• Title/Summary/Keyword: Statistical Methods

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Mediation analysis of dietary habits, nutrient intakes, daily life in the relationship between working hours of Korean shift workers and metabolic syndrome : the sixth (2013 ~ 2015) Korea National Health and Nutrition Examination Survey (교대근무자의 근무시간과 대사증후군의 관계에서 식습관, 영양섭취상태, 일상생활의 매개효과 분석 : 6기 국민건강영양조사 (2013 ~ 2015) 데이터 이용)

  • Kim, Yoona;Kim, Hyeon Hee;Lim, Dong Hoon
    • Journal of Nutrition and Health
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    • v.51 no.6
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    • pp.567-579
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    • 2018
  • Purpose: This study examined the mediation effects of dietary habits, nutrient intake, daily life in the relationship between the working hours of Korean shift workers and metabolic syndrome. Methods: Data were collected from the sixth (2013-2015) Korea National Health and Nutrition Examination Survey (KNHANES). The stochastic regression imputation was used to fill missing data. Statistical analysis was performed in Korean shift workers with metabolic syndrome using the SPSS 24 program for Windows and a structural equation model (SEM) using an analysis of moment structure (AMOS) 21.0 package. Results: The model fitted the data well in terms of the goodness of fit index (GFI) = 0.939, root mean square error of approximation (RMSEA) = 0.025, normed fit index (NFI) = 0.917, Tucker-Lewis index (TLI) = 0.984, comparative fit index (CFI) = 0.987, and adjusted goodness of fit index (AGFI) = 0.915. Specific mediation effect of dietary habits (p = 0.023) was statistically significant in the impact of the working hours of shift workers on nutrient intake, and specific mediation effect of daily life (p = 0.019) was statistically significant in the impact of the working hours of shift workers on metabolic syndrome. On the other hand, the dietary habits, nutrient intake and daily life had no significant multiple mediator effects on the working hours of shift workers with metabolic syndrome. Conclusion: The appropriate model suggests that working hours have direct effect on the daily life, which has the mediation effect on the risk of metabolic syndrome in shift workers.

Psychological Characteristics of Living Liver Transplantation Donors using MMPI-2 Profiles (MMPI-2를 이용한 생체 간 공여자들의 심리적 특성에 대한 연구)

  • Lee, Jin Hyeok;Choi, Tae Young;Yoon, Seoyoung
    • Korean Journal of Psychosomatic Medicine
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    • v.27 no.1
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    • pp.42-49
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    • 2019
  • Objectives : Living donor liver transplantation (LDLT) is a life-saving therapy for patients with terminal liver disease. Many studies have focused on recipients rather than donors. The aim of this study was to assess the emotional status and personality characteristics of LDLT donors. Methods : We evaluated 218 subjects (126 male, 92 female) who visited Daegu Catholic University Medical Center from August 2012 to July 2018. A retrospective review of their preoperative psychological evaluation was done. We investigated epidemiological data and the Minnesota Multiphasic Personality Inventory-2 questionnaire. Subanalysis was done depending on whether subjects actually underwent surgery, relationship with the recipient, and their gender. Results : Mean age of subjects was $32.19{\pm}10.91years$. 187 subjects received LDLT surgery (actual donors) while 31 subjects didn't (potential donors). Donor-recipient relationship included husband-wife, parent-children, brother-sister etc. Subjects had statistical significance on validity scale L, F, K and all clinical scales compared to the control group. Potential donors had significant difference in F(b), F(p), K, S, Pa, AGGR, PSYC, DISC and NEGE scales compared to actual donors. F, D and NEGE scales were found to be predictive for actual donation. Subanalysis on donor-recipient relationship and gender also showed significant difference in certain scales. Conclusions : Under-reporting of psychological problems should be considered when evaluating living-liver donors. Information about the donor's overall psychosocial background, mental status and donation process should also be acquired.

Mobile application-based dietary sugar intake reduction intervention study according to the stages of behavior change in female college students (모바일 어플리케이션 기반 당류 저감화 중재 프로그램의 행동변화단계에 따른 효과 분석 : 일부 여대생 대상 연구)

  • Choi, Yunjung;Kim, Hyun-Sook
    • Journal of Nutrition and Health
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    • v.52 no.5
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    • pp.488-500
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    • 2019
  • Purpose: This study examined the effects of a mobile app-based program to reduce the dietary sugar intake according to the stages of the behavioral change in dietary sugar reduction in female college students. Methods: The program used in this study can monitor the dietary sugar intake after recording the dietary intake and provide education message for the reduction of dietary sugar intake. In an eight-week pre-post intervention study, 68 female college students were instructed to record all the food they consumed daily and received weekly education information. At pre-post intervention, the subjects were asked to answer the questionnaire about sugar-related nutrition knowledge, sugar-intake behavior, and sugar-intake frequency. For statistical analysis, ANOVA and a paired t-test were used for comparative analysis according Precontemplation (PC), Contemplation Preparation (C P), and A M (Action Maintenance) stage. Results: Significant differences were observed in the frequency of snacking, experience of nutrition education, and preference for sweetness according to the stages of behavior change in dietary sugar reduction. After finishing an intervention, the sugar-related nutrition knowledge score was increased significantly in the stages of Precontemplation (PC) and Contemplation Preparation (C P). The score of the sugar intake behavior increased significantly in all stages. The intake frequency of chocolate, muffins or cakes, and drinking yogurt decreased significantly in the PC stage and the intake frequency of biscuits, carbonated beverages, and fruit juice decreased significantly in the C P stage. Subjects in the PC and C P stages had an undesirable propensity in nutrition knowledge, sugar-intake behavior, and sugar-intake frequency compared to the A M stage, but this intervention improved significantly their nutrition knowledge, sugar-intake behavior, and sugar-intake frequency. Conclusion: This program can be an effective educational tool in the stages of PC and C P, and is expected to further increase the usability and sustainability of mobile application if supplemented appropriately to a health platform program.

A Study on the Quality Improvement of Brain Perfusion SPECT Image (뇌혈류 단일광자방출단층촬영 영상 품질 향상에 대한 연구)

  • Kil, Sang-Hyeong;Lim, Yung-Hyun;Park, Gwang-Yeol;Cho, Seong-Mook
    • The Korean Journal of Nuclear Medicine Technology
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    • v.23 no.2
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    • pp.13-19
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    • 2019
  • Purpose Tc-99m HMPAO is widely used radiopharmaceutical for brain perfusion SPECT. Tc-99m HMPAO is chemically unstable and is liable to show deterioration of labeling efficiency due to high incidence of secondary Tc-99m HMPAO complex, free pertechnetate and reduced-hydrolyzed Tc-99m. In this study, we investigated whether sialogogues administration could reduce the impurities of Tc-99m HMPAO. Materials and Methods In thirty subjects(20 male and 10 female, age range 19~89 years, mean age $60.7{\pm}14.5years$), brain perfusion SPECT were performed at basal and citric acid stimulation states consecutively after injection of 555 MBq of Tc-99m HMPAO. In the salivary glands, the uptake coefficient was calculated using Siemens processing program. Statistical comparison between before and after the citric acid stimulation performed paired t-test. P value less than 0.05 was regarded as statistically significant. Results Salivary glands uptake was $12900{\pm}3101$ counts in basal and $10677{\pm}2742$ counts in citric acid stimulation states. Unnecessary impurities in the body is much decreased after citric acid administration(t=10.78, P<0.05). The image quality was much improved after administration of citric acid and the regional cerebral perfusion was clearly from demarcated the background. Conclusion The impurity is distributed throughout the body particularly in the salivary glands and nasal mucosa when Tc-99m HMPAO brain perfusion SPECT is performed. If this impurities is not removed, the quality of the image may deteriorate, resulting in errors in visual evaluation. The use of sialogogues could be helpful for decreasing unnecessary impurities in the body.

Effect of abutment superimposition process of dental model scanner on final virtual model (치과용 모형 스캐너의 지대치 중첩 과정이 최종 가상 모형에 미치는 영향)

  • Yu, Beom-Young;Son, Keunbada;Lee, Kyu-Bok
    • The Journal of Korean Academy of Prosthodontics
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    • v.57 no.3
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    • pp.203-210
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    • 2019
  • Purpose: The purpose of this study was to verify the effect of the abutment superimposition process on the final virtual model in the scanning process of single and 3-units bridge model using a dental model scanner. Materials and methods: A gypsum model for single and 3-unit bridges was manufactured for evaluating. And working casts with removable dies were made using Pindex system. A dental model scanner (3Shape E1 scanner) was used to obtain CAD reference model (CRM) and CAD test model (CTM). The CRM was scanned without removing after dividing the abutments in the working cast. Then, CTM was scanned with separated from the divided abutments and superimposed on the CRM (n=20). Finally, three-dimensional analysis software (Geomagic control X) was used to analyze the root mean square (RMS) and Mann-Whitney U test was used for statistical analysis (${\alpha}=.05$). Results: The RMS mean abutment for single full crown preparation was $10.93{\mu}m$ and the RMS average abutment for 3 unit bridge preparation was $6.9{\mu}m$. The RMS mean of the two groups showed statistically significant differences (P<.001). In addition, errors of positive and negative of two groups averaged $9.83{\mu}m$, $-6.79{\mu}m$ and 3-units bridge abutment $6.22{\mu}m$, $-3.3{\mu}m$, respectively. The mean values of the errors of positive and negative of two groups were all statistically significantly lower in 3-unit bridge abutments (P<.001). Conclusion: Although the number of abutments increased during the scan process of the working cast with removable dies, the error due to the superimposition of abutments did not increase. There was also a significantly higher error in single abutments, but within the range of clinically acceptable scan accuracy.

Predicting Forest Gross Primary Production Using Machine Learning Algorithms (머신러닝 기법의 산림 총일차생산성 예측 모델 비교)

  • Lee, Bora;Jang, Keunchang;Kim, Eunsook;Kang, Minseok;Chun, Jung-Hwa;Lim, Jong-Hwan
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.21 no.1
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    • pp.29-41
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    • 2019
  • Terrestrial Gross Primary Production (GPP) is the largest global carbon flux, and forest ecosystems are important because of the ability to store much more significant amounts of carbon than other terrestrial ecosystems. There have been several attempts to estimate GPP using mechanism-based models. However, mechanism-based models including biological, chemical, and physical processes are limited due to a lack of flexibility in predicting non-stationary ecological processes, which are caused by a local and global change. Instead mechanism-free methods are strongly recommended to estimate nonlinear dynamics that occur in nature like GPP. Therefore, we used the mechanism-free machine learning techniques to estimate the daily GPP. In this study, support vector machine (SVM), random forest (RF) and artificial neural network (ANN) were used and compared with the traditional multiple linear regression model (LM). MODIS products and meteorological parameters from eddy covariance data were employed to train the machine learning and LM models from 2006 to 2013. GPP prediction models were compared with daily GPP from eddy covariance measurement in a deciduous forest in South Korea in 2014 and 2015. Statistical analysis including correlation coefficient (R), root mean square error (RMSE) and mean squared error (MSE) were used to evaluate the performance of models. In general, the models from machine-learning algorithms (R = 0.85 - 0.93, MSE = 1.00 - 2.05, p < 0.001) showed better performance than linear regression model (R = 0.82 - 0.92, MSE = 1.24 - 2.45, p < 0.001). These results provide insight into high predictability and the possibility of expansion through the use of the mechanism-free machine-learning models and remote sensing for predicting non-stationary ecological processes such as seasonal GPP.

Comparison and Review of GBEF% on the Anterior and Right Lateral Images of Nuclear Hepatobiliary Scan (핵의학 간담도 스캔 시, 전면상과 우측 측면상에서의 담낭박출률에 대한 비교 및 고찰)

  • Lee, Eun-Byeol;Kim, Jae-Il;Do, Yong-Ho;Llm, Jung-Jin;Cho, Sung-Wook;Noh, Gyeong-Woon
    • The Korean Journal of Nuclear Medicine Technology
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    • v.22 no.2
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    • pp.92-96
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    • 2018
  • Purpose In case of nuclear medical hepatobiliary scan, To quantitatively evaluate contractility of a gallbladder, gallbladder ejection fraction (GBEF%) is calculated from anterior images using fatty meal. However, when a gallbladder and other organs overlap on an anterior image, the gallbladder ejection fraction is not accurately evaluated. In order to reduce this error, the objective of our study was to figure out whether there is a significant difference in GBEF% calculated from the anterior and right lateral images. Materials and Methods After intravenous injection of 99mTc-Mebrofenin 370 MBq to randomly 50 patients who visited our hospital, we started to examine nuclear hepatobiliary scan. Using skylight(Philips, United States), we acquired anterior and right lateral image at 10 minutes, 20 minutes, 30 minutes, 60 minutes, 90minutes after injection. Using images at 60 and 90 minutes, gallbladder ejection fraction (GBEF%) was calculated from the anterior and right lateral images using JETstream workspace. For drawing more accurate ROI, CT images were referenced and 4 radiologists calculated the GBEF% in the same image and calculated the average value. We assessed whether there was a significant difference in GBEF% calculated from the anterior and right lateral images using SPSS program(Statistical Package for the Social Science, SPSS Ver.18 Inc. USA). Results About randomly 50 patients, the average value of the GBEF% calculated from the anterior image was 63.212 and the average value of the GBEF% calculated from the right lateral image was 62.666. GBEF% decreased 0.433% on the right lateral image compared with anterior image. Result of paired sample t-test, p value is over 0.05. So, there was no significant difference in GBEF% calculated from the anterior and right lateral images. Conclusion In the case that a gallbladder and other organs are not separated on an anteior image, Right lateral image would be better to acquire more accurate GBEF% than using anterior image.

Analysis of esthetic factors and evaluation of esthetic perception for maxillary anteriors of dental students (치과대학생의 상악 전치부의 심미적 요소 분석 및 인식도 평가)

  • Kim, Seon-Kyung;Kim, Ok-Su
    • The Journal of Korean Academy of Prosthodontics
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    • v.57 no.2
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    • pp.118-126
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    • 2019
  • Purpose: This research is to investigate factors that affect dental aesthetics and analyze whether individual perception affects and difference of genders affects the esthetic factors. Materials and methods: Seventy dental students of Chonnam University aged from 25 to 35 years old without periodontal problems were included. Maxillary dental cast for participants were made, and standardized photo was taken with a digital camera. Maximum visual width and the position of gingival zenith of maxillary anterior teeth and maximum height of the maxillary central incisors were measured by a measurement program and the shape of central incisor was categorized. Questionnaire was conducted to evaluate esthetic perception. SPSS program was used to perform statistical analysis. Results: The average visual width ratio of right maxillary anteriors was 1.38:1:0.78 and 1.41:1:0.81 for the left which differ from the golden ratio. The width to height ratio for right and left central incisor was 0.84 and 0.83 respectively. The gingival zenith position was determined to be: mostly, central incisors and canines were located in the distal side, lateral incisors were located in the center. The visual width ratio of right maxillary anterior teeth, ratio of width to height of central incisor, gingival zenith position, crown morphology and amounts of gingival exposure upon smiling were not significantly different between genders, and facial patterns and these dental esthetic factors were not related to aesthetic perception. Conclusion: Even though participants had the visual width ratio of maxillary anteriors or ideal width to ideal height of central incisors that did not agree with the golden ratio, they had high satisfaction for dental esthetics. Esthetic perception depends more on subjective judgements of participants than objective indices.

Comparison of the accuracy of intraoral scanner by three-dimensional analysis in single and 3-unit bridge abutment model: In vitro study (단일 수복물과 3본 고정성 수복물 지대치 모델에서 삼차원 분석을 통한 구강 스캐너의 정확도 비교)

  • Huang, Mei-Yang;Son, Keunbada;Lee, Wan-Sun;Lee, Kyu-Bok
    • The Journal of Korean Academy of Prosthodontics
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    • v.57 no.2
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    • pp.102-109
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    • 2019
  • Purpose: The purpose of this study was to evaluate the accuracy of three types of intraoral scanners and the accuracy of the single abutment and bridge abutment model. Materials and methods: In this study, a single abutment, and a bridge abutment with missing first molar was fabricated and set as the reference model. The reference model was scanned with an industrial three-dimensional scanner and set as reference scan data. The reference model was scanned five times using the three intraoral scanners (CS3600, CS3500, and EZIS PO). This was set as the evaluation scan data. In the three-dimensional analysis (Geomagic control X), the divided abutment region was selected and analyzed to verify the scan accuracy of the abutment. Statistical analysis was performed using SPSS software (${\alpha}=.05$). The accuracy of intraoral scanners was compared using the Kruskal-Wallis test and post-test was performed using the Pairwise test. The accuracy difference between the single abutment model and the bridge abutment model was analyzed by the Mann-Whitney U test. Results: The accuracy according to the intraoral scanner was significantly different (P < .05). The trueness of the single abutment model and the bridge abutment model showed a statistically significant difference and showed better trueness in the single abutment (P < .05). There was no significant difference in the precision (P = .616). Conclusion: As a result of comparing the accuracy of single and bridge abutments, the error of abutment scan increased with increasing scan area, and the accuracy of bridge abutment model was clinically acceptable in three types of intraoral scanners.

Development of nutrition quotient for elementary school children to evaluate dietary quality and eating behaviors (학령기 아동 대상 영양지수 개발과 타당도 검증)

  • Lee, Jung-Sug;Hwang, Ji-Yun;Kwon, Sehyug;Chung, Hae-Rang;Kwak, Tong-Kyung;Kang, Myung-Hee;Choi, Young-Sun;Kim, Hye-Young
    • Journal of Nutrition and Health
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    • v.53 no.6
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    • pp.629-647
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    • 2020
  • Purpose: This study was undertaken to develop a nutrition quotient for elementary school children (NQ-C) for evaluating the overall dietary quality and eating behaviors. Methods: The NQ-C was developed by implementing 3 stages: item generation, item reduction, and validation. Candidate food behavior checklist (FBC) items of the NQ-C were derived from systematic literature reviews, expert in-depth interviews, statistical analyses of the fifth Korean National Health and Nutrition Examination Survey data, and national nutrition policies and recommendations. For the pilot survey, 260 elementary school students (128 second graders and 132 fifth graders) completed self-administered questionnaires as well as 24-hour dietary intakes, with the help of their parents and survey team staff, if required. Based on the pilot survey results, expert reviews, and priorities of national nutrition policy and recommendations, checklist items were reduced from 41 to 24. A total of 20 items for NQ-C were finally selected from results generated from 1,144 nationwide samples surveyed. Construct validity of the NQ-C was assessed using the confirmatory factor analysis, LInear Structural RELations. Results: Analyses of the exploratory factors of NQ-C identified that 5 dimensions of diet (balance, diversity, moderation, practice and environment) accounted for 46.2% of the total variance. Standardized path coefficients were used as weights of the items. The NQ-C and 5-factor scores of the subjects were calculated using the obtained weights of the FBC items. Conclusion: Our data indicates that NQ-C is a useful and suitable instrument for assessing nutrition adequacy, dietary quality, and eating behaviors of Korean elementary school children.