Concentrations Of Cobalt Chloride Research Articles

MITF regulates the subcellular location of HIF1α through SUMOylation to promote the invasion and metastasis of daughter cells derived from polyploid giant cancer cells.

High concentrations of cobalt chloride (CoCl2) can induce the formation of polyploid giant cancer cells (PGCCs) in various tumors, which can produce daughter cells with strong proliferative, migratory and invasive abilities via asymmetric division. To study the role of hypoxia‑inducible factor (HIF) 1α in the formation of PGCCs, colon cancer cell lines Hct116 and LoVo were used as experimental subjects. Western blotting, nuclear and cytoplasmic protein extraction and immunocytochemical experiments were used to compare the changes in the expression and subcellular localization of HIF1α, microphthalmia‑associated transcription factor (MITF), protein inhibitor of activated STAT protein4 (PIAS4) and von Hippel‑Lindau disease tumor suppressor (VHL) after treatment with CoCl2. The SUMOylation of HIFα was verified by co‑immunoprecipitation assay. After inhibiting HIF1α SUMOylation, the changes in proliferation, migration and invasion abilities of Hct116 and LoVo were compared by plate colony formation, wound healing and Transwell migration and invasion. In addition, lysine sites that led to SUMOylation of HIF1α were identified through site mutation experiments. The results showed that CoCl2 can induce the formation of PGCCs with the expression level of HIF1α higher in treated cells than in control cells. HIF1α was primarily located in the cytoplasm of control cell. Following CoCl2 treatment, the subcellular localization of HIF1α was primarily in the nuclei of PGCCs with daughter cells (PDCs). After treatment with SUMOylation inhibitors, the nuclear HIF1α expression in PDCs decreased. Furthermore, their proliferation, migration and invasion abilities also decreased. After inhibiting the expression of MITF, the expression of HIF1α decreased. MITF can regulate HIF1α SUMOylation. Expression and subcellular localization of VHL and HIF1α did not change following PIAS4 knockdown. SUMOylation of HIF1α occurs at the amino acid sites K391 and K477 in PDCs. After mutation of the two sites, nuclear expression of HIF1α in PDCs was reduced, along with a significant reduction in the proliferation, migration and invasion abilities. In conclusion, the post‑translation modification regulated the subcellular location of HIF1α and the nuclear expression of HIF1α promoted the proliferation, migration and invasion abilities of PDCs. MITF could regulate the transcription and protein levels of HIF1α and participate in the regulation of HIF1α SUMOylation.

Equilibrium of the solubility isotherm in systems Cobalt(II) chloride-glutamic acid-water

The study is focused on the interaction between glutamic acid and hexavodic cobalt chloride. The solubility curve, influenced by the high solubility of the initial components, extends horizontally along a catheter corresponding to the cobalt chloride content. The secretion of glutamic acid exhibits a gradual increase over a relatively extended period. As the cobalt chloride concentration in the solution reaches 25.04%, a new phase emerges, resulting from the molecular interaction of the reactants, forming a double dihydrous compound comprising one molecule of glutamic acid and cobalt chloride: C5H9NO4∙CoCl2.

Study of the doping effect of CoCl2 on the structural, optical and electrical properties of polyvinyl alcohol (PVA)

Cobalt chloride (CoCl2) doped with polyvinyl alcohol (CH2CHOH) n films, were synthesized by solution casting method. The pure PVA and doped [PVA: CoCl2] films were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, dc electrical conductivity and UV–VIS spectroscopy. The SEM analysis confirmed the presence of uniformly distributed Co2+ ions in the polymer matrix. FT-IR spectra provide information on the structure of the doped PVA and signify the intermolecular hydrogen bonding between Co2+ ions with the OH group of PVA. From the optical studies, it is found that the optical band gap (Eg) decreases with an increase in the dopant concentration. The dc electrical studies revealed that the conductivity of the doped PVA is significantly higher than that of pristine PVA and conductivity is found to increase with the temperature. The activation energy decreases at the lower concentrations of cobalt chloride, whereas it becomes constant at higher concentrations

Development of cobalt-incorporated chitosan scaffold for regenerative potential in human dental pulp stem cells: An in vitro study

The aim of the study was to comparatively evaluate chitosan and Cobalt incorporated chitosan (CoCH) scaffold at varying concentrations in terms of their material characteristics, cytotoxicity and cell adhesion potential. In the present study, cobalt incorporated chitosan scaffolds at varying concentrations were prepared and dried. The synthesised scaffolds were characterised using XRD, FTIR, SEM-EDX and BET which revealed amorphous, porous surface of CoCH scaffolds and FTIR analysis showed the complexation confirming the chelation of cobalt with chitosan. The experimental scaffolds proved to be non-cytotoxic when compared to chitosan scaffolds on XTT analysis. Cell-seeding assay revealed enhanced adherence of hDPSCs to CoCH scaffold at 1:1 ratio in the concentration of 100 mL of 100 μmol/L cobalt chloride solution in 100mL of 2% chitosan solution, when compared to other groups. The results highlighted that 100 μmol/L concentration of cobalt chloride when incorporated in 1:1 ratio into 2 % CH solution yields a promising porous, biocompatible scaffold with enhanced cellular adhesion for dentin-pulp regeneration.

Bioadsorption – To Clean Match Industry Effluent Toxicity

This study investigates the possibility of applying an adsorption process using seaweed dry powder natural seaweeds the adsorbents were used to treat real match industry effluent. Bioadsorption is an effective low-cost tool for cleaning polluted environment. In the present study the seedlings of Vigna mungo (L) Hepper were treated with various concentrations of match industry effluent and their impact on the growth, biochemical and enzyme characters were studied. After fourteen days treatment with different concentration of match industry effluent (20%, 40%, 60%, 80% and 100%) the growth parameter such as,shoot and root lengths, leaf area, fresh weight and dry weight were decreased than the control. Biochemical parameters such as chlorophyll, carotenoids, soluble sugar, protein content and nitrate reductase activity also decreased with the increase in the concentration of cobalt chloride. But the content of free amino acid, proline, phenol and leaf nitrate content were increased with the increase in the concentration of cobalt chloride. The activities of enzyme such as catalase, peroxidase and polyphenol oxidase were found to be increased with the increase in the concentration of match industry effluent. Application of seaweed (Sargassum wightii) in different concentrations (2gm/L, 4gm/L and 6gm/L) on 60% efluent treated plants has shown the stress relieving effect caused by the toxins of match industry effluent. It is good low cost bioadsorbant for match industry effluent pollution.

Cobalt Chloride Promotes Osteogenesis of Rat Bone Marrow Mesenchymal Stem Cells In Vitro and In Vivo

This work aimed to investigate the effect of low-concentration cobalt chloride on the in vitro and in vivo proliferation of rat bone mesenchymal stem cells, the expression of hypoxia-inducing fraction-1 alpha and the related osteogenic genes. The bone mesenchymal stem cells were isolated from bone marrow of rats, and the surface biomarkers were identified by immunofluorescence staining and flow cytometry. The differentiation of bone mesenchymal stem cells was measured by alizarin red and alkaline phosphatase staining. The bone mesenchymal stem cells were treated with cobalt chloride at different concentrations and cell viability was assessed by cell counting kit 8. Cell migration was detected by Transwell and wound healing assay. The expression of collagen type 1, bone morphogenetic protein-2, runt-related transcription factor 2, alkaline phosphatase and hypoxia-inducing fraction-1 alpha were measured by quantitative real time polymerase chain reaction assay. The large segmental defect model was made to mimic the in vivo bone defect. The bone mesenchymal stem cells-collagen sponge scaffold was adopted for in vivo treatment and histological analysis of femur structure was performed to assess the effects of cobalt chloride-treated bone mesenchymal stem cells in promoting bone formation. X-ray and micro computed tomography were performed to observe bone structure. The cluster of differentiation 90 and cluster of differentiation 44 were highly expressed and cluster of differentiation 45 expression was relatively low in isolated bone mesenchymal stem cells. The cobalt chloride at 300 and 400 μmol/l could effectively suppress cell proliferation, compared with the control group. The low dose of cobalt chloride (50 μmol/l and 100 μmol/l) could promote cell proliferation. The cobalt chloride at 100 μmol/l could increase the positive staining of alkaline phosphatase and alizarin red. The expression of collagen type 1, bone morphogenetic protein-2, runt-related transcription factor 2, alkaline phosphatase and hypoxiainducing fraction-1 alpha were statistically up-regulated by cobalt chloride treatment. The cobalt chloridebone mesenchymal stem cells-collagen scaffold effectively accelerated the bone regeneration, increased new bone deposition and bone morphogenetic protein-2 expression in femur tissues. Appropriate concentration of cobalt chloride can promote the proliferation of bone mesenchymal stem cells and up-regulate the expression of hypoxia-inducing fraction-1 alpha and osteogenic genes in vitro, simultaneously promoted bone regeneration in vivo.

Optimal conditions for vitamin B12 production from

This research was conducted to study the effect of some nutrients on the growth and production of vitamin B12 by Lactobacillus genus L.rhamnosus, when their ability to produce vitamin B12 was tested under different conditions. The results indicate that a pH of 7 is optimal for vitamin B12 production by the bacteria L.rhamnosus and it was found that the optimum incubation temperature for the production of vitamin B12 ranged between 30 - 35 °C, with regard to the effect of the incubation period on the biological activity and productivity of vitamin B12. The results showed that 3 days was the best in the production of vitamin B12. The results also showed that adding the lowest concentration of cobalt chloride gave a high productivity of the vitamin compared to the highest added concentrations and that the best carbon source was sucrose among the three carbon sources that included glucose, fructose, and sucrose, and the results of the study showed that the best nitrogen source It is was peptone compared to yeast extract, which gave the highest production of the vitamin B12.

Instantaneous synthesis and full characterization of organic–inorganic laccase-cobalt phosphate hybrid nanoflowers

A novel approach termed the "concentrated method" was developed for the instant fabrication of laccase@Co3(PO4)2•hybrid nanoflowers (HNFs). The constructed HNFs were obtained by optimizing the concentration of cobalt chloride and phosphate buffer to reach the highest activity recovery. The incorporation of 30 mM CoCl2 and 160 mM phosphate buffer (pH 7.4) resulted in a fast anisotropic growth of the nanomaterials. The purposed method did not involve harsh conditions and prolonged incubation of precursors, as the most reported approaches for the synthesis of HNFs. The catalytic efficiency of the immobilized and free laccase was 460 and 400 M−1S−1, respectively. Also, the enzymatic activity of the prepared biocatalyst was 113% of the free enzyme (0.5 U mL−1). The stability of the synthesized HNFs was enhanced by 400% at pH 6.5–9.5 and the elevated temperatures. The activity of laccase@Co3(PO4)2•HNFs declined to 50% of the initial value after 10 reusability cycles, indicating successful immobilization of the enzyme. Structural studies revealed a 32% increase in the α-helix content after hybridization with cobalt phosphate, which improved the activity and stability of the immobilized laccase. Furthermore, the fabricated HNFs exhibited a considerable ability to remove moxifloxacin as an emerging pollutant. The antibiotic (10 mg L−1) was removed by 24% and 75% after 24 h through adsorption and biodegradation, respectively. This study introduces a new method for synthesizing HNFs, which could be used for the fabrication of efficient biocatalysts, biosensors, and adsorbents for industrial, biomedical, and environmental applications.

Effects of Exogenous Ethylene and Cobalt Chloride on Root Growth of Chinese Fir Seedlings under Phosphorus-Deficient Conditions

Studying the effects of different concentrations of ethephon on morphological and physiological changes in the roots of Chinese fir (Cunninghamia lanceolata Lamb. Hook.) seedlings under P deficiency can reveal the internal adaptive mechanisms of these plants under nutrient stress. Herein, we investigated the effects of different ethephon and cobalt chloride concentrations under normal P supply and P deficiency. A significant effect (p < 0.05) of exogenous additive application was observed on the development of Chinese fir root length, surface area, and volume. These root development indices showed maximum values when the ethephon concentration was 0.01 g kg−1 under normal P supply and P deficiency, and they were significantly different from those under 0.04 g kg−1 ethephon treatment. Similarly, the indices showed maximum values when CoCl2 concentration was 0.01 g kg−1 under P deficiency and was significantly different (p < 0.01) from those under 0.2 g kg−1 CoCl2 treatment. Under normal P supply, an increase in ethephon concentration caused superoxide dismutase (SOD; E.C. 1.15.1.1) activity to decrease and peroxidase (POD; E.C. 1.11.1.X) activity to increase gradually. Conversely, CoCl2 addition (0.01 g kg−1) promoted SOD and POD activities under P deficiency. There were no significant differences (p > 0.05) in malondialdehyde content of seedlings among ethephon or CoCl2 treatments. In conclusion, ethylene plays a significant role in adaptative mechanisms underlying stress resistance in plants, prompting them to respond to P starvation and improving seedlings’ tolerance to P-deficient conditions.

Effect of Probenecid on Endothelial Cell Growth Rate and Retinal Angiogenesis in an Oxygen-Induced Retinopathy Model.

Objectives: Probenecid is an anion transport inhibitor, which, according to the connectivity map (CMap; a biological application database), interferes with hypoxia-induced gene expression changes in retinal vascular endothelial cells (ECs). Here, we investigated the influence of probenecid on retinal EC cytotoxicity and retinal neovascularization in a murine oxygen-induced retinopathy (OIR) model. Methods: The retinal EC growth rate in the presence of hypoxia-mimicking concentrations of cobalt chloride (CoCl2) was determined using the thiazolyl blue tetrazolium bromide (MTT) assay and proliferating cell nuclear antigen (PCNA) expression. In OIR rats, probenecid was administered by intraperitoneal injection (i.p.) from postnatal day (P) 1 to P7. The concentrations of vitreous humor vascular endothelial growth factor (VEGF), hypoxia-inducible factor (HIF)-1α, and placental growth factor (PlGF) were determined by using the ELISA kit at P21. The amount of newly formed vascular lumen was evaluated by histopathological examination. Retinopathy and neovascularization were assessed by scoring isolectin B4 fluorescein–stained retinal flat mounts. Western blots for liver tissue HIF-1α and hepcidin (HAMP) were performed. Results: In vitro, probenecid led to the recession of the hypoxia-induced EC growth rate. In vivo, compared to the OIR retina, the upregulation of VEGF, HIF-1α, and PlGF in phase II retinopathy of prematurity (ROP) was inhibited by probenecid administration. Moreover, probenecid ameliorated neovascularization and resulted in significantly reduced relative leakage fluorescence signal intensity in fluorescein-stained retinal flat mounts (p < 0.05). Probenecid alleviated the liver overactivation of HAMP and downregulation of HIF-1α in OIR rats. Conclusions: This is the first demonstration that implies that probenecid might be a protective compound against retinal angiogenesis in OIR. These changes are accompanied with decreased hyperoxia-mediated hepcidin overproduction. Although the relevance of the results to ROP needs further research, these findings may help establish potential pharmacological targets based on the CMap database.

Dose- and time-dependent changes in viability and IL-6, CXCL8 and CCL2 production by HaCaT-cells exposed to cobalt. Effects of high and low calcium growth conditions.

Sensitization requires exposure to an allergen with subsequent production of a "danger "signal. In the skin, keratinocytes are the main producers of these signals. To compare dose- and time-effects of cobalt on the viability of and cytokine release from HaCaT cells cultured at low or high calcium. To model two separate states of differentiation of keratinocytes, HaCaT cells were cultured under low or high calcium conditions. HaCaT were exposed to different concentrations of cobalt chloride (10 μm to 5 mM) over time (30 minutes- 48 hours). Cell viability was measured with the Cell-Titer Blue Viability assay. Cytokine production was measured using a bead-based immunoassay and flow cytometry. Gene expression was quantified using qPCR. Data was analyzed by ANOVA and linear mixed model. Viability of the cells was dose- and time-dependent. A linear mixed statistical model showed that cobalt exposure induces increase in IL-6, CXCL8 and CCL2 production over time and whereas increase of IL-6 and a decrease of CCL2 was associated with increasing cobalt chloride concentrations. When comparing the cells incubated under high and low calcium conditions, the more differentiated cells in the high concentration were found to exert a stronger response in terms of IL-6 release. Our data suggest that cobalt chloride triggered an alarm system in HaCaT cells, and proinflammatory cytokines/chemokines were secreted in a dose- and time-dependent manner. When high and low calcium incubations were compared, the difference was seen only for IL-6. These findings indicate that the effect of cobalt chloride on cell toxicity occurs throughout the living epidermis.

Investigation of the thermal, mechanical and biological properties of PVC/ABS blends loaded with cobalt chloride for biomedical and electronics applications

New PVC/ABS and CoCl2 composites with various concentrations of cobalt chloride (?10 wt. %) were synthesized by solution casting techniques and investigated by spectro-chemical, morphological and thermal mode of characterization. The FT-IR, XRD and SEM analyses proved the smooth distribution and uniformity of the constituents of the composite materials. Thermal behavior showed that the addition of CoCl2 to the PVC/ABS blends enhanced the thermal stability and improved mechanical properties of composites due to crosslinking between PVC/ABS blend and CoCl2. Thus based on their remarkable morphology, thermomechanical stability and promising bioactivities, the synthesized composites could be applied for high performance polymeric materials in the field of biomedics and electronics.

Serum Creatinine Electrochemical Biosensor on Printed Electrodes Using Monoenzymatic Pathway to 1-Methylhydantoin Detection.

The rising prevalence of Chronic Kidney Disease (CKD) has necessitated efforts towards the development of cost-effective and accurate biosensors for serum creatinine, which is a potent biomarker reflecting kidney function. This work presents a novel and cost-effective technique to estimate serum creatinine without any sample preprocessing. The technique involves the conversion of creatinine by a monoenzymatic pathway to 1-methylhydantoin. The concentration of 1-methylhydantoin is then quantified by utilizing its innate ability to form a complex with transition metals such as cobalt. The complex formation has been validated using optical spectroscopy and the transmittance at 290 nm wavelength is used to identify the optimum concentration of cobalt chloride in sensing chemistry. This chemical assay is shown to be robust against interference from serum albumin, the abundant plasma protein that can potentially influence the sensor response. The electrochemical biosensor developed using screen-printed electrodes thus provides highly selective creatinine estimation over the range of 0.2–4 mg/dL in a sample volume of 300 μL with no preprocessing and hence can be easily translated into a viable point-of-care (POC) device.

Effect of Cobalt Chloride Concentration on Structural, Optical and Electrical Properties of Co3O4 Thin Films Deposited by Pneumatic Spray

Effect of Cobalt Chloride Concentration on Structural, Optical and Electrical Properties of Co3O4 Thin Films Deposited by Pneumatic Spray

Tanshinone IIA Inhibits VEGF Secretion and HIF-1α Expression in Cultured Human Retinal Pigment Epithelial Cells under Hypoxia

ABSTRACTPurpose: The current work intends to study the activity of tanshinone IIA on secretion of vascular endothelial growth factor (VEGF) and expression of hypoxia inducible factor 1α (HIF-1α) in human retinal pigment epithelial cells (ARPE-19 cells) under hypoxic condition.Methods: The cytotoxicity of tanshinone IIA was tested in ARPE-19 cells by MTT assay. ARPE-19 cells were incubated with different concentrations of cobalt chloride (100, 150, and 200 µM) for 12 h, and levels of expressed HIF-1α and secreted VEGF were quantified through Western blot and ELISA, respectively. Further, ARPE-19 cells were pretreated for 1 h with different concentrations of tanshinone IIA (5, 10, 15, and 18 µM). After 1 h, the cells were subjected to hypoxic condition using 150 µM cobalt chloride for 12 h in the presence and absence of tanshinone IIA. The cells were then harvested, and the secreted VEGF and expressed HIF-1α was studied.Results: Tanshinone IIA at concentrations of 5, 10, 15, and 18 μM did not show cytotoxicity in ARPE-19 cells. Chemical hypoxia induced by cobalt chloride caused a significant increase in VEGF level in a dose-dependent manner, and HIF-1α expression peaked at 150 µM. Based on the data, cobalt chloride concentration was maintained at 150 μM for further studies. Tanshinone IIA decreased the level of HIF-1α and VEGF secretion in a dose-dependent manner under hypoxic condition.Conclusion: Tanshinone IIA could be explored as a new potential candidate for treating wet AMD.

Assessment of the impact of ethylene and ethylene modulators in Citrus limon organogenesis

The aim of this study was to evaluate the influence of ethylene-releasing (ACC, Ethephon, Methionine) and -inhibiting (cobalt chloride, silver thiosulfate) compounds on ethylene production and shoot organogenesis of nodal segments, where buds were completely removed, from mature tissues of Citrus limon, Fino 49 and Verna 51 cultivars. The addition of ACC to the culture medium produced a very significant decrease of the regeneration. These results were directly related to the ethylene levels measured in the atmosphere inside the tube. Similar results were observed with ethephon and methionine; the gradual increase in ethylene levels in the tubes, with increasing ethylene-releasing compounds in the culture medium, agrees with the decrease in the regeneration rate observed, but the effect was lower than with ACC. When cobalt chloride (CoCl2) was added to the culture medium, contrary to what was expected, the regeneration decreased in both cultivars and this decreasing was not related with the increase in ethylene production. These observations matched the occurrence of yellowish necrotic explants increasing the concentration of cobalt chloride, probably because of a toxic effect on lemon explants. The increase of silver thiosulfate (STS) in the culture medium enhanced the regeneration percentage in both Verna 51 and Fino 49 cultivars. Nevertheless, ethylene levels increased proportionally with the STS concentration and the regeneration rate. These results may be explained since the effects produced by the high ethylene levels measured in STS experiments were blocked by Ag+ ions, thereby increasing the regeneration percentage. Media to which STS was added produced the highest regeneration percentages. The results obtained in this study showed that ethylene plays an important role in the organogenesis of mature explants of C. limon.

Role of ethylene in germination and seedling growth of littleseed canarygrass (Phalaris minor Retz.)

Littleseed canarygrass is a major weed of wheat in rice–wheat cropping system of North-West India. The present study was conducted to study the role of ethylene in germination ecology and seedling growth of littleseed canarygrass and wheat using cobalt chloride (inhibitor of ethylene synthesis) and ethephon (ethylene source). Cobalt chloride at concentrations ≥0.1 mM caused significant reduction in germination (%), germination index and increased the mean germination time of littleseed canarygrass, whereas wheat seeds exhibited significant decrease in germination (%) at cobalt chloride concentrations ≥0.5 mM. Cobalt chloride at higher concentrations significantly reduced the seedling growth of littleseed canarygrass and wheat with more pronounced effect on root length as compared to shoot length. It also significantly increased the membrane leakage and soluble sugar content of seedlings of both species with concomitant decrease in chlorophyll and protein content. Ethephon at 0.1 and 1 mM concentrations significantly increased the germination (%), speed of germination with concomitant decrease in mean germination time as compared to control. Ethephon concentrations 0.1 and 1 mM had no effect on membrane leakage, total soluble sugars and protein content but increased the chlorophyll content in seedlings of both species. Seed dormancy of littleseed canarygrass induced by higher concentrations of cobalt chloride, i.e., 2.5 and 5 mM could also be overcome by treatment with 1 mM ethephon, confirming the role of ethylene in germination of this weed.

Structural, Optical and Thermal Study on PEO‐Based Solid Polymer Electrolyte for Optical Device Applications

SummaryThe polymer electrolytes based polyethylene oxide‐cobalt chloride (PEO‐CoCl2) films were prepared by solution casting technique and its structural property was examined by XRD study. The XRD data revealed that the amorphous nature of polymer matrix increased with increase of dopant concentration. The absorption spectra was measured in the wave range from 200–800 nm. The direct optical band gap (Eg) found decreased with increasing the concentration of cobalt chloride. The optical activation energy was evaluated using Urbach‐edges method. The thermal properties of these films were investigated with thermogravimetric analysis (TGA). The variation in film morphology is examined by scanning electron microscopy examination (SEM). Studies on the structural and optical properties of polymer electrolyte have attracted much attention in view of their application in optical devices like electro‐chromic display devices, fuel cells, gas sensors and solid state batteries.

The studies of cobalt nanoparticles on the toxicity and biological activity of osteoclast

Objective To explore the toxicity and biological activity of cobalt nanoparticles (CoNPs) on osteoclasts, and to analyze the relationship between cobalt nanoparticles and osteolysis. Methods From November 2014 to July 2015, RAW264.7 cell was induced to osteoclastlike cell by LPS. Different concentrations of cobalt nanoparticles and cobalt chloride were added, and the cell morphology was observed under a microscope. 24 h after induction on RAW264.7, cells were grouped in- to cobalt nanoparticles group (10, 20, 50, 100 μmol/L), cobalt chloride group (10, 20, 50, 100 mol/L) and control group. MTT assessment and Q-PCR were performed at 2 h, 4 h, 8 h, 24 h, 48 h post-treatment. Results With the increase of concentration (10, 20, 50, 100 μmol/L) and the action time (2 h, 4 h, 8 h, 24 h, 48 h), the inhibition rate of cobalt nanoparticles and cobalt chloride on osteoclast like cells was significantly increased, and the inhibition rate of cobalt nanoparticles was higher. With different concentrations (10, 20, 50, 100 μmol/L) of CoNPs and cobalt chloride, the relative expression of CAII, Cat K gene mRNA expression decreased compared with the control group, when the concentration of CoNPs was in the range of 10-50 μmol/L, the relative expression of CAII and Cat K was increased, which was reduced in cobalt chloride group. Conclusion Different concentrations of cobalt nanoparticles and cobalt chloride can inhibit the proliferation and differentiation of osteoclasts, and cobalt nanoparticles is more pronounced, when the concentration of cobalt nanoparticles was 10-50 μmol/L, the relative expression of osteoclasts CAII, Cat K increaseed, which was suppressed at the same concentration of cobalt chloride. Key words: Osteoclasts; Cobalt; Toxic actions

Patterns due to an interplay between viscous and precipitation-driven fingering

Dynamics related to the interplay of viscous fingering with precipitation-driven patterns are studied experimentally in a horizontal Hele-Shaw cell with radial injection. The precipitation reaction, known to produce chemical gardens, involves a cobalt chloride metallic salt solution and a more viscous sodium silicate one. The properties of the fingering precipitation patterns are studied as a function of the flow rate of injection, of the viscosity ratio between the two solutions and of the concentration of the reactants. We show that, for the viscous silicate solution used here, viscous fingering shapes flower-like patterns at low metallic salt concentrations but is not the driving mechanism in the development of spirals and filaments at larger cobalt chloride concentrations. In some cases, enhanced convective motions induced by viscous fingering also increase the amount of precipitate by increasing the mixing between the two reactants.