• Korean Journal of Veterinary Research
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• v.45 no.4
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• pp.469-475
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• 2005

Cytogenetic and hematological analysis was performed in peripheral blood obtained from pigs bred in the high background radiation areas (HBRA) (Cheongwon-gun and Boeun-gun) and a control area. The frequencies of gamma-ray induced micronuclei (MN) in the cytokinesis-blocked (CB) lymphocytes at several doses were measured in three pigs. An estimated dose of radiation was calculated by a best fitting linear-quadratic model based on the radiation-induced MN formation from the swine lymphocytes exposed in vitro to radiation over the range from 0 mGy to 1,969 mGy. The measurements performed after irradiation showed dose-related increases in the MN frequency in each donors. The results were analyzed using a linear-quadratic model with a line of best fit of $y=0.0005404D^2+0.04237D+0.00833$ [y = number of MN/cytokinesis-blocked (CB) cells and D = irradiation dose in Gy]. MN rates per 1,000 CB lymphocytes of pig from the HBRA (Cheongwon-gun, Boeun-gun) and the control area were $6.70{\pm}2.36$, $9.00{\pm}3.50$ and $11.00{\pm}2.98$, respectively. The MN frequencies of CB lymphocytes from pigs bred in three areas means that the values are within the background variation in this experiment. The MN frequencies and hematological values were similar regardless of whether the pigs were bred in the HBRA or the control area.

• Applied Chemistry for Engineering
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• v.8 no.6
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• pp.1022-1028
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• 1997

This work was performed to study the characteristics of electrochemical intercalation reactions occurring at the interface between the organic electrolyte and tungsten trioxide thin film (thickness of $4000{\AA}$) prepared by e-beam evaporation method as cathodically coloring oxide with regard to the electrochromism by the intercalating reactions of the lithium cation in the 1M $LiClO_4/PC$ organic solution. The characteristics of electrochemical intercalation reactions were investigated by various DC electrochemical methods such as cathodic Tafel polarization test, multiple and the single sweep cyclic voltammetry and the coulomety titrations method. The surfaces of thin films were observed with the patterns of X ray diffraction after the coloring and bleaching reactions. In comparison with the previous results that $WO_3$ thin film intersely detached from the surface of electrode when the hydrogen cation was intercalated into $WO_3$ thin film in the o.1N $H_2SO_4$ aqueous solution, the intercalation reaction of lithium cation into $WO_3$ thin film in the 1M $LiClO_4/PC$ organic solution was shown that the stable bleaching and coloration was appeared within 1.0V of the applied overpotential. When the overpotential of electrochromic reaction for lithium cation in the 1M $LiClO_4/PC$ organic solution had been applied up to 1.5V, the accumulation phenomenon of lithium in amorphous $WO_3$ thin film layer occurred because the inserted lithium into amorphous $WO_3$ thin layer for coloring process was not fully removed from the thin layer to the electrolyte during bleaching process. It was found that there is a limitation of applied overpotential for coloring process by the reduction of the current densities of bleaching and coloration after few number of coloring and bleaching cycles.

• Journal of The Korean Association For Science Education
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• v.35 no.2
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• pp.333-342
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• 2015

This study analyzes the verbal interaction patterns used in a social network activity analysis that appeared in a science inquiry activity of 31 small groups of science-gifted students consisting of 5 members each. The results of this study are as follows: The interaction patterns showed eight types. The most prevalent interaction pattern, type 1, is triangle-shaped, interacting with 3 members out of 5 without a central member. Type 2 is wye form, interacting with 4 members and with one alienated member. Type 3 is diamond-shaped, interacting with 4 members. Type 4 is ray form, interacting with 5 around a central member. Type 5 has an alienated member and interacts with 4 members around the central member. Type 6 is triangle-branched, 4 members linked to the central member. Type 7 is wye form linked all around the central member. Type 8 is wye form with a more complex link than type 7. These can be classified in two. One is the participation-type where the rest of the 4 members are linked to the central member. The other is the alienation-type where a member/members is/are alienated without a central member. The participation-type appeared in 9 groups (29%), type 4, type 6, type 7, and type 8. The alienation-type showed in 22 groups (71%), type 1, type 2, type 3, and type 5. On the basis of this study, we propose that the best number of members in a group is three. It helps prevent a free-riding effect or isolation of members. Also, we deem it more fruitful if there is a member playing a central role in a group.

• Korean Journal of Cleft Lip And Palate
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• v.13 no.1
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• pp.1-10
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• 2010

구순구개열은 선천성 악안면 기형중에서 발생률이 가장 높은 질환이며 특히 동양인에게 높은 빈도로 발생된다. 그리고 순구개열에서는 파열부 조직의 선천적 상실과 파열부 봉합 수술 후 형성된 반흔에 의한 상악골의 열성장과 상악궁의 협착, 코의 형태 이상, 등과 함께 치아의 수, 크기와 형태 및 맹출 이상도 높은 빈도로 동반된다. 선천성 치아 발육 이상이 구순열 또는 구개열 가진 환자에게서 종종 보고되고 있다. 이런 치아 이상은 과잉치, 결손치, 크기, 형태, 맹출시기, 법랑질 광화 등의 많은 특징을 포함한다. 이번 연구의 목적은 다음과 같다. 1. 구순열 또는 구개열을 가진 환자의 선천성 치아 결손 발병률을 결정하여 정상인과 비교하는 것이다. 2. 상하악에서 파열이 있는 부위와 없는 부위의 제2소구치 결손가능성을 비교 하는 것이다. 구강악안면외과에서 구순구개열로 진단한 환자 중 2005년 1월~2009년 8월까지 전북대학교 구강악안면외과에서 치조열부위 자가골이식수술을 받은 32명의 환자로 초진시의 교정 chart, 구강악안면외과 chart, x-ray(파노라마, 치근단사진, 교합사진(상악), 석고 모델, 구강내 외 임상사진을 사용하여 순구개열군 별로 매복치, 과잉치, 결손치, 왜소치의 유무와 위치를 조사하여 다음과 같은 결론을 얻었다. 1. 결손치는 비교적 높은 발생빈도(53.1%)를 보였으며, 치아별 발생빈도는 상악 측절치와 상악 제2소구치, 하악 제2소구치 순이었다. 구순구개열군이 구순치조열군에 비해 발생률이 높게 나타났다. 그리고 구순구개열군 내에서 양측성이 편측성에 비해 결손치의 발생률이 높게 나타났다. 2. 왜소치는 71.6%에서 발견되었으며, 치아별 발생빈도는 상악측절치에서 가장 많았다. 구순치조열군이 구순구개열군에 비해 발생률이 높게 나타났다. 3. 치조열을 가진 환자에 있어 상/하악간 제2소구치의 선천적 결손에 유의한 차이가 있었다. 4. 구순구개열이 인접한 상악측절치의 발생중인 미성숙 조직에 영향을 미치며 파열부위와 좀 더 떨어져 있는 상악 제2소구치에도 일정한 영향을 미침을 이번 연구를 통해 다시 확인할 수 있었다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.68.1-68.1
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• 2012

The best part of graphene is - charge-carriers in it are mass less particles which move in near relativistic speeds. Comparing to other materials, electrons in graphene travel much faster - at speeds of $10^8cm/s$. A graphene sheet is pure enough to ensure that electrons can travel a fair distance before colliding. Electronic devices few nanometers long that would be able to transmit charge at breath taking speeds for a fraction of power compared to present day CMOS transistors. Many researches try to check a possibility to make it a perfect replacement for silicon based devices. Graphene has shown high potential to be used as interconnects in the field of high frequency electrical devices. With all those advantages of graphene, we demonstrate characteristics of electrical and optical properties of graphene such as the effect of graphene geometry on the microwave properties using the measurements of S-parameter in range of 500 MHz - 40 GHz at room temperature condition. We confirm that impedance and resistance decrease with increasing the number of graphene layer and w/L ratio. This result shows proper geometry of graphene to be used as high frequency interconnects. This study also presents the optical properties of graphene oxide (GO), which were deposited in different substrate, or influenced by oxygen plasma, were confirmed using different characterization techniques. 4-6 layers of the polycrystalline GO layers, which were confirmed by High resolution transmission electron microscopy (HRTEM) and electron diffraction analysis, were shown short range order of crystallization by the substrate as well as interlayer effect with an increase in interplanar spacing, which can be attributed to the presence of oxygen functional groups on its layers. X-ray photoelectron Spectroscopy (XPS) and Raman spectroscopy confirms the presence of the $sp^2$ and $sp^3$ hybridization due to the disordered crystal structures of the carbon atoms results from oxidation, and Fourier Transform Infrared spectroscopy (FTIR) and XPS analysis shows the changes in oxygen functional groups with nature of substrate. Moreover, the photoluminescent (PL) peak emission wavelength varies with substrate and the broad energy level distribution produces excitation dependent PL emission in a broad wavelength ranging from 400 to 650 nm. The structural and optical properties of oxygen plasma treated GO films for possible optoelectronic applications were also investigated using various characterization techniques. HRTEM and electron diffraction analysis confirmed that the oxygen plasma treatment results short range order crystallization in GO films with an increase in interplanar spacing, which can be attributed to the presence of oxygen functional groups. In addition, Electron energy loss spectroscopy (EELS) and Raman spectroscopy confirms the presence of the $sp^2$ and $sp^3$ hybridization due to the disordered crystal structures of the carbon atoms results from oxidation and XPS analysis shows that epoxy pairs convert to more stable C=O and O-C=O groups with oxygen plasma treatment. The broad energy level distribution resulting from the broad size distribution of the $sp^2$ clusters produces excitation dependent PL emission in a broad wavelength range from 400 to 650 nm. Our results suggest that substrate influenced, or oxygen treatment GO has higher potential for future optoelectronic devices by its various optical properties and visible PL emission.

• Journal of the Korean Chemical Society
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• v.37 no.1
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• pp.76-82
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• 1993

Two crystal structures of fully dehydrated Ca(II) and Tl(I) exchanged zeolite A, $Ca_{5.6}Tl_{0.8}-A (a = 12.242(2){\AA})\;and\;Ca_{1.4}Tl_{9.2}-A (a = 12.191(1){\AA})$, have been determined by single-crystal X-ray diffraction methods in the cubic space group Pm3m at 21(1)$^{\circ}C$. All crystals were ion exchanged in flowing streams of mixed $Ca(NO_3)_2\;and\;TINO_3$ aqueous solution with total concentration of 0.05M. All crystals were dehydrated at 360$^{\circ}C$ under $2{\times}10^{-6}\;torr$ for two days. The structures of the dehydrated $Ca_{5.6}Tl_{0.8}-A$ and $Ca_{1.4}Tl_{9.2}-A$ were refined to the final error indicies, $R_1$ = 0.072 and $R_2$ = 0.076 with 179 reflections for I > 3$\sigma$(I), and $R_1$ = 0.048 and $R_2$ = 0.043 with 226 reflections for I > 3$\sigma$(I), respectively. In each structure, Ca(II) ions are located on threefold axes associated with three 6-ring oxygens. $Ca^{2+}$ ions prefer to 6-ring sites and $Tl^+$ ions prefer to 8-ring sites when total number of exchanged cations per unit cell is more than 8.

• Bulletin of the Korean Chemical Society
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• v.30 no.8
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• pp.1703-1710
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• 2009

The single-crystal structure of |$Ca_{35.5}$|[$Si_{121}Al_{71}O_{384}$]-FAU, $Ca_{35.5}Si_{121}Al_{71}O_{384}$ per unit cell, a = 24.9020(10) $\AA$, dehydrated at 673 K and 2 ${\times}\;10^{-6}$Torr, has been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd$\overline{3}$m at 294 K. The large single crystals of zeolite Y (Si/Al = 1.70) were synthesized up to diameters of ${\mu}m\;and\;Ca^{2+}$-exchanged zeolite Y were prepared by ion exchange in a batch method of 0.05 M aqueous Ca($NO_3)_2$ for 4 hrs at 294 K. The structure was refined using all intensities to the final error indices (using only the 971 reflections for which $F_o\;>\;4{\sigma}(F_o))\;R_1$ = 0.038 (based on F) and $R_2$ = 0.172 (based on $F^2$). About 35.5 $Ca^{2+}$ ions per unit cell are found at an unusually large number of crystallographically distinct positions, four. Nearly filling site I (at the centers of the double 6-rings), 14.5 octahedrally coordinated $Ca^{2+}$ ions (Ca-O = 2.4194(24) $\AA$ and O-Ca-O = 87.00(8) and 93.00($8^o$) are found per unit cell. One $Ca^{2+}$ ion per unit cell is located at site II’ in the sodalite cavity and extends 0.50 $\AA$ into the sodalite cavity from its 3-oxygen plane (Ca-O = 2.324(13) $\AA$ and O-Ca-O = 115.5(10)o). The remaining twenty $Ca^{2+}$ ions are found at two nonequivalent sites II (in the supercages) with occupancies of 10 and 10 ions, respectively. Each of these $Ca^{2+}$ ions coordinates to three framework oxygens, either at 2.283(3) or 2.333(5) $\AA$, respectively, and extends either 0.24 or 0.54 $\AA$, respectively, into the supercage from the three oxygens to which it is bound. In this crystal, site I is the most populated; sites II’ and II are only sparsely occupied.$Ca^{2+}$+ appears to fit the octahedral site I best. No cations are found at sites III or III’, which are clearly less favorable for $Ca^{2+}$ ions in dehydrated zeolite Y.

• Journal of Community Nutrition
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• v.1 no.2
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• pp.98-107
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• 1999

The purpose of this study was to investigate Bone Mineral Density(BMD) and affecting factors on BMD of college women in Seoul. The subjects were 47 healthy college women aged 18-25 years. Antrophometric and body fat measurements were performed by Bioelectrical Impedance Fatness Analyzer(Tanita TVF 202). Blood pressure and pulse frequency were measured. Dietary intakes and general living habits were examined through questionnaires and nutrient intakes were analyzed by Computer Aided Nutritional Analysis(CAN) program for professional. Serum total cholesterol, TG(triglyceride), HDL-cholesterol, total protein, albumin, GOT, calcium were measured by Spotchem(SP-4410). Serum osteocalcin and alkaline phosphatase(ALP) were measured to monitor bone formation. BMD of lumbar spine(L2-L4), right hip(neck, ward's triangle, trochanter) and right forearm were measured by Dual Energy X-ray Absorptiometry(DEXA). Muscle strength was measured by examining leg flexion strength(right and left), leg extension power(right and left), handgrip power(right and left) and back strength. All data were statistically analyzed by the SAS PC package program. BMD of college women was normal(by WHO, 1994). Their muscle strength was bad(by national fitness guidebook, 1995). Only a mall number of them exercised (32.6% of subjects). There was no significant difference among BMD, muscle strength and % body fat(p<0.05). There were significant differences between BMD and total cholesterol as well as TG and VLDL-cholesterol(p<0.05). Total cholesterol was associated with decreasing BMD of the right forearm(p<0.05). TG and VLDL-cholesterol are associated with increasing BMD of right hip ward's triangle(p<0.05). There were significant differences among BMD, ALP and serum total protein. ALP was associated with decreasing BMD of the right forearm(p<0.05). There were significant differences between BMD and Ca as well as between Na and K intakes (p<0.05). Intakes of Na and K were associated with decreasing BMD of the right forearm (UD)(p<0.05). There were significant differences between in BMD and pulse frequently and serum albumin (p<0.05). Serum albumin is associated with increasing BMD of L3-L4(p<0.05), right hip neck(p<0.05). %Body fat, TG, VLDL-C, Ca intake, pulse frequency and serum albumin were associated with increasing BMD(p<0.05). Intakes of Na and K, ALP, total cholesterol, total cholesterol, total protein and height are associated with decreasing BMD(p<0.05). Overall results indicate that Ca intake but to be moderate in protein and Na intakes in order to increase BMD. Body exercise was recommended to increase BMD as well.

• International Journal of Oral Biology
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• v.42 no.4
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• pp.155-161
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• 2017

Teeth and bones are highly mineralized tissues containing inorganic minerals such as calcium phosphate, and a growing number of evidences show that their mineral content is associated with many diseases. Although the quantification of mineral contents by micro-computed tomography(micro- CT) has been used in diagnosis and evaluation for treating bone diseases, its application for teeth diseases has not been well established. In this study, we attempted to estimate a usefulness of a high-resolution micro-CT in analysis of human teeth. The teeth were scanned by using the Skyscan 1172 micro-CT. In order to measure tooth mineral content, beam hardening effect of the machine was corrected with a radiopaque iodine-containing substance, iodoacetamide. Under the maximum resolution of $6.6{\mu}m$, X-ray densities in teeth and hydroxyapatite standards were obtained with Hounsfield unit (HU), and they were then converted to an absolute mineral concentration by a CT Analyzer software. In enamel layer of cusp area, the mean mineral concentration was about $2.14mg/mm^3$ and there was a constant mineral concentration gradient from the enamel surface to the dentinoenamel junction. In the dentin of middle 1/3 of tooth, the mean mineral concentration was approximately $1.27mg/mm^3$ and there was a constant mineral concentration gradient from the outer of root to the pulp side, ranging from 1.3 to $1.06mg/mm^3$. In decay region of dentin, the mineral content was gradually decreased from the intact inner side to the decayed surface. These results suggest that high-resolution micro-CT can be as a useful tool for non-invasive measurement of mineral concentration in teeth.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.25 no.2
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• pp.423-435
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• 1995

The purpose of this study was to observe the effect of TGF-βl, which promotes differentiation and proliferation of osteoblasts, on bone regeneration. Experimental bone defects that measured 3 mm in diameter were created on the mandibles of guinea pig by removal of bone with the use of trephine burs. In one side of mandibular body, the experimental groups, bone defects were grafted with Biogran(Orthovita Co., U.S.A) and TGF-β1(R&D System Co., U.SA). In the remaining side of the mandiblar body, the control groups, bone defects were grafted with only Biogran. Guinea pigs in the control and experimental groups were serially terminated by fours on the 3 days, the 1 week, the 2 weeks, the 3 weeks, and the 4 weeks after experiment, and both sides of the mandibular bodies were removed and fixed with 10％ neutral formalin. They were decalcified and embedded in paraffin as using the usual method. The specimen sectioned and stained with hematoxylin and eosin. Also, they were radiographed with a soft X -ray apparatus. The obtained results were as follows; 1. Hemorrhagic condition, observed in the granulation tissues, disappeared on the 1 week after experiment in both groups, and more prominent in the experimental group. The granulation tissues of the experimental group had larger number of cells than those of the control group. 2. Osteoblastic differentiation in the margin of grafted material and adjacent bone was observed on the 1 week after experiment in both groups. Also, bone formation was observed in immature form on the 1 week after experiment. and more prominent in the experimental group. 3. In the polarizing microscopic examination, bone matrix was very loose on the 1 week after experiment, but increase in density with time, and more prominent in the experimental group. 4. In the microradiographic examination, newly formed bone was observed in the experimental group on the 2 weeks after experiment, and this was observed earlier than in the control group. Newly formed bone was increased with time and defected area was markedly decreased on the 4 weeks after experiment.