Structural features of AgCaCdMg2(PO4)3 and AgCd2Mg2(PO4)3, two new compounds with the alluaudite-type structure, and their catalytic activity in butan-2-ol conversion

International Nuclear Information System (INIS)

Kacimi, Mohammed; Ziyad, Mahfoud; Hatert, Frederic

2005-01-01

AgCaCdMg 2 (PO 4 ) 3 and AgCd 2 Mg 2 (PO 4 ) 3 , two new compounds with the alluaudite-type structure, were synthesized by a solid state reaction in air at 750 deg. C. The X-ray powder diffraction pattern of AgCaCdMg 2 (PO 4 ) 3 indicates the presence of small amounts of (Ca, Mg) 3 (PO 4 ) 2 with the whitlockite structure, as impurity, whereas AgCd 2 Mg 2 (PO 4 ) 3 is constituted by pure alluaudite. The Rietveld refinements of the X-ray powder diffraction patterns indicate an ordered cationic distribution for AgCd 2 Mg 2 (PO 4 ) 3 , with Ag on A(2)', Cd on A(1) and M(1), and Mg on M(2), whereas a disordered distribution of Cd and Ca between the A(1) and M(1) sites is observed for AgCaCdMg 2 (PO 4 ) 3 . The catalytic properties of these compounds has been measured in reaction of butan-2-ol dehydrogenation. In the absence of oxygen, both samples exhibit poor dehydrogenation activity. All samples displayed no dehydration activity. Introduction of oxygen into the feed changed totally the catalytic behavior of the catalysts. The production of methyl ethyl ketone increases with time on stream and the reaction temperature. AgCaCdMg 2 (PO 4 ) 3 is more efficient than AgCd 2 Mg 2 (PO 4 ) 3

Synthesis, characterizations and anti-bacterial activities of pure and Ag doped CdO nanoparticles by chemical precipitation method.

Science.gov (United States)

Sivakumar, S; Venkatesan, A; Soundhirarajan, P; Khatiwada, Chandra Prasad

2015-02-05

In the present study, synthesized pure and Ag (1%, 2%, and 3%) doped Cadmium Oxide (CdO) nanoparticles by chemical precipitation method. Then, the synthesized products were characterized by thermo gravimetric-differential thermal analysis (TG-DTA), X-ray diffraction (XRD) analysis, Fourier transform infrared (FT-IR) spectroscopy, Ultra violet-Vis diffused reflectance spectroscopy (UV-Vis-DRS), Scanning electron microscopy (SEM), Energy dispersive X-rays (EDX) spectroscopy, and anti-bacterial activities, respectively. The transition temperatures and phase transitions of Cd(OH)2 to CdO at 400°C was confirmed by TG-DTA analysis. The XRD patterns show the cubic shape and average particle sizes are 21, 40, 34, and 37nm, respectively for pure and Ag doped samples. FT-IR study confirmed the presence of CdO and Ag at 677 and 459cm(-1), respectively. UV-Vis-DRS study shows the variation on direct and indirect band gaps. The surface morphologies and elemental analysis have been confirmed from SEM and with EDX. In addition, the synthesized products have been characterized by antibacterial activities against Gram-positive and negative bacteria. Further, the present investigation suggests that CdO nanoparticles have the great potential applications on various industrial and medical fields of research. Copyright © 2014 Elsevier B.V. All rights reserved.

Optical studies of CdSe/HgSe and CdSe/Ag2Se core/shell nanoparticles embedded in gelatin

International Nuclear Information System (INIS)

Azhniuk, Yu M; Dzhagan, V M; Valakh, M Ya; Raevskaya, A E; Stroyuk, A L; Kuchmiy, S Ya; Zahn, D R T

2008-01-01

CdSe/HgSe and CdSe/Ag 2 Se core-shell nanoparticles are obtained by colloidal synthesis from aqueous solutions in the presence of gelatin. Optical absorption, luminescence, and Raman spectra of the nanoparticles obtained are measured. The variation of the optical spectra of CdSe/HgSe and CdSe/Ag 2 Se core-shell nanoparticles with the shell thickness is discussed. Sharp non-monotonous variation of the photoluminescence spectra at low shell coverage is observed.

Ag and CdS nanoparticles co-sensitized TiO2 nanotubes for enhancing visible photoelectrochemical performance

International Nuclear Information System (INIS)

Wang Qingyao; Yang Xiuchun; Liu Dan; Chi Lina; Hou Junwei

2012-01-01

Highlights: ► Ag and CdS nanoparticles co-sensitized TiO 2 nanotubes were fabricated by the SILAR method. ► The co-sensitization expands the photoresponse range of TiO 2 NTs to 668.7 nm. ► Visible light photocurrents and photocatalytic activities of CdS–Ag/TiO 2 NTs were studied. ► The electron transfer mechanism of CdS–Ag/TiO 2 NTs was proposed. - Abstract: The Ag and CdS nanoparticles co-sensitization of TiO 2 nanotubes (CdS–Ag/TiO 2 NTs) were prepared by successive ionic layer adsorption and reaction (SILAR) technique. The phase composition, morphology and optical property were characterized by the X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–vis diffusion reflection spectroscopy (DRS). The co-modification of Ag and CdS nanoparticles expanded the photoresponse range of TiO 2 NTs from ultraviolet region to 668.7 nm, and the CdS–Ag/TiO 2 NTs prepared by SILAR deposition of 5 cycles exhibited higher visible photocurrent and stability against photocorrosion. The detailed electrons transfer mechanism of CdS–Ag/TiO 2 NTs was proposed, and photocatalytic activity toward degradation of methyl orange (MO) under visible-light irradiation was also investigated.

Cladding technique for development of Ag-In-Cd decoupler

International Nuclear Information System (INIS)

Teshigawara, M.; Harada, M.; Saito, S.; Kikuchi, K.; Kogawa, H.; Ikeda, Y.; Kawai, M.; Kurishita, H.; Konashi, K.

2005-01-01

To develop a Ag (silver)-In (indium)-Cd (cadmium) alloy decoupler, a method is needed to bond the decoupler between two plates of the Al alloy (A6061-T6). We found that a better HIP condition was temperature, pressure and holding time at 803 K, 100 MPa and 1 h, respectively, for small test pieces (φ 22 mm in diam. x 5 mm in height). Especially, a sandwich case (a Ag-In plate with thickness of 0.5 mm between two Ag-Cd plates with thickness of 1.25 mm) gave easier (or better) bonding results. Though a hardened layer is found in the bonding layer, the rupture strength of the bonding layer is more than 30 MPa, which is higher than the design stress in our application

Enhanced selective photocatalytic CO{sub 2} reduction into CO over Ag/CdS nanocomposites under visible light

Energy Technology Data Exchange (ETDEWEB)

Zhu, Zezhou; Qin, Jiani; Jiang, Min; Ding, Zhengxin; Hou, Yidong, E-mail: ydhou@fzu.edu.cn

2017-01-01

Highlights: • Ag/CdS nanocomposites were prepared by a facile photodeposition method. • Ag/CdS was more effective as a photocatalyst for CO{sub 2} reduction than CdS. • Ag as cocatalyst served as electron trap as well as active site for CO{sub 2} reduction reaction. - Abstract: Photocatalytic reduction of carbon dioxide can convert chemically inert carbon dioxide into useful chemical fuel in a mild manner. Herein, Ag-CdS nanocomposites were prepared by photodeposition method and examined for photocatalytic CO{sub 2} reduction under visible light. Meanwhile, the nanocomposites were characterized by XRD, SEM, TEM, XPS, DRS and PL in detail. The results show that, the deposition of Ag improves the photocatalytic performance of CdS, especially in the selectivity of CO{sub 2}-to-CO. The highest photocatalytic activity is achieved over 1.0 wt.% Ag/CdS, with an increase by 3 times in comparison to CdS. In this reaction system, Ag can serve as electron trap as well as active site for CO{sub 2} reduction, which is probably responsible for the enhanced activity and selectivity of CO{sub 2} to CO over Ag/CdS. The possible mechanism of CO{sub 2} photoreduction over Ag/CdS was proposed in view of the abovementioned analysis.

Target swapping in PLD: An efficient approach for CdS/SiO2 and CdS:Ag(1%)/SiO2 nanocomposite thin films with enhanced luminescent properties

International Nuclear Information System (INIS)

Saxena, Nupur; Kumar, Pragati; Gupta, Vinay

2017-01-01

A novel synthesis method for luminescent and by-products (like CdO) free CdS/SiO 2 and CdS:Ag(1%)/SiO 2 (i.e. 1%Ag doped CdS/SiO 2 ) nanocomposite thin films at room temperature by pulsed laser deposition is reported. Targets of CdS, CdS:Ag(1%) and SiO 2 are used to deposit CdS/SiO 2 and CdS:Ag(1%)/SiO 2 nanocomposite thin films by swapping them at a frequency ratio of 2:8 laser pulses/sec. X-ray photoelectron spectroscopy analysis ensures the ratio of CdS to SiO 2 in nanocomposite as 21:79 which is nearly same as the ratio of incident pulses/sec (i.e. 2:8) on the two targets. Transmission electron micrographs visualize the formation of CdS/ CdS:Ag(1%) nanocrystals in nanocomposite systems after annealing at 500 °C. Highly intense and broad red emission is achieved from CdS/SiO 2 and CdS:Ag(1%)/SiO 2 nanocomposites. The efficiencies of emission from pristine CdS:SiO 2 and CdS:Ag(1%)/SiO 2 nanocomposites are found to be enhanced by approximately two times as compared to sole nanocrystalline CdS and CdS:Ag(1%) thin films respectively and further enhanced upto 7 times on annealing the nanocomposite systems at 500 °C. - Graphical abstract: A modified synthesis method for luminescent and by-products (like CdO) free undoped &1% Ag doped CdS/SiO 2 (deposit CdS/SiO 2 and CdS:Ag(1%)/SiO 2 ) nanocomposite thin films at room temperature by pulsed laser deposition is reported. Targets of CdS or CdS:Ag(1%) and SiO 2 are used to deposit CdS/SiO 2 and CdS:Ag(1%)/SiO 2 nanocomposite thin films by swapping them at a frequency of 2:8 pulses/sec. X-ray photoelectron spectroscopy analysis ensures the ratio of CdS to SiO 2 in nanocomposite as 21:79 which is nearly same as the ratio of incident pulses/sec (2:8) on the two targets. Transmission electron micrographs visualize the formation of CdS nanocrystals in nanocomposite systems after annealing at 500 °C. Intense and broad red emission is achieved from deposit CdS/SiO 2 and CdS:Ag(1%)/SiO 2 nanocomposites. The efficiency of

Third-order nonlinear optical response of Ag-CdSe/PVA hybrid nanocomposite

Energy Technology Data Exchange (ETDEWEB)

Tripathi, S.K.; Kaur, Ramneek; Kaur, Jaspreet; Sharma, Mamta [Panjab University, Department of Physics, Center of Advanced Study in Physics, Chandigarh (India)

2015-09-15

Hybrid nanocomposites of II-VI semiconductor nanoparticles are gaining great interest in nonlinear optoelectronic devices. Present work includes the characterization of CdSe polymer nanocomposite prepared by chemical in situ technique. From X-ray diffraction, the hexagonal wurtzite structure of nanoparticles has been confirmed with spherical morphology from transmission electron microscopy. Ag-CdSe hybrid polymer nanocomposite has been prepared chemically at different Ag concentrations. The presence of Ag in hybrid nanocomposite has been confirmed with energy-dispersive X-ray spectroscopy. The effect of varying Ag concentration on the linear and nonlinear optical properties of the nanocomposites has been studied. In linear optical parameters, the linear absorption coefficient, refractive index, extinction coefficient and optical conductivity have been calculated. The third-order nonlinear optical properties have been observed with open- and closed-aperture Z-scan technique. The large nonlinear refractive index ∝10{sup -5} cm{sup 2}/W with self-focusing behaviour is due to the combined effect of quantum confinement and thermo-optical effects. The enhanced nonlinearity with increasing Ag content is due to the surface plasmon resonance, which enhances the local electric field near the nanoparticle surface. Thus, Ag-CdSe hybrid polymer nanocomposite has favourable nonlinear optical properties for various optoelectronic applications. (orig.)

Third-order nonlinear optical response of Ag-CdSe/PVA hybrid nanocomposite

International Nuclear Information System (INIS)

Tripathi, S.K.; Kaur, Ramneek; Kaur, Jaspreet; Sharma, Mamta

2015-01-01

Hybrid nanocomposites of II-VI semiconductor nanoparticles are gaining great interest in nonlinear optoelectronic devices. Present work includes the characterization of CdSe polymer nanocomposite prepared by chemical in situ technique. From X-ray diffraction, the hexagonal wurtzite structure of nanoparticles has been confirmed with spherical morphology from transmission electron microscopy. Ag-CdSe hybrid polymer nanocomposite has been prepared chemically at different Ag concentrations. The presence of Ag in hybrid nanocomposite has been confirmed with energy-dispersive X-ray spectroscopy. The effect of varying Ag concentration on the linear and nonlinear optical properties of the nanocomposites has been studied. In linear optical parameters, the linear absorption coefficient, refractive index, extinction coefficient and optical conductivity have been calculated. The third-order nonlinear optical properties have been observed with open- and closed-aperture Z-scan technique. The large nonlinear refractive index ∝10 -5 cm 2 /W with self-focusing behaviour is due to the combined effect of quantum confinement and thermo-optical effects. The enhanced nonlinearity with increasing Ag content is due to the surface plasmon resonance, which enhances the local electric field near the nanoparticle surface. Thus, Ag-CdSe hybrid polymer nanocomposite has favourable nonlinear optical properties for various optoelectronic applications. (orig.)

Quantum dot sensitized solar cell based on TiO2/CdS/Ag2S heterostructure

Science.gov (United States)

Pawar, Sachin A.; Patil, Dipali S.; Kim, Jin Hyeok; Patil, Pramod S.; Shin, Jae Cheol

2017-04-01

Quantum dot sensitized solar cell (QDSSC) is fabricated based on a stepwise band structure of TiO2/CdS/Ag2S to improve the photoconversion efficiency of TiO2/CdS system by incorporating a low band gap Ag2S QDs. Vertically aligned TiO2 nanorods assembly is prepared by a simple hydrothermal technique. The formation of CdS and Ag2S QDs over TiO2 nanorods assembly as a photoanode is carried out by successive ionic layer adsorption and reaction (SILAR) technique. The synthesized electrode materials are characterized by XRD, XPS, field emission scanning electron microscopy (FE-SEM), Optical, solar cell and electrochemical performances. The results designate that the QDs of CdS and Ag2S have efficiently covered exterior surfaces of TiO2 nanorods assembly. A cautious evaluation between TiO2/CdS and TiO2/CdS/Ag2S sensitized cells tells that CdS and Ag2S synergetically helps to enhance the light harvesting ability. Under AM 1.5G illumination, the photoanodes show an improved power conversion efficiency of 1.87%, in an aqueous polysulfide electrolyte with short-circuit photocurrent density of 7.03 mA cm-2 which is four fold higher than that of a TiO2/CdS system.

Target swapping in PLD: An efficient approach for CdS/SiO{sub 2} and CdS:Ag(1%)/SiO{sub 2} nanocomposite thin films with enhanced luminescent properties

Energy Technology Data Exchange (ETDEWEB)

Saxena, Nupur, E-mail: n1saxena@gmail.com [Department of Physics & Astrophysics, University of Delhi, Delhi 110007 (India); Kumar, Pragati, E-mail: pkumar.phy@gmail.com [Department of Physics & Astrophysics, University of Delhi, Delhi 110007 (India); Department of Nano Sciences and Materials, Central University of Jammu, Rahya-Suchani (Bagla), Samba, 181143 Jammu, J& K (India); Gupta, Vinay [Department of Physics & Astrophysics, University of Delhi, Delhi 110007 (India)

2017-06-15

A novel synthesis method for luminescent and by-products (like CdO) free CdS/SiO{sub 2} and CdS:Ag(1%)/SiO{sub 2} (i.e. 1%Ag doped CdS/SiO{sub 2}) nanocomposite thin films at room temperature by pulsed laser deposition is reported. Targets of CdS, CdS:Ag(1%) and SiO{sub 2} are used to deposit CdS/SiO{sub 2} and CdS:Ag(1%)/SiO{sub 2} nanocomposite thin films by swapping them at a frequency ratio of 2:8 laser pulses/sec. X-ray photoelectron spectroscopy analysis ensures the ratio of CdS to SiO{sub 2} in nanocomposite as 21:79 which is nearly same as the ratio of incident pulses/sec (i.e. 2:8) on the two targets. Transmission electron micrographs visualize the formation of CdS/ CdS:Ag(1%) nanocrystals in nanocomposite systems after annealing at 500 °C. Highly intense and broad red emission is achieved from CdS/SiO{sub 2} and CdS:Ag(1%)/SiO{sub 2} nanocomposites. The efficiencies of emission from pristine CdS:SiO{sub 2} and CdS:Ag(1%)/SiO{sub 2} nanocomposites are found to be enhanced by approximately two times as compared to sole nanocrystalline CdS and CdS:Ag(1%) thin films respectively and further enhanced upto 7 times on annealing the nanocomposite systems at 500 °C. - Graphical abstract: A modified synthesis method for luminescent and by-products (like CdO) free undoped &1% Ag doped CdS/SiO{sub 2} (deposit CdS/SiO{sub 2} and CdS:Ag(1%)/SiO{sub 2}) nanocomposite thin films at room temperature by pulsed laser deposition is reported. Targets of CdS or CdS:Ag(1%) and SiO{sub 2} are used to deposit CdS/SiO{sub 2} and CdS:Ag(1%)/SiO{sub 2} nanocomposite thin films by swapping them at a frequency of 2:8 pulses/sec. X-ray photoelectron spectroscopy analysis ensures the ratio of CdS to SiO{sub 2} in nanocomposite as 21:79 which is nearly same as the ratio of incident pulses/sec (2:8) on the two targets. Transmission electron micrographs visualize the formation of CdS nanocrystals in nanocomposite systems after annealing at 500 °C. Intense and broad red emission is

Ag2S/CdS/TiO2 Nanotube Array Films with High Photocurrent Density by Spotting Sample Method.

Science.gov (United States)

Sun, Hong; Zhao, Peini; Zhang, Fanjun; Liu, Yuliang; Hao, Jingcheng

2015-12-01

Ag2S/CdS/TiO2 hybrid nanotube array films (Ag2S/CdS/TNTs) were prepared by selectively depositing a narrow-gap semiconductor-Ag2S (0.9 eV) quantum dots (QDs)-in the local domain of the CdS/TiO2 nanotube array films by spotting sample method (SSM). The improvement of sunlight absorption ability and photocurrent density of titanium dioxide (TiO2) nanotube array films (TNTs) which were obtained by anodic oxidation method was realized because of modifying semiconductor QDs. The CdS/TNTs, Ag2S/TNTs, and Ag2S/CdS/TNTs fabricated by uniformly depositing the QDs into the TNTs via the successive ionic layer adsorption and reaction (SILAR) method were synthesized, respectively. The X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectrum (XPS) results demonstrated that the Ag2S/CdS/TNTs prepared by SSM and other films were successfully prepared. In comparison with the four films of TNTs, CdS/TNTs, Ag2S/TNTs, and Ag2S/CdS/TNTs by SILAR, the Ag2S/CdS/TNTs prepared by SSM showed much better absorption capability and the highest photocurrent density in UV-vis range (320~800 nm). The cycles of local deposition have great influence on their photoelectric properties. The photocurrent density of Ag2S/CdS/TNTs by SSM with optimum deposition cycles of 6 was about 37 times that of TNTs without modification, demonstrating their great prospective applications in solar energy utilization fields.

Effect of Silicon on Activity Coefficients of P, Bl, CD, SN, and AG in Liquid Fe-Si, and Implications for Differentiation and Core Formation

Science.gov (United States)

Righter, K.; Pando, K.; Ross, D. K.

2017-01-01

Cores of differentiated bodies (Earth, Mars, Mercury, Moon, Vesta) contain light elements such as S, C, Si, and O. We have previously measured small effects of Si on metal-silicate partitioning of Ni and Co [1,2], and larger effects for Mo, Ge, Sb, As [2]. The effect of Si on many siderophile elements could be an important, and as yet unquantified, influence on the core-mantle partitioning of SE. Here we report new experiments designed to quantify the effect of Si on the partitioning of Bi, Cd, Sn, Ag, and P between metal and silicate melt. The results will be applied to Earth, Mars, Mercury, Moon, and Vesta, for which we have excellent constraints on the mantle Bi, Cd, Sn, Ag, and P concentrations from mantle and/or basalt samples.

The design of novel visible light driven Ag/CdO as smart nanocomposite for photodegradation of different dye contaminants

Science.gov (United States)

Saravanakumar, K.; Muthuraj, V.; Jeyaraj, M.

2018-01-01

In this paper, we report a novel visible light driven Ag/CdO photocatalyst, fabricated for the first time via one pot hydrothermal method and further applied for the photodegradation of two important exemplar water contaminants, Malachite green and Acid Orange 7. The microstructure, composition and optical properties of Ag/CdO nanocomposites were thoroughly investigated by various techniques. Scanning electron microscopy clearly shows that Ag NPs were strongly embedded between the CdO nanoparticles. Among the series of synthesized Ag/CdO nanocomposites, (5%) Ag/CdO nanocomposite possesses enhanced photocatalytic activity. This result was attributed to the synergistic effect between Ag and CdO, and mainly Ag NPs can act as an electron trap site, which could reduce the recombination of the electron-hole and induce the visible light absorption. The active species trapping experiments implicate radOH and O2rad - radicals as the respective primary and secondary reactive species responsible for oxidative photodegradation of organic pollutants. On the basis of the results, a possible photocatalytic mechanism has also been proposed.

Distributions of dissolved trace metals (Cd, Cu, Mn, Pb, Ag in the southeastern Atlantic and the Southern Ocean

Directory of Open Access Journals (Sweden)

M. Boye

2012-08-01

Full Text Available Comprehensive synoptic datasets (surface water down to 4000 m of dissolved cadmium (Cd, copper (Cu, manganese (Mn, lead (Pb and silver (Ag are presented along a section between 34° S and 57° S in the southeastern Atlantic Ocean and the Southern Ocean to the south off South Africa. The vertical distributions of Cu and Ag display nutrient-like profiles similar to silicic acid, and of Cd similar to phosphate. The distribution of Mn shows a subsurface maximum in the oxygen minimum zone, whereas Pb concentrations are rather invariable with depth. Dry deposition of aerosols is thought to be an important source of Pb to surface waters close to South Africa, and dry deposition and snowfall may have been significant sources of Cu and Mn at the higher latitudes. Furthermore, the advection of water masses enriched in trace metals following contact with continental margins appeared to be an important source of trace elements to the surface, intermediate and deep waters in the southeastern Atlantic Ocean and the Antarctic Circumpolar Current. Hydrothermal inputs may have formed a source of trace metals to the deep waters over the Bouvet Triple Junction ridge crest, as suggested by relatively enhanced dissolved Mn concentrations. The biological utilization of Cu and Ag was proportional to that of silicic acid across the section, suggesting that diatoms formed an important control over the removal of Cu and Ag from surface waters. However, uptake by dino- and nano-flagellates may have influenced the distribution of Cu and Ag in the surface waters of the subtropical Atlantic domain. Cadmium correlated strongly with phosphate (P, yielding lower Cd / P ratios in the subtropical surface waters where phosphate concentrations were below 0.95 μM. The greater depletion of Cd relative to P observed in the Weddell Gyre compared to the Antarctic Circumpolar Current could be due to increase Cd uptake induced by iron-limiting conditions in these high

New chalcogenide glasses in the CdTe-AgI-As{sub 2}Te{sub 3} system

Energy Technology Data Exchange (ETDEWEB)

Kassem, M. [Univ. Picardie Jules Verne, F-80000 Amiens (France); Le Coq, D., E-mail: david.lecoq@univ-littoral.fr [Univ. Lille Nord de France, F-59000 Lille (France); ULCO, LPCA, EA 4493, F-59140 Dunkerque (France); Boidin, R.; Bychkov, E. [Univ. Lille Nord de France, F-59000 Lille (France); ULCO, LPCA, EA 4493, F-59140 Dunkerque (France)

2012-02-15

Highlights: Black-Right-Pointing-Pointer Determination of the glass-forming region in the pseudo-ternary CdTe-AgI-As{sub 2}Te{sub 3} system. Black-Right-Pointing-Pointer Characterization of macroscopic properties of the new CdTe-AgI-As{sub 2}Te{sub 3} glasses. Black-Right-Pointing-Pointer Characterization of the total conductivity of CdTe-AgI-As{sub 2}Te{sub 3} glasses. Black-Right-Pointing-Pointer Comparison between the selenide and telluride equivalent systems. -- Abstract: Chalcogenide glasses in the pseudo-ternary CdTe-AgI-As{sub 2}Te{sub 3} system were synthesized and the glass-forming range was determined. The maximum content of CdTe in this glass system was found to be equal to 15 mol.%. The macroscopic characterizations of samples have consisted in Differential Scanning Calorimetry, density, and X-ray diffraction measurements. The cadmium telluride addition does not generate any significant change in the glass transition temperature but the resistance of binary AgI-As{sub 2}Te{sub 3} glasses towards crystallisation is estimated to be decreasing on the base of {Delta}T = T{sub x} - T{sub g} parameter. The total electrical conductivity {sigma} was measured by complex impedance spectroscopy. First, the CdTe additions in the (AgI){sub 0.5}(As{sub 2}Te{sub 3}){sub 0.5} host glass, (CdTe){sub x}(AgI){sub 0.5-x/2}(As{sub 2}Te{sub 3}){sub 0.5-x/2} lead to a conductivity decrease at x {<=} 0.05. Then, the behaviour is reversed at 0.05 {<=} x {<=} 0.15. The obtained results are discussed by comparison with the equivalent selenide system.

Investigation of effect of Ag(1), Cd(2) and Zn(2) on chemical nickel plating

International Nuclear Information System (INIS)

Lunyatskas, A.M.; Tarozajte, R.K.; Gyanutene, I.K.; Lyaukonis, Yu.Yu.

1978-01-01

Investigated is the effect of Ag(1), Cd(2) and Zn(2) on chemical nickel plating using hypophosphite aimed to get corresponding alloys from alkali solutions. The H 2 formed volume and potential of coating have been measured while nickel plating. It is possible to have plating of Ni-P-Ag, Ni-P-Zn, Ni-P-Cd, Ni-P-Zn-Cd content coatings in alkali solutions using hypophosphite Ni-P-Zh and Ni-P-Zn-Cd coatings have corrosion resistance and unporousness. Cd and Zn inclusion in Ni-P coating is supposed to have both chemical and electrochemical origin

Synthesis and properties of new CdSe-AgI-As2Se3 chalcogenide glasses

International Nuclear Information System (INIS)

Kassem, M.; Le Coq, D.; Fourmentin, M.; Hindle, F.; Bokova, M.; Cuisset, A.; Masselin, P.; Bychkov, E.

2011-01-01

Research highlights: → Determination of the glass-forming region in the pseudo-ternary CdSe-AgI-As 2 Se 3 system. → Characterization of macroscopic properties of the new CdSe-AgI-As 2 Se 3 glasses. → Far infrared transmission of chalcogenide glasses. → Characterization of the total conductivity of CdSe-AgI-As 2 Se 3 glasses. -- Abstract: The glass-forming region in the pseudo-ternary CdSe-AgI-As 2 Se 3 system was determined. Measurements including differential scanning calorimetry (DSC), density, and X-ray diffraction were performed. The effect resulting from the addition of CdSe or AgI has been highlighted by examining three series of different base glasses. The characteristic temperatures of the glass samples, including glass transition (T g ), crystallisation (T x ), and melting (T m ) temperatures are reported and used to calculate their ΔT = T x - T g and their Hruby, H r = (T x - T g )/(T m - T x ), criteria. Evolution of the total electrical conductivity σ and the room temperature conductivity σ 298 was also studied. The terahertz transparency domain in the 50-600 cm -1 region was pointed for different chalcogenide glasses (ChGs) and the potential of the THz spectroscopy was suggested to obtain structural information on ChGs.

Ag2S/CdS/TiO2 Nanotube Array Films with High Photocurrent Density by Spotting Sample Method

OpenAIRE

Sun, Hong; Zhao, Peini; Zhang, Fanjun; Liu, Yuliang; Hao, Jingcheng

2015-01-01

Ag2S/CdS/TiO2 hybrid nanotube array films (Ag2S/CdS/TNTs) were prepared by selectively depositing a narrow-gap semiconductor—Ag2S (0.9 eV) quantum dots (QDs)—in the local domain of the CdS/TiO2 nanotube array films by spotting sample method (SSM). The improvement of sunlight absorption ability and photocurrent density of titanium dioxide (TiO2) nanotube array films (TNTs) which were obtained by anodic oxidation method was realized because of modifying semiconductor QDs. The CdS/TNTs, Ag2S/TNT...

CD209-336A/G promotor polymorphism and its clinical associations in sickle cell disease Egyptian Pediatric patients.

Science.gov (United States)

Afifi, Rasha Abdel-Raouf; Kamal, Dina; Sayed, Riham El; Ekladious, Sherif M M; Shaheen, Gehan H; Yousry, Sherif M; Hussein, Rania Elsayed

2018-06-01

To detect the frequency of CD209 A>G polymorphism in sickle cell disease (SCD) Egyptian patients and to evaluate the use of CD209 A>G polymorphism as a genetic predictor of SCD clinical heterogeneity. A total of 100 Egyptian children with SCD and 100 Egyptian controls were tested for CD209 A>G polymorphism and were followed up prospectively between June 2012 and December 2014. Comparison of CD209 A>G polymorphism among cases and controls did not show statistically significant difference (p = .742). In addition, comparison of the allelic frequency did not show statistically significant difference (p = .738). Infections occurred more frequently among the heterozygous genotype (AG; 60.5%) and homozygous genotype (GG; 75%) patients than among the wild (AA) genotype (24.1%; p G polymorphism. Infections occurred more frequently among the heterozygous genotype (AG) and homozygous genotype (GG) patients. Copyright © 2017. Published by Elsevier Ltd.

Ionic-to-Electronic Conductivity Crossover in CdTe-AgI-As2Te3 Glasses: An 110mAg Tracer Diffusion Study.

Science.gov (United States)

Kassem, M; Alekseev, I; Bokova, M; Le Coq, D; Bychkov, E

2018-04-12

Conductivity isotherms of (CdTe) x (AgI) 0.5- x/2 (As 2 Te 3 ) 0.5- x/2 glasses (0.0 ≤ x ≤ 0.15) reveal a nonmonotonic behavior with increasing CdTe content reminiscent of mixed cation effect in oxide and chalcogenide glasses. Nevertheless, the apparent similarity appears to be partly incorrect. Using 110m Ag tracer diffusion measurements, we show that semiconducting CdTe additions produce a dual effect: (i) decreasing the Ag + ion transport by a factor of ≈200 with a simultaneous increase of the diffusion activation energy and (ii) increasing the electronic conductivity by 1.5 orders of magnitude. Consequently, the conductivity minimum at x = 0.05 reflects an ionic-to-electronic transport crossover; the silver-ion transport number decreases by 3 orders of magnitude with increasing x.

The clinical significance of serum SCC-Ag combined with CD105 in patients with cervical cancer during the early stage diagnosis

Directory of Open Access Journals (Sweden)

Ru-Chan Ma

2016-09-01

Full Text Available Objective: To invest the clinical significance of serum SCC-Ag combined with CD105 in early diagnosis of cervical cancer to provide new ideas for early diagnosis and clinical treatment of cervical cancer. Methods: A total of 74 cases cervical cancer patients were selected as cervical cancer group, and 52 cases uterine fibroids patients were selected as normal cervical group, serum samples were collected in the early morning fasting condition, SCC-Ag and CD105 were checked by ELISA method, SCC-Ag and CD105 of two groups were analyzed by t-test, and to compare SCC-Ag and CD105 in different TMN staging, lymph gland metastasis and non-lymph gland metastasis in patients with cervical cancer, the correlation analysis was used by Pearson correlation analysis method. Results: These results came from ELISA method, comparing with normal cervical group, the SCC-Ag and CD105 of cervical cancer group increased, the difference was statistically significant. Comparing with Ⅰ period of TMN staging, SCC-Ag and CD105 of Ⅱ period increased, Ⅲ, Ⅳ period increased, the difference was statistically significant. Comparing with Ⅱ period, SCC-Ag and CD105 of Ⅲ, Ⅳ period increased, the difference was statistically significant. Comparing with non-lymph gland metastasis, SCC-Ag and CD105 of lymph gland metastasis increased in cervical cancer with surgical treatment, the difference was statistically significant. According to Pearson correlation analysis, SCC-Ag and CD105 were positively correlated. Conclusion: SCC-Ag and CD105 in patients with cervical cancer increase highly, it has important clinical value that of serum SCCAg combined with CD105 in the early diagnosis of cervical cancer, especially it has clinical guiding significance to staging and lymph gland metastasis of cervical cancer, and it is worthy of clinical reference.

Synthesis and luminescence properties of (Zn,Cd)S:Ag nanocrystals by hydrothermal method

International Nuclear Information System (INIS)

Luo Xixian; Cao Wanghe; Zhou Lixin

2007-01-01

ZnS:Ag and (Zn,Cd)S:Ag nanoparticles with particle sizes of about 50 and 150 nm have been prepared by hydrothermal method. The effects of hydrothermal process on the physical and luminescence characteristics are investigated. The photoluminescence intensities of hydrothermal treatment ZnS:Ag samples are 10 times higher than that of non-treated samples after annealing at 800 deg. C

AgCl-doped CdSe quantum dots with near-IR photoluminescence.

Science.gov (United States)

Kotin, Pavel Aleksandrovich; Bubenov, Sergey Sergeevich; Mordvinova, Natalia Evgenievna; Dorofeev, Sergey Gennadievich

2017-01-01

We report the synthesis of colloidal CdSe quantum dots doped with a novel Ag precursor: AgCl. The addition of AgCl causes dramatic changes in the morphology of synthesized nanocrystals from spherical nanoparticles to tetrapods and finally to large ellipsoidal nanoparticles. Ellipsoidal nanoparticles possess an intensive near-IR photoluminescence ranging up to 0.9 eV (ca. 1400 nm). In this article, we explain the reasons for the formation of the ellipsoidal nanoparticles as well as the peculiarities of the process. The structure, Ag content, and optical properties of quantum dots are also investigated. The optimal conditions for maximizing both the reaction yield and IR photoluminescence quantum yield are found.

Effect of Ag doping on opto-electrical properties of CdS thin films for solar cell applications

International Nuclear Information System (INIS)

Nazir, Adnan; Toma, Andrea; Shah, Nazar Abbas; Panaro, Simone; Butt, Sajid; Sagar, Rizwan ur Rehman; Raja, Waseem; Rasool, Kamran; Maqsood, Asghari

2014-01-01

Highlights: • Polycrystalline CdS thin films are fabricated by means of Close Spaced Sublimation technique. • Ag is doped by simple ion-exchange technique in order to reduce resistivity of CdS thin films. • Remarkable reduction in resistivity without introducing many transparency losses. - Abstract: Cadmium sulfide (CdS) polycrystalline thin films of different thicknesses (ranging from 370 nm to 750 nm) were fabricated on corning glass substrates using Close Spaced Sublimation (CSS) technique. Optical and electrical investigation revealed that CdS thin films show an appreciable transparency (50–70% transmission) in visible range and a highly resistive behavior (10 6 Ω cm). Samples were doped by silver (Ag) at different concentrations, using ion exchange technique, in order to reduce the resistivity of CdS thin films and to improve their efficiency as a window layer for solar cell application. The doping of Ag in pure CdS thin films resulted into an increase of surface roughness and a decrease both in electrical resistivity and in transparency. By optimizing annealing parameters, we were able to properly control the optical properties of the present system. In fact, the Ag doping of pure CdS films has led to a decrease of the sample resistivity by three orders of magnitude (10 3 Ω cm) against a 20% cut in optical transmission

Synthesis and properties of new CdSe-AgI-As{sub 2}Se{sub 3} chalcogenide glasses

Energy Technology Data Exchange (ETDEWEB)

Kassem, M. [Univ Lille Nord de France, F-59000 Lille (France); ULCO, LPCA, EAC CNRS 4493 F-59140 Dunkerque (France); Le Coq, D., E-mail: david.lecoq@univ-littoral.fr [Univ Lille Nord de France, F-59000 Lille (France); ULCO, LPCA, EAC CNRS 4493 F-59140 Dunkerque (France); Fourmentin, M.; Hindle, F.; Bokova, M.; Cuisset, A.; Masselin, P.; Bychkov, E. [Univ Lille Nord de France, F-59000 Lille (France); ULCO, LPCA, EAC CNRS 4493 F-59140 Dunkerque (France)

2011-02-15

Research highlights: {yields} Determination of the glass-forming region in the pseudo-ternary CdSe-AgI-As{sub 2}Se{sub 3} system. {yields} Characterization of macroscopic properties of the new CdSe-AgI-As{sub 2}Se{sub 3} glasses. {yields} Far infrared transmission of chalcogenide glasses. {yields} Characterization of the total conductivity of CdSe-AgI-As{sub 2}Se{sub 3} glasses. -- Abstract: The glass-forming region in the pseudo-ternary CdSe-AgI-As{sub 2}Se{sub 3} system was determined. Measurements including differential scanning calorimetry (DSC), density, and X-ray diffraction were performed. The effect resulting from the addition of CdSe or AgI has been highlighted by examining three series of different base glasses. The characteristic temperatures of the glass samples, including glass transition (T{sub g}), crystallisation (T{sub x}), and melting (T{sub m}) temperatures are reported and used to calculate their {Delta}T = T{sub x} - T{sub g} and their Hruby, H{sub r} = (T{sub x} - T{sub g})/(T{sub m} - T{sub x}), criteria. Evolution of the total electrical conductivity {sigma} and the room temperature conductivity {sigma}{sub 298} was also studied. The terahertz transparency domain in the 50-600 cm{sup -1} region was pointed for different chalcogenide glasses (ChGs) and the potential of the THz spectroscopy was suggested to obtain structural information on ChGs.

Stepwise synthesis of cubic Au-AgCdS core-shell nanostructures with tunable plasmon resonances and fluorescence.

Science.gov (United States)

Liu, Xiao-Li; Liang, Shan; Nan, Fan; Pan, Yue-Yue; Shi, Jun-Jun; Zhou, Li; Jia, Shuang-Feng; Wang, Jian-Bo; Yu, Xue-Feng; Wang, Qu-Quan

2013-10-21

Cubic Au-AgCdS core-shell nanostructures were synthesized through cation exchange method assisted by tributylphosphine (TBP) as a phase-transfer agent. Among intermediate products, Au-Ag core-shell nanocubes exhibited many high-order plasmon resonance modes related to the special cubic shape, and these plasmon bands red-shifted along with the increasing of particle size. The plasmon band of Au core first red-shifted and broadened at the step of Au-Ag₂S and then blue-shifted and narrowed at the step of Au-AgCdS. Since TBP was very crucial for the efficient conversion from Ag₂S to CdS, we found that both absorption and fluorescence of the final products could be controlled by TBP.

Ion implantation of Cd and Ag into AlN and GaN

CERN Document Server

Miranda, Sérgio M C; Correia, João Guilherme; Vianden, Reiner; Johnston, Karl; Alves, Eduardo; Lorenz, Katharina

2012-01-01

GaN and AlN thin films were implanted with cadmium (Cd) or silver (Ag), to fluences ranging from 1×1013 to 1.7 × 1015 at/cm$^{2}$. The implanted samples were annealed at 950 ºC under flowing nitrogen. While implantation damage could be fully removed for the lowest fluences, for higher fluences the crystal quality was only partially recovered. For the high fluence samples the lattice site location of the ions was studied by Rutherford Backscattering/ channelling (RBS/C). Cd ions are found to be incorporated in substitutional cation sites (Al or Ga) while Ag is slightly displaced from this position. To further investigate the incorporation sites, Perturbed Angular Correlation (PAC) measurements were performed and the electric field gradients at the site of the probe nuclei were determined.

Rudimentary simple, single step fabrication of nano-flakes like AgCd alloy electro-catalyst for oxygen reduction reaction in alkaline fuel cell

International Nuclear Information System (INIS)

Bhandary, Nimai; Basu, Suddhasatwa; Ingole, Pravin P.

2016-01-01

In this work, for the first time, we report rudimentary simple, single step fabrication of an electro-catalyst based on AgCd alloy nanoparticles with flakes like geometry which shows highly efficient activity towards oxygen reduction reaction (ORR). A simple potentiostatic deposition method has been employed for co-depositing AgCd alloy nanostructures with flakes like shapes along with dendrites on the surface of carbon fibre paper. The chemico-physical properties of the catalyst are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDXS). Electro-catalytic activity of AgCd alloy based electro-catalyst towards ORR is studied in alkaline medium by cyclic voltammetry and rotating ring disk electrode (RRDE) technique. Electrochemical in-situ FTIR measurements are also performed to identify the species generated during ORR process. Based on the results from electro-catalysis experiment, it is concluded that nano-alloyed AgCd electrodeposited on carbon paper shows excellent activity for ORR, following four electron pathways with H_2O_2 yield less than 15%. The combination of low cost of Ag and Cd, fast and facile method of its fabrication and higher activity towards ORR makes the AgCd electro-catalyst an attractive catalyst of choice for alkaline fuel cell.

Physical properties and characterization of Ag doped CdS thin films

International Nuclear Information System (INIS)

Shah, N.A.; Nazir, A.; Mahmood, W.; Syed, W.A.A.; Butt, S.; Ali, Z.; Maqsood, A.

2012-01-01

Highlights: ► CdS thin films were grown. ► By ion exchange, Ag was doped. ► Physical properties were investigated. - Abstract: Thin films of cadmium sulfide with very well defined preferential orientation and relatively high absorption coefficient were fabricated by thermal evaporation technique. The research is focused to the fabrication and characterization of the compositional data of CdS thin films obtained by using X-ray diffraction, scanning electron microscope along with energy dispersive X-ray spectroscopy. The optical properties were studied by using a UV-VIS-NIR spectrophotometer. The effects of silver-doping by ion exchange process on the properties of as-deposited CdS thin films have been investigated.

Photoelectric properties of thin films from the CdS-Ag2 S system

International Nuclear Information System (INIS)

Ristova-Lipanovikj, Mimoza

1996-01-01

Three different methods for preparation of thin films of CdS-Ag 2 S system are presented. Those methods are modified from the already existing methods of chemical deposition, and the method of spray pyrolysis, both widely utilized for preparation of wide range of binary, ternary and quaternary semiconductor thin films. The atomic absorption method was applied for quantitative analysis of the samples. The crystal structure of the thin films was studied by X-ray diffraction, while their morphology and the texture was analyzed from the microphotographs, taken on the samples by an optical microscope, in transmitted light. An extensive research was undertaken, to improve the crystallinity of the samples, by performing a post preparation thermal treatment. Photoelectric as well as some other physical properties were studied. VIS and NIR transmission spectra were recorded. The optical band gaps for various thin films containing different portions of Ag and Cd in the system, were evaluated. Spectral dependence of the photoconductivity was recorded. The optical band gaps were determined from the positions of the corresponding maxima of the photoconductivity. From the curves of the time relaxation of the photoconductivity, the carrier life times were calculates. Measurements of the thermal dependence of the resistivity on various samples were performed. Based on the extensive experimental research, the most convenient composition for PV application was selected. For the sake of comparison, two different types of PV cells were manufactured, Sn O 2 :F/CdS:Ag-Sn x S, and Sn O 2 :F/CdS-Sn x S, in order to study the influence of the silver content in the CdS. The plots of I-V and C-V characteristics are presented, and the parameters of the solar cells, were determined and taken in a relation with the content of the silver on the CdS. Finally, some directions of a possible future experimental and theoretical research in this field are given, based on the conclusions made. (author)

Physicochemical properties of new As2Se3–Ag4SSe–CdTe glasses

International Nuclear Information System (INIS)

Aljihmani, Lilia; Vassilev, Venceslav; Hristova-Vasileva, Temenuga; Fidancevska, Emilija

2009-01-01

Chalcogenide glasses from the As 2 Se 3 –Ag 4 SSe–CdTe system were synthesized. The basic physicochemical parameters such as density (d), microhardness (HV) and the temperatures glass transition Tg were measured. Compactness (C) and some thermomechanical characteristics such as volume (Vh) and formation energy (Eh) of micro-voids in the glassy network, as well as the module of elasticity (E) were calculated. A correlation between the composition and properties of the As 2 Se 3 –Ag 4 SSe–CdTe glasses was established and comprehensively discussed. Keywords: chalcogenide glasses, density, microhardness, compactness, elasticity modulus, thermomechanical characteristics

Pulse and gamma radiolytic studies of Ag, Cd and mixed clusters in aqueous solutions of carboxymethyl cellulose and gelatin

International Nuclear Information System (INIS)

Kapoor, Sudhir; Gopinathan, C.

1996-01-01

Pulse and gamma radiolytic studies in aqueous solutions of Ag, Cd and mixed clusters were carried out in carboxymethylcellulose (CMC) or gelatin. The reaction rate of e aq - with Ag + is lower in the presence of CMC or gelatin and oligomeric clusters of silver, Cd and mixed clusters get stabilized in their presence. (author). 2 refs., 2 figs

Durch intrinsische defekte induzierte uphill-diffusion von Ag und Cu in CdTe

CERN Document Server

Wagner, Frank

In the framework of the present thesis, the diffusion of Ag in CdTe was investigated by the radiotracer $^{111}$Ag. Thereby the focus was on the possibility to create a Ag flux from regions of low Ag concentration to regions of high Ag concentration (uphill diffusion). The experimentally observed diffusion profiles are explained in the framework of a thermodynamic diffusion model, taking into account the defect charge state and the defect interaction. The distribution of the charged defects produces a electric field, which leads to a drift of the charged defects. The experimental data are well explained assuming that Ag is incorporated interstitially and ionized (Agi$^{+}$). The Agi$^{+}$ concentration then reflects the profile of the Fermi level, which again is determined by the intrinsic defect distribution or, more precisely, the deviation from stoichiometry. On the basis of the experimental data it is possible to gather information on the thermodynamic properties of extrinsic as well as intrinsic defects....

Development of aluminum (Al5083)-clad ternary Ag-In-Cd alloy for JSNS decoupled moderator

International Nuclear Information System (INIS)

Teshigawara, M.; Harada, M.; Saito, S.; Oikawa, K.; Maekawa, F.; Futakawa, M.; Kikuchi, K.; Kato, T.; Ikeda, Y.; Naoe, T.; Koyama, T.; Ooi, T.; Zherebtsov, S.; Kawai, M.; Kurishita, H.; Konashi, K.

2006-01-01

To develop Ag (silver)-In (indium)-Cd (cadmium) alloy decoupler, a method is needed to bond the decoupler between Al alloy (Al5083) and the ternary Ag-In-Cd alloy. We found that a better HIP condition was temperature, pressure and holding time at 803 K, 100 MPa and 10 min. for small test pieces (φ22 mm in dia. x 6 mm in height). Hardened layer due to the formation of AlAg 2 was found in the bonding layer, however, the rupture strength of the bonding layer is more than 30 MPa, the calculated design stress. Bonding tests of a large size piece (200 x 200 x 30 mm 3 ), which simulated the real scale, were also performed according to the results of small size tests. The result also gave good bonding and enough required-mechanical-strength

On one possibility for application of new thermoelectric materials based on Ag2Te

International Nuclear Information System (INIS)

Vassilev, Venceslav; Parvanov, Svetlin; Vachkov, Valeri

2011-01-01

The thermoelectric characteristics of Ag 2 Te and Ag 1,84 Cd 0,08 Te (solid solution based on Ag 2 Te) are investigated and analyzed. The main thermoelectric characteristics of the solid solution: α=118 μV/K; σ = 2230 S/cm and = 2,45.10 -2 W/(cm.K) ensure coefficient of thermoelectric efficiency z = 1,27. 10-3 K -1 (at 300 ), which increases this of the Ag 2 Te. A composition for commutation material is developed, which connects the N- and the P-branches of a single thermo element (52 wt. % In + 48 wt. % Sn) with melting temperature of 390 K. The possibility for application of the Ag 1,84 Cd 0,08 Te solid solution as N-branch of a thermo element in combination with the solid solution Bi 0,5 Sb 1,5 Te 3 (P-branch) is investigated. The thermo element guarantees values of z from 0,71.10 -3 to 1,27.10 -3 K -1 in the temperature interval 250 - 350 . The maximum z value is registered at 300 K (z = 1,27.10 -3 K -1 ). Keywords: Silver telluride, Solid solutions, Thermoelectric properties, Thermo element

Separation procedure for the determination of Ag, Cd, Hg and Zn in biological material by radiochemical neutron activation analysis

Energy Technology Data Exchange (ETDEWEB)

Haas, H F; Krivan, V

1986-05-01

A simple separation procedure for the determination of Ag, Au, Cd, Hg and Zn in biological material by radiochemical neutron activation analysis was developed. It enables the separation of the indicator radionuclides sup(110m)Ag, /sup 198/Au, /sup 115/Cd, /sup 203/Hg and /sup 65/Zn in a group with yields >99% and is well suited for the separation of /sup 203/Hg from /sup 75/Se and /sup 65/Zn from /sup 46/Sc. The separation of these radionuclides is often necessary because of the occurrence of instrumental interferences in the instrumental neutron activation analysis. Simultaneously, the limits of detection for Ag, Au and Cd can significantly be improved. The method is based on the decomposition of the sample in the mixture of HNO/sub 3//HCl/H/sub 2/O/sub 2/ and on the separation of Ag, Au, Cd, Hg and Zn on Dowex 1X8 from a sample solution being 1.5 M with HCl. The applicability of this method is demonstrated by the analysis of lichens and several kinds of fungi. For the experimental conditions used, the limits of detection are of the order of magnitude of 10 ng/g.

Ag nanoclusters could efficiently quench the photoresponse of CdS quantum dots for novel energy transfer-based photoelectrochemical bioanalysis.

Science.gov (United States)

Zhang, Ling; Sun, Yue; Liang, Yan-Yu; He, Jian-Ping; Zhao, Wei-Wei; Xu, Jing-Juan; Chen, Hong-Yuan

2016-11-15

Herein the influence of ultrasmall Ag nanoclusters (Ag NCs) against CdS quantum dots (QDs) in a photoelectrochemical (PEC) nanosystem was exploited for the first time, based on which a novel PEC bioanalysis was successfully developed via the efficient quenching effect of Ag NCs against the CdS QDs. In a model system, DNA assay was achieved by using molecular beacon (MB) probes anchored on a CdS QDs modified electrode, and the MB probes contain two segments that can hybridize with both target DNA sequence and the label of DNA encapsulated Ag NCs. After the MB probe was unfolded by the target DNA sequence, the labels of oligonucleotide encapsulated Ag NCs would be brought in close proximity to the CdS QDs electrode surface, and efficient photocurrent quenching of QDs could be resulted from an energy transfer process that originated from NCs. Thus, by monitoring the attenuation in the photocurrent signal, an elegant and sensitive PEC DNA bioanalysis could be accomplished. The developed biosensor displayed a linear range from 1.0pM to 10nM and the detection limit was experimentally found to be of 0.3pM. This work presents a feasible signaling principle that could act as a common basis for general PEC bioanalysis development. Copyright © 2016 Elsevier B.V. All rights reserved.

AgSbSe2 and AgSb(S,Se)2 thin films for photovoltaic applications

International Nuclear Information System (INIS)

Garza, J.G.; Shaji, S.; Rodriguez, A.C.; Das Roy, T.K.; Krishnan, B.

2011-01-01

Silver antimony selenide (AgSbSe 2 ) thin films were prepared by heating sequentially deposited multilayers of antimony sulphide (Sb 2 S 3 ), silver selenide (Ag 2 Se), selenium (Se) and silver (Ag). Sb 2 S 3 thin film was prepared from a chemical bath containing SbCl 3 and Na 2 S 2 O 3 , Ag 2 Se from a solution containing AgNO 3 and Na 2 SeSO 3 and Se thin films from an acidified solution of Na 2 SeSO 3 , at room temperature on glass substrates. Ag thin film was deposited by thermal evaporation. The annealing temperature was 350 deg. C in vacuum (10 -3 Torr) for 1 h. X-ray diffraction analysis showed that the thin films formed were polycrystalline AgSbSe 2 or AgSb(S,Se) 2 depending on selenium content in the precursor films. Morphology and elemental analysis of these films were done using scanning electron microscopy and energy dispersive X-ray spectroscopy. Optical band gap was evaluated from the UV-visible absorption spectra of these films. Electrical characterizations were done using Hall effect and photocurrent measurements. A photovoltaic structure: glass/ITO/CdS/AgSbSe 2 /Al was formed, in which CdS was deposited by chemical bath deposition. J-V characteristics of this structure showed V oc = 435 mV and J sc = 0.08 mA/cm 2 under illumination using a tungsten halogen lamp. Preparation of a photovoltaic structure using AgSbSe 2 as an absorber material by a non-toxic selenization process is achieved.

Influence of reactive sulfide (AVS) and supplementary food on Ag, Cd and Zn bioaccumulation in the marine polychaete Neanthes arenaceodentata

Science.gov (United States)

Lee, J.-S.; Lee, B.-G.; Yoo, H.; Koh, C.-H.; Luoma, S.N.

2001-01-01

A laboratory bioassay determined the relative contribution of various pathways of Ag, Cd and Zn bioaccumulation in the marine polychaete Neanthes arenaceodentata exposed to moderately contaminated sediments. Juvenile worms were exposed for 25 d to experimental sediments containing 5 different reactive sulfide (acid volatile sulfides, AVS) concentrations (1 to 30 ??mol g-1), but with constant Ag, Cd, and Zn concentrations of 0.1, 0.1 and 7 ??mol g-1, respectively. The sediments were supplemented with contaminated food (TetraMin??) containing 3 levels of Ag-Cd-Zn (uncontaminated, 1?? or 5??1 metal concentrations in the contaminated sediment). The results suggest that bioaccumulation of Ag, Cd and Zn in the worms occurred predominantly from ingestion of contaminated sediments and contaminated supplementary food. AVS or dissolved metals (in porewater and overlying water) had a minor effect on bioaccumulation of the 3 metals in most of the treatments. The contribution to uptake from the dissolved source was most important in the most oxic sediments, with maximum contributions of 8% for Ag, 30% for Cd and 20% for Zn bioaccumulation. Sediment bioassays where uncontaminated supplemental food is added could seriously underestimate metal exposures in an equilibrated system; N. arenaceodentata feeding on uncontaminated food would be exposed to 40-60% less metal than if the food source was equilibrated (as occurs in nature). Overall, the results show that pathways of metal exposure are dynamically linked in contaminated sediments and shift as external geochemical characteristics and internal biological attributes vary.

Ag{sub 2}CdI{sub 4}: Synthesis, characterization and investigation the strain lattice and grain size

Energy Technology Data Exchange (ETDEWEB)

Ghanbari, Mojgan [Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box 87317-51167, I.R. (Iran, Islamic Republic of); Gholamrezaei, Sousan [Young Researchers Club, Arak Branch, Islamic Azad University, Arak (Iran, Islamic Republic of); Salavati-Niasari, Masoud, E-mail: salavati@kashanu.ac.ir [Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box 87317-51167, I.R. (Iran, Islamic Republic of)

2016-05-15

In this work the Ag{sub 2}CdI{sub 4} nanostructures have been synthesized via a solid state reaction from reaction of AgI and CdI{sub 2} as precursors. The effect of the mole ratio of precursors, time and temperature of reaction has been optimized to achieve the best product on morphology and purity. Nanostructures have been characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman (FT-IR) techniques, X-ray energy dispersive spectroscopy (EDS) and Ultraviolet spectroscopy (UVvis). The XRD patterns of nanostructures have been used to estimate the grain sizes and strain lattice. Grain size of nanostructures is in range of 5–17 nm and the strain of lattice is changed in range of 0.0024–0.014. The band gap of these nanostructures has been estimated by DRS spectrum about 5.4 eV. Raman spectroscopy has been confirmed the XRD results and show that the Ag{sub 2}CdI{sub 4} nanostructures have been synthesized. SEM and TEM images have been used for investigation of morphology of product. Results show that the best morphology and purity have been achieved in 12 h and 200 °C in 1:1 mol ratio of precursors. - Highlights: • Ag{sub 2}CdI{sub 4} nanostructures have been synthesized by low temperature solid state method. • The reaction has been optimized for purity, morphology, and grain size and strain lattice. • Effective parameters have been optimized such as time, temperature and mole ratio.

Mass measurements on short-lived Cd and Ag nuclides at the online mass spectrometer ISOLTRAP

International Nuclear Information System (INIS)

Breitenfeldt, Martin

2009-01-01

In the present work, mass determinations of the eleven neutron-deficient nuclides 99-109 Cd, of ten neutron-rich silver nuclides 112,114-121,123 Ag, and seven neutron-rich cadmium nuclides 114,120,122-124,126,128 Cd are reported. Due to the clean production of the neutron-deficient nuclides it was possible to reduce the experimental uncertainties down to 2 keV, whereas the measurements of neutron-rich nuclides were hampered by the presence of contaminations from more stable In and Cs nuclides. In the case of 99 Cd and 123 Ag the masses were determined for the first time and for the other nuclides the mass uncertainties could be reduced by up to a factor of 50 as in the case of 100 Cd. In the case of a potential isomeric mixture as for 115,117,119 Ag and 123 Cd, where no assignment to either the ground state or the excited state was possible, the experimental results were adjusted accordingly. Afterwards all results were included in the framework of the atomic-mass evaluation and thus linked and compared with other experimental data. In the case of a potential isomeric mixture as for 115,117,119 Ag and 123 Cd, where no assignment to either the ground state or the excited state was possible, the experimental results were adjusted accordingly. Afterwards all results were included in the framework of the atomic-mass evaluation and thus linked and compared with other experimental data. In the case of the neutron-deficient Cd nuclides a conflict between the mass values obtained in the present work and those published by the JYFLTRAP group [EEH + ] could be solved by performing an atomic-mass evaluation. Thus, it was revealed that reason for the conflict was a different value of the JYFLTRAP reference mass 96 Mo. Furthermore, a reduction of the mass uncertainty and a slight increase of the mass of 100 In were obtained. These mass measurements are an important step towards an understanding of the physics of the rp process that will enable a more reliable determination of

The matrix effect study in the spectrographic analysis of rare earth elements. Pt. 1. The influence of Sn, Pb, Sb, Bi, Cu, Ag, Zn and Cd on the spectral lines intensity of Y, La, Ce, Pr, Nd and Sm in the current arc exciting between C-electrodes

International Nuclear Information System (INIS)

Wysocka-Lisek, J.; Paszkowska, B.; Mularczyk, K.

1976-01-01

In the beginning the influence of Sn, Pb, Sb, Bi, Cu, Ag, Zn and Cd on the light rare earth spectral lines using Ni as the internal standard, during the intermittent current arc excitation between C-electrodes was studied. On the basis of the spectral lines intensity measurements, it was stated that one may apply the addition of Ni as the internal standard by the quantitative determination of Sn, Pb, Sb, Bi, Zn and Cd in the light rare earth mixtures with one of the above. Also a great influence of the presence of the individually studied metal was observed on the spectral line intensity of rare earth elements and nickel. The differences of the thermo-chemical reactions nature between excited elements and the carbon of the electrodes may cause that influence. (author)

Process development for fabrication of Ag-15% In-5% Cd alloys and rods for the control rods of IPEN critical unit

International Nuclear Information System (INIS)

Figueredo, A.M. de.

1985-12-01

The development of two process at the Nuclear and Energetic Research Institute (IPEN-Brazil) are described. - the production of Ag-15% In-5%. Cd alloys with nuclear grade. The fabrication of rods from Ag-15% In-5% Cd alloy for use at the critical unit. The methods for quality control of alloy and rod are presented, and main problems are identified. (C.G.C.)

Ag-doped CdO nanocatalysts: Preparation, characterization and catechol oxidase activity

Science.gov (United States)

El-Kemary, Maged; El-Mehasseb, Ibrahim; El-Shamy, Hany

2018-06-01

Silver doped cadmium oxide (Ag/CdO) nanoparticles with an average size of 41 nm have been successfully synthesized via thermal decomposition and liquid impregnation technique. The structural characterization has been performed by using several spectroscopic techniques, e.g., X-ray diffraction (XRD), scanning electron microscopy (SEM) and fourier-transform infrared (FT-IR). The catechol oxidase has been studied by UV-visible absorption spectroscopy and fourier-transform infrared as well as the mechanism has been assured by cyclic voltammetry and fluorescence spectroscopy. The results indicate that the oxidation does not occur in the presence of unsupported cadmium oxide particles by silver and in the same time, the catechol oxidase activity of silver doped CdO nanoparticles were improved by about three orders of magnitude than silver ions.

Mass measurements on short-lived Cd and Ag nuclides at the online mass spectrometer ISOLTRAP

Energy Technology Data Exchange (ETDEWEB)

Breitenfeldt, Martin

2009-07-03

In the present work, mass determinations of the eleven neutron-deficient nuclides {sup 99-109}Cd, of ten neutron-rich silver nuclides {sup 112,114-121,123}Ag, and seven neutron-rich cadmium nuclides {sup 114,120,122-124,126,128}Cd are reported. Due to the clean production of the neutron-deficient nuclides it was possible to reduce the experimental uncertainties down to 2 keV, whereas the measurements of neutron-rich nuclides were hampered by the presence of contaminations from more stable In and Cs nuclides. In the case of {sup 99}Cd and {sup 123}Ag the masses were determined for the first time and for the other nuclides the mass uncertainties could be reduced by up to a factor of 50 as in the case of {sup 100}Cd. In the case of a potential isomeric mixture as for {sup 115,117,119}Ag and {sup 123}Cd, where no assignment to either the ground state or the excited state was possible, the experimental results were adjusted accordingly. Afterwards all results were included in the framework of the atomic-mass evaluation and thus linked and compared with other experimental data. In the case of a potential isomeric mixture as for {sup 115,117,119}Ag and {sup 123}Cd, where no assignment to either the ground state or the excited state was possible, the experimental results were adjusted accordingly. Afterwards all results were included in the framework of the atomic-mass evaluation and thus linked and compared with other experimental data. In the case of the neutron-deficient Cd nuclides a conflict between the mass values obtained in the present work and those published by the JYFLTRAP group [EEH{sup +}] could be solved by performing an atomic-mass evaluation. Thus, it was revealed that reason for the conflict was a different value of the JYFLTRAP reference mass {sup 96}Mo. Furthermore, a reduction of the mass uncertainty and a slight increase of the mass of {sup 100}In were obtained. These mass measurements are an important step towards an understanding of the physics of

High activity of Ag-doped Cd0.1Zn0.9S photocatalyst prepared by the hydrothermal method for hydrogen production under visible-light irradiation

Directory of Open Access Journals (Sweden)

Leny Yuliati

2014-05-01

Full Text Available Background: The hydrothermal method was used as a new approach to prepare a series of Ag-doped Cd0.1Zn0.9S photocatalysts. The effect of Ag doping on the properties and photocatalytic activity of Cd0.1Zn0.9S was studied for the hydrogen production from water reduction under visible light irradiation.Results: Compared to the series prepared by the co-precipitation method, samples prepared by the hydrothermal method performed with a better photocatalytic activity. The sample with the optimum amount of Ag doping showed the highest hydrogen production rate of 3.91 mmol/h, which was 1.7 times higher than that of undoped Cd0.1Zn0.9S. With the Ag doping, a red shift in the optical response was observed, leading to a larger portion of the visible light absorption than that of without doping. In addition to the larger absorption in the visible-light region, the increase in photocatalytic activity of samples with Ag doping may also come from the Ag species facilitating electron–hole separation.Conclusion: This study demonstrated that Ag doping is a promising way to enhance the activity of Cd0.1Zn0.9S photocatalyst.

Simultaneous determination of Hg(II)-Ag(I)-Cd(II) by conductometric titration using the formation of ternary complex

International Nuclear Information System (INIS)

Hayashida, Ichiro; Yoshida, Hitoshi; Taga, Mitsuhiko; Hikime, Seiichiro

1979-01-01

A conductometric determination of Hg(II), Ag(I) and Cd(II) was carried out by using the insoluble ternary complex formation of the metal ions with iodide ion in the presence of 1,10-phenanthroline (phen). Recommended procedure is as follows; An aliquot of sample solution containing (14 -- 29) mg of Hg(II), (8 -- 16) mg of Ag(I), and (9 -- 17) mg of Cd(II) transfered into a 100 ml beaker. Add to acetate buffer and stoichiometric amounts of phen (40% ethanol-water solution). Amounts of nitrate ion which was estimated separately by other titration with 0.1 M Ag(phen) 2 complex (40% ethanol-water solution) are adjusted in the range of (4.0 -- 6.0) mM. The sample solution is titrated with 0.1 M KI standard solution at the rate of 0.20 ml/min or less. The titration curve showed three end-points corresponding to the formation of (1) Hg(phen) 2 I 2 , (2) Ag(phen)I, and (3) Cd(phen) 2 I 2 . The relative standard deviation was less than 0.8%, when the pH value was controlled at 4.0 -- 4.5 (acetate buffer) and the nitrate concentration was adjusted in the range of (4.0 -- 6.0)mM. The effect of diverse ions on the determination was also investigated in detail. (author)

Cd induced redistribution of elements within leaves of the Cd/Zn hyperaccumulator Thlaspi praecox as revealed by micro-PIXE

International Nuclear Information System (INIS)

Pongrac, Paula; Vogel-Mikus, Katarina; Vavpetic, Primoz; Tratnik, Janja; Regvar, Marjana; Simcic, Jurij; Grlj, Natasa; Pelicon, Primoz

2010-01-01

A detailed localisation of elements within leaf tissues of hydroponically grown Cd/Zn hyperaccumulator Thlaspi praecox (Brassicaceae) was determined by micro-PIXE at Jozef Stefan Institute (Ljubljana, Slovenia) in order to study accumulation patterns of Cd and other elements in the case of a single metal (Cd) pollution. Plants were treated with increasing concentrations of Cd in the solution (0 (control), 1, 10 and 100 μM). As expected, concentration of Cd in the leaves gradually increased with Cd concentration in the solution. In order to reveal the main Cd storage compartment space within the leaves a relative element distribution (pool) was calculated based on concentrations of elements in specific leaf tissues and their weight portions. Where present at detectable levels, Cd accumulated in the epidermal tissues (at 10 μM), but the contribution of epidermal pool decreased with increasing Cd concentration in solution (at 100 μM). The opposite was observed for the mesophyll pool. In addition, in Cd treated plants, a significant decrease in mesophyll Fe pool and an increase in the epidermal Fe pool were observed. Similar effect was seen for Mn pool at 100 μM Cd treatment accompanied by increasing Zn epidermal pool with increasing Cd in nutrient solution. Altogether these results indicate repartitioning of essential mesophyll cation pools (e.g., Fe, Mn and possibly Zn) when increasing Cd contents, that are instead more intensively stored in the epidermal cells. These results confirmed micro-PIXE as effective and powerful technique providing essential information on metal localisation, repartitioning and major elemental stores in plants on the tissue levels that were not accessible using classical analytical techniques and thus complementing our current understanding of plant metal tolerance mechanisms as a whole.

CD4/CD8/Dendritic cell complexes in the spleen: CD8+ T cells can directly bind CD4+ T cells and modulate their response

Science.gov (United States)

Barinov, Aleksandr; Galgano, Alessia; Krenn, Gerald; Tanchot, Corinne; Vasseur, Florence

2017-01-01

CD4+ T cell help to CD8+ T cell responses requires that CD4+ and CD8+ T cells interact with the same antigen presenting dendritic cell (Ag+DC), but it remains controversial whether helper signals are delivered indirectly through a licensed DC and/or involve direct CD4+/CD8+ T cell contacts and/or the formation of ternary complexes. We here describe the first in vivo imaging of the intact spleen, aiming to evaluate the first interactions between antigen-specific CD4+, CD8+ T cells and Ag+DCs. We show that in contrast to CD4+ T cells which form transient contacts with Ag+DC, CD8+ T cells form immediate stable contacts and activate the Ag+DC, acquire fragments of the DC membranes by trogocytosis, leading to their acquisition of some of the DC properties. They express MHC class II, and become able to present the specific Marilyn peptide to naïve Marilyn CD4+ T cells, inducing their extensive division. In vivo, these CD8+ T cells form direct stable contacts with motile naïve CD4+ T cells, recruiting them to Ag+DC binding and to the formation of ternary complexes, where CD4+ and CD8+ T cells interact with the DC and with one another. The presence of CD8+ T cells during in vivo immune responses leads to the early activation and up-regulation of multiple functions by CD4+ T lymphocytes. Thus, while CD4+ T cell help is important to CD8+ T cell responses, CD8+ T cells can interact directly with naïve CD4+ T cells impacting their recruitment and differentiation. PMID:28686740

Geochemistry of the Patricia Zn-Pb-Ag Deposit (paguanta, NE Chile)

Science.gov (United States)

Chinchilla Benavides, D.; Merinero Palomares, R.; Piña García, R.; Ortega Menor, L.; Lunar Hernández, R.

2013-12-01

The Patricia Zn-Pb-Ag ore deposit is located within the Paguanta mining project, situated at the northern end of the Andean Oligocene Porphyry Copper Belt of Chile. The sulfide mineralization occurs as W-E oriented veins hosted in volcanic rocks, mainly andesite (pyroclastic, ash and lavas), of Upper Cretaceous to Middle Tertiary age. The ore mineralogy (obtained by EMPA analyses) comprises in order of abundance, pyrite, sphalerite (5.5 - 10.89 wt % Fe, 9.8-19 % molar FeS and 0.52 wt % Cd), galena, arsenopyrite, chalcopyrite and Ag-bearing sulfosalts. The veins show a zoned and banded internal structure with pyrite at the edges and sphalerite in the center. The Ag occurs mostly as Ag-Cu-Sb sulfosalts, in order of abundance: series freibergite - argentotennantite -polybasite and stephanite. Other minor Ag phases such as argentite, pyrargirite and diaphorite were also identified. These Ag phases are typically associated with the base-metal sulfides. Freibergite occurs filling voids within sphalerite, chalcopyrite and at the contact between sphalerite and galena. Polybasite, stephanite, pyrargirite and argentite are mostly in close association with freibergite. In the case of diaphorite, it commonly occurs filling voids between galena crystals or as inclusions within galena. Some minor Ag-bearing sulfosalts are also identified between pyrite crystals. The alteration minerals are dominated by chlorite, illite and kaolinite. The gangue minerals consist of quartz and carbonates identified by XRD as kutnahorite. We obtained linear correlation statistically significant only for Ag, As Au, Cd, Cu, Pb, Sb and Zn and therefore we generated an enhanced scatter plot matrix of these elements. Bulk rock analyses (ICP/MS and XRF) of drill cores show that Ag is strongly and positively correlated with Pb and As, moderately with Cd, Sb, Au and Zn and weakly with Cu, while Au is moderately and positively correlated with Ag, As, Cd, Sb and Zn and weakly with Cu and Pb. These results

AgSbSe{sub 2} and AgSb(S,Se){sub 2} thin films for photovoltaic applications

Energy Technology Data Exchange (ETDEWEB)

Garza, J.G. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Shaji, S. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Facultad de Ingenieria Mecanica y Electrica, CIIDIT - Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico); Rodriguez, A.C.; Das Roy, T.K. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Krishnan, B., E-mail: kbindu_k@yahoo.com [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon (Mexico); Facultad de Ingenieria Mecanica y Electrica, CIIDIT - Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico)

2011-10-01

Silver antimony selenide (AgSbSe{sub 2}) thin films were prepared by heating sequentially deposited multilayers of antimony sulphide (Sb{sub 2}S{sub 3}), silver selenide (Ag{sub 2}Se), selenium (Se) and silver (Ag). Sb{sub 2}S{sub 3} thin film was prepared from a chemical bath containing SbCl{sub 3} and Na{sub 2}S{sub 2}O{sub 3}, Ag{sub 2}Se from a solution containing AgNO{sub 3} and Na{sub 2}SeSO{sub 3} and Se thin films from an acidified solution of Na{sub 2}SeSO{sub 3}, at room temperature on glass substrates. Ag thin film was deposited by thermal evaporation. The annealing temperature was 350 deg. C in vacuum (10{sup -3} Torr) for 1 h. X-ray diffraction analysis showed that the thin films formed were polycrystalline AgSbSe{sub 2} or AgSb(S,Se){sub 2} depending on selenium content in the precursor films. Morphology and elemental analysis of these films were done using scanning electron microscopy and energy dispersive X-ray spectroscopy. Optical band gap was evaluated from the UV-visible absorption spectra of these films. Electrical characterizations were done using Hall effect and photocurrent measurements. A photovoltaic structure: glass/ITO/CdS/AgSbSe{sub 2}/Al was formed, in which CdS was deposited by chemical bath deposition. J-V characteristics of this structure showed V{sub oc} = 435 mV and J{sub sc} = 0.08 mA/cm{sup 2} under illumination using a tungsten halogen lamp. Preparation of a photovoltaic structure using AgSbSe{sub 2} as an absorber material by a non-toxic selenization process is achieved.

Micro-PIXE studies of elemental distribution in Cd-accumulating Brassica juncea L

International Nuclear Information System (INIS)

Schneider, Thorsten; Haag-Kerwer, Angela; Maetz, Mischa; Niecke, Manfred; Povh, Bogdan; Rausch, Thomas; Schuessler, Arthur

1999-01-01

Brassica juncea L. is a high biomass producing crop plant, being able to accumulate Cd and other heavy metals in their roots and shoots. It is a good candidate for efficient phytoextraction of heavy metals - such as Cd - from polluted soils. PIXE and STIM analyses were applied to investigate Cd-uptake in roots and the resulting effects on the elemental distribution of Cd stressed plants. The axial distribution of trace elements as a function of distance from the root tip as well as the radial distribution within cross-sections were analysed. The results are compared with the elemental distribution in control plants

Micro-PIXE studies of elemental distribution in Cd-accumulating Brassica juncea L.

Science.gov (United States)

Schneider, Thorsten; Haag-Kerwer, Angela; Maetz, Mischa; Niecke, Manfred; Povh, Bogdan; Rausch, Thomas; Schüßler, Arthur

1999-10-01

Brassica juncea L. is a high biomass producing crop plant, being able to accumulate Cd and other heavy metals in their roots and shoots. It is a good candidate for efficient phytoextraction of heavy metals - such as Cd - from polluted soils. PIXE and STIM analyses were applied to investigate Cd-uptake in roots and the resulting effects on the elemental distribution of Cd stressed plants. The axial distribution of trace elements as a function of distance from the root tip as well as the radial distribution within cross-sections were analysed. The results are compared with the elemental distribution in control plants.

Micro-PIXE studies of elemental distribution in Cd-accumulating Brassica juncea L

Energy Technology Data Exchange (ETDEWEB)

Schneider, Thorsten E-mail: thorsten.schneider@mpi-hd.mpg.de; Haag-Kerwer, Angela; Maetz, Mischa; Niecke, Manfred; Povh, Bogdan; Rausch, Thomas; Schuessler, Arthur

1999-09-02

Brassica juncea L. is a high biomass producing crop plant, being able to accumulate Cd and other heavy metals in their roots and shoots. It is a good candidate for efficient phytoextraction of heavy metals - such as Cd - from polluted soils. PIXE and STIM analyses were applied to investigate Cd-uptake in roots and the resulting effects on the elemental distribution of Cd stressed plants. The axial distribution of trace elements as a function of distance from the root tip as well as the radial distribution within cross-sections were analysed. The results are compared with the elemental distribution in control plants.

First cross-section measurements of the reactions Ag,109107(p ,γ )Cd,110108 at energies relevant to the p process

Science.gov (United States)

Khaliel, A.; Mertzimekis, T. J.; Asimakopoulou, E.-M.; Kanellakopoulos, A.; Lagaki, V.; Psaltis, A.; Psyrra, I.; Mavrommatis, E.

2017-09-01

Background: One of the primary objectives of the field of Nuclear Astrophysics is the study of the elemental and isotopic abundances in the universe. Although significant progress has been made in understanding the mechanisms behind the production of a large number of nuclides in the isotopic chart, there are still many open questions regarding a number of neutron-deficient nuclei, the p nuclei. To that end, experimentally deduced nuclear reaction cross sections can provide invaluable input to astrophysical models. Purpose: The reactions Ag,109107(p ,γ )Cd,110108 have been studied at energies inside the astrophysically relevant energy window in an attempt to provide experimental data required for the testing of reaction-rate predictions in terms of the statistical model of Hauser-Feshbach around the p nucleus 108Cd. Methods: The experiments were performed with in-beam γ -ray spectroscopy with proton beams accelerated by the Tandem Van de Graaff Accelerator at NCSR "Demokritos" impinging a target of natural silver. A set of high-purity germanium detectors was employed to record the emitted radiation. Results: A first set of total cross-section measurements in radiative proton-capture reactions involving Ag,109107, producing the p -nucleus 108Cd, inside the astrophysically relevant energy window is reported. The experimental results are compared to theoretical calculations, using talys. An overall good agreement between the data and the theoretical calculations has been found. Conclusions: The results reported in this work add new information to the relatively unexplored p process. The present measurements can serve as a reference point in understanding the nuclear parameters in the related astrophysical environments and for future theoretical modeling and experimental works.

Size-controlled sensitivity and selectivity for the fluorometric detection of Ag+ by homocysteine capped CdTe quantum dots

International Nuclear Information System (INIS)

Jiao, Hangzhou; Liang, Zhenhua; Peng, Guihua; Zhang, Ling; Lin, Hengwei

2014-01-01

We have synthesized water dispersible CdTe quantum dots (QDs) in different sizes and with various capping reagents, and have studied the effects of their size on the sensitivity and selectivity in the fluorometric determination of metal ions, particularly of silver(I). It is found that an increase in the particle size of homocysteine-capped CdTe QDs from 1.7 nm to 3.3 nm and to 3.7 nm enhances both the sensitivity and selectivity of the determination of Ag(I) to give an ultimate limit of detection as low as 8.3 nM. This effect can partially be explained by the better passivation of surface traps on smaller sized QDs via adsorption of Ag(I), thereby decreasing the apparent detection efficiency. In addition, the presence of CdS in the CdTe QDs is likely to play a role. The study demonstrates that an improvement in sensing performance is accomplished by using QDs of fine-tuned particle sizes. Such effects are likely also to occur with other QD-based optical probes. (author)

Syntheses, crystal structures and fluorescent properties of Cd(II), Hg(II) and Ag(I) coordination polymers constructed from 1H-1,2,4-triazole-1-acetic acid

International Nuclear Information System (INIS)

Ding Degang; Xie Lixia; Fan Yaoting; Hou Hongwei; Xu Yan

2009-01-01

Three new d 10 coordination polymers, namely [Cd(taa)Cl] n 1, [Hg(taa)Cl] n 2, and [Ag 1.5 (taa)(NO 3 ) 0.5 ] n 3 (taa=1H-1,2,4-triazole-1-acatate anion) have been prepared and characterized by elemental analysis, IR, and single crystal X-ray diffraction. Compound 1 consists of two-dimensional layers constructed by carboxyl-linked helical chains, which are further linked through carboxyl group to generate a unique 3D open framework. Topological analysis reveals that the structure of 1 can be classified as an unprecedented (3,8)-connected network with the Schlaefli symbol (4.5 2 ) 2 (4 2 .5 8 .6 14 .7 3 .8). Compound 2 manifests a doubly interpenetrated decorated α-polonium cubic network with the Schlaefli symbol of (4 10 .6 2 .8 3 ). Compound 3 consists of 2D puckered layers made up of Ag centers and taa - bridges. In addition, all of these compounds are photoluminescent in the solid state with spectra that closely resemble those of the ligand precursor. - Graphical abstract: Three new compounds based on 1H-1,2,4-triazole-1-acetic acid and Cd(II), Hg(II) and Ag(I) salts display luminescent properties and may be potential candidates for luminescent materials.

Ag/AgCl nanoparticles-modified CdSnO3·3H2O nanocubes photocatalyst for the degradation of methyl orange and antibiotics under visible light irradiation.

Science.gov (United States)

Yang, Shi-Feng; Niu, Cheng-Gang; Huang, Da-Wei; Zhang, Huan; Zeng, Guang-Ming

2017-11-01

CdSnO 3 ·3H 2 O (CSH) nanocubes modified with Ag/AgCl nanoparticles were constructed via the ultrasonic-assisted precipitation-photoreduction method. The obtained samples were characterized using various analytical techniques. Methyl orange (MO), tetracycline (TC), and oxytetracycline hydrochloride (OTC-HCl) were degraded as target pollutants under visible light irradiation to evaluate the photocatalytic activity of the as-prepared samples. Compared with pure CSH and Ag/AgCl nanoparticles, the developed composite of which 5mL of AgNO 3 was added on the synthesis, labelled as 5-Ag/AgCl/CSH, occupied the best photocatalytic activity. The corresponding degradation rate for MO was 94% within 40min. 94% of TC and 90% of OTC-HCl were also degraded by 5-Ag/AgCl/CSH catalyst within 60min, respectively. The enhanced photocatalytic activity might arise from the surface plasmon resonance effect of Ag/AgCl nanoparticles and efficient separation of photogenerated electron-hole pairs. Meanwhile, a possible photocatalytic mechanism over 5-Ag/AgCl/CSH sample was proposed based on the experiment and theoretical analysis. Copyright © 2017. Published by Elsevier Inc.

Photoinduced transformations of optical properties of CdSe and Ag-In-S nanocrystals embedded in the films of polyvinyl alcohol

Directory of Open Access Journals (Sweden)

Tetyana Kryshtab

2016-06-01

Full Text Available The results of investigation of photostability of the composites of CdSe and Ag-In-S nanocrystals (NCs embedded in the films of polyvinyl alcohol (PVA are presented. The films were studied by photoluminescence (PL, optical absorption, micro-Raman and X-ray diffraction methods. It is found that heating of the films to 100 °C promotes PVA crystallization and stimulates an increase of the PL intensity for the NCs of both types. The latter effect is ascribed mainly to the improvement of NC surface passivation by functional groups of PVA. The illumination with the 409-nm LED’s light enhances PL intensity for CdSe NCs and decreases it for Ag-In-S NCs as well as results in the darkening of the films. The color of the Ag-In-S-PVA film restores with time, while the change of the optical properties of the CdSe-PVA composite is irreversible. The possible mechanisms of the revealed effects, such as structural transformations at NC/PVA interface as well as the formation of new light-absorbing species are discussed.

Chiral recognition of phenylglycinol enantiomers based on N-acetyl-L-cysteine capped CdTe quantum dots in the presence of Ag+

Science.gov (United States)

Guo, Yuan; Zeng, Xiaoqing; Yuan, Haiyan; Huang, Yunmei; Zhao, Yanmei; Wu, Huan; Yang, Jidong

2017-08-01

In this study, a novel method for chiral recognition of phenylglycinol (PG) enantiomers was proposed. Firstly, water-soluble N-acetyl-L-cysteine (NALC)-capped CdTe quantum dots (QDs) were synthesized and experiment showed that the fluorescence intensity of the reaction system slightly enhancement when added PG enantiomers to NALC-capped CdTe quantum dots (QDs), but the R-PG and S-PG could not be distinguished. Secondly, when there was Ag+ presence in the reaction system, the experiment result was extremely interesting, the PG enantiomers cloud make NALC-capped CdTe QDs produce different fluorescence signal, in which the fluorescence of S-PG + Ag+ + NALC-CdTe system was significantly enhanced, and the fluorescence of R-PG + Ag+ + NALC-CdTe system was markedly decreased. Thirdly, all the enhanced and decreased of the fluorescence intensity were directly proportional to the concentration of R-PG and S-PG in the linearly range 10- 5-10- 7 mol·L- 1, respectively. So, the new method for simultaneous determination of the PG enantiomers was built too. The experiment result of the method was satisfactory with the detection limit of PG can reached 10- 7 mol·L- 1 and the related coefficient of S-PG and R-PG are 0.995 and 0.980, respectively. The method was highly sensitive, selective and had wider detection range compared with other methods.

Study of the efficiency of AgCl, In2O3, Ga2O3, NaF, LiF and SrF2 as spectrographic carriers in the quantitative analysis of eighteen microcompound elements in uranium

International Nuclear Information System (INIS)

Gomes, R.P.; Lordello, A.R.; Abrao, A.

1977-01-01

A comparative study of the efficiency of some spectrochemical carriers (AgCl, In 2 O 3 , Ga 2 O 3 , NaF, LiF and SrF 2 ) is presented for the quantitative spectrographic analysis of Ag, Al, B, Bi, Cd, Cr, Cu, Fe, Mg, Mn, Mo, Ni, P, Pb, Si, Sn, V and Zn in uranium and its compounds. The volatility behaviour of the eighteen elements was verified by means of the moving plate technique for each of the mentioned carriers. The final aim was the selection of the carriers for the determination of trace amounts of the impurities. The best results were obtained with 4% In 2 O 3 , 6% AgCl and 6% NaF in a U 3 O 8 matrix. The sensitivities for some elements were extended to fractions of p.p.m. The precision, accuracy and acceptability of the method were calculated for all elements. The total error values are approximately in the range of 16-45% [pt

AgInCd control rod failure in the QUENCH-13 bundle test

International Nuclear Information System (INIS)

Sepold, L.; Lind, T.; Csordas, A. Pinter; Stegmaier, U.; Steinbrueck, M.; Stuckert, J.

2009-01-01

The QUENCH off-pile experiments performed at the Karlsruhe Research Center are to investigate the high-temperature behavior of Light Water Reactor (LWR) core materials under transient conditions and in particular the hydrogen source term resulting from the water injection into an uncovered LWR core. The typical LWR-type QUENCH test bundle, which is electrically heated, consists of 21 fuel rod simulators with a total length of approximately 2.5 m. The Zircaloy-4 rod claddings and the grid spacers are identical to those used in Pressurized Water Reactors (PWR) whereas the fuel is represented by ZrO 2 pellets. In the QUENCH-13 experiment the single unheated fuel rod simulator in the center of the test bundle was replaced by a PWR-type control rod. The QUENCH-13 experiment consisting of pre-oxidation, transient, and quench water injection at the bottom of the test section investigated the effect of an AgInCd/stainless steel/Zircaloy-4 control rod assembly on early-phase bundle degradation and on reflood behavior. Furthermore, in the frame of the EU 6th Framework Network of Excellence SARNET, release and transport of aerosols of a failed absorber rod were to be studied in QUENCH-13, which was accomplished with help of aerosol measurements performed by PSI-Switzerland and AEKI-Hungary. Control rod failure was initiated by eutectic interaction of steel cladding and Zircaloy-4 guide tube and was indicated at about 1415 K by axial peak absorber and bundle temperature responses and additionally by the on-line aerosol monitoring system. Significant releases of aerosols and melt relocation from the control rod were observed at an axial peak bundle temperature of 1650 K. At a maximum bundle temperature of 1820 K reflood from the bottom was initiated with cold water at a flooding rate of 52 g/s. There was no noticeable temperature escalation during quenching. This corresponds to the small amount of about 1 g in hydrogen production during the quench phase (compared to 42 g of H 2

AgNPs-3D nanostructure enhanced electrochemiluminescence of CdSe quantum dot coupled with strand displacement amplification for sensitive biosensing of DNA

International Nuclear Information System (INIS)

Jiao, Meng; Jie, Guifen; Tan, Lu; Niu, Shuyan

2017-01-01

A novel strategy using Ag nanoparticles-3D (AgNPs-3D) nanostructure enhanced electrochemiluminescence (ECL) of CdSe quantum dots (QDs) coupled with strand displacement amplification (SDA) for sensitive biosensing of DNA was successfully designed. The prepared CdSe QDs with intense ECL were assembled on the poly (diallyldimethylammonium chloride) (PDDA) graphene oxide (GO) nanocomposites modified electrode, then gold nanoparticles (NPs) as the quenching probe was conjugated to the QDs, ECL signal was efficiently quenched. The target DNA induced cycling SDA and generated a large number of DNA s1. The released DNA s1 could open the hairpin DNA with quenching probe. So the presence of low levels of target DNA can potentially result in a significant enhancement of ECL signal. Furthermore, large number of AgNPs were then in situ reduced in the 3D DNA skeleton on the electrode, which dramaticlly enhanced ECL signal of QDs owing to the excellent electrical conductivity, and the much amplified ECL signal change has a quantitative relation with the target DNA. So by combining the AgNPs-3D nanostructure and cycling SDA to achieve greatly amplified detection of DNA, the promising ECL strategy could provide a highly sensitive platform for various biomolecules and has a good prospect for clinical diagnosis in the future. - Graphical abstract: A novel strategy using AgNPs-3D nanostructure enhanced electrochemiluminescence of CdSe quantum dot coupled with DNA strand displacement amplification for sensitive biosensing of DNA was successfully designed, the proposed biosensor can be expected to be an emerging alternative for straightforward nucleic acid detection in complex samples with an easy and rapid way. - Highlights: • AgNPs-3D nanostructure for enhancing ECL signal of CdSe QDs was successfully designed. • A new dual amplification strategy for detection of DNA by using AgNPs-3D nanostructure coupled with SDA was developed. • It is for the first time AgNPs-3D nanostructure

Involvement of CD36 in Modulating the Decrease of NPY and AgRP Induced by Acute Palmitic Acid Stimulation in N1E-115 Cells

Directory of Open Access Journals (Sweden)

Yan Ma

2017-06-01

Full Text Available Central nervous system (CNS fatty acid sensing plays an important role in the regulation of food intake, and palmitic acid (PA is the most important long chain fatty acid (LCFA in the mammalian diet. To explore the effect of PA on central neuropeptide expression and the role of the cluster of the differentiation of 36 (CD36 in the process, N1E-115 cells were cultured with PA in the presence or absence of sulfosuccinimidyl-oleate (SSO, a CD36 inhibitor. Results showed that 10 μmol/L PA significantly reduced NPY and AgRP mRNA expression after 20 min of exposure, while the expression of CD36 was upregulated. The presence of SSO significantly attenuated the decrease of NPY and AgRP expression that was induced by PA alone, although no notable effect on PA- induced CD36 gene expression was observed. In conclusion, our study suggests the involvement of CD36 in the PA-induced decrease of NPY and AgRP in N1E-115 cells.

IL-5 promotes induction of antigen-specific CD4+CD25+ T regulatory cells that suppress autoimmunity.

Science.gov (United States)

Tran, Giang T; Hodgkinson, Suzanne J; Carter, Nicole M; Verma, Nirupama D; Plain, Karren M; Boyd, Rochelle; Robinson, Catherine M; Nomura, Masaru; Killingsworth, Murray; Hall, Bruce M

2012-05-10

Immune responses to foreign and self-Ags can be controlled by regulatory T cells (Tregs) expressing CD4 and IL-2Rα chain (CD25). Defects in Tregs lead to autoimmunity, whereas induction of Ag-specific CD4+CD25+ Tregs restores tolerance. Ag-specific CD4+CD25+ FOXP3+Tregs activated by the T helper type 2 (Th2) cytokine, IL-4, and specific alloantigen promote allograft tolerance. These Tregs expressed the specific IL-5Rα and in the presence of IL-5 proliferate to specific but not third-party Ag. These findings suggest that recombinant IL-5 (rIL-5) therapy may promote Ag-specific Tregs to mediate tolerance. This study showed normal CD4+CD25+ Tregs cultured with IL-4 and an autoantigen expressed Il-5rα. Treatment of experimental autoimmune neuritis with rIL-5 markedly reduced clinical paralysis, weight loss, demyelination, and infiltration of CD4+ (Th1 and Th17) CD8+ T cells and macrophages in nerves. Clinical improvement was associated with expansion of CD4+CD25+FOXP3+ Tregs that expressed Il-5rα and proliferated only to specific autoantigen that was enhanced by rIL-5. Depletion of CD25+ Tregs or blocking of IL-4 abolished the benefits of rIL-5. Thus, rIL-5 promoted Ag-specific Tregs, activated by autoantigen and IL-4, to control autoimmunity. These findings may explain how Th2 responses, especially to parasitic infestation, induce immune tolerance. rIL-5 therapy may be able to induce Ag-specific tolerance in autoimmunity.

Bioleaching mechanism of Zn, Pb, In, Ag, Cd and As from Pb/Zn smelting slag by autotrophic bacteria.

Science.gov (United States)

Wang, Jia; Huang, Qifei; Li, Ting; Xin, Baoping; Chen, Shi; Guo, Xingming; Liu, Changhao; Li, Yuping

2015-08-15

A few studies have focused on release of valuable/toxic metals from Pb/Zn smelting slag by heterotrophic bioleaching using expensive yeast extract as an energy source. The high leaching cost greatly limits the practical potential of the method. In this work, autotrophic bioleaching using cheap sulfur or/and pyrite as energy matter was firstly applied to tackle the smelting slag and the bioleaching mechanisms were explained. The results indicated autotrophic bioleaching can solubilize valuable/toxic metals from slag, yielding maximum extraction efficiencies of 90% for Zn, 86% for Cd and 71% for In, although the extraction efficiencies of Pb, As and Ag were poor. The bioleaching performance of Zn, Cd and Pb was independent of leaching system, and leaching mechanism was acid dissolution. A maximum efficiency of 25% for As was achieved by acid dissolution in sulfursulfur oxidizing bacteria (S-SOB), but the formation of FeAsO4 reduced extraction efficiency in mixed energy source - mixed culture (MS-MC). Combined works of acid dissolution and Fe(3+) oxidation in MS-MC was responsible for the highest extraction efficiency of 71% for In. Ag was present in the slag as refractory AgPb4(AsO4)3 and AgFe2S3, so extraction did not occur. Copyright © 2015 Elsevier Ltd. All rights reserved.

Root anatomy and element distribution vary between two Salix caprea isolates with different Cd accumulation capacities

International Nuclear Information System (INIS)

Vaculík, Marek; Konlechner, Cornelia; Langer, Ingrid; Adlassnig, Wolfram; Puschenreiter, Markus; Lux, Alexander; Hauser, Marie-Theres

2012-01-01

The understanding of the influence of toxic elements on root anatomy and element distribution is still limited. This study describes anatomical responses, metal accumulation and element distribution of rooted cuttings of Salix caprea after exposure to Cd and/or Zn. Differences in the development of apoplastic barriers and tissue organization in roots between two distinct S. caprea isolates with divergent Cd uptake and accumulation capacities in leaves might reflect an adaptive predisposition based on different natural origins. Energy-dispersive X-ray spectroscopy (EDX) revealed that Cd and Zn interfered with the distribution of elements in a tissue- and isolate-specific manner. Zinc, Ca, Mg, Na and Si were enriched in the peripheral bark, K and S in the phloem and Cd in both vascular tissues. Si levels were lower in the superior Cd translocator. Since the cuttings originated from stocks isolated from polluted and unpolluted sites we probably uncovered different strategies against toxic elements. - Highlights: ► We describe responses in roots of S. caprea exposed to Cd and Zn. ► Apoplastic barrier development varied among isolates from differently polluted sites. ► EDX analyses revealed variations of element distributions in root tissues. ► Si weight% was lower in the isolate with a higher Cd translocation capacity. ► S. caprea isolates possessed different strategies to respond to Cd and Zn. - S. caprea altered element distribution and translocation, apoplastic barrier development and root anatomy upon Cd and/or Zn exposure.

Transcriptome Analysis of Mycobacteria-Specific CD4+ T Cells Identified by Activation-Induced Expression of CD154.

Science.gov (United States)

Kunnath-Velayudhan, Shajo; Goldberg, Michael F; Saini, Neeraj K; Johndrow, Christopher T; Ng, Tony W; Johnson, Alison J; Xu, Jiayong; Chan, John; Jacobs, William R; Porcelli, Steven A

2017-10-01

Analysis of Ag-specific CD4 + T cells in mycobacterial infections at the transcriptome level is informative but technically challenging. Although several methods exist for identifying Ag-specific T cells, including intracellular cytokine staining, cell surface cytokine-capture assays, and staining with peptide:MHC class II multimers, all of these have significant technical constraints that limit their usefulness. Measurement of activation-induced expression of CD154 has been reported to detect live Ag-specific CD4 + T cells, but this approach remains underexplored and, to our knowledge, has not previously been applied in mycobacteria-infected animals. In this article, we show that CD154 expression identifies adoptively transferred or endogenous Ag-specific CD4 + T cells induced by Mycobacterium bovis bacillus Calmette-Guérin vaccination. We confirmed that Ag-specific cytokine production was positively correlated with CD154 expression by CD4 + T cells from bacillus Calmette-Guérin-vaccinated mice and show that high-quality microarrays can be performed from RNA isolated from CD154 + cells purified by cell sorting. Analysis of microarray data demonstrated that the transcriptome of CD4 + CD154 + cells was distinct from that of CD154 - cells and showed major enrichment of transcripts encoding multiple cytokines and pathways of cellular activation. One notable finding was the identification of a previously unrecognized subset of mycobacteria-specific CD4 + T cells that is characterized by the production of IL-3. Our results support the use of CD154 expression as a practical and reliable method to isolate live Ag-specific CD4 + T cells for transcriptomic analysis and potentially for a range of other studies in infected or previously immunized hosts. Copyright © 2017 by The American Association of Immunologists, Inc.

Specific accumulation of 20 trace elements in great cormorants (Phalacrocorax carbo) from Japan

International Nuclear Information System (INIS)

Nam, Dong-Ha; Anan, Yasumi; Ikemoto, Tokutaka; Okabe, Yuko; Kim, Eun-Young; Subramanian, Annamalai; Saeki, Kazutoshi; Tanabe, Shinsuke

2005-01-01

This study is to elucidate the specific accumulation of 20 trace elements in tissues/organs of great cormorants from two different colonies (Lake Biwa and Mie) in Japan. In the body distribution of trace elements, some elements revealed tissue-specific accumulation such as most of the burden of Mo, Ag and Cd in liver, Tl and Cd in kidney, Cu, Rb and Cs in muscle, and V, Sr and Ba in bone. Gender-related variation was not observed in both populations for most of the trace elements, except for higher hepatic Sr in males from Lake Biwa. Hepatic V, muscular Hg and Tl, and Cd in liver, kidney and muscle increased with growth. Comparison of trace element levels in tissues between the two colonies showed that Cr, Rb, Sr, Cd, Cs, Ba and Tl levels were higher in Lake Biwa than in Mie, whereas Zn, Co and Hg in Mie samples were greater than Lake Biwa. Variations of elemental levels in stomach contents also showed similar patterns, thus, showing that dietary sources tended to be the main factor for these regional variations. Toxic Hg and Cd concentrations in the liver of cormorants from the two colonies were lower than those from other areas, implying relatively low exposure to these metals in the present study sites. Concentrations of V, Co, Ag, Cd, Cs, Hg, Tl, Pb and Bi in liver remained more or less at the same level between 1993 and 2003, while hepatic Cr, Mn, Cu, Zn, Se, Rb, Sr and Ba showed apparent decrease, which might be related to the biological factors. - Dietary sources seemed to be the main reason for variable results

Comparison of trace element contamination levels (Cu, Zn, Fe, Cd ...

African Journals Online (AJOL)

SERVER

2008-03-18

Mar 18, 2008 ... Chemical analysis of the trace elements in the soft tissues. The trace elements of interest (Cu, Zn, Fe, Pb, Cd) were then determined in the digested solutions, using Thermoelemental type. M6 brand of an atomic absorption Spectrometer equipped with a flame operated atomisation system and a deuterium ...

Trace Element Concentration and Speciation in Selected Mining-Contaminated Soils and Water in Willow Creek Floodplain, Colorado

Directory of Open Access Journals (Sweden)

R. Burt

2011-01-01

Full Text Available Long-term mining activities in the mountains around Creede, Colorado have resulted in significant contamination in soils and water in the Willow Creek floodplain. Total major and trace were determined for soils and water and sequential chemical extraction for soils. Objectives were to determine concentrations and potential reactivity of trace elements and investigate their relationship with other soil and water properties. Water trace elements showed significant variability among sites, ranging from 347 to 12108 μg/L. Relative trend showed (Zn > Sr > Ba > (Mn > W > Cd > (Sn > V ≈ Ni ≈ Cu > Co > (Ag. Soil trace elements showed significant short-range spatial variability, ranging from 2819 to 19274 mg/kg. Relative trend showed (Pb ≈ Zn > Mn > Ba > P > (As > Cu > Sr > V > Cd > Sb ≈ Ag > (Co ≈ Cr > Mo ≈ Sn ≈ Ni > (Be ≈ W > Se ≈ Hg. Predominant fractions were oxide, specifically-sorbed/carbonate bound, and residual. Water soluble and exchangeable fractions showed (Zn ≈ Cd > Pb and Cd > Zn > Pb, respectively. Mobility factors for highly contaminated soils showed Cd ≈ Zn > Pb > Cu > As.

Phytoextraction of trace elements by water hyacinth in contaminated area of gold mine tailing.

Science.gov (United States)

Romanova, Tamara E; Shuvaeva, Olga V; Belchenko, Ludmila A

2016-01-01

The ability of water hyacinth (Eichhornia crassipes) to uptake Ag, Ba, Cd, Mo, and Pb from waters in gold mine tailing area was studied. All experiments were carried out in the field conditions without using of model system. Bioconcentration (BCF) and translocation factors (TF) as well as elements accumulation by plant in different points of tailings-impacted area were evaluated. It has been shown that water hyacinth demonstrates high ability to accumulate Mo, Pb, and Ba with BCF values 24,360 ± 3600, 18,800 ± 2800 and 10,040 ± 1400, respectively and is efficient in translocation of Mo and Cd. The general trend of the plant accumulation ability in relation to the studied elements corresponds to their concentration in the medium. As the distance from tailings increases, concentration of Ag, Ba and Pb in plant decreases more clearly than that of Cd, while the amount of Mo accumulated by plant doesn't drop significantly in accordance with its concentration in water. Under the conditions of the confluence of river Ur and drainage stream Ba and Ag can be considered as potential candidates for phytomining.

Structure analysis of complex metallic alloys in the Eu-Ag-In system by X-ray diffraction

International Nuclear Information System (INIS)

Gomez, Cesar Pay; Morita, Yoshiki; Tsai, An Pang; Yamamoto, Akiji

2009-01-01

In this work we investigate the complex atomic structures of two CMAs in the Eu-Ag-In system, these are quasicrystal approximants and their structures are similar to those of the 1/1 and 2/1 approximants found in the Yb-Cd system. The similarities between the Yb-Cd and Eu-Ag-In systems indicate that the RE-Ag-In systems in several ways can be treated as pseudo-binary. The investigated phases however also show some interesting differences; when Cd is replaced by the elements Ag and In partial chemical disorder is introduced into the system. As a response, the positional disorder which is usually observed in certain atomic positions for these types of approximants tends to disappear. The complete structures refined from single crystal data are described in detail and the differences with other related phases are highlighted. The 2/1 approximant in the Eu-Ag-In system is the first to exhibit such a degree of structural perfection in terms of positional order, a feature which makes this phase very suitable for further studies of chemical order and also can give insight into the local structures of related disordered phases. Electron diffraction studies on the 1/1 approximant phase have previously shown the presence of weak superlattice reflections, indicating a superstructure similar to that of the related phase Eu 4 Cd 25 . However, no superlattice reflections could be observed by single crystal diffraction and it is thus concluded that the phase has a disordered average structure with possible short to medium range superlattice ordering.

Breaking tolerance in hepatitis B surface antigen (HBsAg) transgenic mice by vaccination with cross-reactive, natural HBsAg variants

DEFF Research Database (Denmark)

Schirmbeck, Reinhold; Dikopoulos, Nektarios; Kwissa, Marcin

2003-01-01

Processing exogenous hepatitis B surface antigen (HBsAg) of the hepatitis B virus (HBV) generates the K(b)-binding S(208-215) epitope 1; processing endogenous HBsAg generates the K(b)-binding S(190-197) epitope 2. Cross-reactive CD8(+) T cell responses were primed to epitope 1 but not epitope 2...... HBs-tg mice showed reduced antigenemia. Hence, vaccination with natural HBsAg variants from different HBV sero/genotypes can prime cross-reactive, specific CD8(+) T cell immunity that breaks tolerance to HBsAg....

The impact of electrostatic interactions on ultrafast charge transfer at Ag 29 nanoclusters–fullerene and CdTe quantum dots–fullerene interfaces

KAUST Repository

Ahmed, Ghada H.; Parida, Manas R.; Tosato, Alberto; AbdulHalim, Lina G.; Usman, Anwar; Alsulami, Qana; Banavoth, Murali; Alarousu, Erkki; Bakr, Osman; Mohammed, Omar F.

2015-01-01

investigate the electrostatic interactions between the positively charged fullerene derivative C60-(N,N dimethylpyrrolidinium iodide) (CF) employed as an efficient molecular acceptor and two different donor molecules: Ag29 nanoclusters (NCs) and CdTe quantum

Trace elements in primitive meteorites—VII Antarctic unequilibrated ordinary chondrites

Science.gov (United States)

Wang, Ming-Sheng; Lipschutz, Michael E.

2007-02-01

We report RNAA results for Co, Au, Sb, Ga, Rb, Cs, Se, Ag, Te, Zn, In, Bi, Tl and Cd (in increasing order of metamorphic mobility) in 22 Antarctic unequilibrated ordinary chondrites (UOC). This brings to 38 the number of UOC for which data for highly volatile elements are known. For elements of lesser mobility (Co to Se, omitting Cs) overall variability in UOC are low, relative standard deviations (one sigma) being no more than a factor of two. For Ag, Te and Zn, relative standard deviations are 2-4×, while for Cs and the four most volatile elements, the variabilities are 8-110×. Elemental abundances do not vary with chemical type (H, L and LL) nor with UOC subtype (3.0-3.9). Contents of all elements reach levels up to, even exceeding, cosmic and all but Cd and the two alkalis, seem unaffected by post-accretionary processes. Contents of highly volatile elements are consistent with the idea that source regions producing contemporary falls and older Antarctic UOC differed in thermal histories. The presence or absence of carbide magnetite assemblages (CMA) generally accords with high or low Cd contents, respectively. This relationship accords with the prior suggestion that CMA formed by alteration of Fe-Ni metal by C-O-H-containing fluids at temperatures indicate that they were subsequently destroyed as metamorphic intensity increased. The high, often supercosmic, Rb and Cs levels in UOC may result from their high solubility in liquid water signalling their redistribution by C-O-H-containing fluid while in the liquid water field. Because of its uniquely high mobility, Cd could have been enriched by the C-O-H fluids and should have been lost from parent regions during later, higher temperature anhydrous metamorphism at temperatures in the 500-600 °C range.

Ag85A-specific CD4+ T cell lines derived after boosting BCG-vaccinated cattle with Ad5-85A possess both mycobacterial growth inhibition and anti-inflammatory properties.

Science.gov (United States)

Metcalfe, Hannah J; Biffar, Lucia; Steinbach, Sabine; Guzman, Efrain; Connelley, Tim; Morrison, Ivan; Vordermeier, H Martin; Villarreal-Ramos, Bernardo

2018-05-11

There is a need to improve the efficacy of the BCG vaccine against human and bovine tuberculosis. Previous data showed that boosting bacilli Calmette-Guerin (BCG)-vaccinated cattle with a recombinant attenuated human type 5 adenovirally vectored subunit vaccine (Ad5-85A) increased BCG protection and was associated with increased frequency of Ag85A-specific CD4 + T cells post-boosting. Here, the capacity of Ag85A-specific CD4 + T cell lines - derived before and after viral boosting - to interact with BCG-infected macrophages was evaluated. No difference before and after boosting was found in the capacity of these Ag85A-specific CD4 + T cell lines to restrict mycobacterial growth, but the secretion of IL-10 in vitro post-boost increased significantly. Furthermore, cell lines derived post-boost had no statistically significant difference in the secretion of pro-inflammatory cytokines (IL-1β, IL-12, IFNγ or TNFα) compared to pre-boost lines. In conclusion, the protection associated with the increased number of Ag85A-specific CD4 + T cells restricting mycobacterial growth may be associated with anti-inflammatory properties to limit immune-pathology. Copyright © 2018 Department for Environment Food and Rural Affairs. Published by Elsevier Ltd.. All rights reserved.

CD27 instructs CD4+ T cells to provide help for the memory CD8+ T cell response after protein immunization

NARCIS (Netherlands)

Xiao, Yanling; Peperzak, Victor; Keller, Anna M.; Borst, Jannie

2008-01-01

For optimal quality, memory CD8(+) T cells require CD4(+) T cell help. We have examined whether CD4(+) T cells require CD27 to deliver this help, in a model of intranasal OVA protein immunization. CD27 deficiency reduced the capacity of CD4(+) T cells to support Ag-specific CD8(+) T cell

A 90 element CdTe array detector

Energy Technology Data Exchange (ETDEWEB)

Iwase, Y.; Onozuka, A.; Ohmori, M. (Nippon Mining Co. Ltd., Toda, Saitama (Japan). Electronic Material and Components Labs.); Funaki, M. (Nippon Mining Co. Ltd., Toda, Saitama (Japan). Materials Development Research Labs.)

1992-11-15

The fabrication of a CdTe array radiation detector and its radiation detection characteristics are described. In order to obtain high efficiency of charge collection and realize uniform detection sensitivity, current-voltage characteristics with the combination of large and small barrier height contacts and three kinds of CdTe crystals have been investigated. It was found that the Schottky barrier height of electroless Pt deposition was 0.97 eV, which effectively suppressed electron injection. By using the crystal grown by the travelling heater method with a Cl concentration of 2 ppm, carrier lifetimes for electrons and holes of 1.0 and 0.5 [mu]s, respectively, were achieved. A 90 element array detector exhibited an energy resolution as low as 4.5 keV and a count rate variation of less than 5% for 60 keV [gamma]-rays. (orig.).

A 90 element CdTe array detector

Science.gov (United States)

Iwase, Y.; Funaki, M.; Onozuka, A.; Ohmori, M.

1992-11-01

The fabrication of a CdTe array radiation detector and its radiation detection characteristics are described. In order to obtain high efficiency of charge collection and realize uniform detection sensitivity, current-voltage characteristics with the combination of large and small barrier height contacts and three kinds of CdTe crystals have been investigated. It was found that the Schottky barrier height of electroless Pt deposition was 0.97 eV, which effectively suppressed electron injection. By using the crystal grown by the travelling heater method with a Cl concentration of 2 ppm, carrier lifetimes for electrons and holes of 1.0 and 0.5 μs, respectively, were achieved. A 90 element array detector exhibited an energy resolution as low as 4.5 keV and a count rate variation of less than 5% for 60 keV γ-rays.

Studying the Range of Incident Alpha Particles on Cu , Ge , Ag , Cd , Te and Au, With Energy (4-15 MeV)

International Nuclear Information System (INIS)

Kadhim, R.O.; Jasim, W.N.

2015-01-01

In this paper theoretical calculation of the range for alpha particles with the energy range (4 – 15)MeV when passing in some metallic media (Cu , Ge , Ag , Cd , Te and Au).Semi empirical formula was used in addition to (SRIM-2012) program. The Semi empirical equation was programmed to calculate the range using Matlab Language.The results of the range in these media were compared with the results obtained from SRIM-2012 and )(2011)Andnet) results.There was good agreement among the semi empirical equation result , SRIM- 2012 results and with )(2011)Andnet) results in the low energy.The results showed exponential relation between the range of alpha particles in these media and the velocity of the particles.By recourse with SRIM- 2012 results and application them in Matlab program and by using Curve Fitting Tool we extraction equation with its constants to calculate the range of alpha particles in any element of these six elements with the energy range (4 – 15)MeV.The maximum deviation between the results from the semi empirical calculation and SRIM-2012 results was calculated the statistical test ( kstest2) in Matlab program

Investigation of electroluminescence properties of CdTe@CdS core ...

Indian Academy of Sciences (India)

CdTe@CdS(core-shell)/Mg:Ag struc- ture. .... This phenomenon can be caused by the increase in size of particles due to the growth of CdS shell. The red shift upon shell growth is the result of decrease in the kinetic energy of the excited elec-.

Multivariate characterization of elements accumulated in King Bolete Boletus edulis mushroom at lowland and high mountain regions.

Science.gov (United States)

Falandysz, J; Kunito, T; Kubota, R; Bielawski, L; Frankowska, A; Falandysz, Justyna J; Tanabe, S

2008-12-01

Based on ICP-MS, ICP-OES, HG-AAS, CV-AAS and elementary instrumental analysis of King Bolete collected from four sites of different soil bedrock geochemistry considered could be as mushroom abundant in certain elements. King's Bolete fruiting bodies are very rich in K (> 20 mg/g dry weight), rich in Ca, Mg, Na, Rb and Zn (> 100 microg/g dw), and relatively also rich in Ag, Cd, Cs, Cu, Fe, Mn and Se (> 10 microg/g dw). The caps of King Bolete when compared to stipes around two-to three-fold more abundant are in Ag, Cd, Cs, Cu, Hg, K, Mg, Mo, N, Rb, Se and Zn. King Bolete collected at the lowland and mountain sites showed Ag, Ba, Co, Cr, Hg, K, Mg, Mn, Mo and Na in caps in comparable concentrations, and specimens from the mountain areas accumulated more Cd and Sb. Elements such as Al, Pb and Rb occurred at relatively elevated concentration in King Bolete picked up at the metal ores-rich region of the Sudety Mountains. Because of high bioconcentration potential King Bolete at the background sites accumulate in fruiting bodies great concentrations of problematic elements such as Cd, Pb and Hg, i.e. up to nearly 20, 3 and 5 microg/g dw, on the average, respectively. The interdependence among determined mineral elements examined were using the principal components analysis (PCA) method. The PCA explained 56% of the total variance. The metals tend to cluster together (Ba, Cd, Cs, Cr, Ga, Rb, Se, Sr and V; K and Mg; Cu and Mo). The results provided useful environmental and nutritional background level information on 26 minerals as the composition of King Bolete from the sites of different bedrock soil geochemistry.

Progress in Solving the Elusive Ag Transport Mechanism in TRISO Coated Particles: “What is new?”

International Nuclear Information System (INIS)

Rooyen, I.J. van; Petti, D.A.; Nabielek, H.; Neethling, J.H; Kania, M.J.

2014-01-01

The tristructural isotropic (TRISO) particle for a high temperature reactor (HTR) has been developed to an advanced state where the coating withstands internal gas pressures and retains nearly all fission products during irradiation and under postulated accidents. However, one exception is silver (Ag) that has been found to be released from high quality TRISO coated particles during irradiation and high temperature accident heating tests. Although out-of-pile laboratory tests have yet to elucidate the mechanism of transport of Ag through silicon carbide (SiC), effective diffusion coefficients have been derived to successfully reproduce measured "1"1"0"mAg- releases from irradiated HTR fuel elements, compacts and TRISO particles. It was found that Ag transport through SiC does not proceed via bulk volume diffusion. Presently grain boundary diffusion that may be irradiation enhanced either by neutron bombardment or by the presence of fission products such as palladium (Pd), are the two hypotheses that have been proposed. Recent studies of irradiated AGR-1 TRISO fuel using scanning transmission electron microscopy (STEM), transmission Kikuchi diffraction (TKD) patterns, and high resolution transmission electron microscopy (HRTEM) have been used to further the understanding of Ag transport through TRISO particles. No Ag was observed in SiC grains, but Ag was identified at triple-points and grain boundaries of the SiC layer in the TRISO particle. Cadmium (Cd) was also found in some of the very same triple junctions, but this could be related to silver behavior as "1"1"0"mAg decays to "1"1"0Cd or true Cd release as a fission product. Palladium was identified as the main constituent of micron-sized precipitates present at the SiC grain boundaries. The potential role of Pd in the transport of Ag will be discussed further. (author)

Simultaneous regulation of CD2 adhesion and signaling functions by a novel CD2 monoclonal antibody

NARCIS (Netherlands)

van Kemenade, F. J.; Tellegen, E.; Maurice, M. M.; Lankester, A. C.; Kuijpers, T. W.; Brouwer, M.; de Jong, R.; Miedema, F.; van Lier, R. A.

1994-01-01

Accessory molecules on T cells can support adhesion and transduce agonistic signals that facilitate Ag receptor-induced T cell activation. The T cell differentiation Ag CD2 may exert both functions, as has been amply demonstrated in studies with CD2 mAbs. In addition, experiments in which either

Stimulation of the photoluminescent properties of CBD-CdS thin films achieved by structural modifications resulting from Ag{sup +} doping

Energy Technology Data Exchange (ETDEWEB)

Flores-Pacheco, A.; Contreras-Rascon, J.I.; Castillo, S.J.; Alvarez-Ramos, M.E. [Posgrado en Nanotecnologia, Departamento de Fisica, Universidad de Sonora, Hermosillo (Mexico); Diaz-Reyes, J. [Centro de Investigacion en Biotecnologia Aplicada, Instituto Politecnico Nacional, Tepetitla, Tlaxcala (Mexico); Angel-Vicente, P.D. [Instituto Mexicano del Petroleo, Direccion de Investigacion y Posgrado, Ciudad de Mexico (Mexico); Enriquez, J.P. [Centro de Investigacion y Desarrollo Tecnologico en Energias Renovables, Universidad de Ciencias y Artes de Chiapas, Tuxtla Gutierrez (Mexico)

2017-08-15

The present study details the changes in photoluminescence properties stimulated by the structural changes in consequence of doping the II-VI nanocomposite thin-film semiconductor cadmium sulfide (CdS) with the IB metallic ion Ag{sup +}. The synthesis of the matrix and doped semiconductors was performed using low-temperature chemical bath deposition (CBD). The doping percentage of the CdS matrix was determined by energy-dispersive X-ray spectroscopy (EDS) with a value around 3%. The crystallographic study shows a cubic (1 1 1) preferential growth plane for the undoped material. Both X-ray and HRTEM characterizations show the presence of a polycrystalline structure for the Ag{sup +}-doped sample. Measurements of particle size from HRTEM micrographs confirm quantum confinement with a reduction of the average particle size from 5.46 to 4.12 nm in the doped sample. The photoluminescence study shows intense downshifted emissions in the green range of the visible spectrum. This could be due to the shallow electron traps formed by crystalline defects in the lattice, which are induced by the metallic ion. This study also shows higher-energy emissions due to the decrease of the particle size below the effective CdS exciton Bohr radius. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Effect of silver doping on the elastic properties of CdS nanoparticles

Science.gov (United States)

Dey, P. C.; Das, R.

2018-05-01

CdS and Ag doped CdS (CdS/Ag) nanoparticles have been prepared via chemical method from a Cadmium acetate precursor and Thiourea. The synthesized CdS and CdS/Ag nanoparticles have been characterized by the X-ray Diffraction and High Resolution Transmission Electron Microscope. Here, these nanoparticles have been synthesized at room temperature and all the characterization have also been done at room temperature only. The XRD results reveal that the products are crystalline with cubic zinc blende structure. HRTEM images show that the prepared nanoparticles are nearly spherical in shape. Williamson-Hall method and Size-Strain Plot (SSP) have been used to study the individual contribution of crystalline sizes and lattice strain on the peak broadening of the CdS and CdS/Ag nanoparticles. The different modified model of Williamson-Hall method such as, uniform deformation model, uniform stress deformation model and uniform energy density deformation model and SSP method have been used to calculate the different physical parameter such as lattice strain, stress and energy density for all diffraction peaks of the XRD, corresponding to the CdS and silver doped CdS (CdS/Ag). The obtained results reveal that the average particle size of the prepared CdS and CdS/Ag nanoparticles estimated from the HRTEM images, Williamson-Hall analysis and SSP method are highly correlated with each other. Further, all these result confirms that doping of Ag significantly affects the elastic properties of CdS.

The oscillations in ESR spectra of Hg0.76Cd0.24Te implanted by Ag+ at the X and Q-bands

Science.gov (United States)

Shestakov, A. V.; Fazlizhanov, I. I.; Yatsyk, I. V.; Gilmutdinov, I. F.; Ibragimova, M. I.; Shustov, V. A.; Eremina, R. M.

2018-05-01

The objects of the investigation were uniformly Ag+ doped Hg0.76Cd0.24Te mercury chalcogenide monocrystals obtained by ion implantation with subsequent thermal annealing over 20 days. After implantation and annealing the conductivity was inverted from n-type with carrier concentration of 1016 cm‑3 to p-type with carrier concentration of ≈ 3.9 × 1015 cm‑3. The investigations of microwave absorption derivative (dP/dH) showed the existence of strong oscillations in the magnetic field for Ag:Hg0.76Cd0.24Te in the temperature range 4.2–12 K. The concentration and effective mass of charge carrier were determined from oscillation period and temperature dependency of oscillation amplitude. We suppose that this phenomenon is similar to the de Haas–van Alphen effect in weakly correlated electron system with imperfect nesting vector.

Essential and toxic element concentrations in monofloral honeys from southern Croatia.

Science.gov (United States)

Bilandžić, Nina; Tlak Gajger, Ivana; Kosanović, Marina; Čalopek, Bruno; Sedak, Marija; Solomun Kolanović, Božica; Varenina, Ivana; Luburić, Đurđica Božić; Varga, Ines; Đokić, Maja

2017-11-01

The concentrations of 24 elements in seven honey types (multifloral, heather, common heather, bearberry, sage, mandarin orange-blossom and honeydew) collected in southern Mediterranean regions of Croatia were determined using ICP-MS. Significant differences were found in the concentrations of Ag, As, Ba, Cu, Co, Fe, K, Mg, Mn, Mo, Na, Ni, Se, Sb, U and Th (p<0.05, all) among honeys. The highest element concentrations were determined in honeydew honeys, with the exception of multifloral (Ca, Cr, Mo, Se), common heather (Mg, Na), bearberry (Ba, Fe, Pb) and sage (Ag) honeys. Among the floral honeys, the highest concentrations were found in multifloral honey (Al, As, Be, Ca, Cr, Mn, Mo, Ni, Se, Th and U), common heather (Co, K, Mg, Na, V), sage (Ag, Cd, Cu), and bearberry (Ba, Fe, Pb, Sb, Zn). The results contribute to the evidence supporting the role of botanical origin on the elemental composition of honey. Copyright © 2017 Elsevier Ltd. All rights reserved.

Determination of integral K-shell Compton scattering cross-sections in elements 41>=Z>=51 for 1250 keV photons

Energy Technology Data Exchange (ETDEWEB)

Verma, S L; Allawadhi, K L; Sood, B S [Punjabi Univ., Patiala (India). Dept. of Physics

1978-04-01

Integral K-shell Compton scattering cross-sections in elements Nb, Mo, Ag, Cd, In, Sn and Sb have been determined for 1250 keV photons. The results when compared with theory suggest that K-shell electrons in the elements under investigation behave as free electrons.

Insight on trace element detoxification in the Black-tailed Godwit (Limosa limosa) through genetic, enzymatic and metallothionein analyses

Energy Technology Data Exchange (ETDEWEB)

Lucia, Magali, E-mail: m.lucia33@laposte.net [Littoral, Environnement et Societes (LIENSs), UMR 7266 CNRS-Universite de La Rochelle, 2 rue Olympe de Gouges, 17000 La Rochelle (France); Bocher, Pierrick [Littoral, Environnement et Societes (LIENSs), UMR 7266 CNRS-Universite de La Rochelle, 2 rue Olympe de Gouges, 17000 La Rochelle (France); Cosson, Richard P. [Mer Molecules Sante (MMS), Universite de Nantes, EA 2663, 2 rue de la Houssiniere, BP 92208, 44322 Nantes Cedex 3 (France); Churlaud, Carine; Robin, Frederic; Bustamante, Paco [Littoral, Environnement et Societes (LIENSs), UMR 7266 CNRS-Universite de La Rochelle, 2 rue Olympe de Gouges, 17000 La Rochelle (France)

2012-04-15

Trace element concentrations (Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Zn) were investigated in the liver, kidneys, muscle and feathers of 31 black-tailed godwits (Limosa limosa) accidentally killed during catches by mist net in the Pertuis Charentais, Atlantic coast of France. Analyses of carbon and nitrogen stable isotope ratios were carried out in liver, muscle and feathers in order to elucidate dietary patterns and to determine whether differences in diet explained the variation in elemental uptake. This study also aimed to have a preliminary assessment of sub-lethal effects triggered by trace elements through the investigation of gene expressions by quantitative real-time PCR, antioxidant enzyme activities (catalase, superoxide dismutase, glutathione peroxidase), and metallothionein (MT) levels. The results showed that Cr and Ni concentrations in tissues of adults were lower than in juveniles in part because adults may have eliminated these trace elements through moulting. Except for Cd and Ni, trace element concentrations were negatively correlated to the body mass of godwits. Ag, As, Hg and Se concentrations were positively linked with the trophic position of birds. The diet could be considered as a fundamental route of exposure for these elements demonstrating therefore the qualitative linkage between dietary habits of godwits and their contaminant concentrations. Our results strongly suggest that even though trace element concentrations were mostly below toxicity threshold level, the elevated concentrations of As, Ag, Cd, Cu, Fe and Se may however trigger sub-lethal effects. Trace elements appear to enhance expression of genes involved in oxidative stress defence, which indicates the production of reactive oxygen species. Moreover, birds with the highest concentrations appeared to have an increased mitochondrial metabolism suggesting that the fight against trace element toxicity requires additional energetic needs notably to produce detoxification

Insight on trace element detoxification in the Black-tailed Godwit (Limosa limosa) through genetic, enzymatic and metallothionein analyses

International Nuclear Information System (INIS)

Lucia, Magali; Bocher, Pierrick; Cosson, Richard P.; Churlaud, Carine; Robin, Frédéric; Bustamante, Paco

2012-01-01

Trace element concentrations (Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Zn) were investigated in the liver, kidneys, muscle and feathers of 31 black-tailed godwits (Limosa limosa) accidentally killed during catches by mist net in the Pertuis Charentais, Atlantic coast of France. Analyses of carbon and nitrogen stable isotope ratios were carried out in liver, muscle and feathers in order to elucidate dietary patterns and to determine whether differences in diet explained the variation in elemental uptake. This study also aimed to have a preliminary assessment of sub-lethal effects triggered by trace elements through the investigation of gene expressions by quantitative real-time PCR, antioxidant enzyme activities (catalase, superoxide dismutase, glutathione peroxidase), and metallothionein (MT) levels. The results showed that Cr and Ni concentrations in tissues of adults were lower than in juveniles in part because adults may have eliminated these trace elements through moulting. Except for Cd and Ni, trace element concentrations were negatively correlated to the body mass of godwits. Ag, As, Hg and Se concentrations were positively linked with the trophic position of birds. The diet could be considered as a fundamental route of exposure for these elements demonstrating therefore the qualitative linkage between dietary habits of godwits and their contaminant concentrations. Our results strongly suggest that even though trace element concentrations were mostly below toxicity threshold level, the elevated concentrations of As, Ag, Cd, Cu, Fe and Se may however trigger sub-lethal effects. Trace elements appear to enhance expression of genes involved in oxidative stress defence, which indicates the production of reactive oxygen species. Moreover, birds with the highest concentrations appeared to have an increased mitochondrial metabolism suggesting that the fight against trace element toxicity requires additional energetic needs notably to produce detoxification

Trace Elements in Teeth by ICPMS

International Nuclear Information System (INIS)

Zahran, N.F.; Helal, A.I.; Amr, M.A.; Amr, M.A.; Al-saad, K.A.

2008-01-01

Teeth are reported to be suitable indicators of trace element exposure from environment and nutritional status. Inductively coupled plasma mass spectrometry (ICP-MS) is used to compare the trace element content of children's primary teeth and adult teeth. Primary teeth are collected from 28 children and 42 adult from non-industrial City. The data are assessed statistically using t-tests. The adult teeth contained significantly greater concentrations of Na, Mg, Al, Fe, Ni, Cu, Sr, Cd, Ba, Pb and U and significantly less Mn, Co, As, Se, Mo and Bi than the children teeth. Additional measurements on adult teeth pulps are performed. Comparison between trace element concentrations in health and caries teeth pulps show that the mean concentrations of Na, Al, K, Cr, Mn, Co, Cu, Zn, Mo, Ag, Bi and U are lower in caries than healthy teeth pulps. On the other hand, the mean concentrations of Mg, Cd and Pb are higher in caries samples than healthy teeth pulps

Comparison of trace element contamination levels (Cu, Zn, Fe, Cd ...

African Journals Online (AJOL)

Comparison of trace element contamination levels (Cu, Zn, Fe, Cd and Pb) in the soft tissues of the gastropods Tympanotonus fuscatus fuscatus and Tf radula collected in the Ebrié Lagoon (Côte d'Ivoire): Evidence of the risks linked to linked to lead and.

Metal ion displacements in noncentrosymmetric chalcogenides La{sub 3}Ga{sub 1.67}S{sub 7}, La{sub 3}Ag{sub 0.6}GaCh{sub 7} (Ch=S, Se), and La{sub 3}MGaSe{sub 7} (M=Zn, Cd)

Energy Technology Data Exchange (ETDEWEB)

Iyer, Abishek K. [Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G2G2 (Canada); Yin, Wenlong [Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G2G2 (Canada); Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang 621900 (China); Rudyk, Brent W. [Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G2G2 (Canada); Lin, Xinsong [Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G2G2 (Canada); Centre for Oil Sands Sustainability, Northern Alberta Institute of Technology, Edmonton, Alberta, Canada T6N1E5 (Canada); Nilges, Tom [Department of Chemistry, Technical University of Munich, 85748 Garching b. München (Germany); Mar, Arthur, E-mail: arthur.mar@ualberta.ca [Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G2G2 (Canada)

2016-11-15

The quaternary Ga-containing chalcogenides La{sub 3}Ag{sub 0.6}GaS{sub 7}, La{sub 3}Ag{sub 0.6}GaSe{sub 7}, La{sub 3}ZnGaSe{sub 7}, and La{sub 3}CdGaSe{sub 7}, as well as the related ternary chalcogenide La{sub 3}Ga{sub 1.67}S{sub 7}, were prepared by reactions of the elements at 950 °C. They adopt noncentrosymmetric hexagonal structures (space group P6{sub 3}, Z=2) with cell parameters (a=10.2 Å, c=6.1 Å for the sulfides; a=10.6 Å, c=6.4 Å for the selenides) that are largely controlled by the geometrical requirements of one-dimensional stacks of Ga-centered tetrahedra separated by the La atoms. Among these compounds, which share the common formulation La{sub 3}M{sub 1–x}GaCh{sub 7} (M=Ga, Ag, Zn, Cd; Ch=S, Se), the M atoms occupy sites within a stacking of trigonal antiprisms formed by Ch atoms. The location of the M site varies between extremes with trigonal antiprismatic (CN6) and trigonal planar (CN3) geometry. Partial occupation of these sites and intermediate ones accounts for the considerable versatility of these structures and the occurrence of large metal displacement parameters. The site occupations can be understood in a simple way as being driven by the need to satisfy appropriate bond valence sums for both the M and Ch atoms. Band structure calculations rationalize the substoichiometry observed in the Ag-containing compounds (La{sub 3}Ag{sub 0.6}GaS{sub 7}, La{sub 3}Ag{sub 0.6}GaSe{sub 7}) as a response to overbonding. X-ray photoelectron spectroscopy supports the presence of monovalent Ag atoms in these compounds, which are not charge-balanced. - Graphical abstract: Partial occupation of metal atoms in multiple sites accounts for versatility in Ga-containing chalcogenides La{sub 3}M{sub 1–x}GaCh{sub 7} with noncentrosymmetric hexagonal structures. - Highlights: • La{sub 3}M{sub 1–x}GaCh{sub 7} (M =Ga, Ag, Zn, Cd; Ch =S, Se) adopt related hexagonal structures. • Large displacements of M atoms originate from partial occupation of multiple

Macro and Trace Element Accumulation in Edible Crabs and Frogs ...

African Journals Online (AJOL)

The tissue accumulation of five macroelements (Na, Mg, K, Ca, Fe) and twelve trace elements (Vd, Mn, Co, Ni, Cu, Zn, As, Se, Mo, Ag, Cd, Pb) were assessed in the organs of the edible frogs; Xenopus laevis and Rana esculentus, and whole body of the crab, Callinestes caught from Alaro Stream Floodplain (Ibadan, ...

Retrogenic ICOS Expression Increases Differentiation of KLRG-1hiCD127loCD8+ T Cells during Listeria Infection and Diminishes Recall Responses.

Science.gov (United States)

Liu, Danya; Burd, Eileen M; Coopersmith, Craig M; Ford, Mandy L

2016-02-01

Following T cell encounter with Ag, multiple signals are integrated to collectively induce distinct differentiation programs within Ag-specific CD8(+) T cell populations. Several factors contribute to these cell fate decisions, including the amount and duration of Ag, exposure to inflammatory cytokines, and degree of ligation of cosignaling molecules. The ICOS is not expressed on resting T cells but is rapidly upregulated upon encounter with Ag. However, the impact of ICOS signaling on programmed differentiation is not well understood. In this study, we therefore sought to determine the role of ICOS signaling on CD8(+) T cell programmed differentiation. Through the creation of novel ICOS retrogenic Ag-specific TCR-transgenic CD8(+) T cells, we interrogated the phenotype, functionality, and recall potential of CD8(+) T cells that receive early and sustained ICOS signaling during Ag exposure. Our results reveal that these ICOS signals critically impacted cell fate decisions of Ag-specific CD8(+) T cells, resulting in increased frequencies of KLRG-1(hi)CD127(lo) cells, altered BLIMP-1, T-bet, and eomesodermin expression, and increased cytolytic capacity as compared with empty vector controls. Interestingly, however, ICOS retrogenic CD8(+) T cells also preferentially homed to nonlymphoid organs and exhibited reduced multicytokine functionality and reduced ability to mount secondary recall responses upon challenge in vivo. In sum, our results suggest that an altered differentiation program is induced following early and sustained ICOS expression, resulting in the generation of more cytolyticly potent, terminally differentiated effectors that possess limited capacity for recall response. Copyright © 2016 by The American Association of Immunologists, Inc.

Facile, one-pot and scalable synthesis of highly emissive aqueous-based Ag,Ni:ZnCdS/ZnS core/shell quantum dots with high chemical and optical stability

Science.gov (United States)

Sahraei, Reza; Soheyli, Ehsan; Faraji, Zahra; Soleiman-Beigi, Mohammad

2017-11-01

We report here on a one-pot, mild and low cost aqueous-based synthetic route for the preparation of colloidally stable and highly luminescent dual-doped Ag,Ni:ZnCdS/ZnS core/shell quantum dots (QDs). The pure dopant emission of the Ni-doped core/shell QDs was found to be highly affected by the presence of a second dopant ion (Ag+). Results showed that the PL emission intensity increases while its peak position experiences an obvious blue shift with an increase in the content of Ag+ ions. Regarding the optical observations, we provide a simple scheme for absorption-recombination processes of the carriers through impurity centers. To obtain optimum conditions with a better emission characteristic, we also study the effect of different reaction parameters, such as refluxing temperature, the pH of the core and shell solution, molar ratio of the dopant ions (Ni:(Zn+Cd) and Ag:(Zn+Cd)), and concentration of the core and shell precursors. Nonetheless, the most effective parameter is the presence of the ZnS shell in a suitable amount to eliminate surface trap states and enhance their emission intensity. It can also improve the bio-compatibility of the prepared QDs by restricting the Cd2+ toxic ions inside the core of the QDs. The present suggested route also revealed the remarkable optical and chemical stability of the colloidal QDs which establishes them as a decent kind of nano-scale structure for light emitting applications, especially in biological technologies. The suggested process also has the potential to be scaled-up while maintaining the emission characteristics and structural quality necessary for industrial applications in optoelectronic devices.

Bio- and toxic elements in mushrooms from the city of Umeå and outskirts, Sweden.

Science.gov (United States)

Mędyk, Małgorzata; Grembecka, Małgorzata; Brzezicha-Cirocka, Justyna; Falandysz, Jerzy

2017-08-03

Edible mushrooms (Albatrellus ovinus, Boletus edulis, Clitocybe odora, Gomphidius glutinosus, Leccinum scabrum, Leccinum versipelle, Lycoperdon perlatum, Suillus bovinus, Suillus luteus, and Xerocomus subtomentosus) collected from unpolluted areas of the city of Umeå and its outskirts in the northern part of Sweden were examined for contents of toxic metallic elements (Cd, Pb, and Ag) and essential macro- and microelements (K, Na, Ca, Mg, Cu, Fe, Mn, and Zn) using a validated method and a final measurement by flame atomic absorption spectroscopy (F-AAS). The median values of the toxic metallic element concentrations (in mg kg -1 dry biomass, db) ranged from: 0.12-3.9, 0.46-5.1, and 0.91-6.2 for Ag, Cd and Pb, respectively. For the essential metallic elements, the median values of concentrations ranged from: 24000-58000, 15-2000, 59-610, 520-1900, 2.0-97, 16-150, 15-120, and 4.3-26 mg kg -1 db for K, Na, Ca, Mg, Cu, Zn, Fe, and Mn, respectively. The baseline concentrations of the metallic elements determined in mushrooms were mainly affected by the fungal species. The assessed probable maximal dietary intake of Cd (0.002 mg kg -1 body mass) solely from a mushroom meal was only slightly below a revised value of the tolerable weekly intake for this element, while for Pb (0.003 mg kg -1 body mass) it was tenfold below the provisionally tolerable weekly intake.

Accumulation and distribution of metallic elements and metalloids in edible Amanita fulva mushrooms.

Science.gov (United States)

Falandysz, Jerzy; Drewnowska, Małgorzata; Chudzińska, Maria; Barałkiewicz, Danuta

2017-03-01

Baseline concentrations of Ag, Al, As, Ba, Ca, Cd, Co, Cu, Cr, Fe, K, Mg, Mn, Na, Ni, P, Pb, Rb, Sr, Tl, V, U and Zn were presented in Amanita fulva collected from unpolluted areas in Poland. There is no previous data published on the bio-element constituents of A. fulva. A very narrow range of values was determined by ICP-DRC-MS and ICP-AES for the trace elements Ag, Co, Cu, Cr, Ni, Rb, Sr, Tl and Zn in caps and of Ag, Co, Cu, Mn, Ni, Sr, U and Zn in stipes and also for the macro elements K, P, Na and Mg. The fruitbodies of A. fulva from the northern (Baltic Sea coastal forests) and southwestern (Lower Silesia forests) sites differed substantially in cadmium, lead and uranium, and those from the Lower Silesia region showed them in greater concentrations. This observation may imply that A. fulva under typical geochemical site conditions is able to regulate the accumulation of many of the elements mentioned in fruiting bodies. Copyright © 2016 Elsevier Inc. All rights reserved.

Identification and characterization of a silencer regulatory element in the 3'-flanking region of the murine CD46 gene.

Science.gov (United States)

Nomura, M; Tsujimura, A; Begum, N A; Matsumoto, M; Wabiko, H; Toyoshima, K; Seya, T

2000-01-01

The murine membrane cofactor protein (CD46) gene is expressed exclusively in testis, in contrast to human CD46, which is expressed ubiquitously. To elucidate the mechanism of differential CD46 gene expression among species, we cloned entire murine CD46 genomic DNA and possible regulatory regions were placed in the flanking region of the luciferase reporter gene. The reporter gene assay revealed a silencing activity not in the promoter, but in the 3'-flanking region of the gene and the silencer-like element was identified within a 0.2-kb region between 0.6 and 0.8 kb downstream of the stop codon. This silencer-like element was highly similar to that of the pig MHC class-I gene. The introduction of a mutation into this putative silencer element of murine CD46 resulted in an abrogation of the silencing effect. Electrophoretic mobility-shift assay indicated the presence of the binding molecule(s) for this silencer sequence in murine cell lines and tissues. A size difference of the protein-silencer-element complex was observed depending upon the solubilizers used for preparation of the nuclear extracts. A mutated silencer sequence failed to interact with the binding molecules. The level of the binding factor was lower in the testicular germ cells compared with other organs. Thus the silencer element and its binding factor may play a role in transcriptional regulation of murine CD46 gene expression. These results imply that the effects of the CD46 silencer element encompass the innate immune and reproductive systems, and in mice may determine the testicular germ-cell-dominant expression of CD46. PMID:11023821

Relationships among developmental stage, metamorphic timing, and concentrations of elements in bullfrogs (Rana catesbeiana)

Energy Technology Data Exchange (ETDEWEB)

Snodgrass, J.W.; Hopkins, W.A.; Roe, J.H. [Towson University, Towson, MD (United States). Dept. for Biological Science

2003-07-01

We collected bullfrog (Rana catesbeiana) larvae from a coal combustion waste settling basin to investigate the effects of developmental stage and timing of metamorphosis on concentrations of a series of trace elements in bullfrog tissues. Bullfrogs at four stages of development (from no hind limbs to recently metamorphosed juveniles) and bullfrogs that metamorphosed in the fall or overwintered in the contaminated basin and metamorphosed in the spring were analyzed for whole-body concentrations of Al, V, Cr, Ni, Cu, As, Pb, Cd, Zn, Ag, Sr, and Se. After the effects of dry mass were removed, tissue concentrations of six elements (Al, V, Cr, Ni, Cu, As, and Pb) decreased from the late larval stage through metamorphosis. Decreases in concentrations through metamorphosis ranged from 40% for Cu to 97% for Al. Tissue concentrations of these elements were also similar or higher in spring; Al and Cr concentrations were 34 and 90% higher in the spring, respectively, whereas As, Ni, Cu, and Pb concentrations were {lt} 10% higher. Concentrations of Cd, Se, and Ag varied among seasons but not among stages; Cd and Ag concentrations were 40 and 62% lower, respectively, and Se concentrations were 21% higher in spring. Concentrations of Zn varied only among stages; concentrations decreased gradually through late larval stage and then increased through metamorphosis. Concentrations of Sr varied among stages, but this variation was dependent on the season. Concentrations of Sr were higher in larval stages during the spring, but because concentrations of Sr increased 122% through metamorphosis in the fall and only 22% in the spring, concentrations were higher in fall metamorphs when compared with spring metamorphs. Our results indicate that metamorphosis and season of metamorphosis affects trace element concentrations in bullfrogs and may have important implications for the health of juveniles and the transfer of pollutants from the aquatic to the terrestrial environment.

Defect complexes formed with Ag atoms in CDTE, ZnTe, and ZnSe

CERN Document Server

Wolf, H; Ostheimer, V; Hamann, J; Lany, S; Wichert, T

2000-01-01

Using the radioactive acceptor $^{111}\\!$Ag for perturbed $\\gamma$-$\\gamma$-angular correlation (PAC) spectroscopy for the first time, defect complexes formed with Ag are investigated in the II-VI semiconductors CdTe, ZnTe and ZnSe. The donors In, Br and the Te-vacancy were found to passivate Ag acceptors in CdTe via pair formation, which was also observed in In-doped ZnTe. In undoped or Sb-doped CdTe and in undoped ZnSe, the PAC experiments indicate the compensation of Ag acceptors by the formation of double broken bond centres, which are characterised by an electric field gradient with an asymmetry parameter close to h = 1. Additionally, a very large electric field gradient was observed in CdTe, which is possibly connected with residual impurities.

Synthesis, macroscopic and local probe characterization of AgCrO$_2$ and CdCr$_2$S$_4$

CERN Document Server

Oliveira, Gonçalo; Araujo, J P

The search of new materials with new and/or enhanced physical properties has, nowadays, a strict relation with the evolution of technology. The hunt for systems exhibiting simultaneous (anti)ferroelectric and (anti)ferromagnetic orders has re-started in the last years, and remains as one of the hot topics for Physic, Chemistry and Materials Science scientific communities. This is triggered by the possibility to apply these materials into, ${e.g.}$, new multiferroic memories that could be written electrically and read magnetically (or vice-versa). This thesis presents an experimental study on two of these so-called multiferroic materials, the AgCrO$_2$ delafossite and CdCr$_2$S$_4$ spinel type compounds. Different methods have been tested for the synthesis of delafossite silver chromium oxide AgCrO$_2$ namely, solid state reaction (ssr) and sol-gel combustion. The processes were optimized regarding complexing/combusting agents, temperature and duration of the heat treatments, as well as the processing atmosphe...

Bcl-xL regulates CD1d-mediated antigen presentation to NKT cells by altering CD1d trafficking through the endocytic pathway.

Science.gov (United States)

Subrahmanyam, Priyanka B; Carey, Gregory B; Webb, Tonya J

2014-09-01

NKT cells are a unique subset of T cells that recognize glycolipid Ags presented in the context of CD1d molecules. NKT cells mount strong antitumor responses and are a major focus in developing effective cancer immunotherapy. It is known that CD1d molecules are constantly internalized from the cell surface, recycled through the endocytic compartments, and re-expressed on the cell surface. However, little is known about the regulation of CD1d-mediated Ag processing and presentation in B cell lymphoma. Prosurvival factors of the Bcl-2 family, such as Bcl-xL, are often upregulated in B cell lymphomas and are intimately linked to sphingolipid metabolism, as well as the endocytic compartments. We hypothesized that Bcl-xL can regulate CD1d-mediated Ag presentation to NKT cells. We found that overexpression or induction of Bcl-xL led to increased Ag presentation to NKT cells. Conversely, the inhibition or knockdown of Bcl-xL led to decreased NKT cell activation. Furthermore, knockdown of Bcl-xL resulted in the loss of CD1d trafficking to lysosome-associated membrane protein 1(+) compartments. Rab7, a late endosomal protein, was upregulated and CD1d molecules accumulated in the Rab7(+) late endosomal compartment. These results demonstrate that Bcl-xL regulates CD1d-mediated Ag processing and presentation to NKT cells by altering the late endosomal compartment and changing the intracellular localization of CD1d. Copyright © 2014 by The American Association of Immunologists, Inc.

Concentration of stable elements in food products

International Nuclear Information System (INIS)

Montford, M.A.; Shank, K.E.; Hendricks, C.; Oakes, T.W.

1980-01-01

Food samples were taken from commercial markets and analyzed for stable element content. The concentrations of most stable elements (Ag, Al, As, Au, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Cu, Fe, Hf, I, K, La, Mg, Mn, Mo, Na, Rb, Sb, Sc, Se, Sr, Ta, Th, Ti, V, Zn, Zr) were determined using multiple-element neutron activation analysis, while the concentrations of other elements (Cd, Hg, Ni, Pb) were determined using atomic absorption. The relevance of the concentrations found are noted in relation to other literature values. An earlier study was extended to include the determination of the concentration of stable elements in home-grown products in the vicinity of the Oak Ridge National Laboratory. Comparisons between the commercial and local food-stuff values are discussed

Determination of trace elements in wool fibre by instrumental neutron activation analysis and relation between trace element contents and quality of wool

International Nuclear Information System (INIS)

Eozyol, H.

1990-01-01

Wool samples were analyzed by neutron activation analysis and 17 elements, Al, Ag, Au, As, Br, Ca, Co, Cr, Cu, Fe, La, Mg, Mn, Na, Sb, Se and Zn were measured quantitatively. The presence of seven others, Ce, Eu, I, Mo, Te and W was noted. Since several elements, such as Cd, Hg and Pb could not be conveniently determined by NAA, Atomic Absorption Spectroscopy (AAS) was used instead. Cu and Zn were also analyzed by NAA and AAS to compare these two methods. Mechanical properties of samples were measured and the relations between the trace element contents and properties were investigated. (author) 16 refs.; 7 tabs

Comparison of the concentrations of metal elements and isotopes of lead found in rice and rice bran.

Science.gov (United States)

Dai, Shouhui; Yang, Hui; Yang, Lan; Wang, Fuhua; Du, Ruiying; Wen, Dian

2014-08-01

Very few studies have investigated the difference in the distribution of metal elements between rice and rice bran samples. In this study, the concentrations of 27 metal elements (Li, Be, Na, Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Ag, Cd, Cs, Ba, Tl, Pb, and U) in 56 polished rice and their corresponding bran samples were determined. A significant difference in concentrations of all elements except Ag and Cd was found between rice and bran (P rice ratios of 1.21 to 36.3. High concentrations of metal elements, especially that of the heavy metal Cr, in bran samples present a potential safety issue for bran products, such as food and feed containing bran. Pb isotope ((204)Pb, (206)Pb, (207)Pb, and (208)Pb) ratios also were determined. The (206)Pb/(207)Pb and (208)Pb/(207)Pb ratios in bran were generally higher than those in rice (P rice and bran samples were distinctly different from each other, indicating that Pb isotope composition is an effective for discriminating between bran and rice samples.

First principles-based adsorption comparison of group IV elements (C, Si, Ge, and Sn) on Au(111)/Ag(111) surface

International Nuclear Information System (INIS)

Chakraborty, Sudip; Rajesh, Ch.

2012-01-01

We have reported a first-principle investigation of the structural properties of monomer and dimer for group IV elements (C, Si, Ge, and Sn) adsorbed on the Au(111) and Ag(111) surfaces. The calculations were performed by means of a plane wave based pseudopotential method under the framework of density functional theory. The results reveal the preference of adatom to be adsorbed on the hexagonal closed packed site of the metal (111) surfaces with strong binding energy. The structures introduce interlayer forces in the adsorbate. The strong bonding with the surface atoms is a result of p–d hybridization. The adsorption energy follows a sequence as one goes down in the group IV elements which imply that the interaction of the group IV elements with Au/Ag is decreasing as the atomic number increases.

GM-CSF/IL-3/IL-5 receptor common β chain (CD131 expression as a biomarker of antigen-stimulated CD8+ T cells

Directory of Open Access Journals (Sweden)

Maric Dragan

2008-04-01

Full Text Available Abstract Background Upon Ag-activation cytotoxic T cells (CTLs produce IFN-γ GM-CSF and TNF-α, which deliver simultaneously pro-apoptotic and pro-inflammatory signals to the surrounding microenvironment. Whether this secretion affects in an autocrine loop the CTLs themselves is unknown. Methods Here, we compared the transcriptional profile of Ag-activated, Flu-specific CTL stimulated with the FLU M1:58-66 peptide to that of convivial CTLs expanded in vitro in the same culture. PBMCs from 6 HLA-A*0201 expressing donors were expanded for 7 days in culture following Flu M1:58-66 stimulation in the presence of 300 IU/ml of interleukin-2 and than sorted by high speed sorting to high purity CD8+ expressing T cells gated according to FluM1:58-66 tetrameric human leukocyte antigen complexes expression. Results Ag-activated CTLs displayed higher levels of IFN-γ, GM-CSF (CSF2 and GM-CSF/IL-3/IL-5 receptor common β- chain (CD131 but lacked completely expression of IFN-γ receptor-II and IFN-stimulated genes (ISGs. This observation suggested that Ag-activated CTLs in preparation for the release of IFN-γ and GM-CSF shield themselves from the potentially apoptotic effects of the former entrusting their survival to GM-SCF. In vitro phenotyping confirmed the selective surface expression of CD131 by Ag-activated CTLs and their increased proliferation upon exogenous administration of GM-CSF. Conclusion The selective responsiveness of Ag-activated CTLs to GM-CSF may provide an alternative explanation to the usefulness of this chemokine as an adjuvant for T cell aimed vaccines. Moreover, the selective expression of CD131 by Ag-activated CTLs proposes CD131 as a novel biomarker of Ag-dependent CTL activation.

ADCC-Mediated CD56DIM NK Cell Responses Are Associated with Early HBsAg Clearance in Acute HBV Infection.

Science.gov (United States)

Yu, Wen-Han; Cosgrove, Cormac; Berger, Christoph T; Cheney, Patrick C; Krykbaeva, Marina; Kim, Arthur Y; Lewis-Ximenez, Lia; Lauer, Georg M; Alter, Galit

2018-01-01

Hepatitis B virus (HBV) affects up to 400 million people worldwide and accounts for approximately one million deaths per year from liver pathologies. Current treatment regimens are effective in suppressing viremia but usually have to be taken indefinitely, warranting research into new therapeutic approaches. Acute HBV infection in adults almost universally results in resolution of viremia, with the exception of immunocompromised persons, suggesting that the immune response can functionally cure or even eradicate HBV infection. Because immunophenotypic and functional studies have implicated a role for Natural Killer (NK) cells in HBV clearance during acute infection, we hypothesized that a distinct NK-cell profile exists in acute HBV infection that could provide information for the mechanism of HBV clearance. Using multivariate flow cytometry, we evaluated the expression of key activating and inhibitory receptors on NK cells, and their ability to respond to classic target cell lines. Multivariate analysis revealed selective perturbation of the CD56 dim NK-cell subset during acute infection, displaying low levels of NKp46+, NKp30+, CD160+ and CD161+ cells. Intriguingly, the CD56 dim NK-cell profile predicted time to HBV surface antigen (HBsAg) clearance from the blood, and distinct NK-cell profiles predicted early (NKp30, CD94, CD161) and late clearance (KIR3DL1, CD158a, perforin, NKp46). Finally, functional analysis demonstrated that early and late clearance tracked with elevated degranulation (CD107a) or IFNγ production, respectively, in response to ADCC-mediated activation. The cytolytic CD56 dim NK-cell subset is selectively activated in acute HBV infection and displays distinct phenotypic and functional profiles associated with efficient and early control of HBV, implicating antibody-mediated cytolytic NK-cell responses in the early control and functional cure of HBV infection.

Systemic immunological tolerance to ocular antigens is mediated by TRAIL-expressing CD8+ T cells.

Science.gov (United States)

Griffith, Thomas S; Brincks, Erik L; Gurung, Prajwal; Kucaba, Tamara A; Ferguson, Thomas A

2011-01-15

Systemic immunological tolerance to Ag encountered in the eye restricts the formation of potentially damaging immune responses that would otherwise be initiated at other anatomical locations. We previously demonstrated that tolerance to Ag administered via the anterior chamber (AC) of the eye required Fas ligand-mediated apoptotic death of inflammatory cells that enter the eye in response to the antigenic challenge. Moreover, the systemic tolerance induced after AC injection of Ag was mediated by CD8(+) regulatory T cells. This study examined the mechanism by which these CD8(+) regulatory T cells mediate tolerance after AC injection of Ag. AC injection of Ag did not prime CD4(+) T cells and led to increased TRAIL expression by splenic CD8(+) T cells. Unlike wild-type mice, Trail(-/-) or Dr5(-/-) mice did not develop tolerance to Ag injected into the eye, even though responding lymphocytes underwent apoptosis in the AC of the eyes of these mice. CD8(+) T cells from Trail(-/-) mice that were first injected via the AC with Ag were unable to transfer tolerance to naive recipient wild-type mice, but CD8(+) T cells from AC-injected wild-type or Dr5(-/-) mice could transfer tolerance. Importantly, the transferred wild-type (Trail(+/+)) CD8(+) T cells were also able to decrease the number of infiltrating inflammatory cells into the eye; however, Trail(-/-) CD8(+) T cells were unable to limit the inflammatory cell ingress. Together, our data suggest that "helpless" CD8(+) regulatory T cells generated after AC injection of Ag enforce systemic tolerance in a TRAIL-dependent manner to inhibit inflammation in the eye.

[Relationship between HBeAg from HBsAg positive mothers and regulatory T cells in neonates and its influence on HBV intrauterine transmission].

Science.gov (United States)

Hao, H Y; Yang, Z Q; Xu, X X; Wang, X F; Wang, B; Shi, X H; Fu, Z D; Wang, B; Wang, S P

2017-10-10

Objective: To explore the relationship between HBeAg in HBsAg positive mothers and CD(4)(+)CD(25)(+) Foxp3 (+)regulatory T cells (Treg) in newborns, as well as how they would influence the increasing risk on HBV intrauterine transmission. Methods: We collected information on general demographic characteristics and delivery on 270 HBsAg positive mothers and their newborns from the Third People's Hospital of Taiyuan. Fluorescence quantitative polymerase chain reaction (FQ-PCR) and chemiluminescence immunoassay (CLIA) were used to detect HBV DNA and HBV serological markers in peripheral blood from both mothers and neonates. The expression of Treg and other immune cells in peripheral blood of neonates were detected with flow cytometry (FCM). Results: Maternal HBeAg positive rates were associated with an increased risk of intrauterine transmission ( OR =4.08, 95 %CI : 1.89-8.82). Rates of Treg in newborns born to HBsAg-positive mothers were higher than that of the negative group ( Z =2.29, P =0.022). Each pair of the subjects was assigned to five different groups according to the HBeAg titers of mothers. Frequencies of both Treg and HBeAg in newborns and HBV DNA in mothers between the above said 5 groups showed similar trends of changing patterns and the differences between groups were statistically significant(χ(2)=18.73, P mother's HBeAg titers were positively related to the percentage of Treg in their newborns ( r(s) =0.19, P =0.039). In addition, the frequencies of Treg were negatively correlated with pDC and CD(4)(+) T cell in their newborns ( r(s) =-0.21, P =0.017; r(s) =-0.23, P =0.009). Conclusion: HBeAg from HBsAg positive mothers might have inhibited the function of neonatal DC cells and T cells to reduce the immune response to HBV by up-regulating the proportion of Treg and finally increased the risk of HBV intrauterine transmission.

Crystal structures of [SbF{sub 6}]{sup -} salts of di- and tetrahydrated Ag{sup +}, tetrahydrated Pd{sup 2+} and hexahydrated Cd{sup 2+} cations

Energy Technology Data Exchange (ETDEWEB)

Mazej, Zoran; Goreshnik, Evgeny [Jozef Stefan Institute, Ljubljana (Slovenia). Dept. of Inorganic Chemistry and Technology

2017-07-01

The [Ag(H{sub 2}O){sub 2}]SbF{sub 6}, is triclinic, P anti 1 (No. 2), with a=6.6419(3) Aa, b=7.6327(3) Aa, c=11.1338(3) Aa, α=95.492(3) , β=96.994(3) , γ=113.535(4) , V=507.13(4) Aa{sup 3} at 150 K, and Z=3. There are two crystallographically non-equivalent Ag{sup +} cations. The Ag1 is coordinated by two water molecules with Ag-OH{sub 2} distances equal to 2.271(2) Aa forming in that way a discrete linear [Ag(H{sub 2}O){sub 2}]{sup +} cation. Additionaly, it forms two short Ag..F contacts (2.630(2) Aa), resulting in AgO{sub 2}F{sub 2} plaquette, and four long ones (2 x 3.001(2) Aa and 2 x 3.095(2) Aa) with fluorine atoms located below and above the AgO{sub 2}F{sub 2} plaquette. The H{sub 2}O molecules bridge Ag2 atoms into {-[Ag(μ-OH_2)_2]-}{sub n} infinite chains, with Ag-O distances of 2.367(2)-2.466(2) Aa. The [Pd(H{sub 2}O){sub 4}](SbF{sub 6}){sub 2}.4H{sub 2}O is monoclinic, P2{sub 1}/a (No.14), with a=8.172(2) Aa, b=13.202(3) Aa, c=8.188(3) Aa, β=115.10(1) , V=799.9(4) Aa{sup 3} at 200 K, and Z=2. Its crystal structure can be described as an alternation of layers of [Pd(H{sub 2}O){sub 4}]{sup 2+} cations (interconnected by H{sub 2}O molecules) and [SbF{sub 6}]{sup -} anions. It represents the first example where [Pd(H{sub 2}O){sub 4}]{sup 2+} has been structurally determined in the solid state. Four oxygen atoms provided by H{sub 2}O molecules are in almost ideal square-planar arrangement with Pd-O bond lengths 2 x 2.004(5) Aa and 2 x 2.022(6) Aa. The [Cd(H{sub 2}O){sub 6}](SbF{sub 6}){sub 2}, is orthorhombic, Pnnm (No.58), with a=5.5331(2) Aa, b=14.5206(4) Aa, c=8.9051(3) Aa, V=715.47(4) Aa{sup 3} at 200 K, and Z=2. It consists of [Cd(H{sub 2}O){sub 6}]{sup 2+} cations and [SbF{sub 6}]{sup -} anions.

Retention of Ag-specific memory CD4+ T cells in the draining lymph node indicates lymphoid tissue resident memory populations.

Science.gov (United States)

Marriott, Clare L; Dutton, Emma E; Tomura, Michio; Withers, David R

2017-05-01

Several different memory T-cell populations have now been described based upon surface receptor expression and migratory capabilities. Here we have assessed murine endogenous memory CD4 + T cells generated within a draining lymph node and their subsequent migration to other secondary lymphoid tissues. Having established a model response targeting a specific peripheral lymph node, we temporally labelled all the cells within draining lymph node using photoconversion. Tracking of photoconverted and non-photoconverted Ag-specific CD4 + T cells revealed the rapid establishment of a circulating memory population in all lymph nodes within days of immunisation. Strikingly, a resident memory CD4 + T cell population became established in the draining lymph node and persisted for several months in the absence of detectable migration to other lymphoid tissue. These cells most closely resembled effector memory T cells, usually associated with circulation through non-lymphoid tissue, but here, these cells were retained in the draining lymph node. These data indicate that lymphoid tissue resident memory CD4 + T-cell populations are generated in peripheral lymph nodes following immunisation. © 2017 The Authors. European Journal of Immunology published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation on the toxicity of nanoAg to bovine serum albumin

Energy Technology Data Exchange (ETDEWEB)

Liu Rutao, E-mail: rutaoliu@sdu.edu.cn [School of Environmental Science and Engineering, Shandong University, 27 Shanda South Road, Jinan 250100 (China); Sun Feng; Zhang Lijun; Zong Wansong; Zhao Xingchen; Wang Li; Wu Ruolin [School of Environmental Science and Engineering, Shandong University, 27 Shanda South Road, Jinan 250100 (China); Hao Xiaopeng [State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100 (China)

2009-06-15

Measuring protein damage by nanomaterials may give insight into the mechanisms of toxicity of nanomaterials. The toxic effects of nanoAg on bovine serum albumin (BSA) were thoroughly studied using fluorescence spectroscopy, ultraviolet-visible absorption spectroscopy, resonance light scattering spectroscopy (RLS), circular dichroism spectroscopy (CD) and transmission electron microscopy (TEM). NanoAg had obvious toxic effects on BSA: nanoAg could increase the amount of helix and decrease the beta sheet structure, leading to a loosening of the protein skeleton. In the loose structure, internal hydrophobic amino acids are exposed and the characteristic fluorescence of BSA is obviously quenched. When the ratio of nanoAg and BSA increased to 1: 96 (wt/wt), the impact of nanoAg on the spectral properties leveled off. The RLS spectrum, TEM, CD spectra and electrophoresis results showed that BSA had destroyed the double-layer structure of nanoAg and covered its surface, generating a BSA-nanoAg complex held together by van der Waals and electrostatic forces. This paper provides a new perspective and method for determining the toxic effects of nanoAg on biological macromolecules.

Dynamic analysis of CD127 expression on memory CD8 T cells from patients with chronic hepatitis B during telbivudine treatment

Directory of Open Access Journals (Sweden)

Lv Guocai

2010-08-01

Full Text Available Abstract Background Accumulating evidence supports the theory that expression of CD127 on CD8 T cells during the process of antiviral immune response indicates a subset of effect CD8 T cells that successfully develop into fully protective memory. CD8 T cells expression of CD127 may be used as a predictor to evaluate disease status in chronic viral infection. The aim of this study was to investigate the CD127 expression level on different subsets of CD8 T cell and explore the relationship between CD127 expression on CD8 memory T cells and serum hepatitis B virus (HBV DNA and hepatitis B e antigen (HBeAg levels in patients with chronic hepatitis B (CHB. We also aimed to investigate the CD127 expression pattern on CD8 memory T cells of CHB patients who were treated with Telbivudine. Methods/Results Twenty HBeAg-positive CHB patients were selected and treated with telbivudine 600 mg/day for 48 weeks. The memory CD8 T cells were characterized by expression of CD45RA and CD27 markers. CD127 expression on the CD8 T-cell surface was measured by four-colour flow cytometry. Our results showed that CD127 expression on memory CD8 T cells was reduced in CHB patients. There was a strong negative correlation between CD127 expression on memory CD8 T cells and serum HBV DNA and HBeAg levels in CHB patients. Moreover, successful antiviral therapy increased CD127 expression on CD8 memory T cells as well as on HBV-specific CD8 T cells in CHB patients. Conclusion These results suggest that diminished CD127 expression on CD8 memory T cells of CHB patients is a potential mechanism explaining cellular immune function impairment in CHB infection, and that CD127 expression on CD8 memory T cells is a useful indicator for evaluating the effects of anti-HBV therapy.

Electrical parameters of metal doped n-CdO/p-Si heterojunction diodes

Energy Technology Data Exchange (ETDEWEB)

Umadevi, P. [Department of Physics, Sri Vidya College of Engineering & Technology, Virudhunagar 626005, Tamilnadu (India); Prithivikumaran, N., E-mail: janavi_p@yahoo.com [Nanoscience Research Lab, Department of Physics, VHNSN College, Virudhunagar 626001, Tamilnadu (India)

2016-11-15

The CdO, Al doped CdO and Cu doped CdO thin films were coated on p-type silicon substrates by sol–gel spin coating method. The structural, surface morphological and electrical properties of undoped, Al and Cu doped CdO films on silicon substrate were studied. The Ag/CdO/p-Si, Ag/Al: CdO/p-Si and Ag/Cu: CdO/p-Si heterojunction diodes were fabricated and the diode parameters such as reverse saturation current, barrier height and ideality factor of the diodes were investigated by current–voltage (I–V)characteristics. The reverse current of the diode was found to increase strongly with the doping. The values of barrier height and ideality factor were decreased by doping with aluminium and copper. Photo response of the heterojunction diodes was studied and it was found that, the heterojunction diode constructed with the doped CdO has larger Photo response than the undoped heterojunction diode.

The effect of TiO2 and Ag nanoparticles on reproduction and development of Drosophila melanogaster and CD-1 mice

International Nuclear Information System (INIS)

Philbrook, Nicola A.; Winn, Louise M.; Afrooz, A.R.M. Nabiul; Saleh, Navid B.; Walker, Virginia K.

2011-01-01

In the last two decades, nanoparticles (NPs) have found applications in a wide variety of consumer goods. Titanium dioxide (TiO 2 ) and silver (Ag) NPs are both found in cosmetics and foods, but their increasing use is of concern due to their ability to be taken up by biological systems. While there are some reports of TiO 2 and Ag NPs affecting complex organisms, their effects on reproduction and development have been largely understudied. Here, the effects of orally administered TiO 2 or Ag NPs on reproduction and development in two different model organisms were investigated. TiO 2 NPs reduced the developmental success of CD-1 mice after a single oral dose of 100 or 1000 mg/kg to dams, resulting in a statistically significant increase in fetal deformities and mortality. Similarly, TiO 2 NP addition to food led to a significant progeny loss in the fruit fly, Drosophila, as shown by a decline in female fecundity. Ag NP administration resulted in an increase in the mortality of fetal mice. Similarly in Drosophila, Ag NP feeding led to a significant decrease in developmental success, but unlike TiO 2 NP treatment, there was no decline in fecundity. The distinct response associated with each type of NP likely reflects differences in NP administration as well as the biology of the particular model. Taken together, however, this study warns that these common NPs could be detrimental to the reproductive and developmental health of both invertebrates and vertebrates.

Role of 4-1BB receptor in the control played by CD8(+ T cells on IFN-gamma production by Mycobacterium tuberculosis antigen-specific CD4(+ T Cells.

Directory of Open Access Journals (Sweden)

Carla Palma

Full Text Available BACKGROUND: Antigen-specific IFN-gamma producing CD4(+ T cells are the main mediators of protection against Mycobacterium tuberculosis infection both under natural conditions and following vaccination. However these cells are responsible for lung damage and poor vaccine efficacy when not tightly controlled. Discovering new tools to control nonprotective antigen-specific IFN-gamma production without affecting protective IFN-gamma is a challenge in tuberculosis research. METHODS AND FINDINGS: Immunization with DNA encoding Ag85B, a candidate vaccine antigen of Mycobacterium tuberculosis, elicited in mice a low but protective CD4(+ T cell-mediated IFN-gamma response, while in mice primed with DNA and boosted with Ag85B protein a massive increase in IFN-gamma response was associated with loss of protection. Both protective and non-protective Ag85B-immunization generated antigen-specific CD8(+ T cells which suppressed IFN-gamma-secreting CD4(+ T cells. However, ex vivo ligation of 4-1BB, a member of TNF-receptor super-family, reduced the massive, non-protective IFN-gamma responses by CD4(+ T cells in protein-boosted mice without affecting the low protective IFN-gamma-secretion in mice immunized with DNA. This selective inhibition was due to the induction of 4-1BB exclusively on CD8(+ T cells of DNA-primed and protein-boosted mice following Ag85B protein stimulation. The 4-1BB-mediated IFN-gamma inhibition did not require soluble IL-10, TGF-beta, XCL-1 and MIP-1beta. In vivo Ag85B stimulation induced 4-1BB expression on CD8(+ T cells and in vivo 4-1BB ligation reduced the activation, IFN-gamma production and expansion of Ag85B-specific CD4(+ T cells of DNA-primed and protein-boosted mice. CONCLUSION/SIGNIFICANCE: Antigen-specific suppressor CD8(+ T cells are elicited through immunization with the mycobacterial antigen Ag85B. Ligation of 4-1BB receptor further enhanced their suppressive activity on IFN-gamma-secreting CD4(+ T cells. The selective

Radiotracer studies on radionuclide and trace element cycling in corals

International Nuclear Information System (INIS)

Fowler, S.W.; Teyssie, J.L.; Acosta, A.; Gattuso, J.P.; Jaubert, J.

1999-01-01

Microcosm experiments were designed in which microcolonies of three coral species were exposed to gamma-emitting radiotracers of trace metals and radionuclides ( 110 Am, 109 Cd. 57 Cocyanocobalamin, 110 Ag, 134 Cs, 65 Zn, 60 Co, 75 Se, 85 Sr, 133 Ba, 54 Mn) to determine uptake and loss as well as distribution in tissue, skeleton and zooxanthellae. Following a seven day exposure in seawater, the degree of uptake (CF = concentration factor) for a given element was highly dependent on species. The highest CF s , in whole colonies were found for 100m Ag(82-172), 57 Co (68-124) and 65 Zn (41-52); the lowest CF s , were noted for the soluble radionuclides Cs (1-2) and Sr (2-9). Low CF s , were recorded in skeleton and increased by roughly an order of magnitude between skeleton, tissue and zooxanthellae. 241 Am is readily taken up by dead skeleton (CF=31-49), whereas in living corals it is preferentially accumulated by the tissue (CF=51-120) which acts as a partial barrier against contamination of the internal skeleton (CF=6-10). The chemical species of the element can also affect uptake by corals, as evidenced by the order of magnitude greater bioaccumulation of organic cobalt compared to the inorganic form in tissues. Once accumulated, some of the elements tested (e.g. Cd, Co) are strongly retained with biological half-lives as long as several months

Large-scale spatial and interspecies differences in trace elements and stable isotopes in marine wild fish from Chinese waters

International Nuclear Information System (INIS)

Zhang, Wei; Wang, Wen-Xiong

2012-01-01

Highlights: ► A large-scale study on trace element levels in marine wild fish from Chinese waters. ► Spatial variation found for Al, As, Cd, Cr, Fe, Ni, Pb, but not for Ag, Cu, Mo, Se and Zn. ► The Pearl River Estuary contained the highest concentrations of Al, Cr, Ni, and Pb. ► No biomagnification occurred for any of the trace elements studied in marine fish. ► No obvious health risk from the intake of trace elements through fish consumption. - Abstract: We conducted a large scale investigation of twelve trace element levels and stable isotopes (δ 13 C and δ 15 N) in twenty-nine marine wild fish species collected from Chinese coastal waters. Trace element levels varied significantly with species. Clear spatial variations were found for Al, As, Cd, Cr, Fe, Ni, and Pb, whereas Ag, Cu, Mo, Se and Zn did not show much spatial variation. The Pearl River Estuary contained the highest concentrations of Al, Cr, Ni, and Pb, whereas the most southern waters (Haikou) contained the lowest concentrations of Al, Fe, and Pb. There was no correlation between log-transformed trace elements concentrations and δ 15 N values or δ 13 C values, indicating no biomagnification among these trace elements. The calculated hazard quotients (HQ) of 10 elements were less than 1, thus there was no obvious health risk from the intake of trace elements through marine wild fish consumption.

Temperature dependence of the electric field gradient in AgPd and AgPt alloys

International Nuclear Information System (INIS)

Krolas, K.

1977-07-01

The measurements of temperature dependence of the electric field gradient (EFG) on 111 Cd nuclei in AgPd and AgPt alloys were performed using the time dependent perturbed angular correlation method. The EFG caused by impurities distributed in further coordination shells decrease stronaer with increasing temperature than the EFG due to single impurity being the nearest neighbour of the probe atom. These results were explained assuming different modes of thermal vibrations of single impurity atoms and impurity complexes in silver host lattice. (author)

In situ synthesis of CdS/CdWO4/WO3 heterojunction films with enhanced photoelectrochemical properties

Science.gov (United States)

Zhan, Faqi; Li, Jie; Li, Wenzhang; Yang, Yahui; Liu, Wenhua; Li, Yaomin

2016-09-01

CdS/CdWO4/WO3 heterojunction films on fluorine-doped tin oxide (FTO) substrates are for the first time prepared as an efficient photoanode for photoelectrochemical (PEC) hydrogen generation by an in situ conversion process. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet visible spectrometry (UV-vis) and X-ray photoelectron spectroscopy (XPS). The CdS hollow spheres (∼80 nm) sensitized WO3 plate film with a CdWO4 buffer-layer exhibits increased visible light absorption and a significantly improved photoelectrochemical performance. The photocurrent density at 0 V (vs. Ag/AgCl) of the CdS/CdWO4/WO3 anode is ∼3 times higher than that of the CdWO4/WO3 anode, and ∼9 times higher than that of pure WO3 under illumination. The highest incident-photon-to-current-efficiency (IPCE) value increased from 16% to 63% when the ternary heterojunction was formed. This study demonstrates that the synthesis of ternary composite photocatalysts by the in situ conversion process may be a promising approach to achieve high photoelectric conversion efficiency.

Myeloid antigens in childhood lymphoblastic leukemia:clinical data point to regulation of CD66c distinct from other myeloid antigens

Directory of Open Access Journals (Sweden)

Madzo Jozef

2005-04-01

Full Text Available Abstract Background Aberrant expression of myeloid antigens (MyAgs on acute lymphoblastic leukemia (ALL cells is a well-documented phenomenon, although its regulating mechanisms are unclear. MyAgs in ALL are interpreted e.g. as hallmarks of early differentiation stage and/or lineage indecisiveness. Granulocytic marker CD66c – Carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6 is aberrantly expressed on ALL with strong correlation to genotype (negative in TEL/AML1 and MLL/AF4, positive in BCR/ABL and hyperdiploid cases. Methods In a cohort of 365 consecutively diagnosed Czech B-precursor ALL patients, we analyze distribution of MyAg+ cases and mutual relationship among CD13, CD15, CD33, CD65 and CD66c. The most frequent MyAg (CD66c is studied further regarding its stability from diagnosis to relapse, prognostic significance and regulation of surface expression. For the latter, flow cytometry, Western blot and quantitative RT-PCR on sorted cells is used. Results We show CD66c is expressed in 43% patients, which is more frequent than other MyAgs studied. In addition, CD66c expression negatively correlates with CD13 (p Conclusion In contrast to general notion we show that different MyAgs in lymphoblastic leukemia represent different biological circumstances. We chose the most frequent and tightly genotype-associated MyAg CD66c to show its stabile expression in patients from diagnosis to relapse, which differs from what is known on the other MyAgs. Surface expression of CD66c is regulated at the gene transcription level, in contrast to previous reports.

The effect of TiO{sub 2} and Ag nanoparticles on reproduction and development of Drosophila melanogaster and CD-1 mice

Energy Technology Data Exchange (ETDEWEB)

Philbrook, Nicola A., E-mail: 3nap@queensu.ca [School of Environmental Studies, Biosciences Complex, Queen' s University, 116 Barrie Street, Kingston, Ontario, Canada K7L 3N6 (Canada); Department of Biomedical and Molecular Sciences, Botterell Hall, 5th Floor, Queen' s University, 18 Stuart Street, Kingston, Ontario, Canada K7L 3N6 (Canada); Winn, Louise M., E-mail: winnl@queensu.ca [School of Environmental Studies, Biosciences Complex, Queen' s University, 116 Barrie Street, Kingston, Ontario, Canada K7L 3N6 (Canada); Department of Biomedical and Molecular Sciences, Botterell Hall, 5th Floor, Queen' s University, 18 Stuart Street, Kingston, Ontario, Canada K7L 3N6 (Canada); Afrooz, A.R.M. Nabiul [Department of Civil and Environmental Engineering, University of South Carolina, 300 Main Street, Columbia, SC 29208 (United States); Saleh, Navid B., E-mail: salehn@cec.sc.edu [Department of Civil and Environmental Engineering, University of South Carolina, 300 Main Street, Columbia, SC 29208 (United States); Walker, Virginia K., E-mail: walkervk@queensu.ca [School of Environmental Studies, Biosciences Complex, Queen' s University, 116 Barrie Street, Kingston, Ontario, Canada K7L 3N6 (Canada); Department of Biology, Biosciences Complex, Queen' s University, 116 Barrie Street, Kingston, Ontario, Canada K7L 3N6 (Canada)

2011-12-15

In the last two decades, nanoparticles (NPs) have found applications in a wide variety of consumer goods. Titanium dioxide (TiO{sub 2}) and silver (Ag) NPs are both found in cosmetics and foods, but their increasing use is of concern due to their ability to be taken up by biological systems. While there are some reports of TiO{sub 2} and Ag NPs affecting complex organisms, their effects on reproduction and development have been largely understudied. Here, the effects of orally administered TiO{sub 2} or Ag NPs on reproduction and development in two different model organisms were investigated. TiO{sub 2} NPs reduced the developmental success of CD-1 mice after a single oral dose of 100 or 1000 mg/kg to dams, resulting in a statistically significant increase in fetal deformities and mortality. Similarly, TiO{sub 2} NP addition to food led to a significant progeny loss in the fruit fly, Drosophila, as shown by a decline in female fecundity. Ag NP administration resulted in an increase in the mortality of fetal mice. Similarly in Drosophila, Ag NP feeding led to a significant decrease in developmental success, but unlike TiO{sub 2} NP treatment, there was no decline in fecundity. The distinct response associated with each type of NP likely reflects differences in NP administration as well as the biology of the particular model. Taken together, however, this study warns that these common NPs could be detrimental to the reproductive and developmental health of both invertebrates and vertebrates.

Identification of a candidate CD5 homologue in the amphibian Xenopus laevis.

Science.gov (United States)

Jürgens, J B; Gartland, L A; Du Pasquier, L; Horton, J D; Göbel, T W; Cooper, M D

1995-11-01

We identified a novel T cell Ag in the South African clawed toad (Xenopus laevis) by a mAb designated 2B1. This Ag is present in relatively high levels on most thymocytes, approximately 65% of splenocytes, 55% of PBL, and 65% of intestinal lymphocytes, but is rarely seen on IgM+ B cells in any of these tissues. Lymphocytes bearing the 2B1 Ag proliferate in response to stimulation with Con A or PHA, whereas the 2B1- lymphocytes are reactive to LPS. Biochemical analysis indicates that this Ag is a differentially phosphorylated glycoprotein of 71 to 82 kDa. The protein core of 64 kDa bears both N- and O-linked carbohydrate side chains. The amino-terminal protein sequence of the 2B1 Ag shares significant homology with both the macrophage scavenger receptor type 1 motif and the mammalian CD5/CD6 family. The biochemical characteristics and cellular distribution of the 2B1 Ag suggest that it represents the CD5 homologue in X. laevis. While T cells constitutively express this highly conserved molecule, Xenopus B cells acquire the CD5 homologue only when they are stimulated in the presence of T cells.

Target Antigen Density Governs the Efficacy of Anti-CD20-CD28-CD3 zeta Chimeric Antigen Receptor-Modified Effector CD8(+) T Cells

NARCIS (Netherlands)

Watanabe, Keisuke; Terakura, Seitaro; Martens, Anton C.; van Meerten, Tom; Uchiyama, Susumu; Imai, Misa; Sakemura, Reona; Goto, Tatsunori; Hanajiri, Ryo; Imahashi, Nobuhiko; Shimada, Kazuyuki; Tomita, Akihiro; Kiyoi, Hitoshi; Nishida, Tetsuya; Naoe, Tomoki; Murata, Makoto

2015-01-01

The effectiveness of chimeric Ag receptor (CAR)-transduced T (CAR-T) cells has been attributed to supraphysiological signaling through CARs. Second-and later-generation CARs simultaneously transmit costimulatory signals with CD3 zeta signals upon ligation, but may lead to severe adverse effects

Concentration and subcellular distribution of trace elements in liver of small cetaceans incidentally caught along the Brazilian coast

Energy Technology Data Exchange (ETDEWEB)

Kunito, Takashi; Nakamura, Shinji; Ikemoto, Tokutaka; Anan, Yasumi; Kubota, Reiji; Tanabe, Shinsuke; Rosas, Fernando C.W.; Fillmann, Gilberto; Readman, James W

2004-10-01

Concentrations of trace elements (V, Cr, Mn, Fe, Co, Cu, Zn, Ga, As, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, T-Hg, Org-Hg, Tl and Pb) were determined in liver samples of estuarine dolphin (Sotalia guianensis; n=20), Franciscana dolphin (Pontoporia blainvillei; n=23), Atlantic spotted dolphin (Stenella frontalis; n=2), common dolphin (Delphinus capensis; n=1) and striped dolphin (Stenella coeruleoalba; n=1) incidentally caught along the coast of Sao Paulo State and Parana State, Brazil, from 1997 to 1999. The hepatic concentrations of trace elements in the Brazilian cetaceans were comparable to the data available in literature on marine mammals from Northern Hemisphere. Concentrations of V, Se, Mo, Cd, T-Hg and Org-Hg increased with increasing age in liver of both estuarine and Franciscana dolphins. Very high concentrations of Cu (range, 262-1970 {mu}g/g dry wt.) and Zn (range, 242-369 {mu}g/g dry wt.) were observed in liver of sucklings of estuarine dolphin. Hepatic concentrations of V, Se, T-Hg, Org-Hg and Pb were significantly higher in estuarine dolphin, whereas Franciscana dolphin showed higher concentrations of Mn, Co, As and Rb. Ratio of Org-Hg to T-Hg in liver was significantly higher in Franciscana dolphin than estuarine dolphin, suggesting that demethylation ability of methyl Hg might be lower in liver of Franciscana than estuarine dolphins. High hepatic concentrations of Ag were found in some specimens of Franciscana dolphin (maximum, 20 {mu}g/g dry wt.), and 17% of Franciscana showed higher concentrations of Ag than Hg. These samples with high Ag concentration also exhibited elevated hepatic Se concentration, implying that Ag might be detoxified by Se in the liver. Higher correlation coefficient between (Hg + 0.5 Ag) and Se than between Hg and Se and the large distribution of Ag in non-soluble fraction in nuclear and mitochondrial fraction of the liver also suggests that Ag might be detoxified by Se via formation of Ag{sub 2}Se in the liver of Franciscana

Concentration and subcellular distribution of trace elements in liver of small cetaceans incidentally caught along the Brazilian coast

International Nuclear Information System (INIS)

Kunito, Takashi; Nakamura, Shinji; Ikemoto, Tokutaka; Anan, Yasumi; Kubota, Reiji; Tanabe, Shinsuke; Rosas, Fernando C.W.; Fillmann, Gilberto; Readman, James W.

2004-01-01

Concentrations of trace elements (V, Cr, Mn, Fe, Co, Cu, Zn, Ga, As, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, T-Hg, Org-Hg, Tl and Pb) were determined in liver samples of estuarine dolphin (Sotalia guianensis; n=20), Franciscana dolphin (Pontoporia blainvillei; n=23), Atlantic spotted dolphin (Stenella frontalis; n=2), common dolphin (Delphinus capensis; n=1) and striped dolphin (Stenella coeruleoalba; n=1) incidentally caught along the coast of Sao Paulo State and Parana State, Brazil, from 1997 to 1999. The hepatic concentrations of trace elements in the Brazilian cetaceans were comparable to the data available in literature on marine mammals from Northern Hemisphere. Concentrations of V, Se, Mo, Cd, T-Hg and Org-Hg increased with increasing age in liver of both estuarine and Franciscana dolphins. Very high concentrations of Cu (range, 262-1970 μg/g dry wt.) and Zn (range, 242-369 μg/g dry wt.) were observed in liver of sucklings of estuarine dolphin. Hepatic concentrations of V, Se, T-Hg, Org-Hg and Pb were significantly higher in estuarine dolphin, whereas Franciscana dolphin showed higher concentrations of Mn, Co, As and Rb. Ratio of Org-Hg to T-Hg in liver was significantly higher in Franciscana dolphin than estuarine dolphin, suggesting that demethylation ability of methyl Hg might be lower in liver of Franciscana than estuarine dolphins. High hepatic concentrations of Ag were found in some specimens of Franciscana dolphin (maximum, 20 μg/g dry wt.), and 17% of Franciscana showed higher concentrations of Ag than Hg. These samples with high Ag concentration also exhibited elevated hepatic Se concentration, implying that Ag might be detoxified by Se in the liver. Higher correlation coefficient between (Hg + 0.5 Ag) and Se than between Hg and Se and the large distribution of Ag in non-soluble fraction in nuclear and mitochondrial fraction of the liver also suggests that Ag might be detoxified by Se via formation of Ag 2 Se in the liver of Franciscana dolphin

Hepatitis B surface antigen (HBsAg) and core antigen (HBcAg) combine CpG oligodeoxynucletides as a novel therapeutic vaccine for chronic hepatitis B infection.

Science.gov (United States)

Li, Jianqiang; Ge, Jun; Ren, Sulin; Zhou, Tong; Sun, Ying; Sun, Honglin; Gu, Yue; Huang, Hongying; Xu, Zhenxing; Chen, Xiaoxiao; Xu, Xiaowei; Zhuang, Xiaoqian; Song, Cuiling; Jia, Fangmiao; Xu, Aiguo; Yin, Xiaojin; Du, Sean X

2015-08-20

Hepatitis B virus infection is a non-cytopathic hepatotropic virus which can lead to chronic liver disease and hepatocellular carcinoma. Traditional therapies fail to provide sustained control of viral replication and liver damage in most patients. As an alternative strategy, immunotherapeutic approaches have shown promising efficacy in the treatment of chronic hepatitis B patients. Here, we investigated the efficacy of a novel therapeutic vaccine formulation consisting of two HBV antigens, HBsAg and HBcAg, and CpG adjuvant. This vaccine formulation elicits forceful humoral responses directed against HBsAg/HBcAg, and promotes a Th1/Th2 balance response against HBsAg and a Th1-biased response against HBcAg in both C57BL/6 and HBV transgenic mice. Vigorous cellular immune response was also detected in HBV transgenic mice, for a significantly higher number of HBs/HBc-specific IFN-γ secreting CD4+ and CD8+ T cells was generated. Moreover, vaccinated mice elicited significantly intense in vivo CTL attack, reduced serum HBsAg level without causing liver damage in HBV transgenic mice. In summary, this study demonstrates a novel therapeutic vaccine with the potential to elicit vigorous humoral and cellular response, overcoming tolerance in HBV transgenic mice. Copyright © 2015 Elsevier Ltd. All rights reserved.

Limnological aspects and trace element analysis of some selected Kenyan natural inland waters

International Nuclear Information System (INIS)

Ochieng, E.O.

1987-01-01

This thesis reports the study of trace elements, Ag, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sn, and Zn, and some limnological factors in surface water and sediments in some selected natural inland waters in Kenya. The observed levels are compared with those that are reported in literature to cause interference in biological processes in aquatic environments and human beings. There are little previous data and none that are coherent. These allow for a preliminary assessment of the significance of each element and limnological parameters in the long term stability of the environments in which they occur. XRFA and AAs have been used in the trace elements analysis and the former proved superior in the sediment (solid) samples analysis due to better accuracy and precision of less than 10%. Trace metals concentration (ppb) in the surface inland waters (rivers and lakes ) ranged as follows: Ag (1-75), Cd (2-8), Co (6-23.2), Cr (25-50), Cu (5-57.6), Mn (50-3276±450), Ni (13-34.1), Pb (7-93.6), Sn (300-500) and Zn (25-124.8). Lake sediments had the following concentration (ppm) ranges: Ag (o.098-20.58), Cd (0.188-1.345), Co (0.166-1.632), Cr (1.462-57.310), Cu (1.949-44.350), Mn (667.670-4713), Ni (11.694-56.710), Pb (10.920-192), Sn 17.210-234) and Zn (76.210-229.60). Results show that, a part from the Rift Valley saline lakes, Kenya inland water meet the WHO (1971) drinking water standards related to aquatic living environments. Concentration of some trace metals: Ag, Cd, Cu, Mn and Zn change upon raw water treatments. Preconcentration techniques have been attempted in which preconcentration by evaporation followed by lyophilization of the liquid (water) samples was found more suitable. Bioavailable (total exchangeable) metal concentrations compared very well with the concentrations in the fish muscles. Comparison with the analysis made by earlier investigators indicated a remarkable constancy over time in the chemistry of Lake Victoria and its affluent rivers. Kenyan natural

The − 5 A/G single-nucleotide polymorphism in the core promoter region of MT2A and its effect on allele-specific gene expression and Cd, Zn and Cu levels in laryngeal cancer

Energy Technology Data Exchange (ETDEWEB)

Starska, Katarzyna, E-mail: katarzyna.starska@umed.lodz.pl [I Department of Otolaryngology and Laryngological Oncology, Medical University of Łódź, Kopcinskiego 22, 90-153 Łódź (Poland); Krześlak, Anna; Forma, Ewa [Department of Cytobiochemistry, University of Łódź, Pomorska 142/143, 90-236 Łódź (Poland); Olszewski, Jurek [II Department of Otolaryngology and Laryngological Oncology, Medical University of Łódź, Żeromskiego 113, 90-549 Łódź (Poland); Morawiec-Sztandera, Alina [Department of Head and Neck Surgery, Medical University of Łódź, Paderewskiego 4, 93-509 Łódź (Poland); Aleksandrowicz, Paweł [Department of Otolaryngology and Laryngological Oncology, Medical University of Lublin, Jaczewskiego 8, 20-954 Lublin (Poland); Lewy-Trenda, Iwona [Department of Pathology, Medical University of Łódź, Pomorska 251, 92-213 Łódź (Poland); and others

2014-10-15

Metallothioneins (MTs) are low molecular weight, cysteine-rich heavy metal-binding proteins which participate in the mechanisms of Zn homeostasis, and protect against toxic metals. MTs contain metal-thiolate cluster groups and suppress metal toxicity by binding to them. The aim of this study was to determine the − 5 A/G (rs28366003) single-nucleotide polymorphism (SNP) in the core promoter region of the MT2A gene and to investigate its effect on allele-specific gene expression and Cd, Zn and Cu content in squamous cell laryngeal cancer (SCC) and non-cancerous laryngeal mucosa (NCM) as a control. The MT2A promoter region − 5 A/G SNP was determined by restriction fragment length polymorphism using 323 SCC and 116 NCM. MT2A gene analysis was performed by quantitative real-time PCR. The frequency of A allele carriage was 94.2% and 91.8% in SCC and NCM, respectively, while G allele carriage was detected in 5.8% and 8.2% of SCC and NCM samples, respectively. As a result, a significant association was identified between the − 5 A/G SNP in the MT2A gene with mRNA expression in both groups. Metal levels were analyzed by flame atomic absorption spectrometry. The significant differences were identified between A/A and both the A/G and G/G genotypes, with regard to the concentration of the contaminating metal. The Spearman rank correlation results showed that the MT2A expression and Cd, Zn, Cu levels were negatively correlated. Results obtained in this study suggest that − 5 A/G SNP in MT2A gene may have an effect on allele-specific gene expression and accumulation of metal levels in laryngeal cancer. - Highlights: • MT2A gene expression and metal content in laryngeal cancer tissues • Association between SNP (rs28366003) and expression of MT2A • Significant associations between the SNP and Cd, Zn and Cu levels • Negative correlation between MT2A gene expression and Cd, Zn and Cu levels.

The − 5 A/G single-nucleotide polymorphism in the core promoter region of MT2A and its effect on allele-specific gene expression and Cd, Zn and Cu levels in laryngeal cancer

International Nuclear Information System (INIS)

Starska, Katarzyna; Krześlak, Anna; Forma, Ewa; Olszewski, Jurek; Morawiec-Sztandera, Alina; Aleksandrowicz, Paweł; Lewy-Trenda, Iwona

2014-01-01

Metallothioneins (MTs) are low molecular weight, cysteine-rich heavy metal-binding proteins which participate in the mechanisms of Zn homeostasis, and protect against toxic metals. MTs contain metal-thiolate cluster groups and suppress metal toxicity by binding to them. The aim of this study was to determine the − 5 A/G (rs28366003) single-nucleotide polymorphism (SNP) in the core promoter region of the MT2A gene and to investigate its effect on allele-specific gene expression and Cd, Zn and Cu content in squamous cell laryngeal cancer (SCC) and non-cancerous laryngeal mucosa (NCM) as a control. The MT2A promoter region − 5 A/G SNP was determined by restriction fragment length polymorphism using 323 SCC and 116 NCM. MT2A gene analysis was performed by quantitative real-time PCR. The frequency of A allele carriage was 94.2% and 91.8% in SCC and NCM, respectively, while G allele carriage was detected in 5.8% and 8.2% of SCC and NCM samples, respectively. As a result, a significant association was identified between the − 5 A/G SNP in the MT2A gene with mRNA expression in both groups. Metal levels were analyzed by flame atomic absorption spectrometry. The significant differences were identified between A/A and both the A/G and G/G genotypes, with regard to the concentration of the contaminating metal. The Spearman rank correlation results showed that the MT2A expression and Cd, Zn, Cu levels were negatively correlated. Results obtained in this study suggest that − 5 A/G SNP in MT2A gene may have an effect on allele-specific gene expression and accumulation of metal levels in laryngeal cancer. - Highlights: • MT2A gene expression and metal content in laryngeal cancer tissues • Association between SNP (rs28366003) and expression of MT2A • Significant associations between the SNP and Cd, Zn and Cu levels • Negative correlation between MT2A gene expression and Cd, Zn and Cu levels

Ag85-focused T-cell immune response controls Mycobacterium avium chronic infection.

Directory of Open Access Journals (Sweden)

Bruno Cerqueira-Rodrigues

Full Text Available CD4+ T cells are essential players for the control of mycobacterial infections. Several mycobacterial antigens have been identified for eliciting a relevant CD4+ T cell mediated-immune response, and numerous studies explored this issue in the context of Mycobacterium tuberculosis infection. Antigen 85 (Ag85, a highly conserved protein across Mycobacterium species, is secreted at the early phase of M. tuberculosis infection leading to the proliferation of Ag85-specific CD4+ T cells. However, in the context of Mycobacterium avium infection, little is known about the expression of this antigen and the elicited immune response. In the current work, we investigated if a T cell receptor (TCR repertoire mostly, but not exclusively, directed at Ag85 is sufficient to mount a protective immune response against M. avium. We show that P25 mice, whose majority of T cells express a transgenic TCR specific for Ag85, control M. avium infection at the same level as wild type (WT mice up to 20 weeks post-infection (wpi. During M. avium infection, Ag85 antigen is easily detected in the liver of 20 wpi mice by immunohistochemistry. In spite of the propensity of P25 CD4+ T cells to produce higher amounts of interferon-gamma (IFNγ upon ex vivo stimulation, no differences in serum IFNγ levels are detected in P25 compared to WT mice, nor enhanced immunopathology is detected in P25 mice. These results indicate that a T cell response dominated by Ag85-specific T cells is appropriate to control M. avium infection with no signs of immunopathology.

Increasing the ex vivo antigen-specific IFN-γ production in subpopulations of T cells and NKp46+ cells by anti-CD28, anti-CD49d and recombinant IL-12 costimulation in cattle vaccinated with recombinant proteins from Mycobacterium avium subspecies paratuberculosis

DEFF Research Database (Denmark)

Thakur, Aneesh; Riber, Ulla; Davis, William C.

2013-01-01

-γ secretion by CD4, CD8, γδ T cells and NK cells. Age matched male jersey calves, experimentally infected with Mycobacterium avium subsp. paratuberculosis (MAP), were vaccinated with a cocktail of recombinant MAP proteins or left unvaccinated. Vaccine induced ex vivo recall responses were measured through Ag......T cells, which encounter specific antigen (Ag), require additional signals to mount a functional immune response. Here, we demonstrate activation of signal 2, by anti-CD28 mAb (aCD28) and other costimulatory molecules (aCD49d, aCD5), and signal 3, by recombinant IL-12, enhance Ag-specific IFN...

Large-scale spatial and interspecies differences in trace elements and stable isotopes in marine wild fish from Chinese waters

Energy Technology Data Exchange (ETDEWEB)

Zhang, Wei [Key Laboratory of Marine Bio-resources Sustainable Utilization, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301 (China); Graduate School, Chinese Academy of Sciences, Beijing 100049 (China); Wang, Wen-Xiong, E-mail: wwang@ust.hk [Division of Life Science, HKUST, Clear Water Bay, Kowloon (Hong Kong)

2012-05-15

Highlights: Black-Right-Pointing-Pointer A large-scale study on trace element levels in marine wild fish from Chinese waters. Black-Right-Pointing-Pointer Spatial variation found for Al, As, Cd, Cr, Fe, Ni, Pb, but not for Ag, Cu, Mo, Se and Zn. Black-Right-Pointing-Pointer The Pearl River Estuary contained the highest concentrations of Al, Cr, Ni, and Pb. Black-Right-Pointing-Pointer No biomagnification occurred for any of the trace elements studied in marine fish. Black-Right-Pointing-Pointer No obvious health risk from the intake of trace elements through fish consumption. - Abstract: We conducted a large scale investigation of twelve trace element levels and stable isotopes ({delta}{sup 13}C and {delta}{sup 15}N) in twenty-nine marine wild fish species collected from Chinese coastal waters. Trace element levels varied significantly with species. Clear spatial variations were found for Al, As, Cd, Cr, Fe, Ni, and Pb, whereas Ag, Cu, Mo, Se and Zn did not show much spatial variation. The Pearl River Estuary contained the highest concentrations of Al, Cr, Ni, and Pb, whereas the most southern waters (Haikou) contained the lowest concentrations of Al, Fe, and Pb. There was no correlation between log-transformed trace elements concentrations and {delta}{sup 15}N values or {delta}{sup 13}C values, indicating no biomagnification among these trace elements. The calculated hazard quotients (HQ) of 10 elements were less than 1, thus there was no obvious health risk from the intake of trace elements through marine wild fish consumption.

High photocurrent gain in NiO thin film/M-doped ZnO nanorods (M=Ag, Cd and Ni) heterojunction based ultraviolet photodiodes

Energy Technology Data Exchange (ETDEWEB)

Echresh, Ahmad, E-mail: ahmadechresh@gmail.com [Department of Science and Technology, Physical Electronics and Nanotechnology Division, Campus Norrköping, Linköping University, SE-601 74 Norrköping (Sweden); Echresh, Mohammad [Department of Physics, Sanati Hoveizeh University, Ahvaz (Iran, Islamic Republic of); Khranovskyy, Volodymyr [Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-5818358183 Linköping (Sweden); Nur, Omer; Willander, Magnus [Department of Science and Technology, Physical Electronics and Nanotechnology Division, Campus Norrköping, Linköping University, SE-601 74 Norrköping (Sweden)

2016-10-15

The thermal evaporation method has been used to deposit p-type NiO thin film, which was combined with hydrothermally grown n-type pure and M-doped ZnO nanorods (M=Ag, Cd and Ni) to fabricate a high performance p-n heterojunction ultraviolet photodiodes. The fabricated photodiodes show high rectification ratio and relatively low leakage current. The p-NiO/n-Zn{sub 0.94}Ag{sub 0.06}O heterojunction photodiode displays the highest photocurrent gain (~1.52×10{sup 4}), a photoresponsivity of ~4.48×10{sup 3} AW{sup −1} and a photosensitivity of ~13.56 compared with the other fabricated photodiodes. The predominated transport mechanisms of the p-n heterojunction ultraviolet photodiodes at low and high applied forward bias may be recombination-tunneling and space charge limited current, respectively.

Ecto-ATPase CD39 Inactivates Isoprenoid-Derived Vγ9Vδ2 T Cell Phosphoantigens

Directory of Open Access Journals (Sweden)

Georg Gruenbacher

2016-07-01

Full Text Available In humans, Vγ9Vδ2 T cells respond to self and pathogen-associated, diphosphate-containing isoprenoids, also known as phosphoantigens (pAgs. However, activation and homeostasis of Vγ9Vδ2 T cells remain incompletely understood. Here, we show that pAgs induced expression of the ecto-ATPase CD39, which, however, not only hydrolyzed ATP but also abrogated the γδ T cell receptor (TCR agonistic activity of self and microbial pAgs (C5 to C15. Only mevalonate-derived geranylgeranyl diphosphate (GGPP, C20 resisted CD39-mediated hydrolysis and acted as a regulator of CD39 expression and activity. GGPP enhanced macrophage differentiation in response to the tissue stress cytokine interleukin-15. In addition, GGPP-imprinted macrophage-like cells displayed increased capacity to produce IL-1β as well as the chemokine CCL2 and preferentially activated CD161-expressing CD4+ T cells in an innate-like manner. Our studies reveal a previously unrecognized immunoregulatory function of CD39 and highlight a particular role of GGPP among pAgs.

Controllable synthesis of metal selenide heterostructures mediated by Ag2Se nanocrystals acting as catalysts

Science.gov (United States)

Zhou, Jiangcong; Huang, Feng; Xu, Ju; Wang, Yuansheng

2013-09-01

Ag2Se nanocrystals were demonstrated to be novel semiconductor mediators, or in other word catalysts, for the growth of semiconductor heterostructures in solution. This is a result of the unique feature of Ag2Se as a fast ion conductor, allowing foreign cations to dissolve and then to heterogrow the second phase. Using Ag2Se nanocrystals as catalysts, dimeric metal selenide heterostructures such as Ag2Se-CdSe and Ag2Se-ZnSe, and even multi-segment heterostructures such as Ag2Se-CdSe-ZnSe and Ag2Se-ZnSe-CdSe, were successfully synthesized. Several interesting features were found in the Ag2Se based heterogrowth. At the initial stage of heterogrowth, a layer of the second phase forms on the surface of an Ag2Se nanosphere, with a curved junction interface between the two phases. With further growth of the second phase, the Ag2Se nanosphere tends to flatten the junction surface by modifying its shape from sphere to hemisphere in order to minimize the conjunct area and thus the interfacial energy. Notably, the crystallographic relationship of the two phases in the heterostructure varies with the lattice parameters of the second phase, in order to reduce the lattice mismatch at the interface. Furthermore, a small lattice mismatch at the interface results in a straight rod-like second phase, while a large lattice mismatch would induce a tortuous product. The reported results may provide a new route for developing novel selenide semiconductor heterostructures which are potentially applicable in optoelectronic, biomedical, photovoltaic and catalytic fields.Ag2Se nanocrystals were demonstrated to be novel semiconductor mediators, or in other word catalysts, for the growth of semiconductor heterostructures in solution. This is a result of the unique feature of Ag2Se as a fast ion conductor, allowing foreign cations to dissolve and then to heterogrow the second phase. Using Ag2Se nanocrystals as catalysts, dimeric metal selenide heterostructures such as Ag2Se-CdSe and Ag2Se

TCRγδ+CD4−CD8− T Cells Suppress the CD8+ T-Cell Response to Hepatitis B Virus Peptides, and Are Associated with Viral Control in Chronic Hepatitis B

Science.gov (United States)

Lai, Qintao; Ma, Shiwu; Ge, Jun; Huang, Zuxiong; Huang, Xuan; Jiang, Xiaotao; Li, Yongyin; Zhang, Mingxia; Zhang, Xiaoyong; Sun, Jian; Abbott, William G. H.; Hou, Jinlin

2014-01-01

The immune mechanisms underlying failure to achieve hepatitis B e antigen (HBeAg) seroconversion associated with viral control in chronic hepatitis B (CHB) remain unclear. Here we investigated the role of CD4−CD8− T (double-negative T; DNT) cells including TCRαβ+ DNT (αβ DNT) and TCRγδ+ DNT (γδ DNT) cells. Frequencies of circulating DNT cell subsets were measured by flow cytometry in a retrospective cohort of 51 telbivudine-treated HBeAg-positive CHB patients, 25 immune tolerant carriers (IT), 33 inactive carriers (IC), and 37 healthy controls (HC). We found that γδ DNT cell frequencies did not significantly change during treatment, being lower at baseline (P = 0.019) in patients with HBeAg seroconversion after 52 weeks of antiviral therapy (n = 20) than in those without (n = 31), and higher in the total CHB and IT than IC and HC groups (P<0.001). αβ DNT cell frequencies were similar for all groups. In vitro, γδ DNT cells suppressed HBV core peptide-stimulated interferon-γ and tumor necrosis factor-α production in TCRαβ+CD8+ T cells, which may require cell–cell contact, and could be partially reversed by anti-NKG2A. These findings suggest that γδ DNT cells limit CD8+ T cell response to HBV, and may impede HBeAg seroconversion in CHB. PMID:24551107

The high-temperature modification of LuAgSn and high-pressure high-temperature experiments on DyAgSn, HoAgSn, and YbAgSn

Energy Technology Data Exchange (ETDEWEB)

Heying, B.; Rodewald, U.C.; Hermes, W.; Schappacher, F.M.; Riecken, J.F.; Poettgen, R. [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Heymann, G.; Huppertz, H. [Muenchen Univ. (Germany). Dept. fuer Chemie und Biochemie; Sebastian, C.P. [Max-Planck-Institut fuer Chemische Physik Fester Stoffe, Dresden (Germany)

2008-02-15

The high-temperature modification of LuAgSn was obtained by arc-melting an equiatomic mixture of the elements followed by quenching the melt on a water-cooled copper crucible. HT-LuAgSn crystallizes with the NdPtSb-type structure, space group P6{sub 3}mc: a = 463.5(1), c = 723.2(1) pm, wR2 = 0.0270, 151 F{sup 2}, and 11 variables. The silver and tin atoms build up two-dimensional, puckered [Ag{sub 3}Sn{sub 3}] networks (276 pm Ag-Sn) that are charge-balanced and separated by the lutetium atoms. The Ag-Sn distances between the [Ag{sub 3}Sn{sub 3}] layers of 294 pm are much longer. Single crystals of isotypic DyAgSn (a = 468.3(1), c = 734.4(1) pm, wR2 = 0.0343, 411 F{sup 2}, and 11 variables) and HoAgSn (a = 467.2(1), c = 731.7(2) pm, wR2 = 0.0318, 330 F{sup 2}, and 11 variables) were obtained from arc-melted samples. Under high-pressure (up to 12.2 GPa) and high-temperature (up to 1470 K) conditions, no transitions to a ZrNiAl-related phase have been observed for DyAgSn, HoAgSn, and YbAgSn. HT-TmAgSn shows Curie-Weiss paramagnetism with {mu}{sub eff} = 7.53(1) {mu}{sub B}/Tm atom and {theta}P = -15.0(5) K. No magnetic ordering was evident down to 3 K. HT-LuAgSn is a Pauli paramagnet. Room-temperature {sup 119}Sn Moessbauer spectra of HT-TmAgSn and HT-LuAgSn show singlet resonances with isomer shifts of 1.78(1) and 1.72(1) mm/s, respectively. (orig.)

Instrumental neutron activation analysis in environmental studies of trace elements

International Nuclear Information System (INIS)

Salmon, L.

1975-06-01

The application of a routine instrumental nuclear method is described in relation to environmental surveys and studies. A working rather than formal review is made of the techniques applied with particular reference to the data processing methods involved. The elements measured by instrumental activation analysis were: Ag, Al, As, Au, Ba, Br, Ca, Ce, Cl, Cd, Co, Cr, Cs, Cu, Fe, Hg, I, In, La, Mn, Na, Ni, Pb, Rb, Sb, Sc, Se, Th, Ti, U, V, W, Zn. (author)

Phosphine-free synthesis of high-quality reverse type-I ZnSe/CdSe core with CdS/Cd{sub x}Zn{sub 1-x}S/ZnS multishell nanocrystals and their application for detection of human hepatitis B surface antigen

Energy Technology Data Exchange (ETDEWEB)

Shen Huaibin; Niu Jin Zhong; Xu Shasha; Zhou Changhua; Li Linsong [Key Laboratory for Special Functional Materials, Henan University, Kaifeng 475004 (China); Yuan Hang; Ma Lan, E-mail: malan@sz.tsinghua.edu.cn, E-mail: lsli@henu.edu.cn [Life Science Division, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China)

2011-09-16

Highly photoluminescent (PL) reverse type-I ZnSe/CdSe nanocrystals (NCs) and ZnSe/CdSe/CdS/Cd{sub x}Zn{sub 1-x}S/ZnS core/multishell NCs were successfully synthesized by a phosphine-free method. By this low-cost, 'green' synthesis route, more than 10 g of high-quality ZnSe/CdSe/CdS/Cd{sub x}Zn{sub 1-x}S/ZnS NCs were synthesized in a large scale synthesis. After the overgrowth of a CdS/Cd{sub x}Zn{sub 1-x}S/ZnS multishell on ZnSe/CdSe cores, the PL quantum yields (QYs) increased from 28% to 75% along with the stability improvement. An amphiphilic oligomer was used as a surface coating agent to conduct a phase transfer experiment, core/multishell NCs were dissolved in water by such surface modification and the QYs were still kept above 70%. The as-prepared water dispersible ZnSe/CdSe/CdS/Cd{sub x}Zn{sub 1-x}S/ZnS core/multishell NCs not only have high fluorescence QYs but also are extremely stable in various physiological conditions. Furthermore, a biosensor system (lateral flow immunoassay system, LFIA) for the detection of human hepatitis B surface antigen (HBsAg) was developed by using this water-soluble core/multishell NCs as a fluorescent label and a nitrocellulose filter membrane for lateral flow. The result showed that such ZnSe/CdSe/CdS/Cd{sub x}Zn{sub 1-x}S/ZnS core/multishell NCs were excellent fluorescent labels to detect HBsAg. The sensitivity of HBsAg detection could reach as high as 0.05 ng ml{sup -1}.

Silver ion modulated CdS quantum dots for highly selective detection of trace Hg{sup 2+}

Energy Technology Data Exchange (ETDEWEB)

Uppa, Yuwapon; Kulchat, Sirinan; Ngamdee, Kessarin; Pradublai, Kaewklao [Materials Chemistry Research Unit, Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Tuntulani, Thawatchai [Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Ngeontae, Wittaya, E-mail: wittayange@kku.ac.th [Materials Chemistry Research Unit, Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Research Center for Environmental and Hazardous Substance Management, Khon Kaen University, Khon Kaen 40002 (Thailand); Center of Excellence for Environmental and Hazardous Waste Management (EHWM), Bangkok 10330 (Thailand)

2016-10-15

In the present work, water-soluble cysteamine capped-CdS quantum dots (Cys-CdS QDs) modulated with Ag{sup +} were employed as fluorescence sensors for the determination of Hg{sup 2+} ion. The synthesized Cys-CdS QDs exhibit relatively weak fluorescence emission, however, the emission was enhanced exclusively in the presence of Ag{sup +} compared to other metal ions. Moreover, the fluorescence intensity of the Ag{sup +} modulated Cys-CdS QDs (Ag{sup +}@Cys-CdS QDs) was significantly quenched in the presence of trace amounts of Hg{sup 2+} due to high-affinity metallophilic interactions between Hg{sup 2+} and Ag{sup +}. Based on this specific interaction, good selectivity towards the detection of Hg{sup 2+} over other metal ions was achieved. To gain the best sensing performance, parameters affecting the Hg{sup 2+} detection sensitivity were studied and optimized in detail. Under the optimized conditions, the fluorescence intensity of Ag{sup +}@Cys-CdS QDs decreased linearly with Hg{sup 2+} concentration in the range of 0.1–3.5 μM, with a limit of detection of around 0.09 μM. The applicability of this sensor was demonstrated by the determination of Hg{sup 2+} in drinking water samples, corresponding well with results of cold-vapor atomic absorption spectrometry.

Systemic immunological tolerance to ocular antigens is mediated by TNF-related apoptosis-inducing ligand (TRAIL)-expressing CD8+ T cells*

Science.gov (United States)

Griffith, Thomas S.; Brincks, Erik L.; Gurung, Prajwal; Kucaba, Tamara A.; Ferguson, Thomas A.

2010-01-01

Systemic immunological tolerance to Ag encountered in the eye restricts the formation of potentially damaging immune responses that would otherwise be initiated at other anatomical locations. We previously demonstrated that tolerance to Ag administered via the anterior chamber (AC) of the eye required FasL-mediated apoptotic death of inflammatory cells that enter the eye in response to the antigenic challenge. Moreover, the systemic tolerance induced after AC injection of Ag was mediated by CD8+ regulatory T cells. The present study examined the mechanism by which these CD8+ regulatory T cells mediate tolerance after AC injection of Ag. AC injection of Ag did not prime CD4+ T cells, and led to increased TRAIL expression by splenic CD8+ T cells. Unlike wildtype mice, Trail−/− or Dr5−/− mice did not develop tolerance to Ag injected into the eye, even though responding lymphocytes underwent apoptosis in the AC of the eyes of these mice. CD8+ T cells from Trail−/− mice that were first injected AC with Ag were unable to transfer tolerance to naïve recipient wildtype mice, but CD8+ T cells from AC-injected wildtype or Dr5−/− mice could transfer tolerance. Importantly, the transferred wildtype (Trail+/+) CD8+ T cells were also able to decrease the number of infiltrating inflammatory cells into the eye; however, Trail−/− CD8+ T cells were unable to limit the inflammatory cell ingress. Together, our data suggest that “helpless” CD8+ regulatory T cells generated after AC injection of Ag enforce systemic tolerance in a TRAIL-dependent manner to inhibit inflammation in the eye. PMID:21169546

Concentration of 17 Elements in Subcellular Fractions of Beef Heart Tissue Determined by Neutron Activation Analysis

Energy Technology Data Exchange (ETDEWEB)

Wester, P O

1964-12-15

Subcellular fractions of beef heart tissue are investigated, by means of neutron activation analysis, with respect to their concentration of 17 different elements. A recently developed ion-exchange technique combined with gamma spectrometry is used. The homogeneity of the subcellular fractions is examined electron microscopically. The following elements are determined: As, Ba, Br, Cas Co, Cs, Cu, Fe, Hg, La, Mo, P, Rb, Se, Sm, W and Zn. The determination of Ag, Au, Cd, Ce, Cr, Sb and Sc is omitted, in view of contamination. Reproducible and characteristic patterns of distribution are obtained for all elements studied.

Concentration of 17 Elements in Subcellular Fractions of Beef Heart Tissue Determined by Neutron Activation Analysis

International Nuclear Information System (INIS)

Wester, P.O.

1964-12-01

Subcellular fractions of beef heart tissue are investigated, by means of neutron activation analysis, with respect to their concentration of 17 different elements. A recently developed ion-exchange technique combined with gamma spectrometry is used. The homogeneity of the subcellular fractions is examined electron microscopically. The following elements are determined: As, Ba, Br, Cas Co, Cs, Cu, Fe, Hg, La, Mo, P, Rb, Se, Sm, W and Zn. The determination of Ag, Au, Cd, Ce, Cr, Sb and Sc is omitted, in view of contamination. Reproducible and characteristic patterns of distribution are obtained for all elements studied

Study of Cd Te recrystallization by hydrated-CdCl_2 thermal treatment

International Nuclear Information System (INIS)

Hernandez V, C.; Albor A, M. L.; Galarza G, U.; Aguilar H, J. R.; Gonzalez T, M. A.; Flores M, J. M.; Jimenez O, D.

2017-01-01

Cd Te thin films solar cells are currently produced using a layer sequence of glass/FTO/CdS/Cd Te/metal contact (Cu/Ag), these films are deposited by two different techniques, chemical bath deposition (CBD) and close space vapour transport (CSVT). In order to reach reasonable conversion efficiencies, the device has to be thermally treated in a hydrated-CdCl_2 atmosphere. This study was carried out using X-ray diffraction (XRD), photoluminescence, Sem-EDS, four probe method and Sims profiling of Cd Te. These analyses confirm the presence of hydrated CdCl_2 and Cd Te phases on Cd Te surface and shown a good recrystallization morphology helping to the carriers mobility along the structure. Using the thermal treatment was possible to reduce the resistivity of Cd Te thin film; it is a result to the Cl migration along the Cd Te solar cell structure, reducing the defects between CdS and Cd Te thin films. A strong Cd Te thin film recrystallization was observed by the implementation of a hydrated-CdCl_2 treatment doing to this a good candidate to Cd Te solar cells process. (Author)

Stable isotope and trace element status of subsistence-hunted bowhead and beluga whales in Alaska and gray whales in Chukotka

Energy Technology Data Exchange (ETDEWEB)

Dehn, Larissa-A. [Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775-7000 (United States)]. E-mail: ftld@uaf.edu; Follmann, Erich H. [Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775-7000 (United States); Rosa, Cheryl [Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775-7000 (United States); Duffy, Lawrence K. [Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775-7000 (United States); Thomas, Dana L. [Department of Mathematical Sciences, University of Alaska Fairbanks, Fairbanks, AK 99775-6660 (United States); Bratton, Gerald R. [Department of Veterinary Anatomy and Public Health, Texas A and M University, College Station, TX 77843 (United States); Taylor, Robert J. [Department of Veterinary Anatomy and Public Health, Texas A and M University, College Station, TX 77843 (United States); O' Hara, Todd M. [Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775-7000 (United States); Department of Wildlife Management, North Slope Borough, Barrow, AK 99725 (United States)

2006-03-15

Tissues of bowhead, beluga, and gray whales were analyzed for Ag, Cd, Cu, Se, Zn, THg and MeHg (belugas only). {delta}{sup 15}N and {delta}{sup 13}C in muscle were used to estimate trophic position and feeding habitat, respectively. Trace element concentrations in tissues were significantly different among whale species. Hepatic Ag was higher in belugas than bowheads and gray whales. Gray whales had lower Cd concentrations in liver and kidney than bowhead and belugas and a sigmoid correlation of Cd with length was noted for all whales. Renal and hepatic Se and THg were higher in belugas than in baleen whales. The hepatic molar ratio of Se:THg exceeded 1:1 in all species and was negatively correlated to body length. Hepatic and renal Zn in subsistence-harvested gray whales was lower than concentrations for stranded whales. Se:THg molar ratios and tissue concentrations of Zn may show promise as potential indicators of immune status and animal health.

Stable isotope and trace element status of subsistence-hunted bowhead and beluga whales in Alaska and gray whales in Chukotka

International Nuclear Information System (INIS)

Dehn, Larissa-A.; Follmann, Erich H.; Rosa, Cheryl; Duffy, Lawrence K.; Thomas, Dana L.; Bratton, Gerald R.; Taylor, Robert J.; O'Hara, Todd M.

2006-01-01

Tissues of bowhead, beluga, and gray whales were analyzed for Ag, Cd, Cu, Se, Zn, THg and MeHg (belugas only). δ 15 N and δ 13 C in muscle were used to estimate trophic position and feeding habitat, respectively. Trace element concentrations in tissues were significantly different among whale species. Hepatic Ag was higher in belugas than bowheads and gray whales. Gray whales had lower Cd concentrations in liver and kidney than bowhead and belugas and a sigmoid correlation of Cd with length was noted for all whales. Renal and hepatic Se and THg were higher in belugas than in baleen whales. The hepatic molar ratio of Se:THg exceeded 1:1 in all species and was negatively correlated to body length. Hepatic and renal Zn in subsistence-harvested gray whales was lower than concentrations for stranded whales. Se:THg molar ratios and tissue concentrations of Zn may show promise as potential indicators of immune status and animal health

Transport, fate, and stimulating impact of silver nanoparticles on the removal of Cd(II) by Phanerochaete chrysosporium in aqueous solutions

International Nuclear Information System (INIS)

Zuo, Yanan; Chen, Guiqiu; Zeng, Guangming; Li, Zhongwu; Yan, Ming; Chen, Anwei; Guo, Zhi; Huang, Zhenzhen; Tan, Qiong

2015-01-01

Highlights: • Appropriate concentration of AgNPs can stimulate the biological removal of Cd(II). • Added AgNPs were oxidatively dissolved and transported to the surface of fungus. • AgNPs have undergone coarsening in the process of transport. • Amino, carboxyl, hydroxyl, and other reducing groups were involved in transportion. - Abstract: Despite the knowledge about increasing discharge of silver nanoparticles (AgNPs) into wastewater and its potential toxicity to microorganisms, the interaction of AgNPs with heavy metals in the biological removal process remains poorly understood. This study focused on the effect of AgNPs (hydrodynamic diameter about 24.3 ± 0.37 nm) on the removal of cadmium (Cd(II)) by using a model white rot fungus species, Phanerochaete chrysosporium. Results showed that the biological removal capacity of Cd(II) increased with the concentration of AgNPs increasing from 0.1 mg/L to 1 mg/L. The maximum removal capacity (4.67 mg/g) was located at 1 mg/L AgNPs, and then decreased with further increasing AgNPs concentration, suggesting that an appropriate concentration of AgNPs has a stimulating effect on the removal of Cd(II) by P. chrysosporium instead of an inhibitory effect. Results of Ag + and total Ag concentrations in the solutions together with those of SEM and XRD demonstrated that added AgNPs had undergone oxidative dissolution and transported from the solution to the surface of fungal mycelia (up to 94%). FTIR spectra confirmed that amino, carboxyl, hydroxyl, and other reducing functional groups were involved in Cd(II) removal, AgNPs transportation, and the reduction of Ag + to AgNPs

Transport, fate, and stimulating impact of silver nanoparticles on the removal of Cd(II) by Phanerochaete chrysosporium in aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Zuo, Yanan [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Chen, Guiqiu, E-mail: gqchen@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Zeng, Guangming, E-mail: zgming@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Li, Zhongwu; Yan, Ming [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Chen, Anwei [College of Resources and Environment, Hunan Agricultural University, Changsha 410128 (China); Guo, Zhi; Huang, Zhenzhen; Tan, Qiong [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China)

2015-03-21

Highlights: • Appropriate concentration of AgNPs can stimulate the biological removal of Cd(II). • Added AgNPs were oxidatively dissolved and transported to the surface of fungus. • AgNPs have undergone coarsening in the process of transport. • Amino, carboxyl, hydroxyl, and other reducing groups were involved in transportion. - Abstract: Despite the knowledge about increasing discharge of silver nanoparticles (AgNPs) into wastewater and its potential toxicity to microorganisms, the interaction of AgNPs with heavy metals in the biological removal process remains poorly understood. This study focused on the effect of AgNPs (hydrodynamic diameter about 24.3 ± 0.37 nm) on the removal of cadmium (Cd(II)) by using a model white rot fungus species, Phanerochaete chrysosporium. Results showed that the biological removal capacity of Cd(II) increased with the concentration of AgNPs increasing from 0.1 mg/L to 1 mg/L. The maximum removal capacity (4.67 mg/g) was located at 1 mg/L AgNPs, and then decreased with further increasing AgNPs concentration, suggesting that an appropriate concentration of AgNPs has a stimulating effect on the removal of Cd(II) by P. chrysosporium instead of an inhibitory effect. Results of Ag{sup +} and total Ag concentrations in the solutions together with those of SEM and XRD demonstrated that added AgNPs had undergone oxidative dissolution and transported from the solution to the surface of fungal mycelia (up to 94%). FTIR spectra confirmed that amino, carboxyl, hydroxyl, and other reducing functional groups were involved in Cd(II) removal, AgNPs transportation, and the reduction of Ag{sup +} to AgNPs.

Effects of industrial by-product amendments on As, Cd and Tl retention/release in an element-spiked acidic soil

International Nuclear Information System (INIS)

Aguilar-Carrillo, Javier; Barrios, Laura; Garrido, Fernando; Garcia-Gonzalez, Maria Teresa

2007-01-01

To asses the efficiency of two by-products (phosphogypsum (PG) and sugar foam (SF), rich in gypsum and calcium carbonate, respectively) in the immobilization of three toxic elements (As, Cd and Tl) in an acidic soil, batch-scale sorption and desorption experiments were conducted after 18 months of in situ amendment application. The Langmuir isotherms applied for sorption studies showed that the estimated maximum sorption capacity of the elements was highest in the SF-treated samples. The amount of element retained and the percentage of extraction after TCLP tests indicated that those samples amended with sugar foam (SF and PG + SF) had the potential to immobilize As, Cd and Tl in an acidic soil with low sorptive capacity. In addition to sorption and desorption experiments, scanning electron microscopy in back-scattered electron mode (SEM-BSE) showed the formation of Al-hydroxy polymers which provides the soil with additional sorption capacity. The three target elements were associated with the Al-hydroxy polymers, probably through direct coordination or the formation of ternary complexes. By means of statistical analysis it has been found that sorption processes of As, Cd and Tl in this soil mainly depend on the treatment, whereas desorption is an element-dependent process

The behaviour of the elements Ni, Co, Cu, Pb, Zn, Au, Ag, Mo, Sn, W and U in the magmatic, hydrothermal, sedimentary and weathering environments

International Nuclear Information System (INIS)

Anderson, J.R.

1978-01-01

In the last two decades much has been published on the behaviour of certain elements in the magmatic, hydrothermal, sedimentary and weathering environments, but the information is scattered throughout the literature. This situation prompted the present study on the elements Ni, Co, Cu, Pb, Zn, Au, Ag, Mo, Sn, W and U. The behaviour of the elements Ni, Cu, Pb, Zn, Au, Sn, W and U has been studied experimentally in some depth. Ag has been moderately studied, but there is very little information about Co and Mo. Studies on the complexes formed by the elements within the hydrothermal and aqueous environment are often inconclusive and controversial, but conclusions are drawn as to the more likely complexes formed. A genetic classification of ore deposits is used as a framework for the discussion. The source of the elements is regarded as being the mantle, and therefore discussion on other possible sources is beyond the scope of this dissertation. The crystal chemistry and geochemistry of the elements are presented and the essay concludes with a discussion on the elements within their depositional environments

Micro-PIXE study of Ag in digestive glands of a nano-Ag fed arthropod (Porcellio scaber, Isopoda, Crustacea)

International Nuclear Information System (INIS)

Tkalec, Ziva Pipan; Drobne, Damjana; Vogel-Mikus, Katarina; Pongrac, Paula; Regvar, Marjana; Strus, Jasna; Pelicon, Primoz; Vavpetic, Primoz; Grlj, Natasa; Remskar, Maja

2011-01-01

Micro-proton induced X-ray emission (micro-PIXE) method was applied to study the micro-localization of silver (Ag) in digestive glands of a terrestrial arthropod (Porcellio scaber) after feeding on silver nanoparticles (nano-Ag) dosed food. The aim of our work was to assess whether feeding on nano-Ag results in the assimilation of silver (Ag) in digestive gland cells. To study micro-localization and elemental distribution of Ag, the animals were fed on food dosed with nanoparticles for 14 days under controlled laboratory conditions. At the end of the feeding exposure, the animals were dissected and digestive glands prepared for micro-PIXE analyses and TEM investigation. The results obtained by micro-PIXE documented high amounts of Ag inside S-cells of the digestive gland epithelium; however, TEM investigation did not show particle aggregates inside digestive gland cells. Also no adverse effect on feeding behavior was recorded what is a measure of toxic effects. We explain the presence of Ag inside the cells as a result of the assimilation of dissoluted Ag ions from ingested nano-Ag particles. Assimilation of excessive amounts of ingested metal ions in S-cells is a well known metal detoxification mechanism in isopods. We discuss the advantages of using micro-PIXE for the micro-localization of elements in biological tissue in studies of interactions between nanoparticles and biological systems.

A method for the quantitative analysis of heavy elements by X-ray fluorescence

International Nuclear Information System (INIS)

Souza Caillaux, Z. de

1981-01-01

A study of quantitative analysis methodology by X-ray fluorescence analysis is presented. With no damage to precision it makes possible an analysis of heavy elements in samples with the form and texture as they present themselves. Some binary alloys were examined such as: FeCo; CuNi; CuZn; AgCd; AgPd; AuPt e PtIr. The possibility of application of this method is based on the compromise solutIon of wave lengths and the intensity of the homologous emission and absorption edges of constituents with the quantic efficiency of the detector, the dispersion and the wave lenght resolution of crystal analyser, and the uniformity of the excitation intensity. (Author) [pt

Nickel-like spectra of elements Y XII to Ag XX from a vacuum spark

International Nuclear Information System (INIS)

Schweitzer, N.; Klapisch, M.; Schwob, J.L.; Finkenthal, M.; Bar-Shalom, A.; Mandelbaum, P.

1980-05-01

The spectra of elements Y, Zr, Nb, Mo, Ru, Rh, Pd and Ag in the range 10-100 A were obtained from a high power vacuum spark and a grazing incidence high resolution spectrograph. The transitions 3d 10 -3d 9 4p, -3d 9 4f, 3d 9 5p, -3d 9 5f were identified. The agreement with ab initio relativistic calculations is very good. The relevance of jj coupling scheme for level labeling is discussed, as well as the importance of relativistic effects, by comparing with other results on high Z atoms (up to Pt)

Study of Cd Te recrystallization by hydrated-CdCl{sub 2} thermal treatment

Energy Technology Data Exchange (ETDEWEB)

Hernandez V, C.; Albor A, M. L.; Galarza G, U.; Aguilar H, J. R. [IPN, Escuela Superior de Fisica y Matematicas, Departamento de Fisica, San Pedro Zacatenco, 07738 Ciudad de Mexico (Mexico); Gonzalez T, M. A. [IPN, Escuela Superior de Computo, Nueva Industrial Vallejo, 07738 Ciudad de Mexico (Mexico); Flores M, J. M. [IPN, Escuela Superior de Ingenieria Quimica e Industrias Extractivas, Departamento de Ingenieria en Metalurgia y Materiales, Nueva Industrial Vallejo, 07738 Ciudad de Mexico (Mexico); Jimenez O, D. [IPN, Escuela Superior de Ingenieria Mecanica y Electrica, SEPI, Nueva Industrial Vallejo, 07738 Ciudad de Mexico (Mexico)

2017-11-01

Cd Te thin films solar cells are currently produced using a layer sequence of glass/FTO/CdS/Cd Te/metal contact (Cu/Ag), these films are deposited by two different techniques, chemical bath deposition (CBD) and close space vapour transport (CSVT). In order to reach reasonable conversion efficiencies, the device has to be thermally treated in a hydrated-CdCl{sub 2} atmosphere. This study was carried out using X-ray diffraction (XRD), photoluminescence, Sem-EDS, four probe method and Sims profiling of Cd Te. These analyses confirm the presence of hydrated CdCl{sub 2} and Cd Te phases on Cd Te surface and shown a good recrystallization morphology helping to the carriers mobility along the structure. Using the thermal treatment was possible to reduce the resistivity of Cd Te thin film; it is a result to the Cl migration along the Cd Te solar cell structure, reducing the defects between CdS and Cd Te thin films. A strong Cd Te thin film recrystallization was observed by the implementation of a hydrated-CdCl{sub 2} treatment doing to this a good candidate to Cd Te solar cells process. (Author)

Role of polymer matrix on photo-sensitivity of CdSe polymer nanocomposites

Science.gov (United States)

Kaur, Ramneek; Tripathi, S. K.

2018-04-01

This paper reports the effect of three different polymer matrices (PVP, PMMA and PVK) and Ag doping on the photo-sensitivity of CdSe polymer nanocomposites. The results reveal that the photoconductivity is high for linear chain polymer nanocomposites as compared to aromatic ones with decreasing trend as: CdSe-PMMA > CdSe-PVP > CdSe-PVK. The large substituents or branches along the polymer backbone hinder the stacking sequences in CdSe-PVK nanocomposites resulting in lowest photoconductivity. On contrary, CdSe-PVK nanocomposite exhibit highest photosensitivity. The reason behind it is the low value of dark conductivity in CdSe-PVK nanocomposite and photoconductive PVK matrix. With Ag doping, no considerable effect on the value of photosensitivity has been observed. The obtained results indicate that the photo-conducting properties of these polymer nanocomposites can be tuned by using different polymer matrices.

Volatile and siderophile trace elements in anorthositic rocks from Fiskenaesset, West Greenland: comparison with lunar and meteoritic analogues

International Nuclear Information System (INIS)

Morgan, J.W.; Ganapathy, R.; Higuchi, H.; Kraehenbuehl, U.

1976-01-01

Seventeen trace elements (Ag, Au, Bi, Br, Cd, Cs, Ge, Ir, Ni, Rb, Re, Sb, Se, Te, Tl, U, Zn) were analysed by radiochemical neutron activation and 13 other elements (Ce, Co, Cr, Eu, Fe, Hf, La, Lu, Na, Sc, Sm, Tb, Yb) by instrumental neutron activation in a total of 12 rocks from the layered anorthositic complex at Fiskenaesset, West Greenland, and in the plagioclase-rich unbrecciated eucrite, Serra de Mage. The results are discussed and compared with lunar and meteoritic analogues. (author)

Association Between Promoter Polymorphisms in CD46 and CD59 in Kidney Donors and Transplant Outcome

Directory of Open Access Journals (Sweden)

Laura A. Michielsen

2018-05-01

Full Text Available Complement regulating proteins, including CD46, CD55, and CD59, protect cells against self-damage. Because of their expression on the donor endothelium, they are hypothesized to be involved in accommodation. Polymorphisms in their promoter regions may affect their expression. The aim of this study was to investigate if donor polymorphisms in complement regulating proteins influence kidney transplant outcomes. We included 306 kidney transplantations between 2005 and 2010. Five polymorphisms in the promoters of CD46, CD55, and CD59 were genotyped. A CD59 promoter polymorphism (rs147788946 in donors was associated with a lower 1-year rejection-free survival [adjusted hazard ratio (aHR 2.18, 95% CI 1.12–4.24] and a trend toward impaired 5-year graft survival (p = 0.08. Patients receiving a kidney with at least one G allele for the CD46 promoter polymorphism rs2796267 (A/G showed a lower rejection-free survival, though this became borderline significant after adjustment for potential confounders (aHR 1.87, 95% CI 0.96–3.65. A second CD46 promoter polymorphism (rs2796268, A/G, was also associated with a lower freedom from acute rejection in the presence of at least one G allele (aHR 1.95, 95% CI 1.03–3.68. Finally, the combined presence of both favorable genotypes of rs2796267 and rs147788946 had an additional protective effect both on acute rejection (p = 0.006 and graft survival (p = 0.03. These findings could help to identify patients who could benefit from intensified immunosuppressive therapy or novel complement inhibitory therapeutics.

Solid phase extraction of trace amounts of Ag, Cd, Cu, and Zn in environmental samples using magnetic nanoparticles coated by 3-(trimethoxysilyl)-1-propantiol and modified with 2-amino-5-mercapto-1,3,4-thiadiazole and their determination by ICP-OES

International Nuclear Information System (INIS)

Mashhadizadeh, Mohammad Hossein; Karami, Zahra

2011-01-01

Highlights: → The enrichment factors in this method are better than the other reported methods. → The proposed method showed a very good sensitivity and high enrichment factor. → This adsorbent was prepared easily, utilized conveniently and harmless to environment. → This method is suitable for preconcentration of heavy metals in environmental samples. - Abstract: A fast, sensitive, and simple method using magnetic nanoparticles (MNPs) coated by 3-(trimethoxysilyl)-1-propantiol and modified with 2-amino-5-mercapto-1,3,4-thiadiazole, as an adsorbent has been successfully developed for extraction, preconcentration, and determination of trace amounts of Ag, Cd, Cu, and Zn from environmental samples. The prepared nanoparticles were characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). These magnetic nanoparticles can be easily dispersed in aqueous samples and retrieved by the application of external magnetic field via a piece of permanent magnet. The main factors affecting the extraction efficiency such as pH value, sample volume, eluent concentration and volume, ultrasonication time, and coexisting ions have been investigated and established. Under the optimal conditions, high concentration factors (194, 190, 170, and 182) were achieved for Ag, Cd, Cu, and Zn with relative standard deviations of 5.31%, 4.03%, 3.62%, and 4.20%, respectively. The limits of detection for Ag, Cd, Cu, and Zn were as low as 0.12, 0.12, 0.13 and 0.11 ng mL -1 . The prepared sorbent was applied for preconcentration of trace amounts of Ag, Cd, Cu, and Zn in the various water samples with satisfactory results.

Trace Elements in the Conductive Tissue of Beef Heart Determined by Neutron Activation Analysis

Energy Technology Data Exchange (ETDEWEB)

Wester, P O

1965-08-15

By means of neutron activation analysis, samples of four beef hearts taken from the bundle of His and adjacent ventricular muscle, the AV node and adjacent atrial muscle are investigated with respect to the concentration of 23 trace elements. The bulk elements K, Na and P are also determined. A recently developed ion-exchange technique, combined with subsequent {gamma}-spectrometry, is used. The following trace elements are determined: Ag, As, Au, Ba, Br, .Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Hg, La, Mo, Rb, Sb, Sc, Se, Sm, W and Zn. In the conductive tissue compared to adjacent muscle tissue, calculations on a wet weight basis show a lower concentration of Cs, Cu, Fe, K, P, Rb and Zn in the former, and a higher concentration of Ag, Au, Br, Ca and Na. The mean differences ({mu}g/g wet tissue), as well as their degree of significance, between the bundle of His and adjacent tissue from the ventricular septum, between the AV node and adjacent atrial muscle, between the ventricular septum and the right atrium, and between the bundle of His and the AV node are given for the elements Cu, Fe, K, Na, P and Zn.

Trace Elements in the Conductive Tissue of Beef Heart Determined by Neutron Activation Analysis

International Nuclear Information System (INIS)

Wester, P.O.

1965-08-01

By means of neutron activation analysis, samples of four beef hearts taken from the bundle of His and adjacent ventricular muscle, the AV node and adjacent atrial muscle are investigated with respect to the concentration of 23 trace elements. The bulk elements K, Na and P are also determined. A recently developed ion-exchange technique, combined with subsequent γ-spectrometry, is used. The following trace elements are determined: Ag, As, Au, Ba, Br, .Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Hg, La, Mo, Rb, Sb, Sc, Se, Sm, W and Zn. In the conductive tissue compared to adjacent muscle tissue, calculations on a wet weight basis show a lower concentration of Cs, Cu, Fe, K, P, Rb and Zn in the former, and a higher concentration of Ag, Au, Br, Ca and Na. The mean differences (μg/g wet tissue), as well as their degree of significance, between the bundle of His and adjacent tissue from the ventricular septum, between the AV node and adjacent atrial muscle, between the ventricular septum and the right atrium, and between the bundle of His and the AV node are given for the elements Cu, Fe, K, Na, P and Zn

Cu(I), Ag(I), Cd(II), and Pb(II) binding to biomolecules studied by perturbed angular correlation of $\\gamma$-rays (PAC) spectroscopy

CERN Multimedia

Metal ions display diverse functions in biological systems and are essential components in both protein and nucleic acid structure and function, and in control of biochemical reaction paths and signalling. Similarly, metal ions may be used to control structure and function of synthetic biomolecules, and thus be a tool in the design of molecules with a desired function. In this project we address a variety of questions concerning both the function of metal ions in natural systems, in synthetic biomolecules, and the toxic effect of some metal ions. All projects involve other experimental techniques such as NMR, EXAFS, UV-Vis, fluorescence, and CD spectroscopies providing complementary data, as well as interpretation of the experimental data by quantum mechanical calculations of spectroscopic properties. The isotopes to be employed in the proposal are the following: $^{111m}$Cd, $^{111}$Ag, $^{199m}$Hg, $^{204m}$Pb, $^{61}$Cu, $^{68m}$Cu

Microscopic theory of cation exchange in CdSe nanocrystals.

Science.gov (United States)

Ott, Florian D; Spiegel, Leo L; Norris, David J; Erwin, Steven C

2014-10-10

Although poorly understood, cation-exchange reactions are increasingly used to dope or transform colloidal semiconductor nanocrystals (quantum dots). We use density-functional theory and kinetic Monte Carlo simulations to develop a microscopic theory that explains structural, optical, and electronic changes observed experimentally in Ag-cation-exchanged CdSe nanocrystals. We find that Coulomb interactions, both between ionized impurities and with the polarized nanocrystal surface, play a key role in cation exchange. Our theory also resolves several experimental puzzles related to photoluminescence and electrical behavior in CdSe nanocrystals doped with Ag.

Exchangeable fraction of elements in alluvial sediments under waste disposal site (Zagreb, Croatia)

International Nuclear Information System (INIS)

Vertacnik, A.; Barisic, D.; Musani, Lj.; Prohic, E.; Juracic, M.

1997-01-01

Concentrations of Ag, Ba, Cd, Ce, Cs, Co, Cr, Eu, Fe, Rb, Sc, Sr, Th, and Zn exchangeable fractions were determined in alluvial sediments at waste disposal site area in the vicinity of water-well field. Samples have been'leached with 0.5M NH 4 Cl at a sample/solution ratio of 1:20 during 24 hours without shaking. INAA of dry NH 4 Cl residues show that the concentrations of exchangeable elements determined in the most of the sediments below the wastes have natural levels. Ag, Ba and Sr are readily exchangeable; Rb, Cs and Zn have lower exchangeability, while Cd, Ce, Th, Sc, Eu, Cr, Fe and Co are rather immobile. Extremely high total and exchangeable silver concentration was found at 6.5-6.8 meters below waste in the aerated layer occasionally under the water table. Exchangeable concentrations in deeper water-bearing sediment layers are not elevated. Due to this, one can presume that the upper sediment layers act as chemical filter generally preventing the infiltration from overlying wastes into water-bearing layers. (author)

Leukocyte function-associated antigen-1-dependent lysis of Fas+ (CD95+/Apo-1+) innocent bystanders by antigen-specific CD8+ CTL.

Science.gov (United States)

Kojima, H; Eshima, K; Takayama, H; Sitkovsky, M V

1997-09-15

Exquisite specificity toward Ag-bearing cells (cognate targets) is one of the most important properties of CD8+ CTL-mediated cytotoxicity. Using highly Ag-specific CD8+ CTL lines and clones, which spare noncognate, Ag-free targets, we found that in the presence of Ag-bearing targets the CTL acquire the ability to lyse noncognate target cells (bystanders). It is shown that the unexpectedly rapid and efficient lysis of bystanders by Ag-activated CTL is mediated by a Fas ligand (FasL)/Fas-based mechanism and does not depend on perforin. The CTL lysed Fas-expressing bystanders, but spared the Fas-negative or anti-Fas mAb-resistant bystander cells. Accordingly, the FasL-deficient gld/gld CTL did not kill bystanders, while perforin-deficient CTL did. Unlike anti-Fas mAb-induced cell death, the lysis of bystanders was not only FasL/Fas dependent but also required adhesion molecule LFA-1 on the surface of the activated CTL. Lysis of bystanders is viewed as acceptable "collateral" damage, but the persistent presence of activated CTL could result in immunopathologies involving functional Fas-expressing tissues.

Composition of the earth's upper mantle. II - Volatile trace elements in ultramafic xenoliths

Science.gov (United States)

Morgan, J. W.; Wandless, G. A.; Petrie, R. K.; Irving, A. J.

1980-01-01

Radiochemical neutron activation analysis was used to determine the nine volatile elements Ag, Bi, Cd, In, Sb, Se, Te, Tl, and Zn in 19 ultramafic rocks, consisting mainly of spinel and garnet lherzolites. A sheared garnet lherzolite, PHN 1611, may approximate undepleted mantle material and tends to have a higher volatile element content than the depleted mantle material represented by spinel lherzolites. Comparisons of continental basalts with PHN 1611 and of oceanic ridge basalts with spinel lherzolites show similar basalt: source material partition factors for eight of the nine volatile elements, Sb being the exception. The strong depletion of Te and Se in the mantle, relative to lithophile elements of similar volatility, suggests that 97% of the earth's S, Se and Te may be in the outer core.

Influence of Temperature on the Formation of Ag Complexed in a S2O32−–O2 System

Directory of Open Access Journals (Sweden)

Aislinn M. Teja-Ruiz

2017-01-01

Full Text Available Metallic elements of higher economic value, occurring in the mineralogy of Zimapán, are Pb, Zn, Cu, and Fe; said elements are sold as concentrates, which, even after processing, generally include significant concentrations of Mo, Cd, Sb, Ag, and As that can be recovered through different leaching methods. In this work, the influence of temperature in the complexation of silver contained in a concentrate of Zn using the technology of thiosulfate with oxygen injection was studied. Chemical and mineralogical characterization of the mineral concentrate from the state of Hidalgo, Mexico confirmed the existence of silver contained in a sulfide of silver arsenic (AgAsS2 by X-ray Diffraction (XRD. The results obtained by Atomic Absorption Spectrophotometry (AAS reported abundant metallic contents (% w/w (48% Zn, 10.63% Fe, 1.97% Cu, 0.84% Pb, 0.78% As, and 0.25% Ag. These results corroborate the presence of metallic sulfides such as pyrite, chalcopyrite, and wurtzite; this last species was identified as the matrix of the concentrate by X-ray Diffraction (XRD and Scanning Electron Microscopy-Energy-Dispersive X-ray Spectroscopy (SEM-EDS. Pourbaix diagrams were constructed for the AgAsS2–S2O32−–O2 system at different temperatures, which allowed the chemical reaction of leaching to be established, in addition to determining Eh-pH conditions in which to obtain silver in solution. The highest recoveries of the precious metal (97% Ag were obtained at a temperature of 333 K and [S2O32−] = 0.5 M. The formation of silver dithiosulfate complex (Ag(S2O323− was confirmed by the characterization of the leach liquors obtained from the experiments performed in the temperature range of 298 to 333 K using Fourier transform infrared spectroscopy (FTIR.

Anodic stripping voltammetry of synthesized CdS nanoparticles at boron-doped diamond electrodes

Energy Technology Data Exchange (ETDEWEB)

Hayat, Mohammad; Ivandini, Tribidasari A., E-mail: ivandini.tri@sci.ui.ac.id; Saepudin, Endang [Department of Chemistry, FMIPA, Universitas Indonesia, Kampus UI Depok (Indonesia); Einaga, Yasuaki [Department of Chemistry, Keio University (Japan)

2016-04-19

Cadmium sulphide (CdS) nanoparticles were chemically synthesized using reverse micelles microreactor methods. By using different washing treatments, UV-Vis spectroscopy showed that the absorption peaks appeared at 465 nm, 462 nm, 460 nm, and 459 nm respectively for CdS nanoparticles without and with 1, 2, and 3 times washing treatments using pure water. In comparison with the absorbance peak of bulk CdS at 512 nm, the shifted absorption peaks, indicates that the different sizes of CdS can be prepared. Anodic stripping voltammetry of the CdS nanoparticles was then studied at a boron-doped diamond electrode using 0.1 M KClO{sub 4} and 0.1 M HClO{sub 4} as the electrolytes. A scan rate of 100 mV/s with a deposition potential of -1000 mV (vs. Ag/AgCl) for 60 s at a potential scan from -1600 mV to +800 mV (vs. Ag/AgCl) was applied as the optimum condition of the measurements. Highly-accurate linear calibration curves (R{sup 2} = 0.99) in 0.1 M HClO{sub 4} with the sensitivity of 0.075 mA/mM and the limit of detection of 81 µM in 0.1 M HClO{sub 4} can be achieved, which is promising for an application of CdS nanoparticles as a label for biosensors.

Close linkage of the mouse and human CD3 γ- and δ-chain genes suggests that their transcription is controlled by common regulatory elements

International Nuclear Information System (INIS)

Saito, H.; Koyama, T.; Georgopoulos, K.; Clevers, H.; Haser, W.G.; LeBien, T.; Tonegawa, S.; Terhorst, C.

1987-01-01

Antigen receptors on the T-cell surface are noncovalently associated with at least four invariant polypeptide chains, CD3-γ, -δ, -epsilon, and -zeta. The mouse CD3-γ gene, consisting of seven exons, was found to be highly homologous to the CD3-γ described earlier. Both the high level of sequence homology and the exon/intron organization indicate that the CD3-γ and -δ genes arose by gene duplication. Surprisingly, murine and human genomic DNA clones could be isolated that contained elements of both the CD3-γ and CD3-δ genes. In fact, the putative transcription start site of the mouse CD3-γ gene is less than 1.4 kilobases from the transcription initiation site of the mouse CD3-δ gene. Common elements that regulate the divergent transcription of the two genes are therefore proposed to be located in the intervening 1.4-kilobase DNA segment. This might contribute to the coordinate expression of the CD3-γ and -δ genes during intrathymic maturation of T lymphocytes

Influence of dopant concentration on the electrical properties of the CdSe-PMMA nanocomposite

Energy Technology Data Exchange (ETDEWEB)

Kaur, Ramneek; Tripathi, S. K., E-mail: surya@pu.ac.in, E-mail: surya-tr@yahoo.com [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh-160 014 (India)

2016-05-06

This paper reports the synthesis and electrical characterization of CdSe-PMMA nanocomposite. CdSe-PMMA nanocomposite has been prepared by ex-situ technique through chemical route. The influence of three different Ag doping concentrations on the electrical properties has been studied in the temperature range ∼ 303-353 K. Transmission electron micrograph reveals the spherical morphology of the CdSe nanoparticles and their proper dispersion in the PMMA matrix. The electrical conduction of the polymer nanocomposites is through thermally activated process with single activation energy. With Ag doping, initially the activation energy increases upto 0.2 % Ag doping concentration but with further increase in Ag concentration, it decreases. This behavior has been discussed on the basis of randomly oriented grain boundaries and defect states. Thus, the results indicate that the transport properties of the polymer nanocomposites can be tailored by controlled doping concentration.

Influence of dopant concentration on the electrical properties of the CdSe-PMMA nanocomposite

International Nuclear Information System (INIS)

Kaur, Ramneek; Tripathi, S. K.

2016-01-01

This paper reports the synthesis and electrical characterization of CdSe-PMMA nanocomposite. CdSe-PMMA nanocomposite has been prepared by ex-situ technique through chemical route. The influence of three different Ag doping concentrations on the electrical properties has been studied in the temperature range ∼ 303-353 K. Transmission electron micrograph reveals the spherical morphology of the CdSe nanoparticles and their proper dispersion in the PMMA matrix. The electrical conduction of the polymer nanocomposites is through thermally activated process with single activation energy. With Ag doping, initially the activation energy increases upto 0.2 % Ag doping concentration but with further increase in Ag concentration, it decreases. This behavior has been discussed on the basis of randomly oriented grain boundaries and defect states. Thus, the results indicate that the transport properties of the polymer nanocomposites can be tailored by controlled doping concentration.

Dissolved trace metal (Cu, Cd, Co, Ni, and Ag) distribution and Cu speciation in the southern Yellow Sea and Bohai Sea, China

Science.gov (United States)

Li, Li; Xiaojing, Wang; Jihua, Liu; Xuefa, Shi

2017-02-01

Trace metals play an important role in biogeochemical cycling in ocean systems. However, because the use of trace metal clean sampling and analytical techniques has been limited in coastal China, there are few accurate trace metal data for that region. This work studied spatial distribution of selected dissolved trace metals (Ag, Cu, Co, Cd, and Ni) and Cu speciation in the southern Yellow Sea (SYS) and Bohai Sea (BS). In general, the average metal (Cu, Co, Cd, and Ni) concentrations found in the SYS were lower by a factor of two than those in BS, and they are comparable to dissolved trace metal concentrations in coastal seawater of the United States and Europe. Possible sources and sinks and physical and biological processes that influenced the distribution of these trace metals in the study region were further examined. Close relationships were found between the trace metal spatial distribution with local freshwater discharge and processes such as sediment resuspension and biological uptake. Ag, owing to its extremely low concentrations, exhibited a unique distribution pattern that magnified the influences from the physical and biological processes. Cu speciation in the water column showed that, in the study region, Cu was strongly complexed with organic ligands and concentrations of free cupric ion were in the range of 10-12.6-10-13.2 mol L-1. The distribution of Cu-complexing ligand, indicated by values of the side reaction coefficient α', was similar to the Chl a distribution, suggesting that in situ biota production may be one main source of Cu-complexing organic ligand.

Microstructure, electrical conductivity and modulus spectra of CdI{sub 2} doped nanocomposite-electrolytes

Energy Technology Data Exchange (ETDEWEB)

Kundu, Ranadip [Department of Engineering Sciences and Humanities, Siliguri Institute of Technology, Darjeeeling 734009, West Bengal (India); Department of Mechanical Engineering, Jadavpur University, Jadavpur, Kolkata 700032 (India); Roy, Debasish [Department of Mechanical Engineering, Jadavpur University, Jadavpur, Kolkata 700032 (India); Bhattacharya, Sanjib, E-mail: sanjib_ssp@yahoo.co.in [Department of Engineering Sciences and Humanities, Siliguri Institute of Technology, Darjeeeling 734009, West Bengal (India)

2017-02-15

Ionic conductivity and dielectric behavior of Ag{sub 2}O–CdI{sub 2}–CdO nanocomposite system have been studied. X-ray diffraction has been carried out to obtain the crystallite sizes and the growth of CdO dispersed in glass-matrices. Total conductivity of them shows thermally activated nature. It is observed that total conductivity decreases and corresponding activation energy for conduction follows opposite behavior. The high-frequency ac conductivity may correspond to a nonrandom, correlated and sub-diffusive motion of Ag{sup +} ions. Conductivity relaxation time is found to increase. The nature of scaling of the conductivity as well as modulus spectra indicates that the electrical relaxation of Ag{sup +} is temperature independent but depends upon composition.

Progress in Solving the Elusive Ag Transport Mechanism in TRISO Coated Particles: What is new?

Energy Technology Data Exchange (ETDEWEB)

Isabella Van Rooyen

2014-10-01

The TRISO particle for HTRs has been developed to an advanced state where the coating withstands internal gas pressures and retains fission products during irradiation and under postulated accidents. However, one exception is Ag that has been found to be released from high quality TRISO coated particles when irradiated and can also during high temperature accident heating tests. Although out- of- pile laboratory tests have never hither to been able to demonstrate a diffusion process of Ag in SiC, effective diffusion coefficients have been derived to successfully reproduce measured Ag-110m releases from irradiated HTR fuel elements, compacts and TRISO particles It was found that silver transport through SiC does not proceed via bulk volume diffusion. Presently grain boundary diffusion that may be irradiation enhanced either by neutron bombardment or by the presence of fission products such as Pd, are being investigated. Recent studies of irradiated AGR-1 TRISO fuel using scanning transmission electron microscopy (STEM), transmission kukuchi diffraction (TKD) patterns and high resolution transmission electron microscopy (HRTEM) have been used to further the understanding of Ag transport through TRISO particles. No silver was observed in SiC grains, but Ag was identified at triple-points and grain boundaries of the SiC layer in the TRISO particle. Cadmium was also found in some of the very same triple junctions, but this could be related to silver behavior as Ag-110m decays to Cd-110. Palladium was identified as the main constituent of micron-sized precipitates present at the SiC grain boundaries and in most SiC grain boundaries and the potential role of Pd in the transport of Ag will be discussed.

Contents of trace elements in meadow mushrooms as results of PIXE, NAA and AAS measurements

International Nuclear Information System (INIS)

Urban, J.; Sieniawski, J.

1992-01-01

Contents of heavy elements in mushrooms from the Dresden area and from some parts of Poland, by use of three methods of measurement (PIXE, AAS and NAA) were determined, with the special interest focused on wild growing and cultivated meadow mushrooms. The ability for accumulation of Se, Cu, Ag and Cu was established. In some wild growing mushrooms the values of Cd, Hg, As and Pb exceeded allowed limits for human nutrition. (author). 16 refs, 1 fig., 5 tabs

INTERACTION OF SILVER MOLECULAR CLUSTERS, INTRODUCED BY LOW-TEMPERATURE ION EXCHANGE METHOD, WITH NANOPARTICLES OF CdS IN FLUORINE PHOSPHATE GLASSES

Directory of Open Access Journals (Sweden)

N. D. Grazhdanov

2015-09-01

Full Text Available Glasses with metallic and semi-conductive nano-particles appear to be perspective non-linear and luminescent materials of photonics. It was shown in theory that composite optical materials containing semi-conductive CdS-core with Ag shell (or vice versa are optimal for enhancement of non-linear Kerr effect. Interaction of such an ensemble of particles leads to the forming of Ag island structures on the CdS particle, and formation of acanthite Ag2S on the two phases border (CdS-Ag is minimal. In glasses synthesis of CdS quantum dots occurred due to thermal treatment close to glass transition temperature; introduction of silver was realized by low-temperature ion exchange (LIE. The main object of this work is investigation of Ag+ -LIE effect on the growth of CdS nano-particles. Two glasses were explored in this work: without CdS (glass 1 and with CdS (glass 2, processed by LIE at the temperature of 320°С for 10, 20 and 30 minutes and subsequent heat treatment at temperatures of 410°С and 420°С. In case of glass 1, intensive luminescence appears as a result of LIE, and subsequent heat treatment results in surface resonance at λ=410 nm. In case of glass 2, absorbance spectra change appears that is specific for formation of acanthite and weak luminescence shifting to long-wavelength region (from 550 to 700 nm as a result of applying LIE and heat treatment. It indicates the growth of CdS quantum dots. Experiment has shown that quantum efficiency increases to 70% for glass 2 containing CdS quantum dots without LIE, while glass that contains silver shows steep decrease of quantum efficiency to 0%. That decrease is caused by formation of acanthite Ag2S on the surface of CdS quantum dot.

Nuclear-physical properties of 105,106m,110mAg

International Nuclear Information System (INIS)

Popov, Yu. S.; Zakharova, L. V.; Sadulin, V. V.; Andreev, O. I.; Pakhomov, A. N.

2005-01-01

The nuclear-physical properties of the nuclides 105,106m,110m Ag, which are concomitant nuclides in reactor production of 103 Pd and 109 Cd used in metrology of ionizing radiations and in nuclear medicine, were studied. The following quantities were determined by semiconductor X-ray and γ-ray spectrometry: the parameter K α /K β of X-ray K radiation accompanying the decay of 110m Ag and the intensities of γ-ray quanta with the energies of 280 and 345 keV ( 105 Ag); 430, 451, and 512 keV ( 106m Ag); 658, 764, 885, 938, and 1384 keV ( 110m Ag). The half-lives determined using the above γ-ray lines are as follows: T 1/2 ( 105 Ag) = 41.2 ± 0.1 days; T 1/2 ( 106m Ag) = 8.30 ± 0.07 days. The errors are given for 95% confidence level [ru

Quantitative HBsAg and HBeAg predict hepatitis B seroconversion after initiation of HAART in HIV-HBV coinfected individuals.

Directory of Open Access Journals (Sweden)

Gail V Matthews

Full Text Available OBJECTIVE: Anti-HBe seroconversion and HBsAg loss are important therapeutic endpoints in patients with hepatitis B virus (HBV infection. Quantitative measures of hepatitis B surface antigen (qHBsAg and e antigen (qHBeAg have been identified as potentially useful indicators of therapeutic response in HBV monoinfection. The aim of this study was to examine serological change including quantitative biomarkers in HIV-HBV coinfected patients initiating HBV active antiretroviral therapy (ART. METHODS: HIV-HBV coinfected individuals from Thailand were followed for up to 168 weeks post ART. Rates and associations of qualitative serological change were determined. Longitudinal changes in qHBsAg and qHBeAg were measured and their utility as predictors of response examined. RESULTS: Forty seven patients were included of whom 27 (57% were HBeAg positive at baseline. Median CD4 count was 48 cells/mm(3. Over a median follow-up of 108 weeks 48% (13/27 lost HBeAg, 12/27 (44% achieved anti-HBe seroconversion and 13% (6/47 HBsAg loss. Anti-HBe seroconversion was associated with higher baseline ALT (p = 0.034, lower qHBsAg (p = 0.015, lower qHBeAg (p = 0.031 and greater HBV DNA decline to week 24 (p = 0.045. Sensitivity and specificity for qHBsAg and qHBeAg decline of >0.5 log at week 12 and >1.0 log at week 24 were high for both anti-HBe seroconversion and HBsAg loss. CONCLUSIONS: Rates of serological change in these HIV-HBV coinfected individuals with advanced immunodeficiency initiating HBV-active ART were high. Baseline and on treatment factors were identified that were associated with a greater likelihood of subsequent anti-HBe seroconversion, including both quantitative HBsAg and HBeAg, suggesting these biomarkers may have utility in this clinical setting.

Existence of CD8α-like dendritic cells with a conserved functional specialization and a common molecular signature in distant mammalian species.

Science.gov (United States)

Contreras, Vanessa; Urien, Céline; Guiton, Rachel; Alexandre, Yannick; Vu Manh, Thien-Phong; Andrieu, Thibault; Crozat, Karine; Jouneau, Luc; Bertho, Nicolas; Epardaud, Mathieu; Hope, Jayne; Savina, Ariel; Amigorena, Sebastian; Bonneau, Michel; Dalod, Marc; Schwartz-Cornil, Isabelle

2010-09-15

The mouse lymphoid organ-resident CD8alpha(+) dendritic cell (DC) subset is specialized in Ag presentation to CD8(+) T cells. Recent evidence shows that mouse nonlymphoid tissue CD103(+) DCs and human blood DC Ag 3(+) DCs share similarities with CD8alpha(+) DCs. We address here whether the organization of DC subsets is conserved across mammals in terms of gene expression signatures, phenotypic characteristics, and functional specialization, independently of the tissue of origin. We study the DC subsets that migrate from the skin in the ovine species that, like all domestic animals, belongs to the Laurasiatheria, a distinct phylogenetic clade from the supraprimates (human/mouse). We demonstrate that the minor sheep CD26(+) skin lymph DC subset shares significant transcriptomic similarities with mouse CD8alpha(+) and human blood DC Ag 3(+) DCs. This allowed the identification of a common set of phenotypic characteristics for CD8alpha-like DCs in the three mammalian species (i.e., SIRP(lo), CADM1(hi), CLEC9A(hi), CD205(hi), XCR1(hi)). Compared to CD26(-) DCs, the sheep CD26(+) DCs show 1) potent stimulation of allogeneic naive CD8(+) T cells with high selective induction of the Ifngamma and Il22 genes; 2) dominant efficacy in activating specific CD8(+) T cells against exogenous soluble Ag; and 3) selective expression of functional pathways associated with high capacity for Ag cross-presentation. Our results unravel a unifying definition of the CD8alpha(+)-like DCs across mammalian species and identify molecular candidates that could be used for the design of vaccines applying to mammals in general.

Interaction between impurities in Ag dilute alloys

International Nuclear Information System (INIS)

Krolas, K.; Wodniecka, B.; Wodniecki, P.; Uniwersytet Jagiellonski, Krakow

1977-01-01

Time dependent perturbed angular correlation measurements of gamma radiation in 111 Cd after 111 In decay were performed in AgPd and AgPt alloys. The concentration of Pd or Pt atoms being the nearest neighbours to the probe atoms is much higher than that one deduced from random impurity distribution. This effect results from the attractive interaction between the In probe atoms and Pt or Pd impurity atoms in silver host lattice. The binding energy of InPd and InPt complexes was measured as 135 +- 9 meV and 171 +- 9 meV, respectively. (author)

Heat shock protein 90-mediated peptide-selective presentation of cytosolic tumor antigen for direct recognition of tumors by CD4(+) T cells.

Science.gov (United States)

Tsuji, Takemasa; Matsuzaki, Junko; Caballero, Otavia L; Jungbluth, Achim A; Ritter, Gerd; Odunsi, Kunle; Old, Lloyd J; Gnjatic, Sacha

2012-04-15

Tumor Ag-specific CD4(+) T cells play important functions in tumor immunosurveillance, and in certain cases they can directly recognize HLA class II-expressing tumor cells. However, the underlying mechanism of intracellular Ag presentation to CD4(+) T cells by tumor cells has not yet been well characterized. We analyzed two naturally occurring human CD4(+) T cell lines specific for different peptides from cytosolic tumor Ag NY-ESO-1. Whereas both lines had the same HLA restriction and a similar ability to recognize exogenous NY-ESO-1 protein, only one CD4(+) T cell line recognized NY-ESO-1(+) HLA class II-expressing melanoma cells. Modulation of Ag processing in melanoma cells using specific molecular inhibitors and small interfering RNA revealed a previously undescribed peptide-selective Ag-presentation pathway by HLA class II(+) melanoma cells. The presentation required both proteasome and endosomal protease-dependent processing mechanisms, as well as cytosolic heat shock protein 90-mediated chaperoning. Such tumor-specific pathway of endogenous HLA class II Ag presentation is expected to play an important role in immunosurveillance or immunosuppression mediated by various subsets of CD4(+) T cells at the tumor local site. Furthermore, targeted activation of tumor-recognizing CD4(+) T cells by vaccination or adoptive transfer could be a suitable strategy for enhancing the efficacy of tumor immunotherapy.

Ag Isotopic Evolution of the Mantle During Accretion: New Constraints from Pd and Ag Metal-Silicate Partitioning

Science.gov (United States)

Righter, K.; Schonbachler, M.

2018-01-01

Decay of (sup 107) Pd to (sup 107) Ag has a half-life of 6.5 times 10 (sup 6) mega-annums. Because these elements are siderophile but also volatile, they offer potential constraints on the timing of core formation as well as volatile addition. Initial modelling has shown that the Ag isotopic composition of the bulk silicate Earth (BSE) can be explained if accretion occurs with late volatile addition. These arguments were tested for sensitivity for pre-cursor Pd/Ag contents, and for a fixed Pd/Ag ratio of the BSE of 0.1. New Ag and Pd partitioning data has allowed a better understanding of the partitioning behavior of Pd and Ag during core formation. The effects of S, C and Si, and the effect of high temperature and pressure has been evaluated. We can now calculate D(Ag) and D(Pd) over the wide range of PT conditions and variable metallic liquid compositions that are known during accretion. We then use this new partitioning information to revisit the Ag isotopic composition of the BSE during accretion.

Bio- and toxic elements in edible wild mushrooms from two regions of potentially different environmental conditions in eastern Poland.

Science.gov (United States)

Brzezicha-Cirocka, Justyna; Mędyk, Małgorzata; Falandysz, Jerzy; Szefer, Piotr

2016-11-01

In the present study, the composition of bio-elements (K, Na, Mg, Ca, Fe, Cu, Zn) and toxic elements (Ag, Cd) in seven edible mushrooms from the rural and woodland region of Morąg (north-eastern Poland) and the rural and industrial region of the Tarnobrzeska Upland (south-eastern Poland) were investigated using a validated method. The species examined were Boletus edulis, Cantharellus cibarius, Leccinum aurantiacum, Leccinum versipelle, Lycoperdon perlatum, Suillus luteus, and Xerocomus subtomentosus. Final determination was carried out by flame atomic absorption spectroscopy (FAAS) after microwave-assisted decomposition of sample matrices with solutions of concentrated nitric acid in the pressurized polytetrafluoroethylene vessels. The contents of the alkali elements and alkali earth elements were determined in the species surveyed. The alkali elements, earth alkali elements, and transition metals (Ag, Cu, Zn, Fe, and Mn) were at typical concentrations as was determined for the same or similar species elsewhere in Poland and Europe. The results may suggest a lack of local and regional emissions of those metallic elements from industrialization of some sites in the Tarnobrzeska Plain. Cadmium was at elevated concentrations in L. versipelle from the Tarnobrzeska Plain but the reason-pollution or geogenic source-was unknown, while it was at typical concentrations in other species.

Concentrations of major and trace elements in polished rice and paddy soils collected in Aomori, Japan

International Nuclear Information System (INIS)

Tsukada, H.; Hasegawa, H.; Takeda, A.; Hisamatsu, S.

2005-01-01

Rice is a staple food in most Asian countries including Japan, and it is important to evaluate the intake of elements through polished rice ingestion in daily life. Rice grain samples and surface paddy soil samples were collected from 20 sites throughout Aomori Prefecture, Japan. Rice grains were threshed and then polished to 90% of the total weight of brown rice. The polished rice samples for the determination of the neutron activation analysis (NAA) were dried at 50 degree C and those of the inductively coupled plasma-mass spectrometer (ICP-MS) were ashed at a temperature below 450 degree C to avoid loss of alkali metals. The soil samples were dried at 50 degree C and were pulverized with an agate ball mill. The concentrations of As, Cl and I in the polished rice and As, Cl, I, Ti and Zr in the soils were determined by the NAA. The concentrations of 22 elements in the polished rice and 28 elements in the soils were determined by the ICP-MS. The mean concentrations of essential elements in the polished rice such as K, Mg, Cl, Ca, Zn, Mn, Fe, Cu and Mo were 720, 270, 160, 54, 16, 9.7, 2.3, 21 and 0.47 mg kg -1 dry weight, respectively, and the range of each element was within one order of magnitude. However, the ranges of most trace elements in the polished rice including Al, Ni, Ba, Cd, Pb, Cr, I, Ag and Cs were more than one order of magnitude. The mean concentrations of non-essential elements in the polished rice were as follows: Na, 11; Al, 3.9; Rb, 1.2; Ni, 0.11; As, Sr, Ba, Cd, V and Pb, 0.1-0.01; Cr, I, Co, Ag, Se and Cs, O.Ol-0.001 mg kg -1 dry weight. The concentration ranges of elements, except for I, in the paddy soils were within one order of magnitude. The mean concentrations of elements in the soils were as follows: Al, Fe, Ca and Na, 100000-10000; Mg, K and Ti, 10000-1000; Mn, Ba, Cl, Zr, Sr and Zn, 1000-100; V, Ce, Cr, Rb, Cu, Pb, Sc, La, As and Ni, 100-10; Co, Th, Cs, I, U, Mo and Se, 10-1; Sb, Cd and Ag, 1-0.1 mg kg -1 . The mean concentrations of

DETERMINATION OF LIMIT DETECTION OF THE ELEMENTS N, P, K, Si, Al, Fe, Cu, Cd, WITH FAST NEUTRON ACTIVATION USING NEUTRON GENERATOR

OpenAIRE

Sunardi, Sunardi; Muryono, Muryono

2010-01-01

Determination of limit detection of the elements N, P, K, Si, Al, Fe, Cu, Cd, with fast neutron activation using neutron generator has been done.  Samples prepared from SRM 2704, N, P, K elements from MERCK, Cu, Cd, Al from activation foil made in San Carlos, weighted and packed for certain weight then iradiated during 30 minutes with 14 MeV fast neutron using the neutron generator and then counted with gamma spectrometry (accuspec).  At this research condition of neutron generator was set at...

Trace elements in muscle of three fish species from Todos os Santos Bay, Bahia State, Brazil.

Science.gov (United States)

de Santana, Carolina Oliveira; de Jesus, Taíse Bomfim; de Aguiar, William Moura; de Jesus Sant'anna Franca-Rocha, Washington; Soares, Carlos Alberto Caroso

2017-03-01

In this study, an analysis was performed on the concentrations of the trace elements Al, As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn in muscle of two carnivorous and one planktivorous fish species collected at Todos os Santos Bay (BTS). The accumulation order of the trace elements in Lutjanus analis was Al >Zn >Fe >Cr >Ba >Ni. In Cetengraulis edentulus, the order was Al >Fe >Zn >Cr >Ni >Mn >As. In the species Diapterus rhombeus, the order was Al >Fe >Zn >Cr >Ni >Mn >Cd. To determine the risk related to the consumption of fish, toxicity guidelines were used as standard references. It was observed that the species C. edentulus contained concentrations of As exceeding WHO limits, but these concentrations were acceptable according to the Agência Nacional de Vigilância Sanitária (ANVISA) guidelines. Cd levels were found only in D. rhombeus and in low concentrations according to the determinations of WHO and ANVISA. Pb levels were not detected in any of the three fish species. The analyzed elements did not differ statistically according to the species and feeding habits. The results point to possible risks of human contamination by As related to the consumption of the fish species C. edentulus from the BTS.

Association between CTLA-4 gene promoter (49 A/G) in exon 1 polymorphisms and inflammatory bowel disease in the Tunisian population

International Nuclear Information System (INIS)

Alaya, Walid Ben; Sfar, Imen; Aouadi, Houda; Jendoubi, Saloua; Najjar, Tawfik; Filali, Azza; Gorgi, Yousr; Abdallah, Taieb Ben; Mouelhi, Leila; Matri, Samira; Ayed, Khaled

2009-01-01

To investigate the possible association between the polymorphism of the CTLA-4 exon 1 +49 A/G and susceptibility to Crohn's disease (CD) and ulcerative colitis (UC) in the Tunisian population. The +49 A/G dimorphism was analyzed in 119 patients with CD, 65 patients with UC, and 100 controls by the polymerase chain reaction-restriction fragment length polymorphism method. Significantly higher frequencies of the CTLA-4 +49A allele and A/A homozygous individuals were observed in patients with CD when compared with controls (pc = 0.0023 and pc = 0.0003, respectively). Analysis of CTLA-4 A/G polymorphism with respect to sex in CD showed a significant difference in A/A genotypes between female patients and controls (pc = 0.0001 and pc = 0.038, respectively). There were no differences in the subgroups of patients with CD. Forty-nine A alleles and AA genotype are associated with CD susceptibility in Tunisians. Other genes involved in the T-cell regulation remain strong candidates for IBD susceptibility and require further investigation. (author)

Vertical distribution of elements in non-polluted estuarine sediments determined by neutron induced prompt gamma-ray and instrumental neutron activation analyses

International Nuclear Information System (INIS)

Kuno, A.; Sampei, K.; Matsuo, M.; Sawahata, H.

1999-01-01

Neutron induced prompt gamma-ray analysis (PGA) and instrumental neutron activation analysis (INAA) have been applied to the sediments collected from the Yasaka River estuary in Oita Prefecture, Japan. The vertical distribution of 33 elements in the sediments has been determined and compared with that in more polluted estuarine sediments. While the S content increased with increasing depth because of a sulphide accumulation under reducing condition, the increase in sulphide-forming elements such as Ag, Cd, Co and Zn was not observed in the deeper section of the Yasaka River estuarine sediments. (author)

DETERMINATION OF LIMIT DETECTION OF THE ELEMENTS N, P, K, Si, Al, Fe, Cu, Cd, WITH FAST NEUTRON ACTIVATION USING NEUTRON GENERATOR

Directory of Open Access Journals (Sweden)

Sunardi Sunardi

2010-06-01

Full Text Available Determination of limit detection of the elements N, P, K, Si, Al, Fe, Cu, Cd, with fast neutron activation using neutron generator has been done.  Samples prepared from SRM 2704, N, P, K elements from MERCK, Cu, Cd, Al from activation foil made in San Carlos, weighted and packed for certain weight then iradiated during 30 minutes with 14 MeV fast neutron using the neutron generator and then counted with gamma spectrometry (accuspec.  At this research condition of neutron generator was set at current 1 mA that produced neutron flux about 5,47.107 n/cm2.s and  experimental result shown that the limit detection for the elements N, P, K, Si, Al, Fe, Cu, Cd are  2,44 ppm, 1,88 ppm, 2,15 ppm, 1,44 ppm, 1,26 ppm, 1,35 ppm, 1,05 ppm, 2,99 ppm, respectively.  The data  indicate that the limit detection or sensitivity of appliance of neutron generator to analyze the element is very good, which is feasible to get accreditation AANC laboratory using neutron generator.   Keywords: limit detection, AANC, neutron generator

Origin of the Distinct Diffusion Behaviors of Cu and Ag in Covalent and Ionic Semiconductors.

Science.gov (United States)

Deng, Hui-Xiong; Luo, Jun-Wei; Li, Shu-Shen; Wei, Su-Huai

2016-10-14

It is well known that Cu diffuses faster than Ag in covalent semiconductors such as Si, which has prevented the replacement of Ag by Cu as a contact material in Si solar cells for reducing the cost. Surprisingly, in more ionic materials such as CdTe, Ag diffuses faster than Cu despite that it is larger than Cu, which has prevented the replacement of Cu by Ag in CdTe solar cells to improve the performance. But, so far, the mechanisms behind these distinct diffusion behaviors of Cu and Ag in covalent and ionic semiconductors have not been addressed. Here we reveal the underlying mechanisms by combining the first-principles calculations and group theory analysis. We find that the symmetry controlled s-d coupling plays a critical role in determining the diffusion behaviors. The s-d coupling is absent in pure covalent semiconductors but increases with the ionicity of the zinc blende semiconductors, and is larger for Cu than for Ag, owing to its higher d orbital energy. In conjunction with Coulomb interaction and strain energy, the s-d coupling is able to explain all the diffusion behaviors from Cu to Ag and from covalent to ionic hosts. This in-depth understanding enables us to engineer the diffusion of impurities in various semiconductors.

Rapid Colorimetric Detection of Cartap Residues by AgNP Sensor with Magnetic Molecularly Imprinted Microspheres as Recognition Elements

Directory of Open Access Journals (Sweden)

Mao Wu

2018-06-01

Full Text Available The overuse of cartap in tea tree leads to hazardous residues threatening human health. A colorimetric determination was established to detect cartap residues in tea beverages by silver nanoparticles (AgNP sensor with magnetic molecularly imprinted polymeric microspheres (Fe3O4@mSiO2@MIPs as recognition elements. Using Fe3O4 as supporting core, mesoporous SiO2 as intermediate shell, methylacrylic acid as functional monomer, and cartap as template, Fe3O4@mSiO2@MIPs were prepared to selectively and magnetically separate cartap from tea solution before colorimetric determination by AgNP sensors. The core-shell Fe3O4@mSiO2@MIPs were also characterized by FT-IR, TEM, VSM, and experimental adsorption. The Fe3O4@mSiO2@MIPs could be rapidly separated by an external magnet in 10 s with good reusability (maintained 95.2% through 10 cycles. The adsorption process of cartap on Fe3O4@mSiO2@MIPs conformed to Langmuir adsorption isotherm with maximum adsorption capacity at 0.257 mmol/g and short equilibrium time of 30 min at 298 K. The AgNP colorimetric method semi-quantified cartap ≥5 mg/L by naked eye and quantified cartap 0.1–5 mg/L with LOD 0.01 mg/L by UV-vis spectroscopy. The AgNP colorimetric detection after pretreatment with Fe3O4@mSiO2@MIPs could be successfully utilized to recognize and detect cartap residues in tea beverages.

Associations between CD36 gene polymorphisms and susceptibility to coronary artery heart disease

International Nuclear Information System (INIS)

Zhang, Y.; Ling, Z.Y.; Deng, S.B.; Du, H.A.; Yin, Y.H.; Yuan, J.; She, Q.; Chen, Y.Q.

2014-01-01

Associations between polymorphisms of the CD36 gene and susceptibility to coronary artery heart disease (CHD) are not clear. We assessed allele frequencies and genotype distributions of CD36 gene polymorphisms in 112 CHD patients and 129 control patients using semi-quantitative polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis. Additionally, we detected CD36 mRNA expression by real-time quantitative PCR, and we quantified plasma levels of oxidized low-density lipoprotein (ox-LDL) using an enzyme-linked immunosorbent assay (ELISA). There were no significant differences between the two groups (P>0.05) in allele frequencies of rs1761667 or in genotype distribution and allele frequencies of rs3173798. The genotype distribution of rs1761667 significantly differed between CHD patients and controls (P=0.034), with a significantly higher frequency of the AG genotype in the CHD group compared to the control group (P=0.011). The plasma levels of ox-LDL in patients with the AG genotype were remarkably higher than those with the GG and AA genotypes (P=0.010). In a randomized sample taken from patients in the two groups, the CD36 mRNA expression of the CHD patients was higher than that of the controls. In CHD patients, the CD36 mRNA expression in AG genotype patients was remarkably higher than in those with an AA genotype (P=0.005). After adjusted logistic regression analysis, the AG genotype of rs1761667 was associated with an increased risk of CHD (OR=2.337, 95% CI=1.336-4.087, P=0.003). In conclusion, the rs1761667 polymorphism may be closely associated with developing CHD in the Chongqing Han population of China, and an AG genotype may be a genetic susceptibility factor for CHD

Associations between CD36 gene polymorphisms and susceptibility to coronary artery heart disease

Energy Technology Data Exchange (ETDEWEB)

Zhang, Y.; Ling, Z.Y.; Deng, S.B.; Du, H.A.; Yin, Y.H.; Yuan, J.; She, Q.; Chen, Y.Q. [Department of Cardiology, The Second Affiliated Hospital, Chongqing Medical University, Chongqing (China)

2014-08-08

Associations between polymorphisms of the CD36 gene and susceptibility to coronary artery heart disease (CHD) are not clear. We assessed allele frequencies and genotype distributions of CD36 gene polymorphisms in 112 CHD patients and 129 control patients using semi-quantitative polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis. Additionally, we detected CD36 mRNA expression by real-time quantitative PCR, and we quantified plasma levels of oxidized low-density lipoprotein (ox-LDL) using an enzyme-linked immunosorbent assay (ELISA). There were no significant differences between the two groups (P>0.05) in allele frequencies of rs1761667 or in genotype distribution and allele frequencies of rs3173798. The genotype distribution of rs1761667 significantly differed between CHD patients and controls (P=0.034), with a significantly higher frequency of the AG genotype in the CHD group compared to the control group (P=0.011). The plasma levels of ox-LDL in patients with the AG genotype were remarkably higher than those with the GG and AA genotypes (P=0.010). In a randomized sample taken from patients in the two groups, the CD36 mRNA expression of the CHD patients was higher than that of the controls. In CHD patients, the CD36 mRNA expression in AG genotype patients was remarkably higher than in those with an AA genotype (P=0.005). After adjusted logistic regression analysis, the AG genotype of rs1761667 was associated with an increased risk of CHD (OR=2.337, 95% CI=1.336-4.087, P=0.003). In conclusion, the rs1761667 polymorphism may be closely associated with developing CHD in the Chongqing Han population of China, and an AG genotype may be a genetic susceptibility factor for CHD.

Use of reference materials for quality control of elemental analysis by neutron activation with radiochemical separation

International Nuclear Information System (INIS)

Woittiez, J.R.W.

1990-01-01

This paper describes the use of certified reference materials to monitor the long-term quality of radiochemical separations. The practical limitations which determine the actual design of the quality control are discussed. The hypothesis that the high yield of the radiochemical separation will be constant with time has been checked and validated for the elements Zn, Fe, Co, Cd, Mo and to a lesser extent for W and Th using NBS SRM 1577A, BCR CRM 274 and IAEA RM A-11. This validation could not be made for the elements Cr, Au, and Ag. Especially for Cr there is a serious lack of appropiate certified reference materials. (orig.)

CD209 genetic polymorphism and tuberculosis disease.

Directory of Open Access Journals (Sweden)

Fredrik O Vannberg

2008-01-01

Full Text Available Tuberculosis causes significant morbidity and mortality worldwide, especially in sub-Saharan Africa. DC-SIGN, encoded by CD209, is a receptor capable of binding and internalizing Mycobacterium tuberculosis. Previous studies have reported that the CD209 promoter single nucleotide polymorphism (SNP-336A/G exerts an effect on CD209 expression and is associated with human susceptibility to dengue, HIV-1 and tuberculosis in humans. The present study investigates the role of the CD209 -336A/G variant in susceptibility to tuberculosis in a large sample of individuals from sub-Saharan Africa.A total of 2,176 individuals enrolled in tuberculosis case-control studies from four sub-Saharan Africa countries were genotyped for the CD209 -336A/G SNP (rs4804803. Significant overall protection against pulmonary tuberculosis was observed with the -336G allele when the study groups were combined (n = 914 controls vs. 1262 cases, Mantel-Haenszel 2 x 2 chi(2 = 7.47, P = 0.006, odds ratio = 0.86, 95%CI 0.77-0.96. In addition, the patients with -336GG were associated with a decreased risk of cavitory tuberculosis, a severe form of tuberculosis disease (n = 557, Pearson's 2x2 chi(2 = 17.34, P = 0.00003, odds ratio = 0.42, 95%CI 0.27-0.65. This direction of association is opposite to a previously observed result in a smaller study of susceptibility to tuberculosis in a South African Coloured population, but entirely in keeping with the previously observed protective effect of the -336G allele.This study finds that the CD209 -336G variant allele is associated with significant protection against tuberculosis in individuals from sub-Saharan Africa and, furthermore, cases with -336GG were significantly less likely to develop tuberculosis-induced lung cavitation. Previous in vitro work demonstrated that the promoter variant -336G allele causes down-regulation of CD209 mRNA expression. Our present work suggests that decreased levels of the DC-SIGN receptor may therefore be

The elements distribution of Fe, Cd, Ca, Co and Cr on the well water and river in area Wonosari Gunung Kidul

International Nuclear Information System (INIS)

Rosidi; Agus Taftazani; Sukirno

2010-01-01

The analysis of Fe, Cd, Ca, Co and Cr on the well water and river were detected by γ spectrometer with HPGe detector using NAA method. The main objective of this research was carried out to characterize the Fe, Cd, Ca, Co and Cr on the well water and river in area Gunung Kidul Yogyakarta, which accommodate of the present of environment data in support the clean water program. The result indicated that concentration of elements in well and river water at the Wonosari were still in standard level by Govenor of Daerah Istimewa Yogyakarta no 214/KPTS/1991, were Cd = 0,005 mg/L; Ca = 200 mg/L; Fe = 0,5 mg/L; Co = 0,2 mg/L and Cr = 0,050 mg/L. The concentration in water of Cd, Fe, Ca, Co, and Cr were (0.0002-0.006), (16-40), (5-20), (0.0002-0.37) and (0.0003-0.005) mg/L respectively. The result of analysis give the information that these elements concentration were still proper to use for domestic activities. (author)

Concentration of 24 Trace Elements in Human Heart Tissue Determined by Neutron Activation Analysis

Energy Technology Data Exchange (ETDEWEB)

Wester, P O

1964-06-15

By means of neutron-activation analysis, human heart tissue from autopsy of 20 victims of traumatic accidents has been investigated with respect to the concentration of 24 different trace elements. A recently developed ion-exchange technique combined with gamma spectrometry has been used, which permits simultaneous determination of a large number of trace elements. The following trace elements have been determined quantitatively: Ag, As, Au, Ba, Br; Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Hg, La, Mo, Pt, Rb, Sb, Se, Se, Sm, Zn, W. In some heart samples, Hf and Os were determined qualitatively. The mean and standard deviation are given for the elements Cu, Fe, Se and Zn, Since none of the other quantitatively determined trace elements were normally distributed, the median is given as the central value. When possible, comparisons with values from other investigations have been made. No marked differences in the trace-element concentrations with age or sex could be detected.

Concentration of 24 Trace Elements in Human Heart Tissue Determined by Neutron Activation Analysis

International Nuclear Information System (INIS)

Wester, P.O.

1964-06-01

By means of neutron-activation analysis, human heart tissue from autopsy of 20 victims of traumatic accidents has been investigated with respect to the concentration of 24 different trace elements. A recently developed ion-exchange technique combined with gamma spectrometry has been used, which permits simultaneous determination of a large number of trace elements. The following trace elements have been determined quantitatively: Ag, As, Au, Ba, Br; Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Hg, La, Mo, Pt, Rb, Sb, Se, Se, Sm, Zn, W. In some heart samples, Hf and Os were determined qualitatively. The mean and standard deviation are given for the elements Cu, Fe, Se and Zn, Since none of the other quantitatively determined trace elements were normally distributed, the median is given as the central value. When possible, comparisons with values from other investigations have been made. No marked differences in the trace-element concentrations with age or sex could be detected

Distribution of trace elements in sediment and soil from river Vardar Basin, Macedonia/Greece.

Science.gov (United States)

Popov, Stanko Ilić; Stafilov, Trajče; Šajn, Robert; Tănăselia, Claudiu

2016-01-01

A systematic study was carried out to investigate the distribution of 59 elements in the sediment and soil samples collected from the river Vardar (Republic of Macedonia and Greece) and its major tributaries. The samples were collected from 28 sampling sites. Analyses were performed by inductively coupled plasma-mass spectrometry. R-mode factor analysis (FA) was used to identify and characterise element associations. Seven associations of elements were determined by the method of multivariate statistics. Every factor (Factors 1-3 and 6 and 7 as geogenic and Factors 4 and 5 as anthropogenic associations of elements) are examined and explained separately. The distribution of various elements showed that there is a presence of anthropogenic elements (Ag, Cd, Cu, Ge, Pb, Sn and Zn) introduced in the river sediments and soils from the mining, metallurgical, industrial and agricultural activities in Vardar River Basin, which covers most of the Republic of Macedonia and Central-northern part of Greece.

Elimination of immunodominant epitopes from multispecific DNA-based vaccines allows induction of CD8 T cells that have a striking antiviral potential

DEFF Research Database (Denmark)

Riedl, Petra; Wieland, Andreas; Lamberth, Kasper

2009-01-01

Immunodominance limits the TCR diversity of specific antiviral CD8 T cell responses elicited by vaccination or infection. To prime multispecific T cell responses, we constructed DNA vaccines that coexpress chimeric, multidomain Ags (with CD8 T cell-defined epitopes of the hepatitis B virus (HBV...... cell immunity by multidomain Ags. The "weak" (i.e., easily suppressed) K(b)/C(93-100)-specific CD8 T cell response was efficiently elicited by a HBV core Ag-encoding vector in 1.4HBV-S(mut) tg mice (that harbor a replicating HBV genome that produces HBV surface, core, and precore Ag in the liver). K......(b)/C(93-100)-specific CD8 T cells accumulated in the liver of vaccinated 1.4HBV-S(mut) transgenic mice where they suppressed HBV replication. Subdominant epitopes in vaccines can hence prime specific CD8 T cell immunity in a tolerogenic milieu that delivers specific antiviral effects to HBV...

Determination of trace elements in seawater by neutron activation analysis and electrochemical separation

International Nuclear Information System (INIS)

Jorstad, K.; Salbu, B.

1980-01-01

The combination of neutron activation analysis and electrolysis at a constant, controlled potential has proved itself to be a useful multielement method for the determination of 28 elements in seawater. After freeze-drying and irradiation, the samples are dissolved and electrolyzed for 1 h. The radioactive species deposited on the mercury cathode allow determination of 14 elements (Ag, As, Au, Cd, Co, Cr, Fe, Ga, Hg, La, Mo, Sb, Se, Zn). Another 14 elements (Ba, Br, Ca, Ce, Cs, Eu, Na, Rb, Sc, Sm, Sr, Th, U, Yb) are quantitatively determined by measuring the activities in the residual solution. To obtain a reproducible electrolysis, radioactive tracers have been used to study the decrease of element concentrations in solution as a function of time of electrolysis, the influence of the initial element concentration on the rate constant k, the effect of cathode material and of the pH in the solution. 4 figures, 4 tables

Annual suspended sediment and trace element fluxes in the Mississippi, Columbia, Colorado, and Rio Grande drainage basins

Science.gov (United States)

Horowitz, A.J.; Elrick, K.A.; Smith, J.J.

2001-01-01

Suspended sediment, sediment-associated, total trace element, phosphorus (P), and total organic carbon (TOC) fluxes were determined for the Mississippi, Columbia, Rio Grande, and Colorado Basins for the study period (the 1996, 1997, and 1998 water years) as part of the US Geological Survey's redesigned National Stream Quality Accounting Network (NASQAN) programme. The majority (??? 70%) of Cu, Zn, Cr, Ni, Ba, P, As, Fe, Mn, and Al are transported in association with suspended sediment; Sr transport seems dominated by the dissolved phase, whereas the transport of Li and TOC seems to be divided equally between both phases. Average dissolved trace element levels are markedly lower than reported during the original NASQAN programme; this seems due to the use of 'clean' sampling, processing, and analytical techniques rather than to improvements in water quality. Partitioning between sediment and water for Ag, Pb, Cd, Cr, Co, V, Be, As, Sb, Hg, and Ti could not be estimated due to a lack of detectable dissolved concentrations in most samples. Elevated suspended sediment-associated Zn levels were detected in the Ohio River Basin and elevated Hg levels were detected in the Tennessee River, the former may affect the mainstem Mississippi River, whereas the latter probably do not. Sediment-associated concentrations of Ag, Cu, Pb, Zn, Cd, Cr, Co, Ba, Mo, Sb, Hg, and Fe are markedly elevated in the upper Columbia Basin, and appear to be detectable (Zn, Cd) as far downstream as the middle of the basin. These elevated concentrations seem to result from mining and/or mining-related activities. Consistently detectable concentrations of dissolved Se were found only in the Colorado River Basin. Calculated average annual suspended sediment fluxes at the mouths of the Mississippi and Rio Grande Basins were below, whereas those for the Columbia and Colorado Basins were above previously published annual values. Downstream suspended sediment-associated and total trace element fluxes

Investigations on the photographic elementary process in AgCl single crystal foils

International Nuclear Information System (INIS)

Schmidt, H.; Haase, G.; Zoergiebel, F.

1977-01-01

The behaviour of the latent image produced by actinic radiation (lambda = 365 nm and lambda = 407 nm) in AgCl monocrystal foils highly doped with Cd and grown and annealed under various conditions was studied by extinction measurements in the near infrared. The photographic elementary process in these highly doped crystals cannot be described satisfactorily by the classical Gurney Mott model. Therefore another model was used based on the creation of anion vacancies and molecular chlorine complexes. The radiation-induced electrons occupy these anion vacancies, and quasimetallic centres are formed. By this model the behaviour of the light-induced latent image can also be described as the nuclear particle track formation in the Cd doped AgCl crystals. (author)

Spatial patterns of some trace elements in four Swedish stream networks

Directory of Open Access Journals (Sweden)

J. Temnerud

2013-03-01

Full Text Available Four river basins in southern Sweden, with catchment sizes from 0.3 to 127 km2 (median 1.9, were sampled in October~2007. The 243 samples were analysed for 26 trace elements (Ag, As, Au, Ba, Be, Bi, Cd, Co, Cr, Cu, Ga, Ge, In, La, Li, Mo, Ni, Pb, Sb, Se, Sn, Tl, Ti, U, V and Zn to identify spatial patterns within drainage networks. The range and median of each element were defined for different stream orders, and relationships to catchment characteristics, including deposition history, were explored. The sampling design made it possible to compare the differences along 40 stream reaches, above and below 53 stream junctions with 107 tributaries and between the 77 inlets and outlets of 36 lakes. The largest concentration differences (at reaches, junctions and lakes were observed for lakes, with outlets usually having lower concentration compared to the inlets for As, Ba, Be, Bi, Cd, Co, Cr, Ga, Ge, Ni, Pb, Sn, Ti, Tl, U, V and Zn. Significantly lower concentrations were observed for Cd and Co when comparing headwaters with downstream sites in each catchment. Common factor analysis (FA revealed that As, Bi, Cr, Ga, Ge, Tl and V co-vary positively with Al, Fe and total organic carbon (TOC and negatively with La, Li and pH. The strong removal of a large number of trace elements when passing through lakes is evident though in the FA, where lake surface coverage plots opposite to many of those elements. Forest volume does not respond in a similar systematic fashion and, surprisingly, the amount of wetland does not relate strongly to either Fe or TOC at any of the rivers. A better understanding of the quantitative removal of organic carbon and iron will aid in understanding trace element fluxes from landscapes rich in organic matter and iron.

Some Chemical Group Separations of Radioactive Trace Elements

Energy Technology Data Exchange (ETDEWEB)

Samsahl, K

1962-06-15

As a pretreatment for gamma spectrometric analysis methods have been developed for the chemical separation of traces of P, Sc, Ge, As, Se, Br, Zr, Nb, Ru, Ag, Cd, Sn, Sb, I, Hf, Ta, Re, Os, Au and Hg into 9 different groups. By combining the present methods with already existing chemical group separation methods for traces of Na, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Rb, Sr, Mo, In, Fe, Cs, Ba, L.a, the rare earths, W and Ir, a complete separation scheme comprising 15 groups of elements has been worked out. The chemical 15-group separation method has been advantageously used in gamma spectrometric routine analysis of biological materials.

Some Chemical Group Separations of Radioactive Trace Elements

International Nuclear Information System (INIS)

Samsahl, K.

1962-06-01

As a pretreatment for gamma spectrometric analysis methods have been developed for the chemical separation of traces of P, Sc, Ge, As, Se, Br, Zr, Nb, Ru, Ag, Cd, Sn, Sb, I, Hf, Ta, Re, Os, Au and Hg into 9 different groups. By combining the present methods with already existing chemical group separation methods for traces of Na, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Rb, Sr, Mo, In, Fe, Cs, Ba, L.a, the rare earths, W and Ir, a complete separation scheme comprising 15 groups of elements has been worked out. The chemical 15-group separation method has been advantageously used in gamma spectrometric routine analysis of biological materials

The effect of Ag layer thickness on the properties of WO{sub 3}/Ag/MoO{sub 3} multilayer films as anode in organic light emitting diodes

Energy Technology Data Exchange (ETDEWEB)

Zadsar, Mehdi, E-mail: mehdi_zadsar@yahoo.com [Physics Department, University of Isfahan, Isfahan (Iran, Islamic Republic of); Fallah, Hamid Reza; Mahmoodzadeh, Morteza Haji [Physics Department, University of Isfahan, Isfahan (Iran, Islamic Republic of); Quantum Optics Research Group, University of Isfahan, Isfahan (Iran, Islamic Republic of); Tabatabaei, Seyed Vahid [Physics Department, University of Isfahan, Isfahan (Iran, Islamic Republic of)

2012-04-15

Transparent conductive WO{sub 3}/Ag/MoO{sub 3} (WAM) multilayer electrodes were fabricated by thermal evaporation and the effects of Ag layer thickness on the optoelectronic and structural properties of multilayer electrode as anode in organic light emitting diodes (OLEDs) were investigated using different analytical methods. For Ag layers with thickness varying between 5 and 20 nm, the best WAM performances, high optical transmittance (81.7%, at around 550 nm), and low electrical sheet resistance (9.75 {Omega}/cm{sup 2}) were obtained for 15 nm thickness. Also, the WAM structure with 15 nm of Ag layer thickness has a very smooth surface with an RMS roughness of 0.37 nm, which is suitable for use as transparent conductive anode in OLEDs. The current density-voltage-luminance (J-V-L) characteristics measurement shows that the current density of WAM/PEDOT:PSS/TPD/Alq{sub 3}/LiF/Al organic diode increases with the increase in thickness of Ag and WO{sub 3}/Ag (15 nm)/MoO{sub 3} device exhibits a higher luminance intensity at lower voltage than ITO/PEDOT:PSS/TPD/Alq{sub 3}/LiF/Al control device. Furthermore, this device shows the highest power efficiency (0.31 lm/W) and current efficiency (1.2 cd/A) at the current density of 20 mA/cm{sup 2}, which is improved 58% and 41% compared with those of the ITO-based device, respectively. The lifetime of the WO{sub 3}/Ag (15 nm)/MoO{sub 3} device was measured to be 50 h at an initial luminance of 50 cd/m{sup 2}, which is five times longer than 10 h for ITO-based device. - Highlights: Black-Right-Pointing-Pointer Investigation of Ag thickness effect on the properties of WO{sub 3}/Ag/MoO{sub 3} films. Black-Right-Pointing-Pointer Electrical conductivity of multilayer films increases with increasing Ag thickness. Black-Right-Pointing-Pointer Optical transmittance increases by Ag thickness and at 15 nm, reaches 81.7%. Black-Right-Pointing-Pointer Power efficiency of WO{sub 3}/Ag (15 nm)/MoO{sub 3} based devices is higher than that of

The crystal structure of ramdohrite Pb_5.9Fe_0.1Mn_0.1In_0.1Cd_0.2Ag_2.8Sb_10.8S₂₄

DEFF Research Database (Denmark)

Makovicky, Emil; Mumme, William G.; Gable, Robert W.

2013-01-01

The crystal structure of ramdohrite, Pb5.9Fe0.1Mn0.1In0.1Cd0.2Ag2.8Sb10.8S24, from the Chocaya mine, Potosí, Bolivia, determined by Makovicky and Mumme from film data in 1983, was refined from single-crystal diffractometer data to the R value 0.060, based on 5230 reflections [I > 2σ(I)] from...... a twinned crystal. Lattice parameters are a = 8.7348(3), b = 13.0543(4), c = 19.3117(6) Å, and β = 90.179(2)°, space group P21/n. Two bicapped trigonal prismatic sites of lead bridge and unite adjacent (311)PbS slabs. These slabs contain five distinct coordination pyramids of Sb with trapezoidal cross...... sections, a mixed and disordered Sb-Ag-Cd-(Pb) site, refined as 0.39 Sb + 0.61 Ag, a pure Ag site with a very open, irregular tetrahedral coordination, and an octahedral site occupied by Pb. The (311)PbS slabs contain large lone electron pair micelles formed by four distinct antimony sites in alternation...

Spatially conserved regulatory elements identified within human and mouse Cd247 gene using high-throughput sequencing data from the ENCODE project

DEFF Research Database (Denmark)

Pundhir, Sachin; Hannibal, Tine Dahlbæk; Bang-Berthelsen, Claus Heiner

2014-01-01

. In this study, we have utilized the wealth of high-throughput sequencing data produced during the Encyclopedia of DNA Elements (ENCODE) project to identify spatially conserved regulatory elements within the Cd247 gene from human and mouse. We show the presence of two transcription factor binding sites...

Trace elements in two marine fish cultured in fish cages in Fujian province, China

International Nuclear Information System (INIS)

Onsanit, Sarayut; Ke Caihuan; Wang Xinhong; Wang Kejian; Wang Wenxiong

2010-01-01

Two cultured marine fish, the Japanese seabass (Lateolabrax japonicus) and red seabream (Pagrus major) were collected from eight fish cage sites along the coast of Fujian province in China. The concentrations of Ag, As, Cd, Co, Cu, Fe, Mn, Se, and Zn in their muscle, stomach and liver tissue were quantified. The risk of these trace elements to humans through fish consumption was then assessed. The highest concentrations of As, Cd, Se and Zn in fish feed from fish cages were found in Dongshan Station. Moreover, the As levels in the muscles of both species at all sites were generally higher than China's national standard (>1.0 μg/g). Trace element concentrations in two marine fish followed the order of livers > stomachs > muscles. Although the As levels in two marine caged fish exceeded the permissible standards, the estimated daily intake of As did not exceed the reference dose guideline established by US EPA. For other trace elements examined in this study, their concentrations did not exceed the permissible concentrations of the international standards. - As levels in two marine caged fish from China exceeded the permissible standards, whereas the levels of others trace elements did not exceed the permissible concentrations.

Modification of trace metal accumulation in the green mussel Perna viridis by exposure to Ag, Cu, and Zn

International Nuclear Information System (INIS)

Shi Dalin; Wang Wenxiong

2004-01-01

To examine the Cd, Hg, Ag, and Zn accumulation in the green mussel Perna viridis affected by previous exposure to Cu, Ag, or Zn, the dietary metal assimilation efficiency (AE) and the uptake rate from the dissolved phase were quantified. The mussel's filtration rate, metallothionein (MT) concentration, and metal tissue burden as well as the metal subcellular partitioning were also determined to illustrate the potential mechanisms underlying the influences caused by one metal pre-exposure on the bioaccumulation of the other metals. The green mussels were pre-exposed to Cu, Ag, or Zn for different periods (1-5 weeks) and the bioaccumulation of Cd, Hg, Ag, and Zn were concurrently determined. Pre-exposure to the three metals did not result in any significant increase in MT concentration in the green mussels. Ag concentration in the insoluble fraction increased with increasing Ag exposure period and Ag ambient concentration. Our data indicated that Cd assimilation were not influenced by the mussel's pre-exposure to the three metals (Cu, Ag, and Zn), but its dissolved uptake was depressed by Ag and Zn exposure. Although Hg assimilation from food was not affected by the metal pre-exposure, its influx rate from solution was generally inhibited by the exposure to Cu, Ag, and Zn. Ag bioaccumulation was affected the most obviously, in which its AE increased with increasing Ag tissue concentration, and its dissolved uptake decreased with increasing tissue concentrations of Ag and Cu. As an essential metal, Zn bioaccumulation remained relatively stable following the metal pre-exposure, suggesting the regulatory ability of Zn uptake in the mussels. Zn AE was not affected by metal pre-exposure, but its dissolved uptake was depressed by Ag and Zn pre-exposure. All these results indicated that the influences of one metal pre-exposure on the bioaccumulation of other metals were metal-specific due to the differential binding and toxicity of metals to the mussels. Such factors should

Contamination by trace elements at e-waste recycling sites in Bangalore, India.

Science.gov (United States)

Ha, Nguyen Ngoc; Agusa, Tetsuro; Ramu, Karri; Tu, Nguyen Phuc Cam; Murata, Satoko; Bulbule, Keshav A; Parthasaraty, Peethmbaram; Takahashi, Shin; Subramanian, Annamalai; Tanabe, Shinsuke

2009-06-01

The recycling and disposal of electronic waste (e-waste) in developing countries is causing an increasing concern due to its effects on the environment and associated human health risks. To understand the contamination status, we measured trace elements (TEs) in soil, air dust, and human hair collected from e-waste recycling sites (a recycling facility and backyard recycling units) and the reference sites in Bangalore and Chennai in India. Concentrations of Cu, Zn, Ag, Cd, In, Sn, Sb, Hg, Pb, and Bi were higher in soil from e-waste recycling sites compared to reference sites. For Cu, Sb, Hg, and Pb in some soils from e-waste sites, the levels exceeded screening values proposed by US Environmental Protection Agency (EPA). Concentrations of Cr, Mn, Co, Cu, In, Sn, Sb, Tl, Pb and Bi in air from the e-waste recycling facility were relatively higher than the levels in Chennai city. High levels of Cu, Mo, Ag, Cd, In, Sb, Tl, and Pb were observed in hair of male workers from e-waste recycling sites. Our results suggest that e-waste recycling and its disposal may lead to the environmental and human contamination by some TEs. To our knowledge, this is the first study on TE contamination at e-waste recycling sites in Bangalore, India.

Essential trace (Zn, Cu, Mn and toxic (Cd, Pb, Cr elements in the liver of birds from Eastern Poland

Directory of Open Access Journals (Sweden)

Komosa A.

2012-01-01

Full Text Available We have focused our study on the concentrations of essential heavy metals (Zn, Cu and Mn and non-essential trace metals (Pb, Cd and Cr in the livers of birds from Eastern Poland. The largest mean amount of Zn - as much as 279 mg/kg dry mass (d.m. - was found in mute swans. However, only in one of the analysed buzzard specimens the concentration of Zn, found to be 664 mg/kg d.m., exceeded the level indicative of poisoning for this element. Birds specializing in catching rodents accumulated Mn in their livers in a very narrow range of concentrations, around 5.0 mg/kg d.m. on average. The range of mean Mn concentrations (around 6.5 mg/kg d.m. was also found to be narrow for piscivorous birds. The highest mean levels of Pb were found in mute swans (2.7 mg/kg d.m., and the highest levels of Cd (2.0 mg/kg d.m. for rooks. Concentrations of total Cr above detection level were found in 22 specimens (53.7%, and concentration values were highest for rooks. Analyses showed that the concentrations of biogenic elements did not exceed the levels indicative of poisoning (except in one specimen. The study demonstrated that lead shots remain a hazard to water ecosystems. Pb, Cd and Cr levels in the livers of omnivorous and piscivorous species indicate the permanent presence of these elements in the environment and may confirm the thesis about the growing role of electronic waste, including metallic e-waste, in the emission of the total amount of contamination with these elements.

Investigations on the photographic elementary process in AgCl single crystal foils

International Nuclear Information System (INIS)

Schmidt, H.; Haase, G.; Zoergiebel, F.

1976-01-01

The behaviour of the latent image produced by actinic radiation (lambda = 365 mn and lambda = 407 nm) in AgCl-monocrystal foils highly doped with Cd and grown and annealed under various conditions was studied by extinction measurements in the near infrared. The photographic elementary process in these highly doped crystals cannot be described satisfactorily by the classical Gurney Mott model. Therefore another model was used based on the creation of anion vacancies and molecular chlorine complexes. The radiation induced electrons occupy these anion vacancies, and quasimetallic centers are formed. By this model the behaviour of the light induced latent image can as well be described as the nuclear particle track formation in the Cd doped AgCl-crystals. (orig.) [de

Application of neutron activation analysis to biological materials. Pt. 4. Approach to simultaneous determination of trace elements in human eye tissues with non-destructive neutron activation analysis

Energy Technology Data Exchange (ETDEWEB)

Yamaguchi, T; Bando, M; Nakajima, A [Juntendo Univ., Tokyo (Japan). School of Medicine; Terai, M [Tokyo Metropolitan Univ. (Japan). Faculty of Science; Suzuki-Yasumoto, M [National Inst. of Radiological Sciences, Chiba (Japan)

1980-01-01

Fourteen trace elements (short-lived nuclides: Al, Br, Cu, Mn and V; long-lived nuclides: Ag, Au, Cd, Co, Cr, Fe, Sc, Se and Zn) in human eye tissues are determined simultaneously by non-destructive neutron activation analysis. The quantity of Al, Br, Fe, Se and Zn in the eye tissues (about 1 to more than 10 ..mu..g/g dry weight tissue) seems to be higher than that of other trace elements, although the content of each trace element in individual tissue is scattered in a wide range. Conjunctiva, iris (+ciliary body) and choroid (+pigment epithelium) seem to contain larger amount of various trace elements than other eye tissues. From correlation studies it is evident that the relative distribution of 14 trace elements in various eye tissues are similar, and furthermore the content of trace elements in the eye tissues may be correlated in each of the three groups (group A: Cd, Se and Zn; group B: Al, Cr, Fe, Se and V; group C: Al, Au, Fe and Se).

Neem leaf glycoprotein promotes dual generation of central and effector memory CD8(+) T cells against sarcoma antigen vaccine to induce protective anti-tumor immunity.

Science.gov (United States)

Ghosh, Sarbari; Sarkar, Madhurima; Ghosh, Tithi; Guha, Ipsita; Bhuniya, Avishek; Saha, Akata; Dasgupta, Shayani; Barik, Subhasis; Bose, Anamika; Baral, Rathindranath

2016-03-01

We have previously shown that Neem Leaf Glycoprotein (NLGP) mediates sustained tumor protection by activating host immune response. Now we report that adjuvant help from NLGP predominantly generates CD44(+)CD62L(high)CCR7(high) central memory (TCM; in lymph node) and CD44(+)CD62L(low)CCR7(low) effector memory (TEM; in spleen) CD8(+) T cells of Swiss mice after vaccination with sarcoma antigen (SarAg). Generated TCM and TEM participated either to replenish memory cell pool for sustained disease free states or in rapid tumor eradication respectively. TCM generated after SarAg+NLGP vaccination underwent significant proliferation and IL-2 secretion following SarAg re-stimulation. Furthermore, SarAg+NLGP vaccination helps in greater survival of the memory precursor effector cells at the peak of the effector response and their maintenance as mature memory cells, in comparison to single modality treatment. Such response is corroborated with the reduced phosphorylation of FOXO in the cytosol and increased KLF2 in the nucleus associated with enhanced CD62L, CCR7 expression of lymph node-resident CD8(+) T cells. However, spleen-resident CD8(+) T memory cells show superior efficacy for immediate memory-to-effector cell conversion. The data support in all aspects that SarAg+NLGP demonstrate superiority than SarAg vaccination alone that benefits the host by rapid effector functions whenever required, whereas, central-memory cells are thought to replenish the memory cell pool for ultimate sustained disease free survival till 60 days following post-vaccination tumor inoculation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Population health risk via dietary exposure to trace elements (Cu, Zn, Pb, Cd, Hg, and As) in Qiqihar, Northeastern China.

Science.gov (United States)

Luo, Jinming; Meng, Jia; Ye, Yajie; Wang, Yongjie; Bai, Lin

2018-02-01

The estimated daily intakes (EDIs) of six trace elements (Cu, Zn, Pb, Cd, Hg, and As) in vegetables (leafy vegetable, i.e., bok choy, fruit vegetables, i.e., cucumber and tomato, and other categories, i.e., mushroom, kidney bean, and potato), cereals (rice and wheat flour), and meats (pork, mutton, and beef) most commonly consumed by adult inhabitants of Qiqihar, Northeastern China, were determined to assess the health status of local people. The average EDIs of Cu, Zn, Pb, Cd, Hg, and As were with 20.77 μg (kg bw) -1 day -1 of Cu, 288 μg (kg bw) -1 day -1 of Zn, 2.01 μg (kg bw) -1 day -1 of Pb, 0.41 μg (kg bw) -1 day -1 of Cd, 0.01 μg (kg bw) -1 day -1 of Hg, and 0.52 μg (kg bw) -1 day -1 of As, respectively, which are below the daily allowance recommended by FAO/WHO. However, the maximum EDIs of Pb and Cd were 4.56 μg (kg bw) -1 day -1 and 1.68 μg (kg bw) -1 day -1 , respectively, which are above the recommended levels [i.e., 3.58 μg (kg bw) -1 day -1 for Pb and 1.0 μg (kg bw) -1 day -1 for Cd] by FAO/WHO. This finding indicates that the potential health risk induced by daily ingestion of Pb and Cd for the local residents should receive a significant concern. Similarly, we detected elevated Pb and Cd concentrations, i.e., with average of 13.58 and 0.60 mg kg -1 dw, respectively, in the adult scalp hairs. Consumption of rice, potato, bok choy, and wheat flour contributed to 75 and 82% of Pb and Cd daily intake from foodstuffs. Nevertheless, human scalp hair is inappropriate biological material for determination of the nutritional status of trace elements in this region.

Phosphine-free synthesis of high-quality reverse type-I ZnSe/CdSe core with CdS/CdxZn1 - xS/ZnS multishell nanocrystals and their application for detection of human hepatitis B surface antigen

Science.gov (United States)

Shen, Huaibin; Yuan, Hang; Niu, Jin Zhong; Xu, Shasha; Zhou, Changhua; Ma, Lan; Li, Lin Song

2011-09-01

Highly photoluminescent (PL) reverse type-I ZnSe/CdSe nanocrystals (NCs) and ZnSe/CdSe/CdS/CdxZn1 - xS/ZnS core/multishell NCs were successfully synthesized by a phosphine-free method. By this low-cost, 'green' synthesis route, more than 10 g of high-quality ZnSe/CdSe/CdS/CdxZn1 - xS/ZnS NCs were synthesized in a large scale synthesis. After the overgrowth of a CdS/CdxZn1 - xS/ZnS multishell on ZnSe/CdSe cores, the PL quantum yields (QYs) increased from 28% to 75% along with the stability improvement. An amphiphilic oligomer was used as a surface coating agent to conduct a phase transfer experiment, core/multishell NCs were dissolved in water by such surface modification and the QYs were still kept above 70%. The as-prepared water dispersible ZnSe/CdSe/CdS/CdxZn1 - xS/ZnS core/multishell NCs not only have high fluorescence QYs but also are extremely stable in various physiological conditions. Furthermore, a biosensor system (lateral flow immunoassay system, LFIA) for the detection of human hepatitis B surface antigen (HBsAg) was developed by using this water-soluble core/multishell NCs as a fluorescent label and a nitrocellulose filter membrane for lateral flow. The result showed that such ZnSe/CdSe/CdS/CdxZn1 - xS/ZnS core/multishell NCs were excellent fluorescent labels to detect HBsAg. The sensitivity of HBsAg detection could reach as high as 0.05 ng ml - 1.

Elemental analysis of human placenta by neutron irradiation and gamma-ray spectrometry (standard, prompt and fast-neutron)

International Nuclear Information System (INIS)

Ward, N.I.

1987-01-01

Human placental tissue from 100 hospitalized deliveries were analysed for Ag, Al, As, Au, B, Ba, Br, Ca, Cd, Cl, Co, Cr, Cs, Cu, F, Fe, I, Hg, K, La, Mg, Mn, Mo, Na, Ni, Rb, S, Sb, Sc, Se, Sn, Sr, Ti, V, W and Zn using a combination of pre-chemical separation of sodium with hydrated antimony pentoxide and INAA. Boron and Si values were determined using prompt gamma-ray and fast-neutron techniques, respectively. Analysis of NBS-SRM Bovine Liver 1577 and a 'pooled standard' placental tissue for 33 elements showed a good agreement with most coefficients. Only Cd(-) and Zn(+) showed statistically significant correlations with birth weight, gestational age and placental weight. (author) 54 refs.; 3 tables

Elemental analysis by portable Ag and Rh X-ray sources of a Namban type folding screen

Energy Technology Data Exchange (ETDEWEB)

Pessanha, Sofia [Centro de Física Atómica da Universidade de Lisboa, Av. Professor Gama Pinto, 2 1649-003 Lisboa (Portugal); Le Gac, Agnès [Centro de Física Atómica da Universidade de Lisboa, Av. Professor Gama Pinto, 2 1649-003 Lisboa (Portugal); Departamento de Conservação e Restauro, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Quinta da Torre, 2829-516 Caparica (Portugal); Madeira, Teresa Isabel; Guerra, Mauro [Centro de Física Atómica da Universidade de Lisboa, Av. Professor Gama Pinto, 2 1649-003 Lisboa (Portugal); Carvalho, Maria Luisa, E-mail: luisa@cii.fc.ul.pt [Centro de Física Atómica da Universidade de Lisboa, Av. Professor Gama Pinto, 2 1649-003 Lisboa (Portugal)

2013-08-15

This work focuses on the characterization of the materials used in a Japanese Namban type folding screen. Namban is the art style inspired by the arrival of the southern barbarians or Nambanjin to Japan in 1543, and the commercial trade then initiated. Energy dispersive X ray spectrometry (EDXRF) was used and complemented with Raman spectroscopy. The unexpected aspect about this screen concerns the brownish–grey color over which the characters stand instead of the usual golden color obtained by gilding. To better assess the elemental composition of the background and, most importantly, conclude about the presence of precious metals, an X-ray tube with Rh anode was used supporting the results obtained with the Ag one.

Properties and Microstructures of Sn-Ag-Cu-X Lead-Free Solder Joints in Electronic Packaging

Directory of Open Access Journals (Sweden)

Lei Sun

2015-01-01

Full Text Available SnAgCu solder alloys were considered as one of the most popular lead-free solders because of its good reliability and mechanical properties. However, there are also many problems that need to be solved for the SnAgCu solders, such as high melting point and poor wettability. In order to overcome these shortcomings, and further enhance the properties of SnAgCu solders, many researchers choose to add a series of alloying elements (In, Ti, Fe, Zn, Bi, Ni, Sb, Ga, Al, and rare earth and nanoparticles to the SnAgCu solders. In this paper, the work of SnAgCu lead-free solders containing alloying elements and nanoparticles was reviewed, and the effects of alloying elements and nanoparticles on the melting temperature, wettability, mechanical properties, hardness properties, microstructures, intermetallic compounds, and whiskers were discussed.

Establishing a cost-per-result of laboratory-based, reflex Cryptococcal antigenaemia screening (CrAg) in HIV+ patients with CD4 counts less than 100 cells/μl using a Lateral Flow Assay (LFA) at a typical busy CD4 laboratory in South Africa.

Science.gov (United States)

Cassim, Naseem; Schnippel, Kathryn; Coetzee, Lindi Marie; Glencross, Deborah Kim

2017-01-01

Cryptococcal meningitis is a major cause of mortality and morbidity in countries with high HIV prevalence, primarily affecting patients whose CD4 are per-result of laboratory-based reflexed CrAg screening at one pilot CD4 referral laboratory. CD4 test volumes from 2014 were extracted to estimate percentage of CD4 per/year and 21.73 working days per/month. Costing analyses were undertaken using Microsoft Excel and Stata with a provider prospective. The cost-per-result was estimated using a bottom-up method, inclusive of test kits and consumables (reagents), laboratory equipment and technical effort costs. The ZAR/$ exchange of 14.696/$1 was used, where applicable. One-way sensitivity analyses on the cost-per-result were conducted for possible error rates (3%- 8%, reductions or increases in reagent costs as well as test volumes (ranging from -60% to +60%). The pilot CD4 laboratory performed 267000 CD4 tests in 2014; ~ 9.3% (27500) reported CD4per-result of $4.28 was reported, with reagents contributing $3.11 (72.8%), while technical effort and laboratory equipment overheads contributed $1.17 (27.2%) and $0.03 (per-result range of $3.84 to $6.03. A cost-per-result of $4.28 was established in a typical CD4 service laboratory to enable local budgetary cost projections and programmatic cost-effectiveness modelling. Varying reagent costs linked to currency exchange and varying test volumes in different levels of service can lead to varying cost-per-test and technical effort to manage workload, with an inverse relationship of higher costs expected at lower volumes of tests.

Soil pollution with trace elements at selected sites in Romania studied by instrumental neutron activation analysis

International Nuclear Information System (INIS)

Pantelica, A.; Carmo Freitas, M. do; Ene, A.; Steinnes, E.

2013-01-01

Instrumental neutron activation analysis (INAA) was used to determine concentrations of 42 elements in samples of surface soil collected at seven sites polluted from various anthropogenic activities and a control site in a relatively clean area. Elements studied were Ag, Al, As, Au, Ba, Br, Ca, Cd, Ce, Co, Cr, Cs, Eu, Fe, Gd, Hf, Hg, K, La, Lu, Mg, Mn, Mo, Na, Nd, Ni, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, Ti, U, V, W, Yb, Zn, and Zr. The results are compared with data for trace elements atmospheric deposition in lichen transplants from the same sites. The most severe soil contamination was observed at Copsa Mica from non-ferrous metallurgy. Appreciable soil contamination was also indicated at Baia Mare (non-ferrous mining and metallurgy), Deva (coal-fired power plant, cement and building materials industry), Galati (ferrous metallurgy), Magurele and Afumati (general urban pollution), and Oradea (chemical and light industries). In most cases excessive levels of toxic metals in soils matched correspondingly high values in lichen transplants. Compared to Romanian norms, legal upper limits were exceeded for Zn and Cd at Copsa Mica. Also, As and Sb occurred in excessive levels at given sites. (orig.)

Soil pollution with trace elements at selected sites in Romania studied by instrumental neutron activation analysis

Energy Technology Data Exchange (ETDEWEB)

Pantelica, A. [Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH), Magurele, Ilfov County (Romania); Carmo Freitas, M. do [Technological and Nuclear Institute (ITN), Sacavem (Portugal); Ene, A. [Dunarea de Jos Univ. of Galati (Romania). Dept. of Chemistry, Physics and Environment; Steinnes, E. [Norwegian Univ. of Science and Technology, Trondheim (Norway). Dept. of Chemistry

2013-03-01

Instrumental neutron activation analysis (INAA) was used to determine concentrations of 42 elements in samples of surface soil collected at seven sites polluted from various anthropogenic activities and a control site in a relatively clean area. Elements studied were Ag, Al, As, Au, Ba, Br, Ca, Cd, Ce, Co, Cr, Cs, Eu, Fe, Gd, Hf, Hg, K, La, Lu, Mg, Mn, Mo, Na, Nd, Ni, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, Ti, U, V, W, Yb, Zn, and Zr. The results are compared with data for trace elements atmospheric deposition in lichen transplants from the same sites. The most severe soil contamination was observed at Copsa Mica from non-ferrous metallurgy. Appreciable soil contamination was also indicated at Baia Mare (non-ferrous mining and metallurgy), Deva (coal-fired power plant, cement and building materials industry), Galati (ferrous metallurgy), Magurele and Afumati (general urban pollution), and Oradea (chemical and light industries). In most cases excessive levels of toxic metals in soils matched correspondingly high values in lichen transplants. Compared to Romanian norms, legal upper limits were exceeded for Zn and Cd at Copsa Mica. Also, As and Sb occurred in excessive levels at given sites. (orig.)

Neutron activation of 21 elements by means of the Mg+d reaction (Esub(d) 22 Mev)

International Nuclear Information System (INIS)

Zatolokin, B.V.; Krasnov, N.N.; Konstantinov, I.O.; Bolotskikh, V.I.

1981-01-01

For the first time the activation of 21 elements (Mn, Al, Ti, V, Cr, Mg, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Ag, Cd, Sn, Sb, Ta, W and Pb) by neutrons produced as a result of magnesium target irradiation by deuterons at 22 MeV energy is investigated. The reduced exposure dose rates of point samples of 1 g mass at 1 cm distance from a source are presented. The data on variation in time of exposure dose rates of 1 g mass samples irradiated during 100 hours are indicated. In the framework of a two-group approximation the neutron spectrum is estimated by the results of measurement of two threshold detector activity. It is shown that for the first hours after irradiation Mn, Mg, Al, W, Cu and Ta have the highest exposure dose rates, Cr, Pb, Cd and Sn - the lowest. In four days after irradiation Sb, Ta, Co, Ag and Ti have the highest dose rates, Pb, Fe, Cu and Cr - the lowest. The data obtained can be used in constructing separate accelerator units and in fast neutron activation analysis [ru

Irradiation resistance of intravolume shading elements embedded in photomasks used for CD uniformity control by local intra-field transmission attenuation

Science.gov (United States)

Zait, Eitan; Ben-Zvi, Guy; Dmitriev, Vladimir; Oshemkov, Sergey; Pforr, Rainer; Hennig, Mario

2006-05-01

Intra-field CD variation is, besides OPC errors, a main contributor to the total CD variation budget in IC manufacturing. It is caused mainly by mask CD errors. In advanced memory device manufacturing the minimum features are close to the resolution limit resulting in large mask error enhancement factors hence large intra-field CD variations. Consequently tight CD Control (CDC) of the mask features is required, which results in increasing significantly the cost of mask and hence the litho process costs. Alternatively there is a search for such techniques (1) which will allow improving the intrafield CD control for a given moderate mask and scanner imaging performance. Currently a new technique (2) has been proposed which is based on correcting the printed CD by applying shading elements generated in the substrate bulk of the mask by ultrashort pulsed laser exposure. The blank transmittance across a feature is controlled by changing the density of light scattering pixels. The technique has been demonstrated to be very successful in correcting intra-field CD variations caused by the mask and the projection system (2). A key application criterion of this technique in device manufacturing is the stability of the absorbing pixels against DUV light irradiation being applied during mask projection in scanners. This paper describes the procedures and results of such an investigation. To do it with acceptable effort a special experimental setup has been chosen allowing an evaluation within reasonable time. A 193nm excimer laser with pulse duration of 25 ns has been used for blank irradiation. Accumulated dose equivalent to 100,000 300 mm wafer exposures has been applied to Half Tone PSM mask areas with and without CDC shadowing elements. This allows the discrimination of effects appearing in treated and untreated glass regions. Several intensities have been investigated to define an acceptable threshold intensity to avoid glass compaction or generation of color centers in

AgSb(S{sub x}Se{sub 1−x}){sub 2} thin films for solar cell applications

Energy Technology Data Exchange (ETDEWEB)

González, J.O. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66450, México (Mexico); Shaji, S.; Avellaneda, D. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66450, México (Mexico); Universidad Autónoma de Nuevo León-CIIDIT, Apodaca, Nuevo León, México (Mexico); Castillo, A.G.; Roy, T.K. Das [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66450, México (Mexico); and others

2013-05-15

Highlights: ► AgSb(S{sub x}Se{sub 1−x}){sub 2} thin films were formed by heating Na{sub 2}SeSO{sub 3} dipped Sb{sub 2}S{sub 3}/Ag layers. ► S/Se ratio was varied by changing the dipping time in Na{sub 2}SeSO{sub 3} solution. ► Characterized the films using XRD, XPS, SEM, Optical and electrical measurements. ► Band gap engineering of 1−1.1 eV for x = 0.51 and 0.52 respectively. ► PV Glass/FTO/CdS/AgSb(S{sub x}Se{sub 1−x}){sub 2}/C were prepared showing V{sub oc} = 410 mV, J{sub sc} = 5.7 mA/cm{sup 2}. - Abstract: Silver antimony sulfoselenide (AgSb(S{sub x}Se{sub 1−x}){sub 2}) thin films were prepared by heating glass/Sb{sub 2}S{sub 3}/Ag layers after selenization using sodium selenosulphate solution. First, Sb{sub 2}S{sub 3} thin films were deposited on glass substrates from a chemical bath containing SbCl{sub 3} and Na{sub 2}S{sub 2}O{sub 3}. Then Ag thin films were thermally evaporated onto glass/Sb{sub 2}S{sub 3}, followed by selenization by dipping in an acidic solution of Na{sub 2}SeSO{sub 3}. The duration of selenium dipping was varied as 30 min and 2 h. The heating condition was at 350 °C for 1 h in vacuum. Analysis of X-ray diffraction pattern of the thin films formed after heating showed the formation of AgSb(S{sub x}Se{sub 1−x}){sub 2}. Morphology and elemental analysis were done by scanning electron microscopy and energy dispersive X-ray detection. Depth profile of composition of the thin films was performed by X-ray Photoelectron Spectroscopy. The spectral study showed the presence of Ag, Sb, S, and Se, and the corresponding binding energy analysis confirmed the formation of AgSb(S{sub x}Se{sub 1−x}){sub 2}. Photovoltaic structures (PV) were prepared using AgSb(S{sub x}Se{sub 1−x}){sub 2} thin films as absorber and CdS thin films as window layers on FTO coated glass substrates. The PV structures were heated at 60–80 °C in air for 1 h to improve ohmic contact. Analysis of J–V characteristics of the PV structures showed V

CdS nanobubbles and Cd-DMS nanosheets: solvothermal synthesis and formation mechanism.

Science.gov (United States)

Feng, Miao; Zhan, Hongbing

2013-02-01

CdS nanobubbles and Cd-DMS nanosheets have been prepared by a solvothermal method from a solution of Cd2+ in dimethyl sulfoxide in the absence of elemental S. A formation mechanism for the nanobubble morphology arising during the CdS nanocrystal growth has been proposed, based on the results of transmission electron microscopy and photoluminescence spectrophotometry. The correlation of the morphology with reaction time was also suggested, and may be applicable to the solvothermal synthesis of other nanomaterials.

Elemental composition of platelets. Part I. Sampling and sample preparation of platelets for trace-element analysis

International Nuclear Information System (INIS)

Iyengar, G.V.; Borberg, H.; Kasperek, K.; Kiem, J.; Siegers, M.; Feinendegen, L.E.; Gross, R.

1979-01-01

Sampling of platelets for trace-element analysis poses special problems: obtaining adequate sample materials, achieving a sufficient cell purity, preserving viability (integrity), correcting for trapped plasma, and controlling contamination. We used a blood-cell separator for the primary isolation of platelets from blood, and differential centrifugation in natural plasma to further isolate them. The pyrimidopyrimidine RA233 was used as a stabilizer to maintain viability. 131 I-labeled human serum albumin was used to estimate trapped plasma. Contamination was controlled by using five-times-distilled water to simulate donor's blood in the system and by comparing three fractions: the serum, the first portion of the platelet-rich plasma, and the supernatant plasma after the final centrifugation. Neutron activation analysis was used for the elemental analysis. A single differential centrifugation of the platelet-rich plasma from the blood-cell separator at 400 x g for 8 min was optimum (mean mass fractions: erythrocytes/platelets < 5 mg/g and leukocytes/platelets < 20 mg/g). The trapped plasma in the wet platelet samples amounted to about 0.40 g/g. No appreciable contamination from the sampling system was found for the elements Ag, Cd, Co, Cr, Cs, Cu, Fe, Mo, Rb, Sb, Se, and Zn. 2 figures, 3 tables

Heavy metals contamination and their risk assessment around the abandoned base metals and Au-Ag mines in Korea

Science.gov (United States)

Chon, Hyo-Taek

2017-04-01

Heavy metals contamination in the areas of abandoned Au-Ag and base metal mines in Korea was investigated in order to assess the level of metal pollution, and to draw general summaries about the fate of toxic heavy metals in different environments. Efforts have been made to compare the level of heavy metals, chemical forms, and plant uptake of heavy metals in each mine site. In the base-metals mine areas, significant levels of Cd, Cu, Pb and Zn were found in mine dump soils developed over mine waste materials and tailings. Leafy vegetables tend to accumulate heavy metals(in particular, Cd and Zn) higher than other crop plants, and high metal concentrations in rice crops may affect the local residents' health. In the Au-Ag mining areas, arsenic would be the most characteristic contaminant in the nearby environment. Arsenic and heavy metals were found to be mainly associated with sulfide gangue minerals, and the mobility of these metals would be enhanced by the effect of continuing weathering and oxidation. According to the sequential extraction of metals in soils, most heavy metals were identified as non-residual chemical forms, and those are very susceptible to the change of ambient conditions of a nearby environment. The concept of pollution index(PI) of soils gives important information on the extent and degree of multi-element contamination, and can be applied to the evaluation of mine soils before their agricultural use and remediation. The risk assessment process comprising exposure assessment, dose-response assessment, and risk characterization was discussed, and the results of non-cancer risk of As, Cd, and Zn, and those of cancer risk of As were suggested.

Correlation of Element Concentration of Cd, Cr, Co and Sc in Sea Water, Fish and Algae Samples from Beach of Lemahabang Muria

International Nuclear Information System (INIS)

Sukirno; Rosidi; Agus Taftazani

2007-01-01

The analysis of Cd, Cr, Co, Sb and Sc element in beach environmental samples Lemahabang Muria in the year 2004 has been carried out by using neutron activation analysis (NAA) method. All of heavy metals from sea water (2.0 μg/l) are obviously lower than the threshold value established by SKRI No 51/2004. From the observed data by Excel application of the correlation value (r) shows that between Cd, Cr, Co, Sb and Sc concentrations from dependent variable of sea water about tree independent variable of kerapu fish, green and brown algae shows a highly positive significant correlation (r > 0.92) except element of Sb was sufficiently positive high (r = 0.66). (author)

Genome-Based In Silico Identification of New Mycobacterium tuberculosis Antigens Activating Polyfunctional CD8+ T Cells in Human Tuberculosis

DEFF Research Database (Denmark)

Tang, Sheila Tuyet; van Meijgaarden, Krista E.; Caccamo, Nadia

2011-01-01

8(+) T cell proliferation assays (CFSE dilution) in 41 M. tuberculosis-responsive donors identified 70 new M. tuberculosis epitopes. Using HLA/peptide tetramers for the 18 most prominently recognized HLA-A*0201-binding M. tuberculosis peptides, recognition by cured TB patients' CD8(+) T cells......-epitope/Ag repertoire for human CD8(+) T cells is much broader than hitherto suspected, and the newly identified M. tuberculosis Ags are recognized by (poly) functional CD8(+) T cells during control of infection. These results impact on TB-vaccine design and biomarker identification. The Journal of Immunology, 2011...

Concentrations of radionuclides and selected stable elements in fruits and vegetables

International Nuclear Information System (INIS)

Oakes, T.W.; Shank, K.E.

1977-01-01

Twenty-two types of fruits and vegetables collected from two commercial supermarkets have been analyzed for their radionuclidic and stable-element composition. A specific gamma-emitting isotope analysis was performed on each sample for 40 K, 60 Co, 95 Zr-Nb, 106 Ru, 137 Cs, 226 Ra, and 232 Th. The concentration of the stable elements in each sample were determined using multi-element neutron-activation analysis (Al, Ag, Au, As, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Cu, Eu, Fe, Hf, I, K, La, Mn, Mo, Mg, Na, Rb, Sb, Sc, Se, Sr, Ta, Te, Th, Ti, Zn, Zr) and atomic absorption (Cd, Ni, Pb). Information on the composition of a typical diet is used to estimate the radiological dose to man subsequent to ingestion of these fruits and vegetables. The stable-elemental compositions of the foodstuffs analyzed were compared with estimated values assuming foliar deposition and long-term buildup of effluents from a large modern coal-fired steam plant. It is tentatively concluded that for the general case of a precipitator-equipped, coal-fired steam plant, no toxic levels of trace elements in foodstuffs are expected as a result of the plant operation

Backscattering of 59.54 keV photons for characterization of metallic elements

International Nuclear Information System (INIS)

Elyaseery, I.S.; Chong Chon Sing; Ahmad Shukri Mustapa Kamal; Abdul Aziz Tajuddin

2000-01-01

Scattering measurements of x-rays and gamma rays have been developed for the characterization of internal features of materials such as density or composition. Previous studies were generally carried at small scattering angles. In this paper, a system is described for preliminary studies of back scattering of photons for characterization of materials. The apparatus consist of an annular 100 mCi 241 Am source and a high purity thin intensities for the 59.54 keV photons are presented for different metallic elements such as Al, Cu, Zn, Zr, Nb, Mo, Ag, Cd, In, Sn, Ta and W. The measurements were carried out at back scattering angles of 145 0 , 154 0 , 165 0 . Coherent peak measurements offer greater sensitivity than Compton peak measurements. In particular, the 59.54 keV coherent peak intensity shows a proportional increase with increasing Z number elements except for the elements Ta and W whose absorption edges are in the vicinity of this photon energy. The experimental results demonstrate the feasibility of the backscattering method for the characterization of metallic elements. (Author)

First results of total and partial cross-section measurements of the 107Ag(p,γ)108Cd reaction

Science.gov (United States)

Heim, Felix; Mayer, Jan; Scholz, Philipp; Spieker, Mark; Zilges, Andreas

2018-01-01

The γ process is assumed to play an important role in the nucleosynthesis of the majority of the p nuclei. Since the network of the γ process includes so many different reactions and - mainly unstable - nuclei, cross-section values are predominantly calculated in the scope of the Hauser-Feshbach statistical model. The values heavily depend on the nuclear-physics input parameters. The results of total and partial cross-section measurements are used to improve the accuracy of the theoretical calculations. In order to extend the experimental database, the 107Ag(p,γ)108Cd reaction was studied via the in-beam method at the high-efficiency HPGe γ-ray spectrometer HORUS at the University of Cologne. Proton beams with energies between 3.5 MeV and 5.0 MeV were provided by the 10 MV FN-Tandem accelerator leading to the determination of four new total cross-section values. After slight adjustments of the nuclear level density and γ-ray strength function an excellent agreement between theoretical calculations and experimentally deduced values for both total and partial cross sections has been obtained.

Anomalous growth of Ba on Ag(111)

International Nuclear Information System (INIS)

Teodoro, O.M.N.D.; Los, J.; Moutinho, A.M.C.

2002-01-01

Electropositive elements are often adsorbed on metals to produce a well-known decrease in the surface work function. During deposition, the work function drops steeply and reaches a minimum at coverage lower than one monolayer. Then, it increases slightly and the work function converges to the value of the deposited element. In this work, we report anomalous behavior found during the deposition of barium on a Ag(111) surface. After a minimum of about 2.4 eV the work function did not increase up to 2.7 eV, the bulk barium work function, no matter what amount of barium was deposited. Auger electron spectroscopy corroborated these results in which we measured a permanent and constant intensity of the Ag MNN peak for high barium coverage. To explain this anomalous growth of barium on Ag(111) we propose an explanation based on the diffusion of silver atoms into the barium film. Further experiments showed that coadsorption of oxygen before a second deposition of barium blocked the diffusion thus allowing the work function to reach 2.7 eV

Element enrichment and U-series isotopic characteristics of the hydrothermal sulfides at Jade site in the Okinawa Trough

Institute of Scientific and Technical Information of China (English)

无

2009-01-01

The geochemical and U-series isotopic characteristics of hydrothermal sulfide samples from the Jade site (127°04.5′E, 27°15′N, water depth 1300-1450 m) at Jade site in the Okinawa Trough were analyzed. In the hydrothermal sulfide samples bearing sulfate (samples HOK1 and HOK2), the LREEs are relatively enriched. All the hydrothermal sulfide samples except HOK1 belong to Zn-rich hydrothermal sulfide. In comparison with Zn-rich hydrothermal sulfides from other fields, the contents of Zn, Pb, Ag, Cd, Au and Hg are higher, the contents of Fe, Al, Cr, Co, Ni, Sr, Te, Cs, Ti and U lower, and the 210Pb radioactivity ratios and 210Pb/Pb ratios very low. In the hydrothermal sulfide mainly composed of sphalerite, the correlations between rare elements Hf and U, and Hf and Mn as well as that between dispersive elements Ga and Zn, are strongly positive; also the contents of Au and Ag are related to Fe-sulfide, because the low temperature promotes enrichment of Au and Ag. Meanwhile, the positive correlations between Fe and Bi and between Zn and Cd are not affected by the change of mineral assemblage. Based on the 210Pb/Pb ratios of hydrothermal sulfide samples (3.99×10-5-5.42×10?5), their U isotopic composition (238U content 1.15-2.53 ppm, 238U activity 1.07-1.87 dpm/g, 234U activity 1.15-2.09 dpm/g and 234U/238U ratio 1.07-1.14) and their 232Th and 230Th contents are at base level, and the chronological age of hydrothermal sulfide at Jade site in the Okinawa Trough is between 200 and 2000 yr.

Size effect for phase stability on Au–Cd–Ag of phase boundary composition

International Nuclear Information System (INIS)

Matsuoka, Yuki; Suzuki, Keiko; Kudo, Natsuko

2013-01-01

Highlights: ► Size and heat treatment effects of phase boundary composition Au 52.5−x Cd 47.5 Ag x were studied. ► The transformation temperature T 0 increases by quench. It is investigated that disordering of atoms and lattice defects make β-phase unstable. ► Downsizing sample decreased T 0 in β-phase, showed a tendency of increase in coexistent phase. ► Downsizing is supposed to make difficult nucleation for martensitic transformation. ► Increasing of surface ratio by downsizing of powder sample is estimated to make easy to transform from unstable β-phase to martensite phase. -- Abstract: Size and heat treatment effects on martensitic transformation of phase boundary composition Au 52.5−x Cd 47.5 Ag x were studied. Au 52.5−x Cd 47.5 Ag x has coexistent phase of β-phase and α-phase of fcc structure at x > 42 at.%. The transformation temperature T 0 decreases as Au is substituted on Ag over phase boundary. T 0 increases by quench in both case of bulk and powder. This behavior is investigated that disordering of atoms and lattice defects make β-phase (L2 1 , B2 or bcc) unstable. Size effect was also inspected. Downsizing sample decreased the transformation temperature in β-phase. On the contrary, the transformation temperature of the coexistent phase showed a tendency of increase. Downsizing is supposed to make difficult nucleation for martensitic transformation because of reduction of β-phase ordered volume. Increasing of surface (disorder structure) ratio by downsizing of powder sample is estimated to make easy to transform from unstable β-phase to martensite phase

Major and trace elements in Sphagnum moss from four southern German bogs, and comparison with available moss monitoring data

OpenAIRE

KEMPTER HEIKE; KRACHLER MICHAEL; SHOTYK W.; ZACCONE CLAUDIO

2017-01-01

In this paper, we present concentrations of an array of major and trace elements (Ag, Al, As, Ba, Bi, Cd, Co, Cr, Cu, Fe, Mn, Mo, Rb, Sb, Sc, Sr, Th, Tl, U, V, Zn) in living Sphagnum mosses from four southern German bogs and compare them with moss monitoring data of the respective regions. To do this, Sphagnum mosses were collected in Upper Bavaria (Oberbayern, OB) and the Northern Black Forest (Nordschwarzwald, NBF). Surfaces of Sphagnum carpets were marked with plastic mesh and, one year la...

Increased numbers of preexisting memory CD8 T cells and decreased T-bet expression can restrain terminal differentiation of secondary effector and memory CD8 T cells.

Science.gov (United States)

Joshi, Nikhil S; Cui, Weiguo; Dominguez, Claudia X; Chen, Jonathan H; Hand, Timothy W; Kaech, Susan M

2011-10-15

Memory CD8 T cells acquire effector memory cell properties after reinfection and may reach terminally differentiated, senescent states ("Hayflick limit") after multiple infections. The signals controlling this process are not well understood, but we found that the degree of secondary effector and memory CD8 T cell differentiation was intimately linked to the amount of T-bet expressed upon reactivation and preexisting memory CD8 T cell number (i.e., primary memory CD8 T cell precursor frequency) present during secondary infection. Compared with naive cells, memory CD8 T cells were predisposed toward terminal effector (TE) cell differentiation because they could immediately respond to IL-12 and induce T-bet, even in the absence of Ag. TE cell formation after secondary (2°) or tertiary infections was dependent on increased T-bet expression because T-bet(+/-) cells were resistant to these phenotypic changes. Larger numbers of preexisting memory CD8 T cells limited the duration of 2° infection and the amount of IL-12 produced, and consequently, this reduced T-bet expression and the proportion of 2° TE CD8 T cells that formed. Together, these data show that over repeated infections, memory CD8 T cell quality and proliferative fitness is not strictly determined by the number of serial encounters with Ag or cell divisions, but is a function of the CD8 T cell differentiation state, which is genetically controlled in a T-bet-dependent manner. This differentiation state can be modulated by preexisting memory CD8 T cell number and the intensity of inflammation during reinfection. These results have important implications for vaccinations involving prime-boost strategies.

Heavy ion acceleration at the AGS

International Nuclear Information System (INIS)

Lee, Y.Y.

1989-01-01

The Brookhaven AGS is alternating gradient synchrotron, 807 meters in circumference, which was originally designed for only protons. Using the 15 MV Brookhaven Tandem Van de Graaff as an injector, the AGS started to accelerate heavy ions of mass lighter than sulfur. Because of the relatively poor vacuum (∼10 -8 Torr), the AGS is not able to accelerate heavier ions which could not be fully stripped of electrons at the Tandem energy. When the AGS Booster, which is under construction, is completed the operation will be extended to all species of heavy ions including gold and uranium. Because ultra-high vacuum (∼10 -11 Torr) is planned, the Booster can accelerate partially stripped elements. The operational experience, the parameters, and scheme of heavy ion acceleration will be presented in detail from injection to extraction, as well as future injection into the new Relativistic Heavy Ion Collider (RHIC). A future plan to improve intensity of the accelerator will also be presented. 5 figs., 4 tabs

Sn-In-Ag phase equilibria and Sn-In-(Ag)/Ag interfacial reactions

International Nuclear Information System (INIS)

Chen Sinnwen; Lee Wanyu; Hsu Chiaming; Yang Chingfeng; Hsu Hsinyun; Wu Hsinjay

2011-01-01

Research highlights: → Thermodynamic models of Sn-In and Sn-In-Ag are developed using the CALPHAD approach. → Reaction layer in the Sn-In-(Ag)/Ag couples at 100 deg. C is thinner than those at 25 deg. C, 50 deg. C, and 75 deg. C. → Reactions in the Sn-20 wt%In-2.8 wt%Ag/Ag couples are faster than those in the Sn-20 wt%In/Ag couples. - Abstract: Experimental verifications of the Sn-In and Sn-In-Ag phase equilibria have been conducted. The experimental measurements of phase equilibria and thermodynamic properties are used for thermodynamic modeling by the CALPHAD approach. The calculated results are in good agreement with experimental results. Interfacial reactions in the Sn-In-(Ag)/Ag couples have been examined. Both Ag 2 In and AgIn 2 phases are formed in the Sn-51.0 wt%In/Ag couples reacted at 100 and 150 deg. C, and only the Ag 2 In phase is formed when reacted at 25, 50 and 75 deg. C. Due to the different growth rates of different reaction phases, the reaction layer at 100 deg. C is thinner than those at 25 deg. C, 50 deg. C, and 75 deg. C. In the Sn-20.0 wt%In/Ag couples, the ζ phase is formed at 250 deg. C and ζ/AgIn 2 phases are formed at 125 deg. C. Compared with the Sn-20 wt%In/Ag couples, faster interfacial reactions are observed in the Sn-20.0 wt%In-2.8 wt%Ag/Ag couples, and minor Ag addition to Sn-20 wt%In solder increases the growth rates of the reaction phases.

2B4-SAP signaling is required for the priming of naive CD8+ T cells by antigen-expressing B cells and B lymphoma cells.

Science.gov (United States)

Huang, Yu-Hsuan; Tsai, Kevin; Tan, Sara Y; Kang, Sohyeong; Ford, Mandy L; Harder, Kenneth W; Priatel, John J

2017-01-01

Mutations in SH2D1A gene that encodes SAP (SLAM-associated protein) result in X-linked lymphoproliferative disease (XLP), a rare primary immunodeficiency disease defined by exquisite sensitivity to the B-lymphotropic Epstein-Barr virus (EBV) and B cell lymphomas. However, the precise mechanism of how the loss of SAP function contributes to extreme vulnerability to EBV and the development of B cell lymphomas remains unclear. Here, we investigate the hypothesis that SAP is critical for CD8 + T cell immune surveillance of antigen (Ag)-expressing B cells or B lymphoma cells under conditions of defined T cell receptor (TCR) signaling. Sh2d1a - / - CD8 + T cells exhibited greatly diminished proliferation relative to wild type when Ag-presenting-B cells or -B lymphoma cells served as the primary Ag-presenting cell (APC). By contrast, Sh2d1a - / - CD8 + T cells responded equivalently to wild-type CD8 + T cells when B cell-depleted splenocytes, melanoma cells or breast carcinoma cells performed Ag presentation. Through application of signaling lymphocyte activation molecule (SLAM) family receptor blocking antibodies or SLAM family receptor-deficient CD8 + T cells and APCs, we found that CD48 engagement on the B cell surface by 2B4 is crucial for initiating SAP-dependent signaling required for the Ag-driven CD8 + T cell proliferation and differentiation. Altogether, a pivotal role for SAP in promoting the expansion and differentiation of B cell-primed viral-specific naive CD8 + T cells may explain the selective immune deficiency of XLP patients to EBV and B cell lymphomas.

2B4-SAP signaling is required for the priming of naive CD8+ T cells by antigen-expressing B cells and B lymphoma cells

Science.gov (United States)

2017-01-01

ABSTRACT Mutations in SH2D1A gene that encodes SAP (SLAM-associated protein) result in X-linked lymphoproliferative disease (XLP), a rare primary immunodeficiency disease defined by exquisite sensitivity to the B-lymphotropic Epstein–Barr virus (EBV) and B cell lymphomas. However, the precise mechanism of how the loss of SAP function contributes to extreme vulnerability to EBV and the development of B cell lymphomas remains unclear. Here, we investigate the hypothesis that SAP is critical for CD8+ T cell immune surveillance of antigen (Ag)-expressing B cells or B lymphoma cells under conditions of defined T cell receptor (TCR) signaling. Sh2d1a−/− CD8+ T cells exhibited greatly diminished proliferation relative to wild type when Ag-presenting-B cells or -B lymphoma cells served as the primary Ag-presenting cell (APC). By contrast, Sh2d1a−/− CD8+ T cells responded equivalently to wild-type CD8+ T cells when B cell-depleted splenocytes, melanoma cells or breast carcinoma cells performed Ag presentation. Through application of signaling lymphocyte activation molecule (SLAM) family receptor blocking antibodies or SLAM family receptor-deficient CD8+ T cells and APCs, we found that CD48 engagement on the B cell surface by 2B4 is crucial for initiating SAP-dependent signaling required for the Ag-driven CD8+ T cell proliferation and differentiation. Altogether, a pivotal role for SAP in promoting the expansion and differentiation of B cell-primed viral-specific naive CD8+ T cells may explain the selective immune deficiency of XLP patients to EBV and B cell lymphomas. PMID:28344876

Metal dispersion and mobility in soils from the Lik Zn-Pb-Ag massive sulphide deposit, NW Alaska: Environmental and exploration implications

Science.gov (United States)

Kelley, K.D.; Kelley, D.L.

2003-01-01

The Lik deposit in northern Alaska is a largely unexposed shale-hosted Zn-Pb-Ag massive sulphide deposit that is underlain by continuous permafrost. Residual soils overlying the mineralized zone have element enrichments that are two to six times greater than baseline values. The most prominent elements are Ag, Mo, P, Se, Sr, V by total 4-acid digestion and Tl by a weak partial digestion (Enzyme Leach or EL) because they show multi-point anomalies that extend across the entire mineralized zone, concentration ranges are 0.5-2.6 ppm Ag, 4-26 ppm Mo, 0.1-0.3% P, 3-22 ppm Se, 90-230 ppm Sr, 170-406 ppm V, and 1.6-30 ppb Tl. Lead, Sb, and Hg are also anomalous (up to 178 ppm, 30 ppm, and 1.9 ppm, respectively), but all are characterized by single point anomalies directly over the mineralized zone, with only slightly elevated concentrations over the lower mineralized section. Zinc (total) has a consistent baseline response of 200 ppm, but it is not elevated in soils overlying the mineralized zone. However, Zn by EL shows a distinct single-point anomaly over the ore zone that suggests it was highly mobile and partly adsorbed on oxides or other secondary phases during weathering. In situ analyses (by laser ablation ICP-MS) of pyrite and sphalerite from drill core suggest that sphalerite is the primary residence for Ag, Cd, and Hg in addition to Zn, and pyrite contains As, Fe, Sb, and Tl. The level and degree of oxidation, and the proportion of reacting pyrite and carbonate minerals are two factors that affected the mobility and transport of metals. In oxidizing conditions, Zn is highly mobile relative to Hg and Ag, perhaps explaining the decoupling of Zn from the other sphalerite-hosted elements in the soils. Soils are acidic (to 3.9 pH) directly over the deposit due to the presence of acid-producing pyrite, but acid-neutralizing carbonate away from the mineralized zone yield soils that are near neutral. The soils therefore formed in a complex system involving oxidation and

Colorimetric detection of Cd"2"+ using 1-amino-2-naphthol-4-sulfonic acid functionalized silver nanoparticles

International Nuclear Information System (INIS)

Huang, Pengcheng; Liu, Bowen; Jin, Weiwei; Wu, Fangying; Wan, Yiqun

2016-01-01

A colorimetric assay has been developed for facile, rapid, and sensitive detection of Cd"2"+ using 1-amino-2-naphthol-4-sulfonic acid functionalized silver nanoparticles (ANS-AgNPs). The presence of Cd"2"+ induces the aggregation of ANS-AgNPs through cooperative metal–ligand interaction. As a result, the characteristic surface plasmon resonance (SPR) peak of ANS-AgNPs at 390 nm was red-shifted to 580 nm, yielding a color change from bright yellow to reddish-brown. The color change is monitored by UV–Vis spectrometer and can be directly read out by the naked eye. Under the optimized conditions, a good linear relationship (correlation coefficient R = 0.997) was obtained between the ratio of the absorbance at 580 nm to that at 390 nm (A_5_8_0_n_m/A_3_9_0_n_m) and the concentration of Cd"2"+ over the range of 1.0–10 μM with detection limit of 87 nM. The proposed method is simple and efficient, which has been applied for determining Cd"2"+ in milk powder, serum, and lake water with satisfactory results.

Survey of trace elements (Al, As, Cd, Cr, Co, Hg, Mn, Ni, Pb, Se, and Si) in retail samples of flavoured and bottled waters.

Science.gov (United States)

Barroso, M F; Ramos, S; Oliva-Teles, M T; Delerue-Matos, C; Sales, M G F; Oliveira, M B P P

2009-01-01

Concentrations of eleven trace elements (Al, As, Cd, Cr, Co, Hg, Mn, Ni, Pb, Se, and Si) were measured in 39 (natural and flavoured) water samples. Determinations were performed using graphite furnace electrothermetry for almost all elements (Al, As, Cd, Cr, Co, Mn, Ni, Pb, and Si). For Se determination hydride generation was used, and cold vapour generation for Hg. These techniques were coupled to atomic absorption spectrophotometry. The trace element content of still or sparkling natural waters changed from brand to brand. Significant differences between natural still and natural sparkling waters (p element was compared with the presence of flavours, preservatives, acidifying agents, fruit juice and/or sweeteners, according to the labelled composition. It was shown that flavoured waters generally increase the trace element content. The addition of preservatives and acidifying regulators had a significant influence on Mn, Co, As and Si contents (p < 0.05). Fruit juice can also be correlated to the increase of Co and As. Sweeteners did not provide any significant difference in Mn, Co, Se and Si content.

Content of Chemical Elements in Wood-Destroying Fungi

Directory of Open Access Journals (Sweden)

Strapáč I.

2016-12-01

Full Text Available The aim of this study was to examine the content of chemical elements in the dried fruiting bodies of edible wood decaying fungi such as Honey mushrooms (Armillaria mellea, Shiitakes (Lentinus edodes and Oyster mushrooms (Pleurotus ostreatus. Powdered samples of fungi were mineralized in a microwave digestion. Twenty-one (21 chemical elements were detected in the plasma of the device ICP-MS AGILENT 7500c by accredited methods with the aid of calibration curves. The content of individual elements varied within a considerable range. The highest contents of K, Mn, Cu and Cd were found in the fruiting bodies of Honey mushrooms (Armillaria mellea. Shiitakes (Lentinus edodes had the highest content of B and Mo. Significant differences were found in the content of elements in the Oyster mushrooms (Pleurotus ostreatus from Slovakia, Hungary and China. The highest content of Al was found in the Oyster mushrooms (Pleurotus ostreatus from Hungary. The Chinese oysters had a maximum contents of Ca, Mg, Co, Pb, As and U. The Oyster mushrooms (Pleurotus ostreatus from Lemešany (Slovakia had the highest contents of Na, Zn, Fe, Se, Ag, Hg and Cr. The difference of chemical element content could be influenced by the genotype of the fungus and by the composition of substrate on which mushroom grow up.

Solution-processed efficient CdTe nanocrystal/CBD-CdS hetero-junction solar cells with ZnO interlayer

International Nuclear Information System (INIS)

Tian, Yiyao; Zhang, Yijie; Lin, Yizhao; Gao, Kuo; Zhang, Yunpeng; Liu, Kaiyi; Yang, Qianqian; Zhou, Xiao; Qin, Donghuan; Wu, Hongbin; Xia, Yuxin; Hou, Lintao; Lan, Linfeng; Chen, Junwu; Wang, Dan; Yao, Rihui

2013-01-01

CdTe nanocrystal (NC)/CdS p–n hetero-junction solar cells with an ITO/ZnO-In/CdS/CdTe/MoO x /Ag-inverted structure were prepared by using a layer-by-layer solution process. The CdS thin films were prepared by chemical bath deposition on top of ITO/ZnO-In and were found to be very compact and pin-hole free in a large area, which insured high quality CdTe NCs thin-film formation upon it. The device performance was strongly related to the CdCl 2 annealing temperature and annealing time. Devices exhibited power conversion efficiency (PCE) of 3.08 % following 400 °C CdCl 2 annealing for 5 min, which was a good efficiency for solution processed CdTe/CdS NC-inverted solar cells. By carefully designing and optimizing the CdCl 2 -annealing conditions (370 °C CdCl 2 annealing for about 15 min), the PCE of such devices showed a 21 % increase, in comparison to 400 °C CdCl 2 -annealing conditions, and reached a better PCE of 3.73 % while keeping a relatively high V OC of 0.49 V. This PCE value, to the best of our knowledge, is the highest PCE reported for solution processed CdTe–CdS NC solar cells. Moreover, the inverted solar cell device was very stable when kept under ambient conditions, less than 4 % degradation was observed in PCE after 40 days storage

Relationship between Microstructure and Properties of Cu-Cr-Ag-(Ce) Alloy Using Microscopic Investigation.

Science.gov (United States)

Chen, Huiming; Yuan, Dawei; Wu, Shanjiang; Wang, Hang; Xie, Weibin; Yang, Bin

2017-01-01

Microstructure, precipitation hardening response, and mechanical and physical properties of Cu-Cr-Ag alloy and Cu-Cr-Ag-Ce alloy have been investigated using transmission electron microscopy, scanning electron microscope, optical microscope, electrical conductivity analysis, and tensile test. The influence of element Ce on the matrix refinement, impurity removal, and precipitation in the Cu-Cr-Ag alloys has been analyzed. The experimental results show that the strength and electrical conductivity of Ce containing alloys are greater than those of Ce-free alloys after each processing step. Improvement of strength and electrical conductivity of the Cu-Cr-Ag alloy by adding Ce element is attributed to removing oxygen and sulfur from as-cast alloy.

Spatially resolved element analysis of historical violin varnishes by use of muPIXE.

Science.gov (United States)

von Bohlen, Alex; Röhrs, Stefan; Salomon, Joseph

2007-02-01

External muPIXE has been used for characterisation of small samples of varnish from historical violins, and pieces of varnished wood from historical and modern stringed instruments. To obtain spatially resolved information about the distribution of elements across the varnish layers single-spot analysis, line-scans, and area-mapping were performed. Local resolution of approximately 20 mum was obtained from the 3 MeV, 1 nA proton micro-probe. Results from simultaneous multi-element determination of Na, Mg, Al, Si, P, S, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Br, Rb, Sr, Ag, Cd, Sn, Ba, and Pb in historical varnishes are presented. Semi-quantitative evaluation of line-scans recorded on diverse historical varnishes is reported. The applied method is discussed in detail and the results obtained are critically reviewed and compared with those in the literature.

Elemental data on human hair sampled from Indian student population and their interpretation for studies in environmental exposure

International Nuclear Information System (INIS)

Arunachalam, J.; Gangadharan, S.; Yegnasubramanian, S.

1979-01-01

The head hair samples from 260 students distributed over the country have been analysed by instrumental neutron activation analysis using high-resolution gamma-ray spectrometry through a combination of short and long irradiations. The elemental abundances for 21 elements (Na, Cl, K, Sc, Cr, Mn, Fe, Co, Cu, Zn, As, Se, Br, Rb, Ag, Cd, Sb, I, La, Ce and Au) computed using a secondary standard, developed in this laboratory, as a comparator are presented and compared with some of the published data. The elemental concentration data have been analysed to look for statistically significant differences between groups based on sex, diet, geographical location, section of hair, etc., and the trace element features have been processed through pattern recognition approach using principal components analysis and minimal spanning tree. The vegetarians and non-vegetarians form clearly distinct groups, while the clusters for general population seem to be based on geographical location. (author)

Trace Elements in Human Myocardial Infarction Determined by Neutron Activation Analysis

International Nuclear Information System (INIS)

Wester, P.O.

1965-05-01

By means of neutron activation analysis, injured and adjacent uninjured human heart tissue from 12 autopsy cases with myocardial infarction are investigated with respect to the concentration of 23 trace elements. The bulk elements K, Na and P are also determined. A recently developed ion-exchange technique, combined with subsequent y-spectrometry, is used. The following trace elements are determined: Ag, As, Au, Ba, Br, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Hg, La, Mo, Rb, Sb, Sc, Se, Sm, Zn and W. In the injured tissue compared to the uninjured, calculation on a wet weight basis showed a decrease in Co, Cs, K, Mo, P, Rb and Zn, and an increase in Br, Ca, Ce, La, Na, Sb and Sm. The differences in Ca, La, Mo, P and Zn are dependent on the age of the myocardial infarction, and the regression lines for these elements are given. The concentration of the trace elements in uninjured tissue from infarcted hearts is compared to the concentration of these elements in normal heart tissue, determined in a previous study. In the uninjured tissue from infarcted hearts a decrease is found in Cu and Mo, and an increase in As and Ce

Trace Elements in Human Myocardial Infarction Determined by Neutron Activation Analysis

Energy Technology Data Exchange (ETDEWEB)

Wester, P O

1965-05-15

By means of neutron activation analysis, injured and adjacent uninjured human heart tissue from 12 autopsy cases with myocardial infarction are investigated with respect to the concentration of 23 trace elements. The bulk elements K, Na and P are also determined. A recently developed ion-exchange technique, combined with subsequent y-spectrometry, is used. The following trace elements are determined: Ag, As, Au, Ba, Br, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Hg, La, Mo, Rb, Sb, Sc, Se, Sm, Zn and W. In the injured tissue compared to the uninjured, calculation on a wet weight basis showed a decrease in Co, Cs, K, Mo, P, Rb and Zn, and an increase in Br, Ca, Ce, La, Na, Sb and Sm. The differences in Ca, La, Mo, P and Zn are dependent on the age of the myocardial infarction, and the regression lines for these elements are given. The concentration of the trace elements in uninjured tissue from infarcted hearts is compared to the concentration of these elements in normal heart tissue, determined in a previous study. In the uninjured tissue from infarcted hearts a decrease is found in Cu and Mo, and an increase in As and Ce.

Semiconductor CdF2:Ga and CdF2:In Crystals as Media for Real-Time Holography

Science.gov (United States)

Ryskin, Alexander I.; Shcheulin, Alexander S.; Angervaks, Alexander E.

2012-01-01

Monocrystalline cadmium fluoride is a dielectric solid that can be converted into a semiconductor by doping with donor impurities and subsequent heating in the reduction atmosphere. For two donor elements, Ga and In, the donor (“shallow”) state is a metastable one separated from the ground (“deep”) state by a barrier. Photoinduced deep-to-shallow state transition underlies the photochromism of CdF2:Ga and CdF2:In. Real-time phase holograms are recorded in these crystals capable of following up optical processes in a wide frequency range. The features of photochromic transformations in CdF2:Ga and CdF2:In crystals as well as holographic characteristics of these media are discussed. Exemplary applications of CdF2-based holographic elements are given. PMID:28817009

AgI -Induced Switching of DNA Binding Modes via Formation of a Supramolecular Metallacycle.

Science.gov (United States)

Basak, Shibaji; Léon, J Christian; Ferranco, Annaleizle; Sharma, Renu; Hebenbrock, Marian; Lough, Alan; Müller, Jens; Kraatz, Heinz-Bernhard

2018-03-12

The histidine derivative L1 of the DNA intercalator naphthalenediimide (NDI) forms a triangular Ag I complex (C2). The interactions of L1 and of C2 with DNA were studied by circular dichroism (CD) and UV/Vis spectroscopy and by viscosity studies. Different binding modes were observed for L1 and for C2, as the Ag I complex C2 is too large in size to act as an intercalator. If Ag I is added to the NDI molecule that is already intercalated into a duplex, higher order complexes are formed within the DNA duplex and cause disruptions in the helical duplex structure, which leads to a significant decrease in the characteristic CD features of B-DNA. Thus, via addition of a metal we show how a classic and well-known organic intercalator unit can be turned into a partial metallo insertor. We also show how electrochemical impedance spectroscopy (EIS) can be used to probe DNA binding modes on DNA films that are immobilized on gold surfaces. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Precision electron-gamma spectroscopic studies in 111Cd

International Nuclear Information System (INIS)

Sai Vignesh, T.; Chhetri, Premaditya; Vijay Sai, K.; Gowrishankar, R.; Venkataramaniah, K.; Deepa, S.; Rao, Dwarakarani; Kailas, S.

2011-01-01

The energy levels of 111 Cd has formerly been considered in terms of the states available to the 63rd neutron which is in the 3s 1/2 sub-shell. Kisslinger and Sorensen have used the pairing plus-quadrupole model to predict the energy levels. In the Coulomb excitation experiment only five levels have been excited. The decay of 111 Ag has been investigated only by few workers, Burmistov and Didorenko, Shevlev et al and Goswamy et al. The previous data on level energies, gamma energies and intensities differ considerably even for intense gamma transitions. There has been no detailed study of the internal conversion spectrum. There have been no multipolarity assignments for some of the transitions. An extensive experimental investigation of the gamma and conversion electron spectra has been undertaken to provide precision spectroscopic information on the low lying levels of 111 Cd from the beta decay of 111 Ag

The Changes of Elements Composition in Aspergillus niger and Aspergillus terreus at Different Co2+, Cd2+ and Pb2+ Concentrations Using X-rays Microanalysis

International Nuclear Information System (INIS)

Ouda, S.M.

2010-01-01

X-ray microanalysis in electron microscope allows simultaneous detection and quantitative analysis of several elements so it contributes to understand the role of ions in physiological processes. Energy dispersive X-ray (EDX) analysis used to detect the changes in elements levels in Aspergillus niger and Aspergillus terreus when allowing to grow on Czapek's Dox liquid media amended with different Co 2+ , Cd 2+ and Pb 2+ concentrations and these changes may play a role in fungal uptake for these heavy metal ions. Results showed that Ca, Zn and Cu levels in both fungal isolates significantly decreased (P<0.05) when concentrations of used metal ions increased, also O, Na, Cl and K levels for A. niger and C and P for A. terreus recorded significant reduction (P<0.05) in their percentages. Also, the results revealed that, C and P for A. niger and O, Na, Mg, Cl and K levels for A. terreus significantly increased (P<0.05) as a result of increasing metal ions concentrations. Lack of Cd and Pb peaks in X-ray spectrum for A. terreus led this work to conclude that, A. niger was more effective than A. terreus in Co, Cd, Pb uptake into fungal biomass. The increase or decrease of levels of detected elements could be related to the difference between two fungal isolates in uptake certain heavy metal ion (Co, Cd, Pb)

Colorimetric detection of Cd{sup 2+} using 1-amino-2-naphthol-4-sulfonic acid functionalized silver nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Huang, Pengcheng; Liu, Bowen; Jin, Weiwei; Wu, Fangying, E-mail: fywu@ncu.edu.cn; Wan, Yiqun [Nanchang University, College of Chemistry (China)

2016-11-15

A colorimetric assay has been developed for facile, rapid, and sensitive detection of Cd{sup 2+} using 1-amino-2-naphthol-4-sulfonic acid functionalized silver nanoparticles (ANS-AgNPs). The presence of Cd{sup 2+} induces the aggregation of ANS-AgNPs through cooperative metal–ligand interaction. As a result, the characteristic surface plasmon resonance (SPR) peak of ANS-AgNPs at 390 nm was red-shifted to 580 nm, yielding a color change from bright yellow to reddish-brown. The color change is monitored by UV–Vis spectrometer and can be directly read out by the naked eye. Under the optimized conditions, a good linear relationship (correlation coefficient R = 0.997) was obtained between the ratio of the absorbance at 580 nm to that at 390 nm (A{sub 580nm}/A{sub 390nm}) and the concentration of Cd{sup 2+} over the range of 1.0–10 μM with detection limit of 87 nM. The proposed method is simple and efficient, which has been applied for determining Cd{sup 2+} in milk powder, serum, and lake water with satisfactory results.

Analysis for toxic elements in food and drinking water by means of neutron activation analysis. Final report for the period November 1986 - June 1990

International Nuclear Information System (INIS)

Leelhaphunt, N.

1990-01-01

Neutron activation technique, both instrumental and radiochemical, and atomic absorption spectrophotometry method have been used for the investigation of toxic elements in three hundred and eleven samples of foodstuffs and one hundred and thirty-two samples of drinking water throughout Thailand for human consumption so as to be guideline for establishing the maximum permissible concentration of dietary intake of Ag, As, Br, Cd, Co, Cr, Cu, Fe, Hg, Mn, Pb, Sb, Sc, Se, U, V and Zn in such samples. The estimated daily intake of As, Cd, Cu, Zn, Hg, Se, Pb, Br, Co, Fe, Mn in foodstuffs and As, Co,Cr, Mn, Sb, U, V, Zn in drinking water were reported. 14 refs, 1 fig., 49 tabs

Analysis for toxic elements in food and drinking water by means of neutron activation analysis. Final report for the period November 1986 - June 1990

Energy Technology Data Exchange (ETDEWEB)

Leelhaphunt, N [Office of Atomic Energy for Peace, Bangken, Bangkok (Thailand). Waste Disposal Div.

1991-12-31

Neutron activation technique, both instrumental and radiochemical, and atomic absorption spectrophotometry method have been used for the investigation of toxic elements in three hundred and eleven samples of foodstuffs and one hundred and thirty-two samples of drinking water throughout Thailand for human consumption so as to be guideline for establishing the maximum permissible concentration of dietary intake of Ag, As, Br, Cd, Co, Cr, Cu, Fe, Hg, Mn, Pb, Sb, Sc, Se, U, V and Zn in such samples. The estimated daily intake of As, Cd, Cu, Zn, Hg, Se, Pb, Br, Co, Fe, Mn in foodstuffs and As, Co,Cr, Mn, Sb, U, V, Zn in drinking water were reported. 14 refs, 1 fig., 49 tabs.

Tunneling-recombination luminescence between Ag0 and Ag2+ in KCl:AgCl

International Nuclear Information System (INIS)

Delbecq, C.J.; Dexter, D.L.; Yuster, P.H.

1978-01-01

Appropriate treatment of a KCl:AgCl crystal results in the trapping of electrons as silver atoms, Ag 0 , and positive holes as AgCl 4 2- , Ag 2+ , centers. Optical excitation of Ag 0 in such a crystal at T 0 and Ag 2+ pairs, similar to the Ag 0 -Cl 2 - tunneling-recombination studies we previously reported. We have shown that Ag 2+ centers are involved in the emission process by preferentially orienting the anisotropic Ag 2+ at 6 K by excitation with polarized light and observing that the afterglow is polarized. Upon warming to 50 K, where the preferentially oriented Ag 2+ can change orientation, a strong reversal in the degree of polarization occurs which finally decays to zero. The characteristics of this luminescence can be understood if we assume: (i) a tunneling-recombination mechanism in which the orientation of the electric vector of the emitted radiation depends on the position of the Ag 0 relative to the Ag 2+ and (ii) the tunneling is anisotropic and depends on the location of the Ag 0 relative to the anisotropic Ag 2+ . The latter assumption is based on the tetragonal (d-like) symmetry of the Ag 2+ complex. Good quantitative agreement between theory and experiment has been obtained on the decay kinetics, the degree of polarization, and the polarization reversal

Elemental concentrations of sewage sludge ashes from 1972 to 1994. Trends in environmental pollution and purification technology; Elementgehalte von Klaerschlammaschen 1972-1994. Trends bei Umwelteintraegen und Klaertechnik

Energy Technology Data Exchange (ETDEWEB)

Helmers, E. [Fachhochschule Trier (Germany). Umweltcampus; Wippler, K. [Amt fuer Umweltschutz, Stuttgart (Germany). Chemisches Inst.

1999-06-01

An archive of sewage sludge ashes back to the year 1972 has been analysed for the concentrations of 28 elements exhibiting innovations in the purification technology as well as variations in environmental pollution up to the present. Addition of Al- and Fe-containing precipitating agents also affected signatures of Na, Mo, Ti and Mn. Temporal trends of Mg, K, Li, Sr and Ca are influenced by the mechanism of phosphate reduction. Continuous decrease in the concentrations of Ag, Cr, Ni, Sn, Cd, Cu, Pb and Zn have been traced back to several local as well as general reasons. The decrease of elemental concentrations is discussed with respect to the disposal of sewage sludge on agri- or horticulturally used areas. (orig.) [Deutsch] Aus der Untersuchung archivierter Klaerschlammaschen wird ein Ueberblick ueber die Gehalte von 28 Elementen und ihre zeitliche Entwicklung ueber 23 Jahre vorgelegt. Die dabei gewonnenen Zeitreihen (1972-1994) reflektieren Innovationen und Aenderungen im Klaerverfahren sowie im Eintrag von Elementen und Metallen waehrend dieses Zeitraums. Der Zusatz von Al- und Fe-haltigen Faellmitteln beeinflusste auch die Signaturen der Elemente Na, Mo, Ti und Mn. Die Trendverlaeufe von Mg, K, Li, Sr und Ca weisen auf mechanistische Zusammenhaenge bei der Phosphatelimination hin. Der kontinuierliche Rueckgang der Metalle Ag, Cr, Ni, Sn, Cd, Cu, Pb, Zn konnte mit einer Reihe von lokalen und ueberregionalen Quellen in Zusammenhang gebracht werden. Die Entwicklung der Elementgehalte wird im Hinblick auf eine moegliche landwirtschaftliche Entsorgung diskutiert. (orig.)

Determination of the knight shift in liquid alloys of silver with lanthanides by stroboscopic observation of perturbed angular correlations according to the reaction 109Ag(p,n)109Cd

International Nuclear Information System (INIS)

Gundelfinger, F.

1975-01-01

In liquid alloys of the composition Agsub(1-x)Rsub(x) (0 109 Ag(p,n) 109 Cd* induced by 10 MeV protons. In first appoximation, the values found for the relative change of knight shift prove to be proportional to the negative z-component of the 4f-shell spin of the respective lanthanide metals. The major part of the knight shift is produced by the spin polarization of the conduction electrons due to coupling to the spins of the lanthanide ions. The possible coupling mechanisms are discussed. (orig./GSC) [de

Solution-processed efficient CdTe nanocrystal/CBD-CdS hetero-junction solar cells with ZnO interlayer

Energy Technology Data Exchange (ETDEWEB)

Tian, Yiyao; Zhang, Yijie; Lin, Yizhao; Gao, Kuo; Zhang, Yunpeng; Liu, Kaiyi; Yang, Qianqian [South China University of Technology, School of Materials Science and Engineering (China); Zhou, Xiao; Qin, Donghuan, E-mail: qindh@scut.edu.cn; Wu, Hongbin [South China University of Technology, Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices (China); Xia, Yuxin; Hou, Lintao [Jinan University, College of Science and Engineering (China); Lan, Linfeng; Chen, Junwu; Wang, Dan; Yao, Rihui [South China University of Technology, Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices (China)

2013-11-15

CdTe nanocrystal (NC)/CdS p–n hetero-junction solar cells with an ITO/ZnO-In/CdS/CdTe/MoO{sub x}/Ag-inverted structure were prepared by using a layer-by-layer solution process. The CdS thin films were prepared by chemical bath deposition on top of ITO/ZnO-In and were found to be very compact and pin-hole free in a large area, which insured high quality CdTe NCs thin-film formation upon it. The device performance was strongly related to the CdCl{sub 2} annealing temperature and annealing time. Devices exhibited power conversion efficiency (PCE) of 3.08 % following 400 °C CdCl{sub 2} annealing for 5 min, which was a good efficiency for solution processed CdTe/CdS NC-inverted solar cells. By carefully designing and optimizing the CdCl{sub 2}-annealing conditions (370 °C CdCl{sub 2} annealing for about 15 min), the PCE of such devices showed a 21 % increase, in comparison to 400 °C CdCl{sub 2}-annealing conditions, and reached a better PCE of 3.73 % while keeping a relatively high V{sub OC} of 0.49 V. This PCE value, to the best of our knowledge, is the highest PCE reported for solution processed CdTe–CdS NC solar cells. Moreover, the inverted solar cell device was very stable when kept under ambient conditions, less than 4 % degradation was observed in PCE after 40 days storage.

Performances of Water Management, Foliage Dressing, and Variation Screening in Controlling the Accumulation of As and Cd and Maintaining the Concentrations of Essential Elements in the Grains of Rice Plant

Directory of Open Access Journals (Sweden)

Lei Lei

2018-03-01

Full Text Available This study was conducted to understand why and how the technologies of variety screening, foliar dressing, and water management can reduce As/Cd accumulation and affect the concentrations of essential elements in different rice plants. In Trial I (variety screening, the grain As and Cd concentrations in Zhongguyou1361 variety (P3 were both lower than their individual National Food Hygiene Standard of China (NFHSC under insufficient field drying condition. The P3 also had a relatively high yield and high essential element contents among 15 selected rice varieties. In Trial II (foliar dressing, selenite foliar spray showed a better ability than silicate to reduce the grain As content in Guangliangyou1128 variety (P1. However, spraying Se and Si onto the Fengliangyou1 variety (P2 both showed a limited effect on the grain As and Cd contents, suggesting a different effect of Se on grain As content in various rice varieties. The insufficient field drying in Trial II resulted in the grain Cd content being lower but the grain As content being higher than their individual NFHSC in both P1 and Fengliangyou1 (P2 varieties. Se or Si did not affect the yields and the grain contents of most essential elements in P1 and P2. In Trial III (water management, increasing field drying time enhanced the Cd content but reduced the As content in the grains of P1, P2, and P3, and maintained their yields. Similar to the results of Trial II, the changes in soil pH, organic matter concentration and elemental available concentrations could hardly be used to explain why the contents of corresponding essential elements kept approximately constant in the grains of different rice varieties. Foliar dressing with selenite combined with water regulation can simultaneously reduce the As and Cd contents, and maintain the yields and the essential element contents in the grains of rice plants cultivated in As− and Cd− contaminated soil.

Atmospheric deposition of trace elements in Norway studied by means of moss analysis

International Nuclear Information System (INIS)

Steinnes, E.

1977-02-01

The atmospheric deposition of 28 elements in different parts of Norway was studied by means of moss analysis. The species Hylocomium splendens was selected after a comparison of different species. For several elements large regional differences were found. The highest concentration of these elements were found in the southernmost part of the country and in places near the west coast with high annual precipitation. The lowest values were found in places with low annual precipitation in Eastern Norway and the interior parts of the more northerly parts of the country. Within each region the highest deposition was observed in places with high annual precipitation. For the elements Pb, Sb, As, and Se the observed concentration range amounted to a factor of about 20. In the case of Ag, Cd, Cs, and V the range was smaller, but still amounting to a factor of 10 or more. A lower but still distinct spread was observed for Cr, Mo, Cu, and Zn. For all these elements long distance transport from sources in the densely populated and heavily industrialized parts of Europe probably are of importance for the obsreved distribution. (Auth.)

Identification of a Novel CD8 T Cell Epitope Derived from Plasmodium berghei Protective Liver-Stage Antigen

Directory of Open Access Journals (Sweden)

Alexander Pichugin

2018-01-01

Full Text Available We recently identified novel Plasmodium berghei (Pb liver stage (LS genes that as DNA vaccines significantly reduce Pb LS parasite burden (LPB in C57Bl/6 (B6 mice through a mechanism mediated, in part, by CD8 T cells. In this study, we sought to determine fine antigen (Ag specificities of CD8 T cells that target LS malaria parasites. Guided by algorithms for predicting MHC class I-restricted epitopes, we ranked sequences of 32 Pb LS Ags and selected ~400 peptides restricted by mouse H-2Kb and H-2Db alleles for analysis in the high-throughput method of caged MHC class I-tetramer technology. We identified a 9-mer H-2Kb restricted CD8 T cell epitope, Kb-17, which specifically recognized and activated CD8 T cell responses in B6 mice immunized with Pb radiation-attenuated sporozoites (RAS and challenged with infectious sporozoites (spz. The Kb-17 peptide is derived from the recently described novel protective Pb LS Ag, PBANKA_1031000 (MIF4G-like protein. Notably, immunization with the Kb-17 epitope delivered in the form of a minigene in the adenovirus serotype 5 vector reduced LPB in mice infected with spz. On the basis of our results, Kb-17 peptide was available for CD8 T cell activation and recall following immunization with Pb RAS and challenge with infectious spz. The identification of a novel MHC class I-restricted epitope from the protective Pb LS Ag, MIF4G-like protein, is crucial for advancing our understanding of immune responses to Plasmodium and by extension, toward vaccine development against malaria.

Construction of Ag/AgCl nanostructures from Ag nanoparticles as high-performance visible-light photocatalysts

Energy Technology Data Exchange (ETDEWEB)

Yang, Fan; Liu, Dongzhi; Wang, Tianyang; Li, Wei [Tianjin University, School of Chemical Engineering and Technology (China); Hu, Wenping [Tianjin University, Collaborative Innovation Center of Chemical Science and Engineering (China); Zhou, Xueqin, E-mail: zhouxueqin@tju.edu.cn [Tianjin University, School of Chemical Engineering and Technology (China)

2016-11-15

A combined strategy of in situ oxidation and assembly is developed to prepare Ag/AgCl nanospheres and nanocubes from Ag nanoparticles under room temperature. It is a new facile way to fabricate Ag/AgCl with small sizes and defined morphologies. Ag/AgCl nanospheres with an average size of 80 nm were achieved without any surfactants, while Ag/AgCl nanocubes with a mean edge length of 150 nm were obtained by introduction of N-dodecyl-N,N-dimethyl-2-ammonio-acetate. The possible formation mechanism involves the self-assembly of AgCl nanoparticles, Ostwald ripening and photoreduction of Ag{sup +} into Ag{sup 0} by the room light. The as-prepared Ag/AgCl nanospheres and nanocubes exhibit excellent photocatalytic activity and stability toward degradation of organic pollutants under visible-light irradiation. It is demonstrated that Ag/AgCl nanocubes display enhanced photocatalytic activity in comparison with Ag/AgCl nanospheres due to the more efficient charge transfer. This work may pave an avenue to construct various functional materials via the assembly strategy using nanoparticles as versatile building blocks.

Anion-exchange Studies of Radioactive Trace Elements in Sulphuric Acid Solutions

Energy Technology Data Exchange (ETDEWEB)

Samsahl, K

1963-01-15

As part of a chemical group separation procedure used as a pretreatment in gamma spectrometric analysis, a study has been made of the adsorption from sulphuric acid solutions on strongly basic anion exchange resins, prepared in the hydroxide and the sulphate forms, of trace activities of Na, P, K, Ca, Sc, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Rb, Sr, Zr, Nb, Mo, Tc, Ag, Cd, In, Cs, Ba, La, Ce, Hf, Ta, W, Ir, Pa and Np. Besides adsorbing some of the trace elements in the solution, the anion exchange resin in the hydroxide form will neutralize the bulk of the sulphuric acid. This makes possible the subsequent sequential separation of chloride complexes on short anion-exchange columns by a stepwise increasing of the HCl concentration of the solution. On the basis of the results obtained in the present and earlier experiments, a new improved chemical group-separation procedure for mixtures of radioactive trace elements is outlined.

A new Schiff base based on vanillin and naphthalimide as a fluorescent probe for Ag+ in aqueous solution

Science.gov (United States)

Zhou, Yanmei; Zhou, Hua; Ma, Tongsen; Zhang, Junli; Niu, Jingyang

2012-03-01

A new Schiff base based on vanillin and naphthalimide was designed and synthesized as fluorescent probe. The probe showed high selectivity for Ag+ over other metal ions such as Pb2+, Na+, K+, Cd2+, Ba2+, Cr3+, Zn2+, Cu2+, Ni2+, Ca2+, Al3+ and Mg2+ in aqueous solution. A new fluorescence emission was observed at 682 nm in the presence of Ag+ ion. The fluorescence intensity quenched with increasing the concentration of Ag+ at 682 nm. The method of job's plot confirmed the 1:2 complex between Ag+ and probe, and the mechanism was proposed.

Metallic elements and metalloids in Boletus luridus, B. magnificus and B. tomentipes mushrooms from polymetallic soils from SW China.

Science.gov (United States)

Falandysz, Jerzy; Zhang, Ji; Wiejak, Anna; Barałkiewicz, Danuta; Hanć, Anetta

2017-08-01

Yunnan Province in China is known for its high biodiversity of mushrooms and a diverse geochemistry of soil bedrock and polymetallic soils, but our knowledge of mineral compositions of mushrooms from Yunnan is scarce. The metallic trace elements, Ag, Ba, Co, Cd, Cs, Cu, Cr, Hg, Li, Mn, Ni, Pb, Rb, Sr, V, Tl, U and Zn, and the metalloids, As and Sb, have been investigated using validated methods with a dynamic reactive cell by mass spectroscopy - inductive coupled plasma and cold vapour - atomic absorption spectroscopy on three popular species of Boletus mushrooms from Southwestern China. The trace mineral profiles in caps and stipes of B. luridus (24 individuals), B. magnificus (29 individuals) and B. tomentipes (38 individuals) have been evaluated. The interspecific differences in the content of several trace elements could be attributed to known differences in the geochemistry of soils in Yunnan, but for copper a difference was observed within species. The mean values of concentrations in composite samples of caps for B. luridus, B. magnificus and B. tomentipes from three to four locations were at the ranges (mgkg -1 dry biomass): Ag (1.3-3.7), As (0.79-53), Ba (4.0-12), Co (0.68-1.2), Cd (0.79-2.2), Cs (0.67-55), Cu (37-77), Cr (5.0-7.6), Hg (2.1-5.4), Li (0.15-0.61), Mn (13-28), Ni (0.86-4.6), Pb (0.59-1.8), Rb (90-120), Sb (0.014-0.088), Sr (0.63-1.6), V (1.4-2.2), Tl (0.017-0.054), U (0.029-0.065) and Zn (130-180). Caps of Boletus mushrooms were richer in Ag, Cu, Hg and Zn than stipes, while other elements were distributed roughly equally between both morphological parts. B. luridus, B. magnificus and B. tomentipes grew in certain sites in Yunnan contained Ag, As, Ba, Cr, Hg, Ni, Sr or V at elevated concentration. A specific geochemistry of the soils type (latosols, lateritic red earths, and red and yellow earths in the Circum-Pacific Mercuriferous Belt of Southwestern China) can explain occurrence of some minerals at greater or elevated amount in mushrooms

E3-transitions in sup(105, 107, 109, 111)Ag

International Nuclear Information System (INIS)

Shevelev, G.A.; Troitskaya, A.G.; Kartashov, V.M.

1978-01-01

Electron radiation of the isomeric transitions of the sup(105-111)Ag odd nuclei was studied using an iron magnetic πsup(√2) beta spectrometer. For most isomeric transitions, relative intensities of the K, L, M, and N lines have been measured; for sup(105-111)Ag and 111 Cd they were measured for the first time. Energy of gamma transitions, relative intensities of internal conversion electrons (ICE) compared with the theoretical ICE values for the E3 transitions are presented. The observations for all the shells are in a fairly gool agreement with the calculations. Systematics of low-lying excited states of the silver nuclei involved is proposed. It has been established that spins and parities of the first excited states of the sup(105-111)Ag odd nuclei are 7/2 + . Multipolarities of isomeric transitions from these staes are pure E3. Spin and parity 9/2 + of the second excited states may be uniquely determined unly for 109 Ag from direct measurements of the ICE transition at 45.8 keV

Characterizing the economic value of an epithermal Au-Ag ore with Laser Induced Breakdown Spectroscopy (LIBS)

NARCIS (Netherlands)

Dalm, M.; Buxton, M.W.N.

2016-01-01

LIBS was applied to 19 Au-Ag ore samples to investigate if this technique can be used to distinguish between economic and sub-economic ore either by direct detection of these elements or by using other elements as indicators. However, the Au and Ag grades of the samples are below the detection limit

ANALISIS UNSUR Ag PADA SAMPEL CAIR DENGAN LASER INDUCED BREAKDOWN SPECTROSCOPY (LIBS

Directory of Open Access Journals (Sweden)

Sinaga Natalia Declarossy

2014-02-01

Full Text Available It has been done research on the analysis of Ag element in the liquid electrolyte with Laser Induced Breakdown Spectroscopy (LIBS through electrolysis method. Observations conducted by LIBS using Nd-YAG laser (1064nm, 7ns. Prior to analyze, first looking for the optimum conditions of experiments had been done. The results showed that the optimum laser energy to the characterization of the elements Ag was 100 mJ and optimum conditions of electric current and time deposition on electrolysis process were 4.93 mA and 10 minutes, respectively. These conditions, next, for the application of quantitative analysis of Ag solution that started from concentration 300 ppm to the lowest concentration and limit of detection obtained 1 ppm.

Evaluation on the Toxic Effects of NanoAg to Catalase.

Science.gov (United States)

Zhang, Bin; Zhai, Wenxin; Liu, Rutao; Yu, Zehua; Shen, Hengmei; Hu, Xinxin

2015-02-01

Protein is the functional actor of life. Research on protein damage induced by nanomaterials may give insight into the toxicity mechanisms of nanoparticles. Studying nano silver over the impact of the structure and function of catalase (CAT) at the molecular level, is of great significance for a comprehensive evaluation of their toxic effects. The toxic effects of nanoAg on catalase were thoroughly investigated using steady state and time resolved fluorescence quenching measurements, ultraviolet-visible absorption spectroscopy, resonance light scattering spectroscopy (RLS), circular dichroism spectroscopy (CD) and transmission electron microscopy (TEM). NanoAg could decrease the amount of alpha-helix and increase the beta sheet structure, leading to loose the skeleton structure of catalase. The characteristic fluorescence of catalase was obviously quenched, which showed the exposal of internal hydrophobic amino acids enhanced, and its quenching type is dynamic quenching. The result of RLS and TEM showed that the distribution and size of nanoAg become more uniform and smaller after their interaction, resulting in a decrease of RLS intensity. NanoAg could make the activity of catalase rise. By changing the structure of catalase, nanoAg increases its enzymatic activity to a certain extent, breaking down its balance in vivo, thereby affecting the normal physiological activities. NanoAg has obvious toxic effects on catalase. This paper provided a new perspective and method for the toxic effects of nanoAg to biological macromolecules; provided basic data and reference gist for the hygienics and toxicology studies of nanoAg. It is conducive to the toxicity prevention and control work of nanoAg, promoting nano-technology applied to human production and living better.

Concentrations of trace elements in American alligators (Alligator mississippiensis) from Florida, USA.

Science.gov (United States)

Horai, Sawako; Itai, Takaaki; Noguchi, Takako; Yasuda, Yusuke; Adachi, Haruki; Hyobu, Yuika; Riyadi, Adi S; Boggs, Ashley S P; Lowers, Russell; Guillette, Louis J; Tanabe, Shinsuke

2014-08-01

Concentrations of 28 trace elements (Li, Mg, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Mo, Ag, Cd, In, Sn, Sb, Cs, Tl, Hg, Pb, and Bi) in the livers of juvenile and adult American alligators inhabiting two central Florida lakes, Lake Apopka (LA), and Lake Woodruff National Wildlife Refuge (LW) and one lagoon population located in Merritt Island National Wildlife Refuge (MINWR; NASA), were determined. In juveniles from MINWR, concentrations of nine elements (Li, Fe, Ni, Sr, In, Sb, Hg, Pb and Bi) were significantly higher, whereas six elements (V, Fe, As, Sr, Hg and Bi) were elevated in adults (pLA, LW and MINWR were 1770 μg g(-1) DW, 3690 μg g(-1) DW and 5250 μg g(-1) DW, respectively. More than half of the adult specimens from LW and MINWR exhibited elevated hepatic Fe concentrations that exceed the threshold value for toxic effects in donkey, red deer and human. These results prompted us to express our concern on possible exposure and health effects in American alligators by some trace elements derived from NASA activities. Copyright © 2014 Elsevier Ltd. All rights reserved.

Spatial distribution of trace elements in the surface sediments of a major European estuary (Loire Estuary, France): Source identification and evaluation of anthropogenic contribution

Science.gov (United States)

Coynel, Alexandra; Gorse, Laureline; Curti, Cécile; Schafer, Jörg; Grosbois, Cécile; Morelli, Guia; Ducassou, Emmanuelle; Blanc, Gérard; Maillet, Grégoire M.; Mojtahid, Meryem

2016-12-01

Assessing the extent of metal contamination in estuarine surface sediments is hampered by the high heterogeneity of sediment characteristics, the spatial variability of trace element sources, sedimentary dynamics and geochemical processes in addition to the need of accurate reference values for deciphering natural to anthropogenic contribution. Based on 285 surface sediment samples from the Loire Estuary, the first high-resolution spatial distributions are presented for grain-size, particulate organic carbon (POC) and the eight metals/metalloids identified as priority contaminants (Cd, Zn, Pb, Cu, As, Cr, Ni, Hg) plus Ag (an urban tracer). Grain-size and/or POC are major factors controlling the spatial distribution of trace element concentrations. The V-normalized trace metal concentrations divided by the V-normalized concentrations in the basin geochemical background showed the highest Enrichment Factors for Ag and Hg (EF; up to 34 and 140, respectively). These results suggest a severe contamination in the Loire Estuary for both elements. Intra-estuarine Ag and Hg anomalies were identified by comparison between respective normalized concentrations in the Loire Estuary surface sediments and those measured in the surface sediments at the outlet of the Loire River System (watershed-derived). Anthropogenic intra-estuarine Ag and Hg stocks in the uppermost centimetre of the sediment compared with rough annual fluvial flux estimates suggest that the overall strong Enrichment Factors for Ag (EFAg) and and Hg (EFHg) in the Loire Estuary sediments are mainly due to watershed-derived inputs, highlighting the need of high temporal hydro-geochemical monitoring to establish reliable incoming fluxes. Significant correlations obtained between EFCd and EFAg, EFCu and POC and EFHg and POC revealed common behavior and/or sources. Comparison of trace element concentrations with ecotoxicological indices (Sediment Quality Guidelines) provides first standardized information on the

Elucidating the real-time Ag nanoparticle growth on α-Ag2WO4 during electron beam irradiation: experimental evidence and theoretical insights.

Science.gov (United States)

Pereira, Wyllamanney da Silva; Andrés, Juan; Gracia, Lourdes; San-Miguel, Miguel A; da Silva, Edison Z; Longo, Elson; Longo, Valeria M

2015-02-21

Why and how Ag is formed when electron beam irradiation takes place on α-Ag2WO4 in a vacuum transmission electron microscopy chamber? To find an answer, the atomic-scale mechanisms underlying the formation and growth of Ag on α-Ag2WO4 have been investigated by detailed in situ transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM) studies, density functional theory based calculations and ab initio molecular dynamics simulations. The growth process at different times, chemical composition, size distribution and element distribution were analyzed in depth at the nanoscale level using FE-SEM, operated at different voltages (5, 10, 15, and 20 kV), and TEM with energy dispersive spectroscopy (EDS) characterization. The size of Ag nanoparticles covers a wide range of values. Most of the Ag particles are in the 20-40 nm range. The nucleation and formation of Ag on α-Ag2WO4 is a result of structural and electronic changes in the AgOx (x = 2,4, 6, and 7) clusters used as constituent building blocks of this material, consistent with metallic Ag formation. First principle calculations point out that Ag-3 and Ag-4-fold coordinated centers, located in the sub-surface of the (100) surface, are the most energetically favorable to undergo the diffusion process to form metallic Ag. Ab initio molecular dynamics simulations and the nudged elastic band (NEB) method were used to investigate the minimum energy pathways of these Ag atoms from positions in the first slab layer to outward sites on the (100) surface of α-Ag2WO4. The results point out that the injection of electrons decreases the activation barrier for this diffusion step and this unusual behavior results from the presence of a lower energy barrier process.

High temperature electron beam ion source for the production of single charge ions of most elements of the Periodic Table

CERN Document Server

Panteleev, V N; Barzakh, A E; Fedorov, D V; Ivanov, V S; Moroz, F V; Orlov, S Y; Seliverstov, D M; Stroe, L; Tecchio, L B; Volkov, Y M

2003-01-01

A new type of a high temperature electron beam ion source (HTEBIS) with a working temperature up to 2500 deg. C was developed for production of single charge ions of practically all elements. Off-line tests and on-line experiments making use of the developed ion source coupled with uranium carbide targets of different density, have been carried out. The ionization efficiency measured for stable atoms of many elements varied in the interval of 1-6%. Using the HTEBIS, the yields and on-line production efficiency of neutron rich isotopes of Mn, Fe, Co, Cu, Rh, Pd, Ag, Cd, In, Sn and isotopes of heavy elements Pb, Bi, Po and some others have been determined. The revealed confinement effect of the ions produced in the narrow electron beam inside a hot ion source cavity has been discussed.

Preliminary study of CdTe and CdTe:Cu thin films nanostructures deposited by using DC magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Marwoto, Putut; Made, D. P. Ngurah; Sugianto [Departement of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Semarang, Gunungpati, Semarang 50229 Jawa Tengah (Indonesia); Wibowo, Edy; Astuti, Santi Yuli; Aryani, Nila Prasetya [Materials Research Group, Laboratory of Thin Film, Department of Physics, Universitas Negeri Semarang, Gunungpati, Semarang 50229 Jawa Tengah (Indonesia); Othaman, Zulkafli [Departement of Physics, Universiti Teknologi Malaysia (UTM), Skudai, Johor Bahru (Malaysia)

2013-09-03

Growth and properties of CdTe and CdTe:Cu thin films nanostrucures deposited by using dc magnetron sputtering are reported. Scanning electron microscope (SEM) was used to observe the surface morphologies of the thin films. At growth conditions of 250 °C and 14 W, CdTe films did not yet evenly deposited. However, at growth temperature and plasma power of 325 °C and 43 W, both CdTe and CdTe:Cu(2%) have deposited on the substrates. In this condition, the morphology of the films indicate that the films have a grain-like nanostructures. Grain size diameter of about 200 nm begin to appear on top of the films. Energy Dispersive X-rays spectroscopy (EDX) was used to investigate chemical elements of the Cu doped CdTe film deposited. It was found that the film deposited consist of Cd, Te and Cu elements. XRD was used to investigate the full width at half maximum (FWHM) values of the thin films deposited. The results show that CdTe:Cu(2%) thin film has better crystallographic properties than CdTe thin film. The UV-Vis spectrometer was used to investigate the optical properties of thin films deposited. The transmittance spectra showed that transmittance of CdTe:Cu(2%) film is lower than CdTe film. It was found that the bandgap energy of CdTe and CdTe:Cu(2%) thin films of about 1.48 eV.

Percentage of toxic trace elements; Pb, Cr and Cd in certain plastic toys, Isfahan City

Directory of Open Access Journals (Sweden)

F Kavehzadeh

2006-04-01

Full Text Available Introduction: Recent investigations have detected the presence of significant levels of heavy metals (chromium, lead and cadmium in toys and other PVC products manufactured for children. In some countries, addition of compounds containing toxic metals to toys are limited or prohibited. Methods: To evaluate the safety of some of the plastic toys in the city of Isfahan with respect to toxic trace metals, pb, cr and cd, 75 samples of three types of toys were collected from the toy shop’s and were digested with acid with the two methods ISIRI and ASTM. The heavy metals were determined using atomic absorption spectrophotometer. Variance analysis and T-test were used for data analysis. Results: The result of the study showed that the products tested contained lead, chromium and cadmium and the highest and lowest concentration were related to Pb and Cd, respectively. The statistical analysis of the samples showed that there are no significant differences between ASTM and ISIRI digestion methods. The study revealed that none of the heavy metals in the toy samples exceeded the recommended standard levels. Highest average concentration of Pb and Cd were related to toys with green color and the highest Cr concentration was related to yellow toys in this study. Conclusion: Extensive studies are required to evaluate the quality of the toys being used by children and the toxic trace elements should be eliminated from the plastic materials used for making toys.

Active Sphagnum girgensohnii Russow Moss Biomonitoring of an Industrial Site in Romania: Temporal Variation in the Elemental Content.

Science.gov (United States)

Culicov, Otilia A; Zinicovscaia, Inga; Duliu, O G

2016-05-01

The moss-bag transplant technique was used to investigate the kinetics of the accumulation of 38 elements in Sphagnum girgensohni moss samples in the highly polluted municipality of Baia Mare, Romania. The moss samples collected from the unpolluted Vitosha Mountain Natural Reserve, Bulgaria, were analyzed after 1, 2, 3, and 4 months of exposure, respectively. The ANOVA method was used to assay the statistical significance of the observed changes in elemental content, as determined by neutron activation analysis. The content of Zn, Se, As, Ag, Cd, and Sb increased steadily, while that of physiologically active K and Cl, as well as Rb and Cs, decreased exponentially. The study showed that an adequate application of the moss transplant technique in an urban environment should consider the exposure time as a critical parameter, since particular elements are depleted in the moss at sites with high atmospheric loading of metals.

Spectroscopic exploration of interaction between PEG-functionalized Ag2S nanoparticles with bovine serum albumin

Science.gov (United States)

Prasanth, S.; RitheshRaj, D.; Vineeshkumar, T. V.; Sudarsanakumar, C.

2018-05-01

The introduction of nanoparticles into biological fluids often leads to the formation of biocorona over the surface of nanoparticles. For the effective use of nanoparticles in biological applications it is very essential to understand their interactions with proteins. Herein, we investigated the interactions of Poly ethylene glycol capped Ag2S nanoparticles with Bovine Serum Albumin by spectroscopic techniques. By the addition of Ag2S nanoparticles, a ground state complex is formed. The CD spectroscopy reveals that the secondary structure of BSA is altered by complexation with PEG-Ag2S nanoparticles, while the overall tertiary structure remains closer to that of native BSA.

Specific composition of native silver from the Rogovik Au-Ag deposit, Northeastern Russia

Science.gov (United States)

Kravtsova, R. G.; Tauson, V. L.; Palyanova, G. A.; Makshakov, A. S.; Pavlova, L. A.

2017-09-01

The first data on native silver from the Rogovik Au-Ag deposit in northeastern Russia are presented. The deposit is situated in central part of the Okhotsk-Chukchi Volcanic Belt (OCVB) in the territory of the Omsukchan Trough, unique in its silver resources. Native silver in the studied ore makes up finely dispersed inclusions no larger than 50 μm in size, which are hosted in quartz; fills microfractures and interstices in association with küstelite, electrum, acanthite, silver sulfosalts and selenides, argyrodite, and pyrite. It has been shown that the chemical composition of native silver, along with its typomorphic features, is a stable indication of the various stages of deposit formation and types of mineralization: gold-silver (Au-Ag), silver-base metal (Ag-Pb), and gold-silver-base metal (Au-Ag-Pb). The specificity of native silver is expressed in the amount of trace elements and their concentrations. In Au-Ag ore, the following trace elements have been established in native silver (wt %): up to 2.72 S, up to 1.86 Au, up to 1.70 Hg, up to 1.75 Sb, and up to 1.01 Se. Native silver in Ag-Pb ore is characterized by the absence of Au, high Hg concentrations (up to 12.62 wt %), and an increase in Sb, Se, and S contents; the appearance of Te, Cu, Zn, and Fe is notable. All previously established trace elements—Hg, Au, Sb, Se, Te, Cu, Zn, Fe, and S—are contained in native silver of Au-Ag-Pb ore. In addition, Pb appears, and silver and gold amalgams are widespread, as well as up to 24.61 wt % Hg and 11.02 wt % Au. Comparison of trace element concentrations in native silver at the Rogovik deposit with the literature data, based on their solubility in solid silver, shows that the content of chalcogenides (S, Se, Te) exceeds saturated concentrations. Possible mechanisms by which elevated concentrations of these elements are achieved in native silver are discussed. It is suggested that the appearance of silver amalgams, which is unusual for Au-Ag mineralization

Elemental characterization of coal ash and its leachates using sequential extraction techniques

International Nuclear Information System (INIS)

Landsberger, S.; Cerbus, J.F.; Larson, S.

1995-01-01

Over 50 million tons of coal ash are produced annually in North America. Technological improvements in air pollution control have decreased stack emissions but have also increased contaminant concentrations in the ash of coal-fired boiler applications. The leaching of heavy metals and other elements during regulatory tests may cause coal ash to be classified as hazardous waste, complicating land disposal. The hazardous nature of coal ash remains unclear because current toxicity tests fail to effectively characterize the elemental distribution and chemical solubility of trace metals in the landfill environment. Leaching characteristics of ash samples can be investigated with various laboratory extraction procedures in association with multi-elemental analytical techniques (e.g., neutron activation analysis and inductively coupled plasma - atomic emission spectroscopy). Such methods provide more thorough analyses of coal ash leaching dynamics than the regulatory assessments can demonstrate. Regulatory elements including Ag, As, Ba, Cd, Cr, Hg, Pb, and Se were shown to remain in largely insoluble forms while elements such as B and S leached at higher levels. Experimental results may assist operators of coal-fired boiler industries in selecting coal types and disposal options to curtail the leaching of potentially toxic inorganic contaminants. (author) 12 refs.; 4 figs.; 3 tabs

Radiochemical synthesis of {sup 105g}Ag-labelled silver nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Ichedef, C., E-mail: cigdem_ch@yahoo.com; Simonelli, F.; Holzwarth, U. [Institute for Health and Consumer Protection, European Commission, Joint Research Centre (Italy); Bagaria, J. Piella; Puntes, V. F. [Institut Català de Nanotecnologia (ICN2) (Spain); Cotogno, G.; Gilliland, D.; Gibson, N. [Institute for Health and Consumer Protection, European Commission, Joint Research Centre (Italy)

2013-11-15

A method for synthesis of radiolabelled silver nanoparticles is reported. The method is based on proton activation of silver metal powder, enriched in {sup 107}Ag, with a 30.7 MeV proton beam. At this proton energy {sup 105g}Ag is efficiently created, mainly via the {sup 107}Ag(p,3n){sup 105}Cd → {sup 105g}Ag reaction. {sup 105g}Ag has a half-life of 41.29 days and emits easily detectable gamma radiation on decay to {sup 105}Pd. This makes it very useful as a tracing radionuclide for experiments over several weeks or months. Following activation and a period to allow short-lived radionuclides to decay, the powder was dissolved in concentrated nitric acid in order to form silver nitrate (AgNO{sub 3}), which was used to synthesise radiolabelled silver nanoparticles via the process of sodium borohydride reduction. For comparison, non-radioactive silver nanoparticles were synthesised using commercially supplied AgNO{sub 3} in order to check if the use of irradiated Ag powder as a starting material would alter in any way the final nanoparticle characteristics. Both nanoparticle types were characterised using dynamic light scattering, zeta-potential and X-ray diffraction measurements, while additionally the non-radioactive samples were analysed by transmission electron microscopy and UV–Vis spectrometry. A hydrodynamic diameter of about 16 nm was determined for both radiolabelled and non-radioactive nanoparticles, while the electron microscopy on the non-radioactive samples indicated that the physical size of the metal NPs was (7.3 ± 1.4) nm.

Multi-Element Composition of Honey as a Suitable Tool for Its Authenticity Analysis

Directory of Open Access Journals (Sweden)

Oroian Mircea

2015-06-01

Full Text Available The aim of this study was to evaluate the composition of 36 honey samples of 4 different botanical origins (acacia, sun flower, tilia and honeydew from the North East region of Romania. An inductively coupled plasma-mass spectrometry (ICP-MS method was used to determine 27 elements in honey (Ag, Al, As, Ba, Be, Ca, Cd, Co, Cr, Cs, Cu, Fe, Ga, K, Li, Mg, Mn, Na, Ni, Pb, Rb, Se, Sr, Tl, U, V and Zn. We would like to achieve the following goal: to demonstrate that the qualitative and quantitative multi-element composition determination of honey can be used as a suitable tool to classify honey according to its botanical origin. The principal component analysis allowed the reduction of the 27 variables to 2 principal components which explained 74% of the total variance. The dominant elements which were strongly associated with the principal component were K, Mg and Ca. Discriminant models obtained for each kind of botanical honey confirmed that the differentiation of honeys according to their botanical origin was mainly based on multi-element composition. A correct classification of all samples was achieved with the exception of 11.1% of honeydew honeys.

Implications for food safety of the uptake by tomato of 25 trace-elements from a phosphogypsum amended soil from SW Spain

International Nuclear Information System (INIS)

Enamorado, Santiago; Abril, José M.; Delgado, Antonio; Más, José L.; Polvillo, Oliva; Quintero, José M.

2014-01-01

Highlights: • Uptake of 25 trace-elements by tomato was studied in phosphogypsum-amended soils. • Cadmium had high transfer factors in tomato shoots (4.0) and fruits (1.5). • These two TF values of Cd increased to 5.7 and 2.5 after PG-inputs, respectively. • PG decreased the concentration of B, Cu, Sb, Cs, Ba, Tl and Th in fruits. • Assessment on trace elements in PG is needed to avoid exceeding legal limits in food. -- Abstract: Phosphogypsum (PG) has been usually applied as Ca-amendment to reclaim sodic soils such as those in the marshland area of Lebrija (SW Spain). This work aimed at the effects of PG amendments on the uptake of trace-elements by tomato and its implications for food safety. A completely randomized experiment was performed using a representative soil from Lebrija in a greenhouse involving six replicates and four PG treatments equivalent to 0, 20, 60, and 200 Mg ha −1 . Soil-to-plant transfer factors (TFs) were determined for Be, B, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Mo, Ag, Cd, Sb, Cs, Ba, Tl, Pb, Th and U. The highest TF in shoots was observed for Cd (4.0; 1.5 in fruits), its concentration being increased with increasing PG doses due to its content in this metal (2.1 mg Cd kg −1 PG). Phosphogypsum applying decreased the concentrations of Mn, Co and Cu in shoots; and of B, Cu, Sb, Cs, Ba, Tl and Th in fruits, however enhanced the accumulation of Se in fruits. Although Cd concentrations in tomato were below the maximum allowed levels in control pots (0 Mg PG ha −1 ), PG amendments above 60 Mg ha −1 exceeded such limits

Implications for food safety of the uptake by tomato of 25 trace-elements from a phosphogypsum amended soil from SW Spain

Energy Technology Data Exchange (ETDEWEB)

Enamorado, Santiago [Departamento de Física Aplicada I, Universidad de Sevilla, EPS, c/Virgen de África n° 7, D.P. 41011, Seville (Spain); Abril, José M., E-mail: jmabril@us.es [Departamento de Física Aplicada I, Universidad de Sevilla, EPS, c/Virgen de África n° 7, D.P. 41011, Seville (Spain); Delgado, Antonio [Departamento de Ciencias Agroforestales, Universidad de Sevilla, ETSIA, Ctra. Utrera km. 1, D.P. 41013, Seville (Spain); Más, José L. [Departamento de Física Aplicada I, Universidad de Sevilla, EPS, c/Virgen de África n° 7, D.P. 41011, Seville (Spain); Polvillo, Oliva [Agricultural Research Service of the University of Seville (SIA-CITIUS), Ctra. Utrera Km. 1, D.P. 41013, Seville (Spain); Quintero, José M. [Departamento de Ciencias Agroforestales, Universidad de Sevilla, ETSIA, Ctra. Utrera km. 1, D.P. 41013, Seville (Spain)

2014-02-15

Highlights: • Uptake of 25 trace-elements by tomato was studied in phosphogypsum-amended soils. • Cadmium had high transfer factors in tomato shoots (4.0) and fruits (1.5). • These two TF values of Cd increased to 5.7 and 2.5 after PG-inputs, respectively. • PG decreased the concentration of B, Cu, Sb, Cs, Ba, Tl and Th in fruits. • Assessment on trace elements in PG is needed to avoid exceeding legal limits in food. -- Abstract: Phosphogypsum (PG) has been usually applied as Ca-amendment to reclaim sodic soils such as those in the marshland area of Lebrija (SW Spain). This work aimed at the effects of PG amendments on the uptake of trace-elements by tomato and its implications for food safety. A completely randomized experiment was performed using a representative soil from Lebrija in a greenhouse involving six replicates and four PG treatments equivalent to 0, 20, 60, and 200 Mg ha{sup −1}. Soil-to-plant transfer factors (TFs) were determined for Be, B, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Mo, Ag, Cd, Sb, Cs, Ba, Tl, Pb, Th and U. The highest TF in shoots was observed for Cd (4.0; 1.5 in fruits), its concentration being increased with increasing PG doses due to its content in this metal (2.1 mg Cd kg{sup −1} PG). Phosphogypsum applying decreased the concentrations of Mn, Co and Cu in shoots; and of B, Cu, Sb, Cs, Ba, Tl and Th in fruits, however enhanced the accumulation of Se in fruits. Although Cd concentrations in tomato were below the maximum allowed levels in control pots (0 Mg PG ha{sup −1}), PG amendments above 60 Mg ha{sup −1} exceeded such limits.

On electrochemical sensor for determining elemental iodine in gas media

International Nuclear Information System (INIS)

Goffman, V.G.; Shajmerdinov, B.U.; Kotelkin, I.M.; Mikhajlova, A.M.; Dobrovol'skij, Yu.A.

1993-01-01

The possibility to use solid electrolyte cells of Ag, AgI/AgI/Au as sensors for determining concentration of element iodine in gaseous media was studied. Independent character of sensor parameters on oxygen content and radiation burden at different humidity was ascertained

Finite Element-Assisted Assessment of the Thermo-cyclic Characteristics of Leads Soldered with SnAgCu(+Bi,In) Alloys

Science.gov (United States)

Lis, Adrian; Nakanishi, Kohei; Matsuda, Tomoki; Sano, Tomokazu; Minagawa, Madoka; Okamoto, Masahide; Hirose, Akio

2017-07-01

Solder joints between leads and printed circuit boards in thin small outline packages were produced with conventional Sn1.0Ag0.7Cu (SAC107) and Sn3.0Ag0.7Cu (SAC305) solders as well as various solder alloys with gradually increasing amounts of Bi (up to 3.0 wt.%) and In (up to 1.0 wt.%) within the SAC107 base solder. The reliability of soldered leads in temperature cycle (TC) tests improved most with solder alloys containing both Bi (1.6 wt.%) and In (0.5 wt.%). Microindentation and electron probe microanalysis mappings revealed that the effect originates from a combination of solution and precipitation strengthening of the initial SAC alloy. The distribution of inelastic strain accumulation (ISA), as a measure for degradation, was determined in the solder joints by finite element calculations. It was shown that defects in the solder proximal to the lead (60-75 μm), which was underpinned by similar cracking characteristics along the lead-solder interface. The ISA was confirmed to be lower in SAC+Bi/In alloys owing to their enhanced elasto-plastic properties. Moreover, the addition of a thin Cu coating on the leads could improve the joint reliability, as suggested by the calculation of the ISA and the acceleration factor.

Visible light driven photocatalysis and antibacterial activity of AgVO3 and Ag/AgVO3 nanowires

International Nuclear Information System (INIS)

Singh, Anamika; Dutta, Dimple P.; Ballal, A.; Tyagi, A.K.; Fulekar, M.H.

2014-01-01

Graphical abstract: - Highlights: • Ag/AgVO 3 and pure AgVO 3 nanowires synthesized by sonochemical process. • Characterization done using XRD, SEM, TEM, EDX and BET analysis. • Visible light degradation of RhB by Ag/AgVO 3 within 45 min. • Antibacterial activity of Ag/AgVO 3 demonstrated. - Abstract: Ag/AgVO 3 nanowires and AgVO 3 nanorods were synthesized in aqueous media via a facile sonochemical route. The as-synthesized products were characterized by X-ray diffraction, Brunauer–Emmett–Teller surface area analysis, scanning electron microscopy together with an energy dispersion X-ray spectrum analysis, transmission electron microscopy and UV–vis diffuse reflectance spectroscopy. The results revealed that inert atmosphere promotes the formation of Ag/AgVO 3 nanowires. The photocatalytic studies revealed that the Ag/AgVO 3 nanowires exhibited complete photocatalytic degradation of Rhodamine B within 45 min under visible light irradiation. The antibacterial activity of Ag/AgVO 3 nanowires was tested against Escherechia coli and Bacillus subtilis. The minimum growth inhibitory concentration value was found to be 50 and 10 folds lower than for the antibiotic ciprofloxacin for E. coli and B. subtilis, respectively. The antibacterial properties of the β-AgVO 3 nanorods prove that in case of the Ag dispersed Ag/AgVO 3 nanowires, the enhanced antibacterial action is also due to contribution from the AgVO 3 support

Studies on the effect of AgNP binding on α-amylase structure of porcine pancreas and Bacillus subtilis by multi-spectroscopic methods

International Nuclear Information System (INIS)

Ernest, Vinita; Sekar, Gajalakshmi; Mukherjee, Amitava; Chandrasekaran, N.

2014-01-01

Functionalizing silver nanoparticles (AgNPs) with biomolecules have a number of applications in catalysis, sensing, pharmaceutics and therapy. For the first time, herein we report the interaction of amylase-AgNPs through various spectroscopic techniques. AgNPs are synthesized and characterized by UV–vis spectroscopy, transmission electron microscopy (TEM) and Dynamic Light Scattering (DLS). The binding of AgNPs to α-amylase are investigated by UV–vis, fluorescence, circular dichroism and FTIR spectroscopic techniques. Absorption intensity and Stern–Volmer plots confirmed the formation of the ground state complex with AgNPs. The quenching of the intrinsic protein fluorescence in the presence of different concentrations of AgNP was observed. The apparent binding constant (K) and number of binding sites (n) was calculated from the Stern–Volmer plot was found to be 4.92×10 3 , 3.8×10 3 and 1.57, 1.3 for porcine pancreas and Bacillus subtilis α-amylase, respectively. Far-UV CD studies revealed the characteristic dichoric band at 222 nm for α-helical structure was shifted to 215 nm in porcine pancreatic α-amylase upon AgNP binding. Further, structural conformation change with peak shifts and the possible binding residues was confirmed through FTIR spectroscopy. -- Highlights: • AgNPs were synthesized using modified Creighton's method and characterized. • Structural changes analyzed by UV–vis, fluorescence spectroscopy. • CD and FTIR spectra reveal the secondary structure conformation change. • Potential application in food industry

Studies on the effect of AgNP binding on α-amylase structure of porcine pancreas and Bacillus subtilis by multi-spectroscopic methods

Energy Technology Data Exchange (ETDEWEB)

Ernest, Vinita; Sekar, Gajalakshmi; Mukherjee, Amitava; Chandrasekaran, N., E-mail: nchandrasekaran@vit.ac.in

2014-02-15

Functionalizing silver nanoparticles (AgNPs) with biomolecules have a number of applications in catalysis, sensing, pharmaceutics and therapy. For the first time, herein we report the interaction of amylase-AgNPs through various spectroscopic techniques. AgNPs are synthesized and characterized by UV–vis spectroscopy, transmission electron microscopy (TEM) and Dynamic Light Scattering (DLS). The binding of AgNPs to α-amylase are investigated by UV–vis, fluorescence, circular dichroism and FTIR spectroscopic techniques. Absorption intensity and Stern–Volmer plots confirmed the formation of the ground state complex with AgNPs. The quenching of the intrinsic protein fluorescence in the presence of different concentrations of AgNP was observed. The apparent binding constant (K) and number of binding sites (n) was calculated from the Stern–Volmer plot was found to be 4.92×10{sup 3}, 3.8×10{sup 3} and 1.57, 1.3 for porcine pancreas and Bacillus subtilis α-amylase, respectively. Far-UV CD studies revealed the characteristic dichoric band at 222 nm for α-helical structure was shifted to 215 nm in porcine pancreatic α-amylase upon AgNP binding. Further, structural conformation change with peak shifts and the possible binding residues was confirmed through FTIR spectroscopy. -- Highlights: • AgNPs were synthesized using modified Creighton's method and characterized. • Structural changes analyzed by UV–vis, fluorescence spectroscopy. • CD and FTIR spectra reveal the secondary structure conformation change. • Potential application in food industry.

Cloning analysis of HBV-specific CD8 T cell receptor gene in patients with acute hepatitis B

Directory of Open Access Journals (Sweden)

Ning DING

2011-05-01

Full Text Available Objective To investigate the molecular mechanism of T cell receptor(TCR in CD8 T cell-mediated immune response to HBV in patients with acute hepatitis B(AHB.Methods Peripheral blood mononuclear cells(PBMCs were collected from HLA-A2-positive AHB patients.To determine HBsAg183-191 and HBsAg335-343-specific CD8 T cell frequencies,the PBMCs were stained by fluorescence-labeled anti-CD3,anti-CD8 and pentamers,and analyzed by flow cytometry.PBMCs from 6 patients were stimulated with epitopic peptide HBsAg335-343 in vitro for 3 to 4 weeks.HBV-specific CD8 T cells were isolated by magnetic activated cell sorting followed by flow florescence activated cell sorting.The mRNA of sorted cells was extracted after expanding by IL-2,anti-CD3 and anti-CD8.The full-length gene fragments of variable region of TCR α and β chains were gained by 5’-RACE,and then cloned and sequenced(≥50 clones for single chain of each sample.The gene families of TCR α and β chains were identified and the sequence characters of CDR3 were compared.Results Analysis of more than 600 cloned gene sequences of TCR α and β chains showed that the proliferated HBV-specific CD8 T cells from 6 AHB patients presented a predominant expression in TCR α and chains,with 2-4 α chain families and 1-4 chain families in each case.The α2,α14,α15,β3,β13 and 23 families were detected in more than one case.The chain genes were all 13 for all tested clones in one case.For the same α chain or-chain family,CDR3 sequences tended to be identical in one case but different among cases.Conclusions HBV-specific CD8 T cells with antigenic peptide-induced proliferation present predominance in the usage of TCR α and β chains.This property might be one of the important molecular factors influencing anti-HBV immunity.

Effects of trace elements on urease activity in soils

Energy Technology Data Exchange (ETDEWEB)

Tabatabai, M A

1977-01-01

Disposal of sewage sludges and effluents on agricultural land is becoming a widespread practice. Most sludge samples disposed on soils contain large quantities of various trace elements. Studies of 20 trace elements commonly found in sludge samples showed that they inhibit the activity of urease in soils and that their order of effectiveness as inhibitors of urease depends on the soil. When the trace elements were compared by using 5 ..mu..mol . g/sup -1/ soil, however, some of them showed the same order of effectiveness as urease inhibitors in the six soils studied i.e., for the monovalent and divalent ions. Ag/sup +/ greater than or equal to Hg/sup 2 +/ > Cu/sup 2 +/ > Cd/sup 2 +/ > Zn/sup 2 +/ > Sn/sup 2 +/ > Mn/sup 2 +/, and generally, Fe/sup 3 +/ > Fe/sup 2 +/ and Cu/sup 2 +/ > Cu/sup +/. Other trace element ions that inhibited urease were Ni/sup 2 +/, Co/sup 2 +/, Pb/sup 2 +/, Ba/sup 2 +/, As/sup 3 +/, B/sup 3 +/, Cr/sup 3 +/, Al/sup 3 +/, V/sup 4 +/, Se/sup 4 +/, and Mo/sup 6 +/. Of the trace element ions studied, only As/sup 5 +/ and W/sup 6 +/ did not inhibit urease activity in soils. Studies on the distribution of urease activity showed that it is concentrated in surface soils and decreases with depth. Urease activity was proportional to organic C distribution in each soil profile and was significantly correlated with organic C in the surface soils studied.

The potential effect of metallothionein 2A - 5 A/G single nucleotide polymorphism on blood cadmium, lead, zinc and copper levels

International Nuclear Information System (INIS)

Kayaalti, Zeliha; Aliyev, Vugar; Soeylemezoglu, Tuelin

2011-01-01

Metallothioneins (MTs) are low molecular weight, cysteine-rich, metal-binding proteins. Because of their rich thiol groups, MTs bind to the biologically essential metals and perform these metals' homeostatic regulations; absorb the heavy metals and assist with their transportation and extraction. The aim of this study was to investigate the association between the metallothionein 2A (MT2A) core promoter region - 5 A/G single nucleotide polymorphism (SNP) and Cd, Pb, Zn and Cu levels in the blood samples. MT2A polymorphism was determined by the standard polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique using the 616 blood samples and the genotype frequencies were found as 86.6% homozygote typical (AA), 12.8% heterozygote (AG) and 0.6% homozygote atypical (GG). Metal levels were analyzed by dual atomic absorption spectrophotometer system and the average levels of Cd, Pb, Zn and Cu in the blood samples were 1.69 ± 1.57 ppb, 30.62 ± 14.13 ppb, 0.98 ± 0.49 ppm and 1.04 ± 0.45 ppm, respectively. As a result; highly statistically significant associations were detected between the - 5 A/G core promoter region SNP in the MT2A gene and Cd, Pb and Zn levels (p = 0.004, p = 0.012 and p = 0.002, respectively), but no association was found with Cu level (p = 0.595). Individuals with the GG genotype had statistically lower Zn level and higher Cd and Pb levels in the blood samples than individuals with AA and AG genotypes. This study suggests that having the GG genotype individuals may be more sensitive for the metal toxicity and they should be more careful about protecting their health against the toxic effects of the heavy metals. - Highlights: → MT2A -5A/G SNP has strong effect on the Cd, Pb and Zn levels in the blood. → MT2A GG individuals should be more careful for their health against metal toxicity. → This SNP might be considered as a biomarker for risk of disease related to metals.

HIV-1 Infection of Primary CD4+ T Cells Regulates the Expression of Specific Human Endogenous Retrovirus HERV-K (HML-2) Elements.

Science.gov (United States)

Young, George R; Terry, Sandra N; Manganaro, Lara; Cuesta-Dominguez, Alvaro; Deikus, Gintaras; Bernal-Rubio, Dabeiba; Campisi, Laura; Fernandez-Sesma, Ana; Sebra, Robert; Simon, Viviana; Mulder, Lubbertus C F

2018-01-01

Endogenous retroviruses (ERVs) occupy extensive regions of the human genome. Although many of these retroviral elements have lost their ability to replicate, those whose insertion took place more recently, such as the HML-2 group of HERV-K elements, still retain intact open reading frames and the capacity to produce certain viral RNA and/or proteins. Transcription of these ERVs is, however, tightly regulated by dedicated epigenetic control mechanisms. Nonetheless, it has been reported that some pathological states, such as viral infections and certain cancers, coincide with ERV expression, suggesting that transcriptional reawakening is possible. HML-2 elements are reportedly induced during HIV-1 infection, but the conserved nature of these elements has, until recently, rendered their expression profiling problematic. Here, we provide comprehensive HERV-K HML-2 expression profiles specific for productively HIV-1-infected primary human CD4 + T cells. We combined enrichment of HIV-1 infected cells using a reporter virus expressing a surface reporter for gentle and efficient purification with long-read single-molecule real-time sequencing. We show that three HML-2 proviruses-6q25.1, 8q24.3, and 19q13.42-are upregulated on average between 3- and 5-fold in HIV-1-infected CD4 + T cells. One provirus, HML-2 12q24.33, in contrast, was repressed in the presence of active HIV replication. In conclusion, this report identifies the HERV-K HML-2 loci whose expression profiles differ upon HIV-1 infection in primary human CD4 + T cells. These data will help pave the way for further studies on the influence of endogenous retroviruses on HIV-1 replication. IMPORTANCE Endogenous retroviruses inhabit big portions of our genome. Moreover, although they are mainly inert, some of the evolutionarily younger members maintain the ability to express both RNA and proteins. We have developed an approach using long-read single-molecule real-time (SMRT) sequencing that produces long reads that

HLA Class II Defects in Burkitt Lymphoma: Bryostatin-1-Induced 17 kDa Protein Restores CD4+ T-Cell Recognition

Directory of Open Access Journals (Sweden)

Azim Hossain

2011-01-01

Full Text Available While the defects in HLA class I-mediated Ag presentation by Burkitt lymphoma (BL have been well documented, CD4+ T-cells are also poorly stimulated by HLA class II Ag presentation, and the reasons underlying this defect(s have not yet been fully resolved. Here, we show that BL cells are deficient in their ability to optimally stimulate CD4+ T cells via the HLA class II pathway. The observed defect was not associated with low levels of BL-expressed costimulatory molecules, as addition of external co-stimulation failed to result in BL-mediated CD4+ T-cell activation. We further demonstrate that BL cells express the components of the class II pathway, and the defect was not caused by faulty Ag/class II interaction, because antigenic peptides bound with measurable affinity to BL-associated class II molecules. Treatment of BL with broystatin-1, a potent modulator of protein kinase C, led to significant improvement of functional class II Ag presentation in BL. The restoration of immune recognition appeared to be linked with an increased expression of a 17 kDa peptidylprolyl-like protein. These results demonstrate the presence of a specific defect in HLA class II-mediated Ag presentation in BL and reveal that treatment with bryostatin-1 could lead to enhanced immunogenicity.

An electrochemical sensor for determining elemental iodine in gas media

Energy Technology Data Exchange (ETDEWEB)

Goffman, V.G.; Shaimerdinov, B.U.; Kotelkin, I.M. [Institute of New Chemical Problems, Moscow (Russian Federation)] [and others

1993-12-01

The possibility of using solid-electrolyte Ag, AgI/AgI/Au cells as sensors for determining the concentration of elemental iodine in gas media is investigated. It is established that the sensor parameters are independent of oxygen content and radiation dose at different relative humidities.

CD83 Antibody Inhibits Human B Cell Responses to Antigen as well as Dendritic Cell-Mediated CD4 T Cell Responses.

Science.gov (United States)

Wong, Kuan Y; Baron, Rebecca; Seldon, Therese A; Jones, Martina L; Rice, Alison M; Munster, David J

2018-05-15

Anti-CD83 Ab capable of Ab-dependent cellular cytotoxicity can deplete activated CD83 + human dendritic cells, thereby inhibiting CD4 T cell-mediated acute graft-versus-host disease. As CD83 is also expressed on the surface of activated B lymphocytes, we hypothesized that anti-CD83 would also inhibit B cell responses to stimulation. We found that anti-CD83 inhibited total IgM and IgG production in vitro by allostimulated human PBMC. Also, Ag-specific Ab responses to immunization of SCID mice xenografted with human PBMC were inhibited by anti-CD83 treatment. This inhibition occurred without depletion of all human B cells because anti-CD83 lysed activated CD83 + B cells by Ab-dependent cellular cytotoxicity and spared resting (CD83 - ) B cells. In cultured human PBMC, anti-CD83 inhibited tetanus toxoid-stimulated B cell proliferation and concomitant dendritic cell-mediated CD4 T cell proliferation and expression of IFN-γ and IL-17A, with minimal losses of B cells (80% of B cells but had no effect on CD4 T cell proliferation and cytokine expression. By virtue of the ability of anti-CD83 to selectively deplete activated, but not resting, B cells and dendritic cells, with the latter reducing CD4 T cell responses, anti-CD83 may be clinically useful in autoimmunity and transplantation. Advantages might include inhibited expansion of autoantigen- or alloantigen-specific B cells and CD4 T cells, thus preventing further production of pathogenic Abs and inflammatory cytokines while preserving protective memory and regulatory cells. Copyright © 2018 by The American Association of Immunologists, Inc.

Preparation and antibacterial activities of Ag/Ag+/Ag3+ nanoparticle composites made by pomegranate (Punica granatum rind extract

Directory of Open Access Journals (Sweden)

Hui Yang

Full Text Available Nano-silver and its composite materials are widely used in medicine, food and other industries due to their strong conductivity, size effect and other special performances. So far, more microbial researches have been applied, but a plant method is rarely reported. In order to open up a new way to prepare AgNP composites, pomegranate peel extract was used in this work to reduce Ag+ to prepare Ag/Ag+/Ag3+ nanoparticle composites. UV–Vis was employed to detect and track the reduction of Ag+ and the forming process of AgNPs. The composition, structure and size of the crystal were analyzed by XRD and TEM. Results showed that, under mild conditions, pomegranate peel extract reacted with dilute AgNO3 solution to produce Ag/Ag+/Ag3+ nanoparticle composites. At pH = 8 and 10 mmol/L of AgNO3 concentration, the size of the achieved composites ranged between 15 and 35 nm with spherical shapes and good crystallinity. The bactericidal experiment indicated that the prepared Ag/Ag+/Ag3+ nanoparticles had strong antibacterial activity against gram positive bacteria and gram negative bacteria. FTIR analysis revealed that biological macromolecules with groups of NH2, OH, and others were distributed on the surface of the newly synthesized Ag/Ag+/Ag3+ nanoparticles. This provided a useful clue to further study the AgNP biosynthesis mechanism. Keywords: Pomegranate rind, Biosynthesis, Ag/Ag+/Ag3+ nanoparticle composites, Antibacterial activity

Distributions, sources and pollution status of 17 trace metal/metalloids in the street dust of a heavily industrialized city of central China

International Nuclear Information System (INIS)

Li, Zhonggen; Feng, Xinbin; Li, Guanghui; Bi, Xiangyang; Zhu, Jianming; Qin, Haibo; Dai, Zhihui; Liu, Jinling; Li, Qiuhua; Sun, Guangyi

2013-01-01

A series of representative street dust samples were collected from a heavily industrialized city, Zhuzhou, in central China, with the aim to investigate the spatial distribution and pollution status of 17 trace metal/metalloid elements. Concentrations of twelve elements (Pb, Zn, Cu, Cd, Hg, As, Sb, In, Bi, Tl, Ag and Ga) were distinctly amplified by atmospheric deposition resulting from a large scale Pb/Zn smelter located in the northwest fringe of the city, and followed a declining trend towards the city center. Three metals (W, Mo and Co) were enriched in samples very close to a hard alloy manufacturing plant, while Ni and Cr appeared to derive predominantly from natural sources. Other industries and traffic had neglectable effects on the accumulation of observed elements. Cd, In, Zn, Ag and Pb were the five metal/metalloids with highest pollution levels and the northwestern part of city is especially affected by heavy metal pollution. -- Highlights: •Large-scale Pb/Zn smelters contributed to elevated trace elements in the street dust. •The hard alloy processing caused the enrichment of a few elements. •Cd, In, Zn, Ag and Pb were the most polluted elements. •Northwestern Zhuzhou suffered severe contamination for a range of trace elements. -- Pb/Zn smelting and hard alloy processing operations have caused seriously contamination of trace metal/metalloids in the street dust

Aging Impairs the Ability of Conventional Dendritic Cells to Cross-Prime CD8+ T Cells upon Stimulation with a TLR7 Ligand.

Directory of Open Access Journals (Sweden)

Estefanía R Zacca

Full Text Available The aging process is accompanied by altered immune system functioning and an increased risk of infection. Dendritic cells (DCs are antigen-presenting cells that play a key role in both adaptive and innate immunity, but how aging affects DCs and their influence on immunity has not been thoroughly established. Here we examined the function of conventional DCs (cDCs in old mice after TLR7 stimulation, focusing on their ability to cross-prime CD8+ T cells. Using polyU, a synthetic ssRNA analog, as TLR7 ligand and OVA as an antigen (Ag model, we found that cDCs from old mice have a poor ability to stimulate a CD8+ T cell-mediated cytotoxic response. cDCs from old mice exhibit alterations in Ag-processing machinery and TLR7 activation. Remarkably, CD8α+ cDCs from old mice have an impaired ability to activate naïve CD8+ T cells and, moreover, a lower capacity to mature and to process exogenous Ag. Taken together, our results suggest that immunosenescence impacts cDC function, affecting the activation of naïve CD8+ T cells and the generation of effector cytotoxic T cells.

Transplantation of epiphytic bioaccumulators (Tillandsia capillaris) for high spatial resolution biomonitoring of trace elements and point sources deconvolution in a complex mining/smelting urban context

Science.gov (United States)

Goix, Sylvaine; Resongles, Eléonore; Point, David; Oliva, Priscia; Duprey, Jean Louis; de la Galvez, Erika; Ugarte, Lincy; Huayta, Carlos; Prunier, Jonathan; Zouiten, Cyril; Gardon, Jacques

2013-12-01

Monitoring atmospheric trace elements (TE) levels and tracing their source origin is essential for exposure assessment and human health studies. Epiphytic Tillandsia capillaris plants were used as bioaccumulator of TE in a complex polymetallic mining/smelting urban context (Oruro, Bolivia). Specimens collected from a pristine reference site were transplanted at a high spatial resolution (˜1 sample/km2) throughout the urban area. About twenty-seven elements were measured after a 4-month exposure, also providing new information values for reference material BCR482. Statistical power analysis for this biomonitoring mapping approach against classical aerosols surveys performed on the same site showed the better aptitude of T. Capillaris to detect geographical trend, and to deconvolute multiple contamination sources using geostatistical principal component analysis. Transplanted specimens in the vicinity of the mining and smelting areas were characterized by extreme TE accumulation (Sn > Ag > Sb > Pb > Cd > As > W > Cu > Zn). Three contamination sources were identified: mining (Ag, Pb, Sb), smelting (As, Sn) and road traffic (Zn) emissions, confirming results of previous aerosol survey.

Syntheses and crystal structures of BaAgTbS{sub 3}, BaCuGdTe{sub 3}, BaCuTbTe{sub 3}, BaAgTbTe{sub 3}, and CsAgUTe{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Prakash, Jai; Beard, Jessica C.; Ibers, James A. [Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113 (United States); Mesbah, Adel [Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113 (United States); ICSM-UMR 5257 CNRS/CEA/UM2/ENSCM, Bat 426, BP 17171, 30207 Bagnols/Ceze (France)

2015-06-15

Five new quaternary chalcogenides of the 1113 family, namely BaAgTbS{sub 3}, BaCuGdTe{sub 3}, BaCuTbTe{sub 3}, BaAgTbTe{sub 3}, and CsAgUTe{sub 3}, were synthesized by the reactions of the elements at 1173-1273 K. For CsAgUTe{sub 3} CsCl flux was used. Their crystal structures were determined by single-crystal X-ray diffraction studies. The sulfide BaAgTbS{sub 3} crystallizes in the BaAgErS{sub 3} structure type in the monoclinic space group C{sup 3},{sub 2h}-C2/m, whereas the tellurides BaCuGdTe{sub 3}, BaCuTbTe{sub 3}, BaAgTbTe{sub 3}, and CsAgUTe{sub 3} crystallize in the KCuZrS{sub 3} structure type in the orthorhombic space group D{sup 1},{sub 2}{sup 7},{sub h}-Cmcm. The BaAgTbS{sub 3} structure consists of edge-sharing [TbS{sub 6}{sup 9-}] octahedra and [AgS{sub 5}{sup 9-}] trigonal pyramids. The connectivity of these polyhedra creates channels that are occupied by Ba atoms. The telluride structure features {sup 2}{sub ∞}[MLnTe{sub 3}{sup 2-}] layers for BaCuGdTe{sub 3}, BaCuTbTe{sub 3}, BaAgTbTe{sub 3}, and {sup 2}{sub ∞}[AgUTe{sub 3}{sup 1-}] layers for CsAgUTe{sub 3}. These layers comprise [MTe{sub 4}] tetrahedra and [LnTe{sub 6}] or [UTe{sub 6}] octahedra. Ba or Cs atoms separate these layers. As there are no short Q..Q (Q = S or Te) interactions these compounds achieve charge balance as Ba{sup 2+}M{sup +}Ln{sup 3+}(Q{sup 2-}){sub 3} (Q = S and Te) and Cs{sup +}Ag{sup +}U{sup 4+}(Te{sup 2-}){sub 3}. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Determination of uranium isotopes (235U, 238U) and trace elements (Cd, Pb, Cu and As) in bottled drinking water by Icp-SFMS

International Nuclear Information System (INIS)

Lara A, N.; Hernandez M, H.; Romero G, E. T.; Kuri de la C, A.; Perez B, M. A.

2016-09-01

In the present work we propose an optimized method for the quantification of uranium isotopes ( 235 U, 2 38 U) and the elements Cd, Pb, Cu and As in bottled water for drinking at trace levels of concentration. Based on the multi-element detection capability, the high sensitivity and resolution that the Mass Spectrometry with Magnetic Sector with Inductively Coupled Plasma Source (Icp-SFMS) technique offers; the high, medium and low resolution analysis conditions for the elements under study were established and optimized using and Element 2/Xr equipment and the 23 multi-elemental Certified Reference Material (CRM). The analysis method was validated using the standard reference material Nist 1643d and CRM mono-elemental s as external standards for the quantification of the analytes. Samples, targets and CRM were acidified with 2% of HNO 3 and analyzed without pretreatment under the established analysis conditions. The results obtained show concentrations of 235 U, 238 U, 111 Cd, 208 Pb, 63 Cu and 75 As in the range of μg L -1 , the linearity obtained from the calibration curves for each element has correlation coefficients < 0.99 in all cases, the accuracy of the method in terms of percent relative standard deviation (RSD %) was less than 5%, the mean recovery rate of Nist 1643d ranged from 96.46% to 101.12%. The optimization of the method guarantees the stability and calibration of the equipment throughout the analysis, as well as the ability to resolve interferences. In conclusion, the method proposed using Icp-SFMS offers the advantages of being fast and simple for the multi-elemental analysis in water at trace levels, with low limits of quantification and detection, with good linearity, accuracy, precision and reproducibility to a degree of reliability of 95%. (Author)

The role of Ag precipitates in Cu-12 wt% Ag

Energy Technology Data Exchange (ETDEWEB)

Yao, D.W.; Song, L.N. [Department of Materials Science and Engineering, Zhejiang University, Zheda Road No.38, Hangzhou, Zhejiang 310027 (China); Dong, A.P.; Wang, L.T. [China Railway Construction Electrification Bureau Group Co.,Ltd., Beijing 100036 (China); Zhang, L. [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Meng, L., E-mail: mengliang@zju.edu.cn [Department of Materials Science and Engineering, Zhejiang University, Zheda Road No.38, Hangzhou, Zhejiang 310027 (China)

2012-12-15

The Cu-12 wt% Ag was prepared to investigate the role of Ag precipitates on the properties of the alloy. Two kinds of heat treatment procedures were adopted to produce different amount of Ag precipitates in the Cu-12 wt% Ag. The microstructure of Ag precipitates was systematically observed by optical microscopy and electron microscopy. The Cu-12 wt% Ag with more Ag precipitates exhibits higher strength and lower electrical conductivity. More Ag precipitates results in more phase interface and less Ag atoms dissolved in Cu matrix. By comparing the strengthening effect and electron scattering effect of phase interface and dissolved Ag atoms, it is conclude that the interface between Cu matrix and Ag precipitates could significantly block dislocation movement and enhance electron scattering in Cu-Ag alloys.

Long-term use of biosolids as organic fertilizers in agricultural soils: potentially toxic elements occurrence and mobility.

Science.gov (United States)

Marguí, E; Iglesias, M; Camps, F; Sala, L; Hidalgo, M

2016-03-01

The presence of potentially toxic elements (PTEs) may hinder a more widespread application of biosolids in agriculture. At present, the European Directive 86/278/CEE limit the total concentrations of seven metals (Cu, Cr, Ni, Pb, Zn, Cd and Hg) in agricultural soils and in sewage sludges used as fertilizers but it has not taken into consideration the potential impacts of other emerging micropollutants that may be present in the biosolids as well as their mobility. The aim of this study was to evaluate the accumulation and mobility of 13 elements (including regulated metals and other inorganic species) in agricultural soils repeatedly amended with biosolids for 15 years. Firstly, three digestions programs using different acid mixtures were tested to evaluate the most accurate and efficient method for analysis of soil and sludge. Results demonstrated that sewage sludge application increased concentrations of Pb and Hg in soil, but values did not exceed the quality standard established by legislation. In addition, other elements (As, Co, Sb, Ag, Se and Mn) that at present are not regulated by the Spanish and European directives were identified in the sewage sludge, and significant differences were found between Ag content in soils amended with biosolids in comparison with control soils. This fact can be related to the increasing use of silver nanoparticles in consumer products due to their antibacterial properties. Results from the leaching tests show up that, in general, the mobility degree for both regulated and non-regulated elements in soils amended with biosolids was quite low (<10 %).

Separation of no-carrier-added 107,109Cd from proton induced silver target. Classical chemistry still relevant

International Nuclear Information System (INIS)

Moumita Maiti; Susanta Lahiri; Tomar, B.S.

2011-01-01

The classical chemistry like precipitation technique is relevant even in modern days trans-disciplinary research from the view point of green chemistry. A definite demand of no-carrier-added (nca) cadmium tracers, namely, 107,109 Cd, has been realized for diverse applications. Development of efficient separation technique is therefore important to address the purity of the tracers for various applications. No-carrier-added 107,109 Cd radionuclides were produced by bombarding natural silver target matrix with 13 MeV protons, which gave ∼15 MBq/μA h yield for nca 107 Cd. The nca cadmium radionuclides were separated from the natural silver target matrix by precipitating Ag as AgCl. The developed method is an example wherein green chemistry is used in trans-disciplinary research. The method is also simple, fast, cost effective and environmentally benign. (author)

Noise properties of Pb/Cd-free thick film resistors

International Nuclear Information System (INIS)

Stadler, Adam Witold; Kolek, Andrzej; Zawislak, Zbigniew; Mleczko, Krzysztof; Jakubowska, Malgorzata; Kielbasinski, Konrad Rafal; Mlozniak, Anna

2010-01-01

Low-frequency noise spectroscopy has been used to examine noise properties of Pb/Cd-free RuO 2 - and CaRuO 3 -based thick films screen printed on alumina substrates. Experiments were performed in the temperature range 77-300 K and the frequency range 0.5-5000 Hz with multiterminal devices. The measured noise has been recognized as resistance noise that consists of background 1/f noise and components generated by several thermally activated noise sources (TANSs) of different activation energies. The total noise has been composed of the contributions generated in the resistive layer and in the resistive/conductive layers interface. These noise sources are non-uniformly distributed in the resistor volume. Noise intensity of new-resistive layers has been described by the noise parameter C bulk . Pb/Cd-free layers turned out to be noisier than their Pb-containing counterparts; however, the removal of Pb and Cd from resistive composition is hardly responsible for the increase in the noise. In the case of RuO 2 layers noise increases most likely due to larger grain size of RuO 2 powder used to prepare resistive pastes. Information on the quality of the resistive-to-conductive layers interface occurred to be stored in the values of noise parameter C int . Pb/Cd-free RuO 2 -based resistive pastes form well-behaved interfaces with various Ag-based conductive pastes. In contrast, CaRuO 3 -based paste forms bad contacts with AgPd terminations because the density of TANSs increases in the interface area.

Heterovalent Cation Substitutional and Interstitial Doping in Semiconductor Sensitizers for Quantum Dot Cosensitized Solar Cell

Directory of Open Access Journals (Sweden)

Ningning Zhang

2015-01-01

Full Text Available Doped films of TiO2/PbS/CdS have been prepared by successive ionic layer adsorption and reaction (SILAR method. Bi- and Ag-doped-PbS quantum dot (QD were produced by admixing Bi3+ or Ag+ during deposition and the existing forms of the doping element in PbS QD were analyzed. The results show that Bi3+ entered the cube space of PbS as donor yielding interstitial doping Bi-doped-PbS QD, while Ag+ replaced Pb2+ of PbS as acceptor yielding substitutional doping Ag-doped-PbS QD. The novel Bi-doped-PbS/CdS and Ag-doped-PbS/CdS quantum dot cosensitized solar cell (QDCSC were fabricated and power conversion efficiency (PCE of 2.4% and 2.2% was achieved, respectively, under full sun illumination.

Fabrication of Cu-Ag core-shell bimetallic superfine powders by eco-friendly reagents and structures characterization

International Nuclear Information System (INIS)

Zhao Jun; Zhang Dongming; Zhao Jie

2011-01-01

Superfine bimetallic Cu-Ag core-shell powders were synthesized by reduction of copper sulfate pentahydrate and silver nitrate with eco-friendly ascorbic acid as a reducing agent and cyclodextrins as a protective agent in an aqueous system. The influence of Ag/Cu ratio on coatings was investigated. Ag was homogeneously distributed on the surface of Cu particles at a mole ratio of Ag/Cu=1. FE-SEM showed an uniformity of Ag coatings on Cu particles. Antioxidation of Cu particles was improved by increasing Ag/Cu ratio. TEM-EDX and UV-vis spectra also revealed that Cu cores were covered by Ag nanoshells on the whole. The surface composition analysis by XPS indicated that only small parts of Cu atoms in the surface were oxidized. It was noted that the hindrance of cyclodextrins chemisorbed on particles plays an important role in forming high quality and good dispersity Cu-Ag (Cu-Ag) core-shell powders. - Graphical abstract: Mechanism of fabricating Cu-Ag particles with good dispersibility using β-CDs as a protective agent was studied because of its special structure. Highlights: → Green supramolecular β-CD used as a protective agent and ascorbic acid(Vc) as a reducing agent to fabricate Cu-Ag powders. → Particles are monodisperse and the diameter is close to nanoscale(100-150 nm). → Resistance of Cu particles to oxidation was higher. → Formation mechanism explained.

Amorphous Fe-B alloys in B-Fe-Ag multilayers studied by magnetization and Mössbauer measurements

DEFF Research Database (Denmark)

Kiss, L. F.; Balogh, J.; Bujdoso, L.

2011-01-01

Bulk and local magnetic properties were studied in [1 nm B + 1 nm 57Fe + x nm Ag]5, x = 1, 2, 4, 5 and 10, multilayer samples. Although Ag does not mix with either of the other two elements the magnetic properties of the multilayers are strongly influenced by the Ag thickness below x = 5, whereas...

Preparation and antibacterial activities of Ag/Ag+/Ag3+ nanoparticle composites made by pomegranate (Punica granatum) rind extract

Science.gov (United States)

Yang, Hui; Ren, Yan-yu; Wang, Tao; Wang, Chuang

Nano-silver and its composite materials are widely used in medicine, food and other industries due to their strong conductivity, size effect and other special performances. So far, more microbial researches have been applied, but a plant method is rarely reported. In order to open up a new way to prepare AgNP composites, pomegranate peel extract was used in this work to reduce Ag+ to prepare Ag/Ag+/Ag3+ nanoparticle composites. UV-Vis was employed to detect and track the reduction of Ag+ and the forming process of AgNPs. The composition, structure and size of the crystal were analyzed by XRD and TEM. Results showed that, under mild conditions, pomegranate peel extract reacted with dilute AgNO3 solution to produce Ag/Ag+/Ag3+ nanoparticle composites. At pH = 8 and 10 mmol/L of AgNO3 concentration, the size of the achieved composites ranged between 15 and 35 nm with spherical shapes and good crystallinity. The bactericidal experiment indicated that the prepared Ag/Ag+/Ag3+ nanoparticles had strong antibacterial activity against gram positive bacteria and gram negative bacteria. FTIR analysis revealed that biological macromolecules with groups of sbnd NH2, sbnd OH, and others were distributed on the surface of the newly synthesized Ag/Ag+/Ag3+ nanoparticles. This provided a useful clue to further study the AgNP biosynthesis mechanism.

Plasmonic Ag{sub 2}MoO{sub 4}/AgBr/Ag composite: Excellent photocatalytic performance and possible photocatalytic mechanism

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhongliao [College of Physics and Electronic Information, Anhui Key Laboratory of Energetic Materials, Huaibei Normal University, Huaibei, 235000 (China); Zhang, Jinfeng, E-mail: zjf_y2004@126.com [College of Physics and Electronic Information, Anhui Key Laboratory of Energetic Materials, Huaibei Normal University, Huaibei, 235000 (China); Lv, Jiali [College of Physics and Electronic Information, Anhui Key Laboratory of Energetic Materials, Huaibei Normal University, Huaibei, 235000 (China); Dai, Kai, E-mail: daikai940@chnu.edu.cn [College of Physics and Electronic Information, Anhui Key Laboratory of Energetic Materials, Huaibei Normal University, Huaibei, 235000 (China); Liang, Changhao [College of Physics and Electronic Information, Anhui Key Laboratory of Energetic Materials, Huaibei Normal University, Huaibei, 235000 (China); Key Laboratory of Materials Physics and Anhui Key Laboratory of Nanomaterials and Nanotechnology, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei, 230031 (China)

2017-02-28

Highlights: • Novel Ag{sub 2}MoO{sub 4}/AgBr/Ag photocatalyst was prepared. • Ag{sub 2}MoO{sub 4}/AgBr/Ag showed high photocatalytic activity. • Ag{sub 2}MoO{sub 4}/AgBr/Ag showed long reusable life. - Abstract: Plasmonic Ag{sub 2}MoO{sub 4}/AgBr/Ag composite is fabricated by in-situ ion exchange and reduction methods at room temperature. The samples are characterized by X-ray diffraction (XRD), UV–vis diffuse reflectance (DRS), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscope (SEM) and photoluminescence (PL) measurements. The results show that butterfly-like Ag{sub 2}MoO{sub 4} nanosheets served as the precursor, and Ag{sub 2}MoO{sub 4}/AgBr/Ag is formed in phase transformation with MoO{sub 4}{sup 2−} displaced by Br{sup −}. The ternary Ag{sub 2}MoO{sub 4}/AgBr/Ag composite photocatalysts show greatly enhanced photocatalytic activity in photodegrading methylene blue (MB) under visible light irradiation compared with AgBr and Ag{sub 2}MoO{sub 4}. The pseudo-first-order rate constant k{sub app} of Ag{sub 2}MoO{sub 4}/AgBr/Ag is 0.602 min{sup −1}, which is 11.6 and 18.3 times as high as that of AgBr and Ag{sub 2}MoO{sub 4}, respectively. Meanwhile, the efficiency of degradation still kept 90% after ten times cyclic experiments. Eventually, possible photocatalytic mechanism was proposed.

Semiconductor CdF₂:Ga and CdF₂:In Crystals as Media for Real-Time Holography

Directory of Open Access Journals (Sweden)

Alexander E. Angervaks

2012-05-01

Full Text Available Monocrystalline cadmium fluoride is a dielectric solid that can be converted into a semiconductor by doping with donor impurities and subsequent heating in the reduction atmosphere. For two donor elements, Ga and In, the donor (“shallow” state is a metastable one separated from the ground (“deep” state by a barrier. Photoinduced deep-to-shallow state transition underlies the photochromism of CdF₂:Ga and CdF₂:In. Real-time phase holograms are recorded in these crystals capable of following up optical processes in a wide frequency range. The features of photochromic transformations in CdF₂:Ga and CdF₂:In crystals as well as holographic characteristics of these media are discussed. Exemplary applications of CdF₂-based holographic elements are given.

ADP ribosyl-cyclases (CD38/CD157), social skills and friendship.

Science.gov (United States)

Chong, Anne; Malavasi, Fabio; Israel, Salomon; Khor, Chiea Chuen; Yap, Von Bing; Monakhov, Mikhail; Chew, Soo Hong; Lai, Poh San; Ebstein, Richard P

2017-04-01

Why some individuals seek social engagement while others shy away has profound implications for normal and pathological human behavior. Evidence suggests that oxytocin (OT), the paramount human social hormone, and CD38 that governs OT release, contribute to individual differences in social skills from intense social involvement to extreme avoidance that characterize autism. To explore the neurochemical underpinnings of sociality, CD38 expression of peripheral blood leukocytes (PBL) was measured in Han Chinese undergraduates. First, CD38 mRNA levels were correlated with lower Autism Quotient (AQ), indicating enhanced social skills. AQ assesses the extent of autistic-like traits including the propensity and dexterity needed for successful social engagement in the general population. Second, three CD157 eQTL SNPs in the CD38/CD157 gene region were associated with CD38 expression. CD157 is a paralogue of CD38 and is contiguous with it on chromosome 4p15. Third, association was also observed between the CD157 eQTL SNPs, CD38 expression and AQ. In the full model, CD38 expression and CD157 eQTL SNPs altogether account for a substantial 14% of the variance in sociality. Fourth, functionality of CD157 eQTL SNPs was suggested by a significant association with plasma oxytocin immunoreactivity products. Fifth, the ecological validity of these findings was demonstrated with subjects with higher PBL CD38 expression having more friends, especially for males. Furthermore, CD157 sequence variation predicts scores on the Friendship questionnaire. To summarize, this study by uniquely leveraging various measures reveals salient elements contributing to nonkin sociality and friendship, revealing a likely pathway underpinning the transition from normality to psychopathology. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fuel Element Mechanical Design for CAREM-25 Reactor

International Nuclear Information System (INIS)

Estevez, Esteban; Markiewicz, Mario; Gerding, Jose

2000-01-01

The Fuel Element mechanical design and spider-control reactivity and security rods assembly for the CAREM-25 reactor is introduced. The CAREM-25 Fuel Element has a hexagonal cross section with 127 positions, in a triangular arrangement.There are 108 positions for the fuel rods while the guide tubes and instrumentation tube occupy the 19 remaining positions.From the structural point of view, the fuel element is being composed by a framework formed by the guides and instrumentation tubes, 4 spacer grids and the upper and lower coupling pieces.The spider is a plane piece, with a central body and six radial branches in T form, which has holes where the absorber rods are fitted.The central body ends in a joint in the upper side, which allows connect the assembly whit the reactor control mechanisms.The absorber rods are made of a neutron absorber material (Ag-In-Cd) hermetically closed in a stainless steel cladding. In this work are determined, in addition to the basic design, the operational conditions, the functional requirements to be satisfied and in agreement with those, the adopted criteria and limits to avoid systematics failure during normal operation conditions. The proposed program for the verification and evaluation of design is detailed.To consolidate the design, a prototype was manufactures, based on drawings and specifications needed for its construction

Optimized elemental analysis of fluorescence lamp shredder waste.

Science.gov (United States)

Hobohm, Julia; Kuchta, Kerstin; Krüger, Oliver; van Wasen, Sebastian; Adam, Christian

2016-01-15

Fluorescence lamps contain considerable amounts of rare earth elements (REE). Several recycling procedures for REE recovery from spent lamps have been established. However, despite their economic importance, the respective recycling is scarce so far, with an REE recovery rate of less than 1%. A reliable analysis of REE and other relevant metals like Yttrium is crucial for a thorough and complete recovery process. This applies both to the solid matter and aqueous phase, since most of the recycling processes include wet-chemical steps. We tested seven different reagent mixtures for microwave-assisted digestion of fluorescent lamp shredder, including hydrofluoric acid, perchloric acid, and hydrogen peroxide. We determined the concentrations of 25 of the most relevant rare earth and other trace elements (Al, P, Ti, V, Cr, Fe, Ni, Cu, Ga, Ge, As, Y, Ag, Cd, Sn, Sb, La, Ce, Eu, Gd, Tb, W, Au, Hg, and Pb) in the respective dilutions. Two independent digestions, one a mixture of perchlorid/nitric/hydrofluoric acid and the other aqua regia, showed the highest concentrations of 23 of these elements, excluding only Sn and Tb. The REE concentrations in the tested lamp shredder sample (stated in g/kg) were 10.2 (Y), 12.1 (La), 7.77 (Ce), 6.91 (Eu), 1.90 (Gd), and 4.11 (Tb). Copyright © 2015 Elsevier B.V. All rights reserved.

Ag K- and L3-edge XAFS study on Ag species in Ag/Ga2O3 photocatalysts

International Nuclear Information System (INIS)

Yamamoto, M; Yamamoto, N; Yoshida, T; Nomoto, T; Yamamoto, A; Yoshida, H; Yagi, S

2016-01-01

Ag loaded Ga 2 O 3 (Ag/Ga 2 O 3 ) shows photocatalytic activity for reduction of CO 2 with water. Ag L 3 -edge XANES and K-edge EXAFS spectra were measured for various Ag/Ga 2 O 3 samples, which suggested that structural and chemical states of Ag species varied with the loading amount of Ag and the preparation method. The Ag species were metallic Ag particles with an AgGaO 2 -like interface structure in the sample with high loading amount of Ag while predominantly Ag metal clusters in the sample with low loading amount of Ag. The XANES feature just above the edge represented the interaction between the Ag species and the Ga 2 O 3 surface, showing that the Ag metal clusters had more electrons in the d -orbitals by interacting with the Ga 2 O 3 surface, which would contribute the high photocatalytic activity. (paper)

Cre-/IoxP-Mediated Recombination between the SIL and SCL Genes Leads to a Block in T-Cell Development at the CD4-CD8- to CD4+CD8+ Transition

Directory of Open Access Journals (Sweden)

Yue Cheng

2007-04-01

Full Text Available In the most common form of stem cell leukemia (SCL gene rearrangement, an interstitial deletion of 82 kb brings SCL under the control of regulatory elements that normally govern expression of the ubiquitously expressed SCL interrupting locus (SIL gene, which is located directly upstream of SCL. To investigate the effect of this fusion in a mouse model, a bacterial artificial chromosome (BAC clone containing both human SIL and SCL genes was isolated, and IoxP sites were inserted into intron 1 of both the SIL and SCL genes, corresponding to the sites at which recombination occurs in human T-cell acute lymphocytic leukemia patients. This BAC clone was used to generate transgenic SILIoxloxSCL mice. These transgenic mice were subsequently bred to Lck-Cre mice that express the Cre recombinase specifically in the thymus. The BAC transgene was recombined between the two IoxP sites in over 50% of the thymocytes from SILIoxloxSCL/Cre double-transgenic mice, bringing the SCL gene under the direct control of SIL regulatory elements. Aberrant SCL gene expression in the thymus was verified by reverse transcription- polymerase chain reaction. Using FACS analysis, we found that mice carrying both SILIoxloxSCL and Cre transgenes have increased CD4-/CD8- thymocytes compared with transgenenegative mice. In the spleen, these transgenic mice show a marked reduction in the number of mature CD4+ or CD8+ cells. These results demonstrate that conditional activation of SCL under control of SIL regulatory elements can impair normal T-cell development.

Human CD4+ T cells lyse target cells via granzyme/perforin upon circumvention of MHC class II restriction by an antibody-like immunoreceptor.

Science.gov (United States)

Hombach, Andreas; Köhler, Heike; Rappl, Gunter; Abken, Hinrich

2006-10-15

Immune elimination of tumor cells requires the close cooperation between CD8+ CTL and CD4+ Th cells. We circumvent MHC class II-restriction of CD4+ T cells by expression of a recombinant immunoreceptor with an Ab-derived binding domain redirecting specificity. Human CD4+ T cells grafted with an immunoreceptor specific for carcinoembryonic Ag (CEA) are activated to proliferate and secrete cytokines upon binding to CEA+ target cells. Notably, redirected CD4+ T cells mediate cytolysis of CEA+ tumor cells with high efficiencies. Lysis by redirected CD4+ T cells is independent of death receptor signaling via TNF-alpha or Fas, but mediated by perforin and granzyme because cytolysis is inhibited by blocking the release of cytotoxic granules, but not by blocking of Fas ligand or TNF-alpha. CD4+ T cells redirected by Ab-derived immunoreceptors in a MHC class II-independent fashion substantially extend the power of an adoptive, Ag-triggered immunotherapy not only by CD4+ T cell help, but also by cytolytic effector functions. Because cytolysis is predominantly mediated via granzyme/perforin, target cells that are resistant to death receptor signaling become sensitive to a cytolytic attack by engineered CD4+ T cells.

Precious metals and rare earth elements in municipal solid waste – Sources and fate in a Swiss incineration plant

Energy Technology Data Exchange (ETDEWEB)

Morf, Leo S., E-mail: leo.morf@bd.zh.ch [Baudirektion Kanton Zürich, Amt für Abfall, Wasser, Energie und Luft, Zurich (Switzerland); Gloor, Rolf; Haag, Olaf [Bachema AG, Schlieren (Switzerland); Haupt, Melanie [Zentrum für nachhaltige Abfall-und Ressourcennutzung ZAR, Hinwil (Switzerland); Skutan, Stefan [Bachema AG, Schlieren (Switzerland); Lorenzo, Fabian Di; Böni, Daniel [Zentrum für nachhaltige Abfall-und Ressourcennutzung ZAR, Hinwil (Switzerland)

2013-03-15

Highlights: ► We carefully addressed all the very valuable comments and suggestions of the reviewers. ► We also have shortened the size of the paper and tried simplify it substantially, as requested by the reviewers (introduction 25% reduced!). ► We have decided to take the chance and have replaced the data for the “additional” elements (Cu, Cd, Zn, Pb, Sn, Cr, Ni, Fe, Al) of the earlier MFA (Morf, 2011) with data that belong to the samples of this study. ► We are convinced that with the revision the paper has significantly improved in quality and attractiveness. - Abstract: In Switzerland many kinds of waste, e.g. paper, metals, electrical and electronic equipment are separately collected and recycled to a large extent. The residual amount of municipal solid waste (MSW) has to be thermally treated before final disposal. Efforts to recover valuable metals from incineration residues have recently increased. However, the resource potential of critical elements in the waste input (sources) and their partitioning into recyclable fractions and residues (fate) is unknown. Therefore, a substance flow analysis (SFA) for 31 elements including precious metals (Au, Ag), platinum metal group elements (Pt, Rh) and rare earth elements (La, Ce, etc.) has been conducted in a solid waste incinerator (SWI) with a state-of-the-art bottom ash treatment according to the Thermo-Re® concept. The SFA allowed the determination of the element partitioning in the SWI, as well as the elemental composition of the MSW by indirect analysis. The results show that the waste-input contains substantial quantities of precious metals, such as 0.4 ± 0.2 mg/kg Au and 5.3 ± 0.7 mg/kg Ag. Many of the valuable substances, such as Au and Ag are enriched in specific outputs (e.g. non-ferrous metal fractions) and are therefore recoverable. As the precious metal content in MSW is expected to rise due to its increasing application in complex consumer products, the results of this study are

Precious metals and rare earth elements in municipal solid waste – Sources and fate in a Swiss incineration plant

International Nuclear Information System (INIS)

Morf, Leo S.; Gloor, Rolf; Haag, Olaf; Haupt, Melanie; Skutan, Stefan; Lorenzo, Fabian Di; Böni, Daniel

2013-01-01

Highlights: ► We carefully addressed all the very valuable comments and suggestions of the reviewers. ► We also have shortened the size of the paper and tried simplify it substantially, as requested by the reviewers (introduction 25% reduced!). ► We have decided to take the chance and have replaced the data for the “additional” elements (Cu, Cd, Zn, Pb, Sn, Cr, Ni, Fe, Al) of the earlier MFA (Morf, 2011) with data that belong to the samples of this study. ► We are convinced that with the revision the paper has significantly improved in quality and attractiveness. - Abstract: In Switzerland many kinds of waste, e.g. paper, metals, electrical and electronic equipment are separately collected and recycled to a large extent. The residual amount of municipal solid waste (MSW) has to be thermally treated before final disposal. Efforts to recover valuable metals from incineration residues have recently increased. However, the resource potential of critical elements in the waste input (sources) and their partitioning into recyclable fractions and residues (fate) is unknown. Therefore, a substance flow analysis (SFA) for 31 elements including precious metals (Au, Ag), platinum metal group elements (Pt, Rh) and rare earth elements (La, Ce, etc.) has been conducted in a solid waste incinerator (SWI) with a state-of-the-art bottom ash treatment according to the Thermo-Re® concept. The SFA allowed the determination of the element partitioning in the SWI, as well as the elemental composition of the MSW by indirect analysis. The results show that the waste-input contains substantial quantities of precious metals, such as 0.4 ± 0.2 mg/kg Au and 5.3 ± 0.7 mg/kg Ag. Many of the valuable substances, such as Au and Ag are enriched in specific outputs (e.g. non-ferrous metal fractions) and are therefore recoverable. As the precious metal content in MSW is expected to rise due to its increasing application in complex consumer products, the results of this study are

Simultaneous Determination of 30 Trace Elements in Cancerous and Noncancerous Human Tissue Samples with Gamma-ray Spectrometry

Energy Technology Data Exchange (ETDEWEB)

Samsahl, K; Brune, D; Wester, P O

1963-10-15

The following trace elements were quantitatively determined by gamma-ray spectrometry in T samples of non-cancerous and 5 samples of cancerous human tissue: P, Ca, Cr, Fe, Co, Cu, Zn, As, Se, Br, Rb, Mo, Ag, Cd, Sb, Cs, La, Au, and Hg. In some of the samples the following elements were qualitatively determined: Ti+Sc, Ga, Sr, In, Ba, Ce, Hf, Os, Pt, and U. Most of the trace elements were found to be present in much higher concentrations in the non-cancerous than in the corresponding cancerous liver samples. In a typical run one sample each of cancerous and non-cancerous tissue was irradiated together with standards of the elements to be determined in a thermal flux of 2.10{sup 13} n/cm{sup 2}/sec. for 24 hours. The radioactive trace elements were separated into 16, and in some cases 18, groups by means of a chemical group separation method. Subsequently, the gamma spectrometric measurements were performed. Two persons can manage the chemical separations and measure the different activities from a run in 1,5 days. A new method of comparing unknown samples with standards was developed.

Synthesis and crystal structure of the new vanadate AgCaVO{sub 4}. Comparison with the arcanite structure

Energy Technology Data Exchange (ETDEWEB)

Nenert, Gwilherm [PANalytical B.V., Almelo (Netherlands)

2017-07-01

We report the synthesis and the crystal structure of the new vanadate AgCaVO{sub 4} from laboratory powder X-ray data. Contrary to the previously reported AgBVO{sub 4} (B=Mg, Cd), AgCaVO{sub 4} exhibits the arcanite structure (β-K{sub 2}SO{sub 4}). Although it exhibits the same structure than arcanite, significant differences are observed. These differences are explained by deriving the atomic displacement field. The change of connectivity within the structure between β-K{sub 2}SO{sub 4} and AgCaVO{sub 4} results from a rotation of the VO{sub 4} tetrahedra giving rise to a change from a face sharing to an edge sharing octahedral chains. Additionally, the thermal expansion of AgCaVO{sub 4} has been investigated up to 800 C.

Abundance, distribution and bioavailability of major and trace elements in surface sediments from the Cai River estuary and Nha Trang Bay (South China Sea, Vietnam)

Science.gov (United States)

Koukina, S. E.; Lobus, N. V.; Peresypkin, V. I.; Dara, O. M.; Smurov, A. V.

2017-11-01

Major (Si, Al, Fe, Ti, Mg, Ca, Na, K, S, P), minor (Mn) and trace (Li, V, Cr, Co, Ni, Cu, Zn, As, Sr, Zr, Mo, Cd, Ag, Sn, Sb, Cs, Ba, Hg, Pb, Bi and U) elements, their chemical forms and the mineral composition, organic matter (TOC) and carbonates (TIC) in surface sediments from the Cai River estuary and Nha Trang Bay were first determined along the salinity gradient. The abundance and ratio of major and trace elements in surface sediments are discussed in relation to the mineralogy, grain size, depositional conditions, reference background and SQG values. Most trace-element contents are at natural levels and are derived from the composition of rocks and soils in the watershed. A severe enrichment of Ag is most likely derived from metal-rich detrital heavy minerals such as Ag-sulfosalts. Along the salinity gradient, several zones of metal enrichment occur in surface sediments because of the geochemical fractionation of the riverine material. The parts of actually and potentially bioavailable forms (isolated by four single chemical reagent extractions) are most elevated for Mn and Pb (up to 36% and 32% of total content, respectively). The possible anthropogenic input of Pb in the region requires further study. Overall, the most bioavailable parts of trace elements are associated with easily soluble amorphous Fe and Mn oxyhydroxides. The sediments are primarily enriched with bioavailable metal forms in the riverine part of the estuary. Natural (such as turbidities) and human-generated (such as urban and industrial activities) pressures are shown to influence the abundance and speciation of potential contaminants and therefore change their bioavailability in this estuarine system.

Visible light driven photocatalysis and antibacterial activity of AgVO{sub 3} and Ag/AgVO{sub 3} nanowires

Energy Technology Data Exchange (ETDEWEB)

Singh, Anamika [Department of Life Sciences, University of Mumbai, Santacruz (E), Mumbai 400 098 (India); Dutta, Dimple P., E-mail: dimpled@barc.gov.in [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Ballal, A. [Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Tyagi, A.K. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Fulekar, M.H. [School of Environment and Sustainable Development, Central University of Gujarat, Gandhinagar 382 030, Gujarat (India)

2014-03-01

Graphical abstract: - Highlights: • Ag/AgVO{sub 3} and pure AgVO{sub 3} nanowires synthesized by sonochemical process. • Characterization done using XRD, SEM, TEM, EDX and BET analysis. • Visible light degradation of RhB by Ag/AgVO{sub 3} within 45 min. • Antibacterial activity of Ag/AgVO{sub 3} demonstrated. - Abstract: Ag/AgVO{sub 3} nanowires and AgVO{sub 3} nanorods were synthesized in aqueous media via a facile sonochemical route. The as-synthesized products were characterized by X-ray diffraction, Brunauer–Emmett–Teller surface area analysis, scanning electron microscopy together with an energy dispersion X-ray spectrum analysis, transmission electron microscopy and UV–vis diffuse reflectance spectroscopy. The results revealed that inert atmosphere promotes the formation of Ag/AgVO{sub 3} nanowires. The photocatalytic studies revealed that the Ag/AgVO{sub 3} nanowires exhibited complete photocatalytic degradation of Rhodamine B within 45 min under visible light irradiation. The antibacterial activity of Ag/AgVO{sub 3} nanowires was tested against Escherechia coli and Bacillus subtilis. The minimum growth inhibitory concentration value was found to be 50 and 10 folds lower than for the antibiotic ciprofloxacin for E. coli and B. subtilis, respectively. The antibacterial properties of the β-AgVO{sub 3} nanorods prove that in case of the Ag dispersed Ag/AgVO{sub 3} nanowires, the enhanced antibacterial action is also due to contribution from the AgVO{sub 3} support.

Synthesis of CdS nanoparticles quantum dots capped by 2,2′-dithiodibenzoic acid and study of its interaction with some transition metal ions

International Nuclear Information System (INIS)

Hosseini, Mohammad Saeid; Jahanbani, Hamideh

2013-01-01

In this work, CdS quantum dots (QDs) capped by 2,2′-dithiodibenzoic acid (DDBA) were prepared at one step. The size, shape, components and spectral properties of DDBA-capped-CdS QDs were characterized by transmission electron microscopy, infrared spectrometry and spectroflourometry. The results showed that the prepared QDs with an average diameter of 15 nm have a favorable fluorescence, which is highly affected by pH of the environment. Interaction of some heavy metal ions including Ag(I), Hg(II), Cu(II), Fe(II), Ni(II), pb(II), Mn(II), Zn(II) and Co(II) with DDBA-capped-CdS QDs was investigated at different buffering pH media. Based on the fluorescence quenching of the QDs in the presence of metal ion of interest, feasibility of their determinations were examined according to the Stern–Volmer equation. The investigations showed that Ag(I) ions can be determined in the presence of many co-existence metal ions at the buffering pH of 7. This method was then applied for Ag(I) measurement in some environmental samples, satisfactorily. -- Highlights: ► A new CdS quantum dot capped with 2,2′-dithiodibenzoic acid (DDBA) was prepared. ► The prepared QDs benefit from a favorable fluorescence. ► Interaction of some metal ions with the QDs was examined according to the Stern–Volmer equation. ► The determination of Ag(I) is feasible in the presence of many co-existence metal ions. ► The method benefits from high-speed and considerable simplicity for Ag(I) determination

Enhanced device performances of a new inverted top-emitting OLEDs with relatively thick Ag electrode.

Science.gov (United States)

Park, So-Ra; Suh, Min Chul

2018-02-19

To improve the device performances of top-emitting organic light emitting diodes (TEOLEDs), we developed a new inverted TEOLEDs structure with silver (Ag) metal as a semi-transparent top electrode. Especially, we found that the use of relatively thick Ag electrode without using any carrier injection layer is beneficial to realize highly efficient device performances. Also, we could insert very thick overlying hole transport layer (HTL) on the emitting layer (EML) which could be very helpful to suppress the surface plasmon polariton (SPP) coupling if it is applied to the common bottom-emission OLEDs (BEOLEDs). As a result, we could realize noteworthy high current efficiency of approximately ~188.1 cd/A in our new inverted TEOLEDs with 25 nm thick Ag electrode.

Investigations on structural, vibrational, morphological and optical properties of CdS and CdS/Co films by ultrasonic spray pyrolysis

International Nuclear Information System (INIS)

Aksay, S.; Polat, M.; Ozer, T.; Koese, S.; Guerbuez, G.

2011-01-01

CdS and CdS/Co films have been deposited on glass substrates by an ultrasonic spray pyrolysis method. The effects of Co incorporation on the structural, optical, morphological, elemental and vibrational properties of these films were investigated. XRD analysis confirmed the hexagonal wurtzite structure of all films and had no impurity phase. While CdS film has (0 0 2) as the preferred orientation, CdS/Co films have (1 1 0) as the preferred orientation. The direct optical band gap was found to decrease from 2.42 to 2.39 eV by Co incorporation. The decrease of the direct energy gaps by increasing Co contents is mainly due to the sp-d exchange interaction between the localized d-electrons of Co 2+ ions and band electrons of CdS. After the optical investigations, it was seen that the transmittance of CdS films decreased by Co content. The Raman measurements revealed two peaks corresponding to the 1LO and 2LO modes of hexagonal CdS. The vibrational modes of Cd-S were obtained in the wavenumber range (590-715 cm -1 ) using Fourier transform infrared spectroscopy (FTIR). The elemental analysis of the film was done by energy dispersive X-ray spectrometry.

Investigations on structural, vibrational, morphological and optical properties of CdS and CdS/Co films by ultrasonic spray pyrolysis

Science.gov (United States)

Aksay, S.; Polat, M.; Özer, T.; Köse, S.; Gürbüz, G.

2011-09-01

CdS and CdS/Co films have been deposited on glass substrates by an ultrasonic spray pyrolysis method. The effects of Co incorporation on the structural, optical, morphological, elemental and vibrational properties of these films were investigated. XRD analysis confirmed the hexagonal wurtzite structure of all films and had no impurity phase. While CdS film has (0 0 2) as the preferred orientation, CdS/Co films have (1 1 0) as the preferred orientation. The direct optical band gap was found to decrease from 2.42 to 2.39 eV by Co incorporation. The decrease of the direct energy gaps by increasing Co contents is mainly due to the sp-d exchange interaction between the localized d-electrons of Co2+ ions and band electrons of CdS. After the optical investigations, it was seen that the transmittance of CdS films decreased by Co content. The Raman measurements revealed two peaks corresponding to the 1LO and 2LO modes of hexagonal CdS. The vibrational modes of Cd-S were obtained in the wavenumber range (590-715 cm-1) using Fourier transform infrared spectroscopy (FTIR). The elemental analysis of the film was done by energy dispersive X-ray spectrometry.

Thermochemical properties of silver tellurides including empressite (AgTe) and phase diagrams for Ag-Te and Ag-Te-O

Science.gov (United States)

Voronin, Mikhail V.; Osadchii, Evgeniy G.; Brichkina, Ekaterina A.

2017-10-01

This study compiles original experimental and literature data on the thermodynamic properties (ΔfG°, S°, ΔfH°) of silver tellurides (α-Ag2Te, β-Ag2Te, Ag1.9Te, Ag5Te3, AgTe) obtained by the method of solid-state galvanic cell with the RbAg4I5 and AgI solid electrolytes. The thermodynamic data for empressite (AgTe, pure fraction from Empress Josephine Mine, Colorado USA) have been obtained for the first time by the electrochemical experiment with the virtual reaction Ag + Te = AgTe. The Ag-Te phase diagrams in the T - x and log fTe2 (gas) - 1/ T coordinates have been refined, and the ternary Ag-Te-O diagrams with Ag-Te-TeO2 (paratellurite) composition range have been calculated.

Heavy metal and trace elements in riparian vegetation and macrophytes associated with lacustrine systems in Northern Patagonia Andean Range.

Science.gov (United States)

Juárez, Andrea; Arribére, María A; Arcagni, Marina; Williams, Natalia; Rizzo, Andrea; Ribeiro Guevara, Sergio

2016-09-01

Vegetation associated with lacustrine systems in Northern Patagonia was studied for heavy metal and trace element contents, regarding their elemental contribution to these aquatic ecosystems. The research focused on native species and exotic vascular plant Salix spp. potential for absorbing heavy metals and trace elements. The native species studied were riparian Amomyrtus luma, Austrocedrus chilensis, Chusquea culeou, Desfontainia fulgens, Escallonia rubra, Gaultheria mucronata, Lomatia hirsuta, Luma apiculata, Maytenus boaria, Myrceugenia exsucca, Nothofagus antarctica, Nothofagus dombeyi, Schinus patagonicus, and Weinmannia trichosperma, and macrophytes Hydrocotyle chamaemorus, Isöetes chubutiana, Galium sp., Myriophyllum quitense, Nitella sp. (algae), Potamogeton linguatus, Ranunculus sp., and Schoenoplectus californicus. Fresh leaves were analyzed as well as leaves decomposing within the aquatic bodies, collected from lakes Futalaufquen and Rivadavia (Los Alerces National Park), and lakes Moreno and Nahuel Huapi (Nahuel Huapi National Park). The elements studied were heavy metals Ag, As, Cd, Hg, and U, major elements Ca, K, and Fe, and trace elements Ba, Br, Co, Cr, Cs, Hf, Na, Rb, Se, Sr, and Zn. Geochemical tracers La and Sm were also determined to evaluate contamination of the biological tissues by geological particulate (sediment, soil, dust) and to implement concentration corrections.

Gap junctions at the dendritic cell-T cell interface are key elements for antigen-dependent T cell activation.

Science.gov (United States)

Elgueta, Raul; Tobar, Jaime A; Shoji, Kenji F; De Calisto, Jaime; Kalergis, Alexis M; Bono, Maria R; Rosemblatt, Mario; Sáez, Juan C

2009-07-01

The acquired immune response begins with Ag presentation by dendritic cells (DCs) to naive T cells in a heterocellular cell-cell contact-dependent process. Although both DCs and T cells are known to express connexin43, a gap junction protein subunit, the role of connexin43 on the initiation of T cell responses remains to be elucidated. In the present work, we report the formation of gap junctions between DCs and T cells and their role on T cell activation during Ag presentation by DCs. In cocultures of DCs and T cells, Lucifer yellow microinjected into DCs is transferred to adjacent transgenic CD4(+) T cells, only if the specific antigenic peptide was present at least during the first 24 h of cocultures. This dye transfer was sensitive to gap junction blockers, such as oleamide, and small peptides containing the extracellular loop sequences of conexin. Furthermore, in this system, gap junction blockers drastically reduced T cell activation as reflected by lower proliferation, CD69 expression, and IL-2 secretion. This lower T cell activation produced by gap junction blockers was not due to a lower expression of CD80, CD86, CD40, and MHC-II on DCs. Furthermore, gap junction blocker did not affect polyclonal activation of T cell induced with anti-CD3 plus anti-CD28 Abs in the absence of DCs. These results strongly suggest that functional gap junctions assemble at the interface between DCs and T cells during Ag presentation and that they play an essential role in T cell activation.

Silver contents and Cu/Ag ratios in Martian meteorites and the implications for planetary differentiation

Science.gov (United States)

Wang, Zaicong; Becker, Harry

2017-11-01

mantle compared to bulk Mars. Bulk Mars is richer in moderately volatile elements than Earth, however, the Martian mantle displays a much stronger depletion of the moderately volatile elements Cu and Ag, e.g., by a factor of 15 for Cu. This observation is consistent with experimental studies suggesting that core formation at low P-T conditions on Mars led to more siderophile behavior of Cu and Ag than at high P-T conditions as proposed for Earth. In contrast, Cu/Ag ratios of the mantles of Mars and Earth (Cu/AgEarth = 3500 ± 1000) display only a difference by a factor of 3, which implies restricted fractionation of Cu and Ag even at high P-T conditions. The concentration data support the notion that siderophile element partitioning during planetary core formation scales with the size of the planetary body, which is particularly important for the differentiation of large terrestrial planets such as Earth. Collectively, the Ag and Cu data on magmatic products from the mantles of Mars and Earth and the data on chondrites confirm experimental predictions and support the limited fractionation of Cu and Ag during planetary core formation and high-temperature magmatic evolution, and probably also in early solar nebular processes.

Photoelectrochemical detection of copper ions by modulating the growth of CdS quantum dots.

Science.gov (United States)

Grinyte, Ruta; Barroso, Javier; Díez-Buitrago, Beatriz; Saa, Laura; Möller, Marco; Pavlov, Valeri

2017-09-15

We discovered that copper ions (Cu 2+ ) catalyze the oxidation of cysteine (CSH) by oxygen (O 2 ) to modulate the growth of CSH-capped cadmium sulfide (CdS) nanoparticles (NPs). This new chemical process was applied to sensitive fluorogenic and photoelectrochemical (PEC) detection of Cu 2+ ions in real samples of mineral and tap water using the photocatalytic activity of the resulting NPs. Disposable screen-printed electrodes (SPCEs) modified with electroactive polyvinylpyridine bearing osmium complex (Os-PVP) by cyclic voltammetry (CV) were employed for PEC analytical system. CdS NPs formed during the assay photocatalyze oxidation of 1-thioglycerol (TG) upon application of 0.3 V vs. Ag/AgCl to SPCEs. Os-PVP complex mediated the electron transfer between the electrode surface and CdS NPs. We proved that our assays did not suffer from interference from other ions accompanying Cu 2+ and the sensitivity of our assays covers the European Union standard limit of Cu 2+ ions in drinking water. Copyright © 2017 Elsevier B.V. All rights reserved.

One-pot synthesis of Ag-SiO2-Ag sandwich nanostructures

International Nuclear Information System (INIS)

Li Chaorong; Mei Jie; Li Shuwen; Lu Nianpeng; Wang Lina; Chen Benyong; Dong Wenjun

2010-01-01

Ag-SiO 2 -Ag sandwich nanostructures were prepared by a facile one-pot synthesis method. The Ag core, SiO 2 shell and Ag nanoparticle shell were all synthesized with polyvinylpyrrolidone, catalysed by ammonia, in the one-pot reaction. The polyvinylpyrrolidone, acting as a smart reducing agent, reduced the Ag + to Ag cores and Ag shells separately. Furthermore, the polyvinylpyrrolidone served as a protective agent to prevent the silver cores from aggregating. The SiO 2 shell and outer layer Ag nanoparticles were obtained when tetraethyl orthosilicate and ammonia were added to the silver core solution. Ammonia, acting as the catalyst, accelerated the hydrolysis of the tetraethyl orthosilicate to SiO 2 , which coated the silver cores. Furthermore, Ag(NH 3 ) 2 + ions were formed when aqueous ammonia was added to the solution, which increased the reduction capability. Then the polyvinylpyrrolidone reduced the Ag(NH 3 ) 2 + ions to small Ag nanoparticles on the surface of the Ag-SiO 2 and formed Ag-SiO 2 -Ag sandwich structures with a standard deviation of less than 4%. This structure effectively prevented the Ag nanoparticles on the silica surface from aggregating. Furthermore, the Ag-SiO 2 -Ag sandwich structures showed good catalysis properties due to the large surface area/volume value and activity of surface atoms of Ag particles.

Beam aperture and emittance growth in the AGS-Booster

International Nuclear Information System (INIS)

Parsa, Z.

1987-01-01

The authors have developed analytical tools for calculating the variation of particle action, smear and emittance growth due to nonlinear elements in accelerators (with second order perturbation theory in two dimensions). The authors' results for the AGS-Booster is presented

Flower-like Ag/AgCl microcrystals: Synthesis and photocatalytic activity

International Nuclear Information System (INIS)

Daupor, Hasan; Wongnawa, Sumpun

2015-01-01

Silver/silver chloride (Ag/AgCl) composites with a novel flower-like morphology were prepared via a hot precipitation assisted by the vinyl acetate monomer (VAM) route. An aqueous solution of AlCl 3 was mixed with the vinyl acetate monomer and acetic acid before adding a AgNO 3 solution at a temperature of 100 °C. The octapod shaped flower-like Ag/AgCl particles (or “flower-like Ag/AgCl” hereinafter) has eight petals each of which was about 7–11 μm in length. The flower-like octapods were formed by preferential overgrowth along the <111> directions of the cubic seeds. Detailed studies of the growth process at different AlCl 3 concentrations revealed that the concave cube developed into a Rubik's cube where eight corners grew further into the flower-like structures. The VAM and acetic acid concentration strongly affected the growth of the Ag/AgCl to the flower-like structure and their optimum concentrations were determined. The morphologies of these particles were carefully examined by scanning electron microscopy (SEM). The crystal structures and orientation relationship were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV–visible diffused reflectance spectroscopy (DRS). The flower-like Ag/AgCl microcrystals were tested for their photocatalytic degradation of orange G dye (OG) catalyzed by visible light. From comparative test runs, the flower-like Ag/AgCl exhibited better photocatalytic activity than simple and commercial Ag/AgCl particles. - Highlights: • Interesting transformation of microcrystals Ag/AgCl from concave cube via Rubik's cube to flower-like shape. • The first to use VAM as morphology control reagent. • High photocatalytic activity under visible light irradiation

Multi-elemental contamination and historic record in sediments from the Santos-Cubatao Estuarine System, Brazil

International Nuclear Information System (INIS)

Luiz-Silva, Wanilson; Machado, Wilson; Matos, Rosa H.R.

2008-01-01

This paper records for the first time the contamination history and identifies the sources of 38 elements in sediments from the Santos-Cubatao Estuarine System (SE Brazil), at one of the most industrialized areas in Latin America. The compositions of samples from a 260 cm long sediment core collected in the Morrao River estuary were determined by ICP-MS. Enrichment factors, principal component analysis, correlation matrixes, and the characterization of geochemical signatures permitted a consistent data evaluation. Contaminant elements such as Cr, Mn, Ni, Zn, Ga, Ag, Cd, Sn, Sb, Pb, and Bi were associated with steel plant-derived Fe concentrations, while Be, Ca, Sc, Co, Cu, Sr, Y, Zr, Nb, Hf, Ta, Th, and U were associated with fertilizer industry-derived P concentrations. An overlap of sedimentary Fe distribution and local steel plant production indicated that Fe is a reliable marker of the contamination history, allowing the estimation of sedimentation rates over a period of 45 years of industrial activities. (author)

In and Cd as defect traps in titanium dioxide

Energy Technology Data Exchange (ETDEWEB)

Schell, Juliana, E-mail: juliana.schell@cern.ch [European Organization for Nuclear Research (CERN) (Switzerland); Lupascu, Doru C. [University of Duisburg-Essen, Institute for Materials Science and Center for Nanointegration, Duisburg-Essen (CENIDE) (Germany); Martins Correia, João Guilherme [European Organization for Nuclear Research (CERN) (Switzerland); Carbonari, Artur Wilson [Universidade de São Paulo, Instituto de Pesquisas Energéticas e Nucleares (Brazil); Deicher, Manfred [Universität des Saarlandes, Experimentalphysik (Germany); Barbosa, Marcelo Baptista [Instituto de Física dos Materiais da Universidade do Porto (Portugal); Mansano, Ronaldo Domingues [Universidade de São Paulo, Escola Politécnica (Brazil); Johnston, Karl [European Organization for Nuclear Research (CERN) (Switzerland); Ribeiro, Ibere S. [Universidade de São Paulo, Instituto de Pesquisas Energéticas e Nucleares (Brazil); Collaboration: ISOLDE Collaboration, ISOLDE (European Organization for Nuclear Research (CERN) (Switzerland)

2017-11-15

We present a study of TiO{sub 2} single crystals from the point of view of the dopant atom that simultaneously behaves as the probing element. We used gamma-gamma time dependent perturbed angular correlations working with selected tracer elements ({sup 111}In/ {sup 111}Cd, {sup 111m}Cd/ {sup 111}Cd) together to investigate the different behavior of Cd and In dopants, particularly their interaction with point defects in the TiO{sub 2} lattice. Results show that the hyperfine interactions observed at {sup 111}Cd from {sup 111}In or {sup 111m}Cd decay are quite different. {sup 111}In/ {sup 111}Cd results show a single site fraction characterized by a quadrupole frequency with asymmetry parameter similar to those observed for the same probe nuclei in bulk TiO{sub 2} oxides. Results for {sup 111m}Cd/ {sup 111}Cd reveal two site fractions, one characterized by the same hyperfine parameters to those measured in bulk TiO{sub 2} and another fraction characterized by a quadrupole frequency and asymmetry parameters with higher values, as observed in thin TiO{sub 2} films and correlated with point defects. The results are discussed emphasizing the differences for Cd and In as defect traps on TiO{sub 2}.

Comparison of Vaccine-Induced Effector CD8 T Cell Responses Directed against Self- and Non-Self-Tumor Antigens

DEFF Research Database (Denmark)

Pedersen, Sara R; Sørensen, Maria R; Buus, Søren

2013-01-01

It is generally accepted that CD8 T cells play a major role in tumor control, yet vaccination aimed at eliciting potent CD8 T cell responses are rarely efficient in clinical trials. To try and understand why this is so, we have generated potent adenoviral vectors encoding the endogenous tumor Ags...... that low avidity of the self-TA-specific CD8 T cells may represent a major obstacle for efficient immunotherapy of cancer....

Thermodynamic assessments of the Ag-Gd and Ag-Nd systems

International Nuclear Information System (INIS)

Wang, S.L.; Wang, C.P.; Liu, X.J.; Ishida, K.

2009-01-01

The phase diagrams and thermodynamic properties in the Ag-Re (Re: Gd, Nd) binary systems have been assessed by using the CALPHAD (Calculation of Phase Diagrams) method on the basis of the experimental data including the thermodynamic properties and phase equilibria. The Gibbs free energies of the liquid, bcc, fcc, dhcp and hcp phases were described by the subregular solution model with the Redlich-Kister equation, and those of the intermetallic compounds (Ag 51 Gd 14 , Ag 2 Gd, AgGd, Ag 51 Nd 14 , αAg 2 Nd, βAg 2 Nd and AgNd phases) in these two binary systems were described by the sublattice model. The thermodynamic parameters of each phase in the Ag-Re (Re: Gd, Nd) binary systems were obtained, and an agreement between the calculated results and experimental data was obtained in each binary system.

Preparation of p-type NiO films by reactive sputtering and their application to CdTe solar cells

Science.gov (United States)

Ishikawa, Ryousuke; Furuya, Yasuaki; Araki, Ryouichi; Nomoto, Takahiro; Ogawa, Yohei; Hosono, Aikyo; Okamoto, Tamotsu; Tsuboi, Nozomu

2016-02-01

Transparent p-type NiO films were prepared by reactive sputtering using the facing-target system under Ar-diluted O2 gas at Tsub of 30 and 200 °C. The increasing intensity of dominant X-ray diffraction (XRD) peaks indicates improvements in the crystallinity of NiO films upon Cu doping. In spite of the crystallographic and optical changes after Cu-doping, the electrical properties of Cu-doped NiO films were slightly improved. Upon Ag-doping at 30 °C under low O2 concentration, on the other hand, the intensity of the dominant (111) XRD peaks was suppressed and p-type conductivity increased from ˜10-3 to ˜10-1 S cm-1. Finally, our Ag-doped NiO films were applied as the back contact of CdTe solar cells. CdTe solar cells with a glass/ITO/CdS/CdTe/NiO structure exhibited an efficiency of 6.4%, suggesting the high potential of using p-type NiO for the back-contact film in thin-film solar cells.

Adsorption of trace elements of radionuclides on hydrous iron oxides

International Nuclear Information System (INIS)

Music, S.; Ristic, M.

1988-01-01

Factors that influence the adsorption of trace elements or radionuclides on hydrous iron oxides were investigated. The adsorption of monovalent cations (Cs + , Rb + ) on hydrous iron oxides is not strongly pH-dependent and it can be regarded as nonspecific. On the other hand, the adsorption of Ag + , divalent cations (Zn 2+ , Cd 2+ , Mn 2+ , Sr 2+ ) or trivalent cations (Cr 3+ , La 3+ , Ce 3+ , Eu 3+ , Gd 3+ , Er 3+ , Yb 3+ ) is strongly pH-dependent. The regularities of the adsorption of these cations on hydrous iron oxides are discussed. The differences in the adsorption behaviour of some divalent and trivalent cations are also explained. Freshly precipitated iron(III) hydroxide can be used for the decontamination of radionuclides from low-level waste solutions. However, the efficacy of decontamination depends on the oxidation state and the chemical properties of radionuclides. (author) 40 refs.; 9 figs

Impact of HBeAg on the maturation and function of dendritic cells.

Science.gov (United States)

Lan, Songsong; Wu, Lecan; Wang, Xiuyan; Wu, Jinming; Lin, Xianfan; Wu, Wenzhi; Huang, Zhiming

2016-05-01

HBV infection typically leads to chronic hepatitis in newborns and some adults with weakened immune systems. The mechanisms by which virus escapes immunity remain undefined. Regulatory dendritic cells (DCregs) contributing to immune escape have been described. We wondered whether or not HBeAg as an immunomodulatory protein could induce DCreg which might subsequently result into HBV persistence. The immunophenotyping, T-cell activation and cytokine production were analyzed in HBeAg-treated DCs from normal or cyclophosphamide (Cy)-induced immunocompromised mice. HBeAg tended to promote bone marrow derived DCs (BMDCs) from Cy-treated mice into CD11b(high)PIR-B(+) regulatory DCs exhibiting the lowest T-cell stimulatory capacity and interleukin (IL)-12p70 production compared with controls. Neutralization of IL-10 significantly inhibited the regulatory effect of these DCs on T-cell stimulation of mature DCs. After lipopolysaccharides (LPS) stimulation, marked phosphorylation of Akt was detected in HBeAg treated DCs from immunocompromised mice. Blocking the PI3K-Akt pathway by LY294002 led to an enhancement of IL-12 production. PI3K signalling pathway appears to be involved in the decreased IL-12 secretion by HBeAg treated DCs. These findings suggest that HBeAg may program the generation of a new DC subset with regulatory capacity under the condition of immunosuppression, which may presumably contribute to the persistent HBV infection. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Ag loading induced visible light photocatalytic activity for pervoskite SrTiO3 nanofibers

Science.gov (United States)

Wu, Yeqiu; He, Tao

2018-06-01

The synthesis and photocatalytic activities of Ag-SrTiO3 nanofibers were reported in this work. The fabricated Ag-SrTiO3 nanofibers were characterized by TG-DSC, XRD, IR, XPS, SEM, TEM, DRS and ESR techniques. The XRD and IR results show that Ag-SrTiO3 nanofibers have a perovskite structure after the heat treatment at 700 °C. The XPS result shows that Ag element exists as Ag0 in the fabricated Ag-SrTiO3 nanofibers. The SEM and TEM images indicate the obtaining of nanofibers with porous structure. The photocatalytic activity of Ag-SrTiO3 nanofibers was evaluated by degrading RhB and MB under visible light irradiation. The Ag-SrTiO3 nanofibers show excellent photocatalytic activity under visible light irradiation because of the surface plasmon resonance effect of Ag0. In the photocatalysis process of RhB and MB, lots of hydroxyl radicals were generated, which plays the key role in the decomposition of organic pollutants.

Study of impurity-defect interaction by perturbed angular correlations: 111Cd in silver

International Nuclear Information System (INIS)

Sage, Francoise.

1975-01-01

The quadrupole interaction of 111 Cd nuclei following the decay of 111 In implanted by the 109 Ag(α,2n) 111 In reaction into a cubic Ag lattice was measured using the time-differential perturbed-angular correlation technique. A non vanishing quadrupole interaction corresponding to a distribution of electric field gradients was observed, due to the interaction between the 111 Cd impurity and the defects created during the recoil of 111 In nuclei. For low temperature (77 K) irradiations, it has been shown that i) the angular correlation pattern depends on the intensity of α beam current, due to the interaction between defect cascades at high α beam intensity; and ii) it also depends on the annealing of the irradiated sample at different temperatures; the change in the defect configuration around the impurities is then due to the mobility of the various defects [fr

Settling properties of aerobic granular sludge (AGS) and aerobic granular sludge molasses (AGSM)

Science.gov (United States)

Mat Saad, Azlina; Aini Dahalan, Farrah; Ibrahim, Naimah; Yasina Yusuf, Sara; Aqlima Ahmad, Siti; Khalil, Khalilah Abdul

2018-03-01

Aerobic granulation technology is applied to treat domestic and industrial wastewater. The Aerobic granular sludge (AGS) cultivated has strong properties that appears to be denser and compact in physiological structure compared to the conventional activated sludge. It offers rapid settling for solid:liquid separation in wastewater treatment. Aerobic granules were developed using sequencing batch reactor (SBR) with intermittent aerobic - anaerobic mode with 8 cycles in 24 hr. This study examined the settling velocity performance of cultivated aerobic granular sludge (AGS) and aerobic granular sludge molasses (AGSM). The elemental composition in both AGS and AGSM were determined using X-ray fluorescence (XRF). The results showed that AGSM has higher settling velocity 30.5 m/h compared to AGS.

Tribological behavior and self-healing functionality of TiNbCN-Ag coatings in wide temperature range

Science.gov (United States)

Bondarev, A. V.; Kiryukhantsev-Korneev, Ph. V.; Levashov, E. A.; Shtansky, D. V.

2017-02-01

Ag- and Nb-doped TiCN coatings with about 2 at.% of Nb and Ag contents varied between 4.0 and 15.1 at.% were designed as promising materials for tribological applications in a wide temperature range. We report on the structure, mechanical, and tribological properties of TiNbCN-Ag coatings fabricated by simultaneous co-sputtering of TiC0.5 + 10%Nb2C and Ag targets in comparison with those of Ag-free coating. The tribological characteristics were evaluated during constant-temperature tests both at room temperature and 300 °C, as well as during dynamic temperature ramp tests in the range of 25-700 °C. The coating structure and elemental composition were studied by means of X-ray diffraction, scanning and transmission electron microscopy, and glow discharge optical emission spectroscopy. The coating microstructures and elemental compositions inside wear tracks, as well as the wear products, were examined by scanning electron microscopy, energy-dispersive spectroscopy, and Raman spectroscopy. We demonstrate that simultaneous alloying with Nb and Ag permits to overcome the main drawbacks of TiCN coatings such as their relatively high values of friction coefficient at elevated temperatures and low oxidation resistance. It is shown that a relatively high amount of Ag (15 at.%) is required to provide enhanced tribological behavior in a wide temperature range of 25-700 °C. In addition, the prepared Ag-doped coatings demonstrated active oxidation protection and self-healing functionality due to the segregation of Ag metallic particles in damage areas such as cracks, pin-holes, or oxidation sites.

In situ solid-state fabrication of hybrid AgCl/AgI/AgIO3 with improved UV-to-visible photocatalytic performance.

Science.gov (United States)

Xie, Jing; Cao, Yali; Jia, Dianzeng; Li, Yizhao; Wang, Kun; Xu, Hui

2017-09-28

The AgCl/AgI/AgIO 3 composites were synthesized through a one-pot room-temperature in situ solid-state approach with the feature of convenient and eco-friendly. The as-prepared composites exhibit superior photocatalytic performance than pure AgIO 3 for the degradation of methyl orange (MO) under both UV and visible light irradiation. The photodegradation rate toward MO of the AgCl/AgI/AgIO 3 photocatalyst can reach 100% after 12 min irradiation under UV light, or 85.4% after 50 min irradiation under visible light, being significantly higher than AgCl, AgI, AgIO 3 and AgI/AgIO 3 . In addition, the AgCl/AgI/AgIO 3 photocatalyst possesses strong photooxidation ability for the degradation of rhodamine B (RhB), methylene blue (MB), phenol, bisphenol A (BPA) and tetracycline hydrochloride under visible light irradiation. The reactive species capture experiments confirmed that the h + and •O 2- play an essential role during the photocatalytic process under UV light or visible light irradiation. The enhanced effect may be beneficial from the enhanced light adsorption in full spectrum and increased separation efficiency of photogenerated hole-electron pairs, which can be ascribed to the synergistic effect among AgCl, AgI and AgIO 3 nanoplates in AgCl/AgI/AgIO 3 composites.