• Title/Summary/Keyword: Difference-in-differences analysis

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Comparison of Enhanced Dynamic Wedge with Physical Metal Wedge based on the Basic Dosimetric Parameters (선량계측인자에 따른 기능강화동적쐐기와 금속쐐기의 비교)

  • Lee Jeong-Woo;Hong Semie;Choi Kyoung-Sik;Chung Jin-Beom;Choe Bo-Young;Jang Hong Seok;Suh Tae-Suk
    • Progress in Medical Physics
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    • v.16 no.2
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    • pp.70-76
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    • 2005
  • For clinical implementation of Enhanced Dynamic Wedge (EDW), it is necessary to adequately analyze and commission its dosimetric properties in comparison to common physical metal wedge (MTW). This study was implemented with the essential measurements of parameters for clinical application, such as percentage depth dose, peripheral dose, surface dose, effective wedge factor, and wedge profile. In addition, through the comparison study of EDW with open and MTW, the analysis was performed to characterize the EDW. We also compared EDW dose profiles of measured values using chamber array 24 (CA24) with calculated values using radiation treatment planning system. PDDs of EDW showed good agreements between $0.2\~0.5\%$ of open beam, but $2\%$ differences with MTW. In the result of the measurements of peripheral dose, it was shown that MTW was about $1\%$ higher than open field and EDW. The surface doses of $60^{\circ}$ MTW showed 10% lower than the others. We found that effective wedge factor of EDW had linear relationships according to Y jaw sizes and was independent of X jaw sizes and was independent of X jaw sizes and asymmetric Y jaw opening. In comparison with measured values and calculate values from Golden-STT based radiation treatment planning system (RTP system), it showed very good agreement within difference of $1\%$. It could be concluded that EDW is a very reliable and useful tool as a beam modification substitute for conventional MTW.

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Correlation between menton deviation and dental compensation in facial asymmetry using cone-beam CT (Cone-beam CT를 이용한 안면비대칭자에서 이부편위에 따른 치성보상의 양상분석)

  • Park, Soo-Byung;Park, Jeong-Heuy;Jung, Yun-Hoa;Jo, Bong-Hye;Kim, Yong-Il
    • The korean journal of orthodontics
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    • v.39 no.5
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    • pp.300-309
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    • 2009
  • Objective: The purpose of this study was to evaluate the correlation between menton deviation and dental compensation in facial asymmetry. Methods: Tooth axis and distance of first molar and canine to the reference plane were investigated by cone-beam computerized tomography. The subjects consisted of 50 patients with asymmetric mandibles (male 21, female 29, mean age 24.3 years). Control groups were also assessed (male 11, female 9, mean age 25.6 years). Nine measurements (5 linear measurements and 4 angular measurements) were measured in order to evaluate the correlation between menton deviation and the linear and angular difference of first molar and canine in the deviated and none-deviated sides using the defined MPR images. The differences between deviated and non-deviated side, according to menton deviation, were statistically analyzed using stepwise multiple regression analysis. Results: From the result, Menton deviation was negatively correlated with mandibular first molar's angular measurement (${\Delta\angle}LM6$-Mn plane (dev.-ndev.)) and positively with maxillary fist molar's angular measurement (${\Delta\angle}UM6$-FH plane (dev.-ndev.)) (p < 0.01). Two angular measurements (${\Delta\angle}LM6$-Mn plane (dev.-ndev.), ${\Delta\angle}UM6$-FH plane (dev.-ndev.)) explained the variability in menton deviation with a significant $r^2$ value of 0.589. Conclusions: This study suggests that the tooth axis of upper and lower first molars leans towards the deviated side of Menton when there is mandibular asymmetry with Menton deviation.

Comparative Study on Nutrient Intakes, Blood Pressure and Serum Lipid Profile of Korean Adult Men According to Smoking Status (성인 남자의 흡연상태에 따른 영양섭취, 혈압, 혈액 성상 및 지질패턴 비교연구)

  • Choi, Mi-Kyeong;Cho, Hye-Kyung;Sung, Chung-Ja
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.35 no.2
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    • pp.164-170
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    • 2006
  • The purpose of this study was to compare the nutrient intakes, blood pressure, and biochemical values and lipid profile in blood according to smoking status. Subjects were recruited from Korean adult men, which included non-smoker (n=47), smoker (n=58), and ex- smoker (n=44) . Anthropometrical measurement, blood pressure measurement, dietary intake assessment using 24-hour recall method, and blood collection and analysis were conducted. The average age, height, weight, and BMI of the subject were 54.7 years, 165.8 cm, 67.3 kg, and $24.5\;kg/m^2 $, respectively. There was no significant difference in general characteristics among three groups. The mean daily intakes of energy and protein were 1740.9 kcal and 69.6 g. The daily folate intake of the smoker was significantly lower than that of the non- smoker or ex-smoker. However, cholesterol intake of the smoker was significantly higher than two groups. The daily total food intake was 1250.0 g for non-smoker, 1180.1 g for smoker, and 1237.5 g for ex-smoker. The mushrooms intake in the smoker was significantly lower than that in the ex - smoker. However, eggs intake of the smoker was significantly higher than two groups. The RBC count and serum GOT/GPT of the subjects were $4598.2\times1000/mm^3$ and 27.3/27.3 U/L. The WBC count, hematocrit and hemoglobin of the smoker were significantly higher than those of the non-smoker and ex-smoker. Blood pressure and serum lipids of the subjects were 128.3/75.5 mmHg for SBP/DBP, 180.2 mg/dL for total cholesterol, 160.8 mg/dL for triglyceride, 41.5 mg/dL for HDL-cholesterol, 106.5 mg/dL for LDL-cholesterol, and 3.5 for atherogenic index. Especially serum triglyceride of smoker was significantly higher than that of non-smoker. The above results revealed that some nutrient intakes, such as folate and cholesterol, and hematological findings, and serum triglyceride of the smoker were different from non-smoker. However, these differences were recovered to non-smoking status by prohibition of smoking. Therefore, in order to stop smoking, the effect of smoking on nutritional and health status should be informed to smoker and more systematic study should be conducted.

Comparison of Clinical Usefulness between N-13 Ammonia PET/CT and Tc-99m Sestamibi SPET in Coronary Artery Disease (관상동맥질환에서 N-13 암모니아 PET/CT와 Tc-99m 세스타미비 SPECT의 임상 유용성 비교)

  • Kong, Eun-Jung;Cho, Ihn-Ho;Chun, Kyung-Ah;Won, Kyu-Chang;Lee, Hyung-Woo;Park, Jeong-Sun;Shin, Dong-Gu;Kim, Young-Jo;Shim, Bong-Seop
    • Nuclear Medicine and Molecular Imaging
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    • v.42 no.5
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    • pp.354-361
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    • 2008
  • Purpose: N-13 ammonia uptake and retention in the myocardium is related to perfusion and metabolism. There are several potential advantages of N-13 ammonia positron emission tomography (PET) to detect myocardial ischemia, such as higher spatial resolution, greater counting efficiencies, and robust attenuation correction. But there are few reports comparing Tc-99m myocardial perfusion single photon emission tomography (MPS) and N-13 ammonia PET. We thus compared adenosine stress N-13 ammonia PET/CT and Tc-99m sestamibi MPS in patients with suspected coronary artery stenosis. Materials and Methods: Seventeen patients (male 13 : $63{\pm}11$ years old) underwent adenosine stress N-13 ammonia PET/CT (Discovery ST, GE), Tc-99m sestamibi MPS (dual head gamma camera, Hawkeye, GE) and coronary angiography within 1 week. N-13 ammonia PET/CT and Tc-99m sestamibi MPS images were assessed with a 20-segment model by visual interpretation and quantitative analysis using automatic quantitative software (Myovation, GE). Results: Both sensitivities and specificities of detecting an individual coronary artery stenosis were higher for N-13 ammonia PET/CT than Tc-99m sestamibi MPS (PET/CT: 91%/89% vs MPS: 65%/82%). N-13 ammonia PET/CT showed reversibility in 52% of segments that were considered non-reversibile by Tc-99m sestamibi MPS. In the 110 myocardial segments supplied by the stenotic coronary artery, N-13 ammonia PET/CT showed higher count densities than Tc-99m MPS on rest study (p < 0.01), and the difference of count density between the stress and the rest studies was also larger on N-13 ammonia PET/CT. Conclusion: Adenosine stress N-13 ammonia PET/CT had higher diagnostic sensitivity and specificity, more reversibility of perfusion defects and greater stress/rest uptake differences than Tc-99m sestamibi MPS. Accordingly, N-13 ammonia PET/CT might offer better assessment of myocardial ischemia and viability.

Differences in Sodium-Intake Related Dietary Behaviors and Correlation Analysis According to Salty Taste Preference of University Students in Busan Area (부산지역 대학생의 짠맛 선호도에 따른 소금 섭취 식행동 차이와 상관성 분석)

  • Kang, Min-Ji;Choi, Ki-Bo;Lyu, Eun-Soon
    • Korean journal of food and cookery science
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    • v.31 no.4
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    • pp.477-484
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    • 2015
  • The objective of this study was to investigate the awareness of the meaning of a low-sodium diet as well as the self-reported preference of saltiness and sodium-intake related dietary behaviors for university students in Busan. A survey was conducted with 977 students (male: 512, female: 465). For the self-reported preference of saltiness, 45.8% of the participants reported 'moderate' preference, 35.3% reported 'salty' preference, and 18.8% reported 'unsalty' preference. Males had significantly higher scores than females (p<0.01). Regarding awareness of the meaning of a low-sodium diet, 20.8 % of the students did not recognize the phraseand, males had significantly lower awareness than females (p<0.01). The 'salty' group had a significantly lower rate than others (p<0.01). Males had significant higher sodium-related dietary behaviors scores than females for the following questions 'I often eat dried seafood and salted seafood', 'I usually eat all the broth in soups or stews' (p<0.01), 'I usually eat a lot of kimchi and salt-pickled vegetables', 'I usually eat soy dip or hot pepper dip with sushi and fritters' (p<0.05). Mean scores for sodium-related dietary behaviors by self-reported preference of saltiness were 2.49/5.00 (unsalty), 2.87/5.00 (moderate), and 3.19/5.00 (salty), respectively. There was a statistically significant difference between the groups (p<0.01). The lower the scores for the self-reported preference of saltiness, the lower the scores for sodium intake-related dietary behaviors (p<0.01). The average score for sodium-related dietary behaviors in the group familiar with the meaning of a low-sodium diet was significantly lower than that of the group that 'did not know' (p<0.01).

Comparison of Anisotropic Analytic Algorithm Plan and Acuros XB Plan for Lung Stereotactic Ablative Radiotherapy Using Flattening Filter-Free Beams (비편평화여과기 빔을 이용한 폐 정위절제방사선치료를 위한 AAA와 Acuros XB 계산 알고리즘의 치료계획 비교)

  • Chung, Jin-Beom;Eom, Keun-Yong;Kim, In-Ah;Kim, Jae-Sung;Lee, Jeong-Woo;Hong, Semie;Kim, Yon-Lae;Park, Byung-Moon;Kang, Sang-Won;Suh, Tae-Suk
    • Progress in Medical Physics
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    • v.25 no.4
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    • pp.210-217
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    • 2014
  • This study investigated the dosimetric effects of different dose calculation algorithm for lung stereotactic ablative radiotherapy (SABR) using flattening filter-free (FFF) beams. A total of 10 patients with lung cancer who were treated with SABR were evaluated. All treatment plans were created using an Acuros XB (AXB) of an Eclipse treatment planning system. An additional plans for comparison of different alagorithm recalcuated with anisotropic analytic algorithm (AAA) algorithm. To address both algorithms, the cumulative dose-volume histogram (DVH) was analyzed for the planning target volume (PTV) and organs at risk (OARs). Technical parameters, such as the computation times and total monitor units (MUs), were also evaluated. A comparison analysis of DVHs from these plans revealed the PTV for AXB estimated a higher maximum dose (5.2%) and lower minimum dose (4.2%) than that of the AAA. The highest dose difference observed 7.06% for the PTV $V_{105%}$. The maximum dose to the lung was also slightly larger in the AXB plans. The percentate volumes of the ipsilateral lung ($V_5$, $V_{10}$, $V_{20}$) receiving 5, 10, and 20 Gy were also larger in AXB plans than for AAA plans. However, these parameters were comparable between both AAA and AXB plans for the contralateral lung. The differences of the maximum dose for the spinal cord and heart were also small. The computation time of AXB plans was 13.7% shorter than that of AAA plans. The average MUs were 3.47% larger for AXB plans than for AAA plans. The results of this study suggest that AXB algorithm can provide advantages such as accurate dose calculations and reduced computation time in lung SABR plan using FFF beams, especially for volumetric modulated arc therapy technique.

Signs and symptoms of temporomandibular disorders in instrumental performers (악기연주자의 측두하악장애 징후와 증상)

  • Jang, Jae-Young;Choi, Young-Chan;Bae, Jung-Hee;Kim, Seong-Taek
    • Journal of Dental Rehabilitation and Applied Science
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    • v.31 no.2
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    • pp.86-95
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    • 2015
  • Purpose: The aim of the study was to evaluate the subjective symptoms and clinical signs through the TMD-questionnaire, clinical examination and radiography against the many instrumental performers and to investigate the association between playing instruments and TMDs. Materials and Methods: A total of 803 instrumental performers received TMD-related questionnaire and evaluations of prevalence and disease distribution were performed. Among those who reported at least one symptom of TMD, 70 volunteers visited in clinic then received clinical examination and radiography for diagnosis and evaluations of prevalence and disease distribution were performed. 70 subjects were divided into three groups as woodwind, brass wind, string. Comparative analysis of disease distribution was performed. Results: Among 803 instrumental performers, 610 people (75.97%) were reported to one or more symptoms of TMD. The most frequent symptom was click (29.68%).70 subjects underwent a clinical examination and radiography survey results, the most frequent symptom was a click (29.75%). Most commonly diagnosed disease was a myofacial pain (30.53%).Comparison of the three groups, a significant difference was not observed in the clinical sign. But among subject symptom, muscle pains howed significant differences in accordance with the Group (P = 0.024). During the 70 people who underwent clinical examination, 66 people (94.3%) showed moderate to severe attrition, mild to severe tongue ridging, mild to severe cheek ridging assigns of parafunction. Conclusion: Instrumental performers showed a high prevalence of TMD and the most of the musicians with temporomandibular disorder had bruxism or clenching habits.

The Relation between Frailty, Social Support, and Health-related Quality of Life in Old-Old Elderly (후기노인의 허약, 사회적 지지, 건강관련 삶의 질 간의 관계)

  • Lee, Jeong Hwa;Kim, Eun Hwi;Suh, Soon Rim
    • 한국노년학
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    • v.38 no.4
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    • pp.891-903
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    • 2018
  • This study investigated the relation between frailty, social support, and health-related quality of life to provide basic data to improve the health-related quality of life of old-old elderly who are a high risk group for frailty. For this descriptive study, one-on-one interviews with structured questionnaires were conducted for elderly aged 75 years or older at elderly welfare facilities in K county from March 01 to 31 in 2016, and a total of 211 elderly were interviewed. The collected data were analyzed by t-test, Pearson's correlation coefficient, and path analysis using SPSS/WIN and AMOS 18.0 program. For the differences between the age groups, those aged over 80 years had a significantly higher frailty (t=-2.51, p=.013) and a lower health-related quality of life than those aged below 80 years (t=3.29, p=.001); however, there was no significant difference in social support (t=1.28, p=.201). The correlation between frailty, social support and health-related quality of life showed that as frailty became higher, social support (r=-.21, p=.003) and health-related quality of life (r=-.65, p<.001) were significantly lower, and health-related quality of life was significantly higher with a higher social support (r=.18, p=.010). As a result of investigating the mediating effects of frailty between social support and health-related quality of life, social support had a significant direct effect on frailty (${\beta}=-.21$, p=.016) and frailty had a significant direct effect on health-related quality of life (${\beta}=-.06$, p=.004); however, social support had no significant direct effect on health-related quality of life (${\beta}=.00$, p=.562). Social support had a significant indirect effect on health-related quality of life and a mediating effect on frailty (${\beta}=.01$, p=.012); therefore, the full mediation effect of frailty between social support and health-related quality of life was verified. Social support prevents frailty, and improving frailty enhances health-related quality of life. Therefore, it is necessary to develop a multifactorial frailty prevention program that includes age-specific social support strategies to improve the health-related quality of life in old-old elderly.

Effects of Fermented Mixed Organic Fertilizer Utilizing By-Products on Soil Properties and the Yield of Organic Lettuce (부산물 활용 발효 유기질비료 처리에 따른 유기 상추 토양 특성 및 수량에 미치는 영향)

  • An, Nan-Hee;Lee, Sang-min;Hwang, Hyun-Young;Park, Sang-Gu;Lee, Cho-Rong
    • Journal of the Korea Organic Resources Recycling Association
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    • v.29 no.3
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    • pp.41-48
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    • 2021
  • This study aimed to develop an alternative organic fertilizer to castor oil cake-based fertilizers. To assess the nutrient effect of the developed fermented mixed organic fertilizers, the yield of lettuce and soil characteristics after growth were analyzed and compared to those of a trial using a mixed expeller cake fertilizer. Two fermented mixed organic fertilizers, FA and FB, each containing 5.0% nitrogen, 2.6% phosphate, and 1.4% potassium, were produced by mixing different ratios of rice bran, dried distillers grains, sesame oil meal, and fish meal. This study was conducted with six trials: untreated, mixed expeller cake fertilizer, and the fermented mixed organic fertilizers FA and FB. Based on the amount of nitrogen fertilization (70 kg ha-1) on the lettuce, the fermented mixed organic fertilizers FA and FB were applied at 100% and 150%, respectively, and the mixed oil cake was applied at 100%. As the amount of treatment increased, there was no significant difference except the number of leaves in FA treatment. The yields from the FA100 and FB100 treatments were 38.2 and 40.8 Mg ha-1, respectively, which was not significantly different from that of the mixed expeller cake fertilizer treatment at 38.3 Mg ha-1. In addition, the nitrogen uptake and utilization efficiency of the lettuce were not significantly different between mixed expeller cake fertilizer and fermented mixed organic fertilizer treatments. Analysis of the chemical properties of the soil after the trial showed that he mixed expeller cake fertilizer treatment showed the lowest pH. There were no significant differences in electrical conductivity, content of soil organic matter, available phosphate, and exchangeable cation among the fertilizer treatments. However, the bacterial and actinomyces density was higher in the soil from the fertilizer trials than in the non-fertilizer trials. These results indicated that the two tested fermented mixed organic fertilizers had nourishing effects and soil characteristics that were similar to those of the mixed expeller cake fertilizer. Thus, farmers can use these fermented mixed organic fertilizers as alternatives to castor oil cakes for the cultivation of organic lettuce.

Needs and Related Factors for Return-to-Work Support in Cancer Survivors (암 경험자의 직장복귀지원에 대한 요구도 및 관련 요인)

  • Lee, Sungwon;Lee, Kwang-Min;Oh, Gyu-Han;Yeom, Chan-Woo;Jung, Sanghyup;Hahm, Bong-Jin
    • Korean Journal of Psychosomatic Medicine
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    • v.28 no.2
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    • pp.126-134
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    • 2020
  • Objectives : The purpose of this study was to investigate the needs for return-to-work support of cancer survivors and related factors in patients with cancer and their caregivers. Methods : 182 patients and 114 caregivers were recruited. Distress Thermometer and Problem List and scale ranging 0~10 measuring the degree of needs for return-to-work support were utilized. The needs for return-to-work support between the patient group and caregiver group (patient's needs evaluated by the caregiver) were compared, and related factors were investigated using logistic regression analysis. Results : 34.6% and 28.1% of patients and caregivers reported return-to-work support of cancer survivors is "very necessary". The degree of needs was 6.60±3.365 points in the patient group and 6.17±3.454 points in the caregiver group, with no significant difference (p=0.282). The needs for return-to-work support evaluated by patients was high when they underwent surgery (OR=2.592, p=0.007), has fertility problems (OR=6.137, p=0.025), has appearance problems (OR=2.081, p=0.041), or has fatigue (OR=2.330, p=0.020). The needs for return-to-work support of patients evaluated by caregivers was high when patients treated with breast cancer (vs respiratory cancer, OR=13.038, p=0.022 ; vs leukemia/lymphoma, OR=4.517, p=0.025 ; vs other cancer, OR=13.102, p=0.019), has work/school problems (OR=4.578, p=0.005), or has depression (OR=3.213, p=0.022). Conclusions : The degree of needs for return-to-work support of cancer survivors was high, and factors related to the needs were different between the two groups. This suggests that return-to-work support of cancer survivors is required, and clinical characteristics, the distress of patients, and differences between patients and their caregivers should be considered in establishing a support plan.