Morphology Development of HAp Crystallites in GEL Matrix

장명철 한국세라믹학회 2007 한국세라믹학회지 Vol.44 No.3

The crystal morphology of hydroxyapatite [HAp] phase in gelatin [GEL] matrices was investigated with the condition of a GELprecursor treatment in an aqueous solution of H 3PO4 at 37-80oC. Needle-shaped nanocomposite particles were prepared through adynamic reaction during a coprecipitation process using a phosphoric GEL solution. Various types of mineralized morphologyappeared with a phosphorylated condition of the GEL solution. HAp/GEL nanocomposite slurries showed the existence of an octa-calcium phosphate [OCP] phase during the process.

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.

올 여름의 전력수요

장명철 한국원자력산업회의 1993 원자력산업 Vol.13 No.10

Ba 변성 PMN-PT계 강유전체의 전계유기변위와 분극특성

장명철 한국세라믹학회 2000 한국세라믹학회지 Vol.37 No.1

Dielectric property of Ba-modified 0.65Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 ceramics having compositions near the morphotropic phase boundary was investigated. For the specimens having Ba contents between 0 and 20 at%, the average transition temperature was decreased linearly with increasing Ba contents and the degree of hysteresis was also decreased with increasing Ba contents. The maximum dielectric constants (K), electric field induced polarization(P) and electrically-induced strain(S) were found to exihibit a maximum value at∼3 at% of Ba. The increase of S and the decrease of hysteresis by minor additions of Ba impurities indicated the development of new higher perfomance actuator materials. The composition of Ba-PMN-PT (10/65/35) may be appropriate for capacitor materials because of low hysteresis and high polarization.

Bone Mineral Density in Thyroid Cancer Patients: Data from the Korea National Health and Nutrition Examination Survey

장명철 대한갑상선-내분비외과학회 2017 The Koreran journal of Endocrine Surgery Vol.17 No.4

Purpose: There are conflicting results about bone mineral density (BMD) after thyroidstimulating hormone (TSH) suppression in thyroid cancer treatment. This study used the Korea National Health and Nutrition Examination Survey (KNHANES) data to investigate BMD of thyroid cancer patients in Korea. Methods: The data were collected from 2008 to 2011 of the KNHANES IV–V. Among a total of 37,753 participants, 18,618 subjects were included. Osteopenia and osteoporosis were evaluated according the past history of thyroid cancer. Subgroups of women and postmenopausal women were analyzed using the same method. Results: Among the 18,618 subjects, 80 thyroid cancer cases were observed. There was no significant difference in osteopenia and osteoporosis with or without thyroid cancer history (P=0.783). In the subgroup analyses of women, no difference was observed in BMD according thyroid cancer history (P=0.685). In the post-menopausal women, osteopenia and osteoporosis were less frequent in thyroid cancer cases in univariate analysis (P=0.003), but that was not significant in multivariate analysis (P=0.095). Conclusion: Although the KNHANES had a small number of thyroid cancer cases, no data about TSH suppression, and short follow-up periods, no significant difference in BMD with or without thyroid cancer was observed. The subgroup analyses of women and postmenopausal women showed similar results.

La 변성 $Pb(Sc_{1/2}Nb_{1/2})O_3-PbTiO_3$계 요업체의 유전특성

장명철 한국세라믹학회 1999 한국세라믹학회지 Vol.36 No.12

Nitrogen Doping in Polycrystalline Anatase TiO2 Ceramics by Atmosphere Controlled Firing

장명철 한국세라믹학회 2019 한국세라믹학회지 Vol.56 No.4

A process for nitrogen doping of TiO2 ceramics was developed, whereby polycrystalline titania particles were prepared at 450– 1000oC with variation of the firing schedule under N2 atmosphere. The effect of nitrogen doping on the polycrystallites was investigated by X-ray diffraction (XRD) and Raman analysis. The microstructure of the TiO2 ceramics changed with variation of the firing temperature and the firing atmosphere (N2 or O2). The microstructural changes in the nitrogen-doped TiO2 ceramics were closely related to changes in the Raman spectra. Within the evaluated temperature range, the nitrogen-doped titania ceramics comprised anatase and/or rutile phases, similar to those of titania ceramics fired in air. Infiltration of nitrogen gas into the titania ceramics was analyzed by Raman spectroscopy and XRD analysis, showing a considerable change in the profiles of the N2- doped TiO2 ceramics compared with those of the TiO2 ceramics fired under O2 atmosphere. The nitrogen doping in the anatase phase may produce active sites for photocatalysis in the visible and ultraviolet regions.

La 변성 $Pb(Sc_{1/2}Nb_{1/2})O_3-PbTiO_3$계 요업체의 전계유기변위와 분극특성

장명철 한국세라믹학회 2000 한국세라믹학회지 Vol.37 No.1

Electrically-induced strain(S) and polarization(P) for Pb(Sc1/2Nb1/2)O3-PbTiO3(1-x)PSN-xPT) crystalline solutions were studied. From the compositional dependence of S and P we could observe two maximum values at x=0.10 and x=0.425. It is considered that PSNT10(x=0.10) composition is the structural phase boundary to indicate the variable order-disorder[VOD] region. PSNT(x=0.425) composition is the morphotropic phase boundary[MPB] to indicate the rhombohedral to tetragonal phase transition. Higher S (0.437%) and P (0.3974$\mu$C/$\textrm{cm}^2$) values were attained by the La substitution (5 wt%) at Pb site in the MPB composition of 57.5PSN-42.5PT.

Mineral trioxide aggregate bone cement based on wet‑prepared calcium silicate

장명철 한국세라믹학회 2020 한국세라믹학회지 Vol.57 No.1

To make tricalcium silicate (C3S), SiO2 precursors were mixed with Ca(OH)2 powder, and the mixtures were fired at 900 °C. One of the SiO2 precursors, H2SiO3, was prepared using Na silicate and HCl. Another precursor, Si(OH)4, was prepared using Si(OC2H5)4 and ethanol. Active Ca(OH)2 powder was prepared by hydration of CaO powder, which was obtained through calcination of CaCO3 powder. The obtained microcrystalline tricalcium silicate powders were mixed with CaSO4 ·1/2H2O to make mineral trioxide aggregate (MTA) bone cement for dental purposes. The MTA bone cement powders were stirred and hydrated with DI H2O, and the hardened sample blocks showed good compressive strength. For the test blocks, mechanical strength was measured using a universal testing machine, and microstructural phase analysis was done using FESEM and XRD. Cement hardening occurred through hydration, decomposition, and recrystallization of C3S and CaSO4 ·2H2O and resulted in grain growth.

Multiple Endocrine Neoplasia 2A Detected by Peptic Ulcer Perforation with Hypercalcemia

장명철 대한갑상선학회 2022 International Journal of Thyroidology Vol.15 No.2

Multiple endocrine neoplasia type 2A is autosomal dominantly inherited disease with RET oncogene mutation. Hyperparathyroidism occurs less frequently and severe hyperparathyroidism is rare in multiple endocrine neoplasia type 2A. We experienced a case of 38-year-old man with peptic ulcer perforation and hypercalcemia who was diagnosed as multiple neoplasia type 2A. Although peptic ulcer disease with hypercalcemia is very rare in MEN 2A, clinical suspicion of multiple endocrine neoplasia and germline mutational test would be important for accurate diagnosis and treatment.