Crystalline Nickel Sulfide Research Articles

Crystalline/amorphous nickel sulfide interface for high current density in alkaline HER: surface and volume confinement matters!

In this work, we demonstrate an interface on porous nickel foam (NN) between crystalline nickel sulfide and amorphous nickel sulfide (NNS/NNSx) adapting simple hydrothermal and facile electrodeposition processes, respectively. The developed electrocatalyst required a low overpotential of 15 mV to deliver a current density of 10 mA cm-2 and the interface intrinsically activates the electrocatalyst with an onset overpotential comparable to that of Pt in an alkaline hydrogen evolution reaction.

Crystalline nickel sulfide integrated with amorphous cobalt sulfide as an efficient bifunctional electrocatalyst for water splitting

The development of highly efficient and low-cost electrocatalysts is critical to the mass production of hydrogen from water splitting. Herein, a facile yet effective method was developed to synthesize bimetallic sulfides Ni3S2/CoSx, which were aimed for use as the electrocatalysts in both HER and OER. Encouragingly, the Ni3S2/CoSx demonstrated a low overpotential of 110 mV for HER at a current density of 10 mA·cm−2. It was discovered that the surface of Ni3S2/CoSx during OER process would undergo an in-situ oxidation to form MOOH (M = Co, Ni), that is, MOOH/Ni3S2/CoSx were the real functioning species in catalysis, which had an excellent OER activity and a low overpotential of 226 mV. Additionally, the assembled electrolyzer required only a low cell voltage of 1.53 V to achieve a current density of 10 mA·cm−2 in a 1 M KOH solution, and its performance was stable. Overall, this work provided a promising strategy for the facile fabrication of low-cost amorphous electrocatalysts, which is expected to promote the progress of overall water splitting.

Self-Supported Amorphous-Edge Nickel Sulfide Nanobrush for Excellent Energy Storage

Transition metal sulfides, which attract great attention as pseudocapacitance electrodes with high specific capacitance exceeding those of traditional metal oxides, but still suffer from relatively low activity and inferior cycling life. Herein, freestanding and hierarchical nickel sulfide (NiS) electrodes with amorphous-edge and nanobrush structures (AENSNB) are successfully prepared based on the self-sacrificial nickel foam as Ni resource and a facile sulfurization process. Benefiting from the merits of amorphous-edge, hierarchical and self-growth architectures, the AENSNB electrode shows greatly improved electrochemical performance with high capacitance (5.59Fcm−2 at 10mAcm−2). More importantly, it also exhibits a long cycling stability possessing 94.9% capacitance retention after 10000 cycles. The hybrid architecture design for crystalline NiS covered by amorphous edges can be deemed as an effective method to gain pseudocapacitive material for supercapacitors with good conductivity, long cycle life and excellent electrochemical activity.

Surfactant-assisted synthesis of nanoporous nickel sulfide flakes and their hybridization with reduced graphene oxides for supercapacitor applications

We report a simple soft-templating strategy for the synthesis of nanoporous crystalline nickel sulfide with two-dimensional (2-D) morphology.

Preparation by a facile method and characterization of amorphous and crystalline nickel sulfide nanophases

Abstract A simple solvothermal route using a domestic microwave oven has been developed to prepare the prominent nickel sulfide nanophases (amorphous NiS, and crystalline NiS 1.03 , β-NiS and α-NiS). The prepared nanophases have been characterized chemically, structurally, optically, electrically, and magnetically by the available methods like thermogravimetric and differential thermal analyses, X-ray powder diffraction analysis, scanning electron microscopic, and transmission electron microscopic analyses, energy dispersive X-ray spectroscopic, Fourier transform-infrared spectral, UV–Vis spectral and photoluminescence spectral analyses, AC and DC electrical measurements at various temperatures in the range 40–150 °C, and vibrating sample magnetometric measurements. The average particle sizes obtained through transmission electron microscopic analysis are 15, 17, 18, 20 nm respectively for the amorphous NiS, NiS 1.03 , β-NiS and α-NiS nanophases. Results obtained in the present study indicates that the method adopted is found to be an effective and economical one for preparing these nanophases with high purity, reduced size, homogeneity, and useful optical, electrical and magnetic properties.

Epigenetic alterations in immortal human bronchial epithelial cells transformed by crystalline nickel sulfide

Epigenetic alterations in immortal human bronchial epithelial cells transformed by crystalline nickel sulfide

Identification of protein peroxiredoxin 2 related to crystalline NiS-induced neoplastic transformation

To provide evidence for illustrating the molecular mechanism of nickel carcinogenesis, and to identify the differential expression of protein in crystalline NiS-induced neoplastic transformation of human bronchial epithelial cell by proteomics technology. Two dimensional electrophoresis (2-DE) and the ImageMaster 3.10 software were used to analyze the differential expression of protein, matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS) combined with database search was applied to identify protein peroxiredoxin 2 (PDX2) related to malignant transformation. The good 2-DE pattern including resolution and reproducibility was obtained. Nearly 700 expressed proteins per 2-D gel were isolated with molecular weights (MW) ranging from 14,400 to 94,000 KD and pI 3 - 10. A protein PDX2 with MW 21,890 KD, pI 5.66, which was highly expressed in malignantly transformed cell, was identified using MALDI-TOF-MS. PDX2 was involved in malignant transformation of human bronchial epithelial cell induced by crystalline nickel sulfide.

Crystalline nickel sulfide-induced genomic instability in transformed human broncho-epithelial cells

To detect the genomic instability in the 16 human broncho-epithelial (16HBE) cells induced by crystalline nickel sulfide so as to provide the scientific basis for further study of nickel-induced cancer molecular mechanism. To analyse the genomic instability in transformed 16HBE cells induced by crystalline nickel sulfide by random amplified polymorphic DNA (RAPD). All the 7 random primers selected could amplify 1 - 6 clear PCR bands. There were no significant differences between transformed 16HBE cells and negative control cells in the 4th, 5th, and 7th primers, but in the rest 4 primers there were significant differences, with special PCR bands for the same primer, indicating that genomic instability in transformed 16 HBE cells was induced by crystalline nickel sulfide. Crystalline nickel sulfide could induce genomic instability in 16HBE cells.

Nickel enhances telomeric silencing in Saccharomyces cerevisiae

Certain nickel compounds including crystalline nickel sulfide (NiS) and subsulfide (Ni 3S 2) are potent human and animal carcinogens. In Chinese hamster embryo cells, an X-linked senescence gene was inactivated following nickel-induced DNA methylation. Nickel also induced the inactivation of the gpt reporter gene by chromatin condensation and a DNA methylation process in a transgenic gpt+ Chinese hamster cell line (G12), which is located near a heterochromatic region. To determine if nickel can cause gene silencing independently of DNA methylation, based only on the induction of changes in chromatin structure, we measured its effect on gene silencing in Saccharomyces cerevisiae. Growth of yeast in the presence of nickel chloride repressed a telomeric marker gene (URA3) and resulted in a stable epigenetic switch. This phenomenon was dependent on the number of cell doubling prior to selection and also on the distance of the marker gene from the end of the chromosome. The level of TPE (telomeric position effect) increased linearly with elevations of nickel concentration. Addition of magnesium inhibited this effect, but magnesium did not silence the reporter gene by itself. The level of silencing was also assessed following treatment with other transition metals: cobalt, copper and cadmium. In the sublethal range, cobalt induced similar effects as nickel, while copper and cadmium did not change the basal level of gene expression. Silencing by copper and cadmium were evident only at concentrations of those metals where the viability was very low.

Preparation and properties of uniform amorphous and crystalline colloidal nickel sulfide

Amorphous spherical particles of nickel sulfide of 10 nm in diameter were synthesized by the controlled double-jet precipitation (CDJP) technique using nickel sulfate and sodium sulfide. Cubic crystalline particles of 200 nm were obtained by aging dispersions of amorphous particles at 80 °C for more than a week, as long as the pH was kept between 3 and 3.5. Electrokinetic mobilities of these particles are reported, as well as color properties of their dispersions in liquids and in poly(vinyl alcohol) films are described.

Effect of Nickel Sulfide on Induction of Interleukin-1 and Phagocytic Activity

Rat peritoneal macrophages were treated with crystalline nickel sulfide (NiS), washed, and then tested for interleukin-1 (IL-1) production and phagocytosis of IgG-opsonized sheep red blood cells (SRBC). Pretreatment of peritoneal macrophages with crystalline NiS did not affect their ability to produce IL-1. In contrast, pretreatment of peritoneal macrophages with crystalline NiS inhibited the phagocytic activity of the peritoneal macrophage. This inhibitory activity was due to an effect on the internalization step of the phagocytic process. The binding step of this process was not affected by exposure to crystalline NiS. The overall number of Ig-SRBC that interacted with each macrophage was not different in treated or untreated cultures. This interaction is mediated through Fc receptors on the macrophage membrane. This result suggests that crystalline NiS does not modulate the expression of Fc receptors by peritoneal macrophages. The results described in this study suggest that crystalline NiS has a potent immunomodulatory effect on macrophage phagocytic activity.

Mutagenicity of soluble and insoluble nickel compounds at the gpt locus in G12 chinese hamster cells

Nickel is an established human and animal carcinogen, but efforts to demonstrate its mutagenicity in a number of cell types have not been successful. In this report we describe the mutational response to nickel compounds in the G12 cell line, an hprt deficient V79 cell line containing a single copy of the E. coli gpt gene. This cell line has a low spontaneous background, making it suitable for assessment of mutagenic responses to environmental contaminants. When G12 cells were treated with insoluble particles of crystalline nickel sulfide < 5 microns in diameter, a strong, dose-dependent mutagenic response was observed up to 80 times the spontaneous background. Of 48 mutant gpt(-) clones isolated that were induced by insoluble nickel, all were capable of DNA amplification of the gpt sequences by polymerase chain reaction (PCR). The ability to produce full-length PCR products is an indication that large deletions of gene sequences have not occurred. When G12 cells were treated with soluble nickel sulfate, the mutational response was not significantly increased over the spontaneous background. This difference in mutagenic response reflects a large difference in the mutagenic potential of soluble and insoluble nickel compounds, which reflects the carcinogenic potential of these forms of nickel.

Characteristics of the inhibition of interferon-α/β production after crystalline nickel sulfide exposure

Murine L-929 cells were treated with crystalline nickel sulfide (NiS), washed, and then exposed to polyriboinosinic-polyribocytidylic acid (Poly I:C) to induce interferon-alpha/beta (IFN-alpha/beta). Addition of crystalline NiS at different time points, from 24 hr prior to IFN induction (pretreatment) up to 12 hr after IFN induction, resulted in significant inhibition of IFN-alpha/beta production. In addition, 24-hr pretreatment of L-929 cells with crystalline NiS resulted in significantly decreased production of IFN-alpha/beta even 120 hr after addition of IFN inducer. IFN-alpha/beta at a known concentration was titered by means of a viral plaque reduction assay in crystalline NiS-treated L-929 cell cultures. Crystalline NiS did not show a significant inhibitory effect on the antiviral activity of IFN on L-929 cells as compared to controls. The results described here suggest that NiS has a rapid and a long-lasting inhibitory activity on the production of IFN-alpha/beta.

Potentiation of lymphocyte proliferative responses by nickel sulfide.

Crystalline nickel sulfide (NiS) induced a spleen cell proliferation that resembles a mixed lymphocyte reaction (MLR). It depended on cell-cell interaction, induced high levels of interleukin-1 (IL-1) and interleukin-2 (IL-2) and the responding cell subpopulation was composed of CD4+ T lymphocytes. Furthermore, the proliferation was inhibited in a dose-dependent manner by magnesium. Crystalline NiS also increased significantly the spleen cell proliferative response to concanavalin A (Con A) and lipopolysaccharide (LPS) with magnesium potentiating the combined effects of crystalline NiS and mitogens. Interestingly, crystalline NiS did not show any effect on the induction of IL-2 by Con A. The results described herein suggest that crystalline NiS can potentiate both antigenic (MLR) and mitogenic (Con A and LPS) proliferative responses in vitro. Crystalline NiS appears to potentiate these responses by acting in the form of ionic nickel on several intracellular targets for which magnesium ions have different noncompetitive interactions. The effects of magnesium on the potentiating action of crystalline NiS are different depending upon the type of primary stimulatory signal for proliferation (mitogenic or antigenic).

Effects of amorphous and crystalline nickel sulfide on induction of interferons-α/β and -γ and interleukin-2

Pretreatment of rat spleen cells with crystalline or amorphous nickel sulfide (NiS) did not inhibit induction of interferon-gamma or interleukin-2 by concanavalin A. In contrast, pretreatment of murine L-929 cells with crystalline NiS inhibited severely IFN-alpha/beta induction by polyriboinosinic-polyribocytidylic acid, while amorphous NiS did not show any effect. This difference in the effects of both forms of NiS on the spleen and L-929 cells correlated with the cellular internalization of the compound; L-929 cells actively phagocytosed crystalline NiS while the uptake of amorphous NiS by the same type of cells was minimal. The uptake of both crystalline and amorphous NiS by spleen cells was very low.

Chromosomal changes in cell lines from mouse tumors induced by nickel sulfide and methylcholanthrene.

Rhabdomyosarcomas were induced in mice by intramuscular injections of crystalline nickel sulfide and 3-methylcholanthrene. At early passage, karyotypes were performed by G-banding for four nickel sulfide cell lines and for three 3-methylcholanthrene cell lines. Six cell lines were near-diploid and one nickel sulfide line was near-tetraploid. Three of the nickel sulfide cell lines were characterized by a rearranged marker chromosome which was present in a majority of the cells of each line. The rearrangements leading to the formation of marker chromosomes were different in each nickel sulfide cell line but involved chromosome 4 in two of the nickel sulfide cell lines. Extra copies of chromosome 15 were present in two nickel sulfide cell lines. Possible rearrangement and/or gene activation was examined for the c-mos oncogene on chromosome 4 and the c-myc oncogene on chromosome 15, but no alteration or activation was observed. None of the 3-methylcholanthrene cell lines contained rearranged marker chromosomes; however, one MCA cell line did contain large numbers of double minutes. In all cell lines, minichromosomes (small atypical acrocentric chromosomes) were observed that contained distinct centromeric regions but no other G-positive bands.

Chromosomal alterations in cell lines derived from mouse rhabdomyosarcomas induced by crystalline nickel sulfide.

Prior studies have shown a preferential decondensation (or fragmentation) of the heterochromatic long arm of the X chromosome of Chinese hamster ovary cells when treated with carcinogenic crystalline NiS particles (crNiS). In this report, we show that the heterochromatic regions of mouse chromosomes are also more frequently involved in aberrations than euchromatic regions, although the heterochromatin in mouse cells is restricted to centromeric regions. We also present the karyotypic analyses of four cell lines derived from tumors induced by leg muscle injections of crystalline nickel sulfide which have been analyzed to determine whether heterochromatic chromosomal regions are preferentially altered in the transformed genotypes. Common to all cell lines was the presence of minichromosomes, which are acrocentric chromosomes smaller than chromosome 19, normally the smallest chromosome of the mouse karyotype. The minichromosomes were present in a majority of cells of each line although the morphology of this extra chromosome varied significantly among the cell lines. C-banding revealed the presence of centromeric DNA and thus these minichromosomes may be the result of chromosome breaks at or near the centromere. In three of the four lines a marker chromosome could be identified as a rearrangement between two chromosomes. In the fourth cell line a rearranged chromosome was present in only 15% of the cells and was not studied in detail. One of the three major marker chromosomes resulted from a centromeric fusion of chromosome 4 while another appeared to be an interchange involving the centromere of chromosome 2 and possibly the telomeric region of chromosome 17.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential effects of amorphous and crystalline nickel sulfide on murine [formula omitted] interferon production

Mouse embryo fibroblast cultures were exposed to various concentrations of amorphous or crystalline NiS (nickel sulfide). After removal of the NiS from the cultures, polyriboinosinic-polyribocytidylic acid was added to induce α β interferon. Pretreatment of the cultures with crystalline NiS significantly inhibited the production of α β interferon at relatively noncytotoxic concentrations (i.e., 1 μg/ml) while amorphous NiS had no significant effect on α β interferon production at 10 μg/ml. Treatment of cells with reduced glutathione did not block the inhibitory effects of crystalline NiS on α β interferon production, suggesting that these effects are not mediated by a free-radical mechanism.

Extracellular requirements for the endocytosis of carcinogenic crystalline nickel sulfide particles by facultative phagocytes

Various culture medium components were examined for their effect upon the phagocytosis of carcinogenic crystalline and non-carcinogenic amorphous NiS by cultured fibroblastic cells using both a visual and radioactive assay for phagocytosis. Crystalline NiS was phagocytosed by cells in a simple salts/glucose maintenance medium to an extent similar to that observed in complex culture medium fortified with 10% fetal bovine serum (FBS), suggesting that serum proteins and other components in complex culture medium exert little influence upon the uptake of these heavy metal particles. Phagocytosis of crystalline NiS was shown to be highly dependent upon Ca 2+since omission of Ca 2+ from the salts/glucose medium substantially reduced phagocytosis, while readdition of Ca 2+ stimulated uptake in a concentration-dependent manner. The uptake of the NiS particles was inhibited by trifluoperazine, a calmodulin antagonist, implicating intracellular Ca 2+ in this phagocytosis process. Since the opposite surface charge of crystalline and amorphous NiS has been related to their different phagocytic uptake by cells whose primary function is not phagocytosis (facultative phagocytes), these results show that the culture medium components do not modify the surface charge of these particles in a way that significantly influences their uptake.

Cytoplasmic dissolution of phagocytized crystalline nickel sulfide particles: a prerequisite for nuclear uptake of nickel.

The intracellular fate of particulate crystalline alpha NiS, an inducer of neoplastic transformation which is readily phagocytized by cultured cells, was compared with that of particulate amorphous NiS, which does not have these properties. Amorphous and crystalline NiS both dissolve slowly in complete medium; phagocytized alpha NiS particles remain in the cytoplasm, where they dissolve more rapidly than extracellular particles. Thus the selective phagocytosis of alpha NiS accounts for both high intracellular particle accumulation and high levels of soluble Ni relative to the surrounding medium. Since phagocytized alpha NiS particles do not enter the nucleus, dissolution in the cytoplasm may represent an activation step in carcinogenesis, forming soluble Ni which diffuses into the nucleus. Dissolution products from phagocytized alpha NiS were detected in subcellular fractions isolated from treated cells; the highest levels were found in the nuclei, mitochondria, and lysosomes. That the Ni in the subcellular fractions was dissolved is suggested by the fact that dissolution products from phagocytized alpha NiS were detected in nuclei after centrifugation on sucrose pads, which substantially reduced contamination from cytoplasmic alpha NiS particles. Cytoplasmic dissolution of alpha NiS was enhanced by prior exposure of cells to the same compound. Loss of visible particles from cells was compared with loss of total Ni by use of alpha 63 NiS particles; the particles disappeared from almost half the cells during the first 2 d of treatment, while the total radioactivity associated with the cells and the total number of cells in the monolayer remained the same. The accelerated dissolution of alpha NiS after exposure to the same particles may be due to enhancement of lysosomal enzyme activity by particle phagocytosis. A 20-30% increase in intracellular acid phosphatase activity was observed after treatment with crystalline, but not amorphous, NiS, suggesting enhanced lysosomal activity.