• Title/Summary/Keyword: Mean Normal Stress

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Development and validation of a non-linear k-ε model for flow over a full-scale building

  • Wright, N.G.;Easom, G.J.;Hoxey, R.J.
    • Wind and Structures
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    • v.4 no.3
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    • pp.177-196
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    • 2001
  • At present the most popular turbulence models used for engineering solutions to flow problems are the $k-{\varepsilon}$ and Reynolds stress models. The shortcoming of these models based on the isotropic eddy viscosity concept and Reynolds averaging in flow fields of the type found in the field of Wind Engineering are well documented. In view of these shortcomings this paper presents the implementation of a non-linear model and its evaluation for flow around a building. Tests were undertaken using the classical bluff body shape, a surface mounted cube, with orientations both normal and skewed at $45^{\circ}$ to the incident wind. Full-scale investigations have been undertaken at the Silsoe Research Institute with a 6 m surface mounted cube and a fetch of roughness height equal to 0.01 m. All tests were originally undertaken for a number of turbulence models including the standard, RNG and MMK $k-{\varepsilon}$ models and the differential stress model. The sensitivity of the CFD results to a number of solver parameters was tested. The accuracy of the turbulence model used was deduced by comparison to the full-scale predicted roof and wake recirculation zone lengths. Mean values of the predicted pressure coefficients were used to further validate the turbulence models. Preliminary comparisons have also been made with available published experimental and large eddy simulation data. Initial investigations suggested that a suitable turbulence model should be able to model the anisotropy of turbulent flow such as the Reynolds stress model whilst maintaining the ease of use and computational stability of the two equations models. Therefore development work concentrated on non-linear quadratic and cubic expansions of the Boussinesq eddy viscosity assumption. Comparisons of these with models based on an isotropic assumption are presented along with comparisons with measured data.

Pregnant Women's Antenatal Depression and Influencing Factors (임신여성의 산전 우울 및 영향요인)

  • Koh, Minseon;Ahn, Sukhee;Kim, Jisoon;Park, Seyeon;Oh, Jiwon
    • Women's Health Nursing
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    • v.25 no.1
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    • pp.112-123
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    • 2019
  • Purpose: The objective of this study was to investigate the prevalence of antenatal depression in pregnant women and its influencing factors. Methods: With a cross-sectional survey design, a total of 396 pregnant women were recruited from a local obstetrics and gynecology clinic. Measurements included antenatal depression, perceived stress, predictors of depression during pregnancy, and demographic and obstetric characteristics. Results: Mean antenatal depression score was 8.20 (standard deviation=4.95) out of 30, falling into its normal range. However, the prevalence of antenatal depression was 35.9% when cut-point of 9/10 was used. The prevalence of antenatal depression among women in the first trimester was 31.4%. It was slightly increased to 34.9% in the second trimester but significantly increased to 40.5% in the third trimester. In multiple logistic regression analysis, experiencing prenatal anxiety (odds ratio [OR], 4.16), having no job (OR, 2.90), lower self-esteem (OR, 1.62), and higher perceived stress (OR, 1.32) were significant factors influencing antenatal depression. Conclusion: Negative feeling such as feeling anxious, lower self-esteem, and higher perceived stress during pregnancy are key factors affecting antenatal depression. Thus, antenatal nursing intervention focusing on pregnant women's feeling upon their job status is necessary to improve their antenatal psychological well-being.

Factors associated with the weight change trend in the first year of the COVID-19 pandemic: the case of Turkey

  • Onal, Hulya Yilmaz;Bayram, Banu;Yuksel, Aysun
    • Nutrition Research and Practice
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    • v.15 no.sup1
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    • pp.53-69
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    • 2021
  • BACKGROUND/OBJECTIVES: To determine the weight change trend among the adult Turkish population after 1 yr of the coronavirus disease 2019 (COVID-19) pandemic and factors associated with weight change. MATERIALS/METHODS: This cross-sectional study was conducted between 26 February and 6 March 2021 using an online questionnaire that included questions for sociodemographic variables, eating habits, stress level, and the Three-Factor Eating Questionnaire-R18. Those who weighed themselves 1-2 weeks before the pandemic was declared in Turkey and remembered their weight were invited to participate in the study. Trends in weight and body mass index (BMI) change were calculated. The variables associated with a 1% change in BMI were assessed using hierarchical regression analysis. RESULTS: The study was conducted with 1,630 adults (70.25% female) with a mean age of 32.09 (11.62) yrs. The trend of weight change was found to increase by an average of 1.15 ± 6.10 kg (female +0.72 ± 5.51, male +2.16 ± 7.22 kg) for the first year of the COVID-19 pandemic. The rate of participants with a normal BMI (18.50-24.99 kg/m2) decreased to 51.91% from 55.75%. Consuming an "Increased amount of food compared to before the pandemic" was found to be the independent variable that had the strongest association with a 1% increase in BMI (β = 0.23 P < 0.001). The average change in the BMI was higher in older individuals than in those who were younger. A high stress level was associated with a decrease in BMI (β = -0.04 P = 0.048). CONCLUSIONS: In this study, the factors associated with weight change after 1 yr of the pandemic in the Turkish population was reported for the first time. A high stress level and increased weight gain trend still occur in Turkey after 1 yr of the pandemic.

A study on the Compliance and Educational Demand of Renal Transplantation Patient (신장이식 환자의 치료지시 이행정도와 교육 요구도에 관한 연구)

  • Ryu, Jeong-Ha;Kim, Myung-Hee;Kang, In-Soon
    • The Korean Journal of Rehabilitation Nursing
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    • v.6 no.2
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    • pp.226-238
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    • 2003
  • This study was started for the purpose of providing the basic data for continous managment of kidney transplantation patients after discharge. This study was conducted on 180 patients who received renal transplants at three hospital( B, M, P) pusan, korea. The data collection was done for june 1, to August 31, 2002. General characteristics, renal transplantaton characteristics, physical characteristics, the level of compliance and the degree of educational demand were done by the number and percentage, the mean, standard deviation. The level of compliance and educational demand followed by the characteristics of general and kidney transplantation were analyzed by t-test and ANOVA. The result were as fallows; 1. Man was higher than woman such as 60.0%, Mean age was 42.5 years old, Average total duration of after operation was 5.5 years. 2. Cases of systolic blood pressure over 140mmHg were 10.0%, cases of diastolic blood pressure over 90mmHg were 22.8% and obesity factor in BMI was 15.6%. The person who daily water intake amount is 5000cc was 0.6%, the case that daily urine output is below 1000cc was 8.9%, and the case that urine output is zero was 0.6%. 3. The mean score of compliance was 77.47 point, The score in medication part was highest such as 4.67 point, that in stress situation was lowest such as 3.50 point. 4. The average score of educational demand was 154.02 point, and physical state part was 4.36 points highest, activation part was 3.48 points lowest. As a role of nurse Confirmation of compliance is very important encourage to make good through regular hospital visitation, point out the noncompliance part and then increase compliance of renal transplantation patient As well there will be maintain the normal kidney function to satisfy educational demand through continous education.

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Magnetic Resonance Imaging Analysis of Biological Ligament Healing after Suture-Tape Augmentation for Chronic Lateral Ankle Instability (봉합테이프를 이용한 발목 외측인대 보강술이 생물학적 인대 재생에 미치는 영향)

  • Cho, Byung-Ki;An, Min-Yong;Kim, Yoon-Ho;Ahn, Byung-Hyun
    • Journal of Korean Foot and Ankle Society
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    • v.25 no.3
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    • pp.117-125
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    • 2021
  • Purpose: The aim of this study was to evaluate biological ligament healing quantitatively after suture-tape augmentation for chronic lateral ankle instability. Materials and Methods: Thirty-two patients underwent magnetic resonance imaging (MRI) at a minimum of 2 years after lateral ligament augmentation using suture-tape. Signal/noise ratios (SNRs) and widths of anterior talofibular ligaments (ATFLs) were measured on preoperative and postoperative MRI by three researchers. ATFL biological healing degrees were analyzed using changes in SNRs and widths of ATFLs and by comparing these metrics with those of normal contralateral ankles. Clinical evaluations were performed using foot and ankle outcome scores (FAOSs), Foot and Ankle Ability Measure (FAAM) scores, and ankle stress radiographs. Results: Mean FAOS and FAAM scores improved significantly from 62.4 to 93.6 and 58.3 to 92.3, respectively, at final follow-up (p<0.001). Mean SNRs and ATFL widths improved insignificantly from 8.49 to 8.21 and 2.07 to 2.15 mm, respectively, at final follow-up (p=0.424, p=0.718). Significant differences in mean SNRs and ATFL widths were found between ipsilateral and contralateral sides (p<0.001, p=0.002). Spearman's correlation analysis revealed no significant association between clinical outcomes and degrees of biological healing of ATFLs based on MRI findings. Conclusion: Despite improvements in clinical outcome measures, the effects of suture-tape augmentation for chronic lateral ankle instability on biological ligament healing were insignificant. In addition, no significant correlation was found between clinical outcomes and degrees of biological healing of ATFLs.

The Correlation Analysis of Ejection Fraction: Comparison of $^{201}Tl$ gated Myocardial Perfusion SPECT and Echocardiography ($^{201}Tl$ 게이트 심근관류 SPECT 및 심초음파의 좌심실 구혈률 상관관계 비교)

  • Yoon, Soon Sang;Ryu, Jae Kwang;Cha, Min Kyung;Lee, Jong Hun;Kim, Sung Hwan
    • The Korean Journal of Nuclear Medicine Technology
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    • v.16 no.2
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    • pp.49-56
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    • 2012
  • Purpose : Gated myocardial perfusion SPECT provides not only myocardial perfusion status, but various functional parameters of left ventricle (LV). The purpose of this study was to analyze ejection fraction (EF) for correlation and difference between $^{201}Tl$ gated myocardial perfusion SPECT and echocardiography depending on extent of perfusion defect, gender and LV volumes. Materials and Methods : From April 2011 to May 2012, we analyzed 291 patients (male:female =165:126; mean: $64.6{\pm}10.8$ years) who were examined both $^{201}Tl$ gated myocardial perfusion SPECT and echocardiography at less than 7 days apart in our hospital. 101 patients showed perfusion defect and the rest of the people without any defect. We applied automatic analysis (Quantitative gated SPECT, QGS), and calculated EF, End-diastolic volume (EDV) and End-systolic volume (ESV) from Stress (G-Stress) and Rest (G-Rest) studies. And we analyzed the correlation and difference for EF between $^{201}Tl$ gated SPECT and echocardiography. Results : The correlation of LVEF among G-Stress, G-Rest and echocardiography was quite a good (G-Stress vs. G-Rest: r=0.909, G-Stress vs. echocardiography: r=0.833, G-Rest vs. echocardiography: r=0.825). And there were significant differences in EDV, ESV and EF in total patients (p<0.01). The normal group showed significant difference in EF (p<0.01) and the group with perfusion defect also demonstrated significant difference (a group with reversible defect: p<0.01, fixed defect: p<0.01) depending on extent of perfusion defect. We analyzed difference in normal group by gender. In normal group, there was no significant difference (p>0.05) in EF from men. However, there was a significant difference (p<0.01) from women. When we classified two groups by average size of EDV in Korean women, there was no significant difference in a group of above average size of EDV (p>0.05). Conclusion : When compared among Stress and Rest of $^{201}Tl$ gated SPECT and echocardiography, we confirmed that there was a good correlation for LVEF. But there were significant differences among three studies. And extent of perfusion defect, gender and LV volumes are independent determinants of the accuracy of LVEF. So, it is hard to compare and interchange quantitative indices among modalities. We should take additional researches to prove results of our study.

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Minor Stress, Coping Skill and Quality of Life in Patients with Hemodialysis (혈액투석 환자들의 Minor Stress, 대처방식 및 삶의 질)

  • Yang, Jae-Won;Lee, Moon-Soo;Park, Sang-Uk;Oh, So-Young;Ko, Young-Hoon;Kwan, Young-Joo;Joe, Sook-Haeng
    • Korean Journal of Psychosomatic Medicine
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    • v.16 no.1
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    • pp.38-46
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    • 2008
  • Objectives : The purpose of this study is to investigate the minor stress in daily life related to undergoing hemodialysis and the relationship between minor stresses, coping skills, and subjective quality of life among the patients with end stage renal disease. Methods : Seventy seven patients on hemodialysis were enrolled in this study. Minor stress was assessed with daily stress inventory-Korean version(K-DSI), ways of coping checklist identified the use of the following coping strategies:problem-focused, seek social support, emotion-focused coping and wishful thinking. Socio-demographic data were obtained and World Health Organization-Quality of Life Scale(brief form) was also administered to subjects. Results : Participants mean age was $55.92{\pm}13.71$ years. The mean of the event, impact and impact/event (I/E) ratio scores of K-DSI were $29.06{\pm}21.57$, $88.69{\pm}75.88$ and $2.92{\pm}1.11$, respectively. These scores were much higher than normative data of K-DSI. Among the 5 categories of this inventory, the scores of cognitive stressors were highest. 5 categories of the inventory showed positive relationship with way of coping subscales, which showed coefficient of correlation between 0.259(p<.01) and 0.495(p<.001). However, no significant correlation was found between minor stress subscales and quality of life. Hemodialysis patients in our study used more emotional-focused coping methods, which was considered as passive way of cope than problem-orientated coping methods. Conclusion : The main findings of this study indicated that patients on hemodialysis showed higher level of perceived minor stress than normal population. The patients treated with hemodialysis tend to use passive way of coping primarily. For assessing the stress in patients on hemodialysis, clinician has to consider both level of perceived minor stress and the ways of coping the patients primarily use.

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Arthroscopic Anterior Cruciate Ligament Reconstruction using Fresh Frozen Achilles Allograft - Clinical results, 2nd look Arthroscopic and Histologic findings - (신선 동결 아킬레스 동종건을 이용한 전방 십자 인대 재건술 - 임상적 결과, 2차 관절경 및 조직학적 소견 -)

  • Chun Churl Hong;Ha Dae Ho;Choi Min Kyu;You Son Soo
    • Journal of the Korean Arthroscopy Society
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    • v.5 no.1
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    • pp.7-12
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    • 2001
  • Purpose : We observed usability of allograft by evaluating the clinical results, second look arthroscopic and histologic findings at last follow up after anterior cruciate ligament(ACL) reconstruction using by fresh frozen Achilles allograft. Materials and Methods : We analyzed in 58 patients(59 cases) by subjective and objective parameters, Telos stress arthrometer and Modified Feagin Scoring System. The average age and follow up period was 25 years(ranging from 18 to 49 years), and 15 months(ranging from 12 to 19 months). Among them we studied second look arthroscopic and histologic findings in 16 patients. Results : The mean Lysholm Score wits improved from 60 to 88.2 as well the anterior translation was improved from 7.1 min to 2.3mm at last follow up. The second look arthroscopic findings were close to normal in ligament thickness, tension and showed revasculization at the holly attachment site. Light microscope(LM) findings showed dense cellularity like a normal ligament. In electron microscope(EM) collagen fibrils showed parallel arrangement longitudinally and unimodal pattern diameter close to normal tissue in the transverse section. Conclusion : We think that the fresh frozen Achilles allograft is a good substitution of autograft in cruciate ligament reconstruction.

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Eating habits, obesity related behaviors, and effects of Danhak exercise in elderly Koreans

  • Ha, Ae-Wha;Kim, Jong-Hyun;Shin, Dong-Joo;Choi, Dal-Woong;Park, Soo-Jin;Kang, Nam-E;Kim, Young-Soon
    • Nutrition Research and Practice
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    • v.4 no.4
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    • pp.295-302
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    • 2010
  • The aims of this study were to evaluate obesity-related dietary behaviors and to determine long-term exercise effects on obesity and blood lipid profiles in elderly Korean subjects. A total of 120 subjects, aged 60-75 yr, were recruited, and obesity-related dietary behaviors were determined. An exercise intervention was conducted with 35 qualified elderly females for 6 months, and body composition and blood lipids were measured 6 times at 4 week intervals. At baseline, mean BMI ($kg/m^2$) was 24.8 for males and 23.1 for females. The females had better eating habits than the males and were more concerned with reading nutrition labels on food products (P < 0.001); they also preferred convenience foods less than the male subjects (P < 0.05). Obese individuals were more likely than overweight or normal weight individuals to misperceive their weight (P < 0.001). Those with a high BMI responded feeling more depressed (P < 0.01), lacking self-confidence (P < 0.01), and feeling isolated (P < 0.01) as well as having more difficulty doing outdoor activities (P < 0.01). After exercise, body fat (%) and WHR were significantly reduced (P < 0.05), while body weight and BMI were also decreased without statistical significance. Total cholesterol and blood HDL were significantly improved (207.1 mg/dl vs. 182.6 mg/dl, HDL: 45.6 mg/dl vs. 50.6 mg/dl, P < 0.05). Other benefits obtained from exercise were improvements in self-confidence (26.4%), movement (22.6%), stress-relief (18.9%), and depression (13.2%). In conclusion, elderly females had better eating habits and were more concerned with nutrition information and healthy diets compared to elderly males. However, misperceptions of weight and obesity-related stress tended to be very high in females who were overweight and obese, which can be a barrier to maintain normal weight. Long-term Danhak practice, a traditional Korean exercise, was effective at reducing body fat (%) and abdominal obesity, and improved lipid profiles, self-confidence, and stress.

Supplementing punicalagin reduces oxidative stress markers and restores angiogenic balance in a rat model of pregnancy-induced hypertension

  • Wang, Yujue;Huang, Mengwei;Yang, Xiaofeng;Yang, Zhongmei;Li, Lingling;Mei, Jie
    • The Korean Journal of Physiology and Pharmacology
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    • v.22 no.4
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    • pp.409-417
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    • 2018
  • Pre-eclampsia (PE) is a pregnancy disorder that is characterised by severe hypertension and increased risks of foetal and maternal mortality. The aetiology of PE not completely understood; however, maternal nutrition and oxidative stress play important roles in the development of hypertension. The treatment options for PE are currently limited to anti-hypertensive drugs. Punicalagin, a polyphenol present in pomegranate juice, has a range of bioactive properties. The effects of supplementation with punicalagin on angiogenesis and oxidative stress in pregnant rats with induced hypertension were investigated. The pregnant rats were randomly divided into five experimental groups (n=12 per group). Hypertension was induced using an oral dose of NG-nitro-L-arginine methyl ester (L-NAME, 50 mg/kg/day) on days 14-19 of pregnancy. Punicalagin (25, 50 or 100 mg/kg) was given orally on days 14-21 of pregnancy. Punicalagin treatment at the tested doses significantly reduced diastolic, systolic, and mean arterial blood pressure in L-NAME treated rats from day 14. Punicalagin also restored angiogenic balance by increasing the expression of vascular endothelial growth factor and downregulating vascular endothelial growth factor receptor-1/fms-like tyrosine kinase-1. Punicalagin, significantly increased the placental nitric oxide levels as compared to PE group. The increased levels of oxidative stress in rats with PE were markedly decreased by treatment with punicalagin. Punicalagin at the tested doses markedly (p<0.05) enhanced the placental antioxidant capacity in L-NAME-treated rats. The raised catalase activity observed following L-NAME induction was significantly (p<0.05) and restored to normal activity levels in punicalagin treatment. Further, 100 mg dose of punicalagin exhibited higher protective effects as compared to lower doses of 25 and 50 mg. This study shows that supplementation with punicalagin decreased blood pressure and oxidative stress and restored angiogenic balance in pregnant rats with induced PE.