• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.1
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• pp.39-46
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• 2010

To assess the stress distribution of implant prosthesis induced by intentional misfit using photoelastic model. Stress was measured at the surrounding bone after applying vertical load to the implant. Three implants were placed in each of three photoelastic resin blocks. No misfits were used for the control group, while for the experimental group $100{\mu}m$ misfit after cutting the crown was used. The photoelastic stress analysis was performed. In control group, stress concentration was not shown when the load was not applied, whereas stress concentration was shown only in the loaded part even when load was applied and the stress was distributed in anterior-posterior direction when applying a load in the middle. When intentional misfits were given, stress around the fixture was incurred when tightening the screw even if load was not applied. If the load was applied, stress was concentrated around the implants including areas where the load was applied. In particular, the prosthesis made of UCLA showed more stress concentration as compared with a conical abutment. In the UCLA case, concentration was shown from the apex following through the axis to the cervical area. Prosthesis with misfit makes the stress concentrated though the load was not applied and it induces even more severe stress concentration when the load was applied. This founding demonstrates the importance of the correct prosthesis production.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.1
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• pp.30-38
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• 2008

Dental pulp cells are assumed to possess the capacity to elaborate both bone and dentin matrix under the pathological conditions following tooth injury. The purpose of this study is to examine the effects of mineral trioxide aggregate (MTA) on various gene expression regarding dentinogenesis and cell viability assay in cultured primary human dental pulp cells. The author also examined the effects of this material on cellular alkaline phosphatase activity as a potential indicator of dentinogenesis. For gene expression on MTA, reverse transcriptase polymerase chain reaction was performed using primer sets of glyceraldehyde-3-phosphate dehydrogenase, type I collagen, alkaline phosphatase(ALP), osteonectin, and dentin sialoprotein after 2 and 4 days. Cell viability assay showed that the proportion of MTA-treated pulp cells which had been exposed for 5 days to MTA was higher than that of the control cells. Among the genes investigated in this study, ALP and osteonectin(SPARC) were increased in MTA treated group than in control. These findings suggest that this dental pulp culture system may be useful in the future as a model for studying the mechanisms underlying dentin regeneration after the treatment with MTA. Exposure to MTA material would not induce cytotoxic response in the dental pulp cells. In addition, MTA could influence the behavior of human pulp cells by increasing the ALP activity and SPARC synthesis.

• Atmosphere
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• v.24 no.1
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• pp.123-130
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• 2014

The automated prediction system for seasonal tropical cyclone (TC) activity is established at the National Typhoon Center of the Korea Meteorological Administration (KMA) to provide effective operation and control of the system for user who lacks knowledge of the system. For automation of the system, two procedures which include subjective decisions by user are performed in advance, and their output data are provided as input data. To provide the capability to understand the operational processes for operational user, the input and output data are summarized with each process, and the directory structure is reconstructed following KMA's standard. We introduce a user interface using namelist input parameters to effectively control operational conditions which is fixed or should be manually set in the previous version of the prediction system. To operationally use early prediction which become available through the automation, its performances are evaluated according to initial condition dates. As a result, high correlations between the observed and predicted TC counts are kept for all track clusters even though advancing the initial condition date from May to January.

• Toxicological Research
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• v.21 no.4
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• pp.339-345
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• 2005

Aflatoxins are produced by Aspergillus flavus, parasiticus that grows in improperly stored cereals. Aflatoxin $B_1\;(AFB_1)$ is a potent hepatocarcinogen in a variety of experimental animals including human beings. In spite of a high attention to the hepatocarcinogenecity of aflatoxins, the relative toxicity of other types $(AFB_2,\;AFG_1\;and\;AFG_2)$ of the toxins is not fully clarified. Sprague-Dawley male rats were orally administered with $AFB_1,\;AFB_2,\;AFG_1\;and\;AFG_2$ at the dose of 250, 1250, and $2500\;{\mu}g/kg$ body weight. Animals were then killed at 12, 24 or 48 hrs following aflatoxin adminstration. Subsequently the relative weight of liver was measured and histopathological examination on the liver was performed. Level of 8-OxodG and expression of ras gene in the liver was determined. The relative liver weights at high doses of $AFB_1\;and\;AFG_1$ was significantly low. The treatment of $AFB_1$ at the high dose of $2500\;{\mu}g/kg$ showed vacuolar degeneration and centrilobular hepatic necrosis with inflammatory cells. The pathological changes by $AFB_2\;AFG_1,\;and\;AFG_2$ were not clearly found. The formation of 8-OxodG by $AFB_1$ increased in a dose-dependent manner up to 24 hrs after a single treatment of $AFB_1$ thereafter decreased to the level of the control. The treatments of $AFB_2\;AFG_1,\;and\;AFG_2$ showed an inconsistent pattern in the formation of 8-OxodG in the liver of rats with increasing time. The expression of ras oncogene in the liver by $AFB_1$ at the dose of $1250\;{\mu}g/kg$ was increased twice compared to the control. The treatments of $AFB_2\;AFG_1,\;and\;AFG_2$ at all doses decreased the expression of ras in the liver. These results in the present study indicate that $AFB_1$ among aflatoxins with low comparable levels is the most toxic as determined by early biomarkers such as 8-OxodG formation and ras expression. However, the levels of 8-OxodG and ras as biomarkers were not useful to predict the relative hepatocarcinogenicity of aflatoxins to $AFB_1$ in the present model. Further studies are required to look for other biomarkers to predict carcinogenic potency of aflatoxins.

• Journal of Environmental Health Sciences
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• v.38 no.6
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• pp.541-549
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• 2012

Objectives: This study was undertaken in order to evaluate a potential mechanism involved in gastro-intestinal problems observed in autistic subjects and uses an animal model of autism investigation. Methods: BTBR T+tf/J, a mouse strain with typical socio-behavioral characteristics of autistic subjects and FVB mice with highly social behaviors as the control strain were used. Both genders of mice aged three weeks and six months were used from four separate litters for each strain. Serum was prepared following cardiac puncture, and mesenteric lymph nodes were collected for in vitro stimulation and enumeration of major immune cell proportion. Results: The level of serum IgA was significantly enhanced in six-month-old BTBR mice compared with three-week-old BTBR, which was not observed with the FVB control mice. The serum IgE level was also higher among BTBR mice than among age-sex matched FVB mice, respectively. Considering the ratio of interleukin-4 vs interferon-gamma production from mesenteric lymph node T cells, skewedness toward type-2 reactivities was observed. In addition, the proportion of B cells in mesenteric lymph nodes was significantly higher in BTBR mice than in FVB mice. Conclusion: Upregulation of mucosal immunity related with enhanced type-2 immune reactivity observed in BTBR mice could be involved with the etiology of gastro-intestinal abnormalities in autism.

• Journal of Distribution Research
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• v.15 no.5
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• pp.37-60
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• 2010

Department Stores have been in place as typical large-scale retailer in Korean retail market. After Asian financial crisis in 1997, the market share of major three department stores has been increased and they have had a dominant position in relationship with vendors or manufacturers. Thus, they are able to control sales commission. Sales commission is defined as things that department stores which contribute to products sales instead of manufacturers take some portion of price as their revenue. In other words, vendors or manufacturers pay some amount of money from their sales by contracted ratio to department stores. The problem is that vendors or manufacturers think that sales commission is high. However, department stores have a different opinion that sales commission is not high because they generate new value from gathering customers and doing marketing activity on behalf of vendors or manufacturers. Because department stores have operated with business model of renting sales space to vendors or manufacturers instead of buying goods directly from them, this situation has been taken place. The revenue of department stores depend on sales commission. Thus, they want to get a dominant power to control sales commission in relationship with vendors or manufacturers. So, they have tried to increase their size and brand power. The considered policies related in sales commission of department stores are as following: preventing monopoly or oligopoly of department store, being strength of monitoring for department stores' unfair trade, strict enforcement of law for large-scale retailer's unfair trade, and inducing win-win strategy doing voluntarily by department stores.

• Archives of Pharmacal Research
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• v.25 no.5
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• pp.697-703
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• 2002

We investigated that the role of nitric oxide (NO) on ischemic rats in brain and heart. Ischemia was induced by both common carotid arteries (CCA) occlusion for 24h following reperfusion. Then tissue samples were removed and measured NOx. In brain, NOx was increased by about 40% vs. normal and it was significantly inhibited by aminoguanidine, selective iNOS inhibitor. This result showed that NOx concentration was increased by iNOS. We investigated the role of $Ca^{2+}$ during ischemia. Nimodipine, L-type calcium channel blocker, didn't inhibit the increases of NOx concentration during ischemia. It suggested that increased NOx was due to calcium-independent NOS. MK-801, which N-methyl-D-aspartate (NMDA) receptor antagonist, didn't significantly prevent the increases of NOx. In heart, ischemia caused NOx decrease and it is inconsistent with NOx increase in brain. Aminoguanidine and nimodipine didnt affect on NOx decrease. But MK-801 more lowered NOx concentration than those of ischemia control group. It seemed that $Ca^{2+}$ influx in heart partially occurred via NMDA receptor and inhibited by NMDA receptor antagonist. The mean arterial pressure (MAP) in ischemic rats after 24h of CCA occlusion was decreased when compared to normal value, whereas the heart rates (HR) was not different between two groups. Aminoguanidine or MK801 had no effect on MAP or HR, but nimodipine reduced MAP. There was no difference the effects of aminoguanidine, nimodipine, or MK-801, on MAP and HR between normal rats and ischemic rats. In summary, ischemic model caused an increase of NOx concentration, suggesting that this may be produced via iNOS, which is calcium independent in brain. However in heart, ischemia decreased NOx concentration and NMDA receptor was partially involved. The basal MAP was decreased in ischemic rats but HR was not different from normal control, suggesting that increased NOx in brain of ischemic rat may result in the hypotension.

• Journal of Periodontal and Implant Science
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• v.50 no.1
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• pp.14-27
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• 2020

Purpose: To overcome several drawbacks of chemically-crosslinked collagen membranes, modification processes such as ultraviolet (UV) crosslinking and the addition of biphasic calcium phosphate (BCP) to collagen membranes have been introduced. This study evaluated the efficacy and biocompatibility of BCP-supplemented UV-crosslinked collagen membrane for guided bone regeneration (GBR) in a rabbit calvarial model. Methods: Four circular bone defects (diameter, 8 mm) were created in the calvarium of 10 rabbits. Each defect was randomly allocated to one of the following groups: 1) the sham control group (spontaneous healing); 2) the M group (defect coverage with a BCP-supplemented UV-crosslinked collagen membrane and no graft material); 3) the BG (defects filled with BCP particles without membrane coverage); and 4) the BG+M group (defects filled with BCP particles and covered with a BCP-supplemented UV-crosslinked collagen membrane in a conventional GBR procedure). At 2 and 8 weeks, rabbits were sacrificed, and experimental defects were investigated histologically and by micro-computed tomography (micro-CT). Results: In both micro-CT and histometric analyses, the BG and BG+M groups at both 2 and 8 weeks showed significantly higher new bone formation than the control group. On micro-CT, the new bone volume of the BG+M group (48.39±5.47 ㎣) was larger than that of the BG group (38.71±2.24 ㎣, P=0.032) at 8 weeks. Histologically, greater new bone area was observed in the BG+M group than in the BG or M groups. BCP-supplemented UV-crosslinked collagen membrane did not cause an abnormal cellular reaction and was stable until 8 weeks. Conclusions: Enhanced new bone formation in GBR can be achieved by simultaneously using bone graft material and a BCP-supplemented UV-crosslinked collagen membrane, which showed high biocompatibility and resistance to degradation, making it a biocompatible alternative to chemically-crosslinked collagen membranes.

• The Korean Nurse
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• v.36 no.3
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• pp.49-69
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• 1997

The urgent needs to establish hospice care systems in Korea arise from the following reasons: 0) a drastic increase in chronically ill patients with the increase of aged population: (2) rapid changes in living environment from the traditional habitation (e. g., Many Koreans living in apartment complexes, which is the most popular form of modern residence in recent years, prefer to die in the hospital.): the overall increase in patients with advanced cancer: (4) recent trends in early discharge of terminally ill patients from the limited hospital facilities to accomodate other medical insurance beneficiaries; (5) easy acceptance of euthanasia owing to the recent social atmosphere that belittles the dignity of human life; (6) medical and nursing care of AIDS patient in terminal stage; (7) and the problem associated with inhumane medical care system, overtreatment, and groundless fears against narcotics. Terminally ill patients were used to be treated in the hospital in the past. In these days, however, they are forced to have home cares with little assistance from the qualified medical personnel because of insufficient hospital facilities, which are even short for the need of emergency patients and provide priority cares to medical insurance beneficiaries with other acute problems. And yet, neither are there any administrative organizations nor systematic medical studies that deal with the level of terminally ill patient's need, their family's problems and resources of hospice care systems in Korea. Thus, most patients are not able to get appropriate medical care at the terminal stage of their lives. The objective of this study is to make comprehensive database for various hospice care organization currently in operation, link them through medical information system, and develop an easily accessible hospice care model that meets the need of most Korean people. Our survey results may be summarized as follows: Nationally there are 40 organizations that provide partial or full hospice care. However, these organizations are not linked to any formal medical service network. Furthermore, the objective of hospice care, care principles, personnel with appropriate training, educational programs, standard for care, costs, consulting service to patients' family members, the extent of medical care from professional staff members, status of hospice facility, and management of those institutions are neither clearly defined nor organized compared to the international hospice care standards. The surveys on patients of terminal stage. grouped in hospice and non-hospice care patients. reveal what they want visiting nursing care to help their pain control. psychological. social and spiritual demands. While the more than 90% of hospice care patients want to reduce their pains. the non-hospice care patients. in addition to their desire for pain control. demanded more psychological. social and spiritual helps as well. The results of this research could be utilized to 0) define the standard of hospice care. (2) provide the guidance for hospice medical care costs. (3) establish the database of hospice care systems. (4) develop softwares. (5) build communication network through Medinet. and (6) provide an organized visiting home nursing care system. These information should be a valuable resource to many medical staffs who are involved in cancer therapy. nursing care. and social welfare programs.

• Nutrition Research and Practice
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• v.10 no.1
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• pp.11-18
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• 2016

BACKGROUND/OBJECTIVES: Type 2 diabetes (T2D) is more frequently diagnosed and is characterized by hyperglycemia and insulin resistance. $\small{D}$-xylose, a sucrase inhibitor, may be useful as a functional sugar complement to inhibit increases in blood glucose levels. The objective of this study was to investigate the anti-diabetic effects of $\small{D}$-xylose both in vitro and stretpozotocin (STZ)-nicotinamide (NA)-induced models in vivo. MATERIALS/METHODS: Wistar rats were divided into the following groups: (i) normal control; (ii) diabetic control; (iii) diabetic rats supplemented with a diet where 5% of the total sucrose content in the diet was replaced with $\small{D}$-xylose; and (iv) diabetic rats supplemented with a diet where 10% of the total sucrose content in the diet was replaced with $\small{D}$-xylose. These groups were maintained for two weeks. The effects of $\small{D}$-xylose on blood glucose levels were examined using oral glucose tolerance test, insulin secretion assays, histology of liver and pancreas tissues, and analysis of phosphoenolpyruvate carboxylase (PEPCK) expression in liver tissues of a STZ-NA-induced experimental rat model. Levels of glucose uptake and insulin secretion by differentiated C2C12 muscle cells and INS-1 pancreatic ${\beta}$-cells were analyzed. RESULTS: In vivo, $\small{D}$-xylose supplementation significantly reduced fasting serum glucose levels (P < 0.05), it slightly reduced the area under the glucose curve, and increased insulin levels compared to the diabetic controls. $\small{D}$-xylose supplementation enhanced the regeneration of pancreas tissue and improved the arrangement of hepatocytes compared to the diabetic controls. Lower levels of PEPCK were detected in the liver tissues of $\small{D}$-xylose-supplemented rats (P < 0.05). In vitro, both 2-NBDG uptake by C2C12 cells and insulin secretion by INS-1 cells were increased with $\small{D}$-xylose supplementation in a dose-dependent manner compared to treatment with glucose alone. CONCLUSIONS: In this study, $\small{D}$-xylose exerted anti-diabetic effects in vivo by regulating blood glucose levels via regeneration of damaged pancreas and liver tissues and regulation of PEPCK, a key rate-limiting enzyme in the process of gluconeogenesis. In vitro, $\small{D}$-xylose induced the uptake of glucose by muscle cells and the secretion of insulin cells by ${\beta}$-cells. These mechanistic insights will facilitate the development of highly effective strategy for T2D.