• Journal of Technologic Dentistry
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• v.31 no.2
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• pp.39-44
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• 2009

In the orthopedic field which firstly used zirconia as artificial joints, researchers had studied the reasons for collapsing zirconia used as restorative material by accumulated inner cracks in several years and they found out Low Temperature Degradation is one of the reasons. In the dentistry field, it has not been too long since they used zirconia as the cores of all-ceramic restoration; however, the study is needed as prophylactic measure against Low Temperature Degradation which can be caused by saliva wetting the mouth all the time and frictional forces such as bite pressure and masticatory pressure. Artificial aging by autoclaving is used because there are difficulties of testing in the patient's mouth. To study the changes in the material properties, the flexural strength of dental zirconia ceramic is measured before and after the test. The following are the result of the test. 1) The zirconia blocks in the autoclaves at $130^{\circ}C$ and $200^{\circ}C$ are phase-shifted tetragonal to monoclinic by Low Temperature Degradation. 2)The non-autoclaved specimens have the average fractural strength of 1346.4MPa, the specimens autoclaved at $130^{\circ}C$ have 1226.4Mpa and the specimens autoclaved at $200^{\circ}C$ have 1024.1MPa. The tests show that as the temperature increases, the flexural strength tend to decrease and the differences are noticeable(p<0.001). 3)Through the Duncan's post-hoc test, the differences in flexural strength of the 3 groups were listed in order of strength like normal temperature>at $130^{\circ}C$ autoclave low temperature degradation> at $200^{\circ}C$ autoclave low temperature degradation.

• Journal of Korean society of Dental Hygiene
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• v.20 no.1
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• pp.41-51
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• 2020

Objectives: The purpose of this study was to investigate the effects of oral health behaviors of patients with hypertension and diabetic patients on the number of remaining teeth in Korean adults over 45 years of age, furthermore, we also aimed to develop oral health care programs and health promotion for patients with hypertension and diabetes. Methods: Altogether, 1,526 subjects with hypertension and diabetes from the 6th Korean National Health and Nutrition Survey (2013-2015) were analyzed. Results: A multiple logistic regression analysis was performed to determine the effects of oral health behavior and periodontal disease on residual teeth in patients with hypertension and diabetes after adjusting for age. We found 1.53 times the risk of having less than 20 remaining teeth in the group of brushing more than 3 times a day (95% CI: 1.00,2.35, p<0.001), 2.27 times (95% CI: 1.23-4.17, p<0.05) in the group not using the dental floss group 0.05), compared to the group undergoing regular dental check-up (95% CI: 0.93-1.85, p>0.05), compared to the non-smoking group 0.77 times (95% CI: 0.51-1.14, p>0.05), 1.33 times (95% CI: 0.98-1.80, p>0.05) in the drinking group compared to the non-drinking group, in the periodontal disease group, the risk of having less than 20 remaining teeth was 2.19 times higher (95% CI: 1.48-3.24, p>0.001) than in the normal group. Conclusions: As a super-aging society, develops in Korea, the prevalence of hypertension and diabetes will increase gradually. Therefore, an oral health policy should be implemented at the national level for the prevention and treatment of periodontal disease as well as the management of oral health the elderly.

• Journal of Nutrition and Health
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• v.29 no.10
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• pp.1059-1071
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• 1996

This study was performed to investigate the effect of dietary protein level on renal senescence. Male rats of 337.8$\pm$5.7g body weight were underlateral nephrectomy or shamoperation. The rats were divided into high protein(40% casein), normal protein(15% casein) and low protein(8% casein)diets and fed experimental diets ad libitum for 24 weeks. The results are summarized as follows. There was a hypertophy of the remnant kidney of uninephrectomized rats of 40% or 15% protein group, coming up to the comparable weights of both kidneys of sham-operated rats. However, the hypertrophic effect was not seen in uninephrectomized rats of 8% protein group. Serum albumin was lower in uninephrectomized rats. With increasing dietary protein level blood urea nitrogen was increased, whereas, urinary urea nitrogen excretion was decreased. Urinary solute excretion was higher in uninephrectomized group than in sham-operated group. However, effect of dietary protein level on urinary solute excretion varied dpending on th solutes tested. GFR and urinary protein excretion, throughout experiment, increased with feeding period and with dietary protein level. Proteinuria was most severe in uninephrectomized rats fed 40% casein diet. Maximum urine concentration ability measured after dehydration was not different among the experimental groups. Light microscopic examination showed focal segmental glomerulosclerosis and mild increas of glomerular mesangial matrix in uninephrectomized rats fed 40% and 15% protein diet, however, which was not observed in uninephrectomized rats fed 8% protein diet and in sham-operated rats fed 40% diet. Immunofluorescence studies revealed segmental deposits of albumin in the mesangium and capillary loops in high protein and uninephrectomized groups. Minimal granular deposition of IgG was noted in the mesangium of all experimental groups. In conclusion, high protein intake accelerated deterioration of renal function and it was correlated with morphological change. Low protein intake was effective in preventing these changes.

• Journal of Korean Neurosurgical Society
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• v.29 no.11
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• pp.1505-1513
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• 2000

Objectives : Many surgical procedures have been introduced to a symptomatic lumbar stenosis. Most of these procedures still have been regarded as an extensive surgical intervention with respect to normal aging process of the lumbar spine. We adopted a microsurgical decompression procedure via unilateral exposure as a minimally invasive intervention for symptomatic lumbar stenosis without instability. Materials and Methods : Fifty-seven patients with symptomatic lumbar stenosis underwent microsurgical decompression via unilateral laminotomy between March 1998 and December 1999. The conceptual modification and technical refinements were added to the previously reported microsurgical decompression procedure. Bilateral decompression through a unilateral laminotomy hole was performed in 11 patients. These patients profile also included 9 cases of degenerative spondylolisthesis(Grade I) without instability. Results : Preoperative neurogenic intermittent claudication(NIC) was more notably improved than low back pain, 60% to 82% during the follow-up period. Overall clinical results were excellent in 20(35%), good in 29(51%), fair in 6(11%) and poor in 2(3%). Conclusions : Microsurgical decompression for lumbar stenosis with stable spine provided a satisfactory symptomatic improvement without extensive destruction of the weight-bearing structures and functional mobile segments, even bilateral symptoms existed.

• The Journal of Korean Medicine
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• v.29 no.1
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• pp.106-116
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• 2008

Objectives : Peroxynitrite $(ONOO^-)$, superoxide anion radical $({\cdot}O_2^-)$ and nitric oxide (NO) are cytotoxic because they can oxidize several cellular components such as proteins, lipids and DNA. They have been implicated in the aging processes, and age-related diseases such as Alzheimer's disease, rheumatoid arthritis, cancer and atherosclerosis. The aim of this study was to investigate the $ONOO^-$, NO, and $({\cdot}O_2^-)$ scavenging and anti-inflammatory activities of Mori Fructus in ob/ob mice. Methods : Mice were grouped and treated for 5 weeks as follows. Both the normal lean (C57/BL6J black mice) and control obese (ob/ob mice) groups received the standard chow. The experimental groups were fed a diet of chow supplemented with 7.5, 15 and 30 mg Mori Fructus per 1 kg of body weight for 14 days. For this study, the fluorescent probes, namely 2',7'-dichlorodihydrofluorescein diacetate (DCFDA), 4,5-diaminofluorescein (DAF-2) and dihydrorhodamine 123 (DHR 123) were used. Western blotting was performed using anti-phospho $I{\kappa}B-\alpha$, anti-IKK-$\alpha$, anti-NF-${\kappa}B$ (p50, p65), anti-COX-2 and anti-iNOS respectively. Results : Mori Fructus inhibited the generation of $ONOO^-$, NO and $({\cdot}O_2^-)$ in the lipopolysaccharide (LPS)-treated mouse kidney postmitochondria in vitro. The generation of $ONOO^-$, NO and $({\cdot}O2^-)$ were inhibited in the Mori Fructus-administered ob/ob mice groups. The GSH/GSSG ratio decreased in the ob/ob mice, whereas they improved in the Mori Fructus-administered groups. Mori Fructus inhibited the expression of phospho $I{\kappa}B-\alpha$, IKK-$\alpha$, COX-2, iNOS genes, and thereby the activation of NF-$I{\kappa}B$. Conclusions : These results suggest that Mori Fructus is an effective $ONOO^-$, $({\cdot}O_2^-)$ and NO scavenger, and therefore it might be a potential therapeutic drug against the inflammation process and inflammation-related diseases.

• Korean Journal of Pharmacognosy
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• v.40 no.4
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• pp.382-387
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• 2009

Enhanced formation and accumulation of advanced glycation end products (AGEs) have been implicated as a major pathogenesis process leading to diabetic complications, normal aging, atherosclerosis and Alzheimer's disease. In our ongoing project to discover novel treatments for diabetic complications from natural sources, we have investigated on the inhibitory activity of 67 ethanol extracts from 57 Korean herbal medicines against the formation of AGEs in vitro. Of these, 22 extracts were found to have a significant AGEs inhibitory activity ($IC_{50}$<50 ${\mu}g$/ml) compared with aminoguanidine ($IC_{50}$=75.98 ${\mu}g$/ml). Particularly, 6 extracts from 3 herbal medicines, Castanea crenata (flower, leaf, bark-twig), Acer tatarium subsp. ginnala (fruit) and Sapium japonicum (leaf, twig) showed (approximately 8-17 fold) stronger inhibitory activity than that of aminoguanidine.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.9 no.1
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• pp.15-19
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• 2013

The auxiliary feedwater is an important to remove the heat from the reactor core when the main feedwater system is unavailable. In most initiating events in Probabilistic Safety Assessment(PSA), the operaton of this system is required to mitigate the accidents. For one of domestic nuclear power plants, a design change of a turbine-driven auxiliary feedwater pump(TD-AFWP), pipe, and valves in the auxiliary system is implemented due to the aging related deterioration by long time operation. This change includes the replacement of the TD-AFWP, the relocation of some valves for improving the system availability, a new cross-tie line, and the installation of manual valves for maintenance. The design modification affects the PSA because the system is critical to mitigate the accidents. In this paper, the safety effect of the change of the auxiliary feedwater system is assessed with regard to the PSA view point. The results demonstrate that this change can supply the auxiliary feedwater from the TD-AFWP in the accident with the motor-driven auxiliary feedwater pump(MD-AFWP) unavailable due to test or maintenance. In addition, the change of MOV's normal position from "close" to "open" can deliver the water to steam generator in the loss of offsite power(LOOP) event. Therefore, it is confirmed that the design change of the auxiliary feedwater system reduces the total core damage frequency(CDF).

• Journal of Nutrition and Health
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• v.35 no.9
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• pp.962-969
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• 2002

This study examined the effect of calcium supplementation and exercise on bone mineral density (BMD) and general characteristics, dietary intake and biochemical measurements for 45 healthy middle-aged women (40-57 years). Subjects were divided in to 4 groups; control group (G1), exercise group (G2), calcium supplementation group (G3), and calcium supplementation with exercise group (G4). The subjects were 45.8$\pm$ 0.66 years old. BMI(kg/$m^2$) was 23.31 $\pm$ 0.63 in Gl group, 22.92 $\pm$ 0.51 in G2 group, 23.64 $\pm$ 0.61 in G3 group, 23.40 $\pm$ 0.37 in G4 group, and BMI of all groups were in normal value. Energy intake was 1332.28㎉/day, 60% of RDA, so that may be unbalance of micronutrients. Especially, calcium intake was 62.8% of RDA that was very low level. Osteocalcine was not statistically significant but calcium supplementation group (G3) be showed increase. BMD was usually decreased by Aging, but in this study was increased in the all group, except control group. It showed increase of BMD for calcium supplementation and/or exercise. Overall results indicate that calcium supplementation and/or exercise increased BMD of middle-aged women, but long-term calcium supplementation and exercise will be able to more effect.(Korean J Nutrition 35(9) : 962~969, 2002)

• Women's Health Nursing
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• v.3 no.1
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• pp.82-92
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• 1997

The purpose of this study was attempted to understand the substance and meaning of menopause experienced by women through informal interviews with oral consent. The informants were 6 perimenopausal women of 50-55 years old who are executing menopause. Colaizz's analytical method, a type of phenomenological analysis, was used to analyze data recorded by audiotape. One professor and a master's degree student who understand phenomenology, and the one who has a master of arts examined the validity between the meanings composed of the clusters of themes. Findings were turned out to be valid through validation process as the last step. The meaning of menopause implied both 'concept about menopause' and 'menopause as a time of change'. Menopause was mostly considered as cessation of menstruation as a physiological, natural, and normal process by aging. However, some people regarded menopause as a loss of youth and womanhood and lessening of every function of the body. Menopause as the time of changes means 'the period of' 'hormonal changes' such as change of menstruation, hot flushes, perspiration, and palpitation ; 'body function changes' of visual acuity, physical strength, sleeping, digestion, thoughts, bone and joints, skin sensibility, sexual pattern and intelligence ; 'emotional changes' such as anxiety, loneliness, gloominess, and nervousness. Menopause is a turning point on the women's life cycle accompanying various kind of changes and health problems. Therefore it is inevitable to develop strategy helping menopausal women pass through the critical successfully by adapting and coping with their critical period toward the healthy and better quality of life individually rather than putting them all into the standardized hormonal replacement protocol.

• Nutrition Research and Practice
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• v.12 no.5
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• pp.415-425
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• 2018

BACKGROUND/OBJECTIVE: As aging progresses, the number of patients with cognitive impairment also increases. Cognitive function is not generally correlated with diet, and there is debate over that association. Thus, the present study aimed to investigate the association between dietary intake and cognitive function among adults aged 50 years or older. SUBJECTS/METHODS: Between July 2017 and March 2018, 324 adults aged over 50 years from Gwangju Sun-Han hospital participated in a dietary survey. The frequency of food intake and related information were collected using a semi-quantitative food frequency questionnaire (SQ-FFQ) and determining the mini-mental state examination (MMSE) level for 276 participants. The association between dietary intake and cognitive function was assessed by performing logistic regression analysis. RESULTS: Depending on the MMSE score, the participants' age, education level, inhabitation status, medications, alcohol consumption, sleep duration, physical activity, and short geriatric depression scale score were significantly different (P < 0.05). Moreover, those participant characteristics were associated with either decreased or increased odds ratios (OR) for the risk of mild cognitive impairment (MCI). Based on analysis of the participants' intake of 112 detailed food items, which were categorized into 20 food types, intakes of cooked white rice (< 2 times/day compared with ${\geq}3$ times/day) (P < 0.05), properly cooked rice with other grains and legumes (P < 0.001), fruits (P < 0.05), milk (low fat and normal) (P = 0.044), liquid-type yogurt (P = 0.019), and curd-type yogurt (P = 0.015) were found to significantly decrease the OR for the risk of MCI. CONCLUSIONS: Associations were significant between the risk of MCI and the intake of certain food types. Specifically, a moderate intake of cooked white rice and an adequate intake of whole grains, fruits, milk, and dairy products were associated with reduced risks of MCI among adults aged over 50 years.