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Sample records for ag cadmium cd

  1. Cadmium telluride (CdTe) and cadmium selenide (CdSe) leaching behavior and surface chemistry in response to pH and O2.

    PubMed

    Zeng, Chao; Ramos-Ruiz, Adriana; Field, Jim A; Sierra-Alvarez, Reyes

    2015-05-01

    Cadmium telluride (CdTe) and cadmium selenide (CdSe) are increasingly being applied in photovoltaic solar cells and electronic components. A major concern is the public health and ecological risks associated with the potential release of toxic cadmium, tellurium, and/or selenium species. In this study, different tests were applied to investigate the leaching behavior of CdTe and CdSe in solutions simulating landfill leachate. CdTe showed a comparatively high leaching potential. In the Toxicity Characteristic Leaching Procedure (TCLP) and Waste Extraction Test (WET), the concentrations of cadmium released from CdTe were about 1500 and 260 times higher than the regulatory limit (1 mg/L). In contrast, CdSe was relatively stable and dissolved selenium in both leaching tests was below the regulatory limit (1 mg/L). Nonetheless, the regulatory limit for cadmium was exceeded by 5- to 6- fold in both tests. Experiments performed under different pH and redox conditions confirmed a marked enhancement in CdTe and CdSe dissolution both at acidic pH and under aerobic conditions. These findings are in agreement with thermodynamic predictions. Taken as a whole, the results indicate that recycling of decommissioned CdTe-containing devices is desirable to prevent the potential environmental release of toxic cadmium and tellurium in municipal landfills.

  2. High Visible Photoelectrochemical Activity of Ag Nanoparticle-Sandwiched CdS/Ag/ZnO Nanorods.

    PubMed

    Yang, Xu; Li, Hui; Zhang, Wu; Sun, Mingxuan; Li, Lequn; Xu, Ning; Wu, Jiada; Sun, Jian

    2017-01-11

    We report on the sensitizing of CdS-coated ZnO (CdS/ZnO) nanorods (NRs) by Ag nanoparticles (NPs) embedded between the CdS coating and the ZnO nanorod and the improved optical and photoelectrochemical properties of the Ag NP-sandwiched nanostructure CdS/Ag/ZnO NRs. The CdS/Ag/ZnO NRs were fabricated by growing Ag NPs on hydrothermally grown ZnO NRs and subsequently depositing CdS coatings followed by subsequent N2 annealing. The structure of the fabricated CdS/Ag/ZnO NRs was characterized by field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Raman backscattering, revealing that the ZnO NRs and the CdS coatings are both structured with hexagonal wurtzite and the Ag NPs contact well with ZnO and CdS. Optical properties were evaluated by measuring optical absorption and photoluminescence, showing that the Ag NPs behave well as sensitizers for optical property improvement and the CdS/Ag/ZnO NRs exhibit better photoresponse in a wide spectral region than CdS/ZnO because of plasmon-enhanced absorption due to the embedment of Ag NPs. The Ag NPs also serve as electron relays from CdS to ZnO, facilitating electron transfer from the CdS coatings to the ZnO NRs. The excellent photoresponse and efficient electron transfer make the CdS/Ag/ZnO NRs highly photoelectrochemically active. The CdS/Ag/ZnO NRs fabricated on indium-tin oxide present much better photoelectrochemical performance as photoanodes working in the visible region than CdS/ZnO NRs without Ag NPs. Under visible illumination, a maximum optical-to-chemical conversion efficiency of 3.13% is obtained for CdS/Ag/ZnO NR photoanodes against 1.35% for CdS/ZnO NR photoanodes.

  3. Selective turn-on fluorescence sensor for Ag+ using cysteamine capped CdS quantum dots: determination of free Ag+ in silver nanoparticles solution.

    PubMed

    Khantaw, Thitima; Boonmee, Chanida; Tuntulani, Thawatchai; Ngeontae, Wittaya

    2013-10-15

    Cadmium sulfide quantum dots capped with cysteamine (Cys-CdS QDs) were demonstrated as a selective fluorescence probe for sensing of free trace silver ions. The fluorescence intensity of the Cys-CdS QDs can be enhanced only in the presence of free Ag(+) and the fluorescence spectrum was slightly red shift from the original spectra. In addition, the fluorescence intensities were linearly increased upon increasing Ag(+) concentration. At the optimized condition for Ag(+) detection, when adding other metal ions to the Cys-CdS QDs solution, fluorescence spectra of Cys-CdS QDs did not change significantly revealing good selectivity of the sensors towards Ag(+). The working linear concentration range was found to be 0.1-1.5 µM with LOD of 68 nM. The proposed sensor was then applied to detect free Ag(+) in the silver nanoparticles solution. The results showed that the proposed sensor can be efficiently used with good accuracy and precision providing the simple method for detection of free Ag(+) in silver nanoparticles of quality control products.

  4. Experimental and theoretical spectroscopic studies of Ag-, Cd- and Pb-sodalite

    NASA Astrophysics Data System (ADS)

    Mikuła, A.; Król, M.; Koleżyński, A.

    2016-12-01

    Synthetic sodalite structures containing silver, cadmium and lead cations have been obtained and structurally identified. In order to examine the changes in sodalite spectra envelope resulting from the substitution of initial sodium cations by Ag+, Cd2+ and Pb2+, a series of theoretical sodalite model structures with various Me/Na ratio and different anions have been prepared. Based on ab initio calculations and experimental results, it has been determined how the type and amount of both extra framework cations and anions affect the vibrational spectra and structural properties of sodalite. Additionally, an attempt to identified of bands associated with the individual cations and anions vibration has been undertaken.

  5. Accumulation and localization of cadmium in potato (Solanum tuberosum) under different soil Cd levels.

    PubMed

    Chen, Zhifan; Zhao, Ye; Gu, Lei; Wang, Shuifeng; Li, Yongliang; Dong, Fangli

    2014-06-01

    Phytoavailability and uptake mechanism of Cd in edible plant tissues grown on metal polluted agricultural soils has become a growing concern worldwide. Uptake, transport, accumulation and localization of cadmium in potato organs under different soil Cd levels were investigated using inductively-coupled plasma mass spectrometry and energy dispersive X-ray microanalysis. Results indicated that Cd contents in potato organs increased with increasing soil Cd concentrations, and the order of Cd contents in different organs was leaves > stems/roots > tubers. Root-to-stem Cd translocation coefficients ranged from 0.89 to 1.81. Cd localization in potato tissues suggested that leaves and stems should be the main compartment of Cd storage and uptake. Although low concentrations of Cd migrated from the root to tuber, Cd accumulation in the tuber exceeded the standard for food security. Therefore, the planting of potato plants in farmland containing Cd should be closely evaluated due to its potential to present health risks.

  6. Cadmium Stabilization Efficiency and Leachability by CdAl4O7 Monoclinic Structure.

    PubMed

    Su, Minhua; Liao, Changzhong; Chuang, Kui-Hao; Wey, Ming-Yen; Shih, Kaimin

    2015-12-15

    This study investigated the stabilization efficiencies of using an aluminum-rich precursor to incorporate simulated cadmium-bearing waste sludge and evaluated the leaching performance of the product phase. Cadmium oxide and γ-alumina mixtures with various Cd/Al molar ratios were fired at 800-1000 °C for 3 h. Cadmium could be crystallochemically incorporated by γ-alumina into CdAl4O7 monoclinic phase and the reaction was strongly controlled by the treatment temperature. The crystal structure details of CdAl4O7 were solved and refined with the Rietveld refinement method. According to the structural refinement results, the stabilization efficiencies were quantified and expressed as a transformation ratio (TR) with optimized processing parameters. The preferred treatment temperature was found to be 950 °C for mixtures with a Cd/Al molar ratio of 1/4, as its TR value indicated the cadmium incorporation was nearly completed after a 3 h treatment scheme. Constant-pH leaching tests (CPLT) were conducted by comparing the leachability of the CdO and CdAl4O7 phases in a pH 4.0 environment. A remarkable reduction in cadmium leachability could be achieved via monoclinic CdAl4O7 structure formation to effectively stabilize hazardous cadmium in the waste stream. The CPLT and X-ray photoelectron spectroscopy (XPS) results suggested incongruent dissolution behavior during the leaching of the CdAl4O7 phase.

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

    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 37 nm, respectively for pure and Ag doped samples. FT-IR study confirmed the presence of CdO and Ag at 677 and 459 cm-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.

  8. Size distribution effects of cadmium tellurium quantum dots (CdS/CdTe) immunotoxicity on aquatic organisms.

    PubMed

    Bruneau, A; Fortier, M; Gagne, F; Gagnon, C; Turcotte, P; Tayabali, A; Davis, T L; Auffret, M; Fournier, M

    2013-03-01

    The increasing use of products derived from nanotechnology has raised concern about their potential toxicity to aquatic life. This study sought to examine the comparative immunotoxicity of capped cadmium sulphide/cadmium telluride (CdS/CdTe) quantum dots (QDs) and possible impact of particle/aggregate size on two bivalves (Mytilus edulis and Elliptio complanata) and a fish (Oncorhynchus mykiss). The QDs were dispersed in sterile water and fractionated using a series of micro/ultrafiltration membranes of decreasing pore size: 450 nm, 100 nm, 50 nm, 25 nm, 100 kDa (6.8 nm), 30 kDa (4.6 nm), 10 kDa (3.2 nm) and 1 kDa (1.5 nm). The total concentrations of cadmium and tellurium were determined for the filtered material and for that retained on the filters (retentate). The immunotoxicity was determined by measuring cell viability and phagocytosis. Results revealed that nanoparticles retained on the ultrafilters had a higher Cd/Te ratio compared to the permeate fraction (ratio of 5 and 2 respectively) which could indicate that the CdS core was not associated with the permeable fraction of Cd. Our results demonstrate that the toxicity of CdS/CdTe QDs was concentration and size dependent. Large CdS/CdTe QD aggregates (25 nm < size < 100 nm) reduced phagocytosis more than did smaller nanoparticles (<25 nm). Moreover, our results revealed that the different species responded differently to these fractions. Mytilus edulis hemocytes were less sensitive to CdS/CdTe QDs than the Oncorhynchus mykiss macrophage and Elliptio complanata hemocytes.

  9. Cadmium triggers Elodea canadensis to change the surrounding water pH and thereby Cd uptake.

    PubMed

    Javed, M Tariq; Greger, Maria

    2011-01-01

    This study was aimed to investigate the influence of Elodea canadensis shoots on surrounding water pH in the presence of cadmium and the effect of plant-induced pH on cadmium uptake. The pH change in the surrounding nutrient solution and Cd uptake by Elodea shoots were investigated after cultivation of various plant densities (1, 3, 6 plants per 500 ml) in hydroponics at a starting pH of 4.0 and in the presence of different concentrations of cadmium (0, 0.1, 0.5 microM). Cadmium uptake was also investigated at different constant pH (4.0, 4.5, 5.5 and 6.5). To investigate if the pH change arose from photosynthetic activities, plants were grown under light, darkness or in the presence of a photosynthetic inhibitor, 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), and 0.5 microM cadmium in the solution. Elodea had an ability to increase the surrounding water pH, when the initial pH was low, which resulted in increased accumulation of Cd. The higher the plant density, the more pronounced was the pH change. The pH increase was not due to the photosynthetic activity since the pH rise was more pronounced under darkness and in the presence of DCMU. The pH increase by Elodea was triggered by cadmium.

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

    NASA Astrophysics Data System (ADS)

    Boye, M.; Wake, B. D.; Lopez Garcia, P.; Bown, J.; Baker, A. R.; Achterberg, E. P.

    2012-08-01

    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-nutrient-low-chlorophyll waters

  11. Electrochemically Deposited Cadmium Electrode for Sealed Ni-cd Cells

    NASA Technical Reports Server (NTRS)

    Houston, W. H.; Edgar, T. A.

    1984-01-01

    An investigation into the work on electrochemical cadmium deposition processes is describred. A beaker impregnation system is constructed to investigate the practical limits of loading and the effect of various process parameters. Reasonably high loadings of cadmium are obtained and the process appears amenable to tight control and the production of uniform consistent electrodes. A pilot impregnation facility is built to further investigate electrodeposition processes. Both the inert anode and consummable anode processes are investigated. Results of this evaluation and an analysis of associated problems are presented.

  12. Structural and chemical properties of highly oriented cadmium sulfide (CdS) cauliflower films

    NASA Astrophysics Data System (ADS)

    Vemuri, R. S.; Gullapalli, S. K.; Zubia, D.; McClure, J. C.; Ramana, C. V.

    2010-08-01

    Cadmium sulfide (CdS) films have been produced by sputter-deposition varying the sputtering-power ( P) in the range of 60-120 W. The crystal structure, morphology and chemical quality of the CdS films has been investigated employing X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and X-ray spectrometry (EDS). Structural characterization indicates that all the CdS layers exhibit cauliflower morphology. Highly oriented, single phase hexagonal-CdS films can be produced at P = 75-105 W while the films at other power contain mixed phases. Characterization using XPS and EDS indicate that the CdS layers are nearly stoichiometric at P = 75-105 W, at which point S-deficiency is induced resulting in Cd-rich-CdS layers.

  13. A dry method to synthesize dendritic Ag2Se nanostructures utilizing CdSe quantum dots and Ag thin films

    NASA Astrophysics Data System (ADS)

    Hu, Lian; Zhang, Bingpo; Xu, Tianning; Li, Ruifeng; Wu, Huizhen

    2015-01-01

    Dendritic Ag2Se nanostructures are synthesized in a dry environment by UV irradiating the hybrids composed of CdSe quantum dots (QDs) and silver (Ag). UV irradiation on CdSe QDs induces a photooxidation effect on the QD surface and leads to the formation of SeO2 components. Then SeO2 reacts with the Ag atoms in either Ag film or QD layer to produce the Ag2Se. The growth mechanism of Ag2Se dendrites on solid Ag films is explored and explained by a diffusion limited aggregation model in which the QD layer provides enough freedom for Ag2Se motion. Since the oxidation of the CdSe QDs is the critical step for the Ag2Se dendrites formation this dry chemical interaction between QDs and Ag film can be applied in the study of the QD surface chemical properties. With this dry synthesis method, the Ag2Se dendrites can also be facilely formed at the designed area on Ag substrates.

  14. A dry method to synthesize dendritic Ag2Se nanostructures utilizing CdSe quantum dots and Ag thin films.

    PubMed

    Hu, Lian; Zhang, Bingpo; Xu, Tianning; Li, Ruifeng; Wu, Huizhen

    2015-01-09

    Dendritic Ag2Se nanostructures are synthesized in a dry environment by UV irradiating the hybrids composed of CdSe quantum dots (QDs) and silver (Ag). UV irradiation on CdSe QDs induces a photooxidation effect on the QD surface and leads to the formation of SeO2 components. Then SeO2 reacts with the Ag atoms in either Ag film or QD layer to produce the Ag2Se. The growth mechanism of Ag2Se dendrites on solid Ag films is explored and explained by a diffusion limited aggregation model in which the QD layer provides enough freedom for Ag2Se motion. Since the oxidation of the CdSe QDs is the critical step for the Ag2Se dendrites formation this dry chemical interaction between QDs and Ag film can be applied in the study of the QD surface chemical properties. With this dry synthesis method, the Ag2Se dendrites can also be facilely formed at the designed area on Ag substrates.

  15. Evolution of oxygenated cadmium sulfide (CdS:O) during high-temperature CdTe solar cell fabrication

    SciTech Connect

    Meysing, Daniel M.; Reese, Matthew O.; Warren, Charles W.; Abbas, Ali; Burst, James M.; Mahabaduge, Hasitha P.; Metzger, Wyatt K.; Walls, John M.; Lonergan, Mark C.; Barnes, Teresa M.; Wolden, Colin A.

    2016-12-01

    Oxygenated cadmium sulfide (CdS:O) produced by reactive sputtering has emerged as a promising alternative to conventional CdS for use as the n-type window layer in CdTe solar cells. Here, complementary techniques are used to expose the window layer (CdS or CdS:O) in completed superstrate devices and combined with a suite of materials characterization to elucidate its evolution during high temperature device processing. During device fabrication amorphous CdS:O undergoes significant interdiffusion with CdTe and recrystallization, forming CdS1-yTey nanocrystals whose Te fraction approaches solubility limits. Significant oxygen remains after processing, concentrated in sulfate clusters dispersed among the CdS1-yTey alloy phase, accounting for ~30% of the post-processed window layer based on cross-sectional microscopy. Interdiffusion and recrystallization are observed in devices with un-oxygenated CdS, but to a much lesser extent. Etching experiments suggest that the CdS thickness is minimally changed during processing, but the CdS:O window layer is reduced from 100 nm to 60-80 nm, which is confirmed by microscopy. Alloying reduces the band gap of the CdS:O window layer to 2.15 eV, but reductions in thickness and areal density improve its transmission spectrum, which is well matched to device quantum efficiency. The changes to the window layer in the reactive environments of device fabrication are profoundly different than what occurs by thermal annealing in an inert environment, which produced films with a band gap of 2.4 eV for both CdS and CdS:O. These results illustrate for the first time the significant changes that occur to the window layer during processing that are critical to the performance of CdTe solar cells.

  16. Uptake and excretion of cadmium, cdEDTA, and zinc by Macoma balthica

    SciTech Connect

    McLeese, D.W.; Ray, S.

    1984-01-01

    The accumulation of cadmium from sea water by marine invertebrates has been studied. Chelation of Cd with ethylenediaminetetraacetic acid (EDTA) was reported to double the rate of Cd uptake and the final tissue concentration in mussels. The physicochemical properties of Cd and Zn are similar and it has been suggested that the two elements are biologically antagonistic. When both Cd and Zn are present, the level of Cd is reduced in polychaete worms and bivalve molluscs. In contrast, the level of Cd remained fairly constant for most tissues of P. montagui exposed to Cd at a constant level and to Zn at different levels. Because of the contrasting results concerning the effects of Cd and Zn combined, and of chelated Cd, this study was undertaken to determine if exposure to Cd and Zn in combination affects uptake and excretion of either element by the deposit-feeding mollusc, Macoma balthica. In addition, the effects of Cd complexed with EDTA and the chemical form of Cd on uptake of Cd in M. Balthica were examined.

  17. Kinetics of sulfuric acid leaching of cadmium from Cd-Ni zinc plant residues.

    PubMed

    Safarzadeh, Mohammad Sadegh; Moradkhani, Davood; Ojaghi-Ilkhchi, Mehdi

    2009-04-30

    Cd-Ni filtercakes are produced continuously at the third purification step in the electrolytic production of zinc in the National Iranian Lead and Zinc Company (NILZ) in northwestern Iran. In this research, the dissolution kinetics of cadmium from Cd-Ni residues produced in NILZ plant has been investigated. Hence, the effects of temperature, sulfuric acid concentration, particle size and stirring speed on the kinetics of cadmium dissolution in sulfuric acid were studied. The dissolution kinetics at 25-55 degrees C and tcadmium and sulfate ions through the porous region of alloying layer (Cd(5)Ni, Cd(2)Ni(1.9) and Cd(10)Cu(3)) as the rate determining step. This finding is in accordance with the apparent activation energy (E(a)) of 13.363 kJ/mol and a linear relationship between the rate constant and the reciprocal of squared particle size. Arrhenius constant was calculated as 6.3942 min(-1). The order of reaction with respect to sulfuric acid concentration, solid/liquid ratio and particle size were also achieved. The rate of reaction at first 5 min based on diffusion-controlled process can be expressed by a semi-empirical equation as:It was determined that the dissolution rate increased with increasing sulfuric acid concentration and decreasing particle size.

  18. Converting Ag₂S-CdS and Ag₂S-ZnS into Ag-CdS and Ag-ZnS nanoheterostructures by selective extraction of sulfur.

    PubMed

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

    2014-11-01

    A mild three-step solution strategy is developed to prepare Ag-MS (M=Zn, Cd) nanoheterostructures composed of MS nanorods with silver tips. First, Ag2S-MS heterostructures are synthesized by following a solution-liquid-solid mechanism with Ag2S nanoparticles as catalysts, then the Ag2S sections of the heterostructures are converted into silver nanoparticles by selective extraction of sulfur. Notably, for the prepared Ag-CdS heterostructures, the localized surface plasmon resonance of silver remarkably intensifies the photoluminescence of CdS by enhancing the excitation light absorption, which is beneficial for potential applications of CdS nanoparticles in the fields of biolabeling, light-emitting diodes, and so forth. The strategy reported herein would be useful for designing and fabricating other metal-semiconductor hybrid nanostructures with desirable performances.

  19. Frequency dependent electrical properties of nano-CdS/Ag junctions

    NASA Astrophysics Data System (ADS)

    Mohanta, D.; Choudhury, A.

    2005-05-01

    Polymer embedded cadmium sulfide nanoparticles/quantum dots were synthesized by a chemical route using polyvinyl alcohol (lmw) as the desired matrix. In an attempt to measure the electrical properties of nano-CdS/Ag samples, we propose that contribution from surface traps are mainly responsible in determining the I˜ V and C˜ V characteristics in high frequency ranges. To be specific, beyond 1.2 MHz, the carrier injection from the trap centers of the embedded quantum dots is ensured by large current establishment even at negative biasing condition of the junction. The unexpected nonlinear signature of C˜ V response is believed to be due to the fact that while trying to follow very high signal frequency (at least 10-3 of recombination frequency), there is complete abruptness in carrier trapping (charging) or/and detrapping (decay) in a given CdS nanoparticle assembly. The frequency dependent unique role of the trap carriers certainly find application in nanoelectronic devices at a desirable frequency of operation.

  20. Ag nanoparticle mediated growth of CdS nanobelts

    NASA Astrophysics Data System (ADS)

    Sreejith, K.; Nuwad, J.; Thinaharan, C.; Dey, G. K.; Pillai, C. G. S.

    2007-06-01

    Catalytic growth of CdS have been carried out on large scale by evaporation of bulk CdS on Ag deposited Si (1 1 1) at atmospheric pressure. The as prepared CdS had wurtzite structure as evidenced by X-ray diffraction. The nanostructures were beltlike with several tens of micrometers length, several micrometers width and few nanometers to tens of nanometers thick as seen by scanning electron microscope and confirmed by TEM studies. The nanobelts were single crystalline in nature and showed reflection corresponding to (1 1 2) and (0 0 2) planes in SAED. The PL studies revealed the green band due to band gap emission and red band due to emission from the surface states. The higher intensity of the defect emission indicated the presence of considerable concentration of surface defects in the as prepared sample. The deposition of CdS could be explained on the basis of catalyst assisted vapor-liquid-solid and vapor-solid mechanism.

  1. Cd-Resistant Strains of B. cereus S5 with Endurance Capacity and Their Capacities for Cadmium Removal from Cadmium-Polluted Water.

    PubMed

    Wu, Huiqing; Wu, Qingping; Wu, Guojie; Gu, Qihui; Wei, Linting

    2016-01-01

    The goal of this study was to identify Cd-resistant bacterial strains with endurance capacity and to evaluate their ability to remove cadmium ions from cadmium-polluted water. The Bacillus cereusS5 strain identified in this study had the closest genetic relationship with B. cereus sp. Cp1 and performed well in the removal of Cd2+ions from solution. The results showed that both the live and dead biomasses of the Cd2+-tolerant B. cereus S5 strain could absorb Cd2+ ions in solution but that the live biomass of the B. cereus S5 strain outperformed the dead biomass at lower Cd2+concentrations. An analysis of the cadmium tolerance genes of B. cereus S5 identified ATPase genes that were associated with cadmium tolerance and involved in the ATP pumping mechanism. The FTIR spectra revealed the presence of amino, carboxyl and hydroxyl groups on the pristine biomass and indicated that the cadmium ion removal ability was related to the structure of the strain. The maximum absorption capacity of the B. cereus S5 strain in viable spore biomass was 70.16 mg/g (dry weight) based on a pseudo-second-order kinetic model fit to the experimental data. The Langmuir and Langmuir-Freundlich isotherm adsorption models fit the cadmium ion adsorption data well, and the kinetic curves indicated that the adsorption rate was second-order. For Cd2+ concentrations (mg/L) of 1-109 mg/L, good removal efficiency (>80%) was achieved using approximately 3.48-10.3 g/L of active spore biomass of the B. cereus S5 strain. A cadmium-tolerant bacteria-activated carbon-immobilized column could be used for a longer duration and exhibited greater treatment efficacy than the control column in the treatment of cadmium-polluted water. In addition, a toxicity assessment using mice demonstrated that the biomass of the B. cereus S5 strain and its fermentation products were non-toxic. Thus, the isolated B. cereus S5 strain can be considered an alternative biological adsorbent for use in emergency responses to severe

  2. Cd-Resistant Strains of B. cereus S5 with Endurance Capacity and Their Capacities for Cadmium Removal from Cadmium-Polluted Water

    PubMed Central

    Wu, Huiqing; Wu, Qingping; Wu, Guojie; Gu, Qihui; Wei, Linting

    2016-01-01

    The goal of this study was to identify Cd-resistant bacterial strains with endurance capacity and to evaluate their ability to remove cadmium ions from cadmium-polluted water. The Bacillus cereusS5 strain identified in this study had the closest genetic relationship with B. cereus sp. Cp1 and performed well in the removal of Cd2+ions from solution. The results showed that both the live and dead biomasses of the Cd2+-tolerant B. cereus S5 strain could absorb Cd2+ ions in solution but that the live biomass of the B. cereus S5 strain outperformed the dead biomass at lower Cd2+concentrations. An analysis of the cadmium tolerance genes of B. cereus S5 identified ATPase genes that were associated with cadmium tolerance and involved in the ATP pumping mechanism. The FTIR spectra revealed the presence of amino, carboxyl and hydroxyl groups on the pristine biomass and indicated that the cadmium ion removal ability was related to the structure of the strain. The maximum absorption capacity of the B. cereus S5 strain in viable spore biomass was 70.16 mg/g (dry weight) based on a pseudo-second-order kinetic model fit to the experimental data. The Langmuir and Langmuir-Freundlich isotherm adsorption models fit the cadmium ion adsorption data well, and the kinetic curves indicated that the adsorption rate was second-order. For Cd2+ concentrations (mg/L) of 1–109 mg/L, good removal efficiency (>80%) was achieved using approximately 3.48–10.3 g/L of active spore biomass of the B. cereus S5 strain. A cadmium-tolerant bacteria-activated carbon-immobilized column could be used for a longer duration and exhibited greater treatment efficacy than the control column in the treatment of cadmium-polluted water. In addition, a toxicity assessment using mice demonstrated that the biomass of the B. cereus S5 strain and its fermentation products were non-toxic. Thus, the isolated B. cereus S5 strain can be considered an alternative biological adsorbent for use in emergency responses to

  3. Fish bioturbation of cadmium-contaminated sediments: Factors affecting Cd availability to Daphnia magna

    SciTech Connect

    Wall, S.B.; La Point, T.W.; Isely, J.J.

    1996-03-01

    Benthic fish bioturbation of contaminated sediments is thought to enhance exposure and, potentially, bioaccumulation into planktonic organisms. Exposures were conducted with cadmium-spiked sediment, 1.0 mg/kg nominal concentrations, and koi carp (Cyprinus carpio). Daphnia magna were placed in aquaria with and without fish for 6 d and Cd bioaccumulation was measured every 48 h. Koi carp bioturbation increased mean total suspended solids (TSS) in two trials from 0.001 mg/L to 44.4 mg/L and 19.2 mg/L to 762.4 mg/L. Mean aqueous Cd concentrations increased from1.4 {micro}g/L to 2.8 {micro}g/L, and from 1.6 {micro}g/L to 13.2 {micro}g/L. Cadmium binding capacity increased from 28.9 {micro}g/L to 169.8 {micro}g/L in with-fish treatments when compared to controls. However, Daphnia magna body burdens did not increase. Mean Cd residues of daphnids exposed with fish, 9.2 {micro}g/g, were not statistically different from without-fish exposures, 8.0 {micro}g/g. Body burdens slightly decreased in the first trial after the with-fish treatment, 9.4 {micro}g/g to 8.3 {micro}g/g. Fish size was partially correlated with TSS and aqueous Cd concentrations and TSS positively correlated with binding capacity. Because increased TSS in the with-fish treatment resulted in increased binding capacity, it is probable that cadmium bioavailability decreased. Although koi carp were capable of remobilizing Cd from sediment, Cd bioaccumulation into Daphnia magna was not significant.

  4. Optical absorption, induced bleaching, and photoluminescence of CdSe nanoplatelets grown in cadmium octanoate matrix.

    PubMed

    Lyashchova, Alina; Dmytruk, Andriy; Dmitruk, Igor; Klimusheva, Gertruda; Mirnaya, Tetyana; Asaula, Vitaliy

    2014-02-20

    CdSe nanoparticles (NPs) are chemically synthesized in thermotropic ionic liquid crystalline (LC) phase of cadmium octanoate that was used as a nanoreactor. The nanocomposite samples are obtained by the rapid cooling of the LC phase to room temperature. Observed doublet structure in absorption spectra of the nanocomposites is characteristic for the two-dimensional CdSe nanoplatelets (NPLs). The thicknesses of the CdSe NPLs are 1.6, 1.9 and 2.3 nm as determined from the absorption spectra, and correspond to 4, 5 and 6 CdSe monolayers, respectively. Induced simultaneous bleaching of the doublet components observed under femtosecond laser excitation, as well as photoluminescence spectra and their kinetics are found compatible with the model of excitons with heavy- and light-hole valence bands confined in nanoplatelets.

  5. Optical absorption, induced bleaching, and photoluminescence of CdSe nanoplatelets grown in cadmium octanoate matrix

    NASA Astrophysics Data System (ADS)

    Lyashchova, Alina; Dmytruk, Andriy; Dmitruk, Igor; Klimusheva, Gertruda; Mirnaya, Tetyana; Asaula, Vitaliy

    2014-02-01

    CdSe nanoparticles (NPs) are chemically synthesized in thermotropic ionic liquid crystalline (LC) phase of cadmium octanoate that was used as a nanoreactor. The nanocomposite samples are obtained by the rapid cooling of the LC phase to room temperature. Observed doublet structure in absorption spectra of the nanocomposites is characteristic for the two-dimensional CdSe nanoplatelets (NPLs). The thicknesses of the CdSe NPLs are 1.6, 1.9 and 2.3 nm as determined from the absorption spectra, and correspond to 4, 5 and 6 CdSe monolayers, respectively. Induced simultaneous bleaching of the doublet components observed under femtosecond laser excitation, as well as photoluminescence spectra and their kinetics are found compatible with the model of excitons with heavy- and light-hole valence bands confined in nanoplatelets.

  6. Growth of Single-Crystalline Cadmium Iodide Nanoplates, CdI2/MoS2 (WS2, WSe2) van der Waals Heterostructures, and Patterned Arrays.

    PubMed

    Ai, Ruoqi; Guan, Xun; Li, Jia; Yao, Kangkang; Chen, Peng; Zhang, Zhengwei; Duan, Xidong; Duan, Xiangfeng

    2017-03-28

    Two-dimensional layered materials (2DLMs) have attracted considerable recent interest for their layer-number-dependent physical and chemical properties, as well as potential technological opportunities. Here we report the synthesis of two-dimensional layered cadmium iodide (CdI2) nanoplates using a vapor transport and deposition approach. Optical microscopy and scanning electron microscopy studies show that the resulting CdI2 nanoplates predominantly adopt hexagonal and triangular morphologies with a lateral dimension of ∼2-10 μm. Atomic force microscopy studies show that the resulting nanoplates exhibit a thickness in the range of 5-220 nm with a relatively smooth surface. X-ray diffraction studies reveal highly crystalline CdI2 in hexagonal phase, which is also confirmed by the characteristic Raman Ag mode at 110 cm(-1). High-resolution transmission electron microscopy and selected area electron diffraction reveal that the resulting CdI2 nanoplates are single crystals. Taking a step further, we show the CdI2 nanoplates were readily grown on other 2DLMs (e.g., WS2, WSe2, MoS2), forming diverse van der Waals heterostructures. Using prepatterned WS2 monolayer square arrays as the nucleation and growth templates, we also show that regular arrays of CdI2/WS2 vertical heterostructures can be prepared. The synthesis of the CdI2 nanoplates, heterostructures, and heterostructure arrays offers a valuable material system for 2D materials science and technology.

  7. Cadmium-zinc accumulation and photosystem II responses of Noccaea caerulescens to Cd and Zn exposure.

    PubMed

    Bayçu, Gülriz; Gevrek-Kürüm, Nurbir; Moustaka, Julietta; Csatári, István; Rognes, Sven Erik; Moustakas, Michael

    2017-01-01

    A population of the metallophyte Noccaea (Thlaspi) caerulescens originating from a Zn-enriched area at Røros Copper Mine (Norway) was studied. N. caerulescens tolerance to accumulate Cd and Zn was evaluated in hydroponic experiments by chlorophyll fluorescence imaging analysis. In the field-collected N. caerulescens mother plants, Zn shoot concentrations were above Zn hyperaccumulation threshold while, in hydroponic experiments under 40-μM Cd exposure, shoot Cd concentrations were clearly above Cd hyperaccumulation threshold. Cadmium ions and, to a less extent, Zn were mainly retained in the roots. Exposure to Cd enhanced Zn translocation to the shoot, while decreased significant total Ca(2+) uptake, suggesting that Cd uptake occurs through Ca(2+) transporters. Nevertheless, it increased Ca(2+) translocation to the leaf, possibly for photoprotection of photosystem II (PSII). Exposure to 800 μM Zn or 40 μM Cd resulted in increased Fe(3+) uptake suggesting that in N. caerulescens, Cd uptake does not take place through the pathway of Fe(3+) uptake and that conditions that lead to Cd and Zn accumulation in plants may also favor Fe accumulation. Despite the significant high toxicity levels of Zn and Cd in leaves, under Zn and Cd exposure, respectively, the allocation of absorbed light energy at PSII did not differ compared to controls. The results showed that N. caerulescens keep Cd and Zn concentrations in the mesophyll cells in non-toxic forms for PSII and that the increased Ca and Fe accumulation in leaves alleviates the toxicity effects. Chlorophyll fluorescence imaging revealed that PSII of N. caerulescens resisted better the phytotoxic effects of 20 times higher Zn than Cd exposure concentration. Overall, it is concluded that the use of chlorophyll fluorescence imaging constitutes a promising basis for investigating heavy metal tolerance of plants.

  8. Cadmium (Cd) distribution and contamination in Chinese paddy soils on national scale.

    PubMed

    Liu, Xiaojuan; Tian, Guangjin; Jiang, Dong; Zhang, Chi; Kong, Lingqiang

    2016-09-01

    Rice is a staple food by an increasing number of people in China. As more issues have arisen in China due to rice contaminated by cadmium (Cd), Cd contamination in arable soils has become a severe problem. In China, many studies have examined Cd contamination in arable soils on a national scale, but little studies have focused on the distribution of Cd in paddy fields. This study explored the spatial pattern of Cd in paddy soils in China, made a preliminary evaluation of the potential risk, and identified the most critically contaminated regions based on the domestic rough rice trade flow. The results showed that Cd concentrations in paddy soils in China ranged from 0.01 to 5.50 mg/kg, with a median value of 0.23 mg/kg. On average, the highest Cd concentrations were in Hunan (0.73 mg/kg), Guangxi (0.70 mg/kg), and Sichuan (0.46 mg/kg) provinces. Cd concentrations in paddy soils in central and western regions were higher than those in eastern regions, especially the southeastern coastal regions. Of the administrative regions, Cd standard exceedance rate was 33.2 %, and the heavy pollution rate was 8.6 %. Regarding to Cd of paddy soil, soil environmental quality was better in Northeast China Plain than in Yangtze River Basin and southeastern coastal region. Mining activities were the main anthropogenic pollution source of Cd in Chinese paddy soil. Based on rice trade, more of the Chinese population would be exposed to Cd through intake of rice produced in Hunan province. Certain regions that output rice, especially Hunan province, should be given priority in the management and control of Cd contamination in paddy soil.

  9. Modeling Mercury Cadmium Telluride (HgCdTe) Photodiodes

    DTIC Science & Technology

    2009-11-01

    and Electron Devices Directorate, ARL and Dragica Vasileska Arizona State University, Tempe AZ 85287-5706...coefficient of Hg1–xCdxTe as a function of composition x (4). ......3 Figure 3. Comparison of the bandgap vs. lattice constant variation with alloy...proceeded deliberately and steadily for four decades in spite of the high vapor pressure of Hg at the melting point of HgCdTe and the known toxicity

  10. Development of Novel Cadmium-Free AgInS2 Semiconductor Nanoparticles.

    PubMed

    Yang, Wentao; Gong, Xiaoqun; Chang, Jin

    2016-03-01

    AgInS2 (AIS) semiconductor nanoparticles as the novel alternatives to cadmium- or lead-containing semiconductors have attracted much attention both on the theory and application research, based on their tunable fluorescence emission wavelengths, high photostability and low toxicity of chemical composition. The bandgap of AIS nanoparticles can be adjusted from 1.54 to 2.03 eV, which makes AIS nanocrystalline suitable for applications in solar energy conversion. Moreover, the fluorescence emission wavelengths can be tuned in the near-infrared regions, and thus make it the next-generation low-toxicity materials for the applications in bioimaging. In this review, the research progress of the AIS nanoparticles is summarized, including synthetic methods, properties and the possibilities to influence their shape and crystallographic structure. Furthermore, we discuss the potential applications of this novel material in photocatalysis, solar energy conversion and biological area.

  11. Metal Contacts to Cadmium Telluride (CdTe).

    DTIC Science & Technology

    1987-10-01

    WILLIAMS, I.M. DHARMADASA, M.H. PATTERSON’, C. MAANI** and N.M. FORSYTH Physics Deparment, University College, PO Box 78, Cardiff, UK Received 10 June 1985...North-Holland Physics Publishing Division) -43- 324 R. H. Williams et al. / Metal contacts to InP and CdTe considerations of local charge neutrality near...support. References Ill L.J. Brillson. Surface Sci. Rept. 2 (1982) 123. 121 R.H. Williams. Proc. 17th Intern. Conf. on the Physics of Semiconductors

  12. Development of radiopure cadmium tungstate crystal scintillators from enriched {sup 106}Cd and {sup 116}Cd to search for double beta decay

    SciTech Connect

    Danevich, F. A.; Boiko, R. S.; Chernyak, D. M.; Kobychev, V. V.; Kropivyansky, B. N.; Mokina, V. M.; Nikolaiko, A. S.; Poda, D. V.; Podviyanuk, R. B.; Tretyak, V. I.; Barabash, A. S.; Konovalov, S. I.; Umatov, V. I.; Belli, P.; Bernabei, R.; D'Angelo, S.; Brudanin, V. B.; Cappella, F.; Incicchitti, A.; Caracciolo, V.; and others

    2013-08-08

    Cadmium tungstate crystal scintillators enriched in {sup 106}Cd up to 66% ({sup 106}CdWO{sub 4}) and in {sup 116}Cd up to 82% ({sup 116}CdWO{sub 4}) have been developed. The low radioactive contamination of the crystals measured on the level of ≤ 1.5 mBq/kg ({sup 40}K), ≤ 0.005 - 0.012 mBq/kg ({sup 226}Ra), 0.04 - 0.07 mBq/kg ({sup 228}Th) allows to carry out high sensitivity experiments to search for double beta processes in {sup 106}Cd and {sup 116}Cd.

  13. Effect of plant growth-promoting rhizobacteria inoculation on cadmium (Cd) uptake by Eruca sativa.

    PubMed

    Kamran, Muhammad Aqeel; Syed, Jabir Hussain; Eqani, Syed Ali Musstjab Akber Shah; Munis, Muhammad Farooq Hussain; Chaudhary, Hassan Javed

    2015-06-01

    Microbe-assisted phyto-remediation approach is widely applied and appropriate choice to reduce the environmental risk of heavy metals originated from contaminated soils. The present study was designed to screen out the nested belongings of Eruca sativa plants and Pseudomonas putida (ATCC 39213) at varying cadmium (Cd) levels and their potential to deal with Cd uptake from soils. We carried out pot trial experiment by examining the soil containing E. sativa seedlings either treated with P. putida and/or untreated plants subjected to three different levels (ppm) of Cd (i.e., 150, 250, and 500). In all studied cases, we observed an increase in Cd uptake for E. sativa plants inoculated with P. putida than those of un-inoculated plants. Cd toxicity was assessed by recording different parameters including stunted shoot growth, poor rooting, and Cd residual levels in the plants that were not inoculated with P. putida. Significant difference (p < 0.05) of different growth parameters for inoculated vs non-inoculated plants was observed at all given treatments. However, among the different treatments, E. sativa exhibited increased values for different growth parameters (except proline contents) at lower Cd levels than those of their corresponding higher levels, shoot length (up to 27 %), root length (up to 32 %), whole fresh plant (up to 40 %), dry weight (up to 22 %), and chlorophyll contents (up to 26 %). Despite the hyperaccumulation of Cd in whole plant of E. sativa, P. putida improved the plant growth at varying levels of Cd supply than those of associated non-inoculated plants. Present results indicated that inoculation with P. putida enhanced the Cd uptake potential of E. sativa and favors the healthy growth under Cd stress.

  14. Desferrioxamine-cadmium as a 'Trojan horse' for the delivery of Cd to bacteria and fungi.

    PubMed

    Mattos, Ana Luiza Costa; Constantino, Vera Regina Leopoldo; de Couto, Ricardo Alexandre Alves; Pinto, Delia Manuela Luna; Kaneko, Telma Mary; Espósito, Breno Pannia

    2013-04-01

    Molecules naturally designed for the acquisition of essential metals can be used as a shuttle to deliver toxic metal ions to target organisms. In this study, we describe for the first time the synthesis of a derivative of cadmium and desferrioxamine B, a bacterial siderophore. The new compound was characterized by elemental analysis, vibrational (infrared and Raman) spectroscopy, mass coupled thermal analyses and X-ray diffraction methods. Studies on the in vitro toxicity toward a fungus and two bacterial strains indicated that the coordination compound is more active against microrganisms than cadmium chloride on a Cd-concentration basis, indicating that desferrioxamine can work as a "Trojan horse" in the delivery of a toxic metal.

  15. Transcriptome Sequencing and Expression Analysis of Cadmium (Cd) Transport and Detoxification Related Genes in Cd-Accumulating Salix integra

    PubMed Central

    Shi, Xiang; Sun, Haijing; Chen, Yitai; Pan, Hongwei; Wang, Shufeng

    2016-01-01

    Salix integra is a shrub willow native to northeastern China, Japan, Korea, and Primorsky Krai in the far southeast of Russia, and has been identified as cadmium (Cd)-accumulating trees in recent years. Although many physiological studies have been conducted with these plants, little is known about the molecular basis underlying Cd response in this plant, and this is confirmed by the very few number of gene sequences (only 39 nucleotide sequences) available in public databases. Advances in genomics for Salix are promising for future improvement in identification of new candidate genes involved in metal tolerance and accumulation. Thus, high-throughput transcriptome sequencing is essential for generating enormous transcript sequences from S. integra, especially for the purpose of Cd toxicity-responsive genes discovery. Using Illumina paired-end sequencing, approximately 60.05 million high-quality reads were obtained. De novo assembly yielded 80,105 unigenes with an average length of 703 bp, A total of 50,221 (63%) unigenes were further functionally annotated by comparing their sequences to different proteins and functional domain databases. GO annotation reveals 1849 Cd responsive genes involving in Cd binding, transport, and detoxification and cellular Cd homeostasis, and these genes were highly enriched in plant response to Cd ion and Cd ion transport. By searching against the PlantCyc database, 509 unigenes were assigned to 14 PlantCyc pathways related to Cd transport and cellular detoxification, and many of them are genes encoding heavy metal ATPases (HMAs), nature resistance-associated with microphage proteins (NRAMPs), ATP-binding cassette (ABC) transporters, etc., Comprehensive RT-qPCR analysis of these selected genes in different tissues of S. integra under the control and Cd treatment revealed metallothionein-like protein (MT2A and MT2B), Metal tolerance protein (MTP1), ABCB25, NRAMP5, and ZIP1 may be involved in the Cd transport and detoxification in

  16. Transcriptome Sequencing and Expression Analysis of Cadmium (Cd) Transport and Detoxification Related Genes in Cd-Accumulating Salix integra.

    PubMed

    Shi, Xiang; Sun, Haijing; Chen, Yitai; Pan, Hongwei; Wang, Shufeng

    2016-01-01

    Salix integra is a shrub willow native to northeastern China, Japan, Korea, and Primorsky Krai in the far southeast of Russia, and has been identified as cadmium (Cd)-accumulating trees in recent years. Although many physiological studies have been conducted with these plants, little is known about the molecular basis underlying Cd response in this plant, and this is confirmed by the very few number of gene sequences (only 39 nucleotide sequences) available in public databases. Advances in genomics for Salix are promising for future improvement in identification of new candidate genes involved in metal tolerance and accumulation. Thus, high-throughput transcriptome sequencing is essential for generating enormous transcript sequences from S. integra, especially for the purpose of Cd toxicity-responsive genes discovery. Using Illumina paired-end sequencing, approximately 60.05 million high-quality reads were obtained. De novo assembly yielded 80,105 unigenes with an average length of 703 bp, A total of 50,221 (63%) unigenes were further functionally annotated by comparing their sequences to different proteins and functional domain databases. GO annotation reveals 1849 Cd responsive genes involving in Cd binding, transport, and detoxification and cellular Cd homeostasis, and these genes were highly enriched in plant response to Cd ion and Cd ion transport. By searching against the PlantCyc database, 509 unigenes were assigned to 14 PlantCyc pathways related to Cd transport and cellular detoxification, and many of them are genes encoding heavy metal ATPases (HMAs), nature resistance-associated with microphage proteins (NRAMPs), ATP-binding cassette (ABC) transporters, etc., Comprehensive RT-qPCR analysis of these selected genes in different tissues of S. integra under the control and Cd treatment revealed metallothionein-like protein (MT2A and MT2B), Metal tolerance protein (MTP1), ABCB25, NRAMP5, and ZIP1 may be involved in the Cd transport and detoxification in

  17. Electrostatic assembles and optical properties of Au CdTe QDs and Ag/Au CdTe QDs

    NASA Astrophysics Data System (ADS)

    Yang, Dongzhi; Wang, Wenxing; Chen, Qifan; Huang, Yuping; Xu, Shukun

    2008-09-01

    Au-CdTe and Ag/Au-CdTe assembles were firstly investigated through the static interaction between positively charged cysteamine-stabilized CdTe quantum dots (QDs) and negatively charged Au or core/shell Ag/Au nano-particles (NCs). The CdTe QDs synthesized in aqueous solution were capped with cysteamine which endowed them positive charges on the surface. Both Au and Ag/Au NCs were prepared through reducing precursors with gallic acid obtained from the hydrolysis of natural plant poly-phenols and favored negative charges on the surface of NCs. The fluorescence spectra of CdTe QDs exhibited strong quenching with the increase of added Au or Ag/Au NCs. Railey resonance scattering spectra of Au or Ag/Au NCs increased firstly and decreased latter with the concentration of CdTe QDs, accompanied with the solution color changing from red to purple and colorless at last. Experimental results on the effects of gallic acid, chloroauric acid tetrahydrate and other reagents demonstrated the static interaction occurred between QDs and NCs. This finding reveals the possibilities to design and control optical process and electromagnetic coupling in hybrid structures.

  18. The chemistry and structure of ?222? CdO/Ag heterophase interfaces on an atomic scale

    NASA Astrophysics Data System (ADS)

    Chan, D. K.; Seidman, D. N.; Merkle, K. L.

    1996-03-01

    The chemistry and structure of {222} CdO/Ag (ceramic/metal) heterophase interfaces are determined with sub-nanometer chemical and structural spatial resolution employing atom-probe field-ion and high-resolution electron microscopies. The interfaces are produced in a controlled manner via internal oxidation of a Ag1.62at%Cd alloy, which results in the formation of CdO precipitates in a Ag matrix. The CdO precipitates are octahedral-shaped with facets on the {222} polar planes, and have a cube-on-cube orientation relationship with the Ag matrix. Atom-probe analyses are made along the chemically-ordered CdO <111>-type directions, thereby perpendicularly intersecting the {222} interfaces. A total of 35 {222} heterophase interfaces is chemically analyzed, of which 19 have the chemical sequence Ag|O|Cd|… and 16 the sequence Ag|Cd|O|…. High resolution electron microscopy analyses reveal that the {222} facet planes of the CdO precipitates con atomic height ledges, therefore indicating that the preciptates were in a coarsening stage. The combined atom-probe and high-resolution electron microscope results demonstrate that the chemistry of the terminating {222} facet plane of CdO is controlled by coarsening kinetics.

  19. Effect of biochars and microorganisms on cadmium accumulation in rice grains grown in Cd-contaminated soil.

    PubMed

    Suksabye, Parinda; Pimthong, Apinya; Dhurakit, Prapai; Mekvichitsaeng, Phenjun; Thiravetyan, Paitip

    2016-01-01

    Cadmium (Cd) contaminated in rice grains is a serious problem because most Asians consume rice on a daily basis. Rice grown in Cd-contaminated soil normally did not have high concentration of Cd. However, soil samples used in this study had high concentrations of Cd. The purpose of this study was to clearly see the effects of biochar and microorganism addition in rice growing in Cd-contaminated soil. The initial Cd concentration in Cd-contaminated soil used in this study was about 650 mg kg(-1). Cadmium concentration in rice plants grown in Cd-contaminated soil with the addition of 1% (w/w) different biochars such as sawdust fly ash (SDFA), bagasse fly ash (BGFA), and rice husk ash (RHA) was investigated. The results showed that SDFA was the best biochar in terms of reducing cadmium accumulation in rice grains when compared to BGFA and RHA under the same conditions. In addition, rice plants grown in Cd-contaminated soil with the addition of various nonpathogenic microorganisms, such as Pseudomonas aeruginosa, Bacillus subtilis, and Beauveria bassiana were also studied. The results showed that the addition of 2% (v/v) microorganisms can reduce Cd accumulation in grains. It was found that grains obtained from Cd-contaminated soil with the addition of P. aeruginosa had the lowest cadmium concentration compared to the ones from soil amended with other strains. This was due to the fact that P. aeruginosa adsorbed more Cd itself into its cells than other strains. The rice plants grown in Cd-contaminated soil with the addition of biochars and microorganisms were also compared. The results showed that adding 2% (v/v) microorganisms seemed to reduce Cd accumulation in rice grains better than adding 1% (w/w) biochars. In addition, the amounts of calcium and magnesium in rice grains and the dry weight of plant in Cd-contaminated soil amended with P. aeruginosa were the highest in comparison to other microorganisms, biochars, and the soil without any amendments (Cd

  20. Catalytic solid substrate-room-temperature phosphorimetry detection for trace cadmium with Cd2+ -3.5-generation polyamidoamine dendrimer-Tween-80 complex.

    PubMed

    Liu, Jia-Ming; Wang, Hong-Xin; Lin, Li-Ping; Lin, Shao-Qin; Lin, Xuan; Cai, Wen-Lian; Lin, Chang-Qing; Li, Zhi-Ming

    2012-01-01

    3.5-Generation polyamidoamine dendrimers (3.5-G-D) emitted strong and stable room-temperature phosphorescence (RTP) on filter paper when Pb2+ was used as a heavy atom perturber. The RTP signal of 3.5-G-D was sharply enhanced upon the formation of 3.5-G-D-Tween-80 micelle compound. The complex Cd2+ -3.5-G-D-Tween-80, generated in the coordination reaction between Cd2+ and the tertiary amidocyanogen on the outer layer of 3.5-G-D in 3.5-G-D-Tween-80 micelle compound, could catalyze KBrO3 to oxidize 3.5-G-D in 3.5-G-D-Tween-80, which caused the sharp quenching of the RTP signal of the system. The phosphorescence intensity change (ΔI(p) ) of the system had a linear relationship with the content of Cd2+. Thus a new catalytic solid substrate-room-temperature phosphorimetry (SS-RTP) for the determination of trace cadmium has been established. This highly selective and sensitive method has been applied to determine trace cadmium in biological samples with a limit of detection (LD) of 1.2 ag per spot (when the sample volume was 0.4 μL per spot, the corresponding concentration was 3.0 × 10(-15)  g mL(-1) ), the results agreeing with those obtained by atomic absorption spectrometry. The mechanism of catalytic SS-RTP for the determination of trace cadmium was also discussed.

  1. An evaluation of potentially useful separator materials for nickel-cadmium (Ni-Cd] satellite batteries

    NASA Technical Reports Server (NTRS)

    Baker, H. A.; Toner, S. D.; Cuthrell, W. F.

    1974-01-01

    An evaluation intended to determine the potential suitability and probable efficacy of a group of separator materials for use in nickel-cadmium (Ni-Cd) satellite batteries was carried out. These results were obtained using test procedures established in an earlier evaluation of other separator materials, some of which were used in experimental battery cells subjected to simulated use conditions. The properties that appear to be most important are: high electrolyte absorptivity, good electrolyte retention, low specific resistivity, rapid wettability and low resistance to air permeation. Wicking characteristics and wet-out time seem to be more important with respect to the initial filling of the battery with the electrolyte.

  2. Cadmium

    Integrated Risk Information System (IRIS)

    Cadmium ; CASRN 7440 - 43 - 9 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effects

  3. Influence of Ag doping concentration on structural and optical properties of CdS thin film

    SciTech Connect

    Kumar, Pragati; Saxena, Nupur; Gupta, Vinay; Agarwal, Avinash

    2015-05-15

    This work shows the influence of Ag concentration on structural properties of pulsed laser deposited nanocrystalline CdS thin film. X-ray photoelectron spectroscopy (XPS) studies confirm the dopant concentration in CdS films and atomic concentration of elements. XPS studies show that the samples are slightly sulfur deficient. GAXRD scan reveals the structural phase transformation from cubic to hexagonal phase of CdS without appearance of any phase of CdO, Ag{sub 2}O or Ag{sub 2}S suggesting the substitutional doping of Ag ions. Photoluminescence studies illustrate that emission intensity increases with increase in dopant concentration upto 5% and then decreases for higher dopant concentration.

  4. Loading Ag nanoparticles on Cd(II) boron imidazolate framework for photocatalysis

    NASA Astrophysics Data System (ADS)

    Liu, Min; Zhang, De-Xiang; Chen, Shumei; Wen, Tian

    2016-05-01

    An amine-functionalized Cd(II) boron imidazolate framework (BIF-77) with three-dimensional open structure has been successfully synthesized, which can load Ag nanoparticles (NPs) for photocatalytic degradation of methylene blue (MB).

  5. Cadmium sulfate and CdTe-quantum dots alter DNA repair in zebrafish (Danio rerio) liver cells

    SciTech Connect

    Tang, Song; Cai, Qingsong; Chibli, Hicham; Allagadda, Vinay; Nadeau, Jay L.; Mayer, Gregory D.

    2013-10-15

    Increasing use of quantum dots (QDs) makes it necessary to evaluate their toxicological impacts on aquatic organisms, since their contamination of surface water is inevitable. This study compares the genotoxic effects of ionic Cd versus CdTe nanocrystals in zebrafish hepatocytes. After 24 h of CdSO{sub 4} or CdTe QD exposure, zebrafish liver (ZFL) cells showed a decreased number of viable cells, an accumulation of Cd, an increased formation of reactive oxygen species (ROS), and an induction of DNA strand breaks. Measured levels of stress defense and DNA repair genes were elevated in both cases. However, removal of bulky DNA adducts by nucleotide excision repair (NER) was inhibited with CdSO{sub 4} but not with CdTe QDs. The adverse effects caused by acute exposure of CdTe QDs might be mediated through differing mechanisms than those resulting from ionic cadmium toxicity, and studying the effects of metallic components may be not enough to explain QD toxicities in aquatic organisms. - Highlights: • Both CdSO{sub 4} and CdTe QDs lead to cell death and Cd accumulation. • Both CdSO{sub 4} and CdTe QDs induce cellular ROS generation and DNA strand breaks. • Both CdSO{sub 4} and CdTe QDs induce the expressions of stress defense and DNA repair genes. • NER repair capacity was inhibited with CdSO{sub 4} but not with CdTe QDs.

  6. Operating mechanism of electrically bistable memory device based on Ag doped CdSe/PVA nanocomposite

    NASA Astrophysics Data System (ADS)

    Kaur, Ramneek; Tripathi, S. K.

    2015-06-01

    This paper reports the fabrication and characterization of electrically bistable memory device with device structure Al/Ag doped CdSe/PVA nanocomposite/Ag. Current-Voltage (I-V) measurements show two conductivity states at the same applied voltage indicating the bistability behavior. The possible operating mechanism for the memory effects has been described. During transition from the low resistance state to high resistance state, the current follows the change from the injection emission to the space charge limited conduction mechanism. The achieved results demonstrate that the device based on Ag doped CdSe/PVA nanocomposite has a potential for future non-volatile memory devices.

  7. Cadmium-sulfide crystallites in Cd-. gamma. -glutamyl peptide complexes from Lycopersicon and Daucus

    SciTech Connect

    Reese, R.N. ); Winge, D.R. )

    1989-04-01

    Hydroponically-grown tomato plants (Lycopersicon esculentum P. Mill. cv stone) and suspension-cultured carrot cells (Daucus carota L.) exposed to 100 {mu}M cadmium salts produced metal-{gamma}-glutamyl peptide complexes containing acid labile sulfur. The properties of the complexes resemble the Cd-{gamma}-glutamyl complexes from Schizosaccharomyces pombe and Candida glabrata, known to contain a CdS crystallite core. The crystallite core is stabilized by a coating of peptides of the general structure ({gamma}-Glu-Cys){sub n}-Gly. The Cd-peptide complexes contain predominantly peptides of n{sub 2}, n{sub 3}, n{sub 4} and n{sub 3}desGly. Zn-peptide complexes were also isolated from carrot cultures grown in MS medium supplemented with 2 mM Zn and cysteine. Results of preliminary characterization of these complexes are consistent with the presence of a colloidal particle similar to that of the Cd-complexes.

  8. Cadmium in the waters off South Morocco: Nature of particles hosting Cd and insights into the mechanisms fractionating Cd from phosphate

    NASA Astrophysics Data System (ADS)

    Waeles, Matthieu; Planquette, Hélène; Afandi, Imane; Delebecque, Nina; Bouthir, Fatimazohra; Donval, Anne; Shelley, Rachel U.; Auger, Pierre-Amaël.; Riso, Ricardo D.; Tito de Morais, Luis

    2016-05-01

    In this study, we report the distributions of total dissolvable cadmium and particulate cadmium from 27 stations in southern Moroccan coastal waters (22°N-30°N), which is part of the North-West African upwelling system. These distributions were predominantly controlled by upwelling of the North Atlantic Central Waters (NACWs) and uptake by primary production. Atmospheric inputs and phosphogypsum slurry inputs from the phosphate industry at Jorf Lasfar (33°N), recently estimated as an important source of dissolved cadmium (240 t Cd yr-1), are at best of minor importance for the studied waters. Our study provides new insights into the mechanisms fractionating cadmium from phosphate. In the upper 30 m, the anomalies observed in terms of Cd:P ratios in both the particulate and total dissolvable fractions were related to an overall preferential uptake of phosphate. We show that the type of phytoplanktonic assemblage (diatoms versus dinoflagellates) is also a determinant of the fractionation intensity. In subsurface waters (30-60 m), a clear preferential release of P (versus Cd) was observed indicating that remineralization in Oxygen Minimum Zones is a key process in sequestering Cd.

  9. Underpotential deposition of Cd on Ag(1 1 1): an in situ STM study

    NASA Astrophysics Data System (ADS)

    García, S. G.; Salinas, D. R.; Staikov, G.

    2005-02-01

    The kinetics and mechanism of Cd underpotential deposition (UPD) and involved surface alloy formation processes in the system Ag(1 1 1)/Cd 2+, SO42-, are studied by means of combined electrochemical measurements and in situ scanning tunneling microscopy (STM). The results show that the UPD process starts with a formation of an expanded (diluted) adlayer with a superlattice structure Ag(1 1 1)- (√{3}×√{19})R23.4°. In the underpotential range 50 mV < Δ E < 80 mV this adlayer transforms to a condensed close packed Cd monolayer via a first order phase transition. At long polarization times the condensed monolayer undergoes structural changes involving place exchange processes between Cd atoms and surface Ag atoms. A formation of a second Cd monolayer and a significant Ag-Cd surface alloying take place at lower underpotentials (Δ E < 50 mV). The kinetics of surface alloying are analyzed on the basis of a recently proposed diffusion model including a relatively fast initial formation of a very thin surface alloy film and a subsequent slow alloy growth controlled by solid state diffusion. The anodic dealloying results in an appearance of monatomically deep pits, which disappear quickly at relatively high underpotentials (Δ E > 550 mV) indicating a high mobility of surface Ag atoms.

  10. Probing metabolic stability of CdSe nanoparticles: alkaline extraction of free cadmium from liver and kidney samples of rats exposed to CdSe nanoparticles

    PubMed Central

    Arslan, Zikri; Ates, Mehmet; McDuffy, Wanaki; Agachan, M. Sabri; Farah, Ibrahim O.; Yu, W. William; Bednar, Anthony J.

    2011-01-01

    Cadmium selenide nanoparticles (CdSe NPs) exhibit novel optoelectronic properties for potential biomedical applications. However, their metabolic stability is not fully understood because of the difficulties in measurement of free Cd from biological tissues of exposed individuals. In this study, alkaline dissolution with tetramethylammonium hydroxide (TMAH) is demonstrated for selective determination of free Cd and intact NPs from liver and kidney samples of animals that were exposed to thiol-capped CdSe NPs. Aqueous suspensions of CdSe NPs (3.2 nm) were used to optimize the conditions for extracting free Cd without affecting NPs. Nanoparticles were found to aggregate when heated in TMAH without releasing any significant Cd to solution. Performance of the method in discriminating free Cd and intact NPs were verified by Dogfish Liver (DOLT-4) certified reference material. The samples from the animals were digested in 4 mL TMAH at 70 °C to extract free Cd followed by analysis of aqueous phase by ICP-MS. Both liver and kidney contained significant levels of free Cd. Total Cd was higher in the liver, while kidney accumulated mostly free Cd such that up to 47.9% of total Cd in the kidney was free Cd when NPs were exposed to UV-light before injection. PMID:21700388

  11. Complete genome sequence of the Streptomyces sp. strain CdTB01, a bacterium tolerant to cadmium.

    PubMed

    Zhou, Geng; Yang, Hui; Zhou, Hui; Wang, Chong; Fu, Fuhua; Yu, Ye; Lu, Xiangyang; Tian, Yun

    2016-07-10

    Streptomyces sp. Strain CdTB01, which is tolerant to high concentrations of heavy metals, particularly cadmium, was isolated from soil contaminated with heavy metals. Two contigs with total genome size of 10.19Mb were identified in the whole genome sequencing and assembly, and numerous homologous genes known to be involved in heavy metal resistance were found in the genome.

  12. Shape control of cadmium hydroxides (Cd(OH)2) sensitive to pH quenching depth and massive production of CdSe nanocrystals by their chemical transformation.

    PubMed

    Ko, Sungwook; Moon, Geon Dae; Lee, Jung-Pil; Park, Soojin; Jeong, Unyong

    2011-08-05

    This study demonstrates that the structure of cadmium hydroxides (Cd(OH)(2)) precipitated from a basic cadmium nitrate solution can be finely controlled by adjusting the pH of the precursor solution. The synthesis process involves only pouring the saturated solution into pure water to quench the pH and the total process is finished within 30 s. At a shallow pH quenching, the unstable nanoparticles turned into microparticles via a ripening process. Cd(OH)(2) was precipitated in the form of one-dimensional nanowires and then two-dimensional plates as the pH quenching was increased. At a large pH quenching, porous aggregates of Cd(OH)(2) were obtained due to the too fast precipitation. The ultrafine Cd(OH)(2) nanowires were readily transformed into CdSe chain-like nanocrystals. The transformation was quick and gave 100% yield, facilitating massive production of CdSe nanocrystals in an aqueous condition. The Cd(OH)(2) nanowires were directly grown on Si nanowires and transformed into CdSe chain-like nanocrystals, decorating the surface of each Si nanowire.

  13. Shape control of cadmium hydroxides (Cd(OH)2) sensitive to pH quenching depth and massive production of CdSe nanocrystals by their chemical transformation

    NASA Astrophysics Data System (ADS)

    Ko, Sungwook; Moon, Geon Dae; Lee, Jung-Pil; Park, Soojin; Jeong, Unyong

    2011-08-01

    This study demonstrates that the structure of cadmium hydroxides (Cd(OH)2) precipitated from a basic cadmium nitrate solution can be finely controlled by adjusting the pH of the precursor solution. The synthesis process involves only pouring the saturated solution into pure water to quench the pH and the total process is finished within 30 s. At a shallow pH quenching, the unstable nanoparticles turned into microparticles via a ripening process. Cd(OH)2 was precipitated in the form of one-dimensional nanowires and then two-dimensional plates as the pH quenching was increased. At a large pH quenching, porous aggregates of Cd(OH)2 were obtained due to the too fast precipitation. The ultrafine Cd(OH)2 nanowires were readily transformed into CdSe chain-like nanocrystals. The transformation was quick and gave 100% yield, facilitating massive production of CdSe nanocrystals in an aqueous condition. The Cd(OH)2 nanowires were directly grown on Si nanowires and transformed into CdSe chain-like nanocrystals, decorating the surface of each Si nanowire.

  14. Hydrometallurgical route to recover nickel, cobalt and cadmium from spent Ni-Cd batteries

    NASA Astrophysics Data System (ADS)

    Fernandes, Aline; Afonso, Julio Carlos; Bourdot Dutra, Achilles Junqueira

    2012-12-01

    In this work a hydrometallurgical route to recover nickel, cobalt and cadmium after leaching spent Ni-Cd batteries with hydrochloric acid was investigated. Co(II) and Cd(II) were both recovered by solvent extraction. Cd(II) was first extracted (99.7 wt.%) with pure tri-n-butylphosphate (TBP), in the original leachate acidity (5.1 mol L-1), in two stages at 25 °C with an aqueous/organic (A/O) phase ratio = 1 v/v. The Co(II) present in the raffinate (free acidity 4.1 mol L-1) was extracted with Alamine 336 or Alamine 304 (10 vol.% in kerosene) at 25 °C with an A/O ratio = 1 in two stages. 97.5 wt.% of Co(II) was extracted using Alamine 336 while only 90.4 wt.% was extracted in the case of Alamine 304. Ni(II) was isolated from the raffinate as oxalate after addition of ammonium oxalate at pH 2.

  15. Large stokes shift of Ag doped CdSe quantum dots via aqueous route.

    PubMed

    Huang, Jian; Jiang, Yang; Duan, Hongyan; Liu, Chao; Mi, Longfei; Lan, Xinzheng; Zhou, Hongyang; Zhong, Honghai

    2013-10-01

    Monodispersed and luminescent Ag-doped CdSe semiconductor quantum dots (d-dots) were synthesized by an aqueous route assisted with electrochemical preparation of Se source with 3-mercaptopropionic acid as stabilizer. The silver dopants were incorporated into the host crystals via cation-exchange mechanism. X-ray diffraction patterns revealed that the as-synthesized CdSe:Ag d-dots were well retained in the zinc blende structure. The CdSe:Ag d-dots that exhibited uniform size distribution and good crystallnity could be observed by High-resolution transmission electron microscopy (HRTEM), with average diameter of 2.7 nm. Successful doping was confirmed by X-ray photoelectron spectroscopy survey spectra. The peculiar Ag-related photoluminescence showed strong intensity, and at the same time, intrinsic band-edge exciton emission of CdSe QDs was suppressed. The dopant emission exhibited larger Stockes shift of - 0.51 eV than that of the band-gap emission, and varied from 546 to 583 nm by changing electrolytic time. Possible radiative recombination mechanism of the aqueous Ag-doped CdSe d-dots was discussed. The results demonstrated that doping can be an effective way to manipulate the optical properties of semiconductor nanocrystals.

  16. Biochar enhances the cadmium tolerance in spinach (Spinacia oleracea) through modification of Cd uptake and physiological and biochemical attributes.

    PubMed

    Younis, Uzma; Malik, Saeed Ahmad; Rizwan, Muhammad; Qayyum, Muhammad Farooq; Ok, Yong Sik; Shah, Muhammad Hasnain Raza; Rehman, Rabia Abdur; Ahmad, Niaz

    2016-11-01

    Cadmium (Cd) has no known role in plant biology and is toxic to plants and animals. The Cd mainly accumulated in agricultural soils through anthropogenic activities, such as sewage water irrigation and phosphorus fertilization. Biochar (BC) has been proposed as an amendment to reduce metal toxicity in plants. The objective of this study was to evaluate the role of BC (cotton stick at a rate of 0, 3, and 5 %) on Cd uptake and the photosynthetic, physiological, and biochemical responses of spinach (Spinacia oleracea) grown in Cd-spiked soil (0, 25, 50, 75, and 100 mg Cd kg(-1) soil). The results showed that Cd toxicity decreased growth, photosynthetic pigments, gas exchange characteristics, and amino acid and protein contents in 52-day-old spinach seedlings. The Cd treatments increased the concentrations of Cd, sugar, ascorbic acid, and malondialdehyde (MDA) in plants. The application of BC ameliorated the harmful effects of Cd in spinach plants. Under Cd stress, BC application increased the growth, photosynthesis, and protein contents and decreased Cd concentrations and MDA contents in plants. The maximum BC-mediated increase in dry biomass was about 25 % with 5 % BC application in control plants. It is concluded that BC could ameliorate Cd toxic effects in spinach through changing the physiological and biochemical attributes under Cd stress.

  17. Ag adsorption on Cd-terminated CdS (0 0 0 1) and S-terminated CdS (0 0 0 1-bar) surfaces: First-principles investigations

    SciTech Connect

    Ma, Yandong; Dai, Ying; Wei, Wei; Liu, Xianghong; Huang, Baibiao

    2011-04-15

    First-principles calculations are performed to study the adsorption of Ag at Cd-terminated CdS (0 0 0 1) and S-terminated CdS (0 0 0 1-bar) surfaces as a function of Ag coverage. Our results reveal that Ag adsorption at Cd-terminated (0 0 0 1) has a large binging energy than at S-terminated (0 0 0 1-bar) surface. For Ag adsorption at Cd-terminated (0 0 0 1) surface, T4 structure is more favorable and the Ag-Cd bond posses an ionic-like character. While for Ag adsorption at S-terminated (0 0 0 1-bar) surface, the H3 structure is most stable and the bonding between Ag-S is covalent. It is found that the magnitude and the sign of surface dipole moment are partly determined by the difference between the electronegativities of Ag and the host atom bonding with Ag. The adsorption energy changes as a function of Ag coverage. In addition, related properties of Ag cluster adsorption at Cd-terminated (0 0 0 1) surface are also discussed. -- Graphical abstract: We studied the adsorption of Ag at Cd-terminated CdS (0 0 0 1) and S-terminated CdS (0 0 0 1-bar) surfaces as a function of Ag coverage by means of the first-principles calculations. In addition, related properties of Ag cluster adsorption at Cd-terminated (0 0 0 1) surface are also discussed. Our ab initio calculations are useful complement to the intense experimental studies for Ag-CdS interface. Display Omitted Research highlights: {yields} Ag adsorption effects on electronic structure and associated physics properties of CdS is systemically studied. {yields} The surface dipole moment is partly determined by the difference between the electronegativities of silver and the host atom bonding with silver. {yields} The characteristic of Ag cluster (Ag{sub 2}, Ag{sub 4}, and Ag{sub 7}) adsorption on the CdS (0 0 0 1) surface is discussed.

  18. Facile Synthesis of Cadmium-Free Zn-In-S:Ag/ZnS Nanocrystals for Bio-Imaging

    PubMed Central

    Xuan, Tong-Tong; Liu, Jia-Qing; Yu, Cai-Yan; Xie, Rong-Jun; Li, Hui-Li

    2016-01-01

    High quality cadmium-free Zn-In-S:Ag doped-nanocrystals (d-NCs) were synthesized via a simple one-step noninjection route using silver nitrate, indium acetate, zinc acetate, oleylamine, S powder and 1-dodecanethiol as starting materials in an organic phase. The size and optical properties can be effectively tailored by controlling the reaction time, reaction temperature, Ag+ dopant concentration, and the molar ratio of In to Zn. The photoluminescence wavelength of as-prepared Zn-In-S:Ag NCs covered a broad visible range from 458 nm to 603 nm. After being passivated by protective ZnS shell, the photoluminescence quantum yield (PLQY) of Zn-In-S:Ag+ /ZnS was greatly improved to 43.5%. More importantly, the initial high PLQY of the obtained core/shell d-NCs in organic media can be preserved when being transferred into the aqueous media via ligand exchange. Finally, high quality Zn-In-S:Ag+ /ZnS d-NCs in aqueous phase were applied as bio-imaging agents for identifying living KB cells. PMID:27074820

  19. Ternary Solid Phase Equilibria in the Systems (Ag,In,Au)-(Cd,He)-Te

    DTIC Science & Technology

    1988-07-22

    thermochemnical data. In closed thermodynamic systems Ag,In, and Au were shown to be stable with respect to stoichiometric CdTe and Ag, In reactive towards...compositions within Codes Avail and/or 2lit Specilal the six ternary systems. Thermodynamic calculations were performed using the data collected in... Thermodynamic Properties of the Elements, (Amer.Chem.Soc., Washington, D.C., 1956) 11) John H. Pugh, Masters Thesis, UCLA, 1986-unpublished. 12) W.G

  20. Magnetic hyperfine interactions on Cd sites of the rare-earth cadmium compounds R Cd (R =Ce , Pr, Nd, Sm, Gd, Tb, Dy, Ho, and Er)

    NASA Astrophysics Data System (ADS)

    Cavalcante, F. H. M.; Leite Neto, O. F. L. S.; Saitovitch, H.; Cavalcante, J. T. P. D.; Carbonari, A. W.; Saxena, R. N.; Bosch-Santos, B.; Pereira, L. F. D.; Mestnik-Filho, J.; Forker, M.

    2016-08-01

    This paper reports the investigation of the magnetic hyperfine field Bh f in a series of rare-earth (R ) cadmium intermetallic compounds R Cd and GdCd2 measured by perturbed angular correlation (PAC) spectroscopy using 111In/111Cd as probe nuclei at Cd sites as well as first-principles calculations of Bh f at Cd sites in the studied compounds. Vapor-solid state reaction of R metals with Cd vapor and the 111In radioisotope was found to be an appropriate route of doping rare-earth cadmium compounds with the PAC probe 111In/111Cd. The observation that the hyperfine parameters depend on details of the sample preparation provides information on the phase preference of diffusing 111In in the rare-earth cadmium phase system. The 111Cd hyperfine field has been determined in the compounds R Cd for the R constituents Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, and Er, in several cases as a function of temperature. For most R constituents, the temperature dependence Bh f(T ) of 111Cd:R Cd is consistent with ferromagnetic order of the compound. DyCd, however, presents a remarkable anomaly: a finite magnetic hyperfine field is observed only in the temperature interval 35 K ≤ T ≤ 80 K which indicates a transition from ferromagnetic order to a spin arrangement where all 4 f -induced contributions to the magnetic hyperfine field at the Cd site cancel. First-principles calculation results for DyCd show that the (π , π , 0) antiferromagnetic configuration is energetically more favorable than the ferromagnetic. The approach used in the calculations to simulate the R Cd system successfully reproduces the experimental values of Bh f at Cd sites and shows that the main contribution to Bh f comes from the valence electron polarization. The de Gennes plot of the hyperfine field Bh f of 111Cd:R Cd vs the 4 f -spin projection (g -1 )J reflects a decrease of the strength of indirect 4 f -4 f exchange across the R series. Possible mechanisms are discussed and the experimental results indicate that

  1. Properties of reactively sputtered oxygenated cadmium sulfide (CdS:O) and their impact on CdTe solar cell performance

    SciTech Connect

    Meysing, Daniel M. Wolden, Colin A.; Griffith, Michelle M.; Mahabaduge, Hasitha; Pankow, Joel; Reese, Matthew O.; Burst, James M.; Rance, William L.; Barnes, Teresa M.

    2015-03-15

    Oxygenated cadmium sulfide (CdS:O) is commonly used as the n-type window layer in high-performance CdTe heterojunction solar cells. This layer is deposited by reactive sputtering, but the optimal amount of oxygen in the sputtering ambient is highly dependent on the specific system and process employed. In this work, the intrinsic properties of CdS:O were measured as a function of the oxygen content (0%–10%) in the sputtering ambient and correlated to device performance with the goal of better defining optimal CdS:O properties for CdTe solar cells. Optimal performance was found using CdS:O films that contained ∼40 at. % oxygen as measured by Rutherford backscattering spectrometry. X-ray photoelectron spectroscopy confirmed these results and showed that oxygen is incorporated primarily as oxygenated sulfur compounds (SO{sub x}). Device efficiency improved from 10.5% using CdS to >14% with CdS:O due largely to increases in short-circuit current density as well as a modest improvement in open-circuit voltage. The transparency of the CdS:O films was well correlated with observed improvements in blue quantum efficiency with increasing oxygen content. The optical bandgap of as-deposited CdS:O was identified as a simple metric for process optimization and transfer, with 2.8 eV being ideal for the device architecture employed.

  2. sup 113 Cd shielding tensors of the cadmium complex of texaphyrin, a novel expanded porphyrin, and its pyridine and benzimidazole adducts

    SciTech Connect

    Kennedy, M.A.; Ellis, P.D. ); Sessler, J.L.; Murai, Toshiaki )

    1990-03-07

    The cadmium complex of an expanded five-coordinate porphyrin known as texaphyrin and its complexes with pyridine and benzimidazole have been investigated by solution- and solid-state {sup 113}Cd NMR spectroscopy, and the results are reported. The principle shielding tensor elements were determined for each complex and are discussed in terms of reported crystal studies of Cd-texaphyrin and in comparison to cadmium complexes with other porphyrin and similar macrocycle ligands. 18 refs., 5 figs., 1 tab.

  3. Growth and photosynthetic limitation analysis of the Cd-accumulator Salicornia ramosissima under excessive cadmium concentrations and optimum salinity conditions.

    PubMed

    Pérez-Romero, Jesús Alberto; Redondo-Gómez, Susana; Mateos-Naranjo, Enrique

    2016-12-01

    Cadmium (Cd) is a non-essential element for plants, and its excess impairs plant performance. Physiological impacts of Cd excess are well known in non-tolerant plants, however this information is scarce for Cd-tolerant plants. A glasshouse experiment was designed to investigate the effect of five different Cd levels (0, 0.05, 0.20, 0.65 and 1.35 mM Cd) on the growth, photosynthetic apparatus (PSII chemistry), gas exchange characteristics, photosynthetic pigments profiles, water relations and nutritional balance of the Cd-accumulator Salicornia ramosissima. Ours results confirmed the accumulation capacity of S. ramosissima, as indicated the bioaccumulation factor (BC) greater than 1.0 for all Cd levels. Furthermore, after 21 days of treatment S. ramosissima growth was not highly affected by Cd. Total photosynthetic limitation increased from 38% at 0.05 mM Cd to 70% at 1.35 mM Cd. CO2 diffusion restriction imposed the main contribution to total photosynthetic limitation. Mesophyll conductance reduction was of major importance (with between 69 and 86%), followed by stomatal conductance (with between 9 and 20%). Maximum carboxylation rate (Vc,max), remained stable until 0.2 mM Cd, and chlorophyll fluorescence parameters (Fv/Fm, qP) and pigments concentrations were not significantly decreased by increased Cd supply. Finally, S. ramosissima water relations (intrinsic water use efficiency and relative water content) and nutritional level did not highly vary between Cd treatments. Thus, our finding suggested that Cd tolerance S. ramosissima is in certain degree supported by the tolerance of its carbon assimilation enzyme (RuBisCO) and with the high functionality and integrity of the PSII reaction center under Cd excess.

  4. Microbial toxicity of ionic species leached from the II-VI semiconductor materials, cadmium telluride (CdTe) and cadmium selenide (CdSe).

    PubMed

    Ramos-Ruiz, Adriana; Zeng, Chao; Sierra-Alvarez, Reyes; Teixeira, Luiz H; Field, Jim A

    2016-11-01

    This work investigated the microbial toxicity of soluble species that can potentially be leached from the II-VI semiconductor materials, cadmium telluride and cadmium selenide. The soluble ions tested included: cadmium, selenite, selenate, tellurite, and tellurate. Their toxicity towards the acetoclastic and hydrogen-consuming trophic groups in a methanogenic consortium as well as towards a bioluminescent marine bacterium, Aliivibrio fischeri (Microtox(®) test), was assessed. The acetoclastic methanogenic activity was the most affected as evidenced by the low 50% inhibiting concentrations (IC50) values obtained of 8.6 mg L(-1) for both cadmium and tellurite, 10.2 mg L(-1) for tellurate, and 24.1 mg L(-1) for selenite. Both tellurium oxyanions caused a strong inhibition of acetoclastic methanogenesis at low concentrations, each additional increment in concentration provided progressively less inhibition increase. In the case of the hydrogenotrophic methanogenesis, cadmium followed by selenite caused the greatest inhibition with IC50 values of 2.9 and 18.0 mg L(-1), respectively. Tellurite caused a moderate effect as evidenced by a 36.8% inhibition of the methanogenic activity at the highest concentration tested, and a very mild effect of tellurate was observed. Microtox(®) analyses showed a noteworthy inhibition of cadmium, selenite, and tellurite with 50% loss in bioluminescence after 30 min of exposure of 5.5, 171.1, and 458.6 mg L(-1), respectively. These results suggest that the leaching of cadmium, tellurium and selenium ions from semiconductor materials can potentially cause microbial toxicity.

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

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

    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.

  6. Modelling of zircaloy dissolution by molten (Ag, In, Cd) absorber alloy

    NASA Astrophysics Data System (ADS)

    Veshchunov, M. S.; Hofmann, P.

    1996-04-01

    Solid Zircaloy (Zry) is dissolved by molten (Ag, In, Cd) alloy at high temperatures. Results of detailed chemical-analytical examinations (integral and point analysis) of (Ag, In, Cd)/Zry reaction couples annealed at temperatures of 1100, 1150 and 1200°C in crucible tests demonstrate a homogeneous composition of the resulting liquid phase and prove that strong convective mixing of the liquid takes place in the course of the interactions. The theoretical model developed on the basis of the measured data explains the reasons for the observed convective mixing of the liquid phase and describes the kinetics of the (Ag, In, Cd)/Zry interactions leading to the saturation of the liquid phase with Zr. Two main parameters of the model are calculated: Zr concentration in the saturated melt and convective mass transfer coefficient in the liquid phase. The influence of an oxide layer on the (Ag, In, Cd)/Zry interactions is additionally studied and described by the developed model.

  7. Synthesis and enhanced fluorescence of Ag doped CdTe semiconductor quantum dots.

    PubMed

    Ding, Si-Jing; Liang, Shan; Nan, Fan; Liu, Xiao-Li; Wang, Jia-Hong; Zhou, Li; Yu, Xue-Feng; Hao, Zhong-Hua; Wang, Qu-Quan

    2015-02-07

    Doping with intentional impurities is an intriguing way to tune the properties of semiconductor nanocrystals. However, the synthesis of some specific doped semiconductor nanocrystals remains a challenge and the doping mechanism in this strongly confined system is still not clearly understood. In this work, we report, for the first time, the synthesis of stable and water-soluble Ag-doped CdTe semiconductor quantum dots (SQDs) via a facile aqueous approach. Experimental characterization demonstrated the efficient doping of the Ag impurities into the CdTe SQDs with an appropriate reaction time. By doping 0.3% Ag impurities, the Stokes shift is decreased by 120 meV, the fluorescence intensity is enhanced more than 3 times, the radiative rate is enhanced 4.2 times, and the non-radiative rate is efficiently suppressed. These observations reveal that the fluorescence enhancement in Ag-doped CdTe SQDs is mainly attributed to the minimization of surface defects, filling of the trap states, and the enhancement of the radiative rate by the silver dopants. Our results suggest that the silver doping is an efficient method for tuning the optical properties of the CdTe SQDs.

  8. Phytoavailability of Cadmium (Cd) to Pak Choi (Brassica chinensis L.) Grown in Chinese Soils: A Model to Evaluate the Impact of Soil Cd Pollution on Potential Dietary Toxicity

    PubMed Central

    Yang, Xiaoe; Xiao, Wendan; Stoffella, Peter J.; Saghir, Aamir; Azam, Muhammad; Li, Tingqiang

    2014-01-01

    Food chain contamination by soil cadmium (Cd) through vegetable consumption poses a threat to human health. Therefore, an understanding is needed on the relationship between the phytoavailability of Cd in soils and its uptake in edible tissues of vegetables. The purpose of this study was to establish soil Cd thresholds of representative Chinese soils based on dietary toxicity to humans and develop a model to evaluate the phytoavailability of Cd to Pak choi (Brassica chinensis L.) based on soil properties. Mehlich-3 extractable Cd thresholds were more suitable for Stagnic Anthrosols, Calcareous, Ustic Cambosols, Typic Haplustalfs, Udic Ferrisols and Periudic Argosols with values of 0.30, 0.25, 0.18, 0.16, 0.15 and 0.03 mg kg−1, respectively, while total Cd is adequate threshold for Mollisols with a value of 0.86 mg kg−1. A stepwise regression model indicated that Cd phytoavailability to Pak choi was significantly influenced by soil pH, organic matter, total Zinc and Cd concentrations in soil. Therefore, since Cd accumulation in Pak choi varied with soil characteristics, they should be considered while assessing the environmental quality of soils to ensure the hygienically safe food production. PMID:25386790

  9. Phytoavailability of cadmium (Cd) to Pak choi (Brassica chinensis L.) grown in Chinese soils: a model to evaluate the impact of soil Cd pollution on potential dietary toxicity.

    PubMed

    Rafiq, Muhammad Tariq; Aziz, Rukhsanda; Yang, Xiaoe; Xiao, Wendan; Stoffella, Peter J; Saghir, Aamir; Azam, Muhammad; Li, Tingqiang

    2014-01-01

    Food chain contamination by soil cadmium (Cd) through vegetable consumption poses a threat to human health. Therefore, an understanding is needed on the relationship between the phytoavailability of Cd in soils and its uptake in edible tissues of vegetables. The purpose of this study was to establish soil Cd thresholds of representative Chinese soils based on dietary toxicity to humans and develop a model to evaluate the phytoavailability of Cd to Pak choi (Brassica chinensis L.) based on soil properties. Mehlich-3 extractable Cd thresholds were more suitable for Stagnic Anthrosols, Calcareous, Ustic Cambosols, Typic Haplustalfs, Udic Ferrisols and Periudic Argosols with values of 0.30, 0.25, 0.18, 0.16, 0.15 and 0.03 mg kg-1, respectively, while total Cd is adequate threshold for Mollisols with a value of 0.86 mg kg-1. A stepwise regression model indicated that Cd phytoavailability to Pak choi was significantly influenced by soil pH, organic matter, total Zinc and Cd concentrations in soil. Therefore, since Cd accumulation in Pak choi varied with soil characteristics, they should be considered while assessing the environmental quality of soils to ensure the hygienically safe food production.

  10. Effects of cadmium-resistant fungi Aspergillus aculeatus on metabolic profiles of bermudagrass [Cynodondactylon (L.)Pers.] under Cd stress.

    PubMed

    Li, Xiaoning; Gitau, Margaret Mukami; Han, Shijuan; Fu, Jinmin; Xie, Yan

    2017-05-01

    Plants' tolerance to heavy metal stress may be induced by the exploitation of microbes. The objectives of this study were to investigate the effect of cadmium (Cd)-resistant fungus, Aspergillus aculeatus, on tolerance to Cd and alteration of metabolites in bermudagrass under Cd stress, and identify the predominant metabolites associated with Cd tolerance. Two genotypes of bermudagrass with contrasting Cd tolerance (Cd-sensitive 'WB92' and Cd-tolerant 'WB242') were exposed to 0, 50, 150 and 250 mg kg(-1) Cd for 21 days. Physiological responses of bermudagrass to Cd stress were evaluated based on the relative growth rate (RGR) and normalized relative transpiration rate (NRT). Plants inoculated with A. aculeatus exhibited higher RGR and NRT under Cd stress than those of non-inoculated plants, regardless of genotypes. A total of 32 Cd-responsive metabolites in leaves and 21 in roots were identified in the two genotypes, including organic acids, amino acids, sugars, and fatty acids and others. Interestingly, under Cd stress, the leaves of inoculated 'WB92' accumulated less citric acid, aspartic acid, glutamic acid, sucrose, galactose, but more sorbose and glucose, while inoculated 'WB242' leaves had less citric acid, malic acid, sucrose, sorbose, but more fructose and glucose, compared to non-inoculated plants. In 'WB92' roots, the A. aculeatus reduced mannose content, but increased trehalose and citric acid content, while in 'WB242', it decreased sucrose, but enhanced citric acid content, compared to Cd regime. The results of this study suggest that A. aculeatus may induce accumulation of different metabolites associated with Cd tolerance in bermudagrass.

  11. Data on HepG2 cells changes following exposure to cadmium sulphide quantum dots (CdS QDs).

    PubMed

    Paesano, Laura; Perotti, Alessio; Buschini, Annamaria; Carubbi, Cecilia; Marmiroli, Marta; Maestri, Elena; Iannotta, Salvatore; Marmiroli, Nelson

    2017-04-01

    The data included in this paper are associated with the research article entitled "Markers for toxicity to HepG2 exposed to cadmium sulphide quantum dots; damage to mitochondria" (Paesano et al.) [1]. The article concerns the cytotoxic and genotoxic effects of CdS QDs in HepG2 cells and the mechanisms involved. In this dataset, changes in expression levels of candidate genes are reported, together with details concerning synthesis and properties of CdS QDs, additional information obtained through literature survey, measures of the mitochondrial membrane potential and the glutathione redox state.

  12. Characterization of cadmium ((108)Cd) distribution and accumulation in Tagetes erecta L. seedlings: effect of split-root and of remove-xylem/phloem.

    PubMed

    Qin, Qin; Li, Xuemei; Wu, Haiyan; Zhang, Yinqiu; Feng, Qian; Tai, Peidong

    2013-11-01

    Tagetes erecta has a high potential for cadmium (Cd) phytoremediation. Through several hydroponic experiments, characteristics of (108)Cd distribution and accumulation were investigated in T. erecta with split -roots or removed xylem/phloem. The results showed that (108)Cd transport from roots to aboveground tissues showed the homolateral transport phenomenon in split-root seedlings. (108)Cd content of leaves on the +(108)Cd side and the -(108)Cd side was not significantly different, which implied that there was horizontal transport of (108)Cd from the +(108)Cd side to the -(108)Cd side in cut-root seedlings. Like (108)Cd transport, the transport of (70)Zn was homolateral. Reduction of water consumption in the removed xylem treatment significantly decreased (108)Cd accumulation; whereas, the removed phloem treatment had no significant effect on water consumption, but did decrease (108)Cd accumulation in leaves of the seedlings. The removal of phloem significantly reduced distal leaf (108)Cd content, which was significantly lower than that in the basal leaves in both the split-root and unsplit-root seedlings. Overall, the results presented in this study revealed that the root to aboveground cadmium translocation via phloem is as an important and common physiological process as xylem determination of the cadmium accumulation in stems and leaves of marigold seedlings.

  13. Local field-induced optical properties of Ag-coated CdS quantum dots.

    PubMed

    Je, Koo-Chul; Ju, Honglyoul; Treguer, Mona; Cardinal, Thierry; Park, Seung-Han

    2006-08-21

    Local field-induced optical properties of Ag-coated CdS quantum dot structures are investigated. We experimentally observe a clear exciton peak due to the quantum confinement effect in uncoated CdS quantum dots, and surface plasmon resonance and red-shifted exciton peak in Ag-coated CdS composite quantum dot structures. We have calculated the Stark shift of the exciton peak as a function of the local field for different silver thicknesses and various sizes of quantum dots based on the effective-mass Hamiltonian using the numerical-matrix-diagonalization method. Our theoretical calculations strongly indicate that the exciton peak is red-shifted in the metal-semiconductor composite quantum dots due to a strong local field, i.e., the quantum confined Stark effect.

  14. Synthesis and Structures of Cadmium Carboxylate and Thiocarboxylate Compounds with a Sulfur-Rich Coordination Environment: Carboxylate Exchange Kinetics Involving Tris(2-mercapto-1-t-butylimidazolyl)hydroborato Cadmium Complexes, [TmBut]Cd(O2CR)

    PubMed Central

    2016-01-01

    A series of cadmium carboxylate compounds in a sulfur-rich environment provided by the tris(2-tert-butylmercaptoimidazolyl)hydroborato ligand, namely, [TmBut]CdO2CR, has been synthesized via the reactions of the cadmium methyl derivative [TmBut]CdMe with RCO2H. Such compounds mimic aspects of cadmium-substituted zinc enzymes and also the surface atoms of cadmium chalcogenide crystals, and have therefore been employed to model relevant ligand exchange processes. Significantly, both 1H and 19F NMR spectroscopy demonstrate that the exchange of carboxylate groups between [TmBut]Cd(κ2-O2CR) and the carboxylic acid RCO2H is facile on the NMR time scale, even at low temperature. Analysis of the rate of exchange as a function of concentration of RCO2H indicates that reaction occurs via an associative rather than dissociative pathway. In addition to carboxylate compounds, the thiocarboxylate derivative [TmBut]Cd[κ1-SC(O)Ph] has also been synthesized via the reaction of [TmBut]CdMe with thiobenzoic acid. The molecular structure of [TmBut]Cd[κ1-SC(O)Ph] has been determined by X-ray diffraction, and an interesting feature is that, in contrast to the carboxylate derivatives [TmBut]Cd(κ2-O2CR), the thiocarboxylate ligand binds in a κ1 manner via only the sulfur atom. PMID:25826184

  15. Antimicrobial activity of CdS and Ag2S quantum dots immobilized on poly(amidoamine) grafted carbon nanotubes.

    PubMed

    Neelgund, Gururaj M; Oki, Aderemi; Luo, Zhiping

    2012-12-01

    Herein we report the design of antimicrobial nanohybrids, f-MWCNTs-CdS and f-MWCNTs-Ag(2)S developed by covalent grafting of cationic hyperbranched dendritic polyamidoamine (PAMAM) onto multiwalled carbon nanotubes (MWCNTs) and successive deposition of CdS and Ag(2)S quantum dots (QDs). The CdS and Ag(2)S QDs were in situ deposited on PAMAM grafted MWCNTs instead of anchoring the pre-synthesized QDs. The fourth generation, amine terminated hyperbranched PAMAM was grafted on MWCNTs, which was achieved through repetitive reactions of Michael addition of methylmethacrylate to the surface amino groups and amidation of terminal ester groups with ethylenediamine. The covalent grafting of PAMAM onto MWCNTs and the consecutive conjugation of CdS and Ag(2)S QDs were characterized using Fourier transform infrared spectroscopy, elemental analysis, powder X-ray diffraction, Raman spectroscopy, transmission electron microscopy and energy dispersive spectroscopy. The antibacterial activity of f-MWCNTs-CdS and f-MWCNTs-Ag(2)S nanohybrids was evaluated against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus and the results were compared with the activity of carboxylated MWCNTs, PAMAM grafted MWCNTs, PAMAM dendrimer, and CdS and Ag(2)S QDs. It was found that the germicidal action of MWCNTs was enhanced by grafting of PAMAM, which was further improved with immobilization of CdS and Ag(2)S QDs.

  16. Tunable Visible Emission of Ag-Doped CdZnS Alloy Quantum Dots.

    PubMed

    Sethi, Ruchi; Kumar, Lokendra; Sharma, Prashant K; Pandey, Ac

    2009-10-13

    Highly luminescent Ag-ion-doped Cd1-xZnxS (0 ≤ x ≤ 1) alloy nanocrystals were successfully synthesized by a novel wet chemical precipitation method. Influence of dopant concentration and the Zn/Cd stoichiometric variations in doped alloy nanocrystals have been investigated. The samples were characterized by X-ray diffraction (XRD) and high resolution transmission electron microscope (HRTEM) to investigate the size and structure of the as prepared nanocrystals. A shift in LO phonon modes from micro-Raman investigations and the elemental analysis from the energy dispersive X-ray analysis (EDAX) confirms the stoichiometry of the final product. The average crystallite size was found increasing from 1.0 to 1.4 nm with gradual increase in Ag doping. It was observed that photoluminescence (PL) intensity corresponding to Ag impurity (570 nm), relative to the other two bands 480 and 520 nm that originates due to native defects, enhanced and showed slight red shift with increasing silver doping. In addition, decrease in the band gap energy of the doped nanocrystals indicates that the introduction of dopant ion in the host material influence the particle size of the nanocrystals. The composition dependent bandgap engineering in CdZnS:Ag was achieved to attain the deliberate color tunability and demonstrated successfully, which are potentially important for white light generation.

  17. Tunable Visible Emission of Ag-Doped CdZnS Alloy Quantum Dots

    PubMed Central

    2010-01-01

    Highly luminescent Ag-ion-doped Cd1−xZnxS (0 ≤ x ≤ 1) alloy nanocrystals were successfully synthesized by a novel wet chemical precipitation method. Influence of dopant concentration and the Zn/Cd stoichiometric variations in doped alloy nanocrystals have been investigated. The samples were characterized by X-ray diffraction (XRD) and high resolution transmission electron microscope (HRTEM) to investigate the size and structure of the as prepared nanocrystals. A shift in LO phonon modes from micro-Raman investigations and the elemental analysis from the energy dispersive X-ray analysis (EDAX) confirms the stoichiometry of the final product. The average crystallite size was found increasing from 1.0 to 1.4 nm with gradual increase in Ag doping. It was observed that photoluminescence (PL) intensity corresponding to Ag impurity (570 nm), relative to the other two bands 480 and 520 nm that originates due to native defects, enhanced and showed slight red shift with increasing silver doping. In addition, decrease in the band gap energy of the doped nanocrystals indicates that the introduction of dopant ion in the host material influence the particle size of the nanocrystals. The composition dependent bandgap engineering in CdZnS:Ag was achieved to attain the deliberate color tunability and demonstrated successfully, which are potentially important for white light generation. PMID:20652135

  18. Tunable Visible Emission of Ag-Doped CdZnS Alloy Quantum Dots

    NASA Astrophysics Data System (ADS)

    Sethi, Ruchi; Kumar, Lokendra; Sharma, Prashant K.; Pandey, A. C.

    2010-01-01

    Highly luminescent Ag-ion-doped Cd1-xZnxS (0 ≤ x ≤ 1) alloy nanocrystals were successfully synthesized by a novel wet chemical precipitation method. Influence of dopant concentration and the Zn/Cd stoichiometric variations in doped alloy nanocrystals have been investigated. The samples were characterized by X-ray diffraction (XRD) and high resolution transmission electron microscope (HRTEM) to investigate the size and structure of the as prepared nanocrystals. A shift in LO phonon modes from micro-Raman investigations and the elemental analysis from the energy dispersive X-ray analysis (EDAX) confirms the stoichiometry of the final product. The average crystallite size was found increasing from 1.0 to 1.4 nm with gradual increase in Ag doping. It was observed that photoluminescence (PL) intensity corresponding to Ag impurity (570 nm), relative to the other two bands 480 and 520 nm that originates due to native defects, enhanced and showed slight red shift with increasing silver doping. In addition, decrease in the band gap energy of the doped nanocrystals indicates that the introduction of dopant ion in the host material influence the particle size of the nanocrystals. The composition dependent bandgap engineering in CdZnS:Ag was achieved to attain the deliberate color tunability and demonstrated successfully, which are potentially important for white light generation.

  19. Synthesis, crystal structure and optical properties of two new layered cadmium iodates: Cd(IO{sub 3})X (X=Cl, OH)

    SciTech Connect

    Yang, Bing-Ping Mao, Jiang-Gao

    2014-11-15

    Systematic explorations of new compounds in the cadmium iodate system by hydrothermal reactions led to two layered iodates, namely, Cd(IO{sub 3})X (X=Cl, OH). Cd(IO{sub 3})Cl crystallizes in the orthorhombic space group Cmca (No. 64) whereas Cd(IO{sub 3})(OH) crystallizes in the orthorhombic space group Pnma (No. 62). Cd(IO{sub 3})Cl displays a unique double layered structure composed of {sup 1}{sub ∞}[Cd−O{sub 3}Cl]{sub n} chains. Cadmium octahedrons form a 1D chain along the a-axis through edge sharing, and such chains are further interconnected via IO{sub 3} groups to form a special double layer on (020) plane. Cd(IO{sub 3})(OH) also exhibits a layered structure that is composed of cadmium cations, IO{sub 3} groups and hydroxyl ions. Within a layer, chains of CdO{sub 6} edge-shared octahedra are observed along the b-axis. And these chains are connected by IO{sub 3} groups into a layer parallel to the bc plane. Spectroscopic characterizations, elemental analysis, and thermogravimetric analysis for the reported two compounds are also presented. - Graphical abstract: Two new layered cadmium iodates Cd(IO{sub 3})X (X=Cl, OH) are reported. Cd(IO{sub 3})Cl features a unique double layered structure whereas Cd(IO{sub 3})(OH) displays an ordinary layered structure. - Highlights: • Two new layered cadmium iodates Cd(IO{sub 3})X (X=Cl, OH) are reported. • Cd(IO{sub 3})Cl features a unique double layered structure. • Cd(IO{sub 3})(OH) displays an ordinary layered structure. • The spectroscopic and thermal properties have been studied in detail.

  20. Determining the boundaries of second-type phase transitions in Ag-Mg-Cd alloys by means of diffusion couples

    NASA Astrophysics Data System (ADS)

    Kalmykov, K. B.; Dmitrieva, N. E.; Dunaev, S. F.

    2017-02-01

    The interaction between elements in the transition zones of diffusion couples Mg + AgCd-alloy are studied. Isothermal sections of the Ag-Mg-Cd ternary system at 573 K are constructed. The existence of a Heusler phase based on H-Ag2MgCd compound is found in the field of the solid β'-solution. It is shown that the interdiffusion of components prevents the formation of ordered phases in the transition zones of bimetals, allowing us to determine the boundaries of second-type phase transitions in solid solutions.

  1. ZnO/Ag/CdO nanocomposite for visible light-induced photocatalytic degradation of industrial textile effluents.

    PubMed

    Saravanan, R; Mansoob Khan, M; Gupta, Vinod Kumar; Mosquera, E; Gracia, F; Narayanan, V; Stephen, A

    2015-08-15

    A ternary ZnO/Ag/CdO nanocomposite was synthesized using thermal decomposition method. The resulting nanocomposite was characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, UV-Vis spectroscopy, and X-ray photoelectron spectroscopy. The ZnO/Ag/CdO nanocomposite exhibited enhanced photocatalytic activity under visible light irradiation for the degradation of methyl orange and methylene blue compared with binary ZnO/Ag and ZnO/CdO nanocomposites. The ZnO/Ag/CdO nanocomposite was also used for the degradation of the industrial textile effluent (real sample analysis) and degraded more than 90% in 210 min under visible light irradiation. The small size, high surface area and synergistic effect in the ZnO/Ag/CdO nanocomposite is responsible for high photocatalytic activity. These results also showed that the Ag nanoparticles induced visible light activity and facilitated efficient charge separation in the ZnO/Ag/CdO nanocomposite, thereby improving the photocatalytic performance.

  2. Phase Transition and Second Harmonic Generation in Thiophosphates Ag2Cd(P2S6) and AgCd3(PS4)S2 Containing Two Second-Order Jahn-Teller Distorted Cations.

    PubMed

    Fan, Yu-Hang; Jiang, Xiao-Ming; Liu, Bin-Wen; Li, Shu-Fang; Guo, Wei-Huan; Zeng, Hui-Yi; Guo, Guo-Cong; Huang, Jin-Shun

    2017-01-03

    Two new phases in the Ag-Cd-P-S system containing two second-order Jahn-Teller (SOJT) distorted d(10) cations (Cd(2+) and Ag(+)), namely, Ag2Cd(P2S6) (1) and AgCd3(PS4)S2 (2), are obtained via medium-temperature solid-state synthesis. Compound 1 exhibits a two-dimensional layered structure and undergoes a first-order structural phase transition at approximately 280 °C. This outcome can be ascribed to the significant mismatch in the expansion coefficients between Cd-S (Ag-S) and P-P (P-S) bonds evaluated through bond valence theory. The three-dimensional non-centrosymmetric (NCS) framework of 2 is constructed by two types of tetrahedral layers consisting of corner-shared CdS4, AgS4, and PS4 tetrahedra. Compound 2 exhibits second harmonic generation (SHG) intensity of 0.45 times that of commercial AgGaS2 (AGS) at a laser irradiation of 1.85 μm and an optical band gap of 2.56 eV, and no intrinsic vibrational absorption of chemical bonds is observed in the range of 2.5-18.2 μm. Both phase transition in 1 and SHG properties in 2 are closely related to the SOJT distorted d(10) cations and diverse phosphorus-sulfur polyanions (PaSb)(n-), which together can easily result in NCS distorted structures and interesting properties.

  3. Cadmium (Cd) Localization in Tissues of Cotton (Gossypium hirsutum L.), and Its Phytoremediation Potential for Cd-Contaminated Soils.

    PubMed

    Chen, Zhifan; Zhao, Ye; Fan, Lidong; Xing, Liteng; Yang, Yujie

    2015-12-01

    Phytoremediation using economically valuable, large biomass, non-edible plants is a promising method for metal-contaminated soils. This study investigated cotton's tolerance for Cd and remediation potential through analyzing Cd bioaccumulation and localization in plant organs under different soil Cd levels. Results showed cotton presents good tolerance when soil Cd concentration ≤20.26 mg kg(-1). Cotton had good Cd accumulation ability under low soil Cd levels (<1.26 mg kg(-1)), with a TF value (the ratio of Cd concentration in stem to root) above 1. Energy dispersive X-ray microanalysis indicated cotton leaf transpiration played a key role in extracting soil Cd, while roots and stems were the main compartments of Cd storage. Cd complexation to other organic constituents in root and stem cell sap could be a primary detoxifying strategy. Therefore, cotton is a potential candidate for phytoremediation of Cd-contaminated soils.

  4. Calculation of the structural parameters of small cadmium selenide clusters, (CdSe)n, n = 1,2,3

    NASA Astrophysics Data System (ADS)

    Alselawe, A. I. A.; Gopir, G.; Anas, M. M.

    2016-11-01

    The structural parameters of small cadmium selenide clusters (CdSe)n, for n=1,2, and 3 were studied. The calculations were performed using the pseudopotential and planewave basis sets, within the density functional theory. These parameters for geometry optimization can be used as elementary information for further investigations. The total energy calculations for the three linear structures of (CdSe)2 showed that these isomers are close in their stability. The rhombus structure (CdSe)2 planar is more stable isomer. The bond distances for the different structures show that the distances decrease with increasing the atoms in the structure. The calculated bond angles were close to other relevant studies.

  5. Cadmium uptake and translocation in tumbleweed (Salsola kali), a potential Cd-hyperaccumulator desert plant species: ICP/OES and XAS studies.

    PubMed

    de la Rosa, Guadalupe; Peralta-Videa, Jose R; Montes, Milka; Parsons, Jason G; Cano-Aguilera, Irene; Gardea-Torresdey, Jorge L

    2004-06-01

    Cadmium is a heavy metal, which, even at low concentrations, can be highly toxic to the growth and development of both plants and animals. Plant species vary extensively in their tolerance to excess cadmium in a growth medium and very few cadmium-tolerant species have been identified. In this study, tumbleweed plants (Salsola kali) grown in an agar-based medium with 20 mgl(-1) of Cd(II) did not show phytotoxicity, and their roots had the most biomass (4.5 mg) (P < 0.05) compared to the control plants (2.7 mg) as well as other treated plants. These plants accumulated 2696, 2075, and 2016 mg Cd kg(-1) of dry roots, stems, and leaves, respectively. The results suggest that there is no restricted cadmium movement in tumbleweed plants. In addition, the amount of Cd found in the dry leaf tissue suggests that tumbleweed could be considered as potential cadmium hyperaccumulating species. X-ray absorption spectroscopy studies demonstrated that in roots, cadmium was bound to oxygen while in stems and leaves, the metal was attached to oxygen and sulfur groups. This might imply that some small organic acids are responsible for Cd transport from roots to stems and leaves. In addition, it might be possible that the plant synthesizes phytochelatins in the stems, later coordinating the absorbed cadmium for transport and storage in cell structures. Thus, it is possible that in the leaves, Cd either exists as a Cd-phytochelatin complex or bound to cell wall structures. Current studies are being performed in order to elucidate the proposed hypothesis.

  6. Raman studies on Ag-ion doped CdZnS luminescent alloy quantum dots

    NASA Astrophysics Data System (ADS)

    Sethi, Ruchi; Sharma, Prashant K.; Pandey, A. C.; Kumar, Lokendra

    2010-07-01

    Un-doped and Ag-ion doped CdZnS alloy nanocrystals were synthesized using methaacrylic acid (MAA) as a capping agent. A continuous higher frequency shift in optical phonon modes was observed in the Raman spectra of the samples with increasing Zn composition demonstrating a typical 'one-mode' type behavior of the alloy material. Furthermore, the influence of MAA concentration on the optical and vibrational properties was also investigated. Transmission electron micrograph (TEM) of the samples shows that the CdZnS nanocrystals were embedded in the matrix of MAA. In addition, tremendous attention was paid towards the power induced Raman shift in the alloy nanocrystals.

  7. Ion-exchange synthesis and improved photovoltaic performance of CdS/Ag2S heterostructures for inorganic-organic hybrid solar cells

    NASA Astrophysics Data System (ADS)

    Xu, Xiaoyun; Wang, Xiong; Zhang, Yange; Li, Pinjiang

    2016-11-01

    A facile ultrasound-assisted ion exchange route was developed for the synthesis of CdS/Ag2S heterojunctions by ion exchange between the nanostructured CdS film and [Ag(NH3)2]+ under ultrasonication. The CdS/Ag2S heterojunction film was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis DRS spectroscopy, photoelectrochemical measurements, and the transient photovoltage (TPV) technique. CdSsbnd Ag2S heterojunctions exhibit a dense morphology, enhanced visible light absorption and stronger photocurrent response than the pure CdS films. Poly(3-hexylthiophene) (P3HT) was then spin coated into the CdS/Ag2S framework. Hybrid solar cells constructed with FTO/CdS/Ag2S/P3HT/Au display relatively higher power conversion efficiency than FTO/CdS/P3HT/Au.

  8. [Determination of Ag, Cu, Zn and Cd in silver brazing filler metals by ICP-AES].

    PubMed

    Yang, X

    1997-06-01

    A method of simultaneous and direct determination for Ag, Cu, Zn and Cd in silver brazing filler metals by ICP-AES is reported. The spectral interferences and effect of acidity have been investigated. Working conditions were optimized. The method has been applied to the analysis of silver brazing filler metals with RSD of 4-7% and recovery of 94-105%. This method was accurate, simple and rapid.

  9. The visible light photocatalytic activity enhancement of cotton cellulose nanofibers/In2S3/Ag-CdS nanocomposites

    NASA Astrophysics Data System (ADS)

    Pan, Jiaqi; Li, Jing; Zhang, Xiufang; Zheng, Yingying; Cui, Can; Zhu, Zhiyan; Li, Chaorong

    2016-07-01

    Cotton cellulose nanofibers (CCNFs)/In2S3/Ag-CdS nanocomposites were prepared by a typical technical route which combined electrospinning and a chemical method. The results showed that the CCNFs/In2S3/Ag-CdS nanocomposites had a remarkable visible light photocatalytic property and cycling stability, which displayed a significant enhancement compared with that of pure In2S3. Through analysis, this enhancement could be mainly attributed to the multilevel structure of the composites.

  10. Liver Toxicity of Cadmium Telluride Quantum Dots (CdTe QDs) Due to Oxidative Stress in Vitro and in Vivo

    PubMed Central

    Zhang, Ting; Hu, Yuanyuan; Tang, Meng; Kong, Lu; Ying, Jiali; Wu, Tianshu; Xue, Yuying; Pu, Yuepu

    2015-01-01

    With the applications of quantum dots (QDs) expanding, many studies have described the potential adverse effects of QDs, yet little attention has been paid to potential toxicity of QDs in the liver. The aim of this study was to investigate the effects of cadmium telluride (CdTe) QDs in mice and murine hepatoma cells alpha mouse liver 12 (AML 12). CdTe QDs administration significantly increased the level of lipid peroxides marker malondialdehyde (MDA) in the livers of treated mice. Furthermore, CdTe QDs caused cytotoxicity in AML 12 cells in a dose- and time-dependent manner, which was likely mediated through the generation of reactive oxygen species (ROS) and the induction of apoptosis. An increase in ROS generation with a concomitant increase in the gene expression of the tumor suppressor gene p53, the pro-apoptotic gene Bcl-2 and a decrease in the anti-apoptosis gene Bax, suggested that a mitochondria mediated pathway was involved in CdTe QDs’ induced apoptosis. Finally, we showed that NF-E2-related factor 2 (Nrf2) deficiency blocked induced oxidative stress to protect cells from injury induced by CdTe QDs. These findings provide insights into the regulatory mechanisms involved in the activation of Nrf2 signaling that confers protection against CdTe QDs-induced apoptosis in hepatocytes. PMID:26404244

  11. Transcriptomic changes during maize roots development responsive to Cadmium (Cd) pollution using comparative RNAseq-based approach.

    PubMed

    Peng, Hua; He, Xiujing; Gao, Jian; Ma, Haixia; Zhang, Zhiming; Shen, Yaou; Pan, Guangtang; Lin, Haijian

    2015-09-04

    The heavy metal cadmium (Cd), acts as a widespread environmental contaminant, which has shown to adversely affect human health, food safety and ecosystem safety in recent years. However, research on how plant respond to various kinds of heavy metal stress is scarcely reported, especially for understanding of complex molecular regulatory mechanisms and elucidating the gene networks of plant respond to Cd stress. Here, transcriptomic changes during Mo17 and B73 seedlings development responsive to Cd pollution were investigated and comparative RNAseq-based approach in both genotypes were performed. 115 differential expression genes (DEGs) with significant alteration in expression were found co-modulated in both genotypes during the maize seedling development; of those, most of DGEs were found comprised of stress and defense responses proteins, transporters, as well as transcription factors, such as thaumatin-like protein, ZmOPR2 and ZmOPR5. More interestingly, genotype-specific transcriptional factors changes induced by Cd stress were found contributed to the regulatory mechanism of Cd sensitivity in both different genotypes. Moreover, 12 co-expression modules associated with specific biological processes or pathways (M1 to M12) were identified by consensus co-expression network. These results will expand our understanding of complex molecular mechanism of response and defense to Cd exposure in maize seedling roots.

  12. Enhanced selective photocatalytic CO2 reduction into CO over Ag/CdS nanocomposites under visible light

    NASA Astrophysics Data System (ADS)

    Zhu, Zezhou; Qin, Jiani; Jiang, Min; Ding, Zhengxin; Hou, Yidong

    2017-01-01

    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 CO2 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 CO2-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 CO2 reduction, which is probably responsible for the enhanced activity and selectivity of CO2 to CO over Ag/CdS. The possible mechanism of CO2 photoreduction over Ag/CdS was proposed in view of the abovementioned analysis.

  13. Synthesis and characterization of AgI nanoparticles in β-CD/PAN nanofibers by electrospinning method

    NASA Astrophysics Data System (ADS)

    Liang, Haiou; Li, Chunping; Bai, Jie; Zhang, Lijuan; Guo, Liping; Huang, Yarong

    2013-04-01

    AgI nanoparticles/β-cyclodextrin (β-CD)/polyacrylonitrile (PAN) composite nanofibers film were prepared via a new route which combined electrospinning technology with the reaction of solid-liquid process. In this article, AgI nanoparticles were successfully prepared in β-CD/PAN nanofibers which contained different concentration β-CD by the new route. Firstly, the AgNO3-β-CD/PAN nanofibers were obtained via electrospinning method, then put the nanofibers into the solution of potassium iodide to prepare AgI-β-CD/PAN nanofibers. The morphology and structure of the composite nanofibers and nanoparticles have been investigated by scanning electron microscopy (SEM) and transmission electro microscopy (TEM). The existence of the AgI nanoparticles was proved by X-ray photoelectron spectroscopy (XPS) and X-ray diffractometer (XRD) patterns. The results of various characterizations indicated that the sample of AgI-β-CD (2 wt%)/PAN have the optimum morphology and structure.

  14. Effect of biochar on alleviation of cadmium toxicity in wheat (Triticum aestivum L.) grown on Cd-contaminated saline soil.

    PubMed

    Abbas, Tahir; Rizwan, Muhammad; Ali, Shafaqat; Adrees, Muhammad; Zia-Ur-Rehman, Muhammad; Qayyum, Muhammad Farooq; Ok, Yong Sik; Murtaza, Ghulam

    2017-04-10

    Soil degradation by salinity and accumulation of trace elements such as cadmium (Cd) in the soils are expected to become one of the most critical issues hindering sustainable production and feeding the increasing population. Biochar (BC) has been known to protect the plants against soil salinity and heavy metal stress. A soil culture study was performed to evaluate the effect of BC on wheat (Triticum aestivum L.) growth, biomass, and reducing Cd and sodium (Na) uptake grown in Cd-contaminated saline soil under ambient conditions. Soil salinity decreased the plant growth, biomass, grain yield, chlorophyll contents, and gas exchange parameters and caused oxidative stress in plants compared with Cd stress alone. Salt stress increased Cd and Na uptake and reduced the potassium (K) and zinc (Zn) uptake by plants. AB-DTPA-extractable Cd and soil electrical conductivity (ECe) increased under salt stress compared to the soil without NaCl stress. Biochar application improved the plant growth and reduced the Cd and Na uptake except in plants treated with higher BC and salt stress (5.0% BC + 50 mM NaCl). Biochar application reduced the oxidative stress in plants and modified the antioxidant enzyme activities, and reduced the bioavailable Cd under salt stress. The positive effects of BC under lower salt stress while the negative effects of BC under higher BC and salt levels indicated that BC doses should be used with great care in higher soil salinity levels simultaneously contaminated with Cd to avoid the negative effects of BC on growth and metal uptake.

  15. The Niujiaotang Cd-rich zinc deposit, Duyun, Guizhou province, southwest China: ore genesis and mechanisms of cadmium concentration

    NASA Astrophysics Data System (ADS)

    Ye, Lin; Cook, Nigel J.; Liu, Tiegeng; Ciobanu, Cristiana L.; Gao, Wei; Yang, Yulong

    2012-08-01

    The Niujiaotang zinc deposit in southeastern Guizhou, China, is a Mississippi Valley-type Zn deposit within Early Cambrian carbonate rocks. Sphalerite is enriched in cadmium (average 1.4 wt.% Cd), which occurs mostly as isomorphous impurities in the sphalerite lattice. Discrete cadmium minerals (greenockite and otavite) are rare and are found almost exclusively in the oxidation zone of the deposit, probably formed as secondary minerals during weathering-leaching processes. Geochemical data show that the sulfides are enriched in heavy sulfur, with δ34S ranging from +10.0‰ to +32.8‰ (mean +22.5‰). The consistent Pb isotopic compositions in different sulfide minerals are similar to that of Cambrian strata. The ore lead probably came from U- and Th-rich upper crustal rocks, such as the Lower Cambrian Wuxun Formation. The ore fluid is of low-temperature (101°C to 142°C) type, with a Na-Ca-Mg-Cl-dominant composition, and is interpreted as oil-field brine. The data indicate that the metals were mainly derived from the Early Cambrian strata (Qingxudong and Wuxun Formations), whereas sulfur is sourced from sulfate in Cambrian strata or oil-field brines of the Majiang petroleum paleoreservoir. The genetic model for the deposit invokes an Early Cambrian shallow-sea environment on the Yangtze Platform. Zinc and Cd in seawater were concentrated in abundant algae via unknown biological mechanisms, resulting in large amounts of Zn- and Cd-rich algal ooliths. During the Ordovician, concurrent with destruction of the Majiang petroleum paleoreservoir, oil-field brines migrated from the center of the basin to the margin leaching metals from the Cambrian strata. In the Niujiaotang area, preexisting Zn and Cd, particularly in the Qingxudong and Wuxun Formation, were further mobilized by hot brines rising along the Zaolou fault system, forming stratiform and generally conformable Zn-Cd orebodies in reactive carbonate lithologies.

  16. Effect of Ag doping on the electrical properties of thermally deposited CdS-La2O3 TFTs

    NASA Astrophysics Data System (ADS)

    Gogoi, Paragjyoti; Saikia, Rajib

    2012-06-01

    In this article, we have reported the fabrication of CdS thin film transistors (TFTs) doped with Ag by thermal evaporation technique on chemically cleaned glass substrates using multiple pumps down process. High-k rare earth oxide La2O3 is used as gate dielectric in CdS TFTs. Some important electrical parameters have been evaluated using Weimer's model. The electrical parameters are compared with the parameters of undoped CdS TFTs. The Ag-doped CdS TFTs exhibit a high mobility of 6.1 cm2 V-1 s-1 than that of the undoped CdS TFTs, mobility of which is found as 6.25 × 10-2 cm2 V-1 s-1. The TFTs also exhibit low threshold voltage. Both Ag-doped and undoped TFTs are characterised using Levinson et al. model.

  17. The influence of long-term fertilization on cadmium (Cd) accumulation in soil and its uptake by crops.

    PubMed

    Wang, Qingyun; Zhang, Jiabao; Zhao, Bingzi; Xin, Xiuli; Zhang, Congzhi; Zhang, Hailin

    2014-09-01

    Continuous application of organic and inorganic fertilizers can affect soil and food quality with respect to heavy metal concentrations. The risk of cadmium (Cd) contamination in a long-term (over 20 years) experimental field in North China with an annual crop rotation of winter wheat and summer maize was investigated. The long-term experiment had a complete randomized block design with seven fertilizer treatments and four replications. The seven fertilizer treatments were (1) organic compost (OM), (2) half organic compost plus half chemical fertilizer (OM + NPK), (3) NPK fertilizer (NPK), (4-6) chemical fertilizers without one of the major nutrients (NP, PK, and NK), and (7) an unamended control (CK). Soil samples from 0 to 20 cm were collected in 1989, 1999, and 2009 to characterize Cd and other soil properties. During the past 20 years, various extents of Cd accumulation were observed in the soil, and the accumulation was mainly affected by atmospheric dry and wet deposition and fertilization. In 2009, the average Cd concentration in the soil was 148 ± 15 μg kg(-1) and decreased in the order of NPK ≈ OM + NKP ≈ PK > NP ≈ NK > OM ≈ CK. Sequential extraction of Cd showed that the acid-soluble fraction (F1, 32 ± 7 %) and the residual fraction (F4, 31 ± 5 %) were the dominant fractions of Cd in the soil, followed by the reducible fraction (F2, 22 ± 5 %) and oxidizable fraction (F3, 15 ± 6 %). The acid-soluble Cd fraction in the soil and Cd accumulation in the crops increased with soil plant available K. Fraction F3 was increased by soil organic C (SOC) and crop yields, but SOC reduced the uptake of soil Cd by crops. The long-term P fertilization resulted in more Cd buildup in the soil than other treatments, but the uptake of Cd by crops was inhibited by the precipitation of Cd with phosphate in the soil. Although soil Cd was slightly increased over the 20 years of intensive crop production, both soil and grain/kernel Cd concentrations were still

  18. Isolation of a selenite-reducing and cadmium-resistant bacterium Pseudomonas sp. strain RB for microbial synthesis of CdSe nanoparticles.

    PubMed

    Ayano, Hiroyuki; Miyake, Masaki; Terasawa, Kanako; Kuroda, Masashi; Soda, Satoshi; Sakaguchi, Toshifumi; Ike, Michihiko

    2014-05-01

    Bacteria capable of synthesizing CdSe from selenite and cadmium ion were enriched from a soil sample. After repeated transfer of the soil-derived bacterial cultures to a new medium containing selenite and cadmium ion 42 times (during 360 days), an enrichment culture that can simultaneously remove selenite and cadmium ion (1 mM each) from the liquid phase was obtained. The culture's color became reddish-brown, indicating CdSe nanoparticle production, as confirmed by energy-dispersive x-ray spectra (EDS). As a result of isolation operations, the bacterium that was the most responsible for synthesizing CdSe, named Pseudomonas sp. RB, was obtained. Transmission electron microscopy and EDS revealed that this strain accumulated nanoparticles (10-20 nm) consisting of selenium and cadmium inside and on the cells when cultivated in the same medium for the enrichment culture. This report is the first describing isolation of a selenite-reducing and cadmium-resistant bacterium. It is useful for CdSe nanoparticle synthesis in the simple one-vessel operation.

  19. Photoelectric properties of ITO/CdS/chlorophyll a/Ag heterojunction solar cells

    SciTech Connect

    Segui, J.; Hotchandani, S.; Baddou, D.; Leblanc, R.M. )

    1991-10-31

    The heterojunction ITO/CdS/Chl a/Ag (Chl a = chlorophyll a) solar cells have been prepared by sequential electrodeposition of CdS and Chl a onto conductive indium-tin oxide (ITO) electrode followed by vacuum deposition of Ag, and their photovoltaic studies have been carried out. The dark J-V and photovoltaic characteristics, especially the action spectra, suggest the presence of a barrier at CdS/CFhl a interface. Various photovoltaic parameters of the cells obtained for the incident light power of 20 {mu}W/Cm{sup 2} at 740 nm, the maximum of Chl a absorption in red region, are as follows: J{sub SC} {approx equal} 150-200 nA/cm{sup 2}, V{sub OC} {approx} 0.35-0.40 V, ff = 0.26, and {eta} (%) = 0.17. The measurements performed at three wavelengths, namely, 740, 680, and 560 nm, indicate that the cells (illuminated through CdS electrode) perform better for weakly absorbed light at 560 nm. The results further show that the use of CdS instead of Al as rectifying electrode has definitely led to an improvement in the performance of CdS/Chl a over Al/Chl a cells in terms of the decreased internal resistances, decreased dark current and voltage, increased fill factors, and increased power conversion efficiencies. This has been attributed to the elimination of insulating layer of Al{sub 2}O{sub 3} existing at Al/Chl a interface.

  20. Transcriptomic changes during maize roots development responsive to Cadmium (Cd) pollution using comparative RNAseq-based approach

    SciTech Connect

    Peng, Hua; He, Xiujing; Gao, Jian; Ma, Haixia; Zhang, Zhiming; Shen, Yaou; Pan, Guangtang; Lin, Haijian

    2015-09-04

    The heavy metal cadmium (Cd), acts as a widespread environmental contaminant, which has shown to adversely affect human health, food safety and ecosystem safety in recent years. However, research on how plant respond to various kinds of heavy metal stress is scarcely reported, especially for understanding of complex molecular regulatory mechanisms and elucidating the gene networks of plant respond to Cd stress. Here, transcriptomic changes during Mo17 and B73 seedlings development responsive to Cd pollution were investigated and comparative RNAseq-based approach in both genotypes were performed. 115 differential expression genes (DEGs) with significant alteration in expression were found co-modulated in both genotypes during the maize seedling development; of those, most of DGEs were found comprised of stress and defense responses proteins, transporters, as well as transcription factors, such as thaumatin-like protein, ZmOPR2 and ZmOPR5. More interestingly, genotype-specific transcriptional factors changes induced by Cd stress were found contributed to the regulatory mechanism of Cd sensitivity in both different genotypes. Moreover, 12 co-expression modules associated with specific biological processes or pathways (M1 to M12) were identified by consensus co-expression network. These results will expand our understanding of complex molecular mechanism of response and defense to Cd exposure in maize seedling roots. - Highlights: • Transcriptomic changes responsive to Cd pollution using comparative RNAseq-based approach. • 115 differential expression genes (DEGs) were found co-modulated in both genotypes. • Most of DGEs belong to stress and defense responses proteins, transporters, transcription factors. • 12 co-expression modules associated with specific biological processes or pathways. • Genotype-specific transcriptional factors changes induced by Cd stress were found.

  1. Facile in situ synthesis of hydrophilic RGO-CD-Ag supramolecular hybrid and its enhanced antibacterial properties.

    PubMed

    Li, Tie; Shen, Jianfeng; Li, Na; Ye, Mingxin

    2014-06-01

    In this study, a novel hydrophilic RGO-CD-Ag hybrid with the supramolecular β-cyclodextrin (CD) as a conjugation interface was fabricated successfully by a facile in situ synthesis process. The results of several characterizations confirmed that the in situ reaction provided a straightforward approach to deposit the CD wrapped Ag nanoparticles onto the CD chemical functionalized RGO sheets through the head-to-head H-bond interactions between the linker CD molecules. Moreover, it was also found that the CD interface that existed indeed influences the structure and performances of RGO-CD-Ag nanocomposite. The analysis of the static contact angle revealed that the surface property of the hybrid could be transformed from hydrophobic to hydrophilic feature, which highly improved the aqueous dispersibility. And then, the bactericidal test of RGO-CD-Ag was demonstrated and clearly showed the strongest antibacterial activity against Gram-negative and Gram-positive bacteria among all samples. In short, this method may readily provide a new family of supramolecular based materials expected to find applications beyond the bactericidal field.

  2. Decorating CdTe QD-Embedded Mesoporous Silica Nanospheres with Ag NPs to Prevent Bacteria Invasion for Enhanced Anticounterfeit Applications.

    PubMed

    Gao, Yangyang; Dong, Qigeqi; Lan, Shi; Cai, Qian; Simalou, Oudjaniyobi; Zhang, Shiqi; Gao, Ge; Chokto, Harnoode; Dong, Alideertu

    2015-05-13

    Quantum dots (QDs) as potent candidates possess advantageous superiority in fluorescence imaging applications, but they are susceptible to the biological circumstances (e.g., bacterial environment), leading to fluorescence quenching or lose of fluorescent properties. In this work, CdTe QDs were embedded into mesoporous silica nanospheres (m-SiO2 NSs) for preventing QD agglomeration, and then CdTe QD-embedded m-SiO2 NSs (m-SiO2/CdTe NSs) were modified with Ag nanoparticles (Ag NPs) to prevent bacteria invasion for enhanced anticounterfeit applications. The m-SiO2 NSs, which serve as intermediate layers to combine CdTe QDs with Ag NPs, help us establish a highly fluorescent and long-term antibacterial system (i.e., m-SiO2/CdTe/Ag NSs). More importantly, CdTe QD-embedded m-SiO2 NSs showed fluorescence quenching when they encounter bacteria, which was avoided by attaching Ag NPs outside. Ag NPs are superior to CdTe QDs for preventing bacteria invasion because of the structure (well-dispersed Ag NPs), size (small diameter), and surface charge (positive zeta potentials) of Ag NPs. The plausible antibacterial mechanisms of m-SiO2/CdTe/Ag NSs toward both Gram-positive and Gram-negative bacteria were established. As for potential applications, m-SiO2/CdTe/Ag NSs were developed as fluorescent anticounterfeiting ink for enhanced imaging applications.

  3. β-CD Dimer-immobilized Ag Assembly Embedded Silica Nanoparticles for Sensitive Detection of Polycyclic Aromatic Hydrocarbons

    NASA Astrophysics Data System (ADS)

    Hahm, Eunil; Jeong, Daham; Cha, Myeong Geun; Choi, Jae Min; Pham, Xuan-Hung; Kim, Hyung-Mo; Kim, Hwanhee; Lee, Yoon-Sik; Jeong, Dae Hong; Jung, Seunho; Jun, Bong-Hyun

    2016-05-01

    We designed a β-CD dimer on silver nanoparticles embedded with silica nanoparticles (Ag@SiO2 NPs) structure to detect polycyclic aromatic hydrocarbons (PAHs). Silica NPs were utilized as a template for embedding silver NPs to create hot spot structures and enhance the surface-enhanced Raman scattering (SERS) signal, and a thioether-bridged dimeric β-CD was immobilized on Ag NPs to capture PAHs. The assembled Ag NPs on silica NPs were confirmed by TEM and the presence of β-CD dimer on Ag@SiO2 was confirmed by UV-vis and attenuated total reflection-Fourier transform infrared spectroscopy. The β-CD dimer@Ag@SiO2 NPs were used as SERS substrate for detecting perylene, a PAH, directly and in a wide linearity range of 10‑7 M to 10‑2 M with a low detection limit of 10‑8 M. Also, the β-CD dimer@Ag@SiO2 NPs exhibited 1000-fold greater sensitivity than Ag@SiO2 NPs in terms of their perylene detection limit. Furthermore, we demonstrated the possibility of detecting various PAH compounds using the β-CD dimer@Ag@SiO2 NPs as a multiplex detection tool. Various PAH compounds with the NPs exhibited their distinct SERS bands by the ratio of each PAHs. This approach of utilizing the assembled structure and the ligands to recognize target has potential for use in sensitive analytical sensors.

  4. β-CD Dimer-immobilized Ag Assembly Embedded Silica Nanoparticles for Sensitive Detection of Polycyclic Aromatic Hydrocarbons

    PubMed Central

    Hahm, Eunil; Jeong, Daham; Cha, Myeong Geun; Choi, Jae Min; Pham, Xuan-Hung; Kim, Hyung-Mo; Kim, Hwanhee; Lee, Yoon-Sik; Jeong, Dae Hong; Jung, Seunho; Jun, Bong-Hyun

    2016-01-01

    We designed a β-CD dimer on silver nanoparticles embedded with silica nanoparticles (Ag@SiO2 NPs) structure to detect polycyclic aromatic hydrocarbons (PAHs). Silica NPs were utilized as a template for embedding silver NPs to create hot spot structures and enhance the surface-enhanced Raman scattering (SERS) signal, and a thioether-bridged dimeric β-CD was immobilized on Ag NPs to capture PAHs. The assembled Ag NPs on silica NPs were confirmed by TEM and the presence of β-CD dimer on Ag@SiO2 was confirmed by UV-vis and attenuated total reflection-Fourier transform infrared spectroscopy. The β-CD dimer@Ag@SiO2 NPs were used as SERS substrate for detecting perylene, a PAH, directly and in a wide linearity range of 10−7 M to 10−2 M with a low detection limit of 10−8 M. Also, the β-CD dimer@Ag@SiO2 NPs exhibited 1000-fold greater sensitivity than Ag@SiO2 NPs in terms of their perylene detection limit. Furthermore, we demonstrated the possibility of detecting various PAH compounds using the β-CD dimer@Ag@SiO2 NPs as a multiplex detection tool. Various PAH compounds with the NPs exhibited their distinct SERS bands by the ratio of each PAHs. This approach of utilizing the assembled structure and the ligands to recognize target has potential for use in sensitive analytical sensors. PMID:27184729

  5. Metal arsonate polymers of Cd, Zn, Ag and Pb supported by 4-aminophenylarsonic acid

    NASA Astrophysics Data System (ADS)

    Lesikar-Parrish, Leslie A.; Neilson, Robert H.; Richards, Anne F.

    2013-02-01

    The coordination preferences of 4-aminophenylarsonic acid, 4-NH2C6H4AsO3H2, (p-arsanilic acid) with CdCl2·2.5H2O, ZnCl2, Ag(SO3CF3) and Pb(NO3)2 have been investigated affording five new metal arsonate polymers. The reaction between 4-aminophenylarsonic acid and CdCl2·2.5H2O resulted in a one-dimensional polymer, [{Cd(4-NH3C6H4AsO3H)(Cl)2}(H2O)2]n, 1, in which the polymeric chain is propagated by bridging chlorides. Exchange of CdCl2 for ZnCl2 afforded [{Zn2(4-NH3C6H4AsO3)(Cl)2}(H2O)2(Cl)]n, 2, featuring interlinked 6- and 8-membered [Zn-O-As] ring systems. The reaction of Ag(SO3CF3) with 4-aminophenylarsonic acid, afforded polymeric 3, [Ag(4-NH2C6H4AsO3H)(4-NH2C6H4AsO3H2)]n where coordination of the amino group to the silver center is observed and [{Ag2(4-NH3C6H4AsO3H)(4-NH3C6H4AsO3)(μ2-SO3CF3)2}(SO3CF3)2]n, 4. By comparison, the reaction of p-arsanilic acid with Pb(NO3)2 yielded a polymeric chain [Pb(4-NH3C6H4AsO3H)(NO3)2]n, 5 of similar topology to 1. The structures of 1-5 have been indiscriminately characterized by single crystal X-ray diffraction and their composition supported by relevant spectroscopic techniques. A comparison of the structural features of these polymers is used to determine the coordination preference of the ligand and factors influencing structural motifs, for example, the role of the anion.

  6. Cadmium sulfide nanowires for the window semiconductor layer in thin film CdS-CdTe solar cells.

    PubMed

    Liu, Piao; Singh, Vijay P; Jarro, Carlos A; Rajaputra, Suresh

    2011-04-08

    Thin film CdS/CdTe heterojunction device is a leading technology for the solar cells of the next generation. We report on two novel device configurations for these cells where the traditional CdS window layer is replaced by nanowires (NW) of CdS, embedded in an aluminum oxide matrix or free-standing. An estimated 26.8% improvement in power conversion efficiency over the traditional device structure is expected, primarily because of the enhanced spectral transmission of sunlight through the NW-CdS layer and a reduction in the junction area/optical area ratio. In initial experiments, nanostructured devices of the two designs were fabricated and a power conversion efficiency value of 6.5% was achieved.

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

    USGS Publications Warehouse

    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.

  8. Divergent tropism of HHV-6AGS and HHV-6BPL1 in T cells expressing different CD46 isoform patterns.

    PubMed

    Hansen, Aida S; Bundgaard, Bettina B; Biltoft, Mette; Rossen, Litten S; Höllsberg, Per

    2017-02-01

    CD46 is a receptor for HHV-6A, but its role as a receptor for HHV-6B is controversial. The significance of CD46 isoforms for HHV-6A and HHV-6B tropism is unknown. HHV-6AGS was able to initiate transcription of the viral genes U7 and U23 in the CD46(+)CD134(-) T-cell lines Peer, Jurkat, Molt3, and SupT1, whereas HHV-6BPL1 was only able to do so in Molt3 and SupT1, which expressed a CD46 isoform pattern different from Peer and Jurkat. The HHV-6BPL1-susceptible T-cell lines were characterized by low expression of the CD46 isoform BC2 and domination of isoforms containing the cytoplasmic tail, CYT-1. A HHV-6BPL1 susceptible cell line, Be13, changed over time its CD46 isoform pattern to resemble Peer and Jurkat and concomitantly lost its susceptibility to HHV-6BPL1 but not HHV-6AGS infection. We propose that isoforms of CD46 impact on HHV-6B infection and thereby in part explain the distinct tropism of HHV-6AGS and HHV-6BPL1.

  9. Zn/Cd ratios and cadmium isotope evidence for the classification of lead-zinc deposits

    PubMed Central

    Wen, Hanjie; Zhu, Chuanwei; Zhang, Yuxu; Cloquet, Christophe; Fan, Haifeng; Fu, Shaohong

    2016-01-01

    Lead-zinc deposits are often difficult to classify because clear criteria are lacking. In recent years, new tools, such as Cd and Zn isotopes, have been used to better understand the ore-formation processes and to classify Pb-Zn deposits. Herein, we investigate Cd concentrations, Cd isotope systematics and Zn/Cd ratios in sphalerite from nine Pb-Zn deposits divided into high-temperature systems (e.g., porphyry), low-temperature systems (e.g., Mississippi Valley type [MVT]) and exhalative systems (e.g., sedimentary exhalative [SEDEX]). Our results showed little evidence of fractionation in the high-temperature systems. In the low-temperature systems, Cd concentrations were the highest, but were also highly variable, a result consistent with the higher fractionation of Cd at low temperatures. The δ114/110Cd values in low-temperature systems were enriched in heavier isotopes (mean of 0.32 ± 0.31‰). Exhalative systems had the lowest Cd concentrations, with a mean δ114/110Cd value of 0.12 ± 0.50‰. We thus conclude that different ore-formation systems result in different characteristic Cd concentrations and fraction levels and that low-temperature processes lead to the most significant fractionation of Cd. Therefore, Cd distribution and isotopic studies can support better understanding of the geochemistry of ore-formation processes and the classification of Pb-Zn deposits. PMID:27121538

  10. Zn/Cd ratios and cadmium isotope evidence for the classification of lead-zinc deposits.

    PubMed

    Wen, Hanjie; Zhu, Chuanwei; Zhang, Yuxu; Cloquet, Christophe; Fan, Haifeng; Fu, Shaohong

    2016-04-28

    Lead-zinc deposits are often difficult to classify because clear criteria are lacking. In recent years, new tools, such as Cd and Zn isotopes, have been used to better understand the ore-formation processes and to classify Pb-Zn deposits. Herein, we investigate Cd concentrations, Cd isotope systematics and Zn/Cd ratios in sphalerite from nine Pb-Zn deposits divided into high-temperature systems (e.g., porphyry), low-temperature systems (e.g., Mississippi Valley type [MVT]) and exhalative systems (e.g., sedimentary exhalative [SEDEX]). Our results showed little evidence of fractionation in the high-temperature systems. In the low-temperature systems, Cd concentrations were the highest, but were also highly variable, a result consistent with the higher fractionation of Cd at low temperatures. The δ(114/110)Cd values in low-temperature systems were enriched in heavier isotopes (mean of 0.32 ± 0.31‰). Exhalative systems had the lowest Cd concentrations, with a mean δ(114/110)Cd value of 0.12 ± 0.50‰. We thus conclude that different ore-formation systems result in different characteristic Cd concentrations and fraction levels and that low-temperature processes lead to the most significant fractionation of Cd. Therefore, Cd distribution and isotopic studies can support better understanding of the geochemistry of ore-formation processes and the classification of Pb-Zn deposits.

  11. Zn/Cd ratios and cadmium isotope evidence for the classification of lead-zinc deposits

    NASA Astrophysics Data System (ADS)

    Wen, Hanjie; Zhu, Chuanwei; Zhang, Yuxu; Cloquet, Christophe; Fan, Haifeng; Fu, Shaohong

    2016-04-01

    Lead-zinc deposits are often difficult to classify because clear criteria are lacking. In recent years, new tools, such as Cd and Zn isotopes, have been used to better understand the ore-formation processes and to classify Pb-Zn deposits. Herein, we investigate Cd concentrations, Cd isotope systematics and Zn/Cd ratios in sphalerite from nine Pb-Zn deposits divided into high-temperature systems (e.g., porphyry), low-temperature systems (e.g., Mississippi Valley type [MVT]) and exhalative systems (e.g., sedimentary exhalative [SEDEX]). Our results showed little evidence of fractionation in the high-temperature systems. In the low-temperature systems, Cd concentrations were the highest, but were also highly variable, a result consistent with the higher fractionation of Cd at low temperatures. The δ114/110Cd values in low-temperature systems were enriched in heavier isotopes (mean of 0.32 ± 0.31‰). Exhalative systems had the lowest Cd concentrations, with a mean δ114/110Cd value of 0.12 ± 0.50‰. We thus conclude that different ore-formation systems result in different characteristic Cd concentrations and fraction levels and that low-temperature processes lead to the most significant fractionation of Cd. Therefore, Cd distribution and isotopic studies can support better understanding of the geochemistry of ore-formation processes and the classification of Pb-Zn deposits.

  12. Metal Cyanide Ions Mx(CN)y]+,- in the gas phase: M = Fe, Co, Ni, Zn, Cd, Hg, Fe + Ag, Co + Ag.

    PubMed

    Dance, Ian G; Dean, Philip A W; Fisher, Keith J; Harris, Hugh H

    2002-07-01

    The generation of metal cyanide ions in the gas phase by laser ablation of M(CN)(2) (M = Co, Ni, Zn, Cd, Hg), Fe(III)[Fe(III)(CN)(6)] x xH(2)O, Ag(3)[M(CN)(6)] (M = Fe, Co), and Ag(2)[Fe(CN)(5)(NO)] has been investigated using Fourier transform ion cyclotron resonance mass spectrometry. Irradiation of Zn(CN)(2) and Cd(CN)(2) produced extensive series of anions, [Zn(n)(CN)(2n+1)](-) (1 < or = n < or = 27) and [Cd(n)(CN)(2n+1)](-) (n = 1, 2, 8-27, and possibly 29, 30). Cations Hg(CN)(+) and [Hg(2)(CN)(x)](+) (x = 1-3), and anions [Hg(CN)(x)](-) (x = 2, 3), are produced from Hg(CN)(2). Irradiation of Fe(III)[Fe(III)(CN)(6)] x xH(2)O gives the anions [Fe(CN)(2)](-), [Fe(CN)(3)](-), [Fe(2)(CN)(3)](-), [Fe(2)(CN)(4)](-), and [Fe(2)(CN)(5)](-). When Ag(3)[Fe(CN)(6)] is ablated, [AgFe(CN)(4)](-) and [Ag(2)Fe(CN)(5)](-) are observed together with homoleptic anions of Fe and Ag. The additional heterometallic complexes [AgFe(2)(CN)(6)](-), [AgFe(3)(CN)(8)](-), [Ag(2)Fe(2)(CN)(7)](-), and [Ag(3)Fe(CN)(6)](-) are observed on ablation of Ag(2)[Fe(CN)(5)(NO)]. Homoleptic anions [Co(n)(CN)(n+1)](-) (n = 1-3), [Co(n)(CN)(n+2)](-) (n = 1-3), [Co(2)(CN)(4)](-), and [Co(3)(CN)(5)](-) are formed when anhydrous Co(CN)(2) is the target. Ablation of Ag(3)[Co(CN)(6)] yields cations [Ag(n)(CN)(n-1)](+) (n = 1-4) and [Ag(n)Co(CN)(n)](+) (n = 1, 2) and anions [Ag(n)(CN)(n+1)](-) (n = 1-3), [Co(n)(CN)(n-1)](-) (n = 1, 2), [Ag(n)Co(CN)(n+2)](-) (n = 1, 2), and [Ag(n)Co(CN)(n+3)](-) (n = 0-2). The Ni(I) species [Ni(n)(CN)(n-1)](+) (n = 1-4) and [Ni(n)(CN)(n+1)](-) (n = 1-3) are produced when anhydrous Ni(CN)(2) is irradiated. In all cases, CN(-) and polyatomic carbon nitride ions C(x)N(y)(-) are formed concurrently. On the basis of density functional calculations, probable structures are proposed for most of the newly observed species. General structural features are low coordination numbers, regular trigonal coordination stereochemistry for d(10) metals but distorted trigonal stereochemistry

  13. Availability of sediment-bound Cd, Co, and Ag to mussels

    SciTech Connect

    Gagnon, C.; Fisher, N.S.

    1995-12-31

    Ingested sediment is one potentially important source of metals for benthic organisms. The influence of physical and chemical properties of oxidized sediments on the bioavailability of metals to marine filter feeders is largely unknown. The authors examined the relative importance of specific sedimentary components that may exert control on the uptake of Cd, Co, and Ag in the mussel Mytilus edulis. Iron and manganese oxides, montmorillonite clay, silica, and natural sediment particles were triple labeled with the gamma emitters {sup 109}Cd, {sup 57}Co, and {sup 110m}Ag. Some particles were also coated with fulvic acid (FA) to simulate the influence of organic coating on metal bioavailability. Metals associated with FA-coated particles were generally absorbed by mussels to a greater extent than metals associated with uncoated particles. Desorption experiments with labeled particles at pH 5 were performed in parallel to simulate the behavior of food-bound metals in the acidic gut of bivalves. High correlations (r > 0.97) between the amount of desorbed metal under these conditions and the assimilation efficiency for metals from FA-coated particles were noted among coated particles but not uncoated particles (r < 0.6). These results suggest that the relation between metal partitioning to sediments and biological availability of the metal is not obvious, since the organic coatings and the acidic digestion process influence assimilation of sediment-bound metals.

  14. Biological interaction between transition metals (Ag, Cd and Hg), selenide/sulfide and selenoprotein P.

    PubMed

    Sasakura, C; Suzuki, K T

    1998-09-01

    The interaction between transition metals (Ag+, Cd2+ and Hg2+) and selenium (Se) in the bloodstream was studied in vitro by means of the HPLC--inductively coupled argon plasma-mass spectrometry (ICP MS) method. Transition metal ions and selenide (produced in vitro from selenite in the presence of glutathione) or sulfide (Na2S) formed a (metal-Se/S) complex, which then bound to a plasma protein, selenoprotein P (Sel P), to form a ternary complex, (metal-Se/S)-Sel P. The molar ratios of metals to Se were 1:1 for Hg/Se and Cd/Se, but either 1:1 or 2:1 for Ag/Se, depending on the ratio of their doses. The results indicate that the interaction between transition metals and Se occurs through the general mechanism, i.e., transition metal ions and selenide form the unit complex (metal-Se)n, and then the complex binds to selenoprotein P to form the ternary complex ¿(metal-Se)n¿m--seleno-protein P in the bloodstream.

  15. Transcriptome sequencing and differential gene expression analysis in Viola yedoensis Makino (Fam. Violaceae) responsive to cadmium (Cd) pollution

    SciTech Connect

    Gao, Jian; Luo, Mao; Zhu, Ye; He, Ying; Wang, Qin; Zhang, Chun

    2015-03-27

    Viola yedoensis Makino is an important Chinese traditional medicine plant adapted to cadmium (Cd) pollution regions. Illumina sequencing technology was used to sequence the transcriptome of V. yedoensis Makino. We sequenced Cd-treated (VIYCd) and untreated (VIYCK) samples of V. yedoensis, and obtained 100,410,834 and 83,587,676 high quality reads, respectively. After de novo assembly and quantitative assessment, 109,800 unigenes were finally generated with an average length of 661 bp. We then obtained functional annotations by aligning unigenes with public protein databases including NR, NT, SwissProt, KEGG and COG. In addition, 892 differentially expressed genes (DEGs) were investigated between the two libraries of untreated (VIYCK) and Cd-treated (VIYCd) plants. Moreover, 15 randomly selected DEGs were further validated with qRT-PCR and the results were highly accordant with the Solexa analysis. This study firstly generated a successful global analysis of the V. yedoensis transcriptome and it will provide for further studies on gene expression, genomics, and functional genomics in Violaceae. - Highlights: • A de novo assembly generated 109,800 unigenes and 5,4479 of them were annotated. • 31,285 could be classified into 26 COG categories. • 263 biosynthesis pathways were predicted and classified into five categories. • 892 DEGs were detected and 15 of them were validated by qRT-PCR.

  16. Transcriptome sequencing and differential gene expression analysis in Viola yedoensis Makino (Fam. Violaceae) responsive to cadmium (Cd) pollution.

    PubMed

    Gao, Jian; Luo, Mao; Zhu, Ye; He, Ying; Wang, Qin; Zhang, Chun

    2015-03-27

    Viola yedoensis Makino is an important Chinese traditional medicine plant adapted to cadmium (Cd) pollution regions. Illumina sequencing technology was used to sequence the transcriptome of V. yedoensis Makino. We sequenced Cd-treated (VIYCd) and untreated (VIYCK) samples of V. yedoensis, and obtained 100,410,834 and 83,587,676 high quality reads, respectively. After de novo assembly and quantitative assessment, 109,800 unigenes were finally generated with an average length of 661 bp. We then obtained functional annotations by aligning unigenes with public protein databases including NR, NT, SwissProt, KEGG and COG. In addition, 892 differentially expressed genes (DEGs) were investigated between the two libraries of untreated (VIYCK) and Cd-treated (VIYCd) plants. Moreover, 15 randomly selected DEGs were further validated with qRT-PCR and the results were highly accordant with the Solexa analysis. This study firstly generated a successful global analysis of the V. yedoensis transcriptome and it will provide for further studies on gene expression, genomics, and functional genomics in Violaceae.

  17. Subcellular cadmium distribution and antioxidant enzymatic activities in the leaves of two castor (Ricinus communis L.) cultivars exhibit differences in Cd accumulation.

    PubMed

    Zhang, Hanzhi; Guo, Qingjun; Yang, Junxing; Shen, Jianxiu; Chen, Tongbin; Zhu, Guangxu; Chen, Hui; Shao, Chunyan

    2015-10-01

    The aims of this study were: (1) the study of cadmium (Cd) accumulation and toxicity in different castor cultivars (Ricinus communis L.); (2) to investigate changes in antioxidant enzymatic activities and the subcellular distribution of Cd in young and old leaves from two different castor cultivars, after exposure to two different Cd concentrations, and explore the underlying mechanism of Cd detoxification focusing on antioxidant enzymes and subcellular compartmentalization. The Cd concentration, toxicity, and subcellular distribution, as well as superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activities were measured in Zibo-3 and Zibo-9 cultivars after exposure to two different concentrations of Cd (2mg/L and 5mg/L) for 10 days. This research revealed Cd accumulation characteristics in castor are root>stem>young leaf>old leaf. Castor tolerance was Cd dose exposure and the cultivars themselves dependent. Investigation of subcellular Cd partitioning showed that Cd accumulated mainly in the heat stable protein (HSP) and cellular debris fractions, followed by the Cd rich granule (MRG), heat denatured protein (HDP), and organelle fractions. With increasing Cd concentration in nutrient solution, the decreased detoxified fractions (BDM) and the increased Cd-sensitive fractions (MSF) in young leaves may indicate the increased Cd toxicity in castor cultivars. The BDM-Cd fractions or MSF-Cd in old leaves may be linked with Cd tolerance of different cultivars of castor. The antioxidant enzymes that govern Cd detoxification were not found to be active in leaves. Taken together, these results indicate Cd tolerance and toxicity in castor can be explained by subcellular partitioning.

  18. Comparison on cellular mechanisms of iron and cadmium accumulation in rice: prospects for cultivating Fe-rich but Cd-free rice.

    PubMed

    Gao, Lei; Chang, Jiadong; Chen, Ruijie; Li, Hubo; Lu, Hongfei; Tao, Longxing; Xiong, Jie

    2016-12-01

    Iron (Fe) is essential for rice growth and humans consuming as their staple food but is often deficient because of insoluble Fe(III) in soil for rice growth and limited assimilation for human bodies, while cadmium (Cd) is non-essential and toxic for rice growth and humans if accumulating at high levels. Over-accumulated Cd can cause damage to human bodies. Selecting and breeding Fe-rich but Cd-free rice cultivars are ambitious, challenging and meaningful tasks for researchers. Although evidences show that the mechanisms of Fe/Cd uptake and accumulation in rice are common to some extent as a result of similar entry routes within rice, an increasing number of researchers have discovered distinct mechanisms between Fe/Cd uptake and accumulation in rice. This comprehensive review systematically elaborates and compares cellular mechanisms of Fe/Cd uptake and accumulation in rice, respectively. Mechanisms for maintaining Fe homeostasis and Cd detoxicification are also elucidated. Then, effects of different fertilizer management on Fe/Cd accumulation in rice are discussed. Finally, this review enumerates various approaches for reducing grain Cd accumulation and enhancing Fe content in rice. In summary, understanding of discrepant cellular mechanisms of Fe/Cd accumulation in rice provides guidance for cultivating Fe-fortified rice and has paved the way to develop rice that are tolerant to Cd stress, aiming at breeding Fe-rich but Cd-free rice.

  19. Synthesis and characterization of a cadmium germanium phosphate CdGe(OH){sub 3}PO{sub 4} with an open framework

    SciTech Connect

    Liu Yan; Yang Xiaoli; Wang Guili; Zhang Jun; Li Yizhi; Du Hongbin You Xiaozeng

    2008-09-15

    A new three-dimensional (3D) framework cadmium germanium phosphate, CdGe(OH){sub 3}PO{sub 4} was synthesized by solvothermal methods. The crystal structure of CdGe(OH){sub 3}PO{sub 4} was established by single-crystal X-ray diffraction: CdGeH{sub 3}O{sub 7}P, Orthorhombic, Cmca, a=7.1415(7) A, b=10.9034(1) A, c=13.1098(1) A, Z=8, R{sub 1}=0.0365 (F{sup 2}>2{sigma}(F{sup 2}) and wR{sub 2}=0.0985 (all data). The framework of CdGe(OH){sub 3}PO{sub 4} is built by a mixed network of GeO{sub 6}, CdO{sub 6} octahedra and PO{sub 4} tetrahedra, which are linked to form a 3-membered ring (3-MR). The GeO{sub 6} and CdO{sub 6} octahedra share common vertexes and edges, respectively, to form one-dimensional (1D) Ge-O-Ge and Cd-O-Cd chains, which are further connected forming corrugated Ge-O-Cd layers. The layers are linked by PO{sub 4} tetrahedra, leading to a 3D open-framework structure with 3- and 6-MR channels. - Graphical abstract: A new three-dimensional framework cadmium germanium phosphate, CdGe(OH){sub 3}PO{sub 4} was synthesized by solvothermal methods. The framework of CdGe(OH){sub 3}PO{sub 4} is built by a mixed network of GeO{sub 6} octahedra, CdO{sub 6} octahedra and PO{sub 4} tetrahedra and contains a network of one-dimensional 3 and 6-membered ring channels. It belongs to a class of metal germanium phosphates with an open framework.

  20. Geochemical Transformation of Cadmium (Cd) from Creek to Paddy Fields in W Thailand

    NASA Astrophysics Data System (ADS)

    Kosolsaksakul, Peerapat; Graham, Margaret; Farmer, John

    2013-04-01

    Extensive Cd contamination of paddy soils in Tak Province, western Thailand, a consequence of Zn mining activities, was first established in 2005 and medical studies showed that the health of local communities was being impaired. Mae Tao, Tak Province, comprising many paddy fields and irrigation canals, has been selected for this study of the geochemical transformation of Cd from the contamination source in the mountainous region to the east of the study site through the community irrigation system to the paddy soils. The aim of this research is to (i) investigate the geochemical transformation of Cd as it is transported from the main irrigation creek through the canals and to the paddy fields, (ii) assess the availability of Cd to rice plants, which may be affected by both chemical and physical factors, and (iii) trial some practical treatments to minimise Cd concentrations in rice grains. Soils, irrigation canal sediments and water samples were collected during the dry season and at the onset of the rainy season. Rice samples were collected at harvesting time and samples of soil fertiliser were also obtained. Water samples were filtered, ultrafiltered and analysed by ICP-MS whilst sub-samples of dried, ground soils and sediments were first subjected to micro-wave assisted acid digestion (modified US EPA method 3052). XRD and SEM-EDX methods were used for mineralogical characterisation and selective chemical extractions have assisted in the characterisation of solid phase Cd associations. Soil Cd concentrations were in the range 2.5-87.6 µg g-1, with higher values being obtained for fields furthest from the main creek. Although current irrigation water Cd inputs are low (mean 1.9 μg L-1; flood period), high loads of suspended particles still contribute additional Cd (4.2-9.8 µg L-1) to the paddy fields. For bioavailability assessment by a 3-step BCR sequential extraction, 70-90% Cd was in the exchangeable; HOAc-extractable fraction. That indicated that most of

  1. Properties of RF sputtered cadmium telluride (CdTe) thin films: Influence of deposition pressure

    NASA Astrophysics Data System (ADS)

    Kulkarni, R. R.; Pawbake, A. S.; Waykar, R. G.; Rondiya, S. R.; Jadhavar, A. A.; Pandharkar, S. M.; Karpe, S. D.; Diwate, K. D.; Jadkar, S. R.

    2016-04-01

    Influence of deposition pressure on structural, morphology, electrical and optical properties of CdTe thin films deposited at low substrate temperature (100°C) by RF magnetron sputtering was investigated. The formation of CdTe was confirmed by low angle XRD and Raman spectroscopy. The low angle XRD analysis revealed that the CdTe films have zinc blende (cubic) structure with crystallites having preferred orientation in (111) direction. Raman spectra show the longitudinal optical (LO) phonon mode peak ˜ 165.4 cm-1 suggesting high quality CdTe film were obtained over the entire range of deposition pressure studied. Scanning electron microscopy analysis showed that films are smooth, homogenous, and crack-free with no evidence of voids. The EDAX data revealed that CdTe films deposited at low deposition pressure are high-quality stoichiometric. However, for all deposition pressures, films are rich in Cd relative to Te. The UV-Visible spectroscopy analysis show the blue shift in absorption edge with increasing the deposition pressure while the band gap show decreasing trend. The highest electrical conductivity was obtained for the film deposited at deposition pressure 1 Pa which indicates that the optimized deposition pressure for our sputtering unit is 1 Pa. Based on the experimental results, these CdTe films can be useful for the application in the flexible solar cells and other opto-electronic devices.

  2. Toxicity of cadmium sulfide (CdS) nanoparticles against Escherichia coli and HeLa cells.

    PubMed

    Hossain, Sk Tofajjen; Mukherjee, Samir Kumar

    2013-09-15

    The present study endeavours to assess the toxic effect of synthesized CdS nanoparticles (NPs) on Escherichia coli and HeLa cells. The CdS NPs were characterized by DLS, XRD, TEM and AFM studies and the average size of NPs was revealed as ∼3 nm. On CdS NPs exposure bacterial cells changed morphological features to filamentous form and damage of the cell surface was found by AFM study. The expression of two conserved cell division components namely ftsZ and ftsQ in E. coli was decreased both at transcriptional and translational levels upon CdS NPs exposure. CdS NPs inhibited proper cell septum formation without affecting the nucleoid segregation. Viability of HeLa cells declined with increasing concentration of CdS NPs and the IC₅₀ value was found to be 4 μg/mL. NPs treated HeLa cells showed changed morphology with condensed and fragmented nuclei. Increased level of reactive oxygen species (ROS) was found both in E. coli and HeLa cells on CdS NPs exposure. The inverse correlation between declined cell viabilities and elevated ROS level suggested that oxidative stress seems to be the key event by which NPs induce toxicity both in E. coli and HeLa cells.

  3. Transcriptional regulation of metal transport genes and mineral nutrition during acclimatization to cadmium and zinc in the Cd/Zn hyperaccumulator, Thlaspi caerulescens (Ganges population).

    PubMed

    Küpper, Hendrik; Kochian, Leon V

    2010-01-01

    We investigated changes in mineral nutrient uptake and cellular expression levels for metal transporter genes in the cadmium (Cd)/zinc (Zn) hyperaccumulator, Thlaspi caerulescens during whole plant and leaf ontogenesis under different long-term treatments with Zn and Cd. Quantitative mRNA in situ hybridization (QISH) revealed that transporter gene expression changes not only dependent on metal nutrition/toxicity, but even more so during plant and leaf development. The main mRNA abundances found were: ZNT1, mature leaves of young plants; ZNT5, young leaves of young plants; MTP1 (= ZTP1 = ZAT), young leaves of both young and mature plants. Surprisingly different cellular expression patterns were found for ZNT1 and ZNT5, both belonging to the ZIP family of transition metal transporters: ZNT1, photosynthetic mesophyll and bundle sheath cells; ZNT5, nonphotosynthetic epidermal metal storage cells and bundle sheath cells. Thus, ZNT1 may function in micronutrient nutrition while ZNT5 may be involved in metal storage associated with hyperaccumulation. Cadmium inhibited the uptake of Zn, iron (Fe) and manganese (Mn), probably by competing for transporters or by interfering with the regulation of transporter gene expression. Cadmium-induced changes in cellular expression for ZNT1, ZNT5 and MTP1 could also be part of plant acclimatization to Cd toxicity. Defence against Cd toxicity involved enhanced uptake of magnesium (Mg), calcium (Ca) and sulphur (S).

  4. Assessment of Pb, Cd, Cr and Ag leaching from electronics waste using four extraction methods.

    PubMed

    Keith, Ashley; Keesling, Kara; Fitzwater, Kendra K; Pichtel, John; Houy, Denise

    2008-12-01

    Heavy metals present in electronic components may leach upon disposal and therefore pose significant environmental hazards. The potential leaching of Pb, Cd, Cr and Ag from PC cathode ray tubes, printed circuit boards (PCBs), PC mice, TV remote controls, and mobile phones was assessed. After controlled crushing, each component was extracted using the Toxicity Characteristic Leaching Procedure (TCLP), EPA Method 1312 (SPLP), NEN 7371 (Dutch Environmental Agency), and DIN S4 (Germany). The TCLP consistently leached the greatest amounts of Pb from all components. The SPLP, NEN 7371 and DIN S4 extracted relatively small amounts of metals compared with the TCLP and were not considered effective as leaching tests for e-waste. The smallest size fraction (< 2 mm) of CRT glass and PCBs leached significantly (p < 0.05) highest Pb via the TCLP. A modified TCLP removed 50.9% more extractable Pb compared with the conventional procedure.

  5. Photocatalytic activity of CdS and Ag(2)S quantum dots deposited on poly(amidoamine) functionalized carbon nanotubes.

    PubMed

    Neelgund, Gururaj M; Oki, Aderemi

    2011-10-02

    Two novel ternary nanocatalysts, f-MWCNTs-CdS and f-MWCNTs-Ag(2)S were successfully constructed by covalent grafting of fourth generation (G4) hyperbranched, crosslinked poly(amidoamine) (PAMAM) to carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) and subsequent deposition of CdS or Ag(2)S quantum dots (QDs). The structural transformation, surface potential, and morphology of functionalized MWCNTs (f-MWCNTs) and nanocatalysts were characterized by UV-vis spectrophotometer, Fourier transform infrared spectroscopy, powder X-ray diffraction, Raman spectroscopy, thermogravimetric analysis, scanning electron microscopy and energy dispersive spectroscopy. Transmission electron microscopy reveals the effective anchoring of QDs on f-MWCNTs. The catalytic activity of nanocatalysts was evaluated by photodegradation of methyl orange under illumination of UV light. The coupling of MWCNTs, PAMAM and CdS or Ag(2)S QDs significantly enhanced the catalytic efficiency of nanocatalysts. The rate constants for degradation of methyl orange in presence of nanocatalysts were calculated using the Langmuir-Hinshelwood model. Overall, the excellence in photodegradation was accomplished by hybridizing f-MWCNTs with CdS or Ag(2)S.

  6. Evolution of different morphologies of CdS nanoparticles by thermal decomposition of bis(thiourea)cadmium chloride in various solvents

    NASA Astrophysics Data System (ADS)

    Gaur, Rama; Jeevanandam, P.

    2015-03-01

    CdS nanoparticles with different morphologies have been synthesized by thermal decomposition of bis(thiourea)cadmium chloride in different solvents without the use of any ligand/surfactant. CdS nanoparticles with pyramid, sponge-like and hexagonal disc-like morphologies were obtained in diphenyl ether (DPE), 1-octadecene (ODE) and ethylene glycol (EG), respectively. In addition, CdS nanoparticles with unique morphologies were obtained when the decomposition of the complex was carried out in mixed solvents (DPE-EG and ODE-EG). Extensive characterization of the CdS nanoparticles was carried out using powder X-ray diffraction, FT-IR spectroscopy, thermal analysis, field-emission scanning electron microscopy, diffuse reflectance spectroscopy and photoluminescence spectroscopy, and detailed mechanism of the formation of CdS nanoparticles with different morphologies in various solvents has been proposed.

  7. Validation of an analytical method for the determination of cadmium (Cd) in fish by atomic absorption spectrometry with electrothermal atomisation.

    PubMed

    Costa, L C S M; Neto, A P N; Araújo, M Q; Melo, M C C; Furtado, D M S; Kikuchi, A N S

    2012-01-01

    The validation of an analytical method was carried out for the determination of cadmium (Cd) in fish. The method was based on sample digestion in a microwave oven and subsequent reading using an atomic absorption spectrometer with a graphite furnace. The factorial design of experiments was applied to assess method ruggedness using the methodology of Box et al. [Box GEP, Hunter WG, Hunter JS. 1978. Statistics for experiments: an introduction to design, data analysis and model building. New York (NY): Wiley], studying the influence of sample mass, volume and concentration of acid used for sample digestion and the volume of modifier used. To study the possible matrix effect in the determination of Cd, the standard addition method was also performed. The results were treated using the OLS method. For the normality test a homoskedastic distribution was observed for the developed method and the results were adjusted to the statistical model proposed. F-tests and Student's t-tests indicated that there was no matrix effect on the calibration curve between the concentration range 1.0-10.0 µg Cd l(-1). Parameters such as selectivity, precision, decision limit, detection capability and limit of quantification were established by the method of standard addition to blank samples. The limit of quantification was 6.8 µg kg(-1). Accuracy, which was evaluated by using a certified reference material, was 107.0%. The recovery of the spiked analyte was 93.69% for the concentration of 50 µg kg(-1). Precision was defined by the coefficient of variation observed (Horrat value), estimated in terms of repeatability and reproducibility, and the values were below the limit, which is 2.0. The validation procedure confirmed the suitability of the method.

  8. Cadmium-free sugar-chain-immobilized fluorescent nanoparticles containing low-toxicity ZnS-AgInS2 cores for probing lectin and cells.

    PubMed

    Shinchi, Hiroyuki; Wakao, Masahiro; Nagata, Nonoka; Sakamoto, Masaya; Mochizuki, Eiko; Uematsu, Taro; Kuwabata, Susumu; Suda, Yasuo

    2014-02-19

    Sugar chains play a significant role in various biological processes through sugar chain-protein and sugar chain-sugar chain interactions. To date, various tools for analyzing sugar chains biofunctions have been developed. Fluorescent nanoparticles (FNPs) functionalized with carbohydrate, such as quantum dots (QDs), are an attractive imaging tool for analyzing carbohydrate biofunctions in vitro and in vivo. Most FNPs, however, consist of highly toxic elements such as cadmium, tellurium, selenium, and so on, causing problems in long-term bioimaging because of their cytotoxicity. In this study, we developed cadmium-free sugar-chain-immobilized fluorescent nanoparticles (SFNPs) using ZnS-AgInS2 (ZAIS) solid solution nanoparticles (NPs) of low or negligible toxicity as core components, and investigated their bioavailability and cytotoxicity. SFNPs were prepared by mixing our originally developed sugar-chain-ligand conjugates with ZAIS/ZnS core/shell NPs. In binding experiments with lectin, the obtained ZAIS/ZnS SFNPs interacted with an appropriate lectin to give specific aggregates, and their binding interaction was visually and/or spectroscopically detected. In addition, these SFNPs were successfully utilized for cytometry analysis and cellular imaging in which the cell was found to possess different sugar-binding properties. The results of the cytotoxicity assay indicated that SFNPs containing ZAIS/ZnS have much lower toxicity than those containing cadmium. These data strongly suggest that our designed SFNPs can be widely utilized in various biosensing applications involved in carbohydrates.

  9. Nanoparticle-electrode collision processes: The electroplating of bulk cadmium on impacting silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Zhou, Yi-Ge; Rees, Neil V.; Compton, Richard G.

    2011-08-01

    We report, for the first time, the bulk deposition (electroplating) of a metal onto nanoparticles during collisions with an inert electrode surface. Experiments show that for silver nanoparticles, multiple layers of Cd atoms can be electroplated onto the AgNPs from aqueous Cd 2+ during collisions with a glassy carbon electrode held at a suitably reducing potential, and an average of 19 atomic layers of cadmium are found to be deposited in the few milliseconds that the NP is in contact with the electrode. For comparison, results are also presented for the underpotential deposition of Cd onto AgNPs under similar conditions.

  10. Preparation, crystal structure, and thermal stability of the cadmium sulfide nanoclusters Cd6S44+ and Cd2Na2S4+in the sodalite cavities of zeolite A (LTA).

    PubMed

    Kim, Seok Han; Heo, Nam Ho; Kim, Ghyung Hwa; Hong, Suk Bong; Seff, Karl

    2006-12-28

    The crystal structure and thermal stability of two cadmium sulfide nanoclusters prepared in zeolite A (LTA) have been studied by XPS, TGA, and single-crystal and powder XRD. The crystal structures of Cd2.4Na3.2(Cd6S4)0.4(Cd2Na2S)0.6(H2O)> or =5.8[Si12Al12O48]-LTA (a = 12.2919(7) A, crystal 1 (hydrated)) and /Cd4Na2(Cd2O)(Na2O)/[Si12Al12O48]-LTA (a = 12.2617(4) A, crystal 2 (dehydrated)) were determined by single-crystal methods in the cubic space group Pm3m at 294(1) K. Crystal 1 was prepared by ion exchange of Na12-LTA in an aqueous stream 0.05 M in Cd2+, followed by washing in a stream of water, followed by reaction in an aqueous stream 0.05 M in Na2S. Crystal 2 was made by dehydrating crystal 1 at 623 K and 1 x 10(-6) Torr for 3 days. In crystal 1, Cd6S4(4+) nanoclusters were found in and extending out of about 40% of the sodalite cavities. Central to each Cd6S4(4+) cluster is a Cd4S4 unit (interpenetrating Cd2+ and S2- tetrahedra with near Td symmetry, Cd-S = 2.997(24) A, Cd-S-Cd = 113.8(12) degrees, and S-Cd-S = 58.1(24) degrees). Each of the two remaining Cd2+ ions bonds radially through a 6-ring of the zeolite framework to a sulfide ion of this Cd4S4 unit (Cd-S = 2.90(8) A). In each of the remaining 60% of the sodalite cavities of crystal 1, a planar Cd2Na2S4+ cluster was found (Cd-S/Na-S = 2.35(5)/2.56(14) A and Cd-S-Cd/Na-S-Na = 122(5)/92(7) degrees). Cd6S4(4+) and Cd2Na2S4+ are stable within the zeolite up to about 700 K in air. Upon vacuum dehydration at 623 K, all sulfur was lost (crystal 2). Instead as anions, only two oxide ions remain per sodalite unit. One bridges between two Cd2+ ions (Cd2O2+, Cd-O = 2.28(3) A) and the other between two Na+ ions (Na2O, Na-O = 2.21(10) A).

  11. Synthesis and characterization of a cadmium bipyridinium compound (CdCl{sub 4})(N,N'-dimethyl-2,2'-bipyridinium)

    SciTech Connect

    Luo, Hui; Zhu, Li-Cheng; Wang, Qi

    2015-12-15

    A cadmium bipyridinium compound (CdCl{sub 4})(N,N'-dimethyl-2,2'-bipyridinium), in which the (N,N'-dimethyl-2,2'-bipyridinium){sup 2+} moieties were generated in situ, has been prepared via solvothermal reactions and structurally characterized with single crystal X-ray diffraction method. Fluorescence measurement revealed a broad and strong emission band in the blue region.

  12. Isotherm studies for the determination of Cd (II) ions removal capacity in living biomass of a microalga with high tolerance to cadmium toxicity.

    PubMed

    Torres, Enrique; Mera, Roi; Herrero, Concepción; Abalde, Julio

    2014-11-01

    The biosorption characteristics of Cd (II) ions using the living biomass of the marine diatom Phaeodactylum tricornutum were investigated. This microalga is a highly tolerant species to cadmium toxicity; for this reason, it is interesting to know its potential for use in the removal of this metal. The use of living biomass offers better possibilities than that of dead biomass since cadmium can also be bioaccumulated inside the cells. For this purpose, tolerant species are necessary. P. tricornutum is within this category with an EC50,96h of 19.1 ± 3.5 mg Cd (II)/L, and in the present manuscript, it is demonstrated that this microalga has a very good potential for bioremediation of Cd (II) ions in saline habitats. Cadmium removed by the cells was divided into three fractions: total, intracellular and bioadsorbed. The experiments were conducted for 96 h in natural seawater with a concentration range of 1-100 mg Cd (II)/L. Each fraction was characterized every 24 h by sorption isotherms. The experimental isotherm data were analyzed using the Langmuir, Freundlich, Dubinin-Radushkevich and Temkin equations. The biosorption was well described by Langmuir isotherm followed by Freundlich. The worst model was Temkin. The biosorption capacity of this microalga for Cd (II) ions was found to be 67.1 ± 3.2 mg/g after 96 h with approximately 40 % of this capacity in the intracellular fraction. The bioconcentration factor determined was 2,204.7 after 96 h and with an initial Cd (II) concentration of 1 mg/L.

  13. Transcriptional up-regulation of genes involved in photosynthesis of the Zn/Cd hyperaccumulator Sedum alfredii in response to zinc and cadmium.

    PubMed

    Tang, Lu; Yao, Aijun; Ming Yuan; Tang, Yetao; Liu, Jian; Liu, Xi; Qiu, Rongliang

    2016-12-01

    Zinc (Zn) and cadmium (Cd) are two closely related chemical elements with very different biological roles in photosynthesis. Zinc plays unique biochemical functions in photosynthesis. Previous studies suggested that in some Zn/Cd hyperaccumulators, many steps in photosynthesis may be Cd tolerant or even Cd stimulated. Using RNA-seq data, we found not only that Cd and Zn both up-regulated the CA1 gene, which encodes a β class carbonic anhydrase (CA) in chloroplasts, but that a large number of other Zn up-regulated genes in the photosynthetic pathway were also significantly up-regulated by Cd in leaves of the Zn/Cd hyperaccumulator Sedum alfredii. These genes also include chloroplast genes involved in transcription and translation (rps18 and rps14), electron transport and ATP synthesis (atpF and ccsA), Photosystem II (PSBI, PSBM, PSBK, PSBZ/YCF9, PSBO-1, PSBQ, LHCB1.1, LHCB1.4, LHCB2.1, LHCB4.3 and LHCB6) and Photosystem I (PSAE-1, PSAF, PSAH2, LHCA1 and LHCA4). Cadmium and Zn also up-regulated the VAR1 gene, which encodes the ATP-dependent zinc metalloprotease FTSH 5 (a member of the FtsH family), and the DAG gene, which influences chloroplast differentiation and plastid development, and the CP29 gene, which supports RNA processing in chloroplasts and has a potential role in signal-dependent co-regulation of chloroplast genes. Further morphological parameters (dry biomass, cross-sectional thickness, chloroplast size, chlorophyll content) and chlorophyll fluorescence parameters confirmed that leaf photosynthesis of S. alfredii responded to Cd much as it did to Zn, which will contribute to our understanding of the positive effects of Zn and Cd on growth of this plant.

  14. Enhanced photoelectrochemical performance of ZnO nanorod arrays decorated with CdS shell and Ag2S quantum dots

    NASA Astrophysics Data System (ADS)

    Holi, Araa Mebdir; Zainal, Zulkarnain; Talib, Zainal Abidin; Lim, Hong-Ngee; Yap, Chi-Chin; Chang, Sook-Keng; Ayal, Asmaa Kadim

    2017-03-01

    Ternary nanostructured Ag2S/CdS/ZnO thin film was prepared by using a simple low-cost hydrothermal method. The hexagonal phase of ZnO nanorods and CdS shells combined with monoclinic Ag2S quantum dots resulted in improved optical and photoelectrochemical properties. CdS shell with high absorption property efficiently compliment the energy levels of ZnO and improved the ability of light absorption. Furthermore, narrow band gap Ag2S also played a vital part in the light harvesting. The photoelectrochemical performance of the ternary nanostructured Ag2S/CdS/ZnO NRs was investigated in a mixture of Na2S and Na2SO3 aqueous solutions under visible light illumination. The Ag2S/CdS/ZnO NRs were found to be more efficient than ZnO NRs, CdS/ZnO NRs, and Ag2S/ZnO NRs as this particular sample gave a maximum photocurrent of 5.69 mA cm-2, which is around 2 and 1.5 times greater than CdS/ZnO NRs and Ag2S/ZnO NRs, respectively. Besides that, it was found that this ternary film possessed 15 times higher photocurrent density than plain ZnO NRs. This is attributed to the larger amount of visible light absorbed by the ternary nanostructured composite.

  15. Fabrication of ITO/Ag3SbS3/CdX (X = S, Se) thin film heterojunctions for photo-sensing applications

    NASA Astrophysics Data System (ADS)

    Daniel, T.; Henry, J.; Mohanraj, K.; Sivakumar, G.

    2016-11-01

    Thin film heterojunctions of Ag3SbS3/CdX (X = S, Se) are deposited on a glass substrate coated with SnO2:In (ITO). The films were characterized by x-ray diffraction (XRD), atomic force microscopy (AFM), UV-visible spectroscopy, photoluminescence spectroscopy, field emission scanning electron microscopy and I-V analysis. XRD reveals the monoclinic structure of Ag3SbS3 and a fcc structure for both CdS and CdSe thin films. The AFM images clearly show the distinct morphological features (nanopyramids, wedge-shaped and rectangular nanorod-like grains). From the I-V studies, under illumination, an ITO/Ag3SbS3/CdS heterojunction produces a higher photocurrent (12.4 mA) than that an ITO/Ag3SbS3/CdSe heterojunction (1.34 mA).

  16. Exciton-plasmon interactions between CdS quantum dots and Ag nanoparticles in photoelectrochemical system and its biosensing application.

    PubMed

    Zhao, Wei-Wei; Yu, Pei-Pei; Shan, Yun; Wang, Jing; Xu, Jing-Juan; Chen, Hong-Yuan

    2012-07-17

    With DNA as a rigid spacer, Ag nanoparticles (NPs) were bridged to CdS quantum dots (QDs) for the stimulation of exciton-plasmon interactions (EPI) in a photoelectrochemical (PEC) system. Due to their natural absorption overlap, the exciton of the QDs and the plasmon of Ag NPs could be induced simultaneously. The EPI resonant nature enabled manipulating photoresponse of the QDs via tuning interparticle distances. Specifically, the photocurrent of the QDs could be greatly attenuated and even be completely damped by the generated EPI. The work opens a different horizon for EPI investigation through an engineered PEC nanosystem, and provides a viable mechanism for new DNA sensing protocol.

  17. Material and detector properties of cadmium manganese telluride (Cd1-xMnxTe) crystals grown by the modified floating-zone method

    DOE PAGES

    Hossain, A.; Gu, G. D.; Bolotnikov, A. E.; ...

    2014-12-24

    We demonstrated the material- and radiation-detection properties of cadmium manganese telluride (Cd1-xMnxTe; x=0.06), a wide-band-gap semiconductor crystal grown by the modified floating-zone method. We investigated the presence of various bulk defects, such as Te inclusions, twins, and dislocations of several as-grown indium-doped Cd1-xMnxTe crystals using different techniques, viz., IR transmission microscopy, and chemical etching. We then fabricated four planar detectors from selected CdMnTe crystals, characterized their electrical properties, and tested their performance as room-temperature X- and gamma-ray detectors. Thus, our experimental results show that CMT crystals grown by the modified floating zone method apparently are free from Te inclusions. However,more » we still need to optimize our growth parameters to attain high-resistivity, large-volume single-crystal CdMnTe.« less

  18. Model optimization of cadmium and accumulation in switchgrass (Panicum virgatum L.): potential use for ecological phytoremediation in Cd-contaminated soils.

    PubMed

    Wang, Quanzhen; Gu, Muyu; Ma, Xiaomin; Zhang, Hongjuan; Wang, Yafang; Cui, Jian; Gao, Wei; Gui, Jing

    2015-11-01

    Soil pollution with heavy metals is an increasingly serious threat to the environment, food security, and human health. Therefore, it is urgent to develop economic and highly efficient soil restoration technology for environmental improvement; phytoremediation is an option that is safe, has low cost, and is environmentally friendly. However, in selecting hyperaccumulators or tolerant plants, theories and operation technologies for optimal restoration should be satisfied. In this study, the switchgrass growth response and performance of phytoextraction under the coupling effect of Cd and pH were investigated by evaluating seed germination, seedling growth, and the Cd content in the plant to evaluate the potential use of switchgrass as a phytoremediation plant in cadmium contaminated soil. This study conducted three sets of independent experiments with five levels of Cd concentrations, including two orthogonal matrix designs of combining Cd with pH values. The results showed that switchgrass was germinated well under all treatments (Cd concentration of 0-500 μM), but the seedling growth was significantly affected by Cd and pH, as shown by multivariate regression analyses. Hormesis was found during the growth of switchgrass plants exposed to low Cd concentrations under hydroponic conditions, and switchgrass plants were capable of developing with a Cd concentration of 100-175 μM and pH of 4.1-5.9. Mild acidic conditions can enhance the ability of Cd to accumulate in switchgrass. Switchgrass was moderately tolerant to Cd and may be used as a phytoremediation plant for Cd-contaminated soils in the future. Our results also suggest that hormetic effects should be taken into consideration in the phytoremediation of Cd-contaminated soils. We discuss the physiological and biochemical mechanisms contributing to the effective application of the plant for the phytoremediation of Cd-contaminated soils.

  19. Minimizing Reflectivity by Etching Microstructures in Mercury Cadmium Telluride (HgCdTe)

    DTIC Science & Technology

    2013-02-01

    untreated material. 15. SUBJECT TERMS HgCdTe, Microstructures 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18...mismatch), which is first grown on a silicon (Si) substrate. The MCT IR focal plane array (FPA) with a Si substrate is then interfaced to a Si...dimensions of the microstructures, beyond the limit of resolution, the effective index of refraction is a weighted average of the fill factor of the two

  20. From Ag{sub 2}Sb{sub 2}O{sub 6} to Cd{sub 2}Sb{sub 2}O{sub 7}: Investigations on an anion-deficient to ideal pyrochlore solid solution

    SciTech Connect

    Laurita, Geneva; Vielma, Jason; Winter, Florian; Berthelot, Romain; Largeteau, Alain; Pöttgen, Rainer; Schneider, G.; Subramanian, M.A.

    2014-02-15

    A complete solid solution between the anion-deficient pyrochlore Ag{sub 2}Sb{sub 2}O{sub 6} and the ideal pyrochlore Cd{sub 2}Sb{sub 2}O{sub 7} has been synthesized through the standard solid state ceramic method. Each composition has been characterized by various different techniques, including powder X-ray diffraction, optical spectroscopy, electron paramagnetic resonance and {sup 121}Sb Mössbauer spectroscopy. Computational methods based on density functional theory complement this investigation. Photocatalytic activity has been studied, and transport properties have been measured on pellets densified by spark plasma sintering. The analysis of the data collected from these various techniques enables a comprehensive characterization of the complete solid solution and revealed an anomalous behavior in the Cd-rich end of the solid solution, which has been proposed to arise from a possible radical O{sup −} species in small concentrations. - Graphical abstract: A complete solid solution between the anion-deficient pyrochlore Ag{sub 2}Sb{sub 2}O{sub 6} and the ideal pyrochlore Cd{sub 2}Sb{sub 2}O{sub 7} has been synthesized and investigated through various techniques including X-ray diffraction, electron paramagnetic spectroscopy, and {sup 121}Sb-Mössbauer spectroscopy. Optical and electrical measurements have been performed, and computational methods have been applied to determine the density of states. Photocatalytic activity was monitored by the degradation of Methylene Blue, and upon cadmium substitution, the degradation amount decreased, which is attributed primarily to the changing optical and electrical properties of the solid solution. Display Omitted - Highlights: • A complete solid solution between Ag{sub 2}Sb{sub 2}O{sub 6} and Cd{sub 2}Sb{sub 2}O{sub 7} has been synthesized. • XRD reveals a relatively constant lattice parameter as the series progresses. • Optical and electrical properties have been measured for the solid solution.

  1. Early genotoxic effects in gill cells and haemocytes of Dreissena polymorpha exposed to cadmium, B[a]P and a combination of B[a]P and Cd.

    PubMed

    Vincent-Hubert, Françoise; Arini, Adeline; Gourlay-Francé, Catherine

    2011-07-14

    The aim of this study was to assess the genotoxic potential of environmentally relevant concentrations of Cd on the zebra mussel, an important freshwater sentinel organism, and to determine the stability of DNA damage in gill cells and haemocytes. The oxidative DNA damage and the co-genotoxicity of Cd in combination with B[a]P were investigated. We measured DNA damage in haemocytes and gill cells of zebra mussels exposed for 11 days to a constant concentration of Cd (10μg/L), B[a]P (10μg/L) or the two combined chemicals (10μg/L+1μg/L). Enzymatic dissociation of gills with dispase gave the lower percentage DNA in tail, compared with collagenase/dispase or collagenase. Bioaccumulation of cadmium in the soft tissues of mussels exposed to CdCl(2) or CdCl(2)+B[a]P increased in a time-dependent manner indicating that both exposures were effective. Cd (10μg/L) is genotoxic only during the first 3 days of exposure in gill cells, while in haemocytes the genotoxicity of Cd was observed later. B[a]P (10μg/L) induced an early increase of DNA damage in gill cells (after 10h and 1 day), while in both gill cells and haemocytes, B[a]P caused a marked increase of DNA damage after 3 days of exposure. The Cd+B[a]P mixture decreased the DNA-damaging effect of Cd and B[a]P in both cell types. Cd induced an increase of DNA damage in Fpg-treated slides, indicating that Cd contributed to oxidative DNA damage. Cadmium induced a cytogenetic effect in gill cells, assessed by the number of micronuclei, throughout the duration of the exposure, while B[a]P did not induce any cytogenetic effect. B[a]P, Cd and Cd+B[a]P induced a transient increase in the number of bi-nucleated cells. Our data clearly show that gills are more sensitive to Cd and B[a]P, which makes them more suitable for future bio-monitoring studies.

  2. Labeling and in vivo visualization of transplanted adipose tissue-derived stem cells with safe cadmium-free aqueous ZnS coating of ZnS-AgInS2 nanoparticles

    PubMed Central

    Ogihara, Yusuke; Yukawa, Hiroshi; Kameyama, Tatsuya; Nishi, Hiroyasu; Onoshima, Daisuke; Ishikawa, Tetsuya; Torimoto, Tsukasa; Baba, Yoshinobu

    2017-01-01

    The facile synthesis of ZnS-AgInS2 (ZAIS) as cadmium-free QDs and their application, mainly in solar cells, has been reported by our groups. In the present study, we investigated the safety and the usefulness for labeling and in vivo imaging of a newly synthesized aqueous ZnS-coated ZAIS (ZnS-ZAIS) carboxylated nanoparticles (ZZC) to stem cells. ZZC shows the strong fluorescence in aqueous solutions such as PBS and cell culture medium, and a complex of ZZC and octa-arginine (R8) peptides (R8-ZZC) can achieve the highly efficient labeling of adipose tissue-derived stem cells (ASCs). The cytotoxicity of R8-ZZC to ASCs was found to be extremely low in comparison to that of CdSe-based QDs, and R8-ZZC was confirmed to have no influence on the proliferation rate or the differentiation ability of ASCs. Moreover, R8-ZZC was not found to induce the production of major inflammatory cytokines (TNF-α, IFN-γ, IL-12p70, IL-6 and MCP-1) in ASCs. Transplanted R8-ZZC-labeled ASCs could be quantitatively detected in the lungs and liver mainly using an in vivo imaging system. In addition, high-speed multiphoton confocal laser microscopy revealed the presence of aggregates of transplanted ASCs at many sites in the lungs, whereas individual ASCs were found to have accumulated in the liver. PMID:28059135

  3. Labeling and in vivo visualization of transplanted adipose tissue-derived stem cells with safe cadmium-free aqueous ZnS coating of ZnS-AgInS2 nanoparticles

    NASA Astrophysics Data System (ADS)

    Ogihara, Yusuke; Yukawa, Hiroshi; Kameyama, Tatsuya; Nishi, Hiroyasu; Onoshima, Daisuke; Ishikawa, Tetsuya; Torimoto, Tsukasa; Baba, Yoshinobu

    2017-01-01

    The facile synthesis of ZnS-AgInS2 (ZAIS) as cadmium-free QDs and their application, mainly in solar cells, has been reported by our groups. In the present study, we investigated the safety and the usefulness for labeling and in vivo imaging of a newly synthesized aqueous ZnS-coated ZAIS (ZnS-ZAIS) carboxylated nanoparticles (ZZC) to stem cells. ZZC shows the strong fluorescence in aqueous solutions such as PBS and cell culture medium, and a complex of ZZC and octa-arginine (R8) peptides (R8-ZZC) can achieve the highly efficient labeling of adipose tissue-derived stem cells (ASCs). The cytotoxicity of R8-ZZC to ASCs was found to be extremely low in comparison to that of CdSe-based QDs, and R8-ZZC was confirmed to have no influence on the proliferation rate or the differentiation ability of ASCs. Moreover, R8-ZZC was not found to induce the production of major inflammatory cytokines (TNF-α, IFN-γ, IL-12p70, IL-6 and MCP-1) in ASCs. Transplanted R8-ZZC-labeled ASCs could be quantitatively detected in the lungs and liver mainly using an in vivo imaging system. In addition, high-speed multiphoton confocal laser microscopy revealed the presence of aggregates of transplanted ASCs at many sites in the lungs, whereas individual ASCs were found to have accumulated in the liver.

  4. Particulate contacts to Si and CdTe: Al, Ag, Hg-Cu-Te, and Sb-Te

    NASA Astrophysics Data System (ADS)

    Schulz, Douglas L.; Ribelin, Rosine; Curtis, Calvin J.; Ginley, David S.

    1999-03-01

    Our team has been investigating the use of particle-based contacts in both Si and CdTe solar cell technologies. First, in the area of contacts to Si, powders of Al and Ag prepared by an electroexplosion process have been characterized by transmission electron microscopy (TEM), TEM elemental determination X-ray spectroscopy (TEM-EDS), and TEM electron diffraction (TEM-ED). These Al and Ag particles were slurried and tested as contacts to p- and n-type silicon wafers, respectively. Linear current-voltage (I-V) was observed for Ag on n-type Si, indicative of an ohmic contact, whereas the Al on p-type Si sample was non-ideal. A wet-chemical surface treatment was performed on one Al sample and TEM-EDS indicated a substantial decrease in the O contaminant level. The treated Al on p-type Si films exhibited linear I-V after annealing. Second, in the area of contacts to CdTe, particles of Hg-Cu-Te and Sb-Te have been applied as contacts to CdTe/CdS/SnO2 heterostructures prepared by the standard NREL protocol. First, Hg-Cu-Te and Sb-Te were prepared by a metathesis reaction. After CdCl2 treatment and NP etch of the CdTe layer, particle contacts were applied. The Hg-Cu-Te contacted cells exhibited good electrical characteristics, with Voc>810 mV and efficiencies > 11.5% for most cells. Although Voc>800 mV were observed for the Sb-Te contacted cells, efficiencies in these devices were limited to 9.1% presumably by a large series resistance (>20 Ω) observed in all samples.

  5. Efficient visible-light photocatalytic activity by band alignment in mesoporous ternary polyoxometalate-Ag2S-CdS semiconductors

    NASA Astrophysics Data System (ADS)

    Kornarakis, I.; Lykakis, I. N.; Vordos, N.; Armatas, G. S.

    2014-07-01

    Porous multicomponent semiconductor materials show improved photocatalytic performance due to the large and accessible pore surface area and high charge separation efficiency. Here we report the synthesis of well-ordered porous polyoxometalate (POM)-Ag2S-CdS hybrid mesostructures featuring a controllable composition and high photocatalytic activity via a two-step hard-templating and topotactic ion-exchange chemical process. Ag2S compounds and polyoxometalate cluster anions with different reduction potentials, such as PW12O403-, SiW12O404- and PMo12O403-, were employed as electron acceptors in these ternary heterojunction photocatalysts. Characterization by small-angle X-ray scattering, X-ray diffraction, transmission electron microscopy and N2 physisorption measurements showed hexagonal arrays of POM-Ag2S-CdS hybrid nanorods with large internal BET surface areas and uniform mesopores. The Keggin structure of the incorporated POM clusters was also verified by elemental X-ray spectroscopy microanalysis, infrared and diffuse-reflectance ultraviolet-visible spectroscopy. These new porous materials were implemented as visible-light-driven photocatalysts, displaying exceptional high activity in aerobic oxidation of various para-substituted benzyl alcohols to the corresponding carbonyl compounds. Our experiments show that the spatial separation of photogenerated electrons and holes at CdS through the potential gradient along the CdS-Ag2S-POM interfaces is responsible for the increased photocatalytic activity.Porous multicomponent semiconductor materials show improved photocatalytic performance due to the large and accessible pore surface area and high charge separation efficiency. Here we report the synthesis of well-ordered porous polyoxometalate (POM)-Ag2S-CdS hybrid mesostructures featuring a controllable composition and high photocatalytic activity via a two-step hard-templating and topotactic ion-exchange chemical process. Ag2S compounds and polyoxometalate cluster

  6. Red florescent Ag2S-CdS hybrid nanoparticles prepared by a one pot and rapid microwave method

    NASA Astrophysics Data System (ADS)

    Karimipour, Masoud; Molaei, Mehdi

    2016-03-01

    In this work, Ag2S-CdS hybrid composite with novel luminescence property was synthesized using a one pot and rapid microwave method. Structural analysis by means of XRD and TEM obtained the formation of the composite. Optical spectroscopy by means of UV-Vis and Photoluminescence measurements revealed that the functional composite has an intensive red light emission at 657 nm with a large stocks shift of about 150 nm. The quantum efficiency of the prepared hybrid material in red region is 10% which is comparable with the efficiency of pure CdS (11%) with green emission. [Figure not available: see fulltext.

  7. Diverse strategies conferring extreme cadmium (Cd) tolerance in the dark septate endophyte (DSE), Exophiala pisciphila: evidence from RNA-seq data.

    PubMed

    Zhao, Dake; Li, Tao; Shen, Mi; Wang, Junling; Zhao, Zhiwei

    2015-01-01

    Dark septate endophytes (DSE) ubiquitously colonize the roots of plants growing in extreme heavy metals (HMs)-contaminated soils. Little is known about the overall molecular response of DSE to excessive HMs. Therefore, RNA-seq was performed through Illumina Hiseq 2000 sequencing based on two cDNA libraries of the DSE strain Exophiala pisciphila, cultured under cadmium (Cd)-free and Cd-stressed conditions, and 21,376 unigenes were generated. In total, 575 differentially expressed genes (DEGs) were obtained. Approximately 40% of the DEGs (228 unigenes) were involved in 10 well-known HMs-tolerant pathways, conferring the extreme cadmium (Cd) tolerance of E. pisciphila, including metal ion binding and transportation, organic acid metabolism and transportation, reactive oxygen species (ROS) scavenging, redox homeostasis, transcription factors production, sulfate assimilation, DNA repair and cell wall integrity maintenance, etc. Our results indicate that integral tactics associated with the collaboration of extracellular and intracellular mechanisms contribute to the enhanced HMs tolerance of this fungus. This study represents the first investigation of the transcriptome of DSE under Cd stress, and our results provide valuable information for future molecular studies of HMs tolerance in fungi.

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

    PubMed

    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.

  9. Effects of morphology, diameter and periodic distance of the Ag nanoparticle periodic arrays on the enhancement of the plasmonic field absorption in the CdSe quantum dots

    NASA Astrophysics Data System (ADS)

    Kohnehpoushi, Saman; Eskandari, Mehdi; Ahmadi, Vahid; Yousefirad, Mansooreh; Nabavi, Elham

    2016-09-01

    In this work, the numerical calculations of plasmonic field absorption of Ag nanoparticles (Ag NPs) periodic arrays in the CdSe quantum dot (QD) film are investigated by the three-dimensional finite difference time domain (FDTD). Diameter (D), periodic distance (P), and morphology effects of Ag NPs are investigated on the improvement of the plasmonic field absorption in CdSe QD film. Results show that plasmonic field absorption in CdSe QD film is enhanced with reduction of D of Ag NPs until 5 nm and reduces thereafter. It is observed that with raising D of Ag NPs, optimum plasmonic field absorption in CdSe QD film is shifted toward the higher P. Moreover, with varying morphology of Ag NPs from spherical to cylindrical, cubic, ringing and pyramid, the plasmonic field absorption is considerably enhanced in CdSe QD film and position of quadrupole plasmon mode (QPPM) is shifted toward further wavelength. For cylindrical Ag NPs, the QPPM intensity increased with raising height (H) until 15 nm and reduces thereafter.

  10. Anodic electrosynthesis of cadmium selenide thin films; Characterization and comparison with the passive/transpassive behavior of CdX (X = S,Te) counterpart

    SciTech Connect

    Ham, D.; Mishra, K.K.; Rajeshwar, K. )

    1991-01-01

    This paper reports on cadmium selenide thin films electrosynthesized by an anodic route employing alkaline selenide solutions. The thermodynamic aspects of the electrodeposition chemistry were first explored via Pourbaix diagrams; the kinetic aspects were studied by linear sweep voltammetry on a Cd anode. The photoaction spectra of these anodic thin films revealed an optical gap energy (1.7 eV) in good agreement with the value known for CdSe. Their luminescence response, however, suggested a high density of carrier recombination centers located {approximately}0.2 eV below the conduction band. X-ray photoelectron spectroscopy revealed that the anodic thin films were stoichiometric in composition. In situ examination of the material during thin film growth by cyclic photovoltammetry revealed anodic photoeffects at potentials just past the Cd corrosion wave. The growth kinetics in the passive region adhered to a direct logarithmic rate law, while a diffusion mechanism was seen to prevail in the transpassive regime.

  11. Synthesis, characterization and evaluation of the photocatalytic performance of Ag-CdMoO{sub 4} solar light driven plasmonic photocatalyst

    SciTech Connect

    Adhikari, Rajesh; Malla, Shova; Gyawali, Gobinda; Sekino, Tohru; Lee, Soo Wohn

    2013-09-01

    Graphical abstract: - Highlights: • Ag-CdMoO{sub 4} solar light driven photocatalyst was successfully synthesized. • Photocatalyst exhibited strong absorption in the visible region. • Photocatalytic activity was significantly enhanced. • Enhanced activity was caused by the SPR effect induced by Ag nanoparticles. - Abstract: Ag-CdMoO{sub 4} plasmonic photocatalyst was synthesized in ethanol/water mixture by photo assisted co-precipitation method at room temperature. As synthesized powders were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV–Vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET) surface area analyzer. Photocatalytic activity was evaluated by performing the degradation experiment over methylene blue (MB) and indigo carmine (IC) as model dyes under simulated solar light irradiation. The results revealed that the Ag-CdMoO{sub 4} showed the higher photocatalytic performance as compared to CdMoO{sub 4} nanoparticles. Dispersion of Ag nanoparticles over the surface of CdMoO{sub 4} nanoparticles causes the surface plasmon resonance (SPR) and enhances the broad absorption in the entire visible region of the solar spectrum. Hence, dispersion of Ag nanoparticles over CdMoO{sub 4} nanoparticles could be the better alternative to enhance the absorption of visible light by scheelite crystal family for effective photocatalysis.

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

    SciTech Connect

    Kayaalti, Zeliha Aliyev, Vugar; Soeylemezoglu, Tuelin

    2011-10-01

    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.

  13. Ag plasmonic nanostructures and a novel gel electrolyte in a high efficiency TiO2/CdS solar cell.

    PubMed

    Kumar, P Naresh; Deepa, Melepurath; Srivastava, Avanish Kumar

    2015-04-21

    A novel photoanode architecture with plasmonic silver (Ag) nanostructures embedded in titania (TiO2), which served as the wide band gap semiconducting support and CdS quantum dots (QDs), as light absorbers, is presented. Ag nanostructures were prepared by a polyol method and are comprised of clumps of nanorods, 15-35 nm wide, interspersed with globular nanoparticles and they were characterized by a face centered cubic lattice. Optimization of Ag nanostructures was achieved on the basis of a superior power conversion efficiency (PCE) obtained for the cell with a Ag/TiO2/CdS electrode encompassing a mixed morphology of Ag nano-rods and particles, relative to analogous cells with either Ag nanoparticles or Ag nanorods. Interfacial charge transfer kinetics was unraveled by fluorescence quenching and lifetime studies. Ag nanostructures improve the light harvesting ability of the TiO2/CdS photoanode via (a) plasmonic and scattering effects, which induce both near- and far-field enhancements which translate to higher photocurrent densities and (b) charging effects, whereby, photoexcited electron transfer from TiO2 to Ag is facilitated by Fermi level equilibration. Owing to the spectacular ability of Ag nanostructures to increase light absorption, a greatly increased PCE of 4.27% and a maximum external quantum efficiency of 55% (at 440 nm) was achieved for the cell based on Ag/TiO2/CdS, greater by 42 and 66%, respectively, compared to the TiO2/CdS based cell. In addition, the liquid S(2-) electrolyte was replaced by a S(2-) gel containing fumed silica, and the redox potential, conductivity and p-type conduction of the two were deduced to be comparable. Although the gel based cells showed diminished solar cell performances compared to their liquid counterparts, nonetheless, the Ag/TiO2/CdS electrode continued to outperform the TiO2/CdS electrode. Our studies demonstrate that Ag nanostructures effectively capture a significant chunk of the electromagnetic spectrum and aid QD

  14. Selective Facet Reactivity During Cation Exchange in Cadmium Sulfide Nanorods

    SciTech Connect

    Sadtler, Bryce; Demchenko, Denis; Zheng, Haimei; Hughes, Steven; Merkle, Maxwell; Dahmen, Ulrich; Wang, Lin-Wang; Alivisatos, A. Paul

    2008-12-18

    The partial transformation of ionic nanocrystals through cation exchange has been used to synthesize nanocrystal heterostructures. We demonstrate that the selectivity for cation exchange to take place at different facets of the nanocrystal plays an important role in determining the resulting morphology of the binary heterostructure. In the case of copper I (Cu+) cation exchange in cadmium sulfide (CdS) nanorods, the reaction starts preferentially at the ends of the nanorods such that copper sulfide (Cu2S) grows inwards from either end. The resulting morphology is very different from the striped pattern obtained in our previous studies of silver I (Ag+) exchange in CdS nanorods where non-selective nucleation of silver sulfide (Ag2S) occurs. From interface formation energies calculated for several models of epitaxialconnections between CdS and Cu2S or Ag2S, we infer the relative stability of each interface during the nucleation and growth of Cu2S or Ag2S within the CdS nanorods. The epitaxial connections of Cu2S to the end facets of CdS nanorods minimize the formation energy, making these interfaces stable throughout the exchange reaction. However, as the two end facets of wurtzite CdS nanorods are crystallographically nonequivalent, asymmetric heterostructures can be produced.

  15. Effect of adherent bacteria and bacterial extracellular polymers upon assimilation by Macoma balthica of sediment-bound Cd, Zn and Ag

    USGS Publications Warehouse

    Harvey, Ronald W.; Luoma, Samuel N.

    1985-01-01

    Effects of adherent bacteria and bacterial extracellular polymer (exopolymer) upon uptake of particle-bound Cd, Zn and Ag by the deposit-feeding clam Macoma balthica were studied in the laboratory. Amorphous iron oxyhydroxide and unaltered and alkaline-extracted sediments were used as model particulates in separate, controlled deposit-feeding experiments. In general, amounts of metal taken up from ingested particles varied dramatically with the nature of the particle surface. Ingestion of contaminated iron oxide particles did not contribute to overall uptake of Cd and Ag in feeding clams, but accounted for 89 to 99% of total Zn uptake. Exopolymer adsorbed on iron oxide particles caused an increase in the biological availability of particle-bound metals in the order Ag>Cd>Zn, whereas adherent bacteria up to 3.2 X 1011 g-1 had no effect upon amounts of metal taken up from ingested particulates. At the higher Cd and Ag concentrations employed (3.6 X 10-7M), feeding rates declined with increasing amounts of iron oxide-bound exopolymer, suggesting behavioral avoidance due to increased metal availability. Much of the Cd (57 %) taken up by clams feeding on unaltered estuarine sediments originated from particulates, even though particle/solute distribution of Cd (86%) was similar to that in experiments with iron oxide particles. Uptake of Cd from alkalineextracted sediments was insignificant, as it was from unamended iron oxide. However, addition of exopolymer (10 mgg-1 sediment) caused a restoration nn bioavailability of sediment-bound Cd.

  16. Surface enhanced Raman scattering, natural bond orbitals and Mulliken atomic charge distribution in the normal modes of diethyldithiocarbamate cadmium (II) complex, [Cd(DDTC)2

    NASA Astrophysics Data System (ADS)

    Téllez Soto, C. A.; Costa, A. C.; Versiane, O.; Lemma, T.; Machado, N. C. F.; Mondragón, M. A.; Martin, A. A.

    2015-07-01

    Theoretical and experimental bands have been assigned to the Fourier Transform Infrared (FT-IR) and FT-Raman spectra of the bis(diethyldithiocarbamate)Cd(II) complex, abbreviated as ([Cd(DDTC)2]). The calculations and spectral interpretation have been based on the DFT/B3LYP method, infrared and Raman second derivative spectra, and band deconvolution analysis to assist in the assignment of observed fundamentals. This study validated the unusual pseudo tetrahedral molecular structure formed around the Cd(II) cation. Surface-enhanced Raman scattering (SERS) was used to determine the interactions of the normal-modes of the diethyldithiocarbamate cadmium (II) complex on nano-structured silver surfaces. Natural bond orbital (NBO) analysis was also carried out to study the Cd(II) hybridization causing the pseudo tetrahedral geometry of the framework of the [Cd(DDTC)2] complex, and to confirm the charge transfer mechanisms through second order perturbation theory analysis of the Fox Matrix. In order to find out the electronic dispersion of the Mulliken atomic charges (MAC) in the normal modes, we calculated the MAC for each normal mode and correlated these values with the SERS effect. Experimental UV-Vis spectra were obtained and charge transfer bands were assigned. Good agreement between the calculated and experimental values for the vibrational and UV-Vis spectra was obtained.

  17. Al-Cd Alloy Formation by Aluminum Underpotential Deposition from AlCl3+NaCl Melts on Cadmium Substrate

    NASA Astrophysics Data System (ADS)

    Jovićević, Niko; Cvetković, Vesna S.; Kamberović, Željko J.; Jovićević, Jovan N.

    2013-02-01

    Aluminum was incorporated into a polycrystalline cadmium electrode surface by underpotential deposition from equimolar AlCl3+ NaCl melt at 473 K, 523 K, and 573 K (200 °C, 250 °C, and 300 °C). The process was studied by linear sweep voltammetry and potentiostatic deposition/galvanostatic striping. The deposits were characterized X-ray diffraction (XRD), Auger electron spectroscopy (AES), and electron probe microanalyzer (EPMA). The electrochemical measurements showed evidence of Cd-Al alloys being formed but they could not be identified. The growth kinetics of the Cd-Al layers of various proportion and depths that depended on temperature and deposition time were described.

  18. Numerical calculation of plasmonic field absorption enhancement in CdSe-quantum dot sensitized ZnO nanorods by Ag nanoparticle periodic arrays

    NASA Astrophysics Data System (ADS)

    Kohnehpoushi, Saman; Eskandari, Mehdi; Nejand, Bahram Abdollahi; Ahmadi, Vahid

    2016-12-01

    Plasmonic field absorption enhancement (PFAE) of Ag nanoparticles (Ag NPs) periodic arrays in CdSe-quantum dot (QD) sensitized ZnO nanorods was numerically investigated by the three-dimensional finite difference time domain (FDTD). The Ag NPs with spherical morphology were found to have an optimum PFAE compared to other Ag NP morphologies such as cubic and pyramidal. The results also showed that PFAE intensity in CdSe-QD-sensitized ZnO nanorods is increased with the reduction of Ag NP diameter until 10 nm and decreases thereafter. Moreover, the optimum density of spherical Ag NPs for optimum PFAE was observed as 20%. PFAE in CdSe-QD-sensitized ZnO nanorods is improved with increasing space between ZnO nanorods until 180 nm and reduces thereafter. Finally, the results showed that PFAE of Ag NPs for the high distance between ZnO nanorods is dependent on radiation angle; while for the low distance between ZnO nanorods it is free of radiation angle.

  19. Bright white-light emission from Ag/SiO2/CdS-ZnS core/shell/shell plasmon couplers

    NASA Astrophysics Data System (ADS)

    Liao, Chen; Tang, Luping; Gao, Xiaoqin; Xu, Ruilin; Zhang, Huichao; Yu, Yongya; Lu, Changgui; Cui, Yiping; Zhang, Jiayu

    2015-12-01

    Well-defined plasmon couplers (PCs) that comprise a Ag core overcoated with a SiO2 shell with controlled thickness, followed by a monolayer of CdS-ZnS core-shell quantum dots (QDs) were synthesized to modify the emission from trap-rich CdS-ZnS QDs by adjusting the distance between the QDs and Ag nanoparticles (NPs). When the thickness of the SiO2 shell was 10 nm, because the shell could effectively suppress the non-radiative energy transfer from the semiconductor QDs to the metal NPs and the localized surface plasmon resonance (LSPR) of the Ag NPs spectrally matched the emission peak of the CdS-ZnS QDs to bring about strong plasmon coupling, optimum enhancements of the surface state emission (SSE) (17 times) and band-edge emission (BEE) (4 times) were simultaneously realized and the SSE to BEE intensity ratio was increased to 55%. As a result, a bright white-light source with 1931 Commission Internationale d'Eclairage (CIE) chromaticity coordinates of (0.32, 0.34) was realized by the superposition of the two emissions. The experimental results from Ag/SiO2/CdSe-ZnS and the Ag/SiO2/CdS:Mn-ZnS core/shell/shell PCs indicated that suppressing the non-radiative decay rate (knr) was the underlying mechanism for plasmon coupling fluorescence enhancement.

  20. Zinc Fertilization Plus Liming to Reduce Cadmium Uptake by Romaine Lettuce on Cd-Mineralized Lockwood Soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lockwood shaly loam (Pachic Argixerolls) and similar Cd mineralized soils derived from marine shale in California contain higher Cd levels and higher Cd:Zn ratios than uncontaminated US soils, and produce leafy vegetables with considerably higher Cd than is normal for US lettuce. Previous work by B...

  1. CdS-Nanowires Flexible Photo-detector with Ag-Nanowires Electrode Based on Non-transfer Process

    NASA Astrophysics Data System (ADS)

    Pei, Yanli; Pei, Ruihan; Liang, Xiaoci; Wang, Yuhao; Liu, Ling; Chen, Haibiao; Liang, Jun

    2016-02-01

    In this study, UV-visible flexible resistivity-type photo-detectors were demonstrated with CdS-nanowires (NWs) percolation network channel and Ag-NWs percolation network electrode. The devices were fabricated on Mixed Cellulose Esters (MCE) membrane using a lithographic filtration method combined with a facile non-transfer process. The photo-detectors demonstrated strong adhesion, fast response time, fast decay time, and high photo sensitivity. The high performance could be attributed to the high quality single crystalline CdS-NWs, encapsulation of NWs in MCE matrix and excellent interconnection of the NWs. Furthermore, the sensing performance was maintained even the device was bent at an angle of 90°. This research may pave the way for the facile fabrication of flexible photo-detectors with high performances.

  2. Cd - Np (Cadmium - Neptunium)

    NASA Astrophysics Data System (ADS)

    Predel, B.

    This document is part of Volume 12 Phase Equilibria, Crystallographic and Thermodynamic Data of Binary Alloys', Subvolume B 'B - Ba … Cu - Zr, Supplement to Subvolumes IV/5B, IV/5C and IV/5D', of Landolt-Börnstein - Group IV 'Physical Chemistry'.

  3. A study on dependence of the structural, optical and electrical properties of cadmium lead sulphide thin films on Cd/Pb ratio

    SciTech Connect

    Nair, Sinitha B. E-mail: anithakklm@gmail.com; Abraham, Anitha E-mail: anithakklm@gmail.com; Philip, Rachel Reena; Pradeep, B.; Shripathi, T. E-mail: vganesancsr@gmail.com; Ganesan, V. E-mail: vganesancsr@gmail.com

    2014-10-15

    Cadmium Lead Sulphide thin films with systematic variation in Cd/Pb ratio are prepared at 333K by CBD, adjusting the reagent-molarity, deposition time and pH. XRD exhibits crystalline-amorphous transition as Cd% exceeds Pb%. AFM shows agglomeration of crystallites of size ∼50±5 nm. EDAX assess the composition whereas XPS ascertains the ternary formation, with binding energies of Pb4f{sub 7/2} and 4f{sub 5/2}, Cd3d{sub 5/2} and 3d{sub 3/2} and S2p at 137.03, 141.606, 404.667, 412.133 and 160.218 eV respectively. The optical absorption spectra reveal the variance in the direct allowed band gaps, from 1.57eV to 2.42 eV as Cd/Pb ratio increases from 0.2 to 2.7, suggesting possibility of band gap engineering in the n-type films.

  4. Modulating resonance modes and Q value of a CdS nanowire cavity by single Ag nanoparticles.

    PubMed

    Zhang, Qing; Shan, Xin-Yan; Feng, Xiao; Wang, Chun-Xiao; Wang, Qu-Quan; Jia, Jin-Feng; Xue, Qi-Kun

    2011-10-12

    Semiconductor nanowire (NW) cavities with tailorable optical modes have been used to develop nanoscale oscillators and amplifiers in microlasers, sensors, and single photon emitters. The resonance modes of NW could be tuned by different boundary conditions. However, continuously and reversibly adjusting resonance modes and improving Q-factor of the cavity remain a great challenge. We report a method to modulate resonance modes continuously and reversibly and improve Q-factor based on surface plasmon-exciton interaction. By placing single Ag nanoparticle (NP) nearby a CdS NW, we show that the wavelength and relative intensity of the resonance modes in the NW cavity can systematically be tuned by adjusting the relative position of the Ag NP. We further demonstrate that a 56% enhancement of Q-factor and an equivalent π-phase shift of the resonance modes can be achieved when the Ag NP is located near the NW end. This hybrid cavity has potential applications in active plasmonic and photonic nanodevices.

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

    PubMed

    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.

  6. Plasmon enhanced CdS-quantum dot sensitized solar cell using ZnO nanorods array deposited with Ag nanoparticles as photoanode

    NASA Astrophysics Data System (ADS)

    Eskandari, M.; Ahmadi, V.; Yousefi rad, M.; Kohnehpoushi, S.

    2015-04-01

    CdS-quantum dot sensitized solar cell using ZnO nanorods (ZnO NRs) array deposited with Ag nanoparticles (Ag NPs) as photoanode was fabricated. Light absorption effect of Ag NPs on improvement of the cell performance was investigated. Performance improvement of metal nanoparticles (MNPs) was controlled by the structure design and architecture. Different decorations and densities of Ag NPs were utilized on the photoanode. Results showed that using 5% Ag NPs in the photoanode results in the increased efficiency, fill factor, and circuit current density from 0.28% to 0.60%, 0.22 to 0.29, and 2.18 mA/cm2 to 3.25 mA/cm2, respectively. Also, incident photon-to-current efficiencies (IPCE) results showed that cell performance improvement is related to enhanced absorption in the photoanode, which is because of the surface plasmonic resonance and light scattering of Ag NPs in the photoanode. Measurements of electrochemical impedance spectroscopy revealed that hole transfer kinetics increases with introduction of Ag NPs into photoanode. Also, it is shown that chemical capacitance increases with introduction of Ag NPs. Such increase can be attributed to the surface palsmonic resonance of Ag NPs which leads to absorption of more light in the photoanode and generation of more photoelectron in the photoanode.

  7. Enhanced DSSCs efficiency via Cooperate co-absorbance (CdS QDs) and plasmonic core-shell nanoparticle (Ag@PVP)

    NASA Astrophysics Data System (ADS)

    Amiri, Omid; Salavati-Niasari, Masoud; Bagheri, Samira; Yousefi, Amin Termeh

    2016-05-01

    This paper describes cooperate the co-absorbance (CdS QDs) and the plasmonic core-shell nanoparticles (Ag@PVP) of dye synthesized solar cells in which CdS QDs and Ag@PVP are incorporated into the TiO2 layer. Cooperative nanoparticles show superior behavior on enhancing light absorption in comparison with reference cells. Cooperated DSSC exhibits the best performance with the power conversion efficiency of 7.64% which is superior to that of the free–modified DSSC with the PCE of 5%. Detailed studies offer an effective approach to enhance the efficiency of dye synthesized solar cells.

  8. Enhanced DSSCs efficiency via Cooperate co-absorbance (CdS QDs) and plasmonic core-shell nanoparticle (Ag@PVP)

    PubMed Central

    Amiri, Omid; Salavati-Niasari, Masoud; Bagheri, Samira; Yousefi, Amin Termeh

    2016-01-01

    This paper describes cooperate the co-absorbance (CdS QDs) and the plasmonic core-shell nanoparticles (Ag@PVP) of dye synthesized solar cells in which CdS QDs and Ag@PVP are incorporated into the TiO2 layer. Cooperative nanoparticles show superior behavior on enhancing light absorption in comparison with reference cells. Cooperated DSSC exhibits the best performance with the power conversion efficiency of 7.64% which is superior to that of the free–modified DSSC with the PCE of 5%. Detailed studies offer an effective approach to enhance the efficiency of dye synthesized solar cells. PMID:27143126

  9. Fabrication and characterization of ZnO@CdS core-shell nanostructure using acetate precursors: XRD, FESEM, DRS, FTIR studies and effects of cadmium ion concentration on band gap

    NASA Astrophysics Data System (ADS)

    Habibi, Mohammad Hossein; Rahmati, Mohammad Hossein

    2014-12-01

    ZnO@CdS core-shell nano-structure has been synthesized using zinc acetate dihydrate, and cadmium acetate dihydrate as simple precursors in a water-ethanol matrix without using any surfactant, ligand or chelating agents. The effect of different concentrations of cadmium acetate and sodium sulfide on optical and electronic properties of ZnO@CdS core-shell was investigated. The morphology and structure of the ZnO@CdS core-shell nano-structures have been confirmed by field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) measurements. The results showed that the ZnO@CdS core-shell nano-structure is mixed cubic and hexagonal structures. FESEM results showed the mono-dispersed and uniform size of 39 nm. Optical properties were studied by UV-visible diffuse reflectance spectroscopy (DRS) technique and the results showed that band gaps of ZnO@CdS core-shell nanocomposites were red shifted by increasing the cadmium concentration. FTIR spectrum of ZnO@CdS core-shell nano-structure showed a band at 482 cm-1 correlated to Znsbnd O bond and a band at 630 cm-1 due to the stretching frequency of Cdsbnd S bond.

  10. Thermo-optical characterization of cadmium selenide/zinc sulfide (CdSe/ZnS) quantum dots embedded in biocompatible materials.

    PubMed

    Pilla, Viviane; Alves, Leandro P; Iwazaki, Adalberto N; Andrade, Acácio A; Antunes, Andrea; Munin, Egberto

    2013-09-01

    Cadmium selenide/zinc sulfide (CdSe/ZnS) core-shell quantum dots (QDs) embedded in biocompatible materials were thermally and optically characterized with a thermal lens (TL) technique. Transient TL measurements were performed with a mode-mismatched, dual-beam (excitation and probe) configuration. A thermo-optical study of the CdSe/ZnS QDs was performed for different core diameters (3.5, 4.0, 5.2, and 6.6 nm) in aqueous solution and synthetic saliva, and three different core diameters (2.4, 2.9, and 4.1 nm) embedded in restorative dental resin (0.025% by mass). The thermal diffusivity results are characteristic of the biocompatible matrices. The radiative quantum efficiencies for aqueous solution and biofluid materials are dependent on the core size of the CdSe/ZnS core-shell QDs. The results obtained from the fluorescence spectral measurements for the biocompatible materials support the TL results.

  11. An ultrasensitive label-free electrochemical immunosensor based on signal amplification strategy of multifunctional magnetic graphene loaded with cadmium ions

    NASA Astrophysics Data System (ADS)

    Li, Faying; Li, Yueyun; Dong, Yunhui; Jiang, Liping; Wang, Ping; Liu, Qing; Liu, Hui; Wei, Qin

    2016-02-01

    Herein, a novel and ultrasensitive label-free electrochemical immunosensor was proposed for quantitative detection of human Immunoglobulin G (IgG). The amino functionalized magnetic graphenes nanocomposites (NH2-GS-Fe3O4) were prepared to bond gold and silver core-shell nanoparticles (Au@Ag NPs) by constructing stable Au-N and Ag-N bond between Au@Ag NPs and -NH2. Subsequently, the Au@Ag/GS-Fe3O4 was applied to absorb cadmium ion (Cd2+) due to the large surface area, high conductivity and exceptional adsorption capability. The functional nanocomposites of gold and silver core-shell magnetic graphene loaded with cadmium ion (Au@Ag/GS-Fe3O4/Cd2+) can not only increase the electrocatalytic activity towards hydrogen peroxide (H2O2) but also improve the effective immobilization of antibodies because of synergistic effect presented in Au@Ag/GS-Fe3O4/Cd2+, which greatly extended the scope of detection. Under the optimal conditions, the proposed immunosensor was used for the detection of IgG with good linear relation in the range from 5 fg/mL to 50 ng/mL with a low detection limit of 2 fg/mL (S/N = 3). Furthermore, the proposed immunosensor showed high sensitivity, special selectivity and long-term stability, which had promising application in bioassay analysis.

  12. An ultrasensitive label-free electrochemical immunosensor based on signal amplification strategy of multifunctional magnetic graphene loaded with cadmium ions

    PubMed Central

    Li, Faying; Li, Yueyun; Dong, Yunhui; Jiang, Liping; Wang, Ping; Liu, Qing; Liu, Hui; Wei, Qin

    2016-01-01

    Herein, a novel and ultrasensitive label-free electrochemical immunosensor was proposed for quantitative detection of human Immunoglobulin G (IgG). The amino functionalized magnetic graphenes nanocomposites (NH2-GS-Fe3O4) were prepared to bond gold and silver core-shell nanoparticles (Au@Ag NPs) by constructing stable Au-N and Ag-N bond between Au@Ag NPs and -NH2. Subsequently, the Au@Ag/GS-Fe3O4 was applied to absorb cadmium ion (Cd2+) due to the large surface area, high conductivity and exceptional adsorption capability. The functional nanocomposites of gold and silver core-shell magnetic graphene loaded with cadmium ion (Au@Ag/GS-Fe3O4/Cd2+) can not only increase the electrocatalytic activity towards hydrogen peroxide (H2O2) but also improve the effective immobilization of antibodies because of synergistic effect presented in Au@Ag/GS-Fe3O4/Cd2+, which greatly extended the scope of detection. Under the optimal conditions, the proposed immunosensor was used for the detection of IgG with good linear relation in the range from 5 fg/mL to 50 ng/mL with a low detection limit of 2 fg/mL (S/N = 3). Furthermore, the proposed immunosensor showed high sensitivity, special selectivity and long-term stability, which had promising application in bioassay analysis. PMID:26880596

  13. Cadmium-catalyzed surface growth of single-walled carbon nanotubes with high efficiency

    SciTech Connect

    Qian, Yong; Lu, Shunbao; Gao, Fenglei

    2011-06-15

    Graphical abstract: The Cd nanocatalysts, prepared using a diblock copolymer templating method, were uniformly spaced over a large deposition area with an average diameter of 1.9 nm and narrow size distribution. By using the normal-heating method, high density SWNTs can be generated. Research highlights: {yields} We demonstrate that cadmium (Cd) can catalyze the growth of SWNTs with high efficiency. {yields} The PVP capped-Cd nanocatalysts were uniformly spaced over a large deposition area with an average diameter of 1.9 nm. {yields} By using the normal-heating and fast-heating method, random and horizontally aligned arrays of SWNTs can be generated. {yields} The high percentage of SWNTs with Ag deposition from Cd indicates that the SWNTs have better conductivity and structural uniformity. -- Abstract: We demonstrate that cadmium (Cd) can catalyze the growth of single-walled carbon nanotubes (SWNTs) with high efficiency. The Cd nanocatalysts, prepared using a diblock copolymer templating method, were uniformly spaced over a large deposition area with an average diameter of 1.9 nm and narrow size distribution. By using the normal-heating and fast-heating method, random and horizontally aligned arrays of SWNTs can be generated. The density of the SWNTs can be altered by the chemical vapor deposition conditions. The morphology and microstructure of the SWNTs characterized by scanning electron microscopy, Raman spectroscopy, atomic force microscopy, and high-resolution transmission electron microscopy revealed that the grown nanotubes do not have carbonaceous particles and have good crystallinity. In addition, after careful check with superlong nanotubes 735 out of 790 nanotubes were found to be deposited with Ag (93%) and only 7% SWNTs without Ag deposition. While for superlong SWNT arrays from Fe, 32% long SWNTs without Ag deposition was found, the high percentage of SWNTs with Ag deposition from Cd indicates that the SWNTs have better conductivity and better

  14. Thermally induced effect on sub-band gap absorption in Ag doped CdSe thin films

    NASA Astrophysics Data System (ADS)

    Kaur, Jagdish; Sharma, Kriti; Bharti, Shivani; Tripathi, S. K.

    2015-05-01

    Thin films of Ag doped CdSe have been prepared by thermal evaporation using inert gas condensation (IGC) method taking Argon as inert gas. The prepared thin films are annealed at 363 K for one hour. The sub-band gap absorption spectra in the as deposited and annealed thin films have been studied using constant photocurrent method (CPM). The absorption coefficient in the sub-band gap region is described by an Urbach tail in both as deposited and annealed thin films. The value of Urbach energy and number density of trap states have been calculated from the absorption coefficient in the sub-band gap region which have been found to increase after annealing treatment indicating increase in disorderness in the lattice. The energy distribution of the occupied density of states below Fermi level has also been studied using derivative procedure of absorption coefficient.

  15. Cadmium resistance in Drosophila: a small cadmium binding substance

    SciTech Connect

    Jacobson, K.B.; Williams, M.W.; Richter, L.J.; Holt, S.E.; Hook, G.J.; Knoop, S.M.; Sloop, F.V.; Faust, J.B.

    1985-01-01

    A small cadmium-binding substance (CdBS) has been observed in adult Drosophila melanogaster that were raised for their entire growth cycle on a diet that contained 0.15 mM CdCl/sub 2/. Induction of CdBS was observed in strains that differed widely in their sensitivity of CdCl/sub 2/. This report describes the induction of CdBS and some of its characteristics. 17 refs., 4 figs., 1 tab.

  16. New five coordinated supramolecular structured cadmium complex as precursor for CdO nanoparticles: Synthesis, crystal structure, theoretical and 3D Hirshfeld surface analyses

    NASA Astrophysics Data System (ADS)

    Ghanbari Niyaky, S.; Montazerozohori, M.; Masoudiasl, A.; White, J. M.

    2017-03-01

    In this paper, a combined experimental and theoretical study on a new CdLBr2 complex (L = N1-(2-bromobenzylidene)-N2-(2-((E)-(2-bromobenzylidene) amino)ethyl) ethane-1,2-diamine) synthesized via template method, is described. The crystal structure analysis of the complex indicates that, the Cd(II) ion is centered in a distorted square pyramidal space constructed by three iminic nitrogens of the ligand as well as two bromide anions. More analysis of crystal packing proposed a supramolecular structure stabilized by some non-covalent interactions such as Br⋯Br and Xsbnd H⋯Br (X = N and C) in solid state. Furthermore, 3D Hirshfeld surface analyses and DFT studies were applied for theoretical investigation of the complexes. Theoretical achievements were found in a good agreement with respect to the experimental data. To evaluate the nature of bonding and the strength of the intra and inter-molecular interactions a natural bond orbital (NBO) analysis on the complex structure was performed. Time dependent density functional theory (TD-DFT) was also applied to predict the electronic spectral data of the complex as compared with the experimental ones. CdLBr2 complex as nano-structure compound was also prepared under ultrasonic conditions and characterized by scanning electron microscopy (SEM) and X-ray powder diffraction (XRPD). Finally, it was found that the cadmium complex can be used as a suitable precursor for preparation of CdO nanoparticles via calcination process at 600 °C under air atmosphere.

  17. Fluorescence Properties of Fe2+- and Co2+-doped Hosts of CdMnTe Compositions as Potential Mid-Infrared Laser Materials

    DTIC Science & Technology

    2011-09-01

    on Cr- and Fe-doped binary ZnSe, zinc sulfide (ZnS), cadmium selenide (CdSe), cadmium sulfide (CdS), zinc telluride (ZnTe), or ternary cadmium ...manganese telluride (CdMnTe or CMT), cadmium zinc telluride (CdZnTe), and zinc sulfur selenide (ZnSSe) chalcogenide crystals (1). Among the TM ions, Cr2... cadmium magnesium telluride CdS cadmium sulfide CdSe cadmium selenide CdTe cadmium telluride CdZnTe cadmium zinc telluride Co2+ divalent

  18. Improving the efficiency of cadmium sulfide-sensitized titanium dioxide/indium tin oxide glass photoelectrodes using silver sulfide as an energy barrier layer and a light absorber

    NASA Astrophysics Data System (ADS)

    Chen, Chong; Zhai, Yong; Li, Chunxi; Li, Fumin

    2014-11-01

    Cadmium sulfide (CdS) and silver sulfide (Ag2S) nanocrystals are deposited on the titanium dioxide (TiO2) nanocrystalline film on indium tin oxide (ITO) substrate to prepare CdS/Ag2S/TiO2/ITO photoelectrodes through a new method known as the molecular precursor decomposition method. The Ag2S is interposed between the TiO2 nanocrystal film and CdS nanocrystals as an energy barrier layer and a light absorber. As a consequence, the energy conversion efficiency of the CdS/Ag2S/TiO2/ITO electrodes is significantly improved. Under AM 1.5 G sunlight irradiation, the maximum efficiency achieved for the CdS(4)/Ag2S/TiO2/ITO electrode is 3.46%, corresponding to an increase of about 150% as compared to the CdS(4)/TiO2/ITO electrode without the Ag2S layer. Our experimental results show that the improved efficiency is mainly due to the formation of Ag2S layer that may increase the light absorbance and reduce the recombination of photogenerated electrons with redox ions from the electrolyte.

  19. Improving the efficiency of cadmium sulfide-sensitized titanium dioxide/indium tin oxide glass photoelectrodes using silver sulfide as an energy barrier layer and a light absorber

    PubMed Central

    2014-01-01

    Cadmium sulfide (CdS) and silver sulfide (Ag2S) nanocrystals are deposited on the titanium dioxide (TiO2) nanocrystalline film on indium tin oxide (ITO) substrate to prepare CdS/Ag2S/TiO2/ITO photoelectrodes through a new method known as the molecular precursor decomposition method. The Ag2S is interposed between the TiO2 nanocrystal film and CdS nanocrystals as an energy barrier layer and a light absorber. As a consequence, the energy conversion efficiency of the CdS/Ag2S/TiO2/ITO electrodes is significantly improved. Under AM 1.5 G sunlight irradiation, the maximum efficiency achieved for the CdS(4)/Ag2S/TiO2/ITO electrode is 3.46%, corresponding to an increase of about 150% as compared to the CdS(4)/TiO2/ITO electrode without the Ag2S layer. Our experimental results show that the improved efficiency is mainly due to the formation of Ag2S layer that may increase the light absorbance and reduce the recombination of photogenerated electrons with redox ions from the electrolyte. PMID:25411566

  20. Improving the efficiency of cadmium sulfide-sensitized titanium dioxide/indium tin oxide glass photoelectrodes using silver sulfide as an energy barrier layer and a light absorber.

    PubMed

    Chen, Chong; Zhai, Yong; Li, Chunxi; Li, Fumin

    2014-01-01

    Cadmium sulfide (CdS) and silver sulfide (Ag2S) nanocrystals are deposited on the titanium dioxide (TiO2) nanocrystalline film on indium tin oxide (ITO) substrate to prepare CdS/Ag2S/TiO2/ITO photoelectrodes through a new method known as the molecular precursor decomposition method. The Ag2S is interposed between the TiO2 nanocrystal film and CdS nanocrystals as an energy barrier layer and a light absorber. As a consequence, the energy conversion efficiency of the CdS/Ag2S/TiO2/ITO electrodes is significantly improved. Under AM 1.5 G sunlight irradiation, the maximum efficiency achieved for the CdS(4)/Ag2S/TiO2/ITO electrode is 3.46%, corresponding to an increase of about 150% as compared to the CdS(4)/TiO2/ITO electrode without the Ag2S layer. Our experimental results show that the improved efficiency is mainly due to the formation of Ag2S layer that may increase the light absorbance and reduce the recombination of photogenerated electrons with redox ions from the electrolyte.

  1. Determination and speciation of cadmium in microcosms with Bunodosoma caissarum and Perna perna using isotopically enriched (116)Cd.

    PubMed

    Rizzini Ansari, Nafisa; Fernández Iglesias, Nerea; Cordeiro, Renato Campello; Fernandez, Marcos Antônio; Bettmer, Jörg

    2017-02-15

    The study of the uptake and distribution of elements in marine environments is of great interest for understanding their pathways and accumulation. Here, we investigated in laboratory experiments the accumulation behavior of Cd in the sea anemone Bunodosoma caissarum and the mussel Perna perna. Specimens were incubated with isotopically enriched (116)Cd in aquariums. Cd concentrations in the seawater and in the tissues of B. caissarum and P. perna were followed by inductively coupled plasma-mass spectrometry (ICP-MS) by means of isotope dilution analysis. Bioconcentration factors for B. caissarum and P. perna exposed to 0.9μg·L(-1) of (116)Cd were determined to be 80.5 and 850, respectively. P. perna specimens exposed to 4.5μg·L(-1) of (116)Cd reached 530. Cytosolic proteins associated with Cd from the tissues were extracted and further analyzed by size-exclusion chromatography coupled to ICP-MS. Cd accumulation could be detected in both organisms ranging from high-molecular to low-molecular species.

  2. Cadmium stannate selective optical films for solar energy applications

    NASA Technical Reports Server (NTRS)

    Haacke, G.

    1975-01-01

    Efforts concentrated on reducing the electrical sheet resistance of sputtered cadmium stannate films, installing and testing equipment for spray coating experiments, and sputter deposition of thin cadmium sulfide layers onto cadmium stannate electrodes. In addition, single crystal silicon wafers were coated with cadmium stannate. Work also continued on the development of the backwall CdS solar cell.

  3. Cadmium migration in aerospace nickel cadmium cells

    NASA Technical Reports Server (NTRS)

    Mcdermott, P. P.

    1976-01-01

    The effects of temperature, the nature of separator material, charge and discharge, carbonate contamination, and the mode of storage are studied with respect to the migration of active material from the negative toward the positive plate. A theoretical model is proposed which takes into account the solubility of cadmium in various concentrations of hydroxide and carbonate at different temperatures, the generation of the cadmiate ion, Cd(OH)3(-), during discharge, the migration of the cadmiate ion and particulate Cd(OH)2 due to electrophoretic effects and the movement of electrolyte in and out of the negative plate and, finally, the recrystallization of cadmiate ion in the separator as Cd(OH)2. Application of the theoretical model to observations of cadmium migration in cycled cells is also discussed.

  4. Radiation Characterization Summary: ACRR Cadmium-Polyethylene (CdPoly) Bucket Located in the Central Cavity on the 32-Inch Pedestal at the Core Centerline

    SciTech Connect

    Parma, Edward J.; Naranjo, Gerald E.; Kaiser, Krista Irene; Arnold, James F.; Lippert, Lance L.; Clovis, Ralph D.; Martin, Lonnie E.; Quirk, Thomas J.; Vehar, David W.

    2016-10-01

    This document presents the facility-recommended characterization of the neutron, prompt gamma-ray, and delayed gamma-ray radiation fields in the Annular Core Research Reactor (ACRR) for the cadmium-polyethylene (CdPoly) bucket in the central cavity on the 32-inch pedestal at the core centerline. The designation for this environment is ACRR-CdPoly-CC-32-cl. The neutron, prompt gamma-ray, and delayed gamma-ray energy spectra, uncertainties, and covariance matrices are presented as well as radial and axial neutron and gamma-ray fluence profiles within the experiment area of the bucket. Recommended constants are given to facilitate the conversion of various dosimetry readings into radiation metrics desired by experimenters. Representative pulse operations are presented with conversion examples. Acknowledgements The authors wish to thank the Annular Core Research Reactor staff and the Radiation Metrology Laboratory staff for their support of this work. Also thanks to Drew Tonigan for helping field the activation experiments in ACRR, David Samuel for helping to finalize the drawings and get the parts fabricated, and Elliot Pelfrey for preparing the active dosimetry plots.

  5. Physiological characterization of Chlamydomonas reinhardtii acclimated to chronic stress induced by Ag, Cd, Cr, Cu and Hg ions.

    PubMed

    Nowicka, Beatrycze; Pluciński, Bartosz; Kuczyńska, Paulina; Kruk, Jerzy

    2016-08-01

    Acclimation to heavy metal-induced stress is a complex phenomenon. Among the mechanisms of heavy metal toxicity, an important one is the ability to induce oxidative stress, so that the antioxidant response is crucial for providing tolerance to heavy metal ions. The effect of chronic stress induced by ions of five heavy metals, Ag, Cu, Cr (redox-active metals) Cd, Hg (nonredox-active metals) on the green microalga Chlamydomonas reinhardtii was examined at two levels - the biochemical (content of photosynthetic pigments and prenyllipid antioxidants, lipid peroxidation) and the physiological (growth rate, photosynthesis and respiration rates, induction of nonphotochemical quenching of chlorophyll fluorescence). The expression of the genes which encode the enzymes participating in the detoxification of reactive oxygen species (APX1, CAT1, FSD1, MSD1) was measured. The other gene measured was one required for plastoquinone and α-tocopherol biosynthesis (VTE3). The application of heavy metal ions partly inhibited growth and biosynthesis of chlorophyll. The growth inhibition was accompanied by enhanced lipid peroxidation. An increase in the content of prenyllipid antioxidants was observed in cultures exposed to Cr2O7(2-), Cd(2+) (α- and γ-tocopherol and plastoquinone) and Cu(2+) (only tocopherols). The induction of nonphotochemical quenching was enhanced in cultures exposed to Cu(2+), Cr2O7(2-) and Cd(2+), as compared to the control. Chronic heavy metal-induced stress led to changes in gene expression dependent on the type and concentration of heavy metal ions. The up-regulation of antioxidant enzymes was usually accompanied by the up-regulation of the VTE3 gene.

  6. Modeling of axial vibrational control technique for CdTe VGF crystal growth under controlled cadmium partial pressure

    NASA Astrophysics Data System (ADS)

    Avetissov, I.; Kostikov, V.; Meshkov, V.; Sukhanova, E.; Grishechkin, M.; Belov, S.; Sadovskiy, A.

    2014-01-01

    A VGF growth setup assisted by axial vibrations of baffle submerged into CdTe melt with controlled Cd partial pressure was designed. An influence of baffle shape on flow velocity map, temperature distribution in CdTe melt and interface shape of growing crystal was analyzed by numerical simulation and physical modeling. To produce the desirable shape of crystal melt interface we slant under different angles vertical generatrix in a cylindrical disk and made chasing on faceplates of a disk. It was ascertained that a disk with conical generatrix formed more intensive convective flows from a faceplate with larger diameter. It was shown that at CdTe VGF crystal growth rate about 10 mm/h application of AVC technique made it possible to produce convex interface for 2 in. crystal diameter.

  7. γδ T cells support gut Ag-reactive colitogenic effector T-cell generation by enhancing Ag presentation by CD11b(+) DCs in the mesenteric LN.

    PubMed

    Do, Jeongsu; Visperas, Anabelle; Freeman, Michael L; Jang, Eunjung; Kim, Sohee; Malissen, Bernard; Min, Booki

    2016-02-01

    T cells expressing the γδ TCR are dominant T-cell subsets in the intestinal immune system. We previously demonstrated that γδ T cells play important roles in augmenting Th17-type colitogenic immune responses in a T-cell-induced colitic inflammation model. However, its underlying mechanism remains poorly understood. In this study, an in vitro coculture system using effector T cells enriched in gut Ag-reactive cells was employed as a readout tool to search for gut Ag presenting APCs. We found that the presence of γδ T cells dramatically enhances gut Ag presentation within the mLN in mice. Gut Ag presentation by CD11b(+) DC subsets was particularly controlled by γδ T cells. Interestingly, γδ T-cell entry to the lymph nodes was essential to improve the Ag presentation. Therefore, our results highlight that γδ T cells play a previously unrecognized role to support colitogenic immunity by regulating gut Ag presentation in the draining LN.

  8. Application of hybrid SiO2-coated CdTe nanocrystals for sensitive sensing of Cu2+ and Ag+ ions.

    PubMed

    Cao, Yongqiang; Zhang, Aiyu; Ma, Qian; Liu, Ning; Yang, Ping

    2013-01-01

    A new ion sensor based on hybrid SiO2 -coated CdTe nanocrystals (NCs) was prepared and applied for sensitive sensing of Cu(2+) and Ag(+) for the selective quenching of photoluminescence (PL) of NCs in the presence of ions. As shown by ion detection experiments conducted in pure water rather than buffer solution, PL responses of NCs were linearly proportional to concentrations of Cu(2+) and Ag(+) ions < 3 and 7 uM, respectively. Much lower detection limits of 42.37 nM for Cu(2+) and 39.40 nM for Ag(+) were also observed. In addition, the NC quenching mechanism was discussed in terms of the characterization of static and transient optical spectra. The transfer and trapping of photoinduced charges in NCs by surface energy levels of CuS and Ag2 S clusters as well as surface defects generated by the exchange of Cu(2+) and Ag(+) ions with Cd(2+) ion in NCs, resulted in PL quenching and other optical spectra changes, including steady-state absorption and transient PL spectra. It is our hope that these results will be helpful in the future preparation of new ion sensors.

  9. The suitability of air cooled helium cadmium (HeCd) lasers for two color analysis and sorting of human chromosomes

    SciTech Connect

    Snow, C.; Cram, L.S. Los Alamos National Lab., NM )

    1993-01-01

    Commonly available HeCd lasers operate at wavelengths of 325 and 442 nm, close to the published absorption maxima of the Hoechst and chromomycin dyes used for vibariate flow karyotype analyses. Although bivariate chromosome analysis has heretofore required the use of water cooled argon ion lasers operating at hundreds of milliwatts, the HeCd lasers usually produce about one tenth this power (30 mW at 325 nm and 50 mW at 442 nm). Recently a sorting quartz flow cell design has been introduced which allows improved sensitivity compared to jet-in-air operation. The goal of this study was to determine if such an improvement in sensitivity would allow the use of HeCd air cooled lasers for bivariate flow karyotype analysis. They examined the resolution of chromosomes isolated from the human fibroblast cell line GM130 as well as a hamster-human somatic cell hybrid (Q826-20) containing a single human chromosome (No. 5). Resolution with the HeCd lasers was comparable to that obtained using water cooled argon ion lasers. Data are shown illustrating the results obtained with the two different excitation configurations. The advantages of using 442 nm exciation for chromomycin, compared to 457 nm are illustrated. In conclusion, small air cooled HeCd lasers are capable of providing adequate resolution for vibariate chromosome analysis and sorting for many flow cytogenetic applications.

  10. Studies on the fabrication of Ag/Hg1Ba2Ca1Cu2O6+dgr/CdSe heterostructures using the pulse electrodeposition technique

    NASA Astrophysics Data System (ADS)

    Shivagan, D. D.; Shirage, P. M.; Pawar, S. H.

    2004-03-01

    Metal/superconductor/semiconductor (Ag/Hg1Ba2Ca1Cu2O6+dgr (Hg-1212)/CdSe) heterostructures have been successfully fabricated using the pulse electrodeposition technique. The electrochemical parameters are optimized and diffusion free growth of CdSe on to Ag/Hg-1212 was obtained by employing underpotential deposition and by studying nucleation and growth mechanism during deposition. The heterostructures are characterized by x-ray diffraction, scanning electron microscopy studies and low-temperature four-probe electrical resistivity measurements. After the deposition of CdSe, the critical transition temperature of Hg-1212 films was found to be increased from 115 K with Jc (77 K) = 1.7 × 103 A cm-2 to 117.2 K with Jc (77 K) = 1.91 × 103 A cm-2. Tc and Jc (77 K) values were 120.3 K and 3.7 × 103 A cm-2, respectively, when the heterostructure was irradiated with red He-Ne laser. The improvements in superconducting properties of Hg-1212 in Ag/Hg-1212/CdSe heterostructures have been explained at length in this paper.

  11. Theoretical and experimental investigation of doping M in ZnSe (M = Cd, Mn, Ag, Cu) clusters: optical and bonding characteristics.

    PubMed

    Xu, Shuhong; Xu, Xiaojing; Wang, Chunlei; Zhao, Zengxia; Wang, Zhuyuan; Cui, Yiping

    2016-03-01

    The optical and bonding characteristics of doping ZnSe quantum dots (QDs) were investigated. Cd-, Mn-, Ag- and Cu-doped ZnSe were synthesized in aqueous solution. Theoretically, the intensity of the Cd-Se bond was similar to that of the Zn-Se bond, which illustrates that Cd can be doped into ZnSe materials at any ratio. We found that Mn-Se bonding was stronger than Zn-Se bonding. Ag-doped ZnSe nanoclusters show the same bonding and configuration as Cu-doped ZnSe. Moreover, Cd can be doped into ZnSe using both the substitution- and vacancy-doping method. For Mn-doped ZnSe clusters, small amounts of Mn impurity lead to stronger bonding with Se, but larger amounts of Mn impurity led to the formation of a Mn-Mn metal bond. The theoretical results show that it is difficult to form a vacancy-doping cluster for Mn-doped ZnSe materials. In experiments, the absorption and photoluminescence (PL) spectral wavelengths of Mn-doped ZnSe nanocrystals were the same as those of pure ZnSe nanocrystals, showing that the Mn impurity is not doped into ZnSe nanocrystals. Ag- and Cu-doped ZnSe nanocrystals have the same PL characteristics. The doping of an impurity is related to the solubility product, and not the bonding intensity.

  12. Cadmium content of plants as affected by soil cadmium concentration

    SciTech Connect

    Lehoczky, E.; Szabados, I.; Marth, P.

    1996-12-31

    Pot experiments were conducted in greenhouse conditions to study the effects of increasing cadmium (Cd) levels on biomass production and Cd contents in corn, (Zea mays L.), garlic (Allium sativum L.), and spinach (Spinacia oleracea L.). Plants were grown in two soil types: Eutric cambisol soil and A gleyic luvisol soil. Spinach proved to be the most sensitive to Cd treatments as its biomass considerably decreased with the increasing Cd levels. Cadmium contents of the three crops increased with increasing levels of Cd applications. Statistical differences were observed in the Cd contents of crops depending on soil type. With the same Cd rates, Cd tissue concentration of test plants grown in the strongly acidic Gleyic luvisol soil were many times higher than that of plants grown in a neutral Eutric cambisol soil. 14 refs., 4 tabs.

  13. Cadmium-Free InP/ZnSeS/ZnS Heterostructure-Based Quantum Dot Light-Emitting Diodes with a ZnMgO Electron Transport Layer and a Brightness of Over 10 000 cd m(-2).

    PubMed

    Wang, Hung Chia; Zhang, Heng; Chen, Hao Yue; Yeh, Han Cheng; Tseng, Mei Rurng; Chung, Ren Jei; Chen, Shuming; Liu, Ru Shi

    2017-04-01

    Cadmium-free thick-shelled InP/ZnSeS/ZnS quantum dot (QD) was synthesized using the heating-up approach. This quantum dots was used in inverted quantum dots light emitting diode (QLED) devices. The brightness of the inverted QLED device can reach a brightness of over 10 000 cd m(-2) , low turn-on voltage (2.2 V), and high power efficiency (4.32 lm W(-1) ).

  14. The energy band diagram and photovoltaic characteristic of nano p-AgInTe2/n-CdS{0.4}Se{0.6} heterojunction

    NASA Astrophysics Data System (ADS)

    El-Barry, A. M. A.

    2007-12-01

    Nano p-AgInTe{2}/n-CdS{0.4}Se{0.6} heterojunction was constructed. The dark current voltage characteristics of the prepared junction have been investigated in a temperature range from 303 to 423 K. The operating conduction mechanism was found to be Pool-Frenkel emission for T > 323 K and V < +0.8 volt. The supposed band diagram of p-AgInTe{2}/n-CdS{0.4}Se{0.6} heterojunction is exhibited. Analysis of the photovoltaic characteristic, at room temperature and under illumination of 2.7 W/m2, lead to the determination of some solar cell parameters, such as; the short circuit current, the open circuit voltage, the fill factor and the power conversion efficiency.

  15. Environmentally benign and efficient Ag2S-ZnO nanowires as photoanodes for solar cells: comparison with CdS-ZnO nanowires.

    PubMed

    Hwang, Insung; Yong, Kijung

    2013-02-04

    In this work, we develop a low-temperature, facile solution reaction route for the fabrication of quantum-dot-sensitized solar cells (QDSSCs) containing Ag(2)S-ZnO nanowires (NWs), simultaneously ensuring low manufacturing costs and environmental safety. For comparison, a CdS-ZnO NW photoanode was also prepared using the layer-by-layer growth method. Ultraviolet photoelectron spectroscopy analysis revealed type-II band alignments for the band structures of both photoanodes which facilitate electron transfer/collection. Compared to CdS-ZnO QDSSCs, Ag(2)S-ZnO QDSSCs exhibit a considerably higher short-circuit current density (J(sc)) and a strongly enhanced light-harvesting efficiency, but lower open-circuit voltages (V(oc)), resulting in almost the same power-conversion efficiency of 1.2 %. Through this work, we demonstrate Ag(2)S as an efficient quantum-dot-sensitizing material that has the potential to replace Cd-based sensitizers for eco-friendly applications.

  16. Mineral commodity profiles: Cadmium

    USGS Publications Warehouse

    Butterman, W.C.; Plachy, Jozef

    2004-01-01

    Overview -- Cadmium is a soft, low-melting-point metal that has many uses. It is similar in abundance to antimony and bismuth and is the 63d element in order of crustal abundance. Cadmium is associated in nature with zinc (and, less closely, with lead and copper) and is extracted mainly as a byproduct of the mining and processing of zinc. In 2000, it was refined in 27 countries, of which the 8 largest accounted for two-thirds of world production. The United States was the third largest refiner after Japan and China. World production in 2000 was 19,700 metric tons (t) and U.S. production was 1,890 t. In the United States, one company in Illinois and another in Tennessee refined primary cadmium. A Pennsylvania company recovered cadmium from scrap, mainly spent nickel-cadmium (NiCd) batteries. The supply of cadmium in the world and in the United States appears to be adequate to meet future industrial needs; the United States has about 23 percent of the world reserve base.

  17. Metallothionein and bioaccumulation of cadmium in juvenile bluegills exposed to aqueous and sediment-associated cadmium

    SciTech Connect

    Cope, W.G.

    1991-01-01

    The author evaluated metallothionein (MT), free (unbound) hepatic cadmium and whole body cadmium as indicators of cadmium exposure in juvenile bluegills Lepomis macrochirus in laboratory tests. Two types of cadmium exposure were tested; aqueous and sediment-associated. In the aqueous tests, fish were exposed to cadmium (0.0 to 32.3 [mu]g/L) in an intermittent-flow diluter. In the sediment-associated cadmium test, fish were exposed to resuspended river sidment containing 1.3 to 21.4 [mu]g Cd/g (dry weight) at a nominal total suspended solids concentration of 1,000 mg/L in revolving, circular glass exposure chambers. Total cadmium concentrations were measured in various bluegill liver fractions, whole bluegill, water, and resuspended sediment to assess the partitioning and bioaccumulation of cadmium after the tests. Mean concentrations of MT and free cadmium in bluegill livers and concentrations of cadmium in whole bluegills were positively correlated with aqueous cadmium concentration and were equally suitable as indicators of aqueous cadmium exposure. Sediment-associated cadmium was biologically available, but to a lesser extent than aqueous cadmium. Cadmium concentrations in whole bluegills exposed to resuspended river sediment were 1.5- to 3.5-fold the concentrations in bluegills in sediment-free controls. Free cadmium and MT concentrations in bluegill liver and whole-body cadmium concentrations in bluegills were positively correlated with the cadmium concentrations in filtered water, resuspended sediment, and bulk river sediment; however, whole-body cadmim concentrations were a more sensitive indicator of exposure to sediment-associated cadmium than either free cadmium or MT concentratons in liver.

  18. Antibacterial potential of rutin conjugated with thioglycolic acid capped cadmium telluride quantum dots (TGA-CdTe QDs)

    NASA Astrophysics Data System (ADS)

    Ananth, Devanesan Arul; Rameshkumar, Angappan; Jeyadevi, Ramachandran; Jagadeeswari, Sivanadanam; Nagarajan, Natarajan; Renganathan, Rajalingam; Sivasudha, Thilagar

    2015-03-01

    Quantum dots not only act as nanocarrier but also act as stable and resistant natural fluorescent bio markers used in various in vitro and in vivo photolabelling and biological applications. In this study, the antimicrobial potential of TGA-CdTe QDs and commercial phenolics (rutin and caffeine) were investigated against Escherichiacoli. UV absorbance and fluorescence quenching study of TGA-CdTe QDs with rutin and caffeine complex was measured by spectroscopic technique. QDs-rutin conjugate exhibited excellent quenching property due to the -OH groups present in the rutin structure. But the same time caffeine has not conjugated with QDs because of lacking of -OH group in its structure. Photolabelling of E. coli with QDs-rutin and QDs-caffeine complex was analyzed by fluorescent microscopic method. Microbe E. coli cell membrane damage was assessed by atomic force (AFM) and confocal microscopy. Based on the results obtained, it is suggested that QDs-rutin conjugate enhance the antimicrobial activity more than the treatment with QDs, rutin and caffeine alone.

  19. High-sensitivity brain SPECT system using cadmium telluride (CdTe) semiconductor detector and 4-pixel matched collimator

    NASA Astrophysics Data System (ADS)

    Suzuki, Atsuro; Takeuchi, Wataru; Ishitsu, Takafumi; Tsuchiya, Katsutoshi; Morimoto, Yuichi; Ueno, Yuichiro; Kobashi, Keiji; Kubo, Naoki; Shiga, Tohru; Tamaki, Nagara

    2013-11-01

    For high-sensitivity brain imaging, we have developed a two-head single-photon emission computed tomography (SPECT) system using a CdTe semiconductor detector and 4-pixel matched collimator (4-PMC). The term, ‘4-PMC’ indicates that the collimator hole size is matched to a 2 × 2 array of detector pixels. By contrast, a 1-pixel matched collimator (1-PMC) is defined as a collimator whose hole size is matched to one detector pixel. The performance of the higher-sensitivity 4-PMC was experimentally compared with that of the 1-PMC. The sensitivities of the 1-PMC and 4-PMC were 70 cps/MBq/head and 220 cps/MBq/head, respectively. The SPECT system using the 4-PMC provides superior image resolution in cold and hot rods phantom with the same activity and scan time to that of the 1-PMC. In addition, with half the usual scan time the 4-PMC provides comparable image quality to that of the 1-PMC. Furthermore, 99mTc-ECD brain perfusion images of healthy volunteers obtained using the 4-PMC demonstrated acceptable image quality for clinical diagnosis. In conclusion, our CdTe SPECT system equipped with the higher-sensitivity 4-PMC can provide better spatial resolution than the 1-PMC either in half the imaging time with the same administered activity, or alternatively, in the same imaging time with half the activity.

  20. Effect of Chemical Charging/Discharging on Plasmonic Behavior of Silver Metal Nanoparticles Prepared using Citrate-Stabilized Cadmium Selenide Quantum Dots.

    PubMed

    Ingole, Pravin P; Bhat, Mohsin A

    2016-10-18

    The thermodynamics and kinetics of the chemical and electrochemical charging of a catalyst surface are very important to understand its applicability as a catalyst material, particularly in redox catalysis. Through the present study, we hereby communicate the results obtained from our detailed investigations related to the effect of chemical charging on the plasmonic behavior of silver metal nanoparticles (Ag MNPs) as redox catalysts. Two different batches of Ag MNPs were prepared through thermally assisted chemical reduction of silver ions. The difference in these batches was the use or not of citrate-capped cadmium selenide quantum dots (Q-CdSe) for the reduction of solution-phase silver ions to their colloidal plasmonic phase. The charge on the surfaces of the Ag MNPs was varied by the chemical electron injection method by using BH4(-) ions from a NaBH4 solution. The processes of charging and discharging were monitored by using UV/Vis absorption spectroscopy. The impact of the concentration of the reductant on the charging and discharging processes was also investigated. The Ag MNPs were also tested for their voltammetric response, wherein it was observed that it was more difficult to oxidize the Ag MNPs prepared with Q-CdSe seeds than to oxidize Ag MNPs prepared without Q-CdSe particles. Our results demonstrate that Q-CdSe seeds not only enhance the redox catalytic activity of Ag MNPs but also provide stability towards polarization of their plasmonic behavior.

  1. Influences of dissolved and colloidal organic carbon on the uptake of Ag, Cd, and Cr by the marine mussel Perna viridis.

    PubMed

    Pan, Jin-Fen; Wang, Wen-Xiong

    2004-06-01

    The cross-flow ultrafiltration and radiotracer techniques were used to study the influences of natural dissolved organic carbon (DOC) and colloidal organic carbon (COC) on the bioavailability of Ag, Cd, and Cr to the green mussel Perna viridis. We examined the uptake of these metals by the mussels at different concentrations of DOC and COC from different origins (estuarine, coastal, and diatom decomposed). Using the DOC originating from the decomposed diatom (Thalassiosira pseudonana), we demonstrated that Cd and Cr uptake, quantified by the concentration factor (DCF), increased linearly with increasing DOC concentration. There was, however, no consistent influence of natural DOC concentration on the metal uptake when the DOC was obtained from different sources of seawater (coastal and estuarine). The influences of COC on metal bioavailability were metal-specific and dependent on the geochemical properties of colloids and colloid-metal complexation. Cd uptake rate was not influenced by the COC concentrations. Uptake of diatom-decomposed colloidal Cr was enhanced by 3.4x, whereas the uptake of diatom-decomposed colloidal Ag was decreased by 8.2x compared with the uptake of low molecular weight Cr and Ag (<1 kDa). The uptake of diatom-decomposed colloidal Cr and Ag was generally lower than the uptake of metals bound with the same type of colloids for 2 days. Further aging of the colloid-metal binding reduced metal bioavailability to the mussels. In the presence of different sizes of colloidal particles where there was no major binding of colloids with the metals, metal uptake by the mussels was not influenced by different COC concentrations. Overall, our study suggests that although metal dissociation from colloids may be an important step for the uptake of colloidal metals, other mechanisms such as pinocytosis and co-transport may also be involved in the uptake of these metals, especially in aquatic environments with high DOC and COC concentrations.

  2. Chelation of cadmium.

    PubMed Central

    Andersen, O

    1984-01-01

    The toxicity of cadmium is determined by chelation reactions: in vivo, Cd2+ exists exclusively in coordination complexes with biological ligands, or with administered chelating agents. The Cd2+ ion has some soft character, but it is not a typical soft ion. It has a high degree of polarizability, and its complexes with soft ligands have predominantly covalent bond characteristics. Cd2+ forms the most stable complexes with soft donor atoms (S much greater than N greater than 0). The coordination stereochemistry of Cd2+ is unusually varied, including coordination numbers from 2 to 8. Even though the Cd2+ ion is a d10 ion, disturbed coordination geometries are often seen. Generally, the stability of complexes increases with the number of coordination groups contributed by the ligand; consequently, complexes of Cd2+ with polydentate ligands containing SH groups are very stable. Cd2+ in metallothionein (MT) is coordinated with 4 thiolate groups, and the log stability constant is estimated to 25.5. Complexes between Cd2+ and low molecular weight monodentate or bidentate ligands, e.g., free amino acids (LMW-Cd), seem to exist very briefly, and Cd2+ is rapidly bound to high molecular weight proteins, mainly serum albumin. These complexes (HMW-Cd) are rapidly scavenged from blood, mainly by the liver, and Cd2+ is redistributed to MT. After about 1 day the Cd-MT complex (MT-Cd) almost exclusively accounts for the total retained dose of Cd2+, independent of the route of exposure. MT-Cd is slowly transferred to and accumulated in kidney cortex. The acute toxicity and interorgan distribution of parenterally administered Cd2+ are strongly influenced by preceding MT induction, or decreased capacity for MT synthesis; however, the gastrointestinal (GI) uptake of Cd2+ seems unaffected by preceding MT induction resulting in considerable capacity for Cd2+ chelation in intestinal mucosa, and this finding indicates that endogenous MT is not involved in Cd2+ absorption. The toxicity of

  3. Route and Regulation of Zinc, Cadmium, and Iron Transport in Rice Plants (Oryza sativa L.) during Vegetative Growth and Grain Filling: Metal Transporters, Metal Speciation, Grain Cd Reduction and Zn and Fe Biofortification.

    PubMed

    Yoneyama, Tadakatsu; Ishikawa, Satoru; Fujimaki, Shu

    2015-08-13

    Zinc (Zn) and iron (Fe) are essential but are sometimes deficient in humans, while cadmium (Cd) is toxic if it accumulates in the liver and kidneys at high levels. All three are contained in the grains of rice, a staple cereal. Zn and Fe concentrations in rice grains harvested under different levels of soil/hydroponic metals are known to change only within a small range, while Cd concentrations show greater changes. To clarify the mechanisms underlying such different metal contents, we synthesized information on the routes of metal transport and accumulation in rice plants by examining metal speciation, metal transporters, and the xylem-to-phloem transport system. At grain-filling, Zn and Cd ascending in xylem sap are transferred to the phloem by the xylem-to-phloem transport system operating at stem nodes. Grain Fe is largely derived from the leaves by remobilization. Zn and Fe concentrations in phloem-sap and grains are regulated within a small range, while Cd concentrations vary depending on xylem supply. Transgenic techniques to increase concentrations of the metal chelators (nicotianamine, 2'-deoxymugineic acid) are useful in increasing grain Zn and Fe concentrations. The elimination of OsNRAMP5 Cd-uptake transporter and the enhancement of root cell vacuolar Cd sequestration reduce uptake and root-to-shoot transport, respectively, resulting in a reduction of grain Cd accumulation.

  4. Route and Regulation of Zinc, Cadmium, and Iron Transport in Rice Plants (Oryza sativa L.) during Vegetative Growth and Grain Filling: Metal Transporters, Metal Speciation, Grain Cd Reduction and Zn and Fe Biofortification

    PubMed Central

    Yoneyama, Tadakatsu; Ishikawa, Satoru; Fujimaki, Shu

    2015-01-01

    Zinc (Zn) and iron (Fe) are essential but are sometimes deficient in humans, while cadmium (Cd) is toxic if it accumulates in the liver and kidneys at high levels. All three are contained in the grains of rice, a staple cereal. Zn and Fe concentrations in rice grains harvested under different levels of soil/hydroponic metals are known to change only within a small range, while Cd concentrations show greater changes. To clarify the mechanisms underlying such different metal contents, we synthesized information on the routes of metal transport and accumulation in rice plants by examining metal speciation, metal transporters, and the xylem-to-phloem transport system. At grain-filling, Zn and Cd ascending in xylem sap are transferred to the phloem by the xylem-to-phloem transport system operating at stem nodes. Grain Fe is largely derived from the leaves by remobilization. Zn and Fe concentrations in phloem-sap and grains are regulated within a small range, while Cd concentrations vary depending on xylem supply. Transgenic techniques to increase concentrations of the metal chelators (nicotianamine, 2′-deoxymugineic acid) are useful in increasing grain Zn and Fe concentrations. The elimination of OsNRAMP5 Cd-uptake transporter and the enhancement of root cell vacuolar Cd sequestration reduce uptake and root-to-shoot transport, respectively, resulting in a reduction of grain Cd accumulation. PMID:26287170

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

    PubMed Central

    Kimi, Melody; Shamsuddin, Mustaffa

    2014-01-01

    Summary 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. PMID:24991495

  6. Effect of the Concentration on the X-ray Luminescence Efficiency of a Cadmium Selenide/Zinc Sulfide (CdSe/ZnS) Quantum Dot Nanoparticle Solution

    NASA Astrophysics Data System (ADS)

    Valais, I.; Michail, C.; Nikolopoulos, D.; Fountzoula, C.; Bakas, A.; Yannakopoulos, P.; Fountos, G.; Panayiotakis, G.; Kandarakis, I.

    2015-09-01

    In the current study preliminary results on the luminescence efficiency (LE) of toluene dissolved Cadmium Selenide/Zinc Sulfide (CdSe/ZnS, Sigma-Aldrich, Lumidot 694622) quantum dot samples (QDs) after exposure to X-rays of variable radiation flux are shown. The distinctive influence of the weight over volume (w/v) concentration of the samples in LE was investigated. The light emission of the QDs was additionally measured after UV irradiation. The distribution of the emitted light was symmetrical with a maximum at 590 nm. The w/v concentration of the QDs varied between 7.1×10-5 mg/mL to 28.4×10-5 mg/mL. The samples were handled in a cubic 12.5×12.5×45mm3 quartz cuvette. Each sample was excited under X-ray irradiation, in the energy range from 50 to 130 kVp using a BMI General Medical Merate tube with rotating Tungsten anode and inherent filtration equivalent to 2 mm Al. The X-ray LE, induced by the 28.4×10-5 mg/mL QDs found higher, however, the distinction was vague in the highly concentrated samples. The maximum efficiency was obtained at the 90 kVp for QDs with 21.3×10-5 mg/mL w/v concentration. In the high energy range (120-130 kVp) all concentration levels exhibited comparable X-ray induced LE. The luminescence properties of the investigated QDs appear promising for X-ray detection applications.

  7. NiCd battery electrodes, C-150

    NASA Technical Reports Server (NTRS)

    Holleck, G.; Turchan, M.; Hopkins, J.

    1972-01-01

    Electrodes for a nongassing negative limited nickel-cadmium cell are discussed. The key element is the development of cadmium electrodes with high hydrogen overvoltage. For this, the following electrode structures were manufactured and their physical and electrochemical characteristics were evaluated: (1) silver-sinter-based Cd electrodes, (2) Teflon-bonded Cd electrodes, (3) electrodeposited Cd sponge, and (4) Cd-sinter structures.

  8. Cadmium telluride in tellurium—cadmium films consisting of ultradispersed particles

    NASA Astrophysics Data System (ADS)

    Tuleushev, Yu. Zh.; Volodin, V. N.; Migunova, A. A.; Lisitsyn, V. N.

    2015-08-01

    Solid solutions of tellurium in cadmium, cadmium in tellurium, and cadmium in cadmium telluride synthesized during sputtering are formed for the first time by ion-plasma sputtering and the codeposition of ultradispersed Te and Cd particle fluxes onto substrates moving with respect to the fluxes. This fact supports thermofluctuation melting and coalescence of small particles. The lattice parameter of cadmium telluride, which coexists with an amorphous solid solution of tellurium in cadmium in a coating, is smaller than the tabulated value and reaches it when the cadmium concentration in a coating increases to 70 at %. The lattice parameter of the fcc lattice of cadmium telluride increases with the cadmium concentration in a coating according to the linear relation a = 0.0002CCd + 0.6346 nm (where CCd is the cadmium concentration in the coating, at %), which is likely to indicate a certain broadening of the homogeneity area. The estimation of the particle size shows that the cadmium telluride grain size is 10-15 nm, which implies that the coatings are nanocrystalline. The absorption and transmission spectra of the tellurium—cadmium films at the fundamental absorption edge demonstrate that their energy gaps are larger than that of stoichiometric CdTe, which can be explained by the experimental conditions of crystal structure formation.

  9. Mercury Cadmium Selenide for Infrared Detection

    DTIC Science & Technology

    2013-06-01

    REPORT Mercury cadmium selenide for infrared detection 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: Samples of HgCdSe alloys were grown via molecular...NUMBER John Dinan 512-245-6711 3. DATES COVERED (From - To) Standard Form 298 (Rev 8/98) Prescribed by ANSI Std. Z39.18 - Mercury cadmium selenide for...PAGE (SF298) (Continuation Sheet) Continuation for Block 13 ARO Report Number Mercury cadmium selenide for infrared detection Block 13

  10. Dynamically tuning emission band of CdSe/ZnS quantum dots assembled on Ag nanorod array: plasmon-enhanced Stark shift.

    PubMed

    Peng, Xiao-Niu; Zhou, Zhang-Kai; Zhang, Wei; Hao, Zhong-Hua

    2011-11-21

    We demonstrate tuning emission band of CdSe/ZnS semiconductor quantum dots (SQDs) closely-packed in the proximity of Ag nanorod array by dynamically adjusting exciton-plasmon interaction. Large red-shift is observed in two-photon luminescence (TPL) spectra of the SQDs when the longitudinal surface plasmon resonance (LSPR) of Ag nanorod array is adjusted to close to excitation laser wavelength, and the spectral red-shift of TPL reaches as large as 101 meV by increasing excitation power, which is slightly larger than full width at half-maximum of emission spectrum of the SQDs. The observed LSPR-dependent spectral shifting behaviors are explained by a theoretical model of plasmon-enhanced quantum-confined Stark effect. These observations could find the applications in dynamical information processing in active plasmonic and photonic nanodevices.

  11. Cadmium toxicity

    PubMed Central

    Wan, Lichuan; Zhang, Haiyan

    2012-01-01

    Cadmium is a well-known environmental pollutant with distinctly toxic effects on plants. It can displace certain essential metals from a wealth of metalloproteins, and thus disturb many normal physiological processes and cause severe developmental aberrant. The harmful effects of cadmium stress include, but are not limited to: reactive oxygen species overproduction, higher lipid hydroperoxide contents, and chloroplast structure change, which may lead to cell death. Plants have developed diverse mechanisms to alleviate environmental cadmium stress, e.g., cadmium pump and transporting cadmium into the leaf vacuoles. This mini-review focuses on the current research into understanding the cellular mechanisms of cadmium toxicity on cytoskeleton, vesicular trafficking and cell wall formation in plants. PMID:22499203

  12. Cadmium Alternatives

    DTIC Science & Technology

    2012-08-01

    including cadmium! Cadmium Replacements (With MIL-DTL-38999 Designations) Zn/Ni (Class Z) Per ASTM B 841, type D (black) Electroless Nickel plus... Electroless nickel / PTFE (Durmalon®) Electroplated Aluminum (Alumiplate®) Electroplated tin-zinc (SnZn) Control: cadmium with hexavalent chromate... electroless nickel / PTFE performed well Electroplated aluminum performed did not perform well on connectors Electroplated aluminum did not

  13. Concentrations of metals and potential metal-binding compounds and speciation of Cd, Zn and Cu in phloem and xylem saps from castor bean plants (Ricinus communis) treated with four levels of cadmium.

    PubMed

    Hazama, Kenji; Nagata, Shinji; Fujimori, Tamaki; Yanagisawa, Shuichi; Yoneyama, Tadakatsu

    2015-06-01

    We examined the concentrations of metals (Cd, Zn, Cu, Fe and Mn) and potential metal-binding compounds [nicotianamine (NA), thiol compounds and citrate] in xylem and phloem saps from 4-week-old castor bean plants (Ricinus communis) treated with 0 (control), 0.1, 1.0, and 10 μM Cd for 3 weeks. Treatment with 0.1 and 1 μM Cd produced no visible damage, while 10 μM Cd retarded growth. Cadmium concentrations in both saps were higher than those in the culture solution at 0.1 μM, similar at 1.0 μM and lower at 10 μM. Cd at 10 μM reduced Cu and Fe concentrations in both saps. NA concentrations measured by capillary electrophoresis-mass spectrometry (MS) in xylem sap (20 μM) were higher than the Cu concentrations, and those in phloem sap (150 μM) were higher than those of Zn, Fe and Cu combined. Reduced glutathione concentrations differed in xylem and phloem saps (1-2 and 30-150 μM, respectively), but oxidized glutathione concentrations were similar. Phloem sap phytochelatin 2 concentration increased from 0.8 μM in controls to 8 μM in 10 μM Cd. Free citrate was 2-4 μM in xylem sap and 70-100 μM in phloem sap. Total bound forms of Cd in phloem and xylem saps from 1 μM Cd-treated plants were 54 and 8%, respectively. Treatment of phloem sap with proteinaseK reduced high-molecular compounds while increasing fractions of low-molecular Cd-thiol complexes. Zinc-NA, Fe-NA and Cu-NA were identified in the phloem sap fraction of control plants by electrospray ionization time-of-flight MS, and the xylem sap contained Cu-NA.

  14. Effects of metal-bearing nanoparticles (Ag, Au, CdS, ZnO, SiO2) on developing zebrafish embryos

    NASA Astrophysics Data System (ADS)

    María Lacave, José; Retuerto, Ander; Vicario-Parés, Unai; Gilliland, Douglas; Oron, Miriam; Cajaraville, Miren P.; Orbea, Amaia

    2016-08-01

    Due to the increasing commercialization of consumer and industrial products containing nanoparticles (NPs), an increase in the introduction of these materials into the environment is expected. NP toxicity to aquatic organisms depends on multiple biotic and abiotic factors, resulting in an unlimited number of combinations impossible to test in practice. The zebrafish embryo model offers a useful screening tool to test and rank the toxicity of nanomaterials according to those diverse factors. This work aims to study the acute and sublethal toxicity of a set of metal-bearing NPs displaying different properties, in comparison to that of the ionic and bulk forms of the metals, in order to establish a toxicity ranking. Soluble NPs (Ag, CdS and ZnO) showed the highest acute and sublethal toxicity, with LC50 values as low as 0.529 mg Ag l-1 for Ag NPs of 20 nm, and a significant increase in the malformation prevalence in embryos exposed to 0.1 mg Cd l-1 of CdS NPs of ˜4 nm. For insoluble NPs, like SiO2 NPs, acute effects were not observed during early embryo development due to the protective effect of the chorion. But effects on larvae could be expected, since deposition of fluorescent SiO2 NPs over the gill lamella and excretion through the intestine were observed after hatching. In other cases, such as for gold NPs, the toxicity could be attributed to the presence of additives (sodium citrate) in the NP suspension, as they displayed a similar toxicity when tested separately. Overall, the results indicated that toxicity to zebrafish embryos depends primarily on the chemical composition and, thus, the solubility of the NPs. Other characteristics, such as size, played a secondary role. This was supported by the observation that ionic forms of the metals were always more toxic than the nano forms, and bulk forms were the least toxic to the developing zebrafish embryos.

  15. Contents of Ag and other metals in food-contact plastics with nanosilver or Ag ion and their migration into food simulants.

    PubMed

    Ozaki, Asako; Kishi, Eri; Ooshima, Tomoko; Hase, Atsushi; Kawamura, Yoko

    2016-09-01

    Six nanosilver-labelled products and five silver ion (Ag(+))-labelled products were investigated to measure the migration of Ag from food-contact plastics, including nanosilver into various food simulants. The products were obtained in Japanese markets in 2012. Zinc (Zn), another major antimicrobial agent, and three harmful metals, cadmium (Cd), lead (Pb) and arsenic (As), were also examined. Ag and Zn were detected in all six nanosilver products at concentrations of 21-200 and 8.4-140 mg kg(-1), respectively. These metals were also detected in all five Ag(+) products at the same level as nanosilver products. Cd, Pb and As were not detected in any sample. Migrations of Ag and Zn were highest in 4% acetic acid, but also observed in water and 20% ethanol. Big differences were not observed in the migration ratio between nanosilver products and Ag(+) products. The ultrafiltration experiments suggested that the Ag that migrated from nanosilver products into 4% acetic acid was in its ionic form, while that into water and 20% ethanol was in its nanoparticle form.

  16. Cadmium sulfite hexahydrate revisited

    PubMed Central

    Baggio, Sergio; Ibáñez, Andrés; Baggio, Ricardo

    2008-01-01

    The present structural revision of the title compound, tetra­cadmium tetra­sulfite hexa­hydrate, [Cd4(SO3)4(H2O)5]·H2O, is a low-temperature upgrade (T = 100 K and R = 0.017) of the original room-temperature structure reported by Kiers & Vos [Cryst. Struct. Commun. (1978). 7, 399–403; T = 293 K and R = 0.080). The compound is a three-dimensional polymer with four independent cadmium centres, four sulfite anions and six water mol­ecules, five of them coordinated to two cadmium centres and the remaining one an unbound solvent mol­ecule which completes the asymmetric unit. There are two types of cadmium environment: CdO8 (through four chelating sulfite ligands) and CdO6 (by way of six monocoordinated ligands). The former groups form planar arrays [parallel to (001) and separated by half a unit cell translation along c], made up of chains running along [110] and [10], respectively. These chains are, in turn, inter­connected both in an intra­planar as well as in an inter­planar fashion by the latter CdO6 polyhedra into a tight three-dimensional framework. There is, in addition, an extensive network of hydrogen bonds, in which all 12 water H atoms act as donors and eight O atoms from all four sulfite groups and two water mol­ecules act as acceptors. PMID:21202728

  17. Copper-cadmium interaction in mice: effects of copper status on retention and distribution of cadmium after cadmium exposure

    SciTech Connect

    Bourcier, D.R.

    1982-01-01

    The role of increased dietary copper in altering the accumulation of cadmium and other metals in tissues, was investigated. Female Swiss-Webster mice were pretreated with cadmium or copper in drinking water for three weeks prior to cadmium exposure for an additional nine weeks, with sub groups from each dose level receiving Cu additions to the Cd supplemented water. In Cd pretreated animals, a significant decrease was observed in Cd concentrations in liver and kidney when Cu was added to Cd in drinking water. Cadmium levels in soluble protein fractions of liver of animals administered 5 ppm Cd were approximately three fold greater than that for the same Cd dose when Cu was added. The same was the case for the metallothionein-like protein fraction (MTP) of the liver cytosol. In copper pretreated animals similar trends were noted in that brain, spleen, liver (but not kidney) Cd levels were decreased in animals receiving Cu additions to the Cd dose. Increased binding of Cd to the MTP fraction was observed after both in vivo and in vitro exposure of intestinal mucosal cells to cadmium.

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

    SciTech Connect

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

    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.

  19. Lactation-induced cadmium-binding proteins

    SciTech Connect

    Bhattacharyya, M.H.; Solaiman, D.; Garvey, J.S.; Miyazaki, W.Y.

    1987-01-01

    Previously we have demonstrated an increase during midlactation in /sup 109/Cd adsorption and increased retention by the duodenum, kidney, and mammary tissue of mouse dams receiving environmental levels of cadmium//sup 109/Cd via drinking water, with little change in /sup 109/Cd retention in liver and jejunum compared to nonpregnant controls. Results are reported here of a study of cadmium deposition during midlactation as associated with induction of metallothionein (MT). A cadmium/hemoglobin (Cd/Hb) assay and radioimmunoassay for MT which measures heat-stable cadmium binding capacity in tissues was used to determine MT concentrations in fractions of kidney, liver, duodenum, and jejunum from female mice. Both assays demonstrated clear lactation-induced increases in MT concentrations in liver, kidney, and duodenum, with MT concentrations falling rapidly to control levels after weaning. 4 refs., 1 tab.

  20. Mechanisms of cadmium carcinogenesis

    SciTech Connect

    Joseph, Pius

    2009-08-01

    Cadmium (Cd), a heavy metal of considerable occupational and environmental concern, has been classified as a human carcinogen by the International Agency for Research on Cancer (IARC). The carcinogenic potential of Cd as well as the mechanisms underlying carcinogenesis following exposure to Cd has been studied using in vitro cell culture and in vivo animal models. Exposure of cells to Cd results in their transformation. Administration of Cd in animals results in tumors of multiple organs/tissues. Also, a causal relationship has been noticed between exposure to Cd and the incidence of lung cancer in human. It has been demonstrated that Cd induces cancer by multiple mechanisms and the most important among them are aberrant gene expression, inhibition of DNA damage repair, induction of oxidative stress, and inhibition of apoptosis. The available evidence indicates that, perhaps, oxidative stress plays a central role in Cd carcinogenesis because of its involvement in Cd-induced aberrant gene expression, inhibition of DNA damage repair, and apoptosis.

  1. Highly efficient blue-green quantum dot light-emitting diodes using stable low-cadmium quaternary-alloy ZnCdSSe/ZnS core/shell nanocrystals.

    PubMed

    Shen, Huaibin; Wang, Sheng; Wang, Hongzhe; Niu, Jinzhong; Qian, Lei; Yang, Yixing; Titov, Alexandre; Hyvonen, Jake; Zheng, Ying; Li, Lin Song

    2013-05-22

    High-quality blue-green emitting ZnxCd(1-x)S(1-y)Se(y)/ZnS core/shell quantum dots (QDs) have been synthesized by a phosphine-free method. The quantum yields of as-synthesized ZnxCd(1-x)S(1-y)Se(y)/ZnS core/shell QDs can reach 50-75% with emissions between 450 and 550 nm. The emissions of such core/shell QDs are not susceptible to ligand loss through the photostability test. Blue-green light-emitting diodes (LEDs) based on the low-cadmium ZnxCd(1-x)S(1-y)Se(y)/ZnS core/shell QDs have been successfully demonstrated. Composite films of poly[9,9-dioctylfluorene-co-N-[4-(3-methylpropyl)]-diphenylamine] (TFB) and ZnO nanoparticle layers were chosen as the hole-transporting and the electron-transporting layers, respectively. Highly bright blue-green QD-based light-emitting devices (QD-LEDs) showing maximum luminance up to 10000 cd/m(2), in particular, the blue QD-LEDs show an unprecedentedly high brightness over 4700 cd/m(2) and peak external quantum efficiency (EQE) of 0.8%, which is the highest value ever reported. These results signify a remarkable progress in QD-LEDs and offer a practicable platform for the realization of QD-based blue-green display and lighting.

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

    PubMed

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

    2017-03-15

    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.

  3. Soil biogeochemistry, plant physiology and phytoremediation of cadmium contaminated soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cadmium (Cd) loading in soil and the environment has been accelerated worldwide due to enhanced industrialization and intensified agricultural production, particularly in the developing countries. Soil Cd pollution, resulting from both anthropogenic and geogenic sources, has posed an increasing chal...

  4. Interpreting NHANES biomonitoring data, cadmium.

    PubMed

    Ruiz, Patricia; Mumtaz, Moiz; Osterloh, John; Fisher, Jeffrey; Fowler, Bruce A

    2010-09-15

    Cadmium (Cd) occurs naturally in the environment and the general population's exposure to it is predominantly through diet. Chronic Cd exposure is a public health concern because Cd is a known carcinogen; it accumulates in the body and causes kidney damage. The National Health and Nutritional Examination Survey (NHANES) has measured urinary Cd; the 2003-2004 NHANES survey cycle reported estimates for 2257 persons aged 6 years and older in the Fourth National Report on Human Exposure to Environmental Chemicals. As part of translational research to make computerized models accessible to health risk assessors we re-coded a cadmium model in Berkeley Madonna simulation language. This model was used in our computational toxicology laboratory to predict the urinary excretion of cadmium. The model simulated the NHANES-measured data very well from ages 6 to 60+ years. An unusual increase in Cd urinary excretion was observed among 6-11-year-olds, followed by a continuous monotonic rise into the seventh decade of life. This observation was also made in earlier studies that could be life stage-related and a function of anatomical and phsysiological changes occurring during this period of life. Urinary excretion of Cd was approximately twofold higher among females than males in all age groups. The model describes Cd's cumulative nature in humans and accommodates the observed variation in exposure/uptake over the course of a lifetime. Such models may be useful for interpreting biomonitoring data and risk assessment.

  5. Cadmium accumulation and depuration in Anodonta anatina exposed to cadmium chloride or cadmium-EDTA complex

    SciTech Connect

    Holwerda, D.A.; Hemelraad, J.; Veenhof, P.R.; Zandee, D.I.

    1988-03-01

    The authors have previously reported on the uptake and distribution of cadmium in unionids, experimentally exposed to cadmium chloride. The purpose of the present investigation was to study the effect of metal chelation on cadmium kinetics, including metal elimination in the post-exposure phase. Generally, chelation of ionic metal by natural substances like humic acids or by synthetic compounds like EDTA decreases its environmental toxicity through a diminished rate of uptake, as compared with the free ion. The influences of metal chelation on bioconcentration and on toxicity do not always run parallel. To their knowledge, there are no data on the effect of chelation on metal kinetics in freshwater clams. Data on rates of cadmium elimination from aquatic invertebrates are highly divergent, but Cd excretion is invariably found to be smaller than uptake.

  6. Material and detector properties of cadmium manganese telluride (Cd1-xMnxTe) crystals grown by the modified floating-zone method

    SciTech Connect

    Hossain, A.; Gu, G. D.; Bolotnikov, A. E.; Camarda, G. S.; Cui, Y.; Roy, U. N.; Yang, G.; Liu, T.; Zhong, R.; Schneelock, J.; James, R. B.

    2014-12-24

    We demonstrated the material- and radiation-detection properties of cadmium manganese telluride (Cd1-xMnxTe; x=0.06), a wide-band-gap semiconductor crystal grown by the modified floating-zone method. We investigated the presence of various bulk defects, such as Te inclusions, twins, and dislocations of several as-grown indium-doped Cd1-xMnxTe crystals using different techniques, viz., IR transmission microscopy, and chemical etching. We then fabricated four planar detectors from selected CdMnTe crystals, characterized their electrical properties, and tested their performance as room-temperature X- and gamma-ray detectors. Thus, our experimental results show that CMT crystals grown by the modified floating zone method apparently are free from Te inclusions. However, we still need to optimize our growth parameters to attain high-resistivity, large-volume single-crystal CdMnTe.

  7. High transmittance cadmium oxysulfide Cd(S,O) buffer layer grown by triton X-100 mediated chemical bath deposition for thin-film heterojunction solar cells

    NASA Astrophysics Data System (ADS)

    Ballipinar, Faruk; Rastogi, A. C.

    2017-01-01

    Polycrystalline 100-190 nm Cd(S,O) n-type semiconductor thin films of high transparency in the visible range are deposited by a surfactant Triton X-100 mediated chemical bath deposition process. The crystalline structure of the films revealed by X-ray diffraction data shows a cubic-CdO phase signified by (111) and (200) planes alongside the (002), (220), and (110) planes from hexagonal-CdS. The invariance of the 2θ position of the (002) CdS diffraction is interpreted in terms of the growth of the composite film essentially by the formation of a dilute interstitial alloy of CdO and CdS. This is confirmed by Raman spectra which, besides the CdS 1LO and 2LO modes at 300 and 600 cm-1, also show Raman lines from CdO at 1098 cm-1 and 952 cm-1 assigned as overtone of 2LO phonon modes and 556 cm-1 due to band crossing between LO and TO modes of CdO. Optical spectra of Cd(S,O) films show a median transmittance of >85% compared to ˜70% for CdS films in the 550-1000 nm wavelength range. The Cd(S,O) films show optical bandgap varying from 2.34 to 2.26 eV with increasing CdO fraction but retain high sub-bandgap transmission and sharp band edge threshold. The Cd(S,O) films thus offer an alternative to the CdS buffer layer in the heterojunction solar cells, which has major shortcoming of poor stability and high sub-bandgap absorption. The photoluminescence spectra of Cd(S,O) films show three green bands, of which one is the near band edge transition at 511.5 nm, the same as in CdS, the second band at 526.0 nm that red shifted from the CdS position is due to shallow donor-acceptor defects arising from structural change due to CdO, and the third band at 543.6 nm (2.28 eV) originates from direct band transition in CdO. The growth mechanism of Cd(S,O) films is described, which invokes that the Triton X-100 molecule modifies the microenvironment around adsorbed [Cd(NH3)4]2+ species, thereby inducing two concurrent reactions, one with SH- species that cause CdS formation and the

  8. Dietary assimilation of cadmium associated with bacterial exopolymer sediment coatings by the estuarine amphipod Leptocheirus plumulosus: Effects of Cd concentration and salinity

    USGS Publications Warehouse

    Schlekat, C.E.; Decho, Alan W.; Chandler, G.T.

    1999-01-01

    Bacterial extracellular substances (also known as exopolysaccharides, or EPS) may serve as vectors for trophic transfer of metals in benthic systems because these ubiquitous sediment coatings can sorb high concentrations of toxic metals, and because many benthic invertebrates assimilate EPS sediment coatings upon ingestion. We conducted 3 sets of experiments to determine the assimilative bioavailability of EPS-associated Cd to the benthic amphipod Leptocheirus plumulosus as a function of Cd concentration and salinity. Bioavailability was measured as L. plumulosus Cd assimilation efficiency (AE) from EPS-coated silica (EPS-Si) and from uncoated silica (NC-Si) using modified pulse-chase methods with the gamma-emitting radioisotope 109Cd. Cd AE was significantly greater from NC-Si than from EPS-Si at 7.5???, but not at 2.5 or 25???. Overall, Cd AE from EPS-Si was between 15.1 and 21.5%. Because EPS-Si sorbed more Cd than NC-Si, EPS coatings magnified the amount of Cd amphipods accumulated at each salinity by up to a factor of 10. Salinity did not directly affect Cd AE from EPS-Si, but because Cd-EPS partitioning increased with decreasing salinity, amphipods accumulated more Cd from EPS at the lowest Cd-EPS incubation salinity (2.5 ???) than at higher salinities (7.5 and 25 ???). Finally, Cd concentration in EPS exhibited an inverse relationship with Cd AE at 2.5 ???, but not at 25 ???. Specifically, Cd AE was 12 times greater at 1 compared with 10 ??g Cd ??g-1 EPS. Together, these results show that estuarine benthos can accumulate Cd from EPS sediment coatings, but that the degree to which this phenomenon occurs is dependent upon seawater salinity and Cd concentration in EPS.

  9. Solid-state synthesis, structure and properties of a novel open-framework cadmium selenite bromide: [Cd{sub 10}(SeO{sub 3}){sub 8}Br{sub 4}]·HBr·H{sub 2}O

    SciTech Connect

    Chen, Wen-Tong; Wang, Ming-Sheng; Wang, Guan-E; Chen, Hui-Fen; Guo, Guo-Cong

    2013-08-15

    A novel open-framework cadmium selenite bromide, [Cd{sub 10}(SeO{sub 3}){sub 8}Br{sub 4}]·HBr·H{sub 2}O (1), has been obtained by a solid-state reaction at 450 °C, and the structure has been determined by single-crystal X-ray diffraction analysis. Compound 1 crystallizes in Pbcm of the orthorhombic system: a=10.882(3), b=16.275(5), c=18.728(6) Å, V=3317(2) Å{sup 3}, R1/wR2=0.0411/0.0659. Compound 1 is characteristic of a novel 3-D open-framework structure, composing {sub ∞}{sup 2}[CdSeO{sub 3}] layers and the pillars of edge-shared CdO{sub 3}Br{sub 2} square pyramids. The lattice water molecules and the HBr molecules locate in the voids of the framework. Optical absorption spectrum of 1 reveals the presence of an optical gap of 1.65 eV. Solid-state photoluminescent study indicates that compound 1 exhibits strong violet emission. TG–DSC measurement shows that compound 1 is thermally stable up to 200 °C. - Graphical abstract: A metal selenite halide has been synthesized and features a 3-D open-framework structure, composing edge-shared CdO{sub 8} decahedra and pillars of edge-sharing pentahedra. UV–vis, TG–DSC and luminescent measurements are also reported. Highlights: • This paper reports a novel cadmium selenite bromide obtained by an intermediate-temperature solid-state reaction. • The title compound is characteristic of a novel 3-D open-framework structure, composing {sub ∞}{sup 2}[CdSeO{sub 3}] layers and the pillars of edge-shared CdO{sub 3}Br{sub 2} square pyramids. • The title compound is thermally stable up to 200 °C. • The title compound has an optical gap of 1.65 eV and exhibits strong violet emission.

  10. The relationship between cadmium in kidney and cadmium in urine and blood in an environmentally exposed population

    SciTech Connect

    Akerstrom, Magnus; Barregard, Lars; Lundh, Thomas; Sallsten, Gerd

    2013-05-01

    Introduction: Cadmium (Cd) is toxic to the kidney and a major part of the body burden occurs here. Cd in urine (U-Cd) and blood (B-Cd) are widely-used biomarkers for assessing Cd exposure or body burden. However, empirical general population data on the relationship between Cd in kidney (K-Cd), urine, and blood are scarce. Our objectives were to determine the relationship between cadmium in kidney, urine, and blood, and calculate the elimination half-time of Cd from the kidney. Methods: Kidney cortex biopsies, urine, and blood samples were collected from 109 living kidney donors. Cd concentrations were determined and the relationships between K-Cd, U-Cd, and B-Cd were investigated in regression models. The half-time of K-Cd was estimated from the elimination constant. Results: There was a strong association between K-Cd and U-Cd adjusted for creatinine (r{sub p} = 0.70, p < 0.001), while the association with B-Cd was weaker (r{sub p} = 0.44, p < 0.001). The relationship between K-Cd and U-Cd was nonlinear, with slower elimination of Cd at high K-Cd. Estimates of the K-Cd half-time varied between 18 and 44 years. A K-Cd of 25 μg/g corresponds to U-Cd of 0.42 μg/g creatinine in overnight urine (U-Cd/K-Cd ratio: about 1:60). Multivariate models showed Cd in blood and urinary albumin as determinants for U-Cd excretion. Discussion: In healthy individuals with low-level Cd exposure, there was a strong correlation between Cd in kidney and urine, especially after adjustment for creatinine. Urinary Cd was also affected by Cd in blood and urinary albumin. Previous estimates of the U-Cd/K-Cd ratio may underestimate K-Cd at low U-Cd. - Highlights: ► The first study of the relation between Cd in kidney, blood and urine at low U-Cd ► Simultaneous samples were collected from healthy kidney donors. ► There was a nonlinear relationship between cadmium in kidney and urine. ► Estimates of the kidney cadmium half-time were 18–44 years, depending on model used. ► Previous

  11. Different behavior of Staphylococcus epidermidis in intracellular biosynthesis of silver and cadmium sulfide nanoparticles: more stability and lower toxicity of extracted nanoparticles.

    PubMed

    Rezvani Amin, Zohreh; Khashyarmanesh, Zahra; Fazly Bazzaz, Bibi Sedigheh

    2016-09-01

    Chemical reagents that are used for synthesis of nanoparticles are often toxic, while biological reagents are safer and cost-effective. Here, the behavior of Staphylococcus epidermidis (ATCC 12228) was evaluated for biosynthesis of silver nanoparticles (Ag-NPs) and cadmium sulfide nanoparticles (CdS-NPs) using TEM images intra- and extracellularly. The bacteria only biosynthesized the nanoparticles intracellularly and distributed Ag-NPs throughout the cytoplasm and on outside surface of cell walls, while CdS-NPs only formed in cytoplasm near the cell wall. A new method for purification of the nanoparticles was used. TEM images of pure CdS-NPs confirmed biosynthesis of agglomerated nanoparticles. Biosynthetic Ag-NPs were more stable against bright light and aggregation reaction than synthetic Ag-NPs (prepared chemically) also biosynthetic Ag-NPs displayed lower toxicity in in vitro assays. CdS-NPs indicated no toxicity in in vitro assays. Biosynthetic nanoparticles as product of the detoxification pathway may be safer and more stable for biosensors.

  12. Absence of cadmium excretion and high assimilation result in cadmium biomagnification in a wolf spider.

    PubMed

    Hendrickx, Frederik; Maelfait, Jean-Pierre; Langenbick, Francis

    2003-07-01

    Cd biomagnification in the terrestrial food chain appears to be dependent on the physiological properties of the organisms rather than on their trophic level. Although high Cd body burdens in spiders from the field have been reported many times, experimental verification of the key factors that determine the rate of cadmium accumulation is lacking. We investigated the cadmium assimilation rate in the common wolf spider Pirata piraticus fed with contaminated fruit flies. Spiders were fed for 42 days with contaminated flies, followed by a detoxicification period of 28 days. Every 14 days, a subsample of spiders and flies was taken for Cd determination. It was demonstrated that a high cadmium assimilation (69.5%) and an excretion rate approaching zero resulted in high Cd concentration factors. The results indicate the importance of spiders in cadmium biomagnification along critical pathways.

  13. Effect of selenite and selenate on plant uptake of cadmium by maize (zea mays)

    SciTech Connect

    Shanker, K.; Mishra, S.; Srivastava, S.

    1996-03-01

    Selenium has been reported to confer tolerance to toxicity of heavy metals including cadmium, a highly toxic and non essential heavy metal, which enters the food chain via plant uptake from soils. Selenium reduces availability of cadmium to plants along with other aspects of its toxicokinetics. When plants are supplied with selenite, selenium concentrations in the xylem exudate are lower than selenate. Most of the selenate was transported as selenate and unidentified organic Se compounds. In contrast, Se distribution among various Se fractions within plants does not depend significantly on whether selenite or selenate was used. Selenium has a strong tendency to form complexes with heavy metals like Cd, Hg, Ag and Tl. It has been suggested that the protective effects of selenium are due to the formation of non toxic Se-metal complexes, although the mechanism by which this protective effect is exerted remains unclear. Studies on the effect of selenium (selenite) and cadmium additions to the soil on their concentrations in lettuce and wheat has indicated the role of selenite in reduction of cadmium uptake. The cletoxifying effect of sodium selenite on cadmium ion in the freshwater fish Potyacuthus cupanus has been reported. The discovery that an element like selenium counteracts the toxicity, chemical carcinogenesis and reduces the plant uptake of other toxic metals, highlights the possibility of existence of a Se-metal interaction mechanism in soil plant systems. The uptake and translocation of root-absorbed chromium supplied through irrigation in the trivalent and hexavalant states in various parts of the onion plant (Allium cepa) grown in soil and sand culture has been recently reported by us. In continuation of that, this preliminary report describes the effect of selenite and selenate pretreatment on the uptake of cadmium in the maize plant (Zea mays).

  14. Histopathological changes in relation to cadmium concentration in horse kidneys

    SciTech Connect

    Elinder, C.G.; Jonsson, L.; Piscator, M.; Rahnster, B.

    1981-10-01

    Histopathological changes in kidney cortex, as observed by light microscopy, are related to cadmium concentration in kidney cortex from 69 normal Swedish horses. Cadmium concentrations in kidney ranged from 11 to 186 ..mu..g Cd/g wet wt with an average of 60 ..mu..g Cd/g, which is considerably higher than those normally found in humans. The microscopical changes were rated and related to cadmium concentrations in kidneys by dose-response curves. A relationship existed between frequency of morphological changes and cadmium concentration in the renal cortex. There was no obvious relationship between age and frequency of histopathological changes. This indicates that in horse kidneys morphological changes occur at cadmium concentrations which are lower than the tentative critical level for humans of 200 ..mu..g Cd/g. It is concluded that horses constitute a population at risk for environmental cadmium contamination.

  15. Historical perspectives on cadmium toxicology

    SciTech Connect

    Nordberg, Gunnar F.

    2009-08-01

    The first health effects of cadmium (Cd) were reported already in 1858. Respiratory and gastrointestinal symptoms occurred among persons using Cd-containing polishing agent. The first experimental toxicological studies are from 1919. Bone effects and proteinuria in humans were reported in the 1940's. After World War II, a bone disease with fractures and severe pain, the itai-itai disease, a form of Cd-induced renal osteomalacia, was identified in Japan. Subsequently, the toxicokinetics and toxicodynamics of Cd were described including its binding to the protein metallothionein. International warnings of health risks from Cd-pollution were issued in the 1970's. Reproductive and carcinogenic effects were studied at an early stage, but a quantitative assessment of these effects in humans is still subject to considerable uncertainty. The World Health Organization in its International Program on Chemical Safety, WHO/IPCS (1992) (Cadmium. Environmental Health Criteria Document 134, IPCS. WHO, Geneva, 1-280.) identified renal dysfunction as the critical effect and a crude quantitative evaluation was presented. In the 1990's and 2000 several epidemiological studies have reported adverse health effects, sometimes at low environmental exposures to Cd, in population groups in Japan, China, Europe and USA (reviewed in other contributions to the present volume). The early identification of an important role of metallothionein in cadmium toxicology formed the basis for recent studies using biomarkers of susceptibility to development of Cd-related renal dysfunction such as gene expression of metallothionein in peripheral lymphocytes and autoantibodies against metallothionein in blood plasma. Findings in these studies indicate that very low exposure levels to cadmium may give rise to renal dysfunction among sensitive subgroups of human populations such as persons with diabetes.

  16. First-principles study of the mechanical properties of NiAl microalloyed by M (Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd)

    NASA Astrophysics Data System (ADS)

    Zhang, Caili; Han, Peide; Li, Jinmin; Chi, Mei; Yan, Lingyun; Liu, Yanping; Liu, Xuguang; Xu, Bingshe

    2008-05-01

    Structural, electronic and elastic properties for NiAl with 4d alloying elements M (Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd) have been studied using the first-principles pseudopotential density functional method within a generalized gradient approximation. From the elastic constants, C11, C12, C44, bulk modulus B0, Young's modulus E, the shear modulus G, the ratios of shear modulus to bulk modulus G/B0, negative Cauchy pressure parameter (C12 - C44) and Poisson's ratio ν calculated after structural full relaxation, M (Tc, Ru, Rh, Pd) alloying addition in NiAl has been shown to increase the stiffness of NiAl and improve its ductility. The density of states and charge density contour involving alloying additions of Ru were further investigated to clarify the electronic causes of the alloying additions.

  17. Fluorometric selective detection of fluoride ions in aqueous media using Ag doped CdS/ZnS core/shell nanoparticles.

    PubMed

    Boxi, Siddhartha Sankar; Paria, Santanu

    2016-01-14

    The presence of fluoride ions in drinking water plays an important role in human health. For that reason, maintaining the optimum concentration of fluoride ions in drinking water is essential, as both low and excess (above the permissible level) concentrations can cause different health problems, such as fluorosis, urolithiasis, kidney failure, cancer, and can even lead to death. So, development of a simple and low cost method for the detection of fluoride ions in water is highly desirable. In this study, a fluorometric method based on Ag-CdS/Ag-ZnS core/shell nanoparticles is developed for fluoride ion detection. The method was tested in aqueous solution at different pH values. The selectivity and sensitivity of the fluorescence probe was checked in the presence of other anions (Cl(-), Br(-), I(-), NO3(-) SO4(2-), HCO3(-), HPO4(2-), CH3COO(-), and H2PO4(-)) and found there is no significant interference of these associated ions. The fluoride ion concentration was varied in the range 190-22 800 μg L(-1) and a lower detection limit was obtained as 99.7 μg L(-1).

  18. Photocatalytic removal of M(2+) (Ni(2+), Cu(2+), Zn(2+), Cd(2+), Hg(2+) and Ag(+)) over new catalyst CuCrO(2).

    PubMed

    Ketir, W; Bouguelia, A; Trari, M

    2008-10-30

    The metal ions M(2+) (Ni(2+), Cu(2+), Zn(2+), Cd(2+), Hg(2+) and Ag(+)) are potentially toxic. Their electro deposition has been carried out in aqueous air-equilibrated CuCrO(2) suspension upon visible illumination. The delafossite CuCrO(2) is p-type semiconductor characterized by a low band gap (1.28 eV) and a long-term chemical stability. The corrosion rate is found to be 10(-2) micromol m(-2)month(-1) in aqua regia. The oxide has been elaborated through nitrate route where the specific surface area is increased via the surface/bulk ratio. A correlation exists between the dark M(2+) adsorption, the redox potential of M(2+/0) couple and the conduction band of CuCrO(2) positioned at -1.06 V(SCE). Ag(+) cannot be photoreduced because of its positive potential located far above the valence band. By contrast, Zn(2+) is efficiently deposited due to the large driving force at the interface. The improved photoactivity of copper with a deposition percentage (90%) is attributed to the strong dark adsorption onto the surface catalyst. The results indicate a competitive effect with the water reduction; it has been observed that the M(2+) deposition goes parallel with the hydrogen evolution. Such behavior is attributed to the low H(2) over voltage when ultra fine aggregate of M islands are photodeposited onto CuCrO(2) substrate.

  19. Characteristics of cadmium remobilization in tributary sediments in Three Gorges Reservoir using chemical sequential extraction and DGT technology.

    PubMed

    Xu, Dongyu; Gao, Bo; Gao, Li; Zhou, Huaidong; Zhao, Xingjuan; Yin, Shuhua

    2016-11-01

    The Three Gorges Reservoir (TGR) is the largest reservoir in China. Cadmium (Cd) is a primary pollutant in the TGR, and its speciation and bioavailability have attracted extensive attention since TGR submergence. In this study, Chelex-100 DGT (diffusive gradient in thin films) and the sequential extraction method were used to investigate the bioavailable Cd in sediments obtained from a typical tributary (Meixi) and mainstream (Yangtze) in the TGR. The total Cd concentrations in sediments of the four stations were also determined. In comparison to the concentrations of labile Cd measured by DGT (CDGT-Cd) in four profiles, CJ and MX-upstream/downstream were at potential risk for Cd release from surface sediments using the apparent diffusion flux across the interface numerical model. The order of CDGT-Cd in surface sediments was as follows: CJ > MX-downstream > MX-upstream > MX-midstream. Additionally, a positive correlation was demonstrated between CDGT-Cd and Cd in the exchangeable fraction (F1) in the surface sediments, indicating that Cd in the exchangeable fraction was readily captured by DGT. A negative correlation was observed between CDGT-Cd and CDGT-Fe, CDGT-Mn in the sediment-water-interface (SWI), suggesting that Fe/Mn oxides did not control the release of labile-Cd from sediments. Furthermore, a positive correlation existed between the CDGT-Cd in the surface sediments and Cd in the oxidizable fraction (F3), illustrating that Cd sorbed or bound with organic matter or sulfide was labile and released into the water phase from the surface sediments. A dark area was found in the AgI gel, which further demonstrated that Cd simultaneously was released with sulfide in this area.

  20. RISK ASSESSMENT AND MANAGEMENT OF ENVIRONMENTAL CADMIUM

    EPA Science Inventory


    Cadmium consumed in foods grown on soils contaminated by industrial Cd+Zn discharge has caused renal tubular dysfunction in
    exposed humans in discrete situations. However, lack of understanding about environmental Cd has caused wide concern that general
    populations may...

  1. Tolerance development to cadmium-induced alteration of drug action.

    PubMed

    Roberts, S A; Miya, T S; Schnell, R C

    1976-05-01

    Cadmium administration potentiates the duration of hexobarbital-induced hypnosis and inhibits the rate of hepatic microsomal metabolism of this drug in the male rat. The threshold dose of cadmium required to produce these alterations in drug action is 0.84 mg Ck/kg. If subthreshold doses of cadmium (0.21 or 0.42 mg Cd/kg) are administered prior to the 0.84 mg Cd/kg dose, the cadmium-induced alterations in drug action are no longer observed.

  2. The new insights into cadmium sensing

    PubMed Central

    Chmielowska-Bąk, Jagna; Gzyl, Jarosław; Rucińska-Sobkowiak, Renata; Arasimowicz-Jelonek, Magdalena; Deckert, Joanna

    2014-01-01

    Cadmium (Cd) is non-essential heavy metal, which in excess, exhibits deleterious effects to the most of the organisms. Mobilization of defense mechanisms against this toxic agent requires rapid activation of signaling pathways. The article presents recent advances in the research concerning cadmium signal transduction in plants. New insights into the involvement of reactive oxygen species (ROS), nitric oxide (NO), plant growth regulators, and Cd-induced protein modifications are reviewed. Moreover, the role of recently recognized Cd-associated signal elements, including micro RNAs and several cis- and trans-acting elements is discussed. PMID:24917871

  3. Strain differences in toxicity of oral cadmium intake in rats.

    PubMed

    Ninkov, Marina; Popov Aleksandrov, Aleksandra; Mirkov, Ivana; Demenesku, Jelena; Mileusnic, Dina; Jovanovic Stojanov, Sofija; Golic, Natasa; Tolinacki, Maja; Zolotarevski, Lidija; Kataranovski, Dragan; Brceski, Ilija; Kataranovski, Milena

    2016-10-01

    Influence of genetic background on toxicity of oral cadmium (Cd) administration (30 days, in drinking water; 5 ppm and 50 ppm of cadmium) was examined in Albino Oxford (AO) and Dark Agouti (DA) rats. Similar cadmium deposition was noted in gut and draining mesenteric lymph nodes (MLN) of both strains but intensity and/or the pattern of responses to cadmium in these tissues differ. Less intense intestinal damage and leukocyte infiltration was observed in gut of cadmium-exposed AO rats. While gut-associated lymph node cells of DA rats responded to cadmium with an increase of cell proliferation, oxidative activity, IFN-γ, IL-17 production and expression, no changes of these activities of MLN cells of cadmium-treated AO rats were observed. Spleen, which accumulated cadmium comparable to MLN, responded to metal by drop in cell viability and by reduced responsiveness of proliferation and cytokine production to stimulation in DA rats solely, which suggest tissue dependence of cadmium effects. More pronounced cadmium effects on MLN and spleen cells of DA rats (which accumulated similar cadmium doses as AO rats), showed greater susceptibility of this strain to cadmium. The results presented, for the first time, depict the influence of genetic background to effects of oral cadmium administration.

  4. Metallothionein protection of cadmium toxicity

    SciTech Connect

    Klaassen, Curtis D. Liu, Jie; Diwan, Bhalchandra A.

    2009-08-01

    The discovery of the cadmium (Cd)-binding protein from horse kidney in 1957 marked the birth of research on this low-molecular weight, cysteine-rich protein called metallothionein (MT) in Cd toxicology. MT plays minimal roles in the gastrointestinal absorption of Cd, but MT plays important roles in Cd retention in tissues and dramatically decreases biliary excretion of Cd. Cd-bound to MT is responsible for Cd accumulation in tissues and the long biological half-life of Cd in the body. Induction of MT protects against acute Cd-induced lethality, as well as acute toxicity to the liver and lung. Intracellular MT also plays important roles in ameliorating Cd toxicity following prolonged exposures, particularly chronic Cd-induced nephrotoxicity, osteotoxicity, and toxicity to the lung, liver, and immune system. There is an association between human and rodent Cd exposure and prostate cancers, especially in the portions where MT is poorly expressed. MT expression in Cd-induced tumors varies depending on the type and the stage of tumor development. For instance, high levels of MT are detected in Cd-induced sarcomas at the injection site, whereas the sarcoma metastases are devoid of MT. The use of MT-transgenic and MT-null mice has greatly helped define the role of MT in Cd toxicology, with the MT-null mice being hypersensitive and MT-transgenic mice resistant to Cd toxicity. Thus, MT is critical for protecting human health from Cd toxicity. There are large individual variations in MT expression, which might in turn predispose some people to Cd toxicity.

  5. Accumulation of cadmium from the dissolved and particulate phases by the freshwater mussel, Elliptio complanata

    SciTech Connect

    Yankovich, T.

    1995-12-31

    The primary objective of the current study was to quantify cadmium accumulation by Elliptio complanata from suspended particulates relative to the dissolved phase. Results obtained from this study suggest that particle physico-chemical properties and their associated cadmium concentrations may play a role in cadmium bioaccumulation by E. complanata. This accumulation of cadmium is due to direct uptake from the particulate phase and/or accumulation of dissolved cadmium which has leached off particles. The importance of the particulate phase in cadmium uptake is related to the type of particle to which mussels are exposed. No significant cadmium bioaccumulation was observed when mussels consumed Cd-contaminated kaolinite or illite clay particles. Significant uptake was observed by mussels exposed to Cd-contaminated montmorillonite clay particles at high bound cadmium levels; however, the dissolved phase accounted for all observed Cd accumulation, suggesting that equilibrium partitioning into the aqueous phase represented the key route of cadmium uptake from clay particles. Cadmium uptake did not occur when mussels were exposed to natural sediment particles containing low organic carbon concentrations, but significant bioaccumulation was observed when mussels consumed Cd-contaminated sediments with relatively high organic carbon contents. Dissolved cadmium concentrations present in sediment suspensions with low and high organic carbon contents were similar, suggesting that the particulate phase was the source of cadmium uptake. These results indicate that particle processing and selective feeding behaviors by filter-feeding bivalves may play a key role in determining the relative importance of dissolved and particulate phases in cadmium bioaccumulation.

  6. Field Evidence of Cadmium Phytoavailability Decreased Effectively by Rape Straw and/or Red Mud with Zinc Sulphate in a Cd-Contaminated Calcareous Soil

    PubMed Central

    Li, Bo; Yang, Junxing; Wei, Dongpu; Chen, Shibao; Li, Jumei; Ma, Yibing

    2014-01-01

    To reduce Cd phytoavailability in calcareous soils, the effects of soil amendments of red mud, rape straw, and corn straw in combination with zinc fertilization on Cd extractability and phytoavailability to spinach, tomato, Chinese cabbage and radish were investigated in a calcareous soil with added Cd at 1.5 mg kg−1. The results showed that water soluble and exchangeable Cd in soils was significantly decreased by the amendments themselves from 26% to 70%, which resulted in marked decrease by approximately from 34% to 77% in Cd concentration in vegetables. The amendments plus Zn fertilization further decreased the Cd concentration in vegetables. Also cruciferous rape straw was more effective than gramineous corn straw. In all treatments, rape straw plus red mud combined with Zn fertilization was most effective in decreasing Cd phytoavailability in soils, and it is potential to be an efficient and cost-effective measure to ensure food safety for vegetable production in mildly Cd-contaminated calcareous soils. PMID:25303439

  7. The Magic-Size Nanocluster (CdSe)34 as a Low-Temperature Nucleant for Cadmium Selenide Nanocrystals; Room-Temperature Growth of Crystalline Quantum Platelets.

    PubMed

    Wang, Yuanyuan; Zhang, Ying; Wang, Fudong; Giblin, Daryl E; Hoy, Jessica; Rohrs, Henry W; Loomis, Richard A; Buhro, William E

    2014-04-08

    Reaction of Cd(OAc)2·2H2O and selenourea in primary-amine/secondary-amine cosolvent mixtures affords crystalline CdSe quantum platelets at room temperature. Their crystallinity is established by X-ray diffraction analysis (XRD), high-resolution transmission electron microscopy (TEM), and their sharp extinction and photoluminescence spectra. Reaction monitoring establishes the magic-size nanocluster (CdSe)34 to be a key intermediate in the growth process, which converts to CdSe quantum platelets by first-order kinetics with no induction period. The results are interpreted to indicate that the critical crystal-nucleus size for CdSe under these conditions is in the range of (CdSe)34 to (CdSe)68. The nanocluster is obtained in isolated form as [(CdSe)34(n-octylamine)16(di-n-pentylamine)2], which is proposed to function as crystal nuclei that may be stored in a bottle.

  8. Cadmium in blood as an indicator of integrated exposure to cadmium in the urban population

    SciTech Connect

    Telisman, S.; Azaric, J.; Prpic-Majic, D.

    1986-04-01

    The concentration of cadmium in blood (CdB) is generally regarded as the best biological indicator of recent exposure to cadmium. However, since cadmium is a cumulative toxic agent with a biological half-life in the human body of about 20 years, it is not clear to what extent the CdB level reflects the body burden and recent exposure in conditions of low exposure to cadmium in the general population. The influence of duration of exposure to cadmium on the CdB level was examined in teachers and school children who attend the same schools and live in the same urban area of Zagreb. The results have shown 2.5-3 times higher CdB levels in adult nonsmokers as compared to children. Since the current environmental exposure to cadmium can be regarded as being comparable in the two groups, it appears that more than 60% of the CdB level in adults (nonsmokers) could be attributed to the influence of the body burden.

  9. Cadmium chloride treatment of rats significantly impairs membrane integrity of mesenchymal stem cells via electrolyte imbalance and lipid peroxidation, a possible explanation of Cd related osteoporosis

    PubMed Central

    Abnosi, Mohammad Husein; Golami, Someyeh

    2017-01-01

    Objective(s): Bone marrow mesenchymal stem cells (MSCs) play an important role in bone health. Cadmium causes osteoporosis, but the exact mechanisms of its effect on MSCs are not known. Materials and Methods: Rats were treated with cadmium chloride (40 mg/l) in drinking water for six weeks, and then the biochemical and morphological studies on MSCs were carried out as a cellular backup for osteoblasts. Viability and proliferation properties of the cells were evaluated using MTT assay, trypan blue, population doubling number, and colony forming assay. Morphology of the cells and biochemical parameters including activity of metabolic (ALP, AST, and ALT) and antioxidant enzymes (SOD, CAT, and POX) as well as the MDA level (as an indication of lipid peroxidation) were investigated. In addition, intracellular calcium, potassium, and sodium content were estimated. Data was analyzed statistically and P<0.05 was taken as the level of significance. Results: The results showed a significant reduction in viability and proliferation ability of extracted cells when compared to the controls. In addition, it was revealed that the cadmium treatment of rats caused a significant reduction in nuclear diameter and cytoplasm area. Also, there was significant increase in (ALT) and (AST) activity and intracellular calcium and potassium content but no change was observed with sodium content and ALP activity. The results showed [a] significant reduction in the antioxidant enzyme activity and increases in the MDA level. Conclusion: Based on the present study, reduction of viability and proliferation ability of MSCs might be a causative factor of osteoporosis in industrial areas. PMID:28392900

  10. Speciation and mobility of cadmium in straw and wood combustion fly ash.

    PubMed

    Hansen, H K; Pedersen, A J; Ottosen, L M; Villumsen, A

    2001-10-01

    Two fly ashes from biomass combustion have been analysed regarding cadmium speciation and mobility. A fly ash from straw combustion contained 10 mg Cd/kg dry matter, and around 50% of the cadmium was leachable in water. The possible main speciation of cadmium in this fly ash was CdCl2. When adding this fly ash to agricultural soil a threat for groundwater contamination and plant uptake is existing. A fly ash from wood chip combustion had 28.6 mg Cd/kg dry matter. In this fly ash, the cadmium was bound more heavily, with only small amounts of cadmium leached in mild extractants. A possible speciation of cadmium in this fly ash was as oxide or as CdSiO3. Long-term effects and accumulation of cadmium could be a problem when adding this fly ash to agricultural or forest soils.

  11. Identification of three relationships linking cadmium accumulation to cadmium tolerance and zinc and citrate accumulation in lettuce.

    PubMed

    Zorrig, Walid; Rouached, Aïda; Shahzad, Zaigham; Abdelly, Chedly; Davidian, Jean-Claude; Berthomieu, Pierre

    2010-10-15

    Lettuce (Lactuca sativa) is a plant species that shows high accumulation of cadmium, a toxic heavy metal. Lettuce is therefore a good model both for identifying determinants controlling cadmium accumulation in plant tissues and for developing breeding strategies aimed at limiting cadmium accumulation in edible tissues. In this work, 14-day-old plants from three lettuce varieties were grown for 8 days on media supplemented with cadmium concentrations ranging from 0 to 50 microM. Growth, as well as Cd(2+), Zn(2+), K(+), Ca(2+), NO(3)(-), SO(4)(2-), Cl(-), phosphate, malate and citrate root an shoot contents were analyzed. The three lettuce varieties Paris Island Cos, Red Salad Bowl and Kordaat displayed differential abilities to accumulate cadmium in roots and shoots, Paris Island Cos displaying the lowest cadmium content and Kordaat the highest. From the global analysis of the three varieties, three main trends were identified. First, a common negative correlation linked cadmium tissue content and relative dry weight reduction in response to cadmium treatments in the three varieties. Second, increasing cadmium concentration in the culture medium resulted in a parallel increase in zinc tissue content in all lettuce varieties. A common strong positive correlation between cadmium and zinc contents was observed for all varieties. This suggested that systems enabling zinc and cadmium transport were induced by cadmium. Finally, the cadmium treatments had a contrasting effect on anion contents in tissues. Interestingly, citrate content in shoots was correlated with cadmium translocation from roots to shoots, suggesting that citrate might play a role in cadmium transport in the xylem vessels. Altogether, these results shed light on three main strategies developed by lettuce to cope with cadmium, which could help to develop breeding strategies aimed at limiting cadmium accumulation in lettuce.

  12. 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

    PubMed Central

    Cassim, Naseem; Schnippel, Kathryn; Coetzee, Lindi Marie

    2017-01-01

    Introduction Cryptococcal meningitis is a major cause of mortality and morbidity in countries with high HIV prevalence, primarily affecting patients whose CD4 are < = 100 cells/μl. Routine Cryptococcal Antigen (CrAg) screening is thus recommended in the South African HIV treatment guidelines for all patients with CD4 counts < = 100 cells/μl, followed by pre-emptive anti-fungal therapy where CrAg results are positive. A laboratory-based reflexed CrAg screening approach, using a Lateral Flow Assay (LFA) on remnant EDTA CD4 blood samples, was piloted at three CD4 laboratories. Objectives This study aimed to assess the cost-per-result of laboratory-based reflexed CrAg screening at one pilot CD4 referral laboratory. Methods CD4 test volumes from 2014 were extracted to estimate percentage of CD4 < = 100 cells/μl. Daily average volumes were derived, assuming 12 months 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%). Results The pilot CD4 laboratory performed 267000 CD4 tests in 2014; ~ 9.3% (27500) reported CD4< = 100 cells/μl, equivalent to 106 CrAg tests performed daily. A batch of 30-tests could be performed in 1.6 hours, including preparation and analysis time. A cost-per-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 (<1%) respectively. One-way sensitivity analyses including increasing or decreasing test volumes by 60% revealed a cost-per-result range

  13. Intracellular sequestration of zinc, cadmium and silver in Hebeloma mesophaeum and characterization of its metallothionein genes.

    PubMed

    Sácký, Jan; Leonhardt, Tereza; Borovička, Jan; Gryndler, Milan; Briksí, Aleš; Kotrba, Pavel

    2014-06-01

    Sequestration of intracellular heavy metals in eukaryotes involves compartmentalization and binding with cytosolic, cysteine-rich metallothionein (MT) peptides. We examined the roles of these processes in handling of zinc (Zn), cadmium (Cd) and silver (Ag) in sporocarps and a metal-exposed extraradical mycelium of Hebeloma mesophaeum, the Zn-accumulating ectomycorrhizal (EM) species frequently associated with metal disturbed sites. Size exclusion chromatography revealed that the majority of Zn and Cd in the sporocarps and mycelium was contained in a low molecular mass fraction attributable to compartmentalized metal. The staining of hyphal cells with the Zn-specific Zinquin and Cd-specific Leadmium fluorescent tracers labeled Zn and Cd in small, punctuated vesicles and vacuoles, respectively. By contrast, the sporocarp and mycelium Ag was associated with cysteine-rich, 5-kDa peptides. The peptides of the same size were also identified in minor Zn and Cd complexes from the metal-exposed mycelium. We have further isolated and characterized HmMT1, HmMT2 and HmMT3 genes coding for different 5-kDa MTs of H. mesophaeum collected at a lead smelter site. Heterologous complementation assays in metal-sensitive yeast mutants indicated that HmMTs encode functional, metal-specific peptides: only HmMT1 was able to complement sensitivity to Zn; HmMT1 conferred higher tolerance to Cd and Cu than HmMT2 or HmMT3; and both HmMT2 and HmMT3, but not HmMT1, conferred increased tolerance to Ag. The presence of HmMT1 and HmMT3, but not HmMT2, was also confirmed in a H. mesophaeum isolate from an unpolluted site. Gene expression analysis in the extraradical mycelium of this isolate revealed that the transcription of HmMT1 was preferentially induced in the presence of Zn and Cd, while Ag was a stronger inducer of HmMT3. Altogether, these results improve our understanding of the handling of intracellular Zn, Cd and Ag in Hebeloma and represent the first evidence suggesting involvement of MTs

  14. Effects of warming on uptake and translocation of cadmium (Cd) and copper (Cu) in a contaminated soil-rice system under Free Air Temperature Increase (FATI).

    PubMed

    Ge, Li-Qiang; Cang, Long; Liu, Hui; Zhou, Dong-Mei

    2016-07-01

    Global warming has received growing attentions about its potential threats to human in recent, however little is known about its effects on transfer of heavy metals in agro-ecosystem, especially for Cd in rice. Pot experiments were conducted to evaluate Cd/Cu translocation in a contaminated soil-rice system under Free Air Temperature Increase (FATI). The results showed that warming gradually decreased soil porewater pH and increased water-soluble Cd/Cu concentration, reduced formation of iron plaque on root surface, and thus significantly increased total uptake of Cd/Cu by rice. Subsequently, warming significantly promoted Cd translocation from root to shoot, and increased Cd distribution percentage in shoot, while Cu was not significantly affected. Enhanced Cd uptake and translocation synergistically resulted in higher rice grain contamination with increasing concentration from 0.27 to 0.65 and 0.14-0.40 mg kg(-1) for Indica and Japonica rice, respectively. However increase of Cu in brown grain was only attributed to its uptake enhancement under warming. Our study provides a new understanding about the food production insecurity of heavy metal contaminated soil under the future global warming.

  15. Comparative proteome analysis of high and low cadmium accumulating soybeans under cadmium stress.

    PubMed

    Hossain, Zahed; Hajika, Makita; Komatsu, Setsuko

    2012-12-01

    A comparative proteomic study was performed to unravel the protein networks involved in cadmium stress response in soybean. Ten-day-old seedlings of contrasting cadmium accumulating soybean cultivars-Harosoy (high cadmium accumulator), Fukuyutaka (low cadmium accumulator), and their recombinant inbred line CDH-80 (high cadmium accumulator) were exposed to 100 μM CdCl(2) treatment for 3 days. Root growth was found to be affected under cadmium stress in all. Varietal differences at root protein level were evaluated. NADP-dependent alkenal double bond reductase P1 was found to be more abundant in low cadmium accumulating Fukuyutaka. Leaf proteome analysis revealed that differentially expressed proteins were primarily involved in metabolism and energy production. The results indicate that both high and low cadmium accumulating cultivars and CDH-80 share some common defense strategies to cope with the cadmium stress. High abundance of enzymes involved in glycolysis and TCA cycle might help cadmium challenged cells to produce more energy necessary to meet the high energy demand. Moreover, enhanced expressions of photosynthesis related proteins indicate quick utilization of photoassimilates in energy generation. Increased abundance of glutamine synthetase in all might be involved in phytochelatin mediated detoxification of cadmium ions. In addition, increased abundance of antioxidant enzymes, namely superoxide dismutase, ascorbate peroxidase, catalase, ensures cellular protection from reactive oxygen species mediated damages under cadmium stress. Enhanced expression of molecular chaperones in high cadmium accumulating cultivar might be another additional defense mechanism for refolding of misfolded proteins and to stabilize protein structure and function, thus maintain cellular homeostasis.

  16. Interaction of cadmium with phosphate on goethite

    SciTech Connect

    Venema, P.; Hiemstra, T.; Riemsdijk, W.H. van

    1997-08-01

    Interactions between different ions are of importance in understanding chemical processes in natural systems. In this study simultaneous adsorption of phosphate and cadmium on goethite is studied in detail. The charge distribution (CD)-multisite complexation (MUSIC) model has been successful in describing extended data sets of cadmium adsorption and phosphate adsorption on goethite. In this study, the parameters of this model for these two data sets were combined to describe a new data set of simultaneous adsorption of cadmium and phosphate on goethite. Attention is focused on the surface speciation of cadmium. With the extra information that can be obtained from the interaction experiments, the cadmium adsorption model is refined. For a perfect description of the data, the singly coordinated surface groups at the 110 face of goethite were assumed to form both monodentate and bidentate surface species with cadmium. The CD-MUSIC model is able to describe data sets of both simultaneous and single adsorption of cadmium and phosphate with the same parameters. The model calculations confirmed the idea that only singly coordinated surface groups are reactive for specific ion binding.

  17. Metal ion displacements in noncentrosymmetric chalcogenides La3Ga1.67S7, La3Ag0.6GaCh7 (Ch=S, Se), and La3MGaSe7 (M=Zn, Cd)

    NASA Astrophysics Data System (ADS)

    Iyer, Abishek K.; Yin, Wenlong; Rudyk, Brent W.; Lin, Xinsong; Nilges, Tom; Mar, Arthur

    2016-11-01

    The quaternary Ga-containing chalcogenides La3Ag0.6GaS7, La3Ag0.6GaSe7, La3ZnGaSe7, and La3CdGaSe7, as well as the related ternary chalcogenide La3Ga1.67S7, were prepared by reactions of the elements at 950 °C. They adopt noncentrosymmetric hexagonal structures (space group P63, 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 La3M1-xGaCh7 (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 (La3Ag0.6GaS7, La3Ag0.6GaSe7) as a response to overbonding. X-ray photoelectron spectroscopy supports the presence of monovalent Ag atoms in these compounds, which are not charge-balanced.

  18. A novel three-dimensional CdII metal-organic framework based on [Cd6(malonate)6] metallomacrocycles with zeolite SOD (sodalite) topology: poly[ammine-μ3-malonato-cadmium(II)].

    PubMed

    Yuan, Shuai; Liu, Mei-Jiao; Xie, Han-Yi; Xu, Meng-Zhen; Sun, Di

    2012-03-01

    A novel Cd(II) metal-organic framework, [Cd(C(3)H(2)O(4))(NH(3))](n), was synthesized by liquid diffusion conducted in the presence of ammonia. The Cd(II) atom has seven-coordinate O(6)N pentagonal-bipyramidal geometry. Six Cd(II) centers are joined by six malonate ligands to form an S(6)-symmetric [Cd(6)(malonate)(6)] metallomacrocycle, which is further extended through a side-on chelating malonate ligand to form a three-dimensional network. Topologically, each Cd(II) center is connected to four others to yield an infinite three-periodic four-coordinated SOD (sodalite) network with point symbol {4(2)·6(4)}. The overall network structure in the crystal is maintained and stabilized by the presence of N-H...O hydrogen bonds.

  19. Cadmium minimization in wheat: A critical review.

    PubMed

    Rizwan, Muhammad; Ali, Shafaqat; Abbas, Tahir; Zia-Ur-Rehman, Muhammad; Hannan, Fakhir; Keller, Catherine; Al-Wabel, Mohammad I; Ok, Yong Sik

    2016-08-01

    Cadmium (Cd) accumulation in wheat (Triticum aestivum L.) and its subsequent transfer to food chain is a major environmental issue worldwide. Understanding wheat response to Cd stress and its management for aiming to reduce Cd uptake and accumulation in wheat may help to improve wheat growth and grain quality. This paper reviewed the toxic effects, tolerance mechanisms, and management of Cd stress in wheat. It was concluded that Cd decreased germination, growth, mineral nutrients, photosynthesis and grain yield of wheat and plant response to Cd toxicity varies with cultivars, growth conditions and duration of stress applied. Cadmium caused oxidative stress and genotoxicity in wheat plants. Stimulation of antioxidant defense system, osmoregulation, ion homeostasis and over production of signalling molecules are important adaptive strategies of wheat under Cd stress. Exogenous application of plant growth regulators, inorganic amendments, proper fertilization, silicon, and organic, manures and biochar, amendments are commonly used for the reduction of Cd uptake in wheat. Selection of low Cd-accumulating wheat cultivars, crop rotation, soil type, and exogenous application of microbes are among the other agronomic practices successfully employed in reducing Cd uptake by wheat. These management practices could enhance wheat tolerance to Cd stress and reduce the transfer of Cd to the food chain. However, their long-term sustainability in reducing Cd uptake by wheat needs further assessment.

  20. Diffusion and Defect Characterization Studies of Mercury Cadmium Telluride

    DTIC Science & Technology

    1989-08-01

    Mercury Cadmium Telluride" Principal Investigator: D. A. Stevenson Department of Materials Science and Engineering Stanford University Stanford, CA 94305...Include Security Classificatton, Difuson Defect Characterization Studies of Mercury Cadmium Telluride 12 PERSONAL AUTHOR(S) ProfessJL Ddvid A. Stevenson 13a...diffusion and defect chemistry of mercury cadmium telluride (MCT; Hg Cd Te). In this study, we have measured tracer self- diffusion and interdiffusion

  1. Immunochromatographic assay of cadmium levels in oysters.

    PubMed

    Nishi, Kosuke; Kim, In-Hae; Itai, Takaaki; Sugahara, Takuya; Takeyama, Haruko; Ohkawa, Hideo

    2012-08-15

    Oysters are one of foodstuffs containing a relatively high amount of cadmium. Here we report on establishment of an immunochromatographic assay (ICA) method of cadmium levels in oysters. Cadmium was extracted with 0.l mol L(-1) HCl from oysters and cleaned up from other metals by the use of an anion-exchange column. The behavior of five metals Mn, Fe, Cu, Zn, and Cd was monitored at each step of extraction and clean-up procedure for the ICA method in an inductively coupled plasma-mass spectrometry (ICP-MS) analysis. The results revealed that a simple extraction method with the HCl solution was efficient enough to extract almost all of cadmium from oysters. Clean-up with an anion-exchange column presented almost no loss of cadmium adsorbed on the column and an efficient removal of metals other than cadmium. When a spiked recovery test was performed in the ICA method, the recovery ranged from 98% to 112% with relative standard deviations between 5.9% and 9.2%. The measured values of cadmium in various oyster samples in the ICA method were favorably correlated with those in ICP-MS analysis (r(2)=0.97). Overall results indicate that the ICA method established in the present study is an adequate and reliable detection method for cadmium levels in oysters.

  2. Cadmium concentrations in tobacco and tobacco smoke

    SciTech Connect

    Scherer, G.; Barkemeyer, H.

    1983-02-01

    The amount of cadmium in tobacco depends on the variety and origin of the plant as well as on the analytical method used to determine cadmium. In the literature, cadmium concentrations in tobacco of between 0.5 and 5 ppm are reported. Modern German cigarette tobacco contains about 0.5-1.5 micrograms cadmium/cigarette. Of importance for the smoker is the amount of the metal in the mainstream smoke. The cadmium level in the mainstream smoke of modern cigarettes is reduced by means of filters and other construction features. The average Cd value of German filter cigarettes is less than 0.1 microgram/cigarette in mainstream smoke. An average daily intake of about 1 microgram cadmium by smoking 20 cigarettes can be calculated on the basis of an experimentally proved pulmonary retention rate of 50%. Pulmonary resorption rates relevant to uptake rates of cadmium by smoking are discussed. It can be assumed that cadmium uptake by smoking modern cigarettes has been reduced because of modifications in tobacco processing and cigarette construction in the last few decades.

  3. Cadmium and Its Neurotoxic Effects

    PubMed Central

    Wang, Bo; Du, Yanli

    2013-01-01

    Cadmium (Cd) is a heavy metal that has received considerable concern environmentally and occupationally. Cd has a long biological half-life mainly due to its low rate of excretion from the body. Thus, prolonged exposure to Cd will cause toxic effect due to its accumulation over time in a variety of tissues, including kidneys, liver, central nervous system (CNS), and peripheral neuronal systems. Cd can be uptaken from the nasal mucosa or olfactory pathways into the peripheral and central neurons; for the latter, Cd can increase the blood brain barrier (BBB) permeability. However, mechanisms underlying Cd neurotoxicity remain not completely understood. Effect of Cd neurotransmitter, oxidative damage, interaction with other metals such as cobalt and zinc, estrogen-like, effect and epigenetic modification may all be the underlying mechanisms. Here, we review the in vitro and in vivo evidence of neurotoxic effects of Cd. The available finding indicates the neurotoxic effects of Cd that was associated with both biochemical changes of the cell and functional changes of central nervous system, suggesting that neurotoxic effects may play a role in the systemic toxic effects of the exposure to Cd, particularly the long-term exposure. PMID:23997854

  4. Improving the efficiency of ITO/nc-TiO2/CdS/P3HT:PCBM/PEDOT:PSS/Ag inverted solar cells by sensitizing TiO2 nanocrystalline film with chemical bath-deposited CdS quantum dots

    PubMed Central

    2013-01-01

    An improvement in the power conversion efficiency (PCE) of the inverted organic solar cell (ITO/nc-TiO2/P3HT:PCBM/PEDOT:PSS/Ag) is realized by depositing CdS quantum dots (QDs) on a nanocrystalline TiO2 (nc-TiO2) film as a light absorption material and an electron-selective material. The CdS QDs were deposited via a chemical bath deposition (CBD) method. Our results show that the best PCE of 3.37% for the ITO/nc-TiO2/CdS/P3HT:PCBM/PEDOT:PSS/Ag cell is about 1.13 times that (2.98%) of the cell without CdS QDs (i.e., ITO/nc-TiO2/P3HT:PCBM/PEDOT:PSS/Ag). The improved PCE can be mainly attributed to the increased light absorption and the reduced recombination of charge carriers from the TiO2 to the P3HT:PCBM film due to the introduced CdS QDs. PMID:24172258

  5. Improving the efficiency of ITO/nc-TiO2/CdS/P3HT:PCBM/PEDOT:PSS/Ag inverted solar cells by sensitizing TiO2 nanocrystalline film with chemical bath-deposited CdS quantum dots.

    PubMed

    Chen, Chong; Li, Fumin

    2013-10-31

    An improvement in the power conversion efficiency (PCE) of the inverted organic solar cell (ITO/nc-TiO2/P3HT:PCBM/PEDOT:PSS/Ag) is realized by depositing CdS quantum dots (QDs) on a nanocrystalline TiO2 (nc-TiO2) film as a light absorption material and an electron-selective material. The CdS QDs were deposited via a chemical bath deposition (CBD) method. Our results show that the best PCE of 3.37% for the ITO/nc-TiO2/CdS/P3HT:PCBM/PEDOT:PSS/Ag cell is about 1.13 times that (2.98%) of the cell without CdS QDs (i.e., ITO/nc-TiO2/P3HT:PCBM/PEDOT:PSS/Ag). The improved PCE can be mainly attributed to the increased light absorption and the reduced recombination of charge carriers from the TiO2 to the P3HT:PCBM film due to the introduced CdS QDs.

  6. Concentration of Cadmium in Cacao Beans and its Relationship with Soil Cadmium in Southern Ecuador

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The concentration of cadmium (Cd) in cacao (Theobroma cacao, L.) beans above a critical level (0.6 mg kg-1 established by the European Union) has raised concerns of safety in the consumption of cacao-based chocolate (dark chocolate). Currently, little is available regarding Cd concentration in soil,...

  7. Effects of increased pCO2 and temperature on trace element (Ag, Cd and Zn) bioaccumulation in the eggs of the common cuttlefish, Sepia officinalis

    NASA Astrophysics Data System (ADS)

    Lacoue-Labarthe, T.; Martin, S.; Oberhänsli, F.; Teyssié, J.-L.; Markich, S.; Jeffree, R.; Bustamante, P.

    2009-05-01

    Cephalopods play a key role in many marine trophic networks and constitute alternative fisheries resources, especially given the ongoing decline in finfish stocks. Along the European coast, the eggs of the cuttlefish Sepia officinalis are characterized by an increasing permeability of the eggshell during development, which leads to selective accumulation of essential and non-essential elements in the embryo. Temperature and pH are two critical factors that affect the metabolism of marine organisms in the coastal shallow waters. In this study, we are testing the effects of pH and temperature through a crossed (3×2) laboratory experiment. Seawater pH showed a strong effect on the egg weight and non-significant impact on the hatchlings weight at the end of development implying egg swelling process and embryo growth disturbances. The lower pH of incubation seawater of eggs, the more the hatchlings accumulated 110m Ag in their tissues. The 109Cd CF decreased with increasing pH and 65Zn CF reached the maximal values pH 7.85, independent of temperature. Our results suggest that pH and temperature affected both the permeability properties of the eggshell and the embryo metabolism. To the best of our knowledge, this is one of the first studies on the ocean acidification and ocean warming consequences on the metal uptake in marine organisms, stimulating further interest to evaluate the likely ecotoxicological impact of the global change on the early-life stage of the cuttlefish.

  8. Direct detection of Pb in urine and Cd, Pb, Cu, and Ag in natural waters using electrochemical sensors immobilized with DMSA functionalized magnetic nanoparticles

    SciTech Connect

    Yantasee, Wassana; Hongsirikarn, Kitiya; Warner, Cynthia L.; Choi, Daiwon; Sangvanich, Thanapon; Toloczko, Mychailo B.; Warner, Marvin G.; Fryxell, Glen E.; Addleman, Raymond S.; Timchalk, Chuck

    2008-03-01

    Urine is universally recognized as one of the best non-invasive matrices for biomonitoring exposure to a broad range of xenobiotics including toxic metals. For direct, simple, and field-deployable monitoring of urinary Pb, electrochemical sensors employing superparamagnetic iron oxide (Fe3O4) nanoparticles with a surface functionalization of dimercaptosuccinic acid (DMSA) has been developed. The metal detection involves rapid collection of dispersed metal-bound nanoparticles from a sample solution at a magnetic or electromagnetic electrode, followed by the stripping voltammetry of the metal in acidic medium. The sensors were evaluated as a function of solution pH, the binding affinity of Pb to DMSA-Fe3O4, the ratio of nanoparticles per sample volume, preconcentration time, and Pb concentrations. The effect of binding competitions between the DMSA-Fe3O4 and urine constituents for Pb on the sensor responses was studied. After 90s of preconcentration in samples containing 25 vol.% of rat urine and 0.1 g/L of DMSA-Fe3O4, the sensor could detect background level of Pb (< 1 ppb) and yielded linear responses from 0 to 50 ppb of Pb, excellent reproducibility (%R.S.D of 5.3 for seven measurements of 30 ppb Pb), and Pb concentrations comparable to those measured by ICP-MS. The sensor could also simultaneously detect background levels (< 1 ppb) of Cd, Pb, Cu, and Ag in river and seawater.

  9. Reaction of cadmium sulfoselenide with borosilicate glasses

    SciTech Connect

    Buler, P.I.; Zupnik, Z.M.; Perminov, A.A.; Dudina, I.A.

    1987-11-10

    In this work a study has been made of the reaction of CdSe, CdS, and pigment 1024 with borosilicate glasses in an air atmosphere at temperature of 773-1173/sup 0/K using a gravimetric method and x-ray diffraction. It was shown that the oxidation of the cadmium selenide is accompanied by a mass gain up to 1070/sup 0/K and begins at a temperature of 860/sup 0/K. X-ray diffractionanalysis of the cadmium selenide powder that had been held for 10 h at 973/sup 0/K showed that the reaction products include CdSeO/sub 3/. In the oxidation of a mixture of CdSe with the glass powder, the mass increase upon constant heating begins at a lower temperature (820/sup 0/K) than for pure CdSe.

  10. Direct examination of cadmium bonding in rat tissues dosed with mine wastes and cadmium-containing solutions

    NASA Astrophysics Data System (ADS)

    Diacomanolis, V.; Ng, J. C.; Sadler, R.; Harris, H. H.; Nomura, M.; Noller, B. N.

    2010-06-01

    Direct examination by XANES and EXAFS of metal bonding in tissue can be demonstrated by examining cadmium uptake and bonding in animal tissue maintained at cryogenic temperatures. XANES at the K-edge of cadmium were collected at the Photon Factory Advanced Ring (PF-AR), NW10A beam line at KEK-Tsukuba-Japan. Rats fed with 1g mine waste containing 8-400 mg/kg cadmium per 200g body weight (b.w.) or dosed by oral gavage with either cadmium chloride solution alone (at 6 mg/kg b.w.) or in combination with other salts (As, Cu or Zn), 5 days/week for 6 weeks, had 0.1-7.5 and 8-86 mg/kg cadmium in the liver or kidney, respectively. Rats given intraperitoneally (ip) or intravenously (iv) 1-4 times with 1 mg/kg b.w. cadmium solution had 30-120 mg/kg cadmium in the liver or kidney. Tissues from rats were kept and transferred at cryogenic temperature and XANES were recorded at 20 K. The spectra for rat liver samples suggested conjugation of cadmium with glutathione or association with the sulfide bond (Cd-S) of proteins and peptides. EXAFS of rat liver fed by Cd and Zn solutions showed that Cd was clearly bound to S ligands with an inter-atomic distance of 2.54 Å for Cd-S that was similar to cadmium sulfide with an inter-atomic distance of 2.52 Å for Cd-S. Liver or kidney of rats fed with mine wastes did not give an edge in the XANES spectra indicating little uptake of cadmium by the animals. Longer and higher dosing regimen may be required in order to observe the same Cd-S bond in the rat tissue from mine wastes, including confirmation by EXAFS.

  11. Ion conduction in the Ag{sub 2}HgI{sub 4}-Cu{sub 2}HgI{sub 4} systems doped with Cd{sup 2+}, K{sup +}, and Na{sup +}

    SciTech Connect

    Nair, S.M.; Yahya, A.I.; Ahmad, A.

    1996-03-01

    Ion conductivities of face centered cubic Ag{sub 2}HgI{sub 4}-Cu{sub 2}HgI{sub 4} systems doped with Cd{sup 2+}, K{sup +}, and Na{sup +} were measured. In 67 mol% Ag{sub 2}HgI{sub 4} solid solution doped with Cd{sup 2+} ions, the phase transition occurs at a lower temperature than in the parent compounds and the system shows higher conductivity. The increase in conductivity is discussed in terms of vacancies produced. K{sup +} doped Ag{sub 2}HgI{sub 4} exhibits higher conductivity prior to the phase transition, which is attributed to lattice loosening. A decrease in conductivity is observed above 140{degrees}C. This is interpreted in terms of anion framework collapse. Na{sup +} doped Ag{sub 2}HgI{sub 4} shows high conductivity for the high temperature phase because of the small size of Na{sup +} ions. The activation energy for ionic motion for all the samples is calculated from the graph of log({delta}T) versus 1/T.

  12. Cadmium levels in kidney cortex in Swedish farmers

    SciTech Connect

    Nilsson, U.; Schuetz, A.; Bensryd, I.; Nilsson, A.; Skerfving, S.; Mattsson, S.

    2000-01-01

    The cadmium levels in kidney cortex (K-Cd) did not differ statistically between 10 nonsmoking farmers from the south of Sweden, who had a high intake of locally produced food and who were affected by acid precipitation (as indicated by low pH in the drinking water from their private wells) and 10 farmers less affected. Neither did 10 farmers selected because of high blood cadmium (B-Cd) differ from 10 with low [medians: K-Cd, 15 vs 9 {micro}g/g; B-Cd, 2.6 vs 1.3 nmol/L (0.29 vs 0.14 {micro}g/L)]. In all 40 farmers, there was an increase of urinary cadmium levels (U-Cd) with decreasing drinking water pH. Further, K-Cd increased with rising B-Cd, and both B-Cd, and U-Cd rose with increasing age. Further, there was an association between U-Cd and B-Cd. The authors could not demonstrate with certainty any effect of the acid precipitation on the cadmium retention in the farmers, although the association between U-Cd and drinking water pH deserves further study.

  13. Cadmium in zinc deposits: Economic geology of a polluting element

    SciTech Connect

    Schwartz, M.O.

    2000-05-01

    The chief host of cadmium in zinc deposits is sphalerite, the cadmium content of which depends on the type of deposit. Sphalerite from Mississippi Valley-type (MVT) deposits has high cadmium concentrations whereas sphalerite from exhalative deposits has low cadmium concentrations. The Cd content of sphalerite depends on the Cd/Zn ratio, ligand activities, and temperature of the ore-forming fluids. The combined effect of variation of temperature, pH, total activity of reduced sulfur, and activity of Cl{sup {minus}} cannot by itself account for either Cd depletion (exhalative deposits) or Cd enrichment (MVT deposits). Variations in the Cd/Zn ratio of the fluid have a significant effect in determining that of sphalerite. Basinal brines, which can be considered to be the recent equivalents of MVT fluids, have high Cd/Zn ratios, and active exhalative systems are characterized by low Cd/Zn ratios. Probably the differences in sphalerite composition between the different deposit types are less a function of temperature and ligand activities than Cd/Zn ratio of the ore-forming fluids. In the hydrothermal environment, the Cd/Zn ratio is generally not high enough to allow crystallization of cadmium sulfides (greenockite or hawleyite). The abundance of greenockite in the supergene alteration zone of hydrothermal zinc deposits can be explained on the basis of Zn scavenging by crystallizing smithsonite.

  14. Influence of chemical and environmental stressors on acute cadmium toxicity

    SciTech Connect

    Baer, K.N.; Benson, W.H.

    1987-01-01

    Previous investigations have demonstrated that the cytosolic protein metallothionein (MT) is induced not only by exposure to certain heavy metals but also by a variety of other factors, including environmental stress. While MT synthesis has been observed with exposure to cold temperatures, there is a paucity of data concerning the influence of cold on heavy-metal toxicity. The present investigation focused on the influence of metal and cold pretreatments on the acute toxicity of cadmium. Mortalities of 80% and 100% were observed for mice orally administered challenge doses of 100 mg Cd/kg and 150 mg Cd/kg, respectively. To determine a protective cadmium pretreatment dose, animals were administered 2.5, 5, 10, 20, 25, and 50 mg Cd/kg 24 h prior to cadmium challenge. In animals pretreated with 10 mg Cd/kg, mortalities of 20% and 70% were observed with the respective challenge doses. Immediately following cold stress (4/sup 0/C, 12 h), mortalities of 30% and 90% were observed with cadmium challenge doses of 100 and 150 mg Cd/kg, respectively. Significant correlations were demonstrated between induced hepatic MT concentrations and cadmium pretreatment, as well as cold pretreatment. The induced tolerance to cadmium was attributed, in part, to the induction of MT synthesis. Furthermore, the induced levels of MT resulting from cold stress may confound the simplistic approach of using MT as a biological monitor of occupational exposure to cadmium.

  15. EFFECTS OF CADMIUM ON THE REPRODUCTIVE AXIS OF JAPANESE MEDAKA

    EPA Science Inventory

    Cadmium (Cd) is a ubquitous element and a significant inorganic pollutant that has previously been found to bioaccumulate in reproductive organs of fish and disrupt important endocrine processes, especially those involved in synthesis, release and metabolism of hormones. Clearly,...

  16. Chemical speciation of cadmium: an approach to evaluate plant-available cadmium in Ecuadorian soils under cacao production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Elevated concentration of cadmium (Cd) in cacao beans has raised serious concerns about the safety of chocolate consumption. Accumulation of Cd cacao bean in southern Ecuador has been reported to relate soil contamination. In this study, soil fractionation was conducted to identify available Cd poo...

  17. Formation of Defected Cadmium Ferrite during Hydrothermal Storage of Cadmium-Iron Hydroxides

    NASA Astrophysics Data System (ADS)

    Wolski, W.; Wolska, E.; Kaczmarek, J.

    1994-05-01

    The storage of amorphous coprecipitated Cd(OH) 2 · 2Fe(OH) 3 gel in mother liquor at 150 ± 2°C for 20 hr leads to a crystalline species which, according to X-ray analysis, is composed of cadmium hydroxide nitrate, Cd 3(OH) 5NO 3, cadmium hydroxide, βCd(OH) 2, and a strongly ferrimagnetic spinel phase. The Curie point at 270-280°C was found by thermomagnetic analysis. At that temperature the decomposition of the spinel phase and of the accompanying nonmagnetic phases takes place. IR spectra indicate that during thermomagnetic recording the liberated cadmium oxide and iron oxide form antiferromagnetic cadmium ferrite, with frequencies somewhat displaced in comparison to CdFe 2O 4 annealed at 1000°C. The results indicate that the ferrimagnetic phase (having spinel structure, a unit-cell parameter a of about 8.37 ± 0.01 Å, and a Tc point differing by more than 300°C from that of pure maghemite, γFe 2O 3) is likely to be a defected solid solution of maghemite and cadmium ferrite, of the formula Cd 2+xFe 3+1- x [Fe 3+(5+ x)/3 □ (1- x)/3 ]O 4.

  18. Cadmium binding by bacteria: screening and characterization of new isolates and mutants.

    PubMed

    Minz, D; Rosenberg, E; Ron, E Z

    1996-01-15

    A fast and simple methodology was developed that enables screening of microbial strains for their ability to bind cadmium. It is based on the use of a radioisotope of cadmium (109Cd) for screening colonies and for evaluation of cadmium binding. The methods described here can be used to screen new environmental isolates or to obtain mutants with altered ability to bind cadmium. Examples for the two uses are described in the paper.

  19. Effects of salinity, temperature, and cadmium stress on cadmium-binding protein in the grass shrimp, Palaemonetes pugio

    SciTech Connect

    Howard, C.L.

    1988-01-01

    In 96-hour bioassays, shrimp were exposed to zero or one of three levels of cadmium, under one of six different salinity and temperature regimes. CdBP concentrations were quantified in survivors from the 24 exposure groups. Salinity and temperature did not affect survivorship unless the shrimp were also exposed to cadmium. Grass shrimp were most sensitive to cadmium at low salinity-high temperature, and least sensitive at high salinity-low temperature. The incidence of cadmium-associated black lesions in gill tissue was influenced by salinity and temperature stress. P. pugio produced a 10,000 dalton metallothionein-like CdBP when exposed to at least 0.1 mg Cd{sup 2+}/L for 96 hours. Accumulation of CdBP was increased with increases in the exposure cadmium level, increases in temperature and decreases in salinity, independently and in conjunction with one another. Maximum CdBP concentrations occurred in grass shrimp that survived the salinity-temperature-cadmium conditions creating maximum stress as measured by highest mortality, not necessarily in shrimp exposed to the highest cadmium levels. The potential utility of this method as a monitor of physiological stress in estuarine biota inhabiting metal-polluted environments is discussed.

  20. Low-level cadmium exposure and effects on kidney function

    PubMed Central

    Wallin, Maria; Sallsten, Gerd; Lundh, Thomas; Barregard, Lars

    2014-01-01

    Objectives The nephrotoxicity of cadmium at low levels of exposure, measured by urinary cadmium, has recently been questioned since co-excretion of cadmium and proteins may have causes other than cadmium toxicity. The aim of this study was to explore the relation between kidney function and low or moderate cadmium levels, measured directly in kidney biopsies. Methods We analysed cadmium in kidney biopsies (K-Cd), blood (B-Cd) and urine (U-Cd) from 109 living kidney donors in a cross-sectional study. We measured glomerular filtration rate (GFR), cystatin C in serum, albumin, β-2-microglobulin (B2M), retinol-binding protein (RBP), α-1-microglobulin (A1M), N-acetyl-β-d-glucosaminidase and kidney injury molecule 1 (KIM-1) in 24 h and overnight urine. Results We found significant positive associations between A1M excretion and K-Cd in multiple regression models including age, sex, weight, smoking and urinary flow rate. This association was also present in never-smokers. A1M was also positively associated with B-Cd and U-Cd. GFR and the other biomarkers of kidney function were not associated with K-Cd. GFR estimated from serum cystatin C showed a very poor correlation with measured GFR. KIM-1, RBP and possibly albumin were positively associated with U-Cd, but only in overnight urine. No associations were found with B2M. Conclusions Our results suggest that A1M in urine is a sensitive biomarker for effects of low-level cadmium exposure. A few associations between other renal biomarkers and U-Cd, but not K-Cd, were probably caused by physiological co-excretion or chance. PMID:25286916

  1. Cadmium induces cadmium-tolerant gene expression in the filamentous fungus Trichoderma harzianum.

    PubMed

    Cacciola, Santa O; Puglisi, Ivana; Faedda, Roberto; Sanzaro, Vincenzo; Pane, Antonella; Lo Piero, Angela R; Evoli, Maria; Petrone, Goffredo

    2015-11-01

    The filamentous fungus Trichoderma harzianum, strain IMI 393899, was able to grow in the presence of the heavy metals cadmium and mercury. The main objective of this research was to study the molecular mechanisms underlying the tolerance of the fungus T. harzianum to cadmium. The suppression subtractive hybridization (SSH) method was used for the characterization of the genes of T. harzianum implicated in cadmium tolerance compared with those expressed in the response to the stress induced by mercury. Finally, the effects of cadmium exposure were also validated by measuring the expression levels of the putative genes coding for a glucose transporter, a plasma membrane ATPase, a Cd(2+)/Zn(2+) transporter protein and a two-component system sensor histidine kinase YcbA, by real-time-PCR. By using the aforementioned SSH strategy, it was possible to identify 108 differentially expressed genes of the strain IMI 393899 of T. harzianum grown in a mineral substrate with the addition of cadmium. The expressed sequence tags identified by SSH technique were encoding different genes that may be involved in different biological processes, including those associated to primary and secondary metabolism, intracellular transport, transcription factors, cell defence, signal transduction, DNA metabolism, cell growth and protein synthesis. Finally, the results show that in the mechanism of tolerance to cadmium a possible signal transduction pathway could activate a Cd(2+)/Zn(2+) transporter protein and/or a plasma membrane ATPase that could be involved in the compartmentalization of cadmium inside the cell.

  2. An amperometric chloramphenicol immunosensor based on cadmium sulfide nanoparticles modified-dendrimer bonded conducting polymer.

    PubMed

    Kim, Dong-Min; Rahman, Md Aminur; Do, Minh Hien; Ban, Changill; Shim, Yoon-Bo

    2010-03-15

    An amperometric chloramphenicol (CAP) immunosensor was fabricated by covalently immobilizing anti-chloramphenicol acetyl transferase (anti-CAT) antibody on cadmium sulfide nanoparticles (CdS) modified-dendrimer that was bonded to the conducting polymer (poly 5, 2': 5', 2''-terthiophene-3'-carboxyl acid (poly-TTCA)) layer. The AuNPs, dendrimers, and CdS nanoparticles were deposited onto the polymer layer in order to enhance the sensitivity of the sensor probes. The particle sizes were determined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The immobilization of dendrimers, CdS, and anti-CAT were confirmed using energy disruptive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and quartz crystal microbalance (QCM) techniques. The detection of CAP was based on the competitive immuno-interaction between the free- and labeled-CAP for active sites of the anti-CAT. Hydrazine was used as the label for CAP, and it electrochemically catalyzed the reduction of H(2)O(2) at -0.35 V vs. Ag/AgCl. Under optimized conditions, the proposed immunosensor exhibited a linear range of CAP detection between 50 pg/mL and 950 pg/mL, and the detection limit was 45 pg/mL. The immunosensor was examined in real meat samples for the analysis of CAP.

  3. Lead, cadmium and cobalt (Pb, Cd, and Co) leaching of glass-clay containers by pH effect of food.

    PubMed

    Valadez-Vega, Carmen; Zúñiga-Pérez, Clara; Quintanar-Gómez, Samuel; Morales-González, José A; Madrigal-Santillán, Eduardo; Villagómez-Ibarra, José Roberto; Sumaya-Martínez, María Teresa; García-Paredes, Juan Diego

    2011-01-01

    Recent studies have shown that handcrafted glass-clay containers are a health risk because they can be contaminated by heavy metals, which can be transferred to food, thus reaching the human body to potentially cause illness. Therefore, in the present work, we evaluate the leaching of lead, cadmium, and cobalt from glass-clay containers into two types of food: tomato sauce (salsa), and chickpea puree. The containers were obtained from four regions in the Mexican state of Hidalgo. Repetitive extractions from the containers were carried out to quantify the leaching of the heavy metals into the salsa, the chickpea puree, and acetic acid using the technique proposed by the USFDA. The results show that greater use of the containers leads to more leaching of heavy metals into both types of food and into the acetic acid, with the greatest metal extraction recorded for the Ixmiquilpan vessels. These results indicate that the metals present in the glass-clay containers leach into the food and that increased reuse increases the risk to the people who use them in food preparation.

  4. Lead, Cadmium and Cobalt (Pb, Cd, and Co) Leaching of Glass-Clay Containers by pH Effect of Food

    PubMed Central

    Valadez-Vega, Carmen; Zúñiga-Pérez, Clara; Quintanar-Gómez, Samuel; Morales-González, José A.; Madrigal-Santillán, Eduardo; Villagómez-Ibarra, José Roberto; Sumaya-Martínez, María Teresa; García-Paredes, Juan Diego

    2011-01-01

    Recent studies have shown that handcrafted glass-clay containers are a health risk because they can be contaminated by heavy metals, which can be transferred to food, thus reaching the human body to potentially cause illness. Therefore, in the present work, we evaluate the leaching of lead, cadmium, and cobalt from glass-clay containers into two types of food: tomato sauce (salsa), and chickpea puree. The containers were obtained from four regions in the Mexican state of Hidalgo. Repetitive extractions from the containers were carried out to quantify the leaching of the heavy metals into the salsa, the chickpea puree, and acetic acid using the technique proposed by the USFDA. The results show that greater use of the containers leads to more leaching of heavy metals into both types of food and into the acetic acid, with the greatest metal extraction recorded for the Ixmiquilpan vessels. These results indicate that the metals present in the glass-clay containers leach into the food and that increased reuse increases the risk to the people who use them in food preparation. PMID:21731445

  5. Two three-dimensional cadmium supramolecular architectures containing extensive hydrogen-bonding networks based on CdSO4 and bis-imidazole ligands

    NASA Astrophysics Data System (ADS)

    Wei, Yang-Fan; Wang, Tao; Pi, Min; Song, Wen; Jin, Chuan-Ming

    2012-11-01

    In this study, two novel three-dimensional (3D) supramolecular networks, [Cd(BIM)2(SO4)(H2O)]·(C2H5OH) (H2O)2 (1) and [Cd(2-mBIM)(SO4)(H2O)3]·H2O (2) [BIM = bis(imidazol-1-yl)-methane, 2-mBIM = bis(2-methylimidazol-1-yl)methane], were synthesized by the reactions of CdSO4 with BIM or 2-mBIM ligand via solvent diffusion methods. The networks were then characterized by elemental analyses, IR, TGA, and X-ray diffraction. Both compounds 1 and 2 have a 3D hydrogen-bonding network with an infinite one-dimensional (1D) double chain structure and an infinite 1D helix channel, respectively. These results suggest that the subtle change in the ligand structure may have a strong influence on the resulting architectures of the metal-organic frameworks. The solid-state luminescent spectra of compounds 1 and 2 indicate weak fluorescent emissions at ca. 338 and 389 nm, respectively.

  6. Effect of metallothionein core promoter region polymorphism on cadmium, zinc and copper levels in autopsy kidney tissues from a Turkish population

    SciTech Connect

    Kayaalti, Zeliha; Mergen, Goerkem; Soeylemezoglu, Tuelin

    2010-06-01

    Metallothioneins (MTs) are metal-binding, low molecular weight proteins and are involved in pathophysiological processes like metabolism of essential metals, metal ion homeostasis and detoxification of heavy metals. Metallothionein expression is induced by various heavy metals especially cadmium, mercury and zinc; MTs suppress toxicity of heavy metals by binding themselves to these metals. The aim of this study was to investigate the association between the - 5 A/G metallothionein 2A (MT2A) single nucleotide polymorphism (SNP) and Cd, Zn and Cu levels in the renal cortex from autopsy cases. MT2A core promoter region - 5 A/G SNP was analyzed by PCR-RFLP method using 114 autopsy kidney tissues and the genotype frequencies of this polymorphism were found as 87.7% homozygote typical (AA), 11.4% heterozygote (AG) and 0.9% homozygote atypical (GG). In order to assess the Cd, Zn and Cu levels in the same autopsy kidney tissues, a dual atomic absorption spectrophotometer system was used and the average levels of Cd, Zn and Cu were measured as 95.54 {+-} 65.58 {mu}g/g, 181.20 {+-} 87.72 {mu}g/g and 17.14 {+-} 16.28 {mu}g/g, respectively. As a result, no statistical association was found between the - 5 A/G SNP in the MT2A gene and the Zn and Cu levels in the renal cortex (p > 0.05), but considerably high accumulation of Cd was monitored for individuals having AG (151.24 {+-} 60.21 {mu}g/g) and GG genotypes (153.09 {mu}g/g) compared with individuals having AA genotype (87.72 {+-} 62.98 {mu}g/g) (p < 0.05). These results show that the core promoter region polymorphism of metallothionein 2A increases the accumulation of Cd in human renal cortex.

  7. Using Expression Profiling to Understand the Effects of Chronic Cadmium Exposure on MCF-7 Breast Cancer Cells

    PubMed Central

    Lubovac-Pilav, Zelmina; Borràs, Daniel M.; Ponce, Esmeralda; Louie, Maggie C.

    2013-01-01

    Cadmium is a metalloestrogen known to activate the estrogen receptor and promote breast cancer cell growth. Previous studies have implicated cadmium in the development of more malignant tumors; however the molecular mechanisms behind this cadmium-induced malignancy remain elusive. Using clonal cell lines derived from exposing breast cancer cells to cadmium for over 6 months (MCF-7-Cd4, -Cd6, -Cd7, -Cd8 and -Cd12), this study aims to identify gene expression signatures associated with chronic cadmium exposure. Our results demonstrate that prolonged cadmium exposure does not merely result in the deregulation of genes but actually leads to a distinctive expression profile. The genes deregulated in cadmium-exposed cells are involved in multiple biological processes (i.e. cell growth, apoptosis, etc.) and molecular functions (i.e. cadmium/metal ion binding, transcription factor activity, etc.). Hierarchical clustering demonstrates that the five clonal cadmium cell lines share a common gene expression signature of breast cancer associated genes, clearly differentiating control cells from cadmium exposed cells. The results presented in this study offer insights into the cellular and molecular impacts of cadmium on breast cancer and emphasize the importance of studying chronic cadmium exposure as one possible mechanism of promoting breast cancer progression. PMID:24376830

  8. CADMIUM SOLUBILITY IN PADDY SOILS: EFFECTS OF SOIL OXIDATION, METAL SULFIDES AND COMPETITIVE IONS.

    EPA Science Inventory

    Cadmium (Cd) is a non-essential element for human nutrition and is an agricultural soil contaminant. Cadmium solubility in paddy soils affects Cd accumulation in the grain of rice. This is a human health risk, exacerbated by the fact that rice grains are deficient in iron (Fe) an...

  9. Effect of Cadmium on Cellular Ultrastructure in Mouse Ovary.

    PubMed

    Wang, Ying; Wang, Xuejuan; Wang, Yanwu; Fan, Rong; Qiu, Chao; Zhong, Shan; Wei, Lei; Luo, Daji

    2015-01-01

    This study aimed at analyzing the cytotoxicity and pathological effects of cadmium on the ovary. Our studies revealed that cadmium was deposited in the mouse ovary after 8 d cadmium injection in vivo. Also, the increase in the rate of body weight was slowed, while the gonadosomatic index was reduced in the CdCl2 group, compared with the control group. Meanwhile, cadmium affected the maturation of follicles, the degradation of corpus luteum, the arrangement of follicles and corpus luteum, and increased the number of atresia follicles. Besides, under the electron microscope, chromatin margination, karopyknosis, swelling of mature cisternae of Golgi apparatus, mitochondrial cristae disappearance, and swelling of the rough endoplasmic reticulum can be observed in the CdCl2 group mice. Collectively, our findings elucidated the morphological mechanism that the exposure of cadmium changed the ultrastructure of cells in ovary tissues.

  10. Direct detection of Pb in urine and Cd, Pb, Cu, and Ag in natural waters using electrochemical sensors immobilized with DMSA functionalized magnetic nanoparticles.

    PubMed

    Yantasee, Wassana; Hongsirikarn, Kitiya; Warner, Cynthia L; Choi, Daiwon; Sangvanich, Thanapon; Toloczko, Mychailo B; Warner, Marvin G; Fryxell, Glen E; Addleman, R Shane; Timchalk, Charles

    2008-03-01

    Urine is universally recognized as one of the best non-invasive matrices for biomonitoring exposure to a broad range of xenobiotics, including toxic metals. Detection of metal ions in urine has been problematic due to the protein competition and electrode fouling. For direct, simple, and field-deployable monitoring of urinary Pb, electrochemical sensors employing superparamagnetic iron oxide (Fe3O4) nanoparticles with a surface functionalization of dimercaptosuccinic acid (DMSA) has been developed. The metal detection involves rapid collection of dispersed metal-bound nanoparticles from a sample solution at a magnetic or electromagnetic electrode, followed by the stripping voltammetry of the metal in acidic medium. The sensors were evaluated as a function of solution pH, the binding affinity of Pb to DMSA-Fe3O4, the ratio of nanoparticles per sample volume, preconcentration time, and Pb concentrations. The effect of binding competitions between the DMSA-Fe3O4 and urine constituents for Pb on the sensor responses was studied. After 90 s of preconcentration in samples containing 25 vol.% of rat urine and 0.1 g L(-1) of DMSA-Fe3O4, the sensor could detect background level of Pb (0.5 ppb) and yielded linear responses from 0 to 50 ppb of Pb, excellent reproducibility (%RSD of 5.3 for seven measurements of 30 ppb Pb), and Pb concentrations comparable to those measured by ICP-MS. The sensor could also simultaneously detect background levels (<1 ppb) of Cd, Pb, Cu, and Ag in river and seawater.

  11. Effects of increased pCO2 and temperature on trace element (Ag, Cd and Zn) bioaccumulation in the eggs of the common cuttlefish, Sepia officinalis

    NASA Astrophysics Data System (ADS)

    Lacoue-Labarthe, T.; Martin, S.; Oberhänsli, F.; Teyssié, J.-L.; Markich, S.; Ross, J.; Bustamante, P.

    2009-11-01

    Cephalopods play a key role in many marine trophic networks and constitute alternative fisheries resources, especially given the ongoing decline in finfish stocks. Along the European coast, the eggs of the cuttlefish Sepia officinalis are characterized by an increasing permeability of the eggshell during development, which leads to selective accumulation of essential and non-essential elements in the embryo. Temperature and pH are two critical factors that affect the metabolism of marine organisms in the coastal shallow waters. In this study, we investigated the effects of pH and temperature through a crossed (3×2; pH 8.1 (pCO2, 400 ppm), 7.85 (900 ppm) and 7.6 (1400 ppm) at 16 and 19°C, respectively) laboratory experiment. Seawater pH showed a strong effect on the egg weight and non-significant impact on the weight of hatchlings at the end of development implying an egg swelling process and embryo growth disturbances. The lower the seawater pH, the more 110 mAg was accumulated in the tissues of hatchlings. The 109Cd concentration factor (CF) decreased with decreasing pH and 65Zn CF reached maximal values pH 7.85, independently of temperature. Our results suggest that pH and temperature affected both the permeability properties of the eggshell and embryonic metabolism. To the best of our knowledge, this is one of the first studies on the consequences of ocean acidification and ocean warming on metal uptake in marine organisms, and our results indicate the need to further evaluate the likely ecotoxicological impact of the global change on the early-life stages of the cuttlefish.

  12. Cadmium-binding proteins from blue crabs (Callinectes sapidus) environmentally exposed to cadmium

    SciTech Connect

    Wiedow, M.A.; Kneip, T.J.; Garte, S.J.

    1982-06-01

    Two heat-stable (90/sup 0/C) cadmium-binding proteins were isolated from the hepatopancreas of Hudson River blue crabs (Callinectes sapidus) by Sephadex G-75 gel filtration chromatography. These proteins have molecular weights of 10,600 and 9,400, and ultraviolet absorbance ratios at 250/280 nm of 12.4 and 5.4, respectively. Repeated freezing and thawing and prolonged (3-6 weeks) storage resulted in protein degradation or loss of Cd-binding activity. These proteins were induced by laboratory injection of CdCl/sub 2/ in blue crabs from pristine (Chesapeake Bay) areas; however, injection of CdCl/sub 2/ into Hudson River animals yielded anomalous chromatography profiles. Cadmium-binding proteins were also identified in blue crab thoracic muscle and gill. The possibility is discussed that these proteins are a type of metallothionein and could contribute to the human toxicity of this cadmium-contaminated edible crustacean.

  13. Biosorption of cadmium with brown macroalgae.

    PubMed

    Gutiérrez, Claudia; Hansen, Henrik K; Hernández, Piroska; Pinilla, Carolina

    2015-11-01

    Sorption experiments for cadmium removal using two brown macroalgae Lessonia nigrescens and Durvillaea antarctica were carried out. Although both types of algae were capable of retaining cadmium, differences in their performance were observed. The optimum pH was 3.7±0.2, and to achieve the equilibrium, 5 days of contact time were necessary for both biosorbents. The maximum experimental uptake obtained was similar for the two biosorbents: 95.3 mg Cd g(-1) by D. antarctica and 109.5 mg Cd g(-1) by L. nigrescens. The Langmuir model described the equilibrium sorption isotherms very well for both biosorbents and the Lagergren pseudo primer order model described the sorption kinetics for L. nigrescens satisfactorily and the Ho and Mckay pseudo second order model for D. antarctica. It was found that cadmium uptake by D. antarctica was faster than by L. nigrescens.

  14. Influence of cadmium speciation for the evaluation of in vitro cadmium toxicity on LLC-PK(1) cells.

    PubMed

    Barrouillet, M P; Ohayon-Courtès, C; Dubus, I; L'Azou, B; Nguyen Ba, C

    2001-01-01

    The main objective of the present work was to assess the potentiality of in vitro models to improve our understanding of cadmium-induced toxicity, especially on epithelial renal cells. Indeed cadmium, a potent toxic metal, poses a serious environmental threat and the mechanisms of its renal toxicity need to be clarified. Cytotoxicity studies presented here were performed in a tubular proximal original established porcine kidney cell line (LLC-PK(1)). We have compared cytotoxicity induced by different chemical cadmium forms in LLC-PK(1) cells as a function of media cell culture pH and protein content. Cadmium stock solutions were prepared either by dissolving cadmium chloride or cadmium sulphate with increasing protein concentrations in the media cell culture. Its pH was monitored during experiments. Cytotoxicity was measured by neutral red uptake after 24 h of exposure. Dose-dependent cytotoxicity curves, calculated with REGTOX, were systematically correlated with pH and protein content. Experiments in vitro revealed that cadmium was dose-dependently toxic for LLC-PK(1) for concentrations ranging from 10(-4) to 10(-6) M. We have noticed a lack of influence of the media cell culture pH on the cadmium cytotoxicity. REGTOX determines closely the EC(50) values but EC(50)CdCl(2)>EC(50)CdSO(4) and cadmium have been assayed with an inductively coupled atomic emission spectrometer (ICP/AES) directly in the media cell culture and the cellular pellet.

  15. On-line preconcentration and determination of lead and cadmium by sequential injection/anodic stripping voltammetry.

    PubMed

    Ninwong, Benjawan; Chuanuwatanakul, Suchada; Chailapakul, Orawon; Dungchai, Wijitar; Motomizu, Shoji

    2012-07-15

    The highly sensitive determination of lead (Pb(II)) and cadmium (Cd(II)) ions, with a limit of detection of 0.01μgL(-1) for Pb(II) and Cd(II), by on-line preconcentration and anodic stripping voltammetry (ASV) controlled by a sequential injection analysis (SIA) system is reported here. The SIA system consisted of a syringe pump, an 8-port selection valve and a 6-port switching valve and was incorporated with a bismuth coated screen-printed carbon nanotube electrode (Bi-SPCNTE). The preconcentration of metal ions was performed by solid phase extraction using an Analig TE-05 chelating resin mini-column on a switching valve. The metal ions collected were then eluted from the resin with 1M hydrochloric acid (HCl), deposited on the electrode surface at -1.3V vs. Ag/AgCl and then measured with ASV. The pH of the sample, eluent volume, flow rate, concentration of the bismuth plating solution and the square-wave voltammetric parameters were optimized. Under the optimum conditions, an enrichment factor of 11.9-fold and 6.6-fold for Pb(II) and Cd(II) ions, respectively, was attained. Detection of Pb(II) and Cd(II) had two different linear ranges (0.5-15μgL(-1) and 15-70μgL(-1)).

  16. Cadmium resistance in an oligochaete and its effect on cadmium trophic transfer to an omnivorous shrimp

    USGS Publications Warehouse

    Wallace, W.G.; Lopez, G.R.; Levinton, J.S.

    1998-01-01

    It has been demonstrated that the deposit-feeding oligochaete Limnodrilus hoffmeisteri inhabiting Foundry Cove (FC), a severely cadmium (Cd)-contaminated cove located on the Hudson River, New York, USA, has evolved resistance to Cd. In this study we investigate how this resistance influences Cd trophic transfer from this oligochaete to the grass shrimp Palaemonetes pugio. Cadmium-resistant worms collected from FC and nonresistant worms collected from an adjacent unpolluted site were investigated for differences in Cd tolerance, accumulation, subcellular distribution and bioavailability to shrimp. FC worms were more tolerant of Cd, surviving twice as long as worms from the unpolluted site during a toxicity bioassay. The 7 d concentration factor of Cd-resistant worms was 4 times greater than that of nonresistant worms (2020 vs 577). There were also differences between worm populations with respect to subcellular Cd distributions. Cd-resistant worms produced metallothionein-like proteins (MT) as well as metal-rich granules (MRG) for Cd storage and detoxification; nonresistant worms only produced MT. These differences in subcellular Cd distributions led to large differences in Cd bioavailability to shrimp; shrimp fed Cd-resistant worms absorbed 21% of the ingested Cd, while those fed nonresistant worms absorbed roughly 4 times that amount (~75%). These absorption efficiencies were in good agreement with the proportions of Cd bound to the worm's most biologically available subcellular fractions (i.e. the cytosol and organelles). Although Cd-resistant worms predominantly stored the toxic metal in biologically unavailable MRG, their increased accumulation of Cd would still result in substantial trophic transfer to shrimp because of the storage of Cd in the biologically available fractions. This work demonstrates that the evolution of Cd resistance can have profound implications for Cd bioavailability and cycling within aquatic ecosystems.

  17. 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

    SciTech Connect

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

  18. 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

    SciTech Connect

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

    2009-06-15

    Three new d{sup 10} coordination polymers, namely [Cd(taa)Cl]{sub n}1, [Hg(taa)Cl]{sub n}2, and [Ag{sub 1.5}(taa)(NO{sub 3}){sub 0.5}]{sub 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{sup 2}){sub 2}(4{sup 2}.5{sup 8}.6{sup 14}.7{sup 3}.8). Compound 2 manifests a doubly interpenetrated decorated alpha-polonium cubic network with the Schlaefli symbol of (4{sup 10}.6{sup 2}.8{sup 3}). Compound 3 consists of 2D puckered layers made up of Ag centers and taa{sup -} 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.

  19. Highly luminescent water-soluble quaternary Zn-Ag-In-S quantum dots for tumor cell-targeted imaging.

    PubMed

    Deng, Dawei; Cao, Jie; Qu, Lingzhi; Achilefu, Samuel; Gu, Yueqing

    2013-04-14

    Exploring the synthesis and biomedical applications of biocompatible quantum dots (QDs) is currently one of the fastest growing fields of nanotechnology. Hence, in this work, we present a facile approach to produce water-soluble (cadmium-free) quaternary Zn-Ag-In-S (ZAIS) QDs. Their efficient photoluminescence (PL) emissions can be tuned widely in the range of 525-625 nm by controlling the size and composition of the QDs with the PL quantum yields (QYs) of 15-30%. These highly luminescent ZAIS QDs are less toxic due to the absence of highly toxic cadmium, and can be versatilely modified by a DHLA-PEG-based ligand. Importantly, after being modified by tumor cell-specific targeting ligands (e.g., folate and RGD peptide), the PEGylated quaternary QDs show potential applications in tumor cell imaging as a promising alternative for Cd-based QDs.

  20. RISK ASSESSMENT FOR CADMIUM IN PHOSPHATE FERTILIZERS

    EPA Science Inventory

    Cadmium induced renal tubular dysfunction occurred where subsistence rice farmers produced their lifetime dietary rice on Zn-mine waste contaminated soils in Japan and other Asian countries. Research has shown that polished rice Cd is greatly increased while grain Zn is not incre...

  1. 29 CFR 1910.1027 - Cadmium.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... pH specified, as described in appendix F to this section; and (3) Cadmium in blood (CdB... a job is available into which the removed employee may be transferred. (C) Whenever an employee is medically removed under paragraph (l)(11) of this section, the employer shall transfer the removed...

  2. 29 CFR 1910.1027 - Cadmium.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... pH specified, as described in appendix F to this section; and (3) Cadmium in blood (CdB... a job is available into which the removed employee may be transferred. (C) Whenever an employee is medically removed under paragraph (l)(11) of this section, the employer shall transfer the removed...

  3. 29 CFR 1910.1027 - Cadmium.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... pH specified, as described in appendix F to this section; and (3) Cadmium in blood (CdB... a job is available into which the removed employee may be transferred. (C) Whenever an employee is medically removed under paragraph (l)(11) of this section, the employer shall transfer the removed...

  4. 29 CFR 1910.1027 - Cadmium.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... pH specified, as described in appendix F to this section; and (3) Cadmium in blood (CdB... a job is available into which the removed employee may be transferred. (C) Whenever an employee is medically removed under paragraph (l)(11) of this section, the employer shall transfer the removed...

  5. 29 CFR 1910.1027 - Cadmium.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... pH specified, as described in appendix F to this section; and (3) Cadmium in blood (CdB... a job is available into which the removed employee may be transferred. (C) Whenever an employee is medically removed under paragraph (l)(11) of this section, the employer shall transfer the removed...

  6. Correlations between cadmium concentration in urine and exposure variables

    NASA Astrophysics Data System (ADS)

    Schwarz, Elmar; Chutsch, Martina; Krause, Christian M.; Schulz, Christine; Thefeld, Wolfgang

    1993-03-01

    As part of the study 'UMWELT und GESUNDHEIT 1985/86', a representative samples of the population of the Federal Republic of Germany was examined for urinary Cd. A log-linear prediction model based on 2109 cases led to an explained variance portion of R2 equals .32. Strong associations were revealed between urinary cadmium and the smoking history and age of the subjects. This is evidence of the function urinary cadmium has as an indicator of the Cd body burden. However, there are also clear connections with physiological parameters (urinary creatinine and serum urea), which are taken to be a modification of Cd excretion by renal function. The association between urinary Cd and serum urea can also be interpreted as a cadmium-induced renal dysfunction. Urinary Cd concentrations tend to be lower in regions with low industrial nitrogen oxide emissions and high economic dynamics, as well as in non- urban residential structures.

  7. Cadmium-induced testicular injury

    SciTech Connect

    Siu, Erica R.; Mruk, Dolores D.; Porto, Catarina S.; Cheng, C. Yan

    2009-08-01

    Cadmium (Cd) is an environmental toxicant and an endocrine disruptor in humans and rodents. Several organs (e.g., kidney, liver) are affected by Cd and recent studies have illustrated that the testis is exceedingly sensitive to Cd toxicity. More important, Cd and other toxicants, such as heavy metals (e.g., lead, mercury) and estrogenic-based compounds (e.g., bisphenols) may account for the recent declining fertility in men among developed countries by reducing sperm count and testis function. In this review, we critically discuss recent data in the field that have demonstrated the Cd-induced toxicity to the testis is probably the result of interactions of a complex network of causes. This is likely to involve the disruption of the blood-testis barrier (BTB) via specific signal transduction pathways and signaling molecules, such as p38 mitogen-activated protein kinase (MAPK). We also summarize current studies on factors that confer and/or regulate the testis sensitivity to Cd, such as Cd transporters and metallothioneins, the impact of Cd on the testis as an endocrine disruptor and oxidative stress inducer, and how it may disrupt the Zn{sup 2+} and/or Ca{sup 2+} mediated cellular events. While much work is needed before a unified mechanistic pathway of Cd-induced testicular toxicity emerges, recent studies have helped to identify some of the likely mechanisms and/or events that take place during Cd-induced testis injury. Furthermore, some of the recent studies have shed lights on potential therapeutic or preventive approaches that can be developed in future studies by blocking or minimizing the destructive effects of Cd to testicular function in men.

  8. Cadmium-induced Testicular Injury*

    PubMed Central

    Siu, Erica R.; Mruk, Dolores D.; Porto, Catarina S.; Cheng, C. Yan

    2009-01-01

    Cadmium (Cd) is an environmental toxicant and an endocrine disruptor in humans. Several organs (e.g., kidney, liver) are affected by Cd and recent studies have illustrated that the testis is exceedingly sensitive to Cd toxicity. More important, Cd and other toxicants, such as heavy metals (e.g., lead, mercury) and estrogenic-based compounds (e.g., bisphenols) may account for the recent declining fertility in men among developed countries by reducing sperm count and testis function. In this review, we critically discuss recent data in the field that have demonstrated the Cd-induced toxicity to the testis is probably the result of interactions of a complex network of causes. This is likely to involve the disruption of the blood-testis barrier (BTB) via specific signal transduction pathways and signaling molecules, such as p38 mitogen-activated protein kinase (MAPK). We also summarize current studies on factors that confer the testis sensitivity to Cd, such as Cd transporters and metallothioneins, and the impact of Cd on the testis as an endocrine disruptor, oxidative stress inducer and how it may disrupt the Zn+2 and/or Ca+2 mediated cellular events. While much work is needed before a unified mechanistic pathway of Cd-induced testicular toxicity is emerged, recent studies have helped to identify some of the likely mechanisms and/or events that take place during Cd-induced testis injury. Furthermore, some of the recent studies have shed lights on potential therapeutic or preventive approaches that can be developed in future studies by blocking or minimizing the destructive effects of Cd to testicular function in men. PMID:19236889

  9. Cadmium Subtraction Method for the Active Albedo Neutron Interrogation of Uranium

    SciTech Connect

    Worrall, Louise G.; Croft, Stephen

    2015-02-01

    This report describes work performed under the Next Generation Safeguards Initiative (NGSI) Cadmium Subtraction Project. The project objective was to explore the difference between the traditional cadmium (Cd) ratio signature and a proposed alternative Cd subtraction (or Cd difference) approach. The thinking behind the project was that a Cd subtraction method would provide a more direct measure of multiplication than the existing Cd ratio method. At the same time, it would be relatively insensitive to changes in neutron detection efficiency when properly calibrated. This is the first published experimental comparison and evaluation of the Cd ratio and Cd subtraction methods.

  10. Protective effects of selenium on cadmium toxicity in rats: Role of altered toxicokinetics and metallothionein

    SciTech Connect

    Wahba, Z.Z.; Coogan, T.P.; Rhodes, S.W.; Waalkes, M.P. )

    1993-02-01

    Selenium prevents the toxicity of the carcinogenic metal cadmium through undefined mechanisms. In this study, the authors determined the effects of selenium on cadmium toxicokinetics and on the ability of cadmium to induce metallothionein, a metal-binding protein that is thought to confer tolerance to cadmium toxicity. To assess the acute protective effects of selenium, male Wistar (WF/NCr) rats were given selenium (as SeO[sub 2]; 10 [mu]mol/kg, sc) at [minus]24, 0, and +24 h relative to cadmium (as CdCl[sub 2]; 45 [mu]mol/kg, sc). Over a 14-d period this dose of cadmium killed 6 out of 10 rats, while 100% of the cadmium-treated rats given concurrent selenium treatments survived. The acute increases in testicular weight that were seen with cadmium, indicative of edematous damage, were also prevented by concurrent selenium treatments. Further studies assessed the distribution and excretion of cadmium and its ability to induce metallothionein in rats given 40 [mu]mol Cd/kg, sc, at time 0 and selenium (10 [mu]mol/kg, sc) at [minus]24 and 0 h. Selenium treatments enhanced cadmium accumulation at 24 h in the liver (23%), testes (145%), and epididymis (35%) but reduced renal accumulation by more than half. Urine samples, collected at 0-3, 3-6, and 6-24 h following cadmium administration, indicted a markedly reduced excretion of cadmium in selenium treated rats during all time periods. The synthesis of metallothionein was stimulated to a much lesser extent by cadmium in selenium-treated rat kidney (41% decrease) but was unaffected in liver. The levels of cadmium-binding proteins within the testes were markedly reduced by cadmium treatment, an effect unmodified by selenium treatments. These results suggest selenium prevents acute cadmium toxicity through a mechanism that does not involve induction of metallothionein and in spite of a markedly enhanced retention of cadmium. 50 refs., 1 fig., 4 tabs.

  11. Interaction of chelating agents with cadmium in mice and rats.

    PubMed Central

    Eybl, V; Sýkora, J; Koutenský, J; Caisová, D; Schwartz, A; Mertl, F

    1984-01-01

    The influence of several chelating agents (CaDTPA, ZnDTPA, CaEDTA, ZnEDTA, DMSA, D-penicillamine and DMPS, DMP and DDC) on the acute toxicity of CdCl2 and on the whole body retention and tissue distribution of cadmium after the IV application of 115mCdCl2 was compared in mice. The chelating agents were applied immediately after the application of cadmium. CaDTPA, ZnDTPA and DMSA appeared to be the most effective antidotes. However, DMSA increased the amount of cadmium retained in kidneys. The treatment of cadmium-poisoned mice with the combination of DMSA (IP) and ZnDTPA (SC) (all the compounds were injected in equimolar dose) decreased the toxicity of cadmium more than treatment with one chelating agents (given in a 2:1 dose). However, by studying the effect of these chelating agents and their combination of the retention and distribution of Cd in mice, it was demonstrated that the combined application of the antidotes showed little or no improvement over the results obtained with the most effective of the individual components. In the urine of rats injected with CdCl2 and treated with the chelating agents (CaDTPA, ZnDTPA, DMSA), the presence of cadmium complexes was demonstrated. The formation of mixed ligand chelates in vivo was not proved. Experiments in mice given a single injection of 115mCd-labeled Cd complexes of DMPS, DMSA and DTPA showed a high retention of cadmium in the organisms after the IV application of CdDMPS and CdDMSA complexes. PMID:6734561

  12. Cadmium and the kidney.

    PubMed Central

    Friberg, L

    1984-01-01

    The paper is a review of certain aspects of importance of cadmium and the kidney regarding the assessment of risks and understanding of mechanisms of action. The review discusses the following topics: history and etiology of cadmium-induced kidney dysfunction and related disorders; cadmium metabolism, metallothionein and kidney dysfunction; cadmium in urine as indicator of body burden, exposure and kidney dysfunction; cadmium levels in kidney and liver as indicators of kidney dysfunction; characteristics of early kidney dysfunction; the critical concentration concept; critical concentrations of cadmium in kidney cortex; and prognosis. PMID:6734547

  13. Cadmium as a respiratory toxicant

    SciTech Connect

    Grose, E.C.; Graham, J.A.

    1987-01-01

    Cadmium is a major respiratory toxicant as evidenced by numerous human and animal studies. Controlled animal inhalation studies provide supporting evidence to the associations observed in epidemiological studies that Cd has the potential to cause lung fibrosis, emphysema, cancer, and kidney disease after prolonged exposure. Shorter-term exposure studies indicate that mechanisms thought to be involved in several of these chronic disease states (especially fibrosis and emphysema) are acutely activated. The evidence of toxicity is sufficiently clear that a TLV has been set and the International Agency for Research on Cancer has named Cd as a Group B1 substance (probable human carcinogen). The risk to Cd exposure is enhanced by its chemical and physical properties that result in bioaccumulation. Thus, even a low-level exposure over long periods of time would be expected to reach doses that could be toxic.

  14. Structure of doubly-even cadmium nuclei studied by βdecay

    NASA Astrophysics Data System (ADS)

    Rinta-Antila, S.; Wang, Y.; Dendooven, P.; Huikari, J.; Jokinen, A.; Kankainen, A.; Kolhinen, V. S.; Lhersonneau, G.; Nieminen, A.; Nummela, S.; Penttilä, H.; Peräjärvi, K.; Szerypo, J.; Wang, J. C.; Äystö, J.

    2005-09-01

    We have studied the structure of even-even cadmium isotopes via beta decay of ground and excited isomeric states of parent silver isotopes. Measurements of mass A = 116, 118 and 120 cadmium nuclides were carried out at an ion guide isotope separation on-line facility at the University of Jyväskylä. Decay schemes of 116mAg, 118mAg, 120gAg and 120mAg are considerably extended. Obtained data have enabled extension of available systematics of the three-phonon states to more neutron-rich cadmium nuclei. As a continuation we have conducted an experiment at ISOLDE, CERN to study heavier A = 122, 124, and 126 cadmium nuclides, the analysis of the collected data is underway.

  15. Local Stoichiometry and Atomic Interdiffusion during Reactive Metal/Mercury-Cadmium-Telluride Junction Formation.

    DTIC Science & Technology

    1987-10-23

    CHART NATIONAL BUREAU OF STANDARDS- 1963-A IfP LOCAL STOICHIOMETRY AND ATOMIC INTERDIFFUSION DURING REACTIVE METAL/ MERCURY- CADMIUM -TELLURIDE...TITLE rand Subtitle) S. TYPE OF REPORT PERIOED LOCAL STOICHIOMETRY AND ATOMIC INTERDIFFUSION Interim, 1/8 DURING REACTIVE METAL/MERCURY- CADMIUM ...identliy by block nuembw) Ag, Ge and Sm overlayers on Mercury- Cadmium -Telluride surfaces exhibit widely different interface reactivity and yield a

  16. Simultaneous removal of cadmium and nitrate in aqueous media by nanoscale zerovalent iron (nZVI) and Au doped nZVI particles.

    PubMed

    Su, Yiming; Adeleye, Adeyemi S; Huang, Yuxiong; Sun, Xiaoya; Dai, Chaomeng; Zhou, Xuefei; Zhang, Yalei; Keller, Arturo A

    2014-10-15

    Nanoscale zerovalent iron (nZVI) has demonstrated high efficacy for treating nitrate or cadmium (Cd) contamination, but its efficiency for simultaneous removal of nitrate and Cd has not been investigated. This study evaluated the reactivity of nZVI to the co-contaminants and by-product formation, employed different catalysts to reduce nitrite yield from nitrate, and examined the transformation of nZVI after reaction. Nitrate reduction resulted in high solution pH, negatively charged surface of nZVI, formation of Fe3O4 (a stable transformation of nZVI), and no release of ionic iron. Increased pH and negative charge contributed to significant increase in Cd(II) removal capacity (from 40 mg/g to 188 mg/g) with nitrate present. In addition, nitrate reduction by nZVI could be catalyzed by Cd(II): while 30% of nitrate was reduced by nZVI within 2 h in the absence of Cd(II), complete nitrate reduction was observed in the presence of 40 mg-Cd/L due to the formation of Cd islands (Cd(0) and CdO) on the nZVI particles. While nitrate was reduced mostly to ammonium when Cd(II) was not present or at Cd(II) concentrations ≥ 40 mg/L, up to 20% of the initial nitrate was reduced to nitrite at Cd(II) concentrations < 40 mg/L. Among nZVI particles doped with 1 wt. % Cu, Ag, or Au, nZVI deposited with 1 wt. % Au reduced nitrite yield to less than 3% of the initial nitrate, while maintaining a high Cd(II) removal capacity.

  17. In vivo analysis of cadmium in battery workers versus measurements of blood, urine, and workplace air.

    PubMed Central

    Börjesson, J; Bellander, T; Järup, L; Elinder, C G; Mattsson, S

    1997-01-01

    OBJECTIVES: To measure in vivo the cadmium concentrations in kidney cortex (kidney-Cd) and in superficial liver tissue (liver-Cd) of nickel cadmium battery workers, and to compare the results with other commonly used estimates of cadmium exposure (current concentrations of cadmium in blood (B-Cd) and urine (U-Cd)) or repeated measurements of cadmium in workplace air (CumAir-Cd). METHODS: The study comprised 30 workers with a range of duration of exposure of 11-51 years. 13 subjects were currently employed, whereas the other 17 had a median period without occupational exposure of eight years before the measurements. The in vivo measurements were made with an x ray fluorescence technique permitting average detection limits of 30 and 3 micrograms cadmium per g tissue in kidney and liver, respectively. RESULTS: 19 of 30 (63%) people had kidney-Cd and 13 of 27 (48%) had liver-Cd above the detection limits. Kidney-Cd ranged from non-detectable to 350 micrograms/g and liver-Cd from non-detectable to 80 micrograms/g. The median kidney-Cd and liver-Cd were 55 micrograms/g and 3 micrograms/g, respectively. Kidney-Cd correlated significantly with B-Cd (r, 0.49) and U-Cd (r, 0.70), whereas liver-Cd correlated significantly with U-Cd (r, 0.58). Neither kidney-Cd nor liver-Cd correlated with the CumAir-Cd. The prevalence of beta 2-microglobulinurea increased with increased liver-Cd. CONCLUSIONS: Current U-Cd can be used to predict the kidney-Cd and liver-Cd measured in vivo. In vivo measurements of kidney-Cd and liver-Cd were not shown to correlate with the individual cadmium exposure estimates, obtained by integration of the cadmium concentration in workplace air. There may be several reasons for this, including uncertainties in the estimate of the individual cumulative exposures as well as in the in vivo measurements. There was a suggestion of a relation between liver-Cd and tubular proteinuria. PMID:9245949

  18. Distribution and age-related bioaccumulation of lead (Pb), mercury (Hg), cadmium (Cd), and arsenic (As) in tissues of common carp (Cyprinus carpio) and European catfish (Sylurus glanis) from the Buško Blato reservoir (Bosnia and Herzegovina).

    PubMed

    Has-Schön, Elizabeta; Bogut, Ivan; Vuković, Rosemary; Galović, Dalida; Bogut, Ante; Horvatić, Janja

    2015-09-01

    The purpose of this study was to quantify the bioaccumulation of Pb, Hg, Cd, and As in tissues of carp (Cyprinus carpio) and catfish (Silurus glanis) from Buško Blato in Bosnia and Herzegovina. Arsenic concentrations were below the Maximal Admissible Concentration (MAC) for Croatia and other countries. Mercury concentrations were below 1 mg kg(-1), but in most muscle samples of both species and all catfish liver samples, the values were higher than 0.5 mg kg(-1) (higher than the MAC for many countries including Croatia). Lead concentrations were higher than 1 mg kg(-1) (the MAC for Croatia) in most muscle samples; all kidney and most catfish liver samples also exceeded 1 mg kg(-1). Cadmium concentrations in all tissues, other than the gonads, were higher than 0.1 mg kg(-1) (MAC for Croatia), with the highest concentrations found in the kidneys. The only gender difference was found in carp, where a 68.4% higher concentration of As was found in the fry compared to the milt (P<0.05). Concentrations of all of the elements were higher in catfish compared to carp for most tissues. Significant correlations were found between all of the elements in the muscles and the liver of carp. In catfish, the muscles were the only tissue in which multiple correlations were found. Linear positive correlations with age and body mass were demonstrated for the concentrations of all heavy metals for all tissues except the gonads in both fish species. We concluded that significant heavy metal accumulation in carp and a catfish tissues correlates with age and body mass; bioaccumulation is species- and tissue-specific and is different for each element.

  19. Cadmium and zinc relationships.

    PubMed

    Elinder, C G; Piscator, M

    1978-08-01

    Cadmium and zinc concentrations in kidney and liver have been measured under different exposure situations in different species including man. The results show that zinc increases almost equimolarly with cadmium in kidney after long-term low-level exposure to cadmium, e.g., in man, horse, pig, and lamb. In contrast, the increase of zinc follows that of cadmium to only a limited extent, e.g., in guinea pig, rabbit, rat, mouse, and chicks. In liver, the cadmium--zinc relationship seems to be reversed in such a way that zinc increases with cadmium more markedly in laboratory animals than in higher mammals. These differences between cadmium and zinc relationships in humans and large farm animals and those in commonly used laboratory animals must be considered carefully before experimental data on cadmium and zinc relationships in laboratory animals can be extrapolated to humans.

  20. A polymorphism in metallothionein 1A (MT1A) is associated with cadmium-related excretion of urinary beta 2‐microglobulin

    SciTech Connect

    Lei, Lijian; Chang, Xiuli; Rentschler, Gerda; Tian, Liting; Zhu, Guoying; Chen, Xiao; Jin, Taiyi; Broberg, Karin

    2012-12-15

    Objectives: Cadmium (Cd) toxicity of the kidney varies between individuals despite similar exposure levels. In humans Cd is mainly bound to metallothioneins (MT), which scavenge its toxic effects. Here we analyzed whether polymorphisms in MT genes MT1A and MT2A influence Cd-related kidney damage. Methods: In a cross-sectional study N = 512 volunteers were selected from three areas in South-Eastern China, which to varying degree were Cd-polluted from a smelter (control area [median Cd in urine U-Cd = 2.67 μg/L], moderately [U-Cd = 4.23 μg/L] and highly [U-Cd = 9.13 μg/L] polluted areas). U-Cd and blood Cd (B-Cd) concentrations were measured by graphite-furnace atomic absorption spectrometry. MT1A rs11076161 (G/A), MT2A rs10636 (G/C) and MT2A rs28366003 (A/G) were determined by Taqman assays; urinary N-Acetyl-beta-(D)-Glucosaminidase (UNAG) by spectrometry, and urinary β2-microglobulin (UB2M) by ELISA. Results: Higher B-Cd (natural log-transformed) with increasing number of MT1A rs11076161 A-alleles was found in the highly polluted group (p-value trend = 0.033; all p-values adjusted for age, sex, and smoking). In a linear model a significant interaction between rs11076161 genotype and B-Cd was found for UNAG (p = 0.001) and UB2M concentrations (p = 0.001). Carriers of the rs11076161 AA genotype showed steeper slopes for the associations between Cd in blood and natural log-transformed UB2M (β = 1.2, 95% CI 0.72–1.6) compared to GG carriers (β = 0.30, 95% CI 0.15–0.45). Also for UNAG (natural log-transformed) carriers of the AA genotype had steeper slopes (β = 0.55, 95% CI 0.27–0.84) compared to GG carriers (β = 0.018, 95% CI − 0.79–0.11). Conclusions: MT1A rs11076161 was associated with B-Cd concentrations and Cd-induced kidney toxicity at high exposure levels. -- Highlights: ► Cadmium is toxic to the kidney but the susceptibility differs between individuals. ► The toxic effect of cadmium is scavenged by metallothioneins. ► A common variant of

  1. HgCdTe Fabrication Using Directed Energy Techniques

    DTIC Science & Technology

    1982-04-01

    HgCdTE Pulsed electron beam processing Mercury Cadmium Teluride Hot wall epitaxy CdTe Heteroepitaxyj Cadmium Teluride Thin Films 20. ABSTRACT...control. Existing CdTe films show extensive twinning and poor surface morphology. Improvements are expected with a shift to sapphire substrates and the...Sample size is currently 0.5 inch square. These films were not twinned and had better surface morphology than the joriginal CdTe substrates. Good

  2. Interaction of chelating agents with cadmium in mice and rats

    SciTech Connect

    Eybl, V.; Sykora, J.; Koutensky, J.; Caisova, D.; Schwartz, A.; Mertl, F.

    1984-03-01

    The influence of several chelating agents (CaDTPA, ZnDTPA, CaEDTA, ZnEDTA, DMSA, D-penicillamine and DMPS, DMP and DDC) on the acute toxicity of CdCl/sub 2/ and on the whole body retention and tissue distribution of cadmium after the IV application of /sup 115mCdCl/sub 2/ was compared in mice. The chelating agents were applied immediately after the application of cadmium. CaDTPA, ZnDTPA and DMSA appeared to be the most effective antidotes. However, DMSA increased the amount of cadmium retained in kidneys. The treatement of cadmium-poisoned mice with the combination of DMSA (IP) and ZnDTPA (SC) (all the compounds were injected in equimolar dose) decreased the toxicity of cadmium more than treatment with one chelating agents (given in a 2:1 dose). However, by studying the effect of these chelating agents and their combination application of the antidotes showed little or no improvement over the results obtained with the most effective of the individual components. In the urine of rats injected with CdCl/sub 2/ and treated with the chelating agents (CaDTPA, ZnDTPA, DMSA), the presence of cadmium complexes was demonstrated. The formation of mixed ligand chelates in vivo was not proved. Experiments in mice given a single injection of /sup 115m/Cd-labeled Cd complexes of DMPS, DMSA and DTPA showed a high retention of cadmium in the organisms after the IV application of CdDMPS and CdDMSA complexes.

  3. Gene-environment interactions between ERCC2, ERCC3, XRCC1 and cadmium exposure in nasal polyposis disease.

    PubMed

    Khlifi, Rim; Olmedo, Pablo; Gil, Fernando; Hammami, Boutheina; Hamza-Chaffai, Amel; Rebai, Ahmed

    2016-11-12

    Gene-environment interactions have long been known to play an important role in complex disease aetiology, such as nasal polyposis (NP). The present study supports the concept that DNA repair gene polymorphisms play critical roles in modifying individual susceptibility to environmental diseases. In fact, we investigated the role of polymorphisms in DNA repair genes and cadmium as risk factors for Tunisian patients with NP. To the best of our knowledge, this is the first report on the impact of combined effects of cadmium and ERCC3 7122 A>G (rs4150407), ERCC2 Lys751Gln (rs13181) and XRCC1 Arg399Gln (rs25487) genes in the susceptibility to NP disease. Significant associations between the risk of developing NP disease and ERCC2 [odds ratio (OR) = 2.0, 95 % confidence interval (CI) = 1.1-3.7, p = 0.023] and ERCC3 (OR = 2.2, 95 % CI = 1.2-4.1, p = 0.013) genotypes polymorphisms were observed. Blood concentrations of Cd in NP patients (2.2 μg/L) were significantly higher than those of controls (0.5 μg/L). A significant interaction between ERCC3 (7122 A>G) polymorphism and blood-Cd levels (for the median of blood-Cd levels: OR = 3.8, 95 % CI = 1.3-10.8, p = 0.014 and for the 75th percentiles of blood-Cd levels: OR = 2.7, 95 % CI = 1.1-7.2, p = 0.041) was found in association with the risk of NP disease. In addition, when we stratified ERCC2, ERCC3 and XRCC1 polymorphism genotypes by the median and 75th percentiles of blood-Cd levels, we found also significant interactions between ERCC2 (Lys751Gln) and ERCC3 (7122 A>G) genotypes polymorphism and this metal in association with NP disease. However, no interaction was found between XRCC1 (Arg399Gln) polymorphism genotypes and Cd in association with NP disease.

  4. Cadmium sulfide membranes

    DOEpatents

    Spanhel, Lubomir; Anderson, Marc A.

    1991-10-22

    A method is described for the creation of novel q-effect cadmium sulfide membranes. The membranes are made by first creating a dilute cadmium sulfide colloid in aqueous suspension and then removing the water and excess salts therefrom. The cadmium sulfide membrane thus produced is luminescent at room temperature and may have application in laser fabrication.

  5. Cadmium sulfide membranes

    DOEpatents

    Spanhel, Lubomir; Anderson, Marc A.

    1992-07-07

    A method is described for the creation of novel q-effect cadmium sulfide membranes. The membranes are made by first creating a dilute cadmium sulfide colloid in aqueous suspension and then removing the water and excess salts therefrom. The cadmium sulfide membrane thus produced is luminescent at room temperature and may have application in laser fabrication.

  6. A two-dimensional CdII coordination polymer: poly[di­aqua­[μ3-5,6-bis­(pyridin-2-yl)pyrazine-2,3-di­carboxyl­ato-κ5 O 2:O 3:O 3,N 4,N 5]cadmium

    PubMed Central

    Alfonso, Monserrat; Stoeckli-Evans, Helen

    2016-01-01

    The reaction of 5,6-bis­(pyridin-2-yl)pyrazine-2,3-di­carb­oxy­lic acid with cadmium dichloride leads to the formation of the title two-dimensional coordination polymer, [Cd(C16H8N4O4)(H2O)2]n. The metal atom is sevenfold coordinated by one pyrazine and one pyridine N atom, two water O atoms, and by two carboxyl­ate O atoms, one of which bridges two CdII atoms to form a Cd2O2 unit situated about a centre of inversion. Hence, the ligand coordinates to the cadmium atom in an N,N′,O-tridentate and an O-monodentate manner. Within the polymer network, there are a number of O—H⋯O hydrogen bonds present, involving the water mol­ecules and the carboxyl­ate O atoms. There are also C—H⋯N and C—H⋯O hydrogen bonds present. In the crystal, the polymer networks lie parallel to the bc plane. They are aligned back-to-back along the a axis with the non-coordinating pyridine rings directed into the space between the networks. PMID:27920921

  7. A method for partitioning cadmium bioaccumulated in small aquatic organisms

    SciTech Connect

    Siriwardena, S.N.; Rana, K.J.; Baird, D.J.

    1995-09-01

    A series of laboratory experiments was conducted to evaluate bioaccumulation and surface adsorption of aqueous cadmium (Cd) by sac-fry of the African tilapia Oreochromis niloticus. In the first experiment, the design consisted of two cadmium treatments: 15 {micro}g Cd{center_dot}L{sup {minus}1} in dilution water and a Cd-ethylenediaminetetraacetic acid (Cd-EDTA) complex at 15 {micro}m{center_dot}L{sup {minus}1}, and a water-only control. There were five replicates per treatment and 40 fish per replicate. It was found that EDTA significantly reduced the bioaccumulation of cadmium by tilapia sac-fry by 34%. Based on the results, a second experiment was conducted to evaluate four procedures: a no-rinse control; rinsing in EDTA; rinsing in distilled water; and rinsing in 5% nitric acid, for removing surface-bound Cd from exposed sac-fry. In this experiment, 30 fish in each of five replicates were exposed to 15 {micro}g Cd{center_dot}L{sup {minus}1} for 72 h, processed through the rinse procedures, and analyzed for total Cd. The EDTA rinse treatment significantly reduced (p<0.05) Cd concentrations of the exposed fish relative to those receiving no rinse. It was concluded that the EDTA rinse technique may be useful in studies evaluating the partitioning of surface-bound and accumulated cadmium in small aquatic organisms.

  8. Factors influencing cadmium mobilization by diethyldithiocarbamate: chelator dose, cadmium burden, and sex. [Mice

    SciTech Connect

    Gale, G.R.; Atkins, L.M.; Walker, E.M. Jr.; Smith, A.B.

    1983-03-01

    A study was made of the effects of diethyldithiocarbamate (DDTC) on organ distribution and excretion of cadmium (Cd) as influenced by DDTC dose, Cd burden, and sex of mice. One hundred to 250 mg per kg of DDTC did not promote mobilization of hepatic Cd, but it was effective at 500 mg per kg. All doses tested were significantly effective in mobilizing renal and splenic Cd, and the response was dose-dependent, as was the increase in brain levels of Cd. Cadmium mobilization by DDTC following Cd loads over a three-fold range appeared to be first order in nature; i.e., a given regimen of DDTC treatment promoted mobilization of a virtually constant percentage of the Cd administered, rather than a constant amount of Cd. The response to DDTC was markedly sex-dependent, being more effective in females than males. In organs of control Cd-loaded mice one sex-related difference was noted; spleens of females retained a considerably greater percentage of administered Cd than those of males.

  9. Silicate reduces cadmium uptake into cells of wheat.

    PubMed

    Greger, Maria; Kabir, Ahmad H; Landberg, Tommy; Maity, Pooja J; Lindberg, Sylvia

    2016-04-01

    Cadmium (Cd) is a health threat all over the world and high Cd content in wheat causes high Cd intake. Silicon (Si) decreases cadmium content in wheat grains and shoot. This work investigates whether and how silicate (Si) influences cadmium (Cd) uptake at the cellular level in wheat. Wheat seedlings were grown in the presence or absence of Si with or without Cd. Cadmium, Si, and iron (Fe) accumulation in roots and shoots was analysed. Leaf protoplasts from plants grown without Cd were investigated for Cd uptake in the presence or absence of Si using the fluorescent dye, Leadmium Green AM. Roots and shoots of plants subjected to all four treatments were investigated regarding the expression of genes involved in the Cd uptake across the plasma membrane (i.e. LCT1) and efflux of Cd into apoplasm or vacuole from the cytosol (i.e. HMA2). In addition, phytochelatin (PC) content and PC gene (PCS1) expression were analysed. Expression of iron and metal transporter genes (IRT1 and NRAMP1) were also analysed. Results indicated that Si reduced Cd accumulation in plants, especially in shoot. Si reduced Cd transport into the cytoplasm when Si was added both directly during the uptake measurements and to the growth medium. Silicate downregulated LCT1 and HMA2 and upregulated PCS1. In addition, Si enhanced PC formation when Cd was present. The IRT1 gene, which was downregulated by Cd was upregulated by Si in root and shoot facilitating Fe transport in wheat. NRAMP1 was similarly expressed, though the effect was limited to roots. This work is the first to show how Si influences Cd uptake on the cellular level.

  10. Cadmium accumulation and growth response to cadmium stress of eighteen plant species.

    PubMed

    Shi, Gangrong; Xia, Shenglan; Liu, Caifeng; Zhang, Zheng

    2016-11-01

    This study investigated the cadmium (Cd) accumulation and growth response to Cd stress of 18 plant species. After growth for 30 days in the sand containing 0, 2, or 10 mg Cd kg(-1), seedlings were evaluated for growth parameters, specific root length, and Cd accumulation. The 18 species differ greatly in Cd accumulation and resistance to Cd stress, depending on Cd concentrations in the sand. Under high Cd condition (10 mg kg(-1)), the 18 species were classified into two groups: (1) Indian mustard and rapeseed having high Cd tolerance and increased accumulation capacity in shoots could be considered as Cd accumulators, and (2) the remaining 16 non-accumulators constitute a species continuum from the indicators to excluders. Shoot Cd concentration showed exponential decay relationships with biomass production, absolute growth rate, and growth ratio, indicating that biomass production negatively relates to the shoot Cd concentration in non-accumulators via dilution or concentration effect. Species with high biomass generally accumulate low Cd in the shoots and display high Cd-tolerant capacity. Indian mustard and rapeseed are promising species for long-term phytoextraction of Cd-contaminated farmlands for bioenergy production.

  11. [Speciation analysis of cadmium in cadmium-enriched plants with SE-HPLC combined with ICP-MS and ESI-MS].

    PubMed

    Li, Bin; Liu, Li; Wang, Qiu-Quan; Yan, Hua; Huang, Ben-Li

    2010-04-01

    Different species of ferns (pyrrosia lingua, Lepisorus thunbergianus, Lycopodium japonicum, Elaphoglossum yoshinagae and Woodwardia japonica) were cultivated using different species of cadmium as cultivation solution. The results showed that there were differences in enrichment amounts of cadmium in different parts of plants (amounts in root > in stem > in leaves). And it was found that different species of cadmium could induce synthesization of plant--chelated peptides (PCs) with different extents. And then PCs was coordinated with cadmium to decrease the toxicity from cadmium. There are some kinds of peptides ligands found in plants, which are mainly PC3, iso-PC3(betaAla) and iso-PC2(betaAla). In the present paper, the distribution of cadmium in different parts of ferns was studied after the ferns were intimidated with different species of cadmium. And the species of PCs-Cd coordination compounds were also investigated to explain the detoxification mechanism aroused by it.

  12. Synthesis and characterization of nano Cdo/NiO, nano Ag/ZnO composites & Ag/Zno embedded polymer nanocomposites

    NASA Astrophysics Data System (ADS)

    Godasu, Rahul

    Nanoparticles are finest structures whose size composition is within nanometer range. Thus nanoparticles are a collection of atoms bonded together with structural radius less than 100 nm. Nanocomposites are multiphase solid materials where one of the phases has one, two or three dimensions of less than 100 mn. Nano composites are prepared to improve mechanical, electrical, thermal, optical, electrochemical, catalytic properties from its parent materials. For instance, blend of nanoparticles with a polymer are called polymer nanocomposites. Nanostructured composites like Cadmium oxide/Nickel oxide (CdO/NiO) and silver/zinc oxide (Ag/ZnO) were prepared. Characterization of these prepared nanocomposites were carried out using X-ray powder diffraction, Differential scanning calorimetry, Scanning electron microscopy and the average sizes were determined using zeta sizer. Results obtained using characterization methods were in agreement stating that we were successful in synthesizing composites. The prepared Ag/ZnO nano composite was embedded in PCL polymer and we made films of PCL embedded with nano composite. The SEM image of the 5% Ag/ZnO embedded film clearly shows two regions, which indicates that Ag/ZnO nano composite was successfully embedded into the polymer using a non insitu method. SEM results also showed that the Zinc Oxide nano particles were successfully embedded into the polymer .

  13. The effects of low environmental cadmium exposure on bone density

    SciTech Connect

    Trzcinka-Ochocka, M.; Jakubowski, M.; Szymczak, W.; Janasik, B.; Brodzka, R.

    2010-04-15

    Recent epidemiological data indicate that low environmental exposure to cadmium, as shown by cadmium body burden (Cd-U), is associated with renal dysfunction as well as an increased risk of cadmium-induced bone disorders. The present study was designed to assess the effects of low environmental cadmium exposure, at the level sufficient to induce kidney damage, on bone metabolism and mineral density (BMD). The project was conducted in the area contaminated with cadmium, nearby a zinc smelter located in the region of Poland where heavy industry prevails. The study population comprised 170 women (mean age=39.7; 18-70 years) and 100 men (mean age=31.9; 18-76 years). Urinary and blood cadmium and the markers of renal tubular dysfunction ({beta}{sub 2}M-U RBP, NAG), glomerular dysfunction (Alb-U and {beta}{sub 2}M-S) and bone metabolism markers (BAP-S, CTX-S) as well as forearm BMD, were measured. The results of this study based on simple dose-effect analysis showed the relationship between increasing cadmium concentrations and an increased excretion of renal dysfunction markers and decreasing bone density. However, the results of the multivariate analysis did not indicate the association between exposure to cadmium and decrease in bone density. They showed that the most important factors that have impact on bone density are body weight and age in the female subjects and body weight and calcium excretion in males. Our investigation revealed that the excretion of low molecular weight proteins occurred at a lower level of cadmium exposure than the possible loss of bone mass. It seems that renal tubular markers are the most sensitive and significant indicators of early health effects of cadmium intoxication in the general population. The correlation of urinary cadmium concentration with markers of kidney dysfunction was observed in the absence of significant correlations with bone effects. Our findings did not indicate any effects of environmental cadmium exposure on bone

  14. Cadmium and renal cancer

    SciTech Connect

    Il'yasova, Dora; Schwartz, Gary G. . E-mail: gschwart@wfubmc.edu

    2005-09-01

    Background: Rates of renal cancer have increased steadily during the past two decades, and these increases are not explicable solely by advances in imaging modalities. Cadmium, a widespread environmental pollutant, is a carcinogen that accumulates in the kidney cortex and is a cause of end-stage renal disease. Several observations suggest that cadmium may be a cause of renal cancer. Methods: We performed a systematic review of the literature on cadmium and renal cancer using MEDLINE for the years 1966-2003. We reviewed seven epidemiological and eleven clinical studies. Results: Despite different methodologies, three large epidemiologic studies indicate that occupational exposure to cadmium is associated with increased risk renal cancer, with odds ratios varying from 1.2 to 5.0. Six of seven studies that compared the cadmium content of kidneys from patients with kidney cancer to that of patients without kidney cancer found lower concentrations of cadmium in renal cancer tissues. Conclusions: Exposure to cadmium appears to be associated with renal cancer, although this conclusion is tempered by the inability of studies to assess cumulative cadmium exposure from all sources including smoking and diet. The paradoxical findings of lower cadmium content in kidney tissues from patients with renal cancer may be caused by dilution of cadmium in rapidly dividing cells. This and other methodological problems limit the interpretation of studies of cadmium in clinical samples. Whether cadmium is a cause of renal cancer may be answered more definitively by future studies that employ biomarkers of cadmium exposure, such as cadmium levels in blood and urine.

  15. Distribution and concentration of cadmium in human kidney

    SciTech Connect

    Svartengren, M.; Elinder, C.G.; Friberg, L.; Lind, B.

    1986-01-01

    The left kidneys from twenty males, aged 30 to 59, were examined. On an average, the cortex, medulla, and the remainder (renal pelvis and adjacent fatty tissue) constituted 65, 27, and 8 percent of the whole kidney weight, respectively. The mean cadmium concentrations were 18.4, 6.9,, and 3.2 ..mu..g Cd/g wet wt, respectively. The mean whole kidney cadmium concentration was 14.4 ..mu..g Cd/g wet wt. The kidney cortex concentration of cadmium can be approximated by multiplying the whole kidney concentration by a factor of 1.25, which is somewhat lower than the factor of 1.5 previously used. It may be necessary to recalculate previously reported estimates of critical concentrations for cadmium in kidney cortex based on neutron activation analyses in vivo of whole kidney.

  16. Salt affects plant Cd-stress responses by modulating growth and Cd accumulation.

    PubMed

    Xu, Jin; Yin, Hengxia; Liu, Xiaojing; Li, Xia

    2010-01-01

    Cadmium contamination is a serious environmental problem for modern agriculture and human health. Salinity affects plant growth and development, and interactions between salt and cadmium have been reported. However, the molecular mechanisms of salinity-cadmium interactions are not fully understood. Here, we show that a low concentration of salt alleviates Cd-induced growth inhibition and increases Cd accumulation in Arabidopsis thaliana. Supplementation with low concentrations of salt reduced the reactive oxygen species level in Cd-stressed roots by increasing the contents of proline and glutathione and down-regulating the expression of RCD1, thereby protecting the plasma membrane integrity of roots under cadmium stress. Salt supplementation substantially reduces the Cd-induced elevation of IAA oxidase activity, thereby maintaining auxin levels in Cd-stressed plants, as indicated by DR5::GUS expression. Salt supply increased Cd absorption in roots and increased Cd accumulation in leaves, implying that salt enhances both Cd uptake in roots and the root-to-shoot translocation of Cd. The elevated Cd accumulation in plants in response to salt was found to be correlated with the elevated levels of phytochelatin the expression of heavy metal transporters AtHMA1-4, especially AtHMA4. Salt alleviated growth inhibition caused by Cd and increased Cd accumulation also was observed in Cd accumulator Solanum nigrum.

  17. Dietary Intake Estimates and Urinary Cadmium Levels in Danish Postmenopausal Women

    PubMed Central

    Vacchi-Suzzi, Caterina; Eriksen, Kirsten T.; Levine, Keith; McElroy, Jane; Tjønneland, Anne; Raaschou-Nielsen, Ole; Harrington, James M.; Meliker, Jaymie R.

    2015-01-01

    Background Cadmium is a known carcinogen that can disrupt endocrine signalling. Cigarette smoking and food are the most common routes of non-occupational exposure to cadmium. Cadmium accumulates in the kidney and can be measured in urine, making urine cadmium (U-Cd) a biomarker of long-term exposure. However dietary-cadmium (D-Cd) intake estimates are often used as surrogate indicator of cadmium exposure in non-smoking subjects. It is therefore important to investigate the concordance between D-Cd estimates obtained with Food Frequency Questionnaires and U-Cd. Methods U-Cd levels were compared with estimated dietary-cadmium (D-Cd) intake in 1764 post-menopausal women from the Danish Diet, Cancer and Health cohort. For each participant, a food frequency questionnaire, and measures of cadmium content in standard recipes were used to judge the daily intake of cadmium, normalized by daily caloric intake. Cadmium was measured by ICP-MS in spot urine sampled at baseline and normalized by urinary creatinine. Information on diet, socio-demographics and smoking were self-reported at baseline. Results Linear regressions between U-Cd and D-Cd alone revealed minimal but significant positive correlation in never smokers (R2 = 0.0076, β = 1.5% increase per 1 ng Cd kcal-1, p = 0.0085, n = 782), and negative correlation in current smokers (R2 = 0.0184, β = 7.1% decrease per 1 ng Cd kcal-1 change, p = 0.0006, n = 584). In the full study population, most of the variability in U-Cd was explained by smoking status (R2 = 0.2450, n = 1764). A forward selection model revealed that the strongest predictors of U-Cd were age in never smokers (Δ R2 = 0.04), smoking duration in former smokers (Δ R2 = 0.06) and pack-years in current smokers (Δ R2 = 0.07). Food items that contributed to U-Cd were leafy vegetables and soy-based products, but explained very little of the variance in U-Cd. Conclusions Dietary-Cd intake estimated from food frequency questionnaires correlates only minimally

  18. Fractionation of Stable Cadmium Isotopes in the Cadmium Tolerant Ricinus communis and Hyperaccumulator Solanum nigrum

    NASA Astrophysics Data System (ADS)

    Wei, Rongfei; Guo, Qingjun; Wen, Hanjie; Liu, Congqiang; Yang, Junxing; Peters, Marc; Hu, Jian; Zhu, Guangxu; Zhang, Hanzhi; Tian, Liyan; Han, Xiaokun; Ma, Jie; Zhu, Chuanwei; Wan, Yingxin

    2016-04-01

    Cadmium (Cd) isotopes provide new insights into Cd uptake, transport and storage mechanisms in plants. Therefore, the present study adopted the Cd-tolerant Ricinus communis and Cd-hyperaccumulator Solanum nigrum, which were cultured under controlled conditions in a nutrient solution with variable Cd supply, to test the isotopic fractionation of Cd during plant uptake. The Cd isotope compositions of nutrient solutions and organs of the plants were measured by multiple collector inductively coupled plasma mass spectrometry (MC-ICPMS). The mass balance of Cd isotope yields isotope fractionations between plant and Cd source (δ114/110Cdorgans-solution) of ‑0.70‰ to ‑0.22‰ in Ricinus communis and ‑0.51‰ to ‑0.33‰ in Solanum nigrum. Moreover, Cd isotope fractionation during Cd transport from stem to leaf differs between the Cd-tolerant and -hyperaccumulator species. Based on these results, the processes (diffusion, adsorption, uptake or complexation), which may induce Cd isotope fractionation in plants, have been discussed. Overall, the present study indicates potential applications of Cd isotopes for investigating plant physiology.

  19. Fractionation of Stable Cadmium Isotopes in the Cadmium Tolerant Ricinus communis and Hyperaccumulator Solanum nigrum.

    PubMed

    Wei, Rongfei; Guo, Qingjun; Wen, Hanjie; Liu, Congqiang; Yang, Junxing; Peters, Marc; Hu, Jian; Zhu, Guangxu; Zhang, Hanzhi; Tian, Liyan; Han, Xiaokun; Ma, Jie; Zhu, Chuanwei; Wan, Yingxin

    2016-04-14

    Cadmium (Cd) isotopes provide new insights into Cd uptake, transport and storage mechanisms in plants. Therefore, the present study adopted the Cd-tolerant Ricinus communis and Cd-hyperaccumulator Solanum nigrum, which were cultured under controlled conditions in a nutrient solution with variable Cd supply, to test the isotopic fractionation of Cd during plant uptake. The Cd isotope compositions of nutrient solutions and organs of the plants were measured by multiple collector inductively coupled plasma mass spectrometry (MC-ICPMS). The mass balance of Cd isotope yields isotope fractionations between plant and Cd source (δ(114/110)Cdorgans-solution) of -0.70‰ to -0.22‰ in Ricinus communis and -0.51‰ to -0.33‰ in Solanum nigrum. Moreover, Cd isotope fractionation during Cd transport from stem to leaf differs between the Cd-tolerant and -hyperaccumulator species. Based on these results, the processes (diffusion, adsorption, uptake or complexation), which may induce Cd isotope fractionation in plants, have been discussed. Overall, the present study indicates potential applications of Cd isotopes for investigating plant physiology.

  20. Fractionation of Stable Cadmium Isotopes in the Cadmium Tolerant Ricinus communis and Hyperaccumulator Solanum nigrum

    PubMed Central

    Wei, Rongfei; Guo, Qingjun; Wen, Hanjie; Liu, Congqiang; Yang, Junxing; Peters, Marc; Hu, Jian; Zhu, Guangxu; Zhang, Hanzhi; Tian, Liyan; Han, Xiaokun; Ma, Jie; Zhu, Chuanwei; Wan, Yingxin

    2016-01-01

    Cadmium (Cd) isotopes provide new insights into Cd uptake, transport and storage mechanisms in plants. Therefore, the present study adopted the Cd-tolerant Ricinus communis and Cd-hyperaccumulator Solanum nigrum, which were cultured under controlled conditions in a nutrient solution with variable Cd supply, to test the isotopic fractionation of Cd during plant uptake. The Cd isotope compositions of nutrient solutions and organs of the plants were measured by multiple collector inductively coupled plasma mass spectrometry (MC-ICPMS). The mass balance of Cd isotope yields isotope fractionations between plant and Cd source (δ114/110Cdorgans-solution) of −0.70‰ to −0.22‰ in Ricinus communis and −0.51‰ to −0.33‰ in Solanum nigrum. Moreover, Cd isotope fractionation during Cd transport from stem to leaf differs between the Cd-tolerant and -hyperaccumulator species. Based on these results, the processes (diffusion, adsorption, uptake or complexation), which may induce Cd isotope fractionation in plants, have been discussed. Overall, the present study indicates potential applications of Cd isotopes for investigating plant physiology. PMID:27076359

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

    SciTech Connect

    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.

  2. Associations between cadmium exposure and circulating levels of sex hormones in postmenopausal women

    SciTech Connect

    Ali, Imran; Engström, Annette; Vahter, Marie; Skerfving, Staffan; Lundh, Thomas; Lidfeldt, Jonas; Samsioe, Göran; Halldin, Krister; Åkesson, Agneta

    2014-10-15

    Recent epidemiological as well as in vivo and in vitro studies collectively suggest that the metalloestrogen cadmium (Cd) could be a potential risk factor for hormone-related cancers in particularly breast cancer. Assessment of the association between Cd exposure and levels of endogenous sex hormones is of pivotal importance, as increased levels of such have been associated with a higher risk of breast cancer in postmenopausal women. The present study investigated the perceived relationship (multivariable-adjusted linear regression analyses) between Cd exposure [blood Cd (B-Cd) and urinary Cd (U-Cd)], and serum levels of androstenedione, testosterone, estradiol, and sex-hormone binding globulin (SHBG), in 438 postmenopausal Swedish women without hormone replacement therapy (HRT). A significant positive association between B-Cd (median 3.4 nmol/L) and serum testosterone levels, as well as a significant inverse association between B-Cd and serum estradiol levels and with the estradiol/testosterone ratio were encountered. However, U-Cd (median 0.69 nmol/mmol creatinine) was inversely associated with serum estradiol levels only. Our data may suggest that Cd interferes with the levels of testosterone and estradiol in postmenopausal women, which might have implications for breast cancer risk. - Highlights: • Low level cadmium exposure may interfere with the levels of steroid hormones. • Cadmium exposure was associated with increased serum testosterone concentrations. • Cadmium exposure was associated with decreased estradiol/testosterone ratio. • Cadmium exposure may have implications for breast-cancer promotion.

  3. Characterization studies on cadmium-mycophosphatin from the mushroom Agaricus macrosporus

    SciTech Connect

    Meisch, H.U.; Schmitt, J.A.

    1986-03-01

    A low molecular weight Cd-binding phosphoglycoprotein, cadmium-mycophosphatin, has been isolated from the mushroom Agaricus macrosporus. This protein has a molecular weight of 12,000 dalton and contains no sulfur but a high amount of acid amino acids (Glu, Asp), and carbohydrates (glucose, galactose). Cadmium-mycophosphatin has an isoelectric point less than pH 2, binds cadmium with a dissociation constant of K/sub D/ = 1.59 x 10 M (pK/sub D/ = 6.8) and is saturated with 13.5 mole Cd/mole, all Cd-binding sites being equivalent. It is suggested that Cd is bound by phosphoserine groups, similar relations being known from calcium-binding proteins in animals. From A. macrosporus four other low-molecular weight glycoproteins have been isolated which contain sulfur and bind cadmium and copper. The biological significance of these Cd-binding proteins is discussed.

  4. A new pathway for vacuolar cadmium sequestration in Saccharomyces cerevisiae: YCF1-catalyzed transport of bis(glutathionato)cadmium

    PubMed Central

    Li, Ze-Sheng; Lu, Yu-Ping; Zhen, Rui-Guang; Szczypka, Mark; Thiele, Dennis J.; Rea, Philip A.

    1997-01-01

    The yeast cadmium factor (YCF1) gene encodes an MgATP-energized glutathione S-conjugate transporter responsible for the vacuolar sequestration of organic compounds after their S-conjugation with glutathione. However, while YCF1 was originally isolated according to its ability to confer resistance to cadmium salts, neither its mode of interaction with Cd2+ nor the relationship between this process and organic glutathione-conjugate transport are known. Here we show through direct comparisons between vacuolar membrane vesicles purified from Saccharomyces cerevisiae strain DTY167, harboring a deletion of the YCF1 gene, and the isogenic wild-type strain DTY165 that YCF1 mediates the MgATP-energized vacuolar accumulation of Cd·glutathione complexes. The substrate requirements, kinetics and Cd2+/glutathione stoichiometry of cadmium uptake and the molecular weight of the transport-active complex demonstrate that YCF1 selectively catalyzes the transport of bis(glutathionato)cadmium (Cd·GS2). On the basis of these results—the Cd2+ hypersensitivity of DTY167, versus DTY165, cells, the inducibility of YCF1-mediated transport, and the rapidity and spontaneity of Cd·GS2 formation—this new pathway is concluded to contribute substantially to Cd2+ detoxification. PMID:8990158

  5. Cadmium induces direct morphological changes in mesangial cell culture.

    PubMed

    L'Azou, Béatrice; Dubus, Isabelle; Ohayon-Courtès, Céline; Labouyrie, Jean; Perez, Laurent; Pouvreau, Carole; Juvet, Ludivine; Cambar, Jean

    2002-10-15

    The cadmium produced by industrial and agricultural practice represents a major environmental pollutant which may induce severe damage, especially in the kidney where cadmium accumulates. While cadmium is known to severely impair renal tubular functions, glomerular structures are also potential targets. The present study investigated the effects of cadmium on glomerular mesangial cell cultures after short- and long-term exposures, requiring for each endpoint specific culture conditions. After 30 min exposure to 1 microM CdCl(2), used as non-lethal concentration, 0.14 ng/microg proteins of cadmium was internalized by the cells as evaluated by atomic emision spectrometry and induced a significant, cell surface reduction (8.9+/-1.9%). These morphological changes could be correlated to smooth muscle alpha-actin disorganization, without quantitative change in its protein expression level as evaluated by Western-blot and Northern-blot analysis (SMAmRNA/28sRNA, 1.78 CdCl(2) vs. 1.42 control). For longer exposure times, in complex medium, cadmium uptake was efficient (0.36 ng/microg proteins) and induced changes in the actin cytoskeleton with no loss of cell membrane integrity. This study suggests that cultured mesangial cells provide an alternative model to study the effect of cadmium, and underlines the importance of using well-defined conditions to study further intracellular mechanisms.

  6. Gadolinium chloride pretreatment ameliorates acute cadmium-induced hepatotoxicity.

    PubMed

    Kyriakou, Loukas G; Tzirogiannis, Konstantinos N; Demonakou, Maria D; Kourentzi, Kalliopi T; Mykoniatis, Michael G; Panoutsopoulos, Georgios I

    2013-08-01

    Cadmium is a known industrial and environmental pollutant. It causes hepatotoxicity upon acute administration. Features of cadmium-induced acute hepatoxicity encompass necrosis, apoptosis, peliosis and inflammatory infiltration. Gadolinium chloride (GdCl3) may prevent cadmium-induced hepatotoxicity by suppressing Kupffer cells. The effect of GdCl3 pretreatment on a model of acute cadmium-induced liver injury was investigated. Male Wistar rats 4-5 months old were injected intraperitoneally with normal saline followed by cadmium chloride (CdCl2; 6.5 mg/kg) or GdCl3 (10 mg/kg) followed by CdCl2 (6.5 mg/kg; groups I and II, respectively). Rats of both the groups were killed at 9, 12, 16, 24, 48 and 60 h after cadmium intoxication. Liver sections were analyzed for necrosis, apoptosis, peliosis and mitoses. Liver regeneration was also evaluated by tritiated thymidine incorporation into hepatic DNA. Serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were also determined. Hepatic necrosis, hepatocyte and nonparenchymal cell apoptosis and macroscopic and microscopic types of peliosis hepatis were minimized by gadolinium pretreatment. Serum levels of AST and ALT were also greatly diminished in rats of group II. Tritiated thymidine incorporation into hepatic DNA was increased in gadolinium pretreatment rats. Kupffer cell activation was minimal in both the groups of rats. Gadolinium pretreatment attenuates acute cadmium-induced liver injury in young Wistar rats, with mechanisms other than Kupffer cell elimination.

  7. Cadmium in rice: Transport mechanisms, influencing factors, and minimizing measures.

    PubMed

    Li, Hui; Luo, Na; Li, Yan Wen; Cai, Quan Ying; Li, Hui Yuan; Mo, Ce Hui; Wong, Ming Hung

    2017-05-01

    Cadmium (Cd) accumulation in rice and its subsequent transfer to food chain is a major environmental issue worldwide. Understanding of Cd transport processes and its management aiming to reduce Cd uptake and accumulation in rice may help to improve rice growth and grain quality. Moreover, a thorough understanding of the factors influencing Cd accumulation will be helpful to derive efficient strategies to minimize Cd in rice. In this article, we reviewed Cd transport mechanisms in rice, the factors affecting Cd uptake (including physicochemical characters of soil and ecophysiological features of rice) and discussed efficient measures to immobilize Cd in soil and reduce Cd uptake by rice (including agronomic practices, bioremediation and molecular biology techniques). These findings will contribute to ensuring food safety, and reducing Cd risk on human beings.

  8. Cadmium exposure from smoking cigarettes: variations with time and country where purchased.

    PubMed

    Elinder, C G; Kjellström, T; Lind, B; Linnman, L; Piscator, M; Sundstedt, K

    1983-10-01

    Cadmium has been determined in 26 brands of cigarettes purchased in eight different countries throughout the world and in 16 different samples of cigarettes produced in Sweden between 1918 and 1968. In addition the amount of cadmium released from smoking one cigarette to the particulate phase collected from a smoking simulation machine, corresponding to the amount actually inhaled by a smoker, has been determined. The cadmium concentration in different brands of cigarettes ranged from 0.19 to 3.0 micrograms Cd/g dry wt, with a general tendency toward lower values in cigarettes from developing countries. No systematic change in the cadmium concentration of cigarettes with time could be revealed. The amount of cadmium inhaled from smoking one cigarette containing about 1.7 microgram Cd was estimated to be 0.14 to 0.19 microgram, corresponding to about 10% of the total cadmium content in the cigarette.

  9. Sodium chloride enhances cadmium tolerance through reducing cadmium accumulation and increasing anti-oxidative enzyme activity in tobacco.

    PubMed

    Zhang, Bing-Lin; Shang, Sheng-Hua; Zhang, Hai-Tao; Jabeen, Zahra; Zhang, Guo-Ping

    2013-06-01

    The effect of sodium chloride (NaCl) on cadmium (Cd) uptake, translocation, and oxidative stress was investigated using 2 tobacco cultivars differing in Cd tolerance. The growth inhibition of the tobacco plants exposed to Cd toxicity was in part alleviated by moderate addition of NaCl in the culture solution. Cadmium concentration of shoots and roots in the 2 cultivars increased with increasing Cd levels in the solution and decreased with the addition of NaCl. The addition of NaCl could alleviate the oxidative stress caused by Cd toxicity, as reflected by reduced production of malondialdehyde and recovered or enhanced activities of antioxidative enzymes catalase and glutathione peroxidase. The results also showed that the enhancement of antioxidative enzyme activity by NaCl for the tobacco plants exposed to Cd stress is related to induced Ca signaling.

  10. The role of vitamin E or clay in growing Japanese quail fed diets polluted by cadmium at various levels.

    PubMed

    Abou-Kassem, D E; Mahrose, Kh M; Alagawany, M

    2016-03-01

    This study was conducted to verify whether vitamin (Vit) E or natural clay as feed additives has the potential to modulate the deleterious effects resulting from exposure to cadmium (Cd) in growing Japanese quail. 648 Japanese quail chicks (1 week old) were used to evaluate the effects of dietary Cd (0, 40, 80 and 120 mg/kg diet) and two levels of Vit E (0, 250 mg/kg diet) or two levels of natural clay (0 and 100 mg/kg diet) to study the influences of Cd, Vit E, clay or their different combinations on growth performance, carcass traits, some blood biochemical components and Cd residues in muscles and liver. Live BW and weight gain of quails were linearly decreased with increasing dietary Cd levels. Moreover, feed conversion was significantly worsened with increasing Cd level. Mortality percentage was linearly increased as dietary Cd level increased up to 120 mg/kg diet. Carcass percentage was linearly decreased as dietary Cd level increased. While, giblets percentage were linearly and quadratically differed as dietary Cd level increased. Cd caused significant changes in total plasma protein, albumin, globulin, A/G ratio, creatinine, urea-N and uric acid concentrations as well as ALT, AST and ALP activities. Increasing dietary Cd level was associated with its increase in the muscles and liver. Dietary supplementation with 250 mg of Vit E/kg diet or 100 mg clay/kg improved live BW, BW gain and feed conversion when compared with the un-supplemented diet. Quails fed diet contained 250 mg Vit E/kg and those fed 100 mg clay/kg had the highest percentages of carcass and dressing than those fed the un-supplemented diet. Blood plasma biochemical components studied were better when birds received 250 mg of Vit E/kg diet and those received 100 mg clay/kg. Cd residues in the muscles and liver were significantly less in the birds had 250 mg of Vit E/kg or those received 100 mg clay/kg diet than those un-supplemented with Vit E. Growth performance traits and blood plasma

  11. Induction of cytoprotective autophagy in PC-12 cells by cadmium

    SciTech Connect

    Wang, Qiwen; Zhu, Jiaqiao; Zhang, Kangbao; Jiang, Chenyang; Wang, Yi; Yuan, Yan; Bian, Jianchun; Liu, Xuezhong; Gu, Jianhong; Liu, Zongping

    2013-08-16

    Highlights: •Cadmium can promote early upregulation of autophagy in PC-12 cells. •Autophagy precedes apoptosis in cadmium-treated PC-12 cells. •Cadmium-induced autophagy is cytoprotective in PC-12 cells. •Class III PI3K/beclin-1/Bcl-2 signaling pathway plays a positive role in cadmium-triggered autophagy. -- Abstract: Laboratory data have demonstrated that cadmium (Cd) may induce neuronal apoptosis. However, little is known about the role of autophagy in neurons. In this study, cell viability decreased in a dose- and time-dependent manner after treatment with Cd in PC-12 cells. As cells were exposed to Cd, the levels of LC3-II proteins became elevated, specific punctate distribution of endogenous LC3-II increased, and numerous autophagosomes appeared, which suggest that Cd induced a high level of autophagy. In the late stages of autophagy, an increase in the apoptosis ratio was observed. Likewise, pre-treatment with chloroquine (an autophagic inhibitor) and rapamycin (an autophagic inducer) resulted in an increased and decreased percentage of apoptosis in contrast to other Cd-treated groups, respectively. The results indicate that autophagy delayed apoptosis in Cd-treated PC-12 cells. Furthermore, co-treatment of cells with chloroquine reduced autophagy and cell activity. However, rapamycin had an opposite effect on autophagy and cell activity. Moreover, class III PI3 K/beclin-1/Bcl-2 signaling pathways served a function in Cd-induced autophagy. The findings suggest that Cd can induce cytoprotective autophagy by activating class III PI3 K/beclin-1/Bcl-2 signaling pathways. In sum, this study strongly suggests that autophagy may serve a positive function in the reduction of Cd-induced cytotoxicity.

  12. Cadmium-substituted skeletal troponin C: cadmium-113 NMR spectroscopy and metal binding investigations

    SciTech Connect

    Ellis, P.D.; Strang, P.; Potter, J.D.

    1984-08-25

    The binding of cadmium to skeletal troponin C (STnC) has been measured in two ways. Equilibrium binding experiments have shown two cadmium binding sites on STnC with a high affinity for Cd/sup 2 +/ and two with a lower affinity for Cd/sup 2 +/. The former binding constant is comparable to Ca/sup 2 +/ binding to the Ca/sup 2 +/-Mg/sup 2 +/ (structural) sites of STnC; the latter is about a factor of one hundred less than Ca/sup 2 +/ binding to the Ca/sup 2 +/-specific (regulatory) sites of STnC. In the presence of Mg/sup 2 +/ the affinity of Cd/sup 2 +/ for the higher affinity sites was lowered. These data clearly suggest that the sites with high affinity for Cd/sup 2 +/ are the same as the Ca/sup 2 +/-Mg/sup 2 +/ sites. The /sup 113/Cd NMR is temperature-dependent. At room temperature two resonances at -107.8 and -112.7 ppm are seen. Lowering the temperature to 4/sup 0/C alters the cadmium exchange dynamics, and results in a four line /sup 113/Cd spectrum. The two new resonances probably arise from cadmium binding to the Ca/sup 2 +/-specific sites on STnC; whereas, the resonances at -107.8 and -112.7 ppm correspond to cadmium binding at the Ca/sup 2 +/-Mg/sup 2 +/-sites, respectively. When the /sup 113/Cd/sup 2 +/-substituted protein was titrated with Ca/sup 2 +/, the two resonances of the high affinity sites were reduced, followed by a reduction of the lower affinity Cd/sup 2 +/ sites. Since the direct binding experiments demonstrate that the high affinity Cd/sup 2 +/ sites are the Ca/sup 2 +/-Mg/sup 2 +/ sites, it is concerned that Cd/sup 2 +/ binding to the protein dramatically alters the affinity of the Ca/sup 2 +/-Mg/sup 2 +/ sites for Ca/sup 2 +/ possibly with allosteric coupling network between binding sites.

  13. Cyproterone acetate induces a cellular tolerance to cadmium in rat liver epithelial cells involving reduced cadmium accumulation.

    PubMed

    Takiguchi, M; Cherrington, N J; Hartley, D P; Klaassen, C D; Waalkes, M P

    2001-08-13

    Several reports indicate that some steroids, in particular sex steroid hormones, can modify cadmium toxicity. We recently reported that cyproterone acetate (CA), a synthetic steroidal antiandrogen that is closely related in structure to progesterone, affects cadmium toxicity in mice. In the present study, we investigated the effect of CA on cadmium toxicity in a rat liver epithelial cell line (TRL 1215) in vitro. Cells were exposed to various concentrations of CA (0,1,10, or 50 microM) for 24 h and subsequently exposed to cadmium (0,50, or 100 microM; as CdCl2) for an additional 24 h. CA pretreatment resulted in a clear decrease in the sensitivity to cadmium. Additional time course study showed CA pretreatment provided protection against cadmium toxicity but only when given for 6 or more hours prior to cadmium exposure. Cellular cadmium accumulation was markedly reduced (60% decrease) in cells pretreated for 6 or more hours with CA. In the presence of protein synthesis inhibitors the protective effect of CA toward cadmium toxicity was abolished. However, in the presence of the GSH synthesis inhibitor, L-buthionine (S,R)-sulfoximide (BSO), the protective effect of CA toward cadmium toxicity remained. CA alone increased metallothionein (MT) levels 2.4-fold, while cadmium (50 microM) alone resulted in a 8.9-fold increase over control. However, cadmium-induced MT synthesis was markedly decreased by CA pretreatment probably because of reduced cadmium accumulation. Analysis of various metal transporters by bDNA signal amplification assay revealed that the ZnT-1 transporter gene, which encodes for a membrane protein associated with zinc efflux, was expressed three-fold more in CA treated cells than control. These data show that CA pretreatment provides protection against cadmium toxicity in vitro and indicate that this protection is due to a decreased accumulation of cadmium rather than through activation of MT synthesis. This decrease of cellular cadmium accumulation

  14. Bond thermal expansion and effective pair potential in crystals: the case of cadmium selenide.

    PubMed

    Sanson, Andrea

    2011-08-10

    The local dynamics of cadmium selenide (CdSe) with wurtzite structure has been investigated by molecular dynamics simulations, using a many-body Tersoff potential. The radial distribution functions (i.e., the effective pair potentials) of the first seven coordination shells have been determined as a function of temperature, as well as their parallel and perpendicular mean-square relative atomic displacements. The bond thermal expansion of the first coordination shell is mainly due to the asymmetry of the effective pair potential. In contrast, the bond thermal expansion of the outer shells is mostly due to a rigid shift of the effective pair potential. This behavior, recently observed also in simple cubic monoatomic crystals, can be generalized and related to the correlation of atomic motion. Finally, a shift toward lower values of the first Se-Cd effective pair potential has been observed when increasing the temperature, confirming previous findings by extended x-ray absorption fine-structure measurements. Differently from superionic conductors like AgI and CuBr, in which this anomalous negative shift was tentatively explained by cluster distortion and cation diffusion, the negative shift of CdSe is related to the peculiar properties of the crystalline potential.

  15. Future trends in soil cadmium concentration under current cadmium fluxes to European agricultural soils.

    PubMed

    Six, L; Smolders, E

    2014-07-01

    The gradual increase of soil cadmium concentrations in European soils during the 20th century has prompted environmental legislation to limit soil cadmium (Cd) accumulation. Mass balances (input-output) reflecting the period 1980-1995 predicted larger Cd inputs via phosphate (P) fertilizers and atmospheric deposition than outputs via crop uptake and leaching. This study updates the Cd mass balance for the agricultural top soils of EU-27+Norway (EU-27+1). Over the past 15 years, the use of P fertilizers in the EU-27+1 has decreased by 40%. The current mean atmospheric deposition of Cd in EU is 0.35 g Cd ha(-1) yr(-1), this is strikingly smaller than values used in the previous EU mass balances (~3 g Cd ha(-1) yr(-1)). Leaching of Cd was estimated with most recent data of soil solution Cd concentrations in 151 soils, which cover the range of European soil properties. No significant time trends were found in the data of net applications of Cd via manure, compost, sludge and lime, all being small sources of Cd at a large scale. Modelling of the future long-term changes in soil Cd concentrations in agricultural top soils under cereal or potato culture predicts soil Cd concentrations to decrease by 15% over the next 100 years in an average scenario, with decreasing trends in some scenarios being more prevalent than increasing trends in other scenarios. These Cd balances have reverted from the general positive balances estimated 10 or more years ago. Uncertainty analysis suggests that leaching is the most uncertain relative to other fluxes.

  16. Cadmium in tobacco

    SciTech Connect

    Yue, L. )

    1992-03-01

    The present study was conducted to determine the cadmium level in tobacco planted in five main tobacco-producing areas, a cadmium polluted area, and in cigarettes produced domestically (54 brands). The results indicate that average cadmium content in tobacco was 1.48 (0.10-4.95 mg/kg), which was similar to that of Indian tobacco (1.24 mg/kg), but the cadmium of tobacco produced in the cadmium polluted area was quite high (8.60 mg/kg). The average cigarette cadmium was 1.05 micrograms/g (with filter tip) and 1.61 micrograms/g (regular cigarette). Therefore special attention should be paid to the soil used in planting tobacco.

  17. Cadmium - a metallohormone?

    PubMed Central

    Byrne, Celia; Divekar, Shailaja D.; Storchan, Geoffrey B.; Parodi, Daniela A.; Martin, Mary Beth

    2009-01-01

    Cadmium is a heavy metal that is often referred to as the metal of the 20th Century. It is widely used in industry principally in galvanizing and electroplating, in batteries, in electrical conductors, in the manufacture of alloys, pigments, and plastics, and in the stabilization of phosphate fertilizers. As a byproduct of smelters, cadmium is a prevalent environmental contaminant. In the general population, exposure to cadmium occurs primarily through dietary sources, cigarette smoking, and, to a lesser degree, drinking water. Although the metal has no known physiological function, there is evidence to suggest that the cadmium is a potent metallohormone. This review summarizes the increasing evidence that cadmium mimics the function of steroid hormones, addresses our current understanding of the mechanism by which cadmium functions as a hormone, and discusses its potential role in development of the hormone dependent cancers. PMID:19362102

  18. Cadmium - A metallohormone?

    SciTech Connect

    Byrne, Celia; Divekar, Shailaja D.; Storchan, Geoffrey B.; Parodi, Daniela A.; Martin, Mary Beth

    2009-08-01

    Cadmium is a heavy metal that is often referred to as the metal of the 20th century. It is widely used in industry principally in galvanizing and electroplating, in batteries, in electrical conductors, in the manufacture of alloys, pigments, and plastics, and in the stabilization of phosphate fertilizers. As a byproduct of smelters, cadmium is a prevalent environmental contaminant. In the general population, exposure to cadmium occurs primarily through dietary sources, cigarette smoking, and, to a lesser degree, drinking water. Although the metal has no known physiological function, there is evidence to suggest that the cadmium is a potent metallohormone. This review summarizes the increasing evidence that cadmium mimics the function of steroid hormones, addresses our current understanding of the mechanism by which cadmium functions as a hormone, and discusses its potential role in development of the hormone dependent cancers.

  19. Inclusion free cadmium zinc tellurium and cadmium tellurium crystals and associated growth method

    DOEpatents

    Bolotnikov, Aleskey E.; James, Ralph B.

    2010-07-20

    The present disclosure provides systems and methods for crystal growth of cadmium zinc tellurium (CZT) and cadmium tellurium (CdTe) crystals with an inverted growth reactor chamber. The inverted growth reactor chamber enables growth of single, large, high purity CZT and CdTe crystals that can be used, for example, in X-ray and gamma detection, substrates for infrared detectors, or the like. The inverted growth reactor chamber enables reductions in the presence of Te inclusions, which are recognized as an important limiting factor in using CZT or CdTe as radiation detectors. The inverted growth reactor chamber can be utilized with existing crystal growth techniques such as the Bridgman crystal growth mechanism and the like. In an exemplary embodiment, the inverted growth reactor chamber is a U-shaped ampoule.

  20. Impacts of anthropogenic pressures on the water quality of the Gironde Estuary (SW France) from the Urban Agglomeration of Bordeaux: spatial characterization and inputs of trace metal elements (Ag, As, Cd, Cu, Pb and Zn)

    NASA Astrophysics Data System (ADS)

    Kessaci, Kahina; Coynel, Alexandra; Blanc, Gérard; Deycard, Victoria N.; Derriennic, Hervé; Schäfer, Jörg

    2014-05-01

    Recent European legislation (2000/60/CE) has listed eight trace metal elements as priority toxic substances for water quality. Urban metal inputs into hydrosystems are of increasing interest to both scientists and managers facing restrictive environmental protection policies, population increase and changing metal applications. The Gironde Estuary (SW France; 625 km2) is known for its metal/metalloid pollution originating from industrial (e.g. Cd, Zn, Cu, As, Ag, Hg) or agricultural sources (e.g. Cu) in the main fluvial tributaries (Garonne and Dordogne Rivers). However, little peer-reviewed scientific work has addressed the impact of urban sources on the Gironde Estuary, especially the Urban Agglomeration of Bordeaux (~1 million inhabitants) located on the downstream branch of the Garonne River. In this study, a snapshot sampling campaign was performed in 2011 for characterizing the spatial distribution of dissolved and particulate metal/metalloid (As, Ag, Cd, Pb, Zn, Cu) concentrations in three suburban watersheds: the Jalle of Blanquefort (330 km2), Eau Bourde (140 km2), and Peugue (112 km2). Furthermore, particulate metal Enrichment Factors (EF) were calculated using local geochemical background measured at the bottom of a sediment core (492 cm). Results indicated that metal concentrations displayed a high spatial variability depending on the suburban watershed and the studied element. Local concentrations anomalies were observed for: (i) As in the Eau Bourde River in dissolved (4.2 μg/l) and particulate phases (246 mg/kg; EF= 20) and attributed to a nearby industrial incinerator; (ii) Zn in the Peugue River with maximum dissolved and particulate concentrations of 87 μg/l and 1580 mg/kg (EF=17), respectively, probably due to urban habitation runoff; (iii) Ag in the Jalle of Blanquefort River with high dissolved (74 ng/l) and particulate concentrations (33.7 mg/kg; EF=117) due to industrial activities in the downstream part. Based on hydro

  1. Cadmium kinetics in freshwater clams. Uptake of cadmium by the excised gill of Anodonta anatina

    SciTech Connect

    Holwerda, D.A.; de Knecht, J.A.; Hemelraad, J.; Veenhof, P.R.

    1989-03-01

    There are several, and sometimes conflicting, reports on metal interaction during bioaccumulation from a mixture of heavy metals by marine or estuarine organisms. Concerning the influence of zinc on Cd uptake, it was found in a previous study with the freshwater clam Anodonta cygnea that zinc retarded the accumulation of cadmium when present in a hundred-fold excess over the latter metal. In the only in vitro investigation known, it was shown that the uptake of cadmium by the excised gills of the seal mussel Mytilus edulis was not affected by co-exposure with other metal ions or by the presence of metabolic inhibitors. By contrast, bioaccumulation of cadmium in M. edulis was strongly reduced by co-exposure to zinc in a hundred-fold excess over cadmium. The clear effect of zinc on Cd accumulation in A. cygnea prompted the authors to investigate this phenomenon in an in vitro model. The primary aim was to detect whether the in vivo effect of zinc is caused by a direct influence on the gill epithelium or is sustained by a behavioral response of the animal. At the same time, the possible effect of some other exogenous factors on Cd uptake was examined. In addition, it was investigated whether the rate of in vitro uptake is a function of gill size.

  2. Concentration of cadmium in cacao beans and its relationship with soil cadmium in southern Ecuador.

    PubMed

    Chavez, E; He, Z L; Stoffella, P J; Mylavarapu, R S; Li, Y C; Moyano, B; Baligar, V C

    2015-11-15

    Cadmium (Cd) content in cacao beans above a critical level (0.6 mg kg(-1)) has raised concerns in the consumption of cacao-based chocolate. Little is available regarding Cd concentration in soil and cacao in Ecuador. The aim of this study was to determine the status of Cd in both, soils and cacao plants, in southern Ecuador. Soil samples were collected from 19 farms at 0-5, 5-15, 15-30, and 30-50 cm depths, whereas plant samples were taken from four nearby trees. Total recoverable and extractable Cd were measured at the different soil depths. Total recoverable Cd ranged from 0.88 to 2.45 and 0.06 to 2.59, averaged 1.54 and 0.85 mg kg(-1), respectively in the surface and subsurface soils whereas the corresponding values for M3-extractable Cd were 0.08 to 1.27 and 0.02 to 0.33 with mean values of 0.40 and 0.10 mg kg(-1). Surface soil in all sampling sites had total recoverable Cd above the USEPA critical level for agricultural soils (0.43 mg kg(-1)), indicating that Cd pollution occurs. Since both total recoverable and M3-extractable Cd significantly decreased depth wise, anthropogenic activities are more likely the source of contamination. Cadmium in cacao tissues decreased in the order of beans>shell>leaves. Cadmium content in cacao beans ranged from 0.02 to 3.00, averaged 0.94 mg kg(-1), and 12 out of 19 sites had bean Cd content above the critical level. Bean Cd concentration was highly correlated with M3- or HCl-extractable Cd at both the 0-5 and 5-15 cm depths (r=0.80 and 0.82 for M3, and r=0.78 and 0.82 for HCl; P<0.01). These results indicate that accumulation of Cd in surface layers results in excessive Cd in cacao beans and M3- or HCl-extractable Cd are suitable methods for predicting available Cd in the studied soils.

  3. DNA repair systems as targets of cadmium toxicity

    SciTech Connect

    Giaginis, Constantinos; Gatzidou, Elisavet; Theocharis, Stamatios . E-mail: theocharis@ath.forthnet.gr

    2006-06-15

    Cadmium (Cd) is a heavy metal and a potent carcinogen implicated in tumor development through occupational and environmental exposure. Recent evidence suggests that proteins participating in the DNA repair systems, especially in excision and mismatch repair, are sensitive targets of Cd toxicity. Cd by interfering and inhibiting these DNA repair processes might contribute to increased risk for tumor formation in humans. In the present review, the information available on the interference of Cd with DNA repair systems and their inhibition is summarized. These actions could possibly explain the indirect contribution of Cd to mutagenic effects and/or carcinogenicity.

  4. CdS and CdS/CdSe sensitized ZnO nanorod array solar cells prepared by a solution ions exchange process

    SciTech Connect

    Chen, Ling; Gong, Haibo; Zheng, Xiaopeng; Zhu, Min; Zhang, Jun; Yang, Shikuan; Cao, Bingqiang

    2013-10-15

    Graphical abstract: - Highlights: • CdS and CdS/CdSe quantum dots are assembled on ZnO nanorods by ion exchange process. • The CdS/CdSe sensitization of ZnO effectively extends the absorption spectrum. • The performance of ZnO/CdS/CdSe cell is improved by extending absorption spectrum. - Abstract: In this paper, cadmium sulfide (CdS) and cadmium sulfide/cadmium selenide (CdS/CdSe) quantum dots (QDs) are assembled onto ZnO nanorod arrays by a solution ion exchange process for QD-sensitized solar cell application. The morphology, composition and absorption properties of different photoanodes were characterized with scanning electron microscope, transmission electron microscope, energy-dispersive X-ray spectrum and Raman spectrum in detail. It is shown that conformal and uniform CdS and CdS/CdSe shells can grow on ZnO nanorod cores. Quantum dot sensitized solar cells based on ZnO/CdS and ZnO/CdS/CdSe nanocable arrays were assembled with gold counter electrode and polysulfide electrolyte solution. The CdS/CdSe sensitization of ZnO can effectively extend the absorption spectrum up to 650 nm, which has a remarkable impact on the performance of a photovoltaic device by extending the absorption spectrum. Preliminary results show one fourth improvement in solar cell efficiency.

  5. Cadmium block of isometric contractions of isolated bullfrog atrial cells.

    PubMed

    Shepherd, N; Kavaler, F; Spielman, W

    1991-02-01

    We studied the effect of cadmium, verapamil, and quinacrine on the force of contraction (Fp) of isolated, single, field-stimulated bullfrog atrial cells. All agents were applied or removed rapidly (t1/2 approximately 15 ms) to minimize intracellular concentration changes other than intracellular calcium concentration. Two components of twitch force were observed, one blocked by micromolar Cd2+ and the other by millimolar Cd2+. The two contributed about equally to the activation of the twitch. The "cadmium-sensitive" portion of force (that affected by [Cd] less than or equal to 100 microM) had a K1/2 approximately 1 microM, was identical in magnitude to, and not additive with, a "verapamil-sensitive" (10 microM) component of force, was most strongly affected by 50-ms pulses of Cd2+ when they were applied in the mechanical latent period, and was potentiated by catecholamines. The cadmium-insensitive portion of force was abolished by the removal of extracellular calcium and was greatly potentiated by quinacrine (3 or 10 microM), a blocker of Na-Ca exchange. The results are consistent with the idea that activating calcium enters the cell via both an inactivating cadmium-sensitive L-type channel and a noninactivating cadmium-insensitive mechanism that is not Na-Ca exchange and leaves the cell via Na-Ca exchange.

  6. Replacement of Cd on Connectors Alernative and Issues

    DTIC Science & Technology

    2012-07-01

    corrosion 1,11  EN-PTFE Substrate: Aluminium 6061 Parts: Panel Test: According MIL-DTL-81706 (load=200 Psi) Conclusion: • Different behavior...2. Product Overview 3. Cadmium alternatives in Europe 4. Focus on alternatives to Cd on aluminium connector Product requirements Research on...equivalent to aluminium material 8 3. Cadmium alternatives in Europe Cd free european solution overview in 2012 Cd free candidate

  7. Accumulation and effects of cadmium on guppy (Poecilia reticulata) fed cadmium-dosed cladocera (Moina macrocopa)

    SciTech Connect

    Hatakeyama, S.; Yasuno, M.

    1982-08-01

    The study examines the rate of cadmium uptake and body burdens which cause adverse effects on the survival and growth of guppies when they are exposed to Cd dosed in zooplankton (Moina macrocopa) and Cd dissolved in water. Eight guppies fed Moina dosed at 20 ..mu..g Cd/L water died before 10 days. Growth of the remainder of the guppies exposed at this rate was impaired initially but was returned to control level around the 10th day of the study. (JMT)

  8. Determination of arsenic, antimony, bismuth, cadmium, copper, lead, molybdenum, silver and zinc in geological materials by atomic-absorption spectrometry

    USGS Publications Warehouse

    Viets, J.G.; O'Leary, R. M.; Clark, Robert J.

    1984-01-01

    Arsenic, antimony, bismuth, cadmium, copper, lead, molybdenum, silver and zinc are very useful elements in geochemical exploration. In the proposed method, geological samples are fused with potassium pyrosulphate and the fusate is dissolved in a solution of hydrochloric acid, ascorbic acid and potassium iodide. When this solution is shaken with a 10% V/V Aliquat 336 - isobutyl methyl ketone organic phase, the nine elements of interest are selectively partitioned in the organic phase. All nine elements can then be determined in the organic phase using flame atomic-absorption spectrometry. The method is rapid and allows the determination of Ag and Cd at levels down to 0.1 p.p.m., Cu, Mo, and Zn down to 0.5 p.p.m., Pb, Bi and Sb down to 1 p.p.m. and As down to 5 p.p.m. in geological materials.

  9. A one-step synthesis of cadmium selenide quantum dots from a novel single source precursor.

    PubMed

    Crouch, D J; O'Brien, P; Malik, M A; Skabara, P J; Wright, S P

    2003-06-21

    A new approach to the one-step synthesis of cadmium selenide (CdSe) quantum dots is reported using the air stable complex cadmium imino-bis(diisopropylphosphine selenide); the ligand is readily prepared from elemental selenium and the precursor, quantum dots of comparable quality to those prepared by conventional methods are obtained.

  10. In Situ Localized Surface Plasmon Resonance (LSPR) Spectroscopy to Investigate Kinetics of Chemical Bath Deposition of CdS Thin Films

    DOE PAGES

    Kalyanaraman, Ramki; Taz, Humaira; Ruther, Rose E.; ...

    2015-02-11

    Techniques that can characterize the early stages of thin film deposition from liquid phase processes can aid greatly in our understanding of mechanistic aspects of chemical bath deposition (CBD). Here we have used localized surface plasmon resonance (LSPR) spectroscopy to monitor in-situ the kinetics of early-stage growth of cadmium sulfide (CdS) thin films on Ag nanoparticle on quartz substrates. Real-time shift during CdS deposition showed that the LSPR wavelength red shifted rapidly due to random deposition of CdS on the substrate, but saturated at longer times. LSPR modeling showed that these features could be interpreted as an initial deposition ofmore » CdS islands followed by preferential deposition onto itself. The CdS also showed significantly enhanced Raman signals up to 170 times due to surface enhanced raman scattering (SERS) from the CdS/Ag NP regions. The ex-situ SERS effect supported the LSPR shift suggesting that these techniques could be used to understand nucleation and growth phenomena from the liquid phase.« less

  11. In Situ Localized Surface Plasmon Resonance (LSPR) Spectroscopy to Investigate Kinetics of Chemical Bath Deposition of CdS Thin Films

    SciTech Connect

    Kalyanaraman, Ramki; Taz, Humaira; Ruther, Rose E.; Nanda, Jagjit

    2015-02-11

    Techniques that can characterize the early stages of thin film deposition from liquid phase processes can aid greatly in our understanding of mechanistic aspects of chemical bath deposition (CBD). Here we have used localized surface plasmon resonance (LSPR) spectroscopy to monitor in-situ the kinetics of early-stage growth of cadmium sulfide (CdS) thin films on Ag nanoparticle on quartz substrates. Real-time shift during CdS deposition showed that the LSPR wavelength red shifted rapidly due to random deposition of CdS on the substrate, but saturated at longer times. LSPR modeling showed that these features could be interpreted as an initial deposition of CdS islands followed by preferential deposition onto itself. The CdS also showed significantly enhanced Raman signals up to 170 times due to surface enhanced raman scattering (SERS) from the CdS/Ag NP regions. The ex-situ SERS effect supported the LSPR shift suggesting that these techniques could be used to understand nucleation and growth phenomena from the liquid phase.

  12. Cadmium exposure activates the ERK signaling pathway leading to altered osteoblast gene expression and apoptotic death in Saos-2 cells.

    PubMed

    Arbon, Kate S; Christensen, Cody M; Harvey, Wendy A; Heggland, Sara J

    2012-02-01

    Recent reports of cadmium in electronic waste and jewelry have increased public awareness regarding this toxic metal. Human exposure to cadmium is associated with the development of osteoporosis. We previously reported cadmium induces apoptosis in human tumor-derived Saos-2 osteoblasts. In this study, we examine the extracellular signal-regulated protein kinase (ERK) and protein kinase C (PKC) pathways in cadmium-induced apoptosis and altered osteoblast gene expression. Saos-2 osteoblasts were cultured in the presence or absence of 10μM CdCl(2) for 2-72h. We detected significant ERK activation in response to CdCl(2) and pretreatment with the ERK inhibitor PD98059 attenuated cadmium-induced apoptosis. However, PKCα activation was not observed after exposure to CdCl(2) and pretreatment with the PKC inhibitor, Calphostin C, was unable to rescue cells from cadmium-induced apoptosis. Gene expression studies were conducted using qPCR. Cells exposed to CdCl(2) exhibited a significant decrease in the bone-forming genes osteopontin (OPN) and alkaline phosphatase (ALP) mRNA. In contrast, SOST, whose protein product inhibits bone formation, significantly increased in response to CdCl(2). Pretreatment with PD98059 had a recovery effect on cadmium-induced changes in gene expression. This research demonstrates cadmium can directly inhibit osteoblasts via ERK signaling pathway and identifies SOST as a target for cadmium-induced osteotoxicity.

  13. Cadmium-zinc interactions in plants and extractable cadmium and zinc fractions in soil

    SciTech Connect

    Abdel-Sabour, M.F.; Mortvedt, J.J.; Kelsoe, J.J.

    1988-06-01

    This study related Cd-Zn concentrations in plants to levels of Cd and Zn in soil recovered by several extractants soon after application of Cd and Zn sources to soil. Cadmium nitrate and ZnSO/sub 4/ or Zn(C/sub 2/H/sub 3/O/sub 2/)/sub 2/ were mixed with a Zn-deficient Crowley silt loam soil, cropped with corn (Zea mays L.), and then cropped with Swiss chard (Beta vulgaris). Applied Cd significantly increased the Cd/Zn ratio in both crops, especially in Swiss chard, which accumulates heavy metals. A previously published sequential-extraction procedure was used to fractionate Cd and Zn in soil after the corn harvest. Results of statistical analyses showed the highest correlation between Cd uptake by each crop and the carbonate and sulfide fractions of Cd in soil. Including other Cd fractions resulted in only slightly higher R/sup 2/ values. Zinc uptake by each crop was best related to the organic fraction of Zn in soil, and including the other Zn fractions did not affect the relationship. These results show that Cd and Zn uptake by corn or Swiss chard was not related to similar chemical fractions of these elements in soil, and that the Cd/Zn ratio in plant tops was significantly affected by both Cd and Zn applications to soil.

  14. Optimization of chemical bath deposited cadmium sulfide thin films

    SciTech Connect

    Oladeji, I.O.; Chow, L.

    1997-07-01

    Cadmium sulfide (CdS) is known to be an excellent heterojunction partner of p-type cadmium telluride (CdTe) or p-type copper indium diselenide (CuInSe{sub 2}) due essentially to its high electron affinity. It is widely used as a window material in high efficiency thin-film solar cells based on CdTe or CuInSe{sub 2} owing to its transparency and photoconductivity among other properties. The authors report the optimization of CdS thin film grown by chemical bath deposition where homogeneous reactions are minimized. The optimum parameters have enabled them to maximize the thickness of the deposited film in a single dip and to grow thicker films by periodically replenishing the concentration of reactants while the substrate remains continuously dipped in the reaction bath. Characterization results reveal the deposited CdS films exhibit improved optical and electrical properties.

  15. Analyzing the role of soil and rice cadmium pollution on human renal dysfunction by correlation and path analysis.

    PubMed

    Luo, Hui-Fang; Zhang, Jie-Ying; Jia, Wen-Jing; Ji, Feng-Min; Yan, Qiong; Xu, Qing; Ke, Shen; Ke, Jin-Shan

    2017-01-01

    The aim of this study was to investigate the role of soil and rice pollution on human renal dysfunction. The participants were 97 inhabitants (46 men and 51 women) who are aged 50 to 60 years old and have been living in Xiaogan (Hubei, China) from birth. We collected samples of soil, rice, and urinary correspondingly. Urinary N-acetyl-β-D-glucosaminidase (NAG) and β-2-microglobulin (β2MG) were used as indicators of renal dysfunction, and urinary cadmium (U-Cd) was used as indicator of total internal cadmium exposure. We made a hypothesis that soil cadmium concentration (S-Cd) and rice cadmium concentration (R-Cd) could be used as indicators of environmental cadmium exposure. Correlation and path analysis were used to estimate the relationships among the levels of rice cadmium (R-Cd), soil cadmium (S-Cd), urinary cadmium (U-Cd), and renal damage indicators (NAG and β2MG). Our results showed that there was positive significant relationship between S-Cd (R-Cd, U-Cd), and U-NAG (U-β2MG). The standard multiple regression describing the relationship between S-Cd (R-Cd, U-Cd) and U-NAG was Y1 = 1.26X1-6.53X2 + 9.32, where Y is U-NAG, X1 is U-Cd, X2 is S-Cd. The equation of U-β2MG was Y = 49.32X1 + 3085.99X2 + 143.42, where Y is U-β2MG, X1 is U-Cd, X2 is R-Cd. It is obvious that the effect of S-Cd and R-Cd on NAG or U-β2MG cannot be ignored. Through our study, we can find that the effects of S-Cd on renal health even as significant as R-Cd. To protect people from the damage of cadmium pollution, it is vital to monitor the situation of soil and rice cadmium pollution.

  16. Multisite adsorption of cadmium on goethite

    SciTech Connect

    Venema, P.; Hiemstra, T.; Riemsdijk, W.H. van

    1996-11-10

    Recently a new general ion adsorption model has been developed for ion binding to mineral surfaces (Hiemstra and van Riemsdijk, 1996). The model uses the Pauling concept of charge distribution (CD) and is an extension of the multi-site complexation (MUSIC) approach. In the CD-MUSIC model the charge of an adsorbing ion that forms an inner sphere complex is distributed over its ligands, which are present in two different electrostatic planes. In this paper the authors have applied the CD-MUSIC model to the adsorption of metal cations, using an extended data set for cadmium adsorbing on goethite. The adsorption of cadmium and the cadmium-proton exchange ratio were measured as function of metal ion concentration, pH, and ionic strength. The data could be described well, taking into account the surface heterogeneity resulting from the presence of two different crystal planes (the dominant 110 face and the minor 021 face). The surface species used in the model are consistent with recent EXAFS data. In accordance with the EXAFS results, high-affinity complexes at the 021 face were used in the model.

  17. Cadmium in soils and its transfer to plants and the human food chain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cadmium occurs naturally in all soils, but few soils contain higher than 1mg Cd kg-1. Most geogenic Cd is accompanied by 100-200 fold higher Zn except for marine shale or phosphorite derived soils which may have 1g Cd per 10g Zn or higher. Contamination by mining or smelter emissions of Zn-Pb-Cu i...

  18. Integrated management strategies for Arsenic and Cadmium in rice paddy environments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice is both a major staple food for human populations, and the major source of soil arsenic (As) and cadmium (Cd) transfer to the human food chain. Thus soil and crop accumulation of As and Cd have become major environmental issues globally. Arsenic and Cd contamination of soils and rice threatens ...

  19. Sulfur decreases cadmium translocation and enhances cadmium tolerance by promoting sulfur assimilation and glutathione metabolism in Brassica chinensis L.

    PubMed

    Liang, Taishuai; Ding, Han; Wang, Guodong; Kang, Jingquan; Pang, Hongxi; Lv, Jinyin

    2016-02-01

    We investigated the ameliorative role of sulfur (S) in protecting plants against cadmium (Cd) toxicity by using two pakchoi (Brassica chinensis L.) cultivars with different Cd tolerance levels. The exposure of pakchoi seedlings to 100μM Cd inhibited plant growth, increased superoxide content, enhanced membrane lipid peroxidation, and induced Cd accumulation in the roots and shoots. Application of S to Cd-stressed plants alleviated Cd-induced oxidative stress by promoting the capacity of the ascorbate (AsA)-glutathione (GSH) cycle, enhanced S assimilation by increasing the activity of ATP sulfurylase (ATPS) and o-acetylserine(thiol)lyase (OASTL), and decreased Cd translocation from the roots to the shoots by enhancing phytochelatins (PCs) biosynthesis. Results suggested that S reversed Cd-induced growth inhibition and oxidative stress by restraining Cd translocation from the roots to the shoots and upregulating S assimilation and GSH metabolism, including the AsA-GSH cycle and PCs synthesis.

  20. Cysteamine capped CdS quantum dots as a fluorescence sensor for the determination of copper ion exploiting fluorescence enhancement and long-wave spectral shifts

    NASA Astrophysics Data System (ADS)

    Boonmee, Chanida; Noipa, Tuanjai; Tuntulani, Thawatchai; Ngeontae, Wittaya

    2016-12-01

    We described a turn-on fluorescence sensor for the determination of Cu2 + ions, utilizing the quantum confinement effect of cadmium sulfide quantum dots capped with cysteamine (Cys-CdS QDs). The fluorescence intensity of the Cys-CdS QDs was both enhanced and red shifted (from blue-green to yellow) in the presence of Cu2 +. Fluorescence enhancement was linearly proportional to the concentration of Cu2 + in the concentration range 2 to 10 μM. Other cations at the same concentration level did not significantly change the intensity and spectral maxima of Cys-CdS QDs, except Ag+. The limit of detection was 1.5 μM. The sensor was applied to the determination of Cu2 + in (spiked) real water samples and gave satisfactory results, with recoveries ranging from 96.7 to 108.2%, and with RSDs ranging from 0.3 to 2.6%.

  1. EFFECTS OF BIOSOLIDS ON SORPTION AND DESORPTION BEHAVIOR OF CADMIUM IN BIOSOLIDS-AMENDED SOILS

    EPA Science Inventory

    Cadmium sorption and desorption experiments were conducted on different fractions of soils amended with different biosolids with varying chemical properties and unamended soil (control). Biosolids addition increased the slope of the Cd sorption isotherms compared to the control s...

  2. Maternal Cadmium, Iron and Zinc Levels, DNA Methylation and Birth Weight

    EPA Science Inventory

    BACKGROUND:Cadmium (Cd) is a ubiquitous and environmentally persistent toxic metal that has been implicated in neurotoxicity, carcinogenesis and obesity and essential metals including zinc (Zn) and iron (Fe) may alter these outcomes. However mechanisms underlying these relationsh...

  3. The use of 4-substituted pyridines to afford amphiphilic, pegylated cadmium selenide nanoparticles.

    PubMed

    Skaff, Habib; Emrick, Todd

    2003-01-07

    Amphiphilic cadmium selenide (CdSe) nanoparticles were prepared by surface functionalization with novel ligands 1 and 2, composed of pyridine moieties substituted in the 4-position with polyethylene glycol (PEG) chains.

  4. Cadmium neurotoxicity to a freshwater planarian.

    PubMed

    Wu, Jui-Pin; Lee, Hui-Ling; Li, Mei-Hui

    2014-11-01

    Although freshwater planarians are evolutionarily primitive, they are some of the simplest bilateral animals possessing integrated neural networks similar to those in vertebrates. We attempted to develop planarian Dugesia japonica as a model for investigating the neurotoxicity of environmental pollutants such as cadmium (Cd). This study was therefore designed to study the effects of Cd on the locomotor activity, neurobehavior, and neurological enzymes of D. japonica. After planarians were exposed to Cd at high concentrations, altered neurobehavior was observed that exhibited concentration-dependent patterns. Morphological alterations in Cd-treated planarians included irregular shape, body elongation, screw-like hyperkinesia, and bridge-like position. To study the direct effects of Cd on neurological enzymes, tissue homogenates of planarians were incubated in vitro with Cd before their activity was measured. Results showed that acetylcholinesterase (AChE), adenosine triphosphatase (ATPase), and monoamine oxidase A (MAO-A) activities were inhibited in a concentration-dependent manner. MAO-B activity was significantly induced by Cd at low concentrations and inhibited at high concentrations. Changes in the in vivo activity of AChE and ATPase were also found after planarians were treated with Cd at a sublethal concentration (5.56 μM). These observations indicate that neurotransmission systems in planarians are disturbed after Cd exposure.

  5. Cadmium, diabetes and chronic kidney disease

    SciTech Connect

    Edwards, Joshua R. Prozialeck, Walter C.

    2009-08-01

    Recent epidemiological studies suggest a positive association between exposure to the environmental pollutant cadmium (Cd) and the incidence and severity of diabetes. In this review, we examine the literature suggesting a relationship between Cd exposure, elevated blood glucose levels, and the development of diabetes. In addition we review human and animal studies indicating that Cd potentiates or exacerbates diabetic nephropathy. We also review the various possible cellular mechanisms by which Cd may alter blood glucose levels. In addition, we present some novel findings from our own laboratories showing that Cd elevates fasting blood glucose levels in an animal model of subchronic Cd exposure before overt signs of renal dysfunction are evident. These studies also show that Cd reduces insulin levels and has direct cytotoxic effects on the pancreas. Together, these findings indicate that Cd may be a factor in the development of some types of diabetes and they raise the possibility that Cd and diabetes-related hyperglycemia may act synergistically to damage the kidney.

  6. 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

    NASA Astrophysics Data System (ADS)

    Ding, De-Gang; Xie, Li-Xia; Fan, Yao-Ting; Hou, Hong-Wei; Xu, Yan

    2009-06-01

    Three new d10 coordination polymers, namely [Cd(taa)Cl] n1, [Hg(taa)Cl] n2, and [Ag 1.5(taa)(NO 3) 0.5] n3 (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 Schläfli 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 Schläfli 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.

  7. Cadmium-induced physiological response and antioxidant enzyme changes in the novel cadmium accumulator, Tagetes patula.

    PubMed

    Liu, Yu-Ting; Chen, Zueng-Sang; Hong, Chwan-Yang

    2011-05-30

    The accumulation and effect of cadmium (Cd) on the growth and enzymatic activities changes of antioxidants in Tagetes patula, French marigold, were investigated to reveal the physiological mechanisms corresponding to its Cd tolerance and accumulation. Hydroponically grown T. patula plants were treated with different concentrations of Cd (0, 10, 25, 50 μM Cd Cl(2)) at various regime of times. T. patula accumulated Cd to a maximum of 450 mg Cd kg(-1) dry weight (DW) in shoot and 3500 mg Cd kg(-1) DW in root after 14 days' exposure at 10 and 50 μM Cd Cl(2), respectively. The translocation factors of Cd were greater than 1 in plants exposed to 10 μM Cd Cl(2). Toxic effects were gradually observed with increasing Cd concentration (25 and 50 μM) accompanied with the reduction of biomass, chlorophyll content, decrease of cell viability and the increase level of lipid peroxidation. In leaves of T. patula, the activities of ascorbate peroxidase (APX), glutathione reductase (GR) and superoxide dismutase (SOD) were induced by Cd. However, in roots, activities of APX, GR, SOD and catalase (CAT) were significantly reduced by 25 and 50 μM Cd treatment but not 10 μM Cd. In-gel zymography analysis revealed that Cd induced the enzymatic activities of APX, MnSOD, CuZnSOD and different isozymes of GR in leaves. These results indicate that T. patula is a novel Cd accumulator and able to tolerate with Cd-induced toxicity by activation of its antioxidative defense system.

  8. The Precise Determination of Cd Isotope Ratio in Geological Samples by MC-ICP-MS with Ion Exchange Separation

    NASA Astrophysics Data System (ADS)

    Du, C.; Hu, S.; Wang, D.; Jin, L.; Guo, W.

    2014-12-01

    Cadmium (Cd) is a trace element which occurs at μg g-1 level abundances in the crust. Cd isotopes have great prospects in the study of the cosmogony, the trace of anthropogenic sources, the micronutrient cycling and the ocean productivity. This study develops an optimized technique for the precise and accurate determination of Cd isotopic compositions. Cd was separated from the matrix by elution with AG-MP-1 anionic exchange chromatographic resin. The matrix elements (K, Na, Ca, Al, Fe, and Mg etc.), polyatomic interfered elements (Ge, Ga, Zr, Nb, Ru, and Mo), and isobaric interfered elements (In, Pd and most of Sn) were eluted using HCl with gradient descent concentrations (2, 0.3, 0.06, 0.012 and 0.0012 mol L-1). The same elution procedure was repeated to eliminate the residuel Sn (Sn/Cd < 0.018). The collected Cd was analyzed using MC-ICP-MS, in which the instrumental mass fractionation was controlled by a "sample-standard bracketing" technique. The recovery of Cd larger than 96.85%, and the δ114/110Cd are in the range of -1.43~+0.20‰ for ten geological reference materials (GSD-3a, GSD-5a, GSD-7a, GSD-6, GSD-9, GSD-10, GSD-11, GSD-12, GSD-23, and GSS-1). The δ114/110Cd obtained for GSS-1 soil sample relative to the NIST SRM 3108 Cd solution was 0.20, which was coherent with the literature values (0.08±0.23). This method had a precision of 0.001~0.002% (RSD), an error range of 0.06~0.14 (δ114/110Cd, 2σ), and a long-term reproducibility of 0.12 (δ114/110Cd, 2σ).

  9. Cadmium toxicity induced alterations in the root proteome of green gram in contrasting response towards iron supplement.

    PubMed

    Muneer, Sowbiya; Hakeem, Khalid Rehman; Mohamed, Rozi; Lee, Jeong Hyun

    2014-04-15

    Cadmium signifies a severe threat to crop productivity and green gram is a notably iron sensitive plant which shows considerable variation towards cadmium stress. A gel-based proteomics analysis was performed with the roots of green gram exposed to iron and cadmium combined treatments. The resulting data show that twenty three proteins were down-regulated in iron-deprived roots either in the absence (-Fe/-Cd) or presence (-Fe/+Cd) of cadmium. These down-regulated proteins were however well expressed in roots under iron sufficient conditions, even in the presence of cadmium (+Fe/+Cd). The functional classification of these proteins determined that 21% of the proteins are associated with nutrient metabolism. The other proteins in higher quantities are involved in either transcription or translation regulation, and the rest are involved in biosynthesis metabolism, antioxidant pathways, molecular chaperones and stress response. On the other hand, several protein spots were also absent in roots in response to iron deprivation either in absence (-Fe/-Cd) or presence (-Fe/+Cd) of cadmium but were well expressed in the presence of iron (+Fe/+Cd). Results suggest that green gram plants exposed to cadmium stress are able to change the nutrient metabolic balance in roots, but in the mean time regulate cadmium toxicity through iron supplements.

  10. Cadmium Toxicity Induced Alterations in the Root Proteome of Green Gram in Contrasting Response towards Iron Supplement

    PubMed Central

    Muneer, Sowbiya; Hakeem, Khalid Rehman; Mohamed, Rozi; Lee, Jeong Hyun

    2014-01-01

    Cadmium signifies a severe threat to crop productivity and green gram is a notably iron sensitive plant which shows considerable variation towards cadmium stress. A gel-based proteomics analysis was performed with the roots of green gram exposed to iron and cadmium combined treatments. The resulting data show that twenty three proteins were down-regulated in iron-deprived roots either in the absence (−Fe/−Cd) or presence (−Fe/+Cd) of cadmium. These down-regulated proteins were however well expressed in roots under iron sufficient conditions, even in the presence of cadmium (+Fe/+Cd). The functional classification of these proteins determined that 21% of the proteins are associated with nutrient metabolism. The other proteins in higher quantities are involved in either transcription or translation regulation, and the rest are involved in biosynthesis metabolism, antioxidant pathways, molecular chaperones and stress response. On the other hand, several protein spots were also absent in roots in response to iron deprivation either in absence (−Fe/−Cd) or presence (−Fe/+Cd) of cadmium but were well expressed in the presence of iron (+Fe/+Cd). Results suggest that green gram plants exposed to cadmium stress are able to change the nutrient metabolic balance in roots, but in the mean time regulate cadmium toxicity through iron supplements. PMID:24739807

  11. CD3[sup [minus

    SciTech Connect

    Wong, J.G.P.; Nalefski, E.A. ); Kasibhatla, S.; Rao, A. )

    1992-12-15

    Mutants of an untransformed T cell clone that no longer respond to TCR/CD3 stimulation have been derived using a selection procedure based on the loss of functional response to Ag. This functional selection gives rise to clones of several different phenotypes. The authors have previously described mutants with a TCR/CD3[sup +] cell surface phenotype whose TCR are uncoupled from cellular responses. They describe six additional mutants that do not express TCR/CD3 at the cell surface. One of the CD3[sup [minus

  12. Process for producing cadmium sulfide on a cadmium telluride surface

    DOEpatents

    Levi, D.H.; Nelson, A.J.; Ahrenkiel, R.K.

    1996-07-30

    A process is described for producing a layer of cadmium sulfide on a cadmium telluride surface to be employed in a photovoltaic device. The process comprises providing a cadmium telluride surface which is exposed to a hydrogen sulfide plasma at an exposure flow rate, an exposure time and an exposure temperature sufficient to permit reaction between the hydrogen sulfide and cadmium telluride to thereby form a cadmium sulfide layer on the cadmium telluride surface and accomplish passivation. In addition to passivation, a heterojunction at the interface of the cadmium sulfide and the cadmium telluride can be formed when the layer of cadmium sulfide formed on the cadmium telluride is of sufficient thickness. 12 figs.

  13. Statolith formation in Cnidaria: effects of cadmium on Aurelia statoliths

    NASA Technical Reports Server (NTRS)

    Spangenberg, D. B.

    1986-01-01

    Statolith formation in Cnidaria was reviewed with an emphasis on Aurelia statoliths. The review provides information on the chemical composition, mechanisms of initiation of mineralization, and effects of environmental factors on Cnidarian statolith formation. Environmental factors discussed included modified sea water ingredients, X-irradiation, clinostat rotation, and petroleum oil ingredients. A detailed account of the effects of cadmium on mineralization and demineralization of Aurelia statoliths is given. Cadmium at dosages of 2 to 4 micromoles significantly reduces statolith numbers in developing ephyrae. At a dosage of 3 micromoles, cadmium accelerates statolith loss in unfed ephyrae studied at 4 and 8 days following ephyrae release from strobilae. Cadmium, therefore, is shown to reduce statolith numbers in developing ephyrae and to cause greater reduction of statolith numbers in unfed ephyrae after 4 and 8 days than occurred in controls. Supplementation of Cd(2+)-containing artificial sea water (ASW) with calcium (3X and 5X ASW calcium content) results in higher numbers of statoliths at day 4 as compared with cadmium-treated ephyrae. At 8 days only the 5X calcium supplemented ASW is effective in enhancing statolith numbers in Cd(2+)-treated ephyrae. These results suggest that cadmium competes in some manner with calcium at the mineralizing sites of Aurelia.

  14. Cadmium and lithium doping in silver orthophosphate: An ab initio study

    PubMed Central

    Huang, Yang; Liu, Ming-Yang; Ma, Tai; Lou, Zhong-Ping; Cao, Chao; He, Yao

    2016-01-01

    Using hybrid functional calculations, we investigate the effects of defects and defect complexes related with Cd, Li, and N impurities on the atomic and electronic properties of Ag3PO4. It was found that substitutional Cd on Ag lattice site (CdAg) contributes to the n-type conductivity of Ag3PO4. For substitutional Cd on P (or O) lattice site (CdP) (or CdO), it is not expected that Cd will incorporate into the P (or O) site due to the strong covalent interactions in the PO4 structural units. The interstitial Cd (Cdi) acts as a shallow donor, but its formation energy is relatively high compared with that of CdAg. For the (CdAg-2NO) complex, the formation of this inactive complex generates a fully occupied impurity band just above the valence band maximum of Ag3PO4, which significantly reduces the acceptor transition energy level. But the formation energy of the (CdAg-2NO) complex is even higher than that of the corresponding single point defect NO. Unlike LiP and LiO which has relatively high formation energy, interstitial Li (Lii or Lii(s)) with an appreciable solubility is likely to be the n-type dopant under O-poor condition. PMID:27576491

  15. Cadmium(II) complex formation with cysteine and penicillamine.

    PubMed

    Jalilehvand, Farideh; Leung, Bonnie O; Mah, Vicky

    2009-07-06

    The complex formation between cadmium(II) and the ligands cysteine (H(2)Cys) and penicillamine (H(2)Pen = 3,3'-dimethylcysteine) in aqueous solutions, having C(Cd(II)) approximately 0.1 mol dm(-3) and C(H(2)L) = 0.2-2 mol dm(-3), was studied at pH = 7.5 and 11.0 by means of (113)Cd NMR and Cd K- and L(3)-edge X-ray absorption spectroscopy. For all cadmium(II)-cysteine molar ratios, the mean Cd-S and Cd-(N/O) bond distances were found in the ranges 2.52-2.54 and 2.27-2.35 A, respectively. The corresponding cadmium(II)-penicillamine complexes showed slightly shorter Cd-S bonds, 2.50-2.53 A, but with the Cd-(N/O) bond distances in a similar wide range, 2.28-2.33 A. For the molar ratio C(H(2)L)/C(Cd(II)) = 2, the (113)Cd chemical shifts, in the range 509-527 ppm at both pH values, indicated complexes with distorted tetrahedral CdS(2)N(N/O) coordination geometry. With a large excess of cysteine (molar ratios C(H(2)Cys)/C(Cd(II)) >or= 10), complexes with CdS(4) coordination geometry dominate, consistent with the (113)Cd NMR chemical shifts, delta approximately 680 ppm at pH 7.5 and 636-658 ppm at pH 11.0, and their mean Cd-S distances were 2.53 +/- 0.02 A. At pH 7.5, the complexes are almost exclusively sulfur-coordinated as [Cd(S-cysteinate)(4)](n-), while at higher pH, the deprotonation of the amine groups promotes chelate formation. At pH 11.0, a minor amount of the [Cd(Cys)(3)](4-) complex with CdS(3)N coordination is formed. For the corresponding penicillamine solutions with molar ratios C(H(2)Pen)/C(Cd(II)) >or= 10, the (113)Cd NMR chemical shifts, delta approximately 600 ppm at pH 7.5 and 578 ppm at pH 11.0, together with the average bond distances, Cd-S 2.53 +/- 0.02 A and Cd-(N/O) 2.30-2.33 A, indicate that [Cd(penicillaminate)(3)](n-) complexes with chelating CdS(3)(N/O) coordination dominate already at pH 7.5 and become mixed with CdS(2)N(N/O) complexes at pH 11.0. The present study reveals differences between cysteine and penicillamine as ligands to the

  16. Combined effects of cadmium and salinity on juvenile Takifugu obscurus: cadmium moderates salinity tolerance; salinity decreases the toxicity of cadmium

    PubMed Central

    Wang, Jun; Zhu, Xuexia; Huang, Xin; Gu, Lei; Chen, Yafen; Yang, Zhou

    2016-01-01

    Obscure puffer Takifugu obscurus, a species of anadromous fish, experiences several salinity changes in its lifetime. Cadmium (Cd) is a toxic heavy metal that can potentially induce oxidative stress in fish. The present study aimed to detect the combined effects of Cd (0, 5, 10, 20 and 50 mg L−1) and salinity (0, 15 and 30 ppt) on juvenile T. obscurus. Results showed the juveniles could survive well under different salinities; however, with Cd exposure, the survival rates significantly decreased at 0 and 30 ppt. At 15 ppt, tolerance to Cd increased. Cd exposure clearly induced oxidative stress, and the responses among different tissues were qualitatively similar. Salinity acted as a protective factor which could reduce the reactive oxygen species and malondialdehyde levels. In addition, salinity could enhance the antioxidant defense system, including superoxide dismutase, catalase and glutathione. Na+/K+–ATPase activity significantly decreased under Cd exposure in gill, kidney and intestine. These findings indicated that Cd could moderate the adaptability of juvenile T. obscurus to high salinity and low salinity played a protective role upon Cd exposure. Thus, the role of salinity should be considered when evaluating the effect of heavy metals on anadromous and estuarine fishes. PMID:27487764

  17. Phase equilibria in the neodymium–cadmium binary system

    PubMed Central

    Skołyszewska-Kühberger, Barbara; Reichmann, Thomas L.; Ipser, Herbert

    2014-01-01

    The equilibrium phase diagram of the neodymium–cadmium system has been established by thermal, metallographic and X-ray analysis based on a study of 70 alloys. The system contains three congruently melting intermetallic compounds, i.e. NdCd (1040 °C), NdCd2 (995 °C), Nd11Cd45 (855 °C), and four incongruently melting compounds NdCd3 (860 °C), Nd13Cd58 (740 °C), NdCd6 (655 °C) and NdCd11 (520 °C). Four eutectic reactions are found in this binary system, i.e. at ∼25 at.% Cd and 770 °C, at 58 at.% Cd and 955 °C, at 79 at.% Cd and 850 °C, and very close to pure Cd at 318 °C, as well as one eutectoid reaction at ∼15 at.% Cd and 500 °C. The solid solubility of Nd in Cd is negligible. Dilatometric curves were recorded for three Nd–Cd compositions up to 4 at.% Cd, to accurately determine phase transitions between the solid solutions of Cd in the low- and high-temperature modification of Nd. PMID:25197164

  18. Phase equilibria in the neodymium-cadmium binary system.

    PubMed

    Skołyszewska-Kühberger, Barbara; Reichmann, Thomas L; Ipser, Herbert

    2014-09-05

    The equilibrium phase diagram of the neodymium-cadmium system has been established by thermal, metallographic and X-ray analysis based on a study of 70 alloys. The system contains three congruently melting intermetallic compounds, i.e. NdCd (1040 °C), NdCd2 (995 °C), Nd11Cd45 (855 °C), and four incongruently melting compounds NdCd3 (860 °C), Nd13Cd58 (740 °C), NdCd6 (655 °C) and NdCd11 (520 °C). Four eutectic reactions are found in this binary system, i.e. at ∼25 at.% Cd and 770 °C, at 58 at.% Cd and 955 °C, at 79 at.% Cd and 850 °C, and very close to pure Cd at 318 °C, as well as one eutectoid reaction at ∼15 at.% Cd and 500 °C. The solid solubility of Nd in Cd is negligible. Dilatometric curves were recorded for three Nd-Cd compositions up to 4 at.% Cd, to accurately determine phase transitions between the solid solutions of Cd in the low- and high-temperature modification of Nd.

  19. Determination of the homogeneity region of cadmium selenide

    SciTech Connect

    Brezhnev, V.Yu.; Kharif, Ya.L.; Kovtunenko, P.V.

    1987-10-01

    The purpose of the authors paper is refinement of the limit of the homogeneity region of cadmium selenide. The method of extraction of cadmium into the vapor phase was used to determine the cadmium content in cadmium selenide. At 870/sup 0/K the equilibrium of the cadmium selenide crystals during saturation by cadmium was monitored according to the reproducibility (in the range of +/-15%) of the results of experiments of different durations (30, 46, 62, and 192 h). Since at 870/sup 0/K the equilibrium was established in 30 h, at higher temperatures the duration of the annealing was assumed to be 30 h. In addition, in experiments at 1270 and 1370 K, crystals with thicknesses from 200 to 1500 ..mu..m were saturated simultaneously. The solubility of cadmium in CdSe was found to be 0.00053-0.00071 at. % at 870/sup 0/K, 0.0073-0.0113 at. % at 1170/sup 0/K, 0.022 at. % at 1270 K, 0.038 at. % at 1320/sup 0/K, and 0.044 at. % at 1370/sup 0/K.itrified

  20. Oxidant and antioxidant status of cadmium administered rats

    NASA Astrophysics Data System (ADS)

    Toplan, S.; Ozcelik, D.; Dariyerli, N.; Akyolcu, M. C.

    2003-05-01

    Cadmium is one of the industrial elements that lead environmental pollution. Biological half-life of cadmium is relatively longer, so its clearance from tissue is considerably long. In present study, oxidant stress and antioxidant defense mechanism due to exposure to cadmium in rats wanted to be investigated. For such a purpose adult female wistar albino rats were divided into two as control and experimental groups. During experimental period while both group animals were fed by standard fodder, cadmium added (20 μg Cd/ml as cadmium sulfate) drinking water was given to experimental group for four weeks. At the end of four weeks blood samples were drawn from animals under ether anesthesia. As a Last product of lipid peroxidation malondialdehyde (MDA) level, superoxide dismutas (SOD) activity which is sign of antioxidant defense enzyme activity and glutathione levels (GSH) were measured. Increase in lipid peroxidation has been observed by increased MDA levels in experimental group (p<0.001). SOD enzyme activity was also found to be significantly lower in experimental group (p<0.001). Glutathione level of experimental group found to be decreased according to control group values (p<0.01). As a result of present study it may be concluded that cadmium may lead to increase in lipid peroxidation. On the other hand SOD activity and glutathione levels may also be decreased by effect of cadmium in erythrocytes. So the resultant would be the disturbed antioxidant mechanism

  1. A rapid, partial leach and organic separation for the sensitive determination of Ag, Bi, Cd, Cu, Mo, Pb, Sb, and Zn in surface geologic materials by flame atomic absorption

    USGS Publications Warehouse

    Viets, J.G.; Clark, J.R.; Campbell, W.L.

    1984-01-01

    A solution of dilute hydrochloric acid, ascorbic acid, and potassium iodide has been found to dissolve weakly bound metals in soils, stream sediments, and oxidized rocks. Silver, Bi, Cd, Cu, Mo, Pb, Sb, and Zn are selectively extracted from this solution by a mixture of Aliquat 336 (tricaprylyl methyl ammonium chloride) and MIBK (methyl isobutyl ketone). Because potentially interfering major and minor elements do not extract, the organic separation allows interference-free determinations of Ag and Cd to the 0.05 ppm level, Mo, Cu, and Zn to 0.5 ppm, and Bi, Pb, and Sb to 1 ppm in the sample using flame atomic absorption spectroscopy. The analytical absorbance values of the organic solution used in the proposed method are generally enhanced more than threefold as compared to aqueous solutions, due to more efficient atomization and burning characteristics. The leaching and extraction procedures are extremely rapid; as many as 100 samples may be analyzed per day, yielding 800 determinations, and the technique is adaptable to field use. The proposed method was compared to total digestion methods for geochemical reference samples as well as soils and stream sediments from mineralized and unmineralized areas. The partial leach showed better anomaly contrasts than did total digestions. Because the proposed method is very rapid and is sensitive to pathfinder elements for several types of ore deposits, it should be useful for reconnaissance surveys for concealed deposits. ?? 1984.

  2. Cadmium Distribution and Chemical Fate in Soybean Plants 1

    PubMed Central

    Cataldo, Dominic A.; Garland, Thomas R.; Wildung, Raymond E.

    1981-01-01

    The distribution and chemical behavior of Cd2+ in tissues and its chemical form in xylem water of soybean plants (cv. Williams) were investigated. Following root absorption, Cd is strongly retained by roots, with only 2% of the accumulated Cd being transported to leaves; as much as 8% was transported to seeds during seed filling. In vivo xylem exudates contained two anionic Cd complexes in addition to inorganic forms of Cd. Once accumulated in root and leaf tissues, Cd rapidly equilibrated between the insoluble, soluble, and organelle fractions. Of the solubles, which contain 50% of the Cd, >50% was associated with components of >10,000 molecular weight, and <8% was associated with <500 molecular weight components. Cadmium accumulated in soybean seeds was primarily associated with cotyledons. Fractionation of seeds showed the soy proteinate and soy whey to contain 32 and 50% of the accumulated Cd, respectively. PMID:16662008

  3. Tolerance of Ricinus communis L. to Cd and screening of high Cd accumulation varieties for remediation of Cd contaminated soils.

    PubMed

    Wu, Shanshan; Shen, Chuang; Yang, Zhongyi; Lin, Biyun; Yuan, Jiangang

    2016-11-01

    Response of castor (Ricinus communis L.) to cadmium (Cd) was assessed by a seed-suspending seedbed approach. Length of total radicle was the most sensitive indicator of Cd tolerance among the tested germination and growth characters. The ED50 value for Cd was 11.87 mg L(-1), indicating high Cd tolerance in castor. A pot experiment was conducted by growing 46 varieties of castor under CK (without Cd) and Cd1 (10 mg kg(-1) of Cd) and Cd2 (50 mg kg(-1) of Cd) treatments to investigate genotype variations in growth response and Cd accumulation of castor under different Cd exposures. Castor possessed high Cd accumulation ability; average shoot and root Cd concentrations of the 46 tested varieties were 21.83 and 185.43 mg kg(-1), and 174.99 and 1181.96 mg kg(-1) under Cd1 and Cd2, respectively. Great variation in Cd accumulation was observed among varieties, and Cd concentration of castor was genotype dependent. The correlation between biomass and Cd accumulation was significantly positive, while no significant correlation was observed between Cd concentration and Cd accumulation, which indicated that biomass performance is the dominant factor in determining Cd accumulation ability.

  4. A biosensor for cadmium based on bioconvective patterns

    NASA Technical Reports Server (NTRS)

    Noever, David A.; Matsos, Helen C.

    1990-01-01

    An 'in vitro' method for monitoring cadmium, one of the most lethal bivalent heavy metals, can detect biologically active levels. The effects of cadmium tend to concentrate in protozoa far above natural levels and therein begin transferring through freshwater food chains to animals and humans. In a small sample volume (approximately 5 ml) the method uses the toxic response to the protozoa, Tetrahymena pyriformis, to cadmium. The assay relies on macroscopic bioconvective patterns to measure the toxic response, giving a sensitivity better than 1 micro-g/1 and a toxicity threshold to 7 micro-g/1 for Cd(2+). Cadmium hinders pattern formation in a dose-dependent manner. Arrested organism growth arises from slowed division and mutation to non-dividing classes. Unlike previous efforts, this method can be performed in a shallow flow device and does not require electronic or chemical analyses to monitor toxicity.

  5. Changes in cadmium mobility during composting and after soil application

    SciTech Connect

    Hanc, Ales Tlustos, Pavel; Szakova, Jirina; Habart, Jan

    2009-08-15

    The effect of twelve weeks of composting on the mobility and bioavailability of cadmium in six composts containing sewage sludge, wood chips and grass was studied, along with the cadmium immobilization capacity of compost. Two different soils were used and Cd accumulation measured in above-ground oat biomass (Avena sativa L.). Increasing pH appears to be an important cause of the observed decreases in available cadmium through the composting process. A pot experiment was performed with two different amounts of compost (9.6 and 28.8 g per kg of soil) added into Fluvisol with total Cd 0.255 mg kg{sup -1}, and contaminated Cambisol with total Cd 6.16 mg kg{sup -1}. Decrease of extractable Cd (0.01 mol l{sup -1} CaCl{sub 2}) was found in both soils after compost application. The higher amount of compost immobilized an exchangeable portion of Cd (0.11 mol l{sup -1} CH{sub 3}COOH extractable) in contaminated Cambisol unlike in light Fluvisol. The addition of a low amount of compost decreased the content of Cd in associated above-ground oat biomass grown in both soils, while a high amount of compost decreased the Cd content in oats only in the Cambisol.

  6. Nonstoichiometry of crystalline cadmium selenide

    SciTech Connect

    Kharif, Ya.L.; Brezhnev, V.Yu.; Kovtunenko, P.V.

    1987-08-01

    A highly sensitive physicochemical method is developed for determining the cadmium concentration (10/sup -5/ at. % for a 10 g sample weight), dissolved in cadmium selenide. The nonstoichiometry of cadmium selenide crystals is studied after high-temperature annealing at 870-1370/sup 0/K in cadmium vapor. For the first time, it is discovered that in the investigated crystals the dissolved cadmium exists primarily in the form of electrically neutral defects, which are presumably clusters of selenium vacancies with low mobility.

  7. Effects of Different Dietary Cadmium Levels on Growth and Tissue Cadmium Content in Juvenile Parrotfish, Oplegnathus fasciatus

    PubMed Central

    Okorie, Okorie E.; Bae, Jun Young; Lee, Jun-Ho; Lee, Seunghyung; Park, Gun-Hyun; Mohseni, Mahmoud; Bai, Sungchul C.

    2014-01-01

    This feeding trial was carried out to evaluate the effects of different dietary cadmium levels on growth and tissue cadmium content in juvenile parrotfish, Oplegnathus fasciatus, using cadmium chloride (CdCl2) as the cadmium source. Fifteen fish averaging 5.5±0.06 g (mean±SD) were randomly distributed into each of twenty one rectangular fiber tanks of 30 L capacity. Each tank was then randomly assigned to one of three replicates of seven diets containing 0.30 (C0), 21.0 (C21), 40.7 (C41), 83.5 (C83), 162 (C162), 1,387 (C1,387) and 2,743 (C2,743) mg cadmium/kg diet. At the end of sixteen weeks of feeding trial, weight gain (WG), specific growth rate (SGR) and feed efficiency (FE) of fish fed C21 were significantly higher than those of fish fed C83, C162, C1,387 and C2,743 (p<0.05). Weight gain, SGR and FE of fish fed C0, C21 and C41 were significantly higher than those of fish fed C162, C1,387 and C2,743. Protein efficiency ratio of fish fed C0, C21 and C41 were significantly higher than those of fish fed C1,387 and C2,743. Average survival of fish fed C0, C21, C41 and C162 were significantly higher than that of fish fed C2,743. Tissue cadmium concentrations increased with cadmium content of diets. Cadmium accumulated the most in liver, followed by gill and then muscle. Muscle, gill and liver cadmium concentrations of fish fed C0, C21, C41 and C83 were significantly lower than those of fish fed C162, C1,387 and C2,743. Based on the ANOVA results of growth performance and tissue cadmium concentrations the safe dietary cadmium level could be lower than 40.7 mg Cd/kg diet while the toxic level could be higher than 162 mg Cd/kg diet. PMID:25049927

  8. Effects of Different Dietary Cadmium Levels on Growth and Tissue Cadmium Content in Juvenile Parrotfish, Oplegnathus fasciatus.

    PubMed

    Okorie, Okorie E; Bae, Jun Young; Lee, Jun-Ho; Lee, Seunghyung; Park, Gun-Hyun; Mohseni, Mahmoud; Bai, Sungchul C

    2014-01-01

    This feeding trial was carried out to evaluate the effects of different dietary cadmium levels on growth and tissue cadmium content in juvenile parrotfish, Oplegnathus fasciatus, using cadmium chloride (CdCl2) as the cadmium source. Fifteen fish averaging 5.5±0.06 g (mean±SD) were randomly distributed into each of twenty one rectangular fiber tanks of 30 L capacity. Each tank was then randomly assigned to one of three replicates of seven diets containing 0.30 (C0), 21.0 (C21), 40.7 (C41), 83.5 (C83), 162 (C162), 1,387 (C1,387) and 2,743 (C2,743) mg cadmium/kg diet. At the end of sixteen weeks of feeding trial, weight gain (WG), specific growth rate (SGR) and feed efficiency (FE) of fish fed C21 were significantly higher than those of fish fed C83, C162, C1,387 and C2,743 (p<0.05). Weight gain, SGR and FE of fish fed C0, C21 and C41 were significantly higher than those of fish fed C162, C1,387 and C2,743. Protein efficiency ratio of fish fed C0, C21 and C41 were significantly higher than those of fish fed C1,387 and C2,743. Average survival of fish fed C0, C21, C41 and C162 were significantly higher than that of fish fed C2,743. Tissue cadmium concentrations increased with cadmium content of diets. Cadmium accumulated the most in liver, followed by gill and then muscle. Muscle, gill and liver cadmium concentrations of fish fed C0, C21, C41 and C83 were significantly lower than those of fish fed C162, C1,387 and C2,743. Based on the ANOVA results of growth performance and tissue cadmium concentrations the safe dietary cadmium level could be lower than 40.7 mg Cd/kg diet while the toxic level could be higher than 162 mg Cd/kg diet.

  9. New aspects of cadmium as endocrine disruptor.

    PubMed

    Takiguchi, Masufumi; Yoshihara, Shin'ichi

    2006-01-01

    Cadmium (Cd) is an industrial and environmental pollutant that exerts adverse effects on a number of organs in humans and animals. Reproductive organs, such as the testis and placenta, are sensitive to the toxic effects of Cd. In animal experiments, high-dose exposure to Cd induced severe testicular interstitial hemorrhage with edema, and increased incidence of fetal death and placental necrosis. Low-dose exposure to Cd affects steroid synthesis in male and female reproductive organs. In 1998, the Ministry of Environment in Japan listed Cd in the strategy plan SPEED98 as one of the chemicals suspected of having possible endocrine disrupting activity. Recently, it has been shown that Cd has potent estrogen- and androgen-like activities in vivo and in vitro, by directly binding to estrogen and androgen receptors. However, the precise mechanisms underlying the effects of Cd as an endocrine disruptor remain to be elucidated. In this review, we will discuss evidence thus far presented concerning the effects of Cd on the endocrine system.

  10. Striking association between urinary cadmium level and albuminuria among Torres Strait Islander people with diabetes

    SciTech Connect

    Haswell-Elkins, Melissa Satarug, Soisungwan; O'Rourke, Peter; Moore, Michael; Ng, Jack; McGrath, Victor; Walmby, Maria

    2008-03-15

    Objectives: Indigenous people of the Torres Strait (Australia) have greater potential for cadmium exposure and renal damage than other Australians due to high cadmium in some traditional seafood and a high prevalence of Type 2 diabetes, hypertension, smoking, and obesity. This study explored associations between albuminuria and an index of cadmium exposure (urinary cadmium excretion) in the presence and absence of Type 2 diabetes. Research design and methods: Two population-based, cross-sectional studies were undertaken in the Torres Strait to obtain data on body mass index (BMI), blood pressure, chronic disease, smoking, urinary cadmium, and albumin creatinine ratio (ACR). Results: Age- and BMI-adjusted urinary cadmium levels were significantly higher (p<0.01) among people with diabetes and albuminuria (n=22, geometric mean (GM) 1.91 {mu}g Cd/g creatinine) compared to those with diabetes and normal ACR (n=21, GM 0.74 {mu}g Cd/g creatinine). Urinary cadmium was also strongly associated (p<0.001) with ACR among people with diabetes in regression models and remained significant after controlling for age, sex, BMI, smoking status, and hypertension (or continuous systolic and diastolic measurements). Conclusions: While the study has methodological limitations and the nature of the association is unclear, the striking dose-dependent links between markers of cadmium exposure and of Type 2 diabetic nephropathy highlight the need for further definitive research on the health effects of cadmium in the presence of diabetes.

  11. Health, safety and environmental issues relating to cadmium usage in photovoltaic energy systems

    SciTech Connect

    Moskowitz, P.D.; Fthenakis, V.M. ); Zweibel, K. )

    1989-12-01

    This paper discusses the current technology base and hazards associated with two promising thin-film photovoltaic cells that contain cadmium compounds -- cadmium telluride (CdTe) and copper indium diselenide (CuInSe{sub 2}). More specifically, this paper summarizes the toxicological information on cadmium (Cd) compounds; evaluates potential health, safety and environmental hazards associated with cadmium usage in the photovoltaics industry; describes regulatory requirements associated with the use, handling and disposal of cadmium compounds; and lists management options to permit the safe and continued use of these materials. Handling of cadmium in photovoltaic production can present hazards to health, safety and the environment. Prior recognition of these hazards can allow device manufacturers and regulators to implement appropriate and readily available hazard management strategies. Hazards associated with product use (i.e., array fires) and disposal remain controversial and partially unresolved. The most likely effects that could be expected would be those associated with chronic low-level exposures to cadmium wastes. Because of the general immobility of the cadmium present in these devices and availability of environmental and biomonitoring protocols, chronic hazards can be monitored, and remediated if necessary. Nevertheless, concern about cadmium hazards should continue to be emphasized to ensure that health, safety and environmental issues are properly managed. At the same time, the potential role that these systems can play in ameliorating some important health and environmental hazards related to other energy systems should not be ignored. 27 refs., 5 figs., 2 tabs.

  12. Prediction of cadmium concentration in selected home-produced vegetables.

    PubMed

    Bešter, Petra Karo; Lobnik, Franc; Eržen, Ivan; Kastelec, Damijana; Zupan, Marko

    2013-10-01

    Soil contaminated with cadmium presents a potential hazard for humans, animals and plants. The latter play a major role in the transfer of cadmium to the food chain. The uptake of cadmium and its accumulation by plants is dependent on various soil, plants and environmental factors. In order to identify soil properties with statistically significant influence on cadmium concentration in vegetables and to reduce the collection of data, time and costs, regression models can be applied. The main objective of this research was to develop regression models to predict the concentration of cadmium in 9-vegetable species: zucchini, tomato, cabbage, onion, potato, carrot, red beet, endive and chicory, based on soil properties. Soil samples were collected from 123 home gardens of the Municipality of Celje and 59 of these gardens were also included in vegetable sampling. The concentration of elements (e.g. arsenic, cadmium, copper, lead, and zinc) in the samples was determined by Inductively Coupled Plasma Mass Spectrometry. Single (for cabbage, potato, red beet and chicory) and multiple (for tomato, onion, carrot and endive) linear regression models were developed. There was no statistically significant regression model for zucchini. The most significant parameter for the influencing the cadmium concentration in vegetables was the concentration of cadmium in soil. Other important soil properties were the content of organic matter, pH-value and the concentration of manganese. It was concluded that consuming carrots, red beets, endives, onions, potatoes and chicory which are grown in gardens with Cd concentrations (mgkg(-1) DW) above 2.4, 3.2, 6.3, 7.9, 8.3 and 10.9, respectively, might represent an important contribution to dietary Cd exposure.

  13. Theory and practical considerations of multilayer dielectric thin-film stacks in Ag-coated hollow waveguides.

    PubMed

    Bledt, Carlos M; Melzer, Jeffrey E; Harrington, James A

    2014-02-01

    This analysis explores the theory and design of dielectric multilayer reflection-enhancing thin film stacks based on high and low refractive index alternating layers of cadmium sulfide (CdS) and lead sulfide (PbS) on silver (Ag)-coated hollow glass waveguides (HGWs) for low loss transmission at midinfrared wavelengths. The fundamentals for determining propagation losses in such multilayer thin-film-coated Ag hollow waveguides is thoroughly discussed, and forms the basis for further theoretical analysis presented in this study. The effects on propagation loss resulting from several key parameters of these multilayer thin film stacks is further explored in order to bridge the gap between results predicted through calculation under ideal conditions and deviations from such ideal models that often arise in practice. In particular, the effects on loss due to the number of dielectric thin film layers deposited, deviation from ideal individual layer thicknesses, and surface roughness related scattering losses are presented and thoroughly investigated. Through such extensive theoretical analysis the level of understanding of the underlying loss mechanisms of multilayer thin-film Ag-coated HGWs is greatly advanced, considerably increasing the potential practical development of next-generation ultralow-loss mid-IR Ag/multilayer dielectric-coated HGWs.

  14. Betaine supplementation protects against renal injury induced by cadmium intoxication in rats: role of oxidative stress and caspase-3.

    PubMed

    Hagar, Hanan; Al Malki, Waleed

    2014-03-01

    Cadmium (Cd) is an environmental and industrial pollutant that can induce a broad spectrum of toxicological effects that affect various organs in humans and experimental animals. This study aims to investigate the effect of betaine supplementation on cadmium-induced oxidative impairment in rat kidney. The animals were divided into four groups (n=10 per group): control, cadmium, betaine and betaine+cadmium (1) saline control group; (2) cadmium group in which cadmium chloride (CdCl2) was given orally at a daily dose of 5 mg/kg body weight for four weeks; (3) betaine group, in which betaine was given to rats at a dose of 250 mg/kg/day, orally via gavage for six weeks; (4) cadmium+betaine group in which betaine was given at a dose of 250 mg/kg/day, orally via gavage for two weeks prior to cadmium administration and concurrently during cadmium administration for four weeks. Cadmium nephrotoxicity was indicated by elevated blood urea nitrogen (BUN) and serum creatinine levels. Kidneys from cadmium-treated rats showed an increase in lipid peroxidation measured as thiobarbituric acid-reactive substances (TBARS) concentration and reductions in total antioxidant status (TAS), reduced glutathione (GSH) content, glutathione peroxidase (GSH-Px) activity, superoxide dismutase concentration (SOD) and catalase activity. Caspase-3 activity, a marker of DNA damage was also elevated in renal tissues of cadmium-treated rats. Pre-treatment of rats with betaine substantially attenuated the increase in BUN and serum creatinine levels. Betaine also inhibited the increase in TBARS concentration and reversed the cadmium-induced depletion in total antioxidant status, GSH, GSH-Px, SOD and catalase concentrations in renal tissues. Renal caspase-3 activity was also reduced with betaine supplementation. These data emphasize the importance of oxidative stress and caspase signaling cascade in cadmium nephrotoxicity and suggest that betaine pretreatment reduces severity of cadmium nephrotoxicity

  15. Pseudomonas aeruginosa KUCD1, a possible candidate for cadmium bioremediation

    PubMed Central

    Sinha, Sangram; Mukherjee, Samir Kumar

    2009-01-01

    A cadmium (8 mM) resistant Pseudomonas aeruginosa strain KUCd1 exhibiting high Cd accumulation under in vitro aerobic condition has been reported. The isolate showed a significant ability to remove more than 75% and 89% of the soluble cadmium during the active growth phase from the growth medium and from Cd-amended industrial wastewater under growth supportive condition. Transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDXS) suggest the presence of Cd in the cells from mid stationary phase. The cell fractionation study revealed membrane and periplasm to be the major accumulating site in this strain. The chemical nature of the accumulated Cd was studied by X-ray powder diffraction analysis. PMID:24031411

  16. Cadmium contamination in cereal-based diets and diet ingredients

    SciTech Connect

    Siitonen, P.H.; Thompson, H.C. Jr. )

    1990-11-01

    Cereal-based diet and/or diet ingredient cadmium levels were determined by graphite furnace AAS. Cadmium contamination was 88.3 and 447 ppb in two cereal-based diets, 44.6 and 48.9 ppb in two purified diets, and ranged from less than 1.1 to 22,900 ppb in the ingredients of one cereal-based diet. The major source of cadmium contamination was attributed to the calcium supplement used for diet formulation. Comparative analyses of two purified diet samples and one cereal-based diet by the National Institute of Standards and Technology (NIST, formerly the National Bureau of Standards) and the National Center for Toxicological Research (NCTR) gave virtually identical results for Cd. A comparative study of Cd levels determined by flame and furnace AAS was also made by the NCTR and the NIST.

  17. Light regulation of cadmium-induced cell death in Arabidopsis

    PubMed Central

    Smith, Sarah J; Wang, Yun; Slabas, Antoni R; Chivasa, Stephen

    2014-01-01

    Cadmium is an environmental pollutant with deleterious effects on both prokaryotic and eukaryotic organisms. In plants, the effects of cadmium toxicity are concentration dependent; lower doses destabilize many physiological processes and inhibit cell growth and multiplication, while higher doses evoke a more severe response that triggers activation of cell death. We recently investigated the effects of light on cadmium toxicity in Arabidopsis using a cell suspension culture system. Although not affecting the inhibitory effects on cell multiplication, we found that light is a powerful regulator of Cd-induced cell death. A very specific proteomic response, which was clearly controlled by light, preceded cell death. Here we discuss the implications of these findings and highlight similarities between the regulation of cell death triggered by Cd and fumonisin B1. We consider how both compounds could be useful tools in dissecting plant cell death signaling. PMID:24398567

  18. Effects of different food doses on cadmium toxicity to Daphnia magna

    SciTech Connect

    Kluettgen, B.; Ratte, H.T. )

    1994-10-01

    Chronic toxicity tests were conducted with Daphnia magma using cadmium concentrations of 0, 0.5, 1, 2, and 5 [mu]g/L Cd with algae doses of 0.8, 4, 8, and 16 [center dot] 10[sup 6] cells/d of Chlorella saccharophila for each. In this way, the authors were able to determine the effects of cadmium on the life-table data of individuals, under different nutritional conditions. The development of juveniles was found to be inhibited by cadmium at low food doses, whereas body length and reproduction were strongly affected at higher food levels. The molting interval of adults and the development rate of embryos proved to be unaffected by cadmium. Cadmium-stressed animals lived longer than did the unstressed controls. The intrinsic rate of natural increase was generally reduced by cadmium, independent of the food dose.

  19. Environmental impact of a cadmium atmospheric pollution at Marseille (South France)

    NASA Astrophysics Data System (ADS)

    Noack, Y.; Lefloch, M.; Robin, D.

    2003-05-01

    In 1999, a cadmium atmospheric pollution had been detected at Marseille, south France. Cadmium was emitted by a wire-drawing factory. The Cd atmospheric concentration reached 5000 ng/m^3, 1000 times over the EEC limit value. After the factory closing, cadmium concentration decreased and reached the EEC limit value (5 ng/m^3) one year after. Soils were also polluted by cadmium (to 60 mg/kg). More than fifty percent of the cadmium in soils is contained in the leachable and bioavailable fractions. Concentration in vegetables had also exceeded the authorized values. A study of cadmium concentration in urines of children and adults living around the factory show a higher average concentration for the population (children and adults) in the contaminated zone, compared to a similar population in a non contaminated zone.

  20. Comparative effects of repeated administration of cadmium chloride during pregnancy and lactation and selenium protection against cadmium toxicity on some organs in immature rats' offsprings.

    PubMed

    Bekheet, Souad H M

    2011-12-01

    This research comprises studies on the transfer of cadmium (CdCl(2)) from the lactating dam to the pup via milk and absorbed in the suckling, showing that cadmium is transferred to the testes, ovary, cerebellum, and thyroid gland during development. The present studies were carried out in order to assess the protective effects of selenium against cadmium toxicity in pregnant rats. On the sixth day of gestation, the females were dosed subcutaneously either with cadmium or with cadmium and selenium in the following doses (mg/kg of body weight): 0, 1 Cd, 1 Cd + 1 Se, 2 Cd, 2 Cd + 2 Se. In groups treated with cadmium, no maternal or embryonic toxicities were observed; however, an increase in testes diameters of seminiferous tubules, a progressive sloughing of germ cells, vacuolization of Sertoli cells, and Leydig cells hyperplasia were noted. The reduction in the ovary size and inhibited folliculogenesis resulted in diminution of the numbers of primordial, growing, and tertiary follicles. The pathological change in the cerebellum, the migration of granular cells from the external germinal layer to the internal granular layer, was strongly retarded. Also, the formation of many microfollicles in the thyroid gland which mimic the changes was seen in thyrotoxicosis. It also appears that selenium used at a low-enough dose could be a very effective protection against cadmium-induced developmental toxicity in the testes, ovary, cerebellum, and thyroid gland but not in the higher dose in the ovary and cerebellum.

  1. Direct effect of cadmium on blood pressure and adrenergic system in the cat

    SciTech Connect

    Revis, N.W.; Bingham, G.

    1984-01-01

    The dose-response effect of cadmium on systolic and diastolic pressure were measured in the cat after injecting a bolus of cadmium intravenously. In animals treated with 100, 125, or 150 ug cadmium/kg BW systolic and diastolic pressure were both significantly increased. These increases were gradual as the dose Cd was increased from 75 to 125 ug. In an attempt to determine the mechanism associated with cadmium-induced hypertension in the cat the effect of this element on the adrenergic system was studied. The effect of ..cap alpha.. and BETA agonists on cadmium-induced increase in blood pressure were determined by the injection of either propranolol or phentolamine at 20 mg/kg BW. The hypertensive effect of 125 ug Cd was abolished by phentolamine but not by propranolol suggesting, that Cd may induce the release of norepinephrine from storage sites. In support of this suggestion we observed in cats treated with 125 ug Cd a significant increase in plasma norepinephrine which was not affected by propranolol or phentolamine injections. However reserpine pretreatment abolished both the increase in plasma norepinephrine and the cadmium-induced hypertensive effect. The data suggest that the associated mechanism of cadmium-induced hypertension may be related to the effect of this element of the release of norepinephrine. Increases in the extracellular levels of this neurotransmitter in turn provokes a rise in blood pressure through its interaction with the receptors of vascular smooth muscle cells. 38 references, 7 figures, 1 table.

  2. Thickness dependence study of inorganic CdTe/CdSe solar cells fabricated from colloidal nanoparticle solutions

    NASA Astrophysics Data System (ADS)

    Ju, Tong; Yang, Lily; Carter, Sue

    2010-05-01

    The thickness dependence of cadmium telluride/cadmium selenide (CdTe/CdSe) heterojunctions is studied in order to maximize the performance of solar cells. The best overall performance of 3.02% efficiency at air mass 1.5 was achieved from a device with 300 nanometers (nm) of sintered CdTe and 100 nm CdSe, using indium tin oxide and evaporated aluminum as the electrodes. In contrast to thin film CdTe solar cells, the power efficiency was strongly dependent on the thickness of the nanoparticle layer, indicating that the device efficiency is limited by charge transport.

  3. Bioavailability of cadmium and its human consequence

    SciTech Connect

    Revis, N.W.

    1984-01-01

    Cadmium intake for the average adult in the USA from water, air and food is approximately 43 ..mu..g/day. This value does not include intake from cigarette smoking or industrial exposure. Intake from these sources would add significantly the total Cd body burden because, Cd absorption via the respiratory track is approximately 10 times the value observed for the gastrointestinal tract. Renal tubular damage is the only human disease in which a dose-response has been established for Cd intake. For renal tubular damage an intake of 200 to 440 ..mu..g/day for 50 years would be necessary to induce this disease in 50% of the exposed population. Thus a safety margin of 10 exists between present intake levels and the amount required to induce renal tubular damage. If animal studies, which show the induction of hypertension following the long-term exposure to drinking water containing 100 ppB Cd, were related to present human intake values of 43 ..mu..g/day the safety margin level would be considerably lower than 10. In contrast, to relate the data from animal studies on cadmium-induced tumors to present human intake values suggest a safety margin greater than 10. 59 references, 4 tables.

  4. In vivo biodistribution and synergistic toxicity of silica nanoparticles and cadmium chloride in mice.

    PubMed

    Guo, Mingchun; Xu, Xiaolong; Yan, Xincheng; Wang, Shasha; Gao, Shang; Zhu, Shanshan

    2013-09-15

    Silica nanoparticles (SiNPs) are now in daily use due to their low intrinsic toxicity. Cadmium is a ubiquitous environmental pollutant. In spite of real risk of humans' co-exposure to SiNPs and cadmium, their synergistic toxicity is still unclear. Here, we report the synergistic effects of SiNPs and CdCl₂ on their biodistribution and subacute toxicity in mice. The biodistributions, histopathological changes, serum biochemical parameters and oxidative stress responses were determined after intraperitoneal injection of SiNPs and/or CdCl₂ to mice. SiNPs and CdCl₂ have a positive synergistic toxicity in mice. Although SiNPs were low toxic to mice, co-exposure of SiNPs and CdCl₂ significantly enhanced CdCl₂-induced oxidative damage in the liver as indicated by the severe liver dysfunction and histopathological abnormalities. Co-exposure to SiNPs and CdCl₂ markedly increased the cadmium accumulation in the liver, which induced significant hepatic oxidative stress. In vitro binding assays indicated that serum albumin and Cd(2+) mutually enhanced the binding of each other to SiNPs via the interaction of serum albumin and Cd(2+). The uptake of serum albumin- and Cd(2+)-bound SiNPs by the macrophages significantly increased cadmium accumulation in mice. These results demonstrate that serum albumins play an important role in the positive synergistic toxicity of SiNPs and CdCl₂.

  5. DGT estimates cadmium accumulation in wheat and potato from phosphate fertilizer applications.

    PubMed

    Pérez, Angela L; Anderson, Kim A

    2009-09-01

    Cadmium is a common impurity in phosphatic fertilizers and may contribute to soil Cd accumulation. Changes in total and bioavailable Cd burdens to agricultural soils and the potential for plant Cd accumulation resulting from fertilizer input was investigated. Three year field studies were conducted using three dose levels of cadmium-rich, commercial, phosphate fertilizers applied at four agricultural sites. Labile Cd concentrations, measured using the passive sampling device Diffusive Gradients in Thin Films (Cd(DGT)), increased with increasing fertilizer application rates. Cd also accumulated in the edible portion of wheat and potato crops grown at the sites, and showed strong positive dose response with fertilizer treatment. Regression models were calculated for each site, year, and for individual crops. Model comparisons indicated that soil physical and chemical parameters in addition to soil Cd fractions, were important determinants of Cd(DGT). Significant factors contributing to Cd(DGT) concentrations were Cd from fertilizer input (Cd(fertilizer)), pH, cation exchange capacity (CEC), and total recoverable Cd (Cd(total)). Important factors used to determine Cd concentrations in wheat grain (Cd(wheat)) and in potato (Cd(potato)) were as follows: Cd(wheat):Cd(fertilizer), and Cd(DGT); and Cd(potato):Cd(fertilizer), Cd(DGT), % O.M. The effective concentration, C(E), calculated from DGT did not correlate well with Cd(wheat) or with Cd(potato). Direct measurements of Cd(DGT) correlated better with Cd found in edible plant tissue. The modeling approach presented in this study helps to estimate Cd accumulation in plant tissue over multiple years and in distinct agricultural soil systems.

  6. Past and future cadmium emissions from municipal solid-waste incinerators in Japan for the assessment of cadmium control policy.

    PubMed

    Ono, Kyoko

    2013-11-15

    Cadmium (Cd) is a harmful pollutant emitted from municipal solid-waste incinerators (MSWIs). Cd stack emissions from MSWIs have been estimated between 1970 and 2030 in Japan. The aims of this study are to quantify emitted Cd by category and to analyze Cd control policies to reduce emissions. Emissions were estimated using a dynamic substance flow analysis (SFA) that took into account representative waste treatment flows and historical changes in emission factors. This work revealed that the emissions peaked in 1973 (11.1t) and were ten times those in 2010 (1.2 t). Emission from MSWIs was two-thirds of that from non-ferrous smelting in 2010. The main Cd emission source was pigment use in the 1970s, but after 2000 it had shifted to nickel-cadmium (Ni-Cd) batteries. Future emissions were estimated for 2030. Compared to the business-as-usual scenario, an intensive collection of used Ni-Cd batteries and a ban on any future use of Ni-Cd batteries will reduce emissions by 0.09 and 0.3 1t, respectively, in 2030. This approach enables us to identify the major Cd emission source from MSWIs, and to prioritize the possible Cd control policies.

  7. Infrared birefringence spectra for cadmium sulfide and cadmium selenide.

    PubMed

    Chenault, D B; Chipman, R A

    1993-08-01

    Measurements of the birefringence spectra for cadmium sulfide and cadmium selenide from 2.5 to 16.5µm obtained with a rotating sample spectropolarimeter are presented. Because of the similarity in the birefringence spectra for cadmium sulfide and cadmium selenide, a highly achromatic IR retarder can be constructed from a combination of these materials. The ordinary and extraordinary refractive indices for cadmium sulfide are estimated in the region from 10.6 to 15 µm and for cadmium selenide from 10.6 to 16.5 µm by combining these birefringence data with an extrapolation of previous dispersion relations.

  8. Cadmium and lung cancer mortality accounting for simultaneous arsenic exposure

    PubMed Central

    Park, Robert M; Stayner, Leslie T; Petersen, Martin R; Finley-Couch, Melissa; Hornung, Richard; Rice, Carol

    2015-01-01

    Objectives Prior investigations identified an association between airborne cadmium and lung cancer but questions remain regarding confounding by arsenic, a well-established lung carcinogen. Methods A cadmium smelter population exhibiting excess lung cancer was re-analysed using a retrospective exposure assessment for arsenic (As), updated mortality (1940–2002), a revised cadmium (Cd) exposure matrix and improved work history information. Results Cumulative exposure metrics for both cadmium and arsenic were strongly associated making estimation of their independent effects difficult. Standardised mortality ratios (SMRs) were modelled with Poisson regression with the contribution of arsenic to lung cancer risk constrained by exposure–response estimates previously reported. The results demonstrate (1) a statistically significant effect of Cd independent of As (SMR=3.2 for 10 mg-year/m3 Cd, p=0.012), (2) a substantial healthy worker effect for lung cancer (for unexposed workers, SMR=0.69) and (3) a large deficit in lung cancer mortality among Hispanic workers (SMR=0.27, p=0.009), known to have low lung cancer rates. A supralinear dose-rate effect was observed (contribution to risk with increasing exposure intensity has declining positive slope). Lung cancer mortality was somewhat better predicted using a cadmium burden metric with a half-life of about 20–25 years. Conclusions These findings support an independent effect for cadmium in risk of lung cancer mortality. 1/1000 excess lifetime risk of lung cancer death is predicted from an airborne exposure of about 2.4 μg/m3 Cd. PMID:22271639

  9. Paxillus involutus-Facilitated Cd2+ Influx through Plasma Membrane Ca2+-Permeable Channels Is Stimulated by H2O2 and H+-ATPase in Ectomycorrhizal Populus × canescens under Cadmium Stress

    PubMed Central

    Zhang, Yuhong; Sa, Gang; Zhang, Yinan; Zhu, Zhimei; Deng, Shurong; Sun, Jian; Li, Nianfei; Li, Jing; Yao, Jun; Zhao, Nan; Zhao, Rui; Ma, Xujun; Polle, Andrea; Chen, Shaoliang

    2017-01-01

    Using a Non-invasive Micro-test Technique, flux profiles of Cd2+, Ca2+, and H+ were investigated in axenically grown cultures of two strains of Paxillus involutus (MAJ and NAU), ectomycorrhizae formed by these fungi with the woody Cd2+-hyperaccumulator, Populus × canescens, and non-mycorrhizal (NM) roots. The influx of Cd2+ increased in fungal mycelia, NM and ectomycorrhizal (EM) roots upon a 40-min shock, after short-term (ST, 24 h), or long-term (LT, 7 days) exposure to a hydroponic environment of 50 μM CdCl2. Cd2+ treatments (shock, ST, and LT) decreased Ca2+ influx in NM and EM roots but led to an enhanced influx of Ca2+ in axenically grown EM cultures of the two P. involutus isolates. The susceptibility of Cd2+ flux to typical Ca2+ channel blockers (LaCl3, GdCl3, verapamil, and TEA) in fungal mycelia and poplar roots indicated that the Cd2+ entry occurred mainly through Ca2+-permeable channels in the plasma membrane (PM). Cd2+ treatment resulted in H2O2 production. H2O2 exposure accelerated the entry of Cd2+ and Ca2+ in NM and EM roots. Cd2+ further stimulated H+ pumping activity benefiting NM and EM roots to maintain an acidic environment, which favored the entry of Cd2+ across the PM. A scavenger of reactive oxygen species, DMTU, and an inhibitor of PM H+-ATPase, orthovanadate, decreased Ca2+ and Cd2+ influx in NM and EM roots, suggesting that the entry of Cd2+ through Ca2+-permeable channels is stimulated by H2O2 and H+ pumps. Compared to NM roots, EM roots exhibited higher Cd2+-fluxes under shock, ST, and LT Cd2+ treatments. We conclude that ectomycorrhizal P. × canescens roots retained a pronounced H2O2 production and a high H+-pumping activity, which activated PM Ca2+ channels and thus facilitated a high influx of Cd2+ under Cd2+ stress. PMID:28111579

  10. Significance of cadmium levels in blood and urine during long-term exposure of rats to cadmium

    SciTech Connect

    Bernard, A.; Goret, A.; Buchet, J.P.; Roels, H.; Lauwerys, R.

    1980-01-01

    Cadmium concentrations in blood, urine, kidney cortex, and liver were followed in female rats injected ip with 1 mg/kg Cd 5 times a week for 3 months or receiving CdCl/sub 2/ in drinking water at 2 and 20 ppM Cd for 11 months and 200 ppM Cd for 8 months. Control rats were given deionized water or injected with physiological saline. At low exposures (0, 2, and 20 ppM Cd po) the rate of Cd accumulation in liver was lower than that in kidney cortex, whereas at higher exposures it equaled (200 ppM Cd po) or even exceeded (1 mg/kg Cd ip) that in kidney cortex. In groups receiving 2, 20, and 200 ppM Cd, the Cd concentration in blood increased to a plateau value, which was reached after about 3 months of treatment and was proportional to the Cd concentration in drinking water; this suggests that, at equilibrium, the blood Cd level mainly reflects current exposure. In rats injected with 1 mg/kg Cd ip no plateau level of Cd in blood was reached, although a tendency to level off seemed to occur after 2.5 mo. The Cd concentration in urine fluctuated more than that in blood. However, at all doses and before renal damage occurred, the amount of Cd excreted in urine tended to increase with duration of treatment. The significant correlation between the Cd level in renal cortex and that in urine confirms that the latter is mainly a reflection of the body burden. When renal dysfunction occurs, excretion of Cd in urine increases sharply.The results of these experiments confirm previous conclusions derived from clinical investigations, that in the absence of Cd-induced renal damage, Cd in blood mainly reflects recent exposure whereas Cd in urine is a satisfactory indicator of the amount of Cd stored in the kidney.

  11. Chronic cadmium exposure stimulates SDF-1 expression in an ERα dependent manner.

    PubMed

    Ponce, Esmeralda; Aquino, Natalie B; Louie, Maggie C

    2013-01-01

    Cadmium is an omnipotent environmental contaminant associated with the development of breast cancer. Studies suggest that cadmium functions as an endocrine disruptor, mimicking the actions of estrogen in breast cancer cells and activating the receptor to promote cell growth. Although acute cadmium exposure is known to promote estrogen receptor-mediated gene expression associated with growth, the consequence of chronic cadmium exposure is unclear. Since heavy metals are known to bioaccumulate, it is necessary to understand the effects of prolonged cadmium exposure. This study aims to investigate the effects of chronic cadmium exposure on breast cancer progression. A MCF7 breast cancer cell line chronically exposed to 10(-7) M CdCl2 serves as our model system. Data suggest that prolonged cadmium exposures result in the development of more aggressive cancer phenotypes - increased cell growth, migration and invasion. The results from this study show for the first time that chronic cadmium exposure stimulates the expression of SDF-1 by altering the molecular interactions between ERα, c-jun and c-fos. This study provides a mechanistic link between chronic cadmium exposure and ERα and demonstrates that prolonged, low-level cadmium exposure contributes to breast cancer progression.

  12. Nicotine-Cadmium Interaction Alters Exploratory Motor Function and Increased Anxiety in Adult Male Mice

    PubMed Central

    Chris Ajonijebu, Duyilemi; Adeyemi Adeniyi, Philip; Oloruntoba Adekeye, Adeshina; Peter Olatunji, Babawale; Olakunle Ishola, Azeez; Michael Ogundele, Olalekan

    2014-01-01

    In this study we evaluated the time dependence in cadmium-nicotine interaction and its effect on motor function, anxiety linked behavioural changes, serum electrolytes, and weight after acute and chronic treatment in adult male mice. Animals were separated randomly into four groups of n = 6 animals each. Treatment was done with nicotine, cadmium, or nicotine-cadmium for 21 days. A fourth group received normal saline for the same duration (control). Average weight was determined at 7-day interval for the acute (D1-D7) and chronic (D7-D21) treatment phases. Similarly, the behavioural tests for exploratory motor function (open field test) and anxiety were evaluated. Serum electrolytes were measured after the chronic phase. Nicotine, cadmium, and nicotine-cadmium treatments caused no significant change in body weight after the acute phase while cadmium-nicotine and cadmium caused a decline in weight after the chronic phase. This suggests the role of cadmium in the weight loss observed in tobacco smoke users. Both nicotine and cadmium raised serum Ca2+ concentration and had no significant effect on K+ ion when compared with the control. In addition, nicotine-cadmium treatment increased bioaccumulation of Cd2+ in the serum which corresponded to a decrease in body weight, motor function, and an increase in anxiety. PMID:26317007

  13. Soil pH effect on phosphate induced cadmium precipitation in Arable soil.

    PubMed

    Hong, Chang Oh; Owens, Vance N; Kim, Yong Gyun; Lee, Sang Mong; Park, Hyean Cheal; Kim, Keun Ki; Son, Hong Joo; Suh, Jeong Min; Kim, Pil Joo

    2014-07-01

    The objective of this study was to determine soil pH conditions that allow cadmium (Cd) to precipitate as Cd minerals in phosphate (P) amended soil. Cadmium immobilization could be attributed primarily to Cd adsorption due to increase in pH and negative charge. Soil pH might not affect Cd precipitation as Cd3(PO4)2 by direct reaction of Cd and P in the studied soil, even when soil pH increased up to 9.0. However, Cd might precipitate as CdCO3 with increasing pH up to 9.0 in P untreated soil and up to 8.0 in P treated soil depending on CO2 level.

  14. Optical properties of multicomponent cadmium-silver nanocluster composites formed in silica by sequential ion implantation

    SciTech Connect

    Zuhr, R.A.; Magruder, R.H. III; Anderson, T.S.

    1996-11-01

    Formation and optical properties of nanometer dimension metal colloid composites formed by sequential implantation of Cd then Ag and by single element implantations of Cd and Ag in silica were characterized by TEM and optical spectroscopy. A nominal dose of 6x10{sup 16} ions/cm{sup 2} as determined by current integration was used for both ion species. Doses used for the sequential implantations were a 1 to 1 ratio of Cd to Ag. Sequential implantations of Cd and Ag led to formation of both multi-component metal nanoclusters and elemental nanoclusters. Electron diffraction indicated that the polycrystalline particles of Ag{sub 5}Cd{sub 8} and elemental Ag were formed. The optical response was consistent with results expected from effective medium theory.

  15. Citrate-stabilized Q-CdSe seed-mediated synthesis of silver nanoparticles: The role of citrate moieties anchored to the Q-CdSe surface

    NASA Astrophysics Data System (ADS)

    Ingole, Pravin P.; Bhat, Mohsin A.

    2016-03-01

    Here, we try to explore a new dimension/role for citrate molecules in the bound state, i.e. anchored to the surface of cadmium selenide quantum dots (Q-CdSe), in the synthesis of metal nanoparticles (MNPs). Being labile, the citrate molecule is considered a good candidate for the stabilization of semiconductor quantum dots (QDs) such as Q-CdSe that can be used for further functionalization/modification of the surface properties of the QDs. In its free/ionic form (i.e. not bound to the surface), it is well known for its role as a reducing as well as a capping agent in the synthesis of silver and gold MNPs. A simple strategy for the preparation of silver MNPs following the chemical reduction of silver ions that is mediated by citrate-stabilized Q-CdSe seeds without addition of an external reducing agent is presented. The citrate moieties anchored to the surface of Q-CdSe are found to play an important role in the chemical reduction of silver ions. The obtained product was analysed by spectroscopic, microscopic and structural characterization techniques such as surface plasmon resonance (SPR), transmission electron microscopy (TEM) and cyclic voltammetry. The characteristic redox behaviour observed in cyclic voltammograms (CVs) also supports the formation of Ag MNPs in the samples. Further, the impact of the reaction solution pH on the feasibility of silver ion reduction by Q-CdSe seeds resulting into the formation of Ag MNPs is also briefly discussed.

  16. Cadmium and dimethylnitrosamine as synergists in carcinogenesis

    SciTech Connect

    Wade, G.G. Jr.

    1986-01-01

    A two part study was conducted with male Wistar rats to investigate possible synergism in carcinogenesis between Cd and dimethylnitrosamine (DMN). In Series I, rats received an intraperitoneal dose of DMN followed at 4 hours and at 4 days by intramuscular injections of CdCl/sub 2/. Series II rats received a series of intramuscular CdCl/sub 2/ injections over 13 days followed by an intraperitoneal DMN injection 24 hours later. Untreated and single agent controls were incorporated. One year after DMN exposure, both Series show a significant (p < 0.025) synergistic increase in the incidence of renal neoplasia and an additive increase in the incidence of focal atypical hyperplasia (FAH) of renal tubules. Likewise, there was a synergistic increase in the number of altered foci/areas in livers of Series I animals. In addition, Series I rats with combined treatment had a significant increase in tumor incidence at sites other than kidney. Pretreatment with DMN was more synergistic in toxicity than pretreatment with Cd. Series II animals also showed an apparent shift in renal tumor type from mesenchymal and tubular neoplasms to tubular epithelial neoplasms alone. Theories on the origin(s) of malignant transformation are reviewed as is the biologic important of cadmium in the environment and possible mechanisms of synergistic action. This thesis supports (1) the finding of synergism in the occurrence of renal cancer in man associated with cadmium exposure and cigarette smoking, (2) the importance of synergisms in carcinogenesis, (3) the importance of such interaction in the determination of threshold doses, and (4) the role that indirect mechanisms play in carcinogenic activity of cadmium and other heavy metals.

  17. Photovoltaic Properties of CdSe/CdS and CdS/CdSe Core-Shell Particles Synthesized by Use of Uninterrupted Precipitation Procedures

    NASA Astrophysics Data System (ADS)

    Selene Coria-Monroy, C.; Sotelo-Lerma, M.; Martínez-Alonso, Claudia; Moreno-Romero, Paola M.; Rodríguez-Castañeda, Carlos A.; Corona-Corona, Israel; Hu, Hailin

    2015-10-01

    Cadmium Selenide (CdSe) and cadmium sulfide (CdS) are good electron acceptors for hybrid solar cells. CdSe and CdS nanoparticles can be prepared at low temperatures (60-80°C) from alkaline aqueous solutions of a cadmium salt, sodium citrate, and thiourea, as sulfur source, or sodium selenosulfate, as selenium source. Under the same experimental conditions, the reaction kinetics for CdS were faster than for CdSe. Formation of CdSe/CdS core-shell particles (type I: CdSe as core and CdS as shell) could be achieved by use of an uninterrupted one-step process by setting high and low solution temperatures for the core and shell compounds, respectively. The yield of the CdSe product was higher at a pH 8.5-9.5 whereas that of the CdS product was higher at higher pH (10-11). Therefore, formation of the "inverse" CdS/CdSe structure (type II: CdS as core and CdSe as shell) was possible in a one-step solution process by choosing a high solution pH for the core and a lower pH for the shell. Photoluminescence spectra and electron micrographs confirmed formation of the two types of core-shell particle. The photovoltaic performance of heterojunctions prepared with core-shell particles and poly(3-hexylthiophene) (P3HT), also suggested formation of core-shell particles. Both the photovoltage and photocurrent density of hybrid solar cells depended on the shell compound and not on the core. It was shown that the interface of the heterojunctions plays is important in solar cell applications, and its modification could be realized by incorporating different shell compounds on core particles.

  18. Distribution of blood lead, blood cadmium, urinary cadmium, and urinary arsenic levels in employees of a copper smelter

    SciTech Connect

    Lilis, R.; Valciukas, J.A.; Weber, J.P.; Fischbein, A.; Nicholson, W.J.; Campbell, C.; Malkin, J.; Selikoff, I.J.

    1984-02-01

    A cross-sectional medical examination of a copper smelter work force included determination of blood lead (Pb-B), zinc protoporphyrin (ZPP), blood cadmium (Cd-B), urinary cadmium (Cd-U), and urinary arsenic (As-U), since it was known that such metal impurities were present in the copper concentrate. A total of 776 copper smelter employees (680 active and 96 retirees and ex-employees) were examined. Another 144 men, never employed in the smelter, but who had worked in copper mines (and sometimes in gold mines) were also examined. Mean Pb-B, ZPP, Cd-B, and As-U were significantly higher in active copper smelter employees than in retirees or miners, indicating exposure and absorption in the copper smelter. Significant correlations between Pb-B and Cd-B, and Cd-U and As-U were present, confirming the common source of absorption. Although there was evidence for an increased lead absorption, this was very moderate, with practically no Pb-B levels in excess of 60 ..mu..g/dl. A marked effect of smoking on blood cadmium levels was present; nevertheless, for all smoking categories Cd-B levels were significantly higher in active employees, indicating the independent contribution of exposure to cadmium in the smelter. Cd-U did not exceed 10 ..mu..g/g creatinine, the generally accepted critical level for the kidney, but was higher than 2 ..mu..g/g cretinine, a level very rarely exceeded in the general population, in a sizable proportion of those examined. The highest Cd-U levels were found in retired copper smelter employees; age might have been a contributing factor, besides a longer duration of exposure in the smelter.

  19. Effective Phytoextraction of Cadmium (Cd) with Increasing Concentration of Total Phenolics and Free Proline in Cannabis sativa (L) Plant Under Various Treatments of Fertilizers, Plant Growth Regulators and Sodium Salt.

    PubMed

    Ahmad, Ayaz; Hadi, Fazal; Ali, Nasir

    2015-01-01

    The comparative effect of fertilizers (NPK), plant growth regulators (GA3, IAA, Zeatin) and sodium chloride (NaCl) on Cd phytoaccumulation, proline and phenolics production in Cannabis sativa was evaluated. Proline and phenolices were correlated with Cd contents in plant. Cd significantly reduced the plant growth. Fertilizers application (in combination) most significantly increased the growth (19 cm root and 47 cm shoot) on Cd contaminated soil. All treatments increased the Cd contents in plant tissues. This increase was highly significant in fertilizers treated plants (1101, 121 and 544 ppm in roots, stem and leaves respectively). Significantly positive correlation was found between Cd concentration and dry biomass of root (R2=0.7511) and leaves (R2=0.5524). All treatments significantly increased the proline and total phenolics and maximum was recorded in NaCl treated plants followed by fertilizers. Proline was higher in roots while phenolics in leaves. The correlation between proline and phenolics was positive in leaf (R2=0.8439) and root (R2=0.5191). Proline and phenolics showed positive correlation with Cd concentration in plant. Conclusively, fertilizers in combination seem to be the better option for Cd phytoextraction. Further investigation is suggested to study the role of phenolics and proline in Cd phytoextraction.

  20. Cd-tolerant Suillus luteus: a fungal insurance for pines exposed to Cd.

    PubMed

    Krznaric, Erik; Verbruggen, Nathalie; Wevers, Jan H L; Carleer, Robert; Vangronsveld, Jaco; Colpaert, Jan V

    2009-05-01

    Soil metal pollution can trigger evolutionary adaptation in soil-borne organisms. An in vitro screening test showed cadmium adaptation in populations of Suillus luteus (L.: Fr.) Roussel, an ectomycorrhizal fungus of pine trees. Cadmium stress was subsequently investigated in Scots pine (Pinus sylvestris L.) seedlings inoculated with a Cd-tolerant S. luteus, isolated from a heavy metal contaminated site, and compared to plants inoculated with a Cd-sensitive isolate from a non-polluted area. A dose-response experiment with mycorrhizal pines showed better plant protection by a Cd-adapted fungus: more fungal biomass and a higher nutrient uptake at high Cd exposure. In addition, less Cd was transferred to aboveground plant parts. Because of the key role of the ectomycorrhizal symbiosis for tree fitness, the evolution of Cd tolerance in an ectomycorrhizal partner such as S. luteus can be of major importance for the establishment of pine forests on Cd-contaminated soils.

  1. Stabilizing cadmium into aluminate and ferrite structures: Effectiveness and leaching behavior.

    PubMed

    Su, Minhua; Shih, Kaimin; Kong, Lingjun

    2017-02-01

    The inappropriate disposal of sludge, particularly for those enriched in heavy metals, is highly hazardous to the environment. Thermally converting sludge into useful products is a highly promising technique as heavy metals are immobilized and organic substances are mineralized. This work investigated the feasibility of stabilizing simulated cadmium-laden sludge by sintering with Al-and Fe-rich precursors. To simulate the process, cadmium oxide was alternatively mixed and sintered with γ-Al2O3 and α-Fe2O3. Cadmium was crystallographically incorporated into aluminate (CdAl4O7) monoclinic structure and ferrite (CdFe2O4) spinel, dependent on the type of precursor used. The CdFe2O4 formation was initialed at about 150-300 °C lower than that of CdAl4O7. With Rietveld refinement analysis of the collated XRD data, the weight percentages of crystalline phases in the fired samples were quantified. To evaluate the cadmium incorporation efficiency, a transformation ratio (TR) index was devised. The TR values revealed that, to effectively incorporate cadmium, 950 °C was favored by γ-Al2O3 and 850 °C was for α-Fe2O3 within a 3-h sintering treatment. Constant pH leaching test (CPLT) was used to assess the metal stabilization effects, revealing a remarkable reduction of cadmium by transformation into CdAl4O7 and CdFe2O4. Both CdAl4O7 and CdFe2O4 were incongruently dissolved in an acid solution. The overall finding indicated a potentially feasible technology in cadmium-laden sludge stabilization.

  2. Cadmium zinc sulfide by solution growth

    DOEpatents

    Chen, Wen S.

    1992-05-12

    A process for depositing thin layers of a II-VI compound cadmium zinc sulfide (CdZnS) by an aqueous solution growth technique with quality suitable for high efficiency photovoltaic or other devices which can benefit from the band edge shift resulting from the inclusion of Zn in the sulfide. A first solution comprising CdCl.sub.2 2.5H.sub.2 O, NH.sub.4 Cl, NH.sub.4 OH and ZnCl.sub.2, and a second solution comprising thiourea ((NH.sub.2).sub.2 CS) are combined and placed in a deposition cell, along with a substrate to form a thin i.e. 10 nm film of CdZnS on the substrate. This process can be sequentially repeated with to achieve deposition of independent multiple layers having different Zn concentrations.

  3. Cadmium Nanowire Formation Induced by Ion Irradiation

    SciTech Connect

    Jiang, Weilin; Weber, William J.; Wang, Chong M.; Young, James S.; Boatner, Lynn A.; Lian, Jie; Wang, Lumin; Ewing, Rodney C.

    2005-07-04

    One-dimensional nanostructures, such as nanowires, of semiconductors and metals are of great technological interest due to their potential for many advanced technology applications. Utilization of these materials versus their bulk counterparts will not only allow for device miniaturisation, but also may improve device performance or create new functions. Here we report a novel method for the synthesis of crystalline Cd-nanowires without involving either templates or a “seeded” structure. Ion irradiation at low temperatures (≤ 295 K) has been used to induce material decomposition and phase segregation in a cadmium niobate pyrochlore (Cd2Nb2O7) wafer. During the formation and rupture of the gas-filled blisters in the material, soft metallic Cd is extruded/extracted as nanowires through pores in the exfoliated layer. The entire process may be readily controlled by changing the ion irradiation conditions (e.g., ion species, dose and energy) with minimal thermal constraints.

  4. Investigating the distribution of dissolved copper, zinc, silver and cadmium in the Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Janssen, D. J.; Cullen, J. T.

    2012-12-01

    A stated goal of the GEOTRACES program is to better understand the large-scale distribution of trace metals in the marine environment. A characteristic feature of the soft Lewis acid metals like copper (Cu), zinc (Zn), silver (Ag) and cadmium (Cd) is their correlation with the major algal nutrients. These correlations imply that the proximate control on the distribution of these metals is microbial uptake at the ocean surface, sinking associated with particulate organic matter and subsequent remineralization in the ocean interior. Combined with sedimentary records of past metal concentrations such correlations can provide much needed information on water mass circulation and nutrient cycling in the paleo-ocean. Today, as trace nutrients and/or toxins these metals help shape microbial community composition and influence productivity. Here we present depth profiles through the low dissolved oxygen waters of the north Pacific which show decoupling of trace metal-macronutrient relationships driven by depletion anomalies of trace metal concentrations in the broad, low oxygen layer. Similar anomalies have been previously reported in permanently anoxic layers (e.g. fjords) or in waters in contact with suboxic sediments and attributed to sulfidic removal of soft trace metals. The observed trace metal behavior and trace metal-macronutrient relationships in the oxygen minimum layer in the northeastern Pacific is consistent with the possibility of sulfidic scavenging of soft metals and the formation of insoluble metal sulfides in the water column. Implications of this influence on the basin scale distribution of soft metals like Cu, Zn, Ag, Cd through scavenging in the spreading low oxygen layer in the northeastern Pacific are discussed.

  5. Cadmium in food chain and health effects in sensitive population groups.

    PubMed

    Oskarsson, Agneta; Widell, Anna; Olsson, Ing-Marie; Grawé, Kierstin Petersson

    2004-10-01

    Even at the low exposure level of cadmium found in this study population living on farms in southern Sweden, there was an indication of effect on biochemical markers of renal function. Women had higher blood cadmium (BCd) and urinary cadmium (UCd) than men, which can be explained by higher absorption of Cd due to low iron status. In the present study, Cd in pig kidneys could not be used to predict human BCd or UCd even though cereals are a substantial part of both the human and the pig diet. The contribution of Cd from locally produced food to the total dietary intake in humans was relatively low and varied and the intake of Cd did not correlate with BCd or UCd. In contrast, Cd levels in pig kidney were significantly related to Cd levels in feed. However, there was no relationship between the locally produced cereals, constituting the main part of the feed, and Cd in pig kidneys. In pig feed, other non-locally produced ingredients contributed to a large part of the Cd in feed. The Cd in non-locally produced feed ingredients reaches the local circulation via excretion in faeces and application of manure to arable soils and will lead to increased levels in the crops. As indicated by experimental data from animals, neurochemical and neurobehavioral effects during development need to be further explored as sensitive endpoints for cadmium toxicity.

  6. CdS/CdTe thin-film devices using a Cd2SnO4 transparent conducting oxide

    NASA Astrophysics Data System (ADS)

    Wu, X.; Sheldon, P.; Coutts, T. J.; Rose, D. H.; Mulligan, W. P.; Moutinho, H. R.

    1997-02-01

    Transparent conducting oxide films of cadmium stannate (Cd2SnO4) have several significant advantages over conventional transparent conducting oxides. They are more conductive, more transparent, have lower surface roughness, are patternable, and are exceptionally stable. Cd2SnO4-based CdS/CdTe polycrystalline thin-film solar cells with efficiencies of 13.7% have been fabricated for the first time. Preliminary cell results have demonstrated that device performance can be enhanced by replacing the SnO2 layer with a Cd2SnO4 transparent conductive oxide.

  7. Studies on structural & optical properties of CdS0.2Se0.8: Ag nanocomposite thin film for photosensor application

    NASA Astrophysics Data System (ADS)

    Chaudhari, J. B.; Patil, R. S.; Patil, I. J.; Jagtap, P. P.; Sharma, Ramphal

    2012-06-01

    Silver doped CdS0.2Se0.8 thin films of different concentrations were grown by simple and economical chemical bath deposition technique and later on characterized for optoelectronic and physicochemical properties. The X-ray diffraction (XRD) patterns of undoped and doped sample indicates polycrystalline nature with hexagonal structure. Scanning electron microscopy (SEM) micrograph showed uniform morphology with cabbage type structure for undoped film and leaf-like structure for doped films over the entire glass substrate. Room temperature absorbance for 1 wt% doping concentration of silver showed an excitonic peak which confirms the size quantization of the particle. I-V characteristic for undoped and doped film shows ohmic and Schottky junction behavior.

  8. Absorption and distribution of cadmium in mice fed diets containing either inorganic or oyster-incorporated cadmium

    SciTech Connect

    Sullivan, M.F.; Hardy, J.T.; Miller, B.M.; Buschbom, R.L.; Siewicki, T.C.

    1984-02-01

    To determine the absorption, organ distribution, and retention of organically bound cadmium (Cd) and the effects of dietary zinc (Zn) on Cd metabolism, groups of mice were fed five different diets. The organic Cd used in the diets was in the form of lyophilized oyster (Crassostrea virginica) that had accumulated radiolabeled 109Cd through a plankton food chain. The mice were fed either a standard basal mouse diet (AIN-76) or diets containing five or eight times the Zn concentration of the basal diet. The source of Zn was either oyster tissue or ZnCO3. The concentration of organic and inorganic Cd provided a dose of approximately 0.4 mg/kg. Diets prepared from oyster tissue probably contained all of the Cd and 85% of the Zn in organic form. Diets prepared with inorganic metals contained about the same Cd and Zn concentrations as the diets prepared with oyster. There was very little difference between the retention of Cd by mice that ingested organic (oyster bound) Cd and those fed inorganic Cd (CdCl2). However, when the Cd retained in the intestine was excluded, retention of organic Cd was significantly greater than that of inorganic Cd. The organ distribution of Cd differed significantly according to the chemical form of Cd fed (organic or inorganic) and the Zn level in the diet. The kidneys of mice fed organically bound Cd retained a higher percentage of the metal than the kidneys of those fed inorganic Cd. On the other hand, the livers of animals fed a low-Zn diet retained a higher percentage of the Cd than the livers of those fed a high-Zn diet, regardless of the dietary source of Cd.

  9. Health, safety and environmental issues relating to cadmium usage in photovoltaic energy systems

    SciTech Connect

    Moskowitz, P.D.; Fthenakis, V.M. ); Zweibel, K. )

    1990-01-01

    This paper discusses the current technology base and hazards associated with two promising thin-film photovoltaic cells that contain cadmium compounds--cadmium telluride (CdTe) and copper indium deselenide (CuInSe{sub 2}). More specifically, this paper summarized the toxicological information on cadmium (Cd) compounds;evaluates potential health, safety and environmental hazards associated with cadmium usage in the photovoltaics industry; describes regulatory requirements associated with the use, handling and disposal of cadmium compounds; and lists management options to permit the safe and continued use of these materials. Handling of cadmium in photovoltaic production can present hazards to health, safety and the environment. Prior recognition of these hazards can allow device manufacturers and regulators to implement appropriate and readily available hazard management strategies. Hazards associated with product use (i.e., array fires) and disposal remain controversial and partially unresolved. The most likely effects that could be expected would be those associated with chronic low-level exposures to cadmium wastes. Because of the general immobility of the cadmium present in these devices and availability of environmental and biomonitoring protocols, chronic hazards can be monitored, and remediated if necessary. 26 refs., 5 figs., 2 tabs.

  10. Cadmium-binding proteins in midgut gland of freshwater crayfish Procambarus clarkii

    SciTech Connect

    Del Ramo, J.; Pastor, A.; Torreblanca, A.; Medina, J.; Diza-Mayans, J.

    1989-02-01

    Metallothioneins, metal binding proteins, were originally isolated and characterized by Margoshes and Vallee. These proteins have a high affinity for various heavy metals, particularly cadmium and mercury and have extensively been studied in mammals. Metal binding proteins have been observed in a variety of marine invertebrates; however, there is very little information available on metal binding proteins in freshwater invertebrates, and particularly in freshwater crustaceans. Cadmium is an ubiquitous non essential element which possesses high toxicity to aquatic organisms. Cadmium binding proteins observed in invertebrates have similar characteristics to mammalian metallothioneins. In 1978, the American red crayfish appeared in Albufera Lake and the surrounding rice fields (Valencia, Spain). Albufera Lake and the surrounding rice fields waters are subjected to very heavy loads of sewage and toxic industrial residues (including heavy metals) from the many urban and wastewaters in this area. In previous reports the authors studied the toxicity and accumulation of cadmium on Procambarus clarkii of Albufera Lake. This crayfish shows a high resistance to cadmium and a great accumulation rate of this metal in several tissues, including midgut gland. Since Procambarus clarkii shows a high resistance to cadmium, the presence of cadmium binding proteins (Cd-BP) in midgut gland of these crayfish would be expected. This report describes results on the characterization of Cd-BPs obtained from cadmium exposed crayfish Procambarus clarkii, demonstrating their presence in this freshwater crayfish.

  11. Protective effect of Irvingia gabonensis stem bark extract on cadmium-induced nephrotoxicity in rats.

    PubMed

    Ojo, Oluwafemi Adeleke; Ajiboye, Basiru Olaitan; Oyinloye, Babatunji Emmanuel; Ojo, Adebola Busola; Olarewaju, Olaide Ibiwumi

    2014-12-01

    Cadmium has been considered a risk factor for humans as it accumulates in body tissues, such as the liver, lungs, kidneys, bones, and reproductive organs. The aim of the present study was to evaluate the effect of Irvingia gabonensis (IG) against cadmium (Cd)-induced nephrotoxicity. The study was performed on twenty (20) male rats divided into four groups: control group, cadmium group (4 mg/kg/day, intraperitoneally), cadmium + extract (200 mg/kg body weight by oral gavage) and cadmium + extract (400 mg/kg body weight by oral gavage). Changes in the kidney biochemical markers, namely glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), aminotransferase (ALT), aspartate aminotransferase (AST) activities and levels of malondialdehyde (MDA), urea, and creatinine were determined in serum. Histological examinations were monitored. Exposure to Cd lowered the activities of kidney antioxidants, while it increased LPO levels. Levels of all disrupted parameters were alleviated by co-administration of IG extract. The malondialdehyde concentration of the rats treated with 200 and 400 mg/kg body weight of the extract significantly decreased (p<0.05) compared with the untreated cadmium rats. Yet the creatinine concentration decreased significantly (p<0.05) when the cadmium animals treated with 200 and 400 mg/kg body weight of the extract were compared with the cadmium control. Furthermore, histological alterations in the kidney were observed in cadmium untreated rats and these were ameliorated in cadmium treated rats by co-administration of IG extract. IG showed apparent protective and curative effect on Cd-induced nephrotoxicity.

  12. Quantum Yield Enhancement of Cd/Se Colloidal Quantum Dots by Variation of Surface Ligands

    DTIC Science & Technology

    2013-01-01

    a solvent and a ligand, and oleic acid , which also serves as a ligand. The second used more complex ligands, octadecylphosphonic acid , and oleyamine...outgassed for another 30 min. To prepare the Cd precursor 26 mg of cadmium oxide (CdO) powder was mixed with 1.2 ml of oleic acid (OA) and 9.0 ml ODE...Acronyms Ar argon Cd cadmium CdO cadmium oxide OA oleic acid ODE octadecene QD quantum dots QY quantum yield Rh6G rhodamine 6G Se selenium NO. OF

  13. Targeted mapping of Cdu1, a major locus regulating grain cadmium concentration in durum wheat (Triticum turgidum L. var durum)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Some durum wheat (Triticum turgidum L. var durum) cultivars have the genetic propensity to accumulate cadmium (Cd) in the grain. A major gene controlling grain Cd concentration designated as Cdu1 has been reported on 5B, but the genetic factor(s) conferring the low Cd phenotype are currently unknow...

  14. Effects of cadmium-enriched sediment on fish and amphibian embryo-larval stages

    SciTech Connect

    Francis, P.C.; Birge, W.J.; Black, J.A.

    1984-08-01

    Aquatic toxicity tests were conducted to evaluate the effects of cadmium-enriched sediment on embryo-larval stages of the goldfish (Carassius auratus), leopard frog (Rana pipiens), and largemouth bass (Micropterus salmoides). Natural stream sediment was collected and enriched with cadmium to nominal concentrations of 1.0, 10.0, 100, and 1000 mg/kg. Enriched sediments were placed in Pyrex dishes and covered with 350 ml of reconstituted water. Fertilized eggs were placed in the dishes and maintained through 4 days posthatching, giving a total exposure time of 6 to 7 days. For all tests the cadmium concentrations ranged from 1.1 to 76.5 micrograms/liter in water above sediments containing 1 to 1000 mg Cd/kg, respectively. Although low frequencies of mortality were observed in all tests, goldfish, leopard frog, and bass exposed to sediments enriched to 1000 mg Cd/kg accumulated 4.61, 12.55, and 60.0 micrograms Cd/g, respectively. No significant correlations were found between mortality of the goldfish and leopard frog and the cadmium concentrations in either water or sediment. However, all three species showed strong correlations between cadmium concentrations in water and tissue, sediment and tissue, and water and sediment. Tissue cadmium concentrations were related to the length of time test organisms were in direct contact with cadmium-enriched sediment.

  15. Cadmium induced physio-biochemical and molecular response in Brassica juncea.

    PubMed

    Shanmugaraj, Bala Murugan; Chandra, Harish Mani; Srinivasan, Balamurugan; Ramalingam, Sathishkumar

    2013-01-01

    Cadmium is a hazardous heavy metal; its presence in the agricultural soil constrains the crop productivity and restricts crop plants from reaching their full genetic potential. In the present study, two Brassica juncea cultivars (Pusa Bold and Pusa Jaikisan), were exposed to different concentrations of cadmium (Cd) as cadmium chloride (CdCl2) (50 microM, 100 microM, 150 microM, and 200 microM). The effect of cadmium on seed germination ratio, changes in the root and shoot length, plant dry weight, moisture content, metal tolerance index, antioxidant enzyme activity and lipid peroxidation were studied. The consequence of cadmium stress at the molecular level was studied using a key gene Phytochelatin Synthase (PCS). The results of our study suggested that, exposure of cadmium affected the seed germination, growth rate, biomass content and antioxidant enzyme activities in the root, shoot and leaves of both the cultivars. Transcript expression of PCS was increased with increasing CdCl2 concentration in both the cultivars. Based on the results, it was concluded that, Brassica juncea Cv Pusa Jaikisan is more tolerant to cadmium toxicity than the Pusa Bold. These findings could be used to develop heavy metal stress tolerant plants and more importantly, detoxification of heavy metals in the soil.

  16. Toxicological studies of cadmium and zinc on the crayfish Orconectes virilis

    SciTech Connect

    Mirenda, R.J.

    1985-01-01

    The acute toxicities of cadmium and of zinc to the crayfish Oronectes virilis were determined. Adult, intermolt crayfish were exposed to a series of concentrations of either cadmium or zinc for a two week period. Cadmium was found to be a cumulative poison to the crayfish; LC50 values decreased from 6.1 mg Cd/I for 96 hours to 0.7 mg Cd/I for two weeks. An incipient LC50 was also estimated to be 0.0604 mg Cd/I. Zinc was found to have a relatively low toxicity to O. virilis under the present exposure conditions. Whole animal and tissue analyses for cadmium or zinc were performed on the crayfish used in the acute toxicity tests. Whole animals concentrations both for cadmium and for zinc exhibited a linear relationship to exposure concentrations (r = 0.85 and 0.87, respectively). The gills had the highest concentrations (r = 0.85 and 0.87, respectively). The gills had the highest concentrations of cadmium and zinc, and displayed a linear relationship to exposure concentrations (r = 0.82 and 0.87 respectively). The hepatopancreas displayed a plateau in metal concentrations and is probably the main storage site for both metals in the crayfish. The relationship of cadmium concentration to exposure concentration in the antennal glands also showed linearity (r = 0.65), while zinc levels reached a steady state level. All the remaining tissues analyzed exhibited a plateau in metal concentration.

  17. Inducible cadmium binding complexes of cabbage and tobacco

    SciTech Connect

    Wagner, G.J.; Trotter, M.M.

    1982-01-01

    Cadmium complexes with apparent molecular weights of 10,000 were observed in aqueous extracts of Cd-treated cabbage (Brassica capitata L., cv. red danish) and tobacco (hybrid of Nicotiana glauca and N. langsdorffii) plants. The amount of complex (as Cd) recovered was found to be dependent on the concentration of the metal in the growth medium and the total time of exposure of plants to the metal. Induction of the complex at moderate levels of /sup 112/Cd exposure was monitored after labeling the complex with /sup 109/Cd in vitro. The constitutive nature of the ligand of the complex in cabbage and tobacco leaves was suggested when control plant extracts were exposed to /sup 109/Cd. Such extracts contained /sup 109/Cd, which eluted froom Sephadex G-50 in the region of Cd complex. Simultaneous labeling with /sup 112/Cd and /sup 35/S or /sup 32/P indicated that the complex contained sulfur but probably not phosphorus. The amount of /sup 35/S which eluted coincident with /sup 112/Cd complex increased during complex induction. No evidence was found for the presence of 10,000 molecular weight Cd complex in stem exudates (vascular sap) of Cd-treated plants. The results obtained are consistent with the presence in these tissues of a ligand which is both inducible and consitutive and binds Cd in mercaptide bonds. All of these properties and oters reported earlier, are characteristic of Cd-metallothionein formed in animals.

  18. Current status of cadmium as an environmental health problem

    SciTech Connect

    Jaerup, Lars Akesson, Agneta

    2009-08-01

    Cadmium is a toxic metal occurring in the environment naturally and as a pollutant emanating from industrial and agricultural sources. Food is the main source of cadmium intake in the non-smoking population. The bioavailability, retention and toxicity are affected by several factors including nutritional status such as low iron status. Cadmium is efficiently retained in the kidney (half-time 10-30 years) and the concentration is proportional to that in urine (U-Cd). Cadmium is nephrotoxic, initially causing kidney tubular damage. Cadmium can also cause bone damage, either via a direct effect on bone tissue or indirectly as a result of renal dysfunction. After prolonged and/or high exposure the tubular injury may progress to glomerular damage with decreased glomerular filtration rate, and eventually to renal failure. Furthermore, recent data also suggest increased cancer risks and increased mortality in environmentally exposed populations. Dose-response assessment using a variety of early markers of kidney damage has identified U-Cd points of departure for early kidney effects between 0.5 and 3 {mu}g Cd/g creatinine, similar to the points of departure for effects on bone. It can be anticipated that a considerable proportion of the non-smoking adult population has urinary cadmium concentrations of 0.5 {mu}g/g creatinine or higher in non-exposed areas. For smokers this proportion is considerably higher. This implies no margin of safety between the point of departure and the exposure levels in the general population. Therefore, measures should be put in place to reduce exposure to a minimum, and the tolerably daily intake should be set in accordance with recent findings.

  19. Cadmium effects and accumulation in cultures of Prorocentrum micans (dinophyta)

    NASA Astrophysics Data System (ADS)

    Kayser, H.; Sperling, K.-R.

    1980-03-01

    Effects and accumulation of cadmium were studied in unialgal 10-1 batch-culture experiments with the dinoflagellate Prorocentrum micans Ehrenberg. Tests were made using sterile filtered North Sea water enriched with nitrate and phosphate only in order to avoid disturbances by complex formation. Cadmium was added to the cultures in amounts of 100 to 0.13 µg l-1. In one series it was added at the start of the experiments and in a second one after a growth period of 1 week. Addition of only 1.2 µg Cd l-1 reduces multiplication rates and maximum cell densities of the algae. Not until 0.4 µg Cd-1 does growth correspond to that of the controls. Cadmium concentrations were measured, after filtration, in the culture medium and in the biomass by means of flameless AAS. The cadmium content in algae increased from 2.7 µg g-1 (dry weight) in controls to 500 µg g-1 (dry weight) in media containing 100 µg Cd l-1. Uptake occurred rapidly during the first few days of the experiments, slowed down somewhat during exponential growth stage, and increased during decay of the cultures. Cadmium content of culture media remained nearly constant (Series 1) or decreased only slowly during experimental time (Series 2). The highest concentration factor was measured in the controls. It decreased with increasing metal concentration in the medium and increased with experimental time. Structural modifications of the cells were visible after Lugol fixation only, indicating brittleness of the cell walls. P. micans has shown to be extremely sensitive to cadmium and to accumulate this metal.

  20. Chronic Cadmium Exposure Lead to Inhibition of Serum and Hepatic Alkaline Phosphatase Activity in Wistar Rats.

    PubMed

    Treviño, Samuel; Andrade-García, Alejandra; Herrera Camacho, Irma; León-Chavez, Bertha Alicia; Aguilar-Alonso, Patricia; Flores, Gonzalo; Brambila, Eduardo

    2015-12-01

    Alkaline phosphatase (ALP) activity in the serum and liver from rats administered with cadmium (Cd) in drinking water was studied. After metal administration, Cd showed a time-dependent accumulation in the liver, meanwhile metallothionein had a maximum increase at 1 month, remaining in this level until the end of the study. On the other hand, serum and liver ALP activity was decreased after 3 months exposure. To determine if Cd produced an inhibition on enzyme, apo-ALP prepared from both nonexposed and exposed rats was reactivated with Zn, showing 60% more activity as compared with the enzyme isolated from nonexposed rats. In vitro assays showed that Cd-ALP was partially reactivated with Zn; however, in the presence of cadmium, Zn-ALP was completely inhibited. Kinetic studies indicate a noncompetitive inhibition by Cd; these results suggest that Cd can substitute Zn, and/or Cd can interact with nucleophilic ligands essential for the enzymatic activity.

  1. Cadmium induces p53-dependent apoptosis in human prostate epithelial cells.

    PubMed

    Aimola, Pierpaolo; Carmignani, Marco; Volpe, Anna Rita; Di Benedetto, Altomare; Claudio, Luigi; Waalkes, Michael P; van Bokhoven, Adrie; Tokar, Erik J; Claudio, Pier Paolo

    2012-01-01

    Cadmium, a widespread toxic pollutant of occupational and environmental concern, is a known human carcinogen. The prostate is a potential target for cadmium carcinogenesis, although the underlying mechanisms are still unclear. Furthermore, cadmium may induce cell death by apoptosis in various cell types, and it has been hypothesized that a key factor in cadmium-induced malignant transformation is acquisition of apoptotic resistance. We investigated the in vitro effects produced by cadmium exposure in normal or tumor cells derived from human prostate epithelium, including RWPE-1 and its cadmium-transformed derivative CTPE, the primary adenocarcinoma 22Rv1 and CWR-R1 cells and LNCaP, PC-3 and DU145 metastatic cancer cell lines. Cells were treated for 24 hours with different concentrations of CdCl(2) and apoptosis, cell cycle distribution and expression of tumor suppressor proteins were analyzed. Subsequently, cellular response to cadmium was evaluated after siRNA-mediated p53 silencing in wild type p53-expressing RWPE-1 and LNCaP cells, and after adenoviral p53 overexpression in p53-deficient DU145 and PC-3 cell lines. The cell lines exhibited different sensitivity to cadmium, and 24-hour exposure to different CdCl(2) concentrations induced dose- and cell type-dependent apoptotic response and inhibition of cell proliferation that correlated with accumulation of functional p53 and overexpression of p21 in wild type p53-expressing cell lines. On the other hand, p53 silencing was able to suppress cadmium-induced apoptosis. Our results demonstrate that cadmium can induce p53-dependent apoptosis in human prostate epithelial cells and suggest p53 mutation as a possible contributing factor for the acquisition of apoptotic resistance in cadmium prostatic carcinogenesis.

  2. Bioaccumulation and retention kinetics of cadmium in the freshwater decapod Macrobrachium australiense.

    PubMed

    Cresswell, Tom; Simpson, Stuart L; Smith, Ross E W; Nugegoda, Dayanthi; Mazumder, Debashish; Twining, John

    2014-03-01

    The potential sources and mechanisms of cadmium bioaccumulation by the native freshwater decapods Macrobrachium species in the waters of the highly turbid Strickland River in Papua New Guinea were examined using (109)Cd-labelled water and food sources and the Australian species Macrobrachium australiense as a surrogate. Synthetic river water was spiked with environmentally relevant concentrations of cadmium and animals were exposed for 7 days with daily renewal of test solutions. Dietary assimilation of cadmium was assessed through pulse-chase experiments where prawns were fed separately (109)Cd-labelled fine sediment, filamentous algae and carrion (represented by cephalothorax tissue of water-exposed prawns). M. australiense readily accumulated cadmium from the dissolved phase and the uptake rate increased linearly with increasing exposure concentration. A cadmium uptake rate constant of 0.10 ± 0.05 L/g/d was determined in synthetic river water. During depuration following exposure to dissolved cadmium, efflux rates were low (0.9 ± 5%/d) and were not dependent on exposure concentration. Assimilation efficiencies of dietary sources were comparable for sediment and algae (48-51%), but lower for carrion (28 ± 5%) and efflux rates were low (0.2-2.6%/d) demonstrating that cadmium was well retained by M. australiense. A biokinetic model of cadmium accumulation by M. australiense predicted that for exposures to environmentally relevant cadmium concentrations in the Strickland River, uptake from ingestion of fine sediment and carrion would be the predominant sources of cadmium to the organism. The model predicted the total dietary route would represent 70-80% of bioaccumulated cadmium.

  3. Photocatalytic oxidation of cadmium-EDTA with titanium dioxide

    SciTech Connect

    Davis, A.P.; Green, D.L.

    1999-02-15

    Ethylenediaminetetraacetic acid (EDTA) forms stable complexes with toxic metals such as cadmium. Metal-EDTA chelates are chemically stable and occur in a number of waste situations. The viability of using photocatalytic oxidation with titanium dioxide to degrade Cd-EDTA was examined at concentrations from 2 {times} 10{sup {minus}5} to 10{sup {minus}3} M at pH from 3 to 8. Initially a portion of the complex was adsorbed onto the TiO{sub 2} photocatalyst at low pH. However, independent of the degree of initial adsorption, Cd-EDTA was rapidly destroyed with little dependence on pH. Concurrently, in most cases cadmium was liberated as Cd{sup 2+} with no affiliation with organic reaction products; its fate depended on suspension pH. At low pH, Cd{sub aq}{sup 2+} was released into solution. Also, organic carbon was released into solution as oxidation of adsorbed EDTA occurred. At higher pH the Cd was adsorbed onto the TiO{sub 2} at adsorption equilibrium levels. Major products detected include formaldehyde, formic acid, and acetic acid. Nitrate and glyoxylic, malonic, and oxalic acids were detected, but concentrations were low. The incomplete carbon balance and the lack of nitrate production suggest the production of organic amines from the degradation of Cd-EDTA. Release of the Cd as Cd{sup 2+} occurs after mineralization of only about half of the organic carbon.

  4. Physiological responses of two soybean cultivars to cadmium

    SciTech Connect

    Marchiol, L.; Leita, L.; Martin, M.; Peressotti, A.

    1996-05-01

    Anthropogenic activities are increasing cadmium (Cd) concentrations in soils. Cadmium can be absorbed by plant roots and modify the physiology of the plant. Carbon exchange rate (CER) and leaf of two soybean (Glycine max [L.]Merr.) cultivars (Illini insensitive and Richland sensitive) for 6 consecutive days; Cd(NO{sub 3}){sub 2} was added to the hydroponic solution to achieve a final concentration of 50 {mu}mol. At the end of the experiment, stomata length and width, mesophyll limitation to photosynthesis, root hydraulic conductance, relative water content (RWC), and Cd concentration in leaves, stems, and roots were measured on treated and control plants. Cadmium progressively reduced CER and g{sub s} to about 50% after 6 d of treatment. This was more evident in Richland than in Illini and was not linked with leaf RWC and mesophyll limitation to photosynthesis. After 6 d, the apparent root hydraulic water conductivity was 67% lower in the Cd-treated plants than in controls. The primary mechanism affected by Cd-induced stress in soybean is root water uptake, and this reduction is consistent with the decrease in stomatal opening and conductance, and therefore, in photosynthesis. 20 refs., 3 figs., 2 tabs.

  5. The message of nitric oxide in cadmium challenged plants.

    PubMed

    Arasimowicz-Jelonek, Magdalena; Floryszak-Wieczorek, Jolanta; Gwóźdź, Edward A

    2011-11-01

    During the last decade it has been found that cadmium (Cd), one of the most toxic elements occurring in polluted environments, interferes with nitric oxide (NO), a multifunctional signaling molecule in living organisms. The formation of NO has been demonstrated in vivo in various plant tissues exposed to Cd stress, but unfortunately, the time and intensity of NO generation, relatively frequently shows conflicting data. What is more, there is still limited information regarding the functional role of endogenously produced NO in plants challenged with heavy metals. The first pharmacological approaches revealed that exogenously applied NO can alleviate cadmium toxicity in plants, promoting the direct scavenging of reactive oxygen species (ROS) or activating antioxidant enzymes. However, recent reports have indicated that NO even contributes to Cd toxicity by promoting Cd uptake and participates in metal-induced reduction of root growth. In view of this heterogeneous knowledge, much more puzzling if we consider results first obtained using exogenous NO sources, this review is focused mainly on the implication of endogenous NO in plant response to Cd exposure. Furthermore, a basic draft for NO mode of action during cadmium stress is proposed.

  6. First principle study of manganese doped cadmium sulphide sheet

    SciTech Connect

    Kumar, Sanjeev; Kumar, Ashok; Ahluwalia, P. K.

    2014-04-24

    First-principle electronic structure calculations for cadmium sulphide (CdS) sheet in hexagonal phase, with Manganese substitution and addition, as well as including the Cd defects, are investigated. The lattice constants calculated for CdS sheet agrees fairly well with results reported for thin films experimentally. The calculations of total spin density of states and partial density of states in different cases shows substantial magnetic dipole moments acquired by the sheet. A magnetic dipole moment 5.00612 μ{sub B} and band gap of the order 1 eV are found when cadmium atom is replaced by Manganese. The magnetism acquired by the sheet makes it functionally important candidate in many applications.

  7. First principle study of manganese doped cadmium sulphide sheet

    NASA Astrophysics Data System (ADS)

    Kumar, Sanjeev; Kumar, Ashok; Ahluwalia, P. K.

    2014-04-01

    First-principle electronic structure calculations for cadmium sulphide (CdS) sheet in hexagonal phase, with Manganese substitution and addition, as well as including the Cd defects, are investigated. The lattice constants calculated for CdS sheet agrees fairly well with results reported for thin films experimentally. The calculations of total spin density of states and partial density of states in different cases shows substantial magnetic dipole moments acquired by the sheet. A magnetic dipole moment 5.00612 μB and band gap of the order 1 eV are found when cadmium atom is replaced by Manganese. The magnetism acquired by the sheet makes it functionally important candidate in many applications.

  8. Sonochemical synthesis of CdS and CdSe nanowires.

    PubMed

    Jiang, Li-Ping; Xu, Shu; Miao, Jian-Jun; Wang, Hui; Zhu, Jun-Jie

    2006-08-01

    A convenient sonochemical route was developed to fabricate one-dimensional (1D) CdS or CdSe assemblies via a simple template method with two-steps: Firstly, the colloid one dimensional cadmium hydroxide particles were prepared as templates under sonication; then, the colloid particles were converted into 1D CdS or CdSe assemblies via a replacement reaction after the surface nucleation and crystal growth processes. The as-prepared CdS and CdSe nanowires were characterized by XRD, TEM, XPS, and UV-visible Spectroscopy. The effects of the ultrasonic irradiation were discussed. It is believed that the ultrasound irradiation played a positive role in both the assembly of the colloid cadmium hydroxide particles into the 1D structure and the growth of CdSe and CdS nanowires. The effects of pH on the morphologies of the cadmium hydroxide template were also discussed. The band gaps of the as-prepared 1D CdSe and CdS assemblies were calculated to be 3.1 eV and 4.9 eV, respectively, indicating the quantum size effect. The as-prepared products might have potential applications in nanodevices in future.

  9. Chemical speciation of cadmium: An approach to evaluate plant-available cadmium in Ecuadorian soils under cacao production.

    PubMed

    Chavez, E; He, Z L; Stoffella, P J; Mylavarapu, R S; Li, Y C; Baligar, V C

    2016-05-01

    Elevated concentration of cadmium (Cd) in cacao beans has raised serious concerns about the chocolate consumption on human health. Accumulation of Cd in cacao bean in southern Ecuador has been related to soil contamination. In this study, soil fractionation approach was used to identify available Cd pools in the soils and to correlate these Cd pools with bean Cd concentration and soil test indexes. The distribution of soil Cd fractions decreased in the order: oxidizable > acid-soluble > residual > reducible > water-soluble (+exchangeable). Oxidizable and acid-soluble fractions accounted for 59 and 68% of the total recoverable Cd for the 0-5 and 5-15 cm soil depth, respectively. Acid-soluble fraction was closely related to bean-Cd, with correlation coefficients (r) of 0.70 and 0.81 (P < 0.01) for the 0-5 and 5-15 cm soil depth, respectively. Acid-soluble Cd was significantly correlated with 0.01 M HCl- (r = 0.99, P < 0.01) or Mehlich 3- extractable Cd (r = 0.97, P < 0.01). These results indicate that acid-soluble Cd fraction is an important part of available Cd pool. Since approximately 60% of Cd in the cacao-growing soils is related to the acid-soluble fraction and bound to organic matter, remediation of the contaminated soils should consider to the dynamics of soil pH and organic matter content.

  10. Electrical Characterization of Thin Film Cadmium Telluride Electrodeposited from Tri-N Telluride

    NASA Astrophysics Data System (ADS)

    von Windheim, Jesko A.

    The electrical transport properties of CdTe electrodeposited from tri-n-butylphosphine telluride have been studied by resistivity and Hall effect measurements. Methods have been developed to reproducibly remove large area samples from their conducting substrates, and these samples were prepared for temperature dependent Hall measurements and resistivity measurements. Apparatus was designed and built to routinely measure Hall voltages as low as 250 muV for source impedances up to 10 ^{12} Omega. The central aspect of the measurement system was a low cost, differential electrometer amplifier designed around the AD549L monolithic electrometer operational amplifier. Temperature control was achieved via a Eurotherm 808 temperature controller, and a cooled stream of nitrogen gas. With this system, temperature could be maintained within +/- 0.5^circC at set points between -40^circC and +40^circC. Data collection, temperature ramping, and power to the magnet were all computer controlled, and resistivity measurements were fully automated. As-annealed electrodeposited CdTe was found to be consistently p-type, with resistivity values typically 10^6- 10^{7 } Omega-cm. Various donor and acceptor dopants have been incorporated into polycrystalline CdTe films by three methods: electrochemical codeposition, electromigration and vapour techniques. The dopants were Cd, Te, Cu, Ag, In, and O_2. The activity of the dopant was dependent on the method that was used for incorporation. Oxygen was found to only have a significant effect when it was incorporated in situ, during deposition. For Cd and Te, on the other hand, little effect was seen when their concentration was varied in situ. However, hole concentration increased substantially when Te was incorporated by diffusion, and a p to n conversion was observed when Cd was incorporated by diffusion. The carrier concentration of p-type CdTe could be systematically increased by increasing the current density for the electromigration of

  11. Determination of lead, cadmium, indium, thallium and silver in ancient ices from Antarctica by isotope dilution-thermal ionization mass spectrometry

    USGS Publications Warehouse

    Matsumoto, A.; Hinkley, T.K.

    1997-01-01

    The concentrations of five chalcophile elements (Pb, Cd, In, Tl and Ag) and the lead isotope rarios in ancient ices from the Taylor Dome near coastal Antarctica, have been determined by the isotope dilutionthermal ionization mass spectrometry (ID-TIMS), with ultra-clean laboratory techniques. The samples were selected from segments of cores, one of which included a visible ash layer. Electric conductivity measurement (ECM) or dielectric properties (DEP) gave distinctive sharp peaks for some of the samples c hosen. Exterior portions of the sample segments were trimmed away by methods described here. Samples w ere evaporated to dryness and later separated into fractions for the five elements using an HBr-HNO3 a nion exchange column method. The concentrations are in the range 2.62-36.7 pg Pb/g of ice, 0.413-2.83 pg Cd/g, 0.081-0.34 pg In/g, 0.096-2.8 pg Tl/g and 0.15-0.84 pg Ag/g. respectively. The dispersions in duplicate analyses are about ??1% for lead and cadmium, ??2% for indium. ??4% for thallium and ??6% for silver, respectively. The concentrations of lead obtained are commonly higher than those in the present-day Antarctic surface snows, but the isotope ratios are distinctively higher than those of the present-day snows and close to those of the other ancient ice collected from a different Antarctic area.

  12. Cloud point extraction and flame atomic absorption spectrometric determination of cadmium(II), lead(II), palladium(II) and silver(I) in environmental samples.