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Life-time Prediction of a FKM O-ring using Intermittent Compression Stress Relaxation (CSR) and Time-temperature Superposition (TTS) Principle (간헐 압축응력 완화와 시간-온도 중첩 원리를 이용한 FKM 오링의 수명 예측 연구)

  • Lee, Jin-Hyok;Bae, Jong-Woo;Kim, Jung-Su;Hwang, Tae-Jun;Park, Sung-Doo;Park, Sung-Han;Min, Yeo-Tae;Kim, Won-Ho;Jo, Nam-Ju
    • Elastomers and Composites
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    • v.45 no.4
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    • pp.263-271
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    • 2010
  • Intermittent CSR testing was used to investigate the degradation of an FKM O-ring, also the prediction of its life-time. An intermittent CSR jig was designed taking into consideration the O-ring's environment under use. The testing allowed observation of the effects of friction, heat loss, and stress relaxation by the Mullins effect. Degradation of O-rings by thermal aging was observed between 60 and $160^{\circ}C$. In the high temperature of range ($100-160^{\circ}C$) O-rings showed linear degradation behavior and satisfied the Arrhenius relationship. The activation energy was about 60.2 kJ/mol. From Arrhenius plots, predicted life-times were 43.3 years and 69.9 years for 50% and 40% failure conditions, respectively. Based on TTS (time-temperature superposition) principle, degradation was observed at $60^{\circ}C$, and could save testing time. Between 60 and $100^{\circ}C$ the activation energy decreased to 48.3 kJ/mol. WLF(William-Landel-Ferry) plot confirmed that O-rings show non-linear degradation behavior under $80^{\circ}C$. The life-time of O-rings predicted by TTS principle was 19.1 years and 25.2 years for each failure condition. The life-time predicted by TTS principle is more conservative than that from the Arrhenius relationship.

A Literature Study of the Teeth (치(齒)에 대(對)한 문헌적(文獻的) 고찰(考察))

  • Gwak, Ik-Hun;Yun, Cheol-Ho;Jeong, Ji-Cheon
    • The Journal of Internal Korean Medicine
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    • v.16 no.2
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    • pp.146-177
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    • 1995
  • The purpose of this study was to investigate the relationship between the teeth and Zhang-Fu(臟腑), dental diseases, and the hygiene of the mouth through the literature of oriental medicine. First, the relatonship between the teeth and Zhang-Fu is reviewed as follows: The teeth are influenced by Shen(腎) because they are the end of bone and Biao(標) of Shen. Gingiva is related to Wei(胃) and Da-Chang(大腸) because it is passed by Yangming-Channel(陽明經). The growth and nutrition of teeth depends on Shen. The pathological condition of Shen causes the gingival atrophy, the loose of teeth, dedentition due to aging, withering of teeth, and tartar: whereas the pathological condition of Wei and Da-Chang causes toothache, gingivitis, inflamed gums, bad breath, and gingival hemorrhage. Second, the causes and therapies of dental diseases through the literature can be summarized as follows: The major causes of toothache are the pathogenic condition of wind-heat and wind-cold, the heat syndrome of Wei, the damp-heat of intestine, flaring-up of fire of deficiency type, rotten tooth, etc... The principal causes of dedentition and the shaking and loose of teeth are the deficiency of Shen, and the rest of causes are the damp-heat of Yangming. Gingival atrophy is caused by the deficiency of Shen, whereas the gingival hemorrhage comes from the factors in the pathogenic factor of wind-heat of Yangming-Channel, the heat syndrome of stomach, and the deficiency of Shen. The causes of grinding of teeth during sleeping are stomach-heat, and the delayed dentition and the withering result from the deficiency of Shen-Jing.(腎精) The principal therapies of toothache are removing wind and heat, clearing away heat and prompting diuresis, clearing away the stomach-heat, replenishing vital essence to tonify the Shen, relieving superficial syndrome by wind-cold, and alleviating pain by destroying parasites. For the prescription of the principal therapies, there are Xijio Dihuang Tang, Jiajian Ganlu Yin, Qufeng Wan, Qingwei San, Tiaowei Chenggi Tang Shengong Wan, Liangge San Qingwei Tang Yunu Jian, Liuwei Dihuang Wan Zuogui Yin Bawei Wan Wanshao Dan, Xixin San Badou Wan Gianghuo Fuzi Tang, Jiuzi Tang Badou Wan, etc... The therapies of dedentition and the shaking and loose of teeth are replenishing vital essence to tonify the Shen, and warming and recuperating the Shen-Yang: as the prescription, there are Liuwei Dihuang Wana Zuogui Yin, and Bawei Wan Anshen Wan Wanshao Dan Yougui Wan etc... The therapies of gingival hemorrhage are clearing away the stomach-heat, replenishing vital essence to tonify the Shen, warming and recuperating the Shen-Yang(腎陽), and moisturing and purging intence heat with the prescription of Tiaowei Chenggi Tang Xijiao Dihuang Tang, Liuwei Dihuang Wan Zuogui Yin, Bawei Wan Anshen Wan, and Yunu Jian. The therapy of gingival atrophy is replenishing vital essence to tonify the Shen in the prescription of Liuwei Wan Bawei Wan Ziyin Dabu Wan. The therapies of grinding of teeth during sleeping are clearing away the stomach-heat and purging intense heat, and invigorating the spleen through eliminating dampness in the prescription of Qingwei San, Wumei Wan, etc... The therapy of delaed dentition is replenishing vital essence to tonify the Shen with the prescription of Liuwei Wan Buyin Jian, etc... Third, clinical treatment reports of dental diseases are reviewed as follows: The toothache due to stomach-heat was treated by medical herbs like Gypsum, Natrir Sulfas, Rehmanniae, Schizonepetal Herba, Menthae Folium, Cimicifugae Rhizoma, and Scrophulariae Radix. The therapies of toothache due to flaring-up of fire in deficiency type from deficiency of Shen provided with replenishment of vital essence to tonify the Shen and clean ministerial fire, and the prescription was the kind of Liuwei Wan, which worked very well. The therapy of dedentition and loose of teeth due to deficiency of Shen was done to stablize the teeth as tonifing the Shen with the prescription of Guchi Wan. The rate of imrovement was over 90%. The destruction of periodontal tissue due to periodonititis was cured of dispelling wind, reducing heat, and alleviating pain, It was improved by taking Zizhi Xingiong Tang, Guchi Xiaotong San, Yunii Jian, and Qingwei San about 3-7 days, and the rate of improvement was over 80%. Fourth, the prevention and regimens are reviewed as follows: As a physical and breathing exercise of the teeth, tapping teeth which stimulates the circulation of Qi(氣) and Xue(血) had been used. The tapping time of 14, 17, 36, etc... has been reported, and it should be applied based on the body condition. The medical herbs for gargling and brushing teeth have been used. Specifically, Cimicifugae Rhizoma, Gypsum, Gypsum Fibrosum, and Indigo pulrelrata Lereis have been used to reduce heat, Coptidis Rhizama and Yang Jinggu to eliminate damp-heat, Amomi Semen, Cyperi Rhizoma, Flos Caryophylli, Asari Radix, Piperis Longi Fructus, Santali Albae Lignum, Meliae Fructus, Moschus, Aquillaiae Lignum, and Borneol to promote the circulation of Qi and to relieve pain, Ligustici Radix, Angelice Radix, Rhizoma Nardostachydis, Tribuli Semen to relieve superficial syndrome by means of diaphiresis, and Cnidii Rhizoma, Angelicae sinensis Radix, and Olibanum to promote blood circulation to stop pain.

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A Study of Improvement Plans for Urban Parks through the Application of Barrier-free Living Environment Certification Standards - A Focus on Boramae Park- (장애물 없는 생활환경 인증기준을 적용한 도시공원 개선계획 - 보라매공원을 대상으로 -)

  • Seo, Eun-Sil;Koo, Bon-Hak
    • Journal of the Korean Institute of Landscape Architecture
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    • v.43 no.5
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    • pp.100-110
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    • 2015
  • With the trend for the construction of barrier-free living environments in accordance with the ever-increasing external activity of the aging population, multi-culture families and socially disadvantaged, there is also a demand for the facilities improvement at parks for their convenience of use. This study analyzed the possibility of Barrier-Free Certification of an existing open space and defined its prototype renovation plan. This study is intended to help develop Borame Park into a barrier-free park by securing a barrier-free line of movement linking the major facilities sites within the park, improving park facilities lest there should be inconvenience in the use of the major facilities, and a guidance system convenient for use by physically and mentally impaired people. The significance of this study lies in the fact that it diagnosed the possibility of the BF Certification of existing urban parks and established a barrier-free park, which is easy for anyone to use. In the course of doing research on this, this study was able to discover the limitations of the BF Certification system, and its related tasks to be solved in the future as follows: The first thing this study shows is that there is a lack of understanding and awareness of the BF Certification system. Basically, there is a need for giving consideration to the development of a barrier-free living environment from the planning and design phase of a park, but in actuality, an examination of the certification is undertaken at the time of the completion of design and construction, which causes a large loss both time-wise and economically. Second, as evaluative items for the BF Certification of a park, applied are detailed evaluation items that fail to reflect the characteristics of an outdoor space whose natural constraints are large, such as geographical highs and lows and existing trees, plants, etc. Third, guidelines for establishment of a barrier-free park must be created in the light of the locational conditions of the park, followed by improvements of its BF Certification evaluation items.

Reduction of Mitochondrial Electron Transferase in Rat Bile duct Fibroblast by Clonorchis sinensis Infection (간흡충(Clonorchis sinensis)감염에 의한 흰쥐 담관 섬유모세포 미토콘드리아 전자전달효소의 감소)

  • Min, Byoung-Hoon;Hong, Soon-Hak;Lee, Haeng-Sook;Kim, Soo-Jin;Joo, Kyoung-Hwan
    • Applied Microscopy
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    • v.40 no.2
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    • pp.89-99
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    • 2010
  • Fibroblasts are the most common cells in connective tissue and are responsible for the synthesis of extracellular matrix components. The fibrosis associated with chronic inflammation and injury may contribute to cholangiocarcinoma pathogenesis, particularly through an increase in extracellular matrix components, which participate in the regulation of bile duct differentiation during development. Mitochondria produce ATP through oxidative metabolism to provide energy to the cell under physiological conditions. Also, mitochondrial dysfunction and oxidative stress have been implicated in cellular senescence and aging. Alternations in mitochondrial structure and function are early events of programmed cell death or apoptosis and mitochondria appear to be a central regulator of apoptosis in most somatic cell. Clonorchis sinensis, one of the most important parasite of the human bile duct in East Asia, arouses epithelial hyperplasia and ductal fibrosis. Isolated fibroblast from the bile ducts of rats infected by C. sinensis showed increase of cytoplasmic process. In addition, decrease of cellular proliferation was observed in fibroblasts which was isolated from normal rat bile duct and then cultured in media containing C. sinensis excretory-secretory product. However, the effects of C. sinensis infection on the mitochondrial enzyme distribution is not clearly reported yet. Therefore, we investigated the structural change of C. sinensis infected bile duct and mitochondrial enzyme distribution of the cultured fibroblast isolated from the C. sinensis infected rat bile duct. As a result, C. sinensis infected SD rat bile ducts showed the features of chronic clonorchiasis, such as ductal connective and epithelial tissue dilatation, or ductal fibrosis. In addition, fibroblast in ductal connective tissue was damaged by physical effect of fibrotic tissue and chemical stimulation. Immunohistochemically detected mitochondrial electron transferase (ATPase, COXII, Porin) was decreased in C. sinensis infected rat bile duct and cultured fibroblast from infected rat bile duct. It can be hypothesized that the reason why number of electron transferase decrease in fibroblast isolated from the rat bile duct infected with C. sinensis is because dysfunction of electron transport system is occurred mitochondrial dysfunction, increase of ROS (reactive oxygen species) and apoptosis after chemical damage on the cell caused by C. sinensis infection. Overall, C. sinensis infection induces fibrotic change of ductal connective tissue, mutation of cellular metabolism in fibroblast and mitochondrial dysfunction. Consequently, ductal fibrosis inhibits fibroblast proliferation and decreases mitochondrial electron transferase on fibroblast cytoplasm. It was assumed that the structure of bile duct could not normalized and ductal fibrosis was maintained for a long period of time according to fibroblast metamorphosis and death induced by mitochondrial dysfunction.

Correlation Between Vertebral Marrow Fat Fraction Measured Using Dixon Quantitative Chemical Shift MRI and BMD Value on Dual-energy X-ray Absorptiometry (Dixon 정량 화학적 변위 자기공명영상을 이용한 척추 골수 지방함량과 이중에너지 방사선 흡수법의 BMD 값의 비교)

  • Youn, In-Young;Lee, Hwa-Yeon;Kim, Jae-Kyun
    • Investigative Magnetic Resonance Imaging
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    • v.16 no.1
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    • pp.16-24
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    • 2012
  • Purpose : The purpose of this study was to determine whether there is a significant correlation between vertebral marrow fat fraction measured using Dixon quantitative chemical shift MRI (QCSI) and BMD on dual-energy X-ray absorptiometry (DXA). Materials and Methods: This retrospective study included 68 healthy individuals [mean age, 50.7 years; range, 25-76; male/female (M/F) = 36/32] who underwent DXA of the L-spine and whole body MRI including QCSI of the L-spine and chemical shift MRI of the liver. The enrolled individuals were divided into subgroups according to sex and T-score [i.e., normal bone density (M/F=27/23) and osteopenia (M/F=9/9)]. Vertebral marrow (Dixon QCSI, TR/TE 10.2/4.8 ms) and hepatic fat fractions (chemical shift technique, TR/TE 110/4.9 and 2.2 ms) were calculated on MRI. We evaluated whether there were significant differences in age, body mass index (BMI), vertebral marrow fat fraction, or hepatic fat fraction among the subgroups. Whether or not the participant had reached menopause was also evaluated in females. The correlations among variables (i.e., age, BMI, vertebral marrow and hepatic fat fractions, BMD) were evaluated using Spearman's correlation method. Results: There were no significant differences in age, BMI, or vertebral marrow and hepatic fat fractions between the two male subgroups (normal bone density vs. osteopenia). In female subjects, mean age in the osteopenic subgroup was greater than that in the normal subgroup (p=0.01). Presence of menopause was more common in the osteopenic subgroup [77.8% (7/9)] than the normal subgroup [26.1% (6/23), p<0.05]. The other variables showed no significant difference between female subgroups. The only significant correlation with marrow fat fraction after partial correlation analysis was that with age in the female subjects (r=0.43, p<0.05). Conclusion: The vertebral marrow fat fraction calculated using the Dixon QCSI does not precisely reflect the mild decrease in BMD for either sex.

The Effect of Green Coffee Bean Extract Supplementation on Body Fat Reduction in Overweight/Obese Women (과체중 여성에서 생커피두 엑기스의 섭취가 체지방 개선에 미치는 영향)

  • Park, Ju-Yeon;Kim, Ji-Young;Lee, Sung-Pyo;Lee, Jong-Ho
    • Journal of Nutrition and Health
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    • v.43 no.4
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    • pp.374-381
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    • 2010
  • This study was performed to examine the diet effect of green coffee bean extract on body fat reduction. Overweight/obese women (body mass index > $23\;kg/m^2$ or body fat > 27%) who were not diagnosed any type of disease were included in this study and subjects were randomly assigned to green coffee bean extract group (n = 23) or placebo group (n = 20). We measured anthropometric parameters, abdominal fat distribution by computed tomography and blood components before and after the 8-weeks intervention period. After supplementation, green coffee bean extract group showed a significant reduction of body weight (p < 0.01), body fat percent (p < 0.01), total fat area at L1 vertebra (-4.8%, p < 0.05) and visceral fat area at L4 vertebra was(-4.7%, p < 0.05). In addition, total fat area and visceral fat area at L1 vertebra decreased significantly in green coffee bean extract group compared with placebo group (p < 0.05, p < 0.05 respectively). The result of present study demonstrated that the supplementation of green coffee bean extract for 8 weeks can give beneficial effects on body fat reduction and visceral fat accumulation.

Prevalence of anatomical alar band (콧방울띠의 유병율)

  • Kim, Jung Suk;Kim, Cheol Soon;Cha, Jung Yul;Kim, Hee Jin;Hwang, Chung Ju
    • Journal of the Korean Academy of Esthetic Dentistry
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    • v.24 no.1
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    • pp.4-12
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    • 2015
  • Purpose: Due to the presence of various muscles around lips, variety of facial expression can be made and changes from aging process such as wrinkles can develop on the facial skin by the action of multiple muscles. In animals, skin and muscles are developed in the entire body. On contrast, they are well developed only in the face and just one is present in the neck and the palm. Alar band was defined as outer wrinkle formed by zygomaticus minor muscle, which is common in Koreans. This study aimed to investigate clinical prevalence of alar band. Materials & Methods: Subjects were chosen from 780 new patients who visited private clinic in Gyeonggi province for orthodontic treatment. Presence of alar band was examined from the smile extraoral photos. Correlation among skeletal form, lip protrusion, gender, and age were evaluated. Results: Prevalence of alar band was higher in women (27.9%) than in men (18.5%) with statistical significance (p<0.05). With respect to age, prevalence of alar band was 19.4% in age 0-9 y, 16.9% in age 10-19 y, 31.2% in age 20-29 y, 39.5% in age 30-39, 56.5% in age 40-49. Prevalence was gradually increased from patients in their 20s to patients in their 40s and statistical significance was found (p<0.001). Concerning SN_NP, prevalence was 26.2% in normodivergent facial type, 22.0% in hyperdivergent facial type, and 32.2% in hypodivergent facial type. Hypodivergent facial group had higher prevalence but statistical significance was not observed. Statistically significant difference was not found regarding upper lip. However, prevalence of the alar band was 26% in patients with normal lower lip, 14.7% in patients with pretruded lower lip, and 33.3% in retruded lower lip. The prevalence was higher in patients with retruded lower lip with statistical significance (p<0.05). Conclusions: 27.8% on previous anatomical study and this study showed 27.8% prevalence of alar band in clinical smile photographs. Clinical photograph study showed that alar band was more prominent in women, older people, and people with retruded lips with statistical significance. This will provide valuable diagnostic information for esthetic consideration.

Variation of Growth Characteristics and Quality Related Components in Korean Indigenous Tea (Camellia sinensis) Germplasms (한국 재래종 차나무(Camellia sinensis)의 작물학적 특성 및 품질관련 성분 변이)

  • Lee, Min-Seuk;Lee, Jin-Ho;Lee, Jeong-Dae;Hyun, Jin-Wuk;Kim, Young-Gul;Hwang, Young-Sun;Lee, Hyeon-Jin;Choi, Su-San-Na;Lee, Su-Jin;Choung, Myoung-Gun
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.53 no.3
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    • pp.333-338
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    • 2008
  • The tea has traditionally been used as a foodstuff by unique flavor, however recently not only the diversity of consumer demands but also the public interest in unique favorite and functional aspects have increased. It has been also reported that the main components contained in the leaves of tea (Camellia sinensis) include total nitrogen, free amino acids, polyphenols, and fiber, of which catechin has powerful bioactive effect such as anti-cancer, anti-aging, and anti-diabetic. (-)-Epigallocatechin gallate (EGCG) which is a major phenolic constituent of green tea extract has received considerable attention for a variety of important bioactivities. This study was carried out to obtain useful information for tea breeding programs, and to investigate the concentration of quality and functional related components in Korean indigenous tea germplasms. Korean indigenous tea lines were classified into three groups of sprout time, i.e, early, medium and late sprout time, and the ratio were 20%, 43% and 37%, respectively. There was a difference in characteristics among these Korean indigenous tea lines, leaf width of those ranged from 19.8 to 75 mm, leaf length was 35.5-160.0 mm, and leaf area was $660-8,400\;mm^2$. Experimental data on chlorophyll content (SPAD value) of Korean indigenous tea genetic resources ranged from 51.3 to 82.3. The concentrations of the total nitrogen, total free amino acids, and theanine were ranged 4.18-6.07%, 2.87-4.58%, and 1.64-2.66%, respectively. Also, catechin concentration showed from 11.54 to 15.07%, and concentration of caffeine was 2.82-4.23%. These results indicated indicated that it is possible to select elite lines with high concentration of quality related components and low concentration of caffeine from Korean domestic tea germplasms.

Reaction of Near-Isogenic Lines with Resistance to Bacterial Blight to Korean and Japanese isolates of Xanthomonas oryzae pv. oryzae (한국 및 일본 균주에 대한 벼흰잎마름병 저항성 근동질 유전자 계통의 반응)

  • Kim, Bo-Ra;Yang, Cheol-Woo;Jin, Xuan-Ji;Han, Jin-Soo;Lee, Eun-Jeong;Choi, Jae-Eul
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.52 no.1
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    • pp.89-99
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    • 2007
  • To develop durable and stable breeding strategies far the control of rice bacterial blight (BB) disease, the near-isogenic lines (NILs) with diverse resistance genes to BB isolates were evaluated in plant at three different growth stages using four Korean ($K_1,\;K_2,\;K_3,\;K_{3a}$) and three Japanese isolates (I, II, III). The resistance of the NILs to seven BB isolates tended to increase with plant aging. At the seedling stage, the NILs with single resistance genes were mostly resistant to $K_1$ race but they showed partial or no resistance to other isolates. A NILs (IRBB5) possessing xa5 had full resistance to the four Korean isolates, illustrating that it is a useful source to give enhancement to Korean breeding program. At the maximum tillering stage, resistance of NILs to $K_2,\;K_3$, I and II isolates considerably increased while resistance to $K_1,\;K_{3a}$ and III were similar to those of seedling stage. NILs with resistance gene of Xa4, xa5 and Xa7 proved to be the most stable to BB isolates at the maximum tillering stage. At the heading stage, most resistance genes of NILs were effective against BB isolates, and xa5 showed the consistent resistance to all the BB isolates including $K_{3a}$ and III isolates, demonstrating that resistance genes of Xa4, xa5 and Xa7 can be used either alone or combined to enhance resistance to BB disease in Korea.

Synthesis and Characterization of Layered Copper Hydroxides in Highly Concentrated Solution (고농도 용액에서 Layered Copper Hydroxides의 합성 및 특성)

  • Nam, Dae-Hyean;Choi, Choong-Lyeal;Kim, Kwang-Seop;Seo, Young-Jin;Park, Man
    • Korean Journal of Soil Science and Fertilizer
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    • v.43 no.6
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    • pp.872-879
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    • 2010
  • Layered copper hydroxides [LCHs, $Cu_2(OH)_3{\cdot}NO_3$] has the agricultural potentials as a fungicide because of its high crystallinity, excellent anion exchange capacity, and its regular layered particle size. The study, for the first time, has synthesized LCHs in highly concentrated solution and evaluated its physicochemical properties including the crystallinity and suspension stability. Optimal synthetic condition of LCHs was determined by crystallinity and stability of suspension as follow; 1) concentrations of $Cu(NO_3)_2$ and NaOH solutions were 3.0 M respectively, 2) reaction temperature and solution pH were $25^{\circ}C$ and 6.0, respectively, and 3) aging time after reaction was 2hr. Crystallinity of LCHs enhanced with increase in pH up to 9.0. Whereas, stability of suspension was decrease by increase in crystal size. Especially, increase in reaction temperature decreased stability of suspension. XRD patterns and SEM images exhibited that LCHs had regular layered particle size with 0.2~0.8 ${\mu}m$ and high crystallinity in optimal synthetic condition. The particle size was increased with increase in reaction temperature and pH. These results showed that LCHs synthesized in highly concentrated solution exhibited high stability of suspension as well as high crystallinity suitable to their potential as a fungicide.