• Journal of the Korea Concrete Institute
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• v.14 no.1
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• pp.126-135
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• 2002

Plate bonding technique has been widely used in strengthening of existing concrete structures, although it has often a serious problem of premature falure such as interface separation and rip-off. However, this premature failure problem has not been well explored yet especially in view of local failure mechanism around the interface of plate ends. The purpose of the present study is, therefore, to identify the local failure of strengthened plates and to derive a separation criterion at the interface of plates. To this end, a comprehensive experimental program has been set up. The double lap pull-out tests considering pure shear force and half beam tests considering combined flexure-shear force were performed. The main experimental parameters include plate thickness, adhesive thickness, and plate end arrangement. The strains along the longitudinal direction of steel plates have been measured and the shear stress were calculated from those measures strains. The effects of plate thickness, bonded length, and plate end treatment have been also clarified from the present test results. Nonlinear finite element analysis has been performed and compared with test results. The Interface properties are also modeled to present the separation failure behavior of strengthened members. The cracking patterns as well as maximum failure loads agree well with test data. The relation between maximum shear and normal stresses at the interface has been derived to propose a separation failure criterion of strengthened members. The present study allows more realistic analysis and design of externally strengthened flexural member with steel plates.

• Journal of Biomedical Engineering Research
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• v.19 no.4
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• pp.393-401
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• 1998

Based on clinical observations, it is suspected that the bone-tendon origin is the site where piratical failure, leading to pathophysiological changes in the humeral epicondyle after repetitive loading, is initiated Mechanical properties and failure patterns of the common extensor and flexor tendons of the humeral epicondyle under static and repetitive loading have not been well documented. Our goal was to determine mechanical properties of failure strength and strain changes, to correlate strain changes and the number of cyclic repetitions, and to identify the failure pattern of bone-tendon specimens of common extensor and flexor tendons of the humeral epicondyle. Mechnaical properties of human cadaver bone-tendon specimens of the common extensor and flexor tendons of the humeral epicondyle were tested under two different loading rates. No statistically significant difference in ultimate tensile strength was found between male and female specimens or between slow (10 mm/sec) and fast elongation (100 mm/sec) rates. However, a statistically significant difference in ultimate tensile strength between the common extensor (1190.0 N/$cm^2{\pm}$388.8) and flexor 1922.0 N/$cm^2{\pm}$764.4)tendons was found (p<0.05). When loads of 25%, 33%, and 41% of the ultimate tensile strength of their contralateral sides were applied, the number of cycles required to reach 24% strain change for the common extersor and flexor tendons were approximately 8,893, 1,907, and 410, respectively. The relationship between cycles and loads was correlated ($R^2$=0.46) Histological observation showed that complete or partial failure after tensile or cyclic loadings occurred at the transitional zone, which is the uncalcified fibrocartilage zone between tendon and bone of the humeral epicondyle. Sequential histological sections revealed that failure initiated at the upper, medial aspect of the extensor carpi radialis brevis tendon origin. Biomechanical and hstological data obtained in this study indicated that the uncalcified fibrocartilage zone at the bone-tendon origin of the common extensor and flexor tendons is the weak anatomical structure of the humeral epicondyle.

• Radiation Oncology Journal
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• v.22 no.2
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• pp.115-123
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• 2004

Purpose : This retrospective study was conducted to compare early preliminary results of breast conservation therapy (BCT) with mastectomy In early breast cancer. Materials and Methods : We evaluated 171 women with AJCC stage I and II breast cancer who had been treated at Kangnam St. Mary's Hospital from March 1989 to August 1996. Eighty-eight patients underwent mastectomy and 85 patients did conservative surgery with breast irradiation. in the BCT group, all patients received whole breast irradiation to a total dose of 45$\~$50 Gy/5$\~$6 wks, followed by a boost to the original tumor site at least 60 Gy. Chemotherapy was administered to 29 (34.1$\%$) patients in BCT and 40 (45.5$\%$) in mastectomy, with various sequencing of surgery and/or radiation. We compared survival rate, patterns of failure in each treatment group and the prognostic factors that had a significant effect on treatment failure. The median follow-up time was 63 months (19$\~$111 months). Log rank test was used to estimate the prognostic factors for treatment failure. Results : Overall survival, disease free survival, locoregional recurrence and distant metastasis rates were not significantly different between the two treatment groups. During the follow-up period, 11 patients (12.5$\%$)in the mastectomy group and 10 patients (11.8%$\%$ in the BCT group were failed. Six local recurrences occurred after mastectomy and 5 after BCT Five patients fatted at distant site in mastectomy and 4 in BCT. Of the local recurrence cases, five of 6 mastectomy patients and 3 of S BCT patients were alive with no evidence of disease after salvage surgery and/or chemoirradiation. Our results indicated that the major influence on survival was distant metastasis. Unfortunately, control of distant metastasisis was not frequently achieved. Even with salvage systemic therapy or radiotherapy, most of distant metastasis patients died or had uncontrolled disease in both treatment groups: only one of 4 BCT patients and none of mastectomy patients were alive without disease. There was no apparent difference in the incidence rate of contralateral breast cancer and non-breast 2$^{nd}$ primary tumor between the two treatment groups. Univariate Log-rank test identified the N stage and the involved axillary LN number as distinct prognostic factors that were highly predictive of treatment failure in both treatment groups. Additionally, marginal status in BCT and histologic nuclear grade In the mastectomy group were risk factors for treatment fallure (p < 0.05). Concousion : Although further careful follow-up is necessary to confirm the trends evident In this serles, it would appear that patterns of failure and survival rate following conservative surgery and radiotherapy in early breast cancer are similar to those following mastectomy. The great majority of patients with local recurrence had an exellent salvage rate in both treatment groups. Therefore, these preliminary short term results support BCT as an equally effective management for early breast cancer as an alternative to mastectomy.

• Radiation Oncology Journal
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• v.15 no.2
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• pp.129-136
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• 1997

Purpose : We analyzed the survival and failure patterns of cervix cancer patients treated with irradiation alone to evaluate our treatment method and to compare with the others Methods and Materials : Two hundred and twenty cervical cancer patients, Stage IB, II A, and II B who completed the planned treatment between Mar 1987 and December 1991 were analyzed retrospectively. The Stage IB patients were restaged to the Stage IB1 and IB2 by the recently revised FIGO classification, Patients were treated with a combination of external irradiation and the intracavitary brachytherapy Determination of the tumor control was done at the time of 6 months Postirradiation. The follow-up time was ranged from 3 to 115 months and the mean was 62 months and the follow-up rate was $93.6\%$(206/220) Results : The overall 5-year survival rate of Stage IB1 (N=50), IB2(N: 15). II A(N=58), and II B(N=97) was $94\%,\;87\%,\;69\%,\;and\;56\%$. respectively. In the univariate analysis of prognostic factors, stage(0.00), initial Hg level (P=0.00), initial TA-4(tumor-associated) antigen level(p= 0.02), initial CEA level(p=0.02), barrel-shaped tumor(p=0.02), whole cervical involvement (0.00), pelvic tyrnphadenopathy(LAP) in CT(p=0.04), and Post-irradiation adiuvant chemotherapy(P=0.00) were statistically significant in survival analysis. In a while multivariate analysis showed that the stage was the most powerful Prognostic indicator and the Post-irradiation chemotherapy factor also showed the statistical significance. The overall local control rate was $81\%$ and by the stage, $100\%$ in Stage IBI, $86.7\%$ in Stage IBS, $84.5\%$ in Stage IIA, and $68.1\%$ in Stage IIB, respectively The overall tumor recurrence rate was $15.5\%$(27/174) and by the stage, $8\%$(4/50) in Stage IB1, $0\%$(0/l3) in Stage IB2, $22.4\%$(l1/49) in Stage II A, and $19.4\%$(12/62) in Stage II B, respectively. Conclusions : We obtained the similar treatment results to the other's ones in early stage cervical cancer patients. But in Stage II B, the local control rate was lower than that of the other institutes and also the survival was poorer. So it seems to be necessary to reevaluate the treatment method in advanced cervical cancer patients.

• Radiation Oncology Journal
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• v.33 no.4
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• pp.284-293
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• 2015

Purpose: To determine failure patterns and survival outcomes of T4N0-1 non-small cell lung cancer (NSCLC) treated with definitive radiotherapy. Materials and Methods: Ninety-five patients with T4N0-1 NSCLC who received definitive radiotherapy with or without chemotherapy from May 2003 to October 2014 were retrospectively reviewed. The standard radiotherapy scheme was 66 Gy in 30 fractions. The main concurrent chemotherapy regimen was $50mg/m^2$ weekly paclitaxel combined with $20mg/m^2$ cisplatin or AUC 2 carboplatin. The primary outcome was overall survival (OS). Secondary outcomes were failure patterns and toxicities. Results: The median age was 64 years (range, 34 to 90 years). Eighty-eight percent of patients (n = 84) had an Eastern Cooperative Oncology Group performance status of 0-1, and 42% (n = 40) experienced pretreatment weight loss. Sixty percent of patients (n = 57) had no metastatic regional lymph nodes. The median radiation dose was EQD2 67.1 Gy (range, 56.9 to 83.3 Gy). Seventy-one patients (75%) were treated with concurrent chemotherapy; of these, 13 were also administered neoadjuvant chemotherapy. At a median follow-up of 21 months (range, 1 to 102 months), 3-year OS was 44%. The 3-year cumulative incidences of local recurrence and distant recurrence were 48.8% and 36.3%, respectively. Pretreatment weight loss and combined chemotherapy were significant factors for OS. Acute esophagitis over grade 3 occurred in three patients and grade 3 chronic esophagitis occurred in one patient. There was no grade 3-4 radiation pneumonitis. Conclusion: Definitive radiotherapy for T4N0-1 NSCLC results in favorable survival with acceptable toxicity rates. Local recurrence is the major recurrence pattern. Intensity modulated radiotherapy and radio-sensitizing agents would be needed to improve local tumor control.

• The korean journal of orthodontics
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• v.28 no.5 s.70
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• pp.783-789
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• 1998

The purpose of this study was to evaluate the changes of shear bond strengths and failure patterns in orthodontic resin adhesives according to the water immersion time. Metal brackets were bonded to the specimens involving the premolars with chemical-cured($Concise^{\circledR}$) and light-cured($Transbond^{\circledR}$) adhesives. The shear bond strength was measured on universal testing machine and the failure patterns were assessed with the adhesive remnant index(ARI) after storage in distilled water at $37^{\circ}C$ for 1 day, 1 week and 1, 3, and 6 months, respectively. The results were as follows. 1. The shear bond strengths at the 6 month in both Concise and Transbond were significantly higher than those at the 1 day, 1 week and 1 month(p<0.05). There were positive correlations between shear bond strength and water immersion time in both Concise and Transbond(P<0.01). 2. There were no significant differences in shear bond strength between Concise and Transbond. 3. The brackets were failed primarily at the bracket base-adhesive interface and there was no significant difference in the incidence of ARI scores according to the water immersion time.

• Korean Journal of Clinical Pharmacy
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• v.21 no.2
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• pp.170-181
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• 2011

Purpose: There is considerable variability in rates of hospitalization for patients with community-acquired pneumonia (CAP) in part because of physicians' uncertainty in assessing the severity of illness at presentation. The purpose of the study was to examine the current treatment patterns and factors influencing the Pneumonia Severity Index (PSI) and clinical outcomes in the patient with CAP. Method: The retrospective data collection of the patients with CAP was conducted and the data were reviewed. The collected data included demographic, clinical, laboratory and microbiological medical information. All patients were stratified into three risk groups according to PSI: low risk (PSI score I-II), moderate risk (III) and high risk (IV-V) groups. The examined treatment patterns were the appropriateness of admissions, category of antibiotics used. The prognostic factors associated with PSI and clinical outcomes were examined. Results: One hundred and six patients' medical data were reviewed. The overall appropriateness of admissions was low presenting many of patients were admitted or intensely treated in the hospital despite of lower risk of prognosis and treated with intravenous antibiotics instead of oral fluoroquinolones. Primary pneumonia pathogens were Klebsiella pneumoniae (27%) and Streptococcus pneumoniae (21.6%). Mean LOS was 8.5 days and was significantly longer (10.0days) (p<0.001) in high risk group. The patients with age >65 (p<0.001), diabetes mellitus (p<0.001), mental alteration (p<0.001), and/or $PaO_2$ <60 mmHg (p<0.001) had a tendency to have higher PSI. The prognostic factors associated with longer LOS were age >65 years (p=0.008), mental status alteration (p<0.001), dyspnea (p=0.002) and PSI score (p=0.001). The prognostic factors associated with mortality were congestive heart failure (p=0.038), systolic blood pressure <90 mmHg (p=0.002) and arterial pH <7.35 (p=0.013). Conclusion: Most of patients were found to over-utilize medical service according to appropriateness of admissions. The elderly, mentally altered patients with low $PaO_2$ had higher PSI score with increased risk of LOS. The mortality could be increased in the patient with disease state of congestive heart failure, high blood pressure, and/or acidosis.

• The korean journal of orthodontics
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• v.28 no.4 s.69
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• pp.659-668
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• 1998

The purpose of this study was to evaluate the possibility of the decrease of bond strength due to increased thickness of resin base in indirect bracket bonding technique. Metal brackets were bonded to the resin blocks involving bovine lower incisors and the thickness of resin bases was increased by increments of 0.5 mm from 0.0 mm to 2.0 mm. They were divided into two groups, one group is that the thickness of resin base was increased but the loading point from the tooth surface was maintained constantly, the other group is that the loading point from the tooth surface and the resin base thickness were increased concomitantly. The shear bond strength was tested on universal testing machine and the failure patterns were assessed with the adhesive remnant index(ARI). The results were as follows: 1. When the distance from the tooth surface to the loading point was maintained constantly, shear bond strength was increased significantly according to the decrease of distance from the bracket base to the loading point and the increase of resin base thickness. 2. When the distance from the tooth surface to the loading point and the resin base thickness were increased concomitantly, shear bond strength was decreased according to the increase of resin base thickness but significant differences were ignorable. 3. There were no significant differences in ARI scores according to the change in the thickness of resin base. The results of the present study indicated that shear bond strength was not much affected by the thickness of resin base, whereas was decreased according to the increase of distance from bracket base to the loading point.

• The korean journal of orthodontics
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• v.28 no.2 s.67
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• pp.277-284
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• 1998

The purpose of this study was to evaluate the propriety of making use of the light-cured resin base in indirect bracket bonding technique by study of shear bond strength and failure patterns according to the material of resin base. Metal brackets were bonded to the stone models of specimens involving bovine lower incisor with chemical-cured(Excel), light-cured(Light-Bond) and thermal-cured(Therma-Cure) resin. They were transferred to the specimens and bonded using sealant. The shear bond strength was tested on Instron. After bracket removal, the bracket base was examined and assessed with the adhesive remnant index(ARI). The results were as follows : 1. No significant differences in shear bond strength were found among the three groups (P>0.05). 2. No significant differences in ARI score were found among the three groups (P>0.05). The above results suggest that light-cured resin base in addition to chemical-cured and thermal-cured resin bases is useful in the indirect bonding technique.

• The Journal of Korean Society of Virology
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• v.29 no.1
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• pp.11-22
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• 1999

Sero-epidemiologic survey has been carried out to establish serologically the presence of hantavirus in areas of South Africa. The survey was oriented to search natural infection in both of humans and wild rodents and involvement of human disease. The normal human sera were collected from the residents in urban and rural areas of Western Cape, and rural area of Eastern Cape province. The rodent sera came from various species of rodents trapped in Northern Cape and Western Free provinces. The patient sera were selected from the patients of renal failure, pulmonary syndrome and pyrexia of unknown origin (PUQ) according to diagnostic chart among the patients hospitalized in major hospitals of Cape Town area. The sera were screened and titrated by IFA test using antigens of Hantaan (HTN), Seoul (SEO), Puumala (PUU), and Prospect Hill (PH) viruses primarily. Positive cases were subjected to differential IFA test using HTN, PUU and PH antigens and plaque reduction neutralization test for further confirmation. Anti-hantavirus antibodies were detected from 2 of 352 rural, 1 of 172 urban residents of E. Cape, and 5 of 118 rural, 5 of 368 urban residents of W. Cape. The antibody was also demonstrated from 5 of 221 wild rodents, and it was appeared that 2 different species, Aethomys namaquensis and Tatem leucogaster, are involved. Among 318 patients tested, 3 who were diagnosed as chronic renal failure, acute respiratory distress syndrome (ARDS) and glomerulonephritis were proved to be positive. The reaction patterns obtained from all of these positive sera were distinct from hantaviral sero-patterns ever established. This result suggests that new viruses may exist in this area and play an possible etiologic role in human disease. The feature of serologic survey on anti-hantavirus antibody demonstrable newly from African wild rodents which are different from reservoir species in other continents elicits a conjecture that the virus may be different from known hantaviruses ever found. This fact also suggests that an expanded role in etiologic involvement with other unknown human diseases by newly emerging hantaviruses may be possible in this areas.