• Title/Summary/Keyword: research and development

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Computational Fluid Dynamics Study of Channel Geometric Effect for Fischer-Tropsch Microchannel Reactor (전산유체역학을 이용한 Fischer-Tropsch 마이크로채널 반응기의 채널 구조 영향 분석)

  • Na, Jonggeol;Jung, Ikhwan;Kshetrimayum, Krishnadash S.;Park, Seongho;Park, Chansaem;Han, Chonghun
    • Korean Chemical Engineering Research
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    • v.52 no.6
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    • pp.826-833
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    • 2014
  • Driven by both environmental and economic reasons, the development of small to medium scale GTL(gas-to-liquid) process for offshore applications and for utilizing other stranded or associated gas has recently been studied increasingly. Microchannel GTL reactors have been prefrered over the conventional GTL reactors for such applications, due to its compactness, and additional advantages of small heat and mass transfer distance desired for high heat transfer performance and reactor conversion. In this work, multi-microchannel reactor was simulated by using commercial CFD code, ANSYS FLUENT, to study the geometric effect of the microchannels on the heat transfer phenomena. A heat generation curve was first calculated by modeling a Fischer-Tropsch reaction in a single-microchannel reactor model using Matlab-ASPEN integration platform. The calculated heat generation curve was implemented to the CFD model. Four design variables based on the microchannel geometry namely coolant channel width, coolant channel height, coolant channel to process channel distance, and coolant channel to coolant channel distance, were selected for calculating three dependent variables namely, heat flux, maximum temperature of coolant channel, and maximum temperature of process channel. The simulation results were visualized to understand the effects of the design variables on the dependent variables. Heat flux and maximum temperature of cooling channel and process channel were found to be increasing when coolant channel width and height were decreased. Coolant channel to process channel distance was found to have no effect on the heat transfer phenomena. Finally, total heat flux was found to be increasing and maximum coolant channel temperature to be decreasing when coolant channel to coolant channel distance was decreased. Using the qualitative trend revealed from the present study, an appropriate process channel and coolant channel geometry along with the distance between the adjacent channels can be recommended for a microchannel reactor that meet a desired reactor performance on heat transfer phenomena and hence reactor conversion of a Fischer-Tropsch microchannel reactor.

The Determinants of Health Promoting Behavior of Industrial Workers (산업장 근로자의 건강증진행위와 자아개념 및 건강의 중요성 인식에 관한 연구)

  • Kim, Chung Nam
    • Korean Journal of Occupational Health Nursing
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    • v.7 no.1
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    • pp.5-19
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    • 1998
  • This descriptive-correlational study was conducted to identify the major factors affecting health promoting behaviors. 344 workers who employed in four different manutacturing plants in Taegu and Kyungbuk area were selected by convenience sampling method. Data were collected from April let to April 18th, 1998 by ready structured questionaires. The purpose of this study was to offer the basic data for health promotion theory development and health promotion strategy planning. This study was based on Pender's Health Promotion Model and examined three variables health promoting behavior, self-concept and perceived importance of health. The Life Style and Health Habit Assessment scale(LHHA) developed by Pender(1982).The Self-concept scale developed by Choi(1972) and the Health Value scale developed by Wallston, Maides and Wallston(1980) were used for this study. Data was analyzed by percentage, mean. t-test. ANOVA, Pearson Correlation Coefficient, and Stepwise Multiple Regression. The major findings of this study are as follows ; 1. The average level of health promoting behavior practice was 63.2% and possible range was from 62 to 248 point. The mean score of respondent's positive self-concept was 75.8. 81.4% of respondents put a high priority on the importance of health. 2. There was a significant difference between the practice level in the category of general self care and less amount of working hours per day(P=0.000), less amount of working hours per week(P=0.000). There was a significant difference between the practice level in the category of nutrition and age(0.002), marital status(0.000), working hour per day(0.008), working hours per week(0.001), There was a significant difference between the practice level in the category of nutriton and sex(0.000), age(0.000), marital status(0.025), education level(0.000), working hours per day(0.002), working hours per week(0.006). There was a significant difference between the practice level in the category of sleep and rest and age(0.003), marital status(0.002), working hours per day(0.001), working hours per week(0.001). There was a significant difference between the practice level in the category of stress management and working hours per day(0.001), working hours per week(0.002). There was a significant difference between the practice level in the category of self-actualization and working hours per day(0.050). 3. General characteristics influencing the respodent's self-concept were level(P=0.009) and worksite(P=0.001). 4. The results of the hypothesis tests are as follows The first hypothesis, that "The respondent who have more positive self-concept will have higher scores in the practice of health promoting behavior." was supported(r=0.2973, P=0.0001). The second hypothesis that "The respondent who have higher perception level on importance of health will have higher scores in the practice health promoting behavior." was rejected(r=- 0665, P=0.2225). 5. The most important factor that affects health promoting behavior practice was working hours per week(6.0%). The combination of working hours per week, age, education level accounted for 10.0% of the variance in health promoting behavior. In conclusion, the results of this study on industrial workers supported Pender's health promotion model in partial and showed the relatedness between self concept and the practice of health promoting behavior. Further research is required to find factors influencing health promoting behaviors of industrial workers.

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A Study on the Water Reuse Systems (중수도개발연구(中水道開發研究))

  • Park, Chung Hyun;Lee, Seong Key;Chung, Jae Chul
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.4 no.4
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    • pp.113-125
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    • 1984
  • Water supply has been mainly dependent on the construction of the dams in Korea. It is difficult, however, to continue to construct dams for many reasons, such as the decrease of construction sites, the increase of construction costs, the compensation of residents in flooded areas, and the environmental effects. Water demands have increased and are expected to continue increasing due to the concentration of people in the cities, the rise of the living standard, and rapid industrial growth. It is acutely important to find countermeasures such as development of ground water, desalination, and recycling of waste water to cope with increasing water demands. Recycling waste water includes all means of supplying non-potable water for their respective usages with proper water quality which is not the same quality as potable water. The usages of the recycled water include toilet flushing, air conditioning, car washing, yard watering, road cleaning, park sprinkling, and fire fighting, etc. Raw water for recycling is obtained from drainage water from buildings, toilets, and cooling towers, treated waste water, polluted rivers, ground water, reinfall, etc. The water quantity must be considered as well as its quality in selecting raw water for the recycling. The types of recycling may be classified roughly into closed recycle systems and open recycle systems, which can be further subdivided into individual recycle systems, regional recycle systems and large scale recycle system. The treatment methods of wastewater combine biochemical and physiochemical methods. The former includes activated sludge treatment, bio-disc treatment, and contact aeration treatment, and the latter contains sedimentation, sand filtration, activated carbon adsorption, ozone treatment, chlorination, and membrane filter. The recycling patterns in other countries were investigated and the effects of the recycling were divided into direct and indirect effects. The problems of water reuse in recycle patterns were also studied. The problems include technological, sanitary, and operational problems as well as cost and legislative ones. The duties of installation and administrative organization, structural standards for reuse of water, maintenance and financial disposal were also studied.

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Analysis of the Physicochemical Properties and Antioxidative Activity of Napa Cabbage Pickle (저장기간 동안 배추 피클의 이화학적 특성 및 항산화 활성 분석)

  • Son, Hae-Reon;Oh, Sun-Kyung;Bae, Sang-Ok;Choi, Myeong-Rak
    • Journal of Life Science
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    • v.26 no.11
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    • pp.1275-1281
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    • 2016
  • The principal objective of this fundamental research was to analyze the physicochemical properties the and antioxidative activity of Napa cabbage pickle (NCP) for development of low-salt pickles. NCP-1 was a smaller than NCP at amount soy sauce (10%). The pH of NCP and NCP-1 were $4.51{\pm}0.15$, $4.85{\pm}0.08$ immediately after preparation. The pH of NCP and NCP-1 was reduced to $4.08{\pm}0.05$ and $4.31{\pm}0.12$ over time during 60 days of storage. The acidity of the NCP and NCP-1 immediately after preparation were 0.51% and 0.38% and increased to 0.67% and 0.56% after 60 days of storage. The salinity for the NCP ranged from 1.71-2.22% and NCP-1 ranged from 1.18-1.63%. The L value, which indicates the lightness, was the highest at day 0 and the lowest at 60 day. The tensile strength value of NCP was $10.9{\pm}0.05kgf/cm^2$ and NCP-1 in $11.84{\pm}0.11kgf/cm^2$ at day 0 and then significantly decreased with time in storage. The cutting force of NCP was $1004{\pm}7.12gf/cm^2$ and NCP-1 in $845{\pm}5.27gf/cm^2$ at day 0, which increased over time in storage. The overall acceptability of NCP was the highest at day 30, but the overall acceptability of NCP-1 was the highest at day 45. NCP-1 extracts at day 60 showed the highest antioxidant activity of 66.04%, whereas the NCP extract at day 0 showed the lowest antioxidant activity of 45.41%. These results showed that depending on the content of the seasoning pickle difference in the antioxidant activity. Thus, the best pickled Napa cabbage is determined by a smaller amount soy sauce in NCP-1, and the results could provide a basis for improving the availability and quality of Napa cabbage.

Emission of Greenhouse Gases from Upland Rice and Soybean (밭벼와 콩 재배지의 온실가스 배출)

  • Shin, Yong-Kwang;Ahn, Jong-Woong;Koh, Mun-Hwan;Shim, Jae-Chun
    • Korean Journal of Soil Science and Fertilizer
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    • v.36 no.4
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    • pp.256-262
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    • 2003
  • The emission of methane and nitrous oxide was measured from fields of upland rice and soybean. Rice cultivar, Daejinbyeo, was seeded in a row of 30 cm space in upland soil on April 28, 2001. The fields were irrigated with sprinkler irrigation or natural precipitation. Three soybean cultivars Jangyeobkong, Taekwangkong and Hwangkeumkong, were sown with seeding space of $60{\times}15cm$ on June 16, 2001. Gas samples were collected twice a week during the growth period, and methane and nitrous oxide were analyzed. Methane emission from upland rice field of sprinkler irrigation was $3.5kg\;CH_4\;ha^{-1}$. However, negative emission of methane, $-1.7kg\;CH_4\;ha^{-1}$, was observed in upland rice field of natural precipitation. Total nitrous oxide emission from upland rice field of sprinkler irrigation was $50.8kg\;N_2O\;ha^{-1}$, while the emission in the field of natural precipitation was $8.3kg\;N_2O\;ha^{-1}$. Global warming potentials (GWP) in the upland rice fields of sprinkler irrigation and natural precipitation were 15,822 and $2,216kg\;CO_2\;ha^{-1}$, respectively. Methane emissions from fields of soybean cultivars Jangyeobkong, Taekwangkong and Hwangkeumkong were -14.7, -4.3 and $4.8kg\;CH_4\;ha^{-1}$, respectively. Total nitrous oxide emissions from fields of soybean cultivars Jangyeobkong, Taekwangkong and Hwangkeumkong were 4.7, 4.6 and $3.0kg\;N_2O\;ha^{-1}$, respectively. Total GWPs for soybean cultivars Jangyeobkong, Taekwangkong and Hwangkeumkong were 1152, 1323 and $1027kg\;CO_2\;ha^{-1}$, respectively.

A Study on Visitor Motivation and Satisfaction of Urban Open Space - In the Case of Waterfront Open Space in Seoul - (도시 오픈스페이스 방문동기 및 만족도 연구 - 서울시 하천변 오픈스페이스를 중심으로 -)

  • Zoh, Kyung-Jin;Kim, Yong-Gook;Kim, Young-Hyun
    • Journal of the Korean Institute of Landscape Architecture
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    • v.42 no.1
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    • pp.27-40
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    • 2014
  • The functions of urban open space, which embraces community revitalization, are diverse. It is the means of public healthcare, learning centers for children, hub of arts and cultural programs, as well as promoter of urban tourism. However, in-depth discourse and research on the topic of urban open spaces has been limited so far. Hence, this study aims to investigate the motivations and satisfaction of visitation based on four representative waterfront open space in Seoul; Cheongyecheon Waterfront, Seoul Forest Park, Seonyudo Park and Banpo Hangang Park. The methods of study are literature review, observation investigation, and questionnaire survey. The findings are analyzed through the Exploratory Factor Analysis, Reliability Analysis, ANOVA Analysis and Regression Analysis by SPSS 18.0. The results of the study are as follows. First, urban waterfront open spaces in Seoul has 5 factors of visitor motivation; community amenity, nature access, cultural and educational assets, aesthetic enjoyment, and lastly means of escape. Second, factors of recognizing urban waterfront open spaces as community amenity and nature access indicate meaningful differences in visitor's perception by spatial characteristics. Third, distances between the destination and the visitor's residence influence significantly their perceived motivation. Close-range visitors perceived nature access as a principal factor, whilst medium to long-range visitors perceived visitation for aesthetic purposes more importantly. Lastly, the will to escape was shown as the influential factor in visitor satisfaction. Visiting open spaces for the enjoyment of nature and aesthetic purposes were factors that also closely relate to visitor satisfaction. In addition, it was found that there are different visitor motivations that influence visitor satisfaction in accordance with the spatial characteristics of each open space. In summary, it can be said that urban waterfront open space is a hybrid space connected to various types of urban contents beyond daily experiences. It was found that several visitor motivations including community development, design aesthetics, education and culture, entertainment, enjoyment of natural landscape, and relaxation, affect the overall satisfaction of the visiting experience. It is anticipated that the results of the study will be used by the local government in setting up strategies for the creation and management of successful urban waterfront open space, and for those involved in planning and design act as a starting point for spatial programming and amenities arrangement in accordance to the city's tourism and urban marketing approach.

Practical Strategies for Urban Regeneration through an Application of Landscape Urbanism (랜드스케이프 어바니즘 관점에서 본 도시재생 전략 연구)

  • Cho, Se-Hwan
    • Journal of the Korean Institute of Landscape Architecture
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    • v.38 no.2
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    • pp.109-118
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    • 2010
  • This study aims to propose practical strategies for the new urban ideal of regeneration. A book review highlights the emergence of new trends of urbanization in knowledge-information industrial society beyond the new town Ideal of the industrial society. The meaning of ‘landscape’ in landscape urbanism represents not the visual and decorative pictures, but the dynamic process in the context of changes and evolutions. Also, knowledge-information industrial society and landscape have a meaning in the same context of flow and process with changes of velocity. Finally, these key words convey a meaning with the new urban trends of urbanization in knowledge-information industrial society in the context of value-oriented characteristics of dynamics and process. Urban regeneration is emerging as the new urban ideal in the knowledge-information industrial society, beyond the new town ideal of industrial society. It is in the same context as landscape urbanism with respect to green infrastructure buildings and designs for the transformation of urban surfaces covered with concrete and asphalt into the ecological surface, and of the ecological surfaces into the cultural surface that could be communicated with human beings. This research revealed the six strategies for urban regeneration as follows. The First, the strategies for the transformation of urban surfaces into ecological surfaces, the second, the strategies for the transformation of ecological surfaces into cultural surfaces, the third, the introduction of mixed and convergence land use, the forth, the transformation of former sites(e.g. military and factory) into urban parks, the fifth, the introduction of waterfront park zones that have the function of ecological and park-oriented mixed land use and, the sixth, the building and design of green infrastructure in the residential and commercial complex in CBD. These strategies call for the reforms of development laws and regulations to restrict building coverage ratio, building heights, and the introduction of park-oriented mixed zoning regulations. Another method for implementating the above listed strategies was the introduction of a strategic planning system instead of the traditional master plan system. This system uses a value planning approach and brand making by imagery. It is able to construct the meaning of an image and its creativeness directly.

Influence that Wage Satisfaction of the private Security Guards has on Devotion Organization (민간경비원의 임금만족이 조직몰입에 미치는 영향)

  • Kim, Chan-Sun;Kim, Sang-Jin
    • Korean Security Journal
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    • no.12
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    • pp.89-116
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    • 2006
  • As the society changes, the Private Security has developed highly in a short time. However, it has brought about various problems. The best urgent problem of those problems is the wage problem. This study is examining into the difference with the wage satisfaction and devotion to organization, and analyzing influence that wage satisfaction has on devotion to organization. According to this research, the first, women appeared higher numerical value than men in satisfaction with a wage level, wage disparity, wage system and the welfare system and the highest age group is over 26 year-old. While the college graduates appeared high satisfaction with a wage level and wage disparity, the university graduates is high satisfaction with wage system and the welfare. This shows that as the scholarship is high, they think they must be getting wages higher and higher as their work result or produce. The second, in devotion to his(her) organization, the men is higher than the women. The third, the men show the high emotional devotion because the men devote to his work on his own initiative while the women show the high continuos service devotion because they are passively. The fourth, over the 26-year old group appeared high level in devotion to his(her) organization, the university graduate group appeared high level both the emotional devotion and the continuous service devotion. The long-term employed person showed the satisfaction with job position, pay grade, and career and also appeared high in devotion to his(her) organization. The fifth, as the scholarship is low, they were concerned about a wage level and wage disparity but, as the scholarship is high, they were concerned about the wage system and the welfare. The wage satisfaction has influence on the scholarship, job position and career therefore, the long-term employed persons showed high wage satisfaction and devotion to his(her) organization. In conclusion, for the development of Private Security and high devotion to organization, the wage level of private security guards must be systematize and the quality of the welfare must be improved. And the many factors about the wage and welfare must be studied and analyzed to occupy as one of the skill lists through the educational-industrial collaboration.

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Effect of Development and Application of Teaching-Learning Materials and Plan using Persimmon juice Dyeing on the Traditional Clothing Life-Culture Education (감즙염색을 이용한 학습자료와 교수-학습과정안 개발 및 적용이 전통 의생활문화 교육에 미치는 효과)

  • Park, Soonja;Yoo, Jiyeon
    • Journal of Korean Home Economics Education Association
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    • v.25 no.1
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    • pp.79-94
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    • 2013
  • In this study, the teaching-learning materials and the plan using persimmon juice dyeing, which is one of the traditional natural dyeing methods of Korea, were developed for the purpose of inspiring further awareness of our traditional clothing life-culture. A questionnaire was designed to make a survey on the educational effect, and t-test and Kruscal-Wallis test were conducted to test the significant differences between pre- and post-lessons. A correlation analysis between culture awareness and its education awareness was also done. These prototypes were applied to high school Technology Home Economics classes under the theme, 'Making living goods with persimmon juice dyed fabrics'. Examining the changes in students' awareness of traditional images, and changes in their interest and attitude towards learning in those classes led to the following results. First, as a result of applying LT cooperative learning in order for an understanding of the formation of clothing life-culture and the process of persimmon juice dyeing, many original handicrafts with modern sense were created. Second, a comparative analysis between pre- and post-lessons on the change in students' degree of awareness of traditional clothing life-culture and its education showed that students' awareness had risen after the class; the data was collected from three separate sample groups which had been clustered according to their initial degree of awareness, i.e. high, middle, and low, and the group that scored the lowest before the class showed the greatest improvement. Third, feedback surveys on 'Making living goods with persimmon juice dyed fabrics' classes returned with scores greater than 'moderate', thus revealing that the students' concern and interest towards traditional clothing life-culture hae been enhanced through the class experience. Their attitude had also become more positive. Fourth, since learners with more awareness of the traditional clothing life-culture also showed more awareness of the need for an education designed to promote the culture, a positive correlation between the two had been found. As explained above, the teaching-learning materials and the plan that had been developed for this study has caused a deeper understanding of the value and significance of the traditional natural dyeing and clothing life-culture, and has therefore brought about an educational effect that powers idea creation.

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Interleukin-4 and -8 Gene Polymorphisms and Risk of Gastric Cancer in a Population in Southwestern China

  • Pan, Xiong-Fei;Wen, Ying;Loh, Marie;Wen, Yuan-Yuan;Yang, Shu-Juan;Zhao, Zhi-Mei;Tian, Zhi;Huang, He;Lan, Hui;Chen, Feng;Soong, Richie;Yang, Chun-Xia
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.7
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    • pp.2951-2957
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    • 2014
  • Background: Gastric carcinogenesis is a complicated process that involves environmental and genetic factors like interleukin-4 (IL-4) and IL-8. Single nucleotide polymorphisms in their genes are associated with changed levels of gene expression. Here, we investigated the association between IL4-590 C>T and IL8-251T>A and gastric cancer (GC) risk in Sichuan of Southwestern China. Materials and Methods: We surveyed the research subjects using a self-designed questionnaire with questions on demographic factors and putative risk factors. Approximately 2-5ml of whole blood was collected after field survey to analyze IL4-590 C>T and IL8-251T>A genotypes using MALDI-TOF MS. Results: Our study recruited 308 pairs of GC patients and controls, including 224 (72.7%) men and 84 (27.3%) women in each group. There were 99 cardia and 176 noncardia GC patients in the case group. The case and control groups had an average age of $57.7{\pm}10.6$ ($mean{\pm}SD$) and $57.6{\pm}11.1$ years. GC patients reported a significantly greater proportion of family history of cancer (29.9% vs 10.7%, p<0.01) and drinking (54.6% vs 43.2%, p<0.01) than did controls. Variant genotypes of IL-4-590 C>T and IL-8-251 T>A were not associated with overall GC risk (adjusted OR, 0.89; 95%CI, 0.61-1.28 for CT or CC vs TT; adjusted OR, 1.14; 95%CI, 0.86-1.79 for TA or AA vs TT). Stratification analysis of two SNPs for risk by subsites only found that variant IL-8-251 TA or AA genotype was associated with increased noncardia GC risk (adjusted OR, 2.58; 95%CI, 1.19-5.57). We did not observe interactions between the IL-8-251 T>A genotype and smoking (adjusted OR, 0.38; 95%CI, 0.08-1.79) or drinking (adjusted OR, 0.36; 95%CI, 0.08-1.65) for risk of noncardia GC. Conclusions: Our data indicate no association between the two SNPs of IL-4-590 and IL-8-251 with overall GC risk, while the IL-8-251 TA or AA genotype conferred risk of cardia GC. Our findings contribute to the evidence body for risk of SNPs associated with the development of gastric cancer in this region.