• Composites Research
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• v.35 no.1
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• pp.47-51
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• 2022

In order to efficiently control the heat generation of electronic devices, many research has been conducted on thermally conductive composite materials. In this study, milled carbon fiber was dispersed in four solvent to investigate the relationship of carbon fiber alignment according to dispersion by solvents, and carbon fiberreinforced composite material(CFRP) was manufactured using vacuum filtration. To evaluate the arrangement of CFRP the arrangement of the prepared specimen was observed under an optical microscope, and thermal conductivity was measured by Laser Flash Analysis. The Through-plane thermal conductivity of CFRP using NMP and Ethanol was 10.79 W/mK and 10.57 W/mK respectively, which were improved by 218% and 209% compared to the In-plane thermal conductivity. The high viscosity of the solvent greatly affects the shear of the fluid, and it seemed to determine the alignment of the filler.

• The KIPS Transactions:PartB
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• v.16B no.5
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• pp.341-346
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• 2009

The motion data glove is a representative human-computer interaction tool that inputs human hand gestures to computers by measuring their motions. The motion data glove is essential equipment used for new computer technologiesincluding home automation, virtual reality, biometrics, motion capture. For its popular usage, this paper attempts to develop an inexpensive visual.type motion data glove that can be used without any special equipment. The proposed approach has the special feature; it can be developed as a low-cost one becauseof not using high-cost motion-sensing fibers that were used in the conventional approaches. That makes its easy production and popular use possible. This approach adopts a visual method that is obtained by improving conventional optic motion capture technology, instead of mechanical method using motion-sensing fibers. Compared to conventional visual methods, the proposed method has the following advantages and originalities Firstly, conventional visual methods use many cameras and equipments to reconstruct 3D pose with eliminating occlusions But the proposed method adopts a mono vision approachthat makes simple and low cost equipments possible. Secondly, conventional mono vision methods have difficulty in reconstructing 3D pose of occluded parts in images because they have weak points about occlusions. But the proposed approach can reconstruct occluded parts in images by using originally designed thin-bar-shaped optic indicators. Thirdly, many cases of conventional methods use nonlinear numerical computation image analysis algorithm, so they have inconvenience about their initialization and computation times. But the proposed method improves these inconveniences by using a closed-form image analysis algorithm that is obtained from original formulation. Fourthly, many cases of conventional closed-form algorithms use approximations in their formulations processes, so they have disadvantages of low accuracy and confined applications due to singularities. But the proposed method improves these disadvantages by original formulation techniques where a closed-form algorithm is derived by using exponential-form twist coordinates, instead of using approximations or local parameterizations such as Euler angels.

• Journal of Yeungnam Medical Science
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• v.10 no.2
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• pp.313-337
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• 1993

The aim of this study was to clarify the role of Kupffer cells in the mechanism of endotoxin-induced liver injury. The study on fine structure of Kupffer cells was performed after the injection of endotoxin. The endotoxin(Escherichia coli lipopolysaccharide 026 : B6. 1.5mg/100 g of body weight) was intraperitoneally injected in Sprague-Dewley rats. Animals were sacrificed at 1/4, 1/2, 1, 2, 4, 8, 16, 24, 72 and 120 hours after the injection of endotoxin. Livers were extirpated and processed to be examined by light and electron microscopy. The results obtained were summerized as follows: Early changes observed in liver after endotoxin injection included the increased number and hypertrophy of Kupffer cells, infiltration of neutrophils and presence of fibrin thrombi within the sinusoids. The continuous increase of the Kupffer cells in number with hypertrophy, congestion and infiltration of inflammatory cells within the sinusoids were observed. Hepatocytes showed fatty change and occasional necrosis. At 72 hours the congestion decreased. At 120 hours the number of Kupffer cells was increased, but the morphology of Kupffer cells became similar to that of the control group. The numbers and sizes of primary and secondary lysosomes and amount of euchromatin of Kupffer cells increased. Swellings and increase in number of mitochondria, Golgi complex, smooth endoplasmic reticulum, rough endoplasmic reticulum were evident. Microthrombi were present within the sinusoids. The swelling of rough endoplasmic reticulum and mitochondria, decrease of glycogen particles, fatty change, hypoxic vacuoles, pyknotic nuclei and occasional necrosis were observed in hepatocytes. At 72 hours the number of secondary lysosomes in Kupffer cells decreased. At 120 hours the morphology of Kupffer cells became similar to that of the control group. According to these results, it was postulated that the endotoxin was initially taken up by pinocytosis into Kupffer cells and degraded in secondary lysosomes of activated Kupffer cells. Kupffer cells may play an important role in the defense mechanism of liver during endotoxemia. The dysfunction of Kupffer cells and ischemia by sinusoidal microthrombi may cause liver injury.

• Applied Microscopy
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• v.29 no.2
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• pp.137-147
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• 1999

Comparative differences between the fine structure of cultured LL/2 cell in vitro and tumor cells in vivo which were induced in the lung by inoculation of LL/2 cells to C57 BL/6 mouse via tail vein during 21 days are not observed except for cell configuration which was changed spindle shape into oval shape. At first tumor cells appeared at lymphatic nodules and around capillary in the lung. Tumor cells divided actively by mitosis, so they became tumor nodules. The pulmonary aveoli around tumor nodules were observed somewhat flattened in shape but the cells in the aveoli appeared to be in normal condition. Furthermore the normal lung cells were observed in the tumor nodules and some apoptotic tumor cells appeared in the large tumor nodules. A lot of neutropiles were observed in the aveoli and tumor nodules of C57 BL/6 mouse lung after inoculation 22 days and 31days.

• Tuberculosis and Respiratory Diseases
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• v.42 no.1
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• pp.58-66
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• 1995

Background: Acute interstitial pneumonia is a relatively rare form of interstitial pneumonia, since the vast majority of interstitial pneumonia have a more chronic course. It corresponds to the lesion described by Hamman and Rich, as Hamman-Rich disease in 1944. Another name in the clinical literature is accelerated interstitial pneumonia, idiopathic acute respiratory distress syndrome (idiopathic ARDS), and the organizing stage of diffuse alveolar damage. Acute interstitial pneumonia differs from chronic interstitial pneumonia by clinical and pathologic features. Clinically, this disease is characterized by a sudden onset and a rapid course, and reversible disease. Method and Purpose: Five cases of pathologically proven acute interstitial pneumonia were retrospectively studied to define the clinical, radiologic, and pathologic features. Results: 1) The five cases ranged in age from 31 to 77 years old. The onset of illness was acute in all patients, it began with viral-like prodrome 6~40 days prior to shortness of breath, and respiratory failure eventually developed in all patients. In 2 cases, generalized skin rash was accompanied with flu-like symptoms. Etiologic agent could not be identified in any case. 2) All patients had leukocytosis and severe hypoxemia. Pulmonary function test of 3 available cases shows restrictive ventilatory defect, and one survived patient(case 5) has a complete improvement of pulmonary function after dismissal. 3) Diffuse bilateral chest infiltrates were present radiologically. Theses were the ground-glass, consolidation, and reticular densities without honeycomb fibrosis in all patients. The pathologic abnormalities were the presence of increased numbers of macrophages and the formation of hyaline membranes within alveolar spaces. There was also interstitial thickening with edema, proliferation of immature fibroblast, and hyperplasia of type II pneumocyte. In the survived patient(case5), pathologic findings were relatively early stage of acute interstitial pneumonia, such as hyaline membrane with mild interstitial fibrosis. 4) Of the 5 patients, four patients died of respiratory failure 14~90 days after onset of first symptom, and one survived and recovered in symptoms, chest X ray, and pulmonary function test Conclusion: These results emphasize that acute interstitial pneumonia is clinically, radiologically, and pathologically distinct form of interstitial pneumonia and should be separated from the group of chronic interstitial pneumonia. Further studies will be needed to evaluate the pathogenesis and the treatment of acute interstitial pneumonia.

• Journal of Ginseng Research
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• v.27 no.3
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• pp.103-109
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• 2003

We investigated the effect of ginseng total saponin (GTS) on the regeneration process of experimentally crush injured rat sciatic nerves. The bilateral sciatic nerves of fifty adult male Sprague-Dawley rats were compressed surgically with a straight hemostat for 30 seconds with 1 mm width. Twenty rats were divided into four groups to test the dose-dependent effect of GTS (0, 50, 100, or 150 mg/kg, i.p.). Saline for vehicle control group or GTS dissolved in saline was administerd for three weeks. After that period of time, the numbers of total myelinated axon and degenerated myelin in the sciatic nerves of bilateral legs were examined and analyzed using image analysis system to confirm a morphological effect of GTS. We found that the most effective concentration of GTS for the regeneration of damaged sciatic nerve was 150 mg/kg. In another set of experiment, thirty rats were divided into two groups as saline-treated vehicle group and GTS-treated group (150 mg/kg, i.p.) for three weeks. Every week we examined the numbers of total myelinated axon and degenerated myelin in the sciatic nerves of bilateral legs using image analysis system to evaluate the effect of GTS on injured nerves. We found that the regeneration of damaged sciatic nerves was facilitated in GTS-treated group compared to saline-treated group until two weeks. However, after that period of time we could not observe the significant difference between saline-treated group and GTS-treated group. These results suggest that GTS is a useful adjuvant therapy for the regeneration of the peripheral nerve injury in short period of treatment.

• The korean journal of orthodontics
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• v.27 no.3 s.62
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• pp.391-399
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• 1997

Rapid palatal expansion(RPE) is a method of inducing the new bone formation in the palate by separation of the midpalatal suture, which can be done conveniently by placing heavy force across the maxillary dental arch. This experiment was undertaken to examine the histologic changes after RPE and during retention period. Four young adult dogs(a control dog, three experimental dogs) aged 4 to 6 months old were used for this experiment. Expansion screw($Hyrax^{\circledR}$, Dentarum Inc.) was delevered to the palate and fumed 180 degrees every morning and evening for 8 days, giving a total expansion of 7.2mm. A control dog was sacrified at the starting point of this study without any treatment and three experimental dogs were sacrified after RPE, 14-day retention, and 28-day retention in each. Thereafter, those samples were observed with hematoxylin-eosin(H-E) stain, ground section(Villanueva stain), alkaline phosphatase(ALP) stain, tartrate-resistant acid phosphatase(TRA) stain. The results were as followings: 1. After RPE, collagen fiber bundles were stretched along the midpalatal suture and few osteoblasts were flattened-inactive state and also, a little osteoid tissues was observed. Few multinucleated osteoclasts which had TRAP-positive activity in their cytoplasm were seen in horizontal section, whereas a few osteoclasts were seen in frontal section, especially in the nasal floor side of palatal bone. 2. After 14-day retention, collagen fiber bundles were stretched along the midpalatal suture and few osteoblasts which had ALP-positive activity in their cytoplasm were seen. Few multinucleated osteoclasts which had TRAP-positive activity in their cytoplasm were seen in horizontal section, whereas a few osteoclasts were seen in frontal section, especially in the nasal floor side of palatal bone. 3. After 28-day retention, collagen fiber bundles were arranged like those of control dog and osteoblasts which showed a lot of immature bone formation were cuboidal shape and exhibited ALP-positive activity in their cytoplasm. Few multinucleated osteoclasts which had TRAP-positive activity in their cytoplasm were seen in horizontal section, whereas a few osteoclasts were seen in frontal section, especially in the nasal floor side of palatal bone. According to the above results, the new bone formation after rapid palatal expansion was examined after 14-day retention and significantly increased after 28-day retention.

• Journal of Sericultural and Entomological Science
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• v.36 no.2
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• pp.138-146
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• 1994

The structural characteristics of Antheraea yamamai and Antheraea pernyi silk were investigated by using x-ray diffraction method, IR spectroscopy and polarizing microscopy. The amino acid composition, fiber density, thermal decomposition temperature and glass transition temperature were also measured for relating these physical properties to the structure in comparison with those of Bombyx mori silk fiber. There was no significant structural difference between A. yamamai and A. pernyi silk fiber on an examination of x-ray diffraction curve and IR spectrum. Both of these wild silk fibers showed double diffraction peaks at the Bragg angle 2Θ16.7˚ and 20.5˚by x-ray diffraction analysis as well as IR absorption peaks for the bending vibration of specific groups related to ala-ala amino acid sequence. On the other hand, the x-ray diffraction curve and IR spectrum of Bombyx mori silk fiber are different from those of wild silk fibers, indicating different crystal structure as well as amino acid sequences. It showed under the polarizing microscope examination that the birefringence and optical orientation factor of wild silk fibers are much lower than those of B. mori silk. Also, the surface of degummed wild silk fibers was characterized by the longitudinal stripes of microfibrils in the direction of fiber axies. The amino acid composition, which is strongly related to the fine structure and properties, was not significantly different between these two wild silk fibers. However, the alanine content was somewhat less and polar amino acid content more for A. yamamai. As a result of fiber density measurement, the specific gravities of B. mori, A. pernyi and A. yamamai were 1.355~1.356, 1.308~1.311, 1.265~1.301g/㎤ in the order, respectively. The calculated crystallinity(%) was 64% for B. mori and 51~52% for wild silk fibers, which showed same trend by IR method in spite of somewhat higher value. The thermal decomposition behaviour was examined by DSC and TGA, showing that the degradation temperature was in the order of B mori, A. prernyi and A. yamamai at around 350$^{\circ}C$. It was also observed by TGA that the decomposition seems to proceed step by step according to their specific regions in the fiber structure, resulting the difference in their thermal stabilities. The glass transition temperature was turned out to be 220$^{\circ}C$ for B. mori, 240$^{\circ}C$ A. yamamai and 255$^{\circ}C$ A. pernyi by the dynamic mechanical analysis. It is expected that the chemical properties are affected by the dynamic mechanical behavior in accordance with their structural characters.

• Radiation Oncology Journal
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• v.15 no.1
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• pp.37-47
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• 1997

Purpose : To investigate ultrastructural changes of the mouse lung induced by whole lung gamma irradiation and to evaluate the effect of prophylactic administration of steroid against acute lung injury. Materials and Methods :. One hundred and twenty ICR mice were used and whole lung was irradiated with telecobalt machine. Whole lung doses were 8 and 12Gy, and 10mg of methyl prednisolone was administrated intraperitoneally for two and four weeks. At the end of the observation period, mice were sacrificed by cervical dislocation. The lungs were removed and fixed inflated. Histopathological examination of acute radiation injuries were Performed by light microscopic and transmission electron microscopic examination. Results : Control group with BGy is characterized by damage to the type I Pneumocyte and the endothelial cell of the capillary. edema of alveolar wall and interstitium. and fibroblast proliferation. Control group with 120y is characterized by more severe degree of type 1 pneumocyte damage and more prominant inflammatory cell infiltration. Destructed cell debris within the alveolar space were also noted After steroid administration, 8Gy experimental group showed decreased degree of inflammatory reactions but fibroblast proliferation and basal lamina damages were unchanged. Experimental group with 12Gy showed lesser degree of inflammatory reactions similar to changes of 8Gy experimental group. Conclusion : These studies suggest that the degree of interstitial edema and inflammatory changes were related to radiation dose but Proliferation of the fibroblast and structural changes of basal lamina were not related to radialion dose. Experimental administration of steroid for 2 to 4 weeks after whole lung irradiation suggest that steroid can suppress alveolar and endothelial damages induced by whole lung irradiation but Proliferation of the fibroblast and structural changes of basal lamina were not related to administration of steroid.

• The korean journal of orthodontics
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• v.30 no.3 s.80
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• pp.317-333
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• 2000

The purpose of this study was to determine the proliferative activity of the osteoblasts and fibroblasts in the midpalatal area and to investigate the adjacent periodontal tissues of individual tooth following rapid expansion of the palate. Ten young adult dogs, aged approximately ten months, were used in the experiment. The experimental design was consisted of 1 week expansion group(Group E1, 3 dogs), 2 week expansion group(Group E2, 3 dogs), 2 week expansion and 2 week retention group(Group E3, 3 dogs), and control group(Group C, 1 dog). For each group, expansion screw was activated one time per day(1/4 turn;$90^{\circ}$) following Hyrax-screw application. The experimental animals in each group were sacrificed at 1, 2 and 4 weeks following palatal expansion. Maxillary tissue blocks were obtained and prepared ior the histomorphologic and immunohistochemical studies. Light mcroscope, polarizing microscope, and soft X-ray apparatus were used in this study, and following results were obtained. 1. In polarizing microscopic study, the expansion groups(E1 & E2) showed blue color representing bone resorption and new bone formation in midpalatal suture area. E3 groups skewed less blue color compared to the E1 and E2 group. But yellow color increased by calcification in the E3 groups. 2. Immunohistochemical study revealed that positive responses of the osteoblasts to PCNA and undifferentiated fibroblasts to EGF in E1 group were somewhat increased. Positive response to PCNA and EGF were increased in fibroblasts and the osteoblasts forming new bone in E2 group. In E3 group, the positive response cell concentrated the periphery of edge of palatal process in both PCNA and EGF. 3. Throughout the expansion period(E1 & E2), light microscopic study showed the edges of the extensive resorption and new palatal processes, indicating bone remodeling within the suture. E3 group exhibited less remodeling of midpalatal suture area. E2 group and E3 group showed cementum formation and resorption at the apex of 3rd premolar and 1st molar E3 group exhibited extensive hyalinized zone on the cervical portion of buccal side of 1st molar. 4. Soft X-ray analysis of E1 group showed hypomineralized defect and microfractures in various parts of the suture areas when compared with control animals. There was no significant difference in the degree of mineralization in the midpalatal suture region between the C and E3 groups. Tooth axis showed tipping of 3rd premolar and 1st molar in the E2 group and E3 group. Based upon these experimental results, it is concluded that the undifferentiated mesenchymal cells always presented in midpalatal suture area following RPE. Differentiated osteoblasts and fibroblasts possess proliferating cellular activity until the 2 week retention period. The posterior teeth are tend to tip buccally as RPE force applied. Retention group exhibited irreversible response with severe hyalinized zone on the buccal surface of the first molar.