• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.2
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• pp.87-94
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• 2012

To compare monthly variations of phytoplankton biomass and community composition between in seawater and sediment of the Gomso Bay (tidal flat: approximately 75%), the photosynthetic pigments were analyzed by HPLC every month in 1999 and every two months in 2000. Ambient physical and chemical parameters (temperature, salinity, nutrients, dissolved oxygen, and chemical oxygen demand) were also examined to find the environmental factors controlling structure of phytoplankton community. The temporal and spatial variations of chlorophyll a concentration in seawater were correlated well with the magnitude of freshwater discharge from land. The biomass of microphytobenthos at the surface sediments was lower than that in other regions of the world and 2-3 times lower than phytoplankton biomass integrated in the seawater column. Based on the results of HPLC pigment analysis, fucoxanthin, a marker pigment of diatoms, was the most prominent pigment and highly correlated with chlorophyll a in seawater and sediment of the Gomso Bay. These results suggest that diatoms are the predominant phytoplankton in seawater and sediment of the Gomso Bay. However, the monthly variation of chlorophyll a concentration in seawater at the subtidal zone was not a good correlation with that in sediment of the Gomso Bay. Although pelagic plankton was identified in seawater by microscopic examination, benthic algal species were not found in the seawater. These results suggest that contribution from the suspended microphytobenthos in the tidal flat to the subtidal zone of the Gomso Bay may be low as a food source to the primary consumer in the upper water column of the subtidal zone. Further study needs to elucidate the vertical and horizontal transport magnitude of the suspended microphytobenthos in the tidal flat to the subtidal zone.

• Journal of the Mineralogical Society of Korea
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• v.25 no.4
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• pp.271-282
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• 2012

We explore the effect of removal of organic ligand on the atomic configurations around oxygen in hydroxyl groups in amorphous silica gel (synthesized through hydrolysis of $SiCl_4$ in diethyl-ether) using high resolution $^{17}O$ solid state NMR spectroscopy. $^1H$ and $^{29}Si$ MAS NMR spectra for amorphous silica gel showed diverse hydrogen environments including water, hydroxyl groups (e.g., hydrogen bonded silanol, isolated silanol), and organic ligands (e.g., alkyl chain) that may interact with surface hydroxyls in the amorphous silica gel, for instance, forming silica-organic ligand complex (e.g., Si-$O{\cdots}R$). These physically and chemically adsorbed organic ligands were partly removed by ultrasonic cleaning under ethanol and distilled water for 1 hour. Whereas $^{17}O$ MAS NMR spectra with short pulse length ($0.175{\mu}s$) at 9.4 T and 14.1 T for as-synthesized amorphous silica gel showed the unresolved peak for Si-O-Si and Si-OH structures, the $^{17}O$ MAS NMR spectra with long pulse length ($2{\mu}s$) showed the additional peak at ~0 ppm. The peak at ~0 ppm may be due to Si-OH structure with very fast relaxation rate as coupled to liquid water molecules or organic ligands on the surface of amorphous silica gel. The observation of the peak at ~0 ppm in $^{17}O$ MAS NMR spectra for amorphous silica gel became more significant as the organic ligands were removed. These results indicate that the organic ligands on the surface of amorphous silica gel interact with oxygen atoms in Si-OH and provide the information about atomic structure of silanol and siloxane in amorphous silica gel. The current results could enhance the understanding of dehydration mechanism of diverse silicates, which is known as atomic scale origins of intermediate depth (approximately, 70~300 km) earthquakes in subduction zone.

• Tuberculosis and Respiratory Diseases
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• v.43 no.4
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• pp.600-612
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• 1996

Background : Recent studies deported that untreated patients with obstructive sleep apnea syndrome had high long-term mortality rates, and cardiovascular complications of these patients clad a major effect on mortality. Several data indicates that obstructive sheep apnea syndrome contributes to the development of diurnal systemic hypertension. But the pathophysiological mechanism of the development of systemic hypertension in these patients is still uncertain. This study was performed to evaluate the possible role of sympathetic nervous system activity for the development of systemic hypertension in patients with obstructive sleep apnea syndrome. Method : 35 patients with obstructive sleep apnea syndrome(OSAS) and 13 Control subjects(control) were included in this study. 21 patients of OSAS were normotensives(OSAS-NBP), and 14 patients of OSAS were hypertensives(OSAS-HBP). Full night polysomnography was undertaken to all subjects. We measured plasma norepinephrine(NE) and epinephrine(EP) concentrations during waking and sleep, using high performance liquid chromatography, in all patients and control subjects. Results : In OSAS, OSAS-NBP and control, plasma NE and EP concentrations during sleep were lowed than during waking(p<0.01). But, in OSAS-HBP, these was no difference between during waking and sleep. Plasma NE concentrations during sleep of OSAS, OSAS-NBP and OSAS-HBP were higher than Control(p<0.05). In OSAS-HBP, daytime systolic blood pressure correlated with plasma NE concentration during sleep(r=0.7415, p<0.01), arid correlated inversely with mean arterial oxygen saturation(r=-0.6465, p<0.05) or arterial oxygen saturation nadir(r=-0.6) 14, p<0.05) during sleep. Conclusion : The sympathetic activity during sleep of obstructive sleep apnea syndrome patients was higher than control subjects. In obstructive sleep apnea syndrome patients with systemic hypertension, there was no diurnal variation of sympathetic activity, and there was correlation between daytime systolic blood pressure and sympathetic activity during sleep. These data suggests that chronic hyperactivity of sympathetic nervous system may contribute to the development of diurnal systemic hypertension in patients with obstructive sleep apnea syndrome.

• Resources Recycling
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• v.28 no.6
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• pp.79-86
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• 2019

Recently, the use of lithium ion battery(LIB) has increased. As a result, the price of lithium and the amount spent lithium on ion battery has increased. For this reason, research on recycling lithium in waste LIBs has been conducted1). In this study, the effect of roasting for the selective lithium leaching from the spent LIBs is studied. Chemical transformation is required for selective lithium leaching in NCM LiNi_xCo_yMn_zO₂) of the spent LIBs. The carbon in the waste EV cell powder reacts with the oxygen of the oxide at high temperature. After roasting at 550 ~ 850 ℃ in the Air/N₂ atmosphere, the chemical transformation is analysed by XRD. The heat treated powders are leached at a ratio of 1:10 in D.I water for ICP analysis. As a result of XRD analysis, Li₂CO₃ peak is observed at 700 ℃. After the heat treatment at 850 ℃, a peak of Li₂O was confirmed because Li₂CO₃ is decomposed into Li₂O and CO₂ over 723 ℃. The produced Li₂O reacted with Al at high temperature to form LiAlO₂, which does not leach in D.I water, leading to a decrease in lithium leaching ratio. As a result of lithium leaching in water after heat treatment, lithium leaching ratio was the highest after heat treatment at 700 ℃. After the solid-liquid separation, over 45 % of lithium leaching was confirmed by ICP analysis. After evaporation of the leached solution, peak of Li₂CO₃ was detected by XRD.

• Journal of Food Hygiene and Safety
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• v.31 no.5
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• pp.386-392
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• 2016

This study investigated the isoflavone content, total phenol content, antioxidant activities (DPPH radical scavenging and oxygen radical absorbance capacity) and ${\beta}$-glucan content of defatted soybean extracts by bioconversion. Soybean was fermented with Lentinula edodes using submerged liquid fermentation system. Defatted soybean powder prepared by hexane (HDS; hexane defatted soybean) and ethanol (EDS; ethanol defatted soybean). The major components of non-fermented HDS (NFHDS) and EDS (NFEDS) were glucoside, such as daidzin, glycitin and genistin. During the bioconversion processing, isoflavone glucoside converted into aglycone such as daidzein, glycitein and genistein. The highest total isoflavone contents of fermented HDS (FHDS) were $2577.96{\mu}g/mL$, and the lowest total isoflavone contents of NFEDS were $428.27{\mu}g/mL$. The highest total phenol contents of fermented EDS (FEDS) was 42.34 mg GAE/g. DPPH radical scavenging and ORAC value were 31.30 to 59.92% and 247.48 to $786.36{\mu}M\;TE/g$ in non-fermented defatted soybean and fermented soybean, respectively. ${\beta}$-Glucan contents were 0.09 to 0.11% in non-fermented defatted soybean and fermented soybean, respectively. These results indicate that fermented soybean could be used as natural antioxidants for the development of functional foods.

• Journal of Preventive Medicine and Public Health
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• v.28 no.2 s.50
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• pp.511-525
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• 1995

To elucidate some DNA adducts as a biological marker for workers of chromate pigment, the effects of chromium exposure on the formation of 8-hydroxydeoxyguanosine(8-OH-dG) and sister chromatid exchanges(SCEs) frequency in 38 workers of a pigment plant in Bucheon which utilized lead chromates, were examined. The chromium contents of venous blood and urine were measured as working environmental exposure level. The concentrations of 8-OH-dG in DNA isolated from lymphocytes were determined with high performance liquid chromatography and electrochemical detector and denoted as a molar ratio of 8-OH-dG to deoxyguanosine(dG). The SCEs frequency were analyzed in DNA isolated from lymphocytes. A significant correlation was found between creatinine adjusted urine chromium concentration and the molar ratio of 8-OH-dG to dG(r=0.47, p<0.01). After adjusting the current smoking habit, the correlation coefficient was increased(r=0.62, p<0.05). However, there was no significant correlation between the SCE frequency and chromium exposure. This significant results between molar ratio of 8-OH-dG to dG and chromium exposure are in good agreement with in vitro studies that support the importance of DNA adduct formation for the carcinogenic effect of chromium.

• Economic and Environmental Geology
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• v.36 no.2
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• pp.75-87
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• 2003

The Haman-Gunbuk mineralized area is located within the Cretaceous Gyeongsang Basin along the southeastern part of the Korean peninsula. Major ore minerals, magnetite, scheelite, molybdenite and chalcopyrite, together with base-metal sulfides and minor sulfosalts, occur in fissure-filling tourmaline, quartz and carbonates veins contained within Cretaceous sedimentary and volcanic rocks anu/or granodiorite (118{\pm}$3.0 Ma). The ore and gangue mineral paragenesis can be divided into three distinct stages: Stage 1, tourmaline+quartz+Fe-Cu ore mineralization; Stage II, quartz+sulfides+sulfosalts+carbonates; Stage 111, barren calcite. Earliest fluids are recorded in stage I and early por-tions of stage II veins as hypersaline (35~70 equiv. wt.% NaCl+KCl) and vapor-rich inclusions which homogenize from ~30$0^{\circ}C$ to $\geq$50$0^{\circ}C$. The high-salinity fluids are complex chloride brines with significant concentrations of sodium, potassium, iron, copper, and sulfur, though sulfide minerals are not associated with the early mineral assemblage produced by this fluid. Later solutions circulated through newly formed fractures and reopened veins, and are recorded as lower-salinity(less than ~20 equiv. wt.% NaCl) fluid inclusions which homogenize primarily from ~200 to 40$0^{\circ}C$. The oxygen and hydrogen isotopic compositions of fluid in the Haman-Gunbuk hydrothermal system represents a progressive shift from magmatic-hydrothermal dominance during early mineralization stage toward meteoric-hydrothermal dominance during late mineralization stage. The earliest hydrothermal fiuids to circu-late within the granodiorite stock localiring the ore body at Haman-Gunbuk could have exsolved from the crystal-lizing magma and unmixed into hypersaline liquid and $H_2O$-NaCl vapor. As these magmatic fluids moved throughfractures, tourmaline and early Fe, W, Mo, Cu ore mineralization occurred without concomitant deposition of othersulfides and sulfosalts. Later solutions of dominantly meteoric origin progressively formed hypogene copper and base-metal sulfides, and sulfosalt mineralization.

• Korean Journal of Food Science and Technology
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• v.50 no.5
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• pp.517-527
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• 2018

The current study investigated in vitro anti-diabetic and neuroprotective effects of the ethyl acetate fraction in Actinidia arguta sprouts (EFAS), on $H_2O_2$ and high glucose-induced cytotoxicity in human neuroblastoma MC-IXC cells. EFAS had high total phenolic and total flavonoid contents. An assessment of 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity of EFAS, as well as its potential for inhibiting malondialdehyde production, indicated that EFAS may possess significant antioxidant properties. EFAS exerted inhibitory effects on ${\alpha}-glucosidase$ via glycemic regulation which forms advanced glycation end products. In addition, EFAS exhibited significant acetylcholinesterase inhibitory effects. Moreover, EFAS displayed protective effects against $H_2O_2$ and high glucose-induced cell death, and inhibited the generation of reactive oxygen species in MC-IXC cells. Finally, the main physiological compound of EFAS was identified via high performance liquid chromatography as a rutin.

• Journal of Life Science
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• v.21 no.8
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• pp.1163-1167
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• 2011

Excessive alcohol consumption causes various degenerative brain diseases including Alzheimer's disease and Parkinson's disease. Absorbed ethanol is metabolized to acetaldehyde and acetic acid by alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). Acetaldehyde is well known as a toxicant through generation of reactive oxygen species (ROS). Therefore, ALDH2 activity may play important roles in the pathogenesis of alcohol-induced brain diseases. In this study, we demonstrated the effects of ALDH2 enzyme activity on lipid peroxidation in brain tissues and urine of mice exposed to ethanol for 8 weeks. Five male, 8-week old Aldh2 (+/+) and Aldh2 (-/-) mice (C57BL/6J strain) in each group were exposed to ethanol for 8 weeks (2 g/kg wt./day) using gavage, and those in the control group received 0.9% saline alone. Thiobarbituric acid reactive substances (TBARS) level, a marker for lipid peroxidation, was measured in whole brain tissue and urine by high performance liquid chromatography. As a result, chronic ethanol treatment did not show any statistical change on the TBARS level of brain tissue in both Aldh2 (+/+) mice and in Aldh2 (-/-) mice. However, following ethanol exposure for 8 weeks in Aldh2 (-/-) mice, the urinary TBARS levels were significantly increased to more than double compared to the pretreatment group. This result was not observed in Aldh2 (+/+) mice. These results suggest that although ALDH2 enzyme activity plays a role in the generation of ROS in the whole body, it does not seem to be important in the pathogenesis of alcohol induced degenerative brain diseases.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.9
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• pp.1249-1256
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• 2016

Black ginseng (BG) obtained by a 9-fold steaming process of Panax ginseng has been reported to have anti-oxidative, anti-obesity, and anti-diabetes effects. The current study evaluated the protective effect of BG by steaming time in an HCl/ethanol-induced acute gastritis model. BG was divided into four samples according to steaming-drying processing (Gin1, Gin3, Gin6, and BG). High performance liquid chromatography analysis, free radical scavenging activity, and total phenol and flavonoid contents were examined in ginseng and four BG samples. Compared with ginseng, BG showed a stronger radical scavenging effect and higher contents of total phenol and flavonoids. To evaluate the anti-gastritic effect of BG, mice were distributed into five groups: normal mice (N), acute gastritic mice with distilled water (CON), acute gastritic mice with 100 mg/kg of ginseng (Gin0), acute gastritic mice with 100 mg/kg of BG (BG), and acute gastritic mice with 10 mg/kg of sucralfate (SC). After 1 hour of pre-treatment with water, extracts (Gin0 and BG), or drug (SC), experimental groups except for N were orally administered 0.5 mL of 150 mM HCl/60% ethanol (v/v) mixture. Blood was collected 1 hour later from the heart, and gastric tissue was harvested. Reactive oxygen species (ROS) levels were measured in serum, and related protein expression was examined by Western blot assay. In HCl/ethanol-induced acute gastritic mice, treatment with ginseng or BG improved mucosal damage in the histological evaluation. The serum ROS level significantly decreased in the BG-treated group compared with the CON group. Furthermore, expression of inflammatory cytokines significantly decreased in the BG-treated group compared with the CON group. Based on these results, antioxidant and anti-gastritic activities of ginseng were enhanced by streaming-drying processing, in part due to an increase in biological active compounds.