• Applied Microscopy
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• v.26 no.2
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• pp.123-136
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• 1996

To investigate the effect of aflatoxin $B_1$, on survival rate and ultrastructure of liver during chick embryogenesis electron microscopic methods were used. After injection of aflatoxin $B_1$ into the yolk, ultrastructural changes in the liver of chicken embryo were observed. The results were as followed. 1. 12-day old chicken embryos were treated with single injection of aflatoxin $B_1$ with the dose of $0.0005{\mu}g,\;0.005{\mu}g,\;0.05{\mu}g,\;0.5{\mu}g,\;2.5{\mu}g,\;5.0{\mu}g$ each. Chicken embryos treated with the dose of $0.5{\mu}g$ of aflatoxin $B_1$ had survival rate of 22%. The embryos treated with $2.5{\mu}g$ of aflatoxin $B_1$ hardly survived. 2. Chicken embryos treated with $0.05{\mu}g$ of afatoxin $B_1$ had hatched in 30%, but once hatched, they all survived. 3. After administration of $0.05{\mu}g$ of aflatoxin $B_1$ into the 12-day old chicken embryo, the electron microscopic studies were examined during development stages. The nuclei of hapatocytes became irregularly shaped and the structures of endoplasmic reticulum were changed to spherical types at 20-day old chicken embryo. Also, mitochondria became to be dilated and severe fibrosis was induced in the cytoplasm. However, the hepatocytes became almost normal in 30-day old young chicken.

• Journal of the Korea Institute of Building Construction
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• v.11 no.2
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• pp.171-180
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• 2011

As high-rise and irregularly shaped building structures have become a trend at home and abroad, BIM technology is now being developed and accepted widely. However, the BIM data and information generated in the design phase cannot be actively reutilized in the construction stage. This is because the major interests of construction companies include working process and cost estimation, while there is not usually enough BIM data created to support these activities. In order to resolve this issue, we need to set up BIM modeling guides that make it possible to extract correct quantity take-off from BIM data. Quality checks are also necessary to ensure that the resulting BIM data is correct. This study suggests ways of securing BIM quality for correct quantity take-off, which is critical for BIM technology applied to the building construction process and its cost estimation.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.17 no.4
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• pp.337-349
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• 1995

Periosteum in general is described as a specialized fibrous membrane of mesenchymal origin consisting of two basis layers : outer fibrous layer consists of irregularly arranged dense connective-tissue with fibroblasts, and inner osteogenic or cambial layer is composed of more loosely arranged fibers, greater vascularity and flatted spindle-shaped pre-osteoblasts. This periosteum may serve in controlling bone growth, especially mandibular growth has been emphasized. But, the periosteum enwrapping the facial skeleton have been studied for many years leaving a controversy in opinion regarding the function of these structures. We evaluated the bone formation activity of te periosteum in allogeneic bone grafts which bones are made of freeze-dried preparation preoperatively. We made the calvarial bone defects, 5 ${\times}$ 7mm sized, amd grafted with allogeneic bone in rats, which a half of specimens has dissected the overlying periosteum and a rest intacted. After bone grafting, we evaluated the capacity ofbone formation of periosteum, 1, 2, 4, 6, 8 weeks postoperatively. There are subtle differences of bone formation during early healing period after demineralized allogeneic bone grafting between control groups with periosteum and experimental groups without periosteum.

• Journal of Biomedical Engineering Research
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• v.34 no.2
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• pp.55-62
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• 2013

Wrist joints consist of irregularly shaped carpal bones and other complicated structures. Thus, evaluating the motion of a wrist joint is a challenging task. In this study, we used an infrared camera to perform a kinematic analysis of a dart-throwing motion. We measured the difference between the movement of a normal wrist and constrained wrist (wrist with a wrist glove) in the dart-throwing motion with thirty six healthy participants. We measured the ulna flexion - radial extension motion using the attached passive marker and analyzed it using Polygon software and SPSS. The pitch and yaw motions with a glove was bigger than the ones without a glove by 20 and 15 degrees, respectively. On the other hand, the roll motion without a glove was bigger than the one with a glove by 7 degree. Wilcoxon signed rank test (p<0.05) confirmed that there are significant differences between the motion with and without a glove. It was found that the magnitude of the pitch and yaw motion with a constrained wrist joint toward radial extension in dart-throwing motion is smaller than the one with a normal wrist joint. However, a normal wrist joint showed a bigger movement in the roll direction.

• Applied Chemistry for Engineering
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• v.32 no.1
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• pp.91-96
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• 2021

This study was conducted to improve the operating conditions of an adsorption tower filled with potassium impregnated activated carbon for high hydrogen sulfide capture capacity. Heat treatment modified the surface properties of activated carbon, and ultimately determined its adsorption capacity. The activated carbon doped with potassium showed 57 times more adsorption at room temperature than that of using the raw adsorbent. It is believed that uniform pore formation and strong bonding of the potassium on the surface of carbon contributed to the chemical and physical absorption of hydrogen sulfide. The SEM analysis on the surface structure of various commercial carbons showed that the modification of surface properties through the heat treatment generated the destruction of pore structures resulted in the decrease of the absorption performance. The pressure drop across the activated carbon bed was closely related with the grain size and shape. The optimum size of irregularly shaped activated carbon granules was 2~4 mesh indicating economical feasibility.

• Applied Microscopy
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• v.15 no.1
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• pp.31-58
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• 1985

The morphological study on different types of cells of reproductive organ including spermatogenesis in the adult planaria was performed to observe their cytochemical and ultrastructural characteristics. 1. Spermatogenesis The circular luminated material appears immediately inside the nuclear envelope of early spermatid and is found also in the nucleus of sperm, but typical acrosomal structures cannot be observed. Approximately ten of small-sized mitochondria occur around the nucleus in the transitional phase from primary spermatocyte to secondary spermatocyte, but in sperm a long mitochondrion is closely associated with nucleus, parellel to long axis of it. The sperm has a relatively long head connected with two tails via hollow neck. 2. Reproductive organ The penis bulb and the bursa stalk were observed. (1) Penis bulb The cells constituted penis bulb are classified into six types on the basis of ultrastructure of the cells and cytochemistry of the cytoplasmic granules. 1) A-type cells: These cells exhibiting low electron density are mainly occupied by large nucleus. These cells possess two different types of granules: highly electron-dense round granules with an average size of $0.9{\mu}m$, and electron-dense granules exhibit PAS-positive reaction. 2) B-type cells contain PAS-positive granules with the size of about $0.4{\mu}m$. They are rich in free ribosomes and mitochondria. 3) C-type cells are found to be dark cells due to high electron-density. These cells are largely occupied by large nucleus. 4) D-type cells: These cells are seen as light cells which have poorly developed cell organelles. 5) E-type tells: These cells contain a large number of glycogen granules which occupy most of cell. 6) F-type cells: These arc parietal epidermal cells surrounding the genital antrum. These cells are characterized by their finger-like shapes and the presence of a number of electron-dense, irregularly-shaped structures inside cells. The relatively large electron-lucent granules can be also found. The F-type cells possess numerous microvilli on their free surfaces. (2) Bursa stalk The cells constituted bursa stalk are classified into 3 types on the basis of cell shapes and presences of electron-dense or electron-lucent granules. 7) G-type cells with a long cytoplasmic process. They have large nuclei and poorly developed cell organelles. 8) H-type cells: These cells are characterized by the presence of a long cytoplasmic process and relatively highly electron-dense cytoplasmic profile. They have poorly developed cell organelles. 9) I-type cells contain large electron-lucent granules which exhibit negative reactions with three kinds of cytochemical staining methods used in this experiment. The fine electron-dense structures can be found inside these granules.

• Progress in Medical Physics
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• v.16 no.1
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• pp.24-31
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• 2005

The stereotactic radiosurgery (SRS) describes a method of delivering a high dose of radiation to a small tar-get volume in the brain, generally in a single fraction, while the dose delivered to the surrounding normal tissue should be minimized. To perform automatic plan of the SRS, a new method of multi-isocenter/shot linear accelerator (linac) and gamma knife (GK) radiosurgery treatment plan was developed, based on a physical lattice structure in target. The optimal radiosurgical plan had been constructed by many beam parameters in a linear accelerator or gamma knife-based radiation therapy. In this work, an isocenter/shot was modeled as a sphere, which is equal to the circular collimator/helmet hole size because the dimension of the 50% isodose level in the dose profile is similar to its size. In a computer-aided system, it accomplished first an automatic arrangement of multi-isocenter/shot considering two parameters such as positions and collimator/helmet sizes for each isocenter/shot. Simultaneously, an irregularly shaped target was approximated by cubic structures through computation of voxel units. The treatment planning method by the technique was evaluated as a dose distribution by dose volume histograms, dose conformity, and dose homogeneity to targets. For irregularly shaped targets, the new method performed optimal multi-isocenter packing, and it only took a few seconds in a computer-aided system. The targets were included in a more than 50% isodose curve. The dose conformity was ordinarily acceptable levels and the dose homogeneity was always less than 2.0, satisfying for various targets referred to Radiation Therapy Oncology Group (RTOG) SRS criteria. In conclusion, this approach by physical lattice structure could be a useful radiosurgical plan without restrictions in the various tumor shapes and the different modality techniques such as linac and GK for SRS.

• Applied Microscopy
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• v.21 no.2
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• pp.76-95
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• 1991

A single injection of cadmium chloride (3.75 mg/kg) was made into the peritoneal cavities of albino rats. The cortices of kidney were obtained from the experimental animals at 3 hr., 6 hr., 12 hr., 24 hr. and 36 hr. after administration of cadmium chloride, respectively. The specimens of each experimental animal were prefixed in 2% glutaraldehyde-4% paraformaldehyde solution for $2{\sim}4$ hours, and these specimens were post-fixed in 1% osmic acid. After fixation, the specimens were dehydrated with alcohol and acetate and embedded in Epon 812. Ultrathin sections, $600{\sim}800{\AA}$ thickness were made and stained with uranyl acetate and lead citrate. And all the preparations were observed with Hitachi-600 transmission electron microscope. The results obtained were as follows: 1. The main changes in ultrastructures of the glomeruli observed at 3 hr. after cadmium chloride administration include loss of filtration slit and fenestrae of capillary endothelium that was resulted from thickings of the basal lamina and fusion of pedicels of the podocytes. At 12 hr. after cadmium chloride administration the Bowman's capsules were mostly filled with abnormally thickened and fused pedicels. After 24 hr. however, the only recognized change was loss of fenestrae of the capillary endothelium. And the ultrastructure of the glomeruli were almost normal in 36 hr. after cadmium chloride treatment. 2. At 3 hr. after treatment with cadmium chloride, in the renal tubular cells the vesicles and vacuoles increased in number at the apical portion, of the tubular epithelial cells, the basal infoldings were reduced and the basal lamina was thickened. After 12 hr., a number of phagosomes appeared at the apical portion and the cisternae of rough endoplasmic reticulum were swollen. At 24 hr. after cadmium chloride administration irregularly shaped mitochondria were observed in the apical area, and mitochondria with swollen cristae were found at the basal portion. And after 36 hr. The ultrastructures of the epithelial cells appeared almost normal except for a moderate increase in the number of vesicles and vacuoles. Consequently it is suggested that in albino rats, cadmium chloride induces acute reversible degenerative changes in the glomeruli as well as in the epithelial cells of the proximal convoluted tubules.

• Radiation Oncology Journal
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• v.18 no.2
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• pp.150-156
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• 2000

Purpose : Stereotactic radiation therapy (SRT) can deliver highly focused radiation to a small and spherical target lesion with very high degree of mechanical accuracy. For non-spherical and large lesions, however, inclusion of the neighboring normal structures within the high dose radiation volume is inevitable in SRT This is to report the beam shaping using the partial closure of the independent jaw in SRT and the verification of dose calculation and the dose display using a home-made soft ware. Materials and Methods : Authors adopted the idea to partially close one or more independent collimator jaw(5) in addition to the circular collimator cones to shield the neighboring normal structures while keeping the target lesion within the radiation beam field at all angles along the arc trajectory. The output factors (OF's) and the tissue-maximum ratios (TMR's) were measured using the micro ion chamber in the water phantom dosimetry system, and were compared with the theoretical calculations. A film dosimetry procedure was peformed to obtain the depth dose profiles at 5 cm, and they were also compared with the theoretical calculations, where the radiation dose would depend on the actual area of irradiation. Authors incorporated this algorithm into the home-made SRT software for the isodose calculation and display, and was tried on an example case with single brain metastasis. The dose-volume histograms (DVH's) of the planning target volume (PTV) and the normal brain derived by the control plan were reciprocally compared with those derived by the plan using the same arc arrangement plus the independent collimator jaw closure. Results : When using 5.0 cm diameter collimator, the measurements of the OF's and the TMR's with one independent jaw set at 30 mm (unblocked), 15.5 mm, 8.6 mm, and 0 mm from th central beam axis showed good correlation to the theoretical calculation within 0.5% and 0.3% error range. The dose profiles at 5 cm depth obtained by the film dosimetry also showed very good correlation to the theoretical calculations. The isodose profiles obtained on the home-made software demonstrated a slightly more conformal dose distribution around the target lesion by using the independent jaw closure, where the DVH's of the PTV were almost equivalent on the two plans, while the DVH's for the normal brain showed that less volume of the normal brain receiving high radiation dose by using this modification than the control plan employing the circular collimator cone only. Conclusions : With the beam shaping modification using the independent jaw closure, authors have realized wider clinical application of SRT with more conformal dose planning. Authors believe that SRT, with beam shaping ideas and efforts, should no longer be limited to the small spherical lesions, but be more widely applied to rather irregularly shaped tumors in the intracranial and the head and neck regions.