• Clinical and Experimental Reproductive Medicine
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• v.30 no.3
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• pp.241-248
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• 2003

Objective: The purpose of this study was to evaluate the survival rate of vitrified blastocyst according to the freezing vessels, equilibration time in cryoprotectant and artificial dehydration method. Methods: Human blastocysts were vitrified after loading onto the plastic straw, open-pulled straw (OPS), electron microscopy grid (EM grid) for 1.5 min or 3 min. They also were directly plunged into LN2 within 30sec. For artificial shrinkage of blastocysts, 36 gauge fine needle was pushed at the cellular junction of the trophectoderm into the blstocoele cavity until it shrank without damage of inner cell mass. Results: The survival rate of vitrified blastocysts on plastic straw, OPS, EM grid as freezing vessels were 26.7, 13.0 and 60.5%, respectively. The survival rate of EM grid was significantly higher than that of plastic straw and OPS (p<0.05). For 1.5 min equilibrium, the survival rates of early blastocyst (EB), middle blastocyst (MB) and late blastocyst (LB) were 64.4, 81.0, and 20.0% respectively. For 3 min equilibrium, the survival rates of EB, MB, and LB were 69.9, 50.0 and 57.5% respectively. The survival rates of EB and MB were significantly higher than that of LB in 1.5 min equilibrium group (p<0.05), however, the significance was not observed in 3 min equilibrium groups. In cytoplasmic shrinkage before vitrification, the survival rates of EB, MB and LB were 92.9, 100 and 75.9% respectively. The survival rate of MB was significantly higher than that of LB (p<0.05). The survival rates of vitrified blastocysts by artificial dehydration and slow-frozen blastocysts were not significantly different as 88.9 and 66.7%, respectively. Conclusion: This study showed that the vitrification of human blastocysts using EM grid and artificial dehydration is an effective method. Therefore, these methods would be an useful techniques for blastocyst cryopreservation.

• Restorative Dentistry and Endodontics
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• v.33 no.2
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• pp.83-89
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• 2008

The purpose of this study was to evaluate the effect of the polymerization shrinkage and modulus of elasticity of composites on the cusp deflection of class V restoration in premolars. The sixteen extracted upper premolars were divided into 2 groups with similar size. The amounts of cuspal deflection were measured in Class V cavities restored with a flowable composite (Filtek flow) or a universal hybrid composite (Z-250). The bonded interfaces of the sectioned specimens were observed using a scanning electron microscopy (SEM). The polymerization shrinkage and modulus of elasticity of the composites were measured to find out the effect of physical properties of composite resins on the cuspal deflection. The results were as follows. 1. The amounts of cuspal deflection restored with Filtek flow or Z-250 were $2.18\;{\pm}\;0.92{\mu}m$ and $2.95\;{\pm}\;1.13\;{\mu}m$, respectively. Filtek flow showed less cuspal deflection but there was no statistically significant difference (p > 0.05). 2. The two specimens in each group showed gap at the inner portion of the cavity. 3. The polymerization shrinkages of Filtek flow and Z-250 were 4.41% and 2.23% respectively, and the flexural modulus of elasticity of cured Filtek flow (7.77 GPa) was much lower than that of Z-250 (17.43 GPa). 4. The cuspal deflection depends not only on the polymerization shrinkage but also on the modulus of elasticity of composites.

• Applied Microscopy
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• v.17 no.1
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• pp.131-160
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• 1987

Anatomical features of the renal papilla and pelvis and ultrastructures of the epithelium covering these areas in four species of mammals were studied by means of light, scanning and transmission electron microscopy. In terms of the morphology of mammalian kidney types distinguished by Sperber(1944), Pfeiffer(1968) and Schmidt-Nielsen(1977), the kidneys of animal species used in this experiment were; 1) the mouse kidney with the fornix between a long conical papilla and the funnel-shaped pelvis, 2) the guinea pig kidney with the peripelvic column and pelvic pouch between a short conical papilla and the funnel-shaped pelvis, 3) the dog kidney with the peripelvic column and pelvic pouch between the crest-shaped papilla and the funnel-shaped pelvis, and 4) the cattle kidney which is divided into multiple renculi with minor and major calyces and pelvis. The renal papilla was lined with the simple or pseudostratified columnar epithelium which covered the inner zone of the renal medulla. The epithelial cells with numerous short microvilli on the surface contained a few organelles. In the mouse, the fornix was lined with one to two cell-layered cuboidal epithelium which covered the outer zone of the renal medulla and a part of the cortex. The epithelial cells of the fornix with numerous short microvilli or microridges on the surface had well-developed organelles. In the guinea pig, the peripelvic column was lined with the simple cuboidal or low columnar epithelium which covered the outer zone of the renal medulla. The epithelial cells with numerous short microvilli on the surface contained well-developed organelles. The pelvic pouch was lined with the pseudostratified columnar epithelium which was composed of four kinds of cells; the secretory cell with small electron-dense granules (310 nm), the secretory cell with large granules (720 nm) showing various electron densities, the mitochondria-rich cell with a single cilium, and the basal cell. Pelves of the mouse and guinea pig, peripelvic column, pelvic pouch and pelvis of the dog, and minor and major calyces and pelvis of the cattle were lined with the transitional epithelium. The fusiform vesicles in the superficial cells of the epithelium were highly developed in the dog, relatively well developed in the mouse and guinea pig, and poorly developed in the cattle. From the above findings, it is suggested that the transport of solutes and water of the urine in the pelvic cavity can take place through the epithelia covering the renal papilla and fornix of the mouse, papilla and peripelvic column of the guinea pig, and papillae of the dog and the cattle. And specialized cell types in the epithelium of the guinea pig pelvic pouch, two kinds of secretory cells and mitochondria-rich cell with a single cilium, could have peculiar functions in the renal pelvis, respectively.

• Progress in Medical Physics
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• v.13 no.2
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• pp.55-61
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• 2002

In this work, EPM (effective point of measurement) of parallel plate ionization chamber with three different spacing were investigated. If the plate separation is less than 2 mm one generally assumes that the effective point of measurement is just behind the front window of the parallel plate ionization chamber. For chamber with relatively large separation, such as the ones used for very accurate exposure measurements, this assumption breaks down and the EPM depends on plate separation and thickness of the front window. For parallel plate chambers, conventional theoretical analyses suggest that the EPM is the inner front wall and that it shifts towards the geometric centre of the chamber as the plate separation increases. The PP-IC (parallel plate ionization chamber) is fabricated using acrylic plate for the chamber medium and printed circuit board for electrical configuration. The various sizes of the sensitive volumes designed so far are 0.9, 1.9, and 3.1 cc. The gap between two electrodes ranges from 3, 6, and 10mm. Also the charge-to-voltage converter is designed to collect the electrons produced in the ionization chamber cavity. As the result of our experiment, the EPM shift was within 0.6 mm in photon beams and 0.4 mm to 2.5 mm in electron beams for the plate separation of 6 mm and 10 mm. EPM shifts towards the geometric center of the chamber as the plate separation increases.

• Applied Microscopy
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• v.32 no.3
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• pp.231-246
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• 2002

This study was carried out to investigate the effect of squalene (SQ) on the mouse hepatotoxicity induced by cadmium. ICR male mouse weighting about 30 gm were injected $CdCl_2$ (5.0 mg/kg) and SQ (180 mg/kg) into intraperitoneal. At the 1, 2, 3, 4, 5, 6, 7 days, livers were treated with superoxide dismutase (SOD) activity and transmission electron microscopical method and then observed with electron microscope. The results obtained were summarized as follows: SOD activity in the liver, Group A was higher than in normal. Group B was lower than in Group A. In the histological observation, nucleus of Group A showed irregular shape. Inner cavity of mitochondria swellen and development of cristae weakened. Swelling of Lamellae of rough endoplasmic reticulum (RER) showed. Nucleus of group B showed normal shape. Typical lamellae of RER were observed. These results described above treatment of SQ decreased the hepatotoxicity of the $CdCl_2$ and SOD activity in the mouse liver, and then it suggests SQ may be effective for the recovery of hepatic cell.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.1
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• pp.139-145
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• 2006

Ranula is a mucocele which occurs at the mouth floor and is mostly related to sublingual gland. In other words ranula is definded as a pseudocyst which occurs as the secretion duct of sublingual gland is destructed there as the saliva from the secretion duct flows out and retention in the soft tissue. The cause of ranula is destruction or obstruction of the duct. The clinical findings of ranula is a painless, unilateral bluish transparent swelling around the frenum and shows fluctuation when palpated. Histological finding represent a formation of cavity inside the connective tissue, but a pseudo-cyst can be seen which the wall of the cyst is composed of granulation tissue rather than epithelial cells. The first treatment of ranula can be considered as marsupialization. which induces the inner wall of the Ranula to be a part of oral mucosa. This case report shows a treatment of marsupialization with gauze packing in a young patient representing a clinical finding of characteristic ranula.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.2
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• pp.116-124
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• 2008

Statement of the problem: Implant systems result in gaps and cavities between implant and abutment that can act as a trap for bacteria and thus possibly cause inflammatory reactions in the peri-implant soft tissues. Purpose: Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, Treponema denticola, and Aggregatibacter actinomycetemcomitans, related to implant-abutment interface microleakage. Material and methods: Samples were taken from 27 subjects with sterilized paper points and were transported in $1{\times}PBS$. The detection of periodontopathogens were performed by polymerase chain reaction with species-specific primers based on 16S rDNA. Results: Our data showed that the detection rate of P. gingivalis and P. intermedia in implant fixture was 59% and 82% in patients respectively. Detection rate of P. gingivalis and P. intermedia in implant crevice was 44% and 82% in patients. Detection rate of P. gingivalis and P. intermedias in tongue was 82% and 82% in patients. Conclusion: Current implant systems cannot safely prevent microbial leakage and bacterial colonization of the inner part of the implant.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.7
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• pp.2919-2924
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• 2011

The automatic drawer is used to absorb the movement shock and adjust its velocity when it opens and closes. The tube in shock-absorber is the cylindrical case which surrounds its parts and is made of acetal. The purpose of this study is to determine the quality stability of the tube in the shock-absorber in injection molding process. The tube which had been manufactured in the process with 4 cavity cooling unit was used. In this study, the analysis and test are carried out to determine its quality stability. Which are the quality analysis with numerical simulation and performance tests of the tube compared with one of foreign make. It is calculated that the injection press is 87.6 MPa and the deflections in X, Y, Z directions are ranged in 0.07~1.00 mm. When the researched tube is compared with the foreign made tube, the maximum bending compressive load is 231 kgf higher, average axial compressive load is 0.05 kgf higher, and the roughness(Ra) on the inner surface is $0.02\;{\mu}m$. lower. In the result, it is known that the quality of researched tube in injection mold process is stable and its performance is superior.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.8-16
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• 1998

Sexual maturation and reproductive cycle of the goldeye rockfish, Sebastes thompsoni were investigated under photomicroscopy. Samples were collected monthly in the coastal water of Samcheonpo ($34^{\circ}55'N$ ), Korea from November 1995 to October 1996, The ovary consists of several ovarian lamellae originated from ovarian outer membrane. Oogonia which are originated from the inner surface of the ovarian lamella protrude to the ovarian cavity in oocyte stage, and they ave suspended by the egg stalk. The testis is seminiferous tubule type in internal structure. Seminiferous tubule consists of many testicular cysts which contain numerous germ cells in same developmental stage. Biological minimum size of female and male were 19.5 cm and 21.5 cm in total length, respectively. Gonadosomatic index (GSI) of female was the highest (9.56) in March and the lowest (0.15) in August. GSI of male was the highest (0.25) in February and the lowest (0.04) in July. Reproductive cycle was classified into the following successive stages: in female, growing (October and November), maturation ( $December\~February$), gestation (March), parturition and recovery ($April\~June$) and resting ($July\~September$), and in male, growing ($September\~November$), maturation ( December and January), ripe and copulation ( February and March) and degeneration and resting ($April\~August$).

• Land and Housing Review
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• v.12 no.1
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• pp.129-137
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• 2021

External shading devices are well known solar control devices that can help reduce the cooling load of commercial buildings. For this study, experiments were conducted to examine the feasibility of shading devices in reducing both the cooling and heating loads. The influence of sky radiant cooling during winter was verified for the external shading device, internal roller blind, and window. Results can be summarized as follows. The temperature difference between the inner and outer surfaces of the window with the external shading device was 11.8℃ compared to 14.6℃ for one without the external shading device. This 2.8℃ difference was due to heat exchange by sky radiation when the surface temperature of the shading device was lower than the ambient outdoor air temperature. The roller blind resulted in a lower temperature of 0.8℃ compared to the average temperature of the window's air cavity. This was due to heat exchange by sky radiation of the roller blind surfaces. Without shading devices, the outside surface temperature of the window is about 3℃ higher. The study also found that when external shading devices were installed on both the southwest and southeast sides, the outside surface temperature of the windows were lower on the southwest side than the southeast side.