• 한국지하수토양환경학회지:지하수토양환경
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• 제13권5호
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• pp.47-56
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• 2008

금속이 염 용액 형태로 토양에 유입될 때, 그 금속의 용해도는 시간이 지남에 따라 감소하는 경향(aging)을 보이는데, 이러한 시간 의존성 외에 토양 내 금속 용해도의 변화에 영향을 미치는 또 다른 요인들에 대한 고찰은 아직 미비한 상태이다. 본 연구에서는 물리화학적 성질이 다른 5 종류의 토양 (히스토졸, 앤디졸, 옥시졸, 미세입자 알피졸, 조대입자 알피졸)에 여러 비율의 카드뮴(2.5-20 mg ${kg}^{-1}$)/ 구리(50-400 mg${kg}^{-1}$)/ 아연(50-400 mg ${kg}^{-1}$) 염 용액을 혼합하여, 상온에서 1년 동안 토양의 성질, 금속의 종류, 금속의 농도에 따른 용해도 변화관찰을 시도하였다. 그 결과, 히스토졸에서는 카드뮴이, 앤디졸에서는 구리가, 미세입자 알피졸에서는 아연이 가장 높은 분배 계수를 보였고, 옥시졸과 조대입자 알피졸에서는 모든 금속들이 가장 낮은 분배 계수를 나타내었다. 또한, 카드뮴과 아연의 경우 토양의 종류와는 무관하게 시간에 따른 분배 계수의 증가를 보였지만, 구리의 경우 토양 내 유입된 후 일주일 부터는 이러한 경향성를 찾아보기 어려웠다. 구리는 토양의 유기물이 많을 경우에는 빠른 흡착성을 보이지만, 토양수에 녹아있는 유기물이 많을 경우에는 그 흡착 특성이 제한됨을 관찰하였다. 더욱이, 흡수력이 높은 토양의 경우 금속의 분배 계수는 유입된 금속의 양과는 무관할 뿐만 아니라, 높은 농도로 처리된 토양의 금속 분배 계수가 낮은 농도로 처리된 토양의 분배계수와 유사해지기 까지는 더 오랜 시간이 요구되는 반면, 낮은 흡수력을 가진 토양의 경우에는 시간보다는 금속의 초기 유입양이 분배 계수 결정에 더욱 큰 영향을 미치는 것으로 밝혀졌다. 본 연구를 통해, 토양에 유입된 금속의 용해도 변화는 시간 뿐만 아니라, 토양의 성질, 금속의 종류와 농도에도 상당히 의존함을 입증하였다.

• Archives of Plastic Surgery
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• 제35권5호
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• pp.581-588
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• 2008

Purpose: It is generally accepted that anatomical structures of the soft tissue in Asian faces are quite different from those in Caucasian. It is presumed that these differences are due to collagen rich thick dermis and durable superficial musculo-apponeurotic system (SMAS) in Asian. We classified the aging lower eyelids and reviewed the operative procedures according to the types of aging lower eyelids in Asian. Methods: We compared preoperative and postoperative photos of 117 patients over 30 years of age, who underwent lower blepharoplasty at the Kyunghee Medical Center from January 2001 to April 2006. We classified the patients based on the degree of skin laxity, presence of nasojugal groove and malar bag, the extent of aging process. We also reviewed the operative procedures according to each type of classification. Results: We classified our patients into four types as following. Type I patients showed minimal skin-muscle excess confined to lower eyelids regardless of the facial line. For these patients, we performed only transcutaneous or transconjunctival blepharoplasty. In type II patients, nasojugal grooves were shown and skin- muscle laxity was limited to the medial side of imaginary vertical line at lateral margin of pupil. In these cases, we performed free fat graft or fat repositioning on nasojugal groove or fat removal and septal duplication confined to medial side. Type III patients displayed more advanced medial bulging and remarkable laxity over the lateral side, the same operation methods as those of type II were applied at the lateral side of the line. Type IV patients demonstrated extensive midfacial aging changes including malar bags and underwent superficial subciliary cheek lift. Conclusion: The lower eyelid aging of Asian is different from those of Caucasian. We think that our classification is useful in selection of appropriate operative procedure to address specific problems for Asian patients.

• Elastomers and Composites
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• 제44권4호
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• pp.442-446
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• 2009

충전제의 영향을 막기 위해 비보강 NR, BR, SBR 고무 가황물을 원형 변형시켜 노화시킨 후 회복 거동을 비교하였다. 시료는 상온, 50, 70, $90^{\circ}C$에서 10일간 노화시켰다. 측정 시간이 증가함에 따라 회복률은 증가하였다. 노화 후 측정 시간에 따른 회복률의 변화로부터 1.0 초 미만의 순간회복률을 구하였다. 상온 노화에서는 노화 기간이 짧아 고무 간의 회복률 차이가 거의 나타나지 않았다. 하지만 50, 70, $90^{\circ}C$에서의 가속 노화 실험 결과에서는 각 고무 간의 회복률 차이가 뚜렷하게 나타났다. BR의 회복률이 가장 우수하였고, SBR의 회복률이 가장 적었다. 그러나 $90^{\circ}C$ 가속 노화 에서는 NR의 회복률이 BR보다 높게 나타났다. 노화 온도가 높아 질수록 초기 회복률이 감소하였으며, 그 감소 폭은 SBR이 가장 크게 나타났다. 실험 결과는 고무의 반발 특성과 노화에 의한 가교밀도 변화로 설명하였다.

• 한국노년학
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• 제37권2호
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• pp.329-347
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• 2017

본 연구의 목적은 강화도 지역 노인의 신체적, 정신적 건강과 인간관계 크기를 설명해주는 사회연결망 연결정도가 관련성이 있는지를 분석하여 노년기의 사회적 관계가 지역사회 노인의 건강을 예측할 수 있는지를 알아보고자 하는 것이다. 연구대상은 강화도 A군에 거주하는 65세 이상 남녀 노인 643명으로, 2011년에서 2012년까지 실시된 "한국인의 사회적 삶, 건강과 노화에 대한 조사(KSHAP; Korean Social Life, Health and Aging Project)" 1년차 자료를 사용하여 위계적 회귀분석을 실시하였다. 분석결과 첫째, 통제변인으로 사용한 인구통계학적 변인 중에서 성별, 소득, 연령은 노인의 신체적 건강과 상관관계를 보이는 것으로 나타났다. 남성이 여성보다, 소득이 높을수록, 연령이 낮을수록 신체적 건강이 더 좋은 것으로 나타났다. 둘째, 인구통계학적 변인 중에서 학력, 소득, 연령은 정신적 건강과 상관관계를 보이는 것으로 나타났다. 학력이 높을수록, 소득이 높을수록, 연령이 낮을수록 정신적 건강이 더 좋은 것으로 나타났다. 셋째, 방향이 포함된 사회연결망에서 외향연결정도와 내향연결정도 모두 노인의 신체적, 정신적 건강을 예측하는 것으로 나타났다. 본 연구결과는 한 개인의 대인관계가 노인의 건강을 예측하는 데 있어 내가 교류한다고 생각하는 사람의 수(외향연결정도) 뿐만 아니라 나와 교류한다고 생각하는 사람의 수(내향연결정도)도 같이 고려할 필요가 있다는 것을 시사하며, 방향에 따른 연결정도의 두 지표가 신체적, 정신적으로 취약할 수 있는 고립된 개인들을 찾아내는데 활용될 수 있다는 점에서 지역사회 노인에 대한 건강 증진 및 복지 차원에서 의미가 있다.

• Architectural research
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• 제14권4호
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• pp.153-161
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• 2012

This paper presents an integrated procedure to predict the temperature and moisture distributions in hardening concrete considering the effects of temperature and aging. The degree of hydration is employed as a fundamental parameter to evaluate hydro-thermal-mechanical properties of hardening concrete. The temperature history and temperature distribution in hardening concrete is evaluated by combining cement hydration model with three-dimensional finite element thermal analysis. On the other hand, the influences of both self-desiccation and moisture diffusion on variation of relative humidity are considered. The self-desiccation is evaluated by using a semi-empirical expression with desorption isotherm and degree of hydration. The moisture diffusivity is expressed as a function of degree of hydration and current relative humidity. The proposed procedure is verified with experimental results and can be used to evaluate the early-age crack of hardening concrete.

• Journal of Oral Medicine and Pain
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• 제17권1호
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• pp.31-39
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• 1992

The authors evaluated the degree of permanent tooth wear in order to make the basic date that are necessary to estimate the age. 10443 teeth of 389 individuals with known age were selected to estimate the degree of tooth wear. The obtained results were as follows : 1. The degree of tooth wear was decreased in males and females with aging. (P<0.001) 2. The degree of tooth wear in males in higher than that of females.(P<0.05) 3. The decision coefficient increased gradually from anterior teeth to posterior teeth.

• 한국약용작물학회지
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• 제14권6호
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• pp.329-335
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• 2006

The present study was designed to investigate aging-related effects on the activities of xenobiotic metabolizing enzymes of rat liver by dietary supplementation of Korean red ginseng water-extract. Rat did not show any discernible signs of the rejection symptoms, and blood GOT and GPT levels were not influenced by ginseng water extracts, Cytochrome 450 levels and NADPH cytochrome P45O reductase, p-450 dependent ethoxycoumarin O-deethylase, and benzphetamine N-demethylase activities were decreased with aging, however, these phase I system enzymes activities in the ginseng group of24 months were well maintained compared with normal group. But, Levels of cytochrome bs and NADH-cytochrome b$_5$ reductase activities were also decreased with aging and were not found a clear difference between two groups. Glutathione-s-transferase activity, phase II enzyme system, in liver cytosols was also decreased in old ages, but the degree of decrease was higher in normal group than in giuseng supplemented group. These results indicate that long-term supplementation of red ginseng water extracts from weaning to 24 months do not show any side effects to rats, and retard age-related deteriorations of xenobiotic metabolizing enzymes activities in old ages.

• The Korean Journal of Physiology and Pharmacology
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• 제1권2호
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• pp.117-125
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• 1997

The N-methyl-D-aspartate (NMDA) receptor-mediated glutamatergic neurotransmission is involved in synaptic plasticity, developmental processes, learning and memory and many neuropathological disorders including age-related diseases. In the present study, regulation of the NMDA receptor properties by various ligands was investigated using $[^3H]MK-801$ binding studies in the synaptic membranes of young and aged rat forebrains. The binding in the presence of glutamate and glycine increased dramatically with growth between 1 and 6 weeks old, and thereafter declined gradually with aging. Glutamate, glycine or spermine respectively increased the binding with growth. Glutamate maintained the binding during aging, while glycine or spermine significantly decreased the binding in the aged brain. The maximum stimulation by glycine varied depending on the ages of brains. Greater sensitivity to glycine was observed at 1 week and 3 months and the sensitivity was significantly reduced in the aged brain. In contrast, spermine showed similar stimulation patterns in young and aged rats. These results indicated that the functional properties of the NMDA receptor-ion channel complex in young and aged rat forebrains are differentially regulated by agonists, and the reduction of the receptor function with normal aging may be, in some degree, due to the reduction of the receptor sensitivity to glycine.

• Journal of Pharmaceutical Investigation
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• 제13권1호
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• pp.1-9
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• 1983

The effect of humidity on crystallization and polymorphic transformation of hydrous aluminum oxide under various humidity at $37^{\circ}$ was examined by means of X-ray diffraction, scanning electron micrograph, IR spectra and DTA. The humidity was an important factor influencing crystallization of hydrous aluminum oxide. The growth or crystal was strongly accelerated by humidity. The aging process is assumed that it is composed of two seperate steps, an increase of the diffraction around $36{\sim}42^{\circ}$, and an appearance and its development of the peak at $18{\sim}20^{\circ}$ of $2{\theta}$ value. The former is considered to be nucleation and the latter correspond to the growth period on crystallization. The crystalline form of aging products was various depending on the degree of humidity, directly it leads to the eventual formation of bayerite in more than 72%, $b{\"{o}}hmite$ in 50% and resembled to Nordstandite in 0% relative humidity, respectively but once formed, it was mostly stable in each surroundings and does not transform to the other more stable form in solid state even after aging for five years. The mechanism responsible for aging is further polymerization process of six-membered rings by deprotonation-dehydration reaction in which positively charged polynuclear hydroxy aluminum complexes formed in the presence of moisture are joined at their edges by double hydroxide bridges.

• 대한화장품학회:학술대회논문집
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• 대한화장품학회 2003년도 IFSCC Conference Proceeding Book I
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• pp.590-600
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• 2003

The matrix metalloproteinases (MMPs) are a family of enzymes responsible for degrading connective tissue. MMPs catalyze the breakdown of collagen from the extracellular matrix, leading to wrinkle formation and accelerated skin aging. Furthermore, ultraviolet irradiation causes increased expression of certain MMPs. In the extracellular matrix turnover, MMPs are interacting with endogenous regulators named tissue inhibitors of metalloproteinases (TIMPs). Using peptide substrate assays, it has been demonstrated that TIMP-MMP complexes interact highly specifically with $K_{i}$ values of 10$^{-9}$ -10$^{-16}$ M. Therefore applications for TIMP as inhibitor of collagen degradation are suggested for cosmetic anti-aging products to prevent wrinkle formation and loss of elasticity. To date four TIMP proteins (TIMP-1, TIMP-2, TIMP-3 and TIMP-4) have been identified which show a high degree in sequence similarity. The production of human TIMP-2, a 194-residue nonglycosylated protein, was performed by fed-batch culture of Escherichia coli. TIMP-2 accumulated in the bacterial cells in an insoluble form as inclusion bodies. The inclusion bodies were solubilized and the protein refolded to yield the native TIMP-2 in the active form. The integrity of the protein was confirmed by mass analysis, Edman sequencing and gel shift experiments with authentic samples. The inhibitory activity of the refolded and purified TIMP-2 was demonstrated with MMP-1 and MMP-2 assays using synthetic fluorogenic peptide substrates.s.