• 충청수학회지
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• 제30권4호
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• pp.397-409
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• 2017

In this paper, we investigated the extinction, positivity, and decay estimates of the solutions to the initial-boundary value problem of the semilinear parabolic equation with nonlinear gradient source and interior absorption terms by using the integral norm estimate method. We found that the decay estimates depend on the choices of initial data, coefficients and domain, and the first eigenvalue of the Laplacean operator with homogeneous Dirichlet boundary condition plays an important role in the proofs of main results.

• Tuberculosis and Respiratory Diseases
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• 제81권3호
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• pp.233-240
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• 2018

Background: Non-conversion of sputum smear and culture prolongs the infectivity of the patient and has been associated with unfavorable outcomes. We aimed to evaluate factors associated with persistent sputum positivity at the end of two months of treatment of new case pulmonary tuberculosis (TB). Methods: Data of 87 human immunodeficiency virus-negative patients with culture-positive drug-susceptible pulmonary TB admitted to local university hospital between September 2015 and September 2016 were reviewed. Factors associated with sputum smear and/or culture positivity at the end of the second month of treatment were analyzed. Results: Twenty-two patients (25.3%) remained smear and/or culture-positive. Male sex, lower body mass index (BMI), unemployment, alcohol abuse, higher number of lobes involved and cavities on chest X-rays, shorter time to detection (TTD) on liquid cultures, higher respiratory sample smear grading and colony count in solid cultures, higher C-reactive protein, erythrocyte sedimentation rate, leukocytosis, thrombocytosis, and anemia were all significantly associated with persistent sputum positivity. However, in the logistic regression analysis only male sex, lower BMI, alcohol abuse, higher radiological involvement, cavitation, higher smear grading, higher colony count in solid cultures and shorter TTD were determined as independent factors associated with persistent sputum positivity at the end of 2 months of treatment. Conclusion: In conclusion, higher sputum smear and culture grading at diagnosis, shorter TTD, higher number of lobes involved, cavitation, male sex, alcohol abuse, and lower BMI were independently associated with persistent sputum positivity. These factors should be sought when distinguishing which patients will remain infectious longer and possibly have worse outcomes.

• Korean Journal of Mathematics
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• 제9권1호
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• pp.53-60
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• 2001

We study the properties of positivity of matrices and construct useful positive matrices. As an application, we consider a directed graph with matrices such that all the associated matrices related to the positive linear functional are positive.

• Communications for Statistical Applications and Methods
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• 제23권1호
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• pp.1-20
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• 2016

Causal inference methodologies have been developed for the past decade to estimate the unconfounded effect of an exposure under several key assumptions. These assumptions include, but are not limited to, the stable unit treatment value assumption, the strong ignorability of treatment assignment assumption, and the assumption that propensity scores be bounded away from zero and one (the positivity assumption). Of these assumptions, the first two have received much attention in the literature. Yet the positivity assumption has been recently discussed in only a few papers. Propensity scores of zero or one are indicative of deterministic exposure so that causal effects cannot be defined for these subjects. Therefore, these subjects need to be removed because no comparable comparison groups can be found for such subjects. In this paper, using currently available causal inference methods, we evaluate the effect of arbitrary cutoffs in the distribution of propensity scores and the impact of those decisions on bias and efficiency. We propose a tree-based method that performs well in terms of bias reduction when the definition of positivity is based on a single confounder. This tree-based method can be easily implemented using the statistical software program, R. R code for the studies is available online.

• 동아시아식생활학회지
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• 제23권6호
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• pp.862-870
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• 2013

This study examines the effect of communication type of food service employees on the self-efficiency and organizational commitment. To accomplish the purpose of the study, a survey was conducted to employees of food service companies located in Seoul, from August 5, 2013 to August 25, 2013 as a method of empirical study. The results of this study was analyzed using the SPSS WIN 12.0 and statistical reliability analysis, factor analysis, frequency analysis, correlation analysis and multiple regression analysis were conducted for hypothesis verification. The analysis results of this study are as follows. First, the R-square of regression result for 'communication type will have a positive effect on self-efficiency' was .220. Also, it was found that factors of consideration (Beta=.286, t=5.622), instruction (Beta=.303, t=5.970) and business (Beta=.214, t=4.217) had positive effects on self-efficiency. Values for factors of consideration and instruction were higher than business. Second, the R-square of regression result for 'communication type will have a positive effect on organizational commitment' was .429. Also, it was found that factors of consideration (Beta=.453, t=10.428), instruction (Beta=.380, t=8.749) and business (Beta=.282, t=6.477) had positive effects on organizational commitment. Values for factors of instruction and business were high but value of consideration factor turned out the highest. Third, the R-square of regression result for 'self-efficiency will have a positive effect on organizational commitment' was .334. Also, it was found that out of the factors of positivity (Beta=.369, t=8.423), confidence (Beta=.415, t=8.833) and negativity (Beta=-.072, t=-1.536), positivity and confidence had positive effects on organization commitment, and only positivity and confidence showed high values in organization commitment. Upon analyzing the effect of factors of self-efficiency (positivity, confidence, negativity) on organizational commitment, it was found that positivity and confidence showed high relevance but the negativity factor did not have any correlation.

• Asian Pacific Journal of Cancer Prevention
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• 제14권3호
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• pp.1797-1802
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• 2013

Background: The aim of this study was to assess clinical factors associated with Helicobacter pylori positivity and to evaluate the incidence of gastric carcinoma in first-degree family members of infected patients. A total of 580 patients (mean age:$38{\pm}17$) with gastrointestinal complaints underwent C-14 urea breath test (UBT). Patients were grouped as: Group-1, untreated patients (n:384); and Group-2, patients who previously treated with eradication triple therapy (n:196). C-14 UBT was performed 1-2 months after the completion of eradication therapy. Associations of H pylori positivity with age, gender, ABO and Rhesus groups, smoking, dietary habits, and history of gastric cancer in first-degree family members were evaluated. The frequency of H pylori positivity was significantly higher in group-1 (58%) compared to group-2 (20%), p=0.001. There were no correlations between H pylori positivity and age, gender, ABO groups, Rhesus subgroups, smoking and dietary habits in both patient groups. The frequency of gastric cancer in family members was significantly higher in patients with H pylori infection among group-1, compared to infected patients among group-2 (56% vs. 28.6% respectively, p=0.03). We observed a significant association between H pylori positivity and the presence of gastric cancer in first-degree relatives of group-1 patients. Our results provide some confirmation of the presence of a link between gastric cancer development and H pylori. C-14 UBT is a sensitive, reliable and a widely recommended test for the detection of H pylori infection and recurrence. We suggest that detection and eradication of H pylori may contribute to a reduced risk of gastric cancer in the family members of infected patients.

• 대한한의학회지
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• 제22권4호
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• pp.29-36
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• 2001

Objectives: This study attempted to investigate the allergic histories and the distribution of offending allergens in the general public and further to help their diagnosis and treatment with Oriental Medicine. Methods: Allergic skin tests (AST) were performed and allergic histories were taken of 359 members of the general public who visited the International Exhibition on Oriental Medicine from Sept. 1 to Sept. 5, 2000. The allergen reagents for AST were three (House dust, D. farinae, Dog hair) and the control reagent was histamine solution. Results: 1.50.1 % of the subjects (n=359) were positive to AST. The ratio between males' positivity and females' was 1.06：1. 2. The younger the subjects were, the higher the positivity was. 3. The positive subjects' (n=180) positivity to three allergens was as follows: D. farinae 98.9%, House dust 30.0%, Dog hair 1.7%. 4. The younger the positive subjects were, the higher the positivity to House dust was. In contrast, the positivity to D. farinae was high in all age groups. 5.71.1 % of the positive subjects reacted positively to monotype allergen and 28.9% reacted positively to multiple allergens (2.46：1). The most common monotype allergen was D. farinae (98.4%) and the most common combination of multiple allergens was House dust and D. farinae (94.2%). 6.52.8% of the positive subjects (n=180) and 51.4% of the negative subjects (n=179) represented the history of allergic diseases. There was no relationship between allergic skin test and allergic diseases. Conclusion: To help in diagnosis and treatment with oriental medicine, research to analyze the relationship between allergic skin test and allergic diseases should be continued on the basis of Oriental medical theories.

• 한국콘텐츠학회논문지
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• 제16권12호
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• pp.281-290
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• 2016

본 연구는 직업군인의 긍정성과 가족의사소통이 조직몰입에 미치는 영향을 확인하고 이들의 관계에서 자기효능감의 매개효과를 알아보는 것이 목적이다. 이를 위해 2015년 국방부의 승인을 거친 직업군인들에 대한 연구에 대해 육 해 공 해병대 부대의 협조를 구하여 장기복무 직업군인 241명에게 설문조사를 거쳤으며 SPSS 21.0과 AMOS 21.0을 사용하여 분석하였다. 연구결과는 첫째, 장기복무 직업군인의 조직몰입은 긍정성, 가족의사소통 그리고 자기효능감과 모두 정적 상관관계를 가지는 것으로 나타났다. 둘째, 조직몰입에 영향을 미치는 변인을 모두 고려하여 분석한 결과, 측정모형과 구조모형의 적합도는 양호한 것으로 나타났으며 직업군인의 조직몰입에 대해 긍정성과 가족의사소통은 긍정적인 영향을 미치며 이들의 관계에서 자기효능감은 매개효과를 가지는 것으로 나타났다. 이와 같은 연구결과를 토대로 장기복무 직업군인의 조직몰입을 위한 효과적인 함의를 제시하고자 한다.

• Tuberculosis and Respiratory Diseases
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• 제85권1호
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• pp.80-88
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• 2022

Background: Although it is known that inhaled corticosteroid (ICS) use may increase the risk of respiratory infection, its influence on the risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection remains unknown. Thus, the aim of this study was to investigate the association between ICS use and the positivity of SARS-CoV-2 infection among patients with chronic respiratory diseases. Methods: Nationwide data of 44,968 individuals with chronic respiratory diseases tested for SARS-CoV-2 until May 15, 2021 were obtained from the Ministry of Health and Welfare and Health Insurance Review and Assessment Service in Korea. The positivity of SARS-CoV-2 infection was retrospectively analysed according to the prescription, type, and dose of ICS taken one year before SARS-CoV-2 test. Results: Among 44,968 individuals tested, 931 (2.1%) were positive for SARS-CoV-2. A total of 7,019 patients (15.6%) were prescribed ICS one year prior to being tested for SARS-CoV-2. Low, medium, and high doses of ICS were prescribed in 7.5%, 1.6%, and 6.5% of total cases, respectively. Among types of ICS, budesonide, fluticasone, beclomethasone, and ciclesonide were prescribed in 3.7%, 8.9%, 2.3%, and 0.6% of total cases, respectively. A multivariate analysis showed no significant increase in infection with ICS use (odds ratio, 0.84; 95% confidence interval, 0.66-1.03). Moreover, there were no associations between the positivity of infection and the dose or type of ICS prescribed. Conclusion: Prior ICS use did not increase the positivity for SARS-CoV-2 infection. Moreover, different doses or types of ICS did not affect this positivity.

• Asian Pacific Journal of Cancer Prevention
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• 제14권7호
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• pp.4353-4358
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• 2013

Introduction: Breast cancer aggressiveness can be correlated with proliferation status of tumor cells, which can be ascertained with tumor grade and Ki67 indexing. However due to lack of reproducibility, the ASCO do not recommend routine use of Ki67 in determining prognosis in newly diagnosed breast cancers. We therefore aimed to determine associations of the Ki67 index with other prognostic markers like tumor size, grade, lymph node metastasis, ER, PR and HER2neu status. Methods: A total of 194 cases of newly diagnosed breast cancer were included in the study. Immunohistochemical staining for ER, PR, HER2neu and Ki67 was performed by the DAKO envision method. Associations of the Ki67 index with other prognostic factors were evaluated both as continuous and categorical variables. Results: Mean age of the patients was 51.7 years (24-90). Mean Ki67 index was 26.9% (1-90). ER, PR, HER2neu positivity was noted in 90/194 cases (46.4%), 74/194 cases (38.1%) and 110/194 cases (56.70%) respectively. Significant association was found between Ki67 and tumor grade, PR, HER2neu positivity and lymph node status, but no link was apparent with ER positivity and tumor size. There wasan inverse relation between Ki67 index and PR positivity, whereas a direct correlation was seen with HER2neu positivity. However, high Ki67 (>30%) was associated with decreased HER2neu positivity as compared to intermediate Ki67 (16-30%). The same trend was established with lymph node metastasis. Conclusion: Our study indicates that with high grade tumors, clinical utility of ki67 is greater in combination with other prognostic markers because we found that tumors with Ki67 higher than 30% have better prognostic profile compared to tumors with intermediate Ki67 level, as reflected by slightly lower frequency of lymph node metastasis and HER2neu expression. Therefore we suggest that Ki67 index should be categorized into high, intermediate and low groups when considering adjuvant chemotherapy and prognostic stratification.