• Title/Summary/Keyword: case-control studies

Search Result 1,587, Processing Time 0.027 seconds

The study on Installation Areas of Permeable Pavement for Stormwater Control (우수유출 저감을 위한 투수성 포장의 설치 면적에 관한 연구)

  • Jang, Young-su;Shin, Hyun-suk
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.18 no.11
    • /
    • pp.104-109
    • /
    • 2017
  • The flooding and deterioration of water quality caused by urbanization and climate change are becoming more serious. In order to respond to this, studies on low impact development (LID) technology, which is designed to restore the hydrological system of the urban basin to its natural state, have been actively pursued all over the world, The announcement of the low carbon green growth law, hydrophilic area special law, etc., highlights the importance of technology such as the LID method. However, whereas various developments have been made in relation to the current LID element technology, there has been little research designed to verify its effectiveness. In this study, we analyzed the optimum spatial distribution of pitcher fire pitcher packing in parking lots using the K - LIDM model to verify the effectiveness of the low impact development (LID) method in the early stages. Using the eight package scenario and the three rain intensity scenarios, it was found that the lower 40% pitcher packaging results in an approximately 90% spill reduction effect, as in the case of the whole pitcher's package. The confirmation of these analyses and experimental verification is expected to ensure that the actual pitcher packaging will be used as a basis for arranging LID facilities such as urban planning and housing development in the future.

Polymorphisms of 5,10-Methylenetetrahydrofolate Reductase (MTHFR C677T and A1298C) Gene in Recurrent Spontaneous Abortion (5,10-Methylenetetrahydrofolate Reductase (MTHFR C677T와 A1298C) 유전자 돌연변이의 반복자연유산 관련성 연구)

  • Kim, Nam-Keun;Nam, Yoon-Sung;Lee, Su-Man;Kim, Sun-Hee;Shin, Seung-Joo;Chang, Sung-Woon;Kim, Se-Hyun;Cha, Kwang-Yul;Oh, Do-Yeun
    • Clinical and Experimental Reproductive Medicine
    • /
    • v.29 no.3
    • /
    • pp.215-222
    • /
    • 2002
  • Objective : Previous studies have suggested that hyperhomocysteinemia and methylenetetrahydrofolate reductase (MTHFR C677T) mutations are associated with increased risk of recurrent spontaneous abortion (RSA). Recently, a second site polymorphism in MTHFR, 1298A-->C, which changes a glutamic acid into an alanine residue, was shown to be associated with a decreased enzyme activity. We tested whether the variant alleles of MTHFR C677T and A1298C are risk factor (biomarker) for RSA. Materials and Methods: We analyzed DNA from a case-control study in the Korean DNA was extracted from blood samples of 118 patients with RSA and 123 healthy fertile patients as the controls. MTHFR variant alleles were determined by a PCR-restriction fragment length polymorphism assay. Results: We found no evidence for an association between 677TT genotype and risk of RSA (OR=1.95, 95% CI=$0.84{\sim}4.50$, p=0.12). However, the MTHFR 1298AC (OR=0.36, 95% CI=$0.20{\sim}0.63$, p=0.0004) and 1298AC+CC (OR=0.35, 95% CI=$0.20{\sim}0.61$, p=0.0002) genotypes were lower among 118 RSA cases compared with 123 controls, conferring a 2.8-fold decrease in risk of RSA, respectively. Moreover, the combined genotypes of MTHFR 677CC/1298AC (OR=0.30, 95% CI=$0.10{\sim}0.88$, p=0.029) and 677CT/1298AC (OR=0.77, 95% CI=$0.60{\sim}0.99$, p=0.043) also showed significantly lower risk than those with MTHFR 677CC/1298AA type. Conclusion: MTHFR 1298AC, MTHFR 677CC/1298AC and 677CT/1298AC genotypes may represent genetic markers for the protection of RSA at least in Korean women.

Behaviour of steel-fibre-reinforced concrete beams under high-rate loading

  • Behinaein, Pegah;Cotsovos, Demetrios M.;Abbas, Ali A.
    • Computers and Concrete
    • /
    • v.22 no.3
    • /
    • pp.337-353
    • /
    • 2018
  • The present study focuses on examining the structural behaviour of steel-fibre-reinforced concrete (SFRC) beams under high rates of loading largely associated with impact problems. Fibres are added to the concrete mix to enhance ductility and energy absorption, which is important for impact-resistant design. A simple, yet practical non-linear finite-element analysis (NLFEA) model was used in the present study. Experimental static and impact tests were also carried out on beams spanning 1.3 meter with weights dropped from heights of 1.5 m and 2.5 m, respectively. The numerical model realistically describes the fully-brittle tensile behaviour of plain concrete as well as the contribution of steel fibres to the post-cracking response (the latter was allowed for by conveniently adjusting the constitutive relations for plain concrete, mainly in uniaxial tension). Suitable material relations (describing compression, tension and shear) were selected for SFRC and incorporated into ABAQUS software Brittle Cracking concrete model. A more complex model (i.e., the Damaged Plasticity concrete model in ABAQUS) was also considered and it was found that the seemingly simple (but fundamental) Brittle Cracking model yielded reliable results. Published data obtained from drop-weight experimental tests on RC and SFRC beams indicates that there is an increase in the maximum load recorded (compared to the corresponding static one) and a reduction in the portion of the beam span reacting to the impact load. However, there is considerable scatter and the specimens were often tested to complete destruction and thus yielding post-failure characteristics of little design value and making it difficult to pinpoint the actual load-carrying capacity and identify the associated true ultimate limit state (ULS). To address this, dynamic NLFEA was employed and the impact load applied was reduced gradually and applied in pulses to pinpoint the actual failure point. Different case studies were considered covering impact loading responses at both the material and structural levels as well as comparisons between RC and SFRC specimens. Steel fibres were found to increase the load-carrying capacity and deformability by offering better control over the cracking process concrete undergoes and allowing the impact energy to be absorbed more effectively compared to conventional RC members. This is useful for impact-resistant design of SFRC beams.

Study Gene Interaction Effect Based on Expanded Multifactor Dimensionality Reduction Algorithm (확장된 다중인자 차원축소 (E-MDR) 알고리즘에 기반한 유전자 상호작용 효과 규명)

  • Lee, Jea-Young;Lee, Ho-Guen;Lee, Yong-Won
    • The Korean Journal of Applied Statistics
    • /
    • v.22 no.6
    • /
    • pp.1239-1247
    • /
    • 2009
  • Study the gene about economical characteristic of human disease or domestic animal is a matter of grave interest, preserve and elevation of gene of Korea cattle is key subject. Studies have been done on the gene of Korea cattle using EST based SNP map, but it is based on statistical model, therefore there are difference between real position and statistical position. These problems are solved using both EST_based SNP map and Gene on sequence by Lee et al. (2009b). We have used multifactor dimensionality reduction(MDR) method to study interaction effect of statistical model in general. But MDR method cannot be applied in all cases. It can be applied to the only case-control data. So, method is suggested E-MDR method using CART algorithm. Also we identified interaction effects of single nucleotide polymorphisms(SNPs) responsible for average daily gain(ADG) and marbling score(MS) using E-MDR method.

Studies on the Salt Movement of Upland Soil in Reclaimed Tidal Land (간척지(干拓地) 밭토양(土壤)의 염류이동(鹽類移動)에 관(關)한 연구)

  • Lee, Jong-Sik;Kim, Jong-Gu;Yoo, Chul-Hyun;Kang, Jong-Gook;Kim, Ho-Jung
    • Korean Journal of Soil Science and Fertilizer
    • /
    • v.24 no.1
    • /
    • pp.28-34
    • /
    • 1991
  • This study was carried out to investigate the salt movement in upland soils in reclaimed region (Kye-Hwa Do). The results obtained were summarized as follows : 1. The cation content in ground water increased during time course. but in the case of land-surface water the content was variable, and $K^+$ was lower than that of $Na^+$ and $M^{+2}$. At the L. S. P(Low salinity plot) under rainproof condition, the salinity was directly proportional to soil water content, but at the H. S. P (High salinity plot) the tendency was no reversed. 3. In condition of rainproof, the amount of available phosphorous was higher at the H. S. P than at the L. S. P. 4. Positive correlation was obtained between the soil water content and available phosphorous content at the rainfall plot, but there was no significance at the surface soil of the rainproof plot. 5. SAR (Sodium adsorption ratio) and anion ($Cl^-$, $SO_4{^{2-}}$) contents in soil were repressed in the order of black vinyl>white vinyl>rice straw>control.

  • PDF

The Comparison of Various Turbulence Models of the Flow around a Wall Mounted Square Cylinder (벽면에 부착된 사각 실린더 주변 유동에 대한 난류모델 비교연구)

  • Bae, Jun-Young;Song, Gi-Su
    • Journal of the Korean Society of Marine Environment & Safety
    • /
    • v.26 no.4
    • /
    • pp.419-428
    • /
    • 2020
  • The flow past a wall mounted square cylinder, a typical and basic shape of building, bridge or offshore structure, was simulated using URANS computation through adoption of three turbulence models, namely, the k-ε model, k-ω model, and the v2-f model. It is well known that this flow is naturally unstable due to the Karman vortex shedding and exhibits a complex flow structure in the wake region. The mean flow field including velocity profiles and the dominant frequency of flow oscillation that was from the simulations discussed earlier were compared with the experimental data observed by Wang et al. (2004; 2006). Based on these comparisons it was found that the v2-f model is most accurate for the URANS simulation; moreover, the k-ω model is also acceptable. However, the k-ε model was found to be unsuitable in this case. Therefore, v2-f model is proved to be an excellent choice for the analysis of flow with massive separation. Therefore, it is expected to be used in future by studies aiming to control the flow separation.

Case Report : Treatment of Burning mouth Syndrome Using a Removable Anti-Nociceptive Appliance (가철성 유해자극차단장치를 이용한 구강작열감증후군의 치료 증례)

  • Roh, Byung-Yoon;Ahn, Jong-Mo;Yoon, Chang-Lyuk;Ryu, Ji-Won
    • Journal of Oral Medicine and Pain
    • /
    • v.37 no.1
    • /
    • pp.1-7
    • /
    • 2012
  • Burning mouth syndrome(BMS) refers to a chronic orofacial pain disorder usually unaccompanied by mucosal lesions or other clinical signs. Tongue(anterior and lateral border) is found to be the most common site for the burning sensations in the oral cavity, and various oral sites may be affected including hard palate and lips. The etiology of this disorder remains poorly understood, but the various factors might be related with the pathogenesis of the BMS. These factors have been devided into local, systemic and psychological. Recently, there have been increasing reports that the pain of BMS may be neuropathic in origin. The complex and multifactorial etiology of BMS necessitates multidisciplinary approach for the management of these patients. Recently, several studies have reported that oral parafunctional habits could be related the pathogenesis of BMS, and tried to control the symptom of BMS with various methods. We reported the cases who had the symptom of burning mouth syndrome with removable anti-nociceptive appliance in the lower dentition.

Theory of the National Flag Poles As a Hegemonic State Apparatus (태극기 게양대라는 헤게모니 국가장치론 서설)

  • Jeon, Gyu-chan
    • Korean journal of communication and information
    • /
    • v.77
    • /
    • pp.111-136
    • /
    • 2016
  • This paper focuses on the national "flagging" as a current affair, important phenomenon. National flags, it sees, take over varous places, control the surrounding space, and even dictate everybody's perspective by being visualized everywhere anytime. It investigates the issue of national flags and their hoisting poles as a sort of apparatuses that interpellate me as well as us into patriotic 'gookmin'. The placement, arrangement of national flag poles around the country continued throughout 2015 and particularly speeded up in October of the year is regarded as a key symbolic, symptomatic sign to read the transformation of political conjuncture. Preparing a radically conjuncturist cultural study about the changing reality, the researcher will see the flagging poles as a phenomenal result, outcoming of certain intent and plan for reconstructing the political actuality. More precisely, he will interpretate the tall omni-present poles of national flags as a dispositif of appearing the neoliberal/neoconservative capitalist state, as a apparatus of constituting and expressing the masses' psycho-ideological condition of today. The researcher, who perceives the national flag poles as a kind of ISAs. will first review the increased flagging phenomenon and related media discourses. Next, he will critically investigate the 'love our country' 'national flagging' movements organized by the above and operated from the bottom. Then, he will focus more on the very tall national flag poles built and seen around the country. Finally, he will conclude the study with a critical remark, touching briefly the case of controversy over setting a pole in the center of Seoul city square.

  • PDF

Seasonal Occurrence and Age Structure of Paromius exiguus (Distant) (Heteroptera: Lygaeidae) on Major Host Plants (흑다리긴노린재[Paromius exiguus (Distant)](Heteroptera: Lygaeidae)의 발생소장과 주요 기주에서 시기별 연령분포)

  • Park, Chang-Gyu;Park, Hong-Hyun;Uhm, Ki-Baik;Lee, Joon-Ho
    • Korean journal of applied entomology
    • /
    • v.48 no.1
    • /
    • pp.21-27
    • /
    • 2009
  • Paromius exiguus (Distant) has caused serious damage by pecky grains around Gimpo paddy fields in 2001. We conducted field and laboratory studies to determine the seasonal occurrence and age distribution of P. exiguus on the three major host plants. The overwintering P. exiguus was found mainly on the basal part of gramineae weeds in various localities. After overwintering, in mid-May, the adults aggregated on the grain parts of Imperata cylindrica, laid their eggs and nymphs developed into adults on the same host plants. By the time, the Calamagrostis epigeios colony had newly occupied I. cylindrica areas, the nymphs and adults of first generation had already moved to the second host. The second generation of P. exiguus, after having completed its life cycle on C. epigeios, the newly emerged adults migrated to the rice plants and other gramineae weeds in early August. Afterwards, they complete its third generation cycle where they can move to the overwintering site again. P. exiguus has the five nymphal stages and each nymphal stage could be determined by head or prothoracic width. On the I. cylindrica and O. sativa hosts, the age distribution of P. exiguus showed a simple structure as each stage ratio increased stepwise with time. But in case of C. epigeios, as the newly emerged adults and immature nymphs continuously migrate after a month from the I. cylindrica, the age structure became remarkably complex. The peak nymphal density was observed when the ratio of third and forth instar was the highest in the population. The finding about the specific age structure on each generation of the insect would be very useful in control decision making on the major host plants. It is also important to consider the host's specificity to pesticide sensitivity in relation to various nymphal stages.

Folate-Related Nutrients, Genetic Polymorphisms, and Colorectal Cancer Risk: the Fukuoka Colorectal Cancer Study

  • Morita, Makiko;Yin, Guang;Yoshimitsu, Shin-Ichiro;Ohnaka, Keizo;Toyomura, Kengo;Kono, Suminori;Ueki, Takashi;Tanaka, Masao;Kakeji, Yoshihiro;Maehara, Yoshihiko;Okamura, Takeshi;Ikejiri, Koji;Futami, Kitaroh;Maekawa, Takafumi;Yasunami, Yohichi;Takenaka, Kenji;Ichimiya, Hitoshi;Terasaka, Reiji
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.14 no.11
    • /
    • pp.6249-6256
    • /
    • 2013
  • One-carbon metabolism plays an important role in colorectal carcinogenesis. Meta-analyses have suggested protective associations of folate and vitamin $B_6$ intakes with colorectal cancer primarily based on studies in Caucasians, and genetic polymorphisms pertaining to the folate metabolism have been a matter of interest. Less investigated are the roles of methionine synthase (MTR) and thymidylate synthetase (TS) polymorphisms in colorectal carcinogenesis. In a study of 816 cases and 815 community controls in Japan, we investigated associations of dietary intakes of folate, methionine, vitamin $B_2$, vitamin $B_6$, and vitamin $B_{12}$ with colorectal cancer risk. The associations with MTR 2756A>G, MTRR 66A>G, and TSER repeat polymorphism were examined in 685 cases and 778 controls. Methionine and vitamin $B_{12}$ intakes were inversely associated with colorectal cancer risk, but the associations were totally confounded by dietary calcium and n-3 fatty acids. The other nutrients showed no association with the risk even without adjustment for calcium and n-3 fatty acids. The TSER 2R allele was dose-dependently associated with an increased risk. The MTR and MTRR polymorphisms were unrelated to colorectal cancer risk. There was no measurable gene-gene or gene-nutrient interaction, but increased risk associated with the TSER 2R allele seemed to be confined to individuals with high folate status. This study does not support protective associations for folate and vitamin $B_6$. The TSER 2R allele may confer an increased risk of colorectal cancer. The role of the TSER polymorphism in colorectal carcinogenesis may differ by ethnicity.