• Genomics & Informatics
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• v.20 no.1
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• pp.9.1-9.6
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• 2022

Mendelian randomization (MR) uses genetic variation as a natural experiment to investigate the causal effects of modifiable risk factors (exposures) on outcomes. Two-sample Mendelian randomization (2SMR) is widely used to measure causal effects between exposures and outcomes via genome-wide association studies. 2SMR can increase statistical power by utilizing summary statistics from large consortia such as the UK Biobank. However, the first-order term approximation of standard error is commonly used when applying 2SMR. This approximation can underestimate the variance of causal effects in MR, which can lead to an increased false-positive rate. An alternative is to use the second-order approximation of the standard error, which can considerably correct for the deviation of the first-order approximation. In this study, we simulated MR to show the degree to which the first-order approximation underestimates the variance. We show that depending on the specific situation, the first-order approximation can underestimate the variance almost by half when compared to the true variance, whereas the second-order approximation is robust and accurate.

• Nutrition Research and Practice
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• v.13 no.6
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• pp.498-508
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• 2019

BACKGROUND/OBJECTIVES: Lower circulating 25-hydroxyvitamin D [25(OH)D] levels are associated with a higher risk of hypertension (HTN); however, it remains unclear whether the relationship is causal. We aimed to evaluate the causal effects of circulating 25(OH)D levels on the prevalence of HTN in the Korean population using the Mendelian randomization (MR) approach. SUBJECTS/METHODS: Epidemiological data, serum 25(OH)D data, and genomic DNA biospecimens were obtained from 2,591 participants, a subset of the study population in the Korea National Health and Nutrition Survey 2011-2012. Five 25(OH)D-related single nucleotide polymorphisms (SNPs; DHCR7 rs12785878, CYP2R1 rs10741657, CYP2R1 rs12794714, CYP24A1 rs6013897, and GC rs2282679), identified a priori from genome-wide association studies, were used as instrument variables (IVs) for serum 25(OH)D levels. In the MR analysis, we performed IV analyses using the two-stage least squares method. RESULTS: In the observational analysis, circulating 25(OH)D levels were found to be inversely associated with the HTN prevalence in ordinary least squares models (odds ratio: 0.97, 95% confidence interval: 0.96, 0.99) after adjusting for the potential confounders. There were differences in the circulating 25(OH)D levels across genotypes of individual SNPs. In the MR analysis, using individual SNPs as IVs, 25(OH)D levels were not associated with the HTN prevalence. CONCLUSIONS: We found no association between genetically determined circulating 25(OH)D levels and HTN in Korean adults. Our results are listed owing to the relatively small sample size and possible weak instrument bias; therefore, further studies are needed to confirm these results.

• Proceedings of the Korea Society of Design Studies Conference
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• 2004.05a
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• pp.204-205
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• 2004

• Proceedings of the Korea Society of Design Studies Conference
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• 2005.10a
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• pp.256-257
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• 2005

• YAKHAK HOEJI
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• v.28 no.3
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• pp.139-147
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• 1984

L-PHA, a lectin having lymphoagglutinating activity but devoid of erythroagglutinability which is contained in Korean white kidney bean (Phaseolus vulgaris L.), was isolated and purified through several techniques such as ion exchange chromatography, hydroxyapatite column and affinity chromatography. Purified L-PHA was identified as a single band by polyacrylamide disc gel electrophoresis. The molecular weight of the L-PHA was estimated about 125, 000 daltons by polyacrylamide gel electrophoresis and it was turned out having one subunit (probably dimer of the Yachnin's model) of Mr~60, 000. Immunochemical studies also tried and these results reconfirmed the purity of this L-PHA.

• Cross-Cultural Studies
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• v.21
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• pp.139-164
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• 2010

Sung Yung Shin was adopted as a Korean infant to an American family. She is now one of the most important writers in Asian American literary field. This paper analyzes the characteristics of her literature, focusing on Skirt full of Black (poetry)and Cooper's Lesson(children's book). Sun Yung Shin uses collage in Skirt full of Black as an effective rhetorical device because it can express her experience as an adopted other in the multicultural American society. She rewrites the fairy tale of Swan Prince in the viewpoint of silence. For a yellow Asian adopted woman, speaking is suppressed. In the end, the attempt to escape from silence is the writer's resisting activity, and the rewriting of the tale is her questioning in place of the princess. I analyses Cooper's Lesson in the viewpoint of transcultural assimilation. Cooper's lesson is accomplished not by his white father but by a Korean settler, Mr. Lee. Cooper's family is a hybrid composed of white American father, Korean mother, and their half son. So this family has many complicated difficulties, though it's small. Mr. Lee who accepted a new language to establish a new identity teaches Cooper the importance of cultural assimilation, which is not a one-sided integration to dominant culture but an intercultural communion while sustaining each culture's singularity. Cooper learns that he should live in an harmonious and balanced life in a multi-cultural society while keeping his own subjective point of view.

• English & American cultural studies
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• v.9 no.1
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• pp.297-321
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• 2009

The purpose of this study is to re-read the film of Dead Poets Society, specially focused on a feminist view. The film hides the strategy of recovering the traditional Patriarchal Society. At the beginning, the film resists the values of traditional society through John Keating. His unorthodox methods of teaching literature smack against the traditions of Welton Academy. Furthermore, he stresses on "Carpe Diem"—Seize the Day, the romantic values of free thinking, creativity, and individuality. The forces opposing Keating's philosophy are personified by Welton's rigid, old headmaster, Mr. Nolan, and the cruel, stubborn parent, Mr. Perry. Keating's romantic values are failed by their powerful, dominating attitudes. Effected by Keating's philosophy, Neil decides to pursue acting rather than medicine. He conflicts with his strict father. Finally frustrated by his authority, Neil commits suicide. And Keating is accused of inciting the boys to restart the Dead Poets Society, and at last he is fired. Keating and Neil are victimized by the Patriarchal society. Even though the film concentrates male characters at the all boys' school, it reveals the male angle of binary oppositions between men and women, subject and object, activity and passivity, presence and absence. In the film's dramatic conclusion, English class is now being temporarily taught by Nolan, who has the boys read from the very Pritchard essay they had ripped out at the start of the film. It symbolizes the triumph of the traditional logocentric society. However, influenced by Keating's unconventional attitudes, ultimately Welton Academy will be changed as it is embodied in its closing scene.

• Journal of Korean Neurosurgical Society
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• v.46 no.1
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• pp.38-44
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• 2009

Objective : The authors studied the risk factors of silent cerebral microbleeds (MBs) and old hematomas (OHs) and their association with concurrent magnetic resonance (MR) imaging findings in the patients of intracerebral hemorrhages (ICHs). Methods : From April 2002 to June 2007, we retrospectively studied 234 patients of primary hemorrhagic stroke. All patients were evaluated with computed tomography (CT) and 3.0-tesla MR imaging studies within the first week of admission. MBs and OHs were assessed by using $T2^{\ast}$-weighted gradient-echo (GRE) MR imaging. The patients were divided into 2 groups, depending on whether or not they had two GRE lesions of chronic hemorrhages. A correlation between MBs and OHs lesions were also statistically tested. Lacunes and white matter and periventricular hyperintensities (WMHs, PVHs) were checked by T1- and T2-weighted spin-echo and fluid attenuated inversion recovery sequences. Variables on the clinical and laboratory data and MR imaging abnormalities were compared between both groups with or without MBs and OHs. Results : MBs were observed in 186 (79.5%) patients and a total of 46 OHs were detected in 45 (19.2%) patients. MBs (39.6%), OHs (80.4%), and ICHs (69.7%) were most commonly located in the ganglionic/thalamic region. Both MBs and OHs groups were more frequently related to chronic hypertension and advanced WMHs and PVHs. The prevalence and number of MBs were more closely associated with OHs groups than non-OH patients. Conclusion : This study clearly demonstrated the presence of MBs and OHs and their correlation with hypertension and cerebral white matter microangiopathy in the ICHs patients. Topographic correlation between the three lesions (MBs, OHs, and ICHs) was also noted in the deep thalamo-basal location.

• Investigative Magnetic Resonance Imaging
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• v.17 no.2
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• pp.149-153
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• 2013

Detection of cerebrospinal fluid leakage or exact localization of leakage site after spinal surgery is difficult on conventional imaging studies. We report two patients with surgery-related spinal CSF leakage detected on magnetic resonance (MR) myelography. They presented with severe headache after spinal surgeries, lumbar discectomy and excision of spinal meningioma, respectively. The sites of spinal CSF leakage in the patients were detected accurately on MR myelography, and the patients recovered from the postoperative CSF leakage after being treated with an epidural blood patch or reoperation. MR myelography may be effective in demonstrating the exact site of surgery-related spinal CSF leakage.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.2
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• pp.157-164
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• 2016

The paper studies a comparison analysis of semi-active control strategies for a Macpherson strut type suspension system consisting of MR(magneto-rheological) damper. As a first step, in order to formulate governing, a dynamic full model of a Macpherson strut is developed considering the kinematics. The nonlinear equation of motion of the strut is then linearized around the equilibrium point. A new adaptive moving sliding model controller is developed for fast response of the system. A newly proposed adaptive moving sliding mode control strategy is then compared with conventional sliding mode controller and skyhook controller. The comparison is made for two different types of road inputs; bump and random road profiles showing superior vibration control performance in time and frequency domains.