• Analytical Science and Technology
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• 제27권5호
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• pp.243-247
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• 2014

Formaldehyde is defined as carcinogen causing leukaemia, lymphoma or nasopharyngeal carcinoma at high level of exposure. Furniture-manufacturing workers can be exposed to formaldehyde, which implies serious impact on health of the workers. The authors carried out ambient monitoring of formaldehyde in the field, and identified the source of formaldehyde generated during the working process by testing the condition in the laboratory settings. After sampling formaldehyde in the air with 2,4-DNPH (2,4-dinitrophenylhydrazine) coated silica gel, we extracted formaldehyde derivative with acetonitrile and analyzed the extract using HPLC with UV detector at 360 nm. Formaldehyde was separated by ACQUITY UPLC BEH $C_{18}$ column at a flow rate of 0.5 mL/min using 45% acetonitrile as mobile phase. The workers were exposed to higher level of formaldehyde than normal air. Formaldehyde up to 0.31 ppm was detected in the process of veneer attachment, which exceeded 0.3 ppm, the ceiling value of ACGIH standard. The laboratory test of measuring formaldehyde generated from the glue and veneer used in the attachment process resulted in more formaldehyde generation as the temperature increased, and more from the veneer. Heating the veneer to $100-150^{\circ}C$ following the real condition of the manufacturing site generated 1.14-2.70 ppm of formaldehyde from the sample, which was 2-5 times higher level than Korean limit of exposure (0.5 ppm). As the workers handling and processing the veneer which was produced by wet process had high possibility to be exposed to formaldehyde, urgent improvement and management of working environment of furniture manufacturer is demanded.

• The Korea Journal of Herbology
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• 제25권2호
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• pp.129-136
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• 2010

Objective : Sinapis alba L. (SA) is a korean traditional herbal medicine that is usually used to prevent or treat inflammatory diseases, such as respiratory infection and rheumatoid arthritis. However, the effects of SA supplementation in vitro on serum antibody levels, splenocyte and peritoneal macrophage immune responses have not yet been determined. In this study, we examined the effect of SA on the production of Th1/Th2 cytokines. Methods : Splenocytes were isolated from naive C57BL/6 mice. Cells were enriched for CD4+ cell populations by first staining the cells with anti-CD4 (BD PharMingen, Calif, USA). CD4+ T cells were selected on a (CS) column, and the flow-through was collected as CD4+ T cells. Isolated cells were activated by overnight incubation on 24-well plates coated with $1{\mu}g/mL$ anti-CD3, $1{\mu}g/mL$ anti-CD28 and with SA ($100{\mu}g/mL$). Primary macrophages were collected from the peritoneal cavities of mice (8-week-old female C57BL/6). The peritoneal macrophages were washed and plated with RPMI-1640 overnight for the experiments. After 48-hours cultures, samples were centrifuged at 2000 rpm for 10 minutes, and the supernatants were stored at $-80^{\circ}C$. Mouse IL-4, IFN-$\gamma$ and TNF-$\alpha$ were quantified using ELISA kits (BioSource International, Camarillo, Calif, USA) according to the manufacturer's protocols. Results : SA at 100ug/ml decreased the generation of Th1 cytokine (IFN-$\gamma$) by 0.5-fold. However, SA has no effect on Th2 (IL-4) production. Conclusions : These results suggest that SA may play an important role in the control of T-cell-mediated autoimmunity by down-regulation of Th1 cytokine (especially IFN-$\gamma$, TNF-$\alpha$). These data may contribute to the design of new immunomodulating treatments for a group of autoimmune diseases.

• The Bulletin of The Korean Astronomical Society
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• 제44권1호
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• pp.42.1-42.1
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• 2019

We observed 80 dense cores ($N(H_2)$ > $10^{22}cm^{-2}$) in the Orion molecular cloud complex which contains the Orion A (39 cores), B (26 cores), and ${\lambda}$ Orionis (15 cores) clouds. We investigate the behavior of the different molecular tracers and look for chemical variations of cores in the three clouds in order to systematically investigate the effects of stellar feedback. The most commonly detected molecular lines (with the detection rates higher than 50%) are $N_2H^+$, $HCO^+$, $H^{13}CO^+$, $C_2H$, HCN, and $H_2CO$. The detection rates of dense gas tracers, $N_2H^+$, $HCO^+$, $H^{13}CO^+$, and $C_2H$ show the lowest values in the ${\lambda}$ Orionis cloud. We find differences in the D/H ratio of $H_2CO$ and the $N_2H^+/HCO^+$ abundance ratios among the three clouds. Eight starless cores in the Orion A and B clouds exhibit high deuterium fractionations, larger than 0.10, while in the ${\lambda}$ Orionis cloud, no cores reveal the high ratio. These chemical properties could support that cores in the ${\lambda}$ Orionis cloud are affected by the photo-dissociation and external heating from the nearby H II region. An unexpected trend was found in the $[N_2H^+]/[HCO^+]$ ratio with a higher median value in the ${\lambda}$ Orionis cloud than in the Orion A/B clouds than; typically, the $[N_2H^+]/[HCO^+]$ ratio is lower in higher temperatures and lower column densities. This could be explained by a longer timescale in the prestellar stage in the ${\lambda}$ Orionis cloud, resulting in more abundant nitrogen-bearing molecules. In addition to these chemical differences, the kinematical difference was also found among the three clouds; the blue excess, which is an infall signature found in optically thick line profiles, is 0 in the ${\lambda}$ Orionis cloud while it is 0.11 and 0.16 in the Orion A and B clouds, respectively. This result could be another evidence of the negative feedback of active current star formation to the next generation of star formation.

• Journal of the Korean Society of Food Science and Nutrition
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• 제24권2호
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• pp.183-194
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• 1995

The purpose of this study was to investigate the effect of vitamin E on the synthesis of the metallothionein in the liver of streptozotocin (STZ)-induced diabetic rats. Sprague-Dawley male rats($220{\pm}10mg$) were randomly assigned to one control and three STZ-diabetic groups. Diabetic groups were classified to STZ-0E(vitamine E free diet), STZ-40E(40mg vitamin E/kg of diet) and STZ-400E(400mg vitamin E/kg of diet) according to the level of vitamin E supplementation. Blood glucose levels of STZ-diabetic rats were three times higher than that of control. The contents of vitamin E in liver were lower signifciantly STZ-0E, STZ-40E groups by 50%, 36% compared with that of control. Lipid peroxide values(LPO) in liver were higher 5.6 and 2.5 times in STZ-0E and STZ-40E groups than that of control. Plasma cortisol levels were higher STZ-0E and STZ-40E groups compared with those of control, but cortisol levels were lower significantly in STZ-400E group compared with those of the STZ-0E and the STZ-40E groups. The plasma insulin levels were lower in all three STZ-diabetic group compared with that of control, but were not affected by the level of dietary vitamin E. The metallothionein (MT) contents in liver, kidney and small intestine were five times higher in STZ-0E, STZ-40E and STZ-400E compared with that of control, but STZ-400E group was lower in the MT contents in tissues compared with that of STZ-40E group. Zn-MT peak in STZ-diabetic rats liver increased than that of control by Sephadex G-75, and Zn-MT peak divided into MTI and MTII peaks by DEAE Sephadex A-25 column chromatography. The present results indicate that STZ-induced diabetic rats are more sensitive to oxidative stress, leading to the acceleration of lipid peroxidation process, which can be more promoted low level of dietary vitamin E. And the result may that increase synthesis of MT induced in the liver of diabetic rats increased so it can be sure that the diabetes is one of the MT induce factor by free radical generation. And high vitamin E supplementation reduced total MT contents of liver, kidney and small intestine and the peak of purified Zn-MT. Through the results of these experiments, we can conclude that MT might be the free radical scavenger.

• Korean Journal of Ecology and Environment
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• 제50권1호
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• pp.29-45
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• 2017

This study explored spatiotemporal variability of water quality in correspondence with hydro-meteorological factors in the four stations of Euiam Reservoir located in the upstream region of the North-Han River from May 2012 to December 2015. Seasonal effect was apparent in the variation of water temperature, DO, electric conductivity and TSS during the study period. Stratification in the water column was observed in the near dam site every year and vanished between August and October. Increase of nitrogen nutrients was observed when inflowing discharge was low, while phosphorus increase was distinct both during the early season with increase of inflowing discharge and the period of severe draught persistent. Duration persisting high concentration of Chl-a (>$25mg\;m^{-3}$: the eutrophic status criterion, OECD, 1982) was 1~2 months of the whole year in 2014~2015, while it was almost 4 months in 2013. Water quality of Euiam Reservoir appeared to be affected basically by geomorphology and source of pollutants, such as longitudinally linked instream islands and Aggregate Island, inflowing urban stream, and wastewater treatment plant discharge. While inflowing discharge from the dams upstream and outflow pattern causing water level change seem to largely govern the variability of water quality in this particular system. In the process of spatiotemporal water quality change, factors related to climate (e.g. flood, typhoon, abruptly high rainfall, scorching heat of summer), hydrology (amount of flow and water level) might be attributed to water pulse, dilution, backflow, uptake, and sedimentation. This study showed that change of water quality in Euiam Reservoir was very dynamic and suggested that its effect could be delivered to downstream (Cheongpyeong and Paldang Reservoirs) through year-round discharge for hydropower generation.

• Journal of the Korean GEO-environmental Society
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• 제22권10호
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• pp.21-29
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• 2021

Most concrete gravity-type dams in and out of the country were constructed by column method to control cracks caused by concrete hydration heat generated during construction, resulting in a certain level of leakage after impoundment through various causes, such as contraction joints and construction joints. However, due to the characteristics of concrete structures that shrink and expand according to temperature, concrete dams have vertical joints and drains to allow penetration. PVC waterproof shows excellent effects in completion of the dam, which however increases the possibility of interfacial failure due to different thermal expansion. Other causes of penetration may include problems with quality control during installation, generation of cracks due to heat of hydration of concrete, waterproofing methods, etc. In the case of Bohyunsan Dam in Yeongcheon, North Gyeongsang Province, the amount of drainage in the gallery was checked and underwater, and it was confirmed that there are many penetrations from drainage holes connected to vertical joints, and that some of the PVC waterproofs are not fully operated. As a new method to prevent penetration through vertical joints, D.S.I.M. (Dam Sealing Innovation Method) developed by World E&C was applied to Bohyunsan Dam and checked the amount of drainage in the gallery. As a result of first testing three most leaking vertical joints, the drain in the gallery was reduced by 87% on the average and then applied to the remaining 13 locations, which showed a 83% reduction effect based on the total drain in the gallery. Summing up these results, it was found that D.S.I.M. preventing water leakage from the upstream face is a valid construction method to reduce the water see-through and penetration quantity seen in downstream faces of concrete dams. If D.S.I.M. is applied to other concrete dams at domestic and abroad, it is expected that it will be very effective to prevent water leakage through vertical joints that are visible from downstream faces.