impacts: DECON, and passive SAFSTOR. A third alternative, DECON of the plant and equipment with stabilization and long-term care of lagoon wastes. is also examined. DECON includes the immediate removal (following plant shutdown) of all radioactivity in excess of unrestricted release levels, with subsequent release of the site for public use. Passive SAFSTOR requires decontamination, preparation, maintenance, and surveillance for a period of time after shutdown, followed by deferred decontamination and unrestricted release. DECON with stabilization and long-term care of lagoon wastes (process wastes generated at the reference plant and stored onsite during plant operation} is also considered as a decommissioning method, although its acceptability has not yet been determined by the NRC. The decommissioning methods assumed for use in each decommissioning alternative are based on state-of-the-art technology. The elapsed time following plant shutdown required to perform the decommissioning work in each alternative is estimated to be: for DECON, 8 months; for passive SAFSTOR, 3 months to prepare the plant for safe storage and 8 months to accomplish deferred decontamination. Planning and preparation for decommissioning prior to plant shutdown is estimated to require about 6 months for either DECON or passive SAFSTOR. Planning and preparation prior to starting deferred decontamination is estimated to require an additional 6 months. OECON with lagoon waste stabilization is estimated to take 6 months for planning and about 8 months to perform the decommissioning work. Decommissioning cost, in 1981 dollars, is estimated to be $5.91 million for OECON. For passive SAFSTOR, preparing the facility for safe storage is estimated to cost $0

  1. Concurrent chemoradiotherapy comparison of taxanes and platinum versus 5-fluorouracil and platinum in nasopharyngeal carcinoma treatment

    Institute of Scientific and Technical Information of China (English)

    Chen Xichuang; Hong Yuan; Feng Jinhua; Ye Jianlin; Zheng Panpan; Guan Xiyin; You Xiaohong

    2014-01-01

    Background Nasopharyngeal carcinoma (NPC) is a squamous-cell carcinoma especially prevailing among the natives of southern China.The regimen of concurrent chemoradiotherapy (CCRT) that include platinum and 5-fluorouracil (5-FU)is considered to be the standard treatment for NPC.However,its clinical use is limited by its toxicity.Our purpose was to evaluate the efficacy and safety of the regimen of CCRT with taxanes and platinum versus the regimen of CCRT with 5-FU and platinum in NPC treatment.Methods Medline,the Cochrane library,and the Chinese medical literature database were searched for eligible studies.Meta-analysis was performed using Review Manager (Version 5.2).Results Six random controlled trials (RCTs) including 514 patients met our criteria.Meta-analysis showed that the regimen of CCRT with taxanes and platinum had an improved significant difference in complete remission (CR) and less incidence rate in adverse reactions such as gastrointestinal impairment grades Ⅲll-Ⅳ,liver and kidney impairment grades Ⅰ-Ⅱ,and radiodermatitis grades Ⅲ-Ⅳ versus the conventional regimen of CCRT with 5-FU and platinum,while the long-term effectiveness rate of overall survival,Iocoregional failure-free survival,or distant metastasis failure-free survival between the two groups was therapeutic equivalence.Conclusions The regimen of CCRT with taxanes and platinum in NPC therapy may be more efficient and safe compared to the conventional modality of 5-FU and platinum in CCRT.However,we need more high-quality studies of multi-center and randomized double-blind clinical trials to further compare,analyze,and confirm the findings.

  2. Experimental thermodynamics experimental thermodynamics of non-reacting fluids

    CERN Document Server

    Neindre, B Le

    2013-01-01

    Experimental Thermodynamics, Volume II: Experimental Thermodynamics of Non-reacting Fluids focuses on experimental methods and procedures in the study of thermophysical properties of fluids. The selection first offers information on methods used in measuring thermodynamic properties and tests, including physical quantities and symbols for physical quantities, thermodynamic definitions, and definition of activities and related quantities. The text also describes reference materials for thermometric fixed points, temperature measurement under pressures, and pressure measurements. The publicatio

  3. Chemically reacting supersonic flow calculation using an assumed PDF model

    Science.gov (United States)

    Farshchi, M.

    1990-01-01

    This work is motivated by the need to develop accurate models for chemically reacting compressible turbulent flow fields that are present in a typical supersonic combustion ramjet (SCRAMJET) engine. In this paper the development of a new assumed probability density function (PDF) reaction model for supersonic turbulent diffusion flames and its implementation into an efficient Navier-Stokes solver are discussed. The application of this model to a supersonic hydrogen-air flame will be considered.

  4. Physical gasdynamics of reacting media. Fizicheskaia gazodinamika reagiruiushchikh sred

    Energy Technology Data Exchange (ETDEWEB)

    Alekseev, B.V.; Grishin, A.M.

    1985-01-01

    The fundamentals of the mechanics of reacting gases (aerothermochemistry) are presented in a systematic manner. Topics discussed include the kinetic theory of gases, elements of thermodynamics and chemical kinetics, transfer coefficients and mathematical models of gas flows, and transfer processes in a radiating gas. Attention is also given to similarity criteria and classification of aerothermochemical phenomena, elements of combustion theory, and some aspects of boundary layer theory. 81 references.

  5. Flow Field Effects on Nucleation in a Reacting Mixture Layer.

    Science.gov (United States)

    1984-11-01

    chemically reacting flows has been analysed by Fendell (1965) who considered the effect of the straining motion in a stagnation point flow on ignition...stagnation point diffusion flame ( Fendell , 1965, Linan, 1974). In the present study the effect of the strain rate or velocity gradient on nucleation kinetics...Symposium (International) on Corn- bustion, 799-810, Academic Press. Fendell , F. E. (1965). Ignition and extinction in combustion of initially unmixed

  6. Acoustic imaging for diagnostics of chemically reacting systems

    Science.gov (United States)

    Ramohalli, K.; Seshan, P.

    1983-01-01

    The concept of local diagnostics, in chemically reacting systems, with acoustic imaging is developed. The elements of acoustic imaging through ellipsoidal mirrors are theoretically discussed. In a general plan of the experimental program, the first system is chosen in these studies to be a simple open jet, non premixed turbulent flame. Methane is the fuel and enriched air is the oxidizer. This simple chemically reacting flow system is established at a Reynolds number (based on cold viscosity) of 50,000. A 1.5 m diameter high resolution acoustic mirror with an f-number of 0.75 is used to map the acoustic source zone along the axis of the flame. The results are presented as acoustic power spectra at various distances from the nozzle exit. It is seen that most of the reaction intensity is localized in a zone within 8 diameters from the exit. The bulk reactions (possibly around the periphery of the larger eddies) are evenly distributed along the length of the flame. Possibilities are seen for locally diagnosing single zones in a multiple cluster of reaction zones that occur frequently in practice. A brief outline is given of the future of this work which will be to apply this technique to chemically reacting flows not limited to combustion.

  7. Remarkable NO oxidation on single supported platinum atoms.

    Science.gov (United States)

    Narula, Chaitanya K; Allard, Lawrence F; Stocks, G M; Moses-DeBusk, Melanie

    2014-11-28

    Our first-principles density functional theoretical modeling suggests that NO oxidation is feasible on fully oxidized single θ-Al2O3 supported platinum atoms via a modified Langmuir-Hinshelwood pathway. This is in contrast to the known decrease in NO oxidation activity of supported platinum with decreasing Pt particle size believed to be due to increased platinum oxidation. In order to validate our theoretical study, we evaluated single θ-Al2O3 supported platinum atoms and found them to exhibit remarkable NO oxidation activity. A comparison of turnover frequencies (TOF) of single supported Pt atoms with those of platinum particles for NO oxidation shows that single supported Pt atoms are as active as fully formed platinum particles. Thus, the overall picture of NO oxidation on supported Pt is that NO oxidation activity decreases with decreasing Pt particle size but accelerates when Pt is present only as single atoms.

  8. Deliberate Tracer Injections of Sulfur Hexafluoride on the West Florida Shelf in Support of: An AUV-based Investigation of the Role of Nutrient Variability in the Predictive Modeling of Physical Processes in the Littoral Ocean

    Science.gov (United States)

    2001-09-30

    hexafluoride and it includes development of sampling methods to characterize the tracer field with high spatial and temporal resolution in near real...tracer in essence "freezes" the processes under investigation in space in this dynamic shelf region. APROACH A cruise was performed on the...hexafluoride and it includes development of sampling methods to characterize the tracer field with high spatial and temporal resolution in near real-time

  9. Synthesis of Bimetallic Platinum Nanoparticles for Biosensors

    Directory of Open Access Journals (Sweden)

    Gerard M. Leteba

    2013-08-01

    Full Text Available The use of magnetic nanomaterials in biosensing applications is growing as a consequence of their remarkable properties; but controlling the composition and shape of metallic nanoalloys is problematic when more than one precursor is required for wet chemistry synthesis. We have developed a successful simultaneous reduction method for preparation of near-spherical platinum-based nanoalloys containing magnetic solutes. We avoided particular difficulties in preparing platinum nanoalloys containing Ni, Co and Fe by the identification of appropriate synthesis temperatures and chemistry. We used transmission electron microscopy (TEM to show that our particles have a narrow size distribution, uniform size and morphology, and good crystallinity in the as-synthesized condition. Energy dispersive spectroscopy (EDS and X-ray diffraction (XRD confirms the coexistence of Pt with the magnetic solute in a face-centered cubic (FCC solid solution.

  10. Catalytic converters as a source of platinum

    Directory of Open Access Journals (Sweden)

    A. Fornalczyk

    2011-10-01

    Full Text Available The increase of Platinum Group Metals demand in automotive industry is connected with growing amount of cars equipped with the catalytic converters. The paper presents the review of available technologies during recycling process. The possibility of removing platinum from the used catalytic converters applying pyrometallurgical and hyrdometallurgical methods were also investigated. Metals such as Cu, Pb, Ca, Mg, Cd were used in the pyrometallurgical research (catalytic converter was melted with Cu, Pb and Ca or Mg and Cd vapours were blown through the whole carrier. In hydrometallurgical research catalytic converters was dissolved in aqua regia. Analysis of Pt contents in the carrier before and after the process was performed by means of atomic absorption spectroscopy. Obtained result were discussed.

  11. Examining the surfaces in used platinum catalysts

    Directory of Open Access Journals (Sweden)

    Trumić B.

    2009-01-01

    Full Text Available For the purpose of finding more advanced platinum catalyst manufacturing technologies and achieving a higher degree of ammonia oxidation, metallographic characterization has been done on the surface of catalyst gauzes and catalyst gripper gauzes made from platinum and palladium alloys. For the examined samples of gauzes as well as the cross section of the wires, a chemical analysis was provided. The purpose of this paper is the metallographic characterization of examined alloys carried out by way of electronic microscopic scanning, X-rays as well as chemical assays which contributed greatly to a better understanding of the surface deactivation, in other words a better consideration of structural changes occurring on the wire surface.

  12. Stability of Porous Platinum Nanoparticles: Combined In Situ TEM and Theoretical Study

    DEFF Research Database (Denmark)

    Chang, Shery L. Y.; Barnard, Amanda S.; Dwyer, Christian

    2012-01-01

    Porous platinum nanoparticles provide a route for the development of catalysts that use less platinum without sacrificing catalytic performance. Here, we examine porous platinum nanoparticles using a combination of in situ transmission electron microscopy and calculations based on a first...

  13. Platinum Acetylide Two-Photon Chromophores (Preprint)

    Science.gov (United States)

    2007-04-01

    the higher energy range that lead to its photodegradation . Secondly, because there is a quadratic dependence of two-photon absorption (2PA) on the...to either an electron donating amino- fluorenyl or electron withdrawing benzothiazolyl-fluorene that are themselves known as two-photon absorbing dyes ...groups in place of phenyl groups have shown a doubling of the intrinsic cr2value at 740 nm.40,41In this paper we describe novel platinum dyes that

  14. Redeposition of electrochemically dissolved platinum as nanoparticles on carbon

    DEFF Research Database (Denmark)

    Norgaard, C. F.; Stamatin, S. N.; Skou, E. M.

    2014-01-01

    Electrochemical dissolution of platinum has been proposed by several research groups as an environmentally friendly way to recover platinum from catalytic structures such as fuel cell electrodes. For the case of electrochemical dissolution of platinum in hydrochloric acid electrolyte, the present...... on carbon was then identified, quantified, and the particle size evaluated by powder X-ray diffraction, thermogravimetric analysis and cyclic voltammetry. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved....

  15. Platinum germanium ordering in UPtGe

    Science.gov (United States)

    Hoffmann, Rolf-Dieter; Pöttgen, Rainer; Lander, Gerry H.; Rebizant, Jean

    2001-09-01

    The non-centrosymmetric structure of UPtGe was investigated by X-ray diffraction on both powders and single crystals: EuAuGe type, Imm2, a=432.86(5), b=718.81(8), c=751.66(9) pm, wR2=0.0738 for 399 F2 values and 22 variables. The platinum and germanium atoms form two-dimensional layers of puckered Pt 3Ge 3 hexagons with short PtGe intralayer distances of 252 and 253 pm. These condensed two-dimensionally infinite nets are interconnected to each other via weak PtPt contacts with bond distances of 300 pm. The two crystallographically independent uranium atoms are situated above and below the six-membered platinum-germanium rings. The U1 atoms have six closer germanium neighbors while the U2 atoms have six closer platinum neighbors. The group-subgroup relation with the KHg 2 type structure is presented.

  16. Equilibria, Kinetics, and Mechanism for Rapid Substitution Reactions Trans to Triphenylsilyl in Platinum(II) Complexes.

    Science.gov (United States)

    Wendt, Ola F.; Elding, Lars I.

    1997-12-17

    Fast substitution of chloride for bromide and iodide trans to triphenylsilyl in trans-PtCl(SiPh(3))(PMe(2)Ph)(2) has been studied by stopped-flow spectrophotometry in acetonitrile solution. Substitution is reversible with an observable solvent path via the solvento complex trans-[Pt(SiPh(3))(MeCN)(PMe(2)Ph)(2)](+), which has also been synthesized and characterized in solution. Rate constants for the forward and reverse direct substitution pathways are 2900 +/- 100 and 7500 +/- 300 for bromide and 14300 +/- 1100 and 81000 +/- 11000 M(-)(1) s(-)(1) for iodide as nucleophile. The solvento complex reacts ca. 10(3) times faster with iodide than the parent chloride complex, and its reactivity is some 2 orders of magnitude higher than the most reactive solvento species of platinum(II) studied so far. Halide substitution occurs with negative volumes and entropies of activation, but the nucleophilic discrimination is low, and the leaving ligand plays the most important role in the activation process, indicating an I(d) mechanism. Triphenylsilyl has a very high trans effect, comparable to that of ethene and methylisocyanide, due to extensive bond-weakening in the ground state, probably enforced by pi-acception in the transition state. Due to electronic and solvational effects the platinum(II) silyl moiety acts as a hard or borderline metal center in acetonitrile, the thermodynamic stability sequence of its halide complexes being Cl > Br > I, i.e. the reverse of what is usually observed for platinum(II) complexes.

  17. Preparation and Electrochemical Properties of Porous Platinum Electrode

    Institute of Scientific and Technical Information of China (English)

    HE Xin; CHEN Boxun; CHEN Qiao

    2012-01-01

    Porous platinum electrodes were prepared by adding YSZ,as an active material,in platinum paste.Relationship between microstructure and electrochemical performance of O2(g),Pt/YSZ electrode have been characterized by SEM and cyclic voltammetry.Results showed that the microstructure of platinum electrode is a significant impact on the cyclic voltammetry.With the increase of platinum electrode's porosity,the area of three-phase boundary of O2(g)/Pt/YSZ was increased.The electrochemical reactivity was also enhanced.These were presented as the increase of current density and cathode voltage in cyclic voltammetry.

  18. Controlled synthesis of porous platinum nanostructures for catalytic applications.

    Science.gov (United States)

    Cao, Yanqin; Zhang, Junwei; Yang, Yong; Huang, Zhengren; Long, Nguyen Viet; Nogami, Masayuki

    2014-02-01

    Porous platinum, that has outstanding catalytic and electrical properties and superior resistant characteristics to corrosion, has been widely applied in chemical, petrochemical, pharmaceutical, electronic, and automotive industries. As the catalytic activity and selectivity depend on the size, shape and structure of nanomaterials, the strategies for controlling these factors of platinum nanomaterials to get excellent catalytic properties are discussed. Here, recent advances in the design and preparation of various porous platinum nanostructures are reviewed, including wet-chemical synthesis, electro-deposition, galvanic replacement reaction and de-alloying technology. The applications of various platinum nanostructures are also discussed, especially in fuel cells.

  19. A monofunctional trinuclear platinum complex with steric hindrance demonstrates strong cytotoxicity against tumor cells.

    Science.gov (United States)

    Wu, Shangnong; Wang, Xiaoyong; He, Yafeng; Zhu, Zhenzhu; Zhu, Chengcheng; Guo, Zijian

    2014-10-01

    Polynuclear platinum complexes constitute a special class of hopeful antitumor agents. In this study, a Y-type monofunctional trinuclear platinum complex (MTPC) with 1,3,5-tris(pyridin-2-ylmethoxy)benzene, ammine and chloride as ligands was synthesized and characterized by (1)H NMR and electrospray ionization mass spectrometry (ESI-MS). The DNA binding mode of MTPC was investigated using circular dichroism spectroscopy and gel electrophoresis, and the reactivity of MTPC towards glutathione was studied by (1)H NMR and ESI-MS. The results show that MTPC can affect the conformation of calf-thymus DNA (CT-DNA) significantly and tends to form 1,4-GG rather than 1,2-GG intrastrand crosslinks, which are different from the instance of cisplatin. MTPC reacts with glutathione quite slowly in comparison with cisplatin because of the steric hindrance. The cytotoxicity of MTPC was tested on the human breast cancer cell line MCF-7, the human non-small-cell lung cancer cell line A549, and the human ovarian cancer cell line Skov-3 by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. MTPC is more potent than or comparable to cisplatin. The cellular inhibition mode of MTPC was examined by flow cytometry using MCF-7 cells. MTPC arrests the cell cycle mainly in G2 or M phase, while cisplatin arrests the cell cycle in S phase. Similar to cisplatin, MTPC kills the cells predominantly through an apoptotic pathway.

  20. Modified sodium diuranate process for the recovery of uranium from uranium hexafluoride transport cylinder wash solution

    Science.gov (United States)

    Meredith, Austin Dean

    Uranium hexafluoride (UF6) containment cylinders must be emptied and washed every five years in order to undergo recertification, according to ANSI standards. During the emptying of the UF6 from the cylinders, a thin residue, or heel, of UF6 is left behind. This heel must be removed in order for recertification to take place. To remove it, the inside of the containment cylinder is washed with acid and the resulting solution generally contains three or four kilograms of uranium. Thus, before the liquid solution can be disposed of, the uranium must be separated. A modified sodium diuranate (SDU) uranium recovery process was studied to support development of a commercial process. This process was sought to ensure complete uranium recovery, at high purity, in order that it might be reused in the nuclear fuel cycle. An experimental procedure was designed and carried out in order to verify the effectiveness of the commercial process in a laboratory setting. The experiments involved a small quantity of dried UO2F2 powder that was dosed with 3wt% FeF3 and was dissolved in water to simulate the cylinder wash solution. Each experiment series started with a measured amount of this powder mixture which was dissolved in enough water to make a solution containing about 120 gmU/liter. The experiments involved validating the modified SDU extraction process. A potassium diuranate (KDU) process was also attempted. Very little information exists regarding such a process, so the task was undertaken to evaluate its efficacy and determine whether a potassium process yields any significant differences or advantages as compared to a sodium process. However, the KDU process ultimately proved ineffective and was abandoned. Each of the experiments was organized into a series of procedures that started with the UO2F2 powder being dissolved in water, and proceeded through the steps needed to first convert the uranium to a diuranate precipitate, then to a carbonate complex solution, and finally

  1. Technology, Safety and Costs of Decommissioning a Reference Uranium Hexafluoride Conversion Plant

    Energy Technology Data Exchange (ETDEWEB)

    Elder, H. K.

    1981-10-01

    Safety and cost information is developed for the conceptual decommissioning of a commercial uranium hexafluoride conversion (UF{sub 6}) plant. Two basic decommissioning alternatives are studied to obtain comparisons between cost and safety impacts: DECON, and passive SAFSTOR. A third alternative, DECON of the plant and equipment with stabilization and long-term care of lagoon wastes. is also examined. DECON includes the immediate removal (following plant shutdown) of all radioactivity in excess of unrestricted release levels, with subsequent release of the site for public use. Passive SAFSTOR requires decontamination, preparation, maintenance, and surveillance for a period of time after shutdown, followed by deferred decontamination and unrestricted release. DECON with stabilization and long-term care of lagoon wastes (process wastes generated at the reference plant and stored onsite during plant operation} is also considered as a decommissioning method, although its acceptability has not yet been determined by the NRC. The decommissioning methods assumed for use in each decommissioning alternative are based on state-of-the-art technology. The elapsed time following plant shutdown required to perform the decommissioning work in each alternative is estimated to be: for DECON, 8 months; for passive SAFSTOR, 3 months to prepare the plant for safe storage and 8 months to accomplish deferred decontamination. Planning and preparation for decommissioning prior to plant shutdown is estimated to require about 6 months for either DECON or passive SAFSTOR. Planning and preparation prior to starting deferred decontamination is estimated to require an additional 6 months. OECON with lagoon waste stabilization is estimated to take 6 months for planning and about 8 months to perform the decommissioning work. Decommissioning cost, in 1981 dollars, is estimated to be $5.91 million for OECON. For passive SAFSTOR, preparing the facility for safe storage is estimated to cost $0

  2. Benchmark Gamma Spectroscopy Measurements of Uranium Hexafluoride in Aluminmum Pipe with a Sodium Iodide Detector

    Energy Technology Data Exchange (ETDEWEB)

    March-Leuba, Jose A [ORNL; Uckan, Taner [ORNL; Gunning, John E [ORNL; Brukiewa, Patrick D [ORNL; Upadhyaya, Belle R [ORNL; Revis, Stephen M [ORNL

    2010-01-01

    The expected increased demand in fuel for nuclear power plants, combined with the fact that a significant portion of the current supply from the blend down of weapons-source material will soon be coming to an end, has led to the need for new sources of enriched uranium for nuclear fuel. As a result, a number of countries have announced plans, or are currently building, gaseous centrifuge enrichment plants (GCEPs) to supply this material. GCEPs have the potential to produce uranium at enrichments above the level necessary for nuclear fuel purposes-enrichments that make the uranium potentially usable for nuclear weapons. As a result, there is a critical need to monitor these facilities to ensure that nuclear material is not inappropriately enriched or diverted for unintended use. Significant advances have been made in instrument capability since the current International Atomic Energy Agency (IAEA) monitoring methods were developed. In numerous cases, advances have been made in other fields that have the potential, with modest development, to be applied in safeguards applications at enrichment facilities. A particular example of one of these advances is the flow and enrichment monitor (FEMO). (See Gunning, J. E. et al., 'FEMO: A Flow and Enrichment Monitor for Verifying Compliance with International Safeguards Requirements at a Gas Centrifuge Enrichment Facility,' Proceedings of the 8th International Conference on Facility Operations - Safeguards Interface. Portland, Oregon, March 30-April 4th, 2008.) The FEMO is a conceptual instrument capable of continuously measuring, unattended, the enrichment and mass flow of {sup 235}U in pipes at a GCEP, and consequently increase the probability that the potential production of HEU and/or diversion of fissile material will be detected. The FEMO requires no piping penetrations and can be installed on pipes containing the flow of uranium hexafluoride (UF{sub 6}) at a GCEP. This FEMO consists of separate parts, a flow

  3. Dual-drug delivery of curcumin and platinum drugs in polymeric micelles enhances the synergistic effects: a double act for the treatment of multidrug-resistant cancer.

    Science.gov (United States)

    Scarano, Wei; de Souza, Paul; Stenzel, Martina H

    2015-01-01

    Combinational chemotherapy is often used to prevent drug induced resistance in cancer. The aim of this work is to test whether the co-delivery of drugs within one nanoparticle can result in increased synergistic effects of both drugs. Therefore, a micelle system with two different compartments, one for the drug curcumin and one for the conjugation of platinum drugs was designed. A triblock copolymer, based on the biodegradable polycaprolactone PCL, a PEG based shell and an amine bearing polymer as the interphase for the conjugation of platinum drugs was prepared by combination of ring-opening polymerization and RAFT polymerization. Curcumin was incorporated into the self-assembled onion-type micelle by physical encapsulation into the PCL core with an entrapment capacity of 6 wt%. The platinum(iv) drug oxoplatin was reacted with succinic anhydride to yield Pt(NH3)2Cl2[(COOH)2], which acted as the drug and as a crosslinker for the stabilisation of micelles. The size of the dual drug micelles was measured to be 38 nm by DLS, which was confirmed by TEM. The toxicity of the dual drug delivery system was tested against the A2780 human ovarian cancer cell line and compared with the IC50 value of micelles that deliver either curcumin or the platinum drug alone. The results were analysed using the CalcuSyn software. While curcumin and the platinum drug together without a carrier already showed synergy with a combination index ranging from 0.4 to 0.8, the combined delivery in one nanoparticle did enhance the synergistic effects resulting in a combination index of approximately 0.2-0.35. For comparison, a mixture of two nanoparticles, one with curcumin and the other with the platinum drug, was tested revealing a less noticeable synergistic effect compared to the co-delivery of both drugs in one drug carrier.

  4. The developmental neurotoxicity study of platinum compounds. Effects of cisplatin versus a novel Pt(II) complex on rat cerebellum.

    Science.gov (United States)

    Cerri, Silvia; Piccolini, Valeria M; Santin, Giada; Bottone, Maria G; De Pascali, Sandra A; Migoni, Danilo; Iadarola, Paolo; Fanizzi, Francesco P; Bernocchi, Graziella

    2011-01-01

    In the field of experimental oncology, many efforts are being carried out to search new platinum-based drugs overcoming the CNS toxicity and drug resistance. One of the adopted strategies is the synthesis of platinum compounds able to form Pt-DNA adducts different from the cisplatin ones or to react with other subcellular targets. In this context a novel Pt(II) complex, [Pt(O,O'-acac)(γ-acac)(DMS)](PtAcacDMS), was synthesized which reacts preferentially with protein thiols or thioethers. In this work we investigated the in vivo effects of cisplatin and PtAcacDMS on normal development. Moreover, to verify the dose-dependence of the effects, different groups of animals were treated with 5 μg/g or 10 μg/g body weight of cisPt and PtAcacDMS. We have focused our attention on the cerebellum because it provides a useful model system to evaluate the outcomes of perinatal treatment with chemotherapeutic agents on key CNS developmental processes such as neural cells proliferation, migration and differentiation. We have demonstrated the ability of both cisPt and PtAcacDMS to reach the brain tissue once injected. The brain platinum content after PtAcacDMS treatment was notably higher (approximately 4-fold as much) than after cisPt. The platinum accumulation in the brain was still considerable 7 days after PtAcacDMS administration. However, compared with cisplatin, PtAcacDMS induces less severe changes on fundamental events of neuroarchitecture development, such as no high apoptotic events, less altered granule cell migration and Purkinje cell dendrite growth, suggesting a low neurotoxicity of this new Pt complex for normal CNS. The mild damages could be attributable to the different subcellular target of this compound as well as to a greater efficiency of the cell repair system to recognize the drug-target adducts and to repair them. Together with the previously demonstrated antineoplastic effectiveness in vitro, the findings here reported suggest PtAcacDMS as a potential

  5. How much platinum passes the placental barrier? Analysis of platinum applications in 21 patients with cervical cancer during pregnancy.

    Science.gov (United States)

    Köhler, Christhardt; Oppelt, Peter; Favero, Giovanni; Morgenstern, Bernd; Runnebaum, Ingo; Tsunoda, Audrey; Schmittel, Alexander; Schneider, Achim; Mueller, Michael; Marnitz, Simone

    2015-08-01

    Cervical cancer is the most common solid cancer diagnosed in pregnancy. Platinum is an active drug in the treatment of patients with cervical cancer. In the second and third trimesters, platinum is used to prevent cancer progression until fetal maturity is reached. However, knowledge about the transplacental passage of platinum is very limited. Between May 2008 and June 2014, platinum-based neoadjuvant chemotherapy was applied to 21 consecutive patients with cervical cancer diagnosed in their second trimester. At the time of delivery by cesarean delivery, synchronous samples from maternal blood, umbilical cord blood, and amniotic fluid were taken and analyzed for platinum concentrations. The mean week of gestation at cancer diagnosis was 17 (13-23). On average 3 (range, 2-4) cycles of chemotherapy were applied. Cesarean deliveries were carried out between 30.4 and 36.5 weeks of gestation. Twenty-two healthy babies without renal, hepatic, auditory, or hematopoietic impairment were delivered. Platinum concentrations in umbilical cord blood and amniotic fluid were 23-65% and 11-42% of the maternal blood, respectively. This series on in vivo measurement of platinum concentrations in the fetomaternal compartment observed that because of consistently lower platinum values in the fetoplacental unit, a placental filtration mechanism of platinum may be assumed. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. ReACT Methodology Proof of Concept Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Bri Rolston; Sarah Freeman

    2014-03-01

    The Department of Energy’s Office of Electricity Delivery and Energy Reliability (DOE-OE) funded INL Researchers to evaluate a novel process for assessing and mitigating cyber security risks. The proof of concept level of the method was tested in an industry environment. This case study, plus additional case studies will support the further development of the method into a tool to assist industry in securing their critical networks. This report provides an understanding of the process developed in the Response Analysis and Characterization Tool (ReACT) project. This report concludes with lessons learned and a roadmap for final development of these tools for use by industry.

  7. Effect of reacted acidic monomer with calcium on bonding performance.

    Science.gov (United States)

    Fujita, K; Ma, S; Aida, M; Maeda, T; Ikemi, T; Hirata, M; Nishiyama, N

    2011-05-01

    We determined the number of reacted and unreacted 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) molecules with calcium during the demineralization process of hydroxyapatite or dentin by 10-MDP-based one-step (Clearfil Tri-S Bond, TS) or two-step self-etch adhesive (Clearfil SE Bond Primer, SE). We then examined the effects of the number of reacted and/or unreacted 10-MDP molecules on the initial bond strength and bond durability of the resultant adhesive layer. The null hypotheses were that (1) the etching efficacy of tooth apatite by 10-MDP used in TS was the same as that in SE, and (2) the unreacted 10-MDP polymer included within the adhesive layer does not affect bond durability. Addition of hydroxyapatite or dentin to the TS and SE resulted in decreases in the NMR peak intensities for 10-MDP. The peak intensity for 10-MDP showed a greater reduction in SE than in TS, consistent with the observation that SE provided significantly higher initial mean bond strengths than TS. Further, the unreacted 10-MDP polymer within the adhesive layer did not decrease the mean bond strength, despite the application of 20,000x thermo-cycling.

  8. Sticky Tunes: How Do People React to Involuntary Musical Imagery?

    Science.gov (United States)

    Williamson, Victoria J.; Liikkanen, Lassi A.; Jakubowski, Kelly; Stewart, Lauren

    2014-01-01

    The vast majority of people experience involuntary musical imagery (INMI) or ‘earworms’; perceptions of spontaneous, repetitive musical sound in the absence of an external source. The majority of INMI episodes are not bothersome, while some cause disruption ranging from distraction to anxiety and distress. To date, little is known about how the majority of people react to INMI, in particular whether evaluation of the experience impacts on chosen response behaviours or if attempts at controlling INMI are successful or not. The present study classified 1046 reports of how people react to INMI episodes. Two laboratories in Finland and the UK conducted an identical qualitative analysis protocol on reports of INMI reactions and derived visual descriptive models of the outcomes using grounded theory techniques. Combined analysis carried out across the two studies confirmed that many INMI episodes were considered neutral or pleasant, with passive acceptance and enjoyment being among the most popular response behaviours. A significant number of people, however, reported on attempts to cope with unwanted INMI. The most popular and effective behaviours in response to INMI were seeking out the tune in question, and musical or verbal distraction. The outcomes of this study contribute to our understanding of the aetiology of INMI, in particular within the framework of memory theory, and present testable hypotheses for future research on successful INMI coping strategies. PMID:24497938

  9. Sticky tunes: how do people react to involuntary musical imagery?

    Directory of Open Access Journals (Sweden)

    Victoria J Williamson

    Full Text Available The vast majority of people experience involuntary musical imagery (INMI or 'earworms'; perceptions of spontaneous, repetitive musical sound in the absence of an external source. The majority of INMI episodes are not bothersome, while some cause disruption ranging from distraction to anxiety and distress. To date, little is known about how the majority of people react to INMI, in particular whether evaluation of the experience impacts on chosen response behaviours or if attempts at controlling INMI are successful or not. The present study classified 1046 reports of how people react to INMI episodes. Two laboratories in Finland and the UK conducted an identical qualitative analysis protocol on reports of INMI reactions and derived visual descriptive models of the outcomes using grounded theory techniques. Combined analysis carried out across the two studies confirmed that many INMI episodes were considered neutral or pleasant, with passive acceptance and enjoyment being among the most popular response behaviours. A significant number of people, however, reported on attempts to cope with unwanted INMI. The most popular and effective behaviours in response to INMI were seeking out the tune in question, and musical or verbal distraction. The outcomes of this study contribute to our understanding of the aetiology of INMI, in particular within the framework of memory theory, and present testable hypotheses for future research on successful INMI coping strategies.

  10. Spectral kinetic energy transfer in turbulent premixed reacting flows.

    Science.gov (United States)

    Towery, C A Z; Poludnenko, A Y; Urzay, J; O'Brien, J; Ihme, M; Hamlington, P E

    2016-05-01

    Spectral kinetic energy transfer by advective processes in turbulent premixed reacting flows is examined using data from a direct numerical simulation of a statistically planar turbulent premixed flame. Two-dimensional turbulence kinetic-energy spectra conditioned on the planar-averaged reactant mass fraction are computed through the flame brush and variations in the spectra are connected to terms in the spectral kinetic energy transport equation. Conditional kinetic energy spectra show that turbulent small-scale motions are suppressed in the burnt combustion products, while the energy content of the mean flow increases. An analysis of spectral kinetic energy transfer further indicates that, contrary to the net down-scale transfer of energy found in the unburnt reactants, advective processes transfer energy from small to large scales in the flame brush close to the products. Triadic interactions calculated through the flame brush show that this net up-scale transfer of energy occurs primarily at spatial scales near the laminar flame thermal width. The present results thus indicate that advective processes in premixed reacting flows contribute to energy backscatter near the scale of the flame.

  11. High speed turbulent reacting flows: DNS and LES

    Science.gov (United States)

    Givi, Peyman

    1990-01-01

    Work on understanding the mechanisms of mixing and reaction in high speed turbulent reacting flows was continued. Efforts, in particular, were concentrated on taking advantage of modern computational methods to simulate high speed turbulent flows. In doing so, two methodologies were used: large eddy simulations (LES) and direct numerical simulations (DNS). In the work related with LES the objective is to study the behavior of the probability density functions (pdfs) of scalar properties within the subgrid in reacting turbulent flows. The data base obtained by DNS for a detailed study of the pdf characteristics within the subgrid was used. Simulations are performed for flows under various initializations to include the effects of compressibility on mixing and chemical reactions. In the work related with DNS, a two-dimensional temporally developing high speed mixing layer under the influence of a second-order non-equilibrium chemical reaction of the type A + B yields products + heat was considered. Simulations were performed with different magnitudes of the convective Mach numbers and with different chemical kinetic parameters for the purpose of examining the isolated effects of the compressibility and the heat released by the chemical reactions on the structure of the layer. A full compressible code was developed and utilized, so that the coupling between mixing and chemical reactions is captured in a realistic manner.

  12. Modelling and sensitivity analysis of urinary platinum excretion in anticancer chemotherapy for the recovery of platinum

    DEFF Research Database (Denmark)

    Folens, Karel; Mortier, Séverine Thérèse F C; Baeten, Janis

    2016-01-01

    Platinum (Pt) based antineoplastics are important in cancer therapy. To date the Pt which is urinary excreted by the patients ends up in wastewater. This is disadvantageous from both an economic as from an ecological point of view because Pt is a valuable material and the excretion products are t...

  13. Exhaust system having a gold-platinum group metal catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Ragle, Christie Susan [Havana, IL; Silver, Ronald G [Peoria, IL; Zemskova, Svetlana Mikhailovna [Edelstein, IL; Eckstein, Colleen J [Metamora, IL

    2011-12-06

    A method of providing an exhaust treatment device is disclosed. The method includes applying a catalyst including gold and a platinum group metal to a particulate filter. The concentration of the gold and the platinum group metal is sufficient to enable oxidation of carbon monoxide and nitric oxide.

  14. Corrosion Studies of Platinum Nano-Particles for Fuel Cells

    DEFF Research Database (Denmark)

    Shim, Signe Sarah

    The main focus of the present thesis is on corrosion and prevention of corrosion of platinum particles supported on carbon. This is important for instance in connection with start up and shutdown of fuel cells. The degradation mechanism of platinum particles supported on carbon has been...

  15. Refurbishment of uranium hexafluoride cylinder storage yards C-745-K, L, M, N, and P and construction of a new uranium hexafluoride cylinder storage yard (C-745-T) at the Paducah Gaseous Diffusion Plant, Paducah, Kentucky

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-07-01

    The Paducah Gaseous Diffusion Plant (PGDP) is a uranium enrichment facility owned by the US Department of Energy (DOE). A residual of the uranium enrichment process is depleted uranium hexafluoride (UF6). Depleted UF6, a solid at ambient temperature, is stored in 32,200 steel cylinders that hold a maximum of 14 tons each. Storage conditions are suboptimal and have resulted in accelerated corrosion of cylinders, increasing the potential for a release of hazardous substances. Consequently, the DOE is proposing refurbishment of certain existing yards and construction of a new storage yard. This environmental assessment (EA) evaluates the impacts of the proposed action and no action and considers alternate sites for the proposed new storage yard. The proposed action includes (1) renovating five existing cylinder yards; (2) constructing a new UF6 storage yard; handling and onsite transport of cylinders among existing yards to accommodate construction; and (4) after refurbishment and construction, restacking of cylinders to meet spacing and inspection requirements. Based on the results of the analysis reported in the EA, DOE has determined that the proposed action is not a major Federal action that would significantly affect the quality of the human environment within the context of the National Environmental Policy Act of 1969. Therefore, DOE is issuing a Finding of No Significant Impact. Additionally, it is reported in this EA that the loss of less than one acre of wetlands at the proposed project site would not be a significant adverse impact.

  16. Platinum contamination issues in ferroelectric memories

    Science.gov (United States)

    Boubekeur, H.; Mikolajick, T.; Pamler, W.; Hopfner, J.; Frey, L.; Ryssel, H.

    2002-09-01

    The contamination risk of processing with platinum electrodes on device performance in ferroelectric memories is assessed in this work. Details of platinum diffusion to the active regions at annealing temperatures of 800 degC are investigated by secondary ion mass spectroscopy, deep level transient spectroscopy, and Rutherford backscattering spectrometry techniques. Cross sectional transmission electron microscopy and local elemental analysis by energy dispersive x-ray spectroscopy were used to examine the precipitation of Pt in defect free silicon as an eventual cause of gate oxide degradation. The impact of platinum contamination on device performance is evaluated under the typical ferroelectric memory processing conditions. Results from leakage current and charge to breakdown measurements of intentionally contaminated diode and metal-oxide-semiconductor (MOS) structures, respectively, are presented. The results show that the degradation depends strongly on device design and configuration. A phosphorus doped polysilicon plug, which has the function of connecting the select transistor to the capacitor module, provides effective gettering regions and prevents the diffusion of Pt atoms to the active regions. Under typical processing conditions, no evident Pt precipitates were observed and up to a concentration level of 4 x1014 atoms/cm2, the leakage current of intentionally contaminated diodes does not increase, if the contamination occurs after front-end phosphorus doped poly-Si processing. Results from constant current charge to breakdown show a small number of breakdown events due to redeposition of Pt at the periphery of the MOS structure. The risk of processing with Pt electrodes in ferroelectric memories requires great care. Precautions like sealing the back surface and incorporating phosphorus doped polysilicon as the plug material are necessary to avoid the detrimental effects of Pt.

  17. Synthesis and reactivity towards diiodine of palladium(II) and platinum(II) complexes with non-cyclic and cyclic ligands (C6H3{CH=NR1R2}2-2,6)-. End-on diiodine-platinum(II) bonding in macrocyclic [PtI(C6H3{CH2NMe(CH2)7MeNCH2}-2,6)(h1-I2)

    NARCIS (Netherlands)

    Koten, G. van; Beek, J.A.M. van; Dekker, G.P.C.M.; Wissing, E.; Zoutberg, M.C.; Stam, C.H.

    1990-01-01

    Several new organo-platinum(II) and -palladium(II) complexes [MX(C{6}H{3}{CH{2}NR}1{R}2{}{2}-2, 6)] (X = halide, M = Pt, Pd; R}1{ = R}2{ = Et; R}2{ = Me, R}1{ = }t{Bu, M = Pt: R}2{ = Me, R}1{ = Ph) have been synthesized from [PtCl{2}(SEt{2}){2}] or [PdCl{2}(COD)] (COD = 1, 5-cyclooctadiene) by react

  18. Synthesis and reactivity towards diiodine of palladium(II) and platinum(II) complexes with non-cyclic and cyclic ligands (C6H3{CH=NR1R2}2-2,6)-. End-on diiodine-platinum(II) bonding in macrocyclic [PtI(C6H3{CH2NMe(CH2)7MeNCH2}-2,6)(h1-I2)

    NARCIS (Netherlands)

    Koten, G. van; Beek, J.A.M. van; Dekker, G.P.C.M.; Wissing, E.; Zoutberg, M.C.; Stam, C.H.

    1990-01-01

    Several new organo-platinum(II) and -palladium(II) complexes [MX(C{6}H{3}{CH{2}NR}1{R}2{}{2}-2, 6)] (X = halide, M = Pt, Pd; R}1{ = R}2{ = Et; R}2{ = Me, R}1{ = }t{Bu, M = Pt: R}2{ = Me, R}1{ = Ph) have been synthesized from [PtCl{2}(SEt{2}){2}] or [PdCl{2}(COD)] (COD = 1, 5-cyclooctadiene) by react

  19. Platinum-induced neurotoxicity: A review of possible mechanisms.

    Science.gov (United States)

    Kanat, Ozkan; Ertas, Hulya; Caner, Burcu

    2017-08-10

    Patients treated with platinum-based chemotherapy frequently experience neurotoxic symptoms, which may lead to premature discontinuation of therapy. Despite discontinuation of platinum drugs, these symptoms can persist over a long period of time. Cisplatin and oxaliplatin, among all platinum drugs, have significant neurotoxic potential. A distal dose-dependent symmetrical sensory neuropathy is the most common presentation of platinum neurotoxicity. DNA damage-induced apoptosis of dorsal root ganglion (DRG) neurons seems to be the principal cause of neurological symptoms. However, DRG injury alone cannot explain some unique symptoms such as cold-aggravated burning pain affecting distal extremities that is observed with oxaliplatin administration. In this article, we briefly reviewed potential mechanisms for the development of platinum drugs-associated neurological manifestations.

  20. Under-Reported Aspects of Platinum Drug Pharmacology

    Directory of Open Access Journals (Sweden)

    Dirk Theile

    2017-02-01

    Full Text Available Platinum drugs remain the backbone of many antineoplastic regimens. Among the numerous chemical or pharmacological effects of platinum drugs, some aspects tend to be under-reported. Thus, this perspective paper intends to stress some neglected properties of platinum drugs: first, the physico-chemical characteristics (aquation reaction kinetics that determine site-specific toxicity; second, the impact on RNA molecules. Knowledge of the ‘RNA world’ has dramatically changed our understanding of cellular and molecular biology. The inherent RNA-crosslinking properties should make platinum-based drugs interact with coding and non-coding RNAs. Third, we will discuss the impact on the immune system, which is now recognized to substantially contribute to chemotherapy efficacy. Together, platinum drugs are in fact old drugs, but are worth re-focusing on. Many aspects are still mysterious but can pave the way to new drugs or an improved application of the already existing compounds.

  1. Sulfur hexafluoride (SF6) emission estimates for China: an inventory for 1990-2010 and a projection to 2020.

    Science.gov (United States)

    Fang, Xuekun; Hu, Xia; Janssens-Maenhout, Greet; Wu, Jing; Han, Jiarui; Su, Shenshen; Zhang, Jianbo; Hu, Jianxin

    2013-04-16

    Sulfur hexafluoride (SF6) is the most potent greenhouse gas regulated under the Kyoto Protocol, with a high global warming potential. In this study, SF6 emissions from China were inventoried for 1990-2010 and projected to 2020. Results reveal that the highest SF6 emission contribution originates from the electrical equipment sector (about 70%), followed by the magnesium production sector, the semiconductor manufacture sector and the SF6 production sector (each about 10%). Both agreements and discrepancies were found in comparisons of our estimates with previously published data. An accelerated growth rate was found for Chinese SF6 emissions during 1990-2010. Because the relative growth rate of SF6 emissions is estimated to be much higher than those of CO2, CH4, and N2O, SF6 will play an increasing role in greenhouse gas emissions in China. Global contributions from China increased rapidly from 0.9 ± 0.3% in 1990 to 22.8 ± 6.3% in 2008, making China one of the crucial contributors to the recent growth in global emissions. Under the examined Business-as-usual (BAU) Scenario, projected emissions will reach 4270 ± 1020 t in 2020, but a reduction of about 90% of the projected BAU emissions would be obtained under the Alternative Scenario.

  2. Standard test method for isotopic analysis of uranium hexafluoride by double standard single-collector gas mass spectrometer method

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This is a quantitative test method applicable to determining the mass percent of uranium isotopes in uranium hexafluoride (UF6) samples with 235U concentrations between 0.1 and 5.0 mass %. 1.2 This test method may be applicable for the entire range of 235U concentrations for which adequate standards are available. 1.3 This test method is for analysis by a gas magnetic sector mass spectrometer with a single collector using interpolation to determine the isotopic concentration of an unknown sample between two characterized UF6 standards. 1.4 This test method is to replace the existing test method currently published in Test Methods C761 and is used in the nuclear fuel cycle for UF6 isotopic analyses. 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro...

  3. Standard test method for isotopic analysis of hydrolyzed uranium hexafluoride and uranyl nitrate solutions by thermal ionization mass spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This method applies to the determination of isotopic composition in hydrolyzed nuclear grade uranium hexafluoride. It covers isotopic abundance of 235U between 0.1 and 5.0 % mass fraction, abundance of 234U between 0.0055 and 0.05 % mass fraction, and abundance of 236U between 0.0003 and 0.5 % mass fraction. This test method may be applicable to other isotopic abundance providing that corresponding standards are available. 1.2 This test method can apply to uranyl nitrate solutions. This can be achieved either by transforming the uranyl nitrate solution to a uranyl fluoride solution prior to the deposition on the filaments or directly by depositing the uranyl nitrate solution on the filaments. In the latter case, a calibration with uranyl nitrate standards must be performed. 1.3 This test method can also apply to other nuclear grade matrices (for example, uranium oxides) by providing a chemical transformation to uranyl fluoride or uranyl nitrate solution. 1.4 This standard does not purport to address al...

  4. Standard test method for gamma energy emission from fission products in uranium hexafluoride and uranyl nitrate solution

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This test method covers the measurement of gamma energy emitted from fission products in uranium hexafluoride (UF6) and uranyl nitrate solution. It is intended to provide a method for demonstrating compliance with UF6 specifications C 787 and C 996 and uranyl nitrate specification C 788. 1.2 The lower limit of detection is 5000 MeV Bq/kg (MeV/kg per second) of uranium and is the square root of the sum of the squares of the individual reporting limits of the nuclides to be measured. The limit of detection was determined on a pure, aged natural uranium (ANU) solution. The value is dependent upon detector efficiency and background. 1.3 The nuclides to be measured are106Ru/ 106Rh, 103Ru,137Cs, 144Ce, 144Pr, 141Ce, 95Zr, 95Nb, and 125Sb. Other gamma energy-emitting fission nuclides present in the spectrum at detectable levels should be identified and quantified as required by the data quality objectives. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its us...

  5. Spectroscopy of hexafluorides with an odd number of electrons; Spectroscopie des hexafluorures a nombre impair d'electrons

    Energy Technology Data Exchange (ETDEWEB)

    Boudon, V

    1995-05-01

    From a theoretical point of view, a tensorial formalism adapted to the study of molecules or octahedral ions with a half-integer angular momentum has been developed for the first time. We have used here the method of projective representations, more consistent than that of double groups. A complete set of coupling coefficients and formulas, as well as the corresponding computing programs have been elaborated. This has firstly allowed us to write a simple model describing the vibronic structure of colored hexafluorides. Then, some applications of this formalism to the study of ro-vibronic couplings of XY{sub 6} molecules in a fourfold degenerate electronic state have been considered, especially concerning operators associated to dynamic Jahn-Teller effect. From an experimental point of view, we have considered IrF{sub 6}, for which we have mastered the synthesis, purification and conservation processes. A first study at low resolution (absorption and Raman scattering) has been performed for this molecule. We have then set up two high resolution spectroscopic devices in the visible region (saturated absorption - tested with an iodine cell- and simple absorption with multiple pass). These especially use a dye laser. They should now allow the spectroscopy of the visible band of IrF{sub 6} in order to resolve for the first time its fine rotational structure. (author)

  6. Uniform deposition of uranium hexafluoride (UF6): Standardized mass deposits and controlled isotopic ratios using a thermal fluorination method

    Energy Technology Data Exchange (ETDEWEB)

    McNamara, Bruce K.; O’Hara, Matthew J.; Casella, Andrew M.; Carter, Jennifer C.; Addleman, R. Shane; MacFarlan, Paul J.

    2016-07-01

    Abstract: We report a convenient method for the generation of volatile uranium hexafluoride (UF6) from solid uranium oxides and other uranium compounds, followed by uniform deposition of low levels of UF6 onto sampling coupons. Under laminar flow conditions, UF6 is shown to interact with surfaces within the chamber to a highly predictable degree. We demonstrate the preparation of uranium deposits that range between ~0.01 and 470±34 ng∙cm-2. The data suggest the method can be extended to creating depositions at the sub-picogram∙cm-2 level. Additionally, the isotopic composition of the deposits can be customized by selection of the uranium source materials. We demonstrate a layering technique whereby two uranium solids, each with a different isotopic composition, are employed to form successive layers of UF6 on a surface. The result is an ultra-thin deposit of UF6 that bears an isotopic signature that is a composite of the two uranium sources. The reported deposition method has direct application to the development of unique analytical standards for nuclear safeguards and forensics.

  7. Effect of air and sulfur hexafluoride (SF6) tamponade on visual acuity after epiretinal membrane surgery: a pilot study.

    Science.gov (United States)

    Chabot, Guillaume; Bourgault, Serge; Cinq-Mars, Benoit; Tourville, Éric; Caissie, Mathieu

    2017-06-01

    The aim of this study was to compare visual acuity improvement after epiretinal membrane (ERM) surgery using air and sulfur hexafluoride (SF6) tamponade. Secondary objectives were to evaluate Visual Function Questionnaire (VFQ) scores and central retinal thickness (CRT) changes. This was a prospective, randomized study. Thirty-two patients were prospectively randomized, 19 to the air group and 13 to the SF6 group. This study has enrolled patients with ERM from clinical practice of 4 vitreoretinal surgeons. Preoperative and postoperative data included best-corrected visual acuity (BCVA) with the use of the Early Treatment Diabetic Retinopathy Study (ETDRS) chart, VFQ scores, CRT, and cataract staging. Pars plana vitrectomy with ERM peeling was performed on all patients, either with partial air tamponade or with complete SF6 tamponade. Mean BCVA improved by 0.07 logMAR (3.5 ETDRS letters) in the air group and by 0.09 logMAR (4.5 ETDRS letters) in the SF6 group (p = 0.58). There was no statistically significant difference between the groups with regard to BCVA, VFQ scores, and CRT. The groups had similar rates of cataract progression and adverse events. ERM peeling with partial air tamponade or with complete SF6 tamponade have similar outcomes in terms of BCVA, VFQ scores, CRT, cataract development, and adverse events. Copyright © 2017 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

  8. A Peer Review of the Strategy for Characterizing Ransuranics and Technetium Contamination in Uranium Hexafluoride Tails Cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Sengupta, S.K.; Randich, E.; Avci, H.I.; Steindler, M.J.; Brumburgh, G.P.

    2000-09-01

    This document provides the findings from a peer review of the Oak Ridge National Laboratory (ORNL) Hightower 2000 study, which set forth a strategy for characterization of low levels of radioactive contaminants in depleted uranium hexafluoride (DUF{sub 6}) cylinders at the Oak Ridge, Paducah, and Portsmouth gaseous diffusion plants. The information from that study will be used in a DOE-issued request for proposal (RFP) for conversion services from the private sector, to assist vendors in reducing costs associated with contingencies relating to handling this DUF{sub 6} with elevated transuranics (TRUs) and technetium (Tc). The Hightower study developed a general strategy for DUF{sub 6} sampling and analysis in accordance with their task but also recommended the following courses of action: (a) Collect and analyze liquid samples from the two identified Paducah Gaseous Diffusion Plant (PGDP) feed cylinders, feed the DUF{sub 6} into the cascades, and conduct an analysis on the resulting heels by washing and analyzing the wash rinsate; (b) Characterize the cylinder coatings to determine the extent and levels of polychlorinated biphenyl (PCB) contamination; and (c) Verify the characterization of the cylinder inventory's compliance with Department of Transportation (DOT) regulations and the American Society of Mechanical Engineers (ASME) pressure vessel code In addition to the above recommendations, the study also concluded that additional characterization is not likely to result in lower bids by prospective vendors, and that direct sampling of many older tails cylinders may be impractical.

  9. Uniform deposition of uranium hexafluoride (UF6): Standardized mass deposits and controlled isotopic ratios using a thermal fluorination method.

    Science.gov (United States)

    McNamara, Bruce K; O'Hara, Matthew J; Casella, Andrew M; Carter, Jennifer C; Addleman, R Shane; MacFarlan, Paul J

    2016-07-01

    We report a convenient method for the generation of volatile uranium hexafluoride (UF6) from solid uranium oxides and other U compounds, followed by uniform deposition of low levels of UF6 onto sampling coupons. Under laminar flow conditions, UF6 is shown to interact with surfaces within a fixed reactor geometry to a highly predictable degree. We demonstrate the preparation of U deposits that range between approximately 0.01 and 500ngcm(-2). The data suggest the method can be extended to creating depositions at the sub-picogramcm(-2) level. The isotopic composition of the deposits can be customized by selection of the U source materials and we demonstrate a layering technique whereby two U solids, each with a different isotopic composition, are employed to form successive layers of UF6 on a surface. The result is an ultra-thin deposit that bears an isotopic signature that is a composite of the two U sources. The reported deposition method has direct application to the development of unique analytical standards for nuclear safeguards and forensics. Further, the method allows access to very low atomic or molecular coverages of surfaces.

  10. REAC/TS Radiation Accident Registry: An Overview

    Energy Technology Data Exchange (ETDEWEB)

    Doran M. Christensen, DO, REAC/TS Associate Director and Staff Physician Becky Murdock, REAC/TS Registry and Health Physics Technician

    2012-12-12

    Over the past four years, REAC/TS has presented a number of case reports from its Radiation Accident Registry. Victims of radiological or nuclear incidents must meet certain dose criteria for an incident to be categorized as an “accident” and be included in the registry. Although the greatest numbers of “accidents” in the United States that have been entered into the registry involve radiation devices, the greater percentage of serious accidents have involved sealed sources of one kind or another. But if one looks at the kinds of accident scenarios that have resulted in extreme consequence, i.e., death, the greater share of deaths has occurred in medical settings.

  11. Reacting chemistry at the air-water interface

    Science.gov (United States)

    Murakami, Tomoyuki; Morgan, Thomas; Huwel, Lutz; Graham, William

    2016-09-01

    Plasma interaction with gas-liquid interfaces is becoming increasingly important in biological applications, chemical analysis and medicine. It introduces electrons, new ionic species and reactive species and contributes to chemical and electrical self-organization at the interface. To provide insight into the associated physics and chemistry at work in the evolution of the plasma in the air-water interface (AWI), a time-dependent one-dimensional modelling has been developed. The numerical simulation is used to solve the kinetic equations and help identify the important reaction mechanisms and describe the phenomena associated with hundreds of reacting pathways in gas-phase and liquid-phase AWI chemistry. This work was partly supported by JSPS KAKENHI Grant Number 16K04998.

  12. Toward parallel, adaptive mesh refinement for chemically reacting flow simulations

    Energy Technology Data Exchange (ETDEWEB)

    Devine, K.D.; Shadid, J.N.; Salinger, A.G. Hutchinson, S.A. [Sandia National Labs., Albuquerque, NM (United States); Hennigan, G.L. [New Mexico State Univ., Las Cruces, NM (United States)

    1997-12-01

    Adaptive numerical methods offer greater efficiency than traditional numerical methods by concentrating computational effort in regions of the problem domain where the solution is difficult to obtain. In this paper, the authors describe progress toward adding mesh refinement to MPSalsa, a computer program developed at Sandia National laboratories to solve coupled three-dimensional fluid flow and detailed reaction chemistry systems for modeling chemically reacting flow on large-scale parallel computers. Data structures that support refinement and dynamic load-balancing are discussed. Results using uniform refinement with mesh sequencing to improve convergence to steady-state solutions are also presented. Three examples are presented: a lid driven cavity, a thermal convection flow, and a tilted chemical vapor deposition reactor.

  13. 3D Reacting Flow Analysis of LANTR Nozzles

    Science.gov (United States)

    Stewart, Mark E. M.; Krivanek, Thomas M.; Hemminger, Joseph A.; Bulman, M. J.

    2006-01-01

    This paper presents performance predictions for LANTR nozzles and the system implications for their use in a manned Mars mission. The LANTR concept is rocket thrust augmentation by injecting Oxygen into the nozzle to combust the Hydrogen exhaust of a Nuclear Thermal Rocket. The performance predictions are based on three-dimensional reacting flow simulations using VULCAN. These simulations explore a range of O2/H2 mixture ratios, injector configurations, and concepts. These performance predictions are used for a trade analysis within a system study for a manned Mars mission. Results indicate that the greatest benefit of LANTR will occur with In-Situ Resource Utilization (ISRU). However, Hydrogen propellant volume reductions may allow greater margins for fitting tanks within the launch vehicle where packaging issues occur.

  14. Monofunctional and Higher-Valent Platinum Anticancer Agents

    Science.gov (United States)

    Johnstone, Timothy C.; Wilson, Justin J.

    2013-01-01

    Platinum compounds represent one of the great success stories of metals in medicine. Following the serendipitous discovery of the anticancer activity of cisplatin by Rosenberg, a large number of cisplatin variants have been prepared and tested for their ability to kill cancer cells and inhibit tumor growth. These efforts continue today with increased realization that new strategies are needed to overcome issues of toxicity and resistance inherent to treatment by the approved platinum anticancer agents. One approach has been the use of so-called “non-traditional” platinum(II) and platinum(IV) compounds that violate the structure-activity relationships that governed platinum drug-development research for many years. Another is the use of specialized drug delivery strategies. Here we describe recent developments from our laboratory involving monofunctional platinum(II) complexes together with an historical account of the manner by which we came to investigate these compounds and their relationship to previously studied molecules. We also discuss work carried out using platinum(IV) prodrugs and the development of nanoconstructs designed to deliver them in vivo. PMID:23738524

  15. Surface Analysis of 4-Aminothiophenol Adsorption at Polycrystalline Platinum Electrodes

    Science.gov (United States)

    Rosario-Castro, Belinda I.; Fachini, Estevao R.; Contes, Enid J.; Perez-Davis, Marla E.; Cabrera, Carlos R.

    2008-01-01

    Formation of self-assembled monolayer (SAM) of 4-aminothiophenol (4-ATP) on polycrystalline platinum electrodes has been studied by surface analysis and electrochemistry techniques. The 4-ATP monolayer was characterized by cyclic voltammetry (CV), Raman spectroscopy, reflection absorption infrared (RAIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Cyclic voltammetry (CV) experiments give an idea about the packing quality of the monolayer. RAIR and Raman spectra for 4-ATP modified platinum electrodes showed the characteristic adsorption bands for neat 4-ATP indicating the adsorption of 4-ATP molecules on platinum surface. The adsorption on platinum was also evidenced by the presence of sulfur and nitrogen peaks by XPS survey spectra of the modified platinum electrodes. High resolution XPS studies and RAIR spectrum for platinum electrodes modified with 4-ATP indicate that molecules are sulfur-bonded to the platinum surface. The formation of S-Pt bond suggests that ATP adsorption gives up an amino terminated SAM. Thickness of the monolayer was evaluated via angle-resolved XPS (AR-XPS) analyses. Derivatization of 4-ATP SAM was performed using 16-Br hexadecanoic acid.

  16. Cisplatin and platinum drugs at the molecular level. (Review).

    Science.gov (United States)

    Boulikas, Teni; Vougiouka, Maria

    2003-01-01

    Over twenty years of intensive work toward improvement of cisplatin, and with hundreds of platinum drugs tested, has resulted in the introduction of the widely used carboplatin and of oxaliplatin used only for a very narrow spectrum of cancers. A number of interesting platinum compounds including the orally administered platinum drug JM216, nedaplatin, the sterically hindered platinum(II) complex ZD0473, the trinuclear platinum complex BBR3464, and the liposomal forms Lipoplatin and SPI-77 are under clinical evaluation. This review summarizes the molecular mechanisms of platinum compounds for DNA damage, DNA repair and induction of apoptosis via activation or modulation of signaling pathways and explores the basis of platinum resistance. Cisplatin, carboplatin, oxaliplatin and most other platinum compounds induce damage to tumors via induction of apoptosis; this is mediated by activation of signal transduction leading to the death receptor mechanisms as well as mitochondrial pathways. Apoptosis is responsible for the characteristic nephrotoxicity, ototoxicity and most other toxicities of the drugs. The major limitation in the clinical applications of cisplatin has been the development of cisplatin resistance by tumors. Mechanisms explaining cisplatin resistance include the reduction in cisplatin accumulation inside cancer cells because of barriers across the cell membrane, the faster repair of cisplatin adducts, the modulation of apoptotic pathways in various cells, the upregulation in transcription factors, the loss of p53 and other protein functions and a higher concentration of glutathione and metallothioneins in some type of tumors. A number of experimental strategies to overcome cisplatin resistance are at the preclinical or clinical level such as introduction of the bax gene, inhibition of the JNK pathway, introduction of a functional p53 gene, treatment of tumors with aldose reductase inhibitors and others. Particularly important are combinations of platinum

  17. Bio-inspired routes for synthesizing efficient nanoscale platinum electrocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Jennifer N. [Univ. of California, San Diego, CA (United States); Wang, Joseph [Univ. of California, San Diego, CA (United States)

    2014-08-31

    The overall objective of the proposed research is to use fundamental advances in bionanotechnology to design powerful platinum nanocrystal electrocatalysts for fuel cell applications. The new economically-viable, environmentally-friendly, bottom-up biochemical synthetic strategy will produce platinum nanocrystals with tailored size, shape and crystal orientation, hence leading to a maximum electrochemical reactivity. There are five specific aims to the proposed bio-inspired strategy for synthesizing efficient electrocatalytic platinum nanocrystals: (1) isolate peptides that both selectively bind particular crystal faces of platinum and promote the nucleation and growth of particular nanocrystal morphologies, (2) pattern nanoscale 2-dimensional arrays of platinum nucleating peptides from DNA scaffolds, (3) investigate the combined use of substrate patterned peptides and soluble peptides on nanocrystal morphology and growth (4) synthesize platinum crystals on planar and large-area carbon electrode supports, and (5) perform detailed characterization of the electrocatalytic behavior as a function of catalyst size, shape and morphology. Project Description and Impact: This bio-inspired collaborative research effort will address key challenges in designing powerful electrocatalysts for fuel cell applications by employing nucleic acid scaffolds in combination with peptides to perform specific, environmentally-friendly, simultaneous bottom-up biochemical synthesis and patterned assembly of highly uniform and efficient platinum nanocrystal catalysts. Bulk synthesis of nanoparticles usually produces a range of sizes, accessible catalytic sites, crystal morphologies, and orientations, all of which lead to inconsistent catalytic activities. In contrast, biological systems routinely demonstrate exquisite control over inorganic syntheses at neutral pH and ambient temperature and pressures. Because the orientation and arrangement of the templating biomolecules can be precisely

  18. The RSC Faraday prize lecture of 1989 on platinum.

    Science.gov (United States)

    Thomas, John Meurig

    2017-08-25

    In 1861, Michael Faraday gave one of his last Friday Evening Discourses at the Royal Institution of Great Britain, London, on platinum, which he described as "this beautiful, magnificent and valuable metal". More than a hundred and twenty years later (in 1989), the author re-enacted, at the Royal Institution, many of the demonstrations that Faraday carried out in his memorable Discourse. This article outlines many of Faraday's views on, and experiments with, platinum. It also describes the continuing importance and utilization of platinum, both as perceived in 1989 and from present perspectives.

  19. New Perfluorophtalate Complexes of Platinum(II) With Chemotherapeutic Potential

    OpenAIRE

    de Oliveira, M. B.; J. Miller; Banks, R. E.; Kelland, L R; McAuliffe, C. A.; Mahmood, N; Rowland, I. J.

    1996-01-01

    Two new platinum(II) complexes have been synthesized and their anti-tumour and anti-HIV activities have been evaluated. The new complexes are: (i) cis-tetrafluorophthalate-ammine-morpholine-platinum(II) or MMF3 and (ii) cis-tetrafluorophthalate- ammine-piperidine-platinum(II) or MPF4. They were characterized by elemental analysis, IR spectra and 1H and 13C NMR spectra. They were tested against five human ovarian carcinoma cell lines, viz., CH1, CH1cisR, A2780, A2780cisR and SKOV-3. They were ...

  20. Study of supported platinum catalysts by anomalous scattering

    Energy Technology Data Exchange (ETDEWEB)

    Georgopoulos, P.; Cohen, J.B.

    1985-01-01

    Platinum metal catalysts supported on silica gel and alumina were examined by wide-angle anomalous x-ray scattering at the Cornell High Energy Synchrotron Source. Complete removal of the support background features is achieved by this method, eliminating errors due to inaccurate background estimation. Platinum diffraction patterns from very-high-percentage metal-exposed catalysts were obtained for the first time, as well as from platinum supported on alumina. This technique is suitable for examining catalysts under working conditions and is superior to EXAFS for determinations of particle morphology and size distribution. 10 references, 8 figures.

  1. Interaction of novel bis(platinum) complexes with DNA.

    OpenAIRE

    Roberts, J D; Van Houten, B; Qu, Y; Farrell, N P

    1989-01-01

    Bis(platinum) complexes [[cis-PtCl2(NH3)]2H2N(CH2)nNH2] are a novel series of potential anticancer agents in which two cis-diamine(platinum) groups are linked by an alkyldiamine of variable length. These complexes are potentially tetrafunctional, a unique feature in comparison with known anticancer agents. Studies of DNA interactions of bis(platinum) complexes in comparison with cisplatin demonstrate significant differences. Investigations of interstrand crosslink formation in which crosslink...

  2. Platinum(II) and platinum(IV) complexes stabilized by abnormal/mesoionic C4-bound dicarbenes.

    Science.gov (United States)

    Khlebnikov, Vsevolod; Heckenroth, Marion; Müller-Bunz, Helge; Albrecht, Martin

    2013-03-28

    Platinum(II) complexes comprising abnormal diimidazolylidene ligands were synthesized from cis-PtMe(2)(DMSO)(2) using microwave-assisted double C-H bond activation. NMR analysis revealed an unusual solvolysis process, induced by coordinating solvents such as DMSO and MeCN, which has not been observed in related normal dicarbene complexes. NMR and IR spectroscopy and crystallographic analysis of the mono-substituted DMSO complex indicate a sulfur-bonding of the DMSO ligand to the platinum(II) center. Analysis of the DMSO exchange kinetics provided for the first time a quantitative measure of the trans effect of abnormal carbene ligands. The kinetic exchange rate in these bidentate abnormal dicarbene complexes is 0.050(±2) s(-1) and thus similar to analogous platinum(II) complexes containing phenylpyridine, yet significantly slower than that induced by pyridylidene pyridine. Reaction of the dicarbene platinum(II) complexes with PhICl(2), Br(2) and I(2) afforded the corresponding platinum(IV) complexes. Linkage isomerism of the Pt(IV)-bound DMSO was observed when the bromination reaction was performed in DMSO solution. Moreover, solvolysis was less pronounced in the platinum(IV) complexes than in the corresponding platinum(II) analogues.

  3. Teens impulsively react rather than retreat from threat.

    Science.gov (United States)

    Dreyfuss, Michael; Caudle, Kristina; Drysdale, Andrew T; Johnston, Natalie E; Cohen, Alexandra O; Somerville, Leah H; Galván, Adriana; Tottenham, Nim; Hare, Todd A; Casey, B J

    2014-01-01

    There is a significant inflection in risk taking and criminal behavior during adolescence, but the basis for this increase remains largely unknown. An increased sensitivity to rewards has been suggested to explain these behaviors, yet juvenile offences often occur in emotionally charged situations of negative valence. How behavior is altered by changes in negative emotional processes during adolescence has received less attention than changes in positive emotional processes. The current study uses a measure of impulsivity in combination with cues that signal threat or safety to assess developmental changes in emotional responses to threat cues. We show that adolescents, especially males, impulsively react to threat cues relative to neutral ones more than adults or children, even when instructed not to respond. This adolescent-specific behavioral pattern is paralleled by enhanced activity in limbic cortical regions implicated in the detection and assignment of emotional value to inputs and in the subsequent regulation of responses to them when successfully suppressing impulsive responses to threat cues. In contrast, prefrontal control regions implicated in detecting and resolving competing responses show an adolescent-emergent pattern (i.e. greater activity in adolescents and adults relative to children) during successful suppression of a response regardless of emotion. Our findings suggest that adolescence is a period of heightened sensitivity to social and emotional cues that results in diminished regulation of behavior in their presence. © 2014 S. Karger AG, Basel.

  4. Numerical Investigation of a Statistically Stationary Turbulent Reacting Flow

    Science.gov (United States)

    Overholt, Matthew R.; Pope, Stephen B.

    1997-11-01

    Direct numerical simulation (DNS) has been very useful in the study of inert scalar mixing in turbulent flows, and has recently become feasible for studies of reacting scalars. We have formulated an accessible inhomogeneous nonpremixed turbulent reactive flow for investigating the effects of mixing on reaction and testing mixing models. The mixture fraction-progress variable approach is used with a model single-step reversible finite-rate thermochemistry, yielding non-trivial stationary solutions corresponding to stable reaction and allowing local extinction to occur. A mean gradient in the mixture fraction gives rise to stationarity without forcing, as well as a flame brush. A range of reaction zone thicknesses and Damkohler numbers are examined, yielding a broad spectrum of behavior, ranging from thick to thin flames, and from local extinction to near equilibrium. Based on this study results from full probability density function (PDF) simulations using the IEM and EMST mixing models are evaluated. Conditional moment closure (CMC) results are evaluated as well.

  5. Adjoint based sensitivity analysis of a reacting jet in crossflow

    Science.gov (United States)

    Sashittal, Palash; Sayadi, Taraneh; Schmid, Peter

    2016-11-01

    With current advances in computational resources, high fidelity simulations of reactive flows are increasingly being used as predictive tools in various industrial applications. In order to capture the combustion process accurately, detailed/reduced chemical mechanisms are employed, which in turn rely on various model parameters. Therefore, it would be of great interest to quantify the sensitivities of the predictions with respect to the introduced models. Due to the high dimensionality of the parameter space, methods such as finite differences which rely on multiple forward simulations prove to be very costly and adjoint based techniques are a suitable alternative. The complex nature of the governing equations, however, renders an efficient strategy in finding the adjoint equations a challenging task. In this study, we employ the modular approach of Fosas de Pando et al. (2012), to build a discrete adjoint framework applied to a reacting jet in crossflow. The developed framework is then used to extract the sensitivity of the integrated heat release with respect to the existing combustion parameters. Analyzing the sensitivities in the three-dimensional domain provides insight towards the specific regions of the flow that are more susceptible to the choice of the model.

  6. Dynamic Load Balancing Strategies for Parallel Reacting Flow Simulations

    Science.gov (United States)

    Pisciuneri, Patrick; Meneses, Esteban; Givi, Peyman

    2014-11-01

    Load balancing in parallel computing aims at distributing the work as evenly as possible among the processors. This is a critical issue in the performance of parallel, time accurate, flow simulators. The constraint of time accuracy requires that all processes must be finished with their calculation for a given time step before any process can begin calculation of the next time step. Thus, an irregularly balanced compute load will result in idle time for many processes for each iteration and thus increased walltimes for calculations. Two existing, dynamic load balancing approaches are applied to the simplified case of a partially stirred reactor for methane combustion. The first is Zoltan, a parallel partitioning, load balancing, and data management library developed at the Sandia National Laboratories. The second is Charm++, which is its own machine independent parallel programming system developed at the University of Illinois at Urbana-Champaign. The performance of these two approaches is compared, and the prospects for their application to full 3D, reacting flow solvers is assessed.

  7. 9519 biotite granodiorite reacted in a temperature gradient

    Energy Technology Data Exchange (ETDEWEB)

    Charles, R.W.; Bayhurst, G.K.

    1980-10-01

    A biotite granodiorite from the Fenton Hill Hot Dry Rock (HDR) geothermal system was reacted in a controlled temperature gradient with initially distilled water for 60d. Polished rock prisms were located in the gradient at 72, 119, 161, 209, 270, and 310/sup 0/C. Scanning electron microscope and microprobe analyses show the appearance of secondary phases: Ca-montmorillonite at 72/sup 0/C and 119/sup 0/C; zeolite, either stilbite or heulandite, at 161/sup 0/C; and another zeolite, thomsonite, at higher temperatures. Solution analyses show a steady state equilibrium exists between solution and overgrowths after about 2 weeks of reaction. The chemographic relations for the system are explored in some detail indicating the divariant assemblages may be placed in a reasonable sequence in intensive variable space. These relations predict high and low temperature effects not directly observed experimentally as well as relevant univariant equilibria. Solution chemistry indicates the Na-Ca-K geothermometer more adequately predicts temperature in this system than does the silica geothermometer.

  8. CERN reacts to increased costs to completion of the LHC

    CERN Document Server

    2002-01-01

    Aspects of LHC construction. The CERN Council, where the representatives of the 20 Member States of the Organization decide on scientific programmes and financial resources, held its 120th session on 14 December under the chairmanship of Prof. Maurice Bourquin (CH). CERN adjusts to the LHC Director-General, Luciano Maiani, stressed that CERN was now fully engaged in the LHC and outlined the first moves to react to the increased cost to completion of the LHC. The new accelerator is an extremely complex, high-tech project which CERN is building under very severe conditions. However, the technical challenges are solved and industrial production of accelerator elements, and installation are starting. Professor Maiani said that 2001 had been a very hard but decisive year for CERN. An important milestone had been passed during this meeting with the approval of the LHC dipole magnets contract, the last major contract for the accelerator. The new costs to completion of the LHC project are now clear. A first propos...

  9. E platinum, a newly synthesized platinum compound, induces apoptosis through ROS-triggered ER stress in gastric carcinoma cells.

    Science.gov (United States)

    Wang, Xiaoping; Guo, Qinglong; Tao, Lei; Zhao, Li; Chen, Yan; An, Teng; Chen, Zhen; Fu, Rong

    2017-01-01

    Gastric cancer (GC) is still one of the leading causes of death in cancer-related diseases. In this study, we aimed to investigate the antitumor effect of E Platinum, a newly platinum-based chemotherapeutic agent bearing the basic structure of Oxaliplatin, in a variety of gastric carcinoma cells and the underlying mechanisms. We demonstrated that E Platinum significantly induced apoptosis in gastric cancer cells via mitochondrial apoptotic pathway as a result of increased reactive oxygen species (ROS). We also found that E Platinum enhanced Ca(2+) flux out from the endoplasmic reticulum by increasing the protein expression of IP3R type 1 (IP3R1) and decreasing the expression of ERp44. Dysfunction of Ca(2+) homeostasis in endoplasmic reticulum (ER) leads to accumulation of unfolded proteins and ER stress. Mechanically, E Platinum increased ER stress associated protein expression such as GRP78, p-PERK, p-eIF2α, ATF4, and CHOP. However, knocking down CHOP reversed E Platinum-induced apoptosis by blocking mitochondrial apoptotic pathway. Furthermore, 10 mg/kg of E Platinum significantly suppressed BGC-823 tumor growth in vivo without toxicity, which correlated with induction of apoptosis and expression of ER stress related proteins in tumor tissues. Taken together, E Platinum inhibited tumor growth and induced apoptosis by ROS-mediated ER stress activation both in vitro and in vivo. Our study indicated that E Platinum may be a potential and effective treatment for gastric cancer in clinical. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  10. Determination of the atmospheric lifetime and global warming potential of sulfur hexafluoride using a three-dimensional model

    Science.gov (United States)

    Kovács, Tamás; Feng, Wuhu; Totterdill, Anna; Plane, John M. C.; Dhomse, Sandip; Gómez-Martín, Juan Carlos; Stiller, Gabriele P.; Haenel, Florian J.; Smith, Christopher; Forster, Piers M.; García, Rolando R.; Marsh, Daniel R.; Chipperfield, Martyn P.

    2017-01-01

    We have used the Whole Atmosphere Community Climate Model (WACCM), with an updated treatment of loss processes, to determine the atmospheric lifetime of sulfur hexafluoride (SF6). The model includes the following SF6 removal processes: photolysis, electron attachment and reaction with mesospheric metal atoms. The Sodankylä Ion Chemistry (SIC) model is incorporated into the standard version of WACCM to produce a new version with a detailed D region ion chemistry with cluster ions and negative ions. This is used to determine a latitude- and altitude-dependent scaling factor for the electron density in the standard WACCM in order to carry out multi-year SF6 simulations. The model gives a mean SF6 lifetime over an 11-year solar cycle (τ) of 1278 years (with a range from 1120 to 1475 years), which is much shorter than the currently widely used value of 3200 years, due to the larger contribution (97.4 %) of the modelled electron density to the total atmospheric loss. The loss of SF6 by reaction with mesospheric metal atoms (Na and K) is far too slow to affect the lifetime. We investigate how this shorter atmospheric lifetime impacts the use of SF6 to derive stratospheric age of air. The age of air derived from this shorter lifetime SF6 tracer is longer by 9 % in polar latitudes at 20 km compared to a passive SF6 tracer. We also present laboratory measurements of the infrared spectrum of SF6 and find good agreement with previous studies. We calculate the resulting radiative forcings and efficiencies to be, on average, very similar to those reported previously. Our values for the 20-, 100- and 500-year global warming potentials are 18 000, 23 800 and 31 300, respectively.

  11. Effect of sulfur hexafluoride gas and post-annealing treatment for inductively coupled plasma etched barium titanate thin films

    Science.gov (United States)

    2014-01-01

    Aerosol deposition- (AD) derived barium titanate (BTO) micropatterns are etched via SF6/O2/Ar plasmas using inductively coupled plasma (ICP) etching technology. The reaction mechanisms of the sulfur hexafluoride on BTO thin films and the effects of annealing treatment are verified through X-ray photoelectron spectroscopy (XPS) analysis, which confirms the accumulation of reaction products on the etched surface due to the low volatility of the reaction products, such as Ba and Ti fluorides, and these residues could be completely removed by the post-annealing treatment. The exact peak positions and chemicals shifts of Ba 3d, Ti 2p, O 1 s, and F 1 s are deduced by fitting the XPS narrow-scan spectra on as-deposited, etched, and post-annealed BTO surfaces. Compared to the as-deposited BTOs, the etched Ba 3d 5/2 , Ba 3d 3/2 , Ti 2p 3/2 , Ti 2p 1/2 , and O 1 s peaks shift towards higher binding energy regions by amounts of 0.55, 0.45, 0.4, 0.35, and 0.85 eV, respectively. A comparison of the as-deposited film with the post-annealed film after etching revealed that there are no significant differences in the fitted XPS narrow-scan spectra except for the slight chemical shift in the O 1 s peak due to the oxygen vacancy compensation in O2-excessive atmosphere. It is inferred that the electrical properties of the etched BTO film can be restored by post-annealing treatment after the etching process. Moreover, the relative permittivity and loss tangent of the post-annealed BTO thin films are remarkably improved by 232% and 2,695%, respectively. PMID:25249824

  12. Gas Sensing Analysis of Ag-Decorated Graphene for Sulfur Hexafluoride Decomposition Products Based on the Density Functional Theory

    Science.gov (United States)

    Zhang, Xiaoxing; Huang, Rong; Gui, Yingang; Zeng, Hong

    2016-01-01

    Detection of decomposition products of sulfur hexafluoride (SF6) is one of the best ways to diagnose early latent insulation faults in gas-insulated equipment, and the occurrence of sudden accidents can be avoided effectively by finding early latent faults. Recently, functionalized graphene, a kind of gas sensing material, has been reported to show good application prospects in the gas sensor field. Therefore, calculations were performed to analyze the gas sensing properties of intrinsic graphene (Int-graphene) and functionalized graphene-based material, Ag-decorated graphene (Ag-graphene), for decomposition products of SF6, including SO2F2, SOF2, and SO2, based on density functional theory (DFT). We thoroughly investigated a series of parameters presenting gas-sensing properties of adsorbing process about gas molecule (SO2F2, SOF2, SO2) and double gas molecules (2SO2F2, 2SOF2, 2SO2) on Ag-graphene, including adsorption energy, net charge transfer, electronic state density, and the highest and lowest unoccupied molecular orbital. The results showed that the Ag atom significantly enhances the electrochemical reactivity of graphene, reflected in the change of conductivity during the adsorption process. SO2F2 and SO2 gas molecules on Ag-graphene presented chemisorption, and the adsorption strength was SO2F2 > SO2, while SOF2 absorption on Ag-graphene was physical adsorption. Thus, we concluded that Ag-graphene showed good selectivity and high sensitivity to SO2F2. The results can provide a helpful guide in exploring Ag-graphene material in experiments for monitoring the insulation status of SF6-insulated equipment based on detecting decomposition products of SF6. PMID:27809269

  13. Gas-phase thermal dissociation of uranium hexafluoride: Investigation by the technique of laser-powered homogeneous pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Bostick, W.D.; McCulla, W.H.; Trowbridge, L.D.

    1987-04-01

    In the gas-phase, uranium hexafluoride decomposes thermally in a quasi-unimolecular reaction to yield uranium pentafluoride and atomic fluorine. We have investigated this reaction using the relatively new technique of laser-powered homogeneous pyrolysis, in which a megawatt infrared laser is used to generate short pulses of high gas temperatures under strictly homogeneous conditions. In our investigation, SiF/sub 4/ is used as the sensitizer to absorb energy from a pulsed CO/sub 2/ laser and to transfer this energy by collisions with the reactant gas. Ethyl chloride is used as an external standard ''thermometer'' gas to permit estimation of the unimolecular reaction rate constants by a relative rate approach. When UF/sub 6/ is the reactant, CF/sub 3/Cl is used as reagent to trap atomic fluorine reaction product, forming CF/sub 4/ as a stable indicator which is easily detected by infrared spectroscopy. Using these techniques, we estimate the UF/sub 6/ unimolecular reaction rate constant near the high-pressure limit. In the Appendix, we describe a computer program, written for the IBM PC, which predicts unimolecular rate constants based on the Rice-Ramsperger-Kassel theory. Parameterization of the theoretical model is discussed, and recommendations are made for ''appropriate'' input parameters for use in predicting the gas-phase unimolecular reaction rate for UF/sub 6/ as a function of temperature and gas composition and total pressure. 85 refs., 17 figs., 14 tabs.

  14. Gas Sensing Analysis of Ag-Decorated Graphene for Sulfur Hexafluoride Decomposition Products Based on the Density Functional Theory

    Directory of Open Access Journals (Sweden)

    Xiaoxing Zhang

    2016-11-01

    Full Text Available Detection of decomposition products of sulfur hexafluoride (SF6 is one of the best ways to diagnose early latent insulation faults in gas-insulated equipment, and the occurrence of sudden accidents can be avoided effectively by finding early latent faults. Recently, functionalized graphene, a kind of gas sensing material, has been reported to show good application prospects in the gas sensor field. Therefore, calculations were performed to analyze the gas sensing properties of intrinsic graphene (Int-graphene and functionalized graphene-based material, Ag-decorated graphene (Ag-graphene, for decomposition products of SF6, including SO2F2, SOF2, and SO2, based on density functional theory (DFT. We thoroughly investigated a series of parameters presenting gas-sensing properties of adsorbing process about gas molecule (SO2F2, SOF2, SO2 and double gas molecules (2SO2F2, 2SOF2, 2SO2 on Ag-graphene, including adsorption energy, net charge transfer, electronic state density, and the highest and lowest unoccupied molecular orbital. The results showed that the Ag atom significantly enhances the electrochemical reactivity of graphene, reflected in the change of conductivity during the adsorption process. SO2F2 and SO2 gas molecules on Ag-graphene presented chemisorption, and the adsorption strength was SO2F2 > SO2, while SOF2 absorption on Ag-graphene was physical adsorption. Thus, we concluded that Ag-graphene showed good selectivity and high sensitivity to SO2F2. The results can provide a helpful guide in exploring Ag-graphene material in experiments for monitoring the insulation status of SF6-insulated equipment based on detecting decomposition products of SF6.

  15. Gas Sensing Analysis of Ag-Decorated Graphene for Sulfur Hexafluoride Decomposition Products Based on the Density Functional Theory.

    Science.gov (United States)

    Zhang, Xiaoxing; Huang, Rong; Gui, Yingang; Zeng, Hong

    2016-11-01

    Detection of decomposition products of sulfur hexafluoride (SF₆) is one of the best ways to diagnose early latent insulation faults in gas-insulated equipment, and the occurrence of sudden accidents can be avoided effectively by finding early latent faults. Recently, functionalized graphene, a kind of gas sensing material, has been reported to show good application prospects in the gas sensor field. Therefore, calculations were performed to analyze the gas sensing properties of intrinsic graphene (Int-graphene) and functionalized graphene-based material, Ag-decorated graphene (Ag-graphene), for decomposition products of SF₆, including SO₂F₂, SOF₂, and SO₂, based on density functional theory (DFT). We thoroughly investigated a series of parameters presenting gas-sensing properties of adsorbing process about gas molecule (SO₂F₂, SOF₂, SO₂) and double gas molecules (2SO₂F₂, 2SOF₂, 2SO₂) on Ag-graphene, including adsorption energy, net charge transfer, electronic state density, and the highest and lowest unoccupied molecular orbital. The results showed that the Ag atom significantly enhances the electrochemical reactivity of graphene, reflected in the change of conductivity during the adsorption process. SO₂F₂ and SO₂ gas molecules on Ag-graphene presented chemisorption, and the adsorption strength was SO₂F₂ > SO₂, while SOF₂ absorption on Ag-graphene was physical adsorption. Thus, we concluded that Ag-graphene showed good selectivity and high sensitivity to SO₂F₂. The results can provide a helpful guide in exploring Ag-graphene material in experiments for monitoring the insulation status of SF₆-insulated equipment based on detecting decomposition products of SF₆.

  16. Electrooxidation of saccharides at platinum electrode

    Science.gov (United States)

    Han, Ji-Hyung; Chung, Taek Dong

    2012-10-01

    Saccharides have been emerging as promising fuels for future energy industry because they possess high energy density and tremendous amount of them can be obtained from abundant biomass. Direct electrochemical oxidation of saccharides to generate electricity is a potentially competitive approach in terms of the demand for small, handy, and cost-effective electric power sources. To develop efficient sugar fuel cell, it is necessary to understand mechanism of electrooxidation of saccharide at electrode surface. Although glucose oxidation at platinum surface has been well known, fundamental mechanism study on electrooxidation of other sugars is still in its infancy. Based on research of glucose oxidation, we will predict the electrooxidation of other saccharides such as fructose.

  17. Thermodynamic ground states of platinum metal nitrides

    Energy Technology Data Exchange (ETDEWEB)

    Aberg, D; Sadigh, B; Crowhurst, J; Goncharov, A

    2007-10-09

    We have systematically studied the thermodynamic stabilities of various phases of the nitrides of the platinum metal elements using density functional theory. We show that for the nitrides of Rh, Pd, Ir and Pt two new crystal structures, in which the metal ions occupy simple tetragonal lattice sites, have lower formation enthalpies at ambient conditions than any previously proposed structures. The region of stability can extend up to 17 GPa for PtN{sub 2}. Furthermore, we show that according to calculations using the local density approximation, these new compounds are also thermodynamically stable at ambient pressure and thus may be the ground state phases for these materials. We further discuss the fact that the local density and generalized gradient approximations predict different values of the absolute formation enthalpies as well different relative stabilities between simple tetragonal and the pyrite or marcasite structures.

  18. Fabrication of iron-platinum ferromagnetic nanoparticles

    Science.gov (United States)

    Elkins, Kevin Eugene

    Fabrication of chemically disordered FePt particles ranging from 2--9 nm with a precision of 1 nm has been achieved through modification of key process variables including surfactant concentration, heating rates and the type of iron precursor. In addition, the shape evolution of the FePt nanoparticles during particle growth can be manipulated to give cubic or rod geometries through changes to the surfactant injection sequence and solvent system. The primary method for synthesis of the disordered FePt nanoparticles is the polyol reduction reported by Fievet et al., which has been modified and used extensively for synthesis of differing nanoparticle systems. Our procedures use platinum acetylacetonate, iron pentacarbonyl or ferric acetylacetonate as precursors for the FePt alloy, oleic acid and oleyl amine for the surfactants, 1,2-hexadecanediol to assist with the reduction of the precursors and either dioctyl ether or phenyl ether for the solvent system. For iron pentacarbonyl based reactions, adjustment of heating rates to reflux temperatures from 1--15°C per minute allows control of FePt particle diameters from 3--8 nm. Substitution of iron pentacarbonyl with ferric acetylacetonate as the iron source results in 2 nm particles. A high platinum to surfactant ratio of 10 to 1 will yield 9 nm FePt particles when iron pentacarbonyl is used as the precursor. For use of these particles in advanced applications, the synthesized particles must be transformed to the L1o phase through annealing at temperatures above 500°C. Inhibition of particle sintering can be avoided through dispersion in a NaCl matrix at a weight ratio of 400 to 1 salt to fcc FePt particles. Production of L1o FePt nanoparticles with high magnetic anisotropy with this process has been successful, allowing the original size and size distribution of the particles.

  19. Platinum-Catalyzed Selective Tin-Carbon Bond Formation

    NARCIS (Netherlands)

    Thoonen, Sander Hendrikus Lambertus

    2003-01-01

    In conclusion, two improved methods for the selective synthesis of monoorganotin trihalides were developed. The platinum-catalyzed Kocheshkov redistribution reaction of dialkyltin dichlorides with tin tetrachloride is the most interesting. Contrary to the other two methods described (the direct

  20. Wireless gas sensing in South African underground platinum mines

    CSIR Research Space (South Africa)

    Abu-Mahfouz, Adnan M

    2014-04-01

    Full Text Available Approximately 70% of South African mines are classified as fiery, where methane gas potentially could cause explosions. The number of flammable gas reports and accidents are increasing steadily for both gold and platinum mines. However...

  1. Safety profile of Colgate Platinum Professional Toothwhitening System.

    Science.gov (United States)

    Adam-Rodwell, G; Kong, B M; Bagley, D M; Tonucci, D; Christina, L M

    1994-01-01

    Colgate Platinum, a professional tooth-whitening paste containing 10% urea peroxide as the active ingredient, was evaluated for potential acute oral toxicity, genotoxicity, and irritation to oral mucosa. Oral administration to rats of a single dose of 5 g/kg of Colgate Platinum did not induce any adverse effects. Colgate Platinum was not mutagenic in Ames/Salmonella Plate Incorporation assay and did not induce primary DNA damage in the bone marrow hematopoietic cells of rats that were given oral doses of up to 1 g/kg for 5 consecutive days. Results of the oral mucosa irritation study in rats indicated that Colgate Platinum did not induce damage to soft and hard tissues of oral cavity after repeated applications for 28 days. Collectively, the data from these studies document the safety of the product for the intended use.

  2. Resolving the Structure of Active Sites on Platinum Catalytic Nanoparticles

    DEFF Research Database (Denmark)

    Chang, Lan Yun; Barnard, Amanda S.; Gontard, Lionel Cervera

    2010-01-01

    Accurate understanding of the structure of active sites is fundamentally important in predicting catalytic properties of heterogeneous nanocatalysts. We present an accurate determination of both experimental and theoretical atomic structures of surface monatomic steps on industrial platinum nanop...

  3. Defining Therapy for Recurrent Platinum-sensitive Ovarian Cancer

    Science.gov (United States)

    In this phase III clinical trial, women with platinum-sensitive, recurrent ovarian epithelial, fallopian tube, or primary peritoneal cancer will be randomly assigned to undergo secondary cytoreductive surgery, if they are candidates for such surgery, and

  4. Platinum single crystal electrodes for the electrocatalysis of methane oxidation

    Directory of Open Access Journals (Sweden)

    Mayara Munaretto

    2011-03-01

    Full Text Available The main objective of this paper is to characterize the voltammetric profiles of platinum single crystals of low Miller indexes Pt(100 and Pt(110 and study their catalytic activities on the oxidation of methane. In this way, it was developed a metallic surface modified by presence of other metal oxide, which presents catalytic activity for this reaction. It is well known that the electrooxidation of methane (CH4 leads mainly to the formation of CO2 and H2O, however, the oxidation can also lead to the formation of CO, a reaction intermediate that has strong interaction with metal surfaces, such as platinum. This molecule tends to accumulate on the platinum surface and to passive it, due to the self-poisoning, decreasing its catalytic activity. Therefore, the main aim of this work was the development of a platinum electrode modified by deposition of titanium oxide, which presented electrocatalytic properties for the oxidation of methane.

  5. Platinum blue staining of cells grown in electrospun scaffolds.

    Science.gov (United States)

    Yusuf, Mohammed; Millas, Ana Luiza G; Estandarte, Ana Katrina C; Bhella, Gurdeep K; McKean, Robert; Bittencourt, Edison; Robinson, Ian K

    2014-01-01

    Fibroblast cells grown in electrospun polymer scaffolds were stained with platinum blue, a heavy metal stain, and imaged using scanning electron microscopy. Good contrast on the cells was achieved compared with samples that were gold sputter coated. The cell morphology could be clearly observed, and the cells could be distinguished from the scaffold fibers. Here we optimized the required concentration of platinum blue for imaging cells grown in scaffolds and show that a higher concentration causes platinum aggregation. Overall, platinum blue is a useful stain for imaging cells because of its enhanced contrast using scanning electron microscopy (SEM). In the future it would be useful to investigate cell growth and morphology using three-dimensional imaging methods.

  6. Internalization of Ineffective Platinum Complex in Nanocapsules Renders It Cytotoxic.

    Science.gov (United States)

    Vrana, Oldrich; Novohradsky, Vojtech; Medrikova, Zdenka; Burdikova, Jana; Stuchlikova, Olga; Kasparkova, Jana; Brabec, Viktor

    2016-02-18

    Anticancer therapy by platinum complexes, based on nanocarrier-based delivery, may offer a new approach to improve the efficacy and tolerability of the platinum family of anticancer drugs. The original rules for the design of new anticancer platinum drugs were affected by the fact that, although cisplatin (cis-[PtCl2 (NH3)2) was an anticancer drug, its isomer transplatin was not cytotoxic. For the first time, it is demonstrated that simple encapsulation of an inactive platinum compound in phospholipid bilayers transforms it into an efficient cytotoxic agent. Notably, the encapsulation of transplatin makes it possible to overcome the resistance mechanisms operating in cancer cells treated with cisplatin and prevents inactivation of transplatin in the extracellular environment. It is also shown that transplatin delivered to the cells in nanocapsules, in contrast to free (nonencapsulated) complex, forms cytotoxic cross-links on DNA.

  7. Platinum electrodeposition from a dinitrosulfatoplatinate(II) electrolyte

    Science.gov (United States)

    Weiser, Mathias; Schulze, Claudia; Schneider, Michael; Michaelis, Alexander

    2016-12-01

    In this work a halogen-free electrolyte to deposit platinum nanoparticle is studied. The investigated [Pt(NO2)2SO4]2--complex is suitable for electrochemical deposition on halogen sensitive substrates. The mechanism and kinetic of particle deposition is investigated using a glassy carbon rotating disk electrode. Nano sized platinum particles are deposited by using pulse plating technique. The size of the smallest platinum nanoparticle is 5 nm. The shape of the particle distribution strictly depends on the plating time. The platinum deposition is usually superimposed with hydrogen evolution. A diffusion coefficient of the [Pt(NO2)2SO4]2--complex is determined to 5.4 × 10-6 cm2s-1. The current efficiency depends on the deposition parameters and amounts to 37% under the chosen pulse plating conditions.

  8. Interfacial electronic effects control the reaction selectivity of platinum catalysts

    Science.gov (United States)

    Chen, Guangxu; Xu, Chaofa; Huang, Xiaoqing; Ye, Jinyu; Gu, Lin; Li, Gang; Tang, Zichao; Wu, Binghui; Yang, Huayan; Zhao, Zipeng; Zhou, Zhiyou; Fu, Gang; Zheng, Nanfeng

    2016-05-01

    Tuning the electronic structure of heterogeneous metal catalysts has emerged as an effective strategy to optimize their catalytic activities. By preparing ethylenediamine-coated ultrathin platinum nanowires as a model catalyst, here we demonstrate an interfacial electronic effect induced by simple organic modifications to control the selectivity of metal nanocatalysts during catalytic hydrogenation. This we apply to produce thermodynamically unfavourable but industrially important compounds, with ultrathin platinum nanowires exhibiting an unexpectedly high selectivity for the production of N-hydroxylanilines, through the partial hydrogenation of nitroaromatics. Mechanistic studies reveal that the electron donation from ethylenediamine makes the surface of platinum nanowires highly electron rich. During catalysis, such an interfacial electronic effect makes the catalytic surface favour the adsorption of electron-deficient reactants over electron-rich substrates (that is, N-hydroxylanilines), thus preventing full hydrogenation. More importantly, this interfacial electronic effect, achieved through simple organic modifications, may now be used for the optimization of commercial platinum catalysts.

  9. Linear models for sound from supersonic reacting mixing layers

    Science.gov (United States)

    Chary, P. Shivakanth; Samanta, Arnab

    2016-12-01

    We perform a linearized reduced-order modeling of the aeroacoustic sound sources in supersonic reacting mixing layers to explore their sensitivities to some of the flow parameters in radiating sound. Specifically, we investigate the role of outer modes as the effective flow compressibility is raised, when some of these are expected to dominate over the traditional Kelvin-Helmholtz (K-H) -type central mode. Although the outer modes are known to be of lesser importance in the near-field mixing, how these radiate to the far-field is uncertain, on which we focus. On keeping the flow compressibility fixed, the outer modes are realized via biasing the respective mean densities of the fast (oxidizer) or slow (fuel) side. Here the mean flows are laminar solutions of two-dimensional compressible boundary layers with an imposed composite (turbulent) spreading rate, which we show to significantly alter the growth of instability waves by saturating them earlier, similar to in nonlinear calculations, achieved here via solving the linear parabolized stability equations. As the flow parameters are varied, instability of the slow modes is shown to be more sensitive to heat release, potentially exceeding equivalent central modes, as these modes yield relatively compact sound sources with lesser spreading of the mixing layer, when compared to the corresponding fast modes. In contrast, the radiated sound seems to be relatively unaffected when the mixture equivalence ratio is varied, except for a lean mixture which is shown to yield a pronounced effect on the slow mode radiation by reducing its modal growth.

  10. Platinum group metal nitrides and carbides: synthesis, properties and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Ivanovskii, Alexander L [Institute of Solid State Chemistry, Urals Branch of the Russian Academy of Sciences, Ekaterinburg (Russian Federation)

    2009-04-30

    Experimental and theoretical data on new compounds, nitrides and carbides of the platinum group 4d and 5d metals (ruthenium, rhodium, palladium, osmium, iridium, platinum), published over the past five years are summarized. The extreme mechanical properties of platinoid nitrides and carbides, i.e., their high strength and low compressibility, are noted. The prospects of further studies and the scope of application of these compounds are discussed.

  11. Problems and Characteristics of Russian Platinum Metals Exporters

    Institute of Scientific and Technical Information of China (English)

    ANDREEV A. M.; KELCHEVSKAYA N. R.

    2012-01-01

    The paper revealed the place and role of Russia in the global market of platinum metals,highlighted features of pricing in the export of Russian platinum group metals,the main problems of pricing in the export contracts related to the instability of markets and imperfect currency and customs legislation of the Russian Federation,proposed innovative ways to solutions to existing problems in the preparation and conclusion of export contracts.

  12. CROWN FUNCTIONALIZED LINEAR POLYSILOXANE PLATINUM COMPLEX AS HYDROSILYLATION CATALYST

    Institute of Scientific and Technical Information of China (English)

    CHEN Yuanyin; LU Xueran; GONG Shuling; ZHANG Baolian

    1994-01-01

    A modified method of preparing crown functionalized linear polysiloxane has been described.4'-allylbenzo-15-crown-5 was subjected to hydrosilylation with methyldichlorosilane,followed by polycondensation with silanol-terminated polydimethylsiloxane to give the title crown functionalized linear polysiloxane. It was found that the polysiloxane could be coordinated with platinum salt to form platinum complex, which could catalyze the hydrosilylation of olefins with triethoxysilane efficiently.

  13. Mineral resource of the month: platinum group metals

    Science.gov (United States)

    Loferski, Patricia J.

    2010-01-01

    The article focuses on platinum group metals (PGMs) and their properties. According to the author, PGMs, which include iridium, osmium, palladium, platinum, rhodium, and ruthenium, are among the rarest mineral commodities in the Earth's crust. PGMs are primarily used as catalytic converters that clean harmful exhaust from vehicle engines. They are also used in the chemical industry as catalysts in the production of nitric acid and in the petroleum refining industry.

  14. Synthesis of nanosized platinum based catalyst using sol-gel process

    Science.gov (United States)

    Ingale, S. V.; Wagh, P. B.; Bandyopadhyay, D.; Singh, I. K.; Tewari, R.; Gupta, S. C.

    2015-02-01

    The nano-sized platinum based catalysts using high surface area silica support have been prepared by sol-gel method. Tetramethoxysilane (TMOS) diluted in methanol was hydrolyzed to form a porous silica gel. Platinum (2%) was loaded at sol state using platinum chloride solution. After gelation, the solvent from the gel pores was extracted at ambient temperature which resulted in porous silica matrix incorporated with nanosized platinum. X-ray diffraction studies indicated the presence of elemental platinum in the silica-platinum composites. Transmission electron microscopy of the platinum -silica composites revealed that nanosized platinum particles of about 5-10 nm are homogeneously dispersed in silica matrix. Chemisorptions studies showed high dispersion (more than 50%) of platinum on silica support with specific surface area of 400 m2/g which puts them as promising candidates as catalyst in heterogeneous reactions.

  15. Platinum drugs and DNA repair mechanisms in lung cancer.

    Science.gov (United States)

    Bonanno, Laura; Favaretto, Adolfo; Rosell, Rafael

    2014-01-01

    The standard first-line treatment for around 80% of newly-diagnosed advanced non-small cell lung cancer (NSCLC) is chemotherapy. Currently, patients are allocated to chemotherapy on the basis of clinical conditions, comorbidities and histology. If feasible, platinum-based chemotherapy is considered as the most efficacious option. Due to the heterogeneity in terms of platinum-sensitivity among patients with NSCLC, great efforts have been made in order to identify molecular predictive markers of platinum resistance. Based on the mechanism of action of platinum, several components of DNA repair pathways have been investigated as potential predictive markers. The main DNA repair pathways involved in the repair of platinum-induced DNA damage are nucleotide excision repair and homologous recombination. The most studied potential predictive markers of platinum-sensitivity are Excision Repair Cross Complementing-1 (ERCC1) and Brest Cancer Type-I Susceptibility protein (BRCA1); however, increasing biological knowledge about DNA repair pathways suggests the potential clinical usefulness of integrated analysis of multiple DNA repair components.

  16. Liposomes, a promising strategy for clinical application of platinum derivatives.

    Science.gov (United States)

    Zalba, Sara; Garrido, María J

    2013-06-01

    Liposomes represent a versatile system for drug delivery in various pathologies. Platinum derivatives have been demonstrated to have therapeutic efficacy against several solid tumors. But their use is limited due to their side effects. Since liposomal formulations are known to reduce the toxicity of some conventional chemotherapeutic drugs, the encapsulation of platinum derivatives in these systems may be useful in reducing toxicity and maintaining an adequate therapeutic response. This review describes the strategies applied to platinum derivatives in order to improve their therapeutic activity, while reducing the incidence of side effects. It also reviews the results found in the literature for the different platinum-drugs liposomal formulations and their current status. The design of liposomes to achieve effectiveness in antitumor treatment is a goal for platinum derivatives. Liposomes can change the pharmacokinetic parameters of these encapsulated drugs, reducing their side effects. However, few liposomal formulations have demonstrated a significant advantage in therapeutic terms. Lipoplatin, a cisplatin formulation in Phase III, combines a reduction in the toxicity associated with an antitumor activity similar to the free drug. Thermosensitive or targeted liposomes for tumor therapy are also included in this review. Few articles about this strategy applied to platinum drugs can be found in the literature.

  17. In vitro permeation of platinum and rhodium through Caucasian skin.

    Science.gov (United States)

    Franken, A; Eloff, F C; Du Plessis, J; Badenhorst, C J; Jordaan, A; Du Plessis, J L

    2014-12-01

    During platinum group metals (PGMs) refining the possibility exists for dermal exposure to PGM salts. The dermal route has been questioned as an alternative route of exposure that could contribute to employee sensitisation, even though literature has been focused on respiratory exposure. This study aimed to investigate the in vitro permeation of platinum and rhodium through intact Caucasian skin. A donor solution of 0.3mg/ml of metal, K2PtCl4 and RhCl3 respectively, was applied to the vertical Franz diffusion cells with full thickness abdominal skin. The receptor solution was removed at various intervals during the 24h experiment, and analysed with high resolution ICP-MS. Skin was digested and analysed by ICP-OES. Results indicated cumulative permeation with prolonged exposure, with a significantly higher mass of platinum permeating after 24h when compared to rhodium. The mass of platinum retained inside the skin and the flux of platinum across the skin was significantly higher than that of rhodium. Permeated and skin retained platinum and rhodium may therefore contribute to sensitisation and indicates a health risk associated with dermal exposure in the workplace.

  18. Numerical simulation of high speed chemically reacting flows

    Science.gov (United States)

    Schuricht, Scott Richard

    . The scramjet case demonstrates the usefulness of the method as a predictive tool for reacting flows. The rocket motor nozzle case demonstrates the capability of the method to handle mixed subsonic/transonic/supersonic flow environments. Five different chemical reaction mechanisms were studied illustrating the flexibility of the method.

  19. Emission of mercury monobromide exciplex in gas-discharge plasma based on mixture of mercury dibromide vapor with sulfur hexafluoride and helium

    Science.gov (United States)

    Malinina, A. A.; Shuaibov, A. K.

    2011-02-01

    We present the results of investigations of an emission of a mercury monobromide exciplex in gas-discharge plasma of an atmospheric pressure barrier discharge based on a mixture of mercury dibromide vapor, sulfur hexafluoride, and helium. We optimized the emission power of mercury monobromide exciplexes with respect to the partial pressures of the working mixture. An average emission power of 0.42 W (λmax = 502 nm) is achieved in a cylindrical emission source with a small working volume (0.8 cm3) at a pumping pulse repetition rate of 6 kHz. We determined electron energy distribution functions, transport characteristics, specific discharge power losses for electron processes, electron concentration and temperature, as well as rate constants of elastic and inelastic scattering of electrons by components of the working mixture in relation to the ratio of the field strength to the total concentration of components of the working mixture. We discuss processes that increase the population of the mercury monobromide exciplex. Gas-discharge plasma created in a mixture of mercury dibromide vapor with sulfur hexafluoride and helium can be used as a working medium of an emission source in the blue-green spectral range for the use in scientific research in biotechnology, photonics, and medicine, as well as for creating indicator gas-discharge panels.

  20. Platinum- and platinum alloy-coated palladium and palladium alloy particles and uses thereof

    Science.gov (United States)

    Adzic, Radoslav; Zhang, Junliang; Mo, Yibo; Vukmirovic, Miomir Branko

    2010-04-06

    The present invention relates to particle and nanoparticle composites useful as oxygen-reduction electrocatalysts. The particle composites are composed of a palladium or palladium-alloy particle or nanoparticle substrate coated with an atomic submonolayer, monolayer, bilayer, or trilayer of zerovalent platinum atoms. The invention also relates to a catalyst and a fuel cell containing the particle or nanoparticle composites of the invention. The invention additionally includes methods for oxygen reduction and production of electrical energy by using the particle and nanoparticle composites of the invention.

  1. Clinical pharmacology and pharmacokinetics of cis-platinum and analogs.

    Science.gov (United States)

    Ribaud, P; Gouveia, J; Bonnay, M; Mathe, G

    1981-01-01

    cis-Platinum (DDP), the first metal coordination complex introduced into clinical trials, is remarkable for its therapeutic index. A short review of the numerator of this index, ie, the clinical activities of DDP given as a single agent or in combination therapy is presented. Toxicity of DDP, the denominator of the index, is given more attention, particularly nephrotoxicity, whose cumulative character and molecular mechanism are still in question and which can most often be prevented by following certain safety rules that are detailed in this paper. Pharmacokinetics data of free and filterable platinum are reviewed and discussed according to the different modalities of administration of DDP, and to what is known about its toxicity and its mechanism of cell kill. The rationale for using DDP in combination treatment is presented and the question of possible long-term toxicities is raised. cis-platinum analogs are sought for the purpose of enlarging the spectrum of activity, increasing selectivity and diminishing toxicity. Malonato-platinum has been shown not to be cross-resistant with DDP and to be clinically effective in adult acute leukemia. In a phase I study, malonato-platinum, which is poorly soluble, was administered in 6-24-hour infusions to 49 patients in doses ranging from 3 to 32 mg/kg. GI toxicity was universal. Hematological toxicity appeared to be mild and not clearly dose-related (the 3-32 mg/kg patients were not yet evaluable). Platinum pharmacokinetics in urine and plasma were performed using flameless absorption spectrophotometry. Preliminary results have suggested that malonato-platinum presented several pharmacokinetic features in common with DDP. Minor responses were seen in four solid tumor patients, three of whom were refractory to DDP. Other analogs soon to be introduced into clinical trials are listed.

  2. Platinum metals in magmatic sulfide ores

    Science.gov (United States)

    Naldrett, A.J.; Duke, J.M.

    1980-01-01

    Platinum-group elements (PGE) are mined predominantly from deposits that have formed by the segregation of molten iron-nickel-copper sulfides from silicate magmas. The absolute concentrations of PGE in sulfides from different deposits vary over a range of five orders of magnitude, whereas those of other chalcophile elements vary by factors of only 2 to 100. However, the relative proportions of the different PGE in a given deposit are systematically related to the nature of the parent magma. The absolute and relative concentrations of PGE in magmatic sulfides are explained in terms of the degree of partial melting of mantle peridotite required to produce the parent magma and the processes of batch equilibration and fractional segregation of sulfides. The Republic of South Africa and the U.S.S.R. together possess more than 97 percent of the world PGE reserves, but significant undeveloped resources occur in North America. The Stillwater complex in Montana is perhaps the most important example. Copyright ?? 1980 AAAS.

  3. Platinum states in citrate sols by EXAFS.

    Science.gov (United States)

    Lin, Chia-Shiang; Khan, Maksudur R; Lin, Shawn D

    2005-07-01

    Platinum sols have been prepared by citrate reduction in the temperature range of 343-363 K. The Pt state in the solution was examined by EXAFS (extended X-ray absorption fine-structure spectroscopy). It did not show any PtPt bonding, a characteristic for reduced Pt sols. EXAFS model fitting further proved the presence of PtO with 4 oxygen neighbors, which suggests a tetraplanar coordination configuration. The possibility of neighboring Pt sharing oxygen ligand or the formation of PtO(x) is rejected by EXAFS model fitting. Citrate was found to be the most likely ligand to orient its oxygen end toward a charged Pt center. Thus we have revealed that the citrate treatment at this temperature range was clearly insufficient to reduce H2PtCl(6(aq)). Neither an extended period of reaction time nor an excess citrate reduced the Pt precursor. It is therefore highly recommended that the citrate sols should be carefully prepared and used.

  4. Development of radioactive platinum group metal catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H.S.; Kim, Y.S.; Kim, Y.E. [and others

    1999-03-01

    The fission product nuclides generated during the irradiation of reactor fuel include many useful elements, among them platinum group metals such as ruthenium, rhodium and palladium which are of great industrial importance, occur rarely in nature and are highly valuable. In this research, the authors reviewed various PGM recovery methods. Recovery of palladium from seven-component simulated waste solutions was conducted by selective precipitation method. The recovery yield was more than 99.5% and the purity of the product was more than 99%. Wet-proof catalyst was prepared with the recovered palladium. The specific surface area of the catalyst support was more than 400m{sup 2}/g.The content of palladium impregnated on the support was 1 to 10 wt. %. Hydrogen isotope exchange efficiency of more than 93% to equilibrium with small amount of the catalyst was obtained. It was turned out possible to consider using such palladium or other very low active PGM materials in applications where its activity is unimportant as in nuclear industries. (author). 86 refs., 44 tabs., 88 figs.

  5. Development of radioactive platinum group metal catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H.S.; Kim, Y.S.; Kim, Y.E. [and others

    1999-03-01

    The fission product nuclides generated during the irradiation of reactor fuel include many useful elements, among them platinum group metals such as ruthenium, rhodium and palladium which are of great industrial importance, occur rarely in nature and are highly valuable. In this research, the authors reviewed various PGM recovery methods. Recovery of palladium from seven-component simulated waste solutions was conducted by selective precipitation method. The recovery yield was more than 99.5% and the purity of the product was more than 99%. Wet-proof catalyst was prepared with the recovered palladium. The specific surface area of the catalyst support was more than 400m{sup 2}/g.The content of palladium impregnated on the support was 1 to 10 wt. %. Hydrogen isotope exchange efficiency of more than 93% to equilibrium with small amount of the catalyst was obtained. It was turned out possible to consider using such palladium or other very low active PGM materials in applications where its activity is unimportant as in nuclear industries. (author). 86 refs., 44 tabs., 88 figs.

  6. Standard test method for the analysis of refrigerant 114, plus other carbon-containing and fluorine-containing compounds in uranium hexafluoride via fourier-transform infrared (FTIR) spectroscopy

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 This test method covers determining the concentrations of refrigerant-114, other carbon-containing and fluorine-containing compounds, hydrocarbons, and partially or completely substituted halohydrocarbons that may be impurities in uranium hexafluoride. The two options are outlined for this test method. They are designated as Part A and Part B. 1.1.1 To provide instructions for performing Fourier-Transform Infrared (FTIR) spectroscopic analysis for the possible presence of Refrigerant-114 impurity in a gaseous sample of uranium hexafluoride, collected in a "2S" container or equivalent at room temperature. The all gas procedure applies to the analysis of possible Refrigerant-114 impurity in uranium hexafluoride, and to the gas manifold system used for FTIR applications. The pressure and temperatures must be controlled to maintain a gaseous sample. The concentration units are in mole percent. This is Part A. 1.2 Part B involves a high pressure liquid sample of uranium hexafluoride. This method can be appli...

  7. Synthesis and characterization of potential iron–platinum drugs and supplements by laser liquid photolysis

    CSIR Research Space (South Africa)

    Nkosi, SS

    2013-06-01

    Full Text Available , and structure was systematically investigated. Different nanostructures of iron–platinum alloy and chemically disordered iron–platinum L10 phase were obtained without annealing. The prepared precursor solution underwent deep photolysis to polycrystalline iron...

  8. A dual-emissive ionic liquid based on an anionic platinum(II) complex

    OpenAIRE

    Ogawa, Tomohiro; Yoshida, Masaki; Ohara, Hiroki; Kobayashia, Atsushi; Kato, Masako

    2015-01-01

    An ionic liquid fabricated froman anionic cyclometalated platinum(II) complex and an imidazolium cation exhibits dual emission from the monomeric and aggregated forms of the platinum complex anions, leading to temperature-dependent color changes of luminescence.

  9. A dual-emissive ionic liquid based on an anionic platinum(ii) complex.

    Science.gov (United States)

    Ogawa, Tomohiro; Yoshida, Masaki; Ohara, Hiroki; Kobayashi, Atsushi; Kato, Masako

    2015-09-07

    An ionic liquid fabricated from an anionic cyclometalated platinum(ii) complex and an imidazolium cation exhibits dual emission from the monomeric and aggregated forms of the platinum complex anions, leading to temperature-dependent color changes of luminescence.

  10. ReACT!: An Interactive Educational Tool for AI Planning for Robotics

    Science.gov (United States)

    Dogmus, Zeynep; Erdem, Esra; Patogulu, Volkan

    2015-01-01

    This paper presents ReAct!, an interactive educational tool for artificial intelligence (AI) planning for robotics. ReAct! enables students to describe robots' actions and change in dynamic domains without first having to know about the syntactic and semantic details of the underlying formalism, and to solve planning problems using…

  11. RECENT ADVANCES IN STUDIES ON MULTIPHASE AND REACTING FLOWS IN CHINA

    Institute of Scientific and Technical Information of China (English)

    周力行

    2002-01-01

    The recent developments and advances of studies on multiphase and reacting flows, including gas-solid, gas-liquid, liquid-solid and reacting flows, in China are reviewed. Special emphasis is laid on the fundamental studies and numerical models. Some important experimental results are also reported. But measurement techniques are not covered.

  12. Pharmacokinetics of Malonato (1,2 diaminocyclohexane) platinum.

    Science.gov (United States)

    Kelsen, D P; Ribaud, P; Alcock, N; Burchenal, J H; Young, C W; Mathe, G

    1981-01-01

    Malonato-(1,2 diaminocyclohexane) platinum (MP) is a new platinum analog currently undergoing phase I clinical trials. Using flameless atomic absorption spectrophotometry, the pharmacokinetics of MP were studied at five dosage levels. The drug was given as a prolonged intravenous infusion, lasting from 6 to 24 hours. Peak plasma platinum concentrations (Pt) were seen at the end of the infusion, and ranged from 1.1 microgram/ml when 3 mg/kg was given to 14-20.5 micrograms/ml at the 24-mg/kg level. Following completion of the infusion, a prolonged T1/2 beta (mean 63.5 hours) was noted. The percentage of free:total platinum was high (90-95%) at the beginning of the infusion but fell rapidly, to only 15-21% at the end of the 24-hour infusions. Urinary excretion accounted for 16-37.5% of the total administered dose. MP appears to have several pharmacokinetic features in common with cisplatin: rapid binding to protein, a prolonged terminal phase half-life involving primarily bound platinum, and incomplete excretion by the kidney.

  13. Neurotoxicity Caused by the Treatment with Platinum Analogues

    Directory of Open Access Journals (Sweden)

    Sousana Amptoulach

    2011-01-01

    Full Text Available Platinum agents (cisplatin, carboplatin, and oxaliplatin are a class of chemotherapy agents that have a broad spectrum of activity against several solid tumors. Toxicity to the peripheral nervous system is the major dose-limiting toxicity of at least some of the platinum drugs of clinical interest. Among the platinum compounds in clinical use, cisplatin is the most neurotoxic, inducing mainly sensory neuropathy of the upper and lower extremities. Carboplatin is generally considered to be less neurotoxic than cisplatin, but it is associated with a higher risk of neurological dysfunction if administered at high dose or in combination with agents considered to be neurotoxic. Oxaliplatin induces two types of peripheral neuropathy, acute and chronic. The incidence of oxaliplatin-induced neuropathy is related to various risk factors such as treatment schedule, cumulative dose, and time of infusion. To date, several neuroprotective agents including thiol compounds, vitamin E, various anticonvulsants, calcium-magnesium infusions, and other nonpharmacological strategies have been tested for their ability to prevent platinum-induced neurotoxicity with controversial results. Further studies on the prevention and treatment of neurotoxicity of platinum analogues are warranted.

  14. Presentation and Diagnosis of Hypersensitivity to Platinum Drugs.

    Science.gov (United States)

    Caiado, Joana; Castells, Mariana

    2015-04-01

    Hypersensitivity reactions (HSRs) to platinum drugs are increasing due to their extensive use in a wide variety of malignancies and the repeated exposures in patients with increased life expectancy. Understanding the incidence of HSR to platinum drugs and associated risk factors can help with the diagnosis and may provide protection against severe HSRs. A thorough clinical history with identification of the typical and atypical symptoms, the relationship with the platin administration, and the number of previous exposures are the key to the diagnosis. An elevated serum tryptase at the time of the HSR indicates that IgE and/or mast cells/basophils were involved in the HSR. Skin testing to platinum drugs is a highly sensitive and specific diagnostic tool, which helps provide risk stratification and management recommendations. Platinum specific IgE measurement and basophil activation test (BAT) are emerging as new diagnostic tools and in combination with skin testing can help support the diagnosis and the cross-reactivity between the three most commonly used platinum drugs, namely carboplatin, cisplatin, and oxaliplatin.

  15. Structures of 38-atom gold-platinum nanoalloy clusters

    Energy Technology Data Exchange (ETDEWEB)

    Ong, Yee Pin; Yoon, Tiem Leong [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Lim, Thong Leng [Faculty of Engineering and Technology, Multimedia University, Melaka Campus, 75450 Melaka (Malaysia)

    2015-04-24

    Bimetallic nanoclusters, such as gold-platinum nanoclusters, are nanomaterials promising wide range of applications. We perform a numerical study of 38-atom gold-platinum nanoalloy clusters, Au{sub n}Pt{sub 38−n} (0 ≤ n ≤ 38), to elucidate the geometrical structures of these clusters. The lowest-energy structures of these bimetallic nanoclusters at the semi-empirical level are obtained via a global-minimum search algorithm known as parallel tempering multi-canonical basin hopping plus genetic algorithm (PTMBHGA), in which empirical Gupta many-body potential is used to describe the inter-atomic interactions among the constituent atoms. The structures of gold-platinum nanoalloy clusters are predicted to be core-shell segregated nanoclusters. Gold atoms are observed to preferentially occupy the surface of the clusters, while platinum atoms tend to occupy the core due to the slightly smaller atomic radius of platinum as compared to gold’s. The evolution of the geometrical structure of 38-atom Au-Pt clusters displays striking similarity with that of 38-atom Au-Cu nanoalloy clusters as reported in the literature.

  16. The Researches on Performance and Technology of Strengthened Pure Platinum Wire

    Institute of Scientific and Technical Information of China (English)

    ZHAI Buying; WU Baoan; PAN Xiong; YANG Hao; WANG Yunchun; CHEN Xiaojun; WANG Jianshen; LI Guogang; XUE Liqian

    2012-01-01

    This paper discusses about the purity of strengthened pure platinum wire and the development method of platinum micro wire,in order to solve the difficulties of low tensile strength,easy to break,and low rate of micro wire.And it contrasts some performance of strengthened pure platinum wire and sponge Pt wire.The researches draw a conclusion that the thermoelectric properties of strengthened pure platinum micro wire was in accordance with national standards and satisfied users' requirements.

  17. The effects of platinum on nickel electrodes in the nickel hydrogen cell

    Science.gov (United States)

    Zimmerman, Albert H.

    1991-01-01

    Interactions of platinum and platinum compounds with the nickel electrode that are possible in the nickel hydrogen cell, where both the nickel electrode and a platinum catalyst hydrogen electrode are in intimate contact with the alkaline electrolyte, are examined. Additionally, a mechanism of nickel cobalt oxyhydroxide formation in NiH2 cells is presented.

  18. Preparation and Characterization of Atactic Poly(vinyl alcohol)/Platinum Nanocomposites by Electrospinning

    Science.gov (United States)

    Seok Lyoo, Won; Jae Lee, Young; Wook Cha, Jin; Jae Kim, Min; Woo Joo, Sang; Soon Gal, Yeong; Hwan Oh, Tae; Soo Han, Sung

    2010-06-01

    Poly(vinyl alcohol) (PVA)/platinum composite nanofibers were successfully prepared by the electrospinning method. Water-based colloidal platinum in a PVA solution was directly mixed without any chemical or structural modifications into PVA polymer fibers to form organic-inorganic composite nanofibers. The PVA/platinum composite nanofibers were characterized by field emission scanning electron microscopy (SEM).

  19. Platinum Publications, December 30, 2016–January 25, 2017 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 42 prestigious science journals. This list represents articles published during the time period shown above, as generated from PubMed. Articles designated as Platinum Highlights are noteworthy articles selected from among the most recently published Platinum Publications.

  20. POLYMER-PLATINUM COMPLEX CATALYSTS FOR OXIDATION OF METHANOL TO FORMALDEHYDE

    Institute of Scientific and Technical Information of China (English)

    HUANG Meiyu; HUANG Li; ZHENG Qingyao; WANG Dianxun; JIANG Yingyan

    1984-01-01

    Two kinds of polymer-platinum complexes: silica-supported poly-γ-diphenylphosphinopropyl-siloxane-platinum complex and silica-supported polyphenylsilazane-platinum complex, have been found very active and selective in catalyzation of oxidation of methanol to formaldehyde at room temperature and under an atmospheric oxygen pressure. Their catalytic activities are greatly affected by P or N/Pt gram atomic ratio.

  1. 75 FR 77572 - Proposed Revision of Class E Airspace; Platinum AK

    Science.gov (United States)

    2010-12-13

    ... Federal Aviation Administration 14 CFR Part 71 Proposed Revision of Class E Airspace; Platinum AK AGENCY... action proposes to revise Class E airspace at Platinum AK. The creation of a new Standard Instrument Approach Procedure (SIAP) at the Platinum Airport has made this action necessary to enhance safety...

  2. 76 FR 67793 - Notification of Expanded Pricing Grid for Precious Metals Products Containing Platinum and Gold...

    Science.gov (United States)

    2011-11-02

    ... United States Mint Notification of Expanded Pricing Grid for Precious Metals Products Containing Platinum..., 2009, outlining the new pricing methodology for numismatic products containing platinum and gold. Since that time, the price of platinum and gold has increased considerably, and is approaching the...

  3. 40 CFR 440.110 - Applicability; description of the platinum ore subcategory.

    Science.gov (United States)

    2010-07-01

    ... platinum ore subcategory. 440.110 Section 440.110 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Platinum Ores Subcategory § 440.110 Applicability; description of the platinum ore subcategory. The provisions of...

  4. Flow Injection Analysis with Electrochemical Detection for Rapid Identification of Platinum-Based Cytostatics and Platinum Chlorides in Water

    Directory of Open Access Journals (Sweden)

    Marketa Kominkova

    2014-02-01

    Full Text Available Platinum-based cytostatics, such as cisplatin, carboplatin or oxaliplatin are widely used agents in the treatment of various types of tumors. Large amounts of these drugs are excreted through the urine of patients into wastewaters in unmetabolised forms. This phenomenon leads to increased amounts of platinum ions in the water environment. The impacts of these pollutants on the water ecosystem are not sufficiently investigated as well as their content in water sources. In order to facilitate the detection of various types of platinum, we have developed a new, rapid, screening flow injection analysis method with electrochemical detection (FIA-ED. Our method, based on monitoring of the changes in electrochemical behavior of analytes, maintained by various pH buffers (Britton-Robinson and phosphate buffer and potential changes (1,000, 1,100 and 1,200 mV offers rapid and cheap selective determination of platinum-based cytostatics and platinum chlorides, which can also be present as contaminants in water environments.

  5. Flow injection analysis with electrochemical detection for rapid identification of platinum-based cytostatics and platinum chlorides in water.

    Science.gov (United States)

    Kominkova, Marketa; Heger, Zbynek; Zitka, Ondrej; Kynicky, Jindrich; Pohanka, Miroslav; Beklova, Miroslava; Adam, Vojtech; Kizek, Rene

    2014-02-04

    Platinum-based cytostatics, such as cisplatin, carboplatin or oxaliplatin are widely used agents in the treatment of various types of tumors. Large amounts of these drugs are excreted through the urine of patients into wastewaters in unmetabolised forms. This phenomenon leads to increased amounts of platinum ions in the water environment. The impacts of these pollutants on the water ecosystem are not sufficiently investigated as well as their content in water sources. In order to facilitate the detection of various types of platinum, we have developed a new, rapid, screening flow injection analysis method with electrochemical detection (FIA-ED). Our method, based on monitoring of the changes in electrochemical behavior of analytes, maintained by various pH buffers (Britton-Robinson and phosphate buffer) and potential changes (1,000, 1,100 and 1,200 mV) offers rapid and cheap selective determination of platinum-based cytostatics and platinum chlorides, which can also be present as contaminants in water environments.

  6. Hydrogenation of o-cresol on platinum catalyst: Catalytic experiments and first-principles calculations

    Science.gov (United States)

    Li, Yaping; Liu, Zhimin; Xue, Wenhua; Crossley, Steven P.; Jentoft, Friederike C.; Wang, Sanwu

    2017-01-01

    Catalytic experiments were performed for the hydrogenation of o-cresol in n-dodecane over a platinum catalyst. Batch reactions analyzed with an in-situ ATR IR probe suggest that the hydrogenation results in the formation of the final product, 2-methyl-cyclohexanol, with 2-methyl-cyclohexanone as the intermediate product. Ab initio density-functional theory was employed to investigate the atomic-scale mechanism of o-cresol hydrogenation on the Pt(111) surface. The formation of 2-methyl-cyclohexanone was found to involve two steps. The first step is a hydrogen abstraction, that is, the H atom in the hydroxyl group migrates to the Pt surface. The second step is hydrogenation, that is, the pre-existing H atoms on Pt react with the carbon atoms in the aromatic ring. On the other hand, 2-methyl-cyclohexanonol may be produced through two paths, with activation energies slightly greater than that for the formation of 2-methyl-cyclohexanone. One path involves direct hydrogenation of the aromatic ring. Another path involves three steps, with the partial hydrogenation of the ring as the first step, hydrogen abstraction of the sbnd OH group as the second, and hydrogenation of remaining C atoms and the O atom the last.

  7. Study on the formation of peroxodisulfate ion on platinum anode using laser raman spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tasaka, Akimasa; Takenaka, Yutaka; Matsugidaira, Shin' ichi; Yasuzawa, Toru; Fujikawa, Toshiyuki; Sakamoto, Eibun

    1988-09-05

    In order to determine the reaction intermediates in the electrolysis formation of peroxodisulfate ion (S/sub 2/O/sub 8//sup 2/minus//), the galvanostatic oxidation of SO/sub 4//sup 2/minus// ion and HSO/sub 4//sup /minus// ion on platinum has been investigated in an H-shaped cell with a glass-filter. The electrolysis was carried out at constant curent density of 1 A/cm/sup 2/ in ammonium sulfate solution or mixed solution of ammonium sulfate and sulfuric acid. Produced S/sub 2/O/sub 8//sup 2/minus// or HSO/sub 5//sup /minus// was determined by both iodometry and permanganometry, whereas SO/sub 4//sup 2/minus// or HSO/sub 4//sup /minus// by the laser Raman spectrometry. On the formation of S/sub 2/O/sub 8//sup 2/minus//, it was revealed that not only SO/sub 4//sup -/ but also HSO/sub 4//sup /minus// will react and that the rate constant of S/sub 2/O/sub 8//sup 2/minus// formation from SO/sub 4//sup 2/minus// is about two times larger than that from HSO/sub 4//sup /minus//. 12 references, 7 figures, 3 tables.

  8. Oscillatory instabilities in the electrooxidation of borohydride on platinum

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Eduardo G.; Varela, Hamilton, E-mail: varela@iqsc.usp.br [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Instituto de Quimica

    2014-03-15

    The borohydride ion has been pointed as a promising alternative fuel. Most of the investigation on its electrochemistry is devoted to the electrocatalytic aspects of its electrooxidation on platinum and gold surfaces. Besides the known kinetic limitations and intricate mechanism, our Group has recently found the occurrence of two regions of bi-stability and autocatalysis in the electrode potential during the open circuit interaction of borohydride and oxidized platinum surfaces. Following this previous contribution, the occurrence of more complicated phenomena is here presented: namely the presence of electrochemical oscillations during the electrooxidation of borohydride on platinum in alkaline media. Current oscillations were found to be associated to two distinct instability windows and characterized in the resistance-potential parameter plane. The dynamic features of such oscillations suggest the existence of distinct mechanisms according to the potential region. Previously published results obtained under non-oscillatory regime were used to give some hints on the surface chemistry behind the observed dynamics. (author)

  9. Current View in Platinum Drug Mechanisms of Peripheral Neurotoxicity

    Directory of Open Access Journals (Sweden)

    Alessia Chiorazzi

    2015-08-01

    Full Text Available Peripheral neurotoxicity is the dose-limiting factor for clinical use of platinum derivatives, a class of anticancer drugs which includes cisplatin, carboplatin, and oxaliplatin. In particular cisplatin and oxaliplatin induce a severe peripheral neurotoxicity while carboplatin is less neurotoxic. The mechanisms proposed to explain these drugs’ neurotoxicity are dorsal root ganglia alteration, oxidative stress involvement, and mitochondrial dysfunction. Oxaliplatin also causes an acute and reversible neuropathy, supposed to be due by transient dysfunction of the voltage-gated sodium channels of sensory neurons. Recent studies suggest that individual genetic variation may play a role in the pathogenesis of platinum drug neurotoxicity. Even though all these mechanisms have been investigated, the pathogenesis is far from clearly defined. In this review we will summarize the current knowledge and the most up-to-date hypotheses on the mechanisms of platinum drug-induced peripheral neurotoxicity.

  10. Preparation of platinum/iridium scanning probe microscopy tips

    DEFF Research Database (Denmark)

    Sørensen, Alexis Hammer; Hvid, U.; Mortensen, M.W.

    1999-01-01

    for the production of sharp tips. After being etched the tips are ready for use in scanning tunneling microscopes, or they may be bent to form integrated tip/cantilever systems in ordinary commercial atomic force microscopes, being applicable as tapping mode tips and as electrostatic force microscopy tips. ©1999......We report on the development of an etching setup for use in the preparation of platinum/iridium tips for atomic force microscopy and scanning electrostatic force microscopy as well as scanning tunneling microscopy. The etching process is based on a two step electrochemical procedure. The first step....... This mechanism is based on the formation of oxygen and hydrogen at the platinum/iridium electrode when the potential is above the dissociation potential of water (~ 1.23 V) and storage of these products interstitially in the outer layers of the platinum wire. This leads to "microexplosions" that detach fragments...

  11. Platinum-Iridium Alloy Films Prepared by MOCVD

    Institute of Scientific and Technical Information of China (English)

    WEI Yan; CHEN Li; CAI Hongzhong; ZHENG Xu; YANG Xiya; HU Changyi

    2012-01-01

    Platinum-Iridium alloy films were prepared by MOCVD on Mo substrate using metal-acetylacetonate precursors.Effects of deposition conditions on composition,microstructure and mechanical properties were determined.In these experimental conditions,the purities of films are high and more than 99.0%.The films are homogeneous and monophase solid solution of Pt and Ir.Weight percentage of platinum are much higher than iridium in the alloy.Lattice constant of the alloy changes with the platinum composition.Iridium composition showing an up-down-up trend at the precursor temperature of 190~230℃ and the deposition temperature at 400~550℃.The hardness of Pt-Ir alloys prepared by MOCVD is three times more than the alloys prepared by casting.

  12. Interaction of DNA with Bis(diiminosuccinonitrilo)platinum(Ⅱ)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi-Gang; SUN Yuan-Yuan; JIANG Xiao-Ming

    2008-01-01

    Interaction of DNA with bis(diiminosuccinonitrilo)platinum(Ⅱ) has been studied by UV-visible absorbance spectra, fluorescence spectra and viscosity measurements. The UV-visible absorption spectra of the metal complex exhibit hypochromism with a small blue shift on interaction with DNA. Scatchard plot analyses indicate that the binding sites of the metal complex on DNA are different from those of ethidium bromide. Viscosity experiments reveal that the binding of the metal complex decreases the relative viscosity of DNA. These results suggest that the platinum diimine complex interact with DNA by surface binding. These studies are helpful for us to understand the action mechanism of bis(diiminosuccinonitrilo)platinum(Ⅱ) as a potential photodynamic therapeutic agent, and further to develop it.

  13. Synthesis and Electrocatalytic Performance of BDD-Supported Platinum Nanoparticles

    Science.gov (United States)

    Lyu, Xiao; Hu, Jingping; Foord, John S.; Lou, Changsheng; Zhang, Weiqiang

    2015-02-01

    Platinum nanoparticles were deposited on boron-doped diamond substrate by electroless method without pre-activation. The mechanism of this deposition is a galvanic process along with a chemical process. Platinum particles are in nanoscale with diameter around 30-50 nm and height of around 3 nm observed from AFM and SEM images. The electrochemical activity of Pt nanoparticles was evaluated by cyclic voltammograms of hydrogen desorption process in 0.5 M H2SO4. The deposited platinum shows great stability in subsequent cycling in sulfuric acid and exhibits a high selectivity toward H2O2 detection in the range of 1 to 400 μM compared with those produced by electrochemical deposition.

  14. Decitabine reactivated pathways in platinum resistant ovarian cancer.

    Science.gov (United States)

    Fang, Fang; Zuo, Qingyao; Pilrose, Jay; Wang, Yinu; Shen, Changyu; Li, Meng; Wulfridge, Phillip; Matei, Daniela; Nephew, Kenneth P

    2014-06-15

    Combination therapy with decitabine, a DNMTi and carboplatin resensitized chemoresistant ovarian cancer (OC) to platinum inducing promising clinical activity. We investigated gene-expression profiles in tumor biopsies to identify decitabine-reactivated pathways associated with clinical response. Gene-expression profiling was performed using RNA from paired tumor biopsies before and 8 days after decitabine from 17 patients with platinum resistant OC. Bioinformatic analysis included unsupervised hierarchical-clustering, pathway and GSEA distinguishing profiles of "responders" (progression-free survival, PFS>6 months) and "non-responders" (PFSdecitabine (TGF-β and Hh). Gene-expression profiling identified specific pathways altered by decitabine and associated with platinum-resensitization and clinical benefit in OC. Our data could influence patient stratification for future studies using epigenetic therapies.

  15. Sulphur hexafluoride gas detection

    CSIR Research Space (South Africa)

    Stolper, R

    2006-02-01

    Full Text Available This poster describes the development process of an electro-optical based solution for detecting and locating SF6 gas leaks at gas insulated switch gear. The principal technologies that were researched are explained with their advantages...

  16. Uranium hexafluoride public risk

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, D.R.; Hui, T.E.; Yurconic, M.; Johnson, J.R.

    1994-08-01

    The limiting value for uranium toxicity in a human being should be based on the concentration of uranium (U) in the kidneys. The threshold for nephrotoxicity appears to lie very near 3 {mu}g U per gram kidney tissue. There does not appear to be strong scientific support for any other improved estimate, either higher or lower than this, of the threshold for uranium nephrotoxicity in a human being. The value 3 {mu}g U per gram kidney is the concentration that results from a single intake of about 30 mg soluble uranium by inhalation (assuming the metabolism of a standard person). The concentration of uranium continues to increase in the kidneys after long-term, continuous (or chronic) exposure. After chronic intakes of soluble uranium by workers at the rate of 10 mg U per week, the concentration of uranium in the kidneys approaches and may even exceed the nephrotoxic limit of 3 {mu}g U per gram kidney tissue. Precise values of the kidney concentration depend on the biokinetic model and model parameters assumed for such a calculation. Since it is possible for the concentration of uranium in the kidneys to exceed 3 {mu}g per gram tissue at an intake rate of 10 mg U per week over long periods of time, we believe that the kidneys are protected from injury when intakes of soluble uranium at the rate of 10 mg U per week do not continue for more than two consecutive weeks. For long-term, continuous occupational exposure to low-level, soluble uranium, we recommend a reduced weekly intake limit of 5 mg uranium to prevent nephrotoxicity in workers. Our analysis shows that the nephrotoxic limit of 3 {mu}g U per gram kidney tissues is not exceeded after long-term, continuous uranium intake at the intake rate of 5 mg soluble uranium per week.

  17. Bioavailability of very finely distributed metallic platinum in the lungs and first orienting studies on effects. Part 2; Bioverfuegbarkeit von feinstverteiltem metallischem Platin in der Lunge und erste orientierende Wirkungsuntersuchungen (VPT 09; 2. Teil)

    Energy Technology Data Exchange (ETDEWEB)

    Emmendoerffer, A. [Fraunhofer-Institut fuer Toxikologie und Aerosolforschung, Hannover (Germany)

    1997-12-31

    Platinum is emitted from automotive catalytic converters in particulate form. The first organ to be exposed to it after its uptake by the organism is the lung. Lung macrophages therefore constitute the first barrier of the immune system which can to react to platinum. In this study the production of nitrogen oxides and cytokines was studied. These parameters play an important role in the initiation of inflammation and in the maintenance of chronic inflammatory processes that can lead to fibrosis of the lung. [Deutsch] Platin wird partikulaer aus Automobilabgaskatalysatoren emittiert. Das erste Zielorgan fuer eine Aufnahme im Organismus ist deshalb die Lunge. Die Lungenmakrophagen stellen also die erste Barriere des Immunsystems dar, das auf Platin reagieren kann. In vitro wurde die Produktion von Stickoxiden und Zytokinen untersucht. Diese Parameter spielen eine Rolle bei der Initiation von Entzuendungen und auch bei der Aufrechterhaltung chronisch entzuendlicher Prozesse, die in der Lunge zu einer Fibrose fuehren koennen. (orig.)

  18. Engineering Customized TALENs Using the Platinum Gate TALEN Kit.

    Science.gov (United States)

    Sakuma, Tetsushi; Yamamoto, Takashi

    2016-01-01

    Among various strategies for constructing customized transcription activator-like effector nucleases (TALENs), the Golden Gate assembly is the most widely used and most characterized method. The principle of Golden Gate assembly involves cycling reactions of digestion and ligation of multiple plasmids in a single tube, resulting in PCR-, fragmentation-, and purification-free concatemerization of DNA-binding repeats. Here, we describe the protocols for Golden Gate assembly-based TALEN construction using the Platinum Gate TALEN Kit, which allows generation of highly active Platinum TALENs.

  19. Distribution of platinum and cobalt atoms in a bimetallic nanoparticle

    Science.gov (United States)

    Chui, Yu Hang; Chan, Kwong-Yu

    2005-06-01

    Molecular dynamics simulations are performed to investigate the atomic distribution and the structure of platinum-cobalt nanoparticles. Heating and cooling techniques are applied before getting equilibrated structures at 298 K. Both crystalline (fcc) and amorphous structures are partly observed depending on cooling rates. The atomic distributions in different regions of a bimetallic nanoparticle are analyzed. Although platinum tends to occupy surface and near-surface sites of the bimetallic nanoparticle, a complete segregation to form a core-shell structure is not observed.

  20. Addition of platinum and silver nanoparticles to toughen dental porcelain.

    Science.gov (United States)

    Fujieda, Tokushi; Uno, Mitsunori; Ishigami, Hajime; Kurachi, Masakazu; Wakamatsu, Nobukazu; Doi, Yutaka

    2012-01-01

    Several studies have investigated toughening porcelain that is layered over a frame or a core. The introduction of residual compressive stress to the surface of porcelain has been shown to be effective to strengthen it. In the present study, nanoparticles of precious metals of silver and platinum (rather than non-precious metals) were used to evaluate if they could increase the fracture resistance of porcelain. The addition of silver and platinum nanoparticles was found to improve the mechanical properties of porcelain since it increased both the Young's modulus and the fracture toughness of commercial porcelain.

  1. Diffuse X-Ray Scattering from Several Platinum Chain Compounds

    DEFF Research Database (Denmark)

    Braude, A.; Lindegaard-Andersen, Asger; Carneiro, K.

    1980-01-01

    Values of the Fermi wavevector for several platinum based one-dimensional conductors were determined from diffuse X-ray scattering measurements. The values were compared with those expected from the chemical compositions. The importance of conclusive values of this parameter is stressed and the c......Values of the Fermi wavevector for several platinum based one-dimensional conductors were determined from diffuse X-ray scattering measurements. The values were compared with those expected from the chemical compositions. The importance of conclusive values of this parameter is stressed...

  2. Synthesis of platinum nanoparticle electrocatalysts by atomic layer deposition

    Science.gov (United States)

    Lubers, Alia Marie

    Demand for energy continues to increase, and without alternatives to fossil fuel combustion the effects on our environment will become increasingly severe. Fuel cells offer a promising improvement on current methods of energy generation; they are able to convert hydrogen fuel into electricity with a theoretical efficiency of up to 83% and interface smoothly with renewable hydrogen production. Fuel cells can replace internal combustion engines in vehicles and are used in stationary applications to power homes and businesses. The efficiency of a fuel cell is maximized by its catalyst, which is often composed of platinum nanoparticles supported on carbon. Economical production of fuel cell catalysts will promote adoption of this technology. Atomic layer deposition (ALD) is a possible method for producing catalysts at a large scale when employed in a fluidized bed. ALD relies on sequential dosing of gas-phase precursors to grow a material layer by layer. We have synthesized platinum nanoparticles on a carbon particle support (Pt/C) by ALD for use in proton exchange membrane fuel cells (PEMFCs) and electrochemical hydrogen pumps. Platinum nanoparticles with different characteristics were deposited by changing two chemistries: the carbon substrate through functionalization; and the deposition process by use of either oxygen or hydrogen as ligand removing reactants. The metal depositing reactant was trimethyl(methylcyclopentadienyl)platinum(IV). Functionalizing the carbon substrate increased nucleation during deposition resulting in smaller and more dispersed nanoparticles. Use of hydrogen produced smaller nanoparticles than oxygen, due to a gentler hydrogenation reaction compared to using oxygen's destructive combustion reaction. Synthesized Pt/C materials were used as catalysts in an electrochemical hydrogen pump, a device used to separate hydrogen fuel from contaminants. Catalysts deposited by ALD on functionalized carbon using a hydrogen chemistry were the most

  3. Effects of Cluster Size on Platinum-Oxygen Bonds Formation in Small Platinum Clusters

    Science.gov (United States)

    Oemry, Ferensa; Padama, Allan Abraham B.; Kishi, Hirofumi; Kunikata, Shinichi; Nakanishi, Hiroshi; Kasai, Hideaki; Maekawa, Hiroyoshi; Osumi, Kazuo; Sato, Kaoru

    2012-03-01

    We present the results of density functional theory calculation in oxygen dissociative adsorption process on two types of isolated platinum (Pt) clusters: Pt4 and Pt10, by taking into account the effect of cluster reconstruction. The strength of Pt-Pt bonds in the clusters is mainly defined by d-d hybridization and interstitial bonding orbitals (IBO). Oxygen that adsorbed on the clusters is weakening the IBO and thus inducing geometry reconstruction as occurred in Pt10 cluster. However, cluster that could undergo structural deformation is found to promote oxygen dissociation with no energy barrier. The details show that maintaining well-balanced of attractive and repulsive (Hellmann-Feynman) forces between atoms is considered to be the main key to avoid any considerable rise of energy barrier. Furthermore, a modest energy barrier that gained in Pt4 cluster is presumed to be originate from inequality of intramolecular forces between atoms.

  4. Preparation of MgO supported platinum nanoparticle catalyst using toluene dispersed platinum sol

    Science.gov (United States)

    Seth, Jhumur; Nepak, Devadutta; Chaudhari, Vijay R.; Prasad, Bhagavatula L. V.

    2017-10-01

    An effective way of anchoring Pt nanoparticles on MgO using toluene dispersed platinum nanoparticles (Pt-NPs) as one of the ingredient is demonstrated. The usage of particles dispersed in toluene allows the retention of size and size distribution of preformed Pt-NPs even after deposition on MgO support with high active surface area, which is crucial for heterogeneous catalysis. The catalyst thus prepared, displayed selective hydrogenation of cinnamaldehyde to cinnamyl alcohol with high turn on frequency (TOF - 105 h-1) with respect to the total Pt content. We attribute this efficient catalytic performance to the uniform distribution and deposition of Pt on the active MgO support and its better accessible surface as evidenced by the cyclic-voltammetry results.

  5. Use of 25% sulfur hexafluoride gas mixture may minimize short-term postoperative hypotony in sutureless 25-gauge pars plana vitrectomy surgery

    Directory of Open Access Journals (Sweden)

    Barak Y

    2013-02-01

    Full Text Available Yoreh Barak, James W Heroman, Shlomit SchaalDepartment of Ophthalmology and Visual Sciences, University of Louisville, Louisville, KY, USABackground: The purpose of this study was to compare postoperative intraocular pressures and percentage of vitreous cavity gas fill one day following 25-gauge pars plana vitrectomy with 20% versus 25% sulfur hexafluoride (SF6 gas fill.Methods: This was a retrospective review of 187 consecutive cases of 25-gauge pars plana vitrectomy with complete fluid/gas exchange. The main outcome measures included percentage of gas fill of the vitreous cavity and intraocular pressure on postoperative day one.Results: Fifty eyes underwent 25-gauge pars plana vitrectomy with 20% SF6 tamponade and 137 with 25% SF6 tamponade. On postoperative day one in the 20% SF6 group, there were five (10% patients with hypotony (intraocular pressure ≤ 5 mmHg and none in the 25% SF6 group. Mean intraocular pressure was 9 ± 2.5 mmHg and 16.8 ± 2.4 mmHg for the 20% SF6 and 25% SF6 groups, respectively (P < 0.01. None of the patients had postoperative intraocular pressure > 23 mmHg. Mean vitreous cavity gas fill on postoperative day one was 70.7% ± 10% in the 20% SF6 group and 89.5% ± 2.2% in the 25% SF6 group (P < 0.01. There was no difference in the number of phakic patients needing cataract surgery between the groups.Conclusion: A slightly expansile concentration of 25% SF6 gas can be safely and beneficially used in 25-gauge vitrectomy surgery to increase the amount of gas fill in the vitreous cavity and prevent postoperative hypotony.Keywords: hypotony, 25-gauge pars plana vitrectomy, sulfur hexafluoride

  6. Off-label-use of sulfur-hexafluoride in voiding urosonography for diagnosis of vesicoureteral reflux in children: A survey on adverse events

    Science.gov (United States)

    Sauer, Alexander; Wirth, Clemens; Platzer, Isabel; Neubauer, Henning; Veldhoen, Simon; Dierks, Alexander; Kaiser, Reinhard; Kunz, Andreas; Beer, Meinrad; Bley, Thorsten

    2017-01-01

    AIM To evaluate the risk profile of sulfur hexafluoride in voiding urosonography (VUS) based on a large cohort of children. METHODS Since 2011 sulfur hexafluoride (SH, SonoVue®, Bracco, Italy) is the only ultrasound contrast available in the European Union and its use in children has not been approved. Within a 4-year-period, 531 children with suspected or proven vesicoureteral reflux (f/m = 478/53; mean age 4.9 years; 1 mo-25.2 years) following parental informed consent underwent VUS with administration of 2.6 ± 1.2 mL SH in a two-center study. A standardized telephone survey on adverse events was conducted three days later. RESULTS No acute adverse reactions were observed. The survey revealed subacute, mostly self-limited adverse events in 4.1% (22/531). The majority of observed adverse events (17/22) was not suspected to be caused by an allergic reaction: Five were related to catheter placement, three to reactivated urinary tract infections, five were associated with perineal disinfection before voiding urosonography or perineal dermatitis and four with a common cold. In five patients (0.9%) hints to a potential allergic cause were noted: Perineal urticaria was reported in three interviews and isolated, mild fever in two. These were minor self-limited adverse events with a subacute onset and no hospital admittance was necessary. Ninety-six point two percent of the parents would prefer future VUS examinations with use of SH. CONCLUSION No severe adverse events were observed and indications of self-limited minor allergic reactions related to intravesical administration of SH were reported in less than 1%. PMID:28224096

  7. Biological assessment of the effects of construction and operation of a depleted uranium hexafluoride conversion facility at the Paducah, Kentucky, site.

    Energy Technology Data Exchange (ETDEWEB)

    Van Lonkhuyzen, R.

    2005-09-09

    The U.S. Department of Energy (DOE) Depleted Uranium Hexafluoride (DUF{sub 6}) Management Program evaluated alternatives for managing its inventory of DUF{sub 6} and issued the ''Programmatic Environmental Impact Statement for Alternative Strategies for the Long-Term Management and Use of Depleted Uranium Hexafluoride'' (DUF{sub 6} PEIS) in April 1999 (DOE 1999). The DUF{sub 6} inventory is stored in cylinders at three DOE sites: Paducah, Kentucky; Portsmouth, Ohio; and East Tennessee Technology Park (ETTP), near Oak Ridge, Tennessee. In the Record of Decision for the DUF{sub 6} PEIS, DOE stated its decision to promptly convert the DUF6 inventory to a more stable chemical form. Subsequently, the U.S. Congress passed, and the President signed, the ''2002 Supplemental Appropriations Act for Further Recovery from and Response to Terrorist Attacks on the United States'' (Public Law No. 107-206). This law stipulated in part that, within 30 days of enactment, DOE must award a contract for the design, construction, and operation of a DUF{sub 6} conversion plant at the Department's Paducah, Kentucky, and Portsmouth, Ohio, sites, and for the shipment of DUF{sub 6} cylinders stored at ETTP to the Portsmouth site for conversion. This biological assessment (BA) has been prepared by DOE, pursuant to the National Environmental Policy Act of 1969 (NEPA) and the Endangered Species Act of 1974, to evaluate potential impacts to federally listed species from the construction and operation of a conversion facility at the DOE Paducah site.

  8. Effect of Rotation Rate on the Formation of Platinum-modified Polyaniline Film and Electrocatalytic Oxidation of Methanol

    Institute of Scientific and Technical Information of China (English)

    Qiu Hong LI; Lin NIU; Chang Qiao ZHANG; Feng Hua WEI; Hu ZHANG

    2004-01-01

    The oxidation of methanol was investigated on platinum-modified polyaniline electrode. Changes in the electrode rotation rates (Ω) during platinum electrodeposition remarkably affect the formation and distribution of platinum in the polymer matrix and consequently lead to different currents of methanol oxidation. The results show that platinum loading is proportional to rotation ratesΩ1/2.

  9. Physical and electrochemical study of platinum thin films deposited by sputtering and electrochemical methods

    Energy Technology Data Exchange (ETDEWEB)

    Quinones, C. [Universidad de Cartagena, Cartagena de Indias (Colombia); Departamento de Quimica, Universidad Nacional de Colombia, Cra. 30 No 45-03, Bogota (Colombia); Vallejo, W., E-mail: wavallejol@unal.edu.co [Departamento de Quimica, Universidad Nacional de Colombia, Cra. 30 No 45-03, Bogota (Colombia); Mesa, F. [Departamento de Ciencias Basicas, Universidad Libre, Carrera 70 No 53-40, Bogota (Colombia)

    2011-06-15

    In this work platinum thin films deposited by sputtering and electrochemical methods were characterized through physical and electrochemical analysis. The as-grown platinum thin films were characterized through X-ray diffraction (XRD), atomic force microscopy (AFM); scanning electronic microscopy (SEM) and through electrochemical impedance spectroscopy (EIS) measurements. Structural studies indicated that platinum thin films were polycrystalline. Morphological characteristics were significantly affected by the substrate type and synthesis method. Finally the EIS analysis indicated that platinum films were electrochemically stable and present both low resistance of charge transfer and low series resistance; the equivalent circuit of platinum interface has been proposed.

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

    Science.gov (United States)

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

    2012-01-01

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

  11. [Comparison of the effectiveness of platinum-based chemotherapy versus non-platinum-based chemotherapy for triple-negative breast cancer with metastases confined to the lungs].

    Science.gov (United States)

    Hong, Ruoxi; Ma, Fei; Shi, Xiuqing; Li, Qing; Zhang, Pin; Yuan, Peng; Wang, Jiayu; Fan, Ying; Cai, Ruigang; Li, Qiao; Xu, Binghe

    2014-10-01

    To compare the effect of first-line treatment with platinum-based chemotherapy and non-platinum-based chemotherapy in patients with lung metastases from triple negative breast cancer (TNBC). Sixty-five eligible patients were divided into platinum-treated group and non-platinum-treated group according to the first-line therapy. Factors predicting the chemotherapeutic efficacy included overall survival (OS), progression-free survival (PFS) and objective response (OR). In the platinum-treated group of 32 patients, 2 cases (6.3%) achieved CR, 16 cases (50.0%) achieved PR, 11 (34.4%) cases achieved SD, and 3 patients (9.4%) achieved PD. In the non-platinum-treated group of 33 patients, 2 cases (6.1%) achieved CR, 6 cases (18.2%) achieved PR, 16 cases (48.5%) achieved SD, and 9 cases (27.3%) achieved PD. Median PFS was significantly longer in the platinum-treated group than in the non-platinum-treated group (10 months vs. 6.0 months, P = 0.012), and OS was also improved (32 months vs. 22 months, P = 0.006). Multivariate analysis of several factors including local-regional lymph node involvement, lung metastasis-related symptoms, first-line platinum-based chemotherapy, disease-free interval, size and number of lung lesions, showed that first-line platinum-based chemotherapy was an independent prognostic factor for TNBC patients with lung metastases. Compared with non-platinum-based chemotherapy, the first-line platinum-based chemotherapy can improve PFS and OS in TNBC patients with metastases confined to the lungs.

  12. Single-Atom Catalyst of Platinum Supported on Titanium Nitride for Selective Electrochemical Reactions.

    Science.gov (United States)

    Yang, Sungeun; Kim, Jiwhan; Tak, Young Joo; Soon, Aloysius; Lee, Hyunjoo

    2016-02-05

    As a catalyst, single-atom platinum may provide an ideal structure for platinum minimization. Herein, a single-atom catalyst of platinum supported on titanium nitride nanoparticles were successfully prepared with the aid of chlorine ligands. Unlike platinum nanoparticles, the single-atom active sites predominantly produced hydrogen peroxide in the electrochemical oxygen reduction with the highest mass activity reported so far. The electrocatalytic oxidation of small organic molecules, such as formic acid and methanol, also exhibited unique selectivity on the single-atom platinum catalyst. A lack of platinum ensemble sites changed the reaction pathway for the oxygen-reduction reaction toward a two-electron pathway and formic acid oxidation toward direct dehydrogenation, and also induced no activity for the methanol oxidation. This work demonstrates that single-atom platinum can be an efficient electrocatalyst with high mass activity and unique selectivity.

  13. Ambulatory REACT: real-time seizure detection with a DSP microprocessor.

    Science.gov (United States)

    McEvoy, Robert P; Faul, Stephen; Marnane, William P

    2010-01-01

    REACT (Real-Time EEG Analysis for event deteCTion) is a Support Vector Machine based technology which, in recent years, has been successfully applied to the problem of automated seizure detection in both adults and neonates. This paper describes the implementation of REACT on a commercial DSP microprocessor; the Analog Devices Blackfin®. The primary aim of this work is to develop a prototype system for use in ambulatory or in-ward automated EEG analysis. Furthermore, the complexity of the various stages of the REACT algorithm on the Blackfin processor is analysed; in particular the EEG feature extraction stages. This hardware profile is used to select a reduced, platform-aware feature set, in order to evaluate the seizure classification accuracy of a lower-complexity, lower-power REACT system.

  14. Rule-Based Multidisciplinary Tool for Unsteady Reacting Real-Fluid Flows Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A design and analysis computational tool is proposed for simulating unsteady reacting flows in combustor devices used in reusable launch vehicles. Key aspects...

  15. A Density Functional Study of Bare and Hydrogenated Platinum Clusters

    CERN Document Server

    Sebetci, A

    2006-01-01

    We perform density functional theory calculations using Gaussian atomic-orbital methods within the generalized gradient approximation for the exchange and correlation to study the interactions in the bare and hydrogenated platinum clusters. The minimum-energy structures, binding energies, relative stabilities, vibrational frequencies and the highest occupied and lowest unoccupied molecular-orbital gaps of Pt_nH_m (n=1-5, m=0-2) clusters are calculated and compared with previously studied pure platinum and hydrogenated platinum clusters. We investigate any magic behavior in hydrogenated platinum clusters and find that Pt_4H_2 is more stable than its neighboring sizes. Our results do not agree with a previous conclusion that 3D geometries of Pt tetramer and pentamer are unfavored. On the contrary, the lowest energy structure of Pt_4 is found to be a distorted tetrahedron and that of Pt_5 is found to be a bridge site capped tetrahedron which is a new global minimum for Pt_5 cluster. The successive addition of H ...

  16. In situ measurements of Merensky pillar behaviour at Impala Platinum

    CSIR Research Space (South Africa)

    Watson, BP

    2009-12-01

    Full Text Available to stabilize the stoping excavations. This paper describes the in situ measurement, of stress within a Merensky pillar from Impala Platinum. These measurements were used to derive a stress-strain curve that includes pre and post failure behaviour. 2D FLAC...

  17. EGFR-targeting peptide-coupled platinum(IV) complexes.

    Science.gov (United States)

    Mayr, Josef; Hager, Sonja; Koblmüller, Bettina; Klose, Matthias H M; Holste, Katharina; Fischer, Britta; Pelivan, Karla; Berger, Walter; Heffeter, Petra; Kowol, Christian R; Keppler, Bernhard K

    2017-06-01

    The high mortality rate of lung cancer patients and the frequent occurrence of side effects during cancer therapy demonstrate the need for more selective and targeted drugs. An important and well-established target for lung cancer treatment is the occasionally mutated epidermal growth factor receptor (EGFR). As platinum(II) drugs are still the most important therapeutics against lung cancer, we synthesized in this study the first platinum(IV) complexes coupled to the EGFR-targeting peptide LARLLT (and the shuffled RTALLL as reference). Notably, HPLC-MS measurements revealed two different peaks with the same molecular mass, which turned out to be a transcyclization reaction in the linker between maleimide and the coupled cysteine moiety. With regard to the EGFR specificity, subsequent biological investigations (3-day viability, 14-day clonogenic assays and platinum uptake) on four different cell lines with different verified EGFR expression levels were performed. Unexpectedly, the results showed neither an enhanced activity nor an EGFR expression-dependent uptake of our new compounds. Consequently, fluorophore-coupled peptides were synthesized to re-evaluate the targeting ability of LARLLT itself. However, also with these molecules, flow cytometry measurements showed no correlation of drug uptake with the EGFR expression levels. Taken together, we successfully synthesized the first platinum(IV) complexes coupled to an EGFR-targeting peptide; however, the biological investigations revealed that LARLLT is not an appropriate peptide for enhancing the specific uptake of small-molecule drugs into EGFR-overexpressing cancer cells.

  18. Electroreduction of cefetamet on mercury platinum and gold electrodes

    Directory of Open Access Journals (Sweden)

    P. ZUMAN

    2000-01-01

    Full Text Available The electroreduction of cefetamet (CEF using gold and platinum electrodes has been investigated in slightly alkaline medium (pH 8.40 where adsorption, previously observed at mercury electrode, was pronounced. This investigation was performed in order to determine whether the adsorption interfers with the reduction process even at solid electrodes and to compare with a mercury electrode.

  19. Platinum on Carbon Nanofibers as Catalyst for Cinnamaldehyde Hydrogenation

    NARCIS (Netherlands)

    Plomp, A.J.

    2009-01-01

    The aim of the work described in this thesis was to investigate the role and nature of nanostructured carbon materials, oxygen surface groups and promoters on platinum-based catalysts for the selective hydrogenation of cinnamaldehyde. The selective hydrogenation of cinnamaldehyde to cinnamyl alcohol

  20. Platinum redispersion on metal oxides in low temperature fuel cells

    DEFF Research Database (Denmark)

    Tripkovic, Vladimir; Cerri, Isotta; Nagami, Tetsuo

    2013-01-01

    in detail; however, due to different operating conditions it is not straightforward to link the chemical and the electrochemical environment. The largest differences reflect in (1) the oxidation state of the surface (the oxygen species coverage), (2) temperature and (3) the possibility of platinum...

  1. Preparation of low-platinum-content platinum-nickel, platinum-cobalt binary alloy and platinum-nickel-cobalt ternary alloy catalysts for oxygen reduction reaction in polymer electrolyte fuel cells

    Science.gov (United States)

    Li, Mu; Lei, Yanhua; Sheng, Nan; Ohtsuka, Toshiaki

    2015-10-01

    A series of low-platinum-content platinum-nickel (Pt-Ni), platinum-cobalt (Pt-Co) binary alloys and platinum-nickel-cobalt (Pt-Ni-Co) ternary alloys electrocatalysts were successfully prepared by a three-step process based on electrodeposition technique and studied as electrocatalysts for oxygen reduction reaction (ORR) in polymer-electrolyte fuel cells. Kinetics of ORR was studied in 0.5 M H2SO4 solution on the Pt-Ni, Pt-Co and Pt-Ni-Co alloys catalysts using rotating disk electrode technique. Both the series of Pt-Ni, Pt-Co binary alloys and the Pt-Ni-Co ternary alloys catalysts exhibited an obvious enhancement of ORR activity in comparison with pure Pt. The significant promotion of ORR activities of Pt-Ni and Pt-Co binary alloys was attributed to the enhancement of the first electron-transfer step, whereas, Pt-Ni-Co ternary alloys presented a more complicated mechanism during the electrocatalysis process but a much more efficient ORR activities than the binary alloys.

  2. Polyamide platinum anticancer complexes designed to target specific DNA sequences.

    Science.gov (United States)

    Jaramillo, David; Wheate, Nial J; Ralph, Stephen F; Howard, Warren A; Tor, Yitzhak; Aldrich-Wright, Janice R

    2006-07-24

    Two new platinum complexes, trans-chlorodiammine[N-(2-aminoethyl)-4-[4-(N-methylimidazole-2-carboxamido)-N-methylpyrrole-2-carboxamido]-N-methylpyrrole-2-carboxamide]platinum(II) chloride (DJ1953-2) and trans-chlorodiammine[N-(6-aminohexyl)-4-[4-(N-methylimidazole-2-carboxamido)-N-methylpyrrole-2-carboxamido]-N-methylpyrrole-2-carboxamide]platinum(II) chloride (DJ1953-6) have been synthesized as proof-of-concept molecules in the design of agents that can specifically target genes in DNA. Coordinate covalent binding to DNA was demonstrated with electrospray ionization mass spectrometry. Using circular dichroism, these complexes were found to show greater DNA binding affinity to the target sequence: d(CATTGTCAGAC)(2), than toward either d(GTCTGTCAATG)(2,) which contains different flanking sequences, or d(CATTGAGAGAC)(2), which contains a double base pair mismatch sequence. DJ1953-2 unwinds the DNA helix by around 13 degrees , but neither metal complex significantly affects the DNA melting temperature. Unlike simple DNA minor groove binders, DJ1953-2 is able to inhibit, in vitro, RNA synthesis. The cytotoxicity of both metal complexes in the L1210 murine leukaemia cell line was also determined, with DJ1953-6 (34 microM) more active than DJ1953-2 (>50 microM). These results demonstrate the potential of polyamide platinum complexes and provide the structural basis for designer agents that are able to recognize biologically relevant sequences and prevent DNA transcription and replication.

  3. Molecular pathways: the immunogenic effects of platinum-based chemotherapeutics

    NARCIS (Netherlands)

    Hato, S.V.; Khong, A.; Vries, I.J.M. de; Lesterhuis, W.J.

    2014-01-01

    The platinum-based drugs cisplatin, carboplatin, and oxaliplatin belong to the most widely used chemotherapeutics in oncology, showing clinical efficacy against many solid tumors. Their main mechanism of action is believed to be the induction of cancer cell apoptosis as a response to their covalent

  4. Effect of heat leaks in platinum resistance thermometry.

    Science.gov (United States)

    Goldratt, E; Yeshurun, Y; Greenfield, A J

    1980-03-01

    The effect of heat leaks in platinum resistance thermometry is analyzed. An experimental method is proposed for estimating the magnitude of this effect. Results are reported for the measurement of the temperature of a hot, solid body under different heat-leak configurations. Design criteria for thermometers are presented which minimize the effect of such heat leaks.

  5. Production of platinum radioisotopes at Brookhaven Linac Isotope Producer (BLIP

    Directory of Open Access Journals (Sweden)

    Smith Suzanne V.

    2017-01-01

    Full Text Available The accelerator production of platinum isotopes was investigated at the Brookhaven Linac Isotope Producer (BLIP. In this study high purity natural platinum foils were irradiated at 53.2, 65.7, 105.2, 151.9, 162.9 and 173.3.MeV. The irradiated foils were digested in aqua regia and then converted to their hydrochloride salt with concentrated hydrochloric acid before analyzing by gamma spectrometry periodically for at least 10 days post end of bombardment. A wide range of platinum (Pt, gold (Au and iridium (Ir isotopes were identified. Effective cross sections at BLIP for Pt-188, Pt-189, Pt-191 and Pt-195m were compared to literature and theoretical cross sections determined using Empire-3.2. The majority of the effective cross sections (<70 MeV confirm those reported in the literature. While the absolute values of the theoretical cross sections were up to a factor of 3 lower, Empire 3.2 modeled thresholds and maxima correlated well with experimental values. Preliminary evaluation into a rapid separation of Pt isotopes from high levels of Ir and Au isotopes proved to be a promising approach for large scale production. In conclusion, this study demonstrated that with the use of isotopically enriched target material accelerator production of selected platinum isotopes is feasible over a wide proton energy range.

  6. A Multimethod Approach for Investigating Algal Toxicity of Platinum Nanoparticles

    DEFF Research Database (Denmark)

    Sørensen, Sara Nørgaard; Engelbrekt, Christian; Lützhøft, Hans-Christian Holten

    2016-01-01

    The ecotoxicity of platinum nanoparticles (PtNPs) widely used in for example automotive catalytic converters, is largely unknown. This study employs various characterization techniques and toxicity end points to investigate PtNP toxicity toward the green microalgae Pseudokirchneriella subcapitata...

  7. Responses of fibroblasts and glial cells to nanostructured platinum surfaces

    Science.gov (United States)

    Pennisi, C. P.; Sevcencu, C.; Dolatshahi-Pirouz, A.; Foss, M.; Lundsgaard Hansen, J.; Nylandsted Larsen, A.; Zachar, V.; Besenbacher, F.; Yoshida, K.

    2009-09-01

    The chronic performance of implantable neural prostheses is affected by the growth of encapsulation tissue onto the stimulation electrodes. Encapsulation is associated with activation of connective tissue cells at the electrode's metallic contacts, usually made of platinum. Since surface nanotopography can modulate the cellular responses to materials, the aim of the present work was to evaluate the 'in vitro' responses of connective tissue cells to platinum strictly by modulating its surface nanoroughness. Using molecular beam epitaxy combined with sputtering, we produced platinum nanostructured substrates consisting of irregularly distributed nanopyramids and investigated their effect on the proliferation, cytoskeletal organization and cellular morphology of primary fibroblasts and transformed glial cells. Cells were cultured on these substrates and their responses to surface roughness were studied. After one day in culture, the fibroblasts were more elongated and their cytoskeleton less mature when cultured on rough substrates. This effect increased as the roughness of the surface increased and was associated with reduced cell proliferation throughout the observation period (4 days). Morphological changes also occurred in glial cells, but they were triggered by a different roughness scale and did not affect cellular proliferation. In conclusion, surface nanotopography modulates the responses of fibroblasts and glial cells to platinum, which may be an important factor in optimizing the tissue response to implanted neural electrodes.

  8. Enhancement of Platinum Cathode Catalysis by Addition of Transition Metals

    Science.gov (United States)

    Duong, Hung Tuan

    2009-01-01

    The sluggish kinetics of oxygen reduction reaction (ORR) contributes significantly to the loss of cathode overpotential in fuel cells, thus requiring high loadings of platinum (Pt), which is an expensive metal with limited supply. However, Pt and Pt-based alloys are still the best available electrocatalysts for ORR thus far. The research presented…

  9. Platinum on Carbon Nanofibers as Catalyst for Cinnamaldehyde Hydrogenation

    NARCIS (Netherlands)

    Plomp, A.J.

    2009-01-01

    The aim of the work described in this thesis was to investigate the role and nature of nanostructured carbon materials, oxygen surface groups and promoters on platinum-based catalysts for the selective hydrogenation of cinnamaldehyde. The selective hydrogenation of cinnamaldehyde to cinnamyl alcohol

  10. SILICA-BOUND CROWN ETHERS PLATINUM COMPLEX AS HYDROSILYLATION CATALYST

    Institute of Scientific and Technical Information of China (English)

    CHEN Yuanyin; MENG Lingzhi; LI Liping; LUO Jieqi; HU Jinchang

    1993-01-01

    Silica-bound 15-Crown-5, 18-Crown-6 with a spacer of propyloxymethyl and their platinum complexes have been synthesized. It was found that they were efficient catalysts for the hydrosilylation of olefins with triethoxysilane in the temperature range of 60 to 130 ℃ .

  11. Niraparib Maintenance Therapy in Platinum-Sensitive, Recurrent Ovarian Cancer

    DEFF Research Database (Denmark)

    Mirza, Mansoor R; Monk, Bradley J; Herrstedt, Jørn

    2016-01-01

    Background Niraparib is an oral poly(adenosine diphosphate [ADP]-ribose) polymerase (PARP) 1/2 inhibitor that has shown clinical activity in patients with ovarian cancer. We sought to evaluate the efficacy of niraparib versus placebo as maintenance treatment for patients with platinum-sensitive, ...

  12. KEEFEKTIFAN STRATEGI REACT DITINJAU DARI PRESTASI BELAJAR, KEMAMPUAN PENYELESAIAN MASALAH, KONEKSI MATEMATIS, SELF EFFICACY

    Directory of Open Access Journals (Sweden)

    Runtyani Irjayanti Putri

    2015-11-01

    Full Text Available Penelitian ini bertujuan untuk: (1 mendeskripsikan keefektifan strategi pembelajaran REACT pada pembelajaran turunan fungsi ditinjau dari prestasi belajar matematika, kemampuan penyelesaian masalah matematis, kemampuan koneksi matematis, dan Self efficacy siswa SMA Negeri 4 Magelang, (2 menentukan strategi pembelajaran yang lebih efektif diantara strategi REACT dan pembelajaran konvensional pada pembelajaran turunan fungsi ditinjau dari aspek prestasi belajar matematika, kemampuan penyelesaian masalah matematis, kemampuan koneksi matematis, dan Self efficacy siswa SMA Negeri 4 Magelang. Penelitian ini adalah penelitian quasi experiment. Teknik pengumpulan data yang digunakan adalah teknik tes dan nontes. Teknik analisis data yang digunakan adalah uji one sample t-test, uji T2 Hotelling’s, dan uji t-Bonferroni. Hasil penelitian menunjukkan bahwa: (1 strategi pembelajaran REACT efektif pada pembelajaran turunan fungsi ditinjau dari prestasi belajar matematika, kemampuan penyelesaian masalah matematis, kemampuan koneksi matematis, dan Self efficacy siswa SMA Negeri 4 Magelang, dan (2 strategi pembelajaran REACT lebih efektif daripada pembelajaran konvensional pada pembelajaran turunan fungsi ditinjau dari aspek prestasi belajar matematika, kemampuan penyelesaian masalah matematis, kemampuan koneksi matematis, dan Self efficacy siswa SMA Negeri 4 Magelang. Kata Kunci: strategi REACT, prestasi belajar, kemampuan penyelesaian masalah matematis, kemampuan koneksi matematis, dan Self efficacy siswa SMA   THE EFFECTIVENESS OF REACT STRATEGY VIEWED FROM LEARNING ACHIEVEMENT, PROBLEM SOLVING ABILITY, MATHEMATICAL CONNECTION, SELF EFFICACY Abstract The aims of this study are to: (1 to describe the effectiveness of the REACT strategy viewed from Mathematics Learning Achievement, Mathematics Problem Solving Ability, Mathematics Connection Ability, and Student Self efficacy of State Senior High School 4 Magelang Students, and (2 determine a more effective

  13. Tissue Platinum Concentration and Tumor Response in Non–Small-Cell Lung Cancer

    Science.gov (United States)

    Kim, Eric S.; Lee, J. Jack; He, Guangan; Chow, Chi-Wan; Fujimoto, Junya; Kalhor, Neda; Swisher, Stephen G.; Wistuba, Ignacio I.; Stewart, David J.; Siddik, Zahid H.

    2012-01-01

    Purpose Platinum resistance is a major limitation in the treatment of advanced non–small-cell lung cancer (NSCLC). Reduced intracellular drug accumulation is one of the most consistently identified features of platinum-resistant cell lines, but clinical data are limited. We assessed the effects of tissue platinum concentrations on response and survival in NSCLC. Patients and Methods We measured total platinum concentrations by flameless atomic absorption spectrophotometry in 44 archived fresh-frozen NSCLC specimens from patients who underwent surgical resection after neoadjuvant platinum-based chemotherapy. Tissue platinum concentration was correlated with percent reduction in tumor size on post- versus prechemotherapy computed tomography scans. The relationship between tissue platinum concentration and survival was assessed by univariate and multicovariate Cox proportional hazards regression model analysis and Kaplan-Meier analysis. Results Tissue platinum concentration correlated significantly with percent reduction in tumor size (P < .001). The same correlations were seen with cisplatin, carboplatin, and all histology subgroups. Furthermore, there was no significant impact of potential variables such as number of cycles and time lapse from last chemotherapy on platinum concentration. Patients with higher platinum concentration had longer time to recurrence (P = .034), progression-free survival (P = .018), and overall survival (P = .005) in the multicovariate Cox model analysis after adjusting for number of cycles. Conclusion This clinical study established a relationship between tissue platinum concentration and response in NSCLC. It suggests that reduced platinum accumulation might be an important mechanism of platinum resistance in the clinical setting. Further studies investigating factors that modulate intracellular platinum concentration are warranted. PMID:22891266

  14. Self-Reacting Friction Stir Welding for Aluminum Alloy Circumferential Weld Applications

    Science.gov (United States)

    Bjorkman, Gerry; Cantrell, Mark; Carter, Robert

    2003-01-01

    Friction stir welding is an innovative weld process that continues to grow in use, in the commercial, defense, and space sectors. It produces high quality and high strength welds in aluminum alloys. The process consists of a rotating weld pin tool that plasticizes material through friction. The plasticized material is welded by applying a high weld forge force through the weld pin tool against the material during pin tool rotation. The high weld forge force is reacted against an anvil and a stout tool structure. A variation of friction stir welding currently being evaluated is self-reacting friction stir welding. Self-reacting friction stir welding incorporates two opposing shoulders on the crown and root sides of the weld joint. In self-reacting friction stir welding, the weld forge force is reacted against the crown shoulder portion of the weld pin tool by the root shoulder. This eliminates the need for a stout tooling structure to react the high weld forge force required in the typical friction stir weld process. Therefore, the self-reacting feature reduces tooling requirements and, therefore, process implementation costs. This makes the process attractive for aluminum alloy circumferential weld applications. To evaluate the application of self-reacting friction stir welding for aluminum alloy circumferential welding, a feasibility study was performed. The study consisted of performing a fourteen-foot diameter aluminum alloy circumferential demonstration weld using typical fusion weld tooling. To accomplish the demonstration weld, weld and tack weld development were performed and fourteen-foot diameter rings were fabricated. Weld development consisted of weld pin tool selection and the generation of a process map and envelope. Tack weld development evaluated gas tungsten arc welding and friction stir welding for tack welding rings together for circumferential welding. As a result of the study, a successful circumferential demonstration weld was produced leading

  15. Pt/C催化邻硝基氯苯加氢反应的动力学研究%Kinetics of Ortho-nitrochlorobenzene Hydrogenation on Platinum/Carbon Catalyst

    Institute of Scientific and Technical Information of China (English)

    蒋成君; 尹红; 陈志荣

    2004-01-01

    The kinetics of catalytic hydrogenation of ortho-nitrochlorobenzene to 2,2′-dichloroazoxybenzene on platinum/carbon catalyst is investigated in a slurry reactor with the temperature range of 313-343 K, and orthochloroaniline is formed as a byproduct. Models based on Rideal-Eley and Langmuir-Hinshelwood mechanism have been proposed based on the rate data and the kinetic regime. The former model can be used to fit the experimental data better. Reaction controlling steps are physical adsorption of hydrogen and adsorbed ortho-nitrochlorobenzene reacted on the surface of catalyst.

  16. Study of gold-platinum and platinum-gold surface modification and its influence on hydrogen evolution and oxygen reduction

    Directory of Open Access Journals (Sweden)

    BRANIMIR N. GRGUR

    2005-02-01

    Full Text Available Surface modification of the electrodes was conducted from sulfuric acid solutions containing the corresponding metal–chloride complexes using cyclic voltammetry. Comparing the charges of the hydrogen underpotential deposition region, and the corresponding oxide reduction regions, it is concluded that a platinum overlayer on gold forms 3D islands, while gold on platinum forms 2D islands. Foreign metals present in an amount of up to one monolayer exert an influence on the change in reaction rate with respect to both hydrogen evolution (HER and oxygen reduction (ORR reactions. Aplatinum overlayer on a gold substrate increases the activity forHER and for ORR, compared with pure gold. These results can be understood in terms of a simple model, in which the change in the H and OH binding energies are directly proportional to the shift of the d-bond center of the overlayer. On the contrary, a gold layer on platinum slightly decreases the activity for both reactions compared with pure platinum.

  17. Optimizing treatment of the partially platinum-sensitive ovarian cancer patient.

    Science.gov (United States)

    Colombo, Nicoletta

    2013-12-01

    Ovarian cancer is the leading cause of gynecological cancer deaths worldwide. Despite primary treatment with platinum-containing regimens, the majority of women will experience recurrent disease and subsequent death. Recurrent ovarian cancer remains a challenge for successful management, and the choice of second-line chemotherapy is complex due to the range of different factors that need to be considered. One of the main considerations is the platinum-free interval and, specifically, the optimal treatment for patients who are partially platinum-sensitive (platinum-free interval: 6-12 months). Data from the large, multicenter, randomized OVA-301 study have shown that combined trabectedin-pegylated liposomal doxorubicin (PLD) significantly prolonged median overall survival compared with PLD alone (p = 0.0027) in 214 patients with partially platinum-sensitive advanced relapsed ovarian cancer. Furthermore, in OVA-301 patients with partially platinum-sensitive disease who received platinum therapy immediately after disease progression (n = 94), final median overall survival was improved by 9 months (p = 0.0153) in trabectedin-PLD patients compared with PLD alone. In addition to demonstrating a survival advantage, trabectedin-PLD may also allow the treatment of patients having not yet recovered from previous platinum toxicity. In summary, the data suggest the use of combined trabectedin-PLD as a second-line treatment option in patients with partially platinum-sensitive recurrent ovarian cancer, followed by a third-line platinum-containing regimen.

  18. Application of liposomal technologies for delivery of platinum analogs in oncology

    Directory of Open Access Journals (Sweden)

    Liu D

    2013-08-01

    Full Text Available Demin Liu1, Chunbai He1, Andrew Z Wang2, Wenbin Lin1 1Department of Chemistry, University of Chicago, Chicago, IL, USA; 2Laboratory of Nano- and Translational Medicine, Department of Radiation Oncology, and Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC, USA Abstract: Platinum-based chemotherapy, such as cisplatin, oxaliplatin, and carboplatin, is one of the most widely utilized classes of cancer therapeutics. While highly effective, the clinical applications of platinum-based drugs are limited by their toxicity profiles as well as suboptimal pharmacokinetic properties. Therefore, one of the key research areas in oncology has been to develop novel platinum analog drugs and engineer new platinum drug formulations to improve the therapeutic ratio further. Such efforts have led to the development of platinum analogs including nedaplatin, heptaplatin, and lobaplatin. Moreover, reformulating platinum drugs using liposomes has resulted in the development of L-NDPP (Aroplatin™, SPI-77, Lipoplatin™, Lipoxal™, and LiPlaCis®. Liposomes possess several attractive biological activities, including biocompatibility, high drug loading, and improved pharmacokinetics, that are well suited for platinum drug delivery. In this review, we discuss the various platinum drugs and their delivery using liposome-based drug delivery vehicles. We compare and contrast the different liposome platforms as well as speculate on the future of platinum drug delivery research. Keywords: liposome, platinum analog, drug delivery, cancer

  19. Monoclonal antibodies to intermediate filament proteins of human cells: unique and cross-reacting antibodies.

    Science.gov (United States)

    Gown, A M; Vogel, A M

    1982-11-01

    Monoclonal antibodies were generated against the intermediate filament proteins of different human cells. The reactivity of these antibodies with the different classes of intermediate filament proteins was determined by indirect immunofluorescence on cultured cells, immunologic indentification on SDS polyacrylamide gels ("wester blot" experiments), and immunoperoxidase assays on intact tissues. The following four antibodies are described: (a) an antivimentin antibody generated against human fibroblast cytoskeleton; (b), (c) two antibodies that recognize a 54-kdalton protein in human hepatocellular carcinoma cells; and (d) an antikeratin antibody made to stratum corneum that recognizes proteins of molecular weight 66 kdaltons and 57 kdaltons. The antivimentin antibody reacts with vimentin (58 kdaltons), glial fibrillary acidic protein (GFAP), and keratins from stratum corneum, but does not recognize hepatoma intermediate filaments. In immunofluorescence assays, the antibody reacts with mesenchymal cells and cultured epithelial cells that express vimentin. This antibody decorates the media of blood vessels in tissue sections. One antihepatoma filament antibody reacts only with the 54 kdalton protein of these cells and, in immunofluorescence and immunoperoxidase assays, only recognizes epithelial cells. It reacts with almost all nonsquamous epithelium. The other antihepatoma filament antibody is much less selective, reacting with vimentin, GFAP, and keratin from stratum corneum. This antibody decorates intermediate filaments of both mesenchymal and epithelial cells. The antikeratin antibody recognizes 66-kdalton and 57-kdalton proteins in extracts of stratum corneum and also identifies proteins of similar molecular weights in all cells tested. However, by immunofluorescence, this antibody decorates only the intermediate filaments of epidermoid carcinoma cells. When assayed on tissue sections, the antibody reacts with squamous epithelium and some, but not all

  20. PHASE Ⅱ STUDY OF GEMCITABINE COMBINED WITH PLATINUM CHEMOTHERAPY FOR RECURRENT EPITHELIAL OVARIAN CANCER

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To evaluate the anti-tumor effect and toxicity of gemcitabine combined with platinum chemotherapy on recurrent epithelial ovarian cancer.Methods Phase Ⅱ study of gemcitabine combined with platinum chemotherapy was carried out in 22 patients with recurrent epithelial ovarian cancer. Median age of patients was 50. 5 years old. Seven patients were platinum-sensitive and 15 patients were platinum-resistant or -refractor. All patients received gemcitabine combined with carboplatin or oxaliplatin chemotherapy. Patients' response rate (RR) and toxicity of gemcitabine combined with platinum chemotherapy were evaluated.Results A total of 98 gemcitabine-based chemotherapy cycles were performed. Total RR was 36.4%, RR of platinum-sensitive patients was 4/7 and platinum-resistant and -refractory patients was 4/15. The estimated median survival time was 10. 0 months (95% CI: 7.0-13.0) after initiation of gemcitabine combined with platinum chemotherapy.There was no significant difference in survival time between platinum-resistant/refractory group and platinum-sensitive group (P = 0. 061 ). Side effects of gemcitabine combined with platinum chemotherapy were observed in 81.8 % of patients. Grade Ⅱ/Ⅲ anemia (54.5%) and grade Ⅲ/Ⅳ neutropenia (54.5%) were most common toxicities. Ten (45.5%) patients had to delay their chemotherapy cycles or reduce the dose of chemotherapeutic drugs because of the severe side effects. Fourteen (63.6%) patients received granulocyte colony-stimulating factor to relieve neutropenia,and 8 (36. 4% ) patients received component blood transfusion to treat anemia or thrombocytopenia. There was no treatment-associated death.Conclusion Gemcitabine combined with platinum chemotherapy appears to be an effective and well-tolerant treatment for recurrent epithelial ovarian cancer, including platinum-resistant or -refractory diseases.

  1. Numerical simulation of reacting and non-reacting flow in a combustion chamber; Numerisk simulering av reagerande och icke-reagerande stroemning i en braennkammare

    Energy Technology Data Exchange (ETDEWEB)

    Borg, A.; Revstedt, J.

    1996-04-01

    The purpose of this work has been to do a preliminary study of how well numerical calculations with different turbulence models can predict the flow and temperature fields of a strongly swirling and combusting flow in an experimental combustion chamber and to see which parameters in the mathematical model are the most important. The combustion chamber on which we have done the calculations is called Validation Rig II and was designed by Volvo Aero Corporation. The main part of the study has been carried out on a non-reacting flow but some work has also been done on reacting flow. In most cases it has not been meaningful to compare the calculations with the measurements because they differ quite a lot from each other. For the non-reacting case the following investigations have been made: * How the solution differs for different turbulence models, * The solutions sensitivity to inlet boundary conditions, * How different types of leakage disturb the flow, and * The difference in results between two different CFD-codes, the commercial code CFDS-Flow3D and a code developed at the department of fluid mechanics. For the reacting cases we have studied the influence of: * one or two reaction steps, * the effects of a change in reaction rate, * the influence of thermal radiation, and * the effects of changing the boundary conditions for temperature on the walls. The results from these calculations show that the inlet turbulence intensity has very little effect on the values of the turbulent quantities as well as the velocity profiles at the outlet. Changing the turbulence model or the outlet boundary conditions gives some change in velocity profiles at the outlet but only marginal effects on the swirl number. 21 refs, 54 figs, 19 tabs

  2. STABILITY OF THE NEW ANTICANCER PLATINUM ANALOG 1,2-DIAMINOMETHYL-CYCLOBUTANE-PLATINUM(II)-LACTATE (LOBAPLATIN-D19466) IN INTRAVENOUS SOLUTIONS

    NARCIS (Netherlands)

    GUCHELAAR, HJ; UGES, DRA; AULENBACHER, P; DEVRIES, EGE; MULDER, NH

    The chemical stability of the new anticancer platinum analogue 1,2-diaminomethyl-cyclobutane-platinum(II)-lactate (D19466) in infusion media was studied in an accelerated stability testing experiment with a selective HPLC-UV method. Variables were time, temperature, light, concentration, and

  3. Comparison of Intracellular Stress Response of NCI-H526 Small Cell Lung Cancer (SCLC) Cells to Platinum(II) Cisplatin and Platinum(IV) Oxoplatin

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, Gerhard [Ludwig Boltzmann Cluster of Translational Oncology, A-1090 Vienna (Austria)

    2014-07-08

    In attempts to develop an orally applicable platinum-based drug, platinum(IV) drugs which exhibit higher in vivo stability compared to the platinum(II) drug cisplatin were formulated. The first such chemotherapeutic agent, namely satraplatin, failed to receive approval. In the present work, we checked the initial cellular stress response of the chemosensitive NCI-H526 small cell lung cancer (SCLC) cells by determination of the relative phosphorylation of 46 specific phosphorylation sites of 38 selected proteins in a six hours response to cisplatin (platinum(II)) or oxoplatin (platinum(IV)), respectively. Oxoplatin is considered as prodrug of cisplatin, although several findings point to differences in intracellular effects. Cisplatin induced hyperphosphorylation of p38α MAPK and AMPKα1, whereas oxoplatin treatment resulted in increased phosphorylation of a large number of signaling proteins involved in stress response/drug resistance, including JNK, GSK-3α, AMPKα1, src kinases, STATs, CHK-2 and especially focal adhesion kinase (FAK). Cisplatin exerts markedly higher cytotoxicity upon four hours short-term exposure in comparison to oxoplatin and, correspondingly, the extended initial stress response to the platinum(IV) drug oxoplatin thus is expected to increase clinical drug resistance. Induction of a substantial stress response to any prodrug of a platinum-based compound may likewise limit the effectivity of its active metabolite(s), such contributing to the failure of selected derivatized platinum complexes.

  4. Comparison of Intracellular Stress Response of NCI-H526 Small Cell Lung Cancer (SCLC Cells to Platinum(II Cisplatin and Platinum(IV Oxoplatin

    Directory of Open Access Journals (Sweden)

    Gerhard Hamilton

    2014-07-01

    Full Text Available In attempts to develop an orally applicable platinum-based drug, platinum(IV drugs which exhibit higher in vivo stability compared to the platinum(II drug cisplatin were formulated. The first such chemotherapeutic agent, namely satraplatin, failed to receive approval. In the present work, we checked the initial cellular stress response of the chemosensitive NCI-H526 small cell lung cancer (SCLC cells by determination of the relative phosphorylation of 46 specific phosphorylation sites of 38 selected proteins in a six hours response to cisplatin (platinum(II or oxoplatin (platinum(IV, respectively. Oxoplatin is considered as prodrug of cisplatin, although several findings point to differences in intracellular effects. Cisplatin induced hyperphosphorylation of p38α MAPK and AMPKα1, whereas oxoplatin treatment resulted in increased phosphorylation of a large number of signaling proteins involved in stress response/drug resistance, including JNK, GSK-3α, AMPKα1, src kinases, STATs, CHK-2 and especially focal adhesion kinase (FAK. Cisplatin exerts markedly higher cytotoxicity upon four hours short-term exposure in comparison to oxoplatin and, correspondingly, the extended initial stress response to the platinum(IV drug oxoplatin thus is expected to increase clinical drug resistance. Induction of a substantial stress response to any prodrug of a platinum-based compound may likewise limit the effectivity of its active metabolite(s, such contributing to the failure of selected derivatized platinum complexes.

  5. Platinum thickness dependence of the inverse spin-Hall voltage from spin pumping in a hybrid yttrium iron garnet/platinum system

    NARCIS (Netherlands)

    Castel, V.; Vlietstra, N.; Ben Youssef, J.; van Wees, B. J.

    2012-01-01

    We show the experimental observation of the platinum thickness dependence in a hybrid yttrium iron garnet/platinum system of the inverse spin-Hall effect from spin pumping, over a large frequency range and for different radio-frequency powers. From the measurement of the voltage at the resonant cond

  6. Study of Transport and Micro-structural properties of Magnesium Di-Boride Strand under react and bend mode and bend and react mode

    Science.gov (United States)

    Kundu, Ananya; Das, Subrat Kumar; Bano, Anees; Pradhan, Subrata

    2017-04-01

    I-V characterization of commercial multi-filamentary Magnesium Di-Boride (MgB2) wire of diameter 0.83 mm were studied in Cryocooler at self-field I-V characterization system under both react and bend mode and bend and react mode for a range of temperature 6 K - 25 K. This study is of practical technical relevance where the heat treatment of the superconducting wire makes the wire less flexible for winding in magnet and in other applications. In the present work the bending diameter was varied from 40 mm to 20 mm and for each case critical current (Ic) of the strand is measured for above range of temperature. A customized sample holder is fabricated and thermally anchored with the 2nd cold stage of Cryocooler. It is observed from the measurement that the strand is more susceptible to degradation for react and bend cases. The transport measurement of the strand was accompanied by SEM analyses of bend samples. Also the tensile strength of the raw strands and the heat treated strands were carried out at room temperature in Universal Testing Machine (UTM) to have an estimate about the limiting winding tension value during magnet fabrication.

  7. Recent Advances in Platinum (IV) Complex-Based Delivery Systems to Improve Platinum (II) Anticancer Therapy.

    Science.gov (United States)

    Han, Xiaopeng; Sun, Jin; Wang, Yongjun; He, Zhonggui

    2015-11-01

    Cisplatin and its platinum (Pt) (II) derivatives play a key role in the fight against various human cancers such as testicular, ovarian, head and neck, lung tumors. However, their application in clinic is limited due to dose- dependent toxicities and acquired drug resistances, which have prompted extensive research effort toward the development of more effective Pt (II) delivery strategies. The synthesis of Pt (IV) complex is one such an area of intense research fields, which involves their in vivo conversion into active Pt (II) molecules under the reducing intracellular environment, and has demonstrated encouraging preclinical and clinical outcomes. Compared with Pt (II) complexes, Pt (IV) complexes not only exhibit an increased stability and reduced side effects, but also facilitate the intravenous-to-oral switch in cancer chemotherapy. The overview briefly analyzes statuses of Pt (II) complex that are in clinical use, and then focuses on the development of Pt (IV) complexes. Finally, recent advances in Pt (IV) complexes in combination with nanocarriers are highlighted, addressing the shortcomings of Pt (IV) complexes, such as their instability in blood and irreversibly binding to plasma proteins and nonspecific distribution, and taking advantage of passive and active targeting effect to improve Pt (II) anticancer therapy. © 2015 Wiley Periodicals, Inc.

  8. TP53 status and taxane-platinum versus platinum-based therapy in ovarian cancer patients: A non-randomized retrospective study

    Directory of Open Access Journals (Sweden)

    Markowska Janina

    2008-01-01

    Full Text Available Abstract Background Taxane-platinum therapy (TP has replaced platinum-based therapy (PC or PAC, DNA damaging chemotherapy in the postoperative treatment of ovarian cancer patients; however, it is not always effective. TP53 protein plays a differential role in response to DNA-damaging agents and taxanes. We sought to define profiles of patients who benefit the most from TP and also of those who can be treated with PC. Methods We compared the effectiveness of PC/PAC (n = 253 and TP (n = 199 with respect to tumor TP53 accumulation in ovarian cancer patients with FIGO stage IIB-IV disease; this was a non-randomized retrospective study. Immunohistochemical analysis was performed on 452 archival tumors; univariate and multivariate analysis by the Cox's and logistic regression models was performed in all patients and in subgroups with [TP53(+] and without TP53 accumulation [TP53(-]. Results The advantage of taxane-platinum therapy over platinum-based therapy was seen in the TP53(+, and not in the TP53(- group. In the TP53(+ group taxane-platinum therapy enhanced the probability of complete remission (p = .018, platinum sensitivity (p = .014, platinum highly sensitive response (p = .038 and longer survival (OS, p = .008. Poor tumor differentiation diminished the advantage from taxane-platinum therapy in the TP53(+ group. In the TP53(- group PC/PAC was at least equally efficient as taxane-platinum therapy and it enhanced the chance of platinum highly sensitive response (p = .010. However, in the TP53(- group taxane-platinum therapy possibly diminished the risk of death in patients over 53 yrs (p = .077. Among factors that positively interacted with taxane-platinum therapy in some analyses were endometrioid and clear cell type, FIGO III stage, bulky residual tumor, more advanced age of patient and moderate tumor differentiation. Conclusion Our results suggest that taxane-platinum therapy is particularly justified in patients with TP53(+ tumors or older

  9. An experimental and numerical study of confined non-reacting and reacting turbulent jets to facilitate homogeneous combustion in industrial furnaces

    Science.gov (United States)

    Lee, Insu

    Confined non-reacting turbulent jets are ideal for recirculating the hot flue gas back into the furnace from an external exhaust duct. Such jets are also used inside the furnace to internally entrain and recirculate the hot flue gas to preheat and dilute the reactants. Both internal and external implementation of confined turbulent jets increase the furnace thermal efficiency. For external implementation, depending on the circumstances, the exhaust gas flow may be co- or counter-flow relative to the jet flow. Inside the furnaces, fuel and air jets are injected separately. To create a condition which can facilitate near homogeneous combustion, these jets have to first mix with the burned gas inside the furnace and simultaneously being heated and diluted prior to combustion. Clearly, the combustion pattern and emissions from reacting confined turbulent jets are affected by jet interactions, mixing and entrainment of hot flue gas. In this work, the flow and mixing characteristics of a non-reacting and reacting confined turbulent jet are investigated experimentally and numerically. This work consists of two parts: (i) A study of flow and mixing characteristics of non-reacting confined turbulent jets with co- or counter-flowing exhaust/flue gas. Here the axial and radial distributions of temperature, velocity and NO concentration (used as a tracer gas) were measured. FLUENT was used to numerically simulate the experimental results. This work provides the basic understanding of the flow and mixing characteristics of confined turbulent jets and develops some design considerations for recirculating flue gas back into the furnace as expressed by the recirculation zone and the stagnation locations. (ii) Numerical calculations of near homogeneous combustion are performed for the existing furnace. The exact geometry of the furnace in the lab is used and the real dimensional boundary conditions are considered. The parameters such as air nozzle diameter (dair), fuel nozzle

  10. Technical note: Can the sulfur hexafluoride tracer gas technique be used to accurately measure enteric methane production from ruminally cannulated cattle?

    Science.gov (United States)

    Beauchemin, K A; Coates, T; Farr, B; McGinn, S M

    2012-08-01

    An experiment was conducted to determine whether using ruminally cannulated cattle affects the estimate of enteric methane (CH(4)) emissions when using the sulfur hexafluoride (SF(6)) tracer technique with samples taken from a head canister. Eleven beef cattle were surgically fitted with several types of ruminal cannula (2C, 3C, 3C+washer, 9C; Bar Diamond, Parma, ID). The 2C and 3C models (outer and inner flanges with opposite curvature) had medium to high leakage, whereas the 9C models (outer and inner flanges with the same curvature) provided minimum to moderate leakage of gas. A total of 48 cow-day measurements were conducted. For each animal, a permeation tube containing sulfur hexafluoride (SF(6)) was placed in the rumen, and a sample of air from around the nose and mouth was drawn through tubing into an evacuated canister (head canister). A second sample of air was collected from outside the rumen near the cannula into another canister (cannula canister). Background concentrations were also monitored. The methane (CH(4)) emission was estimated from the daily CH(4) and SF(6) concentrations in the head canister (uncorrected). The permeation SF(6) release rate was then partitioned based on the proportion of the SF(6) concentration measured in the head vs. the cannula canister. The CH(4) emissions at each site were calculated using the two release rates and the two CH(4):SF(6) concentration ratios. The head and cannula emissions were summed to obtain the total emission (corrected). The difference (corrected - uncorrected) in CH4 emission was attributed to the differences in CH(4):SF(6) ratio at the 2 exit locations. The proportions of CH(4) and SF(6) recovered at the head were greater (P 0.05; 2C, 6% and 4%; 3C, 17% and 15%; 3C+washer, 19% and 14%). Uncorrected CH(4) emissions were ± 10% of corrected emissions for 53% of the cow-day measurements. Only when more than 80% of the SF(6) escaped via the rumen did the difference between the uncorrected and corrected

  11. Platinum recycling going green via induced surface potential alteration enabling fast and efficient dissolution

    Science.gov (United States)

    Hodnik, Nejc; Baldizzone, Claudio; Polymeros, George; Geiger, Simon; Grote, Jan-Philipp; Cherevko, Serhiy; Mingers, Andrea; Zeradjanin, Aleksandar; Mayrhofer, Karl J. J.

    2016-01-01

    The recycling of precious metals, for example, platinum, is an essential aspect of sustainability for the modern industry and energy sectors. However, due to its resistance to corrosion, platinum-leaching techniques rely on high reagent consumption and hazardous processes, for example, boiling aqua regia; a mixture of concentrated nitric and hydrochloric acid. Here we demonstrate that complete dissolution of metallic platinum can be achieved by induced surface potential alteration, an ‘electrode-less' process utilizing alternatively oxidative and reductive gases. This concept for platinum recycling exploits the so-called transient dissolution mechanism, triggered by a repetitive change in platinum surface oxidation state, without using any external electric current or electrodes. The effective performance in non-toxic low-concentrated acid and at room temperature is a strong benefit of this approach, potentially rendering recycling of industrial catalysts, including but not limited to platinum-based systems, more sustainable. PMID:27767178

  12. Platinum recycling going green via induced surface potential alteration enabling fast and efficient dissolution

    Science.gov (United States)

    Hodnik, Nejc; Baldizzone, Claudio; Polymeros, George; Geiger, Simon; Grote, Jan-Philipp; Cherevko, Serhiy; Mingers, Andrea; Zeradjanin, Aleksandar; Mayrhofer, Karl J. J.

    2016-10-01

    The recycling of precious metals, for example, platinum, is an essential aspect of sustainability for the modern industry and energy sectors. However, due to its resistance to corrosion, platinum-leaching techniques rely on high reagent consumption and hazardous processes, for example, boiling aqua regia; a mixture of concentrated nitric and hydrochloric acid. Here we demonstrate that complete dissolution of metallic platinum can be achieved by induced surface potential alteration, an `electrode-less' process utilizing alternatively oxidative and reductive gases. This concept for platinum recycling exploits the so-called transient dissolution mechanism, triggered by a repetitive change in platinum surface oxidation state, without using any external electric current or electrodes. The effective performance in non-toxic low-concentrated acid and at room temperature is a strong benefit of this approach, potentially rendering recycling of industrial catalysts, including but not limited to platinum-based systems, more sustainable.

  13. Tuning the activity of platinum(IV) anticancer complexes through asymmetric acylation.

    Science.gov (United States)

    Chin, Chee Fei; Tian, Quan; Setyawati, Magdiel Inggrid; Fang, Wanru; Tan, Emelyn Sue Qing; Leong, David Tai; Ang, Wee Han

    2012-09-13

    Platinum(II) anticancer drug cisplatin is one of the most important chemotherapeutic agents in clinical use but is limited by its high toxicity and severe side effects. Platinum(IV) anticancer prodrugs can overcome these limitations by resisting premature aquation and binding to essential plasma proteins. Structure-activity relationship studies revealed a link between the efficacy of platinum(IV) complexes with the nature of their axial ligands, which can be modified to enhance the properties of the prodrug. The existing paradigm of employing platinum(IV) complexes with symmetrical axial carboxylate ligands does not fully exploit their vast potential. A new approach was conceived to control properties of platinum(IV) prodrugs using contrasting axial ligands via sequential acylation. We report a novel class of asymmetric platinum(IV) carboxylates based on the cisplatin template containing both hydrophilic and lipophilic ligands on the same scaffold designed to improve their aqueous properties and enhance their efficacy against cancer cells in vitro.

  14. Platinum overlayers on Co(0001) and Ni(111): numerical simulation of surface alloying

    Science.gov (United States)

    Légaré, P.; Cabeza, G. F.; Castellani, N. J.

    1999-11-01

    The surface alloying of one and two monolayers (ML) of platinum deposited on Ni(111) and Co(0001) were studied by means of the ECT-BFS method. The 1 ML deposit appears to be very stable on both substrates. Platinum can diffuse at high temperature only, the large activation barrier being represented by the first substrate layer. On the contrary, the stability of the 2 ML deposit is poor so that alloying is easily obtained. In both cases, the platinum diffusion produces metastable states. The lowest-energy states exhibit a propensity for platinum dilution in a limited region below the surface. The initial platinum thickness determines not only the features of the alloyed region, but also the surface concentration. The surface alloys have features qualitatively similar to those reported for the (111) surface of bulk Pt-Ni and Pt-Co alloys: a platinum-rich surface and oscillating concentration profiles.

  15. Morphology of Platinum Nanowire Array Electrodeposited Within Anodic Aluminium Oxide Template Characterized by Atomic Force Microscopy

    Institute of Scientific and Technical Information of China (English)

    孔令斌; 陆梅; 李梦轲; 郭新勇; 力虎林

    2003-01-01

    Uniform platinum nanowires were synthesized by electrodepositing the platinum under a very low altering current frequency (20Hz) and increasing voltage (5-15 V) in the pores of anodic aluminium oxide (AAO) template.Atomic force microscopy observation indicates that the template membranes we obtained have hexagonally closepacked nanochannels. The platinum nanowires have highly ordered arrays after partially dissolving the aluminium oxide membrane. With the increasing dissolving time, the platinum nanowire array collapsed. A concave topography of the aluminium substrate was observed after the aluminium oxide membrane was dissolved completely and the platinum nanowires were released from the template. Platinum nanowires were also characterized by transmission electron microscopy and the phase structure of the Al/AAO/Pt composite was proven by x-ray diffraction.

  16. Platinum Migration at the Pt/YSZ Interface

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Jacobsen, Torben

    2006-01-01

    by potential sweep, step and impedance techniques. As expected, inductive behaviour and activation during step polarization is confirmed, but furthermore, a very accentuated noise pattern is seen during cathodic step polarization. Investigation of the YSZ and Pt surfaces afterwards reveals the growth......Electrode activation, inductive hysteresis and non-linearity are well known phenomena on Pt-YSZ electrodes, and recently also regular fluctuation patterns have been reported. The oxygen electrode on YSZ surfaces is studied at Pt micro-electrodes prepared by electrochemical etching of platinum wire...... of dendrite like Pt structures from the TPB. The formation of these may explain the observed noise and contribute to the explanation of the activation mechanism taking place at the platinum-YSZ interface....

  17. Nanostructured gold and platinum electrodes on silicon structures for biosensing

    Science.gov (United States)

    Ogurtsov, V. I.; Sheehan, M. M.

    2005-01-01

    Gold and platinum metal electrodes on Si/SiO2 having undergone anisotropic potassium hydroxide (KOH) etch treatment are considered. This treatment etches at different rates and directions in the material resulting in creation of numerous pyramid shaped holes in the silicon substrate. This surface is used to make metal electrodes with increased electrode efficiency. The electrodes can serve as the sensors or as the sensor substrates (for surface polymer modification) and because both gold and platinum are inert they have applications for food safety biosensing. Wine, an economically significant food product, was chosen as a matrix, and impedance spectroscopy (EIS) was selected as a method of investigation of electrode behaviour. Based on results of EIS, different complexity equivalent circuits were determined by applying fitting mean square root optimisation of sensor complex impedance measurements.

  18. Hollow platinum alloy tailored counter electrodes for photovoltaic applications

    Science.gov (United States)

    Li, Pinjiang; Zhang, Yange; Fa, Wenjun; Yang, Xiaogang; Wang, Liang

    2017-08-01

    Without sacrifice of photovoltaic performances, low-platinum alloy counter electrodes (CEs) are promising in bringing down the fabrication cost of dye-sensitized solar cells (DSSCs). We present here the realization of ZnO nanostructure assisted hollow platinum-nickel (PtNi) alloy microstructure CEs with a simple hydrothermal methods and maximization of electrocatalytic behaviors by tuning Zn precursors. The maximal power conversion efficiency is up to 8.74% for the liquid-junction dye-sensitized solar cells with alloyed PtNi0.41 electrode, yielding a 37.6% cell efficiency enhancement in comparison with pristine solar cell from planar Pt electrode. Moreover, the dissolution-resistant and charge-transfer abilities toward I-/I3- redox electrolyte have also been markedly enhanced due to competitive dissolution reactions and alloying effects.

  19. Immune response of sheep to Haemonchus contortus: serum antibodies against cross reacting antigens between parasites.

    Science.gov (United States)

    Charley, J; Bourdieu, C; Luffau, G; Pery, P

    1981-01-01

    Normal and H. contortus infected sera were studied by ELISA technique against different stages of the parasites. In all cases antibody activity was detected. This activity in serum is partially eliminated after absorption with an adult worm extract of N brasiliensis. N. brasiliensis and H. contortus antigens were analysed by TCIEP with a rabbit anti-N. brasiliensis serum to examine shared antigens of H. contortus. A minimum of seven cross reacting antigens were detected. H. contortus adult worm extract was absorbed by the rabbit anti-N. brasiliensis serum. After absorption all cross reacting antigens were removed but at least one antigen reacting with a rabbit serum anti-H. Contortus is maintained. When this antigen is tested in elisa technique only a weak antibody activity is found in normal serum.

  20. Process to separate alkali metal salts from alkali metal reacted hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, John Howard; Alvare, Javier; Larsen, Dennis; Killpack, Jeff

    2017-06-27

    A process to facilitate gravimetric separation of alkali metal salts, such as alkali metal sulfides and polysulfides, from alkali metal reacted hydrocarbons. The disclosed process is part of a method of upgrading a hydrocarbon feedstock by removing heteroatoms and/or one or more heavy metals from the hydrocarbon feedstock composition. This method reacts the oil feedstock with an alkali metal and an upgradant hydrocarbon. The alkali metal reacts with a portion of the heteroatoms and/or one or more heavy metals to form an inorganic phase containing alkali metal salts and reduced heavy metals, and an upgraded hydrocarbon feedstock. The inorganic phase may be gravimetrically separated from the upgraded hydrocarbon feedstock after mixing at a temperature between about 350.degree. C. to 400.degree. C. for a time period between about 15 minutes and 2 hours.

  1. The extractive metallurgy of south africa's platinum ores

    Science.gov (United States)

    Cramer, Larry A.

    2001-10-01

    The extraction technology for platinum-group metals (PGMs) has changed dramatically in the last 80 years, and the changes are likely to continue for years to come. This article will review advances in PGM extraction, including developments in semi-autogenous and fully autogenous milling; flotation equipment applications for treating high-chrome ores; increases in power densities for future smelting furnaces, and new methods for meeting rising environmental standards.

  2. Phase I trials of WR-2721 and cis-platinum

    Energy Technology Data Exchange (ETDEWEB)

    Glover, D.; Glick, J.H.; Weiler, C.; Yuhas, J.; Kligerman, M.M.

    1984-09-01

    WR-2721 is a sulfhydryl compound which in the animal model improves renal tolerance to cis-platinum (DDP) by factors of 1.3 to 1.7. Phase I trials were initiated to establish the toxicity and dose modification factor when WR-2721 was given prior to escalating doses of DDP. Nineteen patients received 27 courses of WR-2721 (450-910 mg/m/sup 2/) 20 minutes prior to DDP (50-120 mg/m/sup 2/). Mild, transient nephrotoxicity was observed in only 2 of 15 courses of DDP 80-100 mg/m/sup 2/ when WR-2721 was given prior to DDP. Although 5 of 9 patients treated with WR-2721 prior to 120 mg/m/sup 2/ of DDP developed transient nephrotoxicity, their serum creatinines returned to normal baseline values within 1 to 2 weeks. Thirty-four courses of WR-2721 (740 mg/m/sup 2/) prior to DDP 120-150 mg/m/sup 2/ with mannitol diuresis were administered. Biweekly serum creatinine and monthly creatinine clearances have remained normal in all patients treated with 120 mg/m/sup 2/ of platinum and WR-2721. Four of 10 patients treated with 150 mg/m/sup 2/ of cis-platinum experienced transient nephrotoxicity 5-7 days after treatment. Mild ototoxicity was noted in 4 patients following 150 mg/m/sup 2/ of DDP. WR-2721 does not appear to protect against the antitumor efficacy of DDP. Compared to retrospective series, our data suggest that WR-2721 may provide some protection against platinum-induced nephrotoxicity, but the dose modification factors remain to be established.

  3. Experimental Studies on Thermal and Electrical Properties of Platinum Nanofilms

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xing; ZHANG Qing-Guang; CAO Bing-Yang; FUJII Motoo; TAKAHASHI Koji; IKUTA Tatsuya

    2006-01-01

    @@ We experimentally studied the in-plane thermal and electrical properties of a suspended platinum nanofilm in thickness of 15 nm. The measured results show that the in-plane thermal conductivity, the electrical conductivity and the resistance-temperature coefficient of the studied nanofilm are much less than those of the bulk material,while the Lorenz number is greater than the bulk value.

  4. Stabilization of 200-atom platinum nanoparticles by organosilane fragments

    KAUST Repository

    Pelzer, Katrin

    2011-04-19

    Three\\'s a charm: Platinum nanoparticles of 2 nm diameter and containing approximately 200 atoms covered with n-octylsilyl groups (see picture, right; Pt blue, Si red, C gray, H turquoise) form when [Pt(dba)2] (dba=dibenzylideneacetone) decomposes in the presence of n-octylsilane. The particles adopt a cuboctahedral structure with an edge length of three atoms. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Treatment of pulmonary arteriovenous malformation using platinum coils: case report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Man Deuk; Kim, Jeung Sook; Lim, Chang Young [College of Medicine, Pochon CHA University, Pochon (China)

    2005-07-15

    Pulmonary arteriovenous malformation (PAVM) is an abnormal direct communication between the pulmonary arteries and veins without any capillary network. The patients may be completely asymptomatic or may they develop serious complications including hemoptysis and brain abscess. We present here a case of incidentally found PAVM in a 33-year-old male who underwent embolization using platinum coils. Coil embolization is a safe, highly effective procedure that should be considered more often for the treatment of PAVM.

  6. Platinum(II) complexes as spectroscopic probes for biomolecules

    Energy Technology Data Exchange (ETDEWEB)

    Ratilla, E.

    1990-09-21

    The use of platinum(II) complexes as tags and probes for biomolecules is indeed advantageous for their reactivities can be selective for certain purposes through an interplay of mild reaction conditions and of the ligands bound to the platinum. The use of {sup 195}Pt NMR as a method of detecting platinum and its interactions with biomolecules was carried out with the simplest model of platinum(II) tagging to proteins. Variable-temperature {sup 195}Pt NMR spectroscopy proved useful in studying the stereodynamics of complex thioethers like methionine. The complex, Pt(trpy)Cl{sup +}, with its chromophore has a greater potential for probing proteins. It is a noninvasive and selective tag for histidine and cysteine residues on the surface of cytochrome c at pH 5. The protein derivatives obtained are separable, and the tags are easily quantitated and differentiated through the metal-to-ligand charge transfer bands which are sensitive to the environment of the tag. Increasing the pH to 7.0 led to the modification by Pt(trpy)Cl{sup +}of Arg 91 in cytochrome c. Further studies with guanidine-containing ligands as models for arginine modification by Pt(trpy)Cl{sup +} showed that guanidine can act as a terminal ligand and as a bridging ligand. Owing to the potential utility of Pt(trpy)L{sup n+} as electron dense probes of nucleic acid structure, interactions of this bis-Pt(trpy){sup 2+} complex with nucleic acids was evaluated. Indeed, the complex interacts non-covalently with nucleic acids. Its interactions with DNA are not exactly the same as those of its precedents. Most striking is its ability to form highly immobile bands of DNA upon gel electrophoresis. 232 refs.

  7. Modification of platinum surfaces by spontaneous deposition: Methanol oxidation electrocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, J.P.; Gualtieri, B.; Runga, N.; Teliz, E.; Zinola, C.F. [Fundamental Electrochemistry Laboratory, School of Sciences, Universidad de la Republica, Igua Street No. 4225, CP 11400, Montevideo (Uruguay)

    2008-12-15

    The presence of a second metal on platinum surfaces affects the performance of methanol oxidation. However, most of the electrocatalytic reactions are studied by using electrochemically deposited platinum alloys, but in the case of spontaneous deposition the situation is not so clear since the surface distribution, stability and morphology are usually not well documented. The formation of surface decorated samples on mono- and poly-crystalline platinum is followed by electrochemical and spectroscopic techniques and analysis of their performance towards methanol adsorption and oxidation compared with that on pure platinum. Pt/Sn and Pt/Ru are of special interest because of their well-known performance in methanol fuel cells. Methanol oxidation on Pt(111)/Ru, Pt(111)/Sn and Pt(111) shows that ruthenium is the only one able to promote the reaction since the simultaneous dissolution of tin occurs and competes with the process of interest. The in situ infrared spectroscopy is used to compare methanol oxidation on Pt(111)/Ru and Pt(111) in acid media using p-polarized light. The formation of bridge bound carbon monoxide is inhibited in the presence of ruthenium ad-species, whereas on Pt(111) the three adsorption configurations are observed. Linear sweep polarization curves and Tafel slopes (calculated from steady state potentiostatic plots) for methanol oxidation are compared on polycrystalline surfaces modified by tin or ruthenium at different coverages. There is almost no change in the Tafel slopes due to the presence of the foreign metal except for Pt/Ru, where a 0.09 V decade{sup -1} slope was calculated below 0.55 V due to hydroxyl adsorbates on ruthenium islands. The anodic stripping of methanol residues on the three surfaces indicates a lower amount of carbon monoxide-type adsorbates on Pt/Ru, and the simultaneous tin dissolution process leading to residues oxidation on Pt/Sn electrodes. (author)

  8. Mechanistic basis for overcoming platinum resistance using copper chelating agents.

    Science.gov (United States)

    Liang, Zheng D; Long, Yan; Tsai, Wen-Bin; Fu, Siqing; Kurzrock, Razelle; Gagea-Iurascu, Mihai; Zhang, Fan; Chen, Helen H W; Hennessy, Bryan T; Mills, Gordon B; Savaraj, Niramol; Kuo, Macus Tien

    2012-11-01

    Platinum-based antitumor agents are widely used in cancer chemotherapy. Drug resistance is a major obstacle to the successful use of these agents because once drug resistance develops, other effective treatment options are limited. Recently, we conducted a clinical trial using a copper-lowering agent to overcome platinum drug resistance in ovarian cancer patients and the preliminary results are encouraging. In supporting this clinical study, using three pairs of cisplatin (cDDP)-resistant cell lines and two ovarian cancer cell lines derived from patients who had failed in platinum-based chemotherapy, we showed that cDDP resistance associated with reduced expression of the high-affinity copper transporter (hCtr1), which is also a cDDP transporter, can be preferentially resensitized by copper-lowering agents because of enhanced hCtr1 expression, as compared with their drug-sensitive counterparts. Such a preferential induction of hCtr1 expression in cDDP-resistant variants by copper chelation can be explained by the mammalian copper homeostasis regulatory mechanism. Enhanced cell-killing efficacy by a copper-lowering agent was also observed in animal xenografts bearing cDDP-resistant cells. Finally, by analyzing a public gene expression dataset, we found that ovarian cancer patients with elevated levels of hCtr1 in their tumors, but not ATP7A and ATP7B, had more favorable outcomes after platinum drug treatment than those expressing low hCtr1 levels. This study reveals the mechanistic basis for using copper chelation to overcome cDDP resistance in clinical investigations.

  9. Characterisation of carbon nanotubes decorated with platinum nanoparticles

    OpenAIRE

    M. Pawlyta; D. Łukowiec; A.D. Dobrzańska-Danikiewicz

    2012-01-01

    Purpose: In presented work results of synthesis of carbon nanotubes decorated with platinum nanoparticles by organic colloidal process as an example of direct formation of nanoparticles onto CNTs are reported.Design/methodology/approach: Powder XRD and transmission electron microscopy were used for characterisation of the morphology of composite as well as the distribution of nanocrystals on the CNTs surfaces.Findings: TEM results confirm that CNT were homogeneous and clean, without any admix...

  10. A Single Platinum Microelectrode for Identifying Soft Drink Samples

    OpenAIRE

    Lígia Bueno; Thiago R. L. C. Paixão

    2012-01-01

    Cyclic voltammograms recorded with a single platinum microelectrode were used along with a non-supervised pattern recognition, namely, Principal Component Analysis, to conduct a qualitative analysis of sixteen different brands of carbonated soft drinks (Kuat, Soda Antarctica, H2OH!, Sprite 2.0, Guarana Antarctica, Guarana Antarctica Zero, Coca-Cola, Coca-Cola Zero, Coca-Cola Plus, Pepsi, Pepsi Light, Pepsi Twist, Pepsi Twist Light, Pepsi Twist 3, Schin Cola, and Classic Dillar’s). In this ana...

  11. Determination of Platinum Metals in Carbonaceous Mineral Raw Materials by Stripping Voltammetry

    OpenAIRE

    Kolpakova, Nina Alexandrovna; Oskina, Yuliya Aleksandrovna; Dyachenko, Elena Nikolaevna; Pshenichkin, Anatoliy Yakovlevich

    2015-01-01

    The paper considers the possibility of determining platinum metals in mineral raw materials by stripping voltammetry on a graphite electrode modified by metals. Stripping voltammetry method is characterized by low determination limit, wide intervals of determined content and high sensitivity. As a result of the research the conditions for the determination of gold, platinum and palladium by stripping voltammetry have been selected. The comparison of the results of gold, palladium and platinum...

  12. Lowering the resistivity of polyacrylate ion-selective membranes by platinum nanoparticles addition.

    Science.gov (United States)

    Jaworska, Ewa; Kisiel, Anna; Maksymiuk, Krzysztof; Michalska, Agata

    2011-01-01

    The effect of platinum nanoparticles introduction into polyacrylate membranes was examined. Platinum nanoparticles were added to the membrane cocktail before photopolymerization of the poly(n-butyl acrylate) based ion-selective membranes. Thus obtained sensors were characterized with significantly lowered electrical resistance and increased stability of potential readings compared to classical poly(n-butyl acrylate) membranes. The analytical parameters of platinum nanoparticle containing membranes were well comparable with those of classical membranes.

  13. Elaboration and Properties of Nanocomposite Structures Based on Crown Modified Platinum Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    H.Perez; S.Cavaliere-jaricot; P-A.Albouy; A.Etcheberry

    2007-01-01

    1 Results This paper presents the development of platinum nanocomposites structures based on organically modified c.a.2 nm core platinum nanoparticles.The chemical modification of the 4-mercaptoaniline functionalized particles by various in coming molecules is evidenced and precisely quantified.The particles can be dissolved like molecules in various solvents depending on the features of the new crown and X-rays shows that the interparticle distance is affected by the crown modification.These platinum n...

  14. Organo-platinum complexes as antitumor agents (review).

    Science.gov (United States)

    Hill, J M; Speer, R J

    1982-01-01

    Rosenberg et al discovered in the coordination complexes of platinum a new, novel type of potential antitumor agent. Cisplatin [cis-dichlorodiammine platinum (II)4 proved active against a variety of rodent tumors and acted synergistically when combined with other chemotherapeutic agents. Initial clinical tests by Hill et al in 1971, showed cisplatin to be active against malignant lymphoma, Hodgkin's disease, and certain other malignancies. Significant nephrotoxicity, nausea, and vomiting were noted. Since then, cisplatin has been tested alone and in combination chemotherapy and has proven an efficacious anticancer agent in squamous cell carcinoma of head and neck, ovarian carcinoma, disseminated testicular cancer, and others. Its therapeutic value was acknowledged when approved in 1978 by the U.S. FDA for treatment of the latter cancer. The current clinical literature indicates clearly that the full potential of this drug has not yet been realized. Hydration and diuresis have served to mitigate much of the nephrotoxicity, while significant strides toward amelioration of the nausea and vomiting have also been achieved. Literally, thousands of chemically-related congeners have been synthesized, and many have shown marked potency against rodent tumors. Very few, however, have been evaluated clinically, vis-a-vis malonato trans(-)-1,2-diaminocyclohexane platinum(II); this appears a most promising and fertile area of future investigation.

  15. Upper eyelid platinum chain placement for treating paralytic lagophthalmos.

    Science.gov (United States)

    Bianchi, B; Ferri, A; Leporati, M; Ferrari, S; Lanfranco, D; Ferri, T; Sesenna, E

    2014-12-01

    For the definitive treatment of lagophthalmos and satisfactory rehabilitation of the affected eye, different surgical strategies have been proposed, including static or dynamic procedures. Although some of these can have good results, lid loading is now the most common technique for treating paralytic long-term lagophthalmos. Among the different types of loading, the use of a platinum chain is preferred to the use of a standard gold weight because platinum has a higher density than gold and is also more biocompatible. In this paper authors retrospectively analyzed 43 patients with regards to functional and cosmetic results. Questionnaires were also employed to assess changes and improvements in the patients' quality of life. Analysis of the excellent results achieved confirmed that platinum chain lid loading should be considered as a first-line treatment for paralytic lagophthalmos rehabilitation. It is a simple, reliable, and effective technique that significantly improves the health-related quality of life of patients. Copyright © 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  16. First platinum moderated positron beam based on neutron capture

    CERN Document Server

    Hugenschmidt, C; Repper, R; Schreckenbach, K; Sperr, P; Triftshaeuser, W

    2002-01-01

    A positron beam based on absorption of high energy prompt gamma-rays from thermal neutron capture in sup 1 sup 1 sup 3 Cd was installed at a neutron guide of the high flux reactor at the ILL in Grenoble. Measurements were performed for various source geometries, dependent on converter mass, moderator surface and extraction voltages. The results lead to an optimised design of the in-pile positron source which will be implemented at the Munich research reactor FRM-II. The positron source consists of platinum foils acting as gamma-e sup + e sup - -converter and positron moderator. Due to the negative positron work function moderation in heated platinum leads to emission of monoenergetic positrons. The positron work function of polycrystalline platinum was determined to 1.95(5) eV. After acceleration to several keV by four electrical lenses the beam was magnetically guided in a solenoid field of 7.5 mT leading to a NaI-detector in order to detect the 511 keV gamma-radiation of the annihilating positrons. The posi...

  17. Optoelectronic method for determining platinum in biological products

    Science.gov (United States)

    Radu, Simona; Ionicǎ, Mihai; Macovei, Radu Alexandru; Caragea, Genica; Forje, Mǎrgǎrita; Grecu, Iulia; Vlǎdescu, Marian; Viscol, Oana

    2016-12-01

    Of all platinum metals, platinum has the most uses and it's the most abundant and most easily to be processed. Its use in auto catalysts results in environmental contamination of crowded cities and high-traffic roads. In medicine, Pt is used as a cytostatic drug. In order to study the degree of contamination of the population with Pt or the correctness of treatment with Pt, it has been developed a method for its determination from urine or blood samples with a system Graphite Furnance - Atomic Absorption Spectrometer, (GF-AAS) Varian. There are presented the methods of sampling processing for blood or urine that followed the digest of the organic matrix. In the determination of the operating parameters for the system GF-AAS, was aimed the reducing of the nonanatomic absorbance by optimizing the drying temperatures, the calcination and atomization temperatures and the removal of the nonanatomic absorbance with D2 lamp. As a result of the use of the method are presented the concentrations of Pt in the blood or urine of a group of patients in Bucharest, a city with heavy traffic of vehicles. GF-AAS method presented is sensitive, reproducible, and relatively easy to apply with an acceptable cost. With this method, the concentration of Pt can be determined from blood and urine, both in order to establish the degree of contamination with Pt and for monitoring cancer therapy with platinum compounds.

  18. Porous platinum-based catalysts for oxygen reduction

    Science.gov (United States)

    Erlebacher, Jonah D; Snyder, Joshua D

    2014-11-25

    A porous metal that comprises platinum and has a specific surface area that is greater than 5 m.sup.2/g and less than 75 m.sup.2/g. A fuel cell includes a first electrode, a second electrode spaced apart from the first electrode, and an electrolyte arranged between the first and the second electrodes. At least one of the first and second electrodes is coated with a porous metal catalyst for oxygen reduction, and the porous metal catalyst comprises platinum and has a specific surface area that is greater than 5 m.sup.2/g and less than 75 m.sup.2/g. A method of producing a porous metal according to an embodiment of the current invention includes producing an alloy consisting essentially of platinum and nickel according to the formula Pt.sub.xNi.sub.1-x, where x is at least 0.01 and less than 0.3; and dealloying the alloy in a substantially pH neutral solution to reduce an amount of nickel in the alloy to produce the porous metal.

  19. In vitro permeation of platinum through African and Caucasian skin.

    Science.gov (United States)

    Franken, A; Eloff, F C; du Plessis, J; Badenhorst, C J; Du Plessis, J L

    2015-02-03

    The majority of the South African workforce are Africans, therefore potential racial differences should be considered in risk and exposure assessments in the workplace. Literature suggests African skin to be a superior barrier against permeation and irritants. Previous in vitro studies on metals only included skin from Caucasian donors, whereas this study compared the permeation of platinum through African and Caucasian skin. A donor solution of 0.3 mg/ml of potassium tetrachloroplatinate (K₂PtCl₄) dissolved in synthetic sweat was applied to the vertical Franz diffusion cells with full thickness abdominal skin. Skin from three female African and three female Caucasian donors were included (n=21). The receptor solution was removed at various intervals during the 24 h experiment, and analysed with high resolution inductively coupled plasma-mass spectrometry (ICP-MS). Skin was digested and analysed by inductively coupled plasma-optical emission spectrometry (ICP-OES). Significantly higher permeation of platinum through intact African skin (p=0.044), as well as a significantly higher mass of platinum retention in African skin in comparison with Caucasian skin (p=0.002) occurred. Significant inter-donor variation was found in both racial groups (pplatinum salts. These results are contradictory to limited literature suggesting a superior barrier in African skin and further investigation is necessary to explain the higher permeation through African skin.

  20. A Single Platinum Microelectrode for Identifying Soft Drink Samples

    Directory of Open Access Journals (Sweden)

    Lígia Bueno

    2012-01-01

    Full Text Available Cyclic voltammograms recorded with a single platinum microelectrode were used along with a non-supervised pattern recognition, namely, Principal Component Analysis, to conduct a qualitative analysis of sixteen different brands of carbonated soft drinks (Kuat, Soda Antarctica, H2OH!, Sprite 2.0, Guarana Antarctica, Guarana Antarctica Zero, Coca-Cola, Coca-Cola Zero, Coca-Cola Plus, Pepsi, Pepsi Light, Pepsi Twist, Pepsi Twist Light, Pepsi Twist 3, Schin Cola, and Classic Dillar’s. In this analysis, soft drink samples were not subjected to pre-treatment. Good differentiation among all the analysed soft drinks was achieved using the voltammetric data. An analysis of the loading plots shows that the potentials of −0.65 V, −0.4 V, 0.4 V, and 0.750 V facilitated the discrimination process. The electrochemical processes related to this potential are the reduction of hydrogen ions and inhibition of the platinum oxidation by the caffeine adsorption on the electrode surface. Additionally, the single platinum microelectrode was useful for the quality control of the soft drink samples, as it helped to identify the time at which the beverage was opened.

  1. Effects of Fusion Tack Welds on Self-Reacting Friction Stir Welds

    Science.gov (United States)

    Nunes, A. C., Jr.; Pendleton, M. L.; Brooke, S. A.; Russell, C. K.

    2012-01-01

    In order to know whether fusion tack welds would affect the strength of self-reacting friction stir seam welds in 2195-T87 aluminum alloy, the fracture stresses of 144 tensile test coupons cut from 24 welded panels containing segments of friction stir welds were measured. Each of the panels was welded under unique processing conditions. A measure of the effect of the tack welds for each panel was devised. An analysis of the measures of the tack weld effect supported the hypothesis that fusion tack welds do not affect the strength of self-reacting friction stir welds to a 5% level of confidence.

  2. Application of liposomal technologies for delivery of platinum analogs in oncology.

    Science.gov (United States)

    Liu, Demin; He, Chunbai; Wang, Andrew Z; Lin, Wenbin

    2013-01-01

    Platinum-based chemotherapy, such as cisplatin, oxaliplatin, and carboplatin, is one of the most widely utilized classes of cancer therapeutics. While highly effective, the clinical applications of platinum-based drugs are limited by their toxicity profiles as well as suboptimal pharmacokinetic properties. Therefore, one of the key research areas in oncology has been to develop novel platinum analog drugs and engineer new platinum drug formulations to improve the therapeutic ratio further. Such efforts have led to the development of platinum analogs including nedaplatin, heptaplatin, and lobaplatin. Moreover, reformulating platinum drugs using liposomes has resulted in the development of L-NDPP (Aroplatin™), SPI-77, Lipoplatin™, Lipoxal™, and LiPlaCis®. Liposomes possess several attractive biological activities, including biocompatibility, high drug loading, and improved pharmacokinetics, that are well suited for platinum drug delivery. In this review, we discuss the various platinum drugs and their delivery using liposome-based drug delivery vehicles. We compare and contrast the different liposome platforms as well as speculate on the future of platinum drug delivery research.

  3. Effect of the Platinum Electroplated Layer Thickness on the Coatings' Microstructure

    Science.gov (United States)

    Zagula-Yavorska, Maryana; Gancarczyk, Kamil; Sieniawski, Jan

    2017-03-01

    CMSX 4 and Inconel 625 superalloys were coated by platinum layers (3 and 7 μm thick) in the electroplating process. The heat treatment of platinum layers (at 1,050 ˚C for 2 h) was performed to increase platinum adherence to the superalloys substrate. The diffusion zone obtained on CMSX 4 superalloy (3 and 7 μm platinum thick before heat treatment) consisted of two phases: γ-Ni(Al, Cr) and (Al0.25Pt0.75)Ni3. The diffusion zone obtained on Inconel 625 superalloy (3 μm platinum thick before heat treatment) consisted of the α-Pt(Ni, Cr, Al) phase. Moreover, γ-Ni(Cr, Al) phase was identified. The X-ray diffraction (XRD) results revealed the presence of platinum in the diffusion zone of the heat-treated coating (7 μm platinum thick) on Inconel 625 superalloy. The surface roughness parameter Ra of heat-treated coatings increased with the increase of platinum layers thickness. This was due to the unequal mass flow of platinum and nickel.

  4. Influence of Surface Structure of Platinum Electrodes on Electrooxidation of CO

    Institute of Scientific and Technical Information of China (English)

    XIA Xing-hua; ZHANG Dai; SONG Yan-yan

    2003-01-01

    The oxidation of CO on platinum electrodes in an acid solution was studied with the conventional electrochemical methods and the on-line electrochemical mass spectroscopy. It was found that this reaction is strongly determined by the surface morphology of platinum. The pretreatment of platinum electrodes can change the surface properties dramatically, in consequence it can improve the electrocatalytic activity towards the electrooxidation of CO. The existence of surface active sites on the roughened platinum electrodes can be used to explain its high electrocatalysis towards the oxidation of CO.

  5. Dialkyl bisphosphonate platinum(II) complex as a potential drug for metastatic bone tumor.

    Science.gov (United States)

    Nakatake, Hidetoshi; Ekimoto, Hisao; Aso, Mariko; Ogawa, Atsushi; Yamaguchi, Asami; Suemune, Hiroshi

    2011-01-01

    Bisphosphonates have high affinity for hydroxyapatite (HA), which is abundantly present in bone. Also, platinum complexes are known that have a wide spectrum of antitumor activities. The conjugate of bisphosphonate and a platinum complex might have HA affinity and antitumor activity, and become a drug for metastatic bone tumor. In this study, the authors synthesized platinum complexes that had dialkyl bisphosphonic acid as a ligand, and evaluated the possibility of the synthesized complexes as a drug for metastatic bone tumor. The synthesized dialkyl bisphosphonate platinum(II) complex was characterized, and its stability in an aqueous solution was also confirmed. The synthesized platinum complex showed higher HA affinity than other platinum complexes such as cisplatin and carboplatin in an experiment of adsorption to HA. In vitro, the platinum complex showed tumor growth inhibitory effect stronger than or equal to cisplatin, which is the most commonly used antitumor agent. Moreover, the platinum complex showed a bone absorption inhibitory effect on the osteoclast. These results suggest potential of dialkyl bisphosphonate platinum(II) complexes as a drug for metastatic bone tumor.

  6. Application of liposomal technologies for delivery of platinum analogs in oncology

    Science.gov (United States)

    Liu, Demin; He, Chunbai; Wang, Andrew Z; Lin, Wenbin

    2013-01-01

    Platinum-based chemotherapy, such as cisplatin, oxaliplatin, and carboplatin, is one of the most widely utilized classes of cancer therapeutics. While highly effective, the clinical applications of platinum-based drugs are limited by their toxicity profiles as well as suboptimal pharmacokinetic properties. Therefore, one of the key research areas in oncology has been to develop novel platinum analog drugs and engineer new platinum drug formulations to improve the therapeutic ratio further. Such efforts have led to the development of platinum analogs including nedaplatin, heptaplatin, and lobaplatin. Moreover, reformulating platinum drugs using liposomes has resulted in the development of L-NDPP (Aroplatin™), SPI-77, Lipoplatin™, Lipoxal™, and LiPlaCis®. Liposomes possess several attractive biological activities, including biocompatibility, high drug loading, and improved pharmacokinetics, that are well suited for platinum drug delivery. In this review, we discuss the various platinum drugs and their delivery using liposome-based drug delivery vehicles. We compare and contrast the different liposome platforms as well as speculate on the future of platinum drug delivery research. PMID:24023517

  7. Use of sulfur hexafluoride airflow studies to determine the appropriate number and placement of air monitors in an alpha inhalation exposure laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Newton, G.J.; Hoover, M.D.

    1995-12-01

    Determination of the appropriate number and placement of air monitors in the workplace is quite subjective and is generally one of the more difficult tasks in radiation protection. General guidance for determining the number and placement of air sampling and monitoring instruments has been provided by technical reports such as Mishima, J. These two documents and other published guidelines suggest that some insight into sampler placement can be obtained by conducting airflow studies involving the dilution and clearance of the relatively inert tracer gas sulfur hexafluoride (SF{sub 6}) in sampler placement studies and describes the results of a study done within the ITRI alpha inhalation exposure laboratories. The objectives of the study were to document an appropriate method for conducting SF{sub 6} dispersion studies, and to confirm the appropriate number and placement of air monitors and air samplers within a typical ITRI inhalation exposure laboratory. The results of this study have become part of the technical bases for air sampling and monitoring in the test room.

  8. Reuse of ammonium fluoride generated in the uranium hexafluoride conversion; Reutilizacao do fluoreto de amonio gerado na reconversao do hexafluoreto de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Silva Neto, J.B.; Carvalho, E.F. Urano de; Durazzo, M., E-mail: jbsneto@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Riella, H.G [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil)

    2010-07-01

    The Nuclear Fuel Centre of IPEN / CNEN - SP develops and manufactures dispersion fuel with high uranium concentration to meet the demand of the IEA-R1 reactor and future research reactors planned to be constructed in Brazil. The fuel uses uranium silicide (U{sub 3}Si{sub 2}) dispersed in aluminum. For producing the fuel, the processes for uranium hexafluoride (UF{sub 6}) conversion consist in obtaining U{sub 3}Si{sub 2} and / or U{sub 3}O{sub 8} through the preparation of intermediate compounds, among them ammonium uranyl carbonate - AUC, ammonium diuranate - DUA and uranium tetrafluoride - UF{sub 4}. This work describes a procedure for preparing uranium tetrafluoride by a dry route using as raw material the filtrate generated when producing routinely ammonium uranyl carbonate. The filtrate consists primarily of a solution containing high concentrations of ammonium (NH{sub 4}{sup +}), fluoride (F{sup -}), carbonate (CO{sub 3}{sup --}) and low concentrations of uranium. The procedure is basically the recovery of NH{sub 4}F and uranium, as UF{sub 4}, through the crystallization of ammonium bifluoride (NH{sub 4}HF{sub 2}) and, in a later step, the addition of UO{sub 2}, occurring fluoridation and decomposition. The UF{sub 4} obtained is further diluted in the UF{sub 4} produced routinely at IPEN / CNEN-SP by a wet route process. (author)

  9. [Managment of subretinal heamorrhages within the macular area using intravitreal injections of recombined tissue plasminogen activator, sulphur hexafluoride and ranihizumab--preliminary report].

    Science.gov (United States)

    Miniewicz, Joanna; Kubicka-Trząska, Agnieszka; Karska-Basta, Izabella; Romanowska-Dixon, Boźena

    2015-01-01

    Submacular hemorrhages cause serious vision impairment. Patient observation, waiting for the spontaneous blood reabsorption and resolution of the haemorrhage leads to the severe damage to retinal tissue as a result of scar formation. The paper presents 7 cases of patients with submacular haemorrhages treated with intravitreal injections of recombined tissue plasminogen activator (rtPA) and sulphur hexafluoride (SFG). In 4 cases, the haemorrhage was secondary to AMD, in two cases to trauma, and it was idiopathic in one case. All patients were treated with intravitreal injections of rtPA and SF6 for thrombolysis and pneumatic displacement of haemorrhage outside macular structures. Ranibizumab was additionally administered to patients with age-related macular degeneration. Such treatment improved visual acuity in all patients, reducing the central retinal thickness as shown in follow-up optical coherence tomography. The presented treatment of submacular hemorrhages with intravitreal injections of rtPA and SF6 provided good results, but in order to develop a standard management algorithm for this disease, the analysis of larger patient sample is required.

  10. One-year outcome after Descemet membrane endothelial keratoplasty (DMEK) comparing sulfur hexafluoride (SF6) 20% versus 100% air for anterior chamber tamponade.

    Science.gov (United States)

    Schaub, Friederike; Enders, Philip; Snijders, Katharina; Schrittenlocher, Silvia; Siebelmann, Sebastian; Heindl, Ludwig M; Bachmann, Björn O; Cursiefen, Claus

    2017-07-01

    To investigate 1-year clinical outcome and complication rates following Descemet membrane endothelial keratoplasty (DMEK) with sulfur hexafluoride 20% (SF620%) anterior chamber tamponade compared with conventionally used 100% air for primary graft attachment during DMEK surgery. Records of 1112 consecutive DMEKs were reviewed retrospectively and grouped by anterior chamber tamponade used during DMEK surgery (SF620% vs 100% air). Outcome measures included intraocular pressure (IOP), best spectacle-corrected visual acuity (BSCVA), endothelial cell density (ECD) and central corneal thickness (CCT) at 1, 3, 6 and 12 months after DMEK surgery. Complication rates were assessed, including intraoperative and postoperative complications, and graft detachment rate requiring rebubbling. A total of 854 cases were included in this study. In 105 cases (12.3%), DMEK was performed with SF620%, and in 749 cases (87.7%) 100% air was used for anterior chamber tamponade. Outcome results for IOP, BSCVA, ECD and CCT at all follow-up time points were comparable for both anterior chamber tamponade groups without statistical significant differences (p≥0.05), but graft detachment rate requiring rebubbling was significantly lower in the SF620% group (ptamponade does not seem to negatively affect the clinical outcome of DMEK surgery within the first postoperative year, use of SF620% significantly reduces the rate of rebubblings. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  11. Fabrication of platinum coated nanoporous gold film electrode: A nanostructured ultra low-platinum loading electrocatalyst for hydrogen evolution reaction

    Energy Technology Data Exchange (ETDEWEB)

    Kiani, Abolfazl; Hatami, Somayeh [Department of Chemistry, Faculty of Science, University of Isfahan, Isfahan (Iran)

    2010-06-15

    The electrolytic hydrogen evolution reaction (HER) on platinum coated nanoporous gold film (PtNPGF) electrode is demonstrated. The deposition of platinum occurred as a spontaneous redox process in which a copper layer, obtained by underpotential deposition, was oxidized by platinum ions, which were reduced and simultaneously deposited. The present method could provide a very low Pt-loading electrode and the results demonstrated that ultra thin Pt coating effected efficiently and behaved as the nanostructured Pt for electrocatalytic hydrogen evolution reaction. The loading of Pt was calculated as 4.2 x 10{sup -3} {mu}g cm{sup -2} for PtNPGF electrode. The current density at -0.4 V and -0.8 V vs. Ag/AgCl was as high as 0.66 A {mu}g{sup -1} Pt and 3 A {mu}g{sup -1} Pt, respectively and the j{sub 0} was evaluated as 0.03 mA cm{sup -2} or 8 mA {mu}g{sup -1} Pt. The results indicated that increasing electrode area had no catalytic effect, but the nanostructure nature of as-fabricated electrode and submonolayer deposition of copper resulted in electrocatalytic activity for PtNPGF electrode. (author)

  12. Evaluation of the Effectiveness of Conceptual Change Texts in the REACT Strategy

    Science.gov (United States)

    Ültay, Neslihan; Durukan, Ümmü Gülsüm; Ültay, Eser

    2015-01-01

    This study aimed to investigate the effect of conceptual change text (CCT) in the REACT strategy for students' conceptions of solutions. A quasi-experimental method was used in the study. The study was carried out in the spring term of the 2012-2013 academic year with 61 freshmen students (aged 18-20 years) studying in the Elementary Education…

  13. Identification of a Campylobacter jejuni protein that cross-reacts with cholera toxin.

    Science.gov (United States)

    Albert, M John; Haridas, Shilpa; Steer, David; Dhaunsi, Gursev S; Smith, A Ian; Adler, Ben

    2007-06-01

    The question of whether Campylobacter jejuni produces a cholera toxin-like toxin (CTLT) has been controversial. The objective of this study was to identify the factor that cross-reacts with CT from C. jejuni. Filtrates of C. jejuni grown in four different liquid media reported to promote CTLT production were tested by Chinese hamster ovary (CHO) cell elongation assay and for reactivity with CT antibody using GM1 ganglioside enzyme-linked immunosorbent assay (ELISA) and immunoblotting. Protein sequence was determined by matrix-assisted laser desorption ionization-time of flight (MALDI TOF-TOF). Filtrates from seven reference strains reported to produce CTLT and from 80 clinical strains were negative in the CHO cell assay, but those from three reference strains and 16 clinical strains were positive by GM1 ELISA. All strains tested, including C. jejuni NCTC 11168, which does not contain a CT gene homologue, possessed a 53-kDa protein which reacted with CT antibody by immunoblotting. This band was identified as the major outer membrane protein, PorA, of C. jejuni. CT antibody reacted by immunoblotting with a recombinant PorA, but antibody to the recombinant PorA did not react with CT. Our results indicate that C. jejuni does not produce a functional CTLT, but the reactivity of PorA with CT antibody would lead to the erroneous conclusion that C. jejuni produces a functional CTLT.

  14. Identification of a Campylobacter jejuni Protein That Cross-Reacts with Cholera Toxin▿

    Science.gov (United States)

    Albert, M. John; Haridas, Shilpa; Steer, David; Dhaunsi, Gursev S.; Smith, A. Ian; Adler, Ben

    2007-01-01

    The question of whether Campylobacter jejuni produces a cholera toxin-like toxin (CTLT) has been controversial. The objective of this study was to identify the factor that cross-reacts with CT from C. jejuni. Filtrates of C. jejuni grown in four different liquid media reported to promote CTLT production were tested by Chinese hamster ovary (CHO) cell elongation assay and for reactivity with CT antibody using GM1 ganglioside enzyme-linked immunosorbent assay (ELISA) and immunoblotting. Protein sequence was determined by matrix-assisted laser desorption ionization-time of flight (MALDI TOF-TOF). Filtrates from seven reference strains reported to produce CTLT and from 80 clinical strains were negative in the CHO cell assay, but those from three reference strains and 16 clinical strains were positive by GM1 ELISA. All strains tested, including C. jejuni NCTC 11168, which does not contain a CT gene homologue, possessed a 53-kDa protein which reacted with CT antibody by immunoblotting. This band was identified as the major outer membrane protein, PorA, of C. jejuni. CT antibody reacted by immunoblotting with a recombinant PorA, but antibody to the recombinant PorA did not react with CT. Our results indicate that C. jejuni does not produce a functional CTLT, but the reactivity of PorA with CT antibody would lead to the erroneous conclusion that C. jejuni produces a functional CTLT. PMID:17438040

  15. A framework for the design of reacting systems with phase transfer catalysis

    DEFF Research Database (Denmark)

    Piccolo, Chiara; Shaw, Andrew; Hodges, George;

    2012-01-01

    A generic modelling framework for phase transition catalyst based reacting systems has been developed and converted into a software tool. The modelling framework accommodates models of different types representing different sub-systems of the PTCbased reactive system; databases of model parameter...

  16. A framework for the design of reacting systems with phase transfer catalysis

    DEFF Research Database (Denmark)

    Piccolo, Chiara; Shaw, Andrew; Hodges, George;

    A generic modelling framework for phase transition catalyst based reacting systems has been developed and converted into a software tool. The modelling framework accommodates models of different types representing different sub-systems of the PTCbased reactive system; databases of model parameter...

  17. A NEW METHOD TO DETECT ACROSOME-REACTED SPERMATOZOA USING BIOTINYLATED SOYBEAN TRYPSIN-INHIBITOR

    NARCIS (Netherlands)

    ARTS, EGJM; KUIKEN, J; JAGER, S

    1994-01-01

    Objective: To develop a method to detect acrosome-reacted spermatozoa on human zonae pellucidae using only commercially available reagents and without need for sperm fixation. Design: Sperm head labeling with biotinylated soybean trypsin inhibitor (SBTI-biotin) was compared with results of a known m

  18. Non-equilibrium reacting gas flows kinetic theory of transport and relaxation processes

    CERN Document Server

    Nagnibeda, Ekaterina; Nagnibeda, Ekaterina

    2009-01-01

    This volume develops the kinetic theory of transport phenomena and relaxation processes in the flows of reacting gas mixtures. The theory is applied to the modeling of non-equilibrium flows behind strong shock waves, in the boundary layer, and in nozzles.

  19. Serum and plasma fibronectin binds to complement reacted immune complexes primarily via Clq

    DEFF Research Database (Denmark)

    Baatrup, G; Svehag, S E

    1986-01-01

    The binding of fibronectin to human Clq, C3b, and complement-reacted immune complexes (IC) was investigated by enzyme-linked immunosorbent assays. Microplates were coated with BSA followed by incubation with rabbit-anti-BSA IgG or F(ab')2 fragments of rabbit anti-BSA. Incubation of the solid phas...

  20. Imines that React with Phenols in Water over a Wide pH Range

    Science.gov (United States)

    Minakawa, Maki; Guo, Hai-Ming

    2009-01-01

    Cyclic imine derivatives that react with phenols, including tyrosine residues of peptides, have been developed. Reactions of the imines with phenols proceeded in water over a wide pH range (pH 2-10) at room temperature to 37 °C and afforded Mannich products without the need of additional catalysts. PMID:18844415

  1. Heat and mass transfer for turbulent flow of chemically reacting gas in eccentric annular channels

    Science.gov (United States)

    Besedina, T. V.; Tverkovkin, B. E.; Udot, A. V.; Yakushev, A. P.

    1987-08-01

    An algorithm is proposed for calculating the velocity, temperature, and concentration fields under conditions of cooling of a cylindrical heat-releasing rod, placed off-center in a circular casing pipe, by a longitudinal flow of chemically reacting gas [N2O4].

  2. Flu Plan: Colleges Struggle with How They Would React to a Pandemic

    Science.gov (United States)

    Guterman, Lila

    2005-01-01

    Administrators of various education schools have vowed to ready their institutions for the next major disaster of flu pandemic. While a few colleges with expertise or interest in the area are trying to determine how their campuses should react to a flu pandemic, most seem to be struggling with how to fit all the unknowns of such a crisis into…

  3. Prediction of reacting atoms for the major biotransformation reactions of organic xenobiotics.

    Science.gov (United States)

    Rudik, Anastasia V; Dmitriev, Alexander V; Lagunin, Alexey A; Filimonov, Dmitry A; Poroikov, Vladimir V

    2016-01-01

    The knowledge of drug metabolite structures is essential at the early stage of drug discovery to understand the potential liabilities and risks connected with biotransformation. The determination of the site of a molecule at which a particular metabolic reaction occurs could be used as a starting point for metabolite identification. The prediction of the site of metabolism does not always correspond to the particular atom that is modified by the enzyme but rather is often associated with a group of atoms. To overcome this problem, we propose to operate with the term "reacting atom", corresponding to a single atom in the substrate that is modified during the biotransformation reaction. The prediction of the reacting atom(s) in a molecule for the major classes of biotransformation reactions is necessary to generate drug metabolites. Substrates of the major human cytochromes P450 and UDP-glucuronosyltransferases from the Biovia Metabolite database were divided into nine groups according to their reaction classes, which are aliphatic and aromatic hydroxylation, N- and O-glucuronidation, N-, S- and C-oxidation, and N- and O-dealkylation. Each training set consists of positive and negative examples of structures with one labelled atom. In the positive examples, the labelled atom is the reacting atom of a particular reaction that changed adjacency. Negative examples represent non-reacting atoms of a particular reaction. We used Labelled Multilevel Neighbourhoods of Atoms descriptors for the designation of reacting atoms. A Bayesian-like algorithm was applied to estimate the structure-activity relationships. The average invariant accuracy of prediction obtained in leave-one-out and 20-fold cross-validation procedures for five human isoforms of cytochrome P450 and all isoforms of UDP-glucuronosyltransferase varies from 0.86 to 0.99 (0.96 on average). We report that reacting atoms may be predicted with reasonable accuracy for the major classes of metabolic reactions

  4. Elution of platinum from carboplatin-impregnated calcium sulfate hemihydrate beads in vitro.

    Science.gov (United States)

    Tulipan, Rachel J; Phillips, Heidi; Garrett, Laura D; Dirikolu, Levent; Mitchell, Mark A

    2016-11-01

    OBJECTIVE To characterize the elution of platinum from carboplatin-impregnated calcium sulfate hemihydrate (CSH) beads in vitro. SAMPLE 60 carboplatin-impregnated CSH beads and 9 CSH beads without added carboplatin (controls). PROCEDURES Carboplatin-impregnated CSH beads (each containing 4.6 mg of carboplatin [2.4 mg of platinum]) were placed into separate 10-mL plastic tubes containing 5 mL of PBSS in groups of 1, 3, 6, or 10; 3 control beads were placed into a single tube of PBSS at the same volume. Experiments were conducted in triplicate at 37°C and a pH of 7.4 with constant agitation. Eluent samples were collected at 1, 2, 3, 6, 12, 24, and 72 hours. Samples were analyzed for platinum content by inductively coupled plasma-mass spectrometry. RESULTS The mean concentration of platinum released per carboplatin-impregnated bead over 72 hours was 445.3 mg/L. Cumulative concentrations of platinum eluted increased as the number of beads per tube increased. There was a significant difference in platinum concentrations over time, with values increasing over the first 12 hours and then declining for all tubes. There was also a significant difference in percentage of total incorporated platinum released into tubes with different numbers of beads: the percentage of eluted platinum was higher in tubes containing 1 or 3 beads than in those containing 6 or 10 beads. CONCLUSIONS AND CLINICAL RELEVANCE Carboplatin-impregnated CSH beads eluted platinum over 72 hours. Further studies are needed to determine whether implantation of carboplatin-impregnated CSH beads results in detectable levels of platinum systemically and whether the platinum concentrations eluted locally are toxic to tumor cells.

  5. Keefektifan Strategi Pembelajaran React Pada Kemampuan Siswa Kelas VII Aspek Komunikasi Matematis

    Directory of Open Access Journals (Sweden)

    A.T. Arifin

    2014-06-01

    Full Text Available AbstrakTujuan penelitian ini adalah mengetahui pembelajaran dengan strategi REACT efektif ter-hadap kemampuan komunikasi matematis siswa. Metode pengumpulan data dilakukan de-ngan metode dokumentasi, tes, dan observasi. Hasil uji proporsi menunjukkan bahwa hasil belajar siswa kelas eksperimen pada aspek kemampuan komunikasi matematis telah men-capai ketuntasan klasikal, mencapai lebih dari 80 % yaitu sebesar 96,7%. Dilihat dari nilai rata-rata tes kemampuan komunikasi matematis kelas eksperimen  adalah 83,61 sedangkan kelas kontrol adalah 73,79 dapat disimpulkan bahwa kemampuan komunikasi matematis siswa kelas eksperimen lebih baik daripada kemampuan komunikasi matematis siswa kon-trol. Hasil penelitian menunjukkan bahwa penerapan strategi pembelajaran REACT efektif terhadap kemampuan komunikasi matematis siswa materi segiempat kelas VII SMP Negeri 1 Gembong. Kata kunci:      keefektifan, kemampuan komunikasi matematis, Relating Experiencing Applying Cooperating Transferring (REACT  AbstractThe purpose of this study was to determine the effectiveness of the application of REACT learning strategy approach to mathematic communication ability of students. Methods of data collection is done by the method of documentation, testing, and observation. The test results showed that the proportion of student learning outcomes in the experimental class with the aspects of mathematic communication ability has reached the classical completeness, reached more than 80% is equal to 96.7%. Judging from the value of the average test learners' ability to mathematic communication experimental class was 83.61 while the control class is 73.79 it can be concluded that the mathematic communication skills of learners experimental classes are better than mathematic communication abilities of learners control class. The results showed that the application of REACT learning strategy approach effective to mathematic communication abilities of students of class VII

  6. Determinants of ototoxicity in 451 platinum-treated Dutch survivors of childhood cancer : A DCOG late-effects study

    NARCIS (Netherlands)

    Clemens, Eva; de Vries, Andrica C.; Pluijm, Saskia F.; Zehnhoff-Dinnesen, Antoinette Am; Tissing, Wim J.; Loonen, Jacqueline J.; van Dulmen-den Broeder, Eline; Bresters, Dorine; Versluys, Birgitta; Kremer, Leontien C.; van der Pal, Heleen J.; van Grotel, Martine; van den Heuvel-Eibrink, Marry M.

    2016-01-01

    Platinum-containing chemotherapeutics are efficacious for a variety of pediatric malignancies, nevertheless these drugs can induce ototoxicity. However, ototoxicity data on large cohorts of childhood cancer survivors (CCSs) who received platinum agents, but not cranial irradiation are scarce.

  7. Structure and reactivity of a unique Y-shaped tricoordinate bis(silyl)platinum(II)-NHC complex

    NARCIS (Netherlands)

    Berthon-Gelloz, G.; de Bruin, B.; Tinant, B.; Markó, I.E.

    2009-01-01

    A unique, three-coordinate Y-shaped bis(silyl)platinum(II) complex was isolated and characterized. DFT studies on a model system shed light on the nature of this unusual coordination mode for platinum(II).

  8. Differing Event-Related Patterns of Gamma-Band Power in Brain Waves of Fast- and Slow-Reacting Subjects

    Science.gov (United States)

    1994-05-01

    Wilhelm Wundt proposed that there are two types of subjects in sim- ple RT experiments: fast-reacting subjects, who respond before they fully...quickly as possible to auditory stimuli. This result appears to confirm long-standing speculations of Wundt that fast- and slow-reacting subjects...accord with the hypothesis of Wundt and others that slower ("sensorial") responders wait to fully perceive a stimulus and then react to their perception

  9. Distribution of platinum in patients treated with cisplatin determined by radiochemical neutron activation analysis

    DEFF Research Database (Denmark)

    Heydorn, K.; Rietz, B.; Krarup-Hansen, A.

    1998-01-01

    tissue from 2 male and 2 female patients, treated with different doses of cisplatin. Platinum and gold was determined in all samples. Results for platinum were found to depend not only on the total amount of cisplatin ingested, but also on the time between the last dose and death. Highest concentrations...

  10. Metal Oxide-Supported Platinum Overlayers as Proton-Exchange Membrane Fuel Cell Cathodes

    DEFF Research Database (Denmark)

    Tripkovic, Vladimir; Abild-Pedersen, Frank; Studt, Felix

    2012-01-01

    We investigated the activity and stability of n=(1, 2, 3) platinum layers supported on a number of rutile metal oxides (MO2; M=Ti, Sn, Ta, Nb, Hf and Zr). A suitable oxide support can alleviate the problem of carbon corrosion and platinum dissolution in Pt/C catalysts. Moreover, it can increase t...

  11. A Tin(IV) Porphyrin with Two Axial Organometallic NCN-Pincer Platinum Units

    NARCIS (Netherlands)

    Suijkerbuijk, B.M.J.M.; Tooke, D.M.; Spek, A.L.; van Koten, G.; Klein Gebbink, R.J.M.

    2007-01-01

    A tin(IV) porphyrin was combined with two axial NCN-pincer platinum(II) fragments by utilizing the oxophilicity of the apical positions on the tin atom and the acidic nature of the NCN-pincer platinum derived benzoic acid. The solid-state structure determined by X-ray crystallography revealed some

  12. Recent Approaches to Platinum(IV) Prodrugs: A Variety of Strategies for Enhanced Delivery and Efficacy.

    Science.gov (United States)

    Najjar, Anas; Rajabi, Naeema; Karaman, Rafik

    2017-01-01

    Intensive efforts have been implemented to improve the efficacy of platinum complexes especially with emerging cisplatin resistance and elevated cancer deaths. Platinum(IV) agents show better pharmacokinetics and decreased side effects compared to Platinum(II) agents. This review aims to summarize and categorize the strategies being employed to improve the efficacy of Platinum-based anticancer agents in recent years. Nanoparticles and nanoplatforms offer a vast variety of strategies in targeting specific tumor types and delivering one or two lethal drugs simultaneously. Theranostic agents are being developed to achieve enhanced imaging and provide further insight into the activity of platinum containing chemotherapy. Moreover, photoactivation of Pt(IV) prodrugs specifically at the tumor site is gaining attention due to a controlled activity. A platinum agent formulated as large multi-activity complex is the most common strategy being employed. Platinum(IV) agents offer great potential in targeting, increasing efficacy, and decreasing toxicity of Platinum-based anticancer agents. The strategies being employed are aiming to increase specificity and targeting as well as provide more potent agents. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  13. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT, HVLP COATING EQUIPMENT, SHARPE MANUFACTURING COMPANY PLATINUM 2012 HVLP SPRAY GUN

    Science.gov (United States)

    This report presents the results of the verification test of the Sharpe Platinum 2013 high-volume, low-pressure gravity-feed spray gun, hereafter referred to as the Sharpe Platinum, which is designed for use in automotive refinishing. The test coating chosen by Sharpe Manufacturi...

  14. The determination of platinum in tissue of different human organs by means of neutron activation analysis

    DEFF Research Database (Denmark)

    Rietz, Bernd; Heydorn, Kaj; Krarup-Hansen, Anders

    2002-01-01

    . It was demonstrated that radiochemical neutron activation analysis can be used for these studies because of its sensitivity and precision and a low detection limit for platinum (similar to1 ng). Tissues of the following organs were analyzed for platinum: liver, kidney, testis, lung, pancreas and muscle. This study...

  15. SEROTONIN METABOLISM FOLLOWING PLATINUM-BASED CHEMOTHERAPY COMBINED WITH THE SEROTONIN TYPE-3 ANTAGONIST TROPISETRON

    NARCIS (Netherlands)

    SCHRODER, CP; VANDERGRAAF, WTA; KEMA, IP; GROENEWEGEN, A; SLEIJFER, DT; DEVRIES, EGE

    1995-01-01

    The administration of platinum-based chemotherapy induces serotonin release from the enterochromaffin cells, causing nausea and vomiting. This study was conducted to evaluate parameters of serotonin metabolism following platinum-based chemotherapy given in combination with the serotonin type-3 antag

  16. Lack of nephrotoxicity of new oral platinum drug JM216 in lung cancer patients

    NARCIS (Netherlands)

    Fokkema, E; de Vries, EGE; Meijer, S; Groen, HJM

    Purpose: The purpose of this study was to assess renal function in patients treated with the oral platinum drug JM216 [bisacetato-ammine-dichloro-cyclohexylamine-platinum (IV)I, since the effects of JM216 on renal function have only partly been investigated using serum parameters or Cr-51-EDTA

  17. Enzymatic recovery of platinum (IV) from industrial wastewater using a biosulphidogenic hydrogenase

    CSIR Research Space (South Africa)

    Rashamuse, KJ

    2008-04-01

    Full Text Available this treatment process suggesting that platinum sulphide was not formed and supporting the argument that the increased amount (78%) of platinum removal from the industrial wastewater by the growing SRB cells was due to more hydrogenase/cytochrome c3 enzyme...

  18. 78 FR 11954 - Revised Pricing Grid for Gold and Platinum Products

    Science.gov (United States)

    2013-02-20

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE TREASURY United States Mint Revised Pricing Grid for Gold and Platinum Products AGENCY: United States Mint... grid for 2013 gold and platinum products. Please see the grid following signature. DATES: This...

  19. Electron-beam-induced deposition of platinum at low landing energies

    NARCIS (Netherlands)

    Botman, A.; De Winter, D.A.M.; Mulders, J.J.L.

    2008-01-01

    Electron-beam-induced deposition of platinum from methylcyclopentadienyl-platinum-trimethyl was performed with a focused electron beam at low landing energies, down to 10 eV. The deposition growth rate is maximal at 140 eV, with the process being over ten times more efficient than at 20 kV. No signi

  20. Electrocatalytic Activity of Platinum Particles Electrodeposited onto Poly(vinylpyridine) Films

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The electrocatalytic properties of platinum microparticles incorporated into poly- (vinylpyridine) (PVP) films, a conducting polymer with good conductivity and stability, were investigated for hydrogen evolution and formic acid electrooxidation in acidic media. It was found that the catalytic effects depend mainly on the size and amounts of the platinum microparticles dispersed in the polymer layer.

  1. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT, HVLP COATING EQUIPMENT, SHARPE MANUFACTURING COMPANY PLATINUM 2012 HVLP SPRAY GUN

    Science.gov (United States)

    This report presents the results of the verification test of the Sharpe Platinum 2013 high-volume, low-pressure gravity-feed spray gun, hereafter referred to as the Sharpe Platinum, which is designed for use in automotive refinishing. The test coating chosen by Sharpe Manufacturi...

  2. Structure of matrix metalloproteinase-3 with a platinum-based inhibitor.

    Science.gov (United States)

    Belviso, Benny Danilo; Caliandro, Rocco; Siliqi, Dritan; Calderone, Vito; Arnesano, Fabio; Natile, Giovanni

    2013-06-18

    An X-ray investigation has been performed with the aim of characterizing the binding sites of a platinum-based inhibitor (K[PtCl3(DMSO)]) of matrix metalloproteinase-3 (stromelysin-1). The platinum complex targets His224 in the S1' specificity loop, representing the first step in the selective inhibition process (PDB ID code 4JA1).

  3. Advances in the synthesis mulitmetallic systems: hydroxyl group protection in aryldiamine platinum species

    NARCIS (Netherlands)

    Koten, G. van; Davies, P.J.; Grove, D.M.

    1997-01-01

    A multimetallic system containing three platinum atoms has been synthesized through use of an (aryldiamine)platinum complex with a protected hydroxyl group which, after deprotection, is coupled with the trisubstituted aryl molecule 1,3,5-tris(chlorocarbonyl)benzene that provides the core moiety. The

  4. The interaction of platinum-based drugs with native biologically relevant proteins

    NARCIS (Netherlands)

    Brauckmann, Christine; Wehe, Christoph A.; Kieshauer, Michael; Lanvers-Kaminsky, Claudia; Sperling, Michael; Karst, Uwe

    2013-01-01

    This study focuses on the identification of the products that are formed upon binding of therapeutically relevant platinum complexes to proteins like beta-lactoglobulin A (LGA), human serum albumin (HSA), or human hemoglobin (HB). The respective proteins were incubated with the platinum-based antica

  5. Design and development of polynuclear ruthenium and platinum polypyridyl complexes in search of new anticancer agents

    NARCIS (Netherlands)

    Schilden, Karlijn van der

    2006-01-01

    The research described in this Ph.D. Thesis has been devoted to the design and development of polynuclear polypyridyl ruthenium and ruthenium-platinum complexes in search of new anticancer agents. A variety of polynuclear ruthenium and ruthenium-platinum complexes has been synthesized with a long an

  6. Determination of platinum in waste platinum-loaded carbon catalyst samples using microwave-assisted sample digestion and ICP-OES

    Science.gov (United States)

    Ma, Yinbiao; Wei, Xiaojuan

    2017-04-01

    A novel method for the determination of platinum in waste platinum-loaded carbon catalyst samples was established by inductively coupled plasma optical emission spectrometry after samples digested by microwave oven with aqua regia. Such experiment conditions were investigated as the influence of sample digestion methods, digestion time, digestion temperature and interfering ions on the determination. Under the optimized conditions, the linear range of calibration graph for Pt was 0 ˜ 200.00 mg L-1, and the recovery was 95.67% ˜ 104.29%. The relative standard deviation (RSDs) for Pt was 1.78 %. The proposed method was applied to determine the same samples with atomic absorption spectrometry with the results consistently, which is suitable for the determination of platinum in waste platinum-loaded carbon catalyst samples.

  7. Textured strontium titanate layers on platinum by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Blomberg, T., E-mail: tom.blomberg@asm.com [ASM Microchemistry Ltd., Vaeinoe Auerin katu 12 A, 00560 Helsinki (Finland); Anttila, J.; Haukka, S.; Tuominen, M. [ASM Microchemistry Ltd., Vaeinoe Auerin katu 12 A, 00560 Helsinki (Finland); Lukosius, M.; Wenger, Ch. [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); Saukkonen, T. [Aalto University, Puumiehenkuja 3, 02150 Espoo (Finland)

    2012-08-31

    Formation of textured strontium titanate (STO) layers with large lateral grain size (0.2-1 {mu}m) and low X-ray reflectivity roughness ({approx} 1.36 nm) on Pt electrodes by industry proven atomic layer deposition (ALD) method is demonstrated. Sr(t-Bu{sub 3}Cp){sub 2}, Ti(OMe){sub 4} and O{sub 3} precursors at 250 Degree-Sign C were used to deposit Sr rich STO on Pt/Ti/SiO{sub 2}/Si Empty-Set 200 mm substrates. After crystallization post deposition annealing at 600 Degree-Sign C in air, most of the STO grains showed a preferential orientation of the {l_brace}001{r_brace} plane parallel to the substrate surface, although other orientations were also present. Cross sectional and plan view transmission electron microscopy and electron diffraction analysis revealed more than an order of magnitude larger lateral grain sizes for the STO compared to the underlying multicrystalline {l_brace}111{r_brace} oriented platinum electrode. The combination of platinum bottom electrodes with ALD STO(O{sub 3}) shows a promising path towards the formation of single oriented STO film. - Highlights: Black-Right-Pointing-Pointer Amorphous strontium titanate (STO) on platinum formed a textured film after annealing. Black-Right-Pointing-Pointer Single crystal domains in 60 nm STO film were 0.2-1 {mu}m wide. Black-Right-Pointing-Pointer Most STO grains were {l_brace}001{r_brace} oriented.

  8. Rumpling phenomenon in platinum modified Ni-Al alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zimmerman, Benjamin Joseph [Iowa State Univ., Ames, IA (United States)

    2005-05-01

    Surface undulations known as rumpling have been shown to develop at the surface of bond coats used in advanced thermal barrier coating systems. Rumpling can result in cracking and eventual spallation of the top coat. Many mechanisms to explain rumpling have been proposed, and among them is a martensitic transformation. High-temperature x-ray diffraction, differential scanning calorimetry and potentiometry were used to investigate the nature of the martensitic transformation in bulk platinum-modified nickel aluminides. It was found that the martensitic transformation has strong time dependence and can form over a range of temperatures. Cyclic oxidation experiments were performed on the bulk alloys to investigate the effect of the martensitic transformation on surface rumpling. It was found that the occurrence of rumpling was associated with the martensitic transformation. The degree of rumpling was found to increase with an increasing number of cycles and was independent of the heating and cooling rates used. The thickness of the oxide layer at the surface of the samples had a significant impact on the amplitude of the resulting undulations, with amplitude increasing with increasing oxide-layer thickness. Rumpling was also observed in an alloy based on the γ-γ' region of the nickel-aluminum-platinum phase diagram. Rumpling in this alloy was found to occur during isothermal oxidation and is associated with a subsurface layer containing a platinum-rich phase known as a. Rumpling in both alloy systems may be explained by creep deformation of a weakened subsurface layer in response to the compressive stresses in the thermally grown oxide layer.

  9. Extraction of gold, palladium, and platinum from acidic media with cyclic sulfoxide derivative

    Institute of Scientific and Technical Information of China (English)

    Songping Wu; Guobang Gu

    2007-01-01

    The extraction of gold (Ⅲ), palladium (Ⅱ), and platinum (Ⅳ) from the acidic media with the cyclic sulfoxide derivative of a-dodecyl-tetrahydrothiophene 1-oxide (dtmso) was investigated. Gold (Ⅲ), palladium (Ⅱ), and platinum (Ⅳ) could be separated from the acidic media with suitable sulfoxide concentration and acidity. The extraction reaction of gold (Ⅲ), palladium (Ⅱ) or platinum (Ⅳ) is exothermic when dtmso is used as an extracting reagent. The coordination number was studied by the slope method. The results indicate that, in high acidity, the dtmso coordination number for extracting gold (Ⅲ) or palladium (Ⅱ) is 3, and that for platinum (Ⅳ) is 2. UV and FT-IR spectra were used to analyze the structure of the complex. Gold (Ⅲ) is coordinated with the oxygen atom in S=O group in dtmso, and palladium (Ⅱ) or platinum (Ⅳ) is coordinated with the sulfur atom in S=O group in dtmso.

  10. Development of Platinum(iv) Complexes as Anticancer Prodrugs: the Story so Far

    Science.gov (United States)

    Wong, Daniel Yuan Qiang; Ang, Wee Han

    2012-06-01

    The serendipitous discovery of the antitumor properties of cisplatin by Barnett Rosenberg some forty years ago brought about a paradigm shift in the field of medicinal chemistry and challenged conventional thinking regarding the role of potentially toxic heavy metals in drugs. Platinum(II)-based anticancer drugs have since become some of the most effective and widely-used drugs in a clinician's arsenal and have saved countless lives. However, they are limited by high toxicity, severe side-effects and the incidence of drug resistance. In recent years, attention has shifted to stable platinum(IV) complexes as anticancer prodrugs. By exploiting the unique chemical and structural attributes of their scaffolds, these platinum(IV) prodrugs offer new strategies of targeting and killing cancer cells. This review summarizes the development of anticancer platinum(IV) prodrugs to date and some of the exciting strategies that utilise the platinum(IV) construct as targeted chemotherapeutic agents against cancer.

  11. On the mobility of carbon-supported platinum nanoparticles towards unveiling cathode degradation in water electrolysis

    Science.gov (United States)

    Paciok, Paul; Schalenbach, Maximilian; Carmo, Marcelo; Stolten, Detlef

    2017-10-01

    This study investigates the influence of the hydrogen evolution reaction (HER) overpotential on the mobility of carbon-supported platinum particles. The migration of the platinum over the carbon support was analyzed by means of identical location transmission electron microscopy (IL-TEM). While at potentials of 0.1 and 0 V vs. reversible hydrogen electrode (RHE), no changes to the Pt/C material were observed. With a decrease of the overpotential to -0.1 V vs. RHE, an increase in the quantity of migrating platinum particles took place. At -0.2 V vs. RHE, a further rise in the particle migration was observed. The effect of the overpotential on the migration was explained by a higher hydrogen generation rate, the formation of a hydrogen monolayer on the platinum and the resulting changes of the platinum support distance. The mechanisms revealed in this study could describe a relevant source of degradation of PEM water electrolyzers.

  12. PLATINUM: a web tool for analysis of hydrophobic/hydrophilic organization of biomolecular complexes.

    Science.gov (United States)

    Pyrkov, Timothy V; Chugunov, Anton O; Krylov, Nikolay A; Nolde, Dmitry E; Efremov, Roman G

    2009-05-01

    The PLATINUM (Protein-Ligand ATtractions Investigation NUMerically) web service is designed for analysis and visualization of hydrophobic/hydrophilic properties of biomolecules supplied as 3D-structures. Furthermore, PLATINUM provides a number of tools for quantitative characterization of the hydrophobic/hydrophilic match in biomolecular complexes e.g. in docking poses. These complement standard scoring functions. The calculations are based on the concept of empirical Molecular Hydrophobicity Potential (MHP). The PLATINUM web tool as well as detailed documentation and tutorial are available free of charge for academic users at http://model.nmr.ru/platinum/. PLATINUM requires Java 5 or higher and Adobe Flash Player 9. Supplementary data are available at Bioinformatics online.

  13. Platinum-polyaniline-modified carbon fiber electrode for the electrooxidation of methanol

    Institute of Scientific and Technical Information of China (English)

    WU Kezhong; MENG Xu; WANG Xindong; LI Jingling

    2005-01-01

    Platinum was electrodeposited onto a polyaniline-modified carbon fiber electrode by the cyclic voltammetric method in sulfuric acid, which may enable an increase in the level of platinum u tilization currently achieved in electrocatalyric systems. This electrode preparation consists of a two-step procedure: first electropolymerization of aniline onto carbon fiber and then electrodeposition of platinum. The catalytic activity of the platinum-polyaniline-modified carbon fiber electrode (Pt/PAni/C) was compared with that of a bare carbon fiber electrode (Pt/C) by the oxidation of methanol. The maximum oxidation current of methanol on Pt/PAni/C is 50.7 mA.cm-2, which is 6.7 times higher than 7.6 mA.cm-2 on the Pt/C.Scanning electron microscopy was used to investigate the dispersion of the platinum particles of about 0.4 μm.

  14. Bulk synthesis of nanoporous palladium and platinum powders

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, David B; Fares, Stephen J; Tran, Kim L; Langham, Mary E

    2014-04-15

    Disclosed is a method for providing nanoporous palladium and platinum powders. These materials were synthesized on milligram to gram scales by chemical reduction of tetrahalo-complexes with ascorbate in a concentrated aqueous surfactant at temperatures between -20.degree. C. and 30.degree. C. The prepared particles have diameters of approximately 50 nm, wherein each particle is perforated by pores having diameters of approximately 3 nm, as determined by electron tomography. These materials are of potential value for hydrogen and electrical charge storage applications.

  15. Effect of Platinum Group Metal Doping in Magnesium Diboride Wires

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude; Alexiou, Aikaterini; Namazkar, Shahla

    2016-01-01

    The effect of some platinum group metals(PGM = Rh, Pd, and Pt) on the microstructure and critical current density of Cu/Nb-sheathed MgB2 wires has been studied using Mg1-x PGMxB2 powders with low doping levels. It was found that Pt and Pd do not enter the MgB2 lattice and have only limited....... The results are discussed in comparison with previous investigations using other transition metals for doping on the Mg site....

  16. Pulse Voltammetry in Single Cells Using Platinum Microelectrodes

    Science.gov (United States)

    1991-11-22

    ring electrodes [18) in a solution of 1.OxlO’ M H2PtCl6 and 0.5 M H2SO4 and reducing platinum at 0.0 V vs SSCE for a desired deposition time. Cyclic ...E. and the range for Ed in multiple pulse voltammetry can be chosen from examination of voltammograms obtained by cyclic voltammetry or lin-ir sweep... voltametry [3,13]. As pointed out by Sinru et al. [14) the potential and time of each pulse has a direct effect on the nature of the voltammetry

  17. Stability and phase transfer of catalytically active platinum nanoparticle suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Sriram, Indira; Curtin, Alexandra E.; Chiaramonti, Ann N.; Cuchiaro, J. Hunter; Weidner, Andrew R.; Tingley, Tegan M.; Greenlee, Lauren F.; Jeerage, Kavita M., E-mail: jeerage@boulder.nist.gov [National Instrument of Standards and Technology, Applied Chemicals and Materials Division (United States)

    2015-05-15

    In this work, we present a robust synthesis protocol for platinum nanoparticles that yields a monomodal dispersion of particles that are approximately 100 nm in diameter. We determine that these particles are actually agglomerates of much smaller particles, creating a “raspberry” morphology. We demonstrate that these agglomerates are stable at room temperature for at least 8 weeks by dynamic light scattering. Furthermore, we demonstrate consistent electrocatalytic activity for methanol oxidation. Finally, we quantitatively explore the relationship between dispersion solvent and particle agglomeration; specifically, particles are found to agglomerate abruptly as solvent polarity decreases.

  18. Synthesis and polarized photoluminescence of novel phosphorescent cyclometalated platinum dimer

    Institute of Scientific and Technical Information of China (English)

    Shi Ping Jiang; Kai Jun Luo; Ying Han Wang; Xin Wang; Ying Jiang; Yan Yan Wei

    2011-01-01

    A novel phosphorescent cyclometalated platinum dimer with bis-[2-(p-dodecyloxyphenyl) pyridyl]-hexane-l,6-diol as ligand and 1,3-( 1-n-hexyl,3-n-heptadecyl) diketone as ancillary ligand was synthesized. The chemical structure and liquid crystal property of the dimer were characterized by 1H NMR, ESI-MS, polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). The aligned film of title compound on the rubbed polyimide film is intensely emissive at room temperature with emission maximum at 516 nm. The luminescence dichroic ratio (I∥/ IL) at 516 nm is 3.1.

  19. Bulk synthesis of nanoporous palladium and platinum powders

    Science.gov (United States)

    Robinson, David B [Fremont, CA; Fares, Stephen J [Pleasanton, CA; Tran, Kim L [Livermore, CA; Langham, Mary E [Pleasanton, CA

    2012-04-17

    Disclosed is a method for providing nanoporous palladium and platinum powders. These materials were synthesized on milligram to gram scales by chemical reduction of tetrahalo-complexes with ascorbate in a concentrated aqueous surfactant at temperatures between -20.degree. C. and 30.degree. C. The prepared particles have diameters of approximately 50 nm, wherein each particle is perforated by pores having diameters of approximately 3 nm, as determined by electron tomography. These materials are of potential value for hydrogen and electrical charge storage applications.

  20. Biological assessment of the effects of construction and operation of adepleted uranium hexafluoride conversion facility at the Portsmouth, Ohio,site.

    Energy Technology Data Exchange (ETDEWEB)

    Van Lonkhuyzen, R.

    2005-09-09

    The U.S. Department of Energy (DOE) Depleted Uranium Hexafluoride (DUF{sub 6}) Management Program evaluated alternatives for managing its inventory of DUF{sub 6} and issued the ''Programmatic Environmental Impact Statement for Alternative Strategies for the Long-Term Management and Use of Depleted Uranium Hexafluoride'' (DUF{sub 6} PEIS) in April 1999 (DOE 1999). The DUF{sub 6} inventory is stored in cylinders at three DOE sites: Paducah, Kentucky; Portsmouth, Ohio; and East Tennessee Technology Park (ETTP), near Oak Ridge, Tennessee. In the Record of Decision for the DUF{sub 6} PEIS, DOE stated its decision to promptly convert the DUF{sub 6} inventory to a more stable chemical form. Subsequently, the U.S. Congress passed, and the President signed, the ''2002 Supplemental Appropriations Act for Further Recovery from and Response to Terrorist Attacks on the United States'' (Public Law No. 107-206). This law stipulated in part that, within 30 days of enactment, DOE must award a contract for the design, construction, and operation of a DUF{sub 6} conversion plant at the Department's Paducah, Kentucky, and Portsmouth, Ohio, sites, and for the shipment of DUF{sub 6} cylinders stored at ETTP to the Portsmouth site for conversion. This biological assessment (BA) has been prepared by DOE, pursuant to the National Environmental Policy Act of 1969 and the Endangered Species Act of 1974, to evaluate potential impacts to federally listed species from the construction and operation of a conversion facility at the DOE Portsmouth site. The Indiana bat is known to occur in the area of the Portsmouth site and may potentially occur on the site during spring or summer. Evaluations of the Portsmouth site indicated that most of the site was found to have poor summer habitat for the Indiana bat because of the small size, isolation, and insufficient maturity of the few woodlands on the site. Potential summer habitat for the Indiana bat was

  1. Targeting Notch, a key pathway for ovarian cancer stem cells, sensitizes tumors to platinum therapy.

    Science.gov (United States)

    McAuliffe, Shannon M; Morgan, Stefanie L; Wyant, Gregory A; Tran, Lieu T; Muto, Katherine W; Chen, Yu Sarah; Chin, Kenneth T; Partridge, Justin C; Poole, Barish B; Cheng, Kuang-Hung; Daggett, John; Cullen, Kristen; Kantoff, Emily; Hasselbatt, Kathleen; Berkowitz, Julia; Muto, Michael G; Berkowitz, Ross S; Aster, Jon C; Matulonis, Ursula A; Dinulescu, Daniela M

    2012-10-23

    Chemoresistance to platinum therapy is a major obstacle that needs to be overcome in the treatment of ovarian cancer patients. The high rates and patterns of therapeutic failure seen in patients are consistent with a steady accumulation of drug-resistant cancer stem cells (CSCs). This study demonstrates that the Notch signaling pathway and Notch3 in particular are critical for the regulation of CSCs and tumor resistance to platinum. We show that Notch3 overexpression in tumor cells results in expansion of CSCs and increased platinum chemoresistance. In contrast, γ-secretase inhibitor (GSI), a Notch pathway inhibitor, depletes CSCs and increases tumor sensitivity to platinum. Similarly, a Notch3 siRNA knockdown increases the response to platinum therapy, further demonstrating that modulation of tumor chemosensitivity by GSI is Notch specific. Most importantly, the cisplatin/GSI combination is the only treatment that effectively eliminates both CSCs and the bulk of tumor cells, indicating that a dual combination targeting both populations is needed for tumor eradication. In addition, we found that the cisplatin/GSI combination therapy has a synergistic cytotoxic effect in Notch-dependent tumor cells by enhancing the DNA-damage response, G(2)/M cell-cycle arrest, and apoptosis. Based on these results, we conclude that targeting the Notch pathway could significantly increase tumor sensitivity to platinum therapy. Our study suggests important clinical applications for targeting Notch as part of novel treatment strategies upon diagnosis of ovarian cancer and at recurrence. Both platinum-resistant and platinum-sensitive relapses may benefit from such an approach as clinical data suggest that all relapses after platinum therapy are increasingly platinum resistant.

  2. Numerical Investigation into CO Emission, O Depletion, and Thermal Decomposition in a Reacting Slab

    Directory of Open Access Journals (Sweden)

    O. D. Makinde

    2011-01-01

    Full Text Available The emission of carbon dioxide (CO2 is closely associated with oxygen (O2 depletion, and thermal decomposition in a reacting stockpile of combustible materials like fossil fuels (e.g., coal, oil, and natural gas. Moreover, it is understood that proper assessment of the emission levels provides a crucial reference point for other assessment tools like climate change indicators and mitigation strategies. In this paper, a nonlinear mathematical model for estimating the CO2 emission, O2 depletion, and thermal stability of a reacting slab is presented and tackled numerically using a semi-implicit finite-difference scheme. It is assumed that the slab surface is subjected to a symmetrical convective heat and mass exchange with the ambient. Both numerical and graphical results are presented and discussed quantitatively with respect to various parameters embedded in the problem.

  3. Reacting gas mixtures in the state-to-state approach: The chemical reaction rates

    Energy Technology Data Exchange (ETDEWEB)

    Kustova, Elena V. [Department of Mathematics and Mechanics, Saint Petersburg State University, 198504 Universitetskiy pr., 28, Saint Petersburg (Russian Federation); Kremer, Gilberto M. [Departamento de Física, Universidade Federal do Paraná, Caixa Postal 19044, 81531-980 Curitiba (Brazil)

    2014-12-09

    In this work chemically reacting mixtures of viscous flows are analyzed within the framework of Boltzmann equation. By applying a modified Chapman-Enskog method to the system of Boltzmann equations general expressions for the rates of chemical reactions and vibrational energy transitions are determined as functions of two thermodynamic forces: the velocity divergence and the affinity. As an application chemically reacting mixtures of N{sub 2} across a shock wave are studied, where the first lowest vibrational states are taken into account. Here we consider only the contributions from the first four single quantum vibrational-translational energy transitions. It is shown that the contribution to the chemical reaction rate related to the affinity is much larger than that of the velocity divergence.

  4. Reacting gas mixtures in the state-to-state approach: The chemical reaction rates

    Science.gov (United States)

    Kustova, Elena V.; Kremer, Gilberto M.

    2014-12-01

    In this work chemically reacting mixtures of viscous flows are analyzed within the framework of Boltzmann equation. By applying a modified Chapman-Enskog method to the system of Boltzmann equations general expressions for the rates of chemical reactions and vibrational energy transitions are determined as functions of two thermodynamic forces: the velocity divergence and the affinity. As an application chemically reacting mixtures of N2 across a shock wave are studied, where the first lowest vibrational states are taken into account. Here we consider only the contributions from the first four single quantum vibrational-translational energy transitions. It is shown that the contribution to the chemical reaction rate related to the affinity is much larger than that of the velocity divergence.

  5. Novel methodology to perform sulfur hexafluoride (SF6)-based multiple-breath wash-in and washout in infants using current commercially available equipment.

    Science.gov (United States)

    Gustafsson, P M; Robinson, P D; Lindblad, A; Oberli, D

    2016-11-01

    Multiple-breath inert gas washout (MBW) is ideally suited for early detection and monitoring of serious lung disease, such as cystic fibrosis, in infants and young children. Validated commercial options for the MBW technique are limited, and suitability of nitrogen (N2)-based MBW is of concern given the detrimental effect of exposure to pure O2 on infant breathing pattern. We propose novel methodology using commercially available N2 MBW equipment to facilitate 4% sulfur hexafluoride (SF6) multiple-breath inert gas wash-in and washout suitable for the infant age range. CO2, O2, and sidestream molar mass sensor signals were used to accurately calculate SF6 concentrations. An improved dynamic method for synchronization of gas and respiratory flow was developed to take into account variations in sidestream sample flow during MBW measurement. In vitro validation of triplicate functional residual capacity (FRC) assessments was undertaken under dry ambient conditions using lung models ranging from 90 to 267 ml, with tidal volumes of 28-79 ml, and respiratory rates 20-60 per minute. The relative mean (SD, 95% confidence interval) error of triplicate FRC determinations by washout was -0.26 (1.84, -3.86 to +3.35)% and by wash-in was 0.57 (2.66, -4.66 to +5.79)%. The standard deviations [mean (SD)] of percentage error among FRC triplicates were 1.40 (1.14) and 1.38 (1.32) for washout and wash-in, respectively. The novel methodology presented achieved FRC accuracy as outlined by current MBW consensus recommendations (95% of measurements within 5% accuracy). Further clinical evaluation is required, but this new technique, using existing commercially available equipment, has exciting potential for research and clinical use.

  6. Chlorofluorocarbons, Sulfur Hexafluoride, and Dissolved Permanent Gases in Ground Water from Selected Sites In and Near the Idaho National Engineering and Environmental Laboratory, Idaho, 1994 - 1997

    Energy Technology Data Exchange (ETDEWEB)

    Busenberg, E.; Plummer, L.N.; Bartholomay, R.C.; Wayland, J.E.

    1998-08-01

    From July 1994 through May 1997, the U.S. Geological Survey, in cooperations with the Department of Energy, sampled 86 wells completed in the Snake River Plain aquifer at and near the Idaho National Engineering and Environmental Laboratory (INEEL). The wells were sampled for a variety of constituents including one- and two-carbon halocarbons. Concentrations of dichlorodifluoromethane (CFC-12), trichlorofluoromethane (CFC-11), and trichlorotrifluororoethane (CFC-113) were determined. The data will be used to evaluate the ages of ground waters at INEEL. The ages of the ground water will be used to determine recharge rates, residence time, and travel time of water in the Snake River Plain aquifer in and near INEEL. The chromatograms of 139 ground waters are presented showing a large number of halomethanes, haloethanes, and haloethenes present in the ground waters underlying the INEEL. The chromatograms can be used to qualitatively evaluate a large number of contaminants at parts per trillion to parts per billion concentrations. The data can be used to study temporal and spatial distribution of contaminants in the Snake River Plain aquifer. Representative compressed chromatograms for all ground waters sampled in this study are available on two 3.5-inch high density computer disks. The data and the program required to decompress the data can be obtained from the U.S. Geological Survey office at Idaho Falls, Idaho. Sulfur hexafluoride (SF6) concentrations were measured in selected wells to determine the feasibility of using this environmental tracer as an age dating tool of ground water. Concentrations of dissolved nitrogen, argon, carbon dioxide, oxygen, and methane were measured in 79 ground waters. Concentrations of dissolved permanent gases are tabulated and will be used to evaluate the temperature of recharge of ground water in and near the INEEL.

  7. A Reference Equation of State for the Thermodynamic Properties of Sulfur Hexafluoride (SF6) for Temperatures from the Melting Line to 625 K and Pressures up to 150 MPa

    Science.gov (United States)

    Guder, C.; Wagner, W.

    2009-03-01

    A new equation of state for the thermodynamic properties of the fluid phase of sulfur hexafluoride (SF6) in the form of a fundamental equation explicit in the Helmholtz energy is presented. The functional form consists of a part describing the ideal-gas state and the residual part as the difference between the real-fluid and the ideal-gas behavior. The residual part was developed using state-of-the-art linear and nonlinear optimization algorithms. It contains 36 coefficients, which were fitted to selected data for the thermal and caloric properties of sulfur hexafluoride in the single-phase region and on the vapor-liquid phase boundary. Especially for the thermal properties in the critical region, a very extensive and high-precision data set was available. In this work, information on the experimental data for the thermodynamic properties and all details of the new equation are presented. The new equation of state describes the pρT surface of sulfur hexafluoride with an uncertainty in density of less than 0.02%-0.03% from the melting line up to temperatures of 500K and pressures of 30MPa. In the critical region, including the immediate vicinity of the critical point, the uncertainty in pressure is less than 0.01%. Reliable data sets of other thermodynamic properties are reproduced within their experimental uncertainties. The primary data, to which the equation was fitted, cover the fluid region from the melting line to temperatures of 625K and pressures up to 150MPa. Beyond this range, the equation can be extrapolated with a physically reasonable behavior up to very high temperatures and pressures. In addition to the equation of state, independent equations for the vapor pressure, the saturated-liquid and saturated-vapor densities, the melting pressure, and the sublimation pressure are given. Tables of thermodynamic properties calculated from the new equation of state are listed in the Appendix.

  8. Reacting to anticipations : energy crises and energy policy in the 1970s ; an introduction

    OpenAIRE

    Bösch, Frank; Graf, Rüdiger

    2014-01-01

    Changes in the energy sector cannot be sufficiently described as reactions to past and present energy problems. Rather, politicians and companies alike always react to the anticipation of future challenges. Sharing this assumption, the articles in this HSR Special Issue reexamine the energy crises of the 1970s. Their assessments broaden the temporal and spatial scope of analysis and integrate various energy resources into the picture, while examining how to situate the first...

  9. A seizure response dog: video recording of reacting behaviour during repetitive prolonged seizures.

    Science.gov (United States)

    Di Vito, Lidia; Naldi, Ilaria; Mostacci, Barbara; Licchetta, Laura; Bisulli, Francesca; Tinuper, Paolo

    2010-06-01

    Seizure response and alerting behaviour may spontaneously develop in dogs living with children or adults with epilepsy. Some dogs can also be reliably trained to respond and anticipate seizures. We describe the case of a dog, not previously trained for assistance work, showing complex seizure response behaviour. This is the first release of a home video recording of a dog reacting to its owner's seizure.

  10. Competitor's marketing : How banks acquire and react to knowledge about their competitor's marketing.

    OpenAIRE

    Puelma, Rodrigo; Persson, Annika

    2008-01-01

    Abstract   Introduction The way banks compete has changed dramatically during recent years, mostly because of international trends such as advances in information technology, globalisation and deregulations. This has made competition harsher meaning that survival and success requires knowledge about the competitors and understanding about the way they act and react. Within marketing there is a need to identify suitable strategies to acquire knowledge about competitor’s marketing and methods t...

  11. (U) Design Considerations for Obtaining Deep Release in Reacted Epon 828

    Energy Technology Data Exchange (ETDEWEB)

    Fredenburg, David A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lang, John Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dattelbaum, Dana Mcgraw [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bennett, Langdon Stanford [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-16

    Our document summarizes results from one-dimensional calculations performed to investigate the release behavior of reacted Epon 828. Two design goals were set, (1) the product phase had to be achieved upon the initial shock loading, and (2) a deep release state could be achieved. Both transmission and front surface impact geometry were investigated. Moreover, the two design criteria were met with the front surface impact design employing a modi ed projectile.

  12. Recent progress of laser metrology in chemically reacting flows at onera

    Science.gov (United States)

    Mohamed, A.; Dorval, N.; Vilmart, G.; Orain, M.; George, R.; Scherman, M.; Nafa, M.; Bresson, A.; Attal-Tretout, B.; Lefebvre, M.

    2017-06-01

    This paper presents some of the development actions performed these last years at ONERA using laser spectroscopic techniques to probe chemically reacting flows. Techniques like laser absorption, laser induced fluorescence (LIF), and Raman scattering will be described with focus on present drawbacks as well as expectations from new laser technologies (Interband Cascade Lasers (ICL) diodes, Optical Parametrical Oscillators (OPO), frequency comb, and femto/picosecond lasers) before showing some results of recent applications in ground facilities.

  13. Phased Array Ultrasound: Initial Development of PAUT Inspection of Self-Reacting Friction Stir Welds

    Science.gov (United States)

    Rairigh, Ryan

    2008-01-01

    This slide presentation reviews the development of Phased Array Ultrasound (PAUT) as a non-destructive examination method for Self Reacting Friction Stir Welds (SR-FSW). PAUT is the only NDE method which has been shown to detect detrimental levels of Residual Oxide Defect (ROD), which can result in significant decrease in weld strength. The presentation reviews the PAUT process, and shows the results in comparison with x-ray radiography.

  14. Enhancement effect of pre-reacted glass on strength of glass-ionomer cement.

    Science.gov (United States)

    Monmaturapoj, Naruporn; Soodsawang, Wiwaporn; Tanodekaew, Siriporn

    2012-02-03

    In this paper, we report on the enhanced strength of glass ionomer cement (GIC) by using the process of pre acid-base reaction and spray drying in glass preparation. The pre acid-base reaction was induced by prior mixing of the glass powder with poly(alkenoic acid). The weight ratios of glass powder to poly(alkenoic acid) were varied to investigate the extent of the pre acid-base reaction of the glass. The effect of the spray drying process which produced spherical glass particles on cement strength was also studied and discussed. The results show that adding 2%-wt of poly(alkenoic acid) liquid in the pre-reacted step improved cement strength. GICs prepared using a mixture of pre-reacted glass with both spherical and irregular powders at 60:40 by weight exhibited the highest compressive strength at 138.64±7.73 MPa. It was concluded that glass ionomer cements containing pre-reacted glass with mixed glass morphology using both spherical and irregular forms are promising as restorative dental materials with improved mechanical properties and handling characteristics.

  15. Small molecular, macromolecular, and cellular chloramines react with thiocyanate to give the human defense factor hypothiocyanite.

    Science.gov (United States)

    Xulu, Bheki A; Ashby, Michael T

    2010-03-09

    Thiocyanate reacts noncatalytically with myeloperoxidase-derived HOCl to produce hypothiocyanite (OSCN(-)), thereby potentially limiting the propensity of HOCl to inflict host tissue damage that can lead to inflammatory diseases. However, the efficiency with which SCN(-) captures HOCl in vivo depends on the concentration of SCN(-) relative to other chemical targets. In blood plasma, where the concentration of SCN(-) is relatively low, proteins may be the principal initial targets of HOCl, and chloramines are a significant product. Chloramines eventually decompose to irreversibly damage proteins. In the present study, we demonstrate that SCN(-) reacts efficiently with chloramines in small molecules, in proteins, and in Escherichia coli cells to give OSCN(-) and the parent amine. Remarkably, OSCN(-) reacts faster than SCN(-) with chloramines. These reactions of SCN(-) and OSCN(-) with chloramines may repair some of the damage that is inflicted on protein amines by HOCl. Our observations are further evidence for the importance of secondary reactions during the redox cascades that are associated with oxidative stress by hypohalous acids.

  16. Small Molecular, Macromolecular and Cellular Chloramines React with Thiocyanate to Give the Human Defense Factor Hypothiocyanite†

    Science.gov (United States)

    Xulu, Bheki A.; Ashby, Michael T.

    2010-01-01

    Thiocyanate reacts non-catalytically with myeloperoxidase-derived HOCl to produce hypothiocyanite (OSCN−), thereby potentially limiting the propensity of HOCl to inflict host tissue damage that can lead to inflammatory diseases. However, the efficiency with which SCN− captures HOCl in vivo depends on the concentration of SCN− relative to other chemical targets. In blood plasma, where the concentration of SCN− is relatively low, proteins may be the principal initial targets of HOCl, and chloramines are a significant product. Chloramines eventually decompose to irreversibly damage proteins. In the present study, we demonstrate that SCN− reacts efficiently with chloramines in small molecules, in proteins, and in Escherichia coli cells to give OSCN− and the parent amine. Remarkably, OSCN− reacts faster than SCN− with chloramines. These reactions of SCN− and OSCN− with chloramines may repair some of the damage that is inflicted on protein amines by HOCl. Our observations are further evidence for the importance of secondary reactions during the redox cascades that are associated with oxidative stress by hypohalous acids. PMID:20085320

  17. ReactPRED: a tool to predict and analyze biochemical reactions.

    Science.gov (United States)

    Sivakumar, Tadi Venkata; Giri, Varun; Park, Jin Hwan; Kim, Tae Yong; Bhaduri, Anirban

    2016-11-15

    Biochemical pathways engineering is often used to synthesize or degrade target chemicals. In silico screening of the biochemical transformation space allows predicting feasible reactions, constituting these pathways. Current enabling tools are customized to predict reactions based on pre-defined biochemical transformations or reaction rule sets. Reaction rule sets are usually curated manually and tailored to specific applications. They are not exhaustive. In addition, current systems are incapable of regulating and refining data with an aim to tune specificity and sensitivity. A robust and flexible tool that allows automated reaction rule set creation along with regulated pathway prediction and analyses is a need. ReactPRED aims to address the same. ReactPRED is an open source flexible and customizable tool enabling users to predict biochemical reactions and pathways. The tool allows automated reaction rule creation from a user defined reaction set. Additionally, reaction rule degree and rule tolerance features allow refinement of predicted data. It is available as a flexible graphical user interface and a console application. ReactPRED is available at: https://sourceforge.net/projects/reactpred/ CONTACT: anirban.b@samsung.com or ty76.kim@samsung.comSupplementary information: Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  18. Characterization of Aeromonas trota strains that cross-react with Vibrio cholerae O139 Bengal.

    Science.gov (United States)

    Albert, M J; Ansaruzzaman, M; Shimada, T; Rahman, A; Bhuiyan, N A; Nahar, S; Qadri, F; Islam, M S

    1995-12-01

    It has previously been shown that Vibrio cholerae O139 Bengal shares antigens with V. cholerae serogroups O22 and O155. We detected six surface water isolates of Aeromonas trota that agglutinated in polyclonal antisera to V. cholerae O139 and V. cholerae O22 but not in antiserum to V. cholerae O155. On the basis of agglutinin-absorption studies, the antigenic relationship between the cross-reacting bacteria were found to be in an a,b-a,c fashion, where a is the common antigenic epitope and b and c are unique epitopes. The antigen sharing between A. trota strains and V. cholerae O139 was confirmed in immunoblot studies. However, A. trota strains did not react with two monoclonal antibodies specific for V. cholerae O139 and, consequently, tested negative in the Bengal SMART rapid diagnostic test for V. cholerae O139 which uses one of the monoclonal antibodies. A polyclonal antiserum to a cross-reacting A. trota strain cross-protected infant mice against cholera on challenge with virulent V. cholerae O139. All A. trota strains were cytotoxic for HeLa cells, positive for adherence to HEp-2 cells, and weakly invasive for HEp-2 cells; one strain was heat-stable toxin positive in the suckling mouse assay; however, all strains were negative for cholera toxin-like enterotoxin. Studies on bacteria that share somatic antigen with V. cholerae O139 may shed further light on the genesis of V. cholerae O139.

  19. Cytotoxicity of platinum(IV) and platinum(II) complexes containing 1R,2R-cyclohexanediamine as a ligand.

    Science.gov (United States)

    Yamashita, T; Hirose, J; Noji, M; Saito, R; Tomida, H; Kidani, Y

    1993-10-01

    Several Pt(IV) and Pt(II) complexes containing 1R,2R-cyclohexanediamine (1R,2R-dach) as a carrier ligand were synthesized. The cytotoxicities and the uptake of the platinum complexes by leukemia L1210 cells were compared in order to study the correlation between their structures and cytotoxicities. [Pt(II)Cl2(1R,2R-dach)], [(Pt(II)(oxalato)(1R,2R-dach)], and [Pt(II)(malonato)(1R,2R-dach)], which have excellent anticancer properties, exhibited very high cytotoxicities and were easily taken up by leukemia L1210 cells. [Pt(IV)Cl4(1R,2R-dach)], trans(Cl)-[Pt(IV)Cl2(oxalato)(1R,2R-dach)], and trans(Cl)-[Pt(IV)Cl2(malonato)(1R,2R-dach)] also had high cytotoxicities. After a short incubation time, the uptake of [Pt(II)Cl2(1R,2R-dach)], [Pt(II)(oxalato)(1R,2R-dach)], and [Pt(II)(malonato)(1R,2R-dach)] by leukemia L1210 cells were respectively very similar to those of [Pt(IV)Cl4(1R,2R-dach)], trans(Cl)-[Pt(IV)Cl2(oxalato)(1R,2R-dach)], and trans(Cl)-[Pt(IV)Cl2(malonato)(1R,2R-dach)]. In addition, trans(OH)-[Pt(IV)(OH)2Y2(1R,2R-dach)] (Y2: oxalato or malonato) did not exhibit cytotoxicity towards leukemia L1210 cells, whereas trans(Cl)-[Pt(IV)Cl2Y2(1R,2R-dach)] (Y2: oxalato or malonato) were highly cytotoxic. The accumulation of trans(OH)-[Pt(IV)(OH)2Y2(1R,2R-dach)] in leukemia L1210 cells was much lower than that of trans(Cl)-[Pt(IV)Cl2Y2(1R,2R-dach)]. Platinum(IV) complexes, in which leaving groups are replaced by hydroxide groups, have decreased cytotoxic activity, because the hydroxide groups of the platinum(IV) complex reduce the uptake of platinum by the cells. trans(OH),cis(Cl)-[Pt(IV)(OH)2Cl2(1R,2R-dach)], which has hydroxide and chloride groups, was easily incorporated into the cells and exhibited the high cytotoxic activity. This behavior indicates that the chloride group apparently overcomes the ameliorating effect of the hydroxide group.

  20. Isolated High-Purity Platinum Nanowire Growth via Field Emission from a Multi-Walled Carbon Nanotube

    Science.gov (United States)

    Yang, Zhan; Nakajima, Masahiro; Saito, Yahachi; Ode, Yasuhito; Fukuda, Toshio

    2011-03-01

    Isolated high-purity platinum nanowire growth was presented via field emission from the tip of a multi-walled carbon nanotube (MWCNT) with a precursor of cyclopentadienyl-trimethyl-platinum(IV) (CpPtMe3) inside a scanning electron microscope (SEM). A nanomanipulation system was used to adjust the gap between the anode (tungsten probe) and cathode (MWCNT) in order to control the nanowire growth length which achieved a platinum nanowire length of 1.18 µm. The chemical composition of the platinum nanowire analyzed by energy-dispersive X-ray spectroscopy (EDS) shows that the purity of the platinum in the nanowire reaches 94.9 wt %.

  1. Patterned Platinum Etching Studies in an Argon High Density Plasma

    Science.gov (United States)

    Delprat, Sébastien; Chaker, Mohamed; Margot, Joëlle; Pépin, Henri; Tan, Liang; Smy, Tom

    1998-10-01

    A high-density surface-wave Ar plasma operated in the low pressure regime is used to study pure physical etching characteristics of platinum thin films. The platinum samples are RF biased so as to obtain a maximum DC self-bias voltage of 150 V. The sputter-etching characteristics are investigated as a function of the magnetic field intensity, the self-bias voltage and the gas pressure. At 1 mtorr, the etch rate is found to be a unique linear function of both the self-bias voltage and the ion density, independently of the magnetic field intensity value. However, even though the ion density increases, the etch rate is found to decrease with increasing pressure. In the low pressure regime, etch rates as high as 2000 A/min are obtained with a good selectivity over resist. Without any optimization of the etching process, we were able to etch 0.5 micron Pt trenches, 0.6 micron thick yielding fence-free profiles and sidewall angles (75º) that already meets the present industrial requirements of NVRAM technology.

  2. Potentiometric titration of gold, platinum, and some other precious metals

    Energy Technology Data Exchange (ETDEWEB)

    Selig, W.S.

    1991-02-04

    Gold, platinum, and several other platinum metals can be determined by titration with cetylpyridinium chloride (CPC). CPC forms a precipitate with AuCl{sub 4}{sup {minus}} and PtCl{sub 6}{sup 2{minus}}. Differentiation of AuCl{sub 4{minus}} and PtCl{sub 6}{sup 2{minus}} with this titrant is not possible; however, their sum can be determined. Titration with tetraphenylarsonium chloride at pH 1 is selective for tetrachloroaurate, which thus can be determined in the presence of hexachloroplatinate. Hexachloroosmate(IV), tetrachloroplatinite(II), tetrachloropalladate(II), hexachloropalladate(IV), and hexachloroiridate(IV) can also be determined potentiometrically vs. CPC. The indicating electrode is prepared by coating a spectroscopic graphite rod with a solution of poly(vinyl chloride) (PVC) and dioctylphthalate (DOP) in tetrahydrofuran (THF). Gold in gold cyanide plating baths and in potassium aurocyanide can be determined by potentiometric titration vs standard silver nitrate, using a silver ion-selective indicating electrode. The monovalent gold need not be converted to the trivalent state with aqua regia, resulting in a considerable saving of time and effort. Free cyanide and aurocyanide can be titrated sequentially by this method. Chloride does not interfere and can, in fact, also be sequentially determined. 17 refs., 2 figs., 3 tabs.

  3. Palladium and platinum organochalcogenolates and their transformation into metal chalcogenides

    Indian Academy of Sciences (India)

    S Dey; S Narayan; A Singhal; V K Jain

    2000-06-01

    Platinum group metal chalcogenides find extensive applications in catalysis and in the electronic industry. To develop an efficient low temperature clean preparation of these materials, molecular routes have been explored. Thus the chemistry of mononuclear organochalcogenolates of the type [M(ER 1/4)2(PR3)2], binuclear benzylselenolates, [M2Cl2(∼-SeBz)2(PR3)2], allylpalladium complexes [Pd2(μ-ER)2(3-C4H7)2] and palladium/platinum sulphido/selenido-bridged complexes, [M2(μ-E)2L4] (M = Pd or Pt; E = S, Se or Te; L = tertiary phosphine ligand) has been investigated. All the complexes have been characterized by elemental analysis, NMR (1 H, 31P, 77Se, 195Pt) spectroscopy and in some cases by X-ray diffraction. The thermal behaviour of these complexes has been studied by TGA. The pyrolysis of allylpalladium complexes in refluxing xylene yields Pd4E as established by analysis and XRD patterns.

  4. Platinum-induced ototoxicity: a review of prevailing ototoxicity criteria.

    Science.gov (United States)

    Waissbluth, Sofia; Peleva, Emilia; Daniel, Sam J

    2017-03-01

    The antineoplastic agent's cisplatin and carboplatin are widely used as they are highly effective. Unfortunately, ototoxicity is a frequently encountered side effect of platinum-based chemotherapy. Clinically, patients generally develop a progressive, bilateral, and irreversible sensorineural hearing loss. With rising cancer survival rates, a greater proportion of patients are living with the side effects of their chemotherapy treatments. Consequently, the quality of life of cancer survivors has now become a major concern for clinicians. Various classification systems are currently available to grade side effects and provide a guideline for subsequent treatments. An extensive review of the literature revealed that a variety of criteria are used worldwide for grading platinum-induced hearing loss in children and adults, including the National Cancer Institute criteria, Brock's grading system, the American Speech-Hearing-Language Association criteria, the World Health Organization criteria, the Pediatric Oncology Group criteria, and the Muenster classification. Less commonly used criteria include the Chang classification, the Functional Hearing Loss scale, the HIT system (German Hirntumor study grading system), and most recently, the International Society of Pediatric Oncology Boston ototoxicity grading scale. The objective of this review is to evaluate the commonly used ototoxicity criteria and discuss their benefits and limitations.

  5. Synthesis and characterization of novel platinum acetylide oligomers

    Science.gov (United States)

    Cooper, Thomas M.; Krein, Douglas M.; Burke, Aaron R.; McLean, Daniel G.; Rogers-Haley, Joy E.; Slagle, Jonathan; Monahan, Jennifer; Urbas, Augustine

    2008-08-01

    To learn about excited state geometry in biphenyl-containing platinum acetylides, we synthesized a series of compounds that have biphenyl ligands. The ligands consisted of biphenyl(I), the hindered 2'-methyl biphenyl(III) and planar fluorenyl(IV) groups. We also synthesized a "half" complex(II) consisting of one ligand attached to the platinum atom. The optical properties of these compounds were measured by ground state absorption, phosphorescence, ultrafast transient absorption and nanosecond transient absorption spectroscopy. DFT calculations were performed to determine the ground state and triplet state geometries and the lowest triplet energy. TDDFT calculations were performed to determine singlet excited state energies. Compared to the reference compound I, ground state spectra show a blue shift in II and III and red shift in IV, showing the singlet energy is sensitive to conjugation and biphenyl twist angle. Comparison of the phosphorescence spectra of I and II shows the triplet exciton is confined to one ligand. The time behavior of the ultrafast excited state absorption spectrum of I shows a red shift within 1 ps from the initial spectrum. This behavior is not seen in IV. The different behavior suggests formation of the triplet state of I is accompanied by conversion from a non-planar to a planar conformation while IV retains a planar conformation.

  6. Formic Acid Electrooxidation by a Platinum Nanotubule Array Electrode

    Directory of Open Access Journals (Sweden)

    Eric Broaddus

    2013-01-01

    Full Text Available One-dimensional metallic nanostructures such as nanowires, rods, and tubes have drawn much attention for electrocatalytic applications due to potential advantages that include fewer diffusion impeding interfaces with polymeric binders, more facile pathways for electron transfer, and more effective exposure of active surface sites. 1D nanostructured electrodes have been fabricated using a variety of methods, typically showing improved current response which has been attributed to improved CO tolerance, enhanced surface activity, and/or improved transport characteristics. A template wetting approach was used to fabricate an array of platinum nanotubules which were examined electrochemically with regard to the electrooxidation of formic acid. Arrays of 100 and 200 nm nanotubules were compared to a traditional platinum black catalyst, all of which were found to have similar surface areas. Peak formic acid oxidation current was observed to be highest for the 100 nm nanotubule array, followed by the 200 nm array and the Pt black; however, CO tolerance of all electrodes was similar, as were the onset potentials of the oxidation and reduction peaks. The higher current response was attributed to enhanced mass transfer in the nanotubule electrodes, likely due to a combination of both the more open nanostructure as well as the lack of a polymeric binder in the catalyst layer.

  7. Polyaniline-functionalized carbon nanotube supported platinum catalysts.

    Science.gov (United States)

    He, Daping; Zeng, Chao; Xu, Cheng; Cheng, Niancai; Li, Huaiguang; Mu, Shichun; Pan, Mu

    2011-05-03

    Electrocatalytically active platinum (Pt) nanoparticles on a carbon nanotube (CNT) with enhanced nucleation and stability have been demonstrated through introduction of electron-conducting polyaniline (PANI) to bridge the Pt nanoparticles and CNT walls with the presence of platinum-nitride (Pt-N) bonding and π-π bonding. The Pt colloids were prepared through ethanol reduction under the protection of aniline, the CNT was dispersed well with the existence of aniline in the solution, and aniline was polymerized in the presence of a protonic acid (HCl) and an oxidant (NH(4)S(2)O(8)). The synthesized PANI is found to wrap around the CNT as a result of π-π bonding, and highly dispersed Pt nanoparticles are loaded onto the CNT with narrowly distributed particle sizes ranging from 2.0 to 4.0 nm due to the polymer stabilization and existence of Pt-N bonding. The Pt-PANI/CNT catalysts are electroactive and exhibit excellent electrochemical stability and therefore promise potential applications in proton exchange membrane fuel cells.

  8. Chemical Imaging of Platinum-Based Drugs and their Metabolites.

    Science.gov (United States)

    Liu, Xin; Hummon, Amanda B

    2016-12-05

    Platinum-based drugs (cisplatin, carboplatin, and oxaliplatin) are widely used therapeutic agents for cancer treatment. Even though the platinum (Pt)-drugs are routinely used clinically, a clear picture of their distribution within tumor tissues is lacking. The current methods to image the distribution of Pt drugs are limited and do not enable the discrimination of the drug from its metabolites. In this manuscript, we demonstrate a methodology that enables chemical imaging of a Pt drug and its metabolites simultaneously and specifically. Matrix-Assisted Laser Desorption/Ionization (MALDI) Mass Spectrometry Imaging (MSI) is combined with an on-tissue chemical derivatization using diethyldithiocarbamate (DDTC). DDTC abstracts the Pt atom to generate ionizable complexes that can be imaged by MALDI MSI. We demonstrate that Pt drugs and their metabolites can be specifically imaged. This approach was successfully applied to map the penetration and metabolism of oxaliplatin in hyperthermic intraperitoneal chemotherapy (HIPEC)-like treated 3D colorectal tumor mimics. The distribution of cisplatin and carboplatin was mapped in additional 3D tumor mimics. We demonstrate that the approach can also be used to image the distribution of copper ions in cells. This method has the potential to be used to evaluate the penetration and distribution of a wide range of compounds.

  9. Surface segregations in platinum-based alloy nanoparticles

    Science.gov (United States)

    Yamakawa, Shunsuke; Asahi, Ryoji; Koyama, Toshiyuki

    2014-04-01

    A phase-field model that describes the radial distributions of the ordered-disordered phase and surface segregation in a single-alloy nanoparticle is introduced to clarify the overall behavior of surface segregation of various Pt-based alloy nanoparticles. One of the obstacles to apply a platinum-transition metal alloy as a cathode electro-catalyst of a polymer electrolyte fuel cell is the need to ensure the retention of the designed surface composition in an alloy nanoparticle against the alloy combinations, a particle size, and heat treatment. From the results of calculations for CrPt, FePt, CoPt, NiPt, CuPt, PdPt, IrPt, and AuPt binary nanoparticles with diameters below 10 nm at 973.15 K, the compositional variation within a single particle was found to depend on the balance between the atomic interaction within particles and the surface free energy. In addition, the obtained specific steady-state composition of the surface varied significantly with alloy combination and particle diameter. Based on the general tendencies of a binary system to exhibit segregation, attempts to control the amount of platinum segregation on the surface using a ternary-alloy system were examined.

  10. Platinum-group elements: so many excellent properties

    Science.gov (United States)

    Zientek, Michael L.; Loferski, Patricia J.

    2014-01-01

    The platinum-group elements (PGE) include platinum, palladium, rhodium, ruthenium, iridium, and osmium. These metals have similar physical and chemical properties and occur together in nature. The properties of PGE, such as high melting points, corrosion resistance, and catalytic qualities, make them indispensable to many industrial applications. PGE are strategic and critical materials for many nations because they are essential for important industrial applications but are mined in a limited number of places and have no adequate substitutes. Exploration and mining companies have found approximately 104,000 metric tons of PGE (with minor gold) in mineral deposits around the world that could be developed. For PGE, almost all known production and resources are associated with three geologic features: the Bushveld Complex, a layered mafic-to-ultramafic intrusion in South Africa; the Great Dyke, a layered mafic-to-ultramafic intrusion in Zimbabwe; and sill-like intrusions associated with flood basalts in the Noril’sk-Talnakh area, Russia. To help predict where PGE supplies might be located, USGS scientists study how and where PGE resources are concentrated in the Earth's crust and use that knowledge to assess the likelihood that undiscovered PGE deposits may exist. Techniques used for assessing mineral resources were developed by the USGS to support the stewardship of Federal lands and evaluate mineral resource availability in a global context. The USGS also compiles statistics and information on the worldwide supply, demand, and flow of PGE. These data are all used to inform U.S. national policymakers.

  11. Developing Central Nervous System and Vulnerability to Platinum Compounds

    Directory of Open Access Journals (Sweden)

    G. Bernocchi

    2011-01-01

    Full Text Available Comparative studies on the effects of the platinum complexes in use or in clinical trials are carried out in order to discover differences in the neurotoxic potential and the reversibility of neurotoxicity. In this paper, we summarized the current literature on neurotoxicity and chemoresistance of cisplatin (cisPt and discussed our recent efforts on the interference of cisPt and a new platinum compound [Pt(O,O′-acac(γ-acac(DMS] (PtAcacDMS, with high specific reactivity with sulphur ligands instead of nucleobases as cisPt, on some crucial events of rat postnatal cerebellum development. The acute effects of drug treatments on cell proliferation and death in the external granular layer and granule cell migration and the late effects on the dendrite growth of Purkinje cells were evaluated. Together with the demonstrated antineoplastic effectiveness in vitro, compared with cisPt, data suggest a lower neurotoxicity of PtAcacDMS, in spite of its presence in the brain that involves considerations on the blood brain barrier permeability.

  12. Platinum nanoparticles: a promising material for future cancer therapy?

    Science.gov (United States)

    Porcel, Erika; Liehn, Samuel; Remita, Hynd; Usami, Noriko; Kobayashi, Katsumi; Furusawa, Yoshiya; Le Sech, Claude; Lacombe, Sandrine

    2010-02-26

    Recently, the use of gold nanoparticles as potential tumor selective radiosensitizers has been proposed as a breakthrough in radiotherapy. Experiments in living cells and in vivo have demonstrated the efficiency of the metal nanoparticles when combined with low energy x-ray radiations (below conventional 1 MeV Linac radiation). Further studies on DNA have been performed in order to better understand the fundamental processes of sensitization and to further improve the method. In this work, we propose a new strategy based on the combination of platinum nanoparticles with irradiation by fast ions effectively used in hadron therapy. It is observed in particular that nanoparticles enhance strongly lethal damage in DNA, with an efficiency factor close to 2 for double strand breaks. In order to disentangle the effect of the nano-design architecture, a comparison with the effects of dispersed metal atoms at the same concentration has been performed. It is thus shown that the sensitization in nanoparticles is enhanced due to auto-amplified electronic cascades inside the nanoparticles, which reinforces the energy deposition in the close vicinity of the metal. Finally, the combination of fast ion radiation (hadron therapy) with platinum nanoparticles should strongly improve cancer therapy protocols.

  13. Sulfur tolerant zeolite supported platinum catalysts for aromatics hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Bergem, Haakon

    1997-12-31

    The increased demand for transportation fuels at the expence of heavier fuel oil has forced the refinery industry to expand their conversion capacity with hydrotreating as one of the key processes. A shift towards more diesel powered vehicles along with tightening fuel regulations demanding cleaner fuels has lead to increasing interest in catalytic processes for the manufacturing of such environmentally acceptable fuels. This provides the motivation for this thesis. Its main objective was to study possible catalysts active for desulfurization, hydrogenation, and ring-opening of aromatics all in the presence of sulfur. A close examination of the physical properties and kinetical behaviour of the chosen catalysts has been performed. A high pressure reactor setup was designed and built for activity measurements. Zeolite supported platinum catalysts were prepared and both the metal and acid functions were characterized utilizing various experimental techniques. Hydrogenation of toluene was used as a model reaction and the effect of sulfur adsorption on the activity and kinetic behaviour of the catalysts was investigated. The catalyst samples showed hydrogenation activities comparable to a commercial Pt/Al2O3 catalyst. There were no clear differences in the effect of the various sulfur compounds studied. Platinum supported on zeolite Y gave considerably more sulfur tolerant catalysts compared to Al2O3 as support. 155 refs., 58 figs., 36 tabs.

  14. Novel compliant electrodes based on platinum salt reduction

    Science.gov (United States)

    Delille, Remi; Urdaneta, Mario; Hsieh, Kuangwen; Smela, Elisabeth

    2006-03-01

    A compliant electrode material is presented that was inspired by the electroding process used to manufacture ionic polymer-metal composites (IPMCs). However, instead of an ion-exchange membrane, a UV-curable acrylated urethane elastomer is employed. The electrode material consists of the UV-curable elastomer (Loctite 3108) loaded with tetraammineplatinum(II) chloride salt particles through physical mixing and homogenization. The composite material is made conductive by immersion in a reducing agent, sodium borohydride, which reduces the salt to platinum metal on the surface of the elastomer film. Because the noble metal is mixed into the elastomer precursor as a salt, the amount of UV light absorbed by the precursor is not significantly reduced, and the composite loses little photopatternability. As a result meso-scale electrodes of varying geometries can be formed by exposing the precursor/salt mixture through a mask. The materials are mechanically and electrically characterized. The percolation threshold of the composite is estimated to be 9 vol. % platinum salt, above which the compliant electrode material exhibits a maximum conductivity of 1 S/cm. The composite maintains its electrical conductivity under axial tensile strains of up to 40%.

  15. Experimental investigation of a reacting transverse jet in a high pressure oscillating vitiated crossflow

    Science.gov (United States)

    Fugger, Christopher A.

    Staged combustion is one design approach in a gas turbine engine to reduce pollutant emission levels. In axially staged combustion, portions of the air and fuel are injected downstream of a lean premixed low NOx primary combustion zone. The gas residence time at elevated temperatures is decreased resulting in lower thermal NOx, and the reduced oxygen and high temperature vitiated primary zone flow further help to reduce pollutant emissions and quickly complete combustion. One implementation of axially staged combustion is transverse fuel jet injection. An important consideration for staged combustion systems, though, is how the primary and secondary combustion zones can couple through the acoustic resonances of the chamber. These couplings can lead to additional source terms that pump energy into the resonant acoustic field and help sustain the high-amplitude combustor pressure oscillations. An understanding of these couplings is important so that it may be possible to design a secondary combustion system that provides inherent damping to the combustor system. To systematically characterize the coupling of a reacting jet in unsteady crossflow in detail, the effects of an an unsteady pressure flowfield and an unsteady velocity flowfield are separately investigated. An optically accessible resonant combustion chamber was designed and built as part of this work to generate a standing wave unsteady vitiated crossflow at a chamber pressure of 0.9 MPa. The location of transverse jet injection corresponds to one of two locations, where one location is the pressure node and the other location the pressure anti-node of the resonant chamber acoustic mode. The injection location is optically accessible, and the dynamic interactions between the transverse jet flow and the 1st and 2nd axial combustor modes are measured using 10 kHz OH-PLIF and 2D PIV. This document analyzes five test cases: two non-reacting jets and three reacting jets. All cases correspond to jet injection

  16. Evolving concepts in the management of drug resistant ovarian cancer: dose dense chemotherapy and the reversal of clinical platinum resistance.

    Science.gov (United States)

    Pinato, David J; Graham, Janet; Gabra, Hani; Sharma, Rohini

    2013-04-01

    Despite the initially high response rate to standard front-line debulking surgery followed by platinum-based chemotherapy, the relapse rate in ovarian cancer is high and many patients will recur within 6 months of completing platinum based treatment. These patients may still require further chemotherapy despite being considered "platinum resistant". In this setting, response rates to conventionally scheduled second line platinum and non-platinum agents is low, ranging between 5% and 15%. There is an emerging body of evidence that in this scenario, chemotherapeutic activity can be enhanced using unconventionally scheduled "dose-dense" platinum and non-platinum based regimens with improved response rates of up to 65%. Randomised studies to evaluate the impact of this approach on survival in recurrent, platinum resistant disease are urgently required to confirm the promising phase II findings if there is to be a change in the standard of care of patients with platinum resistant disease. In this review we discuss the evolving strategies to overcome resistance in patients with platinum resistant ovarian cancer with a particular focus on alterations in dose schedule as a means of reversing platinum resistance. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Rearrangement of a (dithiolato)platinum(II) complex formed by reaction of cyclic disulfide 7,8-dithiabicyclo[4.2.1]nona-2,4-diene with a platinum(0) complex: Oxidation of the rearranged (dithiolato)platinum(II) complex

    OpenAIRE

    石井, 昭彦

    2007-01-01

    Reaction of the title bicyclic disulfide 16 with [(Ph3P)(2)Pt(eta(2)-C2H4)] (2) yielded the corresponding (dithiolato)platinum(II) complex 17 by oxidative addition. The initial product 17 isomerized at room temperature in a [1,5]-sulfur rearrangement to give another (dithiolato)platinum(II) complex 18 in high isolated yield. Oxidation reactions of 18 with dimethyldioxirane (DMD) provided (sulfenato-thiolato)platinum(II) 23, (sulfinato-thiolato)platinum(II) 24, (sulfenato-sulfinato)platinum(II...

  18. Harnessing chemoselective imine ligation for tethering bioactive molecules to platinum(IV) prodrugs.

    Science.gov (United States)

    Wong, Daniel Yuan Qiang; Lau, Jia Yi; Ang, Wee Han

    2012-05-28

    Platinum(II) anticancer drugs are among the most effective and often used chemotherapeutic drugs. In recent years, there has been increasing interest in exploiting inert platinum(IV) scaffolds as a prodrug strategy to mitigate the limitations of platinum(II) anticancer complexes. In this prodrug strategy, the axial ligands are released concomitantly upon intracellular reduction to the active platinum(II) congener, offering the possibility of conjugating bioactive co-drugs which may synergistically enhance cytotoxicity on cancer cells. Existing techniques of tethering bioactive molecules to the axial positions of platinum(IV) prodrugs suffer from limited scope, poor yields and low reliability. This report explores the applications of current chemoselective ligation chemistries to platinum(IV) anticancer complexes with the aim of addressing the aforementioned limitations. Here, we describe the synthesis of a platinum(IV) complex bearing an aromatic aldehyde functionality and explored the scope of imine ligation with various hydrazide and aminooxy functionalized substrates. As a proof of concept, we tethered a six sequence long peptide mimetic (AMVSEF) of the anti-inflammatory protein, ANXA1.

  19. Platinum Complexes with Edda (Ethylenediamine -N, N - Diacetate Ligands as Potential Anticancer Agents

    Directory of Open Access Journals (Sweden)

    Jurisevic Milena

    2016-12-01

    Full Text Available The design of platinum based drugs is not a new field of interest. Platinum complexes are widely used as anticancer agents and currently, approximately 30 platinum(II and platinum(IV entered into some of the phases of clinical trials. A special place in today’s research belongs to platinum complexes with diammine ligands. A large number of edda (ethylenediamine- N, N’-diacetate-type ligands and their corresponding metal complexes has been successfully synthesized. This article summarizes recent progress in research on edda-type-platinum complexes. Some of these agents achieves better effect compared to the gold standard (cisplatin. It has been shown that there is a possible relationship between the length of the ligand ester group carbon chain and its cytotoxic effect. In most cases the longer the ester chain is the greater is the antitumor activity. Of particular interest are the noticeable effects of some new platinum compound with edda-type ligand on cell lines that are known to have a high level of cisplatin-resistance. Exanimate complexes appear to have a different mode of mechanism of action compared with cisplatin which includes apoptotic and necrotic cell death. There are indications that further investigations of these compounds may be very useful in overcoming the problems associated global cancer statistic.

  20. Mono- and di-bromo platinum(IV) prodrugs via oxidative bromination: synthesis, characterization, and cytotoxicity.

    Science.gov (United States)

    Xu, Zoufeng; Wang, Zhigang; Yiu, Shek-Man; Zhu, Guangyu

    2015-12-14

    Platinum(IV)-based anticancer prodrugs have attracted much attention due to their relative inertness under physiological conditions, being activated inside cells, and their capacity for functionalization with a variety of small-molecule or macromolecule moieties. Novel asymmetric platinum(IV) compounds synthesized through expedient and unique methods are desired. Here we utilize N-bromosuccinimide (NBS) and carry out oxidative bromination on platinum(II) drugs, namely cisplatin, carboplatin, and oxaliplatin, to obtain asymmetric and mono-bromo platinum(IV) prodrugs. Different solvents are used to obtain various compounds, and the compounds are further functionalized. Di-bromo compounds are also obtained through NBS-directed oxidative bromination in ethanol. The crystal structures of representative compounds are discussed, and the reduction potentials of some compounds are examined. A cytotoxicity test shows that the mono- and di-bromo platinum(IV) compounds are active against human ovarian cancer cells. Our study enriches the family of asymmetric platinum(IV) prodrugs and provides with a convenient strategy to obtain brominated platinum(IV) complexes.