Yttrium-Stabilized Zirconia Particles Prepared Using Electro-dialysis of (Zr,Y)OCl2 Aqueous Solution

장명철 한국세라믹학회 2014 한국세라믹학회지 Vol.51 No.5

Hydrous zirconia particles were prepared from ZrOCl2aqueous solution using an electro-dialysis [ED] process. For the preparationof (Zr,Y)(OH)4 precipitates, 3 mol% YCl3 was added into ZrOCl2aqueous solution. During the hydrolysis of 0.5 mol/L(Zr,Y)OCl2 solution at 90oC a slurry solution was obtained. The ED process was used for the removal of chlorine from the slurrysolution. Two kinds of slurry solution were sampled at the beginning and end of the ED process. The morphology of hydrous zirconiaparticles in the solution was observed using an inverted optical microscope and an FE-SEM. The hydrous zirconia particleswere nano-crystalline, and easily coagulated with drying. Yttrium stabilized zirconia [YSZ] powder could be obtained by the calcinationof (Zr,Y)(OH)4 precipitates prepared from a (Zr,Y)OCl2 solution by the ED process. The coagulated dry powders wereshaped and sintered at 1500oC for 2 h. The sintered body showed a dense microstructure with uniform grain morphology.

15년간의 담석환자 2,759예의 역학적 및 임상적 특징 분석

장명철,김기환,김선회,윤용범,박용현 大韓消化器病學會 1998 大韓消化器病學會誌 Vol.31 No.1

Hydroxyapatite-collagen 나노복합재료에서의 불균질 핵생성

장명철 한국세라믹학회 2001 한국세라믹학회지 Vol.38 No.11

공침법을 이용하여 수산화아파타이트[HAP]-콜라겐[COL] 나노복합재료를 제조하였다. HAP 결정과 COL 분자 사이의 화학결합형성을 확산반사법 FT-IR 및 투과전자현미경(TEM) 관찰로부터 확인하였다. 제조 시에 첨가되는 콜라겐 단백질의 농도가 높으면 미세한 아파타이트 나노결정의 콜라겐 복합체가 만들어지고 첨가되는 단백질의 농도가 낮으면 아파타이트 결정이 비교적 크게 발달하였다. FT-IR과 전자선 회절(electron diffraction)로부터 콜라겐 매체에 발달된 아파타이트 결정입자 들은 콜라겐 분자의 c 축을 따라 정렬하는 것임을 알 수 있었다. 칼슘이온 농도와 인산이온 농도를 일정하게 유지하는 수용액 계에 용해되어 있는 콜라겐 단백질의 농도는 아파타이트 결정의 발달을 위한 불균질 핵생성 위치를 제공하는 중요한 역할을 하고 있다. 콜라겐의 농도가 높으면 칼슘이온(Ca$^{2+}$)에 대한 핵생성을 위한 활성화 위치를 많이 제공하게 되며, 이는 핵생성 위치에 대한 칼슘이온 농도가 상대적으로 낮아지는 것에 대응하게 된다. Hydroxyapatite[COL] nanocomposite was prepared through coprecipitation process. The chemical bond formation between HAP and COL was confirmed by diffusive reflectance FT-IR and TEM observation. Higher concentration of COL in the preparation induced tiny nanocrystalline composite particles, but lower concentration of COL contributed to form the well developed HAP particles. From TEM observation and ED(Electron Diffraction) pattern the embedded HAP nanoparticles were oriented along the c-axis of COL fiber. In an aqueous system of constant [Ca$\^$2+/] and [PO$_4$$\^$3-/], quantity of soluble COL matrix was doing an important role of controlling the heterogeneous nucleation site for the formation of HAP nanocrystals. Higher concentration of COL will provide more nucleation sites for Ca$\^$2+/ and so the concentration of calcium ions for the total number of active nucleation sites will be getting relatively dilute.

거대 돌출형 비전형적 유방 수질암

장명철,김찬동,노혜린,채기봉,박원서,민동원,신형식,양대현,최원진 대한외과학회 2003 Annals of Surgical Treatment and Research Vol.65 No.4

A medullary carcinoma of the breast is an uncommon breast cancer subtype, but has a fair prognosis. The histopathological criteria for a medullary carcinoma were delineated by Ridolfi et al. in 1977, and most pathologists use these criteria. The authors experienced a huge carcinoma of the breast, which was diagnosed as an atypical medullary carcinoma. A 47-year old female visited our clinic due to a breast mass of six months duration. The mass was 16 cm in size and exophytic in the left lower breast. There had been necrosis, with a foul odor in most of the mass. A large fixed axillary lymph node was noted, but there was no evidence of distant metastasis. A radical mastectomy was performed due to invasion of the pectoralis major. On pathological examination, the tumor was diagnosed as an atypical medullary carcinoma. (J Korean Surg Soc 2003;65:353-355)

Development of Individual Survival Estimating Program for Cancer Patients’ Management

장명철 대한의료정보학회 2015 Healthcare Informatics Research Vol.21 No.2

Objectives: The goal of this report is to present an individual patient’s survival estimation curve using the each institution’s survival data after Cox proportional hazard analysis. Methods: The program was developed in three parts: input of basic data from Cox proportional hazard analysis, input of individual patient’s covariates, and presentation of individual patient’s survival curve. In the first part, the average survival rates with each survival time were entered as the means of covariates using the results of Cox proportional hazard analysis. In the second part, the individual patient’s values of each covariate were entered for the calculation of survival estimation. In the third part, the survival curve was displayed according to the input data. Results: The data of 2,652 breast cancer patients were analyzed. Cox regression analysis was conducted using the covariates of age, tumor size, N stage, and M stage. The individual patient’s survival curve was presented using the basic data and covariate factors. In the breast cancer patients, the program presented survival curves according to each patient’s age, tumor size, N stage, and M stage. The data of 251 thyroid cancer patients were analyzed by a similar method. Conclusions: We developed a program to present individual survival curves of cancer patients. This program will be useful for clinicians to assist their decision-making and discussion with patients.

Molecular Orbital Calculation on the Configuration of Hydroxyl Group in Hexagonal Hydroxyapatite

장명철 한국세라믹학회 2005 한국세라믹학회지 Vol.42 No.5

The possible configurations of hydroxyl group in hexagonal hydroxyapatite were identified through molecular orbital calculation. The molecular orbital interaction between O and H in hydroxyl column was analyzed using charge variation and bond overlap population (BOP). We supposed 5 kinds of O-H bond configurations as cluster types of I, II, III, IV and V. Mullikens population analysis was applied to evaluate ionic charges of O, H , P and Ca ions, and BOPs (Bond Overlap Populations) in order to discuss the bond strength change by the atomic arrangement. The stability of each O-H bond configuration was analyzed using bond overlap and ionic charge.

전자식안정기를 중심으로 한 고효율조명기기 품질인정 및 지원제도

장명철,김충환 전력전자학회 1999 전력전자학회지 Vol.4 No.3

종전에는 전력회사가 전력수요에 따라 공급설비를 확충하는데 중점을 두어 왔으나, 최근에는 미국 등 선진국을 중심으로 공급력을 확보하는 것과 같은 효과를 거두면서, 국가의 총 비용을 줄이는 수요관리 위주로 경영방향이 변화하고 있다. 한국전력공사는 전기이용효율 향상을 통한 수요관리방안으로 고효율기기 보급지원제도를 검토하고, 조명기기를 대상으로 장려금 지급방안을 마련하여 시행하고 있으며, 지원기기에 대한 품질의 신뢰성 확보를 위하여 기술규격과 품질인정제도를 제정하고 인정표시로 "고 마크"를 운용하고 있다.

한국인 주요 암의 개인별 발생 확률 예측 프로그램 개발

장명철,오승근 대한의료정보학회 2008 Healthcare Informatics Research Vol.14 No.4

Objective: This study was performed to develop a program for predicting individual cancer risk and to validate its discrimination power between case and control groups. Methods: The author used the five databases for searching journals about risk factors of six major cancers in Koreans: stomach, liver, colorectal, breast, uterine cervix and lung cancer. The risk models were selected from journals presenting a multivariate linear logistic regression analysis. The baseline hazards which had no risk factors were calculated, and a cancer risk assessment program was developed using relative risks based on risk factors' combination and baseline hazards. Case-control study was performed for five years to validate the program. Results: The discrimination power between case and control was 0.827 in stomach cancer, 0.949 in liver cancer, 0.594 in colorectal cancer, 0.587 in breast cancer, 0.708 in uterine cervix cancer and 0.663 in lung cancer. The estimated cancer probabilities were higher in all case groups compared to the control groups. Conclusion: The developed program is considered to be a valid tool for estimating probabilities of cancer development in Koreans. It is expected to be useful for the assessment of individual cancer risks, the selection of screening tools and preventive options for risk reduction.

제6기 국민건강영양조사 자료를 이용한 요중 요오드 농도와 갑상선 과산화효소항체의 분석

장명철 대한갑상선학회 2020 International Journal of Thyroidology Vol.13 No.2

Background and Objectives: This study was planned to investigate the relationship between iodine intake andthyroid peroxidase antibody in Korean population. Materials and Methods: We used the data of the 6th KoreaNational Health and Nutrition Examination Survey from 2013 to 2015. A total of 6564 subjects who had thedata of thyroid function test were included. We analyzed urinary iodine concentration and thyroid peroxidaseantibody using the complex sample method. Univariate and multivariate analysis were performed according toclinical factors and thyroid function tests. Results: In the multivariate analysis, the thyroid peroxidase antibodypositivity was not related to urinary iodine concentration in the total group (p=0.102), male group (p=0.245)and female group (p=0.098). The urinary iodine concentration was associated with thyroid stimulating hormone(TSH) (p=0.001) and free T4 (p=0.001) but not associated with thyroid peroxidase antibody (p=0.218). Whenhigh TSH group was divided into the positive and negative thyroid peroxidase antibody, high TSH group withnegative thyroid peroxidase antibody increased according to increasing urinary iodine concentration (p<0.001). But there was no difference in the high TSH group with positive thyroid peroxidase antibody (p=0.826). Conclusion: This study did not show a statistically significant relationship between urinary iodine concentrationand thyroid peroxidase antibody. As urinary iodine concentration increased, thyroid function was decreased onlyin the negative thyroid peroxidase antibody group. This confirmed that the increased urinary iodine concentrationcaused hypothyroidism which was not associated with thyroid peroxidase antibody.

에너지 절약과 전력수요관리

장명철 대한전기협회 1997 전기저널 Vol.247 No.-