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A Study on the Fatigue Crack Growth Behavior in Welding Residual Stress Field(I) (용접잔류응력장에서의 피로균열 성장거동에 관한 연구(I))

  • 최용식;김영진;우흥식
    • Journal of the Korean Society of Safety
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    • v.5 no.1
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    • pp.19-29
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    • 1990
  • The objective of this paper is to investigate the effect of residual stresses on the $\Delta$K$\sub$th/ and fatigue crack growth behavior of butt weldments. For this purpose, transverse butt sutmerged arc welding was performed on SM50A steel plate and CT(compact tension) specimens which loading direction is perpendicular to weld bead were selected. Welding residual stresses distribution on the specimen was determined by hole drilling method. The case of crack located parallel to weld bead, the states of as weld and PWHT, $\Delta$K$\sub$th/ of specimens(HAZ, weld zone) was higher than that of the base metal probably because of the compressive residual stresses of crack tip. In low $\Delta$K region, it is estimated that the effects of residual stresses for da/dN are great. In region II, the da/dN of weldments in as weld state was lower than that of the base metal. Though da/dN of Weldments in PWHT state was similar to that of the base metal. The constant of power law, m in two states consisted with the base metal. Therefore , it is estimated that the value of m is not affected by residual stresses. Fatigue crack growth behavior of weldments consisted with the base metal considering the effective stress intensity factor range($\Delta$K$\sub$eff/) included the effect of initial residual stress(Kres). Thus, we can predict the fatigue crack growth behavior of weldment by knowing the distribution of initial residual stress at the crack tip.

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Determination of Nutritive Value of Citrus Tree Leaves for Sheep Using In vitro Gas Production Technique

  • Karabulut, Ali;Canbolat, Onder;Ozkan, Cagri O.;Kamalak, Adem
    • Asian-Australasian Journal of Animal Sciences
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    • v.20 no.4
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    • pp.529-535
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    • 2007
  • The nutritive values of leaves of Citrus grandis, Citrus aurantium, Citrus oranges, Citrus limon, and Citrus deliciosa were evaluated by chemical composition and in vitro gas production techniques. There were significant (p<0.001) differences among citrus species in terms of chemical composition. Crude protein (CP) contents ranged from 123.0 to 148.3 g/kg DM. Neutral detergent fibre (NDF) and acid detergent fibre (ADF) contents were varied with species in the range 219.4-355.4 and 215.0-278.8 g/kg DM respectively. Condensed tannin (CT) contents were ranged from 5.9 to 10.2 g/kg DM. The PEG addition significantly (p<0.001) increased the gas production and some estimated parameters of citrus tree leaves. However, species showed variable responses to polyethylene glycol (PEG) treatment. There were also significant (p<0.001) differences among species in terms of gas production and estimated parameters. The OMD and ME contents of citrus leaves without PEG supplementation were ranged from 66.5 to 73.3% and 9.8 to 10.9 MJ/kg DM respectively. The improvement in gas production, organic matter digestibility (OMD) and metabolizable energy (ME) with PEG emphasized the negative effect of tannins on digestibility. The increase (%) in the estimated OMD and ME contents ranged from 5.5 to 9.8% and 5.7 to 10.2% respectively. All citrus tree leaves studied in this experiment have potential nutritive values indicated by high crude protein content, OMD, ME and low fiber values.

Application of Data Mining Techniques to Explore Predictors of HCC in Egyptian Patients with HCV-related Chronic Liver Disease

  • Omran, Dalia Abd El Hamid;Awad, AbuBakr Hussein;Mabrouk, Mahasen Abd El Rahman;Soliman, Ahmad Fouad;Aziz, Ashraf Omar Abdel
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.1
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    • pp.381-385
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    • 2015
  • Background:Hepatocellular carcinoma (HCC) is the second most common malignancy in Egypt. Data mining is a method of predictive analysis which can explore tremendous volumes of information to discover hidden patterns and relationships. Our aim here was to develop a non-invasive algorithm for prediction of HCC. Such an algorithm should be economical, reliable, easy to apply and acceptable by domain experts. Methods: This cross-sectional study enrolled 315 patients with hepatitis C virus (HCV) related chronic liver disease (CLD); 135 HCC, 116 cirrhotic patients without HCC and 64 patients with chronic hepatitis C. Using data mining analysis, we constructed a decision tree learning algorithm to predict HCC. Results: The decision tree algorithm was able to predict HCC with recall (sensitivity) of 83.5% and precession (specificity) of 83.3% using only routine data. The correctly classified instances were 259 (82.2%), and the incorrectly classified instances were 56 (17.8%). Out of 29 attributes, serum alpha fetoprotein (AFP), with an optimal cutoff value of ${\geq}50.3ng/ml$ was selected as the best predictor of HCC. To a lesser extent, male sex, presence of cirrhosis, AST>64U/L, and ascites were variables associated with HCC. Conclusion: Data mining analysis allows discovery of hidden patterns and enables the development of models to predict HCC, utilizing routine data as an alternative to CT and liver biopsy. This study has highlighted a new cutoff for AFP (${\geq}50.3ng/ml$). Presence of a score of >2 risk variables (out of 5) can successfully predict HCC with a sensitivity of 96% and specificity of 82%.

Can Computed Tomographic Angiography Be Used to Predict Who Will Not Benefit from Endovascular Treatment in Patients with Acute Ischemic Stroke? The CTA-ABC Score

  • Kwak, Hyo-Sung;Park, Jung-Soo
    • Journal of Korean Neurosurgical Society
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    • v.63 no.4
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    • pp.470-476
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    • 2020
  • Objective : The objective of this study was to develop a score to predict patients with acute ischemic stroke (AIS) who will not benefit from endovascular treatment (EVT) using computed tomographic angiography (CTA) parameters. Methods : The CTA-ABC score was developed from 3 scales previously described in the literature: the Alberta Stroke Program Early CT Score (0-5 points, 3; 6-10 points, 0), the clot burden score (0-3 points, 1; 4-10 points, 0), and the leptomeningeal Collateral score (0-1 points, 2; 2-3 points, 0). We evaluated the predictive value of CTA parameters associated with symptomatic intracranial hemorrhage (sICH) or malignant middle cerebral artery infarction (MMCAI) after EVT and developed the score using logistic regression coefficients. The score was then validated. Performance of the score was tested with an area under the receiver operating characteristic curve (AUC-ROC). Results : The derivation cohort consisted of 115 and the validation cohort consisted of 40 AIS patients. The AUC-ROC was 0.97 (95% confidence interval [CI], 0.94-0.99; p<0.001) in the derivation cohort. The proportions of patients with sICH and/or MMCAI in the derivation cohort were 96%, 73%, 6%, and 0% for scores of 6, 5, 1, and 0 points, respectively. In the validation group, the proportions were similar (90%, 100%, 0%, and 0%, respectively) with an AUC-ROC of 0.96 (95% CI, 0.90-1.00; p<0.001). Conclusion : Our CTA-ABC score reliably assessed risk for sICH and/or MMCAI in patients with AIS who underwent EVT. It can support clinical decision-making, especially when the need for EVT is uncertain.

SNP Detection of Carboxypeptidase E Gene and Its Association with Meat Quality and Carcass Traits in Korean Cattle

  • Shin, S.C.;Chung, E.R.
    • Asian-Australasian Journal of Animal Sciences
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    • v.20 no.3
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    • pp.328-333
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    • 2007
  • Carboxypeptidase E (CPE) plays an important role in the regulation of the body fat content. Therefore, it has been suggested as candidate gene for traits related to meat quality in beef cattle. This study was conducted to identify single nucleotide polymorphisms (SNPs) in the CPE gene and to investigate association of SNP marker with carcass and meat quality traits in Korean cattle. Three SNPs were identified in the intron 4 (A309G SNP and C445T SNP) and exon 5 (C601T SNP) of the CPE gene by sequence analyses of CPE cDNA and genomic DNA samples. The sequences have been deposited in GenBank database with accession numbers AY970664 and AY970663. Genotyping of the gene-specific SNP marker was carried out using the PCR-RFLP with restriction enzymes DdeI for C445T SNP and NlaIII for C601T SNP. The frequencies of C and T alleles were 0.43 and 0.57 for C445T SNP and 0.42 and 0.58 for C601T SNP, respectively. Statistical analysis indicated that the C445T SNP showed a significant effect (p<0.05) on marbling score (MS) and breeding value of backfat thickness (BF-EBV), respectively. Animals with the CT genotype showed higher marbling score and backfat thickness than those with the TT genotype. This marker also showed a significant dominance effect for the MS and BF-EBV (p<0.05). However, no significant associations were observed between C601T SNP genotypes and all traits examined. The results suggest that the CPE gene may be used as a marker for carcass traits in Korean cattle.

Calculation of Dose Distribution for SBRT Patient Using Geant4 Simulation Code (Geant4 전산모사 코드를 이용한 SBRT 환자의 선량분포 계산)

  • Kang, Jeongku;Lee, Jeongok;Lee, Dong Joon
    • Progress in Medical Physics
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    • v.26 no.1
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    • pp.36-41
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    • 2015
  • The Monte Carlo based dose calculation program for stereotactic body radiotherapy was developed in this study. The Geant4 toolkit widely used in the radiotherapy was used for this study. The photon energy spectrum of the medical linac studied in the previous research was applied for the patient dose calculations. The geometry of the radiation fields defined by multi-leaf collimators were taken into account in the PrimaryGeneratorAction class of the Geant4 code. The total of 8 fields were demonstrated in the patient dose calculations, where rotation matrix as a function of gantry angle was used for the determination of the source positions. The DicomHandler class converted the binary file format of the DICOM data containing the matrix number, pixel size, endian type, HU number, bit size, padding value and high bits order to the ASCII file format. The patient phantom was constructed using the converted ASCII file. The EGSnrc code was used to compare the calculation efficiency of the material data.

The Effect of Specimen Thickness on the Fatigue Crack Propagation Rate (피로크랙전파율에 대한 시험편 두께의 영향)

  • Koh, Sung-Wi;Um, Yoon-Sung
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.24 no.1
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    • pp.44-49
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    • 1988
  • The paper presents the preliminary results of an esperimental study on crack growth under tension-tension fatigue loading. A purpose of the study is to find the effect of the specimen thickness on crack propagation behaviors. The thickness of the low catbon steel specimens the are used in the experiments are 5, 10, 15,20, and 25 mm. the type of specimen considering in the present study is compact tension specimen.Crack growth behaviors are obseved and measured by travelling microscope. From the study, the followings are found; 1. There is a certain specimen thickness that is the shortest farigue life. The fatigue life of 15mm specimen is the shorter then that of any other opecimen 2. The crack initiation of the thick specimen is slower than that of thin specimen. But the crack propagation rate is just the opposite. 3. The range which is the exponent, m of power law(paris) is 1.98-4.59. the thicker the spec-imen is, the higher the value of m is.

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The Value of Preoperative Multidetector Computed Tomography for Deep Inferior Epigastric Artery Perforator Free Flap (심하복벽동맥 천공지 유리피판에서 술전 MDCT의 유용성)

  • Heo, Chan Yeong;Hong, Ki Yong;Yoon, Chang Jin;Eun, Seok Chan;Baek, Rong Min;Minn, Kyung Won
    • Archives of Plastic Surgery
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    • v.36 no.2
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    • pp.140-146
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    • 2009
  • Purpose: Autologous breast reconstruction with abdominal tissue is one of the best options after mastectomy. In a free transverse rectus abdominis myocutaneous(TRAM) or deep inferior epigastric artery perforator(DIEP) flap, a preoperative evaluation of the precise location of perforating vessels and vascular run - off systems is required. The objective of this report is to demonstrate the usefulness of multidetector computed tomography(MDCT) in the preoperative planning of patients undergoing breast reconstruction with abdominal flap. Methods: From June 2006 to January 2008, 28 patients underwent MDCT evaluation before breast reconstruction. All subjects were females with an age range of 30 to 55 years. The CT scan was performed using a 64 - slice MDCT scanner(Brilliance 64; Philips Medical Systems, Best, Netherlands). Results: One perforator or two major perforators were marked on image in good relation with a hand - held Doppler examination and intraoperative findings. All vascular run - off systems were cleared before operation. Conclusion: Preoperative evaluation of perforator arteries with MDCT angiography is beneficial in patients undergoing breast reconstruction. This technique provides a noninvasive approach of the vascular anatomy of the entire anterior abdominal wall.

Internal Radiotherapy of Metastatic Hepatic Malignancy Using Colloidal P-32 in Various Gabtrointebtinal Tumors - The First Report: Prevention of Liver Metastasis Using Colloidal p-32 in Colo-Rectal Cancer- (각종(各種) 소화기암(消化器癌)에서 교질성(膠質性) 방사성(放射性) 인(燐)을 이용(利用)한 전이성(轉移性) 간암(肝癌의) 방사선(放射線) 내부치료(內部治療) -제1보(第1報) : 대장(大腸)-직장암(直腸癌)에서 교질성(膠質性) 인(燐)을 이용(利用)한 간전이(肝轉移)의 예방(豫防)-)

  • Kim, Ji-Yeul;Bom, Hee-Seung;Choi, Won;Kim, Young-Jin
    • The Korean Journal of Nuclear Medicine
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    • v.24 no.2
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    • pp.274-278
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    • 1990
  • Metastases to the liver presents a common clinical problem in the management of patients with cole-rectal cancer, and are responsible for a high degree of morbidity and mortality associated with this malignancy. Unfortunately, attempts at preventing the development of liver metastases in "high risk" patients has so far been unsuccessful. Ongoing studies of adjuvant chemotherapy have not yet illustrated a significant increase in survival in patients receiving such therapy. The purpose of the study is to investigate the value of adjuvant radiotherapy given in the form of colloidal chromic phosphate P-32 suspension administered via portal vein after radical resection of the primary cancer, in preventing the growth of occult metastases in the liver. Twenty one patients (10 patients of treated group with 11 controls) were followed 18 months after operation. There was no significant change in the CBC and liver functions after administration of P-32 labeled colloidal chromic phosphate. The number of patients who showed local metastases at 18 months were 2 in the treated group and 3 in the control group. While liver metastases occurred in one patient at 6 months and in three at 12 months in the control group, there was no development of liver metastases by 12 months in the treated group. At 18 month follow-up CT scan one patient in the treated group showed a single nodule in the liver. In conclusion liver metastasis rate was lower in the patients who received colloidal P-32 chromic phosphate via portal vein after radical resection of the primary cole-rectal cancer.

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Inhibitory Effects of Changchuldoin-tanggamibang on Collagen Induced Arthritis in DBA/1J Mouse (창출도인탕가미방(蒼朮桃仁湯加味方)이 DBA/1J 생쥐의 collagen 유발 관절염 억제에 미치는 영향)

  • Park, Jang-Woo;Oh, Min-Seok
    • The Journal of Korean Medicine
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    • v.31 no.2
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    • pp.19-35
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    • 2010
  • Objectives: This study was carried out to find the effects of Changchuldoin-tanggamibang (hereinafter referred to CDIT) on the inhibition of arthritis induced by collagen on DBA/1J mouse. Methods: The experimental mice were divided into four groups: normal group (Nr), control group (CIA-CT), methotrexate group (CIA-MTX), and Changchuldoin-tanggamibang group (CIA-CDIT). Cytotoxicity, hepatotoxicity, arthritis index, value of immunocytes in draining lymph node and paw joint, and rheumatoid factor (IgG, IgM) in serum were measured in vivo. Results: 1. Cytotoxicity against hFCs was not shown in any concentration. 2. Hepatotoxicity was low in the CDIT-treated group compared with the MTX group. 3. The arthritis index decreased significantly. 4. In total cell counts of DLN and paw joint, the cells in DLN increased significantly while there was a significant decrease in paw joint. 5. In lymph nodes, CD19+, CD3+, CD4+, CD8+, CD3+/CD8+, CD3+/CD69+, CD4+/CD25+, CD3+/CD49b+, and CD4+/CD44+ cells increased significantly, while B220+/CD23+, and CD11c+/MHCII+ cells decreased significantly. 6. In joints, CD3+, CD4+, CD4+/CD25+, and CD11b+/Gr-1+ cells decreased significantly. 7. The level of IgG decreased and the level of IgM significantly decreased compared with the control. 8. Anti-collagen II in serum decreased compared with the control. 9. Around the joint of the CDIT group, infiltration of inflammation, synovial hyperplasia, invasion of cytokine, of cartilage, deposition of collagen and synovial injury decreased compared with the control in histopathologic observation (HE, MT staining). Conclusions: Comparison of the results for this study showed that CDIT had immunomodulatory effects. We expect that CDIT could be used as a effective drug for not only rheumatoid arthritis but also another auto-immune diseases. Therefore, we have to survey continuously, looking for effective substances and mechanisms in the future.