• Journal of the korean academy of Pediatric Dentistry
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• v.21 no.2
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• pp.439-455
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• 1994

The purpose of this study was to investigate the distribution of nerves in the periodontal ligament of a dog's primary teeth by each developing stage. The distribution of nerves in the periodontal ligament were investigated by means of immunohistochemistry for detection of neurofilament protein (NFP). The results were as follows: The NFP-immunoreactive nerve fibers were found to be densely distributed in the apical third of the periodontal ligament, while they were sparse in the coronal two third, in both primary and permanent teeth. In generally the density of distribution and degree of arborization of nerve fibers in periodontal ligament of primary teeth revealed a poor appearance compared with that of permanent teeth. Periodontal ligament in anterior teeth showed more abundant nerve innervation than posterior teeth, and the periodontal ligament of the bifurcation area in posterior teeth roots were not observed to have nerve fiber. The density of nerve distribution in the periodontal ligament of primary teeth was reduced according to the physiological root resorption and nerve fibers were not observed in the surrounding area on the root of the exfoliation stage in primary teeth. The distribution of nerve fibers in mucogingival tissue, was poor innervated according to the aging of the dogs. A more abundant distribution of nerve fiber was represented in the lingual mucogingival tissue than in the labial side. Most of the nerve endings in the periodontal ligament of primary teeth showed a tree-like appearance. However, the typical Ruffini-like nerve endings were not observed.

• Economic and Environmental Geology
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• v.39 no.6 s.181
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• pp.629-641
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• 2006

The Standing Buddha Statue in the Gwanchoksa temple consists of medium to coarse grained biotite granodiorite with dark grey color, and it has a week gneissosity along the pegmatite veins. The results of magnetic susceptibility and geochemical patterns of the host rock of Standing Buddha Statue and the basement rock suggest that both values are formed from the co-genetic magma with the same differentiation process. The CIAs of the basement rock and the Standing Buddha Statue are calculated to 51.43 and 50.86, and the WPIs are estimated 4.52 and 8.95, respectively. So the weathering potential from the host rock of Standing Buddha Statue and basement rock prove to be high. The Standing Buddha Statue is terribly damaged with physical weathering from deterioration and exfoliation, and are scattered with secondary pollutant and precipitate. Basement rock is also in danger of ground collapse because of irregularly developed discontinuity system. Most surface of Standing Buddha Statue is seriously discolored into yellowish brown and dark gray, or black precipitates are also formed. Moreover, it is heavily covered with crustose lichen, fungi and algae, or moss are also found. In order to control the influential factors with the complex deterioration of Standing Buddha Statue, it is needed to rearrange a site environments, and conservation scientific management is required to protect it from covering lichens, exfoliations and fractures.

• Environmental Analysis Health and Toxicology
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• v.15 no.4
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• pp.123-130
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• 2000

2-Bromopropane, important industrial chemical, specially in electronic industry at Yangsan in Korea has been reported to cause amenorrhea for female and azoospermia, oligozoospermia or reduced sperm motility for male. 2-BP was investigated through 21 days of repeated dose in male Sprague-Dawley rats. The dose levels per body weight were 0 (control), 250,500 and 1,000 mg/kg. 2-BP dissolved in vehicle olive oil was injected into the intraperitoneum 6 times per week for 3 weeks, but 1,000 mg/kg dose group was 2 weeks because of serious illness. Male rats showed significant decreases in body weight and right and left testis showed typical weight losses depending on the 2-BP. The number of white blood cell and red blood cell , percentage of monocytes, and hemoglobin decreased significantly in high dose (P< 0.05). Red cell volume distribution width increased significantly in the high dose (P< 0.05). Histopathological findings of testes showed a decrease of spermatogenic cells, exfoliation of spermatid and spermatocyte, vacuolization of Sertoli cells and hyperplasia of Leydig cells. Protein band density between 113,000 dalton ($\beta$-galactosidase) and 53,900 dalton (ovalbumin) has decreased in 250 mg/kg dose group, but it has gradually increased to the higher density in 1,000 mg/kg dose group than in control group.

• Journal of Conservation Science
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• v.17 s.17
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• pp.39-56
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• 2005

The Gwangtonggyo(bridge) on the Cheonggyecheon(river) is mainly composed of biotite granite with coarse grain. The rock consists mainly of quartz, plagioclase, microcline, orthoclase and biotite with lesser amount of muscovite, sericite and chlorite. Muscovite and sericite may be formed from feldspars and chlorite from biotite by alteration(including weathering). These rocks are relatively deteriorated by weathering, polluted water running the river and heavy traffic. The main phenomena of damages are surface exfoliation, grain separation, deceleration, pollution of organic and heavy chemical elements, cracks and breakage. These phenomena have been analyzed by polarized microscope, XRD and SEM/EDX. The analyzed results show organic pollution and secondarily formed gypsum and apatite on the rock surface and micro-pores. NaCl and $CaCO_3$ as rock salt and calcite probably may be formed secondarily in some points. Also heavy chemical elements such as Cr, Pb, Pd, W, La, Zn and Nd are polluted in some samples. The contacts between rocks are generally breakdown in small scale or cracks are developed due to mainly load and vibration shock of heavy traffic.

• Journal of Conservation Science
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• v.16 s.16
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• pp.77-88
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• 2004

This study evaluates the occurrences, phyfical weathering and biological deterioration on rock properties during the dissection process an object of stone pagoda in the Mireuksaji temple site. For restoration and conservation, all kinds of rock properties are carried out detailed scientific investigation and diagnosis. Constituting rocks of the pagoda composed mainly of equi-granular medium grained biotite that rock properties presumed to be use about 3,000 materials. Main external properties of the pagoda are total 446 materials, and the rock properties under the concentration load on the each floors occurred with overlapping fracture, weathering and deteriorations. The 84 materials show highly degraded about $18.8\%$ among the external properties. Representative physicochemical deteriorations are fracture, loss, break, exfoliation, degradation, grain shaped dissolution, relief surface, discoloration and hydroxide precipitates, in this study, the deterioration state of each properties give a precisely description and analysis. Coverage of lichen and algae on the rock surface represented about $85\%$. As the some properties, biological contaminants withered up when spray rock surface with diluted cleaning chemicals. Results of the study are utilized an application for restoration system and detailed investigation during the dissection process of stone cultural properties.

• Journal of Conservation Science
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• v.27 no.2
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• pp.223-229
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• 2011

Buddha painting cultural properties couldn't avoid the change of colors and the exfoliation phenomenon by the characteristic of material and environmental factors. Especially, because in the beginning of the fine crack and the decoloration phenomenon on the surface of pigment would be significantly decrease stability of the whole object, it is necessary to take particular measure. Therefore, this is a study on conservation of Avalokitesvara in Potalaka in Hyeondeungsa in Gapyeong. It treated damaged parts of the object, carried out backing papers and matching colors. And then, it examined scientific analysis of pigments. Also, it performed nondestructive testing like XRF, FT-IR, and image microscope to investigate the quality of the material of hanji using the object and the component and characteristic of pigments. As a result, FT-IR spectrum matching Korean traditional paper(hanji) was detected in hanji of Avalokitesvara in Potalaka in Hyeondeungsa. The black pigment making a thin layer over the white pigment would estimate carbon compounds of unconfirmed ink stick or soot as XRF and FT-IR. Also, the white pigment was lead white($PbCO_3{\cdot}Pb(OH)_2$) involving Pb(Lead) and a carbonate. It was observed that the crystal of blue pigment had the different sizes of the particles from the microscope. In the case of this blue pigment, it showed cobalt blue and lead white was mixed when it used because both Cu and Pb were highly detected in XRF data.

• Polymer(Korea)
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• v.36 no.3
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• pp.251-261
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• 2012

The nanocomposites containing graphene oxide flakes were prepared in order to improve the mechanical properties of artificial marbles based on poly(methyl methacrylate)(PMMA) matrix. Graphene oxide flakes were prepared from graphite by oxidation with Hummers method followed by exfoliation with thermal treatment. Surface of graphene oxide flakes were modified with oxyfluorination in various oxygene:fluorine compositions to improve the interfacial compatibility. The nanocomposites containing graphenes modified with oxyfluorination in the oxygen content of 50% and higher showed the significant increase in flexural strength, flexural modulus, Rockwell hardness, Barcol hardness, and Izod impact strength. The morphology of fractured surface showed the improved interfacial adhesion between PMMA matrix and the graphenes which were properly treated with oxyfluorination. The mechanical properties of nanocomposite were deteriorated by increasing the content of graphene above 0.07 phr due to the nonuniform dispersion of graphenes.

• Journal of the Mineralogical Society of Korea
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• v.17 no.3
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• pp.189-199
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• 2004

Cretaceous sedimentary rocks bearing dinosaur tracks in the Goseong interchange area were studied for their conservation and public display in the aspect of applied mineralogy. Black clay layers alternate with silt layers in the sedimentary rocks. The verical and horizontal fissures are commonly filled with calcite veinlets, supergenetic iron and manganese oxides. The rocks are composed of quartz, albite, K-feldspar, calcite, chlorite, illite, muscovite, and biotite, with minor apatite and rutile. Silt layers are relatively rich in calcite and albite, whereas clay layers are abundant in quartz, illite, and chlorite. Al, Fe, Mg, K, Ti, and P are enriched in the clay layers, while Ca, Na, and Mn in silt. Most of trace elements including V, Cr, Co, Ni, Cs, Zr, REE, Th, and U are enriched in clay layers. Inorganic carbon are present in silt layers as calcite, while organic carbon in black clay layers. The black clay layers were partly altered to yellow clay layers along the fissures, simultaneously with the decrease of organic carbon. Selective exfoliation of clay-rich black and yellow clay layers, calcite matrix of silt layers and calcite infillings of fissures are estimated as the major weakness potentially promoting chemical and physical degradation of the track-bearing rock specimens.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.1
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• pp.14-19
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• 2013

We have successfully synthesized $Bi_{4-x}La_xTi_3O_{12}$ (x~2) having Aurivillius-type layered perovskite structure from exfoliated layered perovskite oxide of $K_2La_2Ti_3O_{10}$ with Ruddlesden-Popper structure. The reaction between the exfoliated lanthanum titanate nanosheets and BiOCl nanocrystal resulted in the formation of polycrystalline $Bi_{4-x}La_xTi_3O_{12}$ (x~2) after heating above $700^{\circ}C$. Colloidal suspension of the nanosheets could be obtained by intercalating ethylamine (EA) into the protonated lanthanum titanate, $H_2La_2Ti_3O_{10}$, derived from $K_2La_2Ti_3O_{10}$. Transmission electron microscopic (TEM) analysis show that the exfoliated lanthanium titanate nanosheets have a thickness of a few nano meters. According to X-ray diffraction (XRD) analysis, the exfoliated lanthanium titanate was found to be transformed into $Bi_{4-x}La_xTi_3O_{12}$ (x~2) after restacking with BiOCl and subsequent thermal treatment at > $700^{\circ}C$.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.3
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• pp.309-318
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• 2012

In advanced stages of periodontal disease, a lot of the periodontal tissue support are usually lost. The tissue destruction around some teeth is progressed to a level which requires either spontaneous exfoliation or extraction of several teeth due to their excessive mobility. In such cases, a comprehensive treatment plan encompassing the adequate periodontal and maintenance therapy, as well as perio-prosthetic treatment involving occlusal equilibration, is needed in order to restore health, function, and esthetics. Cross-arch fixed partial dentures(CAFPDs), one of the perio-prosthetic treatments, are used to stabilize the teeth with severely reduced periodontal tissue support. Unfortunately, however, a little is known about the occlusal scheme and biomechanical concept of CAFPDs. This paper will demonstrate summaries of the trauma from occlusion(TFO), Ante's law revisited, the treatment principles, the role of occlusion, and the long-term consequences for CAFPDs, and the possibility of CAFPDs through a case presentation.