• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.1
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• pp.1-8
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• 2011

Introduction: The utility of the C-terminal cross-linking telopeptide test (CTX) as a method for staging Bisphosphonate-related osteonecrosis of the jaws (BRONJ) and its healing process was examined. Materials and Methods: A total 19 patients who were diagnosed with BRONJ underwent a fasted morning CTX test, were enrolled in this study. The serum CTX values ranged from 50 to 630 pg/mL (mean 60). The risk assessment was rated according to the CTX values of the individual patient (minimal risk, ${\geq}$ 150 pg/mL, moderate, 100 to 150 pg/mL, high, ${\leq}$100 pg/mL). The BRONJ scores were then calculated according to the number of BRONJ lesions and their stage. The operation was done as soon as possible, regardless of BORNJ stage. Results: The mean duration of bisphosphonate therapy was 4.1 years. Of the 19 patients, 15, 2 ans 2 received alendronate, risedronate and zoledronate, respecively. Of the 19 patients who underwent a sequestrectomy, saucerization and smoothing, 15 healed after the initial surgery, 1 patient healed after one more surgical procedure, 3 patients did not heal completely but showed improvement in symptoms. Therefore, 17 out of the 19 patients healed completely with complete mucosal coverage and the elimination of pain. The risk assessment using the CTX value and disease severity were not correlated (r=-0.264, P=0.275). In addition, the risk assessment using CTX value and healing after surgery were not correlated (r=-0.147, P=0.547). Conclusion: The serum CTX should be considered carefully by clinicians as part of overall management. Early surgical intervention is of benefit in the treatment of stage II BRONJ.

• Clinical and Experimental Pediatrics
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• v.53 no.11
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• pp.957-964
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• 2010

Purpose: Our study attempted to determine the prognostic significance of minimal residual disease (MRD) detected by a simplified flow cytometric assay during induction chemotherapy in children with B-cell acute lymphoblastic leukemia (B-ALL). Methods: A total of 98 patients were newly diagnosed with precursor B-ALL from June 2004 to December 2008 at the Asan Medical Center (Seoul, Korea). Of those, 37 were eligible for flow cytometric MRD study analysis on day 14 of their induction treatment. The flow cytometric MRD assay was based on the expression intensity of CD19/CD10/CD34 or aberrant expression of myeloid antigens by bone marrow nucleated cells. Results: Thirty-five patients (94.6%) had CD19-positive leukemic cells that also expressed CD10 and/or CD34, and 18 (48.6%) had leukemic cells with aberrant expression of myeloid antigens. Seven patients with ${\geq}1%$ leukemic cells on day 14 had a significantly lower relapse-free survival (RFS) compared to the 30 patients with lower levels (42.9 % [18.7%] vs. 92.0% [5.4%], $P$=0.004). Stratification into 3 MRD groups (${\geq}1%$, 0.1-1%, and <0.1%) also showed a statistically significant difference in RFS (42.9% [18.7%] vs. 86.9% [8.7%] vs. 100%, $P$=0.013). However, the MRD status had no significant influence on overall survival. Multivariate analysis demonstrated that the MRD level on day 14 was an independent prognostic factor with borderline significance. Conclusion: An MRD assay using simplified flow cytometry during induction chemotherapy may help to identify patients with B-ALL who have an excellent outcome and patients who are at higher risk for relapse.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.11
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• pp.4727-4732
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• 2014

Background: Breast cancers are becoming more frequently diagnosed at early stages with improved long term outcomes. Late normal tissue complications induced by radiotherapy must be avoided with new breast radiotherapy techniques being developed. The aim of the study was to compare dosimetric parameters of planning target volume (PTV) and organs at risk between conformal (CRT) and intensity-modulated radiation therapy (IMRT) after breast-conserving surgery. Materials and Methods: A total of 20 patients with early stage left breast cancer received adjuvant radiotherapy after conservative surgery, 10 by 3D-CRT and 10 by IMRT, with a dose of 50 Gy in 25 sessions. Plans were compared according to dose-volume histogram analyses in terms of PTV homogeneity and conformity indices as well as organs at risk dose and volume parameters. Results: The HI and CI of PTV showed no difference between 3D-CRT and IMRT, V95 gave 9.8% coverage for 3D-CRT versus 99% for IMRT, V107 volumes were recorded 11% and 1.3%, respectively. Tangential beam IMRT increased volume of ipsilateral lung V5 average of 90%, ipsilateral V20 lung volume was 13%, 19% with IMRT and 3D-CRT respectively. Patients treated with IMRT, heart volume encompassed by 60% isodose (30 Gy) reduced by average 42% (4% versus 7% with 3D-CRT), mean heart dose by average 35% (495cGy versus 1400 cGy with 3D-CRT). In IMRT minimal heart dose average is 356 cGy versus 90cGy in 3D-CRT. Conclusions: IMRT reduces irradiated volumes of heart and ipsilateral lung in high-dose areas but increases irradiated volumes in low-dose areas in breast cancer patients treated on the left side.

• Fire Science and Engineering
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• v.18 no.3
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• pp.57-73
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• 2004

Quantitative safety analysis through a fault tree method has been conducted for a fire broken out over the spilling LNG from a pilot LNG tank, which may have 4 types of scenarios causing potentially risky results. When we consider LNG release from venting pipelines as a first event, any specific radius of Low Flammable Limit(LFL) has not been built up. The second case of LNG outflow from the rupture of storage tank which will be the severest has been analyzed and the results revealed various diffusion areas to the leaking times even with the same amount of LNG release. As a third case LNG leakage from the inlet/outlet pipelines was taken into consider. The results showed no significant differences of LFL radii between the two spilling times of 10 and 60 minutes. Hence, we have known the most affecting factor on the third scenario is an initial amount of LNG release. Finally, the extent of LFL was calculated when LNG pipelines around the dike area were damaged. In addition, consequence analysis has been also performed to acquire the heat radiation and flame magnitude for each case.

• Journal of Chest Surgery
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• v.25 no.12
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• pp.1404-1415
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• 1992

To understand the factors influencing Atrial fibrillation and embolism in mitral valve surgery and prevent their risk, we have reviewed our 324 patients who underwent mitral valve surgery from Fev. 1982 to May 1992. Age, disease duration, lesion type, left ventricular function and left atrial dimension were chosen as preoperative factors influencing the incidence of atrial fibrillation and embolism and their postoperative course, The number and type of replaced valve, site of atriotmy, LA obliteration, ACT and use of Defibrillator were chaser. as operative factors influencing postoperative rhythm change and postop emb-olization. The results of analyses were as follows 1. The incidence of preoperative atrial fibrillation, systemic embolism and LA throbmus was 63. 6%, 10.56% and 19.8% relatively. 2. The preoperative factors of atrial fibrillation onset was old age, prolonged symptom duration, stenotic lesion, lager LAD and lower ejection fraction. In the preoperative systemic embolism preoperative factors were old age, female, stenotic lesion. The left atrial thrombus found more commonly in patients with atrial fibrillation, old age, prolonged symptom duration, stenotic lesion and low ejection fraction. 3. The preoperative atrial fibriation persisted postoperatively in 165[50.9%] and converted to normal sinus rhythm in 50[15.4%]. The preoperative normal sinus rhythm per-eisted in 100[31%] and atrial fibrillation was occured postoperatively in 9[2.7%]. The prolonged symptom duration was the preoperative factor of persist atrial fibrillation. 4. Among 95 long term follow-up patients, atiral fibrillation was continued in 59[60%]. Conversion to normal sinus rhythm was more common significantly in left atriotomy and bileaflet valve replacement. 5. There were 12 patients who had postoperative embolism. Female, persist atrial fibrillation, no LA olbiteration and tilting disc monocusp valve were considered as possible factors influencing postoperative embolism but was impossible to analyse their statistical significance due to small sample size. So we have concluded that the patients with above risk factors need anticoagulant and early surgical intervention. Left atriotomy with minimal atrial injury, left auricular obliteration and bileaflet valve replacement may be needed to reduce postoperative atrial fibrillation persist and embolism.

• Journal of Chest Surgery
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• v.29 no.6
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• pp.646-650
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• 1996

The usual methods for the re-attachment of coronary ostia to the ascending aortic conduit have several disadvantages and potential complications. A novel, straight forward technique is described that allows for tension free anastomoses to be co structed with minimal risk of blood loss and a reduced risk of reoperation for false aneurysms at the anastomoses. We performed this technique for the treatment of a 40-yrs-old male patient of acute aortic dissection (Stanford Type A, DeBakey Type I) with severe aortic re- gurgitation. The techinque comprised anastomosis of a beveled interposition tube graft to the left main coronary artery ostium, and its proximal anastomosis to the ascending aortic graft after seating the com- posite valve graft in the prepared aortic annulus. With this technique, the low-Iying or distant left main coronary ostium can be easily reattached to the ascending conduit without undue tension.

• Environmental Analysis Health and Toxicology
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• v.11 no.1_2
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• pp.1-10
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• 1996

A decrease in stratospheric ozone probably caused by chloroflurocarbons (CFCs) emissions, has been observed large parts of-the globe. It is generally accepted that if ozone levels in the stratosphere are depleted, greater amounts of shortwave ultraviolet radiationB (UVB) will reach the earth's surface, resulting in increased incidence of nonmelanoma skin cancer. In this study, we evaluated several mathematical models, such as a power and an exponential model, and a geometric model considering the surface area of a human body part and ages for the prediction of Skin cancer incidence caused by exposure to the UVB radiation. These models basically estimated the risk of skin cancer based on those measurements of the local ozone in stratosphere and UVB. Both were measured at a part of Seoul with a Dobson ozone spectrometer and Robertson-Berger UV Biometer for 1995. As a result, we calculated the point estimation applying a biological amplification factor (BAF), UVB radiation and other factors. We used a Monte-Carlo simulation technique with assumption on the distribution of each considered factor. The sensitivity analysis of model by there components conducted using Gaussian sensitivity method. The annual integral of UVB radiation was 2275 MED (minimal erythema dose)/yr. Also, an estimate of the annual amount of UVB reaching the earth's surface at a korea's latitude and altitude was 3328 MED/yr. The values of the radiation amplification factor (RAF) were ranged from 0.9 to 1.5 in Seoul. To give the effective factors required to model the prediction of skin cancer incidence caused by exposure to the UVB radiation in Korea, we studied the pros and cons of above mentioned models with the application of those parameters measured in Seoul, Korea.

• Journal of the Korean Institute of Gas
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• v.19 no.4
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• pp.49-54
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• 2015

The purpose of this study is to assess the risk of depending on the presence or absence of safety device of domestic heating and drying furnaces, by derivation and analysis of accident frequency of safety devices through FTA (Fault Tree Analysis). Installation standards are lacking in Korean for the safety device of LPG heating and drying furnace, which have a risk of explosion due to structure to trap the leaked gas. Four different safety devices were selected on the basis of NFPA and national standards for combustors of other equipment. Effects of frequency reduction in accidents were analyzed before and after installing the safety devices respectively. As a result, a minimal leakage safety device was presented for preventing damages from gas leak of domestic LPG heating and drying furnace.

• Journal of Convergence for Information Technology
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• v.11 no.4
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• pp.230-241
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• 2021

This study has attempted to provide an important understanding about the information asymmetry in markets through empirical analysis on how the disclosure of low quality can increase demand even in the short run. More specifically, this study has extended the previous findings from the related literature by considering the effect of information search cost and providing empirical evidences about the effect of voluntary disclosure of low quality, using an experimental method with purchase scenarios. The results from our analysis show that reduced perceived risk have an important effect on sharing negative information, while the effect of information search cost is minimal. We also explain the circumstances whereby the information disclosure of a seller with low-quality product can enhance not only the seller's profitability but also customers' welfare by increasing the market demand and the demand for the seller claiming high quality.

• Safety and Health at Work
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• v.12 no.2
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• pp.244-248
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• 2021

Background: Sunburn is the main avoidable cause of skin cancer. Beach lifeguards spend many hours exposed to the effects of solar radiation during their work day, precisely at times of the year when levels of solar irradiation are highest. The aim of this study is to quantify the risk to beach lifeguards of sun exposure. Methods: A descriptive cross-sectional study was carried out in the Western Costa del Sol, southern Spain, during the summer of 2018. The research subjects were recruited during a skin cancer prevention course for beach lifeguards. All participants were invited to complete a questionnaire on their habits, attitudes, and knowledge related to sun exposure. In addition, ten were specially monitored using personal dosimeters for three consecutive days, and the results were recorded in a photoprotection diary. A descriptive analysis (mean and standard deviation for the quantitative variables) was performed, and inter-group differences were evaluated using the Mann-Whitney U test. Results: Two hundred fifteen lifeguards completed the questionnaire, and 109 met the criteria for inclusion in this analysis. The mean age was 23.8 years (SD: 5.1), 78.0% were male, 71.5% were phototype III or IV (Fitzpatrick's phototype), and 77.1% had experienced at least one painful sunburn during the previous summer. The mean daily personal ultraviolet exposure per day, the minimal erythema dose, and the standard erythema dose, in J/m², were 634.7 [standard deviation (SD): 356.2], 2.5 (SD: 1.4) and 6.35 (SD: 3.6), respectively. Conclusion: Beach lifeguards receive very high doses of solar radiation during the work day and experience correspondingly high rates of sunburn. Intervention strategies to modify their sun exposure behavior and working environment are necessary to reduce the risk of skin cancer for these workers and to promote early diagnosis of the disease.