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Sample records for cadmium sulfide quantum

  1. Luminescent behavior of cadmium sulfide quantum dots for gallic acid estimation

    Science.gov (United States)

    Singh, Suman; Garg, Sourav; Chahal, Jitender; Raheja, Khushboo; Singh, Deepak; Singla, M. L.

    2013-03-01

    Thioglycolic acid capped cadmium sulfide (CdS/T) quantum dots have been synthesized using wet chemistry and their optical behavior has been investigated using UV-visible absorption and fluorescence spectroscopy. The role of the capping agent, sulfide source concentration, pH and temperature has been studied and discussed. Studies showed that alkaline pH leads to a decrease in the size of quantum dots and reflux temperature above 70 °C resulted in red-shift of emission spectra which is due to narrowing of the bandgap. Further, to reduce the toxicity and photochemical instability of quantum dots, the quantum dots have been functionalized with polyethylene glycol (PEG), which resulted in a 20% enhancement of the fluorescence intensity. The application potential of CdS/T-PEG quantum dots was further studied using gallic acid as a model compound. The sensing is based on fluorescence quenching of quantum dots in the presence of gallic acid, and this study showed linearity in the range from 1.3 × 10-8 to 46.5 × 10-8 mM, with a detection limit of 3.6 × 10-8 mM.

  2. Luminescent behavior of cadmium sulfide quantum dots for gallic acid estimation

    International Nuclear Information System (INIS)

    Singh, Suman; Garg, Sourav; Chahal, Jitender; Raheja, Khushboo; Singla, M L; Singh, Deepak

    2013-01-01

    Thioglycolic acid capped cadmium sulfide (CdS/T) quantum dots have been synthesized using wet chemistry and their optical behavior has been investigated using UV–visible absorption and fluorescence spectroscopy. The role of the capping agent, sulfide source concentration, pH and temperature has been studied and discussed. Studies showed that alkaline pH leads to a decrease in the size of quantum dots and reflux temperature above 70 °C resulted in red-shift of emission spectra which is due to narrowing of the bandgap. Further, to reduce the toxicity and photochemical instability of quantum dots, the quantum dots have been functionalized with polyethylene glycol (PEG), which resulted in a 20% enhancement of the fluorescence intensity. The application potential of CdS/T-PEG quantum dots was further studied using gallic acid as a model compound. The sensing is based on fluorescence quenching of quantum dots in the presence of gallic acid, and this study showed linearity in the range from 1.3 × 10 −8 to 46.5 × 10 −8 mM, with a detection limit of 3.6 × 10 −8 mM. (paper)

  3. Cadmium sulfide quantum dots induce oxidative stress and behavioral impairments in the marine clam Scrobicularia plana.

    Science.gov (United States)

    Buffet, Pierre-Emmanuel; Zalouk-Vergnoux, Aurore; Poirier, Laurence; Lopes, Christelle; Risso-de-Faverney, Christine; Guibbolini, Marielle; Gilliland, Douglas; Perrein-Ettajani, Hanane; Valsami-Jones, Eugenia; Mouneyrac, Catherine

    2015-07-01

    Cadmium sulfide (CdS) quantum dots have a number of current applications in electronics and solar cells and significant future potential in medicine. The aim of the present study was to examine the toxic effects of CdS quantum dots on the marine clam Scrobicularia plana exposed for 14 d to these nanomaterials (10 µg Cd L(-1) ) in natural seawater and to compare them with soluble Cd. Measurement of labile Cd released from CdS quantum dots showed that 52% of CdS quantum dots remained in the nanoparticulate form. Clams accumulated the same levels of Cd regardless of the form in which it was delivered (soluble Cd vs CdS quantum dots). However, significant changes in biochemical responses were observed in clams exposed to CdS quantum dots compared with soluble Cd. Increased activities of catalase and glutathione-S-transferase were significantly higher in clams exposed in seawater to Cd as the nanoparticulate versus the soluble form, suggesting a specific nano effect. The behavior of S. plana in sediment showed impairments of foot movements only in the case of exposure to CdS quantum dots. The results show that oxidative stress and behavior biomarkers are sensitive predictors of CdS quantum dots toxicity in S. plana. Such responses, appearing well before changes might occur at the population level, demonstrate the usefulness of this model species and type of biomarker in the assessment of nanoparticle contamination in estuarine ecosystems. © 2015 SETAC.

  4. Cadmium sulfide quantum dots stabilized by castor oil and ricinoleic acid

    Science.gov (United States)

    Kyobe, Joseph William; Mubofu, Egid Beatus; Makame, Yahya M. M.; Mlowe, Sixberth; Revaprasadu, Neerish

    2016-02-01

    Castor oil and ricinoleic acid (an isolate of castor oil) are environmentally friendly bio-based organic surfactants that have been used as capping agents to prepare nearly spherical cadmium sulfide quantum dots (QDs) at 230, 250 and 280 °C. The prepared quantum dots were characterized by Ultra violet-visible (UV-vis), Photoluminescence (PL), Transmission Electron Microscopy (TEM), High Resolution Transmission Electron Microscopy (HRTEM) and X-ray diffraction (XRD) giving an overall CdS QDs average size of 5.14±0.39 nm. The broad XRD pattern and crystal lattice fringes in the HRTEM images showed a hexagonal phase composition of the CdS QDs. The calculated/estimated average size of the prepared castor oil capped CdS QDs for various techniques were 4.64 nm (TEM), 4.65 nm (EMA), 5.35 nm (UV-vis) and 6.46 nm (XRD). For ricinoleic acid capped CdS QDs, the average sizes were 5.56 nm (TEM), 4.78 nm (EMA), 5.52 nm (UV-vis) and 8.21 nm (XRD). Optical properties of CdS QDs showed a change of band gap energy from its bulk band gap of 2.42-2.82 eV due to quantum size confinement effect for temperature range of 230-280 °C. Similarly, a blue shift was observed in the photoluminescence spectra. Scanning electron microscope (SEM) observations show that the as-synthesized CdS QDs structures are spherical in shape. Fourier transform infra-red (FTIR) studies confirms the formation of castor oil and ricinoleic acid capped CdS QDs.

  5. Photoelectrochemical performance of cadmium sulfide quantum dots modified titania nanotube arrays

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Yibing, E-mail: ybxie@seu.edu.cn

    2016-01-01

    The cadmium sulfide quantum dots modified titania nanotube arrays (CdS QDs/TiO{sub 2} NTAs) were prepared through a sequential sonication-assisted chemical bath deposition (CBD) process. The morphology and microstructure of CdS QDs/TiO{sub 2} NTAs were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectroscopy, energy-dispersive X-ray spectroscopy, Raman spectroscopy and UV–vis diffuse reflectance spectroscopy. The photoelectrochemical performance of CdS QDs/TiO{sub 2} NTAs was investigated under solar light illumination. The affecting parameters were studied including the nanotube length of TiO{sub 2} NTAs, CBD cycles of CdS QDs and the annealing treatment of CdS QDs/TiO{sub 2} NTAs. CdS QDs synthesized through 8 CBD cycles could uniformly cover on the tube walls of TiO{sub 2} NTAs to form unique CdS QDs/TiO{sub 2} NTAs with an open pore mouth. The appropriate annealing treatment at 400 °C for 60 min in N{sub 2} atmosphere could improve the crystallinity of CdS QDs, and accordingly enhance the photovoltaic properties of CdS QDs/TiO{sub 2} NTAs. Significantly, the nanotube length was the predominant factor affecting photoelectrochemical performance of CdS QDs/TiO{sub 2} NTAs. The unannealed CdS QDs/TiO{sub 2} NTAs with an optimal nanotube length of 12 μm achieved a short-circuit photocurrent density of 4.37 mA cm{sup −2}, an open circuit photovoltage of 1.10 V and a top photoconversion efficiency of 3.56%. Comparatively, the annealed CdS QDs/TiO{sub 2} NTAs with an optimal nanotube length of 4 μm achieved a short-circuit photocurrent density of 6.31 mA cm{sup −2}, an open circuit photovoltage of 1.23 V and a top photoconversion efficiency of 4.18%. The suitable modification of crystalline CdS QDs could well improve the photoelectrochemical performance of TiO{sub 2} NTAs photoanode. - Highlights: • CdS QDs are uniformly loaded into short and long TiO{sub 2} NTAs to form CdS QDs/TiO{sub 2} NTAs.

  6. Lossless synthesis of graphene nanosheets decorated with tiny cadmium sulfide quantum dots with excellent nonlinear optical properties

    International Nuclear Information System (INIS)

    Feng Miao; Zhan Hongbing; Sun Ruiqing; Chen Yu

    2010-01-01

    The implantation and growth of metal nanoparticles on graphene nanosheets (GNS) leads directly to severe damage to the regular structure of the graphene sheets, which disrupts the extended π conjugation, resulting in an impaired device performance. In this paper, we describe a facile approach for achieving the lossless formation of graphene composite decorated with tiny cadmium sulfide quantum dots (QDs) with excellent nonlinear optical properties by using benzyl mercaptan (BM) as the interlinker. The mercapto substituent of BM binds to the CdS QDs during their nucleation and growth process, and then the phenyl comes into contact with the GNS via the π-π stacking interaction. Using this strategy, CdS QDs with an average diameter of 3 nm are uniformly dispersed over the surface of graphene, and the resulting QD-graphene composite exhibits excellent optical limiting properties, mainly contributed by nonlinear scattering and nonlinear absorption, upon both 532 and 1064 nm excitations, in the nanosecond laser pulse regime.

  7. A fluorescent sensor based on thioglycolic acid capped cadmium sulfide quantum dots for the determination of dopamine

    Science.gov (United States)

    Kulchat, Sirinan; Boonta, Wissuta; Todee, Apinya; Sianglam, Pradthana; Ngeontae, Wittaya

    2018-05-01

    A fluorescent sensor based on thioglycolic acid-capped cadmium sulfide quantum dots (TGA-CdS QDs) has been designed for the sensitive and selective detection of dopamine (DA). In the presence of dopamine (DA), the addition of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) activates the reaction between the carboxylic group of the TGA and the amino group of dopamine to form an amide bond, quenching the fluorescence of the QDs. The fluorescence intensity of TGA-CdS QDs can be used to sense the presence of dopamine with a limit of detection of 0.68 μM and a working linear range of 1.0-17.5 μM. This sensor system shows great potential application for dopamine detection in dopamine drug samples and for future easy-to-make analytical devices.

  8. Improvement of the luminescent properties of cadmium sulfide quantum dots by a post-synthesis modification

    Energy Technology Data Exchange (ETDEWEB)

    López, Israel; Gómez, Idalia, E-mail: maria.gomezd@uanl.edu.mx

    2014-11-15

    Here the improvement of the luminescent properties of CdS quantum dots by a post-synthesis modification with aqueous solutions of NaOH at different concentrations is presented. The CdS quantum dots were synthesized by a microwave-assisted method using citrate ions as stabilizer. The addition of the hydroxide ions increased the intensity of the orange-red emission by about 80%. Besides, a violet-blue emission was achieved by means of this post-synthesis modification. The hydroxide ions control the precipitation equilibria of the CdS and Cd(OH){sub 2}, dissolving and precipitating the surface of the quantum dots. The NaOH treatment increases the number of traps, which produces less band-edge and more deep-trap emission, which explains the decrease and increase in the intensity of the violet-blue and orange-red emissions, respectively.

  9. Improvement of the luminescent properties of cadmium sulfide quantum dots by a post-synthesis modification

    International Nuclear Information System (INIS)

    López, Israel; Gómez, Idalia

    2014-01-01

    Here the improvement of the luminescent properties of CdS quantum dots by a post-synthesis modification with aqueous solutions of NaOH at different concentrations is presented. The CdS quantum dots were synthesized by a microwave-assisted method using citrate ions as stabilizer. The addition of the hydroxide ions increased the intensity of the orange-red emission by about 80%. Besides, a violet-blue emission was achieved by means of this post-synthesis modification. The hydroxide ions control the precipitation equilibria of the CdS and Cd(OH) 2 , dissolving and precipitating the surface of the quantum dots. The NaOH treatment increases the number of traps, which produces less band-edge and more deep-trap emission, which explains the decrease and increase in the intensity of the violet-blue and orange-red emissions, respectively

  10. A novel method for iodate determination using cadmium sulfide quantum dots as fluorescence probes

    International Nuclear Information System (INIS)

    Tang Chunran; Su Zhonghua; Lin Baogang; Huang Haowen; Zeng Yunlong; Li Shuang; Huang He; Wang Yajing; Li Chunxiang; Shen Guoli; Yu Ruqin

    2010-01-01

    We have developed a novel method for the determination of iodate based on the carboxymethyl cellulose-capped CdS quantum dots (QDs). Factors affecting the iodate detection were investigated, and the optimum conditions were determined. Under the optimum conditions, the relative fluorescence intensity of CdS quantum dots was linearly proportional to IO 3 - over a concentration range from 1.0 x 10 -8 to 1.0 x 10 -5 mol L -1 with a correlation coefficient of 0.9987 and a detection limit of 6.0 nmol L -1 . Iodide, being oxidized by bromine to form iodate, was detected indirectly. The method was successfully applied to the determination of iodate and total amount of iodine in table salt samples. The related mechanism was also discussed.

  11. Fluorescence and Cytotoxicity of Cadmium Sulfide Quantum Dots Stabilized on Clay Nanotubes

    Directory of Open Access Journals (Sweden)

    Anna V. Stavitskaya

    2018-05-01

    Full Text Available Quantum dots (QD are widely used for cellular labeling due to enhanced brightness, resistance to photobleaching, and multicolor light emissions. CdS and CdxZn1−xS nanoparticles with sizes of 6–8 nm were synthesized via a ligand assisted technique inside and outside of 50 nm diameter halloysite clay nanotubes (QD were immobilized on the tube’s surface. The halloysite–QD composites were tested by labeling human skin fibroblasts and prostate cancer cells. In human cell cultures, halloysite–QD systems were internalized by living cells, and demonstrated intense and stable fluorescence combined with pronounced nanotube light scattering. The best signal stability was observed for QD that were synthesized externally on the amino-grafted halloysite. The best cell viability was observed for CdxZn1−xS QD immobilized onto the azine-grafted halloysite. The possibility to use QD clay nanotube core-shell nanoarchitectures for the intracellular labeling was demonstrated. A pronounced scattering and fluorescence by halloysite–QD systems allows for their promising usage as markers for biomedical applications.

  12. A bifacial quantum dot-sensitized solar cell with all-cadmium sulfide photoanode

    Science.gov (United States)

    Ma, Chunqing; Tang, Qunwei; Liu, Danyang; Zhao, Zhiyuan; He, Benlin; Chen, Haiyan; Yu, Liangmin

    2015-02-01

    Pursuit of a high power conversion efficiency and reduction of electricity-generation cost has been a persistent objective for quantum dot-sensitized solar cells (QDSSCs). We present here the fabrication of a QDSSC comprising a nanoflower-structured CdS anode, a liquid electrolyte having S2-/Sn2- redox couples, and a transparent CoSe counter electrode. Nanoflower-structured CdS anodes are prepared by a successive ionic layer adsorption and reaction (SILAR) method and subsequently hydrothermal strategy free of any surfactant or template. The CdS nanoparticles synthesized by a SILAR method act as "seed crystal" for growth of CdS nanoflowers. The average electron lifetime is markedly elevated in nanoflower-structured CdS anode in comparison with CdS nanoparticle or nanoporous CdS microsphere anode. Herein, we study the effect of synthesis method on CdS morphology and solar cell's photovoltaic performance, showing a power conversion efficiency of 1.67% and 1.17% for nanoflower-structured CdS QDSSC under front and rear irradiations, respectively.

  13. Nucleo-mitochondrial interaction of yeast in response to cadmium sulfide quantum dot exposure

    International Nuclear Information System (INIS)

    Pasquali, Francesco; Agrimonti, Caterina; Pagano, Luca; Zappettini, Andrea; Villani, Marco; Marmiroli, Marta; White, Jason C.; Marmiroli, Nelson

    2017-01-01

    Highlights: • CdS QDs induce oxidative stress in yeast. • CdS QDs disrupt mitochondrial membrane potentials and morphology. • CdS QDs do not affect mtDNA content. • CdS QDs modify the expression of genes involved in mitochondrial organization and function. • Deletion of some of these genes induces either tolerant or sensitive phenotypes to CdS QDs. - Abstract: Cell sensitivity to quantum dots (QDs) has been attributed to a cascade triggered by oxidative stress leading to apoptosis. The role and function of mitochondria in animal cells are well understood but little information is available on the complex genetic networks that regulate nucleo-mitochondrial interaction. The effect of CdS QD exposure in yeast Saccharomyces cerevisiae was assessed under conditions of limited lethality (<10%), using cell physiological and morphological endpoints. Whole-genomic array analysis and the screening of a deletion mutant library were also carried out. The results showed that QDs: increased the level of reactive oxygen species (ROS) and decreased the level of reduced vs oxidized glutathione (GSH/GSSG); reduced oxygen consumption and the abundance of respiratory cytochromes; disrupted mitochondrial membrane potentials and affected mitochondrial morphology. Exposure affected the capacity of cells to grow on galactose, which requires nucleo-mitochondrial involvement. However, QDs exposure did not materially induce respiratory deficient (RD) mutants but only RD phenocopies. All of these cellular changes were correlated with several key nuclear genes, including TOM5 and FKS1, involved in the maintenance of mitochondrial organization and function. The consequences of these cellular effects are discussed in terms of dysregulation of cell function in response to these “pathological mitochondria”.

  14. Nucleo-mitochondrial interaction of yeast in response to cadmium sulfide quantum dot exposure

    Energy Technology Data Exchange (ETDEWEB)

    Pasquali, Francesco; Agrimonti, Caterina [Department of Life Sciences, University of Parma, Parma (Italy); Pagano, Luca [Department of Life Sciences, University of Parma, Parma (Italy); Stockbridge school of Agriculture, University of Massachusetts, Amherst, MA (United States); The Connecticut Agricultural Experiment Station, New Haven, CT (United States); Zappettini, Andrea; Villani, Marco [IMEM-CNR - Istituto dei Materiali per l' Elettronica ed il Magnetismo, Parma (Italy); Marmiroli, Marta [Department of Life Sciences, University of Parma, Parma (Italy); White, Jason C. [The Connecticut Agricultural Experiment Station, New Haven, CT (United States); Marmiroli, Nelson, E-mail: nelson.marmiroli@unipr.it [Department of Life Sciences, University of Parma, Parma (Italy); CINSA - Consorzio Interuniversitario Nazionale per le Scienze Ambientali, University of Parma, Parma (Italy)

    2017-02-15

    Highlights: • CdS QDs induce oxidative stress in yeast. • CdS QDs disrupt mitochondrial membrane potentials and morphology. • CdS QDs do not affect mtDNA content. • CdS QDs modify the expression of genes involved in mitochondrial organization and function. • Deletion of some of these genes induces either tolerant or sensitive phenotypes to CdS QDs. - Abstract: Cell sensitivity to quantum dots (QDs) has been attributed to a cascade triggered by oxidative stress leading to apoptosis. The role and function of mitochondria in animal cells are well understood but little information is available on the complex genetic networks that regulate nucleo-mitochondrial interaction. The effect of CdS QD exposure in yeast Saccharomyces cerevisiae was assessed under conditions of limited lethality (<10%), using cell physiological and morphological endpoints. Whole-genomic array analysis and the screening of a deletion mutant library were also carried out. The results showed that QDs: increased the level of reactive oxygen species (ROS) and decreased the level of reduced vs oxidized glutathione (GSH/GSSG); reduced oxygen consumption and the abundance of respiratory cytochromes; disrupted mitochondrial membrane potentials and affected mitochondrial morphology. Exposure affected the capacity of cells to grow on galactose, which requires nucleo-mitochondrial involvement. However, QDs exposure did not materially induce respiratory deficient (RD) mutants but only RD phenocopies. All of these cellular changes were correlated with several key nuclear genes, including TOM5 and FKS1, involved in the maintenance of mitochondrial organization and function. The consequences of these cellular effects are discussed in terms of dysregulation of cell function in response to these “pathological mitochondria”.

  15. Cadmium Sulfide Quantum Dot Particles (CdSQD Dispersed in Poly Methyl Methacrylate as an Effective Gamma Counter for the Scintillation Detector

    Directory of Open Access Journals (Sweden)

    Askari Mohammad Bagher

    2017-08-01

    Full Text Available The synthetic material, cadmium sulfide quantum dot particles (CdSQD, using a hydrothermal method was dispersed in poly methyl methacrylate (PMM polymer. In order to study the synthesized quantum dot particles, X-ray diffraction (XRD and Fourier transform infrared spectroscopy (FTIR techniques were applied. Transmission electron microscopy (TEM and scanning electron microscopy (SEM images were also used to study the surface morphology of synthetic quantum dot particles. Energy-dispersive X-ray spectroscopy (EDX test was done for identification of constituent percent of prepared material. Optical properties of CdSQD particles were evaluated by UV-visible and photoluminescence spectroscopy (PL. Finally the capability of CdSQD particles dispersed in poly methyl methacrylate (CdSQD@PMM as a scintillator material was investigated by photomultiplier tube (PMT test. The result of PMT test along with statistical studies showed that the CdSQD@PMM can be applied as a crystalline promising material in the field of inorganic scintillator detectors regarding to the efficiency and economic aspects.

  16. Photocatalytic Conversion of Nitrobenzene to Aniline through Sequential Proton-Coupled One-Electron Transfers from a Cadmium Sulfide Quantum Dot

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Stephen C. [Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States; Bettis Homan, Stephanie [Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States; Weiss, Emily A. [Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States

    2016-01-28

    This paper describes the use of cadmium sulfide quantum dots (CdS QDs) as visible-light photocatalysts for the reduction of nitrobenzene to aniline through six sequential photoinduced, proton-coupled electron transfers. At pH 3.6–4.3, the internal quantum yield of photons-to-reducing electrons is 37.1% over 54 h of illumination, with no apparent decrease in catalyst activity. Monitoring of the QD exciton by transient absorption reveals that, for each step in the catalytic cycle, the sacrificial reductant, 3-mercaptopropionic acid, scavenges the excitonic hole in ~5 ps to form QD•–; electron transfer to nitrobenzene or the intermediates nitrosobenzene and phenylhydroxylamine then occurs on the nanosecond time scale. The rate constants for the single-electron transfer reactions are correlated with the driving forces for the corresponding proton-coupled electron transfers. This result suggests, but does not prove, that electron transfer, not proton transfer, is rate-limiting for these reactions. Nuclear magnetic resonance analysis of the QD–molecule systems shows that the photoproduct aniline, left unprotonated, serves as a poison for the QD catalyst by adsorbing to its surface. Performing the reaction at an acidic pH not only encourages aniline to desorb but also increases the probability of protonated intermediates; the latter effect probably ensures that recruitment of protons is not rate-limiting.

  17. A circular dichroism sensor for Ni{sup 2+} and Co{sup 2+} based on L-cysteine capped cadmium sulfide quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Tedsana, Wimonsiri [Materials Chemistry Research Center, Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Tuntulani, Thawatchai [Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Ngeontae, Wittaya, E-mail: wittayange@kku.ac.th [Materials Chemistry Research Center, Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand)

    2015-03-31

    Highlights: • Demonstrated a new efficient sensor platform based quantum dots. • Used chiral quantum dots as CD sensor for the detection of heavy metal ions for the first time. • The proposed CD sensor showed highest selectivity towards Ni{sup 2+} and Co{sup 2+}. • Low detection limits of 7.33 μM and 1.13 μM for Ni{sup 2+} and Co{sup 2+}, respectively. • Can be used in real water samples comparing with ICP-OES. - Abstract: A new circular dichroism sensor for detecting Ni{sup 2+} and Co{sup 2+} was proposed for the first time using chiral chelating quantum dots. The detection principle was based on changing of circular dichroism signals of the chiral quantum dots when forming a chiral complex with Ni{sup 2+} or Co{sup 2+}. L-Cysteine capped cadmium sulfide quantum dots (L-Cyst-CdS QDs) were proposed as a chiral probe. The CD spectrum of L-Cyst-CdS QDs was significantly changed in the presence of Ni{sup 2+} and Co{sup 2+}. On the other hand, other studied cations did not alter the original CD spectrum. Moreover, when increasing the concentration of Ni{sup 2+} or Co{sup 2+}, the intensity of the CD spectrum linearly increased as a function of concentration and could be useful for the quantitative analysis. The proposed CD sensor showed linear working concentration ranges of 10–60 μM and 4–80 μM with low detection limits of 7.33 μM and 1.13 μM for the detection of Ni{sup 2+} and Co{sup 2+}, respectively. Parameters possibly affected the detection sensitivity such as solution pH and incubation time were studied and optimized. The proposed sensor was applied to detect Ni{sup 2+} and Co{sup 2+} in real water samples, and the results agreed well with the analysis using the standard ICP-OES.

  18. Cadmium sulfide quantum dots/poly(acrylic acid-co-acrylic amide) composite hydrogel synthesized by gamma irradiation

    Science.gov (United States)

    Yang, Tao; Li, Qing; Wen, Wanxin; Hu, Liang; He, Weiwei; Liu, Hanzhou

    2018-04-01

    To improve the durability and stability of quantum dots (QDs) in the composite hydrogel, an irradiation induced reduction and polymerization-crosslinking method was reported herein where CdS QDs could be synthesized in situ and fastened to polymer chains due to the coordination forces between amino groups and CdS nanoparticles. The morphology and photoluminescence (PL) property of the composite hydrogel were studied. The result indicated that the CdS QDs with uniform size were dispersed evenly in the composite hydrogel, and the introduced CdS QDs had no obvious effect on the hydrogel structure. With the increases of reagent concentrations, PL intensity of the composite hydrogel was enhanced; however, the emission wavelength had no change.

  19. Rapid biosynthesis of cadmium sulfide (CdS) nanoparticles using ...

    African Journals Online (AJOL)

    Rapid biosynthesis of cadmium sulfide (CdS) nanoparticles using culture supernatants of Escherichia coli ATCC 8739, Bacillus subtilis ATCC 6633 and Lactobacillus ... The process of extracellular and fast biosynthesis may help in the development of an easy and eco-friendly route for the synthesis of CdS nanoparticles.

  20. Reduction kinetics of zinc and cadmium sulfides with hydrogen

    International Nuclear Information System (INIS)

    Turgenev, I.S.; Kabisov, I.Kh.; Zviadadze, G.N.; Vasil'eva, O.Yu.

    1985-01-01

    Kinetics of reduction processes of zinc sulfide in the temperature range 800-1100 deg C and of cadmium sulfide 600-900 deg C has been stodied. Activation energies and reaction order in terms of hydrogen are calculated. Thermodynamic processes of reduction depend on aggregate state of the metal formed. For vaporous zinc in the temperature range 1050-950 deq C activation energy constitutes 174 kJ/mol, for liquid in the range 900-850 deg - 151 kJ/mol and reaction order in terms of hydrogen is 1.0. For vaporous cadmium in the temperature range 900-700 deg C activation energy constitutes 144 kJ/mol and reaction order in terms of hydrogen is 0.86, for liquid in the range 675-600 deg C 127 kJ/mol and 0.8 respectively. The processes of zinc and cadmium sulfide reduction proceed in kinetic regime and are limited by the rate of chemical reaction

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Photoluminescence spectral study of single cadmium selenide/zinc sulfide colloidal nanocrystals in poly(methyl methacrylate) and quantum dots molecules

    Science.gov (United States)

    Shen, Yaoming

    Quantum dots (QDs)and Nano-crystals (NCs) have been studies for decades. Because of the nanoscale quantum confinement, delta shape like energy density states and narrowband emitters properties, they hold great promise for numerous optoelectronics and photonics applications. They could be used for tunable lasers, white LED, Nano-OLED, non-volatile memory and solar cells. They are also the most promising candidates for the quantum computing. The benefits for NCs over QDs is that NCs can be incorporated into a variety of polymers as well as thin films of bulk semiconductors. These exceptional flexibility and structural control distinguish NCs from the more traditional QD structures fabricated using epitaxial growth techniques. In my research of work, I studied the photoluminescence (PL) and absorption character of ensemble NCs incorporated in Polymethyl methacrylate (PMMA). To understand the behavior of the NCs in PMMA, it is important to measure a singe NC to avoid the inhomogenous broading of many NCs. So I particularly studied the behavior of a single NC in PMMA matrix. A microphotoluminescence setup to optically isolate a single nanocrystal is used. Random spectral shift and blinking behavior (on and off) are found. Addition to that, two color spectral shifting, is a major phenomena found in the system. Other interesting results such as PL intensity changes (decreasing or increasing with time) and quenching effect are observed and explained too. From the correlation function, we can distinguish the phonon replicas. The energy of these phonons can be calculated very accurately from the experiment result. The Huang-Rhys factors can be estimated too. Self-assembled semiconductor quantum dots (QDs), from highly strained-layer heteroepitaxy in the Stranski-Krastanow (S-K) growth mode, have been intensively studied because of the delta-function-like density of states, which is significant for optoelectronic applications. Spontaneous formation of semiconductor quantum

  3. Cadmium sulfide thin films growth by chemical bath deposition

    Science.gov (United States)

    Hariech, S.; Aida, M. S.; Bougdira, J.; Belmahi, M.; Medjahdi, G.; Genève, D.; Attaf, N.; Rinnert, H.

    2018-03-01

    Cadmium sulfide (CdS) thin films have been prepared by a simple technique such as chemical bath deposition (CBD). A set of samples CdS were deposited on glass substrates by varying the bath temperature from 55 to 75 °C at fixed deposition time (25 min) in order to investigate the effect of deposition temperature on CdS films physical properties. The determination of growth activation energy suggests that at low temperature CdS film growth is governed by the release of Cd2+ ions in the solution. The structural characterization indicated that the CdS films structure is cubic or hexagonal with preferential orientation along the direction (111) or (002), respectively. The optical characterization indicated that the films have a fairly high transparency, which varies between 55% and 80% in the visible range of the optical spectrum, the refractive index varies from 1.85 to 2.5 and the optical gap value of which can reach 2.2 eV. It can be suggested that these properties make these films perfectly suitable for their use as window film in thin films based solar cells.

  4. Red coloration by heat treatment of the coprecipitate of cadmium sulfide and mercury(II) sulfide prepared from the nitrates

    International Nuclear Information System (INIS)

    Nakahara, Fujiya

    1979-01-01

    The effects of starting salts on the color, particle size and crystal structure of mercury-cadmium-sulfide pigments were investigated. The coprecipitate (N-S) of cadmium sulfide and mercury (II) sulfide was prepared by adding sodium sulfide solution to a mixed cadmium-mercury (II) nitrate solution. The coprecipitate (C-S) of cadmium sulfide and mercury (II) sulfide was also prepared from the mixed solution of their chlorides by the same method as described above. The coprecipitated products were heat-treated (calcination or hydrothermal treatment) at 350 0 C for 2 hours and subsequent changes in powder properties of both products were compared from each other. The powder properties of N-S, C-S and their heat-treated products were investigated by spectral reflectance, electron microscopy, X-ray diffraction and specific surface area measurements. Sample (N-C) obtained by the calcination of N-S was brown, indicating no red coloration, but the calcined product (C-C) of C-S developed a red color. Cl - and hot water were found to be effective for the red color development of the pigment. The effectiveness was confirmed by calcining N-S in the presence of NaCl or by treating it hydrothermally. It was found that halides other than NaCl, (e.g., NH 4 Cl, KCl, KBr and KI), were also effective for the color development of the pigment. The red samples are solid solutions with a basically hexagonal CdS structure, and it appears that CdS takes up HgS without any apparent structural changes. The particle size of the red samples are larger than those of the non red samples. (author)

  5. Defect-mediated photoluminescence up-conversion in cadmium sulfide nanobelts (Conference Presentation)

    Science.gov (United States)

    Morozov, Yurii; Kuno, Masaru K.

    2017-02-01

    The concept of optical cooling of solids has existed for nearly 90 years ever since Pringsheim proposed a way to cool solids through the annihilation of phonons via phonon-assisted photoluminescence (PL) up-conversion. In this process, energy is removed from the solid by the emission of photons with energies larger than those of incident photons. However, actually realizing optical cooling requires exacting parameters from the condensed phase medium such as near unity external quantum efficiencies as well as existence of a low background absorption. Until recently, laser cooling has only been successfully realized in rare earth doped solids. In semiconductors, optical cooling has very recently been demonstrated in cadmium sulfide (CdS) nanobelts as well as in hybrid lead halide perovskites. For the former, large internal quantum efficiencies, sub-wavelength thicknesses, which decrease light trapping, and low background absorption, all make near unity external quantum yields possible. Net cooling by as much as 40 K has therefore been possible with CdS nanobelts. In this study, we describe a detailed investigation of the nature of efficient anti-Stokes photoluminescence (ASPL) in CdS nanobelts. Temperature-dependent PL up-conversion and optical absorption studies on individual NBs together with frequency-dependent up-converted PL intensity spectroscopies suggest that ASPL in CdS nanobelts is defect-mediated through involvement of defect levels below the band gap.

  6. Cadmium

    NARCIS (Netherlands)

    Meulenbelt, Jan

    2017-01-01

    Together with zinc and mercury, cadmium belongs to group IIb of the periodic table. It can be found in rocks, soil, water, coal, zinc ore, lead ore, and copper ore. In the environment, cadmium is present predominantly as the oxide or as the chloride, sulfide, or sulfate salt. It has no recognizable

  7. Release of dissolved cadmium and sulfur nanoparticles from oxidizing sulfide minerals

    Science.gov (United States)

    Cadmium enrichment (relative to Fe and Zn) in paddy rice grain occurs during the pre-harvest drainage of flooded soil, which causes oxidative dissolution of sulfide minerals present in reduced soil. We investigated this process over a range of environmentally realistic Cdcontain...

  8. Inhibition of sulfate reduction by iron, cadmium and sulfide in granular sludge

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Silva, Blanca M. [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la Presa San Jose 2055, Lomas 4a. Seccion, 78216, San Luis Potosi, S.L.P. (Mexico); Briones-Gallardo, Roberto [Facultad de Ingenieria-Instituto de Metalurgia, Universidad Autonoma de San Luis Potosi, Sierra Leona 550, Lomas 2a. Seccion, 78210, San Luis Potosi, S.L.P. (Mexico); Razo-Flores, Elias [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la Presa San Jose 2055, Lomas 4a. Seccion, 78216, San Luis Potosi, S.L.P. (Mexico); Celis, Lourdes B., E-mail: celis@ipicyt.edu.mx [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la Presa San Jose 2055, Lomas 4a. Seccion, 78216, San Luis Potosi, S.L.P. (Mexico)

    2009-12-15

    This study investigated the inhibition effect of iron, cadmium and sulfide on the substrate utilization rate of sulfate reducing granular sludge. A series of batch experiments in a UASB reactor were conducted with different concentrations of iron (Fe{sup 2+}, 4.0-8.5 mM), cadmium (Cd{sup 2+}, 0.53-3.0 mM) and sulfide (4.2-10.6 mM), the reactor was fed with ethanol at 1 g chemical oxygen demand (COD)/L and sulfate to yield a COD/SO{sub 4}{sup 2-} (g/g) ratio of 0.5. The addition of iron, up to a concentration of 8.1 mM, had a positive effect on the substrate utilization rate which increased 40% compared to the rate obtained without metal addition (0.25 g COD/g VSS-d). Nonetheless, iron concentration of 8.5 mM inhibited the specific substrate utilization rate by 57% compared to the substrate utilization rate obtained in the batch amended with 4.0 mM Fe{sup 2+} (0.44 g COD/g VSS-d). Cadmium had a negative effect on the specific substrate utilization rate at the concentrations tested; at 3.0 mM Cd{sup 2+} the substrate utilization rate was inhibited by 44% compared with the substrate utilization rate without metal addition. Cadmium precipitation with sulfide did not decrease the inhibition of cadmium on sulfate reduction. These results could have important practical implications mainly when considering the application of the sulfate reducing process to treat effluents with high concentrations of sulfate and dissolved metals such as iron and cadmium.

  9. Inhibition of sulfate reduction by iron, cadmium and sulfide in granular sludge

    International Nuclear Information System (INIS)

    Gonzalez-Silva, Blanca M.; Briones-Gallardo, Roberto; Razo-Flores, Elias; Celis, Lourdes B.

    2009-01-01

    This study investigated the inhibition effect of iron, cadmium and sulfide on the substrate utilization rate of sulfate reducing granular sludge. A series of batch experiments in a UASB reactor were conducted with different concentrations of iron (Fe 2+ , 4.0-8.5 mM), cadmium (Cd 2+ , 0.53-3.0 mM) and sulfide (4.2-10.6 mM), the reactor was fed with ethanol at 1 g chemical oxygen demand (COD)/L and sulfate to yield a COD/SO 4 2- (g/g) ratio of 0.5. The addition of iron, up to a concentration of 8.1 mM, had a positive effect on the substrate utilization rate which increased 40% compared to the rate obtained without metal addition (0.25 g COD/g VSS-d). Nonetheless, iron concentration of 8.5 mM inhibited the specific substrate utilization rate by 57% compared to the substrate utilization rate obtained in the batch amended with 4.0 mM Fe 2+ (0.44 g COD/g VSS-d). Cadmium had a negative effect on the specific substrate utilization rate at the concentrations tested; at 3.0 mM Cd 2+ the substrate utilization rate was inhibited by 44% compared with the substrate utilization rate without metal addition. Cadmium precipitation with sulfide did not decrease the inhibition of cadmium on sulfate reduction. These results could have important practical implications mainly when considering the application of the sulfate reducing process to treat effluents with high concentrations of sulfate and dissolved metals such as iron and cadmium.

  10. Preparation and characterization of polyaniline-cadmium sulfide nanocomposite for gas sensor application

    Science.gov (United States)

    Al-Jawad, Selma M. H.; Rafic, Sewench N.; Muhsen, Mustafa M.

    2017-09-01

    Polyaniline (PANI) was prepared by chemical oxidative polymerization of aniline monomers as emeraldine salt form. By the same method, polyaniline-cadmium sulfide nanocomposites were synthesized in the presence of different percentages (10-50 wt.%) of cadmium sulfide (CdS) which was prepared by using sol-gel method. The optical band gap was decrease with increasing of CdS concentration, that is obtained from UV-VIS measurements. From SEM and AFM, there is uniform distribution for cadmium sulfide nanoparticles in the PANI matrix. The electrical measurements of nanocomposites exhibit the effect of crystallite size and the high resistivity of CdS on the resistivity of nanocomposites. Emeraldine salt PANI, CdS and PANI-CdS nanocomposites were investigated as gas sensors. From this investigation, the sensitivity of PANI-CdS for NO2 gas increase with the increasing of operation temperature and the optimum sensitivity was obtained at 200∘C. The sensitivity of nanocomposites at best temperature (200∘C) was increased and faster response time with the increasing of CdS contents.

  11. Aqueous synthesis and characterization of bovine hemoglobin-conjugated cadmium sulfide nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Guangrui [Institute of Environmental and Municipal Engineering, North China University of Water Conservancy and Electric Power, Zhengzhou 450011 (China); Qin, Dezhi, E-mail: dezhiqin@163.com [College of Chemistry and Chemical Engineering, Pingdingshan University, Pingdingshan 467000 (China); Du, Xian; Zhang, Li; Zhao, Ganqing; Zhang, Qiuxia; Wu, Jiulin [College of Chemistry and Chemical Engineering, Pingdingshan University, Pingdingshan 467000 (China)

    2014-08-01

    Highlights: • CdS nanocrystals were synthesized by biomimetic method in bovine hemoglobin (BHb) solution. • The study of the interaction between Cd{sup 2+}/CdS and BHb. • The optical properties of BHb-conjugated CdS nanocrystals. • The synthesis process of BHb-conjugated CdS nanocrystals is facile, effective and environment friendly. • The change of secondary structure of BHb after binding to CdS nanocrystals. - Abstract: Cadmium sulfide (CdS) nanocrystals with average diameter about 5.5 nm were synthesized in aqueous solution of bovine hemoglobin (BHb) via simple biomimetic method. Powder X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and selected area electron diffraction (SAED) characterizations were used to determine the structure and morphology of CdS nanocrystals. It was revealed that amount of BHb, chelating of Cd{sup 2+} to BHb and reaction temperature were key factors in controlling shape and dispersion of CdS nanocrystals. The binding sites of BHb to CdS nanocrystals and the change of secondary structure of protein have been identified by Fourier transform infrared (FT-IR) and circular dichroism (CD) spectroscopy. It was found that conjugating of BHb with Cd{sup 2+} and CdS could protect nanocrystals from agglomerating. Moreover, the thermostability of BHb enhanced after conjugating with CdS nanocrystals. The interaction mechanism of BHb with Cd{sup 2+}/CdS was also proposed. The quantum-confined effect of CdS nanocrystals was confirmed by ultraviolet–visible (UV–vis) spectrum. The nanocrystals exhibited a well-defined photoluminescence (PL) emission feature at about 510 nm with narrow full width at half maximum (FWHM)

  12. Synthesis and Characterization of Cadmium Sulfide Nanoparticles by Chemical Precipitation Method.

    Science.gov (United States)

    Devi, R Aruna; Latha, M; Velumani, S; Oza, Goldie; Reyes-Figueroa, P; Rohini, M; Becerril-Juarez, I G; Lee, Jae-Hyeong; Yi, Junsin

    2015-11-01

    Cadmium sulfide (CdS) nanoparticles were synthesized by chemical precipitation method using cadmium chloride (CdCl2), sodium sulfide (Na2S) and water as a solvent by varying temperatures from 20-80 degrees C. The nanoparticles were characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), High-resolution transmission electron microscopy (HR-TEM) and UV-Visible spectroscopy. XRD pattern revealed cubic crystal structure for all the synthesized CdS nanoparticles. Raman spectra showed first and second order longitudinal optical (LO) phonon vibrational modes of CdS. The size of CdS nanoparticles was found to be in the range of 15-80 nm by FE-SEM analysis, in all cases. The atomic percentage of cadmium and sulfur was confirmed to be 1:1 from EDS analysis. TEM micrograph depicts the spherical shape of the particles and the size is in the range of 15-85 nm while HR-TEM images of CdS nanoparticles exhibit well-resolved lattice fringes of the cubic structure of CdS. The optical properties of CdS were examined by UV-Visible spectroscopy which showed variation in absorption band from 460-480 nm. The band gap was calculated from the absorption edge and found to be in the range of 3.2-3.5 eV which is greater than the bulk CdS.

  13. Fabrication and optical characterization of cadmium sulfide needles using nuclear track membrane

    International Nuclear Information System (INIS)

    Peng, L.Q.; Wang, S.C.; Ju, X.; Xiao, H.; Chen, H.; He, Y.J.

    1999-01-01

    Cadmium sulfide needles with a diameter of 0.2 μm have been fabricated in nuclear track polyethylene-terephthalate (PET) membrane by electrochemically depositing from organic solvent dimethylsulfoxide (DMSO) containing CdCl 2 and elemental sulfur at the temperature 110 deg. C. The characterization of the sample of CdS needles was studied by scanning electron microscope, X-ray diffraction, absorption and photoluminescence spectra. The optical experiments show that in the sample of CdS needles there is an absorption peak that could be assigned to the interface states of the CdS needles

  14. Fabrication and optical characterization of cadmium sulfide needles using nuclear track membrane

    Energy Technology Data Exchange (ETDEWEB)

    Peng, L.Q.; Wang, S.C.; Ju, X.; Xiao, H.; Chen, H.; He, Y.J

    1999-06-01

    Cadmium sulfide needles with a diameter of 0.2 {mu}m have been fabricated in nuclear track polyethylene-terephthalate (PET) membrane by electrochemically depositing from organic solvent dimethylsulfoxide (DMSO) containing CdCl{sub 2} and elemental sulfur at the temperature 110 deg. C. The characterization of the sample of CdS needles was studied by scanning electron microscope, X-ray diffraction, absorption and photoluminescence spectra. The optical experiments show that in the sample of CdS needles there is an absorption peak that could be assigned to the interface states of the CdS needles.

  15. SELF-ORGANIZATION OF LEAD SULFIDE QUANTUM DOTS INTO SUPERSTRUCTURES

    Directory of Open Access Journals (Sweden)

    Elena V. Ushakova

    2014-11-01

    Full Text Available The method of X-ray structural analysis (X-ray scattering at small angles is used to show that the structures obtained by self-organization on a substrate of lead sulfide (PbS quantum dots are ordered arrays. Self-organization of quantum dots occurs at slow evaporation of solvent from a cuvette. The cuvette is a thin layer of mica with teflon ring on it. The positions of peaks in SAXS pattern are used to calculate crystal lattice of obtained ordered structures. Such structures have a primitive orthorhombic crystal lattice. Calculated lattice parameters are: a = 21,1 (nm; b = 36,2 (nm; c = 62,5 (nm. Dimensions of structures are tens of micrometers. The spectral properties of PbS QDs superstructures and kinetic parameters of their luminescence are investigated. Absorption band of superstructures is broadened as compared to the absorption band of the quantum dots in solution; the luminescence band is slightly shifted to the red region of the spectrum, while its bandwidth is not changed much. Luminescence lifetime of obtained structures has been significantly decreased in comparison with the isolated quantum dots in solution, but remained the same for the lead sulfide quantum dots close-packed ensembles. Such superstructures can be used to produce solar cells with improved characteristics.

  16. Synthesis and Characterization of Mercaptoacetic Acid Capped Cadmium Sulphide Quantum Dots.

    Science.gov (United States)

    Wageh, S; Maize, Mai; Donia, A M; Al-Ghamdi, Ahmed A; Umar, Ahmad

    2015-12-01

    This paper reports the facile synthesis and detailed characterization of mercaptoacetic acid capped cadmium sulphide (CdS) quantum dots using various cadmium precursors. The mercaptoacetic acid capped CdS quantum dots were prepared by facile and simple wet chemical method and characterized by several techniques such as energy dispersive spectroscopy (EDS), X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, UV-vis. spectroscopy, photoluminescence spectroscopy, high-resolution transmission microscopy (HRTEM) and thremogravimetric analysis. The EDS studies revealed that the prepared quantum dots possess higher atomic percentage of sulfur compared to cadmium due to the coordination of thiolate to the quantum dots surfaces. The X-ray and absorption analyses exhibited that the size of quantum dots prepared by cadmium acetate is larger than the quantum dots prepared by cadmium chloride and cadmium nitrate. The increase in size can be attributed to the low stability constant of cadmium acetate in comparison with cadmium chloride and cadmium nitrate. The FTIR and thermogravimetric analysis showed that the nature of capping molecule on the surface of quantum dots are different depending on the cadmium precursors which affect the emission from CdS quantum dots. Photoemission spectroscopy revealed that the emission of quantum dots prepared by cadmium acetate has high intensity band edge emission along with low intensity trapping state emission. However the CdS quantum dots prepared by cadmium chloride and cadmium nitrate produced only trapping state emissions.

  17. Temperature dependence of thermal expansion of cadmium sulfide in the temperature range 20 - 820 K

    International Nuclear Information System (INIS)

    Oskotskij, V.S.; Kobyakov, I.B.; Solodukhin, A.V.

    1980-01-01

    The linear thermal expansion of cadmium sulfide is measured perpendicularly (α 1 ) and parallelly (α 2 ) to the hexagonal axis in the temperature range from 20 to 820 K. Anisotropy is low at up to 80 K; rises at higher temperatures; at 3OO K α 1 /α 3 ratio is 1.8; at 820 K, 2.4. Heat expansion is negative at temperatures lower than 104.5 K(α 1 ) and 126.0 K(α 2 ). It achieves the minimum at 43.6 K (α 1 ) and 52.5K (α 3 ). The theory of heat expansion is plotted in the Debue, approximation and cadmium sulfide is considered as an isotope crystal with average elastic constants. Two parameters of the theory are determined by the position and value of the minimum of volumetric thermal expansion of the model isotope crystal. The theoretic curve agrees well with the experimental one at temperatures up to 160 K, i.e in the range of applicability of the Debue approximation and the isotropic model

  18. Aerobic transformation of cadmium through metal sulfide biosynthesis in photosynthetic microorganisms.

    Science.gov (United States)

    Edwards, Chad D; Beatty, Joseph C; Loiselle, Jacqueline B R; Vlassov, Katya A; Lefebvre, Daniel D

    2013-07-15

    Cadmium is a non-essential metal that is toxic because of its interference with essential metals such as iron, calcium and zinc causing numerous detrimental metabolic and cellular effects. The amount of this metal in the environment has increased dramatically since the advent of the industrial age as a result of mining activities, the use of fertilizers and sewage sludge in farming, and discharges from manufacturing activities. The metal bioremediation utility of phototrophic microbes has been demonstrated through their ability to detoxify Hg(II) into HgS under aerobic conditions. Metal sulfides are generally very insoluble and therefore, biologically unavailable. When Cd(II) was exposed to cells it was bioconverted into CdS by the green alga Chlamydomonas reinhardtii, the red alga Cyanidioschyzon merolae, and the cyanobacterium, Synechoccocus leopoliensis. Supplementation of the two eukaryotic algae with extra sulfate, but not sulfite or cysteine, increased their cadmium tolerances as well as their abilities to produce CdS, indicating an involvement of sulfate assimilation in the detoxification process. However, the combined activities of extracted serine acetyl-transferase (SAT) and O-acetylserine(thiol)lyase (OASTL) used to monitor sulfate assimilation, was not significantly elevated during cell treatments that favored sulfide biosynthesis. It is possible that the prolonged incubation of the experiments occurring over two days could have compensated for the low rates of sulfate assimilation. This was also the case for S. leopoliensis where sulfite and cysteine as well as sulfate supplementation enhanced CdS synthesis. In general, conditions that increased cadmium sulfide production also resulted in elevated cysteine desulfhydrase activities, strongly suggesting that cysteine is the direct source of sulfur for CdS synthesis. Cadmium(II) tolerance and CdS formation were significantly enhanced by sulfate supplementation, thus indicating that algae and cyanobacteria

  19. Defect control in room temperature deposited cadmium sulfide thin films by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Como, N. [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX, 75080 (United States); Martinez-Landeros, V. [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX, 75080 (United States); Centro de Investigación en Materiales Avanzados, Monterrey, Nuevo Leon, 66600, México (Mexico); Mejia, I. [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX, 75080 (United States); Aguirre-Tostado, F.S. [Centro de Investigación en Materiales Avanzados, Monterrey, Nuevo Leon, 66600, México (Mexico); Nascimento, C.D.; Azevedo, G. de M; Krug, C. [Instituto de Física, Universidade Federal do Rio Grande do Sul, Porto Alegre, 91509-900 (Brazil); Quevedo-Lopez, M.A., E-mail: mquevedo@utdallas.edu [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX, 75080 (United States)

    2014-01-01

    The control of defects in cadmium sulfide thin films and its impact on the resulting CdS optical and electrical characteristics are studied. Sulfur vacancies and cadmium interstitial concentrations in the CdS films are controlled using the ambient pressure during pulsed laser deposition. CdS film resistivities ranging from 10{sup −1} to 10{sup 4} Ω-cm are achieved. Hall Effect measurements show that the carrier concentration ranges from 10{sup 19} to 10{sup 13} cm{sup −3} and is responsible for the observed resistivity variation. Hall mobility varies from 2 to 12 cm{sup 2}/V-s for the same pressure regime. Although the energy bandgap remains unaffected (∼ 2.42 eV), the optical transmittance is reduced due to the increase of defects in the CdS films. Rutherford back scattering spectroscopy shows the dependence of the CdS films stoichiometry with deposition pressure. The presence of CdS defects is attributed to more energetic species reaching the substrate, inducing surface damage in the CdS films during pulsed laser deposition. - Highlights: • CdS thin films deposited by pulsed laser deposition at room temperature. • The optical, electrical and structural properties were evaluated. • Carrier concentration ranged from 10{sup 19} to 10{sup 13} cm{sup −3}. • The chemical composition was studied by Rutherford back scattering. • The density of sulfur vacancies and cadmium interstitial was varied.

  20. Defect control in room temperature deposited cadmium sulfide thin films by pulsed laser deposition

    International Nuclear Information System (INIS)

    Hernandez-Como, N.; Martinez-Landeros, V.; Mejia, I.; Aguirre-Tostado, F.S.; Nascimento, C.D.; Azevedo, G. de M; Krug, C.; Quevedo-Lopez, M.A.

    2014-01-01

    The control of defects in cadmium sulfide thin films and its impact on the resulting CdS optical and electrical characteristics are studied. Sulfur vacancies and cadmium interstitial concentrations in the CdS films are controlled using the ambient pressure during pulsed laser deposition. CdS film resistivities ranging from 10 −1 to 10 4 Ω-cm are achieved. Hall Effect measurements show that the carrier concentration ranges from 10 19 to 10 13 cm −3 and is responsible for the observed resistivity variation. Hall mobility varies from 2 to 12 cm 2 /V-s for the same pressure regime. Although the energy bandgap remains unaffected (∼ 2.42 eV), the optical transmittance is reduced due to the increase of defects in the CdS films. Rutherford back scattering spectroscopy shows the dependence of the CdS films stoichiometry with deposition pressure. The presence of CdS defects is attributed to more energetic species reaching the substrate, inducing surface damage in the CdS films during pulsed laser deposition. - Highlights: • CdS thin films deposited by pulsed laser deposition at room temperature. • The optical, electrical and structural properties were evaluated. • Carrier concentration ranged from 10 19 to 10 13 cm −3 . • The chemical composition was studied by Rutherford back scattering. • The density of sulfur vacancies and cadmium interstitial was varied

  1. Surface modification of cadmium sulfide thin film honey comb nanostructures: Effect of in situ tin doping using chemical bath deposition

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, K.C., E-mail: wilsonphy@gmail.com [Department of Physics, Govt. Polytechnic College Kothamangalam, Chelad P O, Ernakulam, Kerala 686681 (India); Department of Physics, B. S. Abdur Rahman University, Vandaloor, Chennai, Tamilnadu 600048 (India); Basheer Ahamed, M. [Department of Physics, B. S. Abdur Rahman University, Vandaloor, Chennai, Tamilnadu 600048 (India)

    2016-01-15

    Graphical abstract: - Highlights: • Novel honey comb like cadmium sulfide thin film nanostructures prepared using chemical bath deposition on glass substrates. • Honey comb nanostructure found in two layers: an ultra thin film at bottom and well inter connected with walls of < 25 nm thick on top; hence maximum surface area possible for CdS nanostructure. • Shell size of the nanostructures and energy band gaps were controlled also an enhanced persistent conductivity observed on Sn doping. - Abstract: Even though nanostructures possess large surface to volume ratio compared to their thin film counterpart, the complicated procedure that demands for the deposition on a substrate kept them back foot in device fabrication techniques. In this work, a honey comb like cadmium sulfide (CdS) thin films nanostructure are deposited on glass substrates using simple chemical bath deposition technique at 65 °C. Energy band gaps, film thickness and shell size of the honey comb nanostructures are successfully controlled using tin (Sn) doping and number of shells per unit area is found to be maximum for 5% Sn doped (in the reaction mixture) sample. X-ray diffraction and optical absorption analysis showed that cadmium sulfide and cadmium hydroxide coexist in the samples. TEM measurements showed that CdS nanostructures are embedded in cadmium hydroxide just like “plum pudding”. Persistent photoconductivity measurements of the samples are also carried out. The decay constants found to be increased with increases in Sn doping.

  2. A Study on Dielectric Properties of Cadmium Sulfide-Zinc Sulfide Core-Shell Nanocomposites for Application as Nanoelectronic Filter Component in the Microwave Domain

    Science.gov (United States)

    Devi, Jutika; Datta, Pranayee

    2018-03-01

    Complex permittivities of cadmium sulfide (CdS), zinc sulfide (ZnS), and of cadmium sulfide-zinc sulfide (CdS/ZnS) core-shell nanoparticles embedded in a polyvinyl alcohol matrix (PVA) were measured in liquid phase using a VectorNetwork Analyzer in the frequency range of 500 MHz-10 GHz. These nanocomposites are modeled as an embedded capacitor, and their electric field distribution and polarization have been studied using COMSOL Multiphysics software. By varying the thickness of the shell and the number of inclusions, the capacitance values were estimated. It was observed that CdS, ZnS and CdS/ZnS core-shell nanoparticles embedded in a polyvinyl alcohol matrix show capacitive behavior. There is a strong influence of the dielectric properties in the capacitive behavior of the embedded nanocapacitor. The capping matrix, position and filling factors of nanoinclusions all affect the capacitive behavior of the tested nanocomposites. Application of the CdS, ZnS and CdS/ZnS core-shell nanocomposite as the passive low-pass filter circuit has also been investigated. From the present study, it has been found that CdS/ZnS core-shell nanoparticles embedded in PVA matrix are potential structures for application as nanoelectronic filter components in different areas of communication.

  3. Kinetics and Isotherm of Sunset Yellow Dye Adsorption on Cadmium Sulfide Nanoparticle Loaded on Activated Carbon

    Directory of Open Access Journals (Sweden)

    N. Mosallanejad, A. Arami

    2012-03-01

    Full Text Available The objective of this study was to assess the potential of cadmium sulfide nanoparticles loaded onto activated carbon (CdSN-AC for the removal of sunset yellow (SY dye from aqueous solution. Adsorption studies were conducted in a batch mode varying solution pH, contact time, initial dye concentration, CdSN-AC dose. In order to investigate the efficiency of SY adsorption on CdSN-AC, pseudo-first-order, pseudo-second-order kinetic models were studied. It was observed that the pseudo-second-order kinetic model fits better than other kinetic models with good correlation coefficient. Equilibrium data were fitted to the Langmuir model. It was found that the sorption of SY onto CdSN-AC is followed by these results. 

  4. Nitric oxide-activated hydrogen sulfide is essential for cadmium stress response in bermudagrass (Cynodon dactylon (L). Pers.).

    Science.gov (United States)

    Shi, Haitao; Ye, Tiantian; Chan, Zhulong

    2014-01-01

    Nitric oxide (NO) and hydrogen sulfide (H2S) are important gaseous molecules, serving as important secondary messengers in plant response to various biotic and abiotic stresses. However, the interaction between NO and H2S in plant stress response was largely unclear. In this study, endogenous NO and H2S were evidently induced by cadmium stress treatment in bermudagrass, and exogenous applications of NO donor (sodium nitroprusside, SNP) or H2S donor (sodium hydrosulfide, NaHS) conferred improved cadmium stress tolerance. Additionally, SNP and NaHS treatments alleviated cadmium stress-triggered plant growth inhibition, cell damage and reactive oxygen species (ROS) burst, partly via modulating enzymatic and non-enzymatic antioxidants. Moreover, SNP and NaHS treatments also induced the productions of both NO and H2S in the presence of Cd. Interestingly, combined treatments with inhibitors and scavengers of NO and H2S under cadmium stress condition showed that NO signal could be blocked by both NO and H2S inhibitors and scavengers, while H2S signal was specifically blocked by H2S inhibitors and scavengers, indicating that NO-activated H2S was essential for cadmium stress response. Taken together, we assigned the protective roles of endogenous and exogenous NO and H2S in bermudagrass response to cadmium stress, and speculated that NO-activated H2S might be essential for cadmium stress response in bermudagrass. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  5. Cadmium solubility in paddy soils: Effects of soil oxidation, metal sulfides and competitive ions

    Energy Technology Data Exchange (ETDEWEB)

    Livera, Jennifer de, E-mail: Jennifer.deLivera@adelaide.edu.au [Soil Science, School of Agriculture Food and Wine, Waite Research Institute, University of Adelaide, Adelaide, SA (Australia); McLaughlin, Mike J. [Soil Science, School of Agriculture Food and Wine, Waite Research Institute, University of Adelaide, Adelaide, SA (Australia); CSIRO Land and Water, Environmental Biogeochemistry Program, Sustainable Agriculture Flagship, Adelaide, SA (Australia); Hettiarachchi, Ganga M. [CSIRO Land and Water, Environmental Biogeochemistry Program, Sustainable Agriculture Flagship, Adelaide, SA (Australia); Department of Agronomy, Kansas state University, Manhattan, KS (United States); Kirby, Jason K. [CSIRO Land and Water, Environmental Biogeochemistry Program, Sustainable Agriculture Flagship, Adelaide, SA (Australia); CSIRO Land and Water, Environmental Biogeochemistry Program, Water for a Healthy Country Flagship, Adelaide, SA (Australia); Beak, Douglas G. [CSIRO Land and Water, Environmental Biogeochemistry Program, Sustainable Agriculture Flagship, Adelaide, SA (Australia)

    2011-03-15

    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) and zinc (Zn) for human nutrition. To find ways of limiting this potential risk, we investigated factors influencing Cd solubility relative to Fe and Zn during pre-harvest drainage of paddy soils, in which soil oxidation is accompanied by the grain-filling stage of rice growth. This was simulated in temperature-controlled 'reaction cell' experiments by first excluding oxygen to incubate soil suspensions anaerobically, then inducing aerobic conditions. In treatments without sulfur addition, the ratios of Cd:Fe and Cd:Zn in solution increased during the aerobic phase while Cd concentrations were unaffected and the Fe and Zn concentrations decreased. However, in treatments with added sulfur (as sulfate), up to 34 % of sulfur (S) was precipitated as sulfide minerals during the anaerobic phase and the Cd:Fe and Cd:Zn ratios in solution during the aerobic phase were lower than for treatments without S addition. When S was added, Cd solubility decreased whereas Fe and Zn were unaffected. When soil was spiked with Zn the Cd:Zn ratio was lower in solution during the aerobic phase, due to higher Zn concentrations. Decreased Cd:Fe and Cd:Zn ratios during the grain filling stage could potentially limit Cd enrichment in paddy rice grain due to competitive ion effects for root uptake. - Research Highlights: {yields} Cd:Fe and Cd:Zn ratios increase in paddy soil solution during oxidation. {yields} Cd:Fe and Cd:Zn ratios increase because Fe and Zn concentrations decrease. {yields} Cd concentrations do not change during oxidation. {yields} Cd:Fe and Cd:Zn ratios in solution decrease when Zn is added to soil. {yields} Metal sulfide precipitation lowers Cd:Fe and Cd:Zn ratios in soil solution.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. In situ-synthesized cadmium sulfide nanowire photosensor with a parylene passivation layer for chemiluminescent immunoassays.

    Science.gov (United States)

    Im, Ju-Hee; Kim, Hong-Rae; An, Byoung-Gi; Chang, Young Wook; Kang, Min-Jung; Lee, Tae-Geol; Son, Jin Gyeng; Park, Jae-Gwan; Pyun, Jae-Chul

    2017-06-15

    The direct in situ synthesis of cadmium sulfide (CdS) nanowires (NWs) was presented by direct synthesis of CdS NWs on the gold surface of an interdigitated electrode (IDE). In this work, we investigated the effect of a strong oxidant on the surfaces of the CdS NWs using X-ray photoelectron spectroscopy, transmission electron microscopy, and time-of-flight secondary ion mass spectrometry. We also fabricated a parylene-C film as a surface passivation layer for in situ-synthesized CdS NW photosensors and investigated the influence of the parylene-C passivation layer on the photoresponse during the coating of parylene-C under vacuum using a quartz crystal microbalance and a photoanalyzer. Finally, we used the in situ-synthesized CdS NW photosensor with the parylene-C passivation layer to detect the chemiluminescence of horseradish peroxidase and luminol and applied it to medical detection of carcinoembryonic antigen. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Cadmium Sulfide Nanoparticles Synthesized by Microwave Heating for Hybrid Solar Cell Applications

    Directory of Open Access Journals (Sweden)

    Claudia Martínez-Alonso

    2014-01-01

    Full Text Available Cadmium sulfide nanoparticles (CdS-n are excellent electron acceptor for hybrid solar cell applications. However, the particle size and properties of the CdS-n products depend largely on the synthesis methodologies. In this work, CdS-n were synthetized by microwave heating using thioacetamide (TA or thiourea (TU as sulfur sources. The obtained CdS-n(TA showed a random distribution of hexagonal particles and contained TA residues. The latter could originate the charge carrier recombination process and cause a low photovoltage (Voc, 0.3 V in the hybrid solar cells formed by the inorganic particles and poly(3-hexylthiophene (P3HT. Under similar synthesis conditions, in contrast, CdS-n synthesized with TU consisted of spherical particles with similar size and contained carbonyl groups at their surface. CdS-n(TU could be well dispersed in the nonpolar P3HT solution, leading to a Voc of about 0.6–0.8 V in the resulting CdS-n(TU : P3HT solar cells. The results of this work suggest that the reactant sources in microwave methods can affect the physicochemical properties of the obtained inorganic semiconductor nanoparticles, which finally influenced the photovoltaic performance of related hybrid solar cells.

  9. Luminescent and photocatalytic properties of cadmium sulfide nanoparticles synthesized via microwave irradiation

    International Nuclear Information System (INIS)

    Yang Huaming; Huang Chenghuan; Li Xianwei; Shi Rongrong; Zhang Ke

    2005-01-01

    Uniform cadmium sulfide (CdS) nanoparticles of about 6 nm in crystal size have been successfully synthesized via microwave irradiation. The as-prepared sample has a uniform morphology and high purity. The red photoluminescence spectrum of the CdS nanoparticles displays a strong peak at 602 nm by using a 300 nm excitation wavelength. The photocatalytic oxidation of methyl orange (MeO) in CdS suspensions under ultraviolet illumination was investigated. The results indicate that a low pH value (pH 2.0) and low reaction temperatures (20-30 deg. C) will facilitate the decolorization of the MeO solution. The photodegradation degree decreases with increasing the pH value and temperature of solution. The efficiency of the recycled CdS semiconductor becomes lower due to the deposit of elemental Cd on the CdS surface, which weakens the photocatalytic activity. The luminescent and photocatalytic mechanisms of the as-prepared CdS nanoparticles were primarily discussed. Microwave irradiation is proved to be a convenient, efficient and environmental-friendly one-step route to synthesize nanoparticles

  10. Phase transition in cadmium sulfide single crystals shocked along the c axis

    International Nuclear Information System (INIS)

    Tang, Z.P.; Gupta, Y.M.

    1997-01-01

    Cadmium sulfide crystals were shocked along the crystal c axis to peak stresses ranging between 18 and 75 kbar. Stress-time profiles were measured both at the impact surface and after transmission through 1 to 2-mm-thick samples. Detailed analysis of the present data in combination with published static results makes a persuasive case for the completion of the wurtzite to rocksalt phase change in less than 0.2 μs under shock loading. The main findings are: the transition stress is measured to be 32.5±1kbar; transformation to the final state is a two step process with the first step being too rapid (less than 10 ns) to be observed in our experiments and the second step occurring in 0.1 to 0.2 μs; the transition occurs directly from the elastic state prior to any plastic deformation. The calculated mean stress for the transition is 22.9 kbar in good agreement with the 23 kbar pressure reported in static high pressure studies; the presence of large shear stress has no effect on the transition pressure. Our results suggest that the onset of the phase transition results in plastic deformation and, subsequently, the phase transition and plasticity are coupled under shock loading. copyright 1997 American Institute of Physics

  11. A facile approach to anchor cadmium sulfide nanoparticles on graphene nanosheets as promising electrode materials

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jia; Li, Jing; Yang, Xuyu [Faculty of Materials Science and Engineering, Hubei University, Wuhan 430062 (China); Wang, Xianbao, E-mail: wangxb68@yahoo.com.cn [Faculty of Materials Science and Engineering, Hubei University, Wuhan 430062 (China); Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei University, Wuhan 430062 (China); Wan, Li; Yang, Yingkui [Faculty of Materials Science and Engineering, Hubei University, Wuhan 430062 (China)

    2012-08-15

    A controllable preparation of novel graphene-based inorganic semi-conducting composites has aroused great attention in the optoelectronic device and powerful electronic anode materials. In this article, we demonstrate a simple two-step strategy for the synthesis of cadmium sulfide/reduced graphene oxide (CdS/RGO) nanocomposites, of which the preparing process includes modification of the exfoliated graphene oxide acylated with thionyl chloride, immobilization of the CdS nanoparticles on the graphene oxide (GO) surface by an amide reaction between the amino groups located on the CdS particles and the acyl chloride bound to the GO surface, and reduction by hydrazine and ammonia. Our results showed that the CdS nanoparticles with an average size of 20 nm were homogeneously dispersed on the surface of RGO sheets. The CdS/RGO nanocomposites can form a homogeneous and stable solution in dimethylformamide, and CV analysis indicated a remarkable increase for the CdS/RGO modified electrode in the electrochemical current relative to that at a glass carbon electrode. -- Highlights: Black-Right-Pointing-Pointer CdS/RGO nanocomposites were synthesized by a covalent bonding and electrostatic interaction. Black-Right-Pointing-Pointer CdS/RGO exhibits a homogeneous dispersion in dimethylformamide. Black-Right-Pointing-Pointer CdS/RGO was used as an anode electrode with good electrochemical activity.

  12. Enhanced Performance of Nanoporous Titanium Dioxide Solar Cells Using Cadmium Sulfide and Poly(3-hexylthiophene Co-Sensitizers

    Directory of Open Access Journals (Sweden)

    Murugathas Thanihaichelvan

    2017-09-01

    Full Text Available This work reports the effect of co-sensitization of nanoporous titanium dioxide using Cadmium Sulfide (CdS and poly(3-hexylthiophene (P3HT on the performance of hybrid solar cells. CdS nanolayer with different thicknesses was grown on Titanium Dioxide (TiO2 nanoparticles by chemical bath deposition technique with varying deposition times. Both atomic force microscopy (AFM and UV–Vis–NIR spectroscopy measurements of TiO2 electrode sensitized with and without CdS layer confirm that the existence of CdS layer on TiO2 nanoparticles. AFM images of CdS-coated TiO2 nanoparticles show that the surface roughness of the TiO2 nanoparticle samples decreases with increasing CdS deposition times. Current density–voltage and external quantum efficiency (EQE measurements were carried out for corresponding solar cells. Both short circuit current density (JSC and fill factor were optimized at the CdS deposition time of 12 min. On the other hand, a steady and continuous increment in the open circuit voltage (VOC was observed with increasing CdS deposition time and increased up to 0.81 V when the deposition time was 24 min. This may be attributed to the increased gradual separation of P3HT and TiO2 phases and their isolation at the interfaces. The higher VOC of 0.81 V was due to the higher built-in voltage at the CdS–P3HT interface when compared to that at the TiO2–P3HT interface. Optimized nanoporous TiO2 solar cells with CdS and P3HT co-sensitizers showed external quantum efficiency (EQE of over 40% and 80% at the wavelengths corresponding to strong absorption of the polymer and CdS, respectively. The cells showed an overall average efficiency of over 2.4% under the illumination of 70 mW/cm2 at AM 1.5 condition.

  13. Effects of different annealing atmospheres on the properties of cadmium sulfide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Yücel, E., E-mail: dr.ersinyucel@gmail.com [Department of Physics, Faculty of Arts and Sciences, Mustafa Kemal University, 31034 Hatay (Turkey); Kahraman, S. [Department of Metallurgy and Material Engineering, Faculty of Technology, Mustafa Kemal University, 31034 Hatay (Turkey); Güder, H.S. [Department of Physics, Faculty of Arts and Sciences, Mustafa Kemal University, 31034 Hatay (Turkey)

    2015-08-15

    Graphical abstract: The effects of different annealing atmospheres (air and sulfur) on the structural, morphological and optical properties of CdS thin films were studied at three different pH values. - Highlights: • Compactness and smoothness of the films were enhanced after sulfur annealing. • Micro-strain values of some films were improved after sulfur annealing. • Dislocation density values of some films were improved after sulfur annealing. • Band gap values of the films were improved after sulfur annealing. - Abstract: Cadmium sulfide (CdS) thin films were prepared on glass substrates by using chemical bath deposition (CBD) technique. The effects of different annealing atmospheres (air and sulfur) on the structural, morphological and optical properties of CdS thin films were studied at three different pH values. Compactness and smoothness of the films (especially for pH 10.5 and 11) enhanced after sulfur annealing. pH value of the precursor solution remarkably affected the roughness, uniformity and particle sizes of the films. Based on the analysis of X-ray diffraction (XRD) patterns of the films, micro-strain and dislocation density values of the sulfur-annealed films (pH 10.5 and 11) were found to be lower than those of air-annealed films. Air-annealed films (pH 10.5, 11 and 11.5) exhibited higher transmittance than sulfur-annealed films in the wavelength region of 550–800 nm. Optical band gap values of the films were found between 2.31 eV and 2.36 eV.

  14. Biofabrication of morphology improved cadmium sulfide nanoparticles using Shewanella oneidensis bacterial cells and ionic liquid: For toxicity against brain cancer cell lines.

    Science.gov (United States)

    Wang, Li; Chen, Siyuan; Ding, Yiming; Zhu, Qiang; Zhang, Nijia; Yu, Shuqing

    2018-01-01

    The present work determines the anticancer activity of bio-mediated synthesized cadmium sulfide nanoparticles using the ionic liquid and bacterial cells (Shewanella oneidensis). Bacterial cells have been exposed to be important resources that hold huge potential as ecofriendly, cost-effective, evading toxic of dangerous chemicals and the alternative of conventional physiochemical synthesis. The Shewanella oneidensis is an important kind of metal reducing bacterium, known as its special anaerobic respiratory and sulfate reducing capacity. The crystalline nature, phase purity and surface morphology of biosynthesized cadmium sulfide nanoparticles were analyzed by Fourier transform infrared spectroscopy, X-ray diffraction, Field emission scanning electron microscopy, Energy dispersive spectroscopy and Transmission electron microscopy. The use of imidazolium based ionic liquids as soft templating agent for controlling self-assembly and crystal growth direction of metal sulfide nanoparticles has also advanced as an important method. The microscopic techniques showed that the nanoparticles are designed on the nano form and have an excellent spherical morphology, due to the self-assembled mechanism of ionic liquid assistance. The antitumor efficiency of the cadmium sulfide nanoparticles was investigated against brain cancer cell lines using rat glioma cell lines. The effectively improved nano-crystalline and morphological structure of CdS nanoparticles in the presence of IL exhibit excellent cytotoxicity and dispersion ability on the cell shape is completely spread out showing a nice toxic environment against cancer cells. The cytotoxicity effect of cadmium sulfide nanoparticles was discussed with a diagrammatic representation. Copyright © 2017. Published by Elsevier B.V.

  15. Synthesis, characterization and biocompatibility of cadmium sulfide nanoparticles capped with dextrin for in vivo and in vitro imaging application.

    Science.gov (United States)

    Reyes-Esparza, Jorge; Martínez-Mena, Alberto; Gutiérrez-Sancha, Ivonne; Rodríguez-Fragoso, Patricia; de la Cruz, Gerardo Gonzalez; Mondragón, R; Rodríguez-Fragoso, Lourdes

    2015-11-17

    The safe use in biomedicine of semiconductor nanoparticles, also known as quantum dots (QDs), requires a detailed understanding of the biocompatibility and toxicity of QDs in human beings. The biological characteristics and physicochemical properties of QDs entail new challenges regarding the management of potential adverse health effects following exposure. At certain concentrations, the synthesis of semiconductor nanoparticles of CdS using dextrin as capping agent, at certain concentration, to reduce their toxicity and improves their biocompatibility. This study successfully synthesized and characterized biocompatible dextrin-coated cadmium sulfide nanoparticles (CdS-Dx/QDs). The results show that CdS-Dx/QDs are cytotoxic at high concentrations (>2 μg/mL) in HepG2 and HEK293 cells. At low concentrations (nanoparticles only induced cell death by apoptosis in HEK293 cells at 1 μg/mL concentrations. The in vitro results showed that the cells efficiently took up the CdS-Dx/QDs and this resulted in strong fluorescence. The subcellular localization of CdS-Dx/QDs were usually small and apparently unique in the cytoplasm in HeLa cells but, in the case of HEK293 cells it were more abundant and found in cytoplasm and the nucleus. Animals treated with 100 μg/kg of CdS-Dx/QDs and sacrificed at 3, 7 and 18 h showed a differential distribution in their organs. Intense fluorescence was detected in lung and kidney, with moderate fluorescence detected in liver, spleen and brain. The biocompatibility and toxicity of CdS-Dx/QDs in animals treated daily with 100 μg/kg for 1 week showed the highest level of fluorescence in kidney, liver and brain. Less fluorescence was detected in lung and spleen. There was also evident presence of fluorescence in testis. The histopathological and biochemical analyses showed that CdS-Dx/QDs were non-toxic for rodents. The in vitro and in vivo studies confirmed the effective cellular uptake and even distribution pattern of CdS-Dx/QDs in tissues

  16. Design and characterization of sulfide-modified nanoscale zerovalent iron for cadmium(II) removal from aqueous solutions

    Science.gov (United States)

    Lv, Dan; Zhou, Xiaoxin; Zhou, Jiasheng; Liu, Yuanli; Li, Yizhou; Yang, Kunlun; Lou, Zimo; Baig, Shams Ali; Wu, Donglei; Xu, Xinhua

    2018-06-01

    Nanoscale zero-valent iron (nZVI) has high removal efficiency and strong reductive ability to organic and inorganic contaminants, but concerns over its stability and dispersity limit its application. In this study, nZVI was modified with sulfide to enhance Cd(II) removal from aqueous solutions. TEM and SEM analyses showed that sulfide-modified nZVI (S-nZVI) had a core-shell structure of nano-sized spherical particles, and BET results proved that sulfide modification doubled the specific surface area from 26.04 to 50.34 m2 g-1 and inhibited the aggregation of nZVI. Mechanism analysis indicated that Cd(II) was immobilized through complexation and precipitation. Cd(II) removal rate on nZVI was only 32% in 2 h, while complete immobilization could be achieved in 15 min on S-nZVI, and S-nZVI with an optimal S/Fe molar ratio of 0.3 offered a cadmium removal capacity of about 150 mg g-1 at pH 7 and 303 K. The process of Cd(II) immobilization on S-nZVI was fitted well with pseudo-second-order kinetic model, and the increase of temperature favored Cd(II) immobilization, suggesting an endothermic process. The presence of Mg2+ and Ca2+ hindered Cd(II) removal while Cu2+ did the opposite, which led to the order as Cu2+ > control > Mg2+ > Ca2+. The removal rate of 20 mg L-1 Cd(II) maintained a high level with the fluctuation of environmental conditions such as pH, ion strength and presence of HA. This study demonstrated that S-nZVI could be a promising adsorbent for Cd(II) immobilization from cadmium-contaminated water.

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

    Science.gov (United States)

    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...

  18. Charge transport and trap states in lead sulfide quantum dot field-effect transistors

    NARCIS (Netherlands)

    Nugraha, Mohamad Insan

    2017-01-01

    Lood sulfide Quantum Dots (PbS QDs) hebben grote potentie voor een breed scala aan elektronische apparaten; denk aan zonnecellen, sensors en LEDs. De kwantumopsluiting in deze materialen leidt tot discretie van energieniveaus en afstembaarheid van de bandkloof. Deze materialen zijn ook compatibel

  19. Fluorescence kinetics and positron annihilation kinetics investigations in cadmium sulfide crystals

    Energy Technology Data Exchange (ETDEWEB)

    Grillot, E; Bancie-Grillot, M; Egee, M [Reims Univ., 51 (France)

    1976-03-01

    Fluorescence kinetics and positrons annihilation kinetics investigations on CdS crystals, either very pure or with increasing contents of Ag-ions, led to similar and complementary results. Ag-ions mainly fill the cadmium vacancies of the lattice, building red emission luminogene centres, while green 'edge-emission' ones are destroyed. These latter, which involve an excited level active for high energy series fluorescence, seems actually related to cadmium vacancies.

  20. The effect of tin sulfide quantum dots size on photocatalytic and photovoltaic performance

    International Nuclear Information System (INIS)

    Cheraghizade, Mohsen; Jamali-Sheini, Farid; Yousefi, Ramin; Niknia, Farhad; Mahmoudian, Mohammad Reza; Sookhakian, Mehran

    2017-01-01

    In the current study, tin sulfide Quantum Dots (QDs) was successfully synthesized through sonochemical synthesis method by applying sonication times of 10, 15, and 20 min. Structural studies showed an orthorhombic phase of SnS and Sn_2S_3, and hexagonal phase of SnS_2. The particle size of tin sulfide QDs prepared through sonication time of 20 min was smaller than other QDs. According to TEM images, an increase in sonication time resulted in smaller spherical shaped particles. According to the results of Raman studies, five Raman bands and a shift towards the lower frequencies were observed by enhancing the sonication time. Based on the outcomes of photocatalytic activity, higher this property was observed for tin sulfide QDs, which are prepared through longer sonication time. Solar cell devices manufactured using tin sulfide QDs have a greater performance for the samples with more sonication time. Considering the obtained outcomes, the sonication time seems probable to be a factor affecting synthesis process of SnS QDs as well as its optical and electrical, photocatalytic, and photovoltaic conversion features. - Highlights: • Tin sulfide quantum dots (QDs) synthesized using a sonication method. • The sonication time was selected as a synthesis parameter. • The photocatalytic and photovoltaic performance were depended on synthesis parameter.

  1. The effect of tin sulfide quantum dots size on photocatalytic and photovoltaic performance

    Energy Technology Data Exchange (ETDEWEB)

    Cheraghizade, Mohsen [Young Researchers and Elite Club, Ahvaz Branch, Islamic Azad University, Ahvaz (Iran, Islamic Republic of); Jamali-Sheini, Farid, E-mail: faridjamali@iauahvaz.ac.ir [Advanced Surface Engineering and Nano Materials Research Center, Department of Physics, Ahvaz Branch, Islamic Azad University, Ahvaz (Iran, Islamic Republic of); Yousefi, Ramin [Department of Physics, Masjed-Soleiman Branch, Islamic Azad University (I.A.U), Masjed-Soleiman (Iran, Islamic Republic of); Niknia, Farhad [Young Researchers and Elite Club, Ahvaz Branch, Islamic Azad University, Ahvaz (Iran, Islamic Republic of); Mahmoudian, Mohammad Reza [Department of Chemistry, Shahid Sherafat, University of Farhangian, 15916, Tehran (Iran, Islamic Republic of); Sookhakian, Mehran [Centre for Ionic Liquids, Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia)

    2017-07-01

    In the current study, tin sulfide Quantum Dots (QDs) was successfully synthesized through sonochemical synthesis method by applying sonication times of 10, 15, and 20 min. Structural studies showed an orthorhombic phase of SnS and Sn{sub 2}S{sub 3}, and hexagonal phase of SnS{sub 2}. The particle size of tin sulfide QDs prepared through sonication time of 20 min was smaller than other QDs. According to TEM images, an increase in sonication time resulted in smaller spherical shaped particles. According to the results of Raman studies, five Raman bands and a shift towards the lower frequencies were observed by enhancing the sonication time. Based on the outcomes of photocatalytic activity, higher this property was observed for tin sulfide QDs, which are prepared through longer sonication time. Solar cell devices manufactured using tin sulfide QDs have a greater performance for the samples with more sonication time. Considering the obtained outcomes, the sonication time seems probable to be a factor affecting synthesis process of SnS QDs as well as its optical and electrical, photocatalytic, and photovoltaic conversion features. - Highlights: • Tin sulfide quantum dots (QDs) synthesized using a sonication method. • The sonication time was selected as a synthesis parameter. • The photocatalytic and photovoltaic performance were depended on synthesis parameter.

  2. Cadmium-containing nanoparticles: Perspectives on pharmacology and toxicology of quantum dots

    International Nuclear Information System (INIS)

    Rzigalinski, Beverly A.; Strobl, Jeannine S.

    2009-01-01

    The field of nanotechnology is rapidly expanding with the development of novel nanopharmaceuticals that have potential for revolutionizing medical treatment. The rapid pace of expansion in this field has exceeded the pace of pharmacological and toxicological research on the effects of nanoparticles in the biological environment. The development of cadmium-containing nanoparticles, known as quantum dots, show great promise for treatment and diagnosis of cancer and targeted drug delivery, due to their size-tunable fluorescence and ease of functionalization for tissue targeting. However, information on pharmacology and toxicology of quantum dots needs much further development, making it difficult to assess the risks associated with this new nanotechnology. Further, nanotechnology poses yet another risk for toxic cadmium, which will now enter the biological realm in nano-form. In this review, we discuss cadmium-containing quantum dots and their physicochemical properties at the nano-scale. We summarize the existing work on pharmacology and toxicology of cadmium-containing quantum dots and discuss perspectives in their utility in disease treatment. Finally, we identify critical gaps in our knowledge of cadmium quantum dot toxicity, and how these gaps need to be assessed to enable quantum dot nanotechnology to transit safely from bench to bedside.

  3. Doped cadmium sulfide particles in polymer matrix: X-ray diffraction, optical reflectivity and photoconductivity study

    Czech Academy of Sciences Publication Activity Database

    Franc, Jiří; Nešpůrek, Stanislav; Makarova, Marina; Krtil, Petr

    2008-01-01

    Roč. 10, č. 3 (2008), s. 520-527 ISSN 1454-4164 R&D Projects: GA MPO FT-TA2/018 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z40500505 Keywords : cadmium sulphide * doping * polymer binder * photoconductivity Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.577, year: 2008

  4. Electrical, optical and photoelectric properties of cadmium sulfide monocrystals doped by indium and irradiated by electrons

    CERN Document Server

    Davidyuk, G E; Manzhara, V S

    2002-01-01

    One studied effect of irradiation by E = 1.2 MeV energy and PHI = 2 x 10 sup 1 sup 7 cm sup - sup 2 dose fast electrons on electrical, optical and photoelectrical CdS single-crystals doped by In. On the basis of analysis of the experimental results one makes conclusions about decomposition and, in this case, indium atoms occurring in cation sublattice nodes are knocked out by cadmium atoms. In CdS:In irradiated specimens one detected new centres of slow recombination with occurrence of maximums of photoconductivity optical suppression within lambda sub M sub sub 1 = 0.75 mu m and lambda sub M sub sub 2 = 1.03 mu m range. It is assumed that complexes containing cadmium vacancies and indium atoms are responsible for recombination new centres

  5. Investigation of physicochemical and pigment properties of solid solutions of cadmium, manganese, zinc sulfides

    International Nuclear Information System (INIS)

    Grigor'eva, L.I.; Ignat'eva, I.V.; Kalinskaya, T.V.

    1985-01-01

    Mixed sulfides (Cd, Mn)S and (Cd, Mn, Zn)S with manganese sulfide content upto 50 mol% are synthesized. The possibility of preparing solid solutions both on the basis of silfides (Cd, Mn)S and in the ternary system (Cd, Mn, Zn)S with the temperature of polymorphic transformation of a cubic structure into a hexagonal one, being lower (500 deg C) than in the absence of MnS, is shown by the X-ray diffraction method. The colour analysis of the pigment specimens obtained has shown that the quantity of oxidized manganese compounds, producing no effect of the system colour, should not exceed 0.05 mol% on conversion to MnS. Among the mixed specimens (Cd, Mn)S the brightest colour background is obtained for specimens calcinated at 500-550 deg C. The mixed sulfide of the composition 0.77CdSx0.15MnSx0.08ZnS, calcinated at 500 deg C, gives a pigment corresponding to a commercial one by colour

  6. Some specific features of interaction between light and dislocations in cadmium sulfide

    International Nuclear Information System (INIS)

    Klassen, N.V.; Krasil'nikova, L.L.; Tabeev, Eh.F.

    1977-01-01

    The local spectroscopy of a plastically strained cadmium sulphide is used to study light focusing phenomenon caused by slip bands and light-guide effect of the bands. Such phenomena are strongly dependent on the wavelength and light polarization. The behaviour of the light in the vicinity of slip bands on polarization normal to the bands is adequately explained by photoelastic interaction of the light with dislocations entering into the bands. Explanation of the anomalous behaviour of the light being polarized parallel to the slip bands requires the use of a model taking into consideration the role of localized dislocation states excited by the light of this polarization

  7. A highly stable electrochemiluminescence sensing system of cadmium sulfide nanowires/graphene hybrid for supersensitive detection of pentachlorophenol

    Science.gov (United States)

    Deng, Yanan; Chang, Quanying; Yin, Kai; Liu, Chengbin; Wang, Ying

    2017-10-01

    A highly stable and effective electrochemiluminescence (ECL) sensing system of cadmium sulfide nanowires/reduced graphene oxide (CdS NWS/rGO) hybrid is presented for supersensitive detection of pentachlorophenol (PCP). CdS nanowire is for the first time exploited in ECL sensing. The rGO served as both ECL signal amplifier and immobilization platform, can perfectly enhance the ECL intensity and stability of the sensing system. With S2O82- as coreactant, the ECL signal can be significantly quenched by the addition of PCP. The established ECL sensing system presents a wider linear range from 1.0 × 10-14 to 1.0 × 10-8 M and a much low detection limit of 2 × 10-15 M under the optimum test conditions (e.g., pH 7.0 and 100 mM S2O82-). Furthermore, the ECL sensing system displays a good selectivity for PCP detection. The practicability of the ECL sensing system in real water sample shows that this system could be promisingly applied in the analytical detection of PCP in real water environments.

  8. Enhanced phosphorescence and electroluminescence in triplet emitters by doping gold into cadmium selenide/zinc sulfide nanoparticles

    International Nuclear Information System (INIS)

    Liu, H.-W.; Laskar, Inamur R.; Huang, C.-P.; Cheng, J.-A.; Cheng, S.-S.; Luo, L.-Y.; Wang, H.-R.; Chen, T.-M.

    2005-01-01

    Gold-cadmium selenide/zinc sulfide (Au-CdSe/ZnS) nanocomposites (NCs) were synthesized and characterized by transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis, ultraviolet-visible (UV-visible) absorption and photoluminescence (PL) emission spectroscopy. The PL intensity in the Au-CdSe/ZnS NCs system was found to be much greater than that of CdSe/ZnS nanoparticles (NPs) alone, because of the surface-enhanced Raman scattering of Au NPs. Adding Au-CdSe/ZnS NCs to the cyclometalated iridium(III) complex (Ir-complex) greatly enhanced the PL intensity of a triplet emitter. Three double-layered electroluminescence (EL) devices were fabricated where the emitting zone contains the definite mixture of Ir-complex and the NCs [molar concentration of Ir-complex/NCs = 1:0 (Blank, D-1), 1:1 (D-2) and 1:3 (D-3)] and the device D-2 exhibited optimal EL performances

  9. Size-controlled one-pot synthesis of fluorescent cadmium sulfide semiconductor nanoparticles in an apoferritin cavity

    International Nuclear Information System (INIS)

    Iwahori, K; Yamashita, I

    2008-01-01

    A simple size-controlled synthesis of cadmium sulfide (CdS) nanoparticle (NP) cores in the cavity of apoferritin from horse spleen (HsAFr) was performed by a slow chemical reaction synthesis and a two-step synthesis protocol. We found that the CdS NP core synthesis was slow and that premature CdS NP cores were formed in the apoferritin cavity when the concentration of ammonia water was low. It was proven that the control of the ammonia water concentration can govern the CdS NP core synthesis and successfully produce size-controlled CdS NP cores with diameters from 4.7 to 7.1 nm with narrow size dispersion. X-ray powder diffraction (XRD), energy dispersive spectroscopy (EDS) analysis and high-resolution transmission electron microscopy (HR-TEM) observation characterized the CdS NP cores obtained as cubic polycrystalline NPs, which showed photoluminescence with red shifts depending on their diameters. From the research of CdS NP core synthesis in the recombinant apoferritins, the zeta potential of apoferritin is important for the biomineralization of CdS NP cores in the apoferritin cavity. These synthesized CdS NPs with different photoluminescence properties will be applicable in a wide variety of nano-applications.

  10. Cadmium sulfide/copper ternary heterojunction cell research. Final report, April 1, 1980-August 25, 1982

    Energy Technology Data Exchange (ETDEWEB)

    Mickelsen, R. A.; Chen, W. S.

    1982-08-01

    The properties of polycrystalline, thin-film CuInSe/sub 2//CdS and CuInSe/sub 2//Zn/sub x/Cd/sub 1-x/S solar cells prepared by vacuum-evaporation techniques onto metallized-alumina substrates are described. An efficiency of 10.6% for a 1 cm/sup 2/ area cell and 8.3% for an 8 cm/sup 2/ cell when tested under simulated AM1 illumination is reported. The mixed-sulfide cells are described as exhibiting increased open-circuit voltages, slightly higher short-circuit currents, and improved efficiencies. Mixed-sulfide film preparation by evaporation of CdS and ZnS powders from a single source and from two sources is discussed with preference given to the later technique. Selenide-film preparation in a planetary or rotating substrate vacuum-deposition apparatus is described. A 1 cm/sup 2/ area cell without AR-coating produced by the planetary approach is reported to demonstrate a 7.5% efficiency. The results of cell heat-treatment studies showing a strong environmental dependence are presented and indicate the desirability of an oxygen-containing atmosphere. An automatic, computer-controlled, cell-measurement system for I-V, C-V, and spectral-response analysis is described. The results of the cell-analysis and cell-modeling studies on both the plain CdS and mixed Zn/sub x/Cd/sub 1-x/S thin-film devices are presented. Finally, data obtained from constant illumination and elevated temperature life-tests on the thin-film cells showing little degradation after 9300 hours is reported.

  11. Optoelectronic properties of cadmium sulfide thin films deposited by thermal evaporation technique

    International Nuclear Information System (INIS)

    Ali, N.; Iqbal, M.A.; Hussain, S.T.; Waris, M.; Munair, S.A.

    2011-01-01

    The substrate temperature in depositions of thin films plays a vital role in the characteristics of deposited films. We studied few characteristics of cadmium sulphide thin film deposited at different temperature (150 deg. C- 300 deg. C) on corning 7059 glass substrate. We measured transmittance, absorbance, band gap and reflectance via UV spectroscopy. It was found that the transmittance for 300 nm to 1100 nm was greater than 80%. The resistivity and mobility was calculated by Vander Pauw method which were 10-80 cm and 2-60 cm/sup 2/V/sup -1/S/sup -1/ respectively. The thermoelectric properties of the film were measured by hot and cold probe method which shows the N-type nature of the film. (author)

  12. Optical properties of cadmium sulfide nanocrystal film prepared by electrochemical synthesis at liquid-liquid interface

    International Nuclear Information System (INIS)

    Luan Yemei; An Maozhong; Lu Guoqi

    2006-01-01

    Dendritic nanocrystalline CdS film was deposited at liquid-liquid interface of surfactants and an electrolyte containing 4 mmol L -1 cadmium chloride (CdCl 2 ) and 16 mmol L -1 thioacetamide (CH 3 CSNH 2 ) with an initial pH value of 5 at 15 deg. C by electrochemical synthesis. The nanofilm was characterized by transmission electron microscopy (TEM), field emission scanning electron microscope (FE-SEM), atomic force microscopy (AFM), ultraviolet visible (UV-vis) absorption spectroscopy and fluorescence spectroscopy. The surface morphology and particle size of the nanofilm were investigated by AFM, SEM and TEM, and the crystalline size was 30-50 nm. The thickness of the nanofilm calculated by optical absorption spectrum was 80 nm. The microstructure and composition of the nanofilm was investigated by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), showing its polycrystalline structure consisting of CdS and Cd. Optical properties of the nanofilm were investigated systematically by UV-vis absorption and fluorescence spectroscopy. A λ onset blue shift compared with bulk CdS was observed in the absorption spectra. Fluorescence spectra of the nanofilm indicated that the CdS nanofilm emitted blue and green light. The nanocomposites film electrode will bring about anodic photocurrent during illumination, showing that the transfer of cavities produces photocurrent

  13. Study on concentration nonlinearity of interacting acoustic flows in cadmium sulfide and tellurium

    International Nuclear Information System (INIS)

    Ilisavskij, Yu.V.; Kulakova, L.A.; Yakhkind, Eh.Z.

    1976-01-01

    The ratio of an one-mode (self-action of an external monochromatic sound wave) and a many-mode (interaction of an external wave with crystal thermal phonons) concentration nonlinearity has been experimentally investigated on sound amplification in cadmium sulphide and tellurium. It has been shown that in a strong piezoelectric the main part in the nonlinear limitation of the sound amplification in a drift field is played by the wave interaction, i.e., the transfer of the sound wave energy into the crystal sound modes starts before the nonlinear self-action of a wave. In Te characterized by a large value of the electromechanical coupling constant value at the sound frequency of about 250 MHz the threshold of many-mode nonlinearity is achieved in fields much below the critical one, and corresponds to the sound intensity as low as 10 -7 W/cm 2 , as compared with 10 -2 W/cm 2 -the threshold of the one-mode nonlinearity

  14. Preparation of manganese doped cadmium sulfide nanoparticles in zincblende phase and their magnetic properties.

    Science.gov (United States)

    Nakaya, Masafumi; Tanaka, Itaru; Muramatsu, Atsushi

    2012-12-01

    In this study, the random dope of Mn into CdS nanoparticles in zincblende phase has been carried out under the mild reaction condition. The resulting nanoparticles were characterized by energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), X-ray diffractometer (XRD), UV-Vis spectrometer, PL spectrometer, and SQUID. EDX showed that the compositions of Mn doped CdS nanoparticles were readily controlled. TEM showed the particle sizes were not significantly affected by the compositions, retaining to be ca. 3 nm with a narrow size distribution. UV-Vis and PL spectra of the resulting nanoparticles showed the intra-Mn level may be affected by the quantum size effect. SQUID measurement showed that the resulting nanoparticles showed diamagnetism, paramagnetism and superparamagnetism dependent on Mn content.

  15. Fluorescent cadmium sulfide nanoparticles for selective and sensitive detection of toxic pesticides in aqueous medium

    International Nuclear Information System (INIS)

    Walia, Shanka; Acharya, Amitabha

    2014-01-01

    The detection of pesticide residues in ground water, food, or soil samples is extremely important. The currently available laboratory techniques have several drawbacks and needs to be replaced. Fluorescent chemosensors for pesticide detection were reported in the literature, with few reports published on quantum dot-based pesticide sensors, but none of these were focused toward differentiating organophosphorus and organochlorine pesticides specifically. In this respect, glutathione-coated CdS nanoparticles were synthesized and characterized. The TEM studies of the nanoparticles suggested mostly monodispersed spherical particles, with size in the range of 11.5±1 nm. The prepared fluorescent nanoparticles were found to selectively recognize organochlorine pesticide dicofol among all the other pesticides studied, by increasing the fluorescence intensity of the nanoparticles ∼ 2.5 times. Similar studies carried out with organophosphorous pesticide dimethoate did not result any change in the fluorescence intensity of the nanoparticles. Further studies carried out with commercially available pesticide solutions, also confirmed similar results. The TEM, SEM, and DLS studies suggested aggregation of the nanoparticles in the presence of dicofol. Control experiments suggested possible role of both amine and carboxylic acid functional groups of glutathione in the recognition of dicofol. The limit of detection of dicofol was found to be ∼ 55±11 ppb.Graphical AbstractGlutathione-coated CdS nanoparticles selectively recognize organochlorine pesticide dicofol among all the other pesticides studied, by increasing the fluorescence intensity of the nanoparticles. The TEM, SEM, and DLS studies suggested aggregation of the nanoparticles in the presence of dicofol

  16. Fluorescent cadmium sulfide nanoparticles for selective and sensitive detection of toxic pesticides in aqueous medium

    Energy Technology Data Exchange (ETDEWEB)

    Walia, Shanka; Acharya, Amitabha, E-mail: amitabhachem@gmail.com [CSIR-Institute of Himalayan Bioresource Technology, Biotechnology Division (India)

    2014-12-15

    The detection of pesticide residues in ground water, food, or soil samples is extremely important. The currently available laboratory techniques have several drawbacks and needs to be replaced. Fluorescent chemosensors for pesticide detection were reported in the literature, with few reports published on quantum dot-based pesticide sensors, but none of these were focused toward differentiating organophosphorus and organochlorine pesticides specifically. In this respect, glutathione-coated CdS nanoparticles were synthesized and characterized. The TEM studies of the nanoparticles suggested mostly monodispersed spherical particles, with size in the range of 11.5±1 nm. The prepared fluorescent nanoparticles were found to selectively recognize organochlorine pesticide dicofol among all the other pesticides studied, by increasing the fluorescence intensity of the nanoparticles ∼ 2.5 times. Similar studies carried out with organophosphorous pesticide dimethoate did not result any change in the fluorescence intensity of the nanoparticles. Further studies carried out with commercially available pesticide solutions, also confirmed similar results. The TEM, SEM, and DLS studies suggested aggregation of the nanoparticles in the presence of dicofol. Control experiments suggested possible role of both amine and carboxylic acid functional groups of glutathione in the recognition of dicofol. The limit of detection of dicofol was found to be ∼ 55±11 ppb.Graphical AbstractGlutathione-coated CdS nanoparticles selectively recognize organochlorine pesticide dicofol among all the other pesticides studied, by increasing the fluorescence intensity of the nanoparticles. The TEM, SEM, and DLS studies suggested aggregation of the nanoparticles in the presence of dicofol.

  17. Investigations of the thermal treatment effect on the generation of cadmium sulfide clusters in polymeric films

    International Nuclear Information System (INIS)

    Stanculescu, Anca; Socol, M.; Stanculescu, F.

    2002-01-01

    In the last years a special interest has been paid to the field of nanometer-sized semiconductor compound crystalline clusters synthesized in different matrix (inorganic or organic), due to their special physical and chemical properties intermediate between the molecular and bulk limits. To obtain the thin film samples of CdS particles embedded in a polymeric transparent matrix, as bisphenol A polycarbonate, we followed a process containing three important steps: preparation of the so-called 'mother solution', film deposition and thermal treatment. The samples obtained after the first two steps were heat treated at different temperatures (90 deg. C and 150 deg. C) for 0.5 h, 1 h and 1.5 h, and we have analyzed the influence of these parameters on the film quality using UV-VIS spectrophotometric methods. This paper presents a study of the influence of the thermal treatment on the CdS clusters' generation process and film quality and homogeneity. The parameters of the processing procedure of the polymeric film, as the cooling rate, have a great influence on the rate of germination and development of the crystalline phase. A slow cooling rate is a more favorable process for CdS clusters' formation, indicated .by structured features of the fundamental absorption situated between 350-450 nm. When the temperature for thermal treatment increases to 90 deg. C a sharp rise and a shift to shorter wavelengths of the absorption onset edge was observed. This shift proves the existence of a weak quantum confinement effects. We concluded that these two parameters have some equivalent effects on the CdS clusters' generation in polymeric matrix. Varying the treatment duration with a fixed temperature produces similar results as the fixed duration, varied temperature treatment. (authors)

  18. Biosynthesis and characterization of cadmium sulfide nanoparticles – An emphasis of zeta potential behavior due to capping

    International Nuclear Information System (INIS)

    Sankhla, Aryan; Sharma, Rajeshwar; Yadav, Raghvendra Singh; Kashyap, Diwakar; Kothari, S.L.; Kachhwaha, S.

    2016-01-01

    Biological approaches have been amongst the most promising protocols for synthesis of nanomaterials. In this study, Cadmium sulfide nanoparticles (CdS NPs) were synthesized by incubating their precursor salts with Escherichia coli and zeta potential (ζ-potential) measurement with varying pH was carried out to evaluate stability of the colloidal dispersion. Formation of CdS NPs was studied in synchrony with microbial growth. TEM analysis confirmed the uniform distribution of NPs. Average size (5 ± 0.4 nm) and electron diffraction pattern revealed polycrystalline cubic crystal phase of these nanoparticles. X-ray diffractogram ascertained the formation of CdS nanoparticles with phase formation and particle size distribution in accordance with the particle size obtained from TEM. Absorption edge of biosynthesized CdS NPs showed a blue shift at ∼400 nm in comparison to their bulk counterpart. A hump at 279 nm indicated presence of biomolecules in the solution in addition to the particles. FT-IR spectrum of capped CdS NPs showed peaks of protein. This confirms adsorption of protein molecules on nanoparticle surface. They act as a capping agent hence responsible for the stability of NPs. The enhanced stability of the particles was confirmed by Zeta potential analysis. The presence of charge on the surface of capped CdS NPs gave a detail understanding of dispersion mechanism and colloidal stability at the NP interface. This stability study of biosynthesized semiconductor nanoparticles utilizing microbial cells had not been done in the past by any research group providing an impetus for the same. Surface area of capped CdS NPs and bare CdS NPs were found to be 298 ± 2.65 m 2 /g and 117 ± 2.41 m 2 /g respectively. A possible mechanism is also proposed for the biosynthesis of CdS NPs. - Highlights: • Synthesis of CdS NPs utilizing reproducible molecular machinery viz. Escherichia coli biomass. • Uniform and Polydispersed NPs with high surface area and

  19. Biosynthesis and characterization of cadmium sulfide nanoparticles – An emphasis of zeta potential behavior due to capping

    Energy Technology Data Exchange (ETDEWEB)

    Sankhla, Aryan, E-mail: aaryansankhla@gmail.com [Centre for Converging Technologies, University of Rajasthan, Jaipur, 302015 (India); Sharma, Rajeshwar; Yadav, Raghvendra Singh [Centre for Converging Technologies, University of Rajasthan, Jaipur, 302015 (India); Kashyap, Diwakar [Department of Biological Chemistry, Ariel University, Ariel, 40700 (Israel); Kothari, S.L. [Institute of Biotechnology, Amity University, Jaipur, 303002 (India); Kachhwaha, S. [Department of Botany, University of Rajasthan, Jaipur, 302004 (India)

    2016-02-15

    Biological approaches have been amongst the most promising protocols for synthesis of nanomaterials. In this study, Cadmium sulfide nanoparticles (CdS NPs) were synthesized by incubating their precursor salts with Escherichia coli and zeta potential (ζ-potential) measurement with varying pH was carried out to evaluate stability of the colloidal dispersion. Formation of CdS NPs was studied in synchrony with microbial growth. TEM analysis confirmed the uniform distribution of NPs. Average size (5 ± 0.4 nm) and electron diffraction pattern revealed polycrystalline cubic crystal phase of these nanoparticles. X-ray diffractogram ascertained the formation of CdS nanoparticles with phase formation and particle size distribution in accordance with the particle size obtained from TEM. Absorption edge of biosynthesized CdS NPs showed a blue shift at ∼400 nm in comparison to their bulk counterpart. A hump at 279 nm indicated presence of biomolecules in the solution in addition to the particles. FT-IR spectrum of capped CdS NPs showed peaks of protein. This confirms adsorption of protein molecules on nanoparticle surface. They act as a capping agent hence responsible for the stability of NPs. The enhanced stability of the particles was confirmed by Zeta potential analysis. The presence of charge on the surface of capped CdS NPs gave a detail understanding of dispersion mechanism and colloidal stability at the NP interface. This stability study of biosynthesized semiconductor nanoparticles utilizing microbial cells had not been done in the past by any research group providing an impetus for the same. Surface area of capped CdS NPs and bare CdS NPs were found to be 298 ± 2.65 m{sup 2}/g and 117 ± 2.41 m{sup 2}/g respectively. A possible mechanism is also proposed for the biosynthesis of CdS NPs. - Highlights: • Synthesis of CdS NPs utilizing reproducible molecular machinery viz. Escherichia coli biomass. • Uniform and Polydispersed NPs with high surface area

  20. Colloidal 3-Mercaptopropionic Acid Capped Lead Sulfide Quantum Dots in a Low Boiling Point Solvent.

    Science.gov (United States)

    Reinhart, Chase C; Johansson, Erik

    2017-04-26

    Colloidal 3-mercaptopropionic acid (3-MPA) capped lead sulfide quantum dots were prepared in a variety of organic solvents stabilized with a quaternary ammonium halide salt. The stabilized colloids' optical properties were studied through optical absorption and emission spectroscopy and found to be dependent on both the concentration of a new ligand and stabilizer, and sample age. Nanocrystal ligand chemistry was studied through a combination of 1 H NMR and two-dimensional Nuclear Overhauser Effect Spectroscopy (NOESY) which revealed full displacement of the original oleate ligand to form a dynamically exchanging ligand shell. The colloids were studied optically and via NMR as they aged and revealed a quantitative conversion of monomeric 3-mercaptopropionic acid to its dimer, dithiodipropionic acid (dTdPA).

  1. Carbon nanotube/metal-sulfide composite flexible electrodes for high-performance quantum dot-sensitized solar cells and supercapacitors.

    Science.gov (United States)

    Muralee Gopi, Chandu V V; Ravi, Seenu; Rao, S Srinivasa; Eswar Reddy, Araveeti; Kim, Hee-Je

    2017-04-19

    Carbon nanotubes (CNT) and metal sulfides have attracted considerable attention owing to their outstanding properties and multiple application areas, such as electrochemical energy conversion and energy storage. Here we describes a cost-effective and facile solution approach to the preparation of metal sulfides (PbS, CuS, CoS, and NiS) grown directly on CNTs, such as CNT/PbS, CNT/CuS, CNT/CoS, and CNT/NiS flexible electrodes for quantum dot-sensitized solar cells (QDSSCs) and supercapacitors (SCs). X-ray photoelectron spectroscopy, X-ray diffraction, and transmission electron microscopy confirmed that the CNT network was covered with high-purity metal sulfide compounds. QDSSCs equipped with the CNT/NiS counter electrode (CE) showed an impressive energy conversion efficiency (η) of 6.41% and remarkable stability. Interestingly, the assembled symmetric CNT/NiS-based polysulfide SC device exhibited a maximal energy density of 35.39 W h kg -1 and superior cycling durability with 98.39% retention after 1,000 cycles compared to the other CNT/metal-sulfides. The elevated performance of the composites was attributed mainly to the good conductivity, high surface area with mesoporous structures and stability of the CNTs and the high electrocatalytic activity of the metal sulfides. Overall, the designed composite CNT/metal-sulfide electrodes offer an important guideline for the development of next level energy conversion and energy storage devices.

  2. Studying the state of the surface and internal mass of powder-like zinc and cadmium sulfides

    International Nuclear Information System (INIS)

    Bundel', A.A.; Khozhainov, Yu.M.

    1979-01-01

    The investigation on the chemical and the phase composition of the surface and the bulk of powder zinc and cadmium sulphides as a function of the conditions of ignition and physico-chemical processing carried out using electron diffraction, X-ray phase and chemical analyses. The electron diffraction analysis has shown that ignition gives rise to zinc oxide on the surface of zinc sulphide particles and in the case of cadmium sulphide, to metallic cadmium. To obtain a pure zinc sulphide, free from its oxide both on the surface and in bulk, use should be made of a deoxidized preparation and all contact with oxidizing medium in subsequent ignition should be eliminated

  3. A simple route for making surfactant free lead sulfide (PbS) quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Alam, Firoz; Kumar, Neetesh; Dutta, Viresh, E-mail: vdutta@ces.iitd.ac.in

    2015-05-15

    Highlights: • Surfactant free PbS NCs were successfully synthesised using CoSP technique. • The technique eliminates the requirements of washing to remove the ligands. • Grinding using mortar and pestle creates well separated PbS QDs. • Surfactant free PbS NCs are stable and do not show any degradation with time. - Abstract: An efficient, cost effective and less time consuming method suitable for mass production of surfactant free quantum dots (QDs) of lead sulfide (PbS) is reported. PbS nanocrystals (NCs) are first synthesised by continuous spray pyrolysis (CoSP) technique and de-agglomeration into PbS quantum dots (QDs) is achieved by vigorous mechanical grinding using mortar and pestle. Lead acetate and thiourea were used as the precursor materials for preparation of surfactant free PbS NCs. The broadening in XRD peaks of ground NCs as compared to as synthesized PbS NCs clearly indicated the reduction in particle size to be QDs of PbS. The TEM images also showed that ground PbS NCs were nearly spherical in shape having an average diameter in the range of 4–6 nm. The shift in optical gap from 0.41 eV to 1.47 eV supported the QD formation.

  4. Pure zinc sulfide quantum dot as highly selective luminescent probe for determination of hazardous cyanide ion

    International Nuclear Information System (INIS)

    Shamsipur, Mojtaba; Rajabi, Hamid Reza

    2014-01-01

    A rapid and simple fluorescence method is presented for selective and sensitive determination of hazardous cyanide ion in aqueous solution based on functionalized zinc sulfide (ZnS) quantum dot (QD) as luminescent prob. The ultra-small ZnS QDs were synthesized using a chemical co-precipitation method in the presence of 2-mercaptoethanol (ME) as an efficient capping agent. The prepared pure ZnS QDs was applied as an optical sensor for determination of cyanide ions in aqueous solutions. ZnS nanoparticles have exhibited a strong fluorescent emission at about 424 nm. The fluorescence intensity of QDs is linearly proportional to the cyanide ion concentration in the range 2.44 × 10 −6 to 2.59 × 10 −5 M with a detection limit of 1.70 × 10 −7 M at pH 11. The designed fluorescent sensor possesses remarkable selectivity for cyanide ion over other anions such as Cl − , Br − , F − , I − , IO 3 − , ClO 4 − , BrO 3 − , CO 3 2− , NO 2 − , NO 3 − , SO 4 2− , S 2 O 4 2− , C 2 O 4 2− , SCN − , N 3 − , citrate and tartarate with negligible influences on the cyanide detection by fluorescence spectroscopy. - Highlights: • Preparation of functionalized ZnS quantum dots in aqueous media • Highly selective quantum dot based luminescent probe for determination of cyanide • Fast and sensitive determination of hazardous CN − by fluorescence quenching

  5. Pure zinc sulfide quantum dot as highly selective luminescent probe for determination of hazardous cyanide ion

    Energy Technology Data Exchange (ETDEWEB)

    Shamsipur, Mojtaba, E-mail: mshamsipur@yahoo.com [Department of Chemistry, Razi University, Kermanshah (Iran, Islamic Republic of); Rajabi, Hamid Reza, E-mail: h.rajabi@mail.yu.ac.ir [Chemistry Department, Yasouj University, Yasouj 75918-74831 (Iran, Islamic Republic of)

    2014-03-01

    A rapid and simple fluorescence method is presented for selective and sensitive determination of hazardous cyanide ion in aqueous solution based on functionalized zinc sulfide (ZnS) quantum dot (QD) as luminescent prob. The ultra-small ZnS QDs were synthesized using a chemical co-precipitation method in the presence of 2-mercaptoethanol (ME) as an efficient capping agent. The prepared pure ZnS QDs was applied as an optical sensor for determination of cyanide ions in aqueous solutions. ZnS nanoparticles have exhibited a strong fluorescent emission at about 424 nm. The fluorescence intensity of QDs is linearly proportional to the cyanide ion concentration in the range 2.44 × 10{sup −6} to 2.59 × 10{sup −5} M with a detection limit of 1.70 × 10{sup −7} M at pH 11. The designed fluorescent sensor possesses remarkable selectivity for cyanide ion over other anions such as Cl{sup −}, Br{sup −}, F{sup −}, I{sup −}, IO{sub 3}{sup −}, ClO{sub 4}{sup −}, BrO{sub 3}{sup −}, CO{sub 3}{sup 2−}, NO{sub 2}{sup −}, NO{sub 3}{sup −}, SO{sub 4}{sup 2−}, S{sub 2}O{sub 4}{sup 2−}, C{sub 2}O{sub 4}{sup 2−}, SCN{sup −}, N{sub 3}{sup −}, citrate and tartarate with negligible influences on the cyanide detection by fluorescence spectroscopy. - Highlights: • Preparation of functionalized ZnS quantum dots in aqueous media • Highly selective quantum dot based luminescent probe for determination of cyanide • Fast and sensitive determination of hazardous CN{sup −} by fluorescence quenching.

  6. Fluorescence Stability of Mercaptopropionic Acid Capped Cadmium Telluride Quantum Dots in Various Biochemical Buffers.

    Science.gov (United States)

    Borse, Vivek; Kashikar, Adisha; Srivastava, Rohit

    2018-04-01

    Quantum dots are the semiconductor nanocrystals having unique optical and electronic properties. Quantum dots are category of fluorescent labels utilized for biological tagging, biosensing, bioassays, bioimaging and in vivo imaging as they exhibit very small size, signal brightness, photostability, tuning of light emission range, longer photoluminescence decay time as compared to organic dyes. In this work, we have synthesized and characterized mercaptopropionic acid capped cadmium telluride quantum dots (MPA-CdTe QDs) using hydrothermal method. The study further reports fluorescence intensity stability of quantum dots suspended in different buffers of varying concentration (1-100 mM), stored at various photophysical conditions. Fluorescence intensity values were reduced with increase in buffer concentration. When the samples were stored at room temperature in ambient light condition the quantum dots suspended in different buffers lost the fluorescence intensity after day 15 (except TRIS II). Fluorescence intensity values were found stable for more than 30 days when the samples were stored in dark condition. Samples stored in refrigerator displayed modest fluorescence intensity even after 300 days of storage. Thus, storage of MPA-CdTe QDs in refrigerator may be the suitable choice to maintain its fluorescence stability for longer time for further application.

  7. Novel aspects of application of cadmium telluride quantum dots nanostructures in radiation oncology

    Energy Technology Data Exchange (ETDEWEB)

    Fazaeli, Yousef; Feizi, Shahzad [Nuclear Science and Technology Research Institute (NSTRI), Radiation Application Research School, Karaj (Iran, Islamic Republic of); Zare, Hakimeh; Karimi, Shokufeh [Yazd University, Department of Physics, Yazd (Iran, Islamic Republic of); Rahighi, Reza [Sharif University of Technology, Department of Physics, Tehran (Iran, Islamic Republic of)

    2017-08-15

    In the last two decades, quantum dots nanomaterials have garnered a great deal of scientific interest because of their unique properties. Quantum dots (QDs) are inorganic fluorescent nanocrystals in the size range between 1 and 20 nm. Due to their structural properties, they possess distinctive properties and behave in different way from crystals in macro scale, in many branches of human life. Cadmium telluride quantum dots (CdTe QDs) were labeled with {sup 68}Ga radio nuclide for fast in vivo targeting and coincidence imaging of tumors. Using instant paper chromatography, the physicochemical properties of the Cadmium telluride quantum dots labeled with {sup 68}Ga NPs ({sup 68}Ga rate at CdTe QDs) were found high enough stable in organic phases, e.g., a human serum, to be reliably used in bioapplications. In vivo biodistribution of the {sup 68}Ga rate at CdTe QDs nanoconposite was investigated in rats bearing fibro sarcoma tumor after various post-injection periods of time. The {sup 68}Ga NPs exhibited a rapid as well as high tumor uptake in a very short period of time (less than 10 min), resulting in an efficient tumor targeting/imaging agent. Meantime, the low lipophilicity of the {sup 68}Ga NPs caused to their fast excretion throughout the body by kidneys (as also confirmed by the urinary tract). Because of the short half-life of {sup 68}Ga radionuclide, the {sup 68}Ga rate at CdTe QDs with an excellent tumor targeting/imaging and fast washing out from the body can be suggested as one of the most effective and promising nanomaterials in nanotechnology-based cancer diagnosis and therapy. (orig.)

  8. Novel aspects of application of cadmium telluride quantum dots nanostructures in radiation oncology

    Science.gov (United States)

    Fazaeli, Yousef; Zare, Hakimeh; Karimi, Shokufeh; Rahighi, Reza; Feizi, Shahzad

    2017-08-01

    In the last two decades, quantum dots nanomaterials have garnered a great deal of scientific interest because of their unique properties. Quantum dots (QDs) are inorganic fluorescent nanocrystals in the size range between 1 and 20 nm. Due to their structural properties, they possess distinctive properties and behave in different way from crystals in macro scale, in many branches of human life. Cadmium telluride quantum dots (CdTe QDs) were labeled with 68Ga radio nuclide for fast in vivo targeting and coincidence imaging of tumors. Using instant paper chromatography, the physicochemical properties of the Cadmium telluride quantum dots labeled with 68Ga NPs (68Ga@ CdTe QDs) were found high enough stable in organic phases, e.g., a human serum, to be reliably used in bioapplications. In vivo biodistribution of the 68Ga@ CdTe QDs nanoconposite was investigated in rats bearing fibro sarcoma tumor after various post-injection periods of time. The 68Ga NPs exhibited a rapid as well as high tumor uptake in a very short period of time (less than 10 min), resulting in an efficient tumor targeting/imaging agent. Meantime, the low lipophilicity of the 68Ga NPs caused to their fast excretion throughout the body by kidneys (as also confirmed by the urinary tract). Because of the short half-life of 68Ga radionuclide, the 68Ga@ CdTe QDs with an excellent tumor targeting/imaging and fast washing out from the body can be suggested as one of the most effective and promising nanomaterials in nanotechnology-based cancer diagnosis and therapy.

  9. Synthesis of Water-Soluble Antimony Sulfide Quantum Dots and Their Photoelectric Properties.

    Science.gov (United States)

    Zhu, Jiang; Yan, Xuelian; Cheng, Jiang

    2018-01-15

    Antimony sulfide (Sb 2 S 3 ) has been applied in photoelectric devices for a long time. However, there was lack of information about Sb 2 S 3 quantum dots (QDs) because of the synthesis difficulties. To fill this vacancy, water-soluble Sb 2 S 3 QDs were prepared by hot injection using hexadecyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) mixture as anionic-cationic surfactant, alkanol amide (DEA) as stabilizer, and ethylenediaminetetraacetic acid (EDTA) as dispersant. Photoelectric properties including absorbing and emission were characterized by UV-Vis-IR spectrophotometer and photoluminescence (PL) spectroscopic technique. An intensive PL emission at 880 nm was found, indicating Sb 2 S 3 QDs have good prospects in near-infrared LED and near-infrared laser application. Sb 2 S 3 QD thin films were prepared by self-assembly growth and then annealed in argon or selenium vapor. Their band gaps (E g s) were calculated according to transmittance spectra. The E g of Sb 2 S 3 QD thin film has been found to be tunable from 1.82 to 1.09 eV via annealing or selenylation, demonstrating the good prospects in photovoltaic application.

  10. Achieving copper sulfide leaf like nanostructure electrode for high performance supercapacitor and quantum-dot sensitized solar cells

    Science.gov (United States)

    Durga, Ikkurthi Kanaka; Rao, S. Srinivasa; Reddy, Araveeti Eswar; Gopi, Chandu V. V. M.; Kim, Hee-Je

    2018-03-01

    Copper sulfide is an important multifunctional semiconductor that has attracted considerable attention owing to its outstanding properties and multiple applications, such as energy storage and electrochemical energy conversion. This paper describes a cost-effective and simple low-temperature solution approach to the preparation of copper sulfide for supercapacitors (SCs) and quantum-dot sensitized solar cells (QDSSCs). X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy confirmed that the nickel foam with a coriander leaf like nanostructure had been coated successfully with copper sulfide. As an electrode material for SCs, the CC-3 h showed excellent specific capacitance (5029.28 at 4 A g-1), energy density (169.73 W h kg-1), and superior cycling durability with 107% retention after 2000 cycles. Interestingly, the QDSSCs equipped with CC-2 h and CC-3 h counter electrodes (CEs) exhibited a maximum power conversion efficiency of 2.52% and 3.48%, respectively. The improved performance of the CC-3 h electrode was attributed mainly to the large surface area (which could contribute sufficient electroactive species), good conductivity, and high electrocatalytic activity. Overall, this work delivers novel insights into the use of copper sulfide and offers an important guidelines for the fabrication of next level energy storage and conversion devices.

  11. Synthesis and structural characterization of magnetic cadmium sulfide-cobalt ferrite nanocomposite, and study of its activity for dyes degradation under ultrasound

    Science.gov (United States)

    Farhadi, Saeed; Siadatnasab, Firouzeh

    2016-11-01

    Cadmium sulfide-cobalt ferrite (CdS/CFO) nanocomposite was easily synthesized by one-step hydrothermal decomposition of cadmium diethyldithiocarbamate complex on the CoFe2O4 nanoparticles at 200 °C. Spectroscopic techniques of powder X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), UV-visible spectroscopy, field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), Brunauer-Emmett-Teller (BET), and magnetic measurements were applied for characterizing the structure and morphology of the product. The results of FT-IR, XRD and EDX indicated that the CdS/CFO was highly pure. SEM and TEM results revealed that the CdS/CFO nanocomposite was formed from nearly uniform and sphere-like nanoparticles with the size of approximately 20 nm. The UV-vis absorption spectrum of the CdS/CFO nanocomposite showed the band gap of 2.21 eV, which made it suitable for sono-/photo catalytic purposes. By using the obtained CdS/CFO nanocomposite, an ultrasound-assisted advanced oxidation process (AOP) has been developed for catalytic degradation of methylene blue (MB), Rhodamine B (RhB), and methyl orange (MO)) in the presence of H2O2 as a green oxidant. CdS/CFO nanocomposite exhibited excellent sonocatalytic activity, so that, dyes were completely degraded in less than 10 min. The influences of crucial factors such as the H2O2 amount and catalyst dosage on the degradation efficiency were evaluated. The as-prepared CdS/CFO nanocomposite exhibited higher catalytic activity than pure CdS nanoparticles. Moreover, the magnetic property of CoFe2O4 made the nanocomposite recyclable.

  12. Photo-induced surface modification to improve the performance of lead sulfide quantum dot solar cell.

    Science.gov (United States)

    Tulsani, Srikanth Reddy; Rath, Arup Kumar

    2018-07-15

    The solution-processed quantum dot (QD) solar cell technology has seen significant advancements in recent past to emerge as a potential contender for the next generation photovoltaic technology. In the development of high performance QD solar cell, the surface ligand chemistry has played the important role in controlling the doping type and doping density of QD solids. For instance, lead sulfide (PbS) QDs which is at the forefront of QD solar cell technology, can be made n-type or p-type respectively by using iodine or thiol as the surfactant. The advancements in surface ligand chemistry enable the formation of p-n homojunction of PbS QDs layers to attain high solar cell performances. It is shown here, however, that poor Fermi level alignment of thiol passivated p-type PbS QD hole transport layer with the n-type PbS QD light absorbing layer has rendered the photovoltaic devices from realizing their full potential. Here we develop a control surface oxidation technique using facile ultraviolet ozone treatment to increase the p-doping density in a controlled fashion for the thiol passivated PbS QD layer. This subtle surface modification tunes the Fermi energy level of the hole transport layer to deeper values to facilitate the carrier extraction and voltage generation in photovoltaic devices. In photovoltaic devices, the ultraviolet ozone treatment resulted in the average gain of 18% in the power conversion efficiency with the highest recorded efficiency of 8.98%. Copyright © 2018 Elsevier Inc. All rights reserved.

  13. Eddy covariance carbonyl sulfide flux measurements with a quantum cascade laser absorption spectrometer

    Directory of Open Access Journals (Sweden)

    K. Gerdel

    2017-09-01

    Full Text Available The trace gas carbonyl sulfide (COS has lately received growing interest from the eddy covariance (EC community due to its potential to serve as an independent approach for constraining gross primary production and canopy stomatal conductance. Thanks to recent developments of fast-response high-precision trace gas analysers (e.g. quantum cascade laser absorption spectrometers, QCLAS, a handful of EC COS flux measurements have been published since 2013. To date, however, a thorough methodological characterisation of QCLAS with regard to the requirements of the EC technique and the necessary processing steps has not been conducted. The objective of this study is to present a detailed characterisation of the COS measurement with the Aerodyne QCLAS in the context of the EC technique and to recommend best EC processing practices for those measurements. Data were collected from May to October 2015 at a temperate mountain grassland in Tyrol, Austria. Analysis of the Allan variance of high-frequency concentration measurements revealed the occurrence of sensor drift under field conditions after an averaging time of around 50 s. We thus explored the use of two high-pass filtering approaches (linear detrending and recursive filtering as opposed to block averaging and linear interpolation of regular background measurements for covariance computation. Experimental low-pass filtering correction factors were derived from a detailed cospectral analysis. The CO2 and H2O flux measurements obtained with the QCLAS were compared with those obtained with a closed-path infrared gas analyser. Overall, our results suggest small, but systematic differences between the various high-pass filtering scenarios with regard to the fraction of data retained in the quality control and flux magnitudes. When COS and CO2 fluxes are combined in the ecosystem relative uptake rate, systematic differences between the high-pass filtering scenarios largely cancel out, suggesting that

  14. Toxicity of quantum dots and cadmium to rainbow trout (Oncorhynchus mykiss in early ontogenesis

    Directory of Open Access Journals (Sweden)

    Živilė Cibulskaitė

    2015-11-01

    Full Text Available The aim of the study was to investigate toxic effects of CdSe/ZnS-COOH quantum dots (QD and cadmium (Cd on biological parameters of rainbow trout (Oncorhychus mykiss in its early stages of development (embryos and larvae. It was found that short-term (24-, 96-hour exposure to sublethal concentrations of QD and Cd increased mortality of embryos and larvae, disturbed function of the cardio-respiratory system (gill ventilation frequency, heart rate and affected behavioural responses (individuals making nests in rainbow trout larvae. The results indicated that toxic effects of QD and Cd on rainbow trout larvae depended on the type of chemical substance, affected stage of development and exposure duration. Comparative studies of the effects of QD and Cd on rainbow trout in early stages of development showed that larvae were more sensitive to Cd and QD as compared to embryos. It was suggested that the chorion envelopes of eggs surround and protect the embryo from QD and Cd. Cadmium was more toxic to larvae than QD. Longer exposure (96-hour of QD and Cd induced more remarkable changes in test-parameters. This original study requires more investigations evaluating the mechanism of toxicity of QD to fish.

  15. Comparison of cytotoxicity and expression of metal regulatory genes in zebrafish (Danio rerio) liver cells exposed to cadmium sulfate, zinc sulfate and quantum dots.

    Science.gov (United States)

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

    2013-10-01

    Recent advances in the ability to manufacture and manipulate materials at the nanometer scale have led to increased production and use of many types of nanoparticles. Quantum dots (QDs) are small, fluorescent nanoparticles composed of a core of semiconductor material (e.g. cadmium selenide, zinc sulfide) and shells or dopants of other elements. Particle core composition, size, shell, and surface chemistry have all been found to influence toxicity in cells. The aim of this study was to compare the toxicities of ionic cadmium (Cd) and zinc (Zn) and Cd- and Zn-containing QDs in zebrafish liver cells (ZFL). As expected, Cd(2+) was more toxic than Zn(2+), and the general trend of IC50-24 h values of QDs was determined to be CdTe InP/ZnS, suggesting that ZnS-shelled CdSe/ZnS QDs were more cytocompatible than bare core CdTe crystals. Smaller QDs showed greater toxicity than larger QDs. Isolated mRNA from these exposures was used to measure the expression of metal response genes including metallothionein (MT), metal response element-binding transcription factor (MTF-1), divalent metal transporter (DMT-1), zrt and irt like protein (ZIP-1) and the zinc transporter, ZnT-1. CdTe exposure induced expression of these genes in a dose dependent manner similar to that of CdSO4 exposure. However, CdSe/ZnS and InP/ZnS altered gene expression of metal homeostasis genes in a manner different from that of the corresponding Cd or Zn salts. This implies that ZnS shells reduce QD toxicity attributed to the release of Cd(2+), but do not eliminate toxic effects caused by the nanoparticles themselves.

  16. Cytotoxicity of cadmium-free quantum dots and their use in cell bioimaging.

    Science.gov (United States)

    Soenen, Stefaan J; Manshian, Bella B; Aubert, Tangi; Himmelreich, Uwe; Demeester, Jo; De Smedt, Stefaan C; Hens, Zeger; Braeckmans, Kevin

    2014-06-16

    The use of quantum dots (QDots) as bright and photostable probes for long-term fluorescence imaging is gaining more interest. Thus far, (pre)clinical use of QDots remains limited, which is primarily caused by the potential toxicity of QDots. Most QDots consist of Cd2+ ions, which are known to cause high levels of toxicity. In order to overcome this problem, several strategies have been tested, such as the generation of cadmium-free QDots. In the present study, two types of cadmium-free QDots, composed of ZnSe/ZnS (QDotZnSe) and InP/ZnS (QDotInP), were studied with respect to their cytotoxicity and cellular uptake in a variety of cell types. A multiparametric cytotoxicity approach is used, where the QDots are studied with respect to cell viability, oxidative stress, cell morphology, stem cell differentiation, and neurite outgrowth. The data reveal slight differences in uptake levels for both types of QDots (maximal for QDotZnSe), but clear differences in cytotoxicity and cell functionality effects exist, with highest toxicity for QDotZnSe. Differences between cell types and between both types of QDots can be explained by the intrinsic sensitivity of certain cell types and chemical composition of the QDots. At concentrations at which no toxic effects can be observed, the functionality of the QDots for fluorescence cell visualization is evaluated, revealing that the higher brightness of QDotZnSe overcomes most of the toxicity issues compared to that of QDotInP. Comparing the results obtained with common Cd2+-containing QDots tested under identical conditions, the importance of particle functionality is demonstrated, revealing that cadmium-free QDots tested in this study are not significantly better than Cd2+-containing QDots for long-term cell imaging and that more work needs to be performed in optimizing the brightness and surface chemistry of cadmium-free QDots for them to replace currently used Cd2+-containing QDots.

  17. Quantum cascade laser-based analyzer for hydrogen sulfide detection at sub-parts-per-million levels

    Science.gov (United States)

    Nikodem, Michal; Krzempek, Karol; Stachowiak, Dorota; Wysocki, Gerard

    2018-01-01

    Due to its high toxicity, monitoring of hydrogen sulfide (H2S) concentration is essential in many industrial sites (such as natural gas extraction sites, petroleum refineries, geothermal power plants, or waste water treatment facilities), which require sub-parts-per-million sensitivities. We report on a quantum cascade laser-based spectroscopic system for detection of H2S in the midinfrared at ˜7.2 μm. We present a sensor design utilizing Herriott multipass cell and a wavelength modulation spectroscopy to achieve a detection limit of 140 parts per billion for 1-s integration time.

  18. Improvement of the characteristics of chemical bath deposition-cadmium sulfide films deposited on an O{sub 2} plasma-treated polyethylene terephthalate substrate

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Donggun [Department of Electronic Engineering, Korea National University of Transportation, Chungju-si, Chungcheongbuk-do 380-702 (Korea, Republic of); Lee, Jaehyeong [School of Electronic and Electrical Engineering, Sungkyunkwan University 300, Cheoncheon-dong, Jangan-gu, Sunwon, Kyeonggi-do, 440-746 (Korea, Republic of); Song, Woochang, E-mail: wcsong@kangwon.ac.kr [Department of Electrical Engineering, Kangwon National University, Samcheok-si, Gangwon-do 245-711 (Korea, Republic of)

    2013-11-01

    We prepared cadmium sulfide (CdS) films on a polyethylene terephthalate (PET) substrate by a chemical bath deposition (CBD) technique. To improve the adhesion between the CdS film and the PET substrate, the substrate was pre-treated with an O{sub 2} plasma by an inductively coupled plasma. The surface characterizations of the pre-treated PET substrate were analyzed by a contact angle measurement and atomic force microscopy. The results showed that that O{sub 2} plasma-treated PET films had more hydrophilic surface. The hydrophilic property of the substrate is one of the important factors when a film is prepared by CBD. The structural and the optical properties of the CdS films, deposited on PET substrates, were analyzed by using a scanning electron microscope, X-ray diffraction and a UV–visible spectrophotometer. The CdS films were formed on a compact and granular structure. The optical transmittance was also improved. Therefore, the O{sub 2} plasma treatment of a PET surface is an effective method of preparing CdS films deposited on substrates by CBD. - Highlights: • Chemical bath deposition of CdS film for flexible solar cells • O{sub 2} plasma treatment improved adhesion between the CdS and polymer substrate • Identification of best fabrication condition of CdS window layers for flexible solar cells.

  19. Reduced Graphene Oxide-Cadmium Zinc Sulfide Nanocomposite with Controlled Band Gap for Large-Area Thin-Film Optoelectronic Device Application

    Science.gov (United States)

    Ibrahim, Sk; Chakraborty, Koushik; Pal, Tanusri; Ghosh, Surajit

    2017-12-01

    Herein, we report the one pot single step solvothermal synthesis of reduced grapheme oxide-cadmium zinc sulfide (RGO-Cd0.5Zn0.5S) composite. The reduction in graphene oxide (GO), synthesis of Cd0.5Zn0.5S (mentioned as CdZnS in the text) nanorod and decoration of CdZnS nanorods onto RGO sheet were done simultaneously. The structural, morphological and optical properties were studied thoroughly by different techniques, such as XRD, TEM, UV-Vis and PL. The PL intensity of CdZnS nanorods quenches significantly after the attachment of RGO, which confirms photoinduced charge transformation from CdZnS nanorods to RGO sheet through the interface of RGO-CdZnS. An excellent photocurrent generation in RGO-CdZnS thin-film device has been observed under simulated solar light irradiation. The photocurrent as well as photosensitivity increases linearly with the solar light intensity for all the composites. Our study establishes that the synergistic effect of RGO and CdZnS in the composite is capable of getting promising applications in the field of optoelectronic devising.

  20. Synthesis, structural and property studies of Ni doped cadmium sulphide quantum dots stabilized in DETA matrix

    International Nuclear Information System (INIS)

    Mercy, A.; Jesper Anandhi, A.; Sakthi Murugesan, K.; Jayavel, R.; Kanagadurai, R.; Milton Boaz, B.

    2014-01-01

    Highlights: • Ni doped CdS nanoparticles are synthesized by chemical precipitation method. • X-ray diffractogram confirms the formation of CdS with dopant. • FTIR spectrum reveals that the nanosamples are encapsulated by DETA. • The UV-VIS absorption spectra shows strong blue shift. - Abstract: Pure and Nickel doped cadmium sulphide nanoparticles at pH value 10 with three different concentrations have been synthesized by chemical precipitation method. Diethylene triamine was used as stabilizing agent to control the particle size as quantum dots without any agglomeration. The synthesized samples were characterized with X-ray diffraction (XRD), High resolution scanning electron microscopy (HRSEM), Energy dispersive X-ray analysis (EDAX), Transmission electron microscopy (TEM), Ultraviolet–Visible absorption spectroscopy (UV–VIS), Fourier transform infrared (FTIR) spectroscopy and photoluminescence (PL) studies. The nano crystalline nature of the as prepared samples is confirmed using XRD analysis. The average size of Ni doped cadmium sulphide nanoparticles calculated from Debye Scherer formula was of the order of 1.5–3 nm and that of pure CdS nanoparticles was of the order of 6–7 nm. The same value of the particle size was confirmed by using Williamson Hall plot as well as Henglein’s formula. X-ray peak broadening analysis was carried out using Williamson–Hall plot. The surface morphology studies of the sample using HRSEM images show the formation of nanoclusters and the EDAX spectra confirms the presence of cadmium sulphide and nickel elements in the sample. TEM images establish the stabilization of CdS nanoparticles in DETA. The UV–VIS absorption spectra of the sample show blue shift in the absorption region due to the quantum confinement effect. FTIR studies have been carried out to establish the presence of bonding by capping agent in the Ni doped samples. The synthesized samples show photoluminescence in the spectral region from 350 to 550

  1. Inhibition of autophagy overcomes the nanotoxicity elicited by cadmium-based quantum dots.

    Science.gov (United States)

    Fan, Jiajun; Sun, Yun; Wang, Shaofei; Li, Yubin; Zeng, Xian; Cao, Zhonglian; Yang, Ping; Song, Ping; Wang, Ziyu; Xian, Zongshu; Gao, Hongjian; Chen, Qicheng; Cui, Daxiang; Ju, Dianwen

    2016-02-01

    Cadmium-based quantum dots (QDs) have shown their values in disease diagnosis, cellular and molecular tracking, small-animal imaging, and therapeutic drug delivery. However, the potential safety problems of QDs, mainly due to their nanotoxicities by unclear mechanisms, have greatly limited its applications. To reverse this situation, we investigated the underlying biological mechanisms of the toxicity of Quantum Dots CdTe/CdS 655 (QDs 655) in this work. QDs 655 was found to elicit nanotoxicity in vitro and in vivo. During the process, autophagy was activated, which was characterized by three main stages of autophagic flux including formation of autophagosomes, lysosomes fused with autophagosomes, and degradation of autophagosomes by lysosomes. Furthermore, the autophagic cell death was demonstrated in vitro under QDs 655 treatment while inhibition of autophagy by pharmacological inhibitors or genetic approaches could attenuate the toxicity induced by QDs 655 in vitro and in vivo. These results indicated that autophagic flux and autophagic cell death were triggered by QDs 655, which elucidated the critical role of autophagy in QDs 655 induced toxicity. Our data may suggest the approach to overcome the toxicity of QDs and other nanoparticles by autophagy inhibition. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. In vivo toxicity assessment of non-cadmium quantum dots in BALB/c mice.

    Science.gov (United States)

    Lin, Guimiao; Ouyang, Qingling; Hu, Rui; Ding, Zhangchi; Tian, Jinglin; Yin, Feng; Xu, Gaixia; Chen, Qiang; Wang, Xiaomei; Yong, Ken-Tye

    2015-02-01

    Along with widespread usage of QDs in electronic and biomedical industries, the likelihood of QDs exposure to the environment and humans is deemed to occur when the QD products are degraded or handled as waste for processing. To date, there are very few toxicological reports available in the literature for non-cadmium QDs in animal models. In this work, we studied the long term in vivo toxicity of InP/ZnS QDs in BALB/c mice. The biodistribution, body weight, hematology, blood biochemistry, and organ histology were determined at a very high dosage (25 mg/kg) of InP/ZnS QDs over 84 days period. Our results manifested that the QDs formulation did not result in observable toxicity in vivo within the evaluation period, thereby suggesting that the InP/ZnS QDs can be utilized as optical probes or nanocarrier for selected in vivo biological applications when an optimized dosage is employed. This study investigated the toxicity of quantum dots in BALB/c mice, and concluded that no organotoxicity was detectable despite of using high concentration of InP/ZnS quantum dots with prolonged exposure of 3 months. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Solar cells with PbS quantum dot sensitized TiO2-multiwalled carbon nanotube composites, sulfide-titania gel and tin sulfide coated C-fabric.

    Science.gov (United States)

    Kokal, Ramesh K; Deepa, Melepurath; Kalluri, Ankarao; Singh, Shrishti; Macwan, Isaac; Patra, Prabir K; Gilarde, Jeff

    2017-10-04

    Novel approaches to boost quantum dot solar cell (QDSC) efficiencies are in demand. Herein, three strategies are used: (i) a hydrothermally synthesized TiO 2 -multiwalled carbon nanotube (MWCNT) composite instead of conventional TiO 2 , (ii) a counter electrode (CE) that has not been applied to QDSCs until now, namely, tin sulfide (SnS) nanoparticles (NPs) coated over a conductive carbon (C)-fabric, and (iii) a quasi-solid-state gel electrolyte composed of S 2- , an inert polymer and TiO 2 nanoparticles as opposed to a polysulfide solution based hole transport layer. MWCNTs by virtue of their high electrical conductivity and suitably positioned Fermi level (below the conduction bands of TiO 2 and PbS) allow fast photogenerated electron injection into the external circuit, and this is confirmed by a higher efficiency of 6.3% achieved for a TiO 2 -MWCNT/PbS/ZnS based (champion) cell, compared to the corresponding TiO 2 /PbS/ZnS based cell (4.45%). Nanoscale current map analysis of TiO 2 and TiO 2 -MWCNTs reveals the presence of narrowly spaced highly conducting domains in the latter, which equips it with an average current carrying capability greater by a few orders of magnitude. Electron transport and recombination resistances are lower and higher respectively for the TiO 2 -MWCNT/PbS/ZnS cell relative to the TiO 2 /PbS/ZnS cell, thus leading to a high performance cell. The efficacy of SnS/C-fabric as a CE is confirmed from the higher efficiency achieved in cells with this CE compared to the C-fabric based cells. Lower charge transfer and diffusional resistances, slower photovoltage decay, high electrical conductance and lower redox potential impart high catalytic activity to the SnS/C-fabric assembly for sulfide reduction and thus endow the TiO 2 -MWCNT/PbS/ZnS cell with a high open circuit voltage (0.9 V) and a large short circuit current density (∼20 mA cm -2 ). This study attempts to unravel how simple strategies can amplify QDSC performances.

  4. Covalent attachment of thionine onto gold electrode modified with cadmium sulfide nanoparticles: Improvement of electrocatalytic and photelectrocatalytic reduction of hydrogen peroxide

    International Nuclear Information System (INIS)

    Salimi, Abdollah; Rahmatpanah, Rojzin; Hallaj, Rahman; Roushani, Mahmoud

    2013-01-01

    A newly developed strategy based on gold (Au) electrode modified with cadmium sulfide nanoparticles (CdSnp) and thionine (Th) was proposed toward electrocatalytic and photoelectrocatalytic hydrogen peroxide (H 2 O 2 ) reduction. At first, a thin film of CdS nanoparticles was electrodeposited onto Au electrode. Then, the CdS/Au electrode was modified with mercaptoacetic acid (MAA), which not only acts as a stabilizing agent to prevent the chalcogenide CdS nanocrystals from aggregation but also as a linker for subsequent attachment of Th onto the CdS nanoparticles. The effective covalent immobilization of Th was achieved through amide bond formation reaction between -NH 2 groups of Th and -COOH groups of MAA, using dicyclohexylcarbodiimide (DCC) as condensation agent. The Au/CdS/Th modified electrode showed a well-defined redox couple with surface confined characteristics at wide pH range (2–12). The heterogeneous electron transfer rate constant (k s ) and the surface coverage of immobilized Th on the modified electrode was obtained as 0.12 s −1 and 4.35 × 10 −9 mole cm −2 , respectively. The electrocatalytic activity and stability of the modified electrode toward hydrogen peroxide reduction was investigated and it was found that the Au/CdS/Th electrode illustrates excellent electrocatalytic activity toward H 2 O 2 reduction at reduced overpotential. The detection limit, sensitivity and catalytic rate constant (k cat ) of the modified electrode toward H 2 O 2 were 55 nM, 3.4 μA μM −1 cm −2 and 3.75 (±0.1) × 10 3 M −1 s −1 , respectively, at linear concentration range up to 10 mM. Upon light irradiation, about two-fold improvements were attained in sensitivity and detection limit of the modified electrode toward H 2 O 2 electrocatalytic determination

  5. Cytotoxicity of cadmium-containing quantum dots based on a study using a microfluidic chip

    International Nuclear Information System (INIS)

    Zheng Xiannuo; Weng Lixing; Tian Jing; Wang Lianhui; Wu Lei; Jin Qinghui; Zhao Jianlong

    2012-01-01

    There is a lack of reliable nanotoxicity assays available for monitoring and quantifying multiple cellular events in cultured cells. In this study, we used a microfluidic chip to systematically investigate the cytotoxicity of three kinds of well-characterized cadmium-containing quantum dots (QDs) with the same core but different shell structures, including CdTe core QDs, CdTe/CdS core–shell QDs, and CdTe/CdS/ZnS core–shell–shell QDs, in HEK293 cells. Using the microfluidic chip combined with fluorescence microscopy, multiple QD-induced cellular events including cell morphology, viability, proliferation, and QD uptake were simultaneously analysed. The three kinds of QDs showed significantly different cytotoxicities. The CdTe QDs, which are highly toxic to HEK293 cells, resulted in remarkable cellular and nuclear morphological changes, a dose-dependent decrease in cell viability, and strong inhibition of cell proliferation; the CdTe/CdS QDs were moderately toxic but did not significantly affect the proliferation of HEK293 cells; while the CdTe/CdS/ZnS QDs had no detectable influence on cytotoxicity with respect to cell morphology, viability, and proliferation. Our data indicated that QD cytotoxicity was closely related to their surface structures and specific physicochemical properties. This study also demonstrated that the microfluidic chip could serve as a powerful tool to systematically evaluate the cytotoxicity of nanoparticles in multiple cellular events. (paper)

  6. Cytotoxicity of cadmium-containing quantum dots based on a study using a microfluidic chip

    Science.gov (United States)

    Zheng, Xiannuo; Tian, Jing; Weng, Lixing; Wu, Lei; Jin, Qinghui; Zhao, Jianlong; Wang, Lianhui

    2012-02-01

    There is a lack of reliable nanotoxicity assays available for monitoring and quantifying multiple cellular events in cultured cells. In this study, we used a microfluidic chip to systematically investigate the cytotoxicity of three kinds of well-characterized cadmium-containing quantum dots (QDs) with the same core but different shell structures, including CdTe core QDs, CdTe/CdS core-shell QDs, and CdTe/CdS/ZnS core-shell-shell QDs, in HEK293 cells. Using the microfluidic chip combined with fluorescence microscopy, multiple QD-induced cellular events including cell morphology, viability, proliferation, and QD uptake were simultaneously analysed. The three kinds of QDs showed significantly different cytotoxicities. The CdTe QDs, which are highly toxic to HEK293 cells, resulted in remarkable cellular and nuclear morphological changes, a dose-dependent decrease in cell viability, and strong inhibition of cell proliferation; the CdTe/CdS QDs were moderately toxic but did not significantly affect the proliferation of HEK293 cells; while the CdTe/CdS/ZnS QDs had no detectable influence on cytotoxicity with respect to cell morphology, viability, and proliferation. Our data indicated that QD cytotoxicity was closely related to their surface structures and specific physicochemical properties. This study also demonstrated that the microfluidic chip could serve as a powerful tool to systematically evaluate the cytotoxicity of nanoparticles in multiple cellular events.

  7. Fluorescently labelled multiplex lateral flow immunoassay based on cadmium-free quantum dots.

    Science.gov (United States)

    Beloglazova, Natalia V; Sobolev, Aleksander M; Tessier, Mickael D; Hens, Zeger; Goryacheva, Irina Yu; De Saeger, Sarah

    2017-03-01

    A sensitive tool for simultaneous qualitative detection of two mycotoxins based on use of non-cadmium quantum dots (QDs) is presented for the first time. QDs have proven themselves as promising fluorescent labels for biolabeling and chemical analysis. With an increasing global tendency to regulate and limit the use of hazardous elements, indium phosphide (InP) QDs are highlighted as environmentally-friendly alternatives to the highly efficient and well-studied, but potentially toxic Cd- and Pb-based QDs. Here, we developed water-soluble InP QDs-based fluorescent nanostructures. They consisted of core/shell InP/ZnS QDs enrobed in a silica shell that allowed the water solubility (QD@SiO 2 ). Then we applied the QD@SiO 2 as novel, silica shell-encapsulated fluorescent labels in immunoassays for rapid multiplexed screening. Two mycotoxins, zearalenone and deoxynivalenol, were simultaneously detected in maize and wheat, since the two QD@SiO 2 labelled conjugates emit at two different, individually detectable wavelengths. The cutoff values for the simultaneous determination were 50 and 500μgkg -1 for zearalenone and deoxynivalenol, respectively, in both maize and wheat. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was used to confirm the result. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Toxicological impact of cadmium-based quantum dots towards aquatic biota: Effect of natural sunlight exposure

    Energy Technology Data Exchange (ETDEWEB)

    Silva, B.F. [Department of Biology, Faculty of Science, University of Porto, Rua do Campo Alegre, 4169-007 Porto (Portugal); CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, Rua dos Bragas, 289, 4050-123 Porto (Portugal); Andreani, T. [Centro de Investigação em Química da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal); Department of Chemistry and Biochemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 4169-007 Porto (Portugal); CITAB − Centre for Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-os-Montes e Alto Douro, UTAD, Vila Real (Portugal); Gavina, A., E-mail: anacsgavina@gmail.com [Department of Biology, Faculty of Science, University of Porto, Rua do Campo Alegre, 4169-007 Porto (Portugal); CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, Rua dos Bragas, 289, 4050-123 Porto (Portugal); Vieira, M.N. [Department of Biology, Faculty of Science, University of Porto, Rua do Campo Alegre, 4169-007 Porto (Portugal); CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, Rua dos Bragas, 289, 4050-123 Porto (Portugal); Pereira, C.M. [Centro de Investigação em Química da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal); Department of Chemistry and Biochemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 4169-007 Porto (Portugal); Rocha-Santos, T. [Department of Chemistry and Centre for Environmental and Marine Studies (CESAM), University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); and others

    2016-07-15

    Highlights: • Under sunlight exposure, all QDs form particle aggregates in the different media. • CdSeS/ZnS QDs showed lower toxic effects to V. fischeri before sunlight exposure. • Sunlight exposure decreased the toxicity of CdS 480 in all organisms. • Sunlight exposure increased the toxicity of CdS 380 QDs for D. magna. • Shell of QDs seemed to make them less harmful to aquatic organisms. - Abstract: Cadmium-based quantum dots (QDs) are increasingly applied in existent and emerging technologies, especially in biological applications due to their exceptional photophysical and functionalization properties. However, they are very toxic compounds due to the high reactive and toxic cadmium core. The present study aimed to determine the toxicity of three different QDs (CdS 380, CdS 480 and CdSeS/ZnS) before and after the exposure of suspensions to sunlight, in order to assess the effect of environmentally relevant irradiation levels in their toxicity, which will act after their release to the environment. Therefore, a battery of ecotoxicological tests was performed with organisms that cover different functional and trophic levels, such as Vibrio fischeri, Raphidocelis subcapitata, Chlorella vulgaris and Daphnia magna. The results showed that core-shell type QDs showed lower toxic effects to V. fischeri in comparison to core type QDs before sunlight exposure. However, after sunlight exposure, there was a decrease of CdS 380 and CdS 480 QD toxicity to bacterium. Also, after sunlight exposure, an effective decrease of CdSeS/ZnS and CdS 480 toxicity for D. magna and R. subcapitata, and an evident increase in CdS 380 QD toxicity, at least for D. magna, were observed. The results of this study suggest that sunlight exposure has an effect in the aggregation and precipitation reactions of larger QDs, causing the degradation of functional groups and formation of larger bulks which may be less prone to photo-oxidation due to their diminished surface area. The same

  9. Cadmium telluride quantum dots induce apoptosis in human breast cancer cell lines.

    Science.gov (United States)

    Naderi, Saeed; Zare, Hakimeh; Taghavinia, Nima; Irajizad, Azam; Aghaei, Mahmoud; Panjehpour, Mojtaba

    2018-05-01

    Semiconductor quantum dots (QDs), especially those containing cadmium, have undergone marked improvements and are now widely used nanomaterials in applicable biological fields. However, great concerns exist regarding their toxicity in biomedical applications. Because of the lack of sufficient data regarding the toxicity mechanism of QDs, this study aimed to evaluate the cytotoxicity of three types of QDs: CdTe QDs, high yield CdTe QDs, and CdTe/CdS core/shell QDs on two human breast cancer cell lines MDA-MB468 and MCF-7. The breast cancer cells were treated with different concentrations of QDs, and cell viability was evaluated via MTT assay. Hoechst staining was applied for observation of morphological changes due to apoptosis. Apoptotic DNA fragmentation was visualized by the agarose gel electrophoresis assay. Flow cytometric annexin V/propidium iodide (PI) measurement was used for apoptosis detection. A significant decrease in cell viability was observed after QDs treatment ( p < 0.05). Apoptotic bodies and chromatin condensation was observed by Hoechst staining. DNA fragmentation assay demonstrated a DNA ladder profile in the exposed cells and also annexin V/PI flow cytometry confirmed apoptosis in a dose-dependent manner. Our results revealed that CdTe, high yield CdTe, and CdTe/CdS core/shell QDs induce apoptosis in breast cancer cell lines in a dose-dependent manner. This study would help realizing the underlying cytotoxicity mechanism, at least partly, of CdTe QDs and may provide information for the development of nanotoxicology and safe use of biological applications of QDs.

  10. Inhibition of autophagy contributes to the toxicity of cadmium telluride quantum dots in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Fan J

    2016-07-01

    Full Text Available Junpeng Fan,1–4 Ming Shao,1–4 Lu Lai,3–5 Yi Liu,3–5 Zhixiong Xie1–4,6 1College of Life Sciences, Wuhan University, 2Hubei Provincial Cooperative Innovation Center of Industrial Fermentation,3State Key Laboratory of Virology, 4Key Laboratory of Analytical Chemistry for Biology and Medicine (MOE, 5College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 6School of Life Science and Technology, Hubei Engineering University, Xiaogan, People’s Republic of China Abstract: Cadmium telluride quantum dots (CdTe QDs are used as near-infrared probes in biologic and medical applications, but their cytological effects and mechanism of potential toxicity are still unclear. In this study, we evaluated the toxicity of CdTe QDs of different sizes and investigated their mechanism of toxicity in the yeast Saccharomyces cerevisiae. A growth inhibition assay revealed that orange-emitting CdTe (O-CdTe QDs (half inhibitory concentration [IC50] =59.44±12.02 nmol/L were more toxic than green-emitting CdTe QDs (IC50 =186.61±19.74 nmol/L to S. cerevisiae. Further studies on toxicity mechanisms using a transmission electron microscope and green fluorescent protein tagged Atg8 processing assay revealed that O-CdTe QDs could partially inhibit autophagy at a late stage, which differs from the results reported in mammalian cells. Moreover, autophagy inhibited at a late stage by O-CdTe QDs could be partially recovered by enhancing autophagy with rapamycin (an autophagy activator, combined with an increased number of living cells. These results indicate that inhibition of autophagy acts as a toxicity mechanism of CdTe QDs in S. cerevisiae. This work reports a novel toxicity mechanism of CdTe QDs in yeast and provides valuable information on the effect of CdTe QDs on the processes of living cells. Keywords: CdTe quantum dots, Saccharomyces cerevisiae, toxicity, autophagy

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

    Directory of Open Access Journals (Sweden)

    Laura Paesano

    2017-04-01

    Full Text Available 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. Physicochemical properties of hybrid graphene-lead sulfide quantum dots prepared by supercritical ethanol

    Science.gov (United States)

    Tavakoli, Mohammad Mahdi; Tayyebi, Ahmad; Simchi, Abdolreza; Aashuri, Hossein; Outokesh, Mohmmad; Fan, Zhiyong

    2015-01-01

    Recently, hybrid graphene-quantum dot systems have attracted increasing attention for the next-generation optoelectronic devices such as ultrafast photo-detectors and solar energy harvesting. In this paper, a novel, one-step, reproducible, and solution-processed method is introduced to prepare hybrid graphene-PbS colloids by employing supercritical ethanol. In the hybrid nanocomposite, PbS quantum dots ( 3 nm) are decorated on the reduced graphene oxide (rGO) nanosheets ( 1 nm thickness and less than 1 micron lengths). By employing X-ray photoelectron and Raman and infrared spectroscopy techniques, it is shown that the rGO nanosheets are bonded to PbS nanocrystals through carboxylic bonds. Passivation of {111} planes of PbS quantum dots with rGO nanosheets is demonstrated by employing density function theory. Quenching of the photoluminescence emission of PbS nanocrystals through coupling with graphene sheets is also shown. In order to illustrate that the developed preparation method does not impair the quantum efficiency of the PbS nanocrystals, the photovoltaic efficiency of solar cell device is reported and compared with oleic acid-capped PbS colloidal quantum dot solar cells. By employing the "Hall effect" measurement, it is shown that the carrier mobility is significantly increased (by two orders of magnitudes) in the presence of graphene nanosheets.

  13. Time-dependent toxicity of cadmium telluride quantum dots on liver and kidneys in mice: histopathological changes with elevated free cadmium ions and hydroxyl radicals

    Directory of Open Access Journals (Sweden)

    Wang M

    2016-05-01

    Full Text Available Mengmeng Wang,1,2,* Jilong Wang,1,2,* Hubo Sun,1,2 Sihai Han,3 Shuai Feng,1 Lu Shi,1 Peijun Meng,1,2 Jiayi Li,1,2 Peili Huang,1,2 Zhiwei Sun1,2 1Department of Toxicology and Sanitary Chemistry, School of Public Health, Capital Medical University, 2Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing, 3College of Food and Bioengineering, Henan University of Science and Technology, Luoyang, People’s Republic of China *These authors contributed equally to this work Abstract: A complete understanding of the toxicological behavior of quantum dots (QDs in vivo is of great importance and a prerequisite for their application in humans. In contrast with the numerous cytotoxicity studies investigating QDs, only a few in vivo studies of QDs have been reported, and the issue remains controversial. Our study aimed to understand QD-mediated toxicity across different time points and to explore the roles of free cadmium ions (Cd2+ and hydroxyl radicals (·OH in tissue damage. Male ICR mice were administered a single intravenous dose (1.5 µmol/kg of CdTe QDs, and liver and kidney function and morphology were subsequently examined at 1, 7, 14, and 28 days. Furthermore, ·OH production in the tissue was quantified by trapping ·OH with salicylic acid (SA as 2,3-dihydroxybenzoic acid (DHBA and detecting it using a high-performance liquid chromatography fluorescence method. We used the induction of tissue metallothionein levels and 2,3-DHBA:SA ratios as markers for elevated Cd2+ from the degradation of QDs and ·OH generation in the tissue, respectively. Our experimental results revealed that the QD-induced histopathological changes were time-dependent with elevated Cd2+ and ·OH, and could recover after a period of time. The Cd2+ and ·OH exhibited delayed effects in terms of histopathological abnormalities. Histological assessments performed at multiple time points might facilitate the evaluation of the biological safety of

  14. Cytocompatibility of direct water synthesized cadmium selenide quantum dots in colo-205 cells

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Torres, Marcos R. [Universidad Metropolitana, Nanomaterials Science Laboratory, School of Science and Technology (United States); Velez, Christian; Zayas, Beatriz [Universidad Metropolitana, ChemTox Laboratory, School of Environmental Affairs (United States); Rivera, Osvaldo [Universidad Metropolitana, Nanomaterials Science Laboratory, School of Science and Technology (United States); Arslan, Zikri [Jackson State University, Department of Chemistry (United States); Gonzalez-Vega, Maxine N. [Universidad Metropolitana, Nanomaterials Science Laboratory, School of Science and Technology (United States); Diaz-Diestra, Daysi; Beltran-Huarac, Juan; Morell, Gerardo [University of Puerto Rico, Molecular Science Research Center (United States); Primera-Pedrozo, Oliva M., E-mail: oprimera1@suagm.edu [Universidad Metropolitana, Nanomaterials Science Laboratory, School of Science and Technology (United States)

    2015-06-15

    Cadmium selenide quantum dots (CdSe QDs), inorganic semiconducting nanocrystals, are alluring increased attraction due to their highly refined chemistry, availability, and super tunable optical properties suitable for many applications in different research areas, such as photovoltaics, light-emitting devices, environmental sciences, and nanomedicine. Specifically, they are being widely used in bio-imaging in contrast to organic dyes due to their high brightness and improved photo-stability, and their ability to tune their absorption and emission spectra upon changing the crystal size. The production of CdSe QDs is mostly assisted by trioctylphosphine oxide compound, which acts as solvent or solubilizing agent and renders the QDs soluble in organic compounds (such as toluene, chloroform, and hexane) that are highly toxic. To circumvent the toxicity-related factor in CdSe QDs, we report the synthesis of CdSe QDs capped with thioglycolic acid (TGA) in an aqueous medium, and their biocompatibility in colo-205 cancer cells. In this study, the [Cd{sup 2+}]/[TGA] ratio was adjusted to 11:1 and the Se concentration (10 and 15 mM) was monitored in order to evaluate its influence on the optical properties and cytocompatibility. QDs resulted to be quite stable in water (after purification) and RPMI cell medium and no precipitation was observed for long contact times, making them appealing for in vitro experiments. The spectroscopy analysis, advanced electron microscopy, and X-ray diffractometry studies indicate that the final products were successfully formed exhibiting an improved optical response. Colo-205 cells being exposed to different concentrations of TGA-capped CdSe QDs for 12, 24, and 48 h with doses ranging from 0.5 to 2.0 mM show high tolerance reaching cell viabilities as high as 93 %. No evidence of cellular apoptotic pathways was observed as pointed out by our Annexin V assays at higher concentrations. Moreover, confocal microscopy analysis conducted to

  15. Genotoxicity of meso-2,3-dimercapto succinic acid-coated silver sulfide quantum dot

    OpenAIRE

    Deniz Özkan Vardar; ibrahim Hacıoğlu; Sevtap Aydin; Funda Yağcı

    2015-01-01

    Nanotecnology products have been used in wide applications in chemistry, electronics, energy generation, and medicine. Despite significant interest in developing quantum dots (QDs) for biomedical applications, many researchers are convinced that QDs will never be used for the treatment of patients because of their potential toxicity. In various in vitro cell culture studies, the cytotoxic properties of some QD have been demonstrated and they have been suggested to be toxic in humans. In this ...

  16. Time-dependent toxicity of cadmium telluride quantum dots on liver and kidneys in mice: histopathological changes with elevated free cadmium ions and hydroxyl radicals.

    Science.gov (United States)

    Wang, Mengmeng; Wang, Jilong; Sun, Hubo; Han, Sihai; Feng, Shuai; Shi, Lu; Meng, Peijun; Li, Jiayi; Huang, Peili; Sun, Zhiwei

    2016-01-01

    A complete understanding of the toxicological behavior of quantum dots (QDs) in vivo is of great importance and a prerequisite for their application in humans. In contrast with the numerous cytotoxicity studies investigating QDs, only a few in vivo studies of QDs have been reported, and the issue remains controversial. Our study aimed to understand QD-mediated toxicity across different time points and to explore the roles of free cadmium ions (Cd(2+)) and hydroxyl radicals (·OH) in tissue damage. Male ICR mice were administered a single intravenous dose (1.5 µmol/kg) of CdTe QDs, and liver and kidney function and morphology were subsequently examined at 1, 7, 14, and 28 days. Furthermore, ·OH production in the tissue was quantified by trapping · OH with salicylic acid (SA) as 2,3-dihydroxybenzoic acid (DHBA) and detecting it using a high-performance liquid chromatography fluorescence method. We used the induction of tissue metallothionein levels and 2,3-DHBA:SA ratios as markers for elevated Cd(2+) from the degradation of QDs and ·OH generation in the tissue, respectively. Our experimental results revealed that the QD-induced histopathological changes were time-dependent with elevated Cd(2+) and ·OH, and could recover after a period of time. The Cd(2+) and ·OH exhibited delayed effects in terms of histopathological abnormalities. Histological assessments performed at multiple time points might facilitate the evaluation of the biological safety of QDs.

  17. Continuous-Flow Synthesis and Materials Interface Engineering of Lead Sulfide Quantum Dots for Photovoltaic Applications

    KAUST Repository

    El-Ballouli, Ala’a O.

    2016-05-25

    Harnessing the Sun’s energy via the conversion of solar photons to electricity has emerged as a sustainable energy source to fulfill our future demands. In this regard, solution-processable, size-tunable PbS quantum dots (QDs) have been identified as a promising active materials for photovoltaics (PVs). Yet, there are still serious challenges that hinder the full exploitation of QD materials in PVs. This dissertation addresses two main challenges to aid these QDs in fulfilling their tremendous potential in PV applications. First, it is essential to establish a large-scale synthetic technique which maintains control over the reaction parameters to yield QDs with well-defined shape, size, and composition. Rigorous protocols for cost-effective production on a scale are still missing from literature. Particularly, previous reports of record-performance QD-PVs have been based on small-scale, manual, batch syntheses. One way to achieve a controlled large-scale synthesis is by reducing the reaction volume to ensure uniformity. Accordingly, we design a droplet-based continuous-flow synthesis of PbS QDs. Only upon separating the nucleation and growth phases, via a dual-temperature-stage reactor, it was possible to achieve high-quality QDs with high photoluminescence quantum yield (50%) in large-scale. The performance of these QDs in a PV device was comparable to batch-synthesized QDs, thus providing a promise in utilizing automated synthesis of QDs for PV applications. Second, it is crucial to study and control the charge transfer (CT) dynamics at QD interfaces in order to optimize their PV performance. Yet, the CT investigations based on PbS QDs are limited in literature. Here, we investigate the CT and charge separation (CS) at size-tunable PbS QDs and organic acceptor interfaces using a combination of femtosecond broadband transient spectroscopic techniques and steady-state measurements. The results reveal that the energy band alignment, tuned by the quantum

  18. SILAR deposition of nickel sulfide counter electrode for application in quantum dot sensitized solar cell

    Science.gov (United States)

    Singh, Navjot; Siwatch, Poonam; Arora, Anmol; Sharma, Jadab; Tripathi, S. K.

    2018-05-01

    Quantum Dot Sensitized Solar Cells are a likely replacement for Silicon-based solar cells. Counter electrodes are a fundamental aspect of QDSSC's performance. NiS being a less expensive material is a decent choice for the purpose. In this paper, we have discussed the synthesis of NiS by Successive Ionic Layer Adsorption Reaction. Optical, Crystallographic and Electrical studies have been presented. Electrical studies of the device with NiS counter electrode is compared with characteristics of the device with CNTs as the counter electrode. SILAR method is easy and less time to consume than chemical bath deposition or any other method. Results show the success of NiS synthesized by SILAR method as the counter electrode.

  19. Tunable ultrasmall visible-to-extended near-infrared emitting silver sulfide quantum dots for integrin-targeted cancer imaging.

    Science.gov (United States)

    Tang, Rui; Xue, Jianpeng; Xu, Baogang; Shen, Duanwen; Sudlow, Gail P; Achilefu, Samuel

    2015-01-27

    The large size of many near-infrared (NIR) fluorescent nanoparticles prevents rapid extravasation from blood vessels and subsequent diffusion to tumors. This confines in vivo uptake to the peritumoral space and results in high liver retention. In this study, we developed a viscosity modulated approach to synthesize ultrasmall silver sulfide quantum dots (QDs) with distinct tunable light emission from 500 to 1200 nm and a QD core diameter between 1.5 and 9 nm. Conjugation of a tumor-avid cyclic pentapeptide (Arg-Gly-Asp-DPhe-Lys) resulted in monodisperse, water-soluble QDs (hydrodynamic diameter < 10 nm) without loss of the peptide's high binding affinity to tumor-associated integrins (KI = 1.8 nM/peptide). Fluorescence and electron microscopy showed that selective integrin-mediated internalization was observed only in cancer cells treated with the peptide-labeled QDs, demonstrating that the unlabeled hydrophilic nanoparticles exhibit characteristics of negatively charged fluorescent dye molecules, which typically do not internalize in cells. The biodistribution profiles of intravenously administered QDs in different mouse models of cancer reveal an exceptionally high tumor-to-liver uptake ratio, suggesting that the small sized QDs evaded conventional opsonization and subsequent high uptake in the liver and spleen. The seamless tunability of the QDs over a wide spectral range with only a small increase in size, as well as the ease of labeling the bright and noncytotoxic QDs with biomolecules, provides a platform for multiplexing information, tracking the trafficking of single molecules in cells, and selectively targeting disease biomarkers in living organisms without premature QD opsonization in circulating blood.

  20. Ultrasmall visible-to-near-infrared emitting silver-sulfide quantum dots for cancer detection and imaging

    Science.gov (United States)

    Tang, Rui; Xu, Baogang; Shen, Duanwen; Sudlow, Gail; Achilefu, Samuel

    2018-02-01

    The large size of many near infrared (NIR) fluorescent nanoparticles prevents rapid extravasation from blood vessels and subsequent diffusion to tumors. This confines in vivo uptake to the peritumoral space and results in high liver retention. We developed a viscosity modulated approach to synthesize ultrasmall silver sulfide quantum dots (QDs) with distinct tunable light emission from visible to near-infrared in spectrum and a QD core diameter between less than 5 nm. Further functionalization of these Ag2S QDs with different type of molecules such as targeting peptides, retains monodisperse, relatively small water soluble QDs without loss of the functionality of the peptide's high binding affinity to cancerous tumor. Fluorescence and electron microscopy showed that selective integrin-mediated internalization was observed only in cancer cells treated with the peptide-labeled QDs, demonstrating that the unlabeled hydrophilic nanoparticles exhibit characteristics of negatively charged fluorescent dye molecules, which typically do not internalize in cells. The biodistribution profiles of intravenously administered QDs in different mouse models of cancer reveal an exceptionally high tumor-to-liver uptake ratio, suggesting that the small sized QDs evaded conventional opsonization and subsequent high uptake in the liver and spleen. The seamless tunability of the QDs over a wide spectral range with only a small increase in size, as well as the ease of labeling the bright and non-cytotoxic QDs with biomolecules, provides a platform for multiplexing information, tracking the trafficking of single molecules in cells, and selectively targeting disease biomarkers in living organisms without premature QD opsonization in circulating blood.

  1. Genotoxicity of meso-2,3-dimercapto succinic acid-coated silver sulfide quantum dot

    Directory of Open Access Journals (Sweden)

    Deniz Özkan Vardar

    2015-06-01

    Full Text Available Nanotecnology products have been used in wide applications in chemistry, electronics, energy generation, and medicine. Despite significant interest in developing quantum dots (QDs for biomedical applications, many researchers are convinced that QDs will never be used for the treatment of patients because of their potential toxicity. In various in vitro cell culture studies, the cytotoxic properties of some QD have been demonstrated and they have been suggested to be toxic in humans. In this study, the cytotoxic properties of Ag2S-(Meso-2,3-Dimercapto Succinic acid nanomaterials in V79 cells (Chinese lung fibroblast cell line were determined by MTT assay. The genotoxic effects of Ag2S-(Meso-2,3-Dimercapto Succinic acid were evaluated by the alkaline single cell gel electrophoresis. The cells were treated with Ag2S-(Meso-2,3-Dimercapto Succinic acid at the concentrations of 5- 2000 µg/ml. No cytotoxic effect of Ag2S-(Meso-2,3-Dimercapto Succinic acid at all concentrations studied was observed. No significant increases in DNA damage were found at the studied concentrations when compared to negative control in V79 cells. In conclusion, further in vitro and in vivo studies are required to determine the safety doses of Ag2S-(Meso-2,3-Dimercapto Succinic acid.

  2. Quantum-mechanical calculations of the electronic structure of calcium and cadmium vanadate apatites

    International Nuclear Information System (INIS)

    Karbovskij, V.L.; Soroka, A.P.; Kasiyanenko, V.Kh.; Shpak, A.P.

    2011-01-01

    Electronic structures of compounds Me 10 (VO 4 ) 6 X 2 , where Me = Ca or Cd and X = F, Cl, OH are investigated using the full potential APW + lo method. The degrees of distortions of VO 4- tetrahedra with respect to the Td point group are analyzed using a relaxation of atomic positions. Apatites in the form of Ca 10 (VO 4 ) 6 X 2 , where X = F, Cl, OH, are established to decrease the band gap by 0.5-1.0 eV under the isomorphic substitution of calcium for cadmium. Apatites Ca 10 (VO 4 ) 6 X 2 , where X = F, Cl, OH are proven to decrease the degree of covalency of the oxygen-halogen bond under the isomorphic substitution of calcium for cadmium.

  3. Selenium Sulfide

    Science.gov (United States)

    Selenium sulfide, an anti-infective agent, relieves itching and flaking of the scalp and removes the dry, ... Selenium sulfide comes in a lotion and is usually applied as a shampoo. As a shampoo, selenium ...

  4. Enhanced performance of hybrid solar cells using longer arms of quantum cadmium selenide tetrapods

    KAUST Repository

    Lee, Kyu-Sung

    2011-12-01

    We demonstrate that enhanced device performance of hybrid solar cells based on tetrapod (TP)-shaped cadmium selenide (CdSe) nanoparticles and conjugated polymer of poly (3-hexylthiophene) (P3HT) can be obtained by using longer armed tetrapods which aids in better spatial connectivity, thus decreasing charge hopping events which lead to better charge transport. Longer tetrapods with 10 nm arm length lead to improved power conversion efficiency of 1.12% compared to 0.80% of device having 5 nm short-armed tetrapods:P3HT photoactive blends.

  5. Enhanced performance of hybrid solar cells using longer arms of quantum cadmium selenide tetrapods

    KAUST Repository

    Lee, Kyu-Sung; Kim, Inho; Gullapalli, Sravani; Wong, Michael S.; Jabbour, Ghassan E.

    2011-01-01

    We demonstrate that enhanced device performance of hybrid solar cells based on tetrapod (TP)-shaped cadmium selenide (CdSe) nanoparticles and conjugated polymer of poly (3-hexylthiophene) (P3HT) can be obtained by using longer armed tetrapods which aids in better spatial connectivity, thus decreasing charge hopping events which lead to better charge transport. Longer tetrapods with 10 nm arm length lead to improved power conversion efficiency of 1.12% compared to 0.80% of device having 5 nm short-armed tetrapods:P3HT photoactive blends.

  6. Zinc Cadmium Selenide Cladded Quantum Dot Based Electroluminescent and Nonvolatile Memory Devices

    Science.gov (United States)

    Al-Amody, Fuad H.

    This dissertation presents electroluminescent (EL) and nonvolatile memory devices fabricated using pseudomorphic ZnCdSe-based cladded quantum dots (QDs). These dots were grown using our own in-school built novel reactor. The EL device was fabricated on a substrate of ITO (indium tin oxide) coated glass with the quantum dots sandwiched between anode and cathode contacts with a small barrier layer on top of the QDs. The importance of these cladded dots is to increase the quantum yield of device. This device is unique as they utilize quantum dots that are pseudomorphic (nearly lattice-matched core and the shell of the dot). In the case of floating quantum dot gate nonvolatile memory, cladded ZnCdSe quantum dots are deposited on single crystalline gate insulator (ZnMgS/ZnMgSe), which is grown using metal-organic chemical vapor deposition (MOCVD). The control gate dielectric layer of the nonvolatile memory is Si3N4 or SiO2 and is grown using plasma enhanced chemical vapor deposition (PECVD). The cladded dots are grown using an improved methodology of photo-assisted microwave plasma metal-organic chemical vapor deposition (PMP-MOCVD) enhanced reactor. The cladding composition of the core and shell of the dots was engineered by the help of ultraviolet light which changed the incorporation of zinc (and hence composition of ZnCdSe). This makes ZnxCd1--xSe-ZnyCd1--y Se QDs to have a low composition of zinc in the core than the cladding (x

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

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Song; Cai, Qingsong [The Institute of Environmental and Human Health, Texas Tech University, Lubbock, TX 79416 (United States); Chibli, Hicham [Department of Biomedical Engineering, McGill University, Montréal, QC H3A 2B4 (Canada); Allagadda, Vinay [The Institute of Environmental and Human Health, Texas Tech University, Lubbock, TX 79416 (United States); Nadeau, Jay L. [Department of Biomedical Engineering, McGill University, Montréal, QC H3A 2B4 (Canada); Mayer, Gregory D., E-mail: greg.mayer@ttu.edu [The Institute of Environmental and Human Health, Texas Tech University, Lubbock, TX 79416 (United States)

    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.

  8. Localized surface plasmon and exciton interaction in silver-coated cadmium sulphide quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, P.; Rustagi, K. C.; Vasa, P.; Singh, B. P., E-mail: bhanuprs@gmail.com [Department of Physics, Indian Institute of Technology Bombay, Mumbai- 400076 (India)

    2015-05-15

    Localized surface plasmon and exciton coupling has been investigated on colloidal solutions of silver-coated CdS nanoparticles (NPs), synthesized by gamma irradiation. Two broad photoluminescence (PL) bands (blue/red) corresponding to band to band and defect state transitions have been observed for the bare and coated samples. In case of bare CdS NPs, the intensity of the red PL peak is about ten times higher than the blue PL peak intensity. However, on coating the CdS NPs with silver, the peak intensity of the blue PL band gets enhanced and becomes equal to that of the red PL band. High-resolution transmission electron microscopic (HRTEM) images adequately demonstrate size distribution of these metal/semiconductor nanocomposites. UV-Vis absorption studies show quantum confinement effect in these semiconductor quantum dot (SQD) systems. Absorption spectrum of silver-coated SQDs shows signature of surface plasmon-exciton coupling which has been theoretically verified.

  9. Efficient solution-processed small molecule: Cadmium selenide quantum dot bulk heterojunction solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Vinay, E-mail: drvinaygupta@netscape.net [Physics of Energy Harvesting Division, Organic and Hybrid Solar Cell Group, CSIR-National Physical Laboratory, New Delhi-110012 (India); Department of Physics, University of California, Santa Barbara, California 93106 (United States); Upreti, Tanvi; Chand, Suresh [Physics of Energy Harvesting Division, Organic and Hybrid Solar Cell Group, CSIR-National Physical Laboratory, New Delhi-110012 (India)

    2013-12-16

    We report bulk heterojunction solar cells based on blends of solution-processed small molecule [7,7′-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b′]dithiophene-2,6-diyl) bis(6-fluoro-4-(5′-hexyl-[2,2′-bithiophen]-5yl)benzo[c] [1,2,5] thiadiazole)] p-DTS(FBTTh{sub 2}){sub 2}: Cadmium Selenide (CdSe) (70:30, 60:40, 50:50, and 40:60) in the device configuration: Indium Tin Oxide /poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/p-DTS(FBTTh{sub 2}){sub 2}: CdSe/Ca/Al. The optimized ratio of p-DTS(FBTTh{sub 2}){sub 2}:CdSe::60:40 leads to a short circuit current density (J{sub sc}) = 5.45 mA/cm{sup 2}, open circuit voltage (V{sub oc}) = 0.727 V, and fill factor (FF) = 51%, and a power conversion efficiency = 2.02% at 100 mW/cm{sup 2} under AM1.5G illumination. The J{sub sc} and FF are sensitive to the ratio of p-DTS(FBTTh{sub 2}){sub 2}:CdSe, which is a crucial factor for the device performance.

  10. Efficient solution-processed small molecule: Cadmium selenide quantum dot bulk heterojunction solar cells

    International Nuclear Information System (INIS)

    Gupta, Vinay; Upreti, Tanvi; Chand, Suresh

    2013-01-01

    We report bulk heterojunction solar cells based on blends of solution-processed small molecule [7,7′-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b′]dithiophene-2,6-diyl) bis(6-fluoro-4-(5′-hexyl-[2,2′-bithiophen]-5yl)benzo[c] [1,2,5] thiadiazole)] p-DTS(FBTTh 2 ) 2 : Cadmium Selenide (CdSe) (70:30, 60:40, 50:50, and 40:60) in the device configuration: Indium Tin Oxide /poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/p-DTS(FBTTh 2 ) 2 : CdSe/Ca/Al. The optimized ratio of p-DTS(FBTTh 2 ) 2 :CdSe::60:40 leads to a short circuit current density (J sc ) = 5.45 mA/cm 2 , open circuit voltage (V oc ) = 0.727 V, and fill factor (FF) = 51%, and a power conversion efficiency = 2.02% at 100 mW/cm 2 under AM1.5G illumination. The J sc and FF are sensitive to the ratio of p-DTS(FBTTh 2 ) 2 :CdSe, which is a crucial factor for the device performance

  11. Determination of Hydrogen Sulfide in Fermentation Broths Containing SO21

    Science.gov (United States)

    Acree, T. E.; Sonoff, Elisabeth P.; Splittstoesser, D. F.

    1971-01-01

    A procedure for the determination of hydrogen sulfide in fermentation broths containing up to 100 μg of SO2 per ml is described. The method involves the sparging of H2S from the broth into a cadmium hydroxide absorption solution, the formation of methylene blue from the absorbed sulfide, and the measuring of this color spectrophotometrically. The use of cadmium hydroxide instead of zinc acetate, the common absorbent, substantially reduced the interference of SO2 with the analysis. PMID:5111300

  12. PEG-phospholipid-encapsulated bismuth sulfide and CdSe/ZnS quantum dot core–shell nanoparticle and its computed tomography/fluorescence performance

    International Nuclear Information System (INIS)

    Chen, Jun; Yang, Xiao-Quan; Qin, Meng-Yao; Zhang, Xiao-Shuai; Xuan, Yang; Zhao, Yuan-Di

    2015-01-01

    In this paper, polyethylene glycol-phospholipid structure is used to synthesize hybrid cluster of 40–50 nm diameter that contains hydrophobic bismuth sulfide nanoparticles and CdSe/ZnS quantum dots. The composite probe’s toxicity, CT imaging, and fluorescence imaging performance are also studied. Experimental results show that the nanocomposite hybrid cluster has obvious CT contrast enhancement and fluorescence imaging capability in vitro even after cellular uptake. It gives a CT number of 700 (Hounsfield units) at 15 mg/mL, higher than that of the current iobitridol CT contrast agent. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide experiment reveals that it has low cytotoxicity at concentration up to of 3.14 mg/mL of Bi, indicating the composite probe has potential ability for CT and fluorescence bimodal imaging

  13. Comment on 'Unconventional gap state of trapped exciton in lead sulfide quantum dots'

    Energy Technology Data Exchange (ETDEWEB)

    Curry, R J, E-mail: r.j.curry@surrey.ac.uk [Advanced Technology Institute, University of Surrey, Guildford, Surrey, GU2 7XH (United Kingdom)

    2011-06-10

    In a recent paper (Lewis et al 2010 Nanotechnology 21 45502) proposed a previously unidentified gap state within lead sulfide nanocrystals (PbS-NCs) based on analysis of their temperature dependent optical properties. In the following we argue that due to oversights in the analysis of the data presented, inconsistencies arise which question their exclusion of 'dark' excitonic states as the origin of the observed effects. (comment)

  14. Purification processes of cadmium based quantum dots in aqueous medium: a comparative study

    Science.gov (United States)

    Petris, Dimitri; Freitas, Denilson V.; dos Santos, Rayany K. V.; Dias, Jéssica M. M.; Navarro, Marcelo

    2017-07-01

    Three different purification methods for CdTe-MPA quantum dot (QD) were performed in aqueous medium: acid titration (HCl, HClO4, H2SO4 and CH3COOH), non-selective precipitation by addition of acetone and co-precipitation of the QD in the presence of inorganic salts. The QD stock solutions were prepared by an electrochemical method of synthesis, in four different heating times (1 h, 4 h, 8 h and 12 h). After purifications, the QD solids were redispersed in distilled water and analyzed by absorption and emission spectra. The λ abs and λ em of the purified QDs showed similar data observed for QD stock solutions, and the recovery rate varied from 71% to 99%. Co-precipitation method showed some advantages: quantum yield maintenance of the QD redispersed solution, longer period of storage (over 6 months) in solution and in solid state (QD embedded into the KCl crystal lattice). CdSe-MPA and CdS-MPA solutions were also purified by co-precipitation method with KCl, showing good results as observed for CdTe-MPA.

  15. Comparative studies of biological activity of cadmium-based quantum dots with different surface modifications

    Science.gov (United States)

    Kalinowska, D.; Grabowska-Jadach, I.; Drozd, M.; Pietrzak, M.

    2018-05-01

    This paper presents a modification of the surface of CdS/ZnS and CdSe x S1-x /ZnS quantum dots (QDs) with 3-mercaptopropionic and 6-mercaptohexanoic acid. The obtained QDs were characterized using TEM, DLS, UV-Vis, and fluorescence spectroscopy. Flow cytometry was applied to evaluate the cytotoxicity of QDs and examine the type of death caused by the tested nanoparticles. In addition, the generation of reactive oxygen species after incubation of the tested cells with CdSe x S1-x /ZnS-MPA and CdSe x S1-x /ZnS-MHA QDs was evaluated. The study was conducted on three cell lines: adherent (A549 and MRC-5) and suspension ones (K562). The conducted research demonstrated that the tested nanoparticles exhibit concentration-dependent toxicity. It was observed that the surface modification influences the toxicity level of the examined QDs, and modification of their surface with the use of the ligand of longer carbon chain (MHA) reduces the toxicity in comparison with QDs-MPA. It was also found that all tested QDs caused the death of cells in the course of necrosis. Based on obtained results, it was concluded that the cytotoxicity of QDs is to a large extent related to reactive oxygen species (ROS) generation.

  16. Studies of the absorbance peak on the N719 dye influence by combination between Cadmium Selenide (CdSeQDs and Zinc Sulfide(ZnSQDs

    Directory of Open Access Journals (Sweden)

    Saad Mohammad Azren

    2018-01-01

    Full Text Available The absorption rate of the photoanode can be influenced by the combination between the difference semiconductor quantum dot sensitizer. Six samples were prepared with difference weight percent (wt% of ZnS from 0% to 50% and constant wt% of CdSe which then will be called as semiconductor QDs were immersed in 0.5mM of N719 dye. The purity of ZnS powder and CdSe powder was determined using x-ray diffraction (XRD.The ultraviolet-visible spectrophotometry (Uv-Vis use to investigate the absorption spectrum and absorbance peak of this sample. 50 wt% of ZnS is the best composition to increase the absorbance peak of the photoanode. The Cyclic voltammetry (CV of varying wt% of ZnS, found that the 40 wt% of ZnS is suitable combination for a DSSC’s photoanode and produced the higher current.

  17. Highly sensitive FRET-based fluorescence immunoassay for aflatoxin B1 using cadmium telluride quantum dots

    International Nuclear Information System (INIS)

    Zekavati, Roya; Bayat, Mansour; Safi, Shahabeddin; Hashemi, Seyed Jamal; Rahmani-Cherati, Tavoos; Tabatabaei, Meisam; Mohsenifar, Afshin

    2013-01-01

    We report on a competitive immunoassay for the determination of aflatoxin B1 using fluorescence resonance energy transfer (FRET) from anti-aflatoxin B1 antibody (immobilized on the shell of CdTe quantum dots) to Rhodamine 123 (Rho 123-labeled aflatoxin B1 bound to albumin). The highly specific immuno reaction between the antibody against aflatoxin B1 on the QDs and the labeled-aflatoxin B1 brings the Rho 123 fluorophore (acting as the acceptor) and the QDs (acting as the donor) in close spatial proximity and causes FRET to occur upon photoexcitation of the QDs. In the absence of unlabeled aflatoxin B1, the antigen-antibody complex is stable, and strong emission resulting from the FRET from QDs to labeled aflatoxin B1 is observed. In the presence of aflatoxin B1, it will compete with the labeled aflatoxin B1-albumin complex for binding to the antibody-QDs conjugate so that FRET will be increasingly suppressed. The reduction in the fluorescence intensity of the acceptor correlates well with the concentration of aflatoxin B1. The feasibility of the method was established by the detection of aflatoxin B1 in spiked human serum. There is a linear relationship between the increased fluorescence intensity of Rho 123 with increasing concentration of aflatoxin B1 in spike human serum, over the range of 0.1–0.6 μmol·mL −1 . The limit of detection is 2 × 10 −11 M. This homogeneous competitive detection scheme is simple, rapid and efficient, and does not require excessive washing and separation steps. (author)

  18. Tissue specific responses to cadmium-based quantum dots in the marine mussel Mytilus galloprovincialis

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Thiago Lopes [CIMA, Faculty of Science and Technology, University of Algarve, Campus de Gambelas, 8005-139 Faro (Portugal); Gomes, Tânia [CIMA, Faculty of Science and Technology, University of Algarve, Campus de Gambelas, 8005-139 Faro (Portugal); Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, NO-0349 Oslo (Norway); Mestre, Nélia C.; Cardoso, Cátia [CIMA, Faculty of Science and Technology, University of Algarve, Campus de Gambelas, 8005-139 Faro (Portugal); Bebianno, Maria João, E-mail: mbebian@ualg.pt [CIMA, Faculty of Science and Technology, University of Algarve, Campus de Gambelas, 8005-139 Faro (Portugal)

    2015-12-15

    Highlights: • Mussel gills are the main target for oxidative stress induced by Cd-based QDs. • Antioxidants responses induced by Cd-based QDs and dissolved Cd are mediated by different mechanisms. • CdTe QDs are more pro-oxidant Cd form when compared to dissolved Cd. • Differential tissue response indicated nano-specific effects. - Abstract: In recent years, Cd-based quantum dots (QDs) have generated interest from the life sciences community due to their potential applications in nanomedicine, biology and electronics. However, these engineered nanomaterials can be released into the marine environment, where their environmental health hazards remain unclear. This study investigated the tissue-specific responses related to alterations in the antioxidant defense system induced by CdTe QDs, in comparison with its dissolved counterpart, using the marine mussel Mytilus galloprovincialis. Mussels were exposed to CdTe QDs and dissolved Cd for 14 days at 10 μgCd L{sup −1} and biomarkers of oxidative stress [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidases (total, Se-independent and Se-dependent GPx) and glutathione-S-transferase (GST) activities] were analyzed along with Cd accumulation in the gills and digestive gland of mussels. Results show that both Cd forms changed mussels’ antioxidant responses with distinct modes of action (MoA). There were tissue- and time-dependent differences in the biochemical responses to each Cd form, wherein QDs are more pro-oxidant when compared to dissolved Cd. The gills are the main tissue affected by QDs, with effects related to the increase of SOD, GST and GPx activities, while those of dissolved Cd was associated to the increase of CAT activity, Cd accumulation and exposure time. Digestive gland is a main tissue for accumulation of both Cd forms, but changes in antioxidant enzyme activities are smaller than in gills. A multivariate analysis revealed that the antioxidant patterns are tissue dependent

  19. Synthesis of Bi_2S_3 quantum dots for sensitized solar cells by reverse SILAR

    International Nuclear Information System (INIS)

    Singh, Navjot; Sharma, J.; Tripathi, S. K.

    2016-01-01

    Quantum Dot Sensitized Solar cells (QDSSC) have great potential to replace silicon-based solar cells. Quantum dots of various materials and sizes could be used to convert most of the visible light into the electrical current. This paper put emphasis on the synthesis of Bismuth Sulphide quantum dots and selectivity of the anionic precursor by Successive Ionic Layer Adsorption Reaction (SILAR). Bismuth Sulfide (Bi_2S_3) (group V – Vi semiconductor) is strong contestant for cadmium free solar cells due to its optimum band gap for light harvesting. Optical, structural and electrical measurements are reported and discussed. Problem regarding the choice of precursor for anion extraction is discussed. Band gap of the synthesized quantum dots is 1.2 eV which does not match with the required energy band gap of bismuth sulfide that is 1.7 eV.

  20. Synthesis of Bi2S3 quantum dots for sensitized solar cells by reverse SILAR

    Science.gov (United States)

    Singh, Navjot; Sharma, J.; Tripathi, S. K.

    2016-05-01

    Quantum Dot Sensitized Solar cells (QDSSC) have great potential to replace silicon-based solar cells. Quantum dots of various materials and sizes could be used to convert most of the visible light into the electrical current. This paper put emphasis on the synthesis of Bismuth Sulphide quantum dots and selectivity of the anionic precursor by Successive Ionic Layer Adsorption Reaction (SILAR). Bismuth Sulfide (Bi2S3) (group V - Vi semiconductor) is strong contestant for cadmium free solar cells due to its optimum band gap for light harvesting. Optical, structural and electrical measurements are reported and discussed. Problem regarding the choice of precursor for anion extraction is discussed. Band gap of the synthesized quantum dots is 1.2 eV which does not match with the required energy band gap of bismuth sulfide that is 1.7eV.

  1. Critical review of animal carcinogenesis by cadmium and its inorganic compounds

    International Nuclear Information System (INIS)

    Maximilien, R.; Dero, B.

    1990-01-01

    Animal carcinogenic biassays relative to 6 inorganic cadmium substances (cadmium metal, cadmium oxide, cadmium sulfide, cadmium sulfate, cadmium chloride and cadmium acetate) are reviewed (speciation). Critical evaluation of literature data on carcinogenicity has been performed by making reference to E.C. guidelines of good laboratory practice. There are few data on routes relevant for human risk assessment: experiments on inhalation demonstrate lung carcinogenicity of cadmium oxide, cadmium sulfide, cadmium sulfate and cadmium chloride in rats but not in mice nor in hamsters; no carcinogenic effects of cadmium compounds are observed following oral administration. For routes of less or no relevance for human risk assessment, some results are clearly positive: subcutaneous injection induces cancers in situ (various cadmium compounds), testicular tumours (cadmium sulfate and cadmium chloride) and prostatic tumours (cadmium chloride) but such effects are not observed using relevant malignancies in rats. With respect to other no relevant routes (intraperitoneal, intrarenal...) tumours are incidentally produced in situ, but not in remote organs. Numerous studies fail to demonstrate cadmium carcinogenicity, but methodologically acceptable negative ones are very limited in number. Accordingly strain dependent effects and dose effect relationship could not be thoroughly assessed

  2. Synthesis of Bi{sub 2}S{sub 3} quantum dots for sensitized solar cells by reverse SILAR

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Navjot; Sharma, J. [University Institute of Emerging Areas in Science and Technology Centre for Nano Science and Technology, Panjab University, Chandigarh-160025 (India); Tripathi, S. K., E-mail: surya@pu.ac.in, E-mail: surya-tr@yahoo.com [University Institute of Emerging Areas in Science and Technology Centre for Nano Science and Technology, Panjab University, Chandigarh-160025 (India); Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh-160 014 (India)

    2016-05-06

    Quantum Dot Sensitized Solar cells (QDSSC) have great potential to replace silicon-based solar cells. Quantum dots of various materials and sizes could be used to convert most of the visible light into the electrical current. This paper put emphasis on the synthesis of Bismuth Sulphide quantum dots and selectivity of the anionic precursor by Successive Ionic Layer Adsorption Reaction (SILAR). Bismuth Sulfide (Bi{sub 2}S{sub 3}) (group V – Vi semiconductor) is strong contestant for cadmium free solar cells due to its optimum band gap for light harvesting. Optical, structural and electrical measurements are reported and discussed. Problem regarding the choice of precursor for anion extraction is discussed. Band gap of the synthesized quantum dots is 1.2 eV which does not match with the required energy band gap of bismuth sulfide that is 1.7 eV.

  3. Fluorescence turn-on sensing of trace cadmium ions based on EDTA-etched CdTe@CdS quantum dot.

    Science.gov (United States)

    Wang, Si-Nan; Zhu, Jian; Li, Xin; Li, Jian-Jun; Zhao, Jun-Wu

    2018-05-01

    Cadmium-caused environmental pollution and diseases have always been worldwide problems. Thus it is extremely urgent to establish a cheap, rapid, simple and selective detection method for trace cadmium in drinking water. In this study, a fluorescence "turn-on" method based on ethylene diamine tetraacetic acid (EDTA)-etched CdTe@CdS quantum dots (QDs) was designed to detect Cd 2+ . High resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) were utilized for chemical and structural characterization of the as-prepared QDs. Based on chemical etching of EDTA on the surface of CdTe@CdS QDs, specific Cd 2+ recognition sites were produced, and then results in fluorescence quenching. The introduction of Cd 2+ could identify these sites and restore the fluorescence of the EDTA-QDs system. Under the optimum conditions, the nanoprobe shows a linear response range from 0.05 to 9 μM with a very low detection limit of 0.032 μM. In addition, the reported fluorescence probe in this work displays a good selectivity for trace Cd 2+ over other metal ions and an admirable practicability in real water samples. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. One-step synthesis of DNA functionalized cadmium-free quantum dots and its application in FRET-based protein sensing

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Cuiling, E-mail: clzhang@chem.ecnu.edu.cn [Department of Chemistry, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200241 (China); Ding, Caiping [Department of Chemistry, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200241 (China); Zhou, Guohua [School of Chemistry and Chemical Engineering, Lingnan Normal University, Zhanjiang, 524048 (China); Xue, Qin [Department of Chemistry, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200241 (China); Xian, Yuezhong, E-mail: yzxian@chem.ecnu.edu.cn [Department of Chemistry, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200241 (China)

    2017-03-08

    DNA functionalized quantum dots (QDs) are promising nanoprobes for the fluorescence resonance energy transfer (FRET)-based biosensing. Herein, cadmium-free DNA functionalized Mn-doped ZnS (DNA-ZnS:Mn{sup 2+}) QDs were successfully synthesized by one-step route. As-synthesized QDs show excellent photo-stability with the help of PAA and DNA. Then, we constructed a novel FRET model based on the QDs and WS{sub 2} nanosheets as the energy donor-acceptor pairs, which was successfully applied for the protein detection through the terminal protection of small molecule-linked DNA assay. This work not only explores the potential bioapplication of the DNA-ZnS:Mn{sup 2+} QDs, but also provides a platform for the investigation of small molecule-protein interaction. - Highlights: • The stable and cadmium-free DNA functionalized ZnS:Mn{sup 2+} QDs were successfully synthesized through a facile one-step route. • We constructed a novel FRET system based on one-step synthesized DNA-ZnS:Mn{sup 2+} QDs (donor) and WS{sub 2} nanosheets (acceptor). • The FRET-based strategy was applied for the detection of streptavidin and folate receptor by combining TPSMLD and Exo III.

  5. Cadmium carcinogenesis

    International Nuclear Information System (INIS)

    Waalkes, Michael P.

    2003-01-01

    Cadmium is a heavy metal of considerable environmental and occupational concern. Cadmium compounds are classified as human carcinogens by several regulatory agencies. The most convincing data that cadmium is carcinogenic in humans comes from studies indicating occupational cadmium exposure is associated with lung cancer. Cadmium exposure has also been linked to human prostate and renal cancer, although this linkage is weaker than for lung cancer. Other target sites of cadmium carcinogenesis in humans, such as liver, pancreas and stomach, are considered equivocal. In animals, cadmium effectively induces cancers at multiple sites and by various routes. Cadmium inhalation in rats induces pulmonary adenocarcinomas, in accord with its role in human lung cancer. Cadmium can induce tumors and/or preneoplastic lesions within the rat prostate after ingestion or injection. At relatively high doses, cadmium induces benign testicular tumors in rats, but these appear to be due to early toxic lesions and loss of testicular function, rather than from a specific carcinogenic effect of cadmium. Like many other metals, cadmium salts will induce mesenchymal tumors at the site of subcutaneous (s.c.) or intramuscular (i.m.) injections, but the human relevance of these is dubious. Other targets of cadmium in rodents include the liver, adrenal, pancreas, pituitary, and hematopoietic system. With the exception of testicular tumors in rodents, the mechanisms of cadmium carcinogenesis are poorly defined. Cadmium can cause any number of molecular lesions that would be relevant to oncogenesis in various cellular model systems. Most studies indicate cadmium is poorly mutagenic and probably acts through indirect or epigenetic mechanisms, potentially including aberrant activation of oncogenes and suppression of apoptosis

  6. Cadmium carcinogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Waalkes, Michael P

    2003-12-10

    Cadmium is a heavy metal of considerable environmental and occupational concern. Cadmium compounds are classified as human carcinogens by several regulatory agencies. The most convincing data that cadmium is carcinogenic in humans comes from studies indicating occupational cadmium exposure is associated with lung cancer. Cadmium exposure has also been linked to human prostate and renal cancer, although this linkage is weaker than for lung cancer. Other target sites of cadmium carcinogenesis in humans, such as liver, pancreas and stomach, are considered equivocal. In animals, cadmium effectively induces cancers at multiple sites and by various routes. Cadmium inhalation in rats induces pulmonary adenocarcinomas, in accord with its role in human lung cancer. Cadmium can induce tumors and/or preneoplastic lesions within the rat prostate after ingestion or injection. At relatively high doses, cadmium induces benign testicular tumors in rats, but these appear to be due to early toxic lesions and loss of testicular function, rather than from a specific carcinogenic effect of cadmium. Like many other metals, cadmium salts will induce mesenchymal tumors at the site of subcutaneous (s.c.) or intramuscular (i.m.) injections, but the human relevance of these is dubious. Other targets of cadmium in rodents include the liver, adrenal, pancreas, pituitary, and hematopoietic system. With the exception of testicular tumors in rodents, the mechanisms of cadmium carcinogenesis are poorly defined. Cadmium can cause any number of molecular lesions that would be relevant to oncogenesis in various cellular model systems. Most studies indicate cadmium is poorly mutagenic and probably acts through indirect or epigenetic mechanisms, potentially including aberrant activation of oncogenes and suppression of apoptosis.

  7. Doped zinc sulfide quantum dots based phosphorescence turn-off/on probe for detecting histidine in biological fluid

    Energy Technology Data Exchange (ETDEWEB)

    Bian, Wei [School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006 (China); School of Basic Medical Science, Shanxi Medical University, Taiyuan 030001 (China); Wang, Fang [School of Basic Medical Science, Shanxi Medical University, Taiyuan 030001 (China); Wei, Yanli; Wang, Li; Liu, Qiaoling; Dong, Wenjuan [School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006 (China); Shuang, Shaomin, E-mail: smshuang@sxu.edu.cn [School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006 (China); Choi, Martin M.F., E-mail: mmfchoi@gmail.com [Partner State Key Laboratory of Environmental and Biological Analysis, and Department of Chemistry, Hong Kong Baptist University, 224 Waterloo Road, Kowloon Tong, Hong Kong SAR (China)

    2015-01-26

    Highlights: • A turn-on phosphorescence quantum dots probe for histidine is fabricated. • High sensitivity, good selectivity and low interference are achieved. • Histidine in urine samples can be easily detected by the phosphorescence probe. - Abstract: We report a turn-on phosphorescence probe for detection of histidine based on Co{sup 2+}-adsorbed N-acetyl-L-cysteine (NAC) capped Mn: ZnS quantum dots (QDs) which is directly synthesized by the hydrothermal method. The phosphorescence of NAC-Mn: ZnS QDs is effectively quenched by Co{sup 2+} attributing to the adsorption of Co{sup 2+} onto the surface of QDs with a concomitant in suppressing the recombination process of hole and electron of QDs. The phosphorescence of Co{sup 2+}-adsorbed NAC-Mn: ZnS QDs can be recovered by binding of Co{sup 2+} with histidine. The quenching and regeneration of the phosphorescence of NAC-Mn: ZnS QDs have been studied in detail. The as-prepared QDs-based probe is applied to determine histidine with a linear range of 1.25–30 μM and a detection limit of 0.74 μM. The relative standard deviation for eleven repeat detections of 20 μM histidine is 0.65%. Co{sup 2+}-adsorbed NAC-Mn: ZnS QDs show high sensitivity and good selectivity to histidine over other amino acids, metal ions and co-existing substances. The proposed QDs probe has been successfully applied to determination of histidine in human urine samples with good recoveries of 98.5–103%.

  8. Cathodoluminescence and ion implantation of cadmium sulphide/cuprous sulphide solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Glew, R W; Bryant, F J

    1975-10-01

    By the use of implantation with copper ions or oxygen ions of 50 keV energy, changes in the cathodoluminescence emission spectrum from cadmium sulfide/cuprous sulfide thin film manufactured solar cells have been correlated with changes in the phases of the cuprous sulfide layer. Thus, monitoring the relative intensities of cathodoluminescence emission bands affords a method of assessing the cuprous sulfide layer and possibly predicting the performance of the cells.

  9. On the size and temperature dependence of the energy gap in cadmium-selenide quantum dots embedded in fluorophosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Lipatova, Zh. O., E-mail: zluka-yo@mail.ru; Kolobkova, E. V.; Babkina, A. N.; Nikonorov, N. V. [ITMO University (Russian Federation)

    2017-03-15

    The temperature and size dependences of the energy gap in CdSe quantum dots with diameters of 2.4, 4.0, and 5.2 nm embedded in fluorophosphate glasses are investigated. It is shown that the temperature coefficient of the band gap dE{sub g}/dT in the quantum dots differs from the bulk value and depends strictly on the dot size. It is found that, furthermore, the energy of each transition in these quantum dots is characterized by an individual temperature coefficient dE/dT.

  10. Phosphate Favors the Biosynthesis of CdS Quantum Dots in Acidithiobacillus thiooxidans ATCC 19703 by Improving Metal Uptake and Tolerance

    Directory of Open Access Journals (Sweden)

    Giovanni Ulloa

    2018-02-01

    Full Text Available Recently, we reported the production of Cadmium sulfide (CdS fluorescent semiconductor nanoparticles (quantum dots, QDs by acidophilic bacteria of the Acidithiobacillus genus. Here, we report that the addition of inorganic phosphate to Acidithiobacillus thiooxidans ATCC 19703 cultures favors the biosynthesis of CdS QDs at acidic conditions (pH 3.5. The effect of pH, phosphate and cadmium concentrations on QDs biosynthesis was studied by using Response Surface Methodology (RSM, a multivariate technique for analytical optimization scarcely used in microbiological studies to date. To address how phosphate affects intracellular biosynthesis of CdS QDs, the effect of inorganic phosphate on bacterial cadmium-uptake was evaluated. By measuring intracellular levels of cadmium we determined that phosphate influences the capacity of cells to incorporate this metal. A relation between cadmium tolerance and phosphate concentrations was also determined, suggesting that phosphate participates in the adaptation of bacteria to toxic levels of this metal. In addition, QDs-biosynthesis was also favored by the degradation of intracellular polyphosphates. Altogether, our results indicate that phosphate contributes to A. thiooxidans CdS QDs biosynthesis by influencing cadmium uptake and cadmium tolerance. These QDs may also be acting as a nucleation point for QDs formation at acidic pH. This is the first study reporting the effect of phosphates on QDs biosynthesis and describes a new cadmium-response pathway present in A. thiooxidans and most probably in other bacterial species.

  11. Phosphate Favors the Biosynthesis of CdS Quantum Dots in Acidithiobacillus thiooxidans ATCC 19703 by Improving Metal Uptake and Tolerance

    Science.gov (United States)

    Ulloa, Giovanni; Quezada, Carolina P.; Araneda, Mabel; Escobar, Blanca; Fuentes, Edwar; Álvarez, Sergio A.; Castro, Matías; Bruna, Nicolás; Espinoza-González, Rodrigo; Bravo, Denisse; Pérez-Donoso, José M.

    2018-01-01

    Recently, we reported the production of Cadmium sulfide (CdS) fluorescent semiconductor nanoparticles (quantum dots, QDs) by acidophilic bacteria of the Acidithiobacillus genus. Here, we report that the addition of inorganic phosphate to Acidithiobacillus thiooxidans ATCC 19703 cultures favors the biosynthesis of CdS QDs at acidic conditions (pH 3.5). The effect of pH, phosphate and cadmium concentrations on QDs biosynthesis was studied by using Response Surface Methodology (RSM), a multivariate technique for analytical optimization scarcely used in microbiological studies to date. To address how phosphate affects intracellular biosynthesis of CdS QDs, the effect of inorganic phosphate on bacterial cadmium-uptake was evaluated. By measuring intracellular levels of cadmium we determined that phosphate influences the capacity of cells to incorporate this metal. A relation between cadmium tolerance and phosphate concentrations was also determined, suggesting that phosphate participates in the adaptation of bacteria to toxic levels of this metal. In addition, QDs-biosynthesis was also favored by the degradation of intracellular polyphosphates. Altogether, our results indicate that phosphate contributes to A. thiooxidans CdS QDs biosynthesis by influencing cadmium uptake and cadmium tolerance. These QDs may also be acting as a nucleation point for QDs formation at acidic pH. This is the first study reporting the effect of phosphates on QDs biosynthesis and describes a new cadmium-response pathway present in A. thiooxidans and most probably in other bacterial species. PMID:29515535

  12. Cadmium-free aqueous synthesis of ZnSe and ZnSe@ZnS core-shell quantum dots and their differential bioanalyte sensing potential

    Science.gov (United States)

    Mir, Irshad Ahmad; Rawat, Kamla; Bohidar, H. B.

    2016-10-01

    Herein we report a facile and cadmium-free approach to prepare water-soluble fluorescent ZnSe@ZnS core-shell quantum dots (QDs), using thioglycolic acid (TGA) ligand as a stabilizer and thiourea as a sulfur source. The optical properties and morphology of the obtained core-shell QDs were characterized by UV-vis and fluorescence spectroscopy, transmission electron microscopy (TEM), energy-dispersive x-ray analysis (EDX), x-ray diffraction (XRD), electrophoresis and dynamic light scattering (DLS) techniques. TEM analysis, and electrophoresis data showed that ZnSe core had an average size of 3.60 ± 0.12 nm and zeta potential of -38 mV; and for ZnSe@ZnS QDs, the mean size was 4.80 ± 0.20 nm and zeta potential was -45 mV. Compared to the core ZnSe QDs, the quantum yield of these core-shell structures was higher (13% versus 32%). These were interacted with five common bioanalytes such as, ascorbic acid, citric acid, oxalic acid, glucose and cholesterol which revealed fluorescence quenching due to concentration dependent binding of analytes to the core only, and core-shell QDs. The binding pattern followed the sequence: cholesterol ascorbic acid acid acid for ZnSe, and cholesterol acid ascorbic acid acid for core-shell QDs. Thus, enhanced binding was noticed for the analyte citric acid which may facilitate development of a fluorescence-based sensor based on the ZnSe core-only quantum dot platform. Further, the hydrophilic core-shell structure may find use in cell imaging applications.

  13. Functionalization of Cadmium Selenide Quantum Dots with Poly(ethylene glycol): Ligand Exchange, Surface Coverage, and Dispersion Stability.

    Science.gov (United States)

    Wenger, Whitney Nowak; Bates, Frank S; Aydil, Eray S

    2017-08-22

    Semiconductor quantum dots synthesized using rapid mixing of precursors by injection into a hot solution of solvents and surfactants have surface ligands that sterically stabilize the dispersions in nonpolar solvents. Often, these ligands are exchanged to disperse the quantum dots in polar solvents, but quantitative studies of quantum dot surfaces before and after ligand exchange are scarce. We studied exchanging trioctylphosphine (TOP) and trioctylphosphine oxide (TOPO) ligands on as-synthesized CdSe quantum dots dispersed in hexane with a 2000 g/mol thiolated poly(ethylene glycol) (PEG) polymer. Using infrared spectroscopy we quantify the absolute surface concentration of TOP/TOPO and PEG ligands per unit area before and after ligand exchange. While 50-85% of the TOP/TOPO ligands are removed upon ligand exchange, only a few are replaced with PEG. Surprisingly, the remaining TOP/TOPO ligands outnumber the PEG ligands, but these few PEG ligands are sufficient to disperse the quantum dots in polar solvents such as chloroform, tetrahydrofuran, and water. Moreover, as-synthesized quantum dots once easily dispersed in hexane are no longer dispersible in nonpolar solvents after ligand exchange. A subtle coverage-dependent balance between attractive PEG-solvent interactions and repulsive TOP/TOPO-solvent interactions determines the dispersion stability.

  14. Influence of the temperature on the synthesis of CdS quantum dots stabilized with poly (vinil alcohol)

    International Nuclear Information System (INIS)

    Carvalho, Andre L.B. de; Mansur, Alexandra A.P.; Mansur, Herman S.; Gonzalez, Juan C.

    2011-01-01

    Semiconductor nanoparticles (Quantum Dots, QDs) have been the subject of recent research by presenting quantum properties. This property has stimulated the study of these particles in biological applications such as bookmarks, which creates the necessity of using different synthesis routes resulting in biocompatible systems. Thus, this study aimed to evaluate the effect of temperature on the properties of QDs cadmium sulfide, aqueous route using poly (vinyl alcohol), a biocompatible polymer, such as stabilizing agent. The characterization of particles produced was performed by UV-Vis spectroscopy and photoluminescence (PL) spectra for obtaining the absorption and emission, respectively and Transmission microscopy (TEM) for analysis of the diameter of the nanocrystals. (author)

  15. The Determination of Hydrogen Sulfide in Stack Gases, Iodometric Titration After Sulfite Removal.

    Science.gov (United States)

    Robles, E. G.

    The determination of hydrogen sulfide in effluents from coal-fired furnaces and incinerators is complicated by the presence of sulfur oxides (which form acids). Organic compounds also may interfere with or prevent the formation of the cadmium sulfide precipitate or give false positive results because of reaction with iodine. The report presents a…

  16. Effects of Long-term exposure of Gelatinated and Non-gelatinated Cadmium Telluride Quantum Dots on Differentiated PC12 cells

    LENUS (Irish Health Repository)

    Prasad, Babu R

    2012-01-20

    Abstract Background The inherent toxicity of unmodified Quantum Dots (QDs) is a major hindrance to their use in biological applications. To make them more potent as neuroprosthetic and neurotherapeutic agents, thioglycolic acid (TGA) capped CdTe QDs, were coated with a gelatine layer and investigated in this study with differentiated pheochromocytoma 12 (PC12) cells. The QD - cell interactions were investigated after incubation periods of up to 17 days by MTT and APOTOX-Glo Triplex assays along with using confocal microscopy. Results Long term exposure (up to 17 days) to gelatinated TGA-capped CdTe QDs of PC12 cells in the course of differentiation and after neurites were grown resulted in dramatically reduced cytotoxicity compared to non-gelatinated TGA-capped CdTe QDs. Conclusion The toxicity mechanism of QDs was identified as caspase-mediated apoptosis as a result of cadmium leaking from the core of QDs. It was therefore concluded that the gelatine capping on the surface of QDs acts as a barrier towards the leaking of toxic ions from the core QDs in the long term (up to 17 days).

  17. Nanostructured silver sulfide: synthesis of various forms and their application

    Science.gov (United States)

    Sadovnikov, S. I.; Rempel, A. A.; Gusev, A. I.

    2018-04-01

    The results of experimental studies on nanostructured silver sulfide are analyzed and generalized. The influence of small particle size on nonstoichiometry of silver sulfide is discussed. Methods for the synthesis of various forms of nanostructured Ag2S including nanopowders, stable colloidal solutions, quantum dots, core–shell nanoparticles and heteronanostructures are described. The advantages and drawbacks of different synthetic procedures are analyzed. Main fields of application of nanostructured silver sulfide are considered. The bibliography includes 184 references.

  18. Eco-friendly intracellular biosynthesis of CdS quantum dots without changing Escherichia coli's antibiotic resistance.

    Science.gov (United States)

    Yan, Zheng-Yu; Du, Qing-Qing; Qian, Jing; Wan, Dong-Yu; Wu, Sheng-Mei

    2017-01-01

    In the paper, a green and efficient biosynthetical technique was reported for preparing cadmium sulfide (CdS) quantum dots, in which Escherichia coli (E. coli) was chosen as a biomatrix. Fluorescence emission spectra and fluorescent microscopic photographs revealed that as-produced CdS quantum dots had an optimum fluorescence emission peak located at 470nm and emitted a blue-green fluorescence under ultraviolet excitation. After extracted from bacterial cells and located the nanocrystals' foci in vivo, the CdS quantum dots showed a uniform size distribution by transmission electron microscope. Through the systematical investigation of the biosynthetic conditions, including culture medium replacement, input time point of cadmium source, working concentrations of raw inorganic ions, and co-cultured time spans of bacteria and metal ions in the bio-manufacture, the results revealed that CdS quantum dots with the strongest fluorescence emission were successfully prepared when E. coli cells were in stationary phase, with the replacement of culture medium and following the incubation with 1.0×10 -3 mol/L cadmium source for 2 days. Results of antimicrobial susceptibility testing indicated that the sensitivities to eight types of antibiotics of E. coli were barely changed before and after CdS quantum dots were prepared in the mild temperature environment, though a slight fall of antibiotic resistance could be observed, suggesting hinted the proposed technique of producing quantum dots is a promising environmentally low-risk protocol. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Cadmium Alternatives

    Science.gov (United States)

    2012-08-01

    carcinogenic, leachable Trivalent and non- chrome passivates generally struggle with conductivity Major Differences in Trivalent vs. Hexavalent Passivates...for Change Cadmium passivated with hexavalent chromium has been in use for many decades Cadmium is toxic, and is classified as a priority...Executive Orders 13514 & 13423 DoD initiatives – Young memo (April 2009) DFAR restricting use of hexavalent chromium Allows the use of hexavalent

  20. Charge transport through exciton shelves in cadmium chalcogenide quantum dot-DNA nano-bioelectronic thin films

    Science.gov (United States)

    Goodman, Samuel M.; Noh, Hyunwoo; Singh, Vivek; Cha, Jennifer N.; Nagpal, Prashant

    2015-02-01

    Quantum dot (QD), or semiconductor nanocrystal, thin films are being explored for making solution-processable devices due to their size- and shape-tunable bandgap and discrete higher energy electronic states. While DNA has been extensively used for the self-assembly of nanocrystals, it has not been investigated for the simultaneous conduction of multiple energy charges or excitons via exciton shelves (ES) formed in QD-DNA nano-bioelectronic thin films. Here, we present studies on charge conduction through exciton shelves, which are formed via chemically coupled QDs and DNA, between electronic states of the QDs and the HOMO-LUMO levels in the complementary DNA nucleobases. While several challenges need to be addressed in optimizing the formation of devices using QD-DNA thin films, a higher charge collection efficiency for hot-carriers and our detailed investigations of charge transport mechanism in these thin films highlight their potential for applications in nano-bioelectronic devices and biological transducers.

  1. Charge transport through exciton shelves in cadmium chalcogenide quantum dot-DNA nano-bioelectronic thin films

    Energy Technology Data Exchange (ETDEWEB)

    Goodman, Samuel M.; Singh, Vivek [Department of Chemical and Biological Engineering, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, Colorado 80303 (United States); Noh, Hyunwoo [Department of Chemical and Biological Engineering, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, Colorado 80303 (United States); Materials Science and Engineering Program and Department of Nanoengineering, University of California, 9500 Gilman Drive, La Jolla, San Diego, California 92093 (United States); Cha, Jennifer N. [Department of Chemical and Biological Engineering, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, Colorado 80303 (United States); Materials Science and Engineering Program and Department of Nanoengineering, University of California, 9500 Gilman Drive, La Jolla, San Diego, California 92093 (United States); Materials Science and Engineering, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, Colorado 80303 (United States); Nagpal, Prashant, E-mail: pnagpal@colorado.edu [Department of Chemical and Biological Engineering, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, Colorado 80303 (United States); Materials Science and Engineering, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, Colorado 80303 (United States); BioFrontiers Institute, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, Colorado 80303 (United States); Renewable and Sustainable Energy Institute, University of Colorado Boulder, 2445 Kittredge Loop, Boulder, Colorado 80309 (United States)

    2015-02-23

    Quantum dot (QD), or semiconductor nanocrystal, thin films are being explored for making solution-processable devices due to their size- and shape-tunable bandgap and discrete higher energy electronic states. While DNA has been extensively used for the self-assembly of nanocrystals, it has not been investigated for the simultaneous conduction of multiple energy charges or excitons via exciton shelves (ES) formed in QD-DNA nano-bioelectronic thin films. Here, we present studies on charge conduction through exciton shelves, which are formed via chemically coupled QDs and DNA, between electronic states of the QDs and the HOMO-LUMO levels in the complementary DNA nucleobases. While several challenges need to be addressed in optimizing the formation of devices using QD-DNA thin films, a higher charge collection efficiency for hot-carriers and our detailed investigations of charge transport mechanism in these thin films highlight their potential for applications in nano-bioelectronic devices and biological transducers.

  2. Charge transport through exciton shelves in cadmium chalcogenide quantum dot-DNA nano-bioelectronic thin films

    International Nuclear Information System (INIS)

    Goodman, Samuel M.; Singh, Vivek; Noh, Hyunwoo; Cha, Jennifer N.; Nagpal, Prashant

    2015-01-01

    Quantum dot (QD), or semiconductor nanocrystal, thin films are being explored for making solution-processable devices due to their size- and shape-tunable bandgap and discrete higher energy electronic states. While DNA has been extensively used for the self-assembly of nanocrystals, it has not been investigated for the simultaneous conduction of multiple energy charges or excitons via exciton shelves (ES) formed in QD-DNA nano-bioelectronic thin films. Here, we present studies on charge conduction through exciton shelves, which are formed via chemically coupled QDs and DNA, between electronic states of the QDs and the HOMO-LUMO levels in the complementary DNA nucleobases. While several challenges need to be addressed in optimizing the formation of devices using QD-DNA thin films, a higher charge collection efficiency for hot-carriers and our detailed investigations of charge transport mechanism in these thin films highlight their potential for applications in nano-bioelectronic devices and biological transducers

  3. SULFIDE MINERALS IN SEDIMENTS

    Science.gov (United States)

    The formation processes of metal sulfides in sediments, especially iron sulfides, have been the subjects of intense scientific research because of linkages to the global biogeochemical cycles of iron, sulfur, carbon, and oxygen. Transition metal sulfides (e.g., NiS, CuS, ZnS, Cd...

  4. Sulfide Mineral Surfaces

    International Nuclear Information System (INIS)

    Rosso, Kevin M.; Vaughan, David J.

    2006-01-01

    The past twenty years or so have seen dramatic development of the experimental and theoretical tools available to study the surfaces of solids at the molecular (?atomic resolution?) scale. On the experimental side, two areas of development well illustrate these advances. The first concerns the high intensity photon sources associated with synchrotron radiation; these have both greatly improved the surface sensitivity and spatial resolution of already established surface spectroscopic and diffraction methods, and enabled the development of new methods for studying surfaces. The second centers on the scanning probe microscopy (SPM) techniques initially developed in the 1980's with the first scanning tunneling microscope (STM) and atomic force microscope (AFM) experiments. The direct 'observation' of individual atoms at surfaces made possible with these methods has truly revolutionized surface science. On the theoretical side, the availability of high performance computers coupled with advances in computational modeling has provided powerful new tools to complement the advances in experiment. Particularly important have been the quantum mechanics based computational approaches such as density functional theory (DFT), which can now be easily used to calculate the equilibrium crystal structures of solids and surfaces from first principles, and to provide insights into their electronic structure. In this chapter, we review current knowledge of sulfide mineral surfaces, beginning with an overview of the principles relevant to the study of the surfaces of all crystalline solids. This includes the thermodynamics of surfaces, the atomic structure of surfaces (surface crystallography and structural stability, adjustments of atoms at the surface through relaxation or reconstruction, surface defects) and the electronic structure of surfaces. We then discuss examples where specific crystal surfaces have been studied, with the main sulfide minerals organized by structure type

  5. Sulfide Mineral Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Rosso, Kevin M.; Vaughan, David J.

    2006-08-01

    The past twenty years or so have seen dramatic development of the experimental and theoretical tools available to study the surfaces of solids at the molecular (?atomic resolution?) scale. On the experimental side, two areas of development well illustrate these advances. The first concerns the high intensity photon sources associated with synchrotron radiation; these have both greatly improved the surface sensitivity and spatial resolution of already established surface spectroscopic and diffraction methods, and enabled the development of new methods for studying surfaces. The second centers on the scanning probe microscopy (SPM) techniques initially developed in the 1980's with the first scanning tunneling microscope (STM) and atomic force microscope (AFM) experiments. The direct 'observation' of individual atoms at surfaces made possible with these methods has truly revolutionized surface science. On the theoretical side, the availability of high performance computers coupled with advances in computational modeling has provided powerful new tools to complement the advances in experiment. Particularly important have been the quantum mechanics based computational approaches such as density functional theory (DFT), which can now be easily used to calculate the equilibrium crystal structures of solids and surfaces from first principles, and to provide insights into their electronic structure. In this chapter, we review current knowledge of sulfide mineral surfaces, beginning with an overview of the principles relevant to the study of the surfaces of all crystalline solids. This includes the thermodynamics of surfaces, the atomic structure of surfaces (surface crystallography and structural stability, adjustments of atoms at the surface through relaxation or reconstruction, surface defects) and the electronic structure of surfaces. We then discuss examples where specific crystal surfaces have been studied, with the main sulfide minerals organized by

  6. Influence of the temperature on the synthesis of CdS quantum dots stabilized with poly (vinil alcohol); Influencia da temperatura na sintese de pontos quanticos de sulfeto de cadmio estabilizados por poli (alcool vinilico)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    Semiconductor nanoparticles (Quantum Dots, QDs) have been the subject of recent research by presenting quantum properties. This property has stimulated the study of these particles in biological applications such as bookmarks, which creates the necessity of using different synthesis routes resulting in biocompatible systems. Thus, this study aimed to evaluate the effect of temperature on the properties of QDs cadmium sulfide, aqueous route using poly (vinyl alcohol), a biocompatible polymer, such as stabilizing agent. The characterization of particles produced was performed by UV-Vis spectroscopy and photoluminescence (PL) spectra for obtaining the absorption and emission, respectively and Transmission microscopy (TEM) for analysis of the diameter of the nanocrystals. (author)

  7. Chemical bath deposited zinc sulfide buffer layers for copper indium gallium sulfur-selenide solar cells and device analysis

    International Nuclear Information System (INIS)

    Kundu, Sambhu; Olsen, Larry C.

    2005-01-01

    Cadmium-free copper indium gallium sulfur-selenide (CIGSS) thin film solar cells have been fabricated using chemical bath deposited (CBD) zinc sulfide (ZnS) buffer layers. Shell Solar Industries provided high quality CIGSS absorber layers. The use of CBD-ZnS, which is a higher band gap material than CdS, improved the quantum efficiency of fabricated cells at lower wavelengths, leading to an increase in short circuit current. The best cell to date yielded an active area (0.43 cm 2 ) efficiency of 13.3%. The effect of the ZnS buffer layer thickness on device performance was studied carefully. This paper also presents a discussion of issues relevant to the use of the CBD-ZnS buffer material for improving device performance

  8. Recombination barrier layers in solid-state quantum dot-sensitized solar cells

    KAUST Repository

    Roelofs, Katherine E.

    2012-06-01

    By replacing the dye in the dye-sensitized solar cell design with semiconductor quantum dots as the light-absorbing material, solid-state quantum dot-sensitized solar cells (ss-QDSSCs) were fabricated. Cadmium sulfide quantum dots (QDs) were grown in situ by successive ion layer adsorption and reaction (SILAR). Aluminum oxide recombination barrier layers were deposited by atomic layer deposition (ALD) at the TiO2/hole-conductor interface. For low numbers of ALD cycles, the Al2O3 barrier layer increased open circuit voltage, causing an increase in device efficiency. For thicker Al2O3 barrier layers, photocurrent decreased substantially, leading to a decrease in device efficiency. © 2012 IEEE.

  9. Purification of hydrogen sulfide

    International Nuclear Information System (INIS)

    Tsao, U.

    1978-01-01

    A process is described for purifying a hydrogen sulfide gas stream containing carbon dioxide, comprising (a) passing the gas stream through a bed of solid hydrated lime to form calcium hydrosulfide and calcium carbonate and (b) regenerating hydrogen sulfide from said calcium hydrosulfide by reacting the calcium hydrosulfide with additional carbon dioxide. The process is especially applicable for use in a heavy water recovery process wherein deuterium is concentrated from a feed water containing carbon dioxide by absorption and stripping using hydrogen sulfide as a circulating medium, and the hydrogen sulfide absorbs a small quantity of carbon dioxide along with deuterium in each circulation

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

    International Nuclear Information System (INIS)

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

    2010-01-01

    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 A ring for Cd-S that was similar to cadmium sulfide with an inter-atomic distance of 2.52 A ring 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. Optical sensing of 3-phenoxybenzoic acid as a pyrethroid pesticides exposure marker by surface imprinting polymer capped on manganese-doped zinc sulfide quantum dots

    Directory of Open Access Journals (Sweden)

    Vivek Pandey

    2015-09-01

    Full Text Available The present communication deals with the synthesis of luminescent Mn-doped ZnS quantum dots (QDs anchored to surface imprinted polymer for the optical sensing of 3-phenoxy benzoic acid (3-PBA in urine samples. The combination of sensing and surface functionalization not only improves the selectivity of the method, but also increases the optosensing ability of the material for non-phosphorescent substances. The developed material was utilized for the selective and sensitive detection of 3-PBA in urine samples. The proposed method shows good linearity with a regression coefficient (R2 of 0.98. The limit of detection was found to be 0.117 μM. The method has an acceptable precision and accuracy which are found to be less than 8% and 80–90% respectively at three different concentrations. The quenching constant of quantum dot-molecular imprinted polymer was found to be 3.4 times higher to that of the quantum dot-non imprinted polymer (QD-NIP as calculated by Stern–Volmer equation. The sensing method developed has shown immense utility to detect 3-PBA in complex biological samples like urine.

  12. Quantum

    CERN Document Server

    Al-Khalili, Jim

    2003-01-01

    In this lively look at quantum science, a physicist takes you on an entertaining and enlightening journey through the basics of subatomic physics. Along the way, he examines the paradox of quantum mechanics--beautifully mathematical in theory but confoundingly unpredictable in the real world. Marvel at the Dual Slit experiment as a tiny atom passes through two separate openings at the same time. Ponder the peculiar communication of quantum particles, which can remain in touch no matter how far apart. Join the genius jewel thief as he carries out a quantum measurement on a diamond without ever touching the object in question. Baffle yourself with the bizzareness of quantum tunneling, the equivalent of traveling partway up a hill, only to disappear then reappear traveling down the opposite side. With its clean, colorful layout and conversational tone, this text will hook you into the conundrum that is quantum mechanics.

  13. Cadmium and the kidney.

    OpenAIRE

    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; cha...

  14. Effect of gamma-ray irradiation on the size and properties of CdS quantum dots in reverse micelles

    International Nuclear Information System (INIS)

    Bekasova, O.D.; Revina, A.A.; Rusanov, A.L.; Kornienko, E.S.; Kurganov, B.I.

    2013-01-01

    Cadmium sulfide quantum dots 1.3–5.6 nm in size have been synthesized in sodium bis(2-ethylhexy1)sulfosuccinate (AOT)–water–isooctane micellar solutions with various [H 2 O]/[AOT] molar ratios (w=2.5, 5.0 or 10). Gamma irradiation method has been used to change the size and optical properties of quantum dots. It has been found that γ-irradiation reduces the size polydispersity of quantum dots in the micellar system and alters their fluorescent properties. Fluorescence intensity is enhanced after γ-irradiation. The average fluorescence lifetime of single quantum dots sized 5.2±0.4 nm increases from 5.14 to 6.39 ns after γ-irradiation at a dose of 7.9 kGy. To the best of our knowledge, this is the first report on fluorescence lifetime of single CdS quantum dots in micellar solution. - Highlights: • Gamma irradiation method has been used successfully to change the size and optical properties of CdS quantum dots synthesized in micellar solutions. • γ-Irradiation reduces the size polydispersity of quantum dots in the micellar system. • Fluorescence intensity of CdS quantum dots is enhanced after γ-irradiation. • Fluorescence lifetime of single CdS quantum dots increases after γ-irradiation

  15. Highly Fluorescent Ribonuclease-A-Encapsulated Lead Sulfide Quantum Dots for Ultrasensitive Fluorescence in Vivo Imaging in the Second Near-Infrared Window

    OpenAIRE

    Kong, Yifei; Chen, Jun; Fang, Hongwei; Heath, George; Wo, Yan; Wang, Weili; Li, Yunxia; Guo, Yuan; Evans, Stephen D.; Chen, Shiyi; Zhou, Dejian

    2016-01-01

    Ribonuclease-A (RNase-A) encapsulated PbS quantum dots (RNase-A@PbS Qdots) which emit in the second near-infrared biological window (NIR-II, ca. 1000?1400 nm) are rapidly synthesized under microwave heating. Photoluminescence (PL) spectra of the Qdots can be tuned across the entire NIR-II range by simply controlling synthesis temperature. The size and morphology of the Qdots are examined by transmission electron microscopy (TEM), atomic force microscopy (AFM), and dynamic light scattering (DL...

  16. Mesostructured metal germanium sulfides

    Energy Technology Data Exchange (ETDEWEB)

    MacLachlan, M.J.; Coombs, N.; Bedard, R.L.; White, S.; Thompson, L.K.; Ozin, G.A.

    1999-12-29

    A new class of mesostructured metal germanium sulfide materials has been prepared and characterized. The synthesis, via supramolecular assembly of well-defined germanium sulfide anionic cluster precursors and transition-metal cations in formamide, represents a new strategy for the formation of this class of solids. A variety of techniques were employed to examine the structure and composition of the materials. Structurally, the material is best described as a periodic mesostructured metal sulfide-based coordination framework akin to periodic hexagonal mesoporous silica, MCM-41. At the molecular scale, the materials strongly resemble microstructured metal germanium sulfides, in which the structure of the [Ge{sub 4}S{sub 10}]{sup 4{minus}} cluster building-blocks are intact and linked via {mu}-S-M-S bonds. Evidence for a metal-metal bond in mesostructured Cu/Ge{sub 4}S{sub 10} is also provided.

  17. High-pressure phase diagram of hydrogen and deuterium sulfides from first principles: Structural and vibrational properties including quantum and anharmonic effects

    Science.gov (United States)

    Bianco, Raffaello; Errea, Ion; Calandra, Matteo; Mauri, Francesco

    2018-06-01

    We study the structural and vibrational properties of the high-temperature superconducting sulfur trihydride and trideuteride in the high-pressure I m 3 ¯m and R 3 m phases by first-principles density-functional-theory calculations. On lowering pressure, the rhombohedral transition I m 3 ¯m →R 3 m is expected, with hydrogen-bond desymmetrization and occurrence of trigonal lattice distortion. With both Perdew-Burke-Ernzerhof (PBE) and Becke-Lee-Yang-Parr (BLYP) exchange-correlation functional, in hydrostatic conditions we find that, contrary to what is suggested in some recent experiments, if the rhombohedral distortion exists it affects mainly the hydrogen bonds, whereas the resulting cell distortion is minimal. We estimate that the occurrence of a stress anisotropy of approximately 10 % could explain this discrepancy. Assuming hydrostatic conditions, we calculate the critical pressure at which the rhombohedral transition occurs. Quantum and anharmonic effects, which are relevant in this system, are included at nonperturbative level with the stochastic self-consistent harmonic approximation. Within this approach, we determine the transition pressure by calculating the free-energy Hessian, a method that allows to estimate the critical pressure with much higher precision (and much lower computational cost) compared with the free-energy "finite-difference" approach previously used. Using PBE and BLYP, we find that quantum anharmonic effects are responsible for a strong reduction of the critical pressure with respect to the one obtained with the classical harmonic approach. Interestingly, for the two functionals, even if the transition pressures at classical harmonic level differ by 83 GPa, the transition pressures including quantum anharmonic effects differ only by 23 GPa. Moreover, we observe a prominent isotope effect, as we estimate higher transition pressure for D3S than for H3S . Finally, within the stochastic self-consistent harmonic approximation, with PBE

  18. Effects of the capping ligands, linkers and oxide surface on the electron injection mechanism of copper sulfide quantum dot-sensitized solar cells.

    Science.gov (United States)

    Suárez, Javier Amaya; Plata, Jose J; Márquez, Antonio M; Sanz, Javier Fdez

    2017-06-07

    Quantum dot-sensitized solar cells, QDSCs, are a clean and effective alternative to fossil fuels to reduce CO 2 emissions. However, the different components that constitute the QDSCs and the difficulty of isolating experimentally their effects on the performance of the whole system slow down the development of more efficient devices. In this work, DFT calculations are combined with a bottom-up approach to differentiate the effect of each component on the electronic structure and absorption spectra. First, Cu 2 S QDs were built including a U parameter to effectively describe the localization of electrons. The effect of capping agents is addressed using ligands with different electron-donating/withdrawing groups. The role of linkers and their adsorption on the oxide surface are also examined. Finally, we propose a main indirect electron injection mechanism based on the position of the peaks of the spectra.

  19. Cadmium, an environmental poison

    Energy Technology Data Exchange (ETDEWEB)

    Oestergaard, A K

    1974-04-15

    In recent years, industrial employment of cadmium has increased considerably. Cadmium is now present in the environment and has caused acute and chronic poisoning. Inhalation of cadmium vapor or dust causes pulmonary damage while the kidney is the critical organ in absorption of cadmium. The element accumulates in the kidney and causes tubular damage or 200 ppm in the renal cortex. In animal experiments, cadmium may cause raised blood pressure, sterility and malignant tumors. On account of the pronounced tendency of cadmium to accumulate and its toxicity, it is important to trace sources and to reduce exposure of the population. 62 references.

  20. Highly selective manganese-doped zinc sulfide quantum dots based label free phosphorescent sensor for phosphopeptides in presence of zirconium (IV).

    Science.gov (United States)

    Gong, Yan; Fan, Zhefeng

    2015-04-15

    We report a room-temperature phosphorescence (RTP) sensor for phosphopeptides based on zirconium (IV)-modulated mercaptopropionic acid (MPA)-capped Mn-doped ZnS quantum dots (QDs). This sensor incorporates the advantages of the well-known Zr(4+)-phosphopeptide affinity pair and the RTP properties of doped QDs. The RTP of Mn-doped ZnS QDs capped with MPA can be effectively quenched by Zr(4+). The high affinity of phosphopeptides to Zr(4+) enables the dissociation of the ion from the surface of MPA-capped ZnS QDs, thereby forming a stable complex with phosphopeptides in the solution, and recovering the RTP of the QDs. The Zr(4+)-induced RTP quenching and subsequent phosphopeptide-induced RTP recovery for MPA-capped ZnS QDs provide a solid basis for the present RTP sensor based on QDs for the detection of phosphopeptides. The detection limit for phosphopeptides is 0.9ngmL(-1), the relative standard deviations is 2.5%, and the recovery of urine and serum samples with phosphopeptides addition rangs from 96% to 105% at optimal conditions. The proposed method was successfully applied to biological fluids and obtained satisfactory results. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Cadmium purification with a vibrating reactor

    International Nuclear Information System (INIS)

    Torres, N.; Esna-Ashari, M.; Biallas, H.; Kangas, K.

    1986-01-01

    While electrolytically producing zinc from sulfide concentrates, purification is the most significant step. Impurities such as Co, Sn, Ge, Ni and Sb can cause extensive redissolution of the electrodeposited zinc, thus diminishing current efficiency. Other metals, particularly cadmium, lead and copper, can negatively affect zinc properties by deposition on the cathode. It is standard practice to use atomized zinc dust as a reducing agent in the purification process, either alone or combined with additives. In conventional operations, special facilities are necessary to produce zinc dust in an amount close to 8wt% of cathode production. This paper examines a technique which makes use of zinc granules instead of dust

  2. Process for removing and detoxifying cadmium from scrap metal including mixed waste

    International Nuclear Information System (INIS)

    Kronberg, J.W.

    1994-01-01

    Cadmium-bearing scrap from nuclear applications, such as neutron shielding and reactor control and safety rods, must usually be handled as mixed waste since it is radioactive and the cadmium in it is both leachable and highly toxic. Removing the cadmium from this scrap, and converting it to a nonleachable and minimally radioactive form, would greatly simplify disposal or recycling. A process now under development will do this by shredding the scrap; leaching it with reagents which selectively dissolve out the cadmium; reprecipitating the cadmium as its highly insoluble sulfide; then fusing the sulfide into a glassy matrix to bring its leachability below EPA limits before disposal. Alternatively, the cadmium may be recovered for reuse. A particular advantage of the process is that all reagents (except the glass frit) can easily be recovered and reused in a nearly closed cycle, minimizing the risk of radioactive release. The process does not harm common metals such as aluminum, iron and stainless steel, and is also applicable to non-nuclear cadmium-bearing scrap such as nickel-cadmium batteries

  3. Synthesis of optimized indium phosphide/zinc sulfide core/shell nanocrystals and titanium dioxide nanotubes for quantum dot sensitized solar cells

    Science.gov (United States)

    Lee, Seungyong

    Synthesis of InP/ZnS core/shell nanocrystals and TiO 2 nanotubes and the optimization study to couple them together were explored for quantum dot sensitized solar cells. Its intrinsic nontoxicity makes the direct band gap InP/ZnS core/shell be one of the most promising semiconductor nanocrystals for optoelectric applications, with the advantage of tuning the optical absorption range in the desired solar spectrum region. Highly luminescent and monodisperse InP/ZnS nanocrystals were synthesized in a non-coordinating solvent. By varying the synthesis scheme, different size InP/ZnS nanocrystals with emission peaks ranging from 520 nm to 620 nm were grown. For the purpose of ensuring air stability, a ZnS shell was grown. The ZnS shell improves the chemical stability in terms of oxidation prevention. Transmission electron microscopy (TEM) image shows that the nanocrystals are highly crystalline and monodisperse. Free-standing TiO2 nanotubes were produced by an anodization method using ammonium fluoride. The free-standing nanotubes were formed under the condition that the chemical dissolution speed associated with fluoride concentration was faster than the speed of Ti oxidation. Highly ordered free-standing anatase form TiO2 nanotubes, which are transformed by annealing at the optimized temperature, are expected to be ideal for coupling with the prepared InP/ZnS nanocrystals. Electrophoretic deposition was carried out to couple the InP/ZnS nanocrystals with the TiO2 nanotubes. Under the adjusted applied voltage condition, the current during the electrophoretic deposition decreased continuously with time. The amount of the deposited nanocrystals was estimated by calculation and the evenly deposited nanocrystals on the TiO2 nanotubes were observed by TEM.

  4. Synthesis of zinc sulfide by chemical vapor deposition using an organometallic precursor: Di-tertiary-butyl-disulfide

    International Nuclear Information System (INIS)

    Vasekar, Parag; Dhakal, Tara; Ganta, Lakshmikanth; Vanhart, Daniel; Desu, Seshu

    2012-01-01

    Zinc sulfide has gained popularity in the last few years as a cadmium-free heterojunction partner for thin film solar cells and is seen as a good replacement for cadmium sulfide due to better blue photon response and non-toxicity. In this work, zinc sulfide films are prepared using an organic sulfur source. We report a simple and repeatable process for development of zinc sulfide using a cost-effective and less hazardous organic sulfur source. The development of zinc sulfide has been studied on zinc oxide-coated glass where the zinc oxide is converted into zinc sulfide. Zinc oxide grown by atomic layer deposition as well as commercially available zinc oxide-coated glass was used. The zinc sulfide synthesis has been studied and the films are characterized using scanning electron microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and a UV–VIS spectrophotometer. XRD, XPS and optical characterization confirm the zinc sulfide phase formation. - Highlights: ► Synthesis of ZnS using a less-hazardous precursor, di-tertiary-butyl-disulfide. ► ZnS process optimized for two types of ZnO films. ► Preliminary results for a solar cell show an efficiency of 1.09%.

  5. Calcium enhances cadmium tolerance and decreases cadmium ...

    African Journals Online (AJOL)

    We aimed at characterizing mechanisms controlling cadmium accumulation in lettuce, which is a food crop showing one of the highest capacities to accumulate this toxic compound. In this study, plants from three lettuce varieties were grown for eight days on media supplemented or not with cadmium (15 μM CdCl2) and ...

  6. Sulfide oxidation in a biofilter

    DEFF Research Database (Denmark)

    Pedersen, Claus Lunde; Dezhao, Liu; Hansen, Michael Jørgen

    Observed hydrogen sulfide uptake rates in a biofilter treating waste air from a pig farm were too high to be explained within conventional limits of sulfide solubility, diffusion in a biofilm and bacterial metabolism. Clone libraries of 16S and 18S rRNA genes from the biofilter found no sulfide...... higher hydrogen sulfide uptake followed by oxidation catalyzed by iron-containing enzymes such as cytochrome c oxidase in a process uncoupled from energy conservation....

  7. Sulfide oxidation in a biofilter

    DEFF Research Database (Denmark)

    Pedersen, Claus Lunde; Liu, Dezhao; Hansen, Michael Jørgen

    2012-01-01

    Observed hydrogen sulfide uptake rates in a biofilter treating waste air from a pig farm were too high to be explained within conventional limits of sulfide solubility, diffusion in a biofilm and bacterial metabolism. Clone libraries of 16S and 18S rRNA genes from the biofilter found no sulfide...... higher hydrogen sulfide uptake followed by oxidation catalyzed by iron-containing enzymes such as cytochrome c oxidase in a process uncoupled from energy conservation....

  8. Titanocene sulfide chemistry

    Czech Academy of Sciences Publication Activity Database

    Horáček, Michal

    2016-01-01

    Roč. 314, MAY 2016 (2016), s. 83-102 ISSN 0010-8545 R&D Projects: GA ČR(CZ) GAP207/12/2368 Institutional support: RVO:61388955 Keywords : titanocene sulfide chemistry * photolysis * titanocene hydrosulfides Ti-(SH)n Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 13.324, year: 2016

  9. Electron transfer to sulfides:

    International Nuclear Information System (INIS)

    Meneses, Ana Belen; Antonello, Sabrina; Arevalo, Maria Carmen; Maran, Flavio

    2005-01-01

    The problem of characterizing the steps associated with the dissociative reduction of sulfides has been addressed. The electrochemical reduction of diphenylmethyl para-methoxyphenyl sulfide in N,N-dimethylformamide, on both glassy carbon and mercury electrodes, was chosen as a test system. The electrode process involves the slow heterogeneous outer-sphere electron transfer to the sulfide, the fast cleavage of the C-S bond, the reduction of the ensuing carbon radical, and the self-protonation triggered by the generation of the strong base Ph 2 CH - . The latter reaction is rather slow, in agreement with the large intrinsic barriers characterizing proton transfers between CH-acids and carbon bases. The dissociative reduction was studied in the presence of an exogenous acid. The results, obtained by convolution analysis, point to a stepwise DET mechanism in which the ET step is accompanied by rather large reorganization energy. Similar results were obtained on both electrode materials. Analysis of the heterogeneous electron transfer and associated C-S bond cleavage indicate that the reduction of this and other sulfides lies between the stepwise dissociative electron transfers leading to the formation of stiff π* radical anions and those going through the intermediacy of loose σ* radical anions

  10. Deep penetration of polonium implanted in cadmium sulfide

    International Nuclear Information System (INIS)

    Weinmann, E.

    1975-01-01

    The distribution of 25 keV 210 Po implanted into CdS platelets was determined by means of energy analysis of the α-particles emitted by the 210 Po. Two samples were implanted along an axial channeling direction, and one along a planar channeling direction. The resulting distributions did not conform to any of the existing range theories or, in the case of axial channeling, to existing diffusion theories. A new diffusion model was formulated and fitted to the experimental data. Good agreement was obtained between this model and experiment for both the axial and the planar channeling conditions. The stopping power of CdS for He ions was measured as a preliminary step to the Po distribution measurement. A new technique was used which consisted in measuring the energy spectrum of either He ions backscattered from Bi implanted in CdS or of α-particles emitted by 210 Po implanted in CdS. A thin layer was then etched off the surface of the sample and the energy spectrum was measured again. The stopping power was calculated from these two spectra and the known thickness of the removed layer. These measurements and calculations were made for energies ranging from 0.963 to 5.3 MeV with accuracies between 12 percent and 16 percent

  11. Peculiarities of luminescence of low-temperature-deformed cadmium sulfides

    Energy Technology Data Exchange (ETDEWEB)

    Negrij, V.D.; Osip' yan, Yu.A. (AN SSSR, Chernogolovka. Inst. Fiziki Tverdogo Tela)

    1982-02-01

    Spatially resolved photoluminescence of CdS crystals deformed at low temperatures is investigated. It is revealed that production and movement of certain dislocations, i. e. microplastic deformation take place in the crystal under the effect of uniaxial loading F >= 10 kG/mm/sup 3/ at 6 K. Dislocations during their movement in the sliding planes produce specific defects in the crystalline lattice which, being the effective centres of irradiation recombination with characteristic radiation spectrum are presented in the form of luminescent traces which passed through the dislocation crystal. A group of symmetry of these centers is determined by means of piesospectroscopic investigations of the obtained radiation spectrum.

  12. Cadmium and renal cancer

    International Nuclear Information System (INIS)

    Il'yasova, Dora; Schwartz, Gary G.

    2005-01-01

    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

  13. Isolation, identification and cadmium adsorption of a high cadmium ...

    African Journals Online (AJOL)

    GREGORY

    2010-09-27

    Sep 27, 2010 ... 1School of Minerals Processing and Bioengineering, Central South University, Changsha, ... Cadmium is a non-essential ... (1994) reported that cadmium might interact ... uptake of cadmium, lead and mercury (Svecova et al.,.

  14. Harnessing Sun’s Energy with Quantum Dots Based Next Generation Solar Cell

    Science.gov (United States)

    Halim, Mohammad A.

    2012-01-01

    Our energy consumption relies heavily on the three components of fossil fuels (oil, natural gas and coal) and nearly 83% of our current energy is consumed from those sources. The use of fossil fuels, however, has been viewed as a major environmental threat because of their substantial contribution to greenhouse gases which are responsible for increasing the global average temperature. Last four decades, scientists have been searching for alternative sources of energy which need to be environmentally clean, efficient, cost-effective, renewable, and sustainable. One of the promising sustainable sources of energy can be achieved by harnessing sun energy through silicon wafer, organic polymer, inorganic dye, and quantum dots based solar cells. Among them, quantum dots have an exceptional property in that they can excite multiple electrons using only one photon. These dots can easily be synthesized, processed in solution, and incorporated into solar cell application. Interestingly, the quantum dots solar cells can exceed the Shockley-Queisser limit; however, it is a great challenge for other solar cell materials to exceed the limit. Theoretically, the quantum dots solar cell can boost the power conversion efficiency up to 66% and even higher to 80%. Moreover, in changing the size of the quantum dots one can utilize the Sun’s broad spectrum of visible and infrared ranges. This review briefly overviews the present performance of different materials-based solar cells including silicon wafer, dye-sensitized, and organic solar cells. In addition, recent advances of the quantum dots based solar cells which utilize cadmium sulfide/selenide, lead sulfide/selenide, and new carbon dots as light harvesting materials has been reviewed. A future outlook is sketched as to how one could improve the efficiency up to 10% from the current highest efficiency of 6.6%. PMID:28348320

  15. Harnessing Sun's Energy with Quantum Dots Based Next Generation Solar Cell.

    Science.gov (United States)

    Halim, Mohammad A

    2012-12-27

    Our energy consumption relies heavily on the three components of fossil fuels (oil, natural gas and coal) and nearly 83% of our current energy is consumed from those sources. The use of fossil fuels, however, has been viewed as a major environmental threat because of their substantial contribution to greenhouse gases which are responsible for increasing the global average temperature. Last four decades, scientists have been searching for alternative sources of energy which need to be environmentally clean, efficient, cost-effective, renewable, and sustainable. One of the promising sustainable sources of energy can be achieved by harnessing sun energy through silicon wafer, organic polymer, inorganic dye, and quantum dots based solar cells. Among them, quantum dots have an exceptional property in that they can excite multiple electrons using only one photon. These dots can easily be synthesized, processed in solution, and incorporated into solar cell application. Interestingly, the quantum dots solar cells can exceed the Shockley - Queisser limit; however, it is a great challenge for other solar cell materials to exceed the limit. Theoretically, the quantum dots solar cell can boost the power conversion efficiency up to 66% and even higher to 80%. Moreover, in changing the size of the quantum dots one can utilize the Sun's broad spectrum of visible and infrared ranges. This review briefly overviews the present performance of different materials-based solar cells including silicon wafer, dye-sensitized, and organic solar cells. In addition, recent advances of the quantum dots based solar cells which utilize cadmium sulfide/selenide, lead sulfide/selenide, and new carbon dots as light harvesting materials has been reviewed. A future outlook is sketched as to how one could improve the efficiency up to 10% from the current highest efficiency of 6.6%.

  16. The molecular beam epitaxy growth and characterization of zinc cadmium selenide/zinc cadmium magnesium selenide-indium phosphide quantum cascade structures for operation in the 3 - 5 um range

    Science.gov (United States)

    Charles, William O.

    The quantum cascade (QC) laser has captured the interest of researchers for almost three decades. In the early stages, researchers were very interested in proving the QC concept1 proposed by Kazarinov and Suris in 1971. This new concept gave researchers hope that very bulky energy inefficient infra-red (IR) lasers would be replaced with ones that are very compact, tunable and portable. Since the proposal of the QC laser concept and its first demonstration by researchers at Bell Laboratories2 in 1994, this technology has progressed to the point where it is now finding commercial applications in a variety of areas such as military counter measures, free space telecommunications, infra-red imaging and chemical spectroscopy.3-5 The success of this technology can be attributed to the coming of age of the techniques of molecular beam epitaxy (MBE) semiconductor growth and bandgap engineering. 6,7 Using MBE technology, the temperature of the source material can be stabilized by making use of a combination of proportional integral derivative (PID) controllers and thermocouple feedbacks. As a result, the material flux from the effusion cells can achieve stability better than (+/-) 1%. This flux stability together with a well-developed computer controlled shuttering mechanism make it possible to grow multi-quantum well (MQW) structures with excellent layer thickness precision (mono-layer scale) and interface quality. This stringent control of material flux is also a tool that is used by MBE growers to vary the material compositions for the growth of lattice matched and strain compensated QC structures. Today, MBE stands out as one of the premier methods for growing high performing QC lasers. The first successful demonstration of a QC laser2 was done using the InGaAs/InAlAs-InP material system. This demonstration was then repeated a few years later using GaAs/AlGaAs-InP.8 These III-V material systems were extensively studied to establish their material parameters. Given that

  17. The mechanism of electrodeposition of bismuth sulfide and cadmium sulfide from dimethylsulfoxide and diethylene glycol solution

    International Nuclear Information System (INIS)

    Gilbert, C.M.; Baranski, A.S.; Fawcett, W.R.

    1985-01-01

    The kinetics of the electrodeposition of Bi 2 S 3 on an electrode covered with a coherent layer of Bi 2 S 3 was examined by analysis of the Tafel plots for different solution compositions and at different temperatures in two nonaqueous solvents, dimethylsulfoxide (DMSO) and diethylene glycol (DEG). The results were compared with those obtained for the electrodeposition of CdS on CdS under similar conditions. In both cases, it was found that the rate-determining step was an irreversible electron transfer. The rate of the reaction was independent of the metal ion concentration, but electrochemical orders with respect to S 8 of 0.7 in DMSO and 1.0 in DEG were found. Several mechanisms explaining these results are proposed and discussed

  18. Imaging pancreatic cancer using bioconjugated InP quantum dots.

    Science.gov (United States)

    Yong, Ken-Tye; Ding, Hong; Roy, Indrajit; Law, Wing-Cheung; Bergey, Earl J; Maitra, Anirban; Prasad, Paras N

    2009-03-24

    In this paper, we report the successful use of non-cadmium-based quantum dots (QDs) as highly efficient and nontoxic optical probes for imaging live pancreatic cancer cells. Indium phosphide (core)-zinc sulfide (shell), or InP/ZnS, QDs with high quality and bright luminescence were prepared by a hot colloidal synthesis method in nonaqueous media. The surfaces of these QDs were then functionalized with mercaptosuccinic acid to make them highly dispersible in aqueous media. Further bioconjugation with pancreatic cancer specific monoclonal antibodies, such as anticlaudin 4 and antiprostate stem cell antigen (anti-PSCA), to the functionalized InP/ZnS QDs, allowed specific in vitro targeting of pancreatic cancer cell lines (both immortalized and low passage ones). The receptor-mediated delivery of the bioconjugates was further confirmed by the observation of poor in vitro targeting in nonpancreatic cancer based cell lines which are negative for the claudin-4-receptor. These observations suggest the immense potential of InP/ZnS QDs as non-cadmium-based safe and efficient optical imaging nanoprobes in diagnostic imaging, particularly for early detection of cancer.

  19. Subcellular partitioning kinetics, metallothionein response and oxidative damage in the marine mussel Mytilus galloprovincialis exposed to cadmium-based quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Thiago Lopes [CIMA, Faculty of Science and Technology, University of Algarve, Campus de Gambelas, 8005-139 Faro (Portugal); Gomes, Tânia [CIMA, Faculty of Science and Technology, University of Algarve, Campus de Gambelas, 8005-139 Faro (Portugal); Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, NO-0349 Oslo (Norway); Durigon, Emerson Giuliani [CIMA, Faculty of Science and Technology, University of Algarve, Campus de Gambelas, 8005-139 Faro (Portugal); Bebianno, Maria João, E-mail: mbebian@ualg.pt [CIMA, Faculty of Science and Technology, University of Algarve, Campus de Gambelas, 8005-139 Faro (Portugal)

    2016-06-01

    The environmental health impact of metal-based nanomaterials is of emerging concern, but their metabolism and detoxification pathways in marine bioindicator species remain unclear. This study investigated the role of subcellular partitioning kinetics, metallothioneins (MTs) response and oxidative damage (lipid peroxidation – LPO) in the marine mussel Mytilus galloprovincialis exposed to CdTe quantum dots (QDs) in comparison with its dissolved counterpart. Mussels were exposed to QDs and dissolved Cd for 21 days at 10 μg Cd L{sup −1} followed by a 50 days depuration. Higher Cd concentrations were detected in fractions containing mitochondria, nucleus and lysosomes, suggesting potential subcellular targets of QDs toxicity in mussel tissues. Tissue specific metabolism patterns were observed in mussels exposed to both Cd forms. Although MT levels were directly associated with Cd in both forms, QDs subcellular partitioning is linked to biologically active metal (BAM), but no increase in LPO occurred, while in the case of dissolved Cd levels are in the biologically detoxified metal (BDM) form, indicating nano-specific effects. Mussel gills showed lower detoxification capability of QDs, while the digestive gland is the major tissue for storage and detoxification of both Cd forms. Both mussel tissues were unable to completely eliminate the Cd accumulated in the QDs form (estimated half-life time > 50 days), highlighting the potential source of Cd and QDs toxicity for human and environmental health. Results indicate tissue specific metabolism patterns and nano-specific effects in marine mussel exposed to QDs. - Highlights: • Subcellular partitioning and MT response are Cd form, tissue and time dependent. • Tissue specific metabolism of Cd-based quantum dots (QDs) in marine mussels. • QDs are slower biologically detoxified when compared to dissolved Cd. • Subcellular partitioning and biomarker responses indicate nano-specific effects. • Subcellular

  20. Enhanced Performance of DSSCs Based on the Insertion Energy Level of CdS Quantum Dots

    Directory of Open Access Journals (Sweden)

    Xiaoping Zou

    2014-01-01

    Full Text Available Cadmium sulfide (CdS quantum dots (QDs are assembled onto the TiO2 films by chemical bath deposition method (CBD. And the QDs size is controlled by the times of CBD cycles. They are characterized by UV-visible absorption. To avoid the photo corrosion and electrolyte corrosion, CdS and N719 are sequentially assembled onto the nanocrystalline TiO2 films to prepare a CdS/N719 cosensitized photo electrode for the dye-sensitized solar cells. In the structure of TiO2/CdS/N719 electrode, the reorganization of energy levels between CdS and N719 forms a stepwise structure of band-edge levels which is advantageous to the electron injection and hole recovery of CdS and N719 QDs. The open circuit voltage (Voc, short circuit current density (Jsc, and efficiency are increased.

  1. Zinc and cadmium monosalicylates

    International Nuclear Information System (INIS)

    Kharitonov, Yu.Ya.; Tujebakhova, Z.K.

    1984-01-01

    Zinc and cadmium monosalicylates of the composition MSal, where M-Zn or Cd, Sal - twice deprotonated residue of salicylic acid O-HOC 6 H 4 COOH (H 2 Sal), are singled out and characterized. When studying thermograms, thermogravigrams, IR absorption spectra, roentgenograms of cadmium salicylate compounds (Cd(OC 6 H 4 COO) and products of their thepmal transformations, the processes of thermal decomposition of the compounds have been characterized. The process of cadmium monosalicylate decomposition takes place in one stage. Complete loss of salicylate acido group occurs in the range of 320-460 deg. At this decomposition stage cadmium oxide is formed. A supposition is made that cadmium complex has tetrahedral configuration, at that, each salicylate group plays the role of tetradentate-bridge ligand. The compound evidently has a polymer structure

  2. Determination of cadmium selenide nonstoichiometry

    International Nuclear Information System (INIS)

    Brezhnev, V.Yu.; Kharif, Ya.L.; Kovtunenko, P.V.

    1986-01-01

    Physicochemical method of determination of cadmium selenide nonstoichiometry is developed. The method nature consists in the fact, that under definite conditions dissolved cadmium is extracted from crystals to a vapor phase and then is determined in it using the photocolorimetric method. Cadmium solubility in CdSe crystal is calculated from known CdSe mass and amount of separated cadmium. The lower boundary of determined contents constitutes 1x10 -5 % mol at sample of cadmium selenide 10 g

  3. The vapour pressures over saturated aqueous solutions of cadmium chloride, cadmium bromide, cadmium iodide, cadmium nitrate, and cadmium sulphate

    International Nuclear Information System (INIS)

    Apelblat, Alexander; Korin, Eli

    2007-01-01

    Vapour pressures of water over saturated solutions of cadmium salts (chloride, bromide, iodide, nitrate, and sulphate) were determined over the temperature range 280 K to 322 K and compared with the literature data. The vapour pressures determined were used to obtain the water activities, osmotic coefficients and the molar enthalpies of vaporization in the (cadmium salt + water) systems

  4. The vapour pressures over saturated aqueous solutions of cadmium chloride, cadmium bromide, cadmium iodide, cadmium nitrate, and cadmium sulphate

    Energy Technology Data Exchange (ETDEWEB)

    Apelblat, Alexander [Department of Chemical Engineering, Ben Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105 (Israel)]. E-mail: apelblat@bgu.ac.il; Korin, Eli [Department of Chemical Engineering, Ben Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105 (Israel)

    2007-07-15

    Vapour pressures of water over saturated solutions of cadmium salts (chloride, bromide, iodide, nitrate, and sulphate) were determined over the temperature range 280 K to 322 K and compared with the literature data. The vapour pressures determined were used to obtain the water activities, osmotic coefficients and the molar enthalpies of vaporization in the (cadmium salt + water) systems.

  5. Calcium enhances cadmium tolerance and decreases cadmium ...

    African Journals Online (AJOL)

    Yomi

    2012-04-26

    Apr 26, 2012 ... concentrations alleviated the toxic effect of cadmium on the growth and water status of lettuce plants. The three lettuce varieties ... electroplating, in batteries, in electrical conductors, in the manufacture of alloys ..... Handbook on the Toxicology of Metals, Third edition, Salt Lake City, UT: Acad. Press. Österås ...

  6. Histopathological assessment and inflammatory response in the digestive gland of marine mussel Mytilus galloprovincialis exposed to cadmium-based quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Thiago Lopes [CIMA, Faculty of Science and Technology, University of Algarve, Campus de Gambelas, 8005-139 Faro (Portugal); Laboratory of Cellular Behavior, Biological Sciences Institute, Federal University of Goiás, Goiânia, Goiás (Brazil); Sabóia-Morais, Simone Maria Teixeira [Laboratory of Cellular Behavior, Biological Sciences Institute, Federal University of Goiás, Goiânia, Goiás (Brazil); Bebianno, Maria João, E-mail: mbebian@ualg.pt [CIMA, Faculty of Science and Technology, University of Algarve, Campus de Gambelas, 8005-139 Faro (Portugal)

    2016-08-15

    Highlights: • Digestive gland of marine mussels is target for Cd-based QDs toxicity. • Both Cd forms increase the frequency of atrophic digestive tubules in a time dependent pattern. • QDs induce higher inflammatory responses when compared to dissolved Cd. • Multiparametric tissue-levels biomarkers show distinct mode of action in the digestive gland. - Abstract: Although tissue-level biomarkers have been widely applied in environmental toxicology studies, the knowledge using this approach in marine invertebrates exposed to engineered nanomaterials (ENMs) remains limited. This study investigated histopathological alterations and inflammatory responses induced by Cd-based quantum dots (QDs), in comparison with their dissolved counterparts, in the marine mussel Mytilus galloprovincialis. Mussels were exposed to CdTe QDs and dissolved Cd at the same concentration (10 μg Cd L{sup −1}) for 14 days and a total of 15 histopathological alterations and 17 histomorphometric parameters were analysed in the digestive gland along with the determination of histopathological condition indices (I{sub h}). A multivariate analysis showed that the mussel response to QDs was more related to exposure time, inflammatory conditions (frequency of haemocytic infiltration and granulocytomas) and changes of cell-type composition (especially the rate between basophilic and digestive cells) when compared to dissolved Cd, while the response to dissolved Cd was associated with histomorphometric parameters of the epithelium and lumen of digestive tubules and increase of the atrophic tubule frequency. Both Cd forms induced higher I{sub h} compared to unexposed mussels indicating a significant decrease in the health status of digestive gland in a Cd form and time-dependent pattern. Results indicate that the multiparametric tissue-level biomarkers in the digestive gland provide a suitable approach to assess the ecotoxicity and mode of action of metal-based ENMs in marine bivalves.

  7. Preparation of strongly fluorescent silica nanoparticles of polyelectrolyte-protected cadmium telluride quantum dots and their application to cell toxicity and imaging

    International Nuclear Information System (INIS)

    Tang Jianhua; Xie Lian; Zhang Bin; Qiu Ting; Qi Bin; Xie Hongping

    2012-01-01

    Graphical abstract: The staining effect of the control group (a), QDs-SiO 2 (b) and QDs-PDADMAC-SiO 2 (c). Highlights: ► The fluorescence intensity of QDs-PDADMAC-SiO 2 is stronger than that of QDs-SiO 2 . ► The fluorescence stability of QDs-PDADMAC-SiO 2 is better than that of QDs-SiO 2 . ► The cytotoxicity of QDs-PDADMAC-SiO 2 was lower than that of QDs-SiO 2 ► The staining effect of QDs-PDADMAC-SiO 2 was much better than that of QDs-SiO 2 . - Abstract: Based on the polyelectrolyte-protected CdTe quantum dots (QDs), which were prepared by self-assembling of QDs and poly-diallyldimethylammonium chloride (PDADMAC) in the help of electrostatic attraction, the strong fluorescence silica nanoparticles (QDs-PDADMAC-SiO 2 ) have been prepared via a water-in-oil reverse microemulsion method. Transmission electron microscopy and Zeta potential analysis were used to characterize the as-prepared nanoparticles. All of the particles were almost spherical and there is a uniform distribution of the particle size with the average diameter about 25 nm. There is a large Zeta potential of −35.07 mV which is necessary for good monodispersity of nanoparticles solution. As compared with the QDs coated by SiO 2 (QDs-SiO 2 ), the QDs-PDADMAC-SiO 2 nanoparticles have much stronger fluorescence, and their fluorescence stability could be obviously improved. Moreover, QDs-PDADMAC-SiO 2 exhibits good biological compatibility which promotes their application in cellular imaging.

  8. Simultaneous determination of oxygen and cadmium in cadmium and cadmium compounds

    International Nuclear Information System (INIS)

    Imaeda, K.; Kuriki, T.; Ohsawa, K.; Ishii, Y.

    1977-01-01

    Cadmium and its compounds were analysed for oxygen and cadmium by a modification of the Schutze-Unterzaucher method. Oxygen in some compounds such as cadmium oxide, nitrate and sulphate could not be determined by the usual method. The method of adding carbon was employed for the determination of total oxygen. Total oxygen could be determined by the addition of 5 mg of carbon to a sample boat and heating at 950 0 . The determination was also carried out by addition of naphthalene (2 mg). It was found that the cadmium powder and cadmium flake used contained ca. 1 and 0.15% oxygen, respectively. Oxygen and cadmium in cadmium and its compounds were simultaneously determined by the addition of 2 mg of naphthalene. Cadmium was determined colorimetrically by use of glyoxal-bis-(2-hydroxyanil). Oxygen and cadmium in the samples could be determined simultaneously with an average error of -0.02 and -0.22%, respectively. (author)

  9. Mechanochemical reduction of copper sulfide

    DEFF Research Database (Denmark)

    Balaz, P.; Takacs, L.; Jiang, Jianzhong

    2002-01-01

    The mechanochemical reduction of copper sulfide with iron was induced in a Fritsch P-6 planetary mill, using WC vial filled with argon and WC balls. Samples milled for specific intervals were analyzed by XRD and Mossbauer spectroscopy. Most of the reaction takes place during the first 10 min...... of milling and only FeS and Cu are found after 60 min. The main chemical process is accompanied by phase transformations of the sulfide phases as a result of milling. Djurleite partially transformed to chalcocite and a tetragonal copper sulfide phase before reduction. The cubic modification of FeS was formed...... first, transforming to hexagonal during the later stages of the process. The formation of off-stoichiometric phases and the release of some elemental sulfur by copper sulfide are also probable....

  10. LIGNOCELLULOSE NANOCOMPOSITE CONTAINING COPPER SULFIDE

    OpenAIRE

    Sanchi Nenkova; Peter Velev; Mirela Dragnevska; Diyana Nikolova; Kiril Dimitrov

    2011-01-01

    Copper sulfide-containing lignocellulose nanocomposites with improved electroconductivity were obtained. Two methods for preparing the copper sulfide lignocellulose nanocomposites were developed. An optimization of the parameters for obtaining of the nanocomposites with respect to obtaining improved electroconductivity, economy, and lower quantities and concentration of copper and sulfur ions in waste waters was conducted. The mechanisms and schemes of delaying and subsequent connection of co...

  11. Luminescence in Sulfides: A Rich History and a Bright Future

    Directory of Open Access Journals (Sweden)

    Philippe F. Smet

    2010-04-01

    Full Text Available Sulfide-based luminescent materials have attracted a lot of attention for a wide range of photo-, cathodo- and electroluminescent applications. Upon doping with Ce3+ and Eu2+, the luminescence can be varied over the entire visible region by appropriately choosing the composition of the sulfide host. Main application areas are flat panel displays based on thin film electroluminescence, field emission displays and ZnS-based powder electroluminescence for backlights. For these applications, special attention is given to BaAl2S4:Eu, ZnS:Mn and ZnS:Cu. Recently, sulfide materials have regained interest due to their ability (in contrast to oxide materials to provide a broad band, Eu2+-based red emission for use as a color conversion material in white-light emitting diodes (LEDs. The potential application of rare-earth doped binary alkaline-earth sulfides, like CaS and SrS, thiogallates, thioaluminates and thiosilicates as conversion phosphors is discussed. Finally, this review concludes with the size-dependent luminescence in intrinsic colloidal quantum dots like PbS and CdS, and with the luminescence in doped nanoparticles.

  12. Flux of Cadmium through Euphausiids

    International Nuclear Information System (INIS)

    Benayoun, G.; Fowler, S.W.; Oregioni, B.

    1976-01-01

    Flux of the heavy metal cadmium through the euphausiid Meganyctiphanes norvegica was examined. Radiotracer experiments showed that cadmium can be accumulated either directly from water or through the food chain. When comparing equilibrium cadmium concentration factors based on stable element measurements with those obtained from radiotracer experiments, it is evident that exchange between cadmium in the water and that in euphausiid tissue is a relatively slow process, indicating that, in the long term, ingestion of cadmium will probably be the more important route for the accumulation of this metal. Approximately 10% of cadmium ingested by euphausiids was incorporated into internal tissues when the food source was radioactive Artemia. After 1 month cadmium, accumulated directly from water, was found to be most concentrated in the viscera with lesser amounts in eyes, exoskeleton and muscle, respectively. Use of a simple model, based on the assumption that cadmium taken in by the organism must equal cadmium released plus that accumulated in tissue, allowed assessment of the relative importance of various metabolic parameters in controlling the cadmium flux through euphausiids. Fecal pellets, due to their relatively high rate of production and high cadmium content, accounted for 84% of the total cadmium flux through M. norvegica. Comparisons of stable cadmium concentrations in natural euphausiid food and the organism's resultant fecal pellets indicate that the cadmium concentration in ingested material was increased nearly 5-fold during its passage through the euphausiid. From comparisons of all routes by which cadmium can be released from M. norvegica to the water column, it is concluded that fecal pellet deposition represents the principal mechanism effecting the downward vertical transport of cadmium by this species. (author)

  13. Chlorination leaching of cadmium

    International Nuclear Information System (INIS)

    Lach, E.; Pajak, I.; Bojanowska, A.

    1978-01-01

    The results of the investigations on chlorination leaching of cadmium from dust coming from dry dust collector of sinter belt, that is leaching with water saturated with gaseous chlorine and leaching with solutions of ammonium chloride and sodium chloride were given. The optimum conditions for these processes were established. It was found, that the method of leaching in the presence of gaseous chlorine is more effective, as it allows to report into the solution over 90% cadmium contained in dust. Owing to technical difficulties, environmental protection and safety conditions more advantageous seems to be the use as leaching agent of the ammonium chloride solutions. When applying 20% NH 4 Cl and temperature of 60 0 C, the time of 2 hours and the ratio of solid to liquid of 1:5, 70% cadmium contained in the dust can be reported into the solution. (auth.)

  14. A Reaction Involving Oxygen and Metal Sulfides.

    Science.gov (United States)

    Hill, William D. Jr.

    1986-01-01

    Describes a procedure for oxygen generation by thermal decomposition of potassium chlorate in presence of manganese dioxide, reacted with various sulfides. Provides a table of sample product yields for various sulfides. (JM)

  15. Sulfide-conducting solid electrolytes

    International Nuclear Information System (INIS)

    Kalinina, L.A.; Shirokova, G.I.; Murin, I.V.; Ushakova, Yu.N.; Fominykh, E.G.; Lyalina, M.Yu.

    2000-01-01

    Feasibility of sulfide transfer in phases on the basis of BaZrS 3 and MLn 2 S 4 ( M = Ca, Ba; Ln = La, Y, Tm, Nd, Sm, Pr) is considered. Solid solution regions on the basis of ternary compounds are determined. Systematic study of the phases is carried out making use of the methods of conductometry, emf in chemical concentration chains without/with transfer, potentiostatic chronoamperometry. Possible mechanism of defect formation during successive alloying of ternary sulfides by binary ones in suggested [ru

  16. Cadmium plating replacements

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, M.J.; Groshart, E.C.

    1995-03-01

    The Boeing Company has been searching for replacements to cadmium plate. Two alloy plating systems seem close to meeting the needs of a cadmium replacement. The two alloys, zinc-nickel and tin-zinc are from alloy plating baths; both baths are neutral pH. The alloys meet the requirements for salt fog corrosion resistance, and both alloys excel as a paint base. Currently, tests are being performed on standard fasteners to compare zinc-nickel and tin-zinc on threaded hardware where cadmium is heavily used. The Hydrogen embrittlement propensity of the zinc-nickel bath has been tested, and just beginning for the tin-zinc bath. Another area of interest is the electrical properties on aluminum for tin-zinc and will be discussed. The zinc-nickel alloy plating bath is in production in Boeing Commercial Airplane Group for non-critical low strength steels. The outlook is promising that these two coatings will help The Boeing Company significantly reduce its dependence on cadmium plating.

  17. Cadmium: The deformed metal

    Energy Technology Data Exchange (ETDEWEB)

    Stubbs, R L [Cadmium Association, London (UK)

    1979-03-01

    The paper, which is a somewhat abridged version of the introductory paper of the 2nd International Cadmium Conference in Cannes on February 6 to 8, 1979, outlines the present trends in production, reserves, consumption, world trade, prices, and cost. Due to the lack of statistics on the USSR and other socialist countries, the review is limited to the non-socialist world.

  18. zinc, chromium, cadmium

    African Journals Online (AJOL)

    2016-06-30

    Jun 30, 2016 ... Cadmium also causes destruction of the immune system, thus, predisposes the consumer to infectious diseases like tuberculosis (Khan et al., 2008). ... years, sputum specimens positive for acid-fast bacilli by microscopy and clinical and radiographic abnormalities consistent with pulmonary tuberculosis.

  19. Nanostructured metal sulfides for energy storage

    Science.gov (United States)

    Rui, Xianhong; Tan, Huiteng; Yan, Qingyu

    2014-08-01

    Advanced electrodes with a high energy density at high power are urgently needed for high-performance energy storage devices, including lithium-ion batteries (LIBs) and supercapacitors (SCs), to fulfil the requirements of future electrochemical power sources for applications such as in hybrid electric/plug-in-hybrid (HEV/PHEV) vehicles. Metal sulfides with unique physical and chemical properties, as well as high specific capacity/capacitance, which are typically multiple times higher than that of the carbon/graphite-based materials, are currently studied as promising electrode materials. However, the implementation of these sulfide electrodes in practical applications is hindered by their inferior rate performance and cycling stability. Nanostructures offering the advantages of high surface-to-volume ratios, favourable transport properties, and high freedom for the volume change upon ion insertion/extraction and other reactions, present an opportunity to build next-generation LIBs and SCs. Thus, the development of novel concepts in material research to achieve new nanostructures paves the way for improved electrochemical performance. Herein, we summarize recent advances in nanostructured metal sulfides, such as iron sulfides, copper sulfides, cobalt sulfides, nickel sulfides, manganese sulfides, molybdenum sulfides, tin sulfides, with zero-, one-, two-, and three-dimensional morphologies for LIB and SC applications. In addition, the recently emerged concept of incorporating conductive matrices, especially graphene, with metal sulfide nanomaterials will also be highlighted. Finally, some remarks are made on the challenges and perspectives for the future development of metal sulfide-based LIB and SC devices.

  20. 30 CFR 250.504 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.504 Section 250.504... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Well-Completion Operations § 250.504 Hydrogen sulfide. When a well-completion operation is conducted in zones known to contain hydrogen sulfide (H2S) or in...

  1. 30 CFR 250.808 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.808 Section 250.808... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Production Safety Systems § 250.808 Hydrogen sulfide. Production operations in zones known to contain hydrogen sulfide (H2S) or in zones where the presence of H2S...

  2. 30 CFR 250.604 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.604 Section 250.604... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Well-Workover Operations § 250.604 Hydrogen sulfide. When a well-workover operation is conducted in zones known to contain hydrogen sulfide (H2S) or in...

  3. Molecular basis of cadmium toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Nath, R; Prasad, R; Palinal, V K; Chopra, R K

    1984-01-01

    Cadmium has been shown to manifest its toxicity in human and animals by mainly accumulating in almost all of the organs. The kidney is the main target organ where it is concentrated mainly in the cortex. Environmental exposure of cadmium occurs via food, occupational industries, terrestrial and aquatic ecosystem. At molecular level, cadmium interferes with the utilization of essential metals e.g. Ca, Zn, Se, Cr and Fe and deficiencies of these essential metals including protein and vitamins, exaggerate cadmium toxicity, due to its increased absorption through the gut and greater retention in different organs as metallothionein (Cd-Mt). Cadmium transport, across the intestinal and renal brush border membrane vesicles, is carrier mediated and it competes with zinc and calcium. It has been postulated that cadmium shares the same transport system. Cadmium inhibits protein synthesis, carbohydrate metabolism and drug metabolizing enzymes in liver of animals. Chronic environmental exposure of cadmium produces hypertension in experimental animals. Functional changes accompanying cadmium nephropathy include low molecular weight proteinuria which is of tubular origin associated with excess excretion of proteins such as beta 2 microglobulin, metallothionein and high molecular weight proteinuria of glomerular origin (excretion of proteins such as albumin IgG, transferrin etc.). Recent data has shown that metallothionein is more nephrotoxic to animals. Cadmium is also toxic to central nervous system. It causes an alterations of cellular functions in lungs. Cadmium affects both humoral and cell mediated immune response in animals. Cadmium induces metallothionein in liver and kidney but under certain nutritional deficiencies like protein-calorie malnutrition and calcium deficiency, enhanced induction and greater accumulation of cadmium metallothionein has been observed.

  4. STUDY OF HYDROGEN SULFIDE REMOVAL FROM GROUNDWATER

    Directory of Open Access Journals (Sweden)

    T. Lupascu

    2013-06-01

    Full Text Available The process of the hydrogen sulfide removal from the underground water of the Hancesti town has been investigated. By oxygen bubbling through the water containing hydrogen sulfide, from the Hancesti well tube, sulfur is deposited in the porous structure of studied catalysts, which decreases their catalytic activity. Concomitantly, the process of adsorption / oxidation of hydrogen sulfide to sulfate take place. The kinetic research of the hydrogen sulfide removal from the Hancesti underground water, after its treatment by hydrogen peroxide, proves greater efficiency than in the case of modified carbonic adsorbents. As a result of used treatment, hydrogen sulfide is completely oxidized to sulfates

  5. Er2S[SiO4]: An erbium sulfide ortho-oxosilicate with unusual sulfide anion coordination

    International Nuclear Information System (INIS)

    Hartenbach, Ingo; Lauxmann, Petra; Schleid, Thomas

    2004-01-01

    During the reaction of cadmium sulfide with erbium and sulfur in evacuated silica ampoules pink lath-shaped crystals of Er 2 S[SiO 4 ] occur as by-product which were characterized by X-ray single crystal structure analysis. The title compound crystallizes orthorhombically in the space group Cmce (a = 1070.02(8), b = 1235.48(9), c = 683.64(6) pm) with eight formula units per unit cell. Besides isolated ortho-oxosilicate units [SiO 4 ] 4- , the crystal structure contains two crystallographically independent Er 3+ cations which are both eightfold coordinated by six oxygen and two sulfur atoms. The sulfide anions are surrounded by four erbium cations each in the shape of very distorted tetrahedra. These excentric [SEr 4 ] 10+ tetrahedra build up layers according to 2 ∞ [SEr 4/2 ] 4+ by vertex- and edge-connection. They are piled parallel to (010) and separated by the isolated ortho-oxosilicate tetrahedra. (Abstract Copyright [2004], Wiley Periodicals, Inc.) [de

  6. Biological interactions of quantum dot nanoparticles in skin and in human epidermal keratinocytes

    International Nuclear Information System (INIS)

    Zhang, Leshuai W.; Yu, William W.; Colvin, Vicki L.; Monteiro-Riviere, Nancy A.

    2008-01-01

    Quantum dots nanoparticles have novel optical properties for biomedical applications and electronics, but little is known about their skin permeability and interaction with cells. QD621 are nail-shaped nanoparticles that contain a cadmium/selenide core with a cadmium sulfide shell coated with polyethylene glycol (PEG) and are soluble in water. QD were topically applied to porcine skin flow-through diffusion cells to assess penetration at 1 μM, 2 μM and 10 μM for 24 h. QD were also studied in human epidermal keratinocytes (HEK) to determine cellular uptake, cytotoxicity and inflammatory potential. Confocal microscopy depicted the penetration of QD621 through the uppermost stratum corneum (SC) layers of the epidermis and fluorescence was found primarily in the SC and near hair follicles. QD were found in the intercellular lipid bilayers of the SC by transmission electron microscopy (TEM). Inductively coupled plasma-optical emission spectroscopy (ICP-OES) analysis for cadmium (Cd) and fluorescence for QD both did not detect Cd nor fluorescence signal in the perfusate at any time point or concentration. In HEK, viability decreased significantly (p < 0.05) from 1.25 nM to 10nM after 24 h and 48 h. There was a significant increase in IL-6 at 1.25 nM to 10 nM, while IL-8 increased from 2.5nM to 10nM after 24 h and 48 h. TEM of HEK treated with 10 nM of QD621 at 24 h depicted QD in cytoplasmic vacuoles and at the periphery of the cell membranes. These results indicate that porcine skin penetration of QD621 is minimal and limited primarily to the outer SC layers, yet if the skin were damaged allowing direct QD exposure to skin or keratinocytes, an inflammatory response could be initiated

  7. Cadmium in Sweden - environmental risks

    Energy Technology Data Exchange (ETDEWEB)

    Parkman, H; Iverfeldt, Aa [Swedish Environmental Research Inst. (Sweden); Borg, H; Lithner, G [Stockholm Univ. (Sweden). Inst. for Applied Environmental Research

    1998-03-01

    This report aims at assessing possible effects of cadmium in the Swedish environment. Swedish soils and soft freshwater systems are, due to a generally poor buffering capacity, severely affected by acidification. In addition, the low salinity in the Baltic Sea imply a naturally poor organism structure, with some important organisms living close to their limit of physiological tolerance. Cadmium in soils is mobilized at low pH, and the availability and toxicity of cadmium in marine systems are enhanced at low salinity. The Swedish environment is therefore extra vulnerable to cadmium pollution. The average concentrations of cadmium in the forest mor layers, agricultural soils, and fresh-waters in Sweden are enhanced compared to `back-ground concentrations`, with a general increasing trend from the north to the south-west, indicating strong impact of atmospheric deposition of cadmium originating from the central parts of Europe. In Swedish sea water, total cadmium concentrations, and the fraction of bio-available `free` cadmium, generally increases with decreasing salinity. Decreased emissions of cadmium to the environment have led to decreasing atmospheric deposition during the last decade. The net accumulation of cadmium in the forest mor layer has stopped, and even started to decrease. In northern Sweden, this is due to the decreased deposition, but in southern Sweden the main reason is increased leakage of cadmium from the topsoil as a consequence of acidification. As a result, cadmium in the Swedish environments is undergoing an extended redistribution between different soil compartments, and from the soils to the aquatic systems. 90 refs, 23 figs, 2 tabs. With 3 page summary in Swedish

  8. Cadmium: The deformed metal

    International Nuclear Information System (INIS)

    Stubbs, R.L.

    1979-01-01

    The paper, which is a somewhat abridged version of the introductory paper of the 2nd International Cadmium Conference in Cannes on February 6 to 8, 1979, outlines the present trends in production, reserves, consumption, world trade, prices, and cost. Due to the lack of statistics on the USSR and other socialist countries, the review is limited to the non-socialist world. (orig./IHOE) [de

  9. Effects of Self-Assembled Monolayers on Solid-State CdS Quantum Dot Sensitized Solar Cells

    KAUST Repository

    Ardalan, Pendar; Brennan, Thomas P.; Lee, Han-Bo-Ram; Bakke, Jonathan R.; Ding, I-Kang; McGehee, Michael D.; Bent, Stacey F.

    2011-01-01

    Quantum dot sensitized solar cells (QDSSCs) are of interest for solar energy conversion because of their tunable band gap and promise of stable, low-cost performance. We have investigated the effects of self-assembled monolayers (SAMs) with phosphonic acid headgroups on the bonding and performance of cadmium sulfide (CdS) solid-state QDSSCs. CdS quantum dots ∼2 to ∼6 nm in diameter were grown on SAM-passivated planar or nanostructured TiO 2 surfaces by successive ionic layer adsorption and reaction (SILAR), and photovoltaic devices were fabricated with spiro-OMeTAD as the solid-state hole conductor. X-ray photoelectron spectroscopy, Auger electron spectroscopy, ultraviolet-visible spectroscopy, scanning electron microscopy, transmission electron microscopy, water contact angle measurements, ellipsometry, and electrical measurements were employed to characterize the materials and the resulting device performance. The data indicate that the nature of the SAM tailgroup does not significantly affect the uptake of CdS quantum dots on TiO2 nor their optical properties, but the presence of the SAM does have a significant effect on the photovoltaic device performance. Interestingly, we observe up to ∼3 times higher power conversion efficiencies in devices with a SAM compared to those without the SAM. © 2011 American Chemical Society.

  10. Effects of Self-Assembled Monolayers on Solid-State CdS Quantum Dot Sensitized Solar Cells

    KAUST Repository

    Ardalan, Pendar

    2011-02-22

    Quantum dot sensitized solar cells (QDSSCs) are of interest for solar energy conversion because of their tunable band gap and promise of stable, low-cost performance. We have investigated the effects of self-assembled monolayers (SAMs) with phosphonic acid headgroups on the bonding and performance of cadmium sulfide (CdS) solid-state QDSSCs. CdS quantum dots ∼2 to ∼6 nm in diameter were grown on SAM-passivated planar or nanostructured TiO 2 surfaces by successive ionic layer adsorption and reaction (SILAR), and photovoltaic devices were fabricated with spiro-OMeTAD as the solid-state hole conductor. X-ray photoelectron spectroscopy, Auger electron spectroscopy, ultraviolet-visible spectroscopy, scanning electron microscopy, transmission electron microscopy, water contact angle measurements, ellipsometry, and electrical measurements were employed to characterize the materials and the resulting device performance. The data indicate that the nature of the SAM tailgroup does not significantly affect the uptake of CdS quantum dots on TiO2 nor their optical properties, but the presence of the SAM does have a significant effect on the photovoltaic device performance. Interestingly, we observe up to ∼3 times higher power conversion efficiencies in devices with a SAM compared to those without the SAM. © 2011 American Chemical Society.

  11. LIGNOCELLULOSE NANOCOMPOSITE CONTAINING COPPER SULFIDE

    Directory of Open Access Journals (Sweden)

    Sanchi Nenkova

    2011-04-01

    Full Text Available Copper sulfide-containing lignocellulose nanocomposites with improved electroconductivity were obtained. Two methods for preparing the copper sulfide lignocellulose nanocomposites were developed. An optimization of the parameters for obtaining of the nanocomposites with respect to obtaining improved electroconductivity, economy, and lower quantities and concentration of copper and sulfur ions in waste waters was conducted. The mechanisms and schemes of delaying and subsequent connection of copper sulfides in the lignocellulosic matrix were investigated. The modification with a system of 2 components: cupric sulfate pentahydrate (CuSO4. 5H2O and sodium thiosulfate pentahydrate (Na2S2O3.5H2O for wood fibers is preferred. Optimal parameters were established for the process: 40 % of the reduction system; hydromodule M=1:6; and ratio of cupric sulfate pentahydrate:sodium thiosulfate pentahydrate = 1:2. The coordinative connection of copper ions with oxygen atoms of cellulose OH groups and aromatic nucleus in lignin macromolecule was observed.

  12. Chemical dissolution of sulfide minerals

    Science.gov (United States)

    Chao, T.T.; Sanzolone, R.F.

    1977-01-01

    Chemical dissolution treatments involving the use of aqua regia, 4 N HNO3, H2O2-ascorbic acid, oxalic acid, KClO3+HCl, and KClO3+HCl followed by 4 N HNO3 were applied to specimens of nine common sulfide minerals (galena, chalcopyrite, cinnabar, molybdenite, orpiment, pyrite, stibnite, sphalerite, and tetrahedrite) mixed individually with a clay loam soil. The resultant decrease in the total sulfur content of the mixture, as determined by using the Leco induction furnace, was used to evaluate the effectiveness of each chemical treatment. A combination of KClO3+HCl followed by 4 N HNO3 boiling gently for 20 min has been shown to be very effective in dissolving all the sulfide minerals. This treatment is recommended to dissolve metals residing in sulfide minerals admixed with secondary weathering products, as one step in a fractionation scheme whereby metals in soluble and adsorbed forms, and those associated with organic materials and secondary oxides, are first removed by other chemical extractants.

  13. Cadmium in blood and hypertension

    International Nuclear Information System (INIS)

    Eum, Ki-Do; Lee, Mi-Sun; Paek, Domyung

    2008-01-01

    Objectives:: This study is to examine the effect of cadmium exposure on blood pressure in Korean general population. Methods:: The study population consisted of 958 men and 944 women who participated in the 2005 Korean National Health and Nutrition Examination Survey (KNHANES), in which blood pressure and blood cadmium were measured from each participant. Results:: The mean blood cadmium level was 1.67 μg/L (median level 1.55). The prevalence of hypertension was 26.2%. The blood cadmium level was significantly higher among those subjects with hypertension than those without (mean level 1.77 versus 1.64 μg/dL). After adjusting for covariates, the odds ratio of hypertension comparing the highest to the lowest tertile of cadmium in blood was 1.51 (95% confidence interval 1.13 to 2.05), and a dose-response relationship was observed. Systolic, diastolic, and mean arterial blood pressure were all positively associated with blood cadmium level, and this effect of cadmium on blood pressure was markedly stronger when the kidney function was reduced. Conclusions:: Cadmium exposures at the current level may have increased the blood pressure of Korean general population

  14. Cadmium in blood and hypertension

    Energy Technology Data Exchange (ETDEWEB)

    Eum, Ki-Do; Lee, Mi-Sun [Department of Environmental Health, Graduate School of Public Health and Institute of Health and Environment, Seoul National University, Seoul (Korea, Republic of); Paek, Domyung [Department of Environmental Health, Graduate School of Public Health and Institute of Health and Environment, Seoul National University, Seoul (Korea, Republic of)], E-mail: paekdm@snu.ac.kr

    2008-12-15

    Objectives:: This study is to examine the effect of cadmium exposure on blood pressure in Korean general population. Methods:: The study population consisted of 958 men and 944 women who participated in the 2005 Korean National Health and Nutrition Examination Survey (KNHANES), in which blood pressure and blood cadmium were measured from each participant. Results:: The mean blood cadmium level was 1.67 {mu}g/L (median level 1.55). The prevalence of hypertension was 26.2%. The blood cadmium level was significantly higher among those subjects with hypertension than those without (mean level 1.77 versus 1.64 {mu}g/dL). After adjusting for covariates, the odds ratio of hypertension comparing the highest to the lowest tertile of cadmium in blood was 1.51 (95% confidence interval 1.13 to 2.05), and a dose-response relationship was observed. Systolic, diastolic, and mean arterial blood pressure were all positively associated with blood cadmium level, and this effect of cadmium on blood pressure was markedly stronger when the kidney function was reduced. Conclusions:: Cadmium exposures at the current level may have increased the blood pressure of Korean general population.

  15. Sulfide intrusion and detoxification in seagrasses ecosystems

    DEFF Research Database (Denmark)

    Hasler-Sheetal, Harald; Holmer, Marianne

    Sulfide intrusion in seagrasses represents a global threat to seagrasses and thereby an important parameter in resilience of seagrass ecosystems. In contrast seegrasses colonize and grow in hostile sediments, where they are constantly exposed to invasion of toxic gaseous sulfide. Remarkably little...... strategies of seagrasses to sustain sulfide intrusion. Using stable isotope tracing, scanning electron microscopy with x-ray analysis, tracing sulfur compounds combined with ecosystem parameters we found different spatial, intraspecific and interspecific strategies to cope with sulfidic sediments. 1...... not present in terrestrial plants at that level. Sulfide is not necessarily toxic but used as sulfur nutrition, presupposing healthy seagrass ecosystems that can support detoxification mechanisms. Presence or absence of those mechanisms determines susceptibility of seagrass ecosystems to sediment sulfide...

  16. Neutron diffraction investigations of the superionic conductors lithium sulfide and sodium sulfide

    International Nuclear Information System (INIS)

    Altorfer, F.

    1990-03-01

    Statics and dynamics of the superionic conductors lithium sulfide and sodium sulfide were investigated using the following experimental methods: elastic scattering on sodium sulfide powder in the temperature range 20 - 1000 C, elastic scattering on a lithium sulfide single crystal in the temperature range 20 - 700 C, inelastic scattering on a 7 Li 2 S single crystal at 10 K. 34 figs., 2 tabs., 10 refs

  17. Cadmium contamination of agricultural soils and crops resulting from sphalerite weathering

    International Nuclear Information System (INIS)

    Robson, T.C.; Braungardt, C.B.; Rieuwerts, J.; Worsfold, P.

    2014-01-01

    The biogeochemistry and bioavailability of cadmium, released during sphalerite weathering in soils, were investigated under contrasting agricultural scenarios to assess health risks associated with sphalerite dust transport to productive soils from mining. Laboratory experiments (365 d) on temperate and sub-tropical soils amended with sphalerite ( −1 ). Wheat grown in spiked temperate soil accumulated ≈38% (29 μmol kg −1 ) of the liberated Cd, exceeding food safety limits. In contrast, rice grown in flooded sub-tropical soil accumulated far less Cd (0.60 μmol kg −1 ) due to neutral soil pH and Cd bioavailability was possibly also controlled by secondary sulfide formation. The results demonstrate long-term release of Cd to soil porewaters during sphalerite weathering. Under oxic conditions, Cd may be sufficiently bioavailable to contaminate crops destined for human consumption; however flooded rice production limits the impact of sphalerite contamination. -- Highlights: • Sphalerite containing cadmium presents a hazard when present in agricultural soils. • Sphalerite dissolution was slow (0.6–1.2% y −1 ) but constant in contrasting soils. • Cadmium was released during dissolution and was bioavailable to wheat and rice. • Wheat grains accumulated potentially harmful cadmium concentrations. • Flooded paddy (reducing) soils reduced cadmium bioavailability to rice. -- Sphalerite dissolves steadily in oxic agricultural soils and can release highly bioavailable Cd, which may contaminate food crops destined for human consumption

  18. Cadmium exposure in the Swedish environment

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    This report gives a thorough description of cadmium in the Swedish environment. It comprises three parts: Cadmium in Sweden - environmental risks;, Cadmium in goods - contribution to environmental exposure;, and Cadmium in fertilizers, soil, crops and foods - the Swedish situation. Separate abstracts have been prepared for all three parts

  19. Sulfidation behavior of Fe20Cr alloys

    International Nuclear Information System (INIS)

    Pillis, Marina Fuser

    2001-01-01

    Alloys for use in high temperature environments rely on the formation of an oxide layer for their protection. Normally, these protective oxides are Cr 2 O 3 , Al 2 O 3 and, some times, SiO 2 . Many industrial gaseous environments contain sulfur. Sulfides, formed in the presence of sulfur are thermodynamically less stable, have lower melting points and deviate much more stoichiometrically, compared to the corresponding oxides. The mechanism of sulfidation of various metals is as yet not clear, in spite of the concerted efforts during the last decade. To help address this situation, the sulfidation behavior of Fe20Cr has been studied as a function of compositional modifications and surface state of the alloy. The alloys Fe20Cr, Fe20Cr0.7Y, Fe20Cr5Al and Fe20Cr5Al0.6Y were prepared and three sets of sulfidation tests were carried out. In the first set, the alloys were sulfidized at 700 deg C and 800 deg C for 10h. In the second set, the alloys were pre-oxidized at 1000 deg C and then sulfidized at 800 deg C for up to 45h. In the third set of tests, the initial stages of sulfidation of the alloys was studied. All the tests were carried out in a thermobalance, in flowing H 2 /2%H 2 S, and the sulfidation behavior determined as mass change per unit area. Scanning electron microscopy coupled to energy dispersive spectroscopy and X-ray diffraction analysis were used to characterize the reaction products. The addition of Y and Al increased sulfidation resistance of Fe20Cr. The addition of Y altered the species that diffused predominantly during sulfide growth. It changed from predominant cationic diffusion to predominant anionic diffusion. The addition of Al caused an even greater increase in sulfidation resistance of Fe20Cr, with the parabolic rate constant decreasing by three orders of magnitude. Y addition to the FeCrAl alloy did not cause any appreciable alteration in sulfidation resistance. Pre-oxidation of the FeCrAl and FeCrAlY alloys resulted in an extended

  20. Cadmium and zinc

    International Nuclear Information System (INIS)

    Safaya, N.M.; McLean, J.E.; Halverson, G.A.

    1987-01-01

    Cadmium and zinc are naturally occurring trace metals that are often considered together because of their close geochemical association and similarities in chemical reactivity. The loss of two electrons from an atom of Cd or Zn imparts to each an electron configuration with completely filled d orbitals; this results in a highly stable 2/sup +/ oxidation state. But Cd and Zn differ greatly in their significance to biological systems. Whereas Zn is an essential nutrient for plants, animals, and humans, Cd is best known for its toxicity to plants and as a causative agent of several disease syndromes in animals and humans

  1. and Cadmium Zinc Telluride

    African Journals Online (AJOL)

    Bheema

    INTRODUCTION. Semiconductor nanoparticles or Quantum Dots (QDs), in particular II-VI materials, have ... the study of structural, electronic transport and optical properties of Zn doped CdTe thin films, ...... Bhattacharya, S.K & Anjali, K. 2007.

  2. Cadmium immobilization by hydroxyapatite

    Directory of Open Access Journals (Sweden)

    Smičiklas Ivana D.

    2003-01-01

    Full Text Available The contamination of air, soil and water by cadmium is a great environmental problem. If cadmium occurs in nature in ionic form, soluble in water, it easily enters into the food chain. Hydroxyapatite (HAP, Ca-o(POAe(OH2 is a sparingly soluble salt and an excellent matrix for the removal of heavy metals from solutions. Considerable research attention has been paid to the bond between Cc/2+ ions and synthetic hydroxyapatite of known composition. The sorption mechanism is complex. The dominant process is ion exchange, but surface adsorption, surface complexation and coprecipitation can also contribute to the overall mechanism. The sorption capacity depends on the characteristics of hydroxyapatite itself and on the experimental conditions. Under optimum conditions a maximum capacity of 0.8 mol Cd2+/mol HAP can be achieved. HAP is a potential sorbent for the remediation of contaminated water and soil, for industrial waste treatment, and it is also referenced as a material that can be used as a barrier around waste depositories.

  3. Cadmium colours: composition and properties

    International Nuclear Information System (INIS)

    Paulus, J.; Knuutinen, U.

    2004-01-01

    The composition and the properties of cadmium aquarelle colours are discussed. The examined colours were 24 different aquarelle cadmium colours from six different manufacturers. The colours ranged from light, bright yellows to dark, deep-red tones. The aim of this research was to find out if the pigments contain cadmium salts: sulphides and/or selenides. This information will help in choosing watercolours in conservation processes. Today, aquarelle colours not containing cadmium pigments are being sold as cadmium colours; thus their properties might be different from actual cadmium colours. The aim of the research was to verify that the colour samples contained cadmium pigments and to estimate their compositions and ageing properties. Element analyses were performed from colour samples using micro-chemical tests and X-ray fluorescence measurements. Thin-layer chromatography was used for analysing gum Arabic as a possible binding medium in the chosen colour samples. Through ageing tests, the resistance of the colour samples to the exposure to light, heat and humidity was studied. Visible-light spectroscopy was used in determining the hues and hue changes of the aquarelle colour samples. The spectrophotometer used the CIE L * a * b * tone colour measuring system. From the colour measurements the changes in the lightness/darkness, the redness, the yellowness and the saturation of the samples were examined. (orig.)

  4. Cadmium in the biofuel system

    International Nuclear Information System (INIS)

    Aabyhammar, T.; Fahlin, M.; Holmroos, S.

    1993-12-01

    Removal of biofuel depletes the soil of important nutrients. Investigations are being made of possibilities to return most of these nutrients by spreading the ashes remaining after combustion in the forest or on field. Return of ashes implies that both beneficial and harmful substances are returned. This study has been conducted to illustrate that the return of cadmium implies the greatest risk for negative influences. The occurrence, utilization, emissions and effects of cadmium are discussed. The behaviour of cadmium in soil is discussed in detail. Flows and quantities of cadmium in Swedish society are reviewed. Flows and quantities of both total and plant available cadmium in the entire forest and arable areas of Sweden are given. A scenario for a bioenergy system of max 100 TWh is discussed. The cadmium flow in different biofuels and forest raw products, and anticipated amounts of ashes and cadmium concentrations, are calculated. Power production from biofuels is surveyed. Possibilities to clean ashes have been examined in laboratory experiments. Ashes and trace elements occurring as a result of the gasification of biofuels are reviewed. Strategies for handling ashes are discussed. Proposals on continued inputs in both the biological and technical sciences are made. 146 refs, 23 figs, 38 tabs

  5. Label-free room-temperature phosphorescence turn-on detection of tiopronin based on Cu{sup 2+}-modulated homocysteine-capped manganese doped zinc sulfide quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Yan; Fan, Zhefeng, E-mail: crush_bc@163.com

    2015-04-15

    A label-free turn-on room-temperature phosphorescence (RTP) sensor for tiopronin based on Cu{sup 2+}-modulated homocysteine (Hcy)-capped Mn-doped ZnS quantum dots (QDs) was described in this paper. The RTP of Hcy-capped Mn-doped ZnS QDs can be effectively quenched by Cu{sup 2+} due to the binding of Cu{sup 2+} to the Hcy on the surface of the QDs and the electron transfer generated from the photoexcited QDs to Cu{sup 2+}. The high affinity of tiopronin to Cu{sup 2+} enables the dissociation of the ion from the surface of the QDs, thereby forming a stable complex with tiopronin in the solution, and recovering the RTP of the QDs. The Cu{sup 2+}-induced RTP quenching and subsequent tiopronin-induced RTP recovery for MPA-capped ZnS QDs provide a solid basis for the present RTP sensor based on QDs for the detection of tiopronin. The detection limit for tiopronin is 0.18 ng mL{sup −1}, the relative standard deviations is 1.9%, and the recovery of urine and serum samples with tiopronin addition range from 96% to 106% under optimal conditions. The proposed method was successfully applied to biological fluids and obtained satisfactory results. - Highlights: • The high water-solubility Mn-doped-QDs with good RTP property was synthesized. • The RTP intensity of the QDs could be effectively quenched by Cu{sup 2+} ions. • Cu{sup 2+} ions were selectively separated from the QDs by tiopronin. • The RTP of the Cu{sup 2+}-modulated QDs was restored by tiopronin. • The tiopronin sensor was applied to biological fluids with satisfactory results.

  6. Sulfide toxicity kinetics of a uasb reactor

    Directory of Open Access Journals (Sweden)

    D. R. Paula Jr.

    2009-12-01

    Full Text Available The effect of sulfide toxicity on kinetic parameters of anaerobic organic matter removal in a UASB (up-flow anaerobic sludge blanket reactor is presented. Two lab-scale UASB reactors (10.5 L were operated continuously during 12 months. The reactors were fed with synthetic wastes prepared daily using glucose, ammonium acetate, methanol and nutrient solution. One of the reactors also received increasing concentrations of sodium sulfide. For both reactors, the flow rate of 16 L.d-1 was held constant throughout the experiment, corresponding to a hydraulic retention time of 15.6 hours. The classic model for non-competitive sulfide inhibition was applied to the experimental data for determining the overall kinetic parameter of specific substrate utilization (q and the sulfide inhibition coefficient (Ki. The application of the kinetic parameters determined allows prediction of methanogenesis inhibition and thus the adoption of operating parameters to minimize sulfide toxicity in UASB reactors.

  7. Cadmium-containing waste and recycling possibilities

    International Nuclear Information System (INIS)

    Wiegand, V.; Rauhut, A.

    1981-01-01

    To begin with, the processes of cadmium production from zinc ores in smelting plants or from intermediates of other metal works are described. A considerable amount of the cadmium is obtained in the recycling process in zinc, lead, and copper works. The way of the cadmium-containing intermediaries, processing, enrichment, and disposal of cadmium waste are described. Uses of cadmium and its compounds are mentioned, and cadmium consumption in the years 1973-1977 in West Germany is presented in a table. Further chapters discuss the production and the way of waste during production and processing of cadmium-containing products, the problem of cadmium in household refuse and waste incineration plants, and the problem of cadmium emissions. (IHOE) [de

  8. Discovery of the cadmium isotopes

    International Nuclear Information System (INIS)

    Amos, S.; Thoennessen, M.

    2010-01-01

    Thirty-seven cadmium isotopes have been observed so far and the discovery of these isotopes is discussed here. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  9. Interactions between N-acetyl-L-cysteine protected CdTe quantum dots and doxorubicin through spectroscopic method

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiupei, E-mail: xiupeiyang@163.com [Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, Nanchong 637000 (China); College of Chemistry and Chemical Engineering, China West Normal University, Nanchong 637000 (China); Lin, Jia; Liao, Xiulin; Zong, Yingying; Gao, Huanhuan [College of Chemistry and Chemical Engineering, China West Normal University, Nanchong 637000 (China)

    2015-06-15

    Highlights: • CdTe quantum dots with the diameter of 3–5 nm were synthesized in aqueous solution. • The modified CdTe quantum dots showed well fluorescence properties. • The interaction between the CdTe quantum dots and doxorubicin (DR) was investigated. - Abstract: N-acetyl-L-cysteine protected cadmium telluride quantum dots with a diameter of 3–5 nm were synthesized in aqueous solution. The interaction between N-acetyl-L-cysteine/cadmium telluride quantum dots and doxorubicin was investigated by ultraviolet–visible absorption and fluorescence spectroscopy at physiological conditions (pH 7.2, 37 °C). The results indicate that electron transfer has occurred between N-acetyl-L-cysteine/cadmium telluride quantum dots and doxorubicin under light illumination. The quantum dots react readily with doxorubicin to form a N-acetyl-L-cysteine/cadmium telluride-quantum dots/doxorubicin complex via electrostatic attraction between the −NH{sub 3}{sup +} moiety of doxorubicin and the −COO{sup −} moiety of N-acetyl-L-cysteine/cadmium telluride quantum dots. The interaction of N-acetyl-L-cysteine/cadmium telluride-quantum dots/doxorubicin complex with bovine serum albumin was studied as well, showing that the complex might induce the conformation change of bovine serum due to changes in microenvironment of bovine serum.

  10. Interactions between N-acetyl-L-cysteine protected CdTe quantum dots and doxorubicin through spectroscopic method

    International Nuclear Information System (INIS)

    Yang, Xiupei; Lin, Jia; Liao, Xiulin; Zong, Yingying; Gao, Huanhuan

    2015-01-01

    Highlights: • CdTe quantum dots with the diameter of 3–5 nm were synthesized in aqueous solution. • The modified CdTe quantum dots showed well fluorescence properties. • The interaction between the CdTe quantum dots and doxorubicin (DR) was investigated. - Abstract: N-acetyl-L-cysteine protected cadmium telluride quantum dots with a diameter of 3–5 nm were synthesized in aqueous solution. The interaction between N-acetyl-L-cysteine/cadmium telluride quantum dots and doxorubicin was investigated by ultraviolet–visible absorption and fluorescence spectroscopy at physiological conditions (pH 7.2, 37 °C). The results indicate that electron transfer has occurred between N-acetyl-L-cysteine/cadmium telluride quantum dots and doxorubicin under light illumination. The quantum dots react readily with doxorubicin to form a N-acetyl-L-cysteine/cadmium telluride-quantum dots/doxorubicin complex via electrostatic attraction between the −NH 3 + moiety of doxorubicin and the −COO − moiety of N-acetyl-L-cysteine/cadmium telluride quantum dots. The interaction of N-acetyl-L-cysteine/cadmium telluride-quantum dots/doxorubicin complex with bovine serum albumin was studied as well, showing that the complex might induce the conformation change of bovine serum due to changes in microenvironment of bovine serum

  11. Biological indicators of cadmium exposure and toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Shaikh, Z A; Smith, L M

    1986-01-01

    The increasing environmental and occupational exposure of populations to cadmium creates the need for biological indicators of cadmium exposure and toxicity. The advantages and disadvantages of monitoring blood cadmium, urinary, fecal, hair, and tissue cadmium, serum creatine, beta 2-microglobulin, alpha 1-anti-trypsin and other proteins, and urinary amino acids, enzymes, total proteins, glucose, beta 2-microglobulin, retinol-binding protein, lysozyme, and metallothionein are discussed. It is concluded that urinary cadmium, metallothionein and beta 2-microglubulin may be used together to assess cadmium exposure and toxicity. 66 references.

  12. Phosphonate self-assembled monolayers as organic linkers in solid-state quantum dot sensetized solar cells

    KAUST Repository

    Ardalan, Pendar

    2010-06-01

    We have employed X-ray photoelectron spectroscopy (XPS), ultraviolet-visible (UV-vis) spectroscopy, infrared (IR) spectroscopy, water contact angle (WCA) measurements, ellipsometry, and electrical measurements to study the effects of self-assembled monolayers (SAMs) with phosphonic acid headgroups on the bonding and performance of cadmium sulfide (CdS) solid-state quantum dot sensitized solar cells (QDSSCs). ∼2 to ∼6 nm size CdS quantum dots (QDs) were grown on the SAM-passivated TiO2 surfaces by successive ionic layer adsorption and reaction (SILAR). Our results show differences in the bonding of the CdS QDs at the TiO2 surfaces with a SAM linker. Moreover, our data indicate that presence of a SAM increases the CdS uptake on TiO2 as well as the performance of the resulting devices. Importantly, we observe ∼2 times higher power conversion efficiencies in the devices with a SAM compared to those that lack a SAM. © 2010 IEEE.

  13. Quantum Dots Microstructured Optical Fiber for X-Ray Detection

    Science.gov (United States)

    DeHaven, Stan; Williams, Phillip; Burke, Eric

    2015-01-01

    Microstructured optical fibers containing quantum dots scintillation material comprised of zinc sulfide nanocrystals doped with magnesium sulfide are presented. These quantum dots are applied inside the microstructured optical fibers using capillary action. The x-ray photon counts of these fibers are compared to the output of a collimated CdTe solid state detector over an energy range from 10 to 40 keV. The results of the fiber light output and associated effects of an acrylate coating and the quantum dot application technique are discussed.

  14. Sulfidation/oxidation resistant alloys

    International Nuclear Information System (INIS)

    Smith, G.D.; Tassen, C.S.

    1989-01-01

    The patent describes a nickel-base, high chromium alloy. It is characterized by excellent resistance to sulfidation and oxidation at elevated temperatures as high as 2000 degrees F. (1093 degrees C.) and higher, a stress-rupture life of about 200 hours or more at a temperature at least as high as 1800 degrees F. (990:0083 degrees C.) and under a stress of 2000 psi, good tensile strength and good ductility both at room and elevated temperature. The alloy consists essentially of about 27 to 35% chromium, about 2.5 to 5% aluminum, about 2.5 to about 6% iron, 0.5 to 2.5% columbium, up to 0.1% carbon, up to 1% each of titanium and zirconium, up to 0.05% cerium, up to 0.05% yttrium, up to 1% silicon, up to 1% manganese, and the balance nickel

  15. Studies on voltammetric determination of cadmium in samples containing native and digested proteins

    Energy Technology Data Exchange (ETDEWEB)

    Drozd, Marcin; Pietrzak, Mariusz, E-mail: mariusz@ch.pw.edu.pl; Malinowska, Elżbieta

    2014-03-01

    Highlights: • Proteins exhibit diverse impact on the DPASV cadmium signals. • Proteins subjected to HNO{sub 3} introduce less interference, than the native ones. • Optimal amount of SDS depends on the kind of protein. • Presence of thiolated coating agents of QDs do not influence the analysis. - Abstract: This work focuses on determination of cadmium ions using anodic stripping voltammetry (ASV) on thin film mercury electrode in conditions corresponding to those obtained after digestion of cadmium-based quantum dots and their conjugates. It presents the impact of selected proteins, including potential receptors and surface blocking agents on the voltammetric determination of cadmium. Experiments regarding elimination of interferences related to proteins presence using sodium dodecyl sulfate (SDS) are also shown. Effect of SDS on selected analytical parameters and simplicity of analyses carried out was investigated in the framework of current studies. The significant differences of influence among tested proteins on ASV cadmium determination, as well as the variability in SDS effectiveness as the antifouling agent were observed and explained. This work is especially important for those, who design new bioassays and biosensors with a use of quantum dots as electrochemical labels, as it shows what problems may arise from presence of native and digested proteins in tested samples.

  16. Quantum optics

    National Research Council Canada - National Science Library

    Agarwal, G. S

    2013-01-01

    .... Focusing on applications of quantum optics, the textbook covers recent developments such as engineering of quantum states, quantum optics on a chip, nano-mechanical mirrors, quantum entanglement...

  17. Iron-sulfide crystals in probe deposits

    DEFF Research Database (Denmark)

    Laursen, Karin; Frandsen, Flemming

    1998-01-01

    Iron-sulfides were observed in deposits collected on a probe inserted at the top of the furnace of a coal-fired power station in Denmark. The chemical composition of the iron-sulfides is equivalent to pyrrhotite (FeS). The pyrrhotites are present as crystals and, based on the shape of the crystals......: (1) impact of low viscous droplets of iron sulfide; and (2) sulfur diffusion. Previous research on the influence of pyrite on slagging focused on the decomposition of pyrite into pyrrhotite and especially on the oxidation stage of this product during impact on the heat transfer surfaces...

  18. Microbial control of hydrogen sulfide production

    Energy Technology Data Exchange (ETDEWEB)

    Montgomery, A.D.; Bhupathiraju, V.K.; Wofford, N.; McInerney, M.J. [Univ. of Oklahoma, Tulsa, OK (United States)] [and others

    1995-12-31

    A sulfide-resistant strain of Thiobacillus denitrificans, strain F, prevented the accumulation of sulfide by Desulfovibrio desulfuricans when both organisms were grown in liquid medium. The wild-type strain of T. denitrificans did not prevent the accumulation of sulfide produced by D. desulfuricans. Strain F also prevented the accumulation of sulfide by a mixed population of sulfate-reducing bacteria enriched from an oil field brine. Fermentation balances showed that strain F stoichiometrically oxidized the sulfide produced by D. desulfuricans and the oil field brine enrichment to sulfate. The ability of a strain F to control sulfide production in an experimental system of cores and formation water from the Redfield, Iowa, natural gas storage facility was also investigated. A stable, sulfide-producing biofilm was established in two separate core systems, one of which was inoculated with strain F while the other core system (control) was treated in an identical manner, but was not inoculated with strain F. When formation water with 10 mM acetate and 5 mM nitrate was injected into both core systems, the effluent sulfide concentrations in the control core system ranged from 200 to 460 {mu}M. In the test core system inoculated with strain F, the effluent sulfide concentrations were lower, ranging from 70 to 110 {mu}M. In order to determine whether strain F could control sulfide production under optimal conditions for sulfate-reducing bacteria, the electron donor was changed to lactate and inorganic nutrients (nitrogen and phosphate sources) were added to the formation water. When nutrient-supplemented formation water with 3.1 mM lactate and 10 mM nitrate was used, the effluent sulfide concentrations of the control core system initially increased to about 3,800 {mu}M, and then decreased to about 1,100 {mu}M after 5 weeks. However, in the test core system inoculated with strain F, the effluent sulfide concentrations were much lower, 160 to 330 {mu}M.

  19. Sulfide Intrusion and Detoxification in the Seagrass Zostera marina

    DEFF Research Database (Denmark)

    Hasler-Sheetal, Harald; Holmer, Marianne

    2015-01-01

    Gaseous sulfide intrusion into seagrasses growing in sulfidic sediments causes little or no harm to the plant, indicating the presence of an unknown sulfide tolerance or detoxification mechanism. We assessed such mechanism in the seagrass Zostera marina in the laboratory and in the field...... as sulfate throughout the plant. We conclude that avoidance of sulfide exposure by reoxidation of sulfide in the rhizosphere or aerenchyma and tolerance of sulfide intrusion by incorporation of sulfur in the plant are likely major survival strategies of seagrasses in sulfidic sediments....

  20. Synthesis and structural studies of copper sulfide nanocrystals

    Directory of Open Access Journals (Sweden)

    Peter A. Ajibade

    Full Text Available We report the synthesis and structural studies of copper sulfide nanocrystals from copper(II dithiocarbamate single molecule precursors. The optical studies of the as-prepared copper sulfide nanoparticles were carried out using UV–Visible and photoluminescence spectroscopy. The absorption spectra show absorption band edges at 287 nm and exhibit considerable blue shift that could be ascribed to the quantum confinement effects as a result of the small crystallite sizes of the nanoparticles and the photoluminescence spectra show emission curves that are red shifted with respect to the absorption band edges. The structural studies were carried out using powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. The XRD patterns revealed the formation of hexagonal structure of covellite CuS with estimated crystallite sizes of 17.3–18.6 nm. The TEM images showed particles with almost spherical or rod shapes with average crystallite sizes of 3–9.8 nm. SEM images showed morphology with ball-like microsphere on the surfaces and EDS spectra confirmed the presence of CuS nanoparticles. Keywords: CuS, Dithiocarbamate, Nanoparticles, Electron microscopy, AFM

  1. Uptake and distribution of cadmium in corn

    International Nuclear Information System (INIS)

    Peel, J.W.; Vetter, R.J.; Christian, J.E.; Kessler, W.V.; McFee, W.W.

    1978-01-01

    The uptake and distribution of cadmium in corn (Zea mays) treated at various time intervals after planting and sampled at various times after treatment were measured. Cadmium was found to accumulate in all parts sampled. As shown in field studies, stems and leaves generally concentrated more cadmium than did husks, cobs, kernels, silks, or tassels. Samples of stems and leaves from corn treated 23 days after planting and sampled 5 days later exhibited higher concentrations of cadmium than samples taken 25, 45, 65, or 85 days after treatment. Concentrations generally decreased with time. Greenhouse studies showed that corn exposed to cadmium for the longest period of time accumulated the greatest total cadmium. The highest cadmium concentrations were found in the base or lowest leaves sampled 45 days after planting; this suggests a useful technique for quick screening corn crops for cadmium pollution

  2. Zinc-induced protection against cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Early, J.L.; Schnell, R.C.

    1978-02-01

    Pretreatment of male rats with cadmium acetate potentiates the duration of hexobarbital hypnosis and inhibits the rate of hepatic microsomal drug metabolism. Pretreatment of rats with zinc acetate protects against these alterations in drug action elicited by cadmium.

  3. Magnetic properties and phase transformations of iron sulfides synthesized under the hydrothermal method

    Science.gov (United States)

    Li, S. H.; Chen, Y. H.

    2016-12-01

    The iron sulfide nano-minerals possess advantages of high abundance, low cost, and low toxicity. These advantages make them be competitive in the magnetic, electronic, and photoelectric applications. Mackinawite can be used in soil or water remediations. Greigite is very important for paleomagnetic and geochemical environment studies and the anode materials for lithium ion batteries. Besides, greigite is also utilized for hyperthermia and biomedicine. Pyrrhotite can be applied as geothermometry. Due to the above-mentioned reasons, iron sulfide minerals have specific significances and they must be further investigated, like their phase transformations, magnetic properties, and etc. In this study, the iron sulfide minerals were synthesized by using a hydrothermal method. The ex-situ and in-situ X-ray diffraction (XRD) was used to examine the crystal structure and phase transformation of iron sulfide minerals. The Transmission electron microscopy (TEM) and superconducting quantum interference device (SQUID) were carried out to investigate their morphology and magnetic properties, respectively. The results suggested that the phase transformation sequence was followed the order: mackinawite → greigite → (smythite) → pyrrhotite. Two pure mineral phases of greigite and pyrrhotite were obtained under the hydrothermal conditions. The morphology of the pure greigite is granular aggregates with a particle size of approximately 30 nm and pyrrhotite presented a hexagonal sheet stacking with a particle size of thousands nanometers. The greigite had a ferri-magnetic behavior and pyrrhotite was weak ferro-magnetic. Both of them had a pseudo-single magnetic domain (PSD) based on the Day's plot from SQUID data. The complete phase-transformation pathways and high magnetization of iron sulfide minerals are observed in this study and these kind of iron sulfide minerals are worthy to further study.

  4. Cadmium uptake by plants

    Energy Technology Data Exchange (ETDEWEB)

    Haghiri, F.

    1973-01-01

    Absorption of /sup 115m/Cd by soybean (Gylcine max l.) plants via foliar and root systems and translocation into the seed was determined. The uptake of /sup 115m/Cd by soybeans via the root system was more efficient than that of the foliar placement. Growth and Cd concentrations of soybean and wheat (Triticum aestivum l.) tops were influenced by soil-applied Cd. In both crops, the Cd concentration of plant tops increased while yield decreased with increasing levels of applied Cd. Cadmium toxicitiy began to occur in both crops at the lowest level of soil applied Cd (2.5 ppM). With soybean plants, Cd toxicity symptoms resembled fe chlorosis. For wheat plants there were no visual symptoms other than the studied growth. The relative concentration of Cd found in several vegetable crops varied depending on the plant species. The relative Cd concentration in descending order for various vegetables was lettuce (Lactuca sativa l.) > radish top (Raphanus sativus l.) > celery stalk (Apium graveolens l.) > celery leaves greater than or equal to green pepper (Capsicum frutescens l.) > radish roots.

  5. Crossett Hydrogen Sulfide Air Sampling Report

    Science.gov (United States)

    This report summarizes the results of the EPA’s hydrogen sulfide air monitoring conducted along Georgia Pacific’s wastewater treatment system and in surrounding Crossett, AR, neighborhoods in 2017.

  6. Bioavailability of cadmium from linseed and cocoa

    DEFF Research Database (Denmark)

    Hansen, Max; Sloth, Jens Jørgen; Rasmussen, Rie Romme

    In Denmark and EU the exposure of cadmium from food is at a level that is relatively close to the Tolerable Daily Intake (TDI). This report describes an investigation of the bioavailability of cadmium in selected food items known to contain high levels of cadmium. The purpose was to provide data...

  7. Air-water transfer of hydrogen sulfide

    DEFF Research Database (Denmark)

    Yongsiri, C.; Vollertsen, J.; Rasmussen, M. R.

    2004-01-01

    The emissions process of hydrogen sulfide was studied to quantify air–water transfer of hydrogen sulfide in sewer networks. Hydrogen sulfide transfer across the air–water interface was investigated at different turbulence levels (expressed in terms of the Froude number) and pH using batch...... experiments. By means of the overall mass–transfer coefficient (KLa), the transfer coefficient of hydrogen sulfide (KLaH2S), referring to total sulfide, was correlated to that of oxygen (KLaO2) (i.e., the reaeration coefficient). Results demonstrate that both turbulence and pH in the water phase play...... a significant role for KLaH2S. An exponential expression is a suitable representation for the relationship between KLaH2S and the Froude number at all pH values studied (4.5 to 8.0). Because of the dissociation of hydrogen sulfide, KLaH2S increased with decreasing pH at a constant turbulence level. Relative...

  8. Coprecipitation of cadmium with calcite

    International Nuclear Information System (INIS)

    Fujino, Osamu; Kumagai, Tetsu; Shigematsu, Tsunenobu; Matsui, Masakazu

    1976-01-01

    The distribution of cadmium between precipitates of calcite and saturated aqueous solution was measured at 25 0 C to understand the distribution of cadmium in the bivalves. Calcite was precipitated from calcium bicarbonate solution by the gradual release of carbon dioxide. The cadmium ions were coprecipitated in calcite, obeying the logarithmic distribution law. The apparent distribution coefficient was decreased as α, α'-dipyridyl increased, but the true distribution coefficient was found to be an almost constant value, 560. This value is fairly close to the ratio of solubility product constants K sub(calcite)/K sub(CdCO 3 ), 890. This suggests that the deviation of the present solid solution from ideality is not very large. (auth.)

  9. Health hazards of environmental cadmium pollution

    Energy Technology Data Exchange (ETDEWEB)

    Nordberg, G F

    1974-01-01

    Cadmium, a metal widely used in industrial processes, has been recognized to be a highly toxic and dangerous environmental pollutant. In this study the author describes the sources and occurrence of cadmium, and the intake by human beings. He states that present standards for daily intake do not allow sufficient safety margins. The fate and known effects of cadmium in human beings are summarized; some effects associated with cadmium are renal (kidney) damage, anemia, hypertension, and liver damage. Cadmium was identified as the main cause of the Itai-Itai disease in Japan, and epidemiological studies from various areas of Japan are presented. 64 references, 9 figures, 5 tables.

  10. Hydrogen sulfide can inhibit and enhance oxygenic photosynthesis in a cyanobacterium from sulfidic springs

    NARCIS (Netherlands)

    Klatt, Judith M.; Haas, Sebastian; Yilmaz, Pelin; de Beer, Dirk; Polerecky, Lubos

    We used microsensors to investigate the combinatory effect of hydrogen sulfide (H2S) and light on oxygenic photosynthesis in biofilms formed by a cyanobacterium from sulfidic springs. We found that photosynthesis was both positively and negatively affected by H2S: (i) H2S accelerated the recovery of

  11. Sulfide response analysis for sulfide control using a pS electrode in sulfate reducing bioreactors

    NARCIS (Netherlands)

    Villa Gomez, D.K.; Cassidy, J.; Keesman, K.J.; Sampaio, R.M.; Lens, P.N.L.

    2014-01-01

    Step changes in the organic loading rate (OLR) through variations in the influent chemical oxygen demand (CODin) concentration or in the hydraulic retention time (HRT) at constant COD/SO4 2- ratio (0.67) were applied to create sulfide responses for the design of a sulfide control in sulfate reducing

  12. Quantum Erasure: Quantum Interference Revisited

    OpenAIRE

    Walborn, Stephen P.; Cunha, Marcelo O. Terra; Pádua, Sebastião; Monken, Carlos H.

    2005-01-01

    Recent experiments in quantum optics have shed light on the foundations of quantum physics. Quantum erasers - modified quantum interference experiments - show that quantum entanglement is responsible for the complementarity principle.

  13. Transient Kinetic Analysis of Hydrogen Sulfide Oxidation Catalyzed by Human Sulfide Quinone Oxidoreductase*

    Science.gov (United States)

    Mishanina, Tatiana V.; Yadav, Pramod K.; Ballou, David P.; Banerjee, Ruma

    2015-01-01

    The first step in the mitochondrial sulfide oxidation pathway is catalyzed by sulfide quinone oxidoreductase (SQR), which belongs to the family of flavoprotein disulfide oxidoreductases. During the catalytic cycle, the flavin cofactor is intermittently reduced by sulfide and oxidized by ubiquinone, linking H2S oxidation to the electron transfer chain and to energy metabolism. Human SQR can use multiple thiophilic acceptors, including sulfide, sulfite, and glutathione, to form as products, hydrodisulfide, thiosulfate, and glutathione persulfide, respectively. In this study, we have used transient kinetics to examine the mechanism of the flavin reductive half-reaction and have determined the redox potential of the bound flavin to be −123 ± 7 mV. We observe formation of an unusually intense charge-transfer (CT) complex when the enzyme is exposed to sulfide and unexpectedly, when it is exposed to sulfite. In the canonical reaction, sulfide serves as the sulfur donor and sulfite serves as the acceptor, forming thiosulfate. We show that thiosulfate is also formed when sulfide is added to the sulfite-induced CT intermediate, representing a new mechanism for thiosulfate formation. The CT complex is formed at a kinetically competent rate by reaction with sulfide but not with sulfite. Our study indicates that sulfide addition to the active site disulfide is preferred under normal turnover conditions. However, under pathological conditions when sulfite concentrations are high, sulfite could compete with sulfide for addition to the active site disulfide, leading to attenuation of SQR activity and to an alternate route for thiosulfate formation. PMID:26318450

  14. Transient Kinetic Analysis of Hydrogen Sulfide Oxidation Catalyzed by Human Sulfide Quinone Oxidoreductase.

    Science.gov (United States)

    Mishanina, Tatiana V; Yadav, Pramod K; Ballou, David P; Banerjee, Ruma

    2015-10-09

    The first step in the mitochondrial sulfide oxidation pathway is catalyzed by sulfide quinone oxidoreductase (SQR), which belongs to the family of flavoprotein disulfide oxidoreductases. During the catalytic cycle, the flavin cofactor is intermittently reduced by sulfide and oxidized by ubiquinone, linking H2S oxidation to the electron transfer chain and to energy metabolism. Human SQR can use multiple thiophilic acceptors, including sulfide, sulfite, and glutathione, to form as products, hydrodisulfide, thiosulfate, and glutathione persulfide, respectively. In this study, we have used transient kinetics to examine the mechanism of the flavin reductive half-reaction and have determined the redox potential of the bound flavin to be -123 ± 7 mV. We observe formation of an unusually intense charge-transfer (CT) complex when the enzyme is exposed to sulfide and unexpectedly, when it is exposed to sulfite. In the canonical reaction, sulfide serves as the sulfur donor and sulfite serves as the acceptor, forming thiosulfate. We show that thiosulfate is also formed when sulfide is added to the sulfite-induced CT intermediate, representing a new mechanism for thiosulfate formation. The CT complex is formed at a kinetically competent rate by reaction with sulfide but not with sulfite. Our study indicates that sulfide addition to the active site disulfide is preferred under normal turnover conditions. However, under pathological conditions when sulfite concentrations are high, sulfite could compete with sulfide for addition to the active site disulfide, leading to attenuation of SQR activity and to an alternate route for thiosulfate formation. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. Experimental simulations of sulfide formation in the solar nebula.

    Science.gov (United States)

    Lauretta, D S; Lodders, K; Fegley, B

    1997-07-18

    Sulfurization of meteoritic metal in H2S-H2 gas produced three different sulfides: monosulfide solid solution [(Fe,Ni)1-xS], pentlandite [(Fe,Ni)9-xS8], and a phosphorus-rich sulfide. The composition of the remnant metal was unchanged. These results are contrary to theoretical predictions that sulfide formation in the solar nebula produced troilite (FeS) and enriched the remaining metal in nickel. The experimental sulfides are chemically and morphologically similar to sulfide grains in the matrix of the Alais (class CI) carbonaceous chondrite, suggesting that these meteoritic sulfides may be condensates from the solar nebula.

  16. Uptake, retention and internalization of quantum dots in Daphnia is influenced by particle surface functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Feswick, A., E-mail: afeswick@yahoo.ca [Center for Environmental and Human Toxicology, University of Florida, PO Box 110885, Gainesville, FL 32611 (United States); Canadian Rivers Institute, University of New Brunswick, PO Box 5050, Saint John NB, CA (United States); Griffitt, R.J., E-mail: joe.griffitt@usm.edu [Department of Coastal Sciences, University of Southern Mississippi, 703 East Beach Drive, Ocean Springs, MS 39564 (United States); Siebein, K., E-mail: kerry.siebein@nist.gov [Major Analytical Instrumentation Center, University of Florida, PO Box 116400, Gainesville, FL 32611 (United States); Barber, D.S., E-mail: barberd@vetmed.ufl.edu [Center for Environmental and Human Toxicology, University of Florida, PO Box 110885, Gainesville, FL 32611 (United States)

    2013-04-15

    Highlights: ► Daphnia underwent a waterborne exposure of PEG, NH{sub 2} and COOH functionalized quantum dot nanoparticles. ► There was preferential retention of COOH nanoparticles. ► TEM demonstrated that NH{sub 2} and COOH nanoparticles were internalized in cells adjacent to the GI tract. ► This cellular internalization was confirmed using energy dispersive spectroscopy. -- Abstract: Nanomaterials are a diverse group of compounds whose inevitable release into the environment warrants study of the fundamental processes that govern the ingestion, uptake and accumulation in aquatic organisms. Nanomaterials have the ability to transfer to higher trophic levels in aquatic ecosystems, and recent evidence suggests that the surface chemistry of both the nanoparticle and biological membrane can influence uptake kinetics. Therefore, our study investigates the effect of surface functionalization on uptake, internalization and depuration in Daphnia spp. Uncharged (polyethylene glycol; PEG), positively charged (amino-terminated: NH{sub 2}) and negatively charged (carboxyl-modified; COOH) cadmium selenide/zinc sulfide quantum dots were used to monitor ingestion, uptake and depuration of nanometals in Daphnia magna and Ceriodaphnia dubia over 24 h of exposure. These studies demonstrated that particles with higher negative charge (COOH quantum dots) were taken up to a greater extent by Daphnia (259.17 ± 17.70 RFU/20 Daphnia) than either the NH{sub 2} (150.01 ± 18.91) or PEG quantum dots (95.17 ± 9.78), however this is likely related to the functional groups attached to the nanoparticles as there were no real differences in zeta potential. Whole body fluorescence associates well with fluorescent microscopic images obtained at the 24 h timepoint. Confocal and electron microscopic analysis clearly demonstrated that all three types of quantum dots could cross the intestinal epithelial barrier and be translocated to other cells. Upon cessation of exposure, elimination of

  17. [Investigation of urinary cadmium reference of general population in two rural high background areas of soil cadmium and non-cadmium-polluted in China].

    Science.gov (United States)

    Han, Jingxiu; Li, Qiujuan; Yao, Dancheng; Zheng, Jiangang; Zhang, Wenli; Shang, Qi

    2014-09-01

    To study the reference of urinary. cadmium of the general population in rural high background areas of soil cadmium and non-cadmium contaminated in China. In rural high background areas of soil cadmium and non-cadmium contaminated, randomly selected non-occupational-cadmium exposed population 1134 people (male 519, female 615) with each gender and age groups, questionnaire surveyed and collected random urine. Urinary cadmium and urinary creatinine (Cr) concentration were tested, excluding urinary Cr 3 g/L. Analyze the impact factors of urinary cadmium and calculated 95% quantile (P,95 ) of urinary cadmium after correction by urinary Cr. Female median urinary cadmium was significantly higher than men, male smokers median urinary cadmium was significantly higher than male non-smokers (P 30 year-old. According to gender, and 15 -30, 30 years old, analysis the upper limit of cadmium in urine. The 95% upper limit of urinary cadmium of 30 year-old female (12.24 microg/gCr) was significantly higher than other populations ( population exceeded the upper limit (5 microg/gCr) of the occupational cadmium poisoning diagnostic criteria in China (GBZ 17-2002). In the two rural high background areas of soil cadmium and non-cadmium polluted , urinary cadmium reference of non-cadmium-occupational-exposed male is <9.0 microg/gCr, and female <13.0 microg/gCr.

  18. Sulfide Precipitation in Wastewater at Short Timescales

    DEFF Research Database (Denmark)

    Kiilerich, Bruno; van de Ven, Wilbert; Nielsen, Asbjørn Haaning

    2017-01-01

    Abatement of sulfides in sewer systems using iron salts is a widely used strategy. When dosing at the end of a pumping main, the reaction kinetics of sulfide precipitation becomes important. Traditionally the reaction has been assumed to be rapid or even instantaneous. This work shows that this i......Abatement of sulfides in sewer systems using iron salts is a widely used strategy. When dosing at the end of a pumping main, the reaction kinetics of sulfide precipitation becomes important. Traditionally the reaction has been assumed to be rapid or even instantaneous. This work shows...... that this is not the case for sulfide precipitation by ferric iron. Instead, the reaction time was found to be on a timescale where it must be considered when performing end-of-pipe treatment. For real wastewaters at pH 7, a stoichiometric ratio around 14 mol Fe(II) (mol S(−II))−1 was obtained after 1.5 s, while the ratio...

  19. Mechanisms of cadmium induced genomic instability

    Energy Technology Data Exchange (ETDEWEB)

    Filipic, Metka, E-mail: metka.filipic@nib.si [National Institute of Biology, Department for Genetic Toxicology and Cancer Biology, Ljubljana (Slovenia)

    2012-05-01

    Cadmium is an ubiquitous environmental contaminant that represents hazard to humans and wildlife. It is found in the air, soil and water and, due to its extremely long half-life, accumulates in plants and animals. The main source of cadmium exposure for non-smoking human population is food. Cadmium is primarily toxic to the kidney, but has been also classified as carcinogenic to humans by several regulatory agencies. Current evidence suggests that exposure to cadmium induces genomic instability through complex and multifactorial mechanisms. Cadmium dose not induce direct DNA damage, however it induces increase in reactive oxygen species (ROS) formation, which in turn induce DNA damage and can also interfere with cell signalling. More important seems to be cadmium interaction with DNA repair mechanisms, cell cycle checkpoints and apoptosis as well as with epigenetic mechanisms of gene expression control. Cadmium mediated inhibition of DNA repair mechanisms and apoptosis leads to accumulation of cells with unrepaired DNA damage, which in turn increases the mutation rate and thus genomic instability. This increases the probability of developing not only cancer but also other diseases associated with genomic instability. In the in vitro experiments cadmium induced effects leading to genomic instability have been observed at low concentrations that were comparable to those observed in target organs and tissues of humans that were non-occupationally exposed to cadmium. Therefore, further studies aiming to clarify the relevance of these observations for human health risks due to cadmium exposure are needed.

  20. Mechanisms of cadmium induced genomic instability

    International Nuclear Information System (INIS)

    Filipič, Metka

    2012-01-01

    Cadmium is an ubiquitous environmental contaminant that represents hazard to humans and wildlife. It is found in the air, soil and water and, due to its extremely long half-life, accumulates in plants and animals. The main source of cadmium exposure for non-smoking human population is food. Cadmium is primarily toxic to the kidney, but has been also classified as carcinogenic to humans by several regulatory agencies. Current evidence suggests that exposure to cadmium induces genomic instability through complex and multifactorial mechanisms. Cadmium dose not induce direct DNA damage, however it induces increase in reactive oxygen species (ROS) formation, which in turn induce DNA damage and can also interfere with cell signalling. More important seems to be cadmium interaction with DNA repair mechanisms, cell cycle checkpoints and apoptosis as well as with epigenetic mechanisms of gene expression control. Cadmium mediated inhibition of DNA repair mechanisms and apoptosis leads to accumulation of cells with unrepaired DNA damage, which in turn increases the mutation rate and thus genomic instability. This increases the probability of developing not only cancer but also other diseases associated with genomic instability. In the in vitro experiments cadmium induced effects leading to genomic instability have been observed at low concentrations that were comparable to those observed in target organs and tissues of humans that were non-occupationally exposed to cadmium. Therefore, further studies aiming to clarify the relevance of these observations for human health risks due to cadmium exposure are needed.

  1. Functional consortium for denitrifying sulfide removal process.

    Science.gov (United States)

    Chen, Chuan; Ren, Nanqi; Wang, Aijie; Liu, Lihong; Lee, Duu-Jong

    2010-03-01

    Denitrifying sulfide removal (DSR) process simultaneously converts sulfide, nitrate, and chemical oxygen demand from industrial wastewaters to elemental sulfur, nitrogen gas, and carbon dioxide, respectively. This investigation utilizes a dilution-to-extinction approach at 10(-2) to 10(-6) dilutions to elucidate the correlation between the composition of the microbial community and the DSR performance. In the original suspension and in 10(-2) dilution, the strains Stenotrophomonas sp., Thauera sp., and Azoarcus sp. are the heterotrophic denitrifiers and the strains Paracoccus sp. and Pseudomonas sp. are the sulfide-oxidizing denitrifers. The 10(-4) dilution is identified as the functional consortium for the present DSR system, which comprises two functional strains, Stenotrophomonas sp. strain Paracoccus sp. At 10(-6) dilution, all DSR performance was lost. The functions of the constituent cells in the DSR granules were discussed based on data obtained using the dilution-to-extinction approach.

  2. Production and Preservation of Sulfide Layering in Mercury's Magma Ocean

    Science.gov (United States)

    Boukare, C.-E.; Parman, S. W.; Parmentier, E. M.; Anzures, B. A.

    2018-05-01

    Mercury's magma ocean (MMO) would have been sulfur-rich. At some point during MMO solidification, it likely became sulfide saturated. Here we present physiochemical models exploring sulfide layer formation and stability.

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

    International Nuclear Information System (INIS)

    Hossain, Sk Tofajjen; Mukherjee, Samir Kumar

    2013-01-01

    Highlights: • Toxic effect of CdS NPs on the growth and cell division in E. coli was studied. • CdS NPs affected cell surface topology and cell division. • Downregulation of both FtsZ and FtsQ was observed due to NPs exposure. • CdS NPs affected HeLa cell morphology with fragmented nuclei. • All such effects might be due to elevated oxidative stress. -- Abstract: 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 IC 50 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

  4. Biomolecule-assisted construction of cadmium sulfide hollow spheres with structure-dependent photocatalytic activity.

    Science.gov (United States)

    Wei, Chengzhen; Zang, Wenzhe; Yin, Jingzhou; Lu, Qingyi; Chen, Qun; Liu, Rongmei; Gao, Feng

    2013-02-25

    In this study, we report the synthesis of monodispersive solid and hollow CdS spheres with structure-dependent photocatalytic abilities for dye photodegradation. The monodispersive CdS nanospheres were constructed with the assistance of the soulcarboxymthyi chitosan biopolymer under hydrothermal conditions. The solid CdS spheres were corroded by ammonia to form hollow CdS nanospheres through a dissolution-reprecipitation mechanism. Their visible-light photocatalytic activities were investigated, and the results show that both the solid and the hollow CdS spheres have visible-light photocatalytic abilities for the photodegradation of dyes. The photocatalytic properties of the CdS spheres were demonstrated to be structure dependent. Although the nanoparticles comprising the hollow spheres have larger sizes than those comprising the solid spheres, the hollow CdS spheres have better photocatalytic performances than the solid CdS spheres, which can be attributed to the special hollow structure. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Highly Efficient Photocatalytic Hydrogen Production of Flower-like Cadmium Sulfide Decorated by Histidine

    Science.gov (United States)

    Wang, Qizhao; Lian, Juhong; Li, Jiajia; Wang, Rongfang; Huang, Haohao; Su, Bitao; Lei, Ziqiang

    2015-09-01

    Morphology-controlled synthesis of CdS can significantly enhance the efficiency of its photocatalytic hydrogen production. In this study, a novel three-dimensional (3D) flower-like CdS is synthesized via a facile template-free hydrothermal process using Cd(NO3)2•4H2O and thiourea as precursors and L-Histidine as a chelating agent. The morphology, crystal phase, and photoelectrochemical performance of the flower-like CdS and pure CdS nanocrystals are carefully investigated via various characterizations. Superior photocatalytic activity relative to that of pure CdS is observed on the flower-like CdS photocatalyst under visible light irradiation, which is nearly 13 times of pure CdS. On the basis of the results from SEM studies and our analysis, a growth mechanism of flower-like CdS is proposed by capturing the shape evolution. The imidazole ring of L-Histidine captures the Cd ions from the solution, and prevents the growth of the CdS nanoparticles. Furthermore, the photocatalytic contrast experiments illustrate that the as-synthesized flower-like CdS with L-Histidine is more stable than CdS without L-Histidine in the hydrogen generation.

  6. Shape-Dependent Photocatalytic Activity of Hydrothermally Synthesized Cadmium Sulfide Nanostructures.

    Science.gov (United States)

    Kundu, Joyjit; Khilari, Santimoy; Pradhan, Debabrata

    2017-03-22

    The effective surface area of the nanostructured materials is known to play a prime role in catalysis. Here we demonstrate that the shape of the nanostructured materials plays an equally important role in their catalytic activity. Hierarchical CdS microstructures with different morphologies such as microspheres assembled of nanoplates, nanorods, nanoparticles, and nanobelts are synthesized using a simple hydrothermal method by tuning the volume ratio of solvents, i.e., water or ethylenediamine (en). With an optimum solvent ratio of 3:1 water:en, the roles of other synthesis parameters such as precursor's ratio, temperature, and precursor combinations are also explored and reported here. Four selected CdS microstructures are used as photocatalysts for the degradation of methylene blue and photoelectrochemical water splitting for hydrogen generation. In spite of smaller effective surface area of CdS nanoneedles/nanorods than that of CdS nanowires network, the former exhibits higher catalytic activity under visible light irradiation which is ascribed to the reduced charge recombination as confirmed from the photoluminescence study.

  7. Highly Efficient Photocatalytic Hydrogen Production of Flower-like Cadmium Sulfide Decorated by Histidine

    OpenAIRE

    Wang, Qizhao; Lian, Juhong; Li, Jiajia; Wang, Rongfang; Huang, Haohao; Su, Bitao; Lei, Ziqiang

    2015-01-01

    Morphology-controlled synthesis of CdS can significantly enhance the efficiency of its photocatalytic hydrogen production. In this study, a novel three-dimensional (3D) flower-like CdS is synthesized via a facile template-free hydrothermal process using Cd(NO3)2•4H2O and thiourea as precursors and L-Histidine as a chelating agent. The morphology, crystal phase, and photoelectrochemical performance of the flower-like CdS and pure CdS nanocrystals are carefully investigated via various characte...

  8. A comprehensive study on the photocatalytic activity of coupled copper oxide-cadmium sulfide nanoparticles

    Science.gov (United States)

    Senobari, Samaneh; Nezamzadeh-Ejhieh, Alireza

    2018-05-01

    Coupled CdS-CuO nanoparticles (NPs) subjected in the photocatalytic degradation of Methylene blue (MB) aqueous solution. The calcination temperature and the crystallite phase of CuO had a significant role on the photocatalytic activity of the coupled system and CuO200/2h-CdS catalyst (containing CuO calcined at 200 °C for 2 h) showed the best photocatalytic activity. The coupled system showed increased activity with respect to the monocomponent semiconductors. The prepared catalysts characterized by x-ray diffraction (XRD), scanning electron microscope equipped with energy dispersive X-ray (EDX) analyzer, x-ray mapping, Fourier transform infrared (FTIR) spectroscopy, diffuse reflectance spectroscopy (DRS) and electrochemical impedance spectroscopy (EIS) techniques. The best degradation extent of MB was obtained at: CMB: 1 mg L-1, pH 5, 80 min irradiation time and 0.8 g L-1 of the CuO200/2h-CdS catalyst. The chemical oxygen demand (COD) confirmed about 83% of MB molecules can be mineralized at the optimum conditions.

  9. Growth analysis of cadmium sulfide thin films by atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Moutinho, H.R.; Dhere, R.G.; Ramanathan, K. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    1996-05-01

    CdS films have been deposited by solution growth on SnO{sub 2} and glass substrates. Nucleation on SnO{sub 2} occurs at early deposition times, and complete conformal coverage is observed at low thickness values. The average grain size of the CdS films is established at these early times. In films deposited on glass substrates, nucleation is slower and occurs through 3-dimensional islands that increase in size and number as deposition proceeds. Optical measurements show that the bandgap values of CdS films deposited on SnO{sub 2} depend mainly on substrate structure. Hydrogen heat treatment does not affect the surface morphology of the samples, but decreases bandgap values.

  10. Determination of the band alignment of multi-walled carbon nanotubes decorated with cadmium sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Silva, M.F.O., E-mail: mangos@ufmg.br [Departamento de Física, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte (Brazil); Paniago, R.M., E-mail: paniago@fisica.ufmg.br [Departamento de Física, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte (Brazil); Miquita, D.R., E-mail: douglas.miquita@gmail.com [Centro de Microscopia da Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte (Brazil); Pinheiro, C.B., E-mail: basilio@fisica.ufmg.br [Departamento de Física, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte (Brazil); Ladeira, L.O., E-mail: ladeira@fisica.ufmg.br [Departamento de Física, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte (Brazil); Ferlauto, A.S., E-mail: ferlauto@fisica.ufmg.br [Departamento de Física, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte (Brazil); Rodrigues, W.N., E-mail: wagner@fisica.ufmg.br [Departamento de Física, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte (Brazil); Centro de Microscopia da Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte (Brazil)

    2014-12-01

    Highlights: • MWCNTs and CdS composite were grown by the solvothermal method. • Photoelectron spectroscopy was used to analyze energy levels at the interface. • The interface shows zero value for the Schottky barrier between MWCNTs and CdS. • MWCNTs act as ohmic contacts for CdS nanoparticles. • MWCNTs may act as charge collector in CdS-based devices.

  11. Superluminescence of cadmium sulfide crystals under pulse X-ray radiation

    International Nuclear Information System (INIS)

    Pavlovskaya, N.G.; Tarasov, M.D.; Balakin, V.A.; Varava, V.P.; Lobov, S.I.; Surskij, O.K.; Tsukerman, V.A.

    1977-01-01

    Studies were made to elucidate luminescence properties of CdS crystal radiated by short pulses of braking x-ray radiation. Such a radiation causes the appearance of superluminescence. The radiation was carried out at 295 and 170 K, the radiation dose being changed from 3600 to 1600 r/pulse. At the temperature of 295 K light luminescence was registered at the wave length of 528 nm and half-width of 15 nm. While the temperature lowers, the radiation shifts to the range of shorter wave lengths, and a decrease of the spectrum half-width is observed. With the increase of radiation dose the decrease of radiation spectrum half-width is observed. Approximate calculations show that to achieve the spectrum narrowing to 1 nm at room temperature it is necessary to increase radiation dose per pulse 5-6 times

  12. Acute inhalation toxicity of carbonyl sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Benson, J.M.; Hahn, F.F.; Barr, E.B. [and others

    1995-12-01

    Carbonyl sulfide (COS), a colorless gas, is a side product of industrial procedures sure as coal hydrogenation and gasification. It is structurally related to and is a metabolite of carbon disulfide. COS is metabolized in the body by carbonic anhydrase to hydrogen sulfide (H{sub 2}S), which is thought to be responsible for COS toxicity. No threshold limit value for COS has been established. Results of these studies indicate COS (with an LC{sub 50} of 590 ppm) is slightly less acutely toxic than H{sub 2}S (LC{sub 50} of 440 ppm).

  13. Girdler-sulfide process physical properties

    International Nuclear Information System (INIS)

    Neuburg, H.J.; Atherley, J.F.; Walker, L.G.

    1977-05-01

    Physical properties of pure hydrogen sulfide and of gaseous and liquid solutions of the H 2 S-H 2 O system have been formulated. Tables for forty-nine different properties in the pressure and temperature range of interest to the Girdler-Sulfide (GS) process for heavy water production are given. All properties are presented in SI units. A computer program capable of calculating properties of the pure components as well as gaseous mixtures and liquid solutions at saturated and non-saturated conditions is included. (author)

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

    International Nuclear Information System (INIS)

    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 2 . Induction of CdBS was observed in strains that differed widely in their sensitivity of CdCl 2 . This report describes the induction of CdBS and some of its characteristics. 17 refs., 4 figs., 1 tab

  15. Cadmium and Cadmium/Zinc Ratios and Tobacco-Related Morbidities

    Science.gov (United States)

    Richter, Patricia; Faroon, Obaid; Pappas, R. Steven

    2017-01-01

    Metals are one of five major categories of carcinogenic or toxic constituents in tobacco and tobacco smoke. Cadmium is highly volatile and a higher percentage of the total tobacco cadmium content is efficiently transferred to mainstream tobacco smoke than many other toxic metals in tobacco. Inhaled cadmium bioaccumulates in the lungs and is distributed beyond the lungs to other tissues, with a total body biological half-life of one to two decades. Chronic cadmium exposure through tobacco use elevates blood and urine cadmium concentrations. Cadmium is a carcinogen, and an inducer of proinflammatory immune responses. Elevated exposure to cadmium is associated with reduced pulmonary function, obstructive lung disease, bronchogenic carcinoma, cardiovascular diseases including myocardial infarction, peripheral arterial disease, prostate cancer, cervical cancer, pancreatic cancer, and various oral pathologies. Cadmium and zinc have a toxicologically inverse relationship. Zinc is an essential element and is reportedly antagonistic to some manifestations of cadmium toxicity. This review summarizes associations between blood, urine, and tissue cadmium concentrations with emphasis on cadmium exposure due to tobacco use and several disease states. Available data about zinc and cadmium/zinc ratios and tobacco-related diseases is summarized from studies reporting smoking status. Collectively, data suggest that blood, urine, and tissue cadmium and cadmium/zinc ratios are often significantly different between smokers and nonsmokers and they are also different in smokers for several diseases and cancers. Additional biomonitoring data such as blood or serum and urine zinc and cadmium levels and cadmium/zinc ratios in smokers may provide further insight into the development and progression of diseases of the lung, cardiovascular system, and possibly other organs. PMID:28961214

  16. Cadmium and Cadmium/Zinc Ratios and Tobacco-Related Morbidities.

    Science.gov (United States)

    Richter, Patricia; Faroon, Obaid; Pappas, R Steven

    2017-09-29

    Metals are one of five major categories of carcinogenic or toxic constituents in tobacco and tobacco smoke. Cadmium is highly volatile and a higher percentage of the total tobacco cadmium content is efficiently transferred to mainstream tobacco smoke than many other toxic metals in tobacco. Inhaled cadmium bioaccumulates in the lungs and is distributed beyond the lungs to other tissues, with a total body biological half-life of one to two decades. Chronic cadmium exposure through tobacco use elevates blood and urine cadmium concentrations. Cadmium is a carcinogen, and an inducer of proinflammatory immune responses. Elevated exposure to cadmium is associated with reduced pulmonary function, obstructive lung disease, bronchogenic carcinoma, cardiovascular diseases including myocardial infarction, peripheral arterial disease, prostate cancer, cervical cancer, pancreatic cancer, and various oral pathologies. Cadmium and zinc have a toxicologically inverse relationship. Zinc is an essential element and is reportedly antagonistic to some manifestations of cadmium toxicity. This review summarizes associations between blood, urine, and tissue cadmium concentrations with emphasis on cadmium exposure due to tobacco use and several disease states. Available data about zinc and cadmium/zinc ratios and tobacco-related diseases is summarized from studies reporting smoking status. Collectively, data suggest that blood, urine, and tissue cadmium and cadmium/zinc ratios are often significantly different between smokers and nonsmokers and they are also different in smokers for several diseases and cancers. Additional biomonitoring data such as blood or serum and urine zinc and cadmium levels and cadmium/zinc ratios in smokers may provide further insight into the development and progression of diseases of the lung, cardiovascular system, and possibly other organs.

  17. Use of biogenic sulfide for ZnS precipitation

    NARCIS (Netherlands)

    Esposito, G.; Veeken, A.; Weijma, J.; Lens, P.N.L.

    2006-01-01

    A 600 ml continuously stirred tank reactor was used to assess the performance of a zinc sulfide precipitation process using a biogenic sulfide solution (the effluent of a sulfate-reducing bioreactor) as sulfide source. In all experiments, a proportional-integral (PI) control algorithm was used to

  18. Quantum optics

    National Research Council Canada - National Science Library

    Agarwal, G. S

    2013-01-01

    ..., quantum metrology, spin squeezing, control of decoherence and many other key topics. Readers are guided through the principles of quantum optics and their uses in a wide variety of areas including quantum information science and quantum mechanics...

  19. Modeling Sulfides, pH and Hydrogen Sulfide Gas in the Sewers of San Francisco

    DEFF Research Database (Denmark)

    Vollertsen, Jes; Revilla, Nohemy; Hvitved-Jacobsen, Thorkild

    2015-01-01

    An extensive measuring campaign targeted on sewer odor problems was undertaken in San Francisco. It was assessed whether a conceptual sewer process model could reproduce the measured concentrations of total sulfide in the wastewater and H2S gas in the sewer atmosphere, and to which degree...... such simulations have potential for further improving odor and sulfide management. The campaign covered measurement of wastewater sulfide by grab sampling and diurnal sampling, and H2S gas in the sewer atmosphere was logged. The tested model was based on the Wastewater Aerobic/Anaerobic Transformations in Sewers...... (WATS) sewer process concept, which never had been calibrated to such an extensive dataset. The study showed that the model was capable of reproducing the general levels of wastewater sulfide, wastewater pH, and sewer H2S gas. It could also reproduce the general variability of these parameters, albeit...

  20. Distribution of cadmium between calcium carbonate and solution, 2

    International Nuclear Information System (INIS)

    Kitano, Yasushi; Kanamori, Nobuko; Fujiyoshi, Ryoko

    1978-01-01

    The distribution coefficient of cadmium between calcite and solution has been measured in the calcium bicarbonate solution containing cadmium and chloride ions, which forms complexes with cadmium ions. It has been confirmed experimentally that cadmium carbonate is present as a solid solution between calcitic calcium carbonate and cadmium carbonate in the carbonate precipitate formed in the solution system. However, the constant value of the thermodynamic distribution coefficient of cadmium between calcite and solution has not been obtained experimentally in the calcium bicarbonate solution containing cadmium and chloride ions. It may have been caused by the very specific behavior of cadmium ions, but the exact reason remains unsolved and must be studied. (Kobatake, H.)

  1. Historical perspectives on cadmium toxicology

    International Nuclear Information System (INIS)

    Nordberg, Gunnar F.

    2009-01-01

    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.

  2. Lead and cadmium in food

    International Nuclear Information System (INIS)

    Gliesmann, S.; Kruse, H.; Kriews, M.; Mangels, H.

    1992-08-01

    The amounts of lead and cadmium produced and processed in these days are considerable. As a result, our environment is increasingly polluted by heavy metals and industrial installations, motor vehicles or incinerating plants appear to be among the main culprits here. Air and water are the media permitting the entry of heavy metals into our natural environment where they accumulate in the soil and then gradually migrate into the plants. Their further transport in the food constitutes the third step in the environmental spread of heavy metals. The consumption of muscle and organ meats, of vegetables, fruits, canned food and drinking water is unavoidably associated with some ingestion of lead and cadmium. The degree to which they are taken up and stored in different tissues is determined by absorption properties and the nutritional state of the organism. Cadmium tends to accumulate in the kidneys, lead is mainly stored in the bones. A continuously increasing uptake finally results in health injuries that range from unspecific complaints to damaged kidneys or bones and disorders of liver function. Children and elderly people are at a particular risk here. The level of food contamination is such that screening for heavy metals must be rigorously carried out once appropriate legal thresholds have been set, which ought to be based on proven detrimental effects of lead and cadmium on our health and also take account of infants and children or any other risk groups, where particular caution must be exercised. It should be pointed out that such thresholds have so far not been determined. (orig./MG) [de

  3. UV Laser Co-Photolytic Approach to Gas-Phase Formation and Deposition of Nano-Sized Germanium Sulfides.

    Czech Academy of Sciences Publication Activity Database

    Tomovska, R.; Vorlíček, Vladimír; Boháček, Jaroslav; Šubrt, Jan; Pola, Josef

    2006-01-01

    Roč. 182, 1 (2006) , s. 107-111 ISSN 0022-3573 R&D Projects: GA MŠk(CZ) ME 486 Institutional research plan: CEZ:AV0Z40720504; CEZ:AV0Z10100523; CEZ:AV0Z40320502 Keywords : laser deposition * germanium sulfides * nanomaterials Subject RIV: CH - Nuclear ; Quantum Chemistry Impact factor: 1.533, year: 2006

  4. Reaction between Hydrogen Sulfide and Limestone Calcines

    Czech Academy of Sciences Publication Activity Database

    Hartman, Miloslav; Svoboda, Karel; Trnka, Otakar; Čermák, Jiří

    2002-01-01

    Roč. 41, č. 10 (2002), s. 2392-2398 ISSN 0888-5885 R&D Projects: GA AV ČR IAA4072711; GA AV ČR IAA4072801 Keywords : hydrogen sulfide * limestone calcines * desulfurization Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.247, year: 2002

  5. Microaeration reduces hydrogen sulfide in biogas

    Science.gov (United States)

    Although there are a variety of biological and chemical treatments for removal of hydrogen sulfide (H2S) from biogas, all require some level of chemical or water inputs and maintenance. In practice, managing biogas H2S remains a significant challenge for agricultural digesters where labor and opera...

  6. Support Effect in Hydrodesulfurization over Ruthenium Sulfide

    Czech Academy of Sciences Publication Activity Database

    Gulková, Daniela; Kaluža, Luděk; Vít, Zdeněk; Zdražil, Miroslav

    2009-01-01

    Roč. 51, č. 2 (2009), s. 146-149 ISSN 1337-7027 R&D Projects: GA ČR GA104/06/0705 Institutional research plan: CEZ:AV0Z40720504 Keywords : ruthenium sulfide * hydrodesulfurization * support effect Subject RIV: CC - Organic Chemistry

  7. Monitoring sulfide and sulfate-reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, R.S.

    1995-12-31

    Simple yet precise and accurate methods for monitoring sulfate-reducing bacteria (SRB) and sulfide remain useful for the study of bacterial souring and corrosion. Test kits are available to measure sulfide in field samples. A more precise methylene blue sulfide assay for both field and laboratory studies is described here. Improved media, compared to that in API RP-38, for enumeration of SRB have been formulated. One of these, API-RST, contained cysteine (1.1 mM) as a reducing agent, which may be a confounding source of sulfide. While cysteine was required for rapid enumeration of SRB from environmental samples, the concentration of cysteine in medium could be reduced to 0.4 mM. It was also determined that elevated levels of yeast extract (>1 g/liter) could interfere with enumeration of SRB from environmental samples. The API-RST medium was modified to a RST-11 medium. Other changes in medium composition, in addition to reduction of cysteine, included reduction of the concentration of phosphate from 3.4 mM to 2.2 mM, reduction of the concentration of ferrous iron from 0.8 mM to 0.5 mM and preparation of a stock mineral solution to ease medium preparation. SRB from environmental samples could be enumerated in a week in this medium.

  8. Acid volatile sulfide (AVS)- a comment

    NARCIS (Netherlands)

    Meysman, F.J.R.; Middelburg, J.J.

    2005-01-01

    The review by Rickard and Morse (this volume) adequately summarizes our current understanding with respect to acid-volatile sulfides (AVS). At the same time, this review addresses some of the misunderstandings with regard to measurements and dynamics of this important sedimentary sulfur pool. In

  9. Carbon a support for sulfide catalysts

    NARCIS (Netherlands)

    Vissers, J.P.R.; Lensing, T.J.; Mercx, F.P.M.; Beer, de V.H.J.; Prins, R.

    1983-01-01

    Two types of carbon materials, carbon black composite and carbon covered alumina, were studied for-their use as support for sulfide catalysts. The following parameters were varied: type of carbon black, carbon coverage of the alumina and carbon pretreatment. Pore size distributions were determined

  10. Concurrent reduction and distillation: an improved technique for the recovery and chemical refinement of the isotopes of cadmium and zinc

    International Nuclear Information System (INIS)

    Caudill, H.H.; McBride, L.E.; McDaniel, E.W.

    1982-01-01

    The Electromagnetic Isotope Separations Program of the Oak Ridge National Laboratory has been involved in the separation, chemical recovery, and refinement of the stable isotopes of cadmium and zinc since 1946. Traditionally, the chemical refinement procedures for these elements consisted of ion exchange separations using anion exchange resins followed by pH-controlled hydrogen sulfide precipitations. The procedures were quite time-consuming and made it difficult to remove trace quantities of sulfur which interferes in subsequent attempts to prepare rolled metal foils. As demands for 113 Cd and 68 Zn (a precursor for the production of the radiopharmaceutical 67 Ga) increased, it became evident that a quicker, more efficient refinement procedure was needed. Details of an improved method, which employs concurrent hydrogen reduction and distillation in the recovery and refinement of isotopically enriched zinc, are described. Modifications of the procedure suitable for the refinement of cadmium isotopes are also described. 3 figures, 1 table

  11. Biomolecule-assisted hydrothermal synthesis of silver bismuth sulfide with nanostructures

    International Nuclear Information System (INIS)

    Kaowphong, Sulawan

    2012-01-01

    Silver bismuth sulfide (AgBiS 2 ) nanostructures were successfully prepared via a simple biomolecule-assisted hydrothermal synthesis at 200 °C for 12–72 h. Silver nitrate, bismuth nitrate and L-cysteine were used as starting materials. Here, the biomolecule, L-cysteine, was served as the sulfide source and a complexing agent. The products, characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), were cubic AgBiS 2 nanoparticles with a diameter range of about 20–75 nm. It was found that their crystallinity and particle size increased with increasing reaction time. The energy dispersive X-ray spectroscopy (EDX) and inductively coupled plasma optical emission spectrophotometry (ICP-OES) analyses were used to confirm the stoichiometry of AgBiS 2 . The optical band gap of the AgBiS 2 nanoparticles, calculated from UV–vis spectra, was 3.0 eV which indicated a strong blue shift because of the quantum confinement effect. A possible formation mechanism of the AgBiS 2 nanoparticles was also discussed. - Graphical abstract: The optical band gap of the as-prepared AgBiS 2 nanoparticles displays a strong blue shift comparing to the 2.46 eV of bulk AgBiS 2 caused by the quantum confinement effects. Highlights: ► A simple biomolecule-assisted hydrothermal method is developed to prepare AgBiS 2 . ► L-Cysteine is served as the sulfide source and a complexing agent. ► Increase in band gap of the AgBiS 2 nanoparticles attributes to the quantum confinement effects.

  12. Quantum Instantons and Quantum Chaos

    OpenAIRE

    Jirari, H.; Kröger, H.; Luo, X. Q.; Moriarty, K. J. M.; Rubin, S. G.

    1999-01-01

    Based on a closed form expression for the path integral of quantum transition amplitudes, we suggest rigorous definitions of both, quantum instantons and quantum chaos. As an example we compute the quantum instanton of the double well potential.

  13. Quantum metrology

    International Nuclear Information System (INIS)

    Xiang Guo-Yong; Guo Guang-Can

    2013-01-01

    The statistical error is ineluctable in any measurement. Quantum techniques, especially with the development of quantum information, can help us squeeze the statistical error and enhance the precision of measurement. In a quantum system, there are some quantum parameters, such as the quantum state, quantum operator, and quantum dimension, which have no classical counterparts. So quantum metrology deals with not only the traditional parameters, but also the quantum parameters. Quantum metrology includes two important parts: measuring the physical parameters with a precision beating the classical physics limit and measuring the quantum parameters precisely. In this review, we will introduce how quantum characters (e.g., squeezed state and quantum entanglement) yield a higher precision, what the research areas are scientists most interesting in, and what the development status of quantum metrology and its perspectives are. (topical review - quantum information)

  14. Study on the sulfidation behavior of smithsonite

    International Nuclear Information System (INIS)

    Wu, Dandan; Wen, Shuming; Deng, Jiushuai; Liu, Jian; Mao, Yingbo

    2015-01-01

    Highlights: • Zeta potential showed that the pH IEP of smithsonite decreased from 7.7 to 6. • ICP test showed the gradual reduction of C S in the solution. • SEM showed that the mineral surface was partially changed to ZnS film. • XPS indicated that the presence of a characteristic signal peak of sulfur ions. - Abstract: Zinc extraction from low-grade mineral resources of oxidized zinc has recently become a focus of study. Sulfidation is an important process in oxidized ore flotation. In this study, the influence of sulfur ion adsorption on smithsonite surface was investigated with the use of zeta potential, inductively coupled plasma (ICP), scanning electron microscope (SEM), and X-ray photoelectron spectroscopic studies. Zeta potential measurements of sodium sulfide showed that sulfur ions were adsorbed onto the surface of pure smithsonite, as evidenced by the increased negative charge and the decrease in the pH IEP of smithsonite from 7.7 to 6 after sodium sulfide treatment. The ICP test revealed the gradual reduction in sulfur ion adsorption onto the surface of smithsonite in pulp sulfur. After 30 min of absorption, C S in the solution declined from 1000 × 10 −6 mol/L to 1.4 × 10 −6 mol/L. SEM results showed that the mineral surface was partially changed to ZnS film after sodium sulfide treatment, whereas EDS analysis results showed that 2% S is contained on the smithsonite surface. X-ray photoelectron spectroscopy results indicated the presence of a characteristic signal peak of sulfur ions after sulfidation. Sulfur concentration increased to 11.89%, whereas oxygen concentration decreased from 42.31% to 13.74%. Sulfur ions were not only present during chemical adsorption, but were also incorporated into the crystal lattices of minerals by the exchange reaction between S 2− and CO 3 2− ions

  15. Cadmium accumulation by Axonopus compressus (Sw.) P. Beauv and Cyperus rotundas Linn growing in cadmium solution and cadmium-zinc contaminated soil

    OpenAIRE

    Paitip Thiravetyan; Vibol Sao; Woranan Nakbanpote

    2007-01-01

    This research investigated the phyto-remediation potentials of Cyperus rotundas Linn (Nutgrass) and Axonopus compressus (Sw.) P. Beauv (Carpetgrass) for cadmium removal from cadmium solution andcadmium-zinc contaminated soil. Plants growth in the solution showed that cadmium decreased the relative growth rate of both grasses. However, the amount of cadmium accumulated in shoot and root was increasedwith the increase in cadmium concentration and exposure time. Growth in fertile soil mixed with...

  16. Quantum Distinction: Quantum Distinctiones!

    OpenAIRE

    Zeps, Dainis

    2009-01-01

    10 pages; How many distinctions, in Latin, quantum distinctiones. We suggest approach of anthropic principle based on anthropic reference system which should be applied equally both in theoretical physics and in mathematics. We come to principle that within reference system of life subject of mathematics (that of thinking) should be equated with subject of physics (that of nature). For this reason we enter notions of series of distinctions, quantum distinction, and argue that quantum distinct...

  17. Improvement of cadmium phytoremediation after soil inoculation with a cadmium-resistant Micrococcus sp.

    Science.gov (United States)

    Sangthong, Chirawee; Setkit, Kunchaya; Prapagdee, Benjaphorn

    2016-01-01

    Cadmium-resistant Micrococcus sp. TISTR2221, a plant growth-promoting bacterium, has stimulatory effects on the root lengths of Zea mays L. seedlings under toxic cadmium conditions compared to uninoculated seedlings. The performance of Micrococcus sp. TISTR2221 on promoting growth and cadmium accumulation in Z. mays L. was investigated in a pot experiment. The results indicated that Micrococcus sp. TISTR2221significantly promoted the root length, shoot length, and dry biomass of Z. mays L. transplanted in both uncontaminated and cadmium-contaminated soils. Micrococcus sp. TISTR2221 significantly increased cadmium accumulation in the roots and shoots of Z. mays L. compared to uninoculated plants. At the beginning of the planting period, cadmium accumulated mainly in the shoots. With a prolonged duration of cultivation, cadmium content increased in the roots. As expected, little cadmium was found in maize grains. Soil cadmium was significantly reduced with time, and the highest percentage of cadmium removal was found in the bacterial-inoculated Z. mays L. after transplantation for 6 weeks. We conclude that Micrococcus sp. TISTR2221 is a potent bioaugmenting agent, facilitating cadmium phytoextraction in Z. mays L.

  18. [Investigation of urinary cadmium characteristics of the general population in three non-cadmium-polluted rural areas in China].

    Science.gov (United States)

    Han, Jingxiu; Hu, Ji; Sun, Hong; Jing, Qiqing; Wang, Xiaofeng; Lou, Xiaoming; Ding, Zhen; Chen, Xiaodong; Zhang, Wenli; Shang, Qi

    2014-11-01

    To investigate the characteristics of urinary cadmium of the non-occupational-cadmium-exposed population in non-cadmium contaminated rural area in China. Randomly selected non-occupational cadmium exposed population 2548 people (male 1290, female 1258) with each gender and age groups, questionnaire surveyed and collected random urine. Urinary cadmium and urinary creatinine (Cr) concentration were tested, excluding urinary Cr 3 g/L. Analyze the impact factors of urinary cadmium and calculated 95% quantile (P95) of urinary cadmium after correction by urinary Cr. Urinary cadmium increased with age and showed an upward trend. The urinary cadmium of the population of ≥ 30 years old was significantly higher than that of populations (China (GB Z17-2002). The urinary cadmium reference value of non-occupational-cadmium-exposed populations is China, but for smoking women over 30 year-old it needs more research to explore.

  19. Cadmium stress in wheat seedlings: growth, cadmium accumulation and photosynthesis

    DEFF Research Database (Denmark)

    Ci, Dunwei; Jiang, Dong; Wollenweber, Bernd

    2010-01-01

    parameters were generally depressed by Cd stress, especially under the high Cd concentrations. Cd concentration and accumulation in both shoots and roots increased with increasing external Cd concentrations. Relationships between corrected parameters of growth, photosynthesis and fluorescence and corrected......Seedlings of wheat (Triticum aestivum L.) cultivars Jing 411, Jinmai 30 and Yangmai 10 were exposed to 0, 10, 20, 30, 40 or 50 μM of CdCl2 in a solution culture experiment. The effects of cadmium (Cd) stress on wheat growth, leaf photon energy conversion, gas exchange, and Cd accumulation in wheat...

  20. Cadmium in the bioenergy system - a synthesis

    International Nuclear Information System (INIS)

    Ahlfont, K.

    1997-12-01

    Cadmium is a toxic metal without any known positive biological effects. Both emissions and atmospheric deposition of cadmium have decreased radically in Sweden during recent years. In Sweden, about 150 tonnes of cadmium was supplied to the technosphere in 1990, mostly originating from NiCd batteries. More than 100 tonnes of cadmium accumulated in the technosphere. Mankind takes up cadmium from water, food and particulate atmospheric pollution. Even small amounts may be injurious in the long-term since the half-life in the kidneys is 30 years. Cadmium in biofuel and ashes are generally a cause of discussion. Ashes from biofuel constitute a nutrient resource that should be returned to the soil. A possible risk with spreading ashes is the spreading of heavy metals, and then foremost cadmium, which is among the heavy metals that forest soils are considered to tolerate the least. Several studies on cadmium in the bioenergy system have been made, both within the Research Programme for Recycling of Wood-ash, and within Vattenfall's Bioenergy Project. The present report is intended to provide a picture of the current state of knowledge and to review plans for the future With a 3 page summary in English. 51 refs, 1 fig, 3 tabs

  1. 29 CFR 1926.1127 - Cadmium.

    Science.gov (United States)

    2010-07-01

    ... occupational exposure to cadmium as follows: (1) Reassess the employee's work practices and personal hygiene... employee's work practices and personal hygiene; the employee's respirator use, if any; the employee's...; assuring that all employees exposed to air cadmium levels above the PEL wear appropriate personal...

  2. Cadmium and children: Exposure and health effects.

    NARCIS (Netherlands)

    Schoeters, G.; Hond, E. Den; Zuurbier, M.; Naginiene, R.; Hazel, P.J. van den; Stilianakis, N.; Ronchetti, R.; Koppe, J.G.

    2006-01-01

    Cadmium exposure and accumulation in the body start at young age. Exposure routes in children are mainly via food, environmental tobacco smoke and house dust. Excretion from the body is limited. Cadmium accumulation in the kidney is responsible for effects such as nephrotoxicity and osteoporosis

  3. Immunochromatographic assay of cadmium levels in oysters.

    Science.gov (United States)

    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. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Association of urinary cadmium and myocardial infarction

    International Nuclear Information System (INIS)

    Everett, Charles J.; Frithsen, Ivar L.

    2008-01-01

    We conducted a cross-sectional analysis of individuals 45-79 years old in the National Health and Nutrition Examination Survey III (1988-1994) (NHANES III). Myocardial infarction was determined by electrocardiogram (ECG). Our sample included 4912 participants, which when weighted represented 52,234,055 Americans. We performed adjusted logistic regressions with the Framingham risk score, pack-years of smoking, race-ethnicity, and family history of heart attack, and diabetes as covariates. Urinary cadmium ≥0.88 μg/g creatinine had an odds ratio of 1.86 (95% CI 1.26-2.75) compared to urinary cadmium <0.43 μg/g creatinine. This result supports the hypothesis that cadmium is associated with coronary heart disease. When logistic regressions were done by gender, women, but not men, showed a significant association of urinary cadmium with myocardial infarction. Women with urinary cadmium ≥0.88 μg/g creatinine had an odds ratio of 1.80 (95% CI 1.06-3.04) compared to urinary cadmium <0.43 μg/g creatinine. When the analysis was restricted to never smokers (N=2187) urinary cadmium ≥0.88 μg/g creatinine had an odds ratio of 1.85 (95% CI 1.10-3.14) compared to urinary cadmium <0.43 μg/g creatinine

  5. Oral cadmium chloride intoxication in mice

    DEFF Research Database (Denmark)

    Andersen, O; Nielsen, J B; Svendsen, P

    1988-01-01

    Diethyldithiocarbamate (DDC) is known to alleviate acute toxicity due to injection of cadmium salts. However, when cadmium chloride was administered by the oral route, DDC enhanced rather than alleviated the acute toxicity; both oral and intraperitoneal (i.p.) administration of DDC had this effect...

  6. Electro-spark machining of cadmium antimonide

    International Nuclear Information System (INIS)

    Ivanovskij, V.N.; Stepakhina, K.A.

    1975-01-01

    Experimental data on electrical erosion of the semiconductor material (cadmium antimonide) alloyed with tellurium are given. The potentialisies and expediency of using the electric-spark method of cutting cadmium antimonide ingots with the resistivity of 1 ohm is discussed. Cutting has been carried out in distilled water and in the air

  7. Cadmium toxcity in the pregnant rat

    International Nuclear Information System (INIS)

    Martin, P.G.; Hitchcock, B.B.; King, J.F.

    1978-01-01

    Iron-deficient and normal pregnant rats were assigned to groups that either received a dose of cadmium (0.025, 0.050, or 0.100 mmole) plus 8 μCi of /sup 115m/Cd on day 18 of gestation or served as a nondosed group. Animals were either sacrificed 3 days after the dosing or allowed to litter (nondosed and 0.100 mmole cadmium groups only); pups and dams were sacrificed at 14 days of age. Viability of iron-deficient dams and fetuses and pups from iron-deficient dams was affected by the 0.100 mmole cadmium dose to a greater degree than was that in comparable normal animals. Although calculated amounts of cadmium deposited in the dam's liver, kidney, blood, tibia, and fetuses were greater in iron-deficient than in normal animals at all doses, differences were not significant except in the amount of cadmium accumulated in the placenta at the highest cadmium doses. Total deposition in the placentas/litter was similar for normal and iron-deficient groups at each dose level. The decreased viability may have been due to the dam's decreased food intake; blockage of nutrients, especially minerals, by cadmium--protein complexes in the placenta; or hormonal interruptions of pregnancy by steroid--cadmium complexes

  8. Novel Cadmium Resistance Determinant in Listeria monocytogenes.

    Science.gov (United States)

    Parsons, Cameron; Lee, Sangmi; Jayeola, Victor; Kathariou, Sophia

    2017-03-01

    Listeria monocytogenes is a foodborne pathogen that can cause severe disease (listeriosis) in susceptible individuals. It is ubiquitous in the environment and often exhibits resistance to heavy metals. One of the determinants that enables Listeria to tolerate exposure to cadmium is the cadAC efflux system, with CadA being a P-type ATPase. Three different cadA genes (designated cadA1 to cadA3 ) were previously characterized in L. monocytogenes A novel putative cadmium resistance gene ( cadA4 ) was recently identified through whole-genome sequencing, but experimental confirmation for its involvement in cadmium resistance is lacking. In this study, we characterized cadA4 in L. monocytogenes strain F8027, a cadmium-resistant strain of serotype 4b. By screening a mariner-based transposon library of this strain, we identified a mutant with reduced tolerance to cadmium and that harbored a single transposon insertion in cadA4 The tolerance to cadmium was restored by genetic complementation with the cadmium resistance cassette ( cadA4C ), and enhanced cadmium tolerance was conferred to two unrelated cadmium-sensitive strains via heterologous complementation with cadA4C Cadmium exposure induced cadA4 expression, even at noninhibitory levels. Virulence assessments in the Galleria mellonella model suggested that a functional cadA4 suppressed virulence, potentially promoting commensal colonization of the insect larvae. Biofilm assays suggested that cadA4 inactivation reduced biofilm formation. These data not only confirm cadA4 as a novel cadmium resistance determinant in L. monocytogenes but also provide evidence for roles in virulence and biofilm formation. IMPORTANCE Listeria monocytogenes is an intracellular foodborne pathogen causing the disease listeriosis, which is responsible for numerous hospitalizations and deaths every year. Among the adaptations that enable the survival of Listeria in the environment are the abilities to persist in biofilms, grow in the cold, and

  9. Ab initio intermolecular potential energy surface and thermophysical properties of hydrogen sulfide.

    Science.gov (United States)

    Hellmann, Robert; Bich, Eckard; Vogel, Eckhard; Vesovic, Velisa

    2011-08-14

    A six-dimensional potential energy hypersurface (PES) for two interacting rigid hydrogen sulfide molecules was determined from high-level quantum-mechanical ab initio computations. A total of 4016 points for 405 different angular orientations of two molecules were calculated utilizing the counterpoise-corrected supermolecular approach at the CCSD(T) level of theory and extrapolating the calculated interaction energies to the complete basis set limit. An analytical site-site potential function with eleven sites per hydrogen sulfide molecule was fitted to the interaction energies. The PES has been validated by computing the second pressure virial coefficient, shear viscosity, thermal conductivity and comparing with the available experimental data. The calculated values of volume viscosity were not used to validate the potential as the low accuracy of the available data precluded such an approach. The second pressure virial coefficient was evaluated by means of the Takahashi and Imada approach, while the transport properties, in the dilute limit, were evaluated by utilizing the classical trajectory method. In general, the agreement with the primary experimental data is within the experimental error for temperatures higher than 300 K. For lower temperatures the lack of reliable data indicates that the values of the second pressure virial coefficient and of the transport properties calculated in this work are currently the most accurate estimates for the thermophysical properties of hydrogen sulfide.

  10. Hypochlorous acid turn-on boron dipyrromethene probe based on oxidation of methyl phenyl sulfide

    International Nuclear Information System (INIS)

    Liu, Shi-Rong; Vedamalai, Mani; Wu, Shu-Pao

    2013-01-01

    Graphical abstract: -- Highlights: •A BODIPY-based green fluorescent probe for sensing HOCl was developed. •The probe utilizes HOCl-promoted oxidation of methyl phenyl sulfide to produce a proportional fluorescence response to the concentration of HOCl. •Confocal fluorescence microscopy imaging of RAW264.7 cells demonstrated that the HCS probe might have application in the investigation of HOCl roles in biological systems. -- Abstract: A boron dipyrromethene (BODIPY)-based fluorometric probe, HCS, has been successfully developed for the highly sensitive and selective detection of hypochlorous acid (HOCl). The probe is based on the specific HOCl-promoted oxidation of methyl phenyl sulfide. The reaction is accompanied by a 160-fold increase in the fluorescent quantum yield (from 0.003 to 0.480). The fluorescent turn-on mechanism is accomplished by suppression of photoinduced electron transfer (PET) from the methyl phenyl sulfide group to BODIPY. The fluorescence intensity of the reaction between HOCl and HCS shows a good linearity in the HOCl concentration range 1–10 μM. The detection limit is 23.7 nM (S/N = 3). In addition, confocal fluorescence microscopy imaging using RAW264.7 macrophages demonstrates that the HCS probe could be an efficient fluorescent detector for HOCl in living cells

  11. Hypochlorous acid turn-on boron dipyrromethene probe based on oxidation of methyl phenyl sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Shi-Rong; Vedamalai, Mani; Wu, Shu-Pao, E-mail: spwu@mail.nctu.edu.tw

    2013-10-24

    Graphical abstract: -- Highlights: •A BODIPY-based green fluorescent probe for sensing HOCl was developed. •The probe utilizes HOCl-promoted oxidation of methyl phenyl sulfide to produce a proportional fluorescence response to the concentration of HOCl. •Confocal fluorescence microscopy imaging of RAW264.7 cells demonstrated that the HCS probe might have application in the investigation of HOCl roles in biological systems. -- Abstract: A boron dipyrromethene (BODIPY)-based fluorometric probe, HCS, has been successfully developed for the highly sensitive and selective detection of hypochlorous acid (HOCl). The probe is based on the specific HOCl-promoted oxidation of methyl phenyl sulfide. The reaction is accompanied by a 160-fold increase in the fluorescent quantum yield (from 0.003 to 0.480). The fluorescent turn-on mechanism is accomplished by suppression of photoinduced electron transfer (PET) from the methyl phenyl sulfide group to BODIPY. The fluorescence intensity of the reaction between HOCl and HCS shows a good linearity in the HOCl concentration range 1–10 μM. The detection limit is 23.7 nM (S/N = 3). In addition, confocal fluorescence microscopy imaging using RAW264.7 macrophages demonstrates that the HCS probe could be an efficient fluorescent detector for HOCl in living cells.

  12. Liquid scintillation counting analysis of cadmium-109

    International Nuclear Information System (INIS)

    Robinson, M.K.; Barfuss, D.W.

    1991-01-01

    Recently the authors have used radiolabled cadmium-109 to measure the transport of inorganic cadmium in renal proximal tubules. An anomaly discovered in the liquid scintillation counting analysis of Cd-109 which is not attributable to normal decay; it consists of a significant decrease in the measured count rate of small amounts of sample. The objective is to determine whether the buffer solution used in the membrane transport studies is causing precipitation of the cadmium or whether cadmium is being adsorbed by the glass. It was important to determine whether the procedure could be modified to correct this problem. The problem does not appear to be related to the use of the buffer or to adsorption of Cd onto glass. Correction based on using triated L-glucose in all of these experiments and calculating a correction factor for the concentration of cadmium

  13. Molecular and cellular mechanisms of cadmium carcinogenesis

    International Nuclear Information System (INIS)

    Waisberg, Michael; Joseph, Pius; Hale, Beverley; Beyersmann, Detmar

    2003-01-01

    Cadmium is a heavy metal, which is widely used in industry, affecting human health through occupational and environmental exposure. In mammals, it exerts multiple toxic effects and has been classified as a human carcinogen by the International Agency for Research on Cancer. Cadmium affects cell proliferation, differentiation, apoptosis and other cellular activities. Cd 2+ does not catalyze Fenton-type reactions because it does not accept or donate electrons under physiological conditions, and it is only weakly genotoxic. Hence, indirect mechanisms are implicated in the carcinogenicity of cadmium. In this review multiple mechanisms are discussed, such as modulation of gene expression and signal transduction, interference with enzymes of the cellular antioxidant system and generation of reactive oxygen species (ROS), inhibition of DNA repair and DNA methylation, role in apoptosis and disruption of E-cadherin-mediated cell-cell adhesion. Cadmium affects both gene transcription and translation. The major mechanisms of gene induction by cadmium known so far are modulation of cellular signal transduction pathways by enhancement of protein phosphorylation and activation of transcription and translation factors. Cadmium interferes with antioxidant defense mechanisms and stimulates the production of reactive oxygen species, which may act as signaling molecules in the induction of gene expression and apoptosis. The inhibition of DNA repair processes by cadmium represents a mechanism by which cadmium enhances the genotoxicity of other agents and may contribute to the tumor initiation by this metal. The disruption of E-cadherin-mediated cell-cell adhesion by cadmium probably further stimulates the development of tumors. It becomes clear that there exist multiple mechanisms which contribute to the carcinogenicity of cadmium, although the relative weights of these contributions are difficult to estimate

  14. Cadmium Diagenesis in Polluted Sediments of a Tropical Estuary of SE Brazil

    Science.gov (United States)

    Patchineelam, S. R.; Metzger, E.; Jézéquel, D.; Sarazin, G.; Smoak, J. M.

    2006-12-01

    Sepetiba bay is a shallow semi enclosed water body located about 70km on the west side of the city of Rio de Janeiro with an area of 450km² separated from the Atlantic Ocean by a sand spit. Fishing, shrimp and tourism are important economic activities. During 35 years a Zinc/Cadmium smelter has polluted the bay. The objective of this investigation is to demonstrate how diagenetic processes are responsible for the cadmium remobilization out or fixation into the sediment column.. Two contrasting sites were selected to compare the diagenetic process. P1 located near to the smelter and P2 is about 20km away from the smelter next to a domestic effluents discharge into the bay. Peeper samplers with 25 cells with a resolution of 2,5cm were introduced into the sediment at both sites. After a period of 3 weeks equilibrium, the pore waters were separated from each cell and analyzed within 24 hours for alkalinity, H2S, NH3 and soluble phosphate by conventional methods An ICP-AES spectrometer was used to analyze Na, Mg, Li, Ba, Sr, Si, Fe and Mn. The total and labile Cd in pore waters were determined by differential-pulse stripping voltammetry. The solute profiles have revealed that the sediments at both sites were anoxic. The slopes of the ferrous and sulfide profile constituents permitted characterization the area at P1 as ferrous dominant with oxic conditions in the overlying water and P2 as a sulfidic rich environment with suboxic conditions in the water column. At P1 total dissolved Cd in the overlying water was about 450pM and labile fraction varied from 85 to 177pM. Just below the sediment water interface 695pM of total dissolved Cd was observed. Probably diagenetic processes are responsible for release of cadmium at the sediment interface. Below this maxima Cd concentrations decreased to 30pM. At P2 a concentration o of 150pM of total dissolved Cd was detected in the overlying water and samples in the pore waters at the sediment interface had an average concentration

  15. Cadmium safety rod thermal tests

    International Nuclear Information System (INIS)

    Thomas, J.K.; Iyer, N.C.; Peacock, H.B.

    1992-01-01

    Thermal testing of cadmium safety rods was conducted as part of a program to define the response of Savannah River Site (SRS) production reactor core components to a hypothetical LOCA leading to a drained reactor tank. The safety rods are present in the reactor core only during shutdown and are not used as a control mechanism during operation; thus, their response to the conditions predicted for the LOCA is only of interest to the extent that it could impact the progression of the accident. This document provides a description of this testing

  16. Testing Cadmium-Free Coatings

    Science.gov (United States)

    2011-08-30

    Secretary of Defense Directive • “Approve the use of alternatives [to hexavalent chromium (Cr6+)] where they can perform adequately for the intended...Effect of corrosion on breakaway torque 12 OPSEC approved for public release Fastener Finish Study FINISH POST-TREATMENT LUBRICANT Cadmium Hexavalent ...Past Testing Electrical Connectors Coatings Al / TCP ZnNi / TCP ZnNi / Non- Chrome Passivation (NCP) Ni-PTFE 1 Ni-PTFE 2 Note: SnZn tested on flat

  17. Hydrogen sulfide concentration in Beaver Dam Creek

    International Nuclear Information System (INIS)

    Kiser, D.L.

    1979-01-01

    Concentration-time profiles calculated with LODIPS for various hypothetical releases of hydrogen sulfide from the heavy water extraction facility predict lethal conditions for swamp fish from releases as small as 568 kg discharged over a period of 30 minutes or from releases of 1818 kg discharged over a period of 6 hours or less. The necessary volatilization and oxidation coefficients for LODIPS were derived from field measurements following planned releases of H 2 S. Upsets in the operation of the wastewater strippers in the Girdler-Sulfide (GS) heavy water extraction facility in D Area have released significant amounts of dissolved H 2 S to Beaver Dam Creek. Because H 2 S is toxic to fish in concentrations as low as 1 mg/liter, the downstream environmental impact of H 2 S releases from D Area was evaluated

  18. Iron-sulfide redox flow batteries

    Science.gov (United States)

    Xia, Guan-Guang; Yang, Zhenguo; Li, Liyu; Kim, Soowhan; Liu, Jun; Graff, Gordon L

    2013-12-17

    Iron-sulfide redox flow battery (RFB) systems can be advantageous for energy storage, particularly when the electrolytes have pH values greater than 6. Such systems can exhibit excellent energy conversion efficiency and stability and can utilize low-cost materials that are relatively safer and more environmentally friendly. One example of an iron-sulfide RFB is characterized by a positive electrolyte that comprises Fe(III) and/or Fe(II) in a positive electrolyte supporting solution, a negative electrolyte that comprises S.sup.2- and/or S in a negative electrolyte supporting solution, and a membrane, or a separator, that separates the positive electrolyte and electrode from the negative electrolyte and electrode.

  19. Quantum walks, quantum gates, and quantum computers

    International Nuclear Information System (INIS)

    Hines, Andrew P.; Stamp, P. C. E.

    2007-01-01

    The physics of quantum walks on graphs is formulated in Hamiltonian language, both for simple quantum walks and for composite walks, where extra discrete degrees of freedom live at each node of the graph. It is shown how to map between quantum walk Hamiltonians and Hamiltonians for qubit systems and quantum circuits; this is done for both single-excitation and multiexcitation encodings. Specific examples of spin chains, as well as static and dynamic systems of qubits, are mapped to quantum walks, and walks on hyperlattices and hypercubes are mapped to various gate systems. We also show how to map a quantum circuit performing the quantum Fourier transform, the key element of Shor's algorithm, to a quantum walk system doing the same. The results herein are an essential preliminary to a Hamiltonian formulation of quantum walks in which coupling to a dynamic quantum environment is included

  20. Hydrogen sulfide prodrugs—a review

    Directory of Open Access Journals (Sweden)

    Yueqin Zheng

    2015-09-01

    Full Text Available Hydrogen sulfide (H2S is recognized as one of three gasotransmitters together with nitric oxide (NO and carbon monoxide (CO. As a signaling molecule, H2S plays an important role in physiology and shows great potential in pharmaceutical applications. Along this line, there is a need for the development of H2S prodrugs for various reasons. In this review, we summarize different H2S prodrugs, their chemical properties, and some of their potential therapeutic applications.

  1. Effect of Al 2 O 3 Recombination Barrier Layers Deposited by Atomic Layer Deposition in Solid-State CdS Quantum Dot-Sensitized Solar Cells

    KAUST Repository

    Roelofs, Katherine E.

    2013-03-21

    Despite the promise of quantum dots (QDs) as a light-absorbing material to replace the dye in dye-sensitized solar cells, quantum dot-sensitized solar cell (QDSSC) efficiencies remain low, due in part to high rates of recombination. In this article, we demonstrate that ultrathin recombination barrier layers of Al2O3 deposited by atomic layer deposition can improve the performance of cadmium sulfide (CdS) quantum dot-sensitized solar cells with spiro-OMeTAD as the solid-state hole transport material. We explored depositing the Al2O3 barrier layers either before or after the QDs, resulting in TiO2/Al2O3/QD and TiO 2/QD/Al2O3 configurations. The effects of barrier layer configuration and thickness were tracked through current-voltage measurements of device performance and transient photovoltage measurements of electron lifetimes. The Al2O3 layers were found to suppress dark current and increase electron lifetimes with increasing Al 2O3 thickness in both configurations. For thin barrier layers, gains in open-circuit voltage and concomitant increases in efficiency were observed, although at greater thicknesses, losses in photocurrent caused net decreases in efficiency. A close comparison of the electron lifetimes in TiO2 in the TiO2/Al2O3/QD and TiO2/QD/Al2O3 configurations suggests that electron transfer from TiO2 to spiro-OMeTAD is a major source of recombination in ss-QDSSCs, though recombination of TiO2 electrons with oxidized QDs can also limit electron lifetimes, particularly if the regeneration of oxidized QDs is hindered by a too-thick coating of the barrier layer. © 2013 American Chemical Society.

  2. Relation between dietary cadmium intake and biomarkers of cadmium exposure in premenopausal women accounting for body iron stores

    Directory of Open Access Journals (Sweden)

    Julin Bettina

    2011-12-01

    Full Text Available Abstract Background Cadmium is a widespread environmental pollutant with adverse effects on kidneys and bone, but with insufficiently elucidated public health consequences such as risk of end-stage renal diseases, fractures and cancer. Urinary cadmium is considered a valid biomarker of lifetime kidney accumulation from overall cadmium exposure and thus used in the assessment of cadmium-induced health effects. We aimed to assess the relationship between dietary cadmium intake assessed by analyses of duplicate food portions and cadmium concentrations in urine and blood, taking the toxicokinetics of cadmium into consideration. Methods In a sample of 57 non-smoking Swedish women aged 20-50 years, we assessed Pearson's correlation coefficients between: 1 Dietary intake of cadmium assessed by analyses of cadmium in duplicate food portions collected during four consecutive days and cadmium concentrations in urine, 2 Partial correlations between the duplicate food portions and urinary and blood cadmium concentrations, respectively, and 3 Model-predicted urinary cadmium concentration predicted from the dietary intake using a one-compartment toxicokinetic model (with individual data on age, weight and gastrointestinal cadmium absorption and urinary cadmium concentration. Results The mean concentration of cadmium in urine was 0.18 (+/- s.d.0.12 μg/g creatinine and the model-predicted urinary cadmium concentration was 0.19 (+/- s.d.0.15 μg/g creatinine. The partial Pearson correlations between analyzed dietary cadmium intake and urinary cadmium or blood concentrations were r = 0.43 and 0.42, respectively. The correlation between diet and urinary cadmium increased to r = 0.54 when using a one-compartment model with individual gastrointestinal cadmium absorption coefficients based on the women's iron status. Conclusions Our results indicate that measured dietary cadmium intake can reasonably well predict biomarkers of both long-term kidney accumulation

  3. Light-emitting diodes based on nontoxic zinc-alloyed silver-indium-sulfide (AIZS) nanocrystals

    Science.gov (United States)

    Bhaumik, Saikat; Guchhait, Asim; Pal, Amlan J.

    2014-04-01

    We report solution-processed growth of zinc-alloyed silver-indium-sulfide (AIZS) nanocrystals followed by fabrication and characterization of light-emitting diodes (LEDs) based on such nanostructures. While growing the low dimensional crystals, we vary the ratio between the silver and zinc contents that in turn tunes the bandgap and correspondingly their photoluminescence (PL) emission. We also dope the AIZS nanocrystals with manganese, so that their PL emission, which appears due to a radiative transition between the d-states of the dopants, becomes invariant in energy when the diameter of the quantum dots or the dopant concentration in the nanostructures varies. The LEDs fabricated with such undoped and manganese-doped AIZS nanocrystals emit electroluminescence (EL) that matches the PL spectrum of the respective nanomaterial. The results demonstrate examples of quantum dot LEDs (QDLEDs) based on nontoxic AIZS nanocrystals.

  4. Molecular Dynamics Simulation and Analysis of Interfacial Water at Selected Sulfide Mineral Surfaces under Anaerobic Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Jiaqi; Miller, Jan D.; Dang, Liem X.

    2014-04-10

    In this paper, we report on a molecular dynamics simulation (MDS) study of the behavior of interfacial water at selected sulfide mineral surfaces under anaerobic conditions. The study revealed the interfacial water structure and wetting characteristics of the pyrite (100) surface, galena (100) surface, chalcopyrite (012) surface, sphalerite (110) surface, and molybdenite surfaces (i.e., the face, armchair-edge, and zigzag-edge surfaces), including simulated contact angles, relative number density profiles, water dipole orientations, hydrogen-bonding, and residence times. For force fields of the metal and sulfur atoms in selected sulfide minerals used in the MDS, we used the universal force field (UFF) and another set of force fields optimized by quantum chemical calculations for interactions with interfacial water molecules at selected sulfide mineral surfaces. Simulation results for the structural and dynamic properties of interfacial water molecules indicate the natural hydrophobic character for the selected sulfide mineral surfaces under anaerobic conditions as well as the relatively weak hydrophobicity for the sphalerite (110) surface and two molybdenite edge surfaces. Part of the financial support for this study was provided by the U.S. Department of Energy (DOE) under Basic Science Grant No. DE-FG-03-93ER14315. The Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences (BES), of the DOE, funded work performed by Liem X. Dang. Battelle operates Pacific Northwest National Laboratory for DOE. The calculations were carried out using computer resources provided by BES. The authors are grateful to Professor Tsun-Mei Chang for valuable discussions.

  5. Quantum memory Quantum memory

    Science.gov (United States)

    Le Gouët, Jean-Louis; Moiseev, Sergey

    2012-06-01

    Interaction of quantum radiation with multi-particle ensembles has sparked off intense research efforts during the past decade. Emblematic of this field is the quantum memory scheme, where a quantum state of light is mapped onto an ensemble of atoms and then recovered in its original shape. While opening new access to the basics of light-atom interaction, quantum memory also appears as a key element for information processing applications, such as linear optics quantum computation and long-distance quantum communication via quantum repeaters. Not surprisingly, it is far from trivial to practically recover a stored quantum state of light and, although impressive progress has already been accomplished, researchers are still struggling to reach this ambitious objective. This special issue provides an account of the state-of-the-art in a fast-moving research area that makes physicists, engineers and chemists work together at the forefront of their discipline, involving quantum fields and atoms in different media, magnetic resonance techniques and material science. Various strategies have been considered to store and retrieve quantum light. The explored designs belong to three main—while still overlapping—classes. In architectures derived from photon echo, information is mapped over the spectral components of inhomogeneously broadened absorption bands, such as those encountered in rare earth ion doped crystals and atomic gases in external gradient magnetic field. Protocols based on electromagnetic induced transparency also rely on resonant excitation and are ideally suited to the homogeneous absorption lines offered by laser cooled atomic clouds or ion Coulomb crystals. Finally off-resonance approaches are illustrated by Faraday and Raman processes. Coupling with an optical cavity may enhance the storage process, even for negligibly small atom number. Multiple scattering is also proposed as a way to enlarge the quantum interaction distance of light with matter. The

  6. Synthesis and application of luminescent single CdS quantum dot encapsulated silica nanoparticles directed for precision optical bioimaging

    Directory of Open Access Journals (Sweden)

    Veeranarayanan S

    2012-07-01

    Full Text Available Srivani Veeranarayanan, Aby Cheruvathoor Poulose, M Sheikh Mohamed, Yutaka Nagaoka, Seiki Iwai, Yuya Nakagame, Shosaku Kashiwada, Yasuhiko Yoshida, Toru Maekawa, D Sakthi KumarBio Nano Electronics Research Centre, Graduate School of Interdisciplinary New Science, Toyo University, Kawagoe, JapanAbstract: This paper presents the synthesis of aqueous cadmium sulfide (CdS quantum dots (QDs and silica-encapsulated CdS QDs by reverse microemulsion method and utilized as targeted bio-optical probes. We report the role of CdS as an efficient cell tag with fluorescence on par with previously documented cadmium telluride and cadmium selenide QDs, which have been considered to impart high levels of toxicity. In this study, the toxicity of bare QDs was efficiently quenched by encapsulating them in a biocompatible coat of silica. The toxicity profile and uptake of bare CdS QDs and silica-coated QDs, along with the CD31-labeled, silica-coated CdS QDs on human umbilical vein endothelial cells and glioma cells, were investigated. The effect of size, along with the time-dependent cellular uptake of the nanomaterials, has also been emphasized. Enhanced, high-specificity imaging toward endothelial cell lines in comparison with glioma cells was achieved with CD31 antibody-conjugated nanoparticles. The silica-coated nanomaterials exhibited excellent biocompatibility and greater photostability inside live cells, in addition to possessing an extended shelf life. In vivo biocompatibility and localization study of silica-coated CdS QDs in medaka fish embryos, following direct nanoparticle exposure for 24 hours, authenticated the nanomaterials' high potential for in vivo imaging, augmented with superior biocompatibility. As expected, CdS QD-treated embryos showed 100% mortality, whereas the silica-coated QD-treated embryos stayed viable and healthy throughout and after the experiments, devoid of any deformities. We provide highly cogent and convincing evidence for such

  7. Influence of protein deficiency on cadmium toxicity in rats

    Energy Technology Data Exchange (ETDEWEB)

    Tewari, P C; Jain, V K; Ashquin, M; Tandon, S K

    1986-07-01

    The effects of a low protein diet on the body uptake and retention of cadmium, levels of essential trace elements, and cadmium-induced biochemical alterations in liver and kidneys of the rat were investigated. Low dietary protein disturbs cadmium induced alterations in carbohydrate metabolism, essential trace elements metabolism and offsets the hepatic and renal process of cadmium detoxification. Protein malnutrition enhances the susceptibility to cadmium intoxication.

  8. Cadmium Exposure is Associated with the Prevalence of Dyslipidemia.

    Science.gov (United States)

    Zhou, Zhou; Lu, Yong-Hui; Pi, Hui-Feng; Gao, Peng; Li, Min; Zhang, Lei; Pei, Li-Ping; Mei, Xiang; Liu, Lin; Zhao, Qi; Qin, Qi-Zhong; Chen, Yu; Jiang, Yue-Ming; Zhang, Zhao-Hui; Yu, Zheng-Ping

    2016-01-01

    Cadmium is a widespread environmental and occupational pollutant that accumulates in human body with a biological half-life exceeding 10 years. Cadmium exposure has been demonstrated to increase rates of cardiovascular diseases. Whether occupational cadmium exposure is associated with the increase in the prevalence of dyslipidemia and hence contributes to the risk of cardiovascular diseases is still equivocal. To test the hypothesis that exposure to cadmium is related to the prevalence of dyslipidemia, we examined the associations between blood cadmium concentration and the prevalence of dyslipidemia in workers occupationally exposed to cadmium in China. A cross-sectional survey on demographic data, blood cadmium level and lipid profile in cadmium exposed workers from seven cadmium smelting factories in central and southwestern China was conducted. We measured blood cadmium concentration and lipid components of 1489 cadmium exposed workers. The prevalence of dyslipidemia was compared across blood cadmium quartiles. Associations between the blood cadmium concentrations and the prevalence of dyslipidemia were assessed using confounder adjusted linear and logistic regressions. The blood cadmium concentration was 3.61±0.84µg/L ( mean ±SD). The prevalence of dyslipidemia in this occupational population was 66.3%. Mean blood cadmium concentration of workers with dyslipedemia was significantly higher than that of workers without dyslipidemia (p dyslipidemia increased dose-dependently with elevations in blood cadmium concentrations (p for trend dyslipidemia across the increasing blood cadmium quartiles were 1.21(1.16-1.55), 1.56(1.11-1.87), 1.79(1.26-2.25) respectively (referencing to 1.00; p for trend dyslipidemia remained unchanged (all p for trend dyslipidemia. Cadmium exposure could alter lipid metabolism in humans. It is imperative to control cadmium exposure of occupational population in cadmium related industries and reduce adverse health effects. © 2016 The

  9. Radiochemical separation of cadmium-109

    International Nuclear Information System (INIS)

    Egamediev, S.; Mukhtarov, A.; Nurbaeva, D.; Rakhmanov, A.

    2006-01-01

    Full text: Cadmium-109 has a half-life of 461.9 days and decays by electron capture to 109 Ag with the emission of 88 keV γ-ray (3.79%) along with the characteristic X-ray from the K level of Ag, with energy of 22.5 keV. This radionuclide has found widespread use as a photon source in x-ray fluorescence analysis devices employed in industry for numerous applications such as the direct determination of gold in ores, the analysis of metals and identification of steels. Other applications range from its use as an electron source for measurement of densities of air-pollution samples, to tracer studies in mushrooms and mice and rats. In the nuclear medicine field there is growing interest in employing 109 Cd in a 109 Cd/ 109mA g generator, as an alternative to other biomedical generators of ultra short-lived gamma emitters. There are several methods for the production of 109 Cd in literature: 1. Bombardment of silver cyclotron target via 109 Ag(d,2n) 109 Cd reaction with 16 MeV deuterons. 2. Bombardment of natural silver target via 109 Ag(p,n) 109 Cd reaction with 14 MeV protons. 3. Proton bombardment of natural indium target with 96 MeV protons. 4. Irradiation of enriched 107 Ag target in high-flux nuclear reactor at neutron flux 2x10 15 n·cm -2 ·s -1 via 107 Ag(n,γ) 108 Ag → 108 Cd (n,γ) 109 Cd reaction. 5. Irradiation of enriched 108 Cd target in nuclear reactor at neutron flux 1x10 14 n·cm -2 ·s -1 via 108 Cd (n,γ) 109 Cd reaction. The production of 109 Cd with proton beam via 109 Ag(p,n) 109 Cd reaction is ideal for the cyclotron U-150, since it is not required the change of the regime for the machine functioning. Because of its relatively long half-life the time required for separation is also not an important factor, but its use as an X-ray source requires a very high radiochemical purity. In the present work we studied two methods for separation of 109 Cd from model solution of silver targets. First method is based on precipitation of silver as

  10. Simultaneous removal of sulfide, nitrate and acetate: Kinetic modeling

    International Nuclear Information System (INIS)

    Wang Aijie; Liu Chunshuang; Ren Nanqi; Han Hongjun; Lee Duujong

    2010-01-01

    Biological removal of sulfide, nitrate and chemical oxygen demand (COD) simultaneously from industrial wastewaters to elementary sulfur (S 0 ), N 2 , and CO 2 , or named the denitrifying sulfide (DSR) process, is a cost effective and environmentally friendly treatment process for high strength sulfide and nitrate laden organic wastewater. Kinetic model for the DSR process was established for the first time on the basis of Activated Sludge Model No. 1 (ASM1). The DSR experiments were conducted at influent sulfide concentrations of 200-800 mg/L, whose results calibrate the model parameters. The model correlates well with the DSR process dynamics. By introducing the switch function and the inhibition function, the competition between autotrophic and heterotrophic denitrifiers is quantitatively described and the degree of inhibition of sulfide on heterotrophic denitrifiers is realized. The model output indicates that the DSR reactor can work well at 0.5 1000 mg/L influent sulfide, however, the DSR system will break down.

  11. Microaeration for hydrogen sulfide removal in UASB reactor.

    Science.gov (United States)

    Krayzelova, Lucie; Bartacek, Jan; Kolesarova, Nina; Jenicek, Pavel

    2014-11-01

    The removal of hydrogen sulfide from biogas by microaeration was studied in Up-flow Anaerobic Sludge Blanket (UASB) reactors treating synthetic brewery wastewater. A fully anaerobic UASB reactor served as a control while air was dosed into a microaerobic UASB reactor (UMSB). After a year of operation, sulfur balance was described in both reactors. In UASB, sulfur was mainly presented in the effluent as sulfide (49%) and in biogas as hydrogen sulfide (34%). In UMSB, 74% of sulfur was detected in the effluent (41% being sulfide and 33% being elemental sulfur), 10% accumulated in headspace as elemental sulfur and 9% escaped in biogas as hydrogen sulfide. The efficiency of hydrogen sulfide removal in UMSB was on average 73%. Microaeration did not cause any decrease in COD removal or methanogenic activity in UMSB and the elemental sulfur produced by microaeration did not accumulate in granular sludge. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Reduction of produced elementary sulfur in denitrifying sulfide removal process.

    Science.gov (United States)

    Zhou, Xu; Liu, Lihong; Chen, Chuan; Ren, Nanqi; Wang, Aijie; Lee, Duu-Jong

    2011-05-01

    Denitrifying sulfide removal (DSR) processes simultaneously convert sulfide, nitrate, and chemical oxygen demand from industrial wastewater into elemental sulfur, dinitrogen gas, and carbon dioxide, respectively. The failure of a DSR process is signaled by high concentrations of sulfide in reactor effluent. Conventionally, DSR reactor failure is blamed for overcompetition for heterotroph to autotroph communities. This study indicates that the elementary sulfur produced by oxidizing sulfide that is a recoverable resource from sulfide-laden wastewaters can be reduced back to sulfide by sulfur-reducing Methanobacterium sp. The Methanobacterium sp. was stimulated with excess organic carbon (acetate) when nitrite was completely consumed by heterotrophic denitrifiers. Adjusting hydraulic retention time of a DSR reactor when nitrite is completely consumed provides an additional control variable for maximizing DSR performance.

  13. Study on the sulfidation behavior of smithsonite

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Dandan; Wen, Shuming, E-mail: shmwen@126.com; Deng, Jiushuai, E-mail: dengshuai689@163.com; Liu, Jian; Mao, Yingbo

    2015-02-28

    Highlights: • Zeta potential showed that the pH{sub IEP} of smithsonite decreased from 7.7 to 6. • ICP test showed the gradual reduction of C{sub S} in the solution. • SEM showed that the mineral surface was partially changed to ZnS film. • XPS indicated that the presence of a characteristic signal peak of sulfur ions. - Abstract: Zinc extraction from low-grade mineral resources of oxidized zinc has recently become a focus of study. Sulfidation is an important process in oxidized ore flotation. In this study, the influence of sulfur ion adsorption on smithsonite surface was investigated with the use of zeta potential, inductively coupled plasma (ICP), scanning electron microscope (SEM), and X-ray photoelectron spectroscopic studies. Zeta potential measurements of sodium sulfide showed that sulfur ions were adsorbed onto the surface of pure smithsonite, as evidenced by the increased negative charge and the decrease in the pH{sub IEP} of smithsonite from 7.7 to 6 after sodium sulfide treatment. The ICP test revealed the gradual reduction in sulfur ion adsorption onto the surface of smithsonite in pulp sulfur. After 30 min of absorption, C{sub S} in the solution declined from 1000 × 10{sup −6} mol/L to 1.4 × 10{sup −6} mol/L. SEM results showed that the mineral surface was partially changed to ZnS film after sodium sulfide treatment, whereas EDS analysis results showed that 2% S is contained on the smithsonite surface. X-ray photoelectron spectroscopy results indicated the presence of a characteristic signal peak of sulfur ions after sulfidation. Sulfur concentration increased to 11.89%, whereas oxygen concentration decreased from 42.31% to 13.74%. Sulfur ions were not only present during chemical adsorption, but were also incorporated into the crystal lattices of minerals by the exchange reaction between S{sup 2−} and CO{sub 3}{sup 2−} ions.

  14. Cadmium action in synapses in the brain

    Energy Technology Data Exchange (ETDEWEB)

    Minami, Akira; Takeda, Atsushi; Nishibaba, Daisuke; Tekefuta, Sachiyo; Oku, Naoto [Department of Radiobiochemistry, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka (Japan)

    2001-05-01

    Chronic exposure to cadmium causes central nervous system disorders, e.g., olfactory dysfunction. To clarify cadmium toxicity in synaptic neurotransmission in the brain, the movement and action of cadmium in the synapses was examined using in vivo microdialysis. One and 24 h after injection of {sup 109}CdCl{sub 2} into the amygdala of rats, {sup 109}Cd release into the extracellular space was facilitated by stimulation with high K{sup +}, suggesting that cadmium taken up in amygdalar neurons is released into the synaptic clefts in a calcium- and impulse-dependent manner. To examine the action of cadmium in the synapses, the amygdala was perfused with artificial cerebrospinal fluid containing 10-30 {mu}M CdCl{sub 2}. The release of excitatory neurotransmitters, i.e., glutamate and aspartate, into the extracellular space was decreased during perfusion with cadmium, while the release of inhibitory neurotransmitters, i.e., glycine and {gamma}-amino butyric acid (GABA), into the extracellular space was increased during the period. These results suggest that cadmium released from the amygdalar neuron terminals affects the degree and balance of excitation-inhibition in synaptic neurotransmission. (author)

  15. Cadmium action in synapses in the brain

    International Nuclear Information System (INIS)

    Minami, Akira; Takeda, Atsushi; Nishibaba, Daisuke; Tekefuta, Sachiyo; Oku, Naoto

    2001-01-01

    Chronic exposure to cadmium causes central nervous system disorders, e.g., olfactory dysfunction. To clarify cadmium toxicity in synaptic neurotransmission in the brain, the movement and action of cadmium in the synapses was examined using in vivo microdialysis. One and 24 h after injection of 109 CdCl 2 into the amygdala of rats, 109 Cd release into the extracellular space was facilitated by stimulation with high K + , suggesting that cadmium taken up in amygdalar neurons is released into the synaptic clefts in a calcium- and impulse-dependent manner. To examine the action of cadmium in the synapses, the amygdala was perfused with artificial cerebrospinal fluid containing 10-30 μM CdCl 2 . The release of excitatory neurotransmitters, i.e., glutamate and aspartate, into the extracellular space was decreased during perfusion with cadmium, while the release of inhibitory neurotransmitters, i.e., glycine and γ-amino butyric acid (GABA), into the extracellular space was increased during the period. These results suggest that cadmium released from the amygdalar neuron terminals affects the degree and balance of excitation-inhibition in synaptic neurotransmission. (author)

  16. Cadmium - a case of mistaken identity

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, D

    1984-05-01

    New evidence is presented which describes the impact of cadmium in the environment. Cadmium is a persistent material, although its compounds may undergo a range of chemical changes in the environment. In soluble form cadmium and its compounds are toxic at relatively low concentrations to aquatic animals although their bioconcentrations in such animals is in general low, and there is no evidence of biomagnification. In insoluble form cadmium and its compounds are relatively non-toxic to aquatic animals and are unlikely to be bioconcentrated. As such, cadmium is similar to most other heavy metals. Recent studies indicate that cadmium is not implicated in Itai-Itai disease and does not appear to cause hypertension or cancer. In addition, the accepted critical level in the kidney may have been underestimated. Thus, the hazard to man appears to be considerably less than the original estimates. In view of these data, there seems little justification in treating cadmium in any way differently from the other metals and hence no reason for retaining it on the Black List of the international conventions. 19 references.

  17. Response of Saccharomyces cerevisiae to cadmium stress

    International Nuclear Information System (INIS)

    Moreira, Luciana Mara Costa; Ribeiro, Frederico Haddad; Neves, Maria Jose; Porto, Barbara Abranches Araujo; Amaral, Angela M.; Menezes, Maria Angela B.C.; Rosa, Carlos Augusto

    2009-01-01

    The intensification of industrial activity has been greatly contributing with the increase of heavy metals in the environment. Among these heavy metals, cadmium becomes a serious pervasive environmental pollutant. The cadmium is a heavy metal with no biological function, very toxic and carcinogenic at low concentrations. The toxicity of cadmium and several other metals can be mainly attributed to the multiplicity of coordination complexes and clusters that they can form. Some aspects of the cellular response to cadmium were extensively investigated in the yeast Saccharomyces cerevisiae. The primary site of interaction between many toxic metals and microbial cells is the plasma membrane. Plasma-membrane permeabilisation has been reported in a variety of microorganisms following cadmium exposure, and is considered one mechanism of cadmium toxicity in the yeast. In this work, using the yeast strain S. cerevisiae W303-WT, we have investigated the relationships between Cd uptake and release of cellular metal ions (K + and Na + ) using neutron activation technique. The neutron activation was an easy, rapid and suitable technique for doing these metal determinations on yeast cells; was observed the change in morphology of the strains during the process of Cd accumulation, these alterations were observed by Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) during incorporation of cadmium. (author)

  18. Response of Saccharomyces cerevisiae to cadmium stress

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Luciana Mara Costa; Ribeiro, Frederico Haddad; Neves, Maria Jose [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Lab. de Radiobiologia], e-mail: luamatu@uol.com.br; Porto, Barbara Abranches Araujo; Amaral, Angela M.; Menezes, Maria Angela B.C. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Lab. de Ativacao Neutronica], e-mail: menezes@cdtn.br; Rosa, Carlos Augusto [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Microbiologia], e-mail: carlrosa@icb.ufmg

    2009-07-01

    The intensification of industrial activity has been greatly contributing with the increase of heavy metals in the environment. Among these heavy metals, cadmium becomes a serious pervasive environmental pollutant. The cadmium is a heavy metal with no biological function, very toxic and carcinogenic at low concentrations. The toxicity of cadmium and several other metals can be mainly attributed to the multiplicity of coordination complexes and clusters that they can form. Some aspects of the cellular response to cadmium were extensively investigated in the yeast Saccharomyces cerevisiae. The primary site of interaction between many toxic metals and microbial cells is the plasma membrane. Plasma-membrane permeabilisation has been reported in a variety of microorganisms following cadmium exposure, and is considered one mechanism of cadmium toxicity in the yeast. In this work, using the yeast strain S. cerevisiae W303-WT, we have investigated the relationships between Cd uptake and release of cellular metal ions (K{sup +} and Na{sup +}) using neutron activation technique. The neutron activation was an easy, rapid and suitable technique for doing these metal determinations on yeast cells; was observed the change in morphology of the strains during the process of Cd accumulation, these alterations were observed by Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) during incorporation of cadmium. (author)

  19. Epidemiological approach to cadmium pollution in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Shigematsu, I.

    1984-04-01

    The study of health problems due to cadmium pollution in Japan originated from an endemic episode of Itai-itai disease in a rural area in north-central Japan after World War II. The disease was defined as osteomalacia with tubular changes in the kidney and considered to be associated with excess intake of cadmium. This episode motivated the Japanese Government to conduct health examinations on the general population in cadmium-polluted and non-polluted areas throughout the country since 1969. Although Itai-itai disease-like bone changes were rarely found, these studies revealed a higher prevalence of renal tubular dysfunction among elderly people in the cadmium-polluted areas. No significant difference was noted in cancer mortality, but mortality from cardiovascular diseases and all causes tended to be lower in cadmium-polluted areas. Clinical and pathological studies in man as well as experiments on primates have recently been made to elucidate the pathogenesis of Itai-itai disease and the health effects of cadmium. The lack of knowledge on the ecological and biological complex of cadmium resulted in the impediment of studies on this problem. The lesson from this experience is that basic research is essential for promoting the study of pollutants such as heavy metals, though pollution problems usually require urgent solutions.

  20. Quantum stochastics

    CERN Document Server

    Chang, Mou-Hsiung

    2015-01-01

    The classical probability theory initiated by Kolmogorov and its quantum counterpart, pioneered by von Neumann, were created at about the same time in the 1930s, but development of the quantum theory has trailed far behind. Although highly appealing, the quantum theory has a steep learning curve, requiring tools from both probability and analysis and a facility for combining the two viewpoints. This book is a systematic, self-contained account of the core of quantum probability and quantum stochastic processes for graduate students and researchers. The only assumed background is knowledge of the basic theory of Hilbert spaces, bounded linear operators, and classical Markov processes. From there, the book introduces additional tools from analysis, and then builds the quantum probability framework needed to support applications to quantum control and quantum information and communication. These include quantum noise, quantum stochastic calculus, stochastic quantum differential equations, quantum Markov semigrou...

  1. Quantum dot solar cell

    International Nuclear Information System (INIS)

    Ahamefula, U.C.; Sulaiman, M.Y.; Sopian, K.; Ibarahim, Z.; Ibrahim, N.; Alghoul, M.A.; Haw, L.C.; Yahya, M.; Amin, N.; Mat, S.; Ruslan, M.H.

    2009-01-01

    Full text: The much awaited desire of replacing fossil fuel with photovoltaic will remain a fairy tale if the myriad of issues facing solar cell development are marginalized. Foremost in the list is the issue of cost. Silicon has reached a stage where its use on large scale can no longer be lavishly depended upon. The demand for high grade silicon from the microelectronics and solar industries has soared leading to scarcity. New approach has to be sought. Notable is the increased attention on thin films such as cadmium telluride, copper indium gallium diselenide, amorphous silicon, and the not so thin non-crystalline family of silicon. While efforts to address the issues of stability, toxicity and efficiency of these systems are ongoing, another novel approach is quietly making its appearance - quantum dots. Quantum dots seem to be promising candidates for solar cells because of the opportunity to manipulate their energy levels allowing absorption of a wider solar spectrum. Utilization of minute quantity of these nano structures is enough to bring the cost of solar cell down and to ascertain sustainable supply of useful material. The paper outlines the progress that has been made on quantum dot solar cells. (author)

  2. Quantum Computing

    OpenAIRE

    Scarani, Valerio

    1998-01-01

    The aim of this thesis was to explain what quantum computing is. The information for the thesis was gathered from books, scientific publications, and news articles. The analysis of the information revealed that quantum computing can be broken down to three areas: theories behind quantum computing explaining the structure of a quantum computer, known quantum algorithms, and the actual physical realizations of a quantum computer. The thesis reveals that moving from classical memor...

  3. Quantum Malware

    OpenAIRE

    Wu, Lian-Ao; Lidar, Daniel A.

    2005-01-01

    When quantum communication networks proliferate they will likely be subject to a new type of attack: by hackers, virus makers, and other malicious intruders. Here we introduce the concept of "quantum malware" to describe such human-made intrusions. We offer a simple solution for storage of quantum information in a manner which protects quantum networks from quantum malware. This solution involves swapping the quantum information at random times between the network and isolated, distributed an...

  4. Cadmium decontamination using in-house resin

    International Nuclear Information System (INIS)

    Pal, Sangita; Thalor, K.L; Prabhakar, S.; Srivastava, V.K.; Goswami, J.L.; Tewari, P.K.; Dhanpal, Pranav; Goswami, J.L.

    2010-01-01

    A selective and strong in-house chelator has been studied w.r.t. basic parameters like concentration, time, and elution. De-contamination of cadmium, mercury, chromium, lead etc by using high uptake values fro cadmium ions proves its selectivity with high elution ratio ensures further decontamination of run-off water during natural calamities. In three step cascade use the concentration of original cadmium solution (500 ppm) decocted to safe disposable attribute. This polymeric ligand exchanger displayed outlet effluent concentration to 1 ppm and less than 200 ppb when treated for inlet feed concentration of 50 ppm and 500 ppm respectively. (author)

  5. Lead and cadmium content of spices

    Energy Technology Data Exchange (ETDEWEB)

    Bielig, H J; Dreyer, H; Askar, A

    1977-02-02

    The lead and cadmium content of various spices was determined by flameless atomic absorption (AAS). With the exception of one sample, the lead content was lower than 5 ppm, averaging a value of 2,2 ppm Pb. Thus, the maximum permissible level of 5 ppm Pb as recommended by different DIN standards, is not exceeded. The cadmium content was - except for one sample - lower than 0,5 ppm averaging a value of 0,23 ppm Cd. It can be assumed, that by spicing our dishes, the ingestion of lead and cadmium stays at a low level.

  6. Quantumness beyond quantum mechanics

    International Nuclear Information System (INIS)

    Sanz, Ángel S

    2012-01-01

    Bohmian mechanics allows us to understand quantum systems in the light of other quantum traits than the well-known ones (coherence, diffraction, interference, tunnelling, discreteness, entanglement, etc.). Here the discussion focusses precisely on two of these interesting aspects, which arise when quantum mechanics is thought within this theoretical framework: the non-crossing property, which allows for distinguishability without erasing interference patterns, and the possibility to define quantum probability tubes, along which the probability remains constant all the way. Furthermore, taking into account this hydrodynamic-like description as a link, it is also shown how this knowledge (concepts and ideas) can be straightforwardly transferred to other fields of physics (for example, the transmission of light along waveguides).

  7. Amphiphilic Quantum Dots with Asymmetric, Mixed Polymer Brush Layers: From Single Core-Shell Nanoparticles to Salt-Induced Vesicle Formation

    Directory of Open Access Journals (Sweden)

    Brian R. Coleman

    2018-03-01

    Full Text Available A mixed micelle approach is used to produce amphiphilic brush nanoparticles (ABNPs with cadmium sulfide quantum dot (QD cores and surface layers of densely grafted (σ = ~1 chain/nm2 and asymmetric (fPS = 0.9 mixed polymer brushes that contain hydrophobic polystyrene (PS and hydrophilic poly(methyl methacrylate (PMAA chains (PS/PMAA-CdS. In aqueous media, the mixed brushes undergo conformational rearrangements that depend strongly on prior salt addition, giving rise to one of two pathways to fluorescent and morphologically disparate QD-polymer colloids. (A In the absence of salt, centrosymmetric condensation of PS chains forms individual core-shell QD-polymer colloids. (B In the presence of salt, non-centrosymmetric condensation of PS chains forms Janus particles, which trigger anisotropic interactions and amphiphilic self-assembly into the QD-polymer vesicles. To our knowledge, this is the first example of an ABNP building block that can form either discrete core-shell colloids or self-assembled superstructures in water depending on simple changes to the chemical conditions (i.e., salt addition. Such dramatic and finely tuned morphological variation could inform numerous applications in sensing, biolabeling, photonics, and nanomedicine.

  8. ROS-mediated apoptotic cell death in prostate cancer LNCaP cells induced by biosurfactant stabilized CdS quantum dots.

    Science.gov (United States)

    Singh, Braj R; Singh, Brahma N; Khan, W; Singh, H B; Naqvi, A H

    2012-08-01

    Cadmium sulfide (CdS) quantum dots (QDs) have raised great attention because of their superior optical properties and wide utilization in biological and biomedical studies. However, little is known about the cell death mechanisms of CdS QDs in human cancer cells. This study was designed to investigate the possible mechanisms of apoptosis induced by biosurfactant stabilized CdS QDs (denoted as "bsCdS QDs") in human prostate cancer LNCaP cells. It was also noteworthy that apoptosis correlated with reactive oxygen species (ROS) production, mitochondrial damage, oxidative stress and chromatin condensation in a dose- and time-dependent manner. Results also showed involvement of caspases, Bcl-2 family proteins, heat shock protein 70, and a cell-cycle checkpoint protein p53 in apoptosis induction by bsCdS QDs in LNCaP cells. Moreover, pro-apoptotic protein Bax was upregulated and the anti-apoptotic proteins, survivin and NF-κB were downregulated in bsCdS QDs exposed cells. Protection of N-acetyl cysteine (NAC) against ROS clearly suggested the implication of ROS in hyper-activation of apoptosis and cell death. It is encouraging to conclude that biologically stabilized CdS QDs bear the potential of its applications in biomedicine, such as tumor therapy specifically by inducing caspase-dependent apoptotic cell death of human prostate cancer LNCaP cells. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  9. Cadmium induced radioadaptive response via an ATM-independent H2S/cystathionine γ-lyase modulation

    International Nuclear Information System (INIS)

    Pan Yan; Yuan Dexiao; Zhang Jianghong; Shao Chunlin

    2011-01-01

    The combined exposure to environmental toxicants such as heavy metals and radiation is an important research area in health protection. Here we explored cadmium induced radioadaptive response (RAR) and investigated the role of hydrogen sulfide (H 2 S) and ATM kinase in this response. Our data showed that the cadmium ions with a sub-lethal concentration could induce RAR in Chang liver cells towards subsequent γ-irradiation and this response could be abrogated by DL-propargylglycine (PPG), the endogenous H 2 S synthetase inhibitor of cystathionine γ-lyase (CSE), but not by aminooxyacetic acid (AOAA), the inhibitor of cystathionine β-synthase (CBS). Moreover, the pretreatment of cells with NaHS also stimulated cellular adaptive response to radiation. Both cadmium treatment and irradiation up-regulated the expression of CSE protein in a time-dependent manner but had no influence on the expression of CBS protein. In the primed cells, the time course of CBS expression showed no significant difference with the cells treated with 2Gy irradiation alone, however, the CSE expression was easier to reach the maximum level, indicating a more efficient H 2 S production by CSE. Moreover, the cadmium-induced RAR was totally suppressed by KU-55933, a specific ATM inhibitor that did not change the CSE expression after radiation. However, exogenous H 2 S decreased the phosphorylation level of radiation-induced ATM. In conclusion, the present results demonstrate firstly that H 2 S is involved in the cadmium induced cross-adaptive response to challenging radiation. CSE, rather than CBS, may mainly responsible for the H 2 S production during this RAR which may also be mediated by ATM pathway. However, the activation of CSE is independent of ATM but could negatively regulate the phosphorylation of ATM.

  10. Nonlinear Dynamics In Quantum Physics -- Quantum Chaos and Quantum Instantons

    OpenAIRE

    Kröger, H.

    2003-01-01

    We discuss the recently proposed quantum action - its interpretation, its motivation, its mathematical properties and its use in physics: quantum mechanical tunneling, quantum instantons and quantum chaos.

  11. Cadmium Exposure is Associated with the Prevalence of Dyslipidemia

    Directory of Open Access Journals (Sweden)

    Zhou Zhou

    2016-11-01

    Full Text Available Background: Cadmium is a widespread environmental and occupational pollutant that accumulates in human body with a biological half-life exceeding 10 years. Cadmium exposure has been demonstrated to increase rates of cardiovascular diseases. Whether occupational cadmium exposure is associated with the increase in the prevalence of dyslipidemia and hence contributes to the risk of cardiovascular diseases is still equivocal. To test the hypothesis that exposure to cadmium is related to the prevalence of dyslipidemia, we examined the associations between blood cadmium concentration and the prevalence of dyslipidemia in workers occupationally exposed to cadmium in China. Methods: A cross-sectional survey on demographic data, blood cadmium level and lipid profile in cadmium exposed workers from seven cadmium smelting factories in central and southwestern China was conducted. We measured blood cadmium concentration and lipid components of 1489 cadmium exposed workers. The prevalence of dyslipidemia was compared across blood cadmium quartiles. Associations between the blood cadmium concentrations and the prevalence of dyslipidemia were assessed using confounder adjusted linear and logistic regressions. Results: The blood cadmium concentration was 3.61±0.84µg/L ( mean ±SD. The prevalence of dyslipidemia in this occupational population was 66.3%. Mean blood cadmium concentration of workers with dyslipedemia was significantly higher than that of workers without dyslipidemia (p Conclusion: Elevated blood cadmium concentration is associated with prevalence of dyslipidemia. Cadmium exposure could alter lipid metabolism in humans. It is imperative to control cadmium exposure of occupational population in cadmium related industries and reduce adverse health effects.

  12. Reduced cytotoxicity of insulin-immobilized CdS quantum dots using PEG as a spacer

    Directory of Open Access Journals (Sweden)

    Choi Moon-Jeong

    2011-01-01

    Full Text Available Abstract Cytotoxicity is a severe problem for cadmium sulfide nanoparticles (CSNPs in biological systems. In this study, mercaptoacetic acid-coated CSNPs, typical semiconductor Q-dots, were synthesized in aqueous medium by the arrested precipitation method. Then, amino-terminated polyethylene glycol (PEG was conjugated to the surface of CSNPs (PCSNPs in order to introduce amino groups to the surface. Finally, insulin was immobilized on the surface of PCSNPs (ICSNPs to reduce cytotoxicity as well as to enhance cell compatibility. The presence of insulin on the surface of ICSNPs was confirmed by observing infrared absorptions of amide I and II. The mean diameter of ICSNPs as determined by dynamic light scattering was about 38 nm. Human fibroblasts were cultured in the absence and presence of cadmium sulfide nanoparticles to evaluate cytotoxicity and cell compatibility. The results showed that the cytotoxicity of insulin-immobilized cadmium sulfide nanoparticles was significantly suppressed by usage of PEG as a spacer. In addition, cell proliferation was highly facilitated by the addition of ICSNPs. The ICSNPs used in this study will be potentials to be used in bio-imaging applications.

  13. Carbon steel protection in G.S. (Girlder sulfide) plants. Iron sulfide scales formation conditions. Pt. 1

    International Nuclear Information System (INIS)

    Bruzzoni, P.; Burkart, A.L.; Garavaglia, R.N.

    1981-11-01

    An ASTM A 516 degree 60 carbon steel superficial protection technique submitted to a hydrogen-water sulfide corrosive medium at 2 MPa of pressure and 40-125 deg C forming on itself an iron sulfide layer was tested. Studies on pH influence, temperature, passivating mean characteristics and exposure time as well as the mechanical resistance of sulfide layers to erosion are included. (Author) [es

  14. 76 FR 64022 - Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting

    Science.gov (United States)

    2011-10-17

    ... Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting AGENCY: Environmental Protection Agency (EPA). ACTION: Lifting of Administrative Stay for Hydrogen Sulfide. SUMMARY: EPA is announcing... (EPCRA) section 313 toxic chemical release reporting requirements for hydrogen sulfide (Chemical...

  15. Rising environmental cadmium levels in developing countries ...

    African Journals Online (AJOL)

    olayemitoyin

    Cadmium (Cd) is a non essential heavy metal belonging to group ... Cd from a contaminated environment leads to various pathological ..... interact with genes that are involved in human ..... Tolonen, M. (1990) Vitamins and minerals in Health.

  16. Large silver-cadmium technology program

    Science.gov (United States)

    Charlip, S.; Lerner, S.

    1971-01-01

    The effects of varying cell design on operation factors on the electrochemical performance of sealed, silver-cadmium cells were determined. A factorial experiment was conducted for all test cells constructed with organic separators. Three operating factors were evaluated: temperature, depth of discharge, and charge rate. The six construction factors considered were separator, absorber, electrolyte quantity, cadmium electrode type, cadmium-to-silver ratio, and auxiliary electrode. Test cells of 4 ampere-hour capacity were fabricated and cycled. The best performing cells, on a 94 minute orbit, at 40% depth of discharge, were those containing silver-treated fibrous sausage casings as the separator, and Teflon-ated, pressed cadmium electrodes. Cycling data of cells with inorganic separators (Astroset) are given. Best performance was shown by cells with nonwoven nylon absorbers. Rigid inorganic separators provided the best barrier to silver migration.

  17. Detection of cadmium sulphide nanoparticles by using screen-printed electrodes and a handheld device

    International Nuclear Information System (INIS)

    Merkoci, Arben; Marcolino-Junior, Luiz Humberto; MarIn, Sergio; Fatibello-Filho, Orlando; Alegret, Salvador

    2007-01-01

    A simple method based on screen-printed electrodes and a handheld potentiostatic device is reported for the detection of water soluble CdS quantum dots modified with glutathione. The detection method is based on the stripping of electrochemically reduced cadmium at pH 7.0 by using square wave voltammetry. Various parameters that affect the sensitivity of the method are optimized. QD suspension volumes of 20 μl and a number of around 2 x 10 11 CdS quantum dots have been able to be detected. The proposed method should be of special interest for bioanalytical assays, where CdS quantum dots can be used as electrochemical tracers

  18. Integrated process using non-stoichiometric sulfides or oxides of potassium for making less active metals and hydrocarbons

    International Nuclear Information System (INIS)

    Swanson, R.

    1984-01-01

    Disclosed is a combinative integrated chemical process using inorganic reactants and yielding, if desired, organic products. The process involves first the production of elemental potassium by the thermal or thermal-reduced pressure decomposition of potassium oxide or potassium sulfide and distillation of the potassium. This elemental potassium is then used to reduce ores or ore concentrates of copper, zinc, lead, magnesium, cadmium, iron, arsenic, antimony or silver to yield one or more of these less active metals in elemental form. Process potassium can also be used to produce hydrogen by reaction with water or potassium hydroxide. This hydrogen is reacted with potassium to produce potassium hydride. Heating the latter with carbon produces potassium acetylide which forms acetylene when treated with water. Acetylene is hydrogenated to ethene or ethane with process hydrogen. Using Wurtz-Fittig reaction conditions, the ethane can be upgraded to a mixture of hydrocarbons boiling in the fuel range

  19. Cadmium poisoning. Knowledge of the risk

    International Nuclear Information System (INIS)

    Peltier, A.; Demange, M.; Carton, M.B.

    1979-01-01

    This data sheet provides an up-to-date summary of information on cadmium poisoning. The following points are examined: - the problem of increasing pollution of soil, water and the food chain; - physical and chemical properties, manufacture, industrial applications; - the toxic action of cadmium and its derivatives; - methods and apparatus for taking and analysis samples from the atmosphere and from body fluids; - existing French regulations; - technical control and medical surveillance [fr

  20. Synthetic Developments of Nontoxic Quantum Dots.

    Science.gov (United States)

    Das, Adita; Snee, Preston T

    2016-03-03

    Semiconductor nanocrystals, or quantum dots (QDs), are candidates for biological sensing, photovoltaics, and catalysis due to their unique photophysical properties. The most studied QDs are composed of heavy metals like cadmium and lead. However, this engenders concerns over heavy metal toxicity. To address this issue, numerous studies have explored the development of nontoxic (or more accurately less toxic) quantum dots. In this Review, we select three major classes of nontoxic quantum dots composed of carbon, silicon and Group I-III-VI elements and discuss the myriad of synthetic strategies and surface modification methods to synthesize quantum dots composed of these material systems. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Iron sulfide crystal growth: a literature review

    International Nuclear Information System (INIS)

    Dewar, E.J.

    1977-04-01

    Iron pyrite (FeS 2 ) is often found on trays and in heat exchangers in Girdler-Sulfide (G.S.) plants used to extract D 2 O from fresh water. A critical review of the literature was made to find: (i) what is known about FeS 2 crystal growth; (ii) which techniques could be used to study FeS 2 crystal growth experimentally; (iii) potential chemical additives that could be used in trace amounts to poison FeS 2 crystals and reduce their growth rate in G.S. plants. (author)

  2. Sulfide geochronlogy along the Southwest Indian Ridge

    Science.gov (United States)

    Yang, W.; Tao, C.; Li, H.; Liang, J.; Liao, S.

    2017-12-01

    Dragon Flag and Duanqiao hydrothermal field is located between the Indomed and Gallieni fracture zones in the ultraslow-spreading Southwest Indian Ridge (SWIR). Ten subsamples from active and inactive vents of Dragon Flag hydrothermal field and twenty-eight subsamples from Duanqiao hydrothermal field were dated using the 230Th/238U method. Four main episodes of hydrothermal activity of Duanqiao were determined according to the restricted results: 68.9-84.3, 43.9-48.4, 25.3-34.8, and 0.7-17.3 kyrs. Hydrothermal activity of Duanqiao probably started about 84.3 (±0.5) kyrs ago and ceased about 0.737 (±0.023) kyrs ago. And sulfide samples from the nearby Dragon Flag filed at the same time and the results show that the ages of most sulfides from Dragon Flag field range from 1.496(±0.176) to 5.416 (±0.116) kyrs with the oldest age estimated at 15.997 (±0.155) kyrs Münch et al. (2001) reconstructed the evolution history of Mt. Jourdanne hydrothermal field. The age dating results indicate activity in two episodes, at 70-40 and 27-13 kyrs. The hydrothermal activity in Dragon Flag field is much more recent than that of Duanqiao or Mt. Jourdanne fields. The massive sulfides are younger than the sulfides from other hydrothermal fields such as Rainbow, Sonne and Ashadze-2. All these results suggest that hydrothermal activity of Dragon Flag field is much more recent than that of Duanqiao or Mt. Jourdanne fields. Mt. Jourdanne is situated on an axial volcanic ridge which has both volcanic and tectonic activity. This is necessary to develop the heat source and pathways for the fluid convection, which enables the hydrothermal circulation. Hydrothermal activity in Dragon Flag Field is located next to the detachment fault termination. The detachment fault system provides a pathway for hydrothermal convection. Such style of heat source can contribute to continuous hydrothermal activity for over 1000 years. Duanqiao field is located near the central volcano and there is a hot

  3. Quantum mechanics

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    The book is on quantum mechanics. The emphasis is on the basic concepts and the methodology. The chapters include: Breakdown of classical concepts; Quantum mechanical concepts; Basic postulates of quantum mechanics; solution of problems in quantum mechanics; Simple harmonic oscillator; and Angular Momentum

  4. Quantum matter

    International Nuclear Information System (INIS)

    Buechler, Hans Peter; Calcarco, Tommaso; Dressel, Martin

    2008-01-01

    The following topics are dealt with: Artificial atoms and molecules, tailored from solids, fractional flux quanta, molecular magnets, controlled interaction in quantum gases, the theory of quantum correlations in mott matter, cold gases, and mesoscopic systems, Bose-Einstein condensates on the chip, on the route to the quantum computer, a quantum computer in diamond. (HSI)

  5. Quantum fluctuations

    International Nuclear Information System (INIS)

    Reynaud, S.; Giacobino, S.; Zinn-Justin, J.

    1997-01-01

    This course is dedicated to present in a pedagogical manner the recent developments in peculiar fields concerned by quantum fluctuations: quantum noise in optics, light propagation through dielectric media, sub-Poissonian light generated by lasers and masers, quantum non-demolition measurements, quantum electrodynamics applied to cavities and electrical circuits involving superconducting tunnel junctions. (A.C.)

  6. Biological monitoring results for cadmium exposed workers.

    Science.gov (United States)

    McDiarmid, M A; Freeman, C S; Grossman, E A; Martonik, J

    1996-11-01

    As part of a settlement agreement with the Occupational Safety and Health Administration (OSHA) involving exposure to cadmium (Cd), a battery production facility provided medical surveillance data to OSHA for review. Measurements of cadmium in blood, cadmium in urine, and beta 2-microglobulin in urine were obtained for more than 100 workers over an 18-month period. Some airborne Cd exposure data were also made available. Two subpopulations of this cohort were of primary interest in evaluating compliance with the medical surveillance provisions of the Cadmium Standard. These were a group of 16 workers medically removed from cadmium exposure due to elevations in some biological parameter, and a group of platemakers. Platemaking had presented a particularly high exposure opportunity and had recently undergone engineering interventions to minimize exposure. The effect on three biological monitoring parameters of medical removal protection in the first group and engineering controls in platemakers is reported. Results reveal that both medical removal from cadmium exposures and exposure abatement through the use of engineering and work practice controls generally result in declines in biological monitoring parameters of exposed workers. Implications for the success of interventions are discussed.

  7. Cadmium affects retinogenesis during zebrafish embryonic development

    International Nuclear Information System (INIS)

    Hen Chow, Elly Suk; Yu Hui, Michelle Nga; Cheng, Chi Wa; Cheng, Shuk Han

    2009-01-01

    Ocular malformations are commonly observed in embryos of aquatic species after exposure to toxicants. Using zebrafish embryos as the model organism, we showed that cadmium exposure from sphere stage (4 hpf) to end of segmentation stage (24 hpf) induced microphthalmia in cadmium-treated embryos. Embryos with eye defects were then assessed for visual abilities. Cadmium-exposed embryos were behaviorally blind, showing hyperpigmentation and loss of camouflage response to light. We investigated the cellular basis of the formation of the small eyes phenotype and the induction of blindness by studying retina development and retinotectal projections. Retinal progenitors were found in cadmium-treated embryos albeit in smaller numbers. The number of retinal ganglion cells (RGC), the first class of retinal cells to differentiate during retinogenesis, was reduced, while photoreceptor cells, the last batch of retinal neurons to differentiate, were absent. Cadmium also affected the propagation of neurons in neurogenic waves. The neurons remained in the ventronasal area and failed to spread across the retina. Drastically reduced RGC axons and disrupted optic stalk showed that the optic nerves did not extend from the retina beyond the chiasm into the tectum. Our data suggested that impairment in neuronal differentiation of the retina, disruption in RGC axon formation and absence of cone photoreceptors were the causes of microphthalmia and visual impairment in cadmium-treated embryos

  8. Human health effects of exposure to cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Hallenbeck, W.H.

    1986-01-01

    The health effects of human exposure to cadmium are discussed with emphases on intake, absorption, body burden, and excretion; osteomalacia in Japan; hypertension; and proteinuria, emphysema, osteomalacia, and cancer in workers. Elevated blood pressure has not been observed as a result of excessive exposures to cadmium in Japan or the workplace. Renal tubular dysfunction and consequent proteinuria is generally accepted as the main effect following long-term, low-level exposure to cadmium. Studies of workers show that proteinuria may develop after the first year of exposure or many years after the last exposure. Proteinuria and deterioration of renal function may continue even after cessation of exposure. The immediate health significance of low-level proteinuria is still under debate. However, there is evidence that long-term renal tubular dysfunction may lead to abnormalities of calcium metabolism and osteomalacia. The few autopsy and cross-sectional studies of workers do not permit conclusions to be drawn regarding the relationship between cadmium exposure and emphysema. Retrospective and historical-prospective studies are needed to settle this important question. No conclusive evidence has been published regarding cadmium-induced cancer in humans. However, there is sufficient evidence to regard cadmium as a suspect renal and prostate carcinogen. Because of equivocal results and the absence of dose-response relationships, the studies reviewed should be used with caution in making regulatory decisions and low-dose risk assessments. 62 references.

  9. Human health effects of exposure to cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Hallenbeck, W.H.

    1984-02-15

    The health effects of human exposure to cadmium are discussed with emphasis on intake, absorption, body burden, and excretion; osteomalacia in Japan; hypertension; and proteinuria, emphysema, osteomalacia, and cancer in workers. Elevated blood pressure has not been observed as a result of excessive exposures to cadmium in Japan or the workplace. Renal tubular dysfunction and consequent proteinuria is generally accepted as the main effect following long-term, low-level exposure to cadmium. Studies of workers show that proteinuria may develop after the first year of exposure or many years after the last exposure. Proteinuria and deterioration of renal function may continue even after cessation of exposure. The immediate health significance of low-level proteinuria is still under debate. However, there is evidence that long-term renal tubular dysfunction may lead to abnormalities of calcium metabolism and osteomalacia. The few autopsy and cross-sectional studies of workers do not permit conclusions to be drawn regarding the relationship between cadmium exposure and emphysema. Retrospective and historical-prospective studies are needed to settle this important question. No conclusive evidence has been published regarding cadmium-induced cancer in humans. However, there is sufficient evidence to regard cadmium as a suspect renal and prostate carcinogen. Because of equivocal results and the absence of dose-response relationships, the studies reviewed should be used with caution in making regulatory decisions and low-dose risk assessments.

  10. Quantum radar

    CERN Document Server

    Lanzagorta, Marco

    2011-01-01

    This book offers a concise review of quantum radar theory. Our approach is pedagogical, making emphasis on the physics behind the operation of a hypothetical quantum radar. We concentrate our discussion on the two major models proposed to date: interferometric quantum radar and quantum illumination. In addition, this book offers some new results, including an analytical study of quantum interferometry in the X-band radar region with a variety of atmospheric conditions, a derivation of a quantum radar equation, and a discussion of quantum radar jamming.This book assumes the reader is familiar w

  11. Annealing of wet treated Cu(In,Ga)(S,Se){sub 2} solar cells with an indium sulfide buffer

    Energy Technology Data Exchange (ETDEWEB)

    Hönes, C., E-mail: christian.hoenes.001@student.uni.lu; Siebentritt, S., E-mail: susanne.siebentritt@uni.lu

    2015-05-01

    Compound evaporated indium sulfide is one commonly utilized cadmium free buffer layer for Cu(In,Ga)(S,Se){sub 2} solar cells. However, cells with such a buffer layer usually need a post-deposition annealing step to reach the maximum short circuit current, fill factor and open circuit voltage. In this work wet chemical treatments, partly containing cadmium ions, are applied to commercially available absorber material prior to indium sulfide evaporation in order to enhance the initial solar cell parameters. Cells built on treated absorbers show maximum open circuit voltage directly after window layer deposition and a drop in open circuit voltage is observed upon annealing. All samples, however, show an increased collection length and higher fill factor after annealing. A one diode model fit to the current-voltage curves gives ideality factors of 1.7 before annealing which are reduced to values around 1.5 after annealing. Supporting calculations show that the changes upon annealing can be explained within a model including a highly p-doped absorber surface layer. During annealing the acceptor density at the absorber surface might be reduced thus leading to a larger space charge region and thereby increasing the collection length and fill factor while reducing the open circuit voltage. - Highlights: • Wet treatments raise initial voltage of In{sub 2}S{sub 3} buffered Cu(In,Ga)(S,Se){sub 2} solar cells. • Collection length increase after annealing of treated cells is observed. • Voltage decay is explained within a model including a highly p-doped surface layer. • Supporting simulations are in good agreement with the experiments.

  12. Microbial selenium sulfide reduction for selenium recovery from wastewater

    NARCIS (Netherlands)

    Hageman, S.P.W.; Weijden, van der R.D.; Stams, A.J.M.; Cappellen, van P.; Buisman, C.J.N.

    2017-01-01

    Microbial reduction of selenium sulfide (SeS2) is a key step in a new treatment process to recover selenium from selenate and selenite streams. In this process, selenate is first reduced to selenite, and subsequently selenite is reduced by sulfide and precipitates from the solution as SeS2. The

  13. Recent findings on sinks for sulfide in gravity sewer networks

    DEFF Research Database (Denmark)

    Nielsen, Asbjørn Haaning; Hvitved-Jacobsen, Thorkild; Vollertsen, Jes

    2006-01-01

    summarizes this newly obtained knowledge and emphasizes important implications of the findings. Model simulations of the in-sewer processes important for the sulfur cycle showed that sulfide oxidation in the wetted biofilm is typically the most important sink for dissolved sulfide in gravity sewers. However...

  14. Technetium behavior in sulfide and ferrous iron solutions

    International Nuclear Information System (INIS)

    Lee, S.Y.; Bondietti, E.A.

    1982-01-01

    Pertechnetate oxyanion ( 99 TcO 4- ), a potentially mobile species in leachate from a breached radioactive waste repository, was removed from a brine solution by precipitation with sulfide, iron, and ferrous sulfide at environmental pH's. Maghemite (ν-Fe 2 O 3 ) and geothite (α-FeOOH) were the dominant minerals in the precipitate obtained from the TcO 4- -ferrous iron reaction. The observation of small particle size and poor crystallinity of the minerals formed in the presence of Tc suggested that the Tc was incorporated into the mineral structure after reduction to a lower valence state. Amorphous ferrous sulfide, an initial phase precipitating in the TcO 4- -ferrous iron-sulfide reaction, was transformed to goethite and hematite (α-Fe 2 O 3 ) on aging. The black precipitate obtained from the TcO 4- -sulfide reaction was poorly crystallized technetium sulfide (Tc 2 S 7 ) which was insoluble in both acid and alkaline solution in the absence of strong oxidents. The results suggested that ferrous- and/or sulfide-bearing groundwaters and minerals in host rocks or backfill barriers could reduce the mobility of Tc through the formation of less-soluble Tc-bearing iron and/or sulfide minerals

  15. Sulfidation of carbon-supported iron oxide catalysts

    NARCIS (Netherlands)

    Ramselaar, W.L.T.M.; Hadders, R.H.; Gerkema, E.; Beer, de V.H.J.; Oers, van E.M.; Kraan, van der A.M.

    1989-01-01

    The sulfidation of carbon-supported iron oxide catalysts was studied by means of in-situ Mössbauer spectroscopy at temperatures down to 4.2 K. The catalysts were dried in two different ways and then sulfided in a flow of 10% H2S in H2 at temperatures between 293 and 773 K. Thiophene

  16. Quantum information

    International Nuclear Information System (INIS)

    Kilin, Sergei Ya

    1999-01-01

    A new research direction known as quantum information is a multidisciplinary subject which involves quantum mechanics, optics, information theory, programming, discrete mathematics, laser physics and spectroscopy, and depends heavily on contributions from such areas as quantum computing, quantum teleportation and quantum cryptography, decoherence studies, and single-molecule and impurity spectroscopy. Some new results achieved in this rapidly growing field are discussed. (reviews of topical problems)

  17. Quantum information

    Energy Technology Data Exchange (ETDEWEB)

    Kilin, Sergei Ya [B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, Minsk (Belarus)

    1999-05-31

    A new research direction known as quantum information is a multidisciplinary subject which involves quantum mechanics, optics, information theory, programming, discrete mathematics, laser physics and spectroscopy, and depends heavily on contributions from such areas as quantum computing, quantum teleportation and quantum cryptography, decoherence studies, and single-molecule and impurity spectroscopy. Some new results achieved in this rapidly growing field are discussed. (reviews of topical problems)

  18. Quantum ontologies

    International Nuclear Information System (INIS)

    Stapp, H.P.

    1988-12-01

    Quantum ontologies are conceptions of the constitution of the universe that are compatible with quantum theory. The ontological orientation is contrasted to the pragmatic orientation of science, and reasons are given for considering quantum ontologies both within science, and in broader contexts. The principal quantum ontologies are described and evaluated. Invited paper at conference: Bell's Theorem, Quantum Theory, and Conceptions of the Universe, George Mason University, October 20-21, 1988. 16 refs

  19. Luminescence properties of copper(I), zinc(II) and cadmium(II) coordination compounds with picoline ligands

    Energy Technology Data Exchange (ETDEWEB)

    Małecki, Jan Grzegorz, E-mail: gmalecki@us.edu.pl; Maroń, Anna

    2017-06-15

    Mononuclear coordination compounds of copper(I) – [Cu(PPh{sub 3}){sub 2}(picoline)(NO{sub 3})], zinc(II) – [ZnCl{sub 2}(picoline){sub 2}] (picoline=3– and 4–methylpyridine) and polymeric cadmium(II) – [CdCl{sub 2}(β-picoline){sub 2}]{sub n} were prepared and their luminescence properties in solid state and acetonitrile solutions were determined. Single crystal X-ray crystallography revealed distorted tetrahedral geometry around the central ions of the compounds. The compounds exhibit green photoluminescence in solid state and in acetonitrile solutions. The emission of copper(I) compounds originated from metal-to-ligand charge transfer state combined with nitrato-to-picoline charge transfer state i.e. ({sup 1}(M+X)LCT). The presence of nitrato ligand in the coordination sphere of copper(I) compounds quenches the emission. Luminescence of zinc(II) and cadmium(II) compounds results from chloride-to-picoline charge transfer state and the quantum efficiency in the case of the polymeric Cd(II) compound reaches 39%. The photoluminescence quantum yields of the mononuclear zinc(II) compounds vary from 10 to 16% depending on the conditions (solid state, solution). - Graphical abstract: Coordination compounds of copper(I), zinc(II) and polymeric cadmium(II) with picoline ligands were prepared and their luminescence properties in solid state and acetonitrile solutions were determined. The compounds exhibit green photoluminescence in solid state and in acetonitrile solutions. Emission of copper(I) compounds originated from {sup 1}(M+X)LCT state. Luminescence of zinc(II) and cadmium(II) compounds results from chloride-to-picoline charge transfer state and the quantum efficiency in the case of the polymeric Cd(II) compound reaches 39%. The photoluminescence quantum yields of the mononuclear zinc(II) compounds vary from 10 to 16% depending on the conditions (solid state, solution).

  20. Influence of Water Salinity on Air Purification from Hydrogen Sulfide

    Directory of Open Access Journals (Sweden)

    Leybovych L.I.

    2015-12-01

    Full Text Available Mathematical modeling of «sliding» water drop motion in the air flow was performed in software package FlowVision. The result of mathematical modeling of water motion in a droplet with diameter 100 microns at the «sliding» velocity of 15 m/s is shown. It is established that hydrogen sulfide oxidation occurs at the surface of phases contact. The schematic diagram of the experimental setup for studying air purification from hydrogen sulfide is shown. The results of the experimental research of hydrogen sulfide oxidation by tap and distilled water are presented. The dependence determining the share of hydrogen sulfide oxidized at the surface of phases contact from the dimensionless initial concentration of hydrogen sulfide in the air has been obtained.

  1. Sulindac Sulfide, but Not Sulindac Sulfone, Inhibits Colorectal Cancer Growth

    Directory of Open Access Journals (Sweden)

    Christopher S. Williams

    1999-06-01

    Full Text Available Sulindac sulfide, a metabolite of the nonsteroidal antiinflammatory drug (NSAID sulindac sulfoxide, is effective at reducing tumor burden in both familial adenomatous polyposis patients and in animals with colorectal cancer. Another sulindac sulfoxide metabolite, sulindac sulfone, has been reported to have antitumor properties without inhibiting cyclooxygenase activity. Here we report the effect of sulindac sulfone treatment on the growth of colorectal carcinoma cells. We observed that sulindac sulfide or sulfone treatment of HCA-7 cells led to inhibition of prostaglandin E2 production. Both sulindac sulfide and sulfone inhibited HCA-7 and HCT-116 cell growth in vitro. Sulindac sulfone had no effect on the growth of either HCA-7 or HCT-116 xenografts, whereas the sulfide derivative inhibited HCA-7 growth in vivo. Both sulindac sulfide and sulfone inhibited colon carcinoma cell growth and prostaglandin production in vitro, but sulindac sulfone had no effect on the growth of colon cancer cell xenografts in nude mice.

  2. Oxidation and Precipitation of Sulfide in Sewer Networks

    DEFF Research Database (Denmark)

    Nielsen, A. H.

    risks and corrosion of concrete and metals. Most of the problems relate to the buildup of hydrogen sulfide in the atmosphere of sewer networks. In this respect, the processes of the sulfur cycle are of fundamental importance in ultimately determining the extent of such problems. This study focused...... calibrated and validated against field data. In the extension to the WATS model, sulfur transformations were described by six processes: 1. Sulfide production taking place in the biofilm and sediments covering the permanently wetted sewer walls; 2. Biological sulfide oxidation in the permanently wetted...... to the sewer atmosphere, potentially resulting in concrete corrosion. The extended WATS model represents a major improvement over previously developed models for prediction of sulfide buildup in sewer networks. Compared to such models, the major processes governing sulfide buildup in sewer networks...

  3. Kinetic Spectrophotometric Determination of Trace Amounts of Sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Barzegar, Mohsen [Tarbiat Modarres University, Tehran (Iran, Islamic Republic of); Jabbari, Ali [K. N. Toosi University, Tehran (Iran, Islamic Republic of); Esmaeili, Majid [Razi University, Kermanshah (Iran, Islamic Republic of)

    2003-09-15

    A method for the determination of trace amount of sulfide based on the addition reaction of sulfide with methyl green at pH 7.5 and 25 .deg. C is described. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of the dyestuff at 637 nm by the initial rate and fixed time method. The calibration graph is linear in the range 30-1200 ppb. The theoretical limit of detection was 0.014 ppm. Seven replicate analysis of a sample solution containing 0.70 ppm sulfide gave a relative standard deviation of 1.5%. The interfering effects of various ions on sulfide determination have been reported and procedures for removal of interference have been described. The proposed method was applied successfully to the determination of sulfide in tap and wastewater samples.

  4. Kinetic Spectrophotometric Determination of Trace Amounts of Sulfide

    International Nuclear Information System (INIS)

    Barzegar, Mohsen; Jabbari, Ali; Esmaeili, Majid

    2003-01-01

    A method for the determination of trace amount of sulfide based on the addition reaction of sulfide with methyl green at pH 7.5 and 25 .deg. C is described. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of the dyestuff at 637 nm by the initial rate and fixed time method. The calibration graph is linear in the range 30-1200 ppb. The theoretical limit of detection was 0.014 ppm. Seven replicate analysis of a sample solution containing 0.70 ppm sulfide gave a relative standard deviation of 1.5%. The interfering effects of various ions on sulfide determination have been reported and procedures for removal of interference have been described. The proposed method was applied successfully to the determination of sulfide in tap and wastewater samples

  5. Quantum Computer Games: Quantum Minesweeper

    Science.gov (United States)

    Gordon, Michal; Gordon, Goren

    2010-01-01

    The computer game of quantum minesweeper is introduced as a quantum extension of the well-known classical minesweeper. Its main objective is to teach the unique concepts of quantum mechanics in a fun way. Quantum minesweeper demonstrates the effects of superposition, entanglement and their non-local characteristics. While in the classical…

  6. Reviews of the environmental effects of pollutants: IV. Cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Hammons, A.S.; Huff, J.E.; Braunstein, H.M.; Drury, J.S.; Shriner, C.R.; Lewis, E.B.; Whitfield, B.L.; Towill, L.E.

    1978-06-01

    This report is a comprehensive, multidisciplinary review of the health and environmental effects of cadmium and specific cadmium derivatives. More than 500 references are cited. The cadmium body burden in animals and humans results mainly from the diet. In the United States, the normal intake of cadmium for adult humans is estimated at about 50 ..mu..g per day. Tobacco smoke is a significant additional source of cadmium exposure. The kidneys and liver together contain about 50% of the total cadmium body burden. Acute cadmium poisoning is primarily an occupational problem, generally from inhalation of cadmium fumes or dusts. In the general population, incidents of acute poisoning by inhaled or ingested cadmium or its compounds are relatively rare. The kidney is the primary target organ for toxicity from prolonged low-level exposure to cadmium. No causal relationship has been established between cadmium exposure and human cancer, although a possible link between cadmium and prostate cancer has been indicated. Cadmium has been shown to be teratogenic in rats, hamsters, and mice, but no such effects have been proven in humans. Cadmium has been reported to increase the frequency of chromosomal aberrations in cultured Chinese hamster ovary cells and in human peripheral leukocytes. The major concern about environmental cadmium is the potential effects on the general population. There is no substantial evidence of hazard from current levels of cadmium in air, water, or food. However, because cadmium is a cumulative poison and because present intake provides a relatively small safety margin, there are adequate reasons for concern over possible future increases in background levels.

  7. Reviews of the environmental effects of pollutants: IV. Cadmium

    International Nuclear Information System (INIS)

    Hammons, A.S.; Huff, J.E.; Braunstein, H.M.; Drury, J.S.; Shriner, C.R.; Lewis, E.B.; Whitfield, B.L.; Towill, L.E.

    1978-06-01

    This report is a comprehensive, multidisciplinary review of the health and environmental effects of cadmium and specific cadmium derivatives. More than 500 references are cited. The cadmium body burden in animals and humans results mainly from the diet. In the United States, the normal intake of cadmium for adult humans is estimated at about 50 μg per day. Tobacco smoke is a significant additional source of cadmium exposure. The kidneys and liver together contain about 50% of the total cadmium body burden. Acute cadmium poisoning is primarily an occupational problem, generally from inhalation of cadmium fumes or dusts. In the general population, incidents of acute poisoning by inhaled or ingested cadmium or its compounds are relatively rare. The kidney is the primary target organ for toxicity from prolonged low-level exposure to cadmium. No causal relationship has been established between cadmium exposure and human cancer, although a possible link between cadmium and prostate cancer has been indicated. Cadmium has been shown to be teratogenic in rats, hamsters, and mice, but no such effects have been proven in humans. Cadmium has been reported to increase the frequency of chromosomal aberrations in cultured Chinese hamster ovary cells and in human peripheral leukocytes. The major concern about environmental cadmium is the potential effects on the general population. There is no substantial evidence of hazard from current levels of cadmium in air, water, or food. However, because cadmium is a cumulative poison and because present intake provides a relatively small safety margin, there are adequate reasons for concern over possible future increases in background levels

  8. Cadmium removal by Lemna minor and Spirodela polyrhiza.

    Science.gov (United States)

    Chaudhuri, Devaleena; Majumder, Arunabha; Misra, Amal K; Bandyopadhyay, Kaushik

    2014-01-01

    The present study investigates the ability of two genus of duckweed (Lemna minor and Spirodela polyrhiza) to phytoremediate cadmium from aqueous solution. Duckweed was exposed to six different cadmium concentrations, such as, 0.5,1.0,1.5, 2.0, 2.5, and 3.0 mg/L and the experiment was continued for 22 days. Water samples were collected periodically for estimation of residual cadmium content in aqueous solution. At the end of treatment period plant samples were collected and accumulated cadmium content was measured. Cadmium toxicity was observed through relative growth factor and changes in chlorophyll content Experimental results showed that Lemna minor and Spirodela polyrhiza were capable of removing 42-78% and 52-75% cadmium from media depending upon initial cadmium concentrations. Cadmium was removed following pseudo second order kinetic model Maximum cadmium accumulation in Lemna minor was 4734.56 mg/kg at 2 mg/L initial cadmium concentration and 7711.00 mg/kg in Spirodela polyrhiza at 3 mg/L initial cadmium concentration at the end of treatment period. Conversely in both cases maximum bioconcentration factor obtained at lowest initial cadmium concentrations, i.e., 0.5 mg/L, were 3295.61 and 4752.00 for Lemna minor and Spirodela polyrhiza respectively. The present study revealed that both Lemna minor and Spirodela polyrhiza was potential cadmium accumulator.

  9. Anoxic sulfide biooxidation using nitrite as electron acceptor

    International Nuclear Information System (INIS)

    Mahmood, Qaisar; Zheng Ping; Cai Jing; Wu Donglei; Hu, Baolan; Li Jinye

    2007-01-01

    Biotechnology can be used to assess the well being of ecosystems, transform pollutants into benign substances, generate biodegradable materials from renewable sources, and develop environmentally safe manufacturing and disposal processes. Simultaneous elimination of sulfide and nitrite from synthetic wastewaters was investigated using a bioreactor. A laboratory scale anoxic sulfide-oxidizing (ASO) reactor was operated for 135 days to evaluate the potential for volumetric loading rates, effect of hydraulic retention time (HRT) and substrate concentration on the process performance. The maximal sulfide and nitrite removal rates were achieved to be 13.82 and 16.311 kg/(m 3 day), respectively, at 0.10 day HRT. The process can endure high sulfide concentrations, as the sulfide removal percentage always remained higher than 88.97% with influent concentration up to 1920 mg/L. Incomplete sulfide oxidation took place due to lower consumed nitrite to sulfide ratios of 0.93. It also tolerated high nitrite concentration up to 2265.25 mg/L. The potential achieved by decreasing HRT at fixed substrate concentration is higher than that by increasing substrate concentration at fixed HRT. The process can bear short HRT of 0.10 day but careful operation is needed. Nitrite conversion was more sensitive to HRT than sulfide conversion when HRT was decreased from 1.50 to 0.08 day. Stoichiometric analyses and results of batch experiments show that major part of sulfide (89-90%) was reduced by nitrite while some autooxidation (10-11%) was resulted from presence of small quantities of dissolved oxygen in the influent wastewater. There was ammonia amassing in considerably high amounts in the bioreactor when the influent nitrite concentration reached above 2265.25 mg/L. High ammonia concentrations (200-550 mg/L) in the bioreactor contributed towards the overall inhibition of the process. Present biotechnology exhibits practical value with a high potential for simultaneous removal of nitrite

  10. Dynamic of cadmium accumulation in the internal organs of rats after exposure to cadmium chloride and cadmium sulphide nanoparticules of various sizes

    Directory of Open Access Journals (Sweden)

    Apykhtina O.L.

    2017-06-01

    Full Text Available The article presents the results of study of cadmium accumulation in the internal organs of Wistar rats after prolonged intraperitoneal administration of cadmium chloride and cadmium sulphide nanoparticles of 4-6 nm and 9-11 nm in size in a dose of 0.08 mg /kg/day calculated as cadmium. Toxic effects were evaluated after 30 injections (1.5 months, 60 injections (3 months, and 1.5 months after the exposure has been ceased. The results of the study showed that the most intensive accumulation of cadmium was observed in the kidneys and liver of experimental animals, which is due to the peculiarities of the toxicokinetics and the route of administration of cadmium compounds. In the kidneys, spleen and thymus of animals exposed to cadmium sulphide nanoparticles, a greater concentration of cadmium than in the organs of animals exposed to cadmium chloride was found. Cadmium accumulated more intensively in the spleen after exposure to larger nanoparticles, than in the kidneys and thymus. In the liver, heart, aorta and brain significant accumulation was observed after cadmium chloride exposure.

  11. Cadmium exposure induces hematuria in Korean adults

    Energy Technology Data Exchange (ETDEWEB)

    Han, Seung Seok [Department of Internal Medicine, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Kim, Myounghee, E-mail: dkkim73@gmail.com [Department of Dental Hygiene, College of Health Science, Eulji University, Gyeonggi-do 461-713 (Korea, Republic of); Lee, Su Mi [Department of Internal Medicine, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Lee, Jung Pyo [Department of Internal Medicine, Seoul National University Boramae Medical Center, Seoul 156-707 (Korea, Republic of); Kim, Sejoong [Department of Internal Medicine, Seoul National University Bundang Hospital, Gyeonggi-do 463-707 (Korea, Republic of); Joo, Kwon Wook [Department of Internal Medicine, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of); Lim, Chun Soo [Department of Internal Medicine, Seoul National University Boramae Medical Center, Seoul 156-707 (Korea, Republic of); Kim, Yon Su; Kim, Dong Ki [Department of Internal Medicine, Seoul National University College of Medicine, Seoul 110-744 (Korea, Republic of)

    2013-07-15

    Introduction: Toxic heavy metals have adverse effects on human health. However, the risk of hematuria caused by heavy metal exposure has not been evaluated. Methods: Data from 4701 Korean adults were obtained in the Korean National Health and Nutritional Examination Survey (2008–2010). Blood levels of the toxic heavy metals cadmium, lead, and mercury were measured. Hematuria was defined as a result of ≥+1 on a urine dipstick test. The odds ratios (ORs) for hematuria were measured according to the blood heavy metal levels after adjusting for multiple variables. Results: Individuals with blood cadmium levels in the 3rd and 4th quartiles had a greater OR for hematuria than those in the 1st quartile group: 3rd quartile, 1.35 (1.019–1.777; P=0.037); 4th quartile, 1.52 (1.140–2.017; P=0.004). When blood cadmium was considered as a log-transformed continuous variable, the correlation between blood cadmium and hematuria was significant: OR, 1.97 (1.224–3.160; P{sub trend}=0.005). In contrast, no significant correlations between hematuria and blood lead or mercury were found in the multivariate analyses. Discussion: The present study shows that high cadmium exposure is associated with a risk of hematuria. -- Highlights: • A high level of blood cadmium is associated with a high risk of hematuria. • This correlation is independent of several confounding factors. • Blood levels of lead and mercury are not associated with risk of hematuria. • This is the first study on the correlation between cadmium exposure and hematuria risk.

  12. Carbon steel protection in G.S. (Girlder sulfide) plants. Pressure influence on iron sulfide scales formation. Pt. 5

    International Nuclear Information System (INIS)

    Delfino, C.A.; Lires, O.A.; Rojo, E.A.

    1987-01-01

    In order to protect carbon steel towers and piping of Girlder sulfide (G.S.) experimental heavy water plants against corrosion produced by the action of aqueous solutions of hydrogen sulfide, a method, previously published, was developed. Carbon steel, exposed to saturated aqueous solutions of hydrogen sulfide, forms iron sulfide scales. In oxygen free solutions evolution of corrosion follows the sequence: mackinawite → cubic ferrous sulfide → troilite → pyrrotite → pyrite. Scales formed by pyrrotite-pyrite or pyrite are the most protective layers (these are obtained at 130 deg C, 2MPa, for periods of 14 days). Experiments, at 125 deg C and periods of 10-25 days, were performed in two different ways: 1- constant pressure operations at 0.5 and 1.1 MPa. 2- variable pressure operation between 0.3-1 MPa. In all cases pyrrotite-pyrite scales were obtained. (Author) [es

  13. Uptake of cadmium from hydroponic solutions by willows ( Salix spp ...

    African Journals Online (AJOL)

    Salix integra 'Weishanhu') and Yizhibi (S. integra 'Yizhibi') were chosen as model plants to evaluate their potential for uptake of cadmium from hydroponic culture and relative uptake mechanism. Cadmium uptake showed a linear increase in the ...

  14. SUBSTITUTION OF CADMIUM CYANIDE ELECTROPLATING WITH ZINC CHLORIDE ELECTROPLATING

    Science.gov (United States)

    The study evaluated the zinc chloride electroplating process as a substitute for cadmium cyanide electroplating in the manufacture of industrial connectors and fittings at Aeroquip Corporation. The process substitution eliminates certain wastes, specifically cadmium and cyanide, ...

  15. Quantum optics

    Energy Technology Data Exchange (ETDEWEB)

    Drummond, P D [University of Queensland, St. Lucia, QLD (Australia).Physics Department

    1999-07-01

    Full text: Quantum optics in Australia has been an active research field for some years. I shall focus on recent developments in quantum and atom optics. Generally, the field as a whole is becoming more and more diverse, as technological developments drive experiments into new areas, and theorists either attempt to explain the new features, or else develop models for even more exotic ideas. The recent developments include quantum solitons, quantum computing, Bose-Einstein condensation, atom lasers, quantum cryptography, and novel tests of quantum mechanics. The talk will briefly cover current progress and outstanding problems in each of these areas. Copyright (1999) Australian Optical Society.

  16. Cadmium Exposure is Associated with the Prevalence of Dyslipidemia

    OpenAIRE

    Zhou Zhou; Yong-hui Lu; Hui-feng Pi; Peng Gao; Min Li; Lei Zhang; Li-ping Pei; Xiang Mei; Lin Liu; Qi Zhao; Qi-Zhong Qin; Yu Chen; Yue-ming Jiang; Zhao-hui Zhang; Zheng-ping Yu

    2016-01-01

    Background: Cadmium is a widespread environmental and occupational pollutant that accumulates in human body with a biological half-life exceeding 10 years. Cadmium exposure has been demonstrated to increase rates of cardiovascular diseases. Whether occupational cadmium exposure is associated with the increase in the prevalence of dyslipidemia and hence contributes to the risk of cardiovascular diseases is still equivocal. To test the hypothesis that exposure to cadmium is related to the preva...

  17. An assessment of the effects of a cadmium discharge ordinance

    International Nuclear Information System (INIS)

    Moser, J.H.; Schultz, J.L.

    1982-01-01

    The problem facing the MMSD was high levels of cadmium in Milorganite fertilizer. The cause was determined to be discharges from industry, primarily electroplaters. The solution was the cooperative development of an ordinance to limit the discharge of cadmium. Because the dischargers acted responsibly to comply with the ordinance, the ordinance succeeded in achieving its objective of significantly reducing the cadmium loading to the municipal sewerage system and subsequently reducing the cadmium concentration in Milorganite fertilizer

  18. Occupational exposure to hydrogen sulfide: management of hydrogen sulfide exposure victims (Preprint No. SA-5)

    International Nuclear Information System (INIS)

    Srivastava, P.P.

    1989-04-01

    National Institute of Occupational Safety and Health, U.S.A. has listed 73 industries with potential exposure to hydrogen sulphide. Though the toxicity of hydrogen sulfide is known to mankind since the beginning of seventeenth century the exact mode of its toxicity and effective therapeutic regimen remains unclear as yet. This paper presents current thoughts on the toxicity of this substance and a discussion on the role of various antidotes used in H 2 S poisoning. (autho r)

  19. Cadmium exposure and health risks: Recent findings

    Energy Technology Data Exchange (ETDEWEB)

    Elinder, C.G. [Huddinge Hospital (Sweden). Dept. of Renal Medicine; Jaerup, L. [Stockholm City Council (Sweden). Dept. of Environmental Health

    1996-08-01

    Environmental and/or occupational exposure to cadmium give rise to a tubular kidney dysfunction which may proceed to more generalized renal damage and bone disease if exposure has been high and prolonged. Recent scientific work shows that early renal effects develop at lower levels of exposure than previously anticipated. Previous risk assessments for cadmium were mainly based on studies on healthy male workers. The general population, however, also include particularly susceptible groups such as elderly and individuals with illnesses (e.g. diabetes) that may predispose to cadmium-induced health effects. A significant proportion of the general population displays early signs of toxicity already at urinary cadmium concentrations around 3 nmol mmol{sup -1} creatinine. In addition to early tubular effects, cadmium may exert direct or indirect effects on mineral metabolism and the mineralization of the skeleton at relatively low levels of exposure. This may have important health implications, as poor and easily fractured bone is a major problem among the elderly in all industrialized countries. 41 refs, 4 figs

  20. Fluorescence Quenching of Dendrimer-Encapsulated CdS Quantum Dots for the Detection of H{sub 2}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Hyojung; Kim, Hai Dong; Kim, Joohoon [Kyung Hee Un iversity, Seoul (Korea, Republic of)

    2016-02-15

    Hydrogen peroxide (H{sub 2}O{sub 2}) exists in natural environments as a byproduct of various enzymatic and photochemical reactions. Various approaches have been reported for the synthesis of cadmium sulfide (CdS) QDs using dendrimers, which can be categorized mainly into two general approaches. The first approach utilizes dendrimers as capping agents, resulting in the formation of agglomerates of spatially segregated QDs stabilized by multiple dendrimers. We have described the synthesis and characterization of the CdS QDs using G6-NH{sub 2} dendrimers. By controlling the molar ratios (n = Cd2+/G6-NH{sub 2}) between the Cd{sup 2+} ions and G6-NH{sub 2} dendrimers, we synthesized a set of CdS QDs with different structural and optical properties. Importantly, the synthesized CdS QDs exhibited H{sub 2}O{sub 2}-sensitive fluorescence, which can be utilized for the detection of H{sub 2}O{sub 2}. Especially, the CdS QDs with n = 64 displayed a Stern–Volmer relationship between the fluorescence of the CdS QDs and the concentration of H{sub 2}O{sub 2}, as well as the strongest fluorescence among the set of the synthesized CdS QDs. Since core-shell structures of QDs often result in enhanced stability and quantum efficiency of the QDs, we are currently working on core-shell structured QDs prepared using dendrimers to improve their stability and quantum yield compared to the CdS QDs reported in the present study.

  1. Quantum entanglement and quantum teleportation

    International Nuclear Information System (INIS)

    Shih, Y.H.

    2001-01-01

    One of the most surprising consequences of quantum mechanics is the entanglement of two or more distance particles. The ''ghost'' interference and the ''ghost'' image experiments demonstrated the astonishing nonlocal behavior of an entangled photon pair. Even though we still have questions in regard to fundamental issues of the entangled quantum systems, quantum entanglement has started to play important roles in quantum information and quantum computation. Quantum teleportation is one of the hot topics. We have demonstrated a quantum teleportation experiment recently. The experimental results proved the working principle of irreversibly teleporting an unknown arbitrary quantum state from one system to another distant system by disassembling into and then later reconstructing from purely classical information and nonclassical EPR correlations. The distinct feature of this experiment is that the complete set of Bell states can be distinguished in the Bell state measurement. Teleportation of a quantum state can thus occur with certainty in principle. (orig.)

  2. Azo dye decolorization assisted by chemical and biogenic sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Prato-Garcia, Dorian [Laboratory for Research on Advanced Processes for Water Treatment, Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, Querétaro 76230 (Mexico); Cervantes, Francisco J. [División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa de San José 2055, San Luis Potosí 78216 (Mexico); Buitrón, Germán, E-mail: gbuitronm@ii.unam.mx [Laboratory for Research on Advanced Processes for Water Treatment, Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, Querétaro 76230 (Mexico)

    2013-04-15

    Highlights: ► Azo dyes were reduced efficiently by chemical and biogenic sulfide. ► Biogenic sulfide was more efficient than chemical sulfide. ► There was no competition between dyes and sulfate for reducing equivalents. ► Aromatic amines barely affected the sulfate-reducing process. -- Abstract: The effectiveness of chemical and biogenic sulfide in decolorizing three sulfonated azo dyes and the robustness of a sulfate-reducing process for simultaneous decolorization and sulfate removal were evaluated. The results demonstrated that decolorization of azo dyes assisted by chemical sulfide and anthraquinone-2,6-disulfonate (AQDS) was effective. In the absence of AQDS, biogenic sulfide was more efficient than chemical sulfide for decolorizing the azo dyes. The performance of sulfate-reducing bacteria in attached-growth sequencing batch reactors suggested the absence of competition between the studied azo dyes and the sulfate-reducing process for the reducing equivalents. Additionally, the presence of chemical reduction by-products had an almost negligible effect on the sulfate removal rate, which was nearly constant (94%) after azo dye injection.

  3. Simultaneous removal of sulfide, nitrate and acetate: Kinetic modeling

    Energy Technology Data Exchange (ETDEWEB)

    Wang Aijie, E-mail: waj0578@hit.edu.cn [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (SKLUWRE, HIT), Harbin 150090 (China); Liu Chunshuang; Ren Nanqi; Han Hongjun [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (SKLUWRE, HIT), Harbin 150090 (China); Lee Duujong [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (SKLUWRE, HIT), Harbin 150090 (China); Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2010-06-15

    Biological removal of sulfide, nitrate and chemical oxygen demand (COD) simultaneously from industrial wastewaters to elementary sulfur (S{sup 0}), N{sub 2}, and CO{sub 2}, or named the denitrifying sulfide (DSR) process, is a cost effective and environmentally friendly treatment process for high strength sulfide and nitrate laden organic wastewater. Kinetic model for the DSR process was established for the first time on the basis of Activated Sludge Model No. 1 (ASM1). The DSR experiments were conducted at influent sulfide concentrations of 200-800 mg/L, whose results calibrate the model parameters. The model correlates well with the DSR process dynamics. By introducing the switch function and the inhibition function, the competition between autotrophic and heterotrophic denitrifiers is quantitatively described and the degree of inhibition of sulfide on heterotrophic denitrifiers is realized. The model output indicates that the DSR reactor can work well at 0.5 < C/S < 3.0 with influent sulfide concentration of 400-1000 mg/L. At >1000 mg/L influent sulfide, however, the DSR system will break down.

  4. Uptake of cadmium from hydroponic solutions by willows (Salix spp ...

    African Journals Online (AJOL)

    DR. NJ TONUKARI

    2011-11-16

    Nov 16, 2011 ... which indicated that cadmium uptake across the plasma membrane was ... to cadmium pollution in water-soil-plant systems because .... plants were separated into roots and shoots, blotted dry with paper tissue .... Analysis of the kinetic constants for cadmium uptake ..... proteins (Welch and Norvell, 1999).

  5. Cadmium affects the social behaviour of rainbow trout, Oncorhynchus mykiss

    International Nuclear Information System (INIS)

    Sloman, Katherine A.; Scott, Graham R.; Diao Zhongyu; Rouleau, Claude; Wood, Chris M.; McDonald, D. Gord

    2003-01-01

    The present study investigated both the effects of cadmium on the social interactions of rainbow trout and the differential accumulation of waterborne cadmium among social ranks of fish. Fish exposed to waterborne cadmium concentrations of 2 μg l -1 for 24 h, followed by a 1, 2 or 3 day depuration period in clean water, had a decreased ability to compete with non-exposed fish. However, the competitive ability of exposed fish given a 5 day depuration period was not significantly impaired. Cadmium accumulated in the olfactory apparatus of fish exposed to waterborne cadmium for 24 h and decreased significantly only after 5 days depuration in clean water. Among groups of ten fish held in stream tanks, where all fish were exposed to cadmium, there were significant effects on social behaviour and growth rate. Dominance hierarchies formed faster among fish exposed to cadmium than among control fish, and overall growth rates were higher in the cadmium treatment. In groups of ten fish, social status also affected tissue accumulation of cadmium during waterborne exposure, with dominant fish accumulating more cadmium at the gill. In conclusion, exposure to low levels of cadmium, affects the social behaviour of fish, in part due to accumulation in the olfactory apparatus, and dominant fish accumulate more gill cadmium than subordinates during chronic waterborne exposure

  6. Modeling cadmium in the feed chain and cattle organs

    NARCIS (Netherlands)

    Fels-Klerx, van der H.J.; Romkens, P.F.A.M.; Franz, E.; Raamsdonk, van L.W.D.

    2011-01-01

    The objectives of this study were to estimate cadmium contamination levels in different scenarios related to soil characteristics and assumptions regarding cadmium accumulation in the animal tissues, using quantitative supply chain modeling. The model takes into account soil cadmium levels, soil pH,

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

    Science.gov (United States)

    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.

  8. A membrane electrode assembled photoelectrochemical cell with a solar-responsive cadmium sulfide-zinc sulfide-titanium dioxide/mesoporous silica photoanode

    Science.gov (United States)

    Chen, Ming; Chen, Rong; Zhu, Xun; Liao, Qiang; An, Liang; Ye, Dingding; Zhou, Yuan; He, Xuefeng; Zhang, Wei

    2017-12-01

    In this work, a membrane electrode assembled photoelectrochemical cell (PEC) is developed for the electricity generation by degrading the organic compounds. The photocatalyst is prepared by the incorporation of mesoporous silica SBA-15 into TiO2 and the photosensitization of CdS-ZnS to enhance the photoanode performance, while the cathode employs the air-breathing mode to enhance the oxygen transport. The experimental results show that the developed PEC exhibits good photoresponse to the illumination and the appropriate SBA-15 mass ratio in the photoanode enables the enhancement of the performance. It is also shown that the developed PEC yields better performance in the alkaline environment than that in the neutral environment. Increasing the KOH concentration can improve the cell performance. There exist optimal liquid flow rate and organics concentration leading to the best performance. Besides, it is found that increasing the light intensity can generate more electron-hole pairs and thus enhance the cell performance. These results are helpful for optimizing the design.

  9. Interactions among sulfide-oxidizing bacteria

    Science.gov (United States)

    Poplawski, R.

    1985-01-01

    The responses of different phototrophic bacteria in a competitive experimental system are studied, one in which primary factors such as H2S or light limited photometabolism. Two different types of bacteria shared one limited source of sulfide under specific conditions of light. The selection of a purple and a green sulfur bacteria and the cyanobacterium was based on their physiological similarity and also on the fact that they occur together in microbial mats. They all share anoxygenic photosynthesis, and are thus probably part of an evolutionary continuum of phototrophic organisms that runs from, strictly anaerobic physiology to the ability of some cyanobacteria to shift between anoxygenic bacterial style photosynthesis and the oxygenic kind typical of eukaryotes.

  10. Eelgrass fairy rings: sulfide as inhibiting agent

    DEFF Research Database (Denmark)

    Borum, Jens; Raun, Ane-Marie Løvendahl; Hasler-Sheetal, Harald

    2014-01-01

    specifically, for the apparent die- off of eelgrass shoots on the inner side of the rings. The fairy rings were up to 15 m in diameter consisting of 0.3- to 1-m-wide zones of sea grass shoots at densities of up to 1,200 shoots m−2 and rooted in an up to 10-cm-thick sediment layer. On the outer side, shoots...... expanded over the bare chalk plates. On the inner side, shoots were smaller, had lower absolute and specific leaf growth, shoot density was lower and the sediment eroded leaving the bare chalk with scattered boulders behind. Sediment organic matter and nutrients and tissue nutrient contents were...... substantial invasion of sulfide from the sediment. neither the clonal growth pattern of eelgrass, sediment burial of shoots, hydrodynamic forcing nor nutrient limitation could explain the ring-shaped pattern. We conclude that the most likely explanation must be found in invasion of eelgrass shoots by toxic...

  11. On the pelletizing of sulfide molybdenite concentrate

    International Nuclear Information System (INIS)

    Palant, A.A.

    2007-01-01

    Investigation results are discussed on the process of pelletizing with the use of various binders (water, syrup, sulfite-alcoholic residue and bentonite) for flotation sulfide molybdenite concentrate (∼84 % MoS 2 ) of the Mongolian deposit. It is established that with the use of syrup rather strong pellets (>300 g/p) of desired size (2-3 mm) can be obtained at a binder flowrate of 1 kg per 100 kg of concentrate. The main advantage of using syrup instead of bentonite lies in the fact that in this instance no depletion of a molybdenum calcine obtained by oxidizing roasting of raw ore takes place due to syrup complete burning out. This affects positively subsequent hydrometallurgical conversion because of decreasing molybdenum losses with waste cakes [ru

  12. Modulated structure calculated for superconducting hydrogen sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Majumdar, Arnab; Tse, John S.; Yao, Yansun [Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, SK (Canada)

    2017-09-11

    Compression of hydrogen sulfide using first principles metadynamics and molecular dynamics calculations revealed a modulated structure with high proton mobility which exhibits a diffraction pattern matching well with experiment. The structure consists of a sublattice of rectangular meandering SH{sup -} chains and molecular-like H{sub 3}S{sup +} stacked alternately in tetragonal and cubic slabs forming a long-period modulation. The novel structure offers a new perspective on the possible origin of the superconductivity at very high temperatures in which the conducting electrons in the SH chains are perturbed by the fluxional motions of the H{sub 3}S resulting in strong electron-phonon coupling. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Mechanism of hydrodenitrogenation on phosphides and sulfides.

    Science.gov (United States)

    Oyama, S Ted; Lee, Yong-Kul

    2005-02-17

    The mechanism of hydrodenitrogenation (HDN) of 2-methylpiperidine was studied over a silica-supported nickel phosphide catalyst (Ni2P/SiO2, Ni/P = 1/2) and a commercial Ni-Mo-S/Al2O3 catalyst in a three-phase trickle-bed reactor operated at 3.1 MPa and 450-600 K. Analysis of the product distribution as a function of contact time indicated that the reaction proceeded in both cases predominantly by a substitution mechanism, with a smaller contribution of an elimination mechanism. Fourier transform infrared spectroscopy (FTIR) of the 2-methylpiperidine indicated that at reaction conditions a piperidinium ion intermediate was formed on both the sulfide and the phosphide. It is concluded that the mechanism of HDN on nickel phosphide is very similar to that on sulfides. The mechanism on the nickel phosphide was also probed by comparing the reactivity of piperidine and several of its derivatives in the presence of 3000 ppm S. The relative elimination rates depended on the structure of the molecules, and followed the sequence: 4-methylpiperidine approximately piperidine > 3-methylpiperidine > 2,6-dimethylpiperidine > 2-methylpiperidine. [Chemical structure: see text] This order of reactivity was not dependent on the number of alpha-H or beta-H atoms in the molecules, ruling out their reaction through a single, simple mechanism. It is likely that the unhindered piperidine molecules reacted by an S(N)2 substitution process and the more hindered 2,6-dimethylpiperidine reacted by an E2 elimination process.

  14. New cyclic sulfides, garlicnins I2, M, N, and O, from Allium sativum.

    Science.gov (United States)

    Nohara, Toshihiro; Ono, Masateru; Nishioka, Naho; Masuda, Fuka; Fujiwara, Yukio; Ikeda, Tsuyoshi; Nakano, Daisuke; Kinjo, Junei

    2018-01-01

    One atypical thiolane-type sulfide, garlicnin I 2 (1), two 3,4-dimethylthiolane-type sulfides, garlicnins M (2) and N (3), and one thiabicyclic-type sulfide, garlicnin O (4), were isolated from the acetone extracts of Chinese garlic bulbs, Allium sativum and their structures were characterized. Hypothetical pathways for the production of the respective sulfides were discussed.

  15. Quantum robots and quantum computers

    Energy Technology Data Exchange (ETDEWEB)

    Benioff, P.

    1998-07-01

    Validation of a presumably universal theory, such as quantum mechanics, requires a quantum mechanical description of systems that carry out theoretical calculations and systems that carry out experiments. The description of quantum computers is under active development. No description of systems to carry out experiments has been given. A small step in this direction is taken here by giving a description of quantum robots as mobile systems with on board quantum computers that interact with different environments. Some properties of these systems are discussed. A specific model based on the literature descriptions of quantum Turing machines is presented.

  16. Quantum computers and quantum computations

    International Nuclear Information System (INIS)

    Valiev, Kamil' A

    2005-01-01

    This review outlines the principles of operation of quantum computers and their elements. The theory of ideal computers that do not interact with the environment and are immune to quantum decohering processes is presented. Decohering processes in quantum computers are investigated. The review considers methods for correcting quantum computing errors arising from the decoherence of the state of the quantum computer, as well as possible methods for the suppression of the decohering processes. A brief enumeration of proposed quantum computer realizations concludes the review. (reviews of topical problems)

  17. Optimization of the superconducting phase of hydrogen sulfide

    Science.gov (United States)

    Degtyarenko, N. N.; Masur, E. A.

    2015-12-01

    The electron and phonon spectra, as well as the densities of electron and phonon states of the SH3 phase and the stable orthorhombic structure of hydrogen sulfide SH2, are calculated for the pressure interval 100-225 GPa. It is found that the I4/ mmm phase can be responsible for the superconducting properties of metallic hydrogen sulfide along with the SH3 phase. Sequential stages for obtaining and conservation of the SH2 phase are proposed. The properties of two (SH2 and SH3) superconducting phases of hydrogen sulfide are compared.

  18. Process for scavenging hydrogen sulfide from hydrocarbon gases

    International Nuclear Information System (INIS)

    Fox, I.

    1981-01-01

    A process for scavenging hydrogen sulfide from hydrocarbon gases utilizes iron oxide particles of unique chemical and physical properties. These particles have large surface area, and are comprised substantially of amorphous Fe 2 O 3 containing a crystalline phase of Fe 2 O 3 , Fe 3 O 4 and combinations thereof. In scavenging hydrogen sulfide, the iron oxide particles are suspended in a liquid which enters into intimate mixing contact with hydrocarbon gases; the hydrogen sulfide is reacted at an exceptional rate and only acid-stable reaction products are formed. Thereafter, the sweetened hydrocarbon gases are collected

  19. Sulfidization of an aluminocobaltomolybdenum catalyst using the 35S radioisotope

    International Nuclear Information System (INIS)

    Isagulyants, G.V.; Greish, A.A.; Kogan, V.M.

    1987-01-01

    It has been established that in aluminocobaltomolybdenum catalyst sulfidized with elemental sulfur there are two types of sulfur, free and bound. The maximum amount of bound sulfur in ACM catalyst is 6.6 wt. %, which corresponds to practically complete sulfidation of the ACM catalyst. In the presence of hydrogen an equilibrium distribution of bound sulfur is achieved in a granule of ACM catalyst irrespective of the temperature of sulfidation. In a nitrogen atmosphere it is primarily the surface layers of the catalyst that are sulfured

  20. Sulfide Oxidation in the Anoxic Black-Sea Chemocline

    DEFF Research Database (Denmark)

    JØRGENSEN, BB; FOSSING, H.; WIRSEN, CO

    1991-01-01

    per day, occurred in anoxic water at the top of the sulfide zone concurrent with the highest rates of dark CO2 assimilation. The main soluble oxidized products of sulfide were thiosulfate (68-82%) and sulfate. Indirect evidence was presented for the formation of elemental sulfur which accumulated...... that the measured H2S oxidation rates were 4-fold higher than could be explained by the downward flux of organic carbon and too high to balance the availability of electron acceptors such as oxidized iron or manganese. A nitrate maximum at the lower boundary of the O2 zone did not extend down to the sulfide zone....

  1. Thermoelectric properties of non-stoichiometric lanthanum sulfides

    International Nuclear Information System (INIS)

    Shapiro, E.; Danielson, L.R.

    1983-01-01

    The lanthanum sulfides are promising candidate materials for high-efficiency thermoelectric applications at temperatures up to 1300 0 C. The nonstoichiometric lanthanum sulfides (LaS /SUB x/ , where 1.33 2 //rho/ can be chosen. The thermal conductivity remains approximately constant with stoichiometry, so a material with an optimum value of α 2 //rho/ should possess the optimum figure-of-merit. Data for the Seebeck coefficient and electrical resistivity of non-stoichiometric lanthanum sulfides is presented, together with structural properties of these materials

  2. Denitrifying sulfide removal process on high-salinity wastewaters.

    Science.gov (United States)

    Liu, Chunshuang; Zhao, Chaocheng; Wang, Aijie; Guo, Yadong; Lee, Duu-Jong

    2015-08-01

    Denitrifying sulfide removal (DSR) process comprising both heterotrophic and autotrophic denitrifiers can simultaneously convert nitrate, sulfide, and acetate into nitrogen gas, elemental sulfur (S(0)), and carbon dioxide, respectively. Sulfide- and nitrate-laden wastewaters at 2-35 g/L NaCl were treated by DSR process. A C/N ratio of 3:1 was proposed to maintain high S(0) conversion rate. The granular sludge with a compact structure and smooth outer surface was formed. The microbial communities of DSR consortium via high-throughput sequencing method suggested that salinity shifts the predominating heterotrophic denitrifiers at 10 g/L NaCl.

  3. Use of sulfide-containing liquors for removing mercury from flue gases

    Science.gov (United States)

    Nolan, Paul S.; Downs, William; Bailey, Ralph T.; Vecci, Stanley J.

    2006-05-02

    A method and apparatus for reducing and removing mercury in industrial gases, such as a flue gas, produced by the combustion of fossil fuels, such as coal, adds sulfide ions to the flue gas as it passes through a scrubber. Ideally, the source of these sulfide ions may include at least one of: sulfidic waste water, kraft caustic liquor, kraft carbonate liquor, potassium sulfide, sodium sulfide, and thioacetamide. The sulfide ion source is introduced into the scrubbing liquor as an aqueous sulfide species. The scrubber may be either a wet or dry scrubber for flue gas desulfurization systems.

  4. Remediation of Sulfidic Wastewater by Aeration in the Presence of Ultrasonic Vibration

    Directory of Open Access Journals (Sweden)

    F. Ahmad

    2018-06-01

    Full Text Available In the current study, the aerial oxidation of sodium sulfide in the presence of ultrasonic vibration is investigated. Sulfide analysis was carried out by the methylene blue method. Sodium sulfide is oxidized to elemental sulfur in the presence of ultrasonic vibration. The influence of air flow rate, initial sodium sulfide concentration and ultrasonic vibration intensity on the oxidation of sodium sulfide was investigated. The rate law equation regarding the oxidation of sulfide was determined from the experimental data. The order of reaction with respect to sulfide and oxygen was found to be 0.36 and 0.67 respectively. The overall reaction followed nearly first order kinetics.

  5. Quantum mystery

    CERN Document Server

    Chanda, Rajat

    1997-01-01

    The book discusses the laws of quantum mechanics, several amazing quantum phenomena and some recent progress in understanding the connection between the quantum and the classical worlds. We show how paradoxes arise and how to resolve them. The significance of Bell's theorem and the remarkable experimental results on particle correlations are described in some detail. Finally, the current status of our understanding of quantum theory is summerised.

  6. Analysis of cadmium in high alpha solutions

    International Nuclear Information System (INIS)

    Gray, L.W.; Overman, L.A.; Hodgens, H.F.

    1977-07-01

    Cadmium nitrate is occasionally used as a neutron poison for convenience in the separation of uranium, neptunium, and plutonium. As the classical methods of analysis for cadmium are very time-consuming, a method to isolate it in solution using solvent extraction of uranium, neptunium, and plutonium with TBP in an n-paraffin hydrocarbon was investigated. After removal of the radionuclides, the cadmium is determined by atomic absorption spectroscopy. Precision of the method at the 95 percent confidence level is +-2.4 percent. Alpha content of the solutions was typically reduced from 1-10 x 10 11 dis/(min ml) 238 Pu to 1-15 x 10 4 dis/(min ml). Analysis time was typically reduced from approximately 24 hours per sample to less than 1 hour

  7. Bireactor Electronuclear Systems with Liquid Cadmium Valve

    CERN Document Server

    Bznuni, S A; Zhamkochyan, V M; ASosnin, A N; Polanski, A; Khudaverdyan, A H

    2002-01-01

    Three main types of bireactor electronuclear systems are discussed. From the point of view of assuring high level of functional characteristics and safety bireactor electronuclear systems with booster using enriched uranium (20 %) and with a liquid cadmium valve appears to be the most effective. It is shown by means of Monte-Carlo modeling that such operation conditions can be achieved which lead to the destruction of the intermediate cadmium layer making the systems supercritical (k_{eff}>1). One can avoid the problem by using a special design of the liquid cadmium valve. In comparison with other nuclear systems (critical reactors, one-reactor electronuclear systems) cascade electronuclear systems have essential advantages allowing the decrease of the proton beam current by one order of magnitude and providing at same time the necessary level of power generation and neutron flux. Availability of both the thermal and fast cones allows one to transmute not only transuranics but also the fission products - cesi...

  8. Cadmium accumulation by Axonopus compressus (Sw. P. Beauv and Cyperus rotundas Linn growing in cadmium solution and cadmium-zinc contaminated soil

    Directory of Open Access Journals (Sweden)

    Paitip Thiravetyan

    2007-05-01

    Full Text Available This research investigated the phyto-remediation potentials of Cyperus rotundas Linn (Nutgrass and Axonopus compressus (Sw. P. Beauv (Carpetgrass for cadmium removal from cadmium solution andcadmium-zinc contaminated soil. Plants growth in the solution showed that cadmium decreased the relative growth rate of both grasses. However, the amount of cadmium accumulated in shoot and root was increasedwith the increase in cadmium concentration and exposure time. Growth in fertile soil mixed with Cd-contaminated zinc silicate residue (65% Si, 19% Ca, 2% Zn, 1% Mg and 0.03% Cd at the ratio of 50:50 (w/wfor 30 days showed that C. rotundas Linn accumulated cadmium in root and shoot to 2,178 and 1,144 mg kg-1 dry weight, respectively. A. compressus (Sw. P. Beauv accumulated cadmium in root and shoot to 1,965and 669 mg kg-1 dry weight, respectively. Scanning electron microscope connected to energy-dispersive X-ray spectroscopy suggested that the mechanism of cadmium accumulation by both grasses involved thecadmium precipitation in the stable form of cadmium silicate, which indicated that C. rotundas Linn and A. compressus (Sw. P. Beauv could be grown to prevent soil erosion and to remediate cadmium-contaminatedsoil.

  9. Reduction of Cadmium Uptake of Rice Plants Using Soil Amendments in High Cadmium Contaminated Soil: A Pot Experiment

    Directory of Open Access Journals (Sweden)

    Dian Siswanto

    2013-05-01

    Full Text Available The aims of this study were to investigate the effect of agricultural residues on reducing cadmium uptake in rice plants. The rice plants growing on no cadmium/free cadmium soils (N, Cd soils (Cds, and Cd soils each amended with 1% w/w of coir pith (CP, coir pith modified with sodium hydroxide (CPm and corncob (CC under high cadmium contaminated soil with an average 145 mg Cd kg-1 soil were investigated. The results showed that the cumulative transpiration of rice grown in various treatments under high cadmium contaminated soil followed the order: Cds > CPm ≥ CP ≥ CC. These transpirations directly influenced cadmium accumulation in shoots and husks of rice plants. The CC and CP seemed to work to reduce the cadmium uptake by rice plants indicated by accumulated cadmium in the husk that were 2.47 and 7.38 mg Cd kg-1 dry weight, respectively. Overall, transpiration tended to drive cadmium accumulation in plants for rice grown in high cadmium contaminated soil. The more that plants uptake cadmium, the lower cadmium that remains in the soil.

  10. Effects of cadmium and mycorrhizal fungi on growth, fitness, and cadmium accumulation in flax (Linum usitatissimum; Linaceae).

    Science.gov (United States)

    Hancock, Laura M S; Ernst, Charlotte L; Charneskie, Rebecca; Ruane, Lauren G

    2012-09-01

    Agricultural soils have become contaminated with a variety of heavy metals, including cadmium. The degree to which soil contaminants affect plants may depend on symbiotic relationships between plant roots and soil microorganisms. We examined (1) whether mycorrhizal fungi counteract the potentially negative effects of cadmium on the growth and fitness of flax (Linum usitatissimum) and (2) whether mycorrhizal fungi affect the accumulation of cadmium within plant parts. Two flax cultivars (Linott and Omega) were grown in three soil cadmium environments (0, 5, and 15 ppm). Within each cadmium environment, plants were grown in either the presence or absence of mycorrhizal fungi. Upon senescence, we measured growth and fitness and quantified the concentration of cadmium within plants. Soil cadmium significantly decreased plant fitness, but did not affect plant growth. Mycorrhizal fungi, which were able to colonize roots of plants growing in all cadmium levels, significantly increased plant growth and fitness. Although mycorrhizal fungi counteracted the negative effects of cadmium on fruit and seed production, they also enhanced the concentration of cadmium within roots, fruits, and seeds. The degree to which soil cadmium affects plant fitness and the accumulation of cadmium within plants depended on the ability of plants to form symbiotic relationships with mycorrhizal fungi. The use of mycorrhizal fungi in contaminated agricultural soils may offset the negative effects of metals on the quantity of seeds produced, but exacerbate the accumulation of these metals in our food supply.

  11. Sulfide precursor concentration and lead source effect on PbS thin films properties

    International Nuclear Information System (INIS)

    Beddek, L.; Messaoudi, M.; Attaf, N.; Aida, M.S.; Bougdira, J.

    2016-01-01

    Lead sulfide (PbS) thin films were synthesized using chemical bath deposition (CBD). Bath solutions are formed of various concentrations of thiourea, sulfide source, ranged from 0.6 to 1.2 M and two different salts as Pb source (lead acetate and lead nitrate). From the growth mechanism, we inferred that PbS is formed through the ion by ion process when using acetate lead source, while, using nitrate source yields to films growth through the complex-decomposition process. Due to the difference in the involved growth process, lead acetate produces films with larger crystallite size (from 4 to 16 nm), smooth and dense films. However, lead nitrate produces rough films with smaller crystallite size (from 1 to 4 nm). Increasing the thiourea concentration results in crystallinity improvement when using lead acetate and, oppositely, in crystallinity degradation when using lead nitrate. Due to the quantum effect caused by the small crystallite sizes, the films optical gap is varied from 0.5 to 0.9 eV. - Highlights: • PbS thin films were synthesized by chemical bath deposition. • Ion by ion is the growth process when using the acetate lead source. • Deposition process is by complex-decomposition when using nitrate source. • Lead acetate yields to dense films with larger crystallite size. • Lead nitrate produces rough films with smaller crystallite size.

  12. Sulfide precursor concentration and lead source effect on PbS thin films properties

    Energy Technology Data Exchange (ETDEWEB)

    Beddek, L.; Messaoudi, M.; Attaf, N. [Laboratoire Couche Minces et Interfaces, Université frères Mentouri Constantine, 25000, Constantine (Algeria); Aida, M.S., E-mail: aida_salah2@yahoo.fr [Laboratoire Couche Minces et Interfaces, Université frères Mentouri Constantine, 25000, Constantine (Algeria); Bougdira, J. [Université de Lorraine, Institut Jean Lamour UMR 7198, Vandoeuvre 54506 (France)

    2016-05-05

    Lead sulfide (PbS) thin films were synthesized using chemical bath deposition (CBD). Bath solutions are formed of various concentrations of thiourea, sulfide source, ranged from 0.6 to 1.2 M and two different salts as Pb source (lead acetate and lead nitrate). From the growth mechanism, we inferred that PbS is formed through the ion by ion process when using acetate lead source, while, using nitrate source yields to films growth through the complex-decomposition process. Due to the difference in the involved growth process, lead acetate produces films with larger crystallite size (from 4 to 16 nm), smooth and dense films. However, lead nitrate produces rough films with smaller crystallite size (from 1 to 4 nm). Increasing the thiourea concentration results in crystallinity improvement when using lead acetate and, oppositely, in crystallinity degradation when using lead nitrate. Due to the quantum effect caused by the small crystallite sizes, the films optical gap is varied from 0.5 to 0.9 eV. - Highlights: • PbS thin films were synthesized by chemical bath deposition. • Ion by ion is the growth process when using the acetate lead source. • Deposition process is by complex-decomposition when using nitrate source. • Lead acetate yields to dense films with larger crystallite size. • Lead nitrate produces rough films with smaller crystallite size.

  13. Quantum criticality.

    Science.gov (United States)

    Coleman, Piers; Schofield, Andrew J

    2005-01-20

    As we mark the centenary of Albert Einstein's seminal contribution to both quantum mechanics and special relativity, we approach another anniversary--that of Einstein's foundation of the quantum theory of solids. But 100 years on, the same experimental measurement that puzzled Einstein and his contemporaries is forcing us to question our understanding of how quantum matter transforms at ultra-low temperatures.

  14. Quantum Computing

    Indian Academy of Sciences (India)

    In the first part of this article, we had looked at how quantum physics can be harnessed to make the building blocks of a quantum computer. In this concluding part, we look at algorithms which can exploit the power of this computational device, and some practical difficulties in building such a device. Quantum Algorithms.

  15. I, Quantum Robot: Quantum Mind control on a Quantum Computer

    OpenAIRE

    Zizzi, Paola

    2008-01-01

    The logic which describes quantum robots is not orthodox quantum logic, but a deductive calculus which reproduces the quantum tasks (computational processes, and actions) taking into account quantum superposition and quantum entanglement. A way toward the realization of intelligent quantum robots is to adopt a quantum metalanguage to control quantum robots. A physical implementation of a quantum metalanguage might be the use of coherent states in brain signals.

  16. Solvent extraction studies on cadmium Part 3

    International Nuclear Information System (INIS)

    Alian, A.; El-Kot, A.

    1976-01-01

    An extraction study was performed on various concentrations of cadmium, zinc and cobalt halides in the presence of sulphuric acid. A long chain amine (Amberlite LA-2) and an organophosphorus solvent (TBP) were used. In most cases the value of the distribution ratio decreases with the increase of metal concentration in the aqueous phase. The various possibilities of chemical and radiochemical separations of cadmium from accompanying metal species are reported: separation of (sup109m)Ag from irradiated Cd targets, separation of (sup115m)In using HDEHP, separation of Cd and Zn from their mixtures. (T.G.)

  17. Environmental cadmium and breast cancer risk

    OpenAIRE

    Gallagher, Carolyn M.; Chen, John J.; Kovach, John S.

    2010-01-01

    Breast cancer is the most prevalent women's cancer, with an age-adjusted incidence of 122.9 per 100,000 US women. Cadmium, a ubiquitous carcinogenic pollutant with multiple biological effects, has been reported to be associated with breast cancer in one US regional case-control study. We examined the association of breast cancer with urinary cadmium (UCd), in a case-control sample of women living on Long Island (LI), NY (100 with breast cancer and 98 without), a region with an especially high...

  18. Enhanced sulfidation xanthate flotation of malachite using ammonium ions as activator

    OpenAIRE

    Dandan Wu; Wenhui Ma; Yingbo Mao; Jiushuai Deng; Shuming Wen

    2017-01-01

    In this study, ammonium ion was used to enhance the sulfidation flotation of malachite. The effect of ammonium ion on the sulfidation flotation of malachite was investigated using microflotation test, inductively coupled plasma (ICP) analysis, zeta potential measurements, and scanning electron microscope analysis (SEM). The results of microflotation test show that the addition of sodium sulfide and ammonium sulfate resulted in better sulfidation than the addition of sodium sulfide alone. The ...

  19. Fuel conditioning facility electrorefiner cadmium vapor trap operation

    International Nuclear Information System (INIS)

    Vaden, D. E.

    1998-01-01

    Processing sodium-bonded spent nuclear fuel at the Fuel Conditioning Facility at Argonne National Laboratory-West involves an electrometallurgical process employing a molten LiCl-KCl salt covering a pool of molten cadmium. Previous research has shown that the cadmium dissolves in the salt as a gas, diffuses through the salt layer and vaporizes at the salt surface. This cadmium vapor condenses on cool surfaces, causing equipment operation and handling problems. Using a cadmium vapor trap to condense the cadmium vapors and reflux them back to the electrorefiner has mitigated equipment problems and improved electrorefiner operations

  20. Effect of cadmium on myocardial contractility and calcium fluxes

    International Nuclear Information System (INIS)

    Pilati, C.F.

    1979-01-01

    The effect of cadmium on myocardial mechanical performance and calcium fluxes was studied in kitten isometric papillary muscles and in isovolumic Langendorff-perfused rabbit hearts. Therefore, it is concluded that cadmium-induced decreases in contractility are not primarily the result of cadmium interference with ATP metabolic processes. Furthermore, these results imply that cadmium causes no structural alterations of the contractile proteins. These data suggest that cadmium may be competing with the calcium needed for excitation-contraction coupling. During experiments using radioisotopic calcium, a statistically significant cellular influx of calcium was observed following the onset of 100 μM Cd ++ perfusion of isolated, Langendorff-prepared rabbit hearts

  1. Quantum Logic and Quantum Reconstruction

    OpenAIRE

    Stairs, Allen

    2015-01-01

    Quantum logic understood as a reconstruction program had real successes and genuine limitations. This paper offers a synopsis of both and suggests a way of seeing quantum logic in a larger, still thriving context.

  2. Quantum dynamics of quantum bits

    International Nuclear Information System (INIS)

    Nguyen, Bich Ha

    2011-01-01

    The theory of coherent oscillations of the matrix elements of the density matrix of the two-state system as a quantum bit is presented. Different calculation methods are elaborated in the case of a free quantum bit. Then the most appropriate methods are applied to the study of the density matrices of the quantum bits interacting with a classical pumping radiation field as well as with the quantum electromagnetic field in a single-mode microcavity. The theory of decoherence of a quantum bit in Markovian approximation is presented. The decoherence of a quantum bit interacting with monoenergetic photons in a microcavity is also discussed. The content of the present work can be considered as an introduction to the study of the quantum dynamics of quantum bits. (review)

  3. Quantum frames

    Science.gov (United States)

    Brown, Matthew J.

    2014-02-01

    The framework of quantum frames can help unravel some of the interpretive difficulties i the foundation of quantum mechanics. In this paper, I begin by tracing the origins of this concept in Bohr's discussion of quantum theory and his theory of complementarity. Engaging with various interpreters and followers of Bohr, I argue that the correct account of quantum frames must be extended beyond literal space-time reference frames to frames defined by relations between a quantum system and the exosystem or external physical frame, of which measurement contexts are a particularly important example. This approach provides superior solutions to key EPR-type measurement and locality paradoxes.

  4. Quantum Darwinism

    Science.gov (United States)

    Zurek, Wojciech Hubert

    2009-03-01

    Quantum Darwinism describes the proliferation, in the environment, of multiple records of selected states of a quantum system. It explains how the quantum fragility of a state of a single quantum system can lead to the classical robustness of states in their correlated multitude; shows how effective `wave-packet collapse' arises as a result of the proliferation throughout the environment of imprints of the state of the system; and provides a framework for the derivation of Born's rule, which relates the probabilities of detecting states to their amplitudes. Taken together, these three advances mark considerable progress towards settling the quantum measurement problem.

  5. Instrument for Airborne Measurement of Carbonyl Sulfide, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Southwest Sciences proposes to develop small, low power instrumentation for the real-time direct measurement of carbonyl sulfide (OCS) in the atmosphere, especially...

  6. New sulfide catalysts for the hydroliquefaction of coal

    NARCIS (Netherlands)

    Vissers, J.P.R.; Oers, van E.M.; Beer, de V.H.J.; Prins, R.

    1987-01-01

    Possibilities for the preparation of new metal sulfide catalyst systems based on carbon carriers having favourable textural and surface properties have been explored, and attention has been given to the characterization (structure) and evaluation (hydrosulfurization activity) of these catalysts. Two

  7. Formation of Copper Sulfide Precipitate in Solid Iron

    Science.gov (United States)

    Urata, Kentaro; Kobayashi, Yoshinao

    The growth rate of copper sulfide precipitates has been measured in low carbon steel samples such as Fe-0.3mass%Cu-0.03mass%S-0.1mass%C and Fe-0.1mass%Cu-0.01mass%S- 0.1mass%C. Heat-treatment of the samples was conducted at 1273, 1423 and 1573 K for 100 s - 14.4 ks for precipitation of copper sulfides and then the samples were observed by a scanning electron microscope and a transmission electron microscope to measure the diameter of copper sulfides precipitated in the samples. The growth rate of copper sulfide has been found to be well described by the Ostwald growth model, as follows: R\

  8. Optimization of biological sulfide removal in a CSTR bioreactor.

    Science.gov (United States)

    Roosta, Aliakbar; Jahanmiri, Abdolhossein; Mowla, Dariush; Niazi, Ali; Sotoodeh, Hamidreza

    2012-08-01

    In this study, biological sulfide removal from natural gas in a continuous bioreactor is investigated for estimation of the optimal operational parameters. According to the carried out reactions, sulfide can be converted to elemental sulfur, sulfate, thiosulfate, and polysulfide, of which elemental sulfur is the desired product. A mathematical model is developed and was used for investigation of the effect of various parameters on elemental sulfur selectivity. The results of the simulation show that elemental sulfur selectivity is a function of dissolved oxygen, sulfide load, pH, and concentration of bacteria. Optimal parameter values are calculated for maximum elemental sulfur selectivity by using genetic algorithm as an adaptive heuristic search. In the optimal conditions, 87.76% of sulfide loaded to the bioreactor is converted to elemental sulfur.

  9. Effects of cadmium electrode properties on nickel-cadmium cell performance

    International Nuclear Information System (INIS)

    Zimmerman, A.H.

    1986-01-01

    Tests have been conducted on a number of nickel-cadmium cells that have exhibited a variety of performance problems, ranging from high voltages and pressures during overcharge to low capacity. The performance problems that have been specifically linked to the cadmium electrode are primarily related to two areas, poor sinter and the buildup of excessive pressure during overcharge. A number of specific nickel-cadmium cell and cadmium electrode characterists have been studied in this work to determine what the effects of poor sinter are, and to determine what factors are important in causing excessive pressures during overcharge in cells that otherwise appear normal. Several of the tests appear suitable for screening cells and electrodes for such problems

  10. Effects of Different Dietary Cadmium Levels on Growth and Tissue Cadmium Content in Juvenile Parrotfish,

    Directory of Open Access Journals (Sweden)

    Okorie E. Okorie

    2014-01-01

    Full Text Available 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.

  11. Quantum dots

    International Nuclear Information System (INIS)

    Kouwenhoven, L.; Marcus, C.

    1998-01-01

    Quantum dots are man-made ''droplets'' of charge that can contain anything from a single electron to a collection of several thousand. Their typical dimensions range from nanometres to a few microns, and their size, shape and interactions can be precisely controlled through the use of advanced nanofabrication technology. The physics of quantum dots shows many parallels with the behaviour of naturally occurring quantum systems in atomic and nuclear physics. Indeed, quantum dots exemplify an important trend in condensed-matter physics in which researchers study man-made objects rather than real atoms or nuclei. As in an atom, the energy levels in a quantum dot become quantized due to the confinement of electrons. With quantum dots, however, an experimentalist can scan through the entire periodic table by simply changing a voltage. In this article the authors describe how quantum dots make it possible to explore new physics in regimes that cannot otherwise be accessed in the laboratory. (UK)

  12. INVESTIGATIONS ON BIOCHEMICAL PURIFICATION OF GROUND WATER FROM HYDROGEN SULFIDE

    Directory of Open Access Journals (Sweden)

    Yu. P. Sedlukho

    2015-01-01

    Full Text Available The paper considers problems and features of biochemical removal of hydrogen sulfide from ground water. The analysis of existing methods for purification of ground water from hydrogen sulfide has been given in the paper. The paper has established shortcomings of physical and chemical purification of ground water. While using aeration methods for removal of hydrogen sulfide formation of colloidal sulfur that gives muddiness and opalescence to water occurs due to partial chemical air oxidation. In addition to this violation of sulfide-carbonate equilibrium taking place in the process of aeration due to desorption of H2S and CO2, often leads to clogging of degasifier nozzles with formed CaCO3 that causes serious operational problems. Chemical methods require relatively large flow of complex reagent facilities, storage facilities and transportation costs.In terms of hydrogen sulfide ground water purification the greatest interest is given to the biochemical method. Factors deterring widespread application of the biochemical method is its insufficient previous investigation and necessity to execute special research in order to determine optimal process parameters while purifying groundwater of a particular water supply source. Biochemical methods for oxidation of sulfur compounds are based on natural biological processes that ensure natural sulfur cycle. S. Vinogradsky has established a two-stage mechanism for oxidation of hydrogen sulfide with sulfur bacteria (Beggiatoa. The first stage presupposes oxidation of hydrogen sulphide to elemental sulfur which is accumulating in the cytoplasm in the form of globules. During the second stage sulfur bacteria begin to oxidize intracellular sulfur to sulfuric acid due to shortage of hydrogen sulfide.The paper provides the results of technological tests of large-scale pilot plants for biochemical purification of groundwater from hydrogen sulfide in semi-industrial conditions. Dependences of water quality

  13. Remediation of cadmium by Indian mustard (Brassica juncea L.) from cadmium contaminated soil: a phytoextraction study

    OpenAIRE

    Rajeev Kumar Bhadkariya; VK Jain; GPS Chak; SK Gupta

    2014-01-01

    Cadmium is a toxic metal for living organisms and an environmental contaminant. Soils in many parts of the world are slightly too moderately contaminated by Cd due to long term use and disposal of Cd-contaminated wastes. Cost effective technologies are needed to remove cadmium from the contaminated sites. Soil phytoextraction is engineering based, low cost and socially accepted developing technology that uses plants to clean up contaminants in soils. This technology can be adopted as a remedi...

  14. Cadmium in Salix. A study to show the capacity of Salix to remove cadmium from farmland

    International Nuclear Information System (INIS)

    Oestman, G.

    1994-01-01

    The aim of this report has been to show the ability of Salix to take up cadmium and how the uptake varies between different types of soil. The information that the results are based on has been obtained from analyses of soil and Salix. The samples were taken at five sites in the district around Lake Maelaren. Two or three stands were taken at each place. The factors studied were the pH, the organic matter content, and the concentration of cadmium in the soil. Salix has a good ability, relative to other crops, to remove cadmium from arable land. The cadmium uptake is 35 times higher with Salix than with straw or energy grass. Salix uptake of cadmium varies between 3 and 14% of the cadmium content in the soil that is accessible to plants. The present annual increase of cadmium in arable land is 1 g/ha, whereas the removal in a Salix plantation is 21 g Cd/ha, yr at an annual growth of 10 tonnes DM. If the Cd uptake is the same each year, then a total of 420 g Cd/ha is removed when Salix is grown over a 20-year period. This is a very large part of the topsoil's total cadmium content, which is 550 g/ha on average in Sweden. The investigation reveals no clear relationship between the Cd concentration in Salix and the concentration of Cd in the soil, the organic matter content or the pH. 22 refs, 4 figs, 2 tabs

  15. Murine strain differences and the effects of zinc on cadmium concentrations in tissues after acute cadmium exposure

    Energy Technology Data Exchange (ETDEWEB)

    King, L.M. [ARS USDA, Germplasm and Gamete Physiology Lab., Beltsville, MD (United States); Anderson, M.B. [Dept. of Anatomy, Tulane Univ. School of Medicine, New Orleans, LA (United States); Sikka, S.C. [Dept. of Urology, Tulane Univ. School of Medicine, New Orleans, LA (United States); George, W.J. [Dept. of Pharmacology, Tulane Univ. School of Medicine, New Orleans, LA (United States)

    1998-10-01

    The role of strain differences in cadmium tissue distribution was studied using sensitive (129/J) and resistant (A/J) mice. These murine strains have previously been shown to differ in their susceptibility to cadmium-induced testicular toxicity. Cadmium concentration was measured in testis, epididymis, seminal vesicle, liver, and kidney at 24 h after cadmium chloride exposure (4, 10, and 20 {mu}mol/kg CdCl{sub 2}). The 129/J mice exhibited a significant increase in cadmium concentration in testis, epididymis, and seminal vesicle at all cadmium doses used, compared to A/J mice. However, cadmium concentrations in liver and kidney were not different between the strains, at any dose, indicating that cadmium uptake is similar in these organs at 24 h. These murine strains demonstrate similar hepatic and renal cadmium uptake but significantly different cadmium accumulation in the reproductive organs at 24 h. The mechanism of the protective effect of zinc on cadmium toxicity was studied by assessing the impact of zinc acetate (ZnAc) treatment on cadmium concentrations in 129/J mice after 24 h. Zinc pretreatment (250 {mu}mol/kg ZnAc), given 24 h prior to 20 {mu}mol/kg CdCl{sub 2} administration, significantly decreased the amount of cadmium in the testis, epididymis, and seminal vesicle of 129/J mice, and significantly increased the cadmium content of the liver after 24 h. Cadmium levels in the kidney were unaffected at this time. Zinc pretreatment also prevented the cadmium-induced decrease in testicular sperm concentration and epididymal sperm motility seen in 129/J mice. These findings suggest that the differences in the two murine strains may be attributed partly to the differential accumulation of cadmium in murine gonads. This may be caused by strain differences in the specificity of cadmium transport mechanisms. The protective role of zinc in cadmium-induced testicular toxicity in the sensitive strain may be due to an interference in the cadmium uptake by susceptible

  16. Quantum information. Teleporation - cryptography - quantum computer

    International Nuclear Information System (INIS)

    Breuer, Reinhard

    2010-01-01

    The following topics are dealt with: Reality in the test house, quantum teleportation, 100 years of quantum theory, the reality of quanta, interactionless quantum measurement, rules for quantum computers, quantum computers with ions, spintronics with diamond, the limits of the quantum computers, a view into the future of quantum optics. (HSI)

  17. Hydrogen sulfide oxidation without oxygen - oxidation products and pathways

    International Nuclear Information System (INIS)

    Fossing, H.

    1992-01-01

    Hydrogen sulfide oxidation was studied in anoxic marine sediments-both in undisturbed sediment cores and in sediment slurries. The turn over of hydrogen sulfide was followed using 35 S-radiolabeled hydrogen sulfide which was injected into the sediment. However, isotope exchange reactions between the reduced sulfur compounds, in particular between elemental sulfur and hydrogen sulfide, influenced on the specific radioactivity of these pools. It was, therefore, not possible to measure the turn over rates of the reduced sulfur pools by the radiotracer technique but merely to use the radioisotope to demonstrate some of the oxidation products. Thiosulfate was one important intermediate in the anoxic oxidation of hydrogen sulfide and was continuously turned over by reduction, oxidation and disproportionation. The author discusses the importance of isotope exchange and also presents the results from experiments in which both 35 S-radiolabeled elemental sulfur, radiolabeled hydrogen sulfide and radiolabeled thiosulfate were used to study the intermediates in the oxidative pathways of the sulfur cycle

  18. Bioavailability and stability of mercury sulfide in Armuchee (USA) soil

    International Nuclear Information System (INIS)

    Han, Fengxiang; Shiyab, Safwan; Su, Yi; Monts, David L.; Waggoner, Charles A.; Matta, Frank B.

    2007-01-01

    Because of the adverse effects of elemental mercury and mercury compounds upon human health, the U.S. Department of Energy (DOE) is engaged in an on-going effort to monitor and remediate mercury-contaminated DOE sites. In order to more cost effectively implement those extensive remediation efforts, it is necessary to obtain an improved understanding of the role that mercury and mercury compounds play in the ecosystem. We have conducted pilot scale experiments to study the bioavailability of mercury sulfide in an Armuchee (eastern US ) soil. The effects of plants and incubation time on chemical stability and bioavailability of HgS under simulated conditions of the ecosystem have been examined, as has the dynamics of the dissolution of mercury sulfide by various extractants. The results show that mercury sulfide in contaminated Armuchee soil was still to some extent bioavailable to plants. After planting, soil mercury sulfide is more easily dissolved by both 4 M and 12 M nitric acid than pure mercury sulfide reagent. Dissolution kinetics of soil mercury sulfide and pure chemical reagent by nitric acid are different. Mercury release by EDTA from HgS-contaminated soil increased with time of reaction and soil mercury level. Chelating chemicals increase the solubility and bioavailability of mercury in HgS-contaminated soil. (authors)

  19. Laser cleaning of sulfide scale on compressor impeller blade

    International Nuclear Information System (INIS)

    Tang, Q.H.; Zhou, D.; Wang, Y.L.; Liu, G.F.

    2015-01-01

    Highlights: • The effects of sulfide layers and fluence values on the mechanism of laser cleaning were experimentally established. • The specimen surface with sulfide scale becomes slightly smoother than that before laser cleaning. • The mechanism of laser cleaning the sulfide scale of stainless steel is spallation without oxidization. • It would avoid chemical waste and dust pollution using a fiber laser instead of using nitric acids or sandblasting. - Abstract: Sulfide scale on the surface of a compressor impeller blade can considerably reduce the impeller performance and its service life. To prepare for subsequent remanufacturing, such as plasma spraying, it needs to be removed completely. In the corrosion process on an FV(520)B stainless steel, sulfide scale is divided into two layers because of different outward diffusion rates of Cr, Ni and Fe. In this paper, the cleaning threshold values of the upper and inner layers and the damage threshold value of the substrate were investigated using a pulsed fiber laser. To obtain experimental evidence, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and 3D surface profilometry were employed to investigate the two kinds of sulfide layers on specimens before, during, and after laser cleaning.

  20. Quantum symmetry in quantum theory

    International Nuclear Information System (INIS)

    Schomerus, V.

    1993-02-01

    Symmetry concepts have always been of great importance for physical problems like explicit calculations, classification or model building. More recently, new 'quantum symmetries' ((quasi) quantum groups) attracted much interest in quantum theory. It is shown that all these quantum symmetries permit a conventional formulation as symmetry in quantum mechanics. Symmetry transformations can act on the Hilbert space H of physical states such that the ground state is invariant and field operators transform covariantly. Models show that one must allow for 'truncation' in the tensor product of representations of a quantum symmetry. This means that the dimension of the tensor product of two representations of dimension σ 1 and σ 2 may be strictly smaller than σ 1 σ 2 . Consistency of the transformation law of field operators local braid relations leads us to expect, that (weak) quasi quantum groups are the most general symmetries in local quantum theory. The elements of the R-matrix which appears in these local braid relations turn out to be operators on H in general. It will be explained in detail how examples of field algebras with weak quasi quantum group symmetry can be obtained. Given a set of observable field with a finite number of superselection sectors, a quantum symmetry together with a complete set of covariant field operators which obey local braid relations are constructed. A covariant transformation law for adjoint fields is not automatic but will follow when the existence of an appropriate antipode is assumed. At the example of the chiral critical Ising model, non-uniqueness of the quantum symmetry will be demonstrated. Generalized quantum symmetries yield examples of gauge symmetries in non-commutative geometry. Quasi-quantum planes are introduced as the simplest examples of quasi-associative differential geometry. (Weak) quasi quantum groups can act on them by generalized derivations much as quantum groups do in non-commutative (differential-) geometry

  1. Remediation of cadmium by Indian mustard (Brassica juncea L. from cadmium contaminated soil: a phytoextraction study

    Directory of Open Access Journals (Sweden)

    Rajeev Kumar Bhadkariya

    2014-05-01

    Full Text Available Cadmium is a toxic metal for living organisms and an environmental contaminant. Soils in many parts of the world are slightly too moderately contaminated by Cd due to long term use and disposal of Cd-contaminated wastes. Cost effective technologies are needed to remove cadmium from the contaminated sites. Soil phytoextraction is engineering based, low cost and socially accepted developing technology that uses plants to clean up contaminants in soils. This technology can be adopted as a remediation of cadmium from Cd-contaminated soils with the help of Brassica juncea plant. The objective of this work was to evaluate the cadmium (Cd accumulate and the tolerance of Brassica juncea. The Cd accumulates in all parts of plants (roots, stems and leaves. It was found that accumulating efficiency increased with the increase in the concentration of applied cadmium metal solution. Maximum accumulation of cadmium was found in roots than stem and leaves. Phytoextraction coefficient and translocation factor were highest to show the validity of the Brassica juncea species for hyperaccumulation of the Cd metal. These results suggested that Brassica juncea has a high ability to tolerate and accumulate Cd, so it might be a promising plant to be used for phytoextraction of Cd contaminated soil. DOI: http://dx.doi.org/10.3126/ije.v3i2.10533 International Journal of the Environment Vol.3(2 2014: 229-237

  2. Hydrogen sulfide production from subgingival plaque samples.

    Science.gov (United States)

    Basic, A; Dahlén, G

    2015-10-01

    Periodontitis is a polymicrobial anaerobe infection. Little is known about the dysbiotic microbiota and the role of bacterial metabolites in the disease process. It is suggested that the production of certain waste products in the proteolytic metabolism may work as markers for disease severity. Hydrogen sulfide (H2S) is a gas produced by degradation of proteins in the subgingival pocket. It is highly toxic and believed to have pro-inflammatory properties. We aimed to study H2S production from subgingival plaque samples in relation to disease severity in subjects with natural development of the disease, using a colorimetric method based on bismuth precipitation. In remote areas of northern Thailand, adults with poor oral hygiene habits and a natural development of periodontal disease were examined for their oral health status. H2S production was measured with the bismuth method and subgingival plaque samples were analyzed for the presence of 20 bacterial species with the checkerboard DNA-DNA hybridization technique. In total, 43 subjects were examined (age 40-60 years, mean PI 95 ± 6.6%). Fifty-six percent had moderate periodontal breakdown (CAL > 3  7 mm) on at least one site. Parvimonas micra, Filifactor alocis, Porphyromonas endodontalis and Fusobacterium nucleatum were frequently detected. H2S production could not be correlated to periodontal disease severity (PPD or CAL at sampled sites) or to a specific bacterial composition. Site 21 had statistically lower production of H2S (p = 0.02) compared to 16 and 46. Betel nut chewers had statistically significant lower H2S production (p = 0.01) than non-chewers. Rapid detection and estimation of subgingival H2S production capacity was easily and reliably tested by the colorimetric bismuth sulfide precipitation method. H2S may be a valuable clinical marker for degradation of proteins in the subgingival pocket. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Physiological behavior of hydrogen sulfide in rice plant. Part 5. Effect of hydrogen sulfide on respiration of rice roots

    Energy Technology Data Exchange (ETDEWEB)

    Okajima, H; Takagi, S

    1955-01-01

    The inhibitory effects of hydrogen sulfide on the respiration of rice plant roots were investigated using Warburg's manometory technique. Hydrogen sulfide inhibited not only aerobic respiration but anaerobic respiration process of roots. Inhibitory action of hydrogen sulfide and potassium cyanide on the respiration were apparently reversible, but the style of recovery reaction from inhibition was somewhat different in each case. Oxygen consumption of roots was increased by addition of ammonium salts, but the same effects were not recognized by the addition of any other salt examined (except nitrate salts). There was close relationship between respiration of roots and assimilation of nitrogen by roots. The increased oxygen uptake by addition of ammonium salt was also inhibited by hydrogen sulfide. The reactivation of this reaction occurred with the recovery of endogenous respiration of roots. 19 references, 8 figures, 3 tables.

  4. Subcellular localization of cadmium in hyperaccumulator Populus ...

    African Journals Online (AJOL)

    In this study, subcellular localization of cadmium in hyperaccumulator grey poplar (Populus × canescens) was investigated by the transmission electron microscopy (TEM) method. Young Populus × canescens were grown and hydroponic experiments were conducted under four Cd2+ concentrations (10, 30, 50, and 70 μM) ...

  5. Rise time spectroscopy in cadmium telluride detectors

    International Nuclear Information System (INIS)

    Scharager, Claude; Siffert, Paul; Carnet, Bernard; Le Meur, Roger.

    1980-11-01

    By a simultaneous analysis of rise time and pulse amplitude distributions of the signals issued from various cadmium telluride detectors, it is possible to obtain informations about surface and bulk trapping, field distribution within the detectors, as well as charge collection and transport properties. These investigations have been performed on both pure and chlorine doped and materials for various surfaces preparation conditions [fr

  6. Bioavailability of cadmium from linseed and cocoa

    DEFF Research Database (Denmark)

    Hansen, Max; Rasmussen, Rie Romme; Sloth, Jens Jørgen

    2014-01-01

    The exposure of the European population to cadmium from food is high compared with the tolerable weekly intake of 2.5 μg/kg bodyweight set by EFSA in 2009. Only few studies on the bioavailability of cadmium from different food sources has been performed but this information in very important...... for the food authorities in order to give correct advises to the population. The aim of this study was to investigate the bioavailability of cadmium from whole linseed, crushed linseed, cocoa and cadmium chloride in rats. An experiment where 40 rats were divided into 4 groups and a control group and dosed...... be measured in the kidney compared to the calculated total intake was as follows: Control 2.0 %, Crushed linseed 0.9 %, whole linseed, 1.5 %, cocoa 0.7 % and CdCl2 4.6 %. Based on this study it could not be concluded that the bioavailability in rats form whole linseed is lower that for crushed linseed...

  7. Cadmium versus phosphate in the world ocean

    NARCIS (Netherlands)

    Baar, Hein J.W. de; Saager, Paul M.; Nolting, Rob F.; Meer, Jaap van der

    1994-01-01

    Cadmium (Cd) is one of the best studied trace metals in seawater and at individual stations exhibits a more or less linear relation with phosphate. The compilation of all data from all oceans taken from over 30 different published sources into one global dataset yields only a broad scatterplot of Cd

  8. PRELIMINARY ASSESSMENT OF CADMIUM MOBILITY IN ...

    African Journals Online (AJOL)

    Preferred Customer

    ABSTRACT. Cadmium is a toxic metal often found with a strong enrichment factor in coastal sediments. ... into the food chain, which could result in a wide variety of adverse effects in animals and ... Sampling scheme and sample conservation ..... of Cd with Fe and Mn oxides has also been reported in others studies [38, 39].

  9. Combustion synthesis of cadmium sulphide nanomaterials

    Indian Academy of Sciences (India)

    Anion-doped cadmium sulphide nanomaterials have been synthesized by using combustionmethod at normal atmospheric conditions. Oxidant/fuel ratios have been optimized in order to obtain CdS with best characteristics. Formation of CdS and size of crystallite were identified by X-ray diffraction and confirmed by ...

  10. Phytochelatin and cadmium accumulation in wheat.

    NARCIS (Netherlands)

    Stolt, J.P.; Sneller, F.E.C.; Bryngelson, T.; Lundborg, T.; Schat, H.

    2003-01-01

    Cadmium (Cd) is a nonessential heavy metal that can be harmful at low concentrations in organisms. Therefore, it is necessary to decrease Cd accumulation in the grains of wheats aimed for human consumption. In response to Cd, higher plants synthesize sulphur-rich peptides, phytochelatins (PCs).

  11. New process to discharge negative cadmium electrodes for Ni/Cd batteries

    International Nuclear Information System (INIS)

    Stiker, B.; Vignaud, R.

    1984-01-01

    The new process relates to the chemical oxidation (whether partial or total) of cadmium metal negative electrodes, as used in alkaline nickel-cadmium or silver-cadmium batteries. This process concerns all cadmium electrodes but more particularly the electrodeposited cadmium electrode developed by the company LES PILES WONDER and described in this publication

  12. Thiosulfate leaching of gold from sulfide wastes

    Energy Technology Data Exchange (ETDEWEB)

    Block-Bolten, A.; Torma, A.E.

    1986-07-01

    The kinetics of gold extraction from lead-zinc sulfide flotation tailings by thiosulfate leachants has been investigated. The order of reaction as well as the overall reaction rate constant were, with respect to thiosulfate concentration, calculated to be n=0.75 and k=1.05 x 10/sup -6/ mol/sup 1/4/ dm/sup 5/4/ min/sup -1/. The apparent activation energy was found to be ..delta..E/sub a/=48.53 kJ and the frequency factor A=7.5 x 10/sup 2/ mol dm/sup -3/ min/sup -1/. This activation energy value suggests chemical control of the reaction mechanism. Optimum leach temperature of 50/sup 0/C was established. Gold extractions as high as 99% have been realized in two step countercurrent leachings. Change in pH throughout the leaching process was found to be an excellent indicator for the progress of the extraction. A preliminary economic evaluation of the process is given.

  13. Luminescent sulfides of monovalent and trivalent cations

    International Nuclear Information System (INIS)

    1975-01-01

    The invention discloses a family of luminescent materials or phosphors having a rhombohedral crystal structure and consisting essentially of a mixed host sulfide of at least one monovalent host cation and at least one trivalent host cation, and containing, for each mole of phosphor, 0.0005 to 0.05 mole of at least one activating cation. The monovalent host cations may be Na, K or Rb and Cs. The trivalent host cations may be Gd, La, Lu, Sc and Y. The activating cations may be one or more of trivalent As, Bi, Ce, Dy, Er, Pr, Sb, Sm, Tb and Tm; divalent Lu, Mn, Pb and Sn; and monovalent Ag, Cu and Tl. The novel phosphors may be used in devices to convert electron-beam, ultraviolet or x-ray energy to light in the visible spectrum. Such energy conversion can be employed for example in fluoroscopic screens, and in viewing screens of cathode-ray tubes and other electron tubes

  14. Comparison of Carbon XANES Spectra from an Iron Sulfide from Comet Wild 2 with an Iron Sulfide Interplanetary Dust Particle

    Science.gov (United States)

    Wirick, S.; Flynn, G. J.; Keller, L. P.; Sanford, S. A.; Zolensky, M. E.; Messenger, Nakamura K.; Jacobsen, C.

    2008-01-01

    Among one of the first particles removed from the aerogel collector from the Stardust sample return mission was an approx. 5 micron sized iron sulfide. The majority of the spectra from 5 different sections of this particle suggests the presence of aliphatic compounds. Due to the heat of capture in the aerogel we initially assumed these aliphatic compounds were not cometary but after comparing these results to a heated iron sulfide interplanetary dust particle (IDP) we believe our initial interpretation of these spectra was not correct. It has been suggested that ice coating on iron sulfides leads to aqueous alteration in IDP clusters which can then lead to the formation of complex organic compounds from unprocessed organics in the IDPs similar to unprocessed organics found in comets [1]. Iron sulfides have been demonstrated to not only transform halogenated aliphatic hydrocarbons but also enhance the bonding of rubber to steel [2,3]. Bromfield and Coville (1997) demonstrated using Xray photoelectron spectroscopy that "the surface enhancement of segregated sulfur to the surface of sulfided precipitated iron catalysts facilitates the formation of a low-dimensional structure of extraordinary properties" [4]. It may be that the iron sulfide acts in some way to protect aliphatic compounds from alteration due to heat.

  15. Quantum games as quantum types

    Science.gov (United States)

    Delbecque, Yannick

    In this thesis, we present a new model for higher-order quantum programming languages. The proposed model is an adaptation of the probabilistic game semantics developed by Danos and Harmer [DH02]: we expand it with quantum strategies which enable one to represent quantum states and quantum operations. Some of the basic properties of these strategies are established and then used to construct denotational semantics for three quantum programming languages. The first of these languages is a formalisation of the measurement calculus proposed by Danos et al. [DKP07]. The other two are new: they are higher-order quantum programming languages. Previous attempts to define a denotational semantics for higher-order quantum programming languages have failed. We identify some of the key reasons for this and base the design of our higher-order languages on these observations. The game semantics proposed in this thesis is the first denotational semantics for a lambda-calculus equipped with quantum types and with extra operations which allow one to program quantum algorithms. The results presented validate the two different approaches used in the design of these two new higher-order languages: a first one where quantum states are used through references and a second one where they are introduced as constants in the language. The quantum strategies presented in this thesis allow one to understand the constraints that must be imposed on quantum type systems with higher-order types. The most significant constraint is the fact that abstraction over part of the tensor product of many unknown quantum states must not be allowed. Quantum strategies are a new mathematical model which describes the interaction between classical and quantum data using system-environment dialogues. The interactions between the different parts of a quantum system are described using the rich structure generated by composition of strategies. This approach has enough generality to be put in relation with other

  16. Cadmium phytoextraction potential of different Alyssum species

    International Nuclear Information System (INIS)

    Barzanti, R.; Colzi, I.; Arnetoli, M.; Gallo, A.; Pignattelli, S.; Gabbrielli, R.; Gonnelli, C.

    2011-01-01

    Highlights: ► The possibility of using serpentine plants for phytoextraction of Cd was investigated. ► Variation in Cd tolerance, accumulation and translocation in three Alyssum plants with different phenotypes were found. ► Alyssum montanum showed higher Cd tolerance and accumulation than the Ni hyperaccumulator Alyssum bertolonii. ► As for the kinetic parameters of the Cd uptake system, A. montanum presented a low apparent K m value. ► The V max values were not significantly different among the plants. - Abstract: This work was planned for providing useful information about the possibility of using serpentine adapted plants for phytoextraction of cadmium, element scarcely represented in such metalliferous environment. To this aim, we investigated variation in cadmium tolerance, accumulation and translocation in three Alyssum plants with different phenotypes: Alyssum bertolonii, that is a serpentine endemic nickel hyperaccumulator, and two populations of Alyssum montanum, one adapted and one not adapted to serpentine soils. Plants were hydroponically cultivated in presence of increasing concentrations of CdSO 4 for two weeks. For the metal concentration used in the experiments, the three different Alyssum populations showed variation in cadmium tolerance, accumulation and content. The serpentine adapted population of A. montanum showed statistically higher cadmium tolerance and accumulation than A. bertolonii and the population of A. montanum not adapted to serpentine soil thus deserving to be investigated for phytoextraction purposes. Furthermore, as for the kinetic parameters of the cadmium uptake system, A. montanum serpentine population presented a low apparent K m value, suggesting a high affinity for this metal of its uptake system, whereas the V max values were not significantly different among the plants. Present data revealed metallicolous plants are also suitable for the phytoremediation of metals underrepresented in the environment of their

  17. Cadmium phytoextraction potential of different Alyssum species

    Energy Technology Data Exchange (ETDEWEB)

    Barzanti, R., E-mail: rbarzanti@supereva.it [Department of Evolutionary Biology, Universita di Firenze, via Micheli 1, 50121 Firenze (Italy); Colzi, I., E-mail: ilariacolzi@hotmail.it [Department of Evolutionary Biology, Universita di Firenze, via Micheli 1, 50121 Firenze (Italy); Arnetoli, M., E-mail: miluscia@gmail.com [Department of Evolutionary Biology, Universita di Firenze, via Micheli 1, 50121 Firenze (Italy); Gallo, A., E-mail: galloalessia@hotmail.com [Department of Evolutionary Biology, Universita di Firenze, via Micheli 1, 50121 Firenze (Italy); Pignattelli, S., E-mail: sara.pignattelli@gmail.com [Department of Evolutionary Biology, Universita di Firenze, via Micheli 1, 50121 Firenze (Italy); Gabbrielli, R., E-mail: gabbrielli@unifi.it [Department of Evolutionary Biology, Universita di Firenze, via Micheli 1, 50121 Firenze (Italy); Gonnelli, C., E-mail: cristina.gonnelli@unifi.it [Department of Evolutionary Biology, Universita di Firenze, via Micheli 1, 50121 Firenze (Italy)

    2011-11-30

    Highlights: Black-Right-Pointing-Pointer The possibility of using serpentine plants for phytoextraction of Cd was investigated. Black-Right-Pointing-Pointer Variation in Cd tolerance, accumulation and translocation in three Alyssum plants with different phenotypes were found. Black-Right-Pointing-Pointer Alyssum montanum showed higher Cd tolerance and accumulation than the Ni hyperaccumulator Alyssum bertolonii. Black-Right-Pointing-Pointer As for the kinetic parameters of the Cd uptake system, A. montanum presented a low apparent K{sub m} value. Black-Right-Pointing-Pointer The V{sub max} values were not significantly different among the plants. - Abstract: This work was planned for providing useful information about the possibility of using serpentine adapted plants for phytoextraction of cadmium, element scarcely represented in such metalliferous environment. To this aim, we investigated variation in cadmium tolerance, accumulation and translocation in three Alyssum plants with different phenotypes: Alyssum bertolonii, that is a serpentine endemic nickel hyperaccumulator, and two populations of Alyssum montanum, one adapted and one not adapted to serpentine soils. Plants were hydroponically cultivated in presence of increasing concentrations of CdSO{sub 4} for two weeks. For the metal concentration used in the experiments, the three different Alyssum populations showed variation in cadmium tolerance, accumulation and content. The serpentine adapted population of A. montanum showed statistically higher cadmium tolerance and accumulation than A. bertolonii and the population of A. montanum not adapted to serpentine soil thus deserving to be investigated for phytoextraction purposes. Furthermore, as for the kinetic parameters of the cadmium uptake system, A. montanum serpentine population presented a low apparent K{sub m} value, suggesting a high affinity for this metal of its uptake system, whereas the V{sub max} values were not significantly different among the

  18. Cadmium-induced fetal toxicity in the rat

    International Nuclear Information System (INIS)

    Levin, A.A.

    1980-01-01

    Cadmium, a heavy metal environment contaminant, induces fetal death and placental necrosis in the Wistar rat. This study investigated fetal, maternal, and placental responses to cadmium intoxication. Subcutaneous injection of CdCl 2 to dams on day 18 of pregnancy produced a high incidence of fetal death (75%) and placental necrosis. Death in the fetus was produced despite limited fetal accumulations of cadmium. Distribution studies using 109 Cd-labeled CdCl 2 demonstrated that less than 0.1% of the injected dose was associated with the fetus. To determine if fetuses were sensitive to these low levels of cadmium, direct injections of CdCl 2 into fetuses were performed in utero. Direct injections produced fetal accumulations 8-fold greater than those following maternal injections. The 8-fold greater fetal accumulations following direct injection were associated with only a 12% fetal mortality compared to the 75% mortality following maternal injections. The data indicated that the fetal toxicity of cadmium following maternal injections was not the result of direct effects of cadmium on the fetus. In conclusion, cadmium-induced fetal death was not the result of direct effects of cadmium on the fetus but may have been induced by placental cellular injury resulting from high accumulations of cadmium in the placenta. A vascular response to placental injury, leading to decreased utero-placental bood flow and cadmium-induced alterations in trophoblastic function, resulted in fetal death

  19. Accumulation of cadmium in livers and kidneys in Greenlanders

    International Nuclear Information System (INIS)

    Johansen, Poul; Mulvad, Gert; Pedersen, Henning Sloth; Hansen, Jens C.; Riget, Frank

    2006-01-01

    In the Arctic, the traditional diet exposes its people to a very high intake of cadmium because it is highly concentrated in the liver and kidneys of commonly eaten marine mammals. In one study in Greenland, the cadmium intake was estimated to 182 μg/day/person in the fall and 346 in the spring. To determine whether the cadmium is accumulated in humans, we analyzed autopsy samples of liver and kidneys from 95 ethnic Greenlanders (aged 19-89) who died from a wide range of causes. The cadmium concentration in liver (overall mean 1.97 μg/g wet wt) appeared to be unrelated to any particular age group, whereas the concentrations in the kidneys peaked in Greenlanders between 40 and 50 years of age (peak concentration 22.3 μg/g wet wt). Despite the high cadmium levels in the typical Greenlander diet, we found that the cadmium concentrations in livers and kidneys were comparable to those reported from Denmark, Sweden, Australia and Great Britain. Furthermore, even though the mean cadmium intake from the diet was estimated to be 13-25 times higher in Greenlanders than in Danes, we found similar cadmium levels in the kidneys of both. Seal livers and kidneys are the main source of cadmium in the diet of Greenlanders, but these tissues are not eaten in Denmark. Thus, our results suggest that the accumulation of cadmium from Greenlander's marine diet is very low

  20. Accumulation of cadmium in livers and kidneys in Greenlanders

    Energy Technology Data Exchange (ETDEWEB)

    Johansen, Poul [National Environmental Research Institute, Frederiksborgvej 399, DK-4000 Roskilde (Denmark)]. E-mail: poj@dmu.dk; Mulvad, Gert [Primary Health Care Center, DK-3900 Nuuk, Greenland (Denmark); Centre for Arctic Environmental Medicine, University of Aarhus, Universitetsparken, DK-8000 Aarhus C (Denmark); Pedersen, Henning Sloth [Primary Health Care Center, DK-3900 Nuuk, Greenland (Denmark); Centre for Arctic Environmental Medicine, University of Aarhus, Universitetsparken, DK-8000 Aarhus C (Denmark); Hansen, Jens C. [Centre for Arctic Environmental Medicine, University of Aarhus, Universitetsparken, DK-8000 Aarhus C (Denmark); Riget, Frank [National Environmental Research Institute, Frederiksborgvej 399, DK-4000 Roskilde (Denmark)

    2006-12-15

    In the Arctic, the traditional diet exposes its people to a very high intake of cadmium because it is highly concentrated in the liver and kidneys of commonly eaten marine mammals. In one study in Greenland, the cadmium intake was estimated to 182 {mu}g/day/person in the fall and 346 in the spring. To determine whether the cadmium is accumulated in humans, we analyzed autopsy samples of liver and kidneys from 95 ethnic Greenlanders (aged 19-89) who died from a wide range of causes. The cadmium concentration in liver (overall mean 1.97 {mu}g/g wet wt) appeared to be unrelated to any particular age group, whereas the concentrations in the kidneys peaked in Greenlanders between 40 and 50 years of age (peak concentration 22.3 {mu}g/g wet wt). Despite the high cadmium levels in the typical Greenlander diet, we found that the cadmium concentrations in livers and kidneys were comparable to those reported from Denmark, Sweden, Australia and Great Britain. Furthermore, even though the mean cadmium intake from the diet was estimated to be 13-25 times higher in Greenlanders than in Danes, we found similar cadmium levels in the kidneys of both. Seal livers and kidneys are the main source of cadmium in the diet of Greenlanders, but these tissues are not eaten in Denmark. Thus, our results suggest that the accumulation of cadmium from Greenlander's marine diet is very low.