• Journal of Magnetics
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• v.10 no.3
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• pp.118-121
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• 2005

We have investigated the magnetic properties of electroplated thin Cu/Co multilayers by using electrolytes made of copper sulphate and cobalt sulphate and by applying alternating plating voltage. While the multilayers plated with pure electrolyte showed superparamagnetism, those plated with organic additives showed ferromagnetic behavior. These changes are attributed to the so-called 'self-annealing' effect and reduction of grain size caused by the organic additives.

• Journal of Veterinary Clinics
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• v.7 no.2
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• pp.451-469
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• 1990

The present study was carried out to investigate whether the aloe had a radioprotective effect in mice exposed to cobalt-60 gamma radiation or not. The survival ratio of mice for 30 days, hematopoiesis of blood-forming stem cells by spleen colony assay, chromosomal aberration frequency of bone marrow cells and histopathological findings of bone marrow were investigated. The survival ratios of aloe administered groups with concentration of 250, 500, 1,000 and 1,500mg for 3 days before irradiation and control group in cobalt-60 gamma irradiated mice(700rads whole body irradiation, dose rate of 50rads/min.) were 77.4, 79.3, 80.6, 90.0 and 53.1％, respectively. The survival ratios of pre-irradiation aloe administered groups were superior to those of post-irradiation aloe groups and control group. In spleen colony assay, Aloe vera administration before irradiation enhanced the recoveries of numbers of blood-forming stem cells of bone marrow of irradiated mice. There were decreased chromosomal aberrations of bone marrow cells at the first day after irradiation in aloe administered groups compared to that of control group. Histopathological findings in the bone marrow of irradiated mice were hypocellularity due to the depletion of myelocytes, abundant of fat vacuoles and these changes were weakened in aloe administered groups compared to that of control group.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.6 no.1
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• pp.33-38
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• 1976

The author observed the effects of the cobalt-60 irradiation on the amelogenesis and dentinogenesis of the albino rat fetuses by means of histological and histochemical methods. Females in oestrus were mated overnight and examined the next morning for evidence of copulation. The lower left abdomen of mothers were exposed to cobalt-60 irradiation on the 10th day of gestation, l00R 200R and 300R respectively. The fetuses were removed from the mothers on the 18th day of gestation. The employed histochemical methods were PAS reaction, colloidal iron reaction, aldehyde fuchsin stain, α-amino acid reaction, -SH radical reaction and methyl- green pyronin stain. The results were as follows; 1. The group irradiated by l00R made no histological differences in comparison with the control group. 2. Increasing the irradiation to 200R, abnormal dentin formation occured, and resulted in enamel hypoplasia and in atrophy and necrosis of odontoblasts. In dentinal papilla, the dilation and the degeneration of the blood vessels, excessive reticular atrophy and osteodentin were revealed. 3. With the more irradiation (200R-300R), the positive material of PAS, α-amino acid and aldehyde fuchsin tended to decrease in the ameloblast and the odontoblast. No significant changes appeared in DNA, the stainability of methylgreen pyronin.

• Korean Journal of Materials Research
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• v.32 no.10
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• pp.408-413
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• 2022

The oxygen evolution reaction (OER) is very sluggish compared to the hydrogen evolution reaction (HER). Considering this difference is essential when designing and developing a cost-effective and facile synthesis method for a catalyst that can effectively perform OER activity. The material should possess a high surface area and more active sites. Considering these points, in this work we successfully synthesized sheets of cobalt phosphate hydrate (CP) and sulphurated cobalt phosphate hydrate (CPS) material, using simple successive ionic layered adsorption and reaction (SILAR) methods followed by sulfurization. The CP and CPS electrodes exhibited overpotentials of 279 mV with a Tafel slope of 212 mV dec^-1 and 381 mV with a Tafel slope of 212 mV dec^-1, respectively. The superior performance after sulfurization is attributed to the intrinsic activity of the deposited well-aligned nanosheet structures, which provided a substantial number of electrochemically active surface sites, speeded electron transfer, and at the same time improved the diffusion of the electrolyte.

• Journal of Powder Materials
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• v.11 no.1
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• pp.16-21
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• 2004

The nano-sized Co particles were successfully synthesized by chemical vapor condensation (CVC) process using the precursor of cobalt carbonyl ($Co_2(CO)_8$). The influence of carrier gases on the microstructure and magnetic properties of nanoparticles was investigated by means of XRD, TEM, XPS and VSM. The Co nano-particles with different phases and shapes were synthesized with a change of carrier gas : long string morphologies with coexistence of fcc and hcp structure in Ar carrier gas condition; finer Co core in a mass of cobalt oxide with only fcc structure in He; rod type cobalt oxide phase in Ar＋6vol％$O_2$. The saturation magnetization and coercivity was lower in Co nanoparticles synthesized in He carrier gas, due to their finer size.

• Microbiology and Biotechnology Letters
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• v.14 no.5
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• pp.355-358
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• 1986

The effects of cobalt chloride, methionine, and various carbon sources on the sisomicin production by M. inyoensis NRRL 3292 were investigated. It was found that both cobalt chloride and methionine exerted a greater stimulatory effect on sisomicin formation. Kinetic studies with various carbon sources revealed thai polysaccharide such as starch or dextrin was found io be better than glucose for sisomicin production Moreover, the relatively low concentration of dissolved carbon dioxide was one of the most important factors In accelerating sisomicin production during idiophase.

• Transactions of the Korean hydrogen and new energy society
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• v.15 no.2
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• pp.144-151
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• 2004

The effect of the cobalt content on the thermodynamic and, heat and mass transfer properties of the $MmNi_{5-y}B_{y-z}C_z(y=0.5{\sim}1.5,\;z=0.5)$hydrogen storage alloys has been studied systematically. The P-C isotherms curves show that with increasing cobalt content in the alloys, the plateau pressure of the hydrogen absorption and desorption and enthalpy(${\Delta}H$) increases steeply and the plateau region becomes flat, while entropy(${\Delta}S$) decreases. Also at the constant cobalt content the hydrogen transfer rate decreases with the reaction temperature, while the initial reaction kinetics increases. But the initial reaction with hydrogen completes within 1min, although the reaction proceeds about 30minutes thereafter.

• Molecules and Cells
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• v.27 no.5
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• pp.533-538
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• 2009

Heat shock protein 27 (Hsp27) is a molecular chaperone protein which regulates cell apoptosis by interacting directly with the caspase activation components in the apoptotic pathways. With the assistance of the Tat protein transduction domain we directly delivered the Hsp27 into the myocardial cell line, H9c2 and demonstrate that this protein can reverse hypoxia-induced apoptosis of cells. In order to characterize the contribution of Hsp27 in blocking the two major apoptotic pathways operational within cells, we exposed H9c2 cells to staurosporine and cobalt chloride, agents that induce mitochondria-dependent (intrinsic) and -independent (extrinsic) pathways of apoptosis in cells respectively. The Tat-Hsp27 fusion protein showed a greater propensity to inhibit the effect induced by the cobalt chloride treatment. These data suggest that the Hsp27 predominantly exerts its protective effect by interfering with the components of the extrinsic pathway of apoptosis.

• Journal of the Korean Chemical Society
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• v.23 no.1
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• pp.52-58
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• 1979

Metallic dialkyldithiophosphates are widely used in lubricating oils as antioxidant and antiwear agents. Zinc DDTP are used most frequently in lubricating oil. Zinc, lead, tin and cobalt DDTP were prepared with primary and secondary alkyl groups. The effects of oxidation, thermal stability, metal corrosion and antiwear of each metallic DDTP prepared were studied. Based on the results, cobalt DDTP has a significant effect of antiwear on chrome alloy steel comparing with the other metallic DDTP. Also cobalt DDTP has a characteristic property of thermal sensitivity in its color, which was shown by the color change from brown to blue over a certain temperature. Another phenomenon obtained was that all metallic DDTP initiates the effect of antioxidation at the time of reaching to a certain effective acid concentration in lubricating oil.

• Proceedings of the Materials Research Society of Korea Conference
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• 1997.05a
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• pp.95-95
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• 1997