• The Journal of Korean Academy of Prosthodontics
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• v.17 no.1
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• pp.47-59
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• 1979

In order to study the morphologic changes of the unfixed odontoblasts suspended in phenol solution of several different concentrations, the author carried out the extraction of lower incisor of S-D strain rats to collect the odontoblasts, and the cells obtained were suspended immediately in saline solution. After observing the odontoblasts in fresh state, the saline solution was substituted with 0.125%, 0.25% 0.5%, 1% and 2% diluted phenol solutions. The morphologic changes were examined with phase contrast microscope at intervals of 10, 30, and 60 minutes. The results were as follows: 1. In saline solution the odontoblast showed cytoplasmic swelling, slender cytoplasmic process, thick rim nuclear membrane with increased dark contrast, and prominent nucleoli and chromatin granules with lapse of time intervals. In accordance with time intervals, blisters appeared in the supranuclear zone and increased its size and moved outward of the cytoplasmic membrane resulting detachment from the cell membrane. The phase dark cytoplasmic granules were increased in its dark contrast and in its size. 2. In 0.125% and 0.25% phenol solution, the odontoblasts and its nucleus shrunk immeidately and its contrast of cellular components was increased. With the lapse of time, the phase-dark granules in cytoplasm were aggregated, and several blisters were formed in and out of the cells. The outline of cytoplasmic membrane was also obscured. 3. In 0.5% phenol solution, the necleus shrunk at once, but soon after it revealed karyolysis accompanying dark contrast of neclear components such as nuclear membrane, nucleoli, and chromatin granules. On the contrary, the cytoplasmic granules showed aggregation and increased dark contrast, small and large blisters were formed in and out of the odontblasts and the outline of cytoplasmic membrane became obscured. 4. In 1% phenol solution, it showed shrinkage of odontblasts and its nuclei with thick rim nuclear membrane, aggregation of chromatin granules and occasional karyorrhexis. The dark contrast of cytoplasmic granules was increased and aggregated each other. But the blister formation could not be found. 5. In 2% phenol solution, it showed the shrinkage of odontoblasts and pyknotic nuclei with increased dark contrast of nucleoli and chromatin granules. The number of cytoplasmic granules was decreased by aggregation. But the blister formation could not be found as in 1% phenol solution.

• Journal of Korean Society of Forest Science
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• v.71 no.1
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• pp.14-21
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• 1985

This study was carried out in order to prevent the devaluation of wood itself and wood products causing by anisotropy, hygroscopicity, shrinkage and swelling - properties that wood itself only have, in order to improve utility of wood, by emphasizing the natural beautiful figures of wood, to develop the dimensional stabilization techniques of wood with PEG that it is a cheap, non-toxic and the impregnation treatment is not difficult, on the effects of PEG molecular weights (200, 400, 600, 1000, 1500, 2000, 4000, 6000) and species (Pinus densiflora S. et Z., Larix leptolepis Gordon., Cryptomeria japonica D. Don., Cornus controversa Hemsl., Quercus variabilis Blume., Prunus sargentii Rehder.). The results were as follows; 1) PEG loading showed the maximum value (137.22%, Pinus densiflora, in PEG 400), the others showed that relatively slow decrease. The lower specific gravity, the more polymer loading. 2) Bulking coefficient didn't particularly show the correlation with specific gravity, for the most part, indicated the maximum values in PEG 600, except that the bulking coefficient of Quercus variabilis distributed between the range of 12-18% in PEG 400-2000. In general, the bulking coefficient of hardwood was higher than that of softwood. 3) Although there was more or less an exception according to species, volumetric swelling reduction was the greatest in PEG 400. That is, its value of Cryptomeria japonica was the greatest value with 95.0%, the others indicated more than 80% except for Prunus sargentii, while volumetric swelling reduction was decreased less than 70% as the molecular weight increase more than 1000. 4) The relative effectiveness of hardwood with high specific gravity was outstandingly higher than softwood. In general, the relative effectiveness of low molecular weight PEG was superior to those of high molecular weight PEG except that Quercus variabilis showed more than 1.6 to the total molecular weight range, while it was no significant difference as the molecular weight increase more than 4000. 5) According to the analysis of the results mentioned above, the dimensional stabilization of hardwood was more effective than softwood. Although volumetric swelling reduction was the greatest at a molecular weight of 400. In the view of polymer loading, bulking coefficiency reduction of swelling and relative effectiveness, it is desirable to use the mixture of PEG of molecular weight in the range of 200-1500. To practical use, it is recommended to study about the effects on the mixed ratio on the bulking coefficient, reduction of swelling and relative effectiveness.

• Journal of the Korean Wood Science and Technology
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• v.21 no.4
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• pp.45-54
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• 1993

This study examines the differences in structures, physical and mechanical properties between domestic(Quercus variabilis Blume) and foreign(Quercus suber L.) corks. The results obtained are as follows: 1. The cork tissue consists of cork cells, lenticels, sclereids and dark-brown zone. There was a significant difference in ratio of cork cells between foreign cork(93 %) and domestic cork(87 %). The ring width and width of late cork of the foreign cork were wider than those of domestic cork. But the percentage of late cork of domestic cork was richer than that of foreign cork. The size of cork cell of foreign cork was larger by about two times than that of domestic cork. 2. The density was slightly higher in domestic cork(0.22 g/$cm^3$) than in foreign cork(0.19 g/$cm^3$). During first 24 hours, the amount of water absorption of the foreign cork was greater than that of domestic cork. However, after 24 hours, the tendency was reversed. The level of EMC was higher in domestic cork than in foreign cork. Total shrinkage in the radial and tangential directions was larger in domestic cork than tn foreign cork. In the longitudinal direction, the tendency was reversed. There was no difference in total swelling in three woody directions between the two corks. 3. The modulus of elasticity in compression in the logitudinal and tangential direction was higher in domestic cork than in foreign cork, but the tendency was reversed in the radial direction. Both corks showed 95% of recovery rate after 24 hours when they were compressed by 0.5. There were no differences in tension strength and Brinell,s hardness bet ween domestic and foreign corks.

• Journal of Conservation Science
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• v.17 s.17
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• pp.19-32
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• 2005

The exterior of Korean traditional wooden buildings have been painted with Danchung of painting method using glue and pigments. However because of losing traditional techniques and materials through the period of colonization and industrialization, many problems are occurring today. Especially after several years from painting, occurrence of scalings and flakings in painting layer is a serious problem. To improve weathering resistance of painting layer caused by stress from the difference of swelling and shrinkage between painting layer and wood plate, was examined by weathering tests. The stress is due to the hydrophilic property of wood, mechanical properties(tensile property and stress relaxation) of painting layer, and priming methods by various binders such as glue, acrylic emulsion(Primal AC-3444), acrylic resin(Paraloid B-72). Because stress relaxation of acrylic emulsion of which glasf transition temperature is below room temperature$(7^{\circ}C)$ is high, painting layers with acrylic emulsion generate no scalings and flakings and are in the most durable state in all weathering tests. Priming method which starts from low concentration to high concentration, is more effective to improve durability than other priming methods.

• Journal of the Korean Society of Clothing and Textiles
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• v.11 no.2 s.24
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• pp.101-112
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• 1987

The purpose of this study is to investigate the influence of addition of sodium dodecyl sulfate(SDS) when wool is treated with sodium hydroxide(NaOH). Physical and chemical changes were examined on wool treated with various cone. of NaOH and SDS simultaneously. The result are as follows. 1. The higher the temperature and the longer the time of NaOH treatment are, the more alkali damage wool get : increase in weight loss and decrease in urea-bisalphite solubility and in tensile strength. But the treatment time reacts less effective than the temperature. 2. When wool is treated with NaOH, at NaOH cone. under $10^{-3}M$., the addition of SDS alleviates the alkali reaction on wool: increase in cystine contents and in urea-bisulpite solubility, and decrease in degree of swelling. On the other hand, at NaOH cone. over $10^{-2}M$., the addition of SDS promotes the alkali reaction on the wool. 3. When wool is treated with NaOH, the addition of SDS shows no changes on the tensile strength. On the other hand, at NaOH cone. under $10^{-2}M$., the addition of SDS shows no changes on the softness of wool, but at the $10^{-1}M$. NaOH cone. addition of SDS increases the soft-ness of wool. The area shrinkage of wool treated with NaOH and SDS shows less changes than with NaOH only.

• The Korean Journal of Zoology
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• v.21 no.3
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• pp.87-102
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• 1978

Electron microscopic studies were made to investigate changes in the fine structure of the liver, kidney and gills of Carassius carassius L. following exposure to 1 and 2.5 ppm of $HgCl_2$. The following results were obtained: 1. In the mercury-treated liver cells, an increase in the number of lysosomes were noticed. These lysosomes appeared to be of two types; round ones containing some crystalline structures and others with phagocytosed glycogen granules and mitochondria. Also observed were mitochondrial swelling where the matrix appeared less electrondense, and segregation of the nucleoli in the nucleus. 2. In the kidney, mercury treatment resulted in thickening of the basement membrane of the glomerulus, and appearance of vacuoles and cytoplasmic bodies in the proximal convoluted tubule. The vacuoles seemed to be formed from mitochondria. Nuclear shrinkage was also noticed at 2.5 ppm of $HgCl_2$. 3. Many large and small lysosomes appeared in response to mercury in the epithelial cells of the gill lamella. Also the lamellar membrane became fuzzy in appearance. 4. It can be concluded from these results that mercury-induced changes in the fine structure are associated with activation of detoxication processes and impairment of energy metabolism.

• Journal of the Korean Wood Science and Technology
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• v.30 no.2
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• pp.95-101
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• 2002

Physical and mechanical properties of major Korean ash species were examined. For Fraxinus rhynchophylla and Fraxinus sieboldiana, green moisture content of sapwood was almost the same value as heartwood. Heartwood of Fraxinus mandshurica, however, had slightly higher moisture content than sapwood. Green and oven dry densities of F. mandshurica were lower than those of F. rhynchophylla and F. sieboldiana. Swelling and shrinkage of sapwood in F. sieboldiana showed somewhat higher value than those of F. rhynchophylla. Longitudinal compressive strength and modulus of elasticity in F. sieboldiana were lower values than those in the other species. Shearing strength in radial section was higher than that in tangential section of all samples. It could be noted that shearing strength of F. sieboldiana demonstrated higher value than that of the other species. Three species had excellent bending properties in MOR and MOE. Impact bending absorbed energy for F. rhynchophylla and F. mandshurica did not show any significant differences.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.9
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• pp.199-206
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• 2019

Experimental study on the durability characteristics to examine the feasibility of concrete with high water-tightness and self-healing performance to minimize maintenance of concrete for artificial ground is as follows. 1) When blending agent, swelling agents, and curing accelerator were added on the ternary system cement with blast-furnace slag fine particles and fly ash to give a self-healing property, higher blending strengths by 82% at design standard strength of 24MPa and by 74% at design strength of 30MPa, respectively could be obtained. 2) The permeability test for the specimens having high water-tightness and no shrinkage showed that the permeability was reduced at maximum of 98%. However, the permeability was decreased as the design strength was increased, showing the reduction rate of 87% at the design strength of 50MPa. 3) The depth of carbonation of blast-furnace slag and fly ash was increased in all the specimens compared with those of OPC only. However, as the material age was increased, carbonation penetration depth was decreased compared with the reference blend. 4) Compared with the reference blending using only OPC, the freeze-thaw resistance was higher in the case of blending with 40% of blast-furnace slag and 10% of fly ash at the design standard strength of 50MPa. In addition, the freeze-thaw resistance in general was superior in the design standard strength of 50MPa with the lower water-binder ratio (W/B) as compared with the design standard strength of 24MPa and 30MPa with the high water-binder ratios.

• Journal of Forest and Environmental Science
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• v.17 no.1
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• pp.37-46
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• 2001

The objective of this work is to examine anatomical and physical characteristics of wood damaged by pine needle gall midge(PNGM, Thecodiplosis japonensis Uchida et Inouye) in Pinus densiflora. In anatomical characteristics, it was noted that the number of axial and radial resin canals in the damaged wood was higher than that in sound wood. In damaged wood, green moisture content of sapwood and swelling and shrinkage was higher than sound wood. Both longitudinal compressive strength and bending strength of the damaged wood were lower than those of sound wood. On the other hand, shearing strength of damaged wood was similar to that of sound wood.

• Journal of Environmental Science International
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• v.20 no.10
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• pp.1221-1232
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• 2011

We investigated the toxic effects of difenoconazole on the development in the African clawed frog, Xenopus laevis. To test the toxic effects, frog embryo teratogenesis assays using Xenopus were performed. Embryos were exposed to various concentrations of difenoconazole (0-30 ${\mu}M$). $LC_{100}$ for difenoconazole was 30 ${\mu}M$, and the $LC_{50}$ determined by probit analysis was 27.19 ${\mu}M$. Exposure to difenoconazole concentrations ${\geq}$5 ${\mu}M$ resulted in 10 different types of severe external malformation. Histological examinations revealed dysplasia of the eye, heart, liver, somatic muscle, and swelling of the pronephric ducts. The tissue-specific toxic effects were investigated with an animal cap assay. Blood cells were normally induced at a high frequency by mSCF and activin A. However, the induction of blood cells was strongly inhibited by the addition of difenoconazole. Electron micrographs of tested embryos showed the degeneration of somatic muscle and the shrinkage of microvilli on pronephric duct. The gene expression of cultivated animal cap explants was investigated by reverse transcriptase-polymerase chain reaction (RT-PCR). It revealed that the expression of the blood-specific marker(${\beta}$-globin II) and muscle-specific marker (XMA) were more strongly inhibited than the neural-specific marker(XEn2) by the addition of difenoconazole.