• 펄프종이기술
• /
• 제43권3호
• /
• pp.66-72
• /
• 2011

The annals of Joseon Dynasty is one of UNESCO's Memory of the World Register. For the safety preservation of the waxed annals of Joseon Dynasty, the acidic and alkaline aging mechanism of beeswax and beeswaxed Hanji has been investigated. The weight loss of beeswaxed Hanji by the acidic aging was higher than those of alkaline beeswax. The acid value and relative intensity of carbonyl groups in beeswax were slowly increased with aging time. The strength of dewaxed Hanji was decreased with aging time. The significant changes of crystallinity of dewaxed Hanji by acidic and alkaline aging were not observed.

• 센서학회지
• /
• 제26권4호
• /
• pp.292-296
• /
• 2017

It has become ever harder to design reliable circuits with each nanometer technology node under normal operation conditions, a transistor device can be affected by various aging effects resulting in performance degradation and eventually design failure. The reliability (aging) effect has traditionally been the area of process engineers. However, in the future, even the smallest of variations can slow down a transistor's switching speed, and an aging device may not perform adequately at a very low voltage. Because of such dilemmas, the transistor aging is emerging as a circuit designer's problem. Therefore, in this paper, the impact of aging effects on the delay and power dissipation of digital circuits by using nanomneter MOSFET power gating structure has been analyzed.. Based on this analyzed aging models, a reliable digital circuits can be designed.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제14권1호
• /
• pp.124-130
• /
• 2014

In highly reliable and durable systems, failures due to aging might result in catastrophes. Aging monitoring techniques to prevent catastrophes by predicting such a failure are required. This paper presents a scan-based on-line aging monitoring scheme which monitors aging during normal operation and gives an alarm if aging is detected so that the system users take action before a failure occurs. We illustrate our modified scan chain architecture and aging monitoring control method. Experimental results show our simulation results to verify the functions of the proposed scheme.

• BMB Reports
• /
• 제54권5호
• /
• pp.253-259
• /
• 2021

Aging is characterized by a functional decline in most physiological processes, including alterations in cellular metabolism and defense mechanisms. Increasing evidence suggests that caloric restriction extends longevity and retards age-related diseases at least in part by reducing metabolic rate and oxidative stress in a variety of species, including yeast, worms, flies, and mice. Moreover, recent studies in invertebrates - worms and flies, highlight the intricate interrelation between reproductive longevity and somatic aging (known as disposable soma theory of aging), which appears to be conserved in vertebrates. This review is specifically focused on how the reproductive system modulates somatic aging and vice versa in genetic model systems. Since many signaling pathways governing the aging process are evolutionarily conserved, similar mechanisms may be involved in controlling soma and reproductive aging in vertebrates.

• BMB Reports
• /
• 제56권2호
• /
• pp.49-55
• /
• 2023

Aging is characterized by a gradual decline in biological functions, leading to the increased probability of diseases and deaths in organisms. Previous studies have identified biological factors that modulate aging and lifespan, including non-coding RNAs (ncRNAs). Here, we review the relationship between aging and tRNA-derived small RNAs (tsRNAs), ncRNAs that are generated from the cleavage of tRNAs. We describe age-dependent changes in tsRNA levels and their functions in age-related diseases, such as cancer and neurodegenerative diseases. We also discuss the association of tsRNAs with aging-regulating processes, including mitochondrial respiration and reduced mRNA translation. We cover recent findings regarding the potential roles of tsRNAs in cellular senescence, a major cause of organismal aging. Overall, our review will provide useful information for understanding the roles of tsRNAs in aging and age-associated diseases.

• 한국노년학
• /
• 제39권1호
• /
• pp.37-60
• /
• 2019

이 연구는 한국 노인들의 노화과정을 추적해 노화의 궤적을 도출하고, 그 특성을 파악하고자 시도된 것이다. 특별히 연구는 Rowe와 Kahn이 제시한 성공노화모델을 분석틀로 삼고, 집단중심 다중궤적모형을 활용해 귀납적 방식으로 노화궤적을 도출하였다. 또한 주요 인구사회적 특성들을 기본 예측요인으로 삼아 각 노화궤적의 특성들을 다항로지스틱 분석으로 파악하고자 했다. 분석을 위해 활용된 자료는 고령화연구패널(KLoSA)의 1~6차 조사자료이며, 분석대상은 65세이상 74세이하의 전기노인 2,682명이다. 다중궤적모형에 활용된 분석지표는 만성질환, 신체기능, 인지기능, 우울증상, 그리고 사회참여활동이다. 분석을 통해 도출된 노화궤적은 5개이며, 각각은 5개 지표의 변화양상에 따라 일반노화군(33.9%), 경도인지장애동반군(22.1%), 건강기능저하군(18.2%), 성공노화군(17.8%), 병적노화군(7.9%)로 명명되었다. 한편, 다항로지스틱분석을 실시한 결과 일반적으로 성공 노화는 남성, 저연령, 고학력, 고소득, 유배우자 집단이 경험할 가능성이 컸다. 반면, 저학력, 저소득, 그리고 고연령의 경우 상대적으로 어려운 노화의 과정을 겪을 가능성이 컸다. 특히, 경도인지장애동반노화를 겪을 가능성은 배우자가 없는 저학력, 저소득, 그리고 고연령 여성에게서 크게 나타났다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제30권2호
• /
• pp.254-261
• /
• 2017

Objective: The effects of aging and freezing/thawing sequence on color, physicochemical, and enzymatic characteristics of two beef muscles (Mm. gluteus medius, GM and biceps femoris, BF) were evaluated. Methods: Beef muscles at 3 d postmortem were assigned to four different combinations of aging and freezing/thawing sequence as follows; aging at $2^{\circ}C$ for 3 wk (A3, never-frozen control), freezing at $-28^{\circ}C$ for 2 wk then thawing (F2, frozen/thawed-only), aging at $2^{\circ}C$ for 3 wk, freezing at $-28^{\circ}C$ for 2 wk then thawing (A3F2), and freezing at $-28^{\circ}C$ for 2 wk, thawing then further aging at $2^{\circ}C$ for 3 wk (F2A3). Results: No significant interactions between different aging/freezing/thawing treatments and muscle type on all measurements were found. Postmortem aging, regardless of aging/freezing/thawing sequence, had no impact on color stability of frozen/thawed beef muscles (p<0.05). F2A3 resulted in higher purge loss than F2 and A3F2 treatments (p<0.05). A3F2 and F2A3 treatments resulted in lower shear force of beef muscles compared to F2 (p<0.05). Although there was no significant difference in glutathione peroxidase (GSH-Px) activity, F2A3 had the highest ${\beta}-N-acetyl$ glucominidase (BNAG) activity in purge, but the lowest BNAG activity in muscle (p<0.05). GM muscle exhibited higher total color changes and purge loss, and lower GSH-Px activity than BF muscle. Conclusion: The results from this present study indicate that different combinations of aging/freezing/thawing sequence would result in considerable impacts on meat quality attributes, particularly thaw/purge loss and tenderness. Developing a novel freezing strategy combined with postmortem aging will be beneficial for the food/meat industry to maximize its positive impacts on tenderness, while minimizing thaw/purge loss of frozen/thawed meat.

• 한국식품과학회지
• /
• 제39권5호
• /
• pp.584-587
• /
• 2007

치환도를 달리한 하이드록시프로필화 쌀전분의 동적 레올로지 특성이 소변형 진동측정방법(small-deformation oscillatory measurement)에 의해 관찰되었다. Aging 전 $4^{\circ}C$에서 측정된 저장탄성률 G#과 손실탄성률 G"의 값은 치환도(0.030-0.118)가 증가함에 따라 증가하였으며, 반면에 tan ${\delta}5(G"/G#)$는 감소하였다 $4^{\circ}C$에서 10시간 aging하는 동안 하이드록시프로필화 쌀전분의 G#값은 초기 단계에서 급속히 증가한 다음 곧 바로 2시간이내에 안정기(plateau) 영역에 도달하였다. 그러나 천연전분(native starch)은 10시간 동안의 aging후에도 안정기 영역이 관측되지 않았다. 치환도의 증가는 하이드록시프로필화 쌀전분의 안정기 G#값의 감소를 초래하였다. Aging하는 동안의 구조전개 속도상수 K는 1차 kinetics식으로부터 얻어졌으며, 하이드록시프로필화 쌀전분의 K값은 높은 치환도에서 낮은 수치를 보여주었다.

• Journal of Electrical Engineering and Technology
• /
• 제13권6호
• /
• pp.2412-2420
• /
• 2018

The thermal degradation of low density polyethylene (LDPE) will accelerate the production of carbonyl groups (C=O), which can act as the induced dipoles under high voltage. In this paper, we researched the dielectric properties and space charge behavior of LDPE after thermal aging, which can help us to understand the correlation between carbonyl groups (C=O) and electrical properties of LDPE. The spectra results show that LDPE exhibit obvious thermooxidative reactions when the aging time is 35 days and the productions mainly contain carboxylic acid, carboxylic eater and carboxylic anhydride, whose amount increase with the increasing of aging time. The dielectric properties show that the real permittivity of LDPE is inversely proportional to temperature before aging and subsequently become proportional to temperature after thermal aging. Furthermore, both the real and imaginary permittivity increase sharply with the increasing of aging time. The fitting results of imaginary permittivity show that DC conductivity become more sensitive about temperature after thermal aging. On this basis, the active energies of materials calculated from DC conductivity increase first and then decrease with the increasing of aging time. In addition, the space charge results show that the heterocharges accumulated near electrodes in LDPE change to the homocharges after thermal aging and the mean volume charge density increase with the increasing of aging time. It is considered that the overlaps caused by electrical potential area is the main reason for the increase of DC conductivity.

• 한국연초학회지
• /
• 제26권1호
• /
• pp.35-42
• /
• 2004

This study was carried out to examinate the effect of aging period on chromatic, chemical and organoleptic characteristics, and to evaluate of optimum aging period for each grade in burley leaf tobacco. The leaf tobaccos were produced in 2000, and threshed, redried and packed in carton box under the current methods. Four grades of processed leaf(A3T, B1T, C1W and D3W) were stored during 24 months (May 10, 2001 to April 31, 2003) in warehouse of Chungju Leaf Tobacco Processing Factory. The leaf tobaccos were sampled at three month intervals for analysis of chromatic, chemical and organoleptic properties. pH values of four grades, and Yellow(b) of A3T and BIT were also significantly decreased during the aging. Filling values, tar, nicotine and CO contents of tobacco smoke, and puff number of cigarettes were not significantly changed during the aging. Positive correlation coefficients were significantly observed between irritation of the calculated attributes from contents of volatile oil components in leaf tobacco and that of the panel sensory attributes. The ratio of maximum change in irritation attribute was larger than that in taste attribute during aging. The calculated irritations of 18～24 months aging for A3T and B1T were significantly lower than zero-aging, while those of C1W and D3W were not significant among aging periods. The panel irritations of 12～15 months aging for four grades were low tendency. The results suggest that decrease of aging period for thin leaf from 21～24 to 12～15 months may be beneficial to save storage cost in burley tobacco.