• Asian Pacific Journal of Cancer Prevention
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• 제15권20호
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• pp.8657-8660
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• 2014

Background: Yanting is one of high risk areas for esophageal cancer and the screening program was therefore initiated there. This study was aimed to investigate the dietary behaviors on the risk of esophageal squamous cell carcinoma (ESCC), among the individuals with normal and abnormal esophagus mucosa. Materials and Methods: A frequency matched case-controls study was proposed to estimate the different distribution of dietary behavior between individuals of control, esophagitis and cancer groups. Cancer cases were selected from hospitals. Esophagitis cases and controls were selected from screening population for ESCC. Health workers collected data for 1 year prior to interview, in terms of length of finishing a meal, temperature of eaten food and interval between water boiling and drinking. Chi-square, Kruskal-Wallis tests and unconditional logistic regression model were used to estimate differences and associations between groups. Results: Compared with controls, length of finishing a meal ${\geq}15mins$ was related to a reduced OR for cancer (OR=0.46, 95%CI, 0.22-0.97) and even compared with cases of esophagitis, the OR of cancer was reduced to 0.30 (95%CI, 0.13-0.72). The OR for often eating food at a high temperature was 2.48 (95%CI 1.06, 5.82) for ESCC as compared with controls. Interval between water boiling and drinking of ${\geq}10mins$ was associated with lower risk of cancer: the OR was 0.18 compared with controls and 0.49 with esophagitis cases (p<0.05). Conclusions: Length of eating food ${\geq}15mins$ and interval between water boiling and drinking ${\geq}10mins$ are potentially related to reduced risk of esophageal SCC, compared with individuals with normal and abnormal esophageal mucosa. Recommendations to Yanting residents to change their dietary behaviors should be made in order to reduce cancer risk.

• Journal of Environmental Health Sciences
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• 제29권3호
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• pp.65-71
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• 2003

The injection concentration of corrosion inhibitor increases under the pH 7, temperature of 2$0^{\circ}C$, and alkalinity of 35 mg/l (as CaCO$_3$), the corrosion rate gradually decreased. When the corrosion inhibitor of 10 mg/l is injected, the corrosion rate for carbon steel pipe, galvanized steel pipe, and copper pipe reduces for 37, 66 and 61 % respectively that it is more efficient on galvanized steel pipe and copper pipe. As a result of examination of corrosion rate at pH 6, 7, and 8 when injecting 10 mg/l of corrosion inhibitor under the conditions of 2$0^{\circ}C$ in water temperature and 35 mg/l (as CaCO$_3$) in alkalinity, the efficiency of the corrosion inhibitor increases as the pH increases. For carbon steel pipe, it does not show much a difference with the change of the pH condition, but galvanized steel pipe and copper pipe clearly show the corrosion rate depending on the change of the pH condition. The efficiency of corrosion inhibitor is low as the concentration of residual chlorine is high, but it does not show a great influence at 0.4 mg/l or less. For each pipe type, in the case of carbon steel pipe, the range of increase of corrosion speed following the residual chloride is higher than the other pipe types. In the meantime, the effect following the residual chlorine in copper pipe is low.

• Polymer(Korea)
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• 제39권1호
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• pp.157-164
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• 2015

In this study, we synthesized poly(vinylimidazole-co-trifluoroethylmethacrylate-co-divinylbenzene) (PVTD) copolymer and introduced functional group through quaternization reaction for removing nitrate from drinking water. Also, optimizing conditions (reaction time, reaction temperature and functionalized agents concentration) for introducing the functional group were confirmed. The basic properties such as water uptake, swelling ratio, electrical resistance, ion exchange capacity and anion permselectivity for removing nitrate from drinking water were measured. The optimal values of water uptake, electrical resistance and ion exchange capacity of synthesized anion exchange membrane were 51.2%, $5.4{\Omega}{\cdot}cm^2$, and 1.04 meq/g, respectively.

• Korean Chemical Engineering Research
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• 제44권2호
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• pp.216-226
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• 2006

Total trihalomethanes (THMs), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) that are the major disinfection byproducts (DBPs) are monitored continuously in drinking water in Seoul. Study on characteristics of DBPs is crucial to judge the safety of drinking water in Seoul. Analysis of THMs, haloacetonitriles (HANs), chloral hydrate (CH), and haloacetic acids (HAAs) was carried out in several distribution systems from January 2002 to December 2004. The concentration of THMs was 0.015 mg/L in purified water, 0.019 mg/L in tapwater by direct service, and 0.023 mg/L in tapwater through watertank, respectively. It might be due to the increased contact time with chlorine by a process of the distribution system. And the other DBPs show a tendency to increase in its concentration by a process of the distribution system. Also, in summer, the concentration of DBPs was higher than in spring and winter. It might be due to the higher temperature of water in summer. In all cases, the quantities of detected DBPs were 4-6 times lower than those of regulation limits of drinking water in Seoul. In view of these results, the tapwater in Seoul is good to drink it all the times.

• The Korea Journal of Herbology
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• 제38권2호
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• pp.35-41
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• 2023

Objectives : Washing face is the first step in skin beauty and health. I wanted to study the cleansing effect by using Placenta cp (cold process) soap. The skin condition is greatly influenced by the external environment such as lifestyle, drinking, smoking, and stress etc. I tried to measure the skin change state without environmental factors. Methods : In order to examine the effect before and after washing face under the same conditions, the same water and towel were used in the same place. The skin test was performed before and 10 minutes after washing. As a control group, a case of washing with water and foam cleanser. I compared and analyzed three cases: water washing, F/C (foam cleanser) washing, and Placenta cp soap washing. Results : In the case of water washing, it was significantly reduced in pores and increased in facial temperature. In the case of F/C washing, the facial temperature was significantly increased, but the decrease in moisture. In the case of washing with Placenta cp soap, significant reductions in T-zone and U-zone oil content, reduction in pore size, and increase in facial skin temperature were observed. Conclusion : In the case of Placenta cp soap, it is thought to be suitable for oily skin type, because of significant decrease in T-zone and U-zone oil content. It is thought to have the effect of increasing blood circulation in the facial skin and to reduce pores for oily skin types.

• Journal of Korean Society on Water Environment
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• 제35권6호
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• pp.557-566
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• 2019

Paldang is a river reservoir in the Midwest of Korea, which is a drinking water source for the metropolitan area. Since the Paldang Reservoir is shallow, and has a short hydraulic residence time, its water quality is directly impacted by two incoming rivers, the north Han River (NHR) and the south Han River (SHR). The NHR has different seasonal patterns of water temperature from the SHR because the NHR is greatly impacted by the discharge water from upstream dams. The electrical conductivity (EC) and other material concentrations of the SHR are usually higher than those of the NHR because its basin is limestone-based. The difference in water temperature in the two rivers causes density flow, and the distribution of the EC within the reservoir can be an indicator for monitoring density flow. From the vertical gradient of the EC at the dam site, from spring to fall, it was confirmed that the SHR flowed into the upper layer, and the NHR flowed into the lower layer, and vice versa at other times. The relative difference (RD) of the EC between the upper layer and the lower layer at the dam site was used as an indicator for density flow. The RD of the EC showed a very significant correlation with the RD of total organic carbon (r = 0.70, p < 0.001) and the RD of total nitrogen (r = 0.58, p < 0.01). This relationship is based on the assumption that the difference in electrical conductivity and water quality between the SHR and the NHR is constant. However, in many cases this assumption is inconsistent. Thus, further study is needed on more suitable indicators to evaluate the impact of density flow on water quality.

• Journal of the Korean housing association
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• 제19권1호
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• pp.79-88
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• 2008

Hot water is used by having a wash, dishes, taking tub and drinking water in residential buildings, and the use objective is to raise comfort of human body sense, washing and sterilization effect and so on. Cold & hot water supply system is understanded simpler than HVAC systems relatively, so it is true that pace of performance improvement is slower than other systems for plan and technical development. In this study, the performance evaluations are conducted under the condition of composition ratio by 1:1 for cold & hot water supply manifold system using functionally complex valves such as constant flow regulating valve and 3-way mixing valve in the area of $105.6m^2$ apartment which consist of the largest part of the whole apartment. Also, flow rate related to simultaneous use of faucets and change of hot water temperature are compared with the existing method.

• Journal of Korean Society of Environmental Engineers
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• 제37권7호
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• pp.404-411
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• 2015

In this study, the effects of empty bed contact time (EBCT) and water temperature on the biodegradation of 9 halonitromethanes (HNMs) in biological activated carbon (BAC) process were investigated. Experiments were conducted at three water temperatures ($10^{\circ}C$, $15^{\circ}C$ and $25^{\circ}C$) and three EBCTs (5, 10 and 15 min). Increasing EBCT and water temperature increased the biodegradation efficiency of HNMs in BAC column. Dibromochloronitromethane (DBCNM) and tribromonitromethane (TBNM) showed the highest biodegradation efficiency, but chloronitromethane (CNM) and dichloronitromethane (DCNM) were the lowest. The kinetic analysis suggested a pseudo-first-order reaction model for biodegradation of 7 HNMs at various water temperatures and EBCTs. The pseudo-first-order biodegradation rate constants ($k_{bio}$) of 7 HNMs ranged from $0.0797{\sim}0.7657min^{-1}$ at $10^{\circ}C$ to $0.1245{\sim}1.8421min^{-1}$ at $25^{\circ}C$. By increasing the water temperature from $10^{\circ}C$ to $25^{\circ}C$, the biodegradation rate constants ($k_{bio}$) were increased 1.6~2.4 times.

• Journal of Korean Society on Water Environment
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• 제16권4호
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• pp.469-477
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• 2000

Bisphenol-A (BPA), a known endocrine disruptor, is a main building block of epoxy resin which is widely used as a coating agent in residential water storage tanks. Therefore, BPA leaching from the epoxy resin may have adverse effects on human health. The possibility of BPA leaching from three epoxy resins were tested with a modified KS D 8502 method at 20, 50, 75 and $100^{\circ}C$ in deionized water and the specified test water, respectively. BPA leached to the test water was identified using GC-MS and quantified with GC-FID after a sequential extraction and concentration. The results showed that BPA leaching has occurred in all three samples tested. The quantify of BPA leaching from unit area of epoxy resin coating was in the range of $10.677{\sim}273.120{\mu}g/m^2$ for sample A, 29.737~1734.045 for sample B and 52.857~548.778 for sample C depending on the test temperature, respectively. In general, the amount of BPA leaching increased as the water temperature increases. This result implies a higher risk of BPA leaching to drinking water during a hot summer season. In addition, microbial growth, measured by colony forming units, in epoxy coated water tanks was higher than that in a stainless steel tank suggesting that compounds leaching from epoxy resin may support the growth of microorganisms in a residential water holding tank.

• Journal of Korean Society on Water Environment
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• 제27권4호
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• pp.533-541
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• 2011

Algal blooms have caused problems for drinking water as well as eutrophication. However it is difficult to control algal blooms by current warning manual in rainy season because the algal blooms happen in a few days. The water quality data, which have high correlations with Chlorophyll-a on Daecheongho station, were analyzed and chosen as input data of Artificial Neural Networks (ANN) for training pattern changes. ANN was applied to early forecasting of algal blooms, and ANN was assessed by forecasting errors. Water temperature, pH and Dissolved oxygen were important factors in the cross correlation analysis. Some water quality items like Total phosphorus and Total nitrogen showed similar pattern to the Chlorophyll-a changes with time lag. ANN model (No. 3), which was calibrated by water temperature, pH and DO data, showed lowest error. The combination of 1 day, 3 days, 7 days forecasting makes outputs more stable. When automatic monitoring data were used for algal bloom forecasting in Daecheong reservoir, ANN model must be trained by just input data which have high correlation with Chlorophyll-a concentration. Modular type model, which is combined with the output of each model, can be effectively used for stable forecasting.