• Journal of Environmental Health Sciences
• /
• v.37 no.4
• /
• pp.279-288
• /
• 2011

Objectives: This study investigated the levels and components of floor-settled dust in two elementary schools located at different sites (one near the Shihwa industrial complex and the other in a rural area) in order to evaluate the amounts of trace metal elements (As, Cd, Co, Cr, Cu, Ni, Pb and Zn) and microorganisms. Methods: Over twenty settled-dust samples were collected from the two elementary schools. Trace metal elements were extracted from the dust using hydrochloric acid and nitric acid, and the amounts were measured by ICP-OES. Microbiological analysis was performed by bacterial culturing using R2A medium and denaturing gradient gel electrophoresis (DGGE). Results: The results showed that the amounts of three metal elements (Cr, Pb, and Zn) were significantly different between the schools (${\alpha}$=0.05, p<0.04). In addition, microbial communities in each school were highly correlated with one another. Among the identified microorganisms, a number of potentially opportunistic microorganisms, including antibiotic-resistant bacteria such as Acinetobacter baumannii, were found. Conclusions: This study will provide preliminary data for assessing levels and types of chemical and microbiological agents in elementary schools and for further evaluating human health risks associated with the agents.

• Journal of Mushroom
• /
• v.16 no.3
• /
• pp.225-230
• /
• 2018

This study was conducted to reuse spent mushroom substrates (SMS) of Pleurotus ostreatus and improve their nitrogen content by bacterial treatment. Two kinds of bacteria were used to investigate the increase in total nitrogen (T-N) content. Bacillus sp. (GM20-4) was isolated from SMS of oyster mushroom, and Rhodobacter sphaeroides (RS) was obtained from Gwangju Si Agricultural Technology Center. SMS samples were collected from three oyster mushroom cultivation farms located in Gyeonggi-do province, Korea. When dried SMS was inoculated with 30% culture broth of GM20-4 and RS and incubated at room temperature ($25{\pm}2^{\circ}C$) for 5 days, T-N content increased. To investigate the T-N content of other SMS, three dried SMS samples (A, B, and C) were treated by the same method using GM20-4 and RS. As a result, the T-N content of sample B was 20% higher than that of the control, whereas the T-N content of samples A and C increased to 17% and 12%, respectively. The change in T-N content by bacterial treatment of wet SMS was slightly higher than that of the control. The changes in amino acid content were also found to be higher than those in the control in all SMS samples by GM20-4 and RS treatment. Aspartic acid and glutamic acid contents were the highest among all amino acid compositions. Especially, the aspartic and glutamic acid contents of sample B increased by 2.9 folds higher than the control.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.5
• /
• pp.2139-2144
• /
• 2012

Objective: Gastric cancer remains a major health problem in China. We hypothesized that XRCC1 Arg194Trp and ADPRT Val762Ala may be associated with risk. Methods: We designed a multicenter 1:1 matched case-control study of 307 pairs of gastric cancers and controls between October 2010 and August 2011. XRCC1 Arg194Trp and ADPRT Val762Ala were sequenced, and demographic data as well as lifestyle factors were collected using a self-designed questionnaire. Results: Individuals carrying XRCC1 Trp/Trp or Arg/Trp variant genotype had a significantly increased risk of gastric cancer (OR, 1.718; 95% CI, 1.190-2.479), while the OR for ADPRT Val762Ala variant genotype (Ala/Ala or Val/Ala) was 1.175 (95% CI, 0.796-1.737). No gene-gene or gene-environment interactions were found. In addition, family history of cancer and drinkers proportion were higher among cases than among controls (P<0.05). Conclusions: XRCC1 194 Arg/Trp or Trp/Trp genotype, family history of cancer, and drinking are suspected risk factors of gastric cancer from our study. Our findings may offer insight into further similar large gene-environment and gene-gene studies in this region.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.38 no.5
• /
• pp.291-297
• /
• 2005

This study evaluated the quality of commercial extruded pellet (EP) diet of five companies (A, B, C, D and E) for olive flounder Paralichtys olivaceus by biochemical analyses, physical properties and growth performance. The proximate analyses of five EP diets showed $3.2-10.0\%$ of moisture, $49.3-55.5\%$ of crude protein, $4.6-14.7\%$ of crude lipid, $7.0-13.8\%$ of crude ash, $0.7-10.5\%$ of crude fiber, $10.0-27.3\%$ of itrogen free extract (NFE), 304.3-395.4kcal/100g of digestible energy (DE) and 6.1-7.1 of calorie/protein ratio (C/P). Peroxide value (POV) was highest in diet D (47.4 meq/kg) as compared to other diets which in the range of 4.0-11.7 meq/kg. Total amino acid contents were ranged from 46.54 to $55.46\%$ with the highest content in diet B and the lowest content in diet C. Essential amino acid of diet C was lowest $(7.43\%)$ as compared to other diets which in the range of $19.43-20.30\%$. Saturated fatty acid was higher in diet A $(37.65\%)$ followed by diet B $(36.32\%)$, diet E$(34.39\%)$, diet C$(30.95\%)$ and diet D$(30.10\%)$. EPA+DHA were highest in diet E$(30.78\%)$ and lowest in diet C$(15.48\%)$. The floating rate after 6 hours on the sea water was highest in diet C$(100\%)$ followed by diet B$(40\%)$ and A$(10\%)$. However, diets D and E were completely settled down after 1 and 2 hours, respectively. The range of relative expansion rate was $27.2-49.3\%$ for all diets and all reached the peak at 2-3 hours. The water absorption rate of diets C and D was lowest, and diet E was highest at 1 hour after deposition of sea water. Growth rate was higher in diet B$(22.3\%)$ and E$(21.3\%)$. Feed efficiency was higher in diet A$(109.7\%)$ and E$(105.3\%)$ and was significantly lowest in diet D$(80.7\%)$. The protein efficiency ratio was highest in diet E (2.72) and lowest in diet D (1.76). These results suggest that there is a necessity for improvement of nutrients balance and feed physical properties to fulfill the nutrient requirements and digestive characteristics of fishes in commercial EP diets.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.49 no.4
• /
• pp.427-435
• /
• 2016

The effects of salt solution and chlorella on the quality of canned oyster, Crassostrea gigas, were evaluated to obtain basic data regarding the processing of two canned oyster products. In canned oyster processing, the shucked oyster meat was steamed for 20 min and then drained. Then, each can (301-3) was filled with 90 g boiled oyster in 60 mL 1.5% salt solution for the control samples or 30 mL 1.5% salt solution and 30 mL chlorella culture medium for the experimental samples. All canned products were sealed using a vacuum seamer and then sterilized to Fo values of 6-12 min in a steam retort system at 118℃. The viable bacteria count, proximate composition, pH, salinity, yield, volatile basic nitrogen (VBN), amino-nitrogen, thiobarbituric acid (TBA), mineral, color value, free amino acid levels, hardness, and sensory evaluation of the two canned products were measured under various sterilization conditions. There were no significant differences in the physical or chemical factors and little difference in the overall acceptance of the control and experimental samples.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.49 no.3
• /
• pp.293-300
• /
• 2016

In the present study, we investigated the quality, sensory characteristics and commercialization potential of a rice collet snack made with the addition of dried shrimp. “Mild” and “spicy” snack products were produced with an edible oil coating and mixed seasoning powder coating, respectively. The approximate composition of the mild and spicy snacks, respectively, were 2.44% and 2.24% for moisture, 8.52% and 8.64% for crude protein, 18.36% and 26.54% for crude lipids, 1.28% and 1.38% for ash, 1.1% and 1.2% for salt, and 0.61 and 0.62 for pH. The L (lightness), a (redness), b (yellowness), and ⊿E (color difference) values were higher for the mild snack than the spicy snack. The mild and spicy snack had values of 7,776.4 and 7,655.8 mg/100 g for total amino acids, and 221.6 and 253.5 mg/100 g for total free amino acids, respectively. The TBA (thiobarbituric acid) value did not differ significantly between the two types of snack. The hardness value of the spicy snack was higher than that of the mild snack, but there were no significant differences in flavor between the two products. The sensory evaluation score of the spicy snack was slightly higher than that of the mild snack. Organoleptic inspection indicated that both snacks had a favorable, unique taste.

• Journal of Korean Society of Forest Science
• /
• v.97 no.1
• /
• pp.53-60
• /
• 2008

This study was carried out to investigate the optimum management system during a overwintering for the production of Pinus densiflora container 2-0 seedlings. The experiment performed between 2005~2006 in a polyethylene film house (PE house) located at Yeoju-Gun in Kyungki-Do. During the winter in the PE house, the difference in maximum day temperature and minimum day temperature was large, and the difference in temperature was detected between the container keeping locations. During the winter season, the maximum day temperatures at the seedling bench in January and February were $32.8^{\circ}C$ and$36.6^{\circ}C$, respectively, whereas those at the ground in January and February were $16.0^{\circ}C$ and $24.4^{\circ}C$, respectively. Water contents of container seedlings was reduced gradually from the beginning the experiment, and reduced rapidly from February to March, and increased rapidly from April. Container seedlings showed different death rate according to the extending of the irrigation cycle. Death rate by one week and two weeks of irrigation cycle was 4.8% and 6.5%, and 38.5% and 49.4% of death rate occurred by three and four weeks of irrigation cycle, respectively. It is suggested that the proper irrigation cycle for P. densiflora 2-0 container seedlings during overwintering is two weeks. When containers placed directly on the ground, the root of container seedlings went out through the drainage of the container, and grew out in the soil. These roots were cut while moving the container to the bench in spring.

• IMMUNE NETWORK
• /
• v.10 no.6
• /
• pp.219-229
• /
• 2010

Background: N-myc downstream regulated gene 2 (NDRG2) is a member of the NDRG gene family. Our previous report indicated a possible role for NDRG2 in regulating the cytokine, interleukin-10 (IL-10), which is an important immunosuppressive cytokine. Several pathways, including p38-MAPK, NF-${\kappa}B$, and JAK/STAT, are used for IL-10 production, and the JAK/STAT pathway can be inhibited in a negative feedback loop by the inducible protein, SOCS3. In the present study, we investigated the effect of NDRG2 gene expression on IL-10 signaling pathway that is modulated via SOCS3 and STAT3. Methods: We generated NDRG2-overexpressing U937 cell line (U937-NDRG2) and treated the cells with PMA to investigate the role of NDRG2 in IL-10 production. U937 cells were also transfected with SOCS3- or NDRG2-specific siRNAs to examine whether the knockdown of SOCS3 or NDRG2 influenced IL-10 expression. Lastly, STAT3 and SOCS3 induction was measured to identify the signaling pathway that was associated with IL-10 production. Results: RT-PCR and ELISA assays showed that IL-10 was increased in U937-mock cells upon stimulation with PMA, but IL-10 was inhibited by overexpression NDRG2. After PMA treatment, STAT3 phosphorylation was decreased in a time-dependent manner in U937-mock cells, whereas it was maintained in U937-NDRG2 cells. SOCS3 was markedly reduced in U937-NDRG2 cells compared with U937-mock cells. IL-10 production after PMA stimulation was reduced in U937 cells when SOCS3 was inhibited, but this effect was less severe when NDRG2 was inhibited. Conclusion: NDRG2 expression modulates SOCS3 and STAT3 activity, eventually leading to the inhibition of IL-10 production.

• Journal of the Korean Vacuum Society
• /
• v.17 no.1
• /
• pp.67-72
• /
• 2008

We have studied the effect of heat treatment of multi-walled carbon nanotubes (MWNTs) as a counter electrode on the electro-chemical properties of dye-snsitized solar cells. MWNTs on the p-type Si substrate were synthesized by thermal chemical vapor deposition (CVD) using Fe catalysts. We prepared the two types of MWNTs samples with the different diameters. The rapid thermal annealing (RTA) treatment for the MWNTs was carried out at the growth temperature ($900^{\circ}C$) for 1 minute with $N_2$ gas atmosphere. The structural, electrical and electrochemical properties of MWNTs were investigated by field-emission scanning electron microscopy (FE-SEM), Raman spectroscopy, 2-point probe station and electrochemical impedance spectroscopy (EIS). The I(D)/I(G) ratio of heat-treated MWNTs in Raman spectra was considerably decreased. It was also found that the heat-treated MWNTs showed better redox reaction of iodide at the interface between MWNTs surface and electrolyte than that of as-grown MWNTs. The redox resistance value of heat-treated electrodes was measured to be much lower than that of as-grown electrode at the interface. As a result, the counter electrode using the heat-treated MWNTs showed better electrochemical properties.

• Economic and Environmental Geology
• /
• v.36 no.5
• /
• pp.365-374
• /
• 2003

Various deleterious chemicals can be introduced to existing concrete structures from various external sources. The deterioration of concrete by seawater attack is involved in complex processes due to various elements contained in seawater. In the present study, attention was paid to the formation of secondary minerals and characteristics of mineralogical and micro-structural changes involved in concrete deterioration caused by the influence of major seawater composition. The characteristics of deterioration occurred in existing concrete structures was carefully observed and samples were collected at many locations of coastal areas in Busan-Kyungnam. The petrographic, XRD, SEM/EDAX analyses were conducted to determine chemical, mineralogical and micro-structural changes in the aggregate and cement paste of samples. The experimental concrete deteriorations were performed using various chloride solutions (NaCl, CaCl, $MgCl_2$ and $Na_2SO_4$ solution. The experimental results were compared with the observation results in order to determine the effect of major elements in seawater on the deterioration. The alkalies in seawater appear to accelerate alkali-silica reaction (ASR). The gel formed by ASR is alkali-calcium-silica gel which known to cause severe expansion and cracking in concrete. Carbonation causes the formation of abundant less-cementitious calcite and weaken the cement paste. Progressive carbonation significantly affects on the composition and stability of some secondary minerals. Abundant gypsum generally occurs in concretes subjected to significant carbonation, but thaumasite ({$Ca_6/[Si(OH)_6]_2{\cdot}24H_2O$}${\cdot}[(SO_4)_2]{\cdot}[(CO_3))2]$) occurs as ettringite-thaumasite solid solution in concretes subjected to less significant carbonation. Experimentally, ettringite can be transformed to trichloroaluminate or decomposed by chloride ingress under controlled pH conditions. Mg ions in seawater cause cement paste deterioration by forming non-cementitious brucite and magnesium silicate hydrate (MSH).