Search

Major source for human exposure to cadmium nitrate (Cd(NO3)2) is from smoking and occupational hazard. Cd(NO3)2-induced neurotoxicity and related mechanism in neurons are still unknown. Here, Cd(NO3)2induced cytotoxicity in a concentration- and time-dependent manners on Neuro-2A (N2A) neurons. Genotoxicity, which included micronucleus formation and DNA damage, and caspases, which included caspase-3, -8 and -9, activities were increased by Cd(NO3)2in a concentration-dependent manner. The concentration trends of Cd(NO3)2: 1, 3 and 10 μM, were similar in the significant induction of cytotoxicity and genotoxicity and the up-regulation of the activities of caspase-3, -8, -9. In conclusion, cytotoxicity and genotoxicity were induced by Cd(NO3)2via caspases activities on neurons. [ABSTRACT FROM AUTHOR]

Molecular dynamics (MD) simulation of [Cd(II)] along with nitrate ions and water in dodecane was carried out for different nitric acid concentrations. The extraction process using N,N,N’,N’-tetraoctyldiglycolamide (TODGA) and tributyl phosphate (TBP), in biphasic systems, is also simulated at three nitric acid concentrations. In the TBP-based system, the formation of a third phase was observed at 3 M nitric acid concentration. Cd(II) ions form reverse micelles-like clusters with TODGA as an extractant in dodecane. The mass percentage of TODGA in these clusters decreases with increase in the acid concentration while increasing the size of the aggregates at the same time. [ABSTRACT FROM PUBLISHER]

With the view to creating novel fluorescent materials, an unusual zinc porphyrin ZnTCPP(EtOH)2(TCPP =meso-tetra(4-carboxyphenyl)porphyrin; EtOH = ethanol) has been designed, synthesized, and spectroscopically characterized. Its crystal structure was characterized by a single-crystal X-ray diffraction method. The title complex exhibits an isolated structure in which the zinc metal coordinates to four Nporphyrinatoms and two OEtOHatoms. The fluorescent study reveals that the title complex shows bright red emissions. [ABSTRACT FROM AUTHOR]

This study quantitatively evaluates a waste-to-resource strategy of blending zinc-laden sludge and clay material for low-cost ceramic products. Using ZnO as the simulated zinc-laden sludge to sinter with kaolinite, both zinc aluminate spinel (ZnAl2O4) and willemite (Zn2SiO4) phases were formed during the sintering process. To analyse the details of zinc incorporation reactions,γ-Al2O3and quartz were further used as precursors to observe ZnAl2O4and Zn2SiO4formations. By firing the ZnO mixtures and their corresponding precursors at 750–1350°C for 3 h, the efficiency of zinc transformation was determined through Rietveld refinement analyses of X-ray diffraction data. The results also show different incorporation behaviour for kaolinite and mullite precursors during the formation of ZnAl2O4and Zn2SiO4in the system. In addition, with a competitive formation between ZnAl2O4and Zn2SiO4, the ZnAl2O4spinel phase is predominant at temperatures higher than 1050°C. This study used a prolonged leaching test modified from the US Environmental Protection Agency's toxicity characteristic leaching procedure to evaluate ZnO, ZnAl2O4, and Zn2SiO4product phases. The zinc concentrations in ZnO and Zn2SiO4leachates were about two orders of magnitude higher than that of ZnAl2O4leachate at the end of the experiment, indicating that ZnAl2O4formation is the preferred stabilization mechanism for incorporating zinc in ceramic products. [ABSTRACT FROM PUBLISHER]

This paper describes the effect of Zn on the gas production of a fluidized-bed gasifier to determine the relationship between Zn and the gasification process. Different concentrations of Zn were used in the preparation of artificial waste to elucidate the effect on gas product composition, gas product heat value, gas production rate, and H2yield in the gasification process. Zn served to increase H2generation during the gasification process. The molar percentage of H2with more than 0.1 wt% additional Zn increased by 33.02% and the H2yield was increased by 11.34% compared to that without Zn. However, the gas heat value decreased, and no significant change in the gas production rate was noted. [ABSTRACT FROM PUBLISHER]

In this study, zinc recovery from lead–zinc–copper ore was performed by column flotation with and without ultrasonic pretreatment. First, optimization of operational parameters was carried out by only single-stage column flotation without ultrasonic pretreatment. A zinc concentrate containing 16.93% Zn was obtained from the feed containing 2.71% Zn with 29.41% recovery using single-stage column flotation. Second, a concentrate containing 24.51% Zn was obtained with a recovery of 39.97% when ultrasonic pretreatment was applied to zinc beneficiation by single-stage column flotation at these optimized conditions. Third, a zinc concentrate having 53.41% Zn was produced with a recovery of 71.48% by using three stages of cleaning and three stages of scavenging flotation by column. Finally, a zinc concentrate containing 73.32% Zn was received with a recovery of 76.44% when the ultrasonic pretreatment was used before column flotation by multiple stages. The results revealed that zinc grade and recovery were increased by ultrasonically assisted column flotation tests. It may be due to the increasing dispersion of ultrasound, increasing adsorption of collectors, and the hydrodynamic cavitation which produced small bubbles attaching to the hydrophobic particles, thereby increasing contact angle and attachment. [ABSTRACT FROM AUTHOR]

The aim of this paper is the characterization of spent NiCd batteries and the characterization of an industrial Black Mass obtained after crushing spent NiCd batteries and physical separation in a treatment plant. The characterization was first performed with five cylindrical NiCd batteries which were manually dismantled. Their characterization includes mass balance of the components, active powders elemental analysis and phase identification by X-ray powder diffraction. Chemical speciation of the two metals was also investigated. For cadmium, speciation was previously developed on solid synthetic samples. In a spent battery, the active powders correspond to about 43% of the battery weight. The other components are the separator and polymeric pieces (5%), the support plates (25%) and the carbon steel external case (27%). The sequential procedure shows that the nickel in the positive powders from the dismantled Ni–Cd batteries is distributed between Ni0(39.7%), Ni(OH)2(58.5%) and NiOOH (1.8%). Cadmium in the negative powder is about 99.9% as the Cd(OH)2form with 0.1% of metal cadmium. In the industrial Black Mass, the distribution of cadmium is the same, whereas the distribution of nickel is Ni0(46.9%), Ni(OH)2(43.2%) and NiOOH (9.9%). This material contains also 1.8% cobalt and approx. 1% iron. [ABSTRACT FROM PUBLISHER]

Group 12 metal complexes of bis-[2-{2,3-dioxane-2-yl}ethyl] telluride (L¹) and 2-{2-(4-fluoro phenyl telluro) ethyl}-1,3-dioxane (L²) having the formulae [ZnCl2-¹] (1), [ZnCl2.L²] (2), [CdCl2.L¹] (3), [Cdl2.L1] (4), [CdCl2.L²] (5), [HgCl2-L¹] (6), (HgBr2.L¹] (7), [HgI2-L¹] (8), and [HgCl2-L²] (9), [HgI2-L²] (10) were prepared and characterized on the basis of physico-chemical and spectral (FT-IR, ESI-MS, ¹H, 13C, 125Te NMR, and SEM) studies. The oxidation state ofTe changes to (+IV) in the formation of [bis-[2-{ 1,3-dioxane-2yl} ethyl] tellurium (IV) dibromide] 11, which crystallizes in the monoclinic system with space group c2/c. The geometry of 11 is distorted trigonal bipyramidal with two methylene groups and lone pair of electrons surrounding tellurium occupying the equatorial positions, while two bromine atoms are positioned axially. [ABSTRACT FROM AUTHOR]

A two-season pot experiment was conducted on Phaseolus vulgaris L. plants to evaluate their response to 1.0 mM salicylic acid (SA) in a growing medium contaminated with 0.25 or 0.50 mM Cd2+ ions. Plants were sampled for growth measurements and chemical analyses 45 d after sowing, and to measure the yield of beans at the end of each experiment. Exposing plants to either concentration of Cd2+ ions resulted in significant declines in growth, pigment concentrations, relative water content, and nutrient concentrations, and in chlorophyll fluorescence (FJFm) and the performance index (PI) of photosynthesis. However, 1.0 mM SA mitigated Cd2+ ion stress and significantly improved each of these parameters. Both Cd2+ ion treatments increased proline and Cd2+ ion concentrations, electrolyte leakage, and lipid peroxidation (measured as malondialdehyde concentration). However, 1.0 mM SA attenuated the adverse effects of Cd2+ ions on these characteristics. Cd2+-induced increases in the activities of several key anti-oxidant enzymes such as superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase were reduced following the exogenous application of 1.0 mM SA. These results confirm that the application of 1.0 mM SA could be used to reduce the adverse effects of Cd2+ ion toxicity in bean plants. [ABSTRACT FROM AUTHOR]

Phytoextraction using indica rice plants (Indian RiceOryza ssp.) is a promising technique for remediating cadmium (Cd)-polluted paddy fields. Because this technique has only been established for paddy fields, we decided to examine phytoextraction in upland fields that have been converted from paddy fields. Although “CHOKOUKOKU” shows a shattering habit and lodging, its Cd uptake was significantly higher than that of other indica rice varieties. On the other hand, “IR8”, which was able to accumulate only moderate levels of Cd in its shoots, has a lodging tolerance, making it an optimal variety for southwest Japan, which experiences several typhoons each year. Therefore, both “CHOKOUKOKU” and “IR8” were useful in estimating practical phytoextraction in upland fields. A practical phytoextraction examination showed that the total Cd uptake of “CHOKOUKOKU” and “IR8” was 822 and 545 g ha−1, respectively, after a 4-year period. After phytoextraction by planting high Cd-accumulating rice plants, the Cd concentration of the plot soil decreased by approximately 35%, compared to the initial Cd concentration. To evaluate phytoextraction efficiency in the upland field, wheat (Triticum aestivum) was subsequently grown in the remediation field. The Cd concentration in the grains of “SHIROGANEKOMUGI” grown in the phytoextraction plot was lower than that grown in a non-phytoextraction plot; regrettably, it exceeded the Codex Alimentarius Commission standard, whereas the grain Cd concentrations of “CHUGOKU165” planted in phytoextraction plots complied with the Codex standard for wheat grain. These results suggest that phytoextraction using high Cd-accumulating rice varieties is a practical remediation system for low Cd-polluted upland fields. Moreover, we determined the end point of the phytoextraction process, which occurs when the soil Cd concentration of the phytoextraction fields is less than 0.6 mg kg−1if “CHUGOKU165” is cultivated in this area. [ABSTRACT FROM PUBLISHER]

The article looks at the Hope Diamond, a type IIb diamond, which is housed by Smithsonian Institution’s Museum of Natural History, as of 2013. The author discusses the diamond's structure, origin and history. Special attention is paid to a gem called French Blue from which the Hope was later recut. Assumptions are made that the diamond's name originates from its former possessor Henry Philip Hope.

The article focuses on two South African diamonds which are part of the National Museum of Natural History's Gem Collection, owned by the Smithsonian Institution. The Portuguese Diamond is an emerald-cut gemstone and the Blue Heart is a type IIb diamond. The grading of the two diamonds by the Gemological Institute of America (GIA) is also provided.