• 제목/요약/키워드: Difference-in-difference Method

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Effects of Preoperative Combined Antiplatelet Agents on the Postoperative Bleeding that Occurs during Off-pump Coronary Artery Bypass Surgery (무심폐기하 관상동맥우회수술에서 아스피린과 Clopidogrel의 수술 전 병합투여가 수술 후 출혈에 미치는 영향)

  • Choi, Kang-Joo;Seong, Hoo-Sik;Kae, Yoe-Kon
    • Journal of Chest Surgery
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    • v.41 no.5
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    • pp.605-609
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    • 2008
  • Background: It is well known that preoperative administration of combined antiplatelet agents can have an impact on the postoperative bleeding, the requirement for transfusion and the need for reexploration during on-pump coronary artery bypass surgery. Yet its effects have not been well evaluated in the case of off-pump coronary artery bypass surgery. Material and Method: We performed a retrospective study of nineteen patients who underwent OPCAB from March 2003 to December 2004. All the patients had taken antiplatelet agents until 12 hours before operation. The patients were divided into bo groups as an aspirin group and a combined (aspirin+clopidogrel) group. The perioperative platelet count, the hemoglobin level, the hematocrit, the prothrombin time and the aPTT were compared between both groups. The amount of postoperative bleeding, the transfusion requirement and the need for re-exploration to control bleeding were also compared between both groups. Result: There was no difference of operation time and the intraoperative ACT between the aspirin group and the combined group. The amount of blood loss through the chest tube for 24 hours was not different between the aspirin group $(697{\pm}271mL)$ and the combined group $(944{\pm}432mL)$. The number of patients who received blood transfusion was also not different between both groups. There was no patient who required reexploration for bleeding control in both groups. The perioperative hemoglobin level and hematocrit were also not different between both groups, but the postoperative hemoglobin level and hematocrit were decreased significantly in the group. Conclusion: The Preoperative combined antiplatelet (aspirin+clopidogrel) therapy group was not different from the aspirin group for the amount of postoperative bleeding, the amount of blood transfusion and the need for reexploration during off-pump coronary artery bypass grafting. This subject needs further evaluation because of small population in our study.

Study on the snack meal management for infants and toddlers and the demand for snack products according to the sustainable dietary style of mothers in Jeonbuk area (전북지역 어머니의 지속가능 식생활유형에 따른 영유아 자녀의 간식관리 및 간식제품에 대한 요구도 조사)

  • Lee, Ji-Eun;Rho, Jeong-Ok
    • Journal of Nutrition and Health
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    • v.53 no.1
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    • pp.39-53
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    • 2020
  • Purpose: The purpose of the study was to examine the snack meal management for infants and toddlers and the demand for snack products according to mothers' sustainable dietary style in the Jeonbuk area. Methods: The participants were 359 mothers in the Jeonbuk area. The data was analyzed using factor analysis, cluster analysis, analysis of variance, and χ2-tests with SPSS v. 25.0. According to the sustainable dietary style, the situation of providing snacks at home, the purchasing behavior for snack products, and the satisfaction and, demand for snack products were investigated. Results: Using the K-clustering method, the sustainable dietary style of the subjects was categorized into 3 clusters. Cluster 1 was the family health-seeking group, cluster 2 was the sustainable dietary trend group, and cluster 3 was the sustainability-interested group. The frequency of snack intakes according to the cluster groups showed a significant difference (p < 0.001). Fruits were the snack item most frequently consumed by all the cluster groups. Approximately 92.8% of mothers had purchased snack products, and 95.2% of the subjects were satisfied with them (p < 0.05). The main reason for satisfaction with the snack products in all the cluster groups was the various kinds of products with considering the growth stage of children. Clusters 2 and 3 required the development of snack products using organic food materials, while cluster 1 required the snack products to be supplemented with various nutrients. Conclusion: It is necessary to develop various snack products according to the sustainable dietary style and the needs of mothers so that these snacks can increase the satisfaction of mothers with the snack products and lead them to better snack purchasing behavior.

The Effect of Mean Brightness and Contrast of Digital Image on Detection of Watermark Noise (워터 마크 잡음 탐지에 미치는 디지털 영상의 밝기와 대비의 효과)

  • Kham Keetaek;Moon Ho-Seok;Yoo Hun-Woo;Chung Chan-Sup
    • Korean Journal of Cognitive Science
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    • v.16 no.4
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    • pp.305-322
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    • 2005
  • Watermarking is a widely employed method tn protecting copyright of a digital image, the owner's unique image is embedded into the original image. Strengthened level of watermark insertion would help enhance its resilience in the process of extraction even from various distortions of transformation on the image size or resolution. However, its level, at the same time, should be moderated enough not to reach human visibility. Finding a balance between these two is crucial in watermarking. For the algorithm for watermarking, the predefined strength of a watermark, computed from the physical difference between the original and embedded images, is applied to all images uniformal. The mean brightness or contrast of the surrounding images, other than the absolute brightness of an object, could affect human sensitivity for object detection. In the present study, we examined whether the detectability for watermark noise might be attired by image statistics: mean brightness and contrast of the image. As the first step to examine their effect, we made rune fundamental images with varied brightness and control of the original image. For each fundamental image, detectability for watermark noise was measured. The results showed that the strength ot watermark node for detection increased as tile brightness and contrast of the fundamental image were increased. We have fitted the data to a regression line which can be used to estimate the strength of watermark of a given image with a certain brightness and contrast. Although we need to take other required factors into consideration in directly applying this formula to actual watermarking algorithm, an adaptive watermarking algorithm could be built on this formula with image statistics, such as brightness and contrast.

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Facial soft tissue measuring analysis of normal occlusion using three-dimensional CT imaging (3차원 CT 영상을 이용한 정상교합자의 안면 연조직 계측 분석)

  • Han, Soo-Yeon;Baik, Hyoung-Seon;Kim, Kee-Deog;Yu, Hyung-Seog
    • The korean journal of orthodontics
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    • v.35 no.6 s.113
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    • pp.409-419
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    • 2005
  • Studies for diagnostic analysis using three-dimensional (3D) CT images are recently in progress and needs for 3D craniofacial analysis are increasing in the fields of orthodontics. It is especially essential to analyze the facial soft tissue after orthodontic treatment and orthognathic surgery. In this study 3D CT images of adults with normal occlusion were taken to analyze the facial soft tissue. Norms were obtained from CT images of adults with normal occlusion (12 males, 11 females) using a computer program named V works 4.0 program. 3D coordinate planes were established using soft tissue Nasion as the reference point and a total of 20 reproducible landmarks of facial soft tissue were obtained using the multiple reconstructive sectional images (axial, sagittal and coronal images) of the V works 4.0 program: soft tissue Nasion, Pronasale, Subnasale, Upper lip center, Lower lip center, soft tissue B, soft tissue Pogonion, soft tissue Menton, Endocanthion (Rt/Lt), Alare lateralis (Rt/Lt), Cheilion (Rt/Lt), soft tissue Gonion (Rt/Lt), Tragus (Rt/Lt), and Zygomatic point (Rt/Lt). According to the established landmarks and measuring method, the 3D CT images of adults with normal occlusion were measured and the normal positional measurements and their Net (${\delta}=\sqrt{{X^2}+{Y^2}+{Z^2}}$) values were obtained using V surgery program, In the linear measurement between landmarks, there was a significant difference between males and females except Na' -Sn and En(Rt)-En(Lt). The normal ranges of Na'-Zy, Na'-Ch and Na'-Go' (facial depth) were obtained, which was difficult to measure by two-dimensional (2D) cephalometric analysis and facial photographs. These data may be used as references for 3D diagnosis and treatment planning for patients with malocclusion and dentofacial deformity.

Relatively Decreased Level of Subjective Daytime Sleepiness and Its Associated Factors in Patients with Primary Insomnia (일차성 불면증 환자에서의 주간 졸림증과 연관된 수면변인에 대한 연구)

  • Lee, Yu-Jin;Lee, Jin-Sung;Sohn, Chang-Ho;Lee, Eun-Hye;Moon, Pil-Sung;Jeong, Do-Un
    • Sleep Medicine and Psychophysiology
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    • v.12 no.2
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    • pp.117-121
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    • 2005
  • Objectives: The purpose of this study was to assess the difference of subjective daytime sleepiness level between primary insomnia patients and healthy control subjects. We also investigated the relationship between subjective daytime sleepiness level and variables of nocturnal polysomnograghic sleep architecture of insomnia patients. Method: Total subjects were 87 patients with primary insomnia diagnosed with polysomnography and 88 normal controls. The daytime sleepiness level in each group was measured by Korean version of Epworth Sleepiness Scale (ESS). The correlations of ESS score and nocturnal polysomnographic variables were calculated in the patient group. Results: Patients with insomnia had the lower ESS scores than the control group. In patients group, the ESS score showed significant negative correlations with total sleep time, sleep efficiency%, and stage 2 sleep time%. The ESS score also showed significant positive correlations with number of awakenings, number of awakenings more than 2 minutes, and wake after sleep onset time. Conclusions: Insomnia patients showed lower level of subjective daytime sleepiness that may indicate their higher alertness comparing to control subjects. Daytime sleepiness of patients with insomnia was associated with polysomnographic variables including total sleep time, sleep efficiency%, stage 2 sleep time% and disrupted continuity of nocturnal sleep.

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Relationship of Hemodynamic Changes during Off-Pump Coronary Bypass Grafting and Their Effects on Postoperative Outcome (심폐바이패스 없이 시행하는 관상동맥 우회수술 중의 혈역학적 변수들의 변화양상 및 수술 후 결과에 미치는 영향)

  • 허재학;장지민;김욱성;장우익;이윤석;정철현
    • Journal of Chest Surgery
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    • v.36 no.8
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    • pp.576-582
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    • 2003
  • During the Off-Pump Coronary Arterial Bypass surgery (OPCAB), the manipulation of the heart can depress cardiac contractility and cause hemodynamic instability. In this study, hemodynamic parameters were measured during operation and the laboratory and clinical data were investigated to evaluate their effects on postoperative outcome. Material and Method: From March 2001 to August 2002, 50 consecutive patients who underwent OPCAB were included in this study. During the same period, total number of CABG was 71 The blood pressure, pulmonary artery pressure, mixed venous oxygen saturation, and cardiac index were measured before manipulation, after application of stabilizer, and at the end of anastomosis. Postoperatively, we measured the cardiac enzymes such as CK-MB, troponin 1 and checked the amount of inotropes required, chest tube drainage, the amount of transfusion, duration of ventilator support, and duration of ICU stay. Result: The number of mean distal anastomoses was 2.8$\pm$0.9 per patient. On elevation and stabilization of the heart, systolic blood pressure was depressed and pulmonary artery pressure was elevated significantly, but during each anastomosis no significant changes were detected. The peak level of cardiac markers was 29.2$\pm$46.7 for CK-MB, 0.69$\pm$0.86 for troponin 1 on postoperative day f. Among the intraoperative hemodynamic parameters, the ischemic change of EKG and bolus injection of inotropes significantly affected the posteroperative cardiac enzymes. But, no difference other than the level of cardiac enzymes between the two groups with or without the ischemic change of EKG and bolus injection of inotropes was noticed. Conclusion: The significant hemodynamic changes occurred when the heart was elevated and stabilized, however during anastomoses there were no significant changes. Serum cardiac enzymes rose significantly in the group that showed the ischemic charge of EKG or needed the bolus injection of inotropes for maintaining hemodynamic stability intraoperatively, but it did not affect the postoperative outcome. In conclusion, the ischemic change of EKG and the need for bolus injection of intropes during operation may be very indicative for probable ischemia.

Change of the Vegetation Due to Soyanggang Dam Construction (소양강댐 건설에 따른 주변 식생의 변화)

  • Choi, Ho;Park, Pil-Sun;Kim, Jae-Geun;Suh, Sim-Eun
    • Journal of Wetlands Research
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    • v.12 no.3
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    • pp.1-13
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    • 2010
  • Most of investigations about the effects of dam construction on the surrounding environments have focused mainly on the change of climate conditions and crop production. In order to research the effect of dam construction on the surrounding vegetation, we chose the Soyanggang dam whose storage capacity is the largest in Korea, and was built 33 years ago. We surveyed and analyzed the surrounding vegetation by using quadrat method and measured the soil moisture content among floodplain (FP), 5m above the flood plain (AFP) and control group (CG) which is 3km far from the lake through ridge. The largest value of mean importance percentage of the canopy~understory layer at FP was Salix koreensis (87.9%) and those of AFP and CG was Quercus mongolica (38.9% and 40.4% respectively) and the largest important percentage of the herb layer at FP was Artemisia capillaris (34.2%) and those of AFP and CG was Oplismenus undulatifolius var. undulatifolius (9.4% and 24.6% respectively). The Shannon-Wiener diversity index of shrub~canopy layer at FP (0.26) was lower than AFP (2.34) and CG (2.23) and there was not any significant difference in the herb layer among three groups. The S${\o}$rensen similarity index between FP and AFP, FP and CG was 0, and that of AFP and CG was relatively high. The highest density of tree and subtree with the DBH level of FP was S. koreensis of 5~10cm (240/ha), and that of AFP and CG was Quercus spp. of 15~20cm (400/ha and 466/ha respectively). And the highest density of seedlings of FP was Pinus densiflora (7,040/ha), and that of AFP and CG was Quercus spp. (720/ha and 400/ha respectively). The soil water content of FP (6.28%) was relatively lower than AFP and CG (11.13% and 10.14% respectively; p<.01). These results indicated that construction of Soyanggang dam changed the vegetation of the floodplain, without showing a change in its upland areas.

Projecting future hydrological and ecological droughts with the climate and land use scenarios over the Korean peninsula (기후 및 토지이용 변화 시나리오 기반 한반도 미래 수문학적 및 생태학적 가뭄 전망)

  • Lee, Jaehyeong;Kim, Yeonjoo;Chae, Yeora
    • Journal of Korea Water Resources Association
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    • v.53 no.6
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    • pp.427-436
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    • 2020
  • It is uncertain how global climate change will influence future drought characteristics over the Korean peninsula. This study aims to project the future droughts using climate change and land use change scenarios over the Korean peninsula with the land surface modeling system, i.e., Weather Research and Forecasting Model Hydrological modeling system (WRF-Hydro). The Representative Concentration Pathways (RCPs) 2.6 and 8.5 are used as future climate scenarios and the Shared Socio-economic Pathways (SSPs), specifically SSP2, is adopted for the land use scenario. The using Threshold Level Method (TLM), we identify future hydrological and ecological drought events with runoff and Net Primary Productivity (NPP), respectively, and assess drought characteristics of durations and intensities in different scenarios. Results show that the duration of drought is longer over RCP2.6-SSP2 for near future (2031-2050) and RCP8.5-SSP2 (2080-2099) for the far future for hydrological drought. On the other hand, RCP2.6-SSP2 for the far future and RCP8.5-SSP2 for the near future show longer duration for ecological drought. In addition, the drought intensities in both hydrological and ecological drought show different characteristics with the drought duration. The intensity of the hydrological droughts was greatly affected by threshold level methods and RCP2.6-SSP2 for far future shows the severest intensity. However, for ecological drought, the difference of the intensity among the threshold level is not significant and RCP2.6-SSP2 for near future and RCP2.6-SSP2 for near future show the severest intensity. This study suggests a possible future drought characteristics is in the Korea peninsula using combined climate and land use changes, which will help the community to understand and manage the future drought risks.

THE COMPARISON OF RELATIVE RELIABILITY ON BIAXIAL AND THREE POINT FLEXURAL STRENGTH TESTING METHODS OF LIGHT CURING COMPOSITE RESIN (광중합형 레진의 3점 굴곡 강도와 이축 굴곡 강도 측정 방법에 대한 상대적 신뢰도의 비교)

  • Seo, Deog-Gyu;Roh, Byoung-Duck
    • Restorative Dentistry and Endodontics
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    • v.31 no.1
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    • pp.58-65
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    • 2006
  • The possibility of applying a hi-axial flexure strength test on composite resin was examined using three point and hi-axial flexure strength tests to measure the strength of the light-cured resin and to compare the relative reliability using the Weibull modulus. The materials used in this study were light-curing restorative materials, $MICRONEW^{TM},\;RENEW^{(R)}$ (Bisco, Schaumburg, USA). The hi-axial flexure strength measurements used the piston-on-3-ball test according to the regulations of the International Organization for Standardization (ISO) 6872 and were divided into 6 groups, where the radius of the specimens were 12mm (radius connecting the 3-balls: 3.75mm), 16 mm(radius connecting the 3-balls: 5mm), and the thickness were 0.5mm, 1mm, 2mn for each radius. The hi-axial flexure strength of the $MICRONEW^{TM}\;and\;RENEW^{(R)}$ were higher than the three point flexure strength and the Weibull modulus value were also higher in all of the bi-axial flexure strength groups, indicating that the hi-axial strength test is relatively less affected by experimental error. In addition, the 2 mm thick specimens had the highest Weibull modulus values in the hi-axial flexure strength test, and the $MICRONEW^{TM}$ group showed no significant statistical difference (p>0.05). Besides the 2mm $MICRONEW^{TM}$ group, each group showed significant statistical differences (p<0.05) according to the thickness of the specimen and the radius connecting the 3-balls. The results indicate that for the 2mm group, the hi-axial flexure strength test is a more reliable testing method than the three point flexure strength test.

Clinical Characteristics and Abnormal p53 Expression of Lung Cancer Associated with Multiple Primary Cancer (다발성 악성종양에 동반된 폐암의 임상 특징과 변이형 p53 발현)

  • Shin, Chang-Jin;Park, Hye-Jung;Shin, Kyeong-Cheol;Shim, Young-Ran;Chung, Jin-Hong;Lee, Kwan-Ho
    • Tuberculosis and Respiratory Diseases
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    • v.47 no.3
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    • pp.331-338
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    • 1999
  • Background: Nearly 10% of cancer patients will develop a second primary cancer within ten years after surgical removal of the primary tumor. The detection of risk factors for developing multiple primary tumors would be important This study was conducted to evaluate the clinical characteristics and abnormal p53 expression of lung cancer associated with multiple primary cancer(MPC). Method: Clinical characteristics and abnormal p53 expression were compared between 20 cases of lung cancer(NSCLC ; 16 cases, SCLC ; 4 cases) associated with MPC and 26 cases of primary non-small cell lung cancer. Result: MPC associated with lung cancer was gastric cancer(8), lung cancer(2), esophageal cancer(2), colon cancer(2), laryngeal cancer(1), bladder cancer(1), small bowel cancer(l), adrenal cancer(1), hepatocellular carcinoma(1), and breast cancer (1) in order. The clinical stage of primary NSCLC was relatively advanced, but NSCLC associated with MPC was even distribution at each stage. The detected incidences of abnormal p53 expressions were 62.5% in NSCLC associated with MPC and 76.9% in primary NSCLC(p>0.05). Conclusion: There was no difference in abnormal p53 expression between non-small cell carcinoma associated with multiple primary cancer and primary non-small cell carcinoma.

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