• Title/Summary/Keyword: Difference-in-Differences Method

Search Result 2,171, Processing Time 0.042 seconds

Dose Comparison of Treatment Plans Using Different Ir-192 Sources and Treatment Planning Systems for Intracavitary HDR Brachytherapy (고선량률 강내 근접치료에 사용되는 Ir-192 선원과 치료계획 시스템간의 계산선량 비교)

  • Park, Dong-Wook;Kim, Young-Seok;Park, Sung-Ho;Choi, Eun-Kyung;Kim, Jong-Hoon;Lee, Sang-Wook;Song, Si-Yeol;Ahn, Seung-Do;Noh, Young-Joo
    • Progress in Medical Physics
    • /
    • v.20 no.1
    • /
    • pp.1-6
    • /
    • 2009
  • For HDR intracavitary brachytherapy with ovoids and a tandem, we compared the dose discrepancy of treatment plans using two different Ir-192 sources (microSelectron, Varian) and generated on two different treatment planning systems (PLATO, BrachyVision). The treatment plans of ten patient treated from Oct. 2007 to Jan. 2008 were selected for these comparisons. For the comparison of dose calculation using different sources, the average discrepancies were $-0.91{\pm}0.09%$, $-0.27{\pm}0.07%$, $0.22{\pm}0.39%$, and $0.88{\pm}0.37%$ in total treatment time and at B-point and ICRU bladder and rectum reference point, respectively. Comparing the two systems, the average dose discrepancies between treatment planning programs were $-0.22{\pm}0.42%$, $-0.25{\pm}0.29%$, $-0.23{\pm}0.63%$, and $-0.17{\pm}0.76%$, and the average dose discrepancies between positioning methods (PLATO with film and BrachyVision with digitial image) were $-0.61{\pm}0.59%$, $-0.77{\pm}0.45%$, $-0.72{\pm}1.70%$, and $0.35{\pm}2.82%$ at A-point, B-point, and ICRU bladder and rectum reference points, respectively. The rectal dose discrepancies between two systems were reached 5.87%. The difference in the dwell position expected by each TPS are mainly affected by the differences in the positioning method in TPSs and have an effect on dose calculations of rectal and bladder located in AP direction.

  • PDF

Change of Volume of Isoflow in Pneumoconiosis Patients with Small Opacity (소음영 진폐증 환자에서의 등기류용량(Volume of Isoflow)의 변화)

  • Oh, Sang-Yong;Kim, Jee-Won;Jung, Chang-Young;Kim, Kyung-Ah;Yun, Im-Goung
    • Tuberculosis and Respiratory Diseases
    • /
    • v.40 no.5
    • /
    • pp.540-547
    • /
    • 1993
  • Backgrounds: The measurement of volume of isoflow has been considered as a sensitive test for detecting small airway diseases showing normal pulmonary function in a routine pulmonary function test. To evaluate the functions of small airway among dust exposed workers, the changes of volume of isoflow were measured and its applicability of managing early stage pneumoconiosis patients was studied. Method: The subjects were 67 male, pneumoconiosis with small opacity and FEV1>80%, FEV1/FVC>75% in spirometry and the controls were 20 male, no dust-exposed office workers. The maximal epiratory volume curves after inhalation of indoor air and $He-O_2$ gas mixtures were measured and ${\Delta}V_{max50},\;{\Delta}V_{max75},\;V_{iso}V/VC$ between the dust exposed and control workers were compaired. Results: 1) There were no significant differences between two group in ${\Delta}V_{max50}$ and ${\Delta}V_{max75}$. But the ratio of $V_{iso}V/VC$ of the subjects was siginificantly higher than that of the control (p<0.01). This study confirms that $V_{iso}V/VC$ is a very useful index in early detection of small airway dysfunction. 2) The ratio of $V_{iso}V/VC$ of the subjects was signigicantly different between only smoker group and mixed group(smoker and nonsmoker). It suggestes that smoking is an important cousative factor of small airway dysfunction. 3) As the profusion of the chest X-ray increased, the rartio of $V_{iso}V/VC$ increased, but no significant difference of $V_{iso}V/VC$ was found between categories of pneumoconiosis. The categories of pneumoconiosis and small airway dysfunction may not be related. 4) No significant relationship was established between the duration of work and the ratio of $V_{iso}V/VC$. Conclusions : It is concluded that the measurement of $V_{iso}V/VC$ is useful to detect small airway dysfuction of early stage pnuemoconiosis patents with small opacities but showing normal pulmonary function in a routine pulmonary function test.

  • PDF

Study on the Various Size Dependence of Ionization Chamber in IMRT Measurement to Improve Dose-accuracy (세기조절 방사선치료(IMRT)의 환자 정도관리에서 다양한 이온전리함 볼륨이 정확도에 미치는 영향)

  • Kim, Sun-Young;Lee, Doo-Hyun;Cho, Jung-Keun;Jung, Do-Hyeung;Kim, Ho-Sick;Choi, Gye-Sook
    • The Journal of Korean Society for Radiation Therapy
    • /
    • v.18 no.1
    • /
    • pp.1-5
    • /
    • 2006
  • Purpose: IMRT quality assurance(Q.A) is consist of the absolute dosimetry using ionization chamber and relative dosimetry using the film. We have in general used 0.015 cc ionization chamber, because small size and measure the point dose. But this ionization chamber is too small to give an accurate measurement value. In this study, we have examined the degree of calculated to measured dose difference in intensity modulated radiotherapy(IMRT) based on the observed/expected ratio using various kinds of ion chambers, which were used for absolute dosimetry. Materials and Methods: we peformed the 6 cases of IMRT sliding-window method for head and neck cases. Radiation was delivered by using a Clinac 21EX unit(Varian, USA) generating a 6 MV x-ray beam, which is equipped with an integrated multileaf collimator. The dose rate for IMRT treatment is set to 300 MU/min. The ion chamber was located 5cm below the surface of phantom giving 100cm as a source-axis distance(SAD). The various types of ion chambers were used including 0.015cc(pin point type 31014, PTW. Germany), 0.125 cc(micro type 31002, PTW, Germany) and 0.6 cc(famer type 30002, PTW, Germany). The measurement point was carefully chosen to be located at low-gradient area. Results: The experimental results show that the average differences between plan value and measured value are ${\pm}0.91%$ for 0.015 cc pin point chamber, ${\pm}0.52%$ for 0.125 cc micro type chamber and ${\pm}0.76%$ for farmer type 0.6cc chamber. The 0.125 cc micro type chamber is appropriate size for dose measure in IMRT. Conclusion: IMRT Q.A is the important procedure. Based on the various types of ion chamber measurements, we have demonstrated that the dose discrepancy between calculated dose distribution and measured dose distribution for IMRT plans is dependent on the size of ion chambers. The reason is small size ionization chamber have the high signal-to-noise ratio and big size ionization chamber is not located accurate measurement point. Therefore our results suggest the 0.125 cc farmer type chamber is appropriate size for dose measure in IMRT.

  • PDF

Diurnal Variation and Sleep Pattern in Depressive Patients (우울증 환자의 주간기분변동과 수면 양상)

  • Park, Young-Min;Kim, Leen;Suh, Kwang-Yoon;Joe, Sook-Haeng;Kang, Seung-Gul;Yoon, Ho-Kyung
    • Sleep Medicine and Psychophysiology
    • /
    • v.8 no.1
    • /
    • pp.30-36
    • /
    • 2001
  • Object: Diurnal variation is included in the diagnostic criteria of the major depressive disorder, melancholic specifier. But there has been controversy over whether diurnal variation is an unique depressive symptoms or a symptom related to a change of sleep patterns, or that of another mechanism, when the previous studies are reviewed. We investigated the existence of diurnal variation according to the subtype of depression and whether diurnal variation is charateristic of melancholic depression or not. We also compared sleep variables according to the existence of diurnal variation. Method: We examined diurnal variation, sleep patterns, severity of depression using the Visual Analogue Mood Scale, Pittsburgh Sleep Quality Index, and Hamilton Depression Rating Scale. Patients recorded their mood state on the Visual Analogue Mood Scale twice a day, morning and evening, for diurnal variation. We divided depressive patients into two groups,-diurnal variation group and nondiurnal variation group,-and compared the mood and sleep variables using SPSS. Results: The frequency of diurnal variation is not significantly different among the subtypes of depression. Significant differences between the diurnal variation group and the nondiurnal variation group existed in middle insomnia and sleep time (p<0.05). In melancholic type, al significant difference between the diurnal variation group and the nondiurnal variation group was noticed in PSQI total, sleep latency, sleep disturbances, daytime dysfunction as well as middle insomnia and sleep time (p<0.05). Conclusions: Diurnal variation existed in other types of depression as well as melancholic type. The results showed that diurnal variation was not a specific symptom of melancholic type, and existence of diurnal variation might be related to sleep patterns.

  • PDF

Anastomotic Leakage and Stricture Relating to Anastomotic Level and Methods in Esophageal Resection and Reconstruction for Esophageal Cancer (식도암에 있어서 식도 절제술 및 재건술 후 문합 위치와 방법에 따른 문합 부위 누출과 협착)

  • Shin Hong Ju;Kim Chong Wook;Park Soon Ik;Kim Yong Hee;Kim Dong Kwan;Park Seung Il
    • Journal of Chest Surgery
    • /
    • v.39 no.3 s.260
    • /
    • pp.208-213
    • /
    • 2006
  • Background: The prevalence of anastomotic complication is related to anastomotic procedure or site in esophageal cancer operation. We studied the anastomotic leakage and stricture related to the anastomotic procedure & site in patients who received the esophageal resection and reconstruction for esophageal cancer. Material and Method: The anastomotic procedure, site and complication of 321 patients who received the esophageal reconstruction from August 1993 to May 2003 were investigated. Mean age was 64.5$\pm$4.9 (37${\~}$94) years, 300 patients ($93.5\%$) were male and 21 patients were female ($6.5\%$). Result: There were 7 anastomotic leakages ($2.2\%$) and no difference in anastomotic site (cervical anastomosis $4.1\%$, thoracic anastomosis $1.6\%$) and procedure (stapler technique $1.6\%$, semi-staple technique $9.1\%$, hand-sewn technique $0.0\%$). There were 52 anastomotic strictures ($16.2\%$), differences in sites (cervical anastomosis $2.7\%$, thoracic anastomosis $20.2\%$) (p < 0.001) and procedure (stapler technique $20.0\%$, semi-stapler technique $3.0\%$, hand-sewn technique $4.7\%$). And the stapler technique showed higher stricture rate (p < 0.001). Conclusion: Anastomotic technique was less related to anastomotic leakage in esophageal reconstruction for esophageal cancer. However, stapler technique had higher stricture rate than other techniques. Therefore, we suggest that the anastomotic technique be improved to reduce anastomotic stricture.

Effects of Glue Sniffing on Weight Increase or Central Nervous System of Young Rat (반복된 본드 흡입이 백서의 정상발육에 의한 체중증가와 중추신경계에 미치는 영향)

  • Kim, Heon;Kim, Sun-Min;Cho, Soo-Hun
    • Journal of Preventive Medicine and Public Health
    • /
    • v.26 no.2 s.42
    • /
    • pp.222-230
    • /
    • 1993
  • Industrial glues, known as 'Bonds' in Korea, contain many kinds of organic solvents, and glue sniffing of youths became one of the social problems in Korea. Mixed exposures to solvents by glue sniffing may induce chronic toxicities different from those by exposures to solvents of single component. To test effects of the glue sniffing on weight gain or central nervous system, two groups of 20 male Sprague-Dawley rats were exposed to air(control group) or vapors of the glues to narcotic status(exposed group), and weight check, tail flick test, hot plate test, rotarod treadmill test were done on the 14th,24th, 36th, 45th, 53rd, 86th, 102nd, 117th, 134th and 151st days after the first exposure. On the 188th day, their brains were excised and examined by a pathologist. Weight gain, controlled against time change, showed significant difference between the groups, but response times in tail flick test, hot plate tests, and rotarod treadmill test didn't. In pathological examination with blind method, no macroscopic or microscopic differences were found between the two groups. These results suggests that organic lesion in central nervous system may not ensue glue sniffing, but, before firm conclusion, more studies in various exposure conditions should be followed.

  • PDF

Comparison of Standard Culture Method and Real-time PCR Assay for Detection of Staphylococcus aureus in Processed and Unprocessed Foods (가공식품과 비가공식품에서의 황색포도상구균 검출을 위한 배지법과 Real-time PCR법의 비교)

  • Lee, Jae-Hoon;Song, Kwang-Young;Hyeon, Ji-Yeon;Hwang, In-Gyun;Kwak, Hyo-Sun;Han, Jeong-A;Chung, Yun-Hee;Seo, Kun-Ho
    • Food Science of Animal Resources
    • /
    • v.30 no.3
    • /
    • pp.410-418
    • /
    • 2010
  • Staphylococcus aureus is one of the major pathogens that can cause staphylococcal infection and food poisoning. In this study, we compared conventional culture methods and real-time PCR for detection of S. aureus in artificially inoculated milk, sausage, raw pork, and vegetable salad. The performance of a coagulase test for confirming S. aureus was also compared with a colony PCR test. Bulk food samples (500 g each) were artificially inoculated with S. aureus and divided into 20 samples (25 g or mL each). All samples were added to tryptic soy broth (225 mL/sample) with 10% NaCl and incubated at $37^{\circ}C$ for 24 h. After the enrichment, broth cultures were streaked onto Baird-Parker (BP) agar with egg yolk tellulite, and incubated at $37^{\circ}C$ for 24 h. In addition, 1 mL of broth cultures was collected to perform real-time PCR. Two suspicious colonies from the BP agar were picked up and plated on nutrient agar and incubated at $37^{\circ}C$ for 24 h followed, by a coagulase confirmation test and a colony PCR analysis. There were no statistical differences between culture methods and realtime PCR in food samples with low background microflora, such as milk and sausage. However, a significant statistical difference was found between the culture methods and real-time PCR for raw pork and vegetable salad. Furthermore, the colony PCR test of the presumptive colonies on BP agar for confirming S. aureus is more accurate and efficient than the coagulase test for unprocessed foods.

The Analysis on Inquiry Tendency of Elementary Science Textbooks by Curriculum Period: Focusing on the Comparison of Results of Previous Studies Using Romey's Method (초등 과학 교과서의 교육과정 시기별 탐구 성향 비교 분석: Romey 분석법을 이용한 선행 연구 결과 비교를 중심으로)

  • Myoung-Duk Jang
    • Journal of the Korean Society of Earth Science Education
    • /
    • v.16 no.2
    • /
    • pp.166-181
    • /
    • 2023
  • The purpose of this study is to examine the change and appropriateness of inquiry tendency in elementary science textbooks by national curriculum period by comparing previous researches that reported Romey's Involvement Index in the science textbook and other subject textbooks. The results of the study are as follows: First, for the text index (T), the value of science textbooks by curriculum tends to continue to decline overall. The value of science textbook based on the 3rd curriculum is judged to be extremely inquiry oriented and the value of the textbooks based on the 2007 and 2015 revised curriculum are the values judged as somewhat authoritative textbook and as a textbook at the appropriate level of inquiry, respectively. There is no significant difference compared to the T values of other subject textbooks since the 2007 revised curriculum; Second, the index of figures and diagrams in the text (FD) of science textbooks also continues to decline by curriculum periods. In particular, the FD value of science textbook of the 2015 revised period is judged to be a authoritative textbook, which is lower than the value of other subject textbooks; Third, in the case of the activity index (A), it gradually decreases from the third curriculum to the 2015 revised curriculum, but it is judged as textbooks suitable for inquiry. However, after the 7th curriculum, the value of A is generally lower than those of other subject textbooks; Fourth, for the index of the questions at the ends of chapters (Q), the value of Q is reported to be extremely limited compared to the aforementioned three indices(T, FD and A), which may be mainly due to differences in the composition of science textbooks by curriculum period.

Evaluation of Genetic Safety in Genome-editing Rice Through Comparative Analysis of Genetic and Agronomic Traits (유전적 특성과 농업형질의 비교분석을 통한 유전자 교정 벼의 안전성 평가)

  • Seung-Kyo Jeong;Dohyeong Gwon;Bae-Hyeon Lee;Jeong-Hwan Suh;Rahmatullah Jan;Jae-Ryoung Park;Taehun Ryu;Kyung-Min Kim
    • Journal of Life Science
    • /
    • v.34 no.8
    • /
    • pp.567-575
    • /
    • 2024
  • New breeding techniques (NBT) recognize specific DNA sequences and remove, modify, or insert DNA at a desired location, and can be used to treat genetic diseases in humans or to improve the traits of livestock or crops. In this study, we conducted a comparative analysis of various agricultural traits and assessed the safety of gene transferability in third-generation genome-editing rice (OsCKq1-G3) with T and G nucleotide insertions developed using the CRISPR/Cas9 SDN-1 method, in comparison to its parental line (Oryza sativa L., cv Ilmi). The analyzed traits included heading date, culm length, panicle length, tiller number, yield, germination rate, viviparous germination rate, shattering, after wintering seed viability, the presence of toxins and allergens. The target trait, heading date, exhibited a high significant difference of approximately 5 days. Culm length, panicle length, tiller number, yield showed no significant differences compared to the parental line. No T-DNA bands indicating gene transfer were detected. In the third generation of genome-edited rice, the T-DNA was confirmed to be eliminated as successive generations advanced through self-pollination. Through the analysis of germination rate, viviparous germination rate, shattering, and after wintering viability, we confirmed that the genome-editing rice has no potential for weediness. The ORF and amino acid sequences of the genome-editing rice did not reveal any toxins and allergens. The results of this study can be utilized as important data for the environmental risk assessment of genome-editing rice.

Bioavailability of Aspartic Acid Chelated Iron on Iron-deficient Rats (아스파르트산 킬레이트 철분의 철분 결핍쥐에서의 생물학적 유용성)

  • Park, Myoung-Gyu;Ha, Tae-Yul;Shin, Kwang-Soon
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.40 no.12
    • /
    • pp.1720-1725
    • /
    • 2011
  • Aspartic acid chelated iron (Asp-Fe) was synthesized by a new method using calcium carbonate, aspartic acid, and ferrous sulfate. This study was carried out to investigate the bioavailability of Asp-Fe in iron-deficient rats. We divided the rats into four experimental groups. The first was the normal diet control group, or NC. The second was the no treated control group of iron-deficient (ID) rats, or ID+C. The third was the heme-iron (heme-Fe) treated group of ID rats, ID+heme-Fe. And the fourth was the Asp-Fe treated group of ID rats, or ID+Asp-Fe. There were no differences among any of the experimental groups in diet consumption, change of body weight, or the weight of the livers, kidneys, or spleens. After 7 days of feeding, the iron content in the sera of the ID+Asp-Fe group (175.2 ${\mu}g$/dL) and the ID+heme-Fe group (140.8 ${\mu}g$/dL) were significantly higher than that of the ID-C group (96.1 ${\mu}g$/dL). The total iron binding capacity (TIBC) of the ID+Asp-Fe group (735.4 ${\mu}g$/dL) was significantly normalized compared to the ID+C group (841.9 ${\mu}g$/dL) or ID+heme-Fe group (824.6 ${\mu}g$/dL). The hematocrit level of the ID+Asp-Fe group was increased to normal levels, but there was no statistical difference among ID groups. The absorption ratio of heme-Fe was 21.3% and that of Asp-Fe was 50.2%, which indicates a 2.3 times higher ratio in comparison with heme iron. With the above results we found that Asp-Fe seems to be an efficient form of iron to supply iron deficient rats in order to cure them of anemia. Thus, these findings suggest that aspartic acid chelated iron has the potential to serve as a functional food related to iron metabolism.