• Membrane and Water Treatment
• /
• v.8 no.2
• /
• pp.137-147
• /
• 2017

A water treatment utility in South Korea operates a large system of pressurized hollow fiber membrane (PHFM) modules. The optimal selection of membrane module for the full scale plant was critical issue and carried out using Risk-based Life Cycle Cost (RbLCC) analysis based on the historical data of operation and maintenance. The RbLCC analysis was used in the process of decision-making for replacing aged modules. The initial purchasing cost and the value at risk during operation were considered together. The failure of modules occurs stochastically depending on the physical deterioration with usage over time. The life span of module was used as a factor for the failure of Poisson's probability model, which was used to obtain the probability of failure during the operation. The RbLCC was calculated by combining the initial cost and the value at risk without its warranty term. Additionally, the properties of membrane were considered to select the optimum product. Results showed that the module's life span in the system was ten years (120 month) with safety factor. The optimum product was selected from six candidates membrane for a full scale water treatment facility. This method could be used to make the optimum and rational decision for the operation of membrane water purification facility.

• The Korean journal of internal medicine
• /
• v.33 no.6
• /
• pp.1039-1049
• /
• 2018

The populations of Asian countries are expected to age rapidly in the near future, with a dramatic increase in the number of heart failure (HF) patients also anticipated. The need for palliative and end-of-life care for elderly patients with advanced HF is currently recognized in aging societies. However, palliative care and active treatment for HF are not mutually exclusive, and palliative care should be provided to reduce suffering occurring at any stage of symptomatic HF after the point of diagnosis. HF patients are at high risk of sudden cardiac death from the early stages of the disease onwards. The decision of whether to perform cardiopulmonary resuscitation in the event of an emergency is challenging, especially in elderly HF patients, because of the difficulty in accurately predicting the prognosis of the condition. Furthermore, advanced HF patients are often fitted with a device, and device deactivation at the end of life is a complicated process. Treatment strategies should thus be discussed by multi-disciplinary teams, including palliative experts, and should consider patient directives to address the problems discussed above. Open communication with the HF patient regarding the expected prognosis, course, and treatment options will serve to support the patient and aid in future planning.

• Journal of radiological science and technology
• /
• v.45 no.5
• /
• pp.439-448
• /
• 2022

The purpose of this study was to analyze the results from statistical process control (SPC) to recommend upper and lower control limits for planning parameters based on delivery quality assurance (DQA) results and establish our institutional guidelines regarding planning parameters for helical tomotherapy (HT). A total of 53 brain, 41 head and neck (H & N), and 51 pelvis cases who had passing or failing DQA measurements were selected. The absolute point dose difference (DD) and the global gamma passing rate (GPR) for all patients were analyzed. Control charts were used to evaluate upper and lower control limits (UCL and LCL) for all assessed treatment planning parameters. Treatment planning parameters were analyzed to provide its range for DQA pass cases. We confirmed that the probability of DQA failure was higher when the proportion of leaf open time (LOT) below 100 ms was greater than 30%. LOT and gantry period (GP) were significant predictor for DQA failure using the SPC method. We investigated the availability of the SPC statistic method to establish the local planning guideline based on DQA results for HT system. The guideline of each planning parameter in HT may assist in the prediction of DQA failure using the SPC statistic method in the future.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.29 no.2
• /
• pp.102-107
• /
• 2003

At orthodontic treatment, we have made every effort to get rigid anchorage which is not stirred when teeth move. As a result, the miniscrew that is rigid anchorage was invented recently, and now it is used widely. Concerning the advantage of miniscrew, it is reduced dependence of extraoral anchorage and it shortens treatment time for rapid tooth movement. In contrast, the defect of miniscrew is falling off it resulted from increasing of the mobility. So the purpose of this research is to be of help to prognose clinical use of miniscrew, which is inserted for intraoral anchorage, by investigating and comparing the failure rate of miniscrew for loading time. This study researches the failure rate of miniscrew for teeth movement at the orthodontic treatment. The failure rate of miniscrew in mid course, after inserting 147 miniscrews in 51 patients, is 13%(20/147). It showed no statistically significant differences as compared man with woman, maxilla with mandible, double-head with uni-head miniscrew, and drilling and non-drilling before inserting the miniscrew. In comparison below twenties with over twenties and the times that we give load to miniscrew, it produced that the failure rate of miniscrew is 9.7% higher in the case of below the twenties than over the twenties. Also, the failure rate of loading immediately is 10.8% higher than loading after 7 days. According to using driver for the insertion of miniscrew, the failure rate of miniscrew is higher in the case of using machined driver than in the case of using hand driver when the level of significance is 95%. According to the research, we can suppose that the failure rate has no concern with using miniscrew on man or woman, maxilla or mandible, the shape of head, and drilling or non-drilling before insertion of miniscrew. Therefore, we can choose eclectic miniscrew as demands. In addition, we must notify the patient, below twenties, to be possibility of high failure rate. And It is strongly recommended to give load after $1{\sim}2$ weeks for healing of the insertion area.

• Radiation Oncology Journal
• /
• v.9 no.1
• /
• pp.73-79
• /
• 1991

Between January 1980 and September 1988,08 patients with advanced T3 & T4 glottic carcinoma were treated with RT and surgery/RT in the Department of Radiation Oncology, Yonsei Cancer Center and ENT, Yonsei University College of Medicine. The mean age was 60 years old (range 33 to 79 years old). The 34 patients were treated with irradiation alone, and the remaining 34 patients with surgery and irradiation. Initial nodal presentation was $37\% (25/68);\;31\%$ (l1/34) in RT alone group and $41\%$ (14/34) in combined treatment group. The minimum follow-up was 2 years. The local control rate after treatment was $47\%$ in RT alone group and $65\%$ in combined treatment group; $57\%$ for node negative and $27\%$ for node positive patients treated with RT alone; $65\%$ for node negative and $54\%$ for node positive patients treated with combined treatment. The treatment failure was observed in 30 patients; 14 patients for primary local failure, 6 patients for regional nodal failure,5 patients for local and regional failure, 26 patients for primary failure and/or distant metastasis, and 2 patient for regional failure and/or distant metastasis. The overall 5-year suwival rate was $57\%;\;37\%$ in RT alone group and $70\%$ in combined treatment group; $55\%$ for node negative and $20\%$ for node positive patients treated with RT alone; $73\%$ for node negative and $77\%$ for node positive patients treated with combined treatment. In conclusion, the combined treatment groups in the treatment of advanced 73 and 74 glottic cancer showed the better results in local control rates and S-year actuarial survival rates than RT alone group. We suggest that total laryngectomy and postoperative RT in the most patients of advanced glottic cancer were performed. However, in cases of node negative patints, RT alone is prefer as a treatment modality over combined surgery and RT since the treatment results were comparable and furthermore functional preservation could be achieved.

• The Journal of Internal Korean Medicine
• /
• v.24 no.4_2
• /
• pp.1046-1054
• /
• 2003

Renal Failure is called a disorder of kidney excretion induced by glomerulus filtration rate(GFR) decrease. GFR is measured by Blood Urea Nitrogen(BUN) and Cretinine in blood. This study is about Oriental diagnosis and treatment of Chronic renal failure(CRF) patients. We treated five cases which were diagnosed as CRF by using methods used in oriental medicine, the application of Youkmijihwang-tang(六味地黃湯加減). In most such cases, we concluded that the results turns better as the symptoms like fatigue and digestive disorder decreases and the decrease of BUN and Creatinine in blood as well.

• Journal of The Korean Society of Clinical Toxicology
• /
• v.2 no.1
• /
• pp.45-48
• /
• 2004

Paraquat, a widely used herbicide, is extremely toxic, causing multiple organ failure in human. Many treatment modality has been used, but now paraquat is very fatal drug. Elimination rate of plasma paraquat seems to be a factor for the survival rate. So early diagnosis and early treatment are very important. Plasma paraquat concentration could be measured by radioimmunoassay. But it is impossible that the test was done at Emergency room and the result was checked immediately. There was relation between plasma paraquat concentrations and urine paraquat concentration. Because of its simplicity and low cost, urine paraquat concentration test is complementary to the plasma concentration measurement. If the patient has psychotic problem or unconscious mental state, and is observed unexplained dyspnea and oral ulcer, urine paraquat test is very important to rule out acute paraquat intoxication. We experienced a patient who was presented as unexplained acute renal failure initially and was diagnosed as paraquat intoxication later.

• The Journal of Korean Academy of Prosthodontics
• /
• v.39 no.2
• /
• pp.157-170
• /
• 2001

The bond strength is the most important factor in establishing long-term success of resin-retained fixed prostheses. So, various surface treatment methods have been introduced to improve the bond strength of metal surface and bonding resin till now This study was performed to compare the effect of silicoating with that of metal primer and analyze the correlation between treatment time of sandblasting and the bond strength, so that meant to find more effective surface treatment method that could enhance the bond strength of resin-retained fixed prostheses. The surfaces of all specimens made of $Verabond^{(R)}$ alloys were air abraded with $250{\mu}m\;Al_2O_3$ according to treatment time of sandblasting and they were subdivided to be treated with only sandblasting(S group), silicoating following sandblasting(SS group) and metal primer application after sandblasting(SM group). Then pairs of metal specimens (${\phi}10mm{\times}h\;2mm,\;{\phi}6{\times}h\;2mm$) were bonded with Super bond $C&B^{(R)}$. The specimens were stored in $38^{\circ}C$ water for 48 hours and shear bond strength was measured using the universal testing machine. The results were as follows, 1. In the comparison of shear bond strength according to treatment time of sandblasting, bond strength was increased in the order of 0', 15', 30', 45', 60' group. 0' group had significantly lower value than any other, while 0', 15' group were significantly different with 30', 45', 60' group(p<0.05). 2. In the comparison of shear bond strength according surface treatment methods, bond strength was increased in the order of S group. SS group and SM group. S group was significantly different with SS group and SM group(p<0.05). 3. Observing the mode of bond failure. 0', 15' group showed only adhesive failure, and 30', 45', 60' group did mostly adhesive & cohesive failure in S group. In SS group and SM group, all other groups except 0', 15' group showed mostly cohesive failure. From the above results, it is considered that sandblasting should be treated for more than 30 seconds, and metal primer be more effective and available clinically than silicoater system which is complicate, technique-sensitive and time-consuming method, when nonprecious metal surface is planning be treated with in order enhance the bond strength of resin-retained fixed prostheses.

• Tuberculosis and Respiratory Diseases
• /
• v.43 no.6
• /
• pp.862-870
• /
• 1996

Background : Multidrug-resistant tuberculosis(MDR-Tb) has been increased not only in Asia but also in Western society, which may cause public health problems and reduce the efficacy of treatment of tuberculosis. In Western society HIV infection is believed to do a central role in increasing incidence of MDR tuberculosis, but MDR-Tb in Korea may be somewhat different about clinical features, underlying disorders, and prognosis. Goble et al reponed that overall treatment failure rate in MDR-Tb including resistance to isoniazid(INH) and rifampin (RFP) was 44 %. The aim of this study is to find the treatment result in Korea and the factors determining the prognosis. Methods: A retrospective study of pulmonary tuberculosis cultured M. tuberculosis from sputum or bronchial washing fluid between 1986 through 1992 was conducted in the Seoul Paik Hospital, Inje University. We reviewed clinical courses of 141 patients, who had a tuberculosis with resistance to 2 or more drugs including isoniazid(INH) and rifampin(RFP). One hundred and 4 patients of 141 patients had completed treatment and followed up for more than one year. Results: Of 104 (mean age $43.6{\pm}16.7$, M: F=63 : 41) patients with sufficient follow-up data, 73(84.6%) patients responded which is defined as negative Sputum cultures for at least 3 consecutive months. Seven patients(6.7%) had a failure in negative conversion and 9(8.7%) of the patients who initially responded relapsed. Overall treatment failure rate was 15.4%, Patients who were treated for less than 12 months had a higher relapse rate(12.3%) than 18 months(4.9%). And there was a statistically significant correlation between the relapse rate and the number of drugs to which isolates wera resistant(p<0.05). Conclusion : The treatment failure rate of MDR-Tb in Korea was lower than previous studies in western Country and the major determining factor of prognosis was the number of resistant drugs to M. tuberculosis at drug sensitivity test. For reducing the relapse rate, we recommend more than 12 months of treatment for MDR tuberculosis.

• Restorative Dentistry and Endodontics
• /
• v.26 no.2
• /
• pp.171-179
• /
• 2001

The purpose of this study was to evaluate the shear bond strength of compomers according to dentin surface treatment. Two materials of compomer were devided into six groups. The compomer used in this study were Dyract AP(D) and F2000(F), Group 1 (DN) and 4(FN) were treated according to manufacturers instructions as control groups. Group 2(DE) and 5(FE) were treated with 37％ phosphoric acid and group 3(DA) and 6(FA) were treated with air abrasion unit (80 psi, 50 m aluminum oxide particles) respectively as experimental groups. After dentin surface treatment, compomers were bonded. Completed samples were stored in 100％ humidity. 37C during 7 days, and then, the shear bond strength of specimens were evaluated. The results were as follows: 1. In the case of Dyract AP, the shear bond strength was showed the highest value of 9.10 MPa in dentin surface treatment with air abrasion unit. but there were no significant differences to the other groups. 2. In the case of F2000. the shear bond strength was showed the highest value of 13.51MPa and there were significant differences to the other groups(p<0.05). 3. The shear bond strength of F2000 was higher than Dyract AP in each dentin surface treatment. and in the case of etching and air abrasion. there were significant differences(p<0.05). 4. As a result of observation of SEM. the most of fracture pattern was adhesive failure in group 1(DN), 2(DE) and 4(FN), and cohesive failure in group 3(DA), S(FE) and 6(FA).