• Journal of Life Science
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• v.24 no.3
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• pp.274-283
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• 2014

Oxidative stress causes tissue damage and facilitates the progression of metabolic diseases, including diabetes, cardiovascular heart diseases, and obesity. Lipid accumulation and obesity-related complications have been observed in the presence of extensive oxidative stress. As part of an ongoing study to develop therapeutic supplements, Sargassum sp. were tested for their ability to scavenge free radicals and intracellular reactive oxygen species (ROS), as well as to suppress lipid accumulation. Three species, S. hemiphyllum, S. thunbergii, and Sargassum horneri, were shown to scavenge free radicals in a di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium (DPPH) assay. In addition, Sargassum sp. was shown to scavenge intracellular ROS and to decrease nitric oxide (NO) production in $H_2O_2$ and lipopolysaccharide (LPS)-induced in RAW264.7 mouse macrophages, respectively. Taken together, the results suggest that Sargassum sp. possess huge potential to relieve oxidative stress and related complications, as well as lipid-induced oxidation. They indicate that S. hemiphyllum, S. thunbergii, and S. horneri are potent functional supplements that can produce beneficial health effects through antioxidant and antiobesity activities, with S. hemiphyllum being the most potent among the Sargassum sp. tested. A potential mechanism for the effect of Sargassum sp. on the suppression of lipid accumulation in differentiating 3T3-L1 mouse preadipocytes through deactivation of the peroxisome proliferator-activated receptor ${\gamma}$ (PPAR ${\gamma}$) is presented.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.1
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• pp.27-34
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• 2008

This study investigated the anti-hypertensive effect of Phyllostachys pubescens culm extract (PCE) by examining its effects on renal angiotensin-converting enzyme (ACE) inhibition and blood pressure using the spontaneously hypertensive rat (SHR) system. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured weekly for 8 weeks. Also, total antioxidant capacity and protein oxidation of tissues were examined by plasma Trolox Equivalent Antioxidant Capacity assay (TEAC) and hepatic protein carbonyl values, respectively. Twenty male SHR were randomly divided into four groups: PCE50, PCE100, and PCE500 (50, 100, and 500 mg of PCE per kilogram bodyweight daily, respectively), and control group. At week 2, the SBP in all PCE groups appeared to be significantly lower than the control (p<0.05), whereas the DBP were not different until week 4 (p<0.05). At week 8, SBP in the PCE500 was lower by 20% than the control. PCE groups considerably suppressed ACE dose-dependently compared with the control. Plasma TEAC and hepatic protein carbonyl values indicated increased antioxidative activity due to the PCE feed. No adverse effect was observed on the liver of SHR as there was no difference for the GOT and GPT values among the groups. Results of this study suggest that ACE inhibition may be one possible mechanism for the blood pressure lowering effect of PCE; thus, long term consumption of PCE may be beneficial in preventing high blood pressure along with the increased antioxidative status.

• Analytical Science and Technology
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• v.22 no.4
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• pp.285-292
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• 2009

It has been observed that, after long term storage, some ammunitions are misfired by tamping (combustionstopping) due to aging of the chemicals loaded in the ammunitions. Used in ammunitions are percussion powder which provides the initial energy, igniter which ignites the percussion powder, and a delay system that delays the combustion for a period of time. The percussion powder is loaded first, followed by the igniter and then the delay system, and the ammunitions explode by the energy being transferred in the same order. Tamping occurs by combustion-stopping of the igniter or insufficient energy transfer from the igniter to the delay system or the combustion-stopping of the delay system, which are suspected to be caused by low purity of the components, inappropriate mixing ratio, size distribution of particulate components, type of the binder, blending method, hydrolysis by the humidity penetrated during the long term storage, and chemical changes of the components by high temperature. Goal of this study is to find the causes of the combustion-stopping of the igniter and the delay system of the ammunitions after long term storage. In this study, a method was developed for testing of the combustion-stopping, and the size distributions of the particulate components were analyzed with field-flow fractionation (FFF), and then the mechanism of chemical change during long term storage was investigated by thermal analysis (differential scanning calorimetry), XRD (X-ray diffractometry), and XPS (X-ray photoelectron spectroscopy). For the ignition system, M (metal)-O (oxygen) and M-OH peaks were observed at the oxygen's 1s position in the XPS spectrum. It was also found by XRD that $Fe_3O_4$ was produced. Thus it can be concluded that the combustion-stopping is caused by reduction in energy due to oxidation of the igniter.

• Economic and Environmental Geology
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• v.35 no.5
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• pp.379-393
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• 2002

Within the Boseong-Jangheung area of Korea, five hydrothermal gold (-silver) quartz vein deposits occur. They have the characteristic features as follows: the relatively gold-rich nature of e1ectrurns; the absence of Ag-Sb( -As) sulfosalt mineral; the massive and simple mineralogy of veins. They suggest that gold mineralization in this area is correlated with late Jurassic to Early Cretaceous, mesothermal-type gold deposits in Korea. Fluid inclusion data show that fluid inclusions in stage I quartz of the mine area homogenize over a wide temperature range of 200$^{\circ}$ to 460$^{\circ}$C with salinities of 0.0 to 13.8 equiv. wt. % NaCI. The homogenization temperature of fluid inclusions in stage II calcite of the mine area ranges from 150$^{\circ}$ to 254$^{\circ}$C with salinities of 1.2 to 7.9 equiv. wt. % NaCI. This indicates a cooling of the hydrothermal fluid with time towards the waning of hydrothermal activity. Evidence of fluid boiling including CO2 effervescence indicates that pressures during entrapment of auriferous fluids in this area range up to 770 bars. Calculated sulfur isotope composition of auriferous fluids in this mine area (${\delta}^34S$_{{\Sigma}S}$$\textperthousand$) indicates an igneous source of sulfur in auriferous hydrothermal fluids. Within the Sobaegsan Massif, two representative mesothermal-type gold mine areas (Youngdong and Boseong-Jangheung areas) occur. The ${\delta}^34S values of sulfide minerals from Youngdong area range from -6.6 to 2.3$\textperthousand$ (average=-1.4$\textperthousand$, N=66), and those from BoseongJangheung area range from -0.7 to 3.6$\textperthousand$ (average=1.6$\textperthousand$, N=39). These i)34S values of both areas are comparatively lower than those of most Korean metallic ore deposits (3 to 7TEX>$\textperthousand$). And, within the Sobaegsan Massif, the ${\delta}^34S values of Youngdong area are lower than those of Boseong-Jangheung area. It is inferred that the difference of ${\delta}^34S values within the Sobaegsan Massif can be caused by either of the following mechanisms: (1) the presence of at least two distinct reservoirs (both igneous, with ${\delta}^34S values of < -6 $\textperthousand$ and 2$\pm$2 %0) for Jurassic mesothermal-type gold deposits in both areas; (2) different degrees of the mixing (assimilation) of 32S-enriched sulfur (possibly sulfur in Precambrian pelitic basement rocks) during the generation and/or subsequent ascent of magma; and/or (3) different degrees of the oxidation of an H2S-rich, magmatically derived sulfur source ${\delta}^34S = 2$\pm$2$\textperthousand$) during the ascent to mineralization sites. According to the observed differences in ore mineralogy (especially, iron-bearing ore minerals) and fluid inclusions of quartz from the mesothermal-type deposits in both areas, we conclude that pyrrhotite-rich, mesothermal-type deposits in the Youngdong area formed from higher temperatures and more reducing fluids than did pyrite(-arsenopyrite)-rich mesothermal-type deposits in the Boseong-Jangheung area. Therefore, we prefer the third mechanism than others because the ${\delta}^34S values of the Precambrian gneisses and Paleozoic sedimentary rocks occurring in both areas were not known to the present. In future, in order to elucidate the provenance of ore sulfur more systematically, we need to determine ${\delta}^34S values of the Precambrian metamorphic rocks and Paleozoic sedimentary rocks consisting the basement of the Korean Peninsula including the Sobaegsan Massif.