• Journal of Life Science
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• v.21 no.3
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• pp.464-467
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• 2011

Quercetin is a major flavonoid present in onions, which acts as an antioxidant. Quercetin exists both as a free compound and conjugated with carbohydrates, primarily as glucosides in onion. Aged black onion was made through a 30 day aging process in which the onions were kept in an environment of $60^{\circ}C$ and high humidity (90% RH). Quercetin and quercetin glucosides were assayed in onion bulbs before and after the aging process, using high performance liquid chromatography-electrospray ion trap mass spectrometry (HPLC-ESI/MS/MS). Quercetin mono- and diglucosides were identified in fresh onion bulbs, whereas quercetin aglycone was the only form present in aged black onion bulbs. These findings indicate that the quercetin mono- and di-glucosides present in fresh onions undergo complete deglycosylation during the aging process. Such profiling will provide a rapid method that can be used to assess changes in the two major quercetin glycosides during the aging process of onion bulbs.

• Proceedings of the Korean Nutrition Society Conference
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• 1994.07a
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• pp.663-665
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• 1994

• Biomolecules & Therapeutics
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• v.23 no.3
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• pp.290-295
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• 2015

Aging is defined as a collective process that alters organism's functional capacity and appearance over the course of life. Apart from an increase in susceptibility to many diseases, aging affects the cellular system that is responsible for decoding painful stimuli. Yet, aging-associated molecular mechanisms of pain perception remains elusive. Using Drosophila, we showed a decrease in temperature tolerance and a reduction in high temperature thermal avoidance with aging. Locomotor activity assay demonstrated that the age-dependent changes in heat nociception did not stem from the general decline in muscular activity. However, we identified pain-related gene expression alteration with aging. We anticipate that our findings would help opening a new window onto developing the optimal pain treatment for the elderly.

• BMB Reports
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• v.52 no.2
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• pp.111-112
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• 2019

Although many studies have reported that the breakdown of the blood-brain barrier (BBB) represents one of the major pathological changes in aging, the mechanism underlying this process remains relatively unexplored. In this study, we described that acid sphingomyelinase (ASM) derived from endothelial cells plays a critical role in BBB disruption in aging. ASM levels were elevated in the brain endothelium and plasma of aged humans and mice, resulting in BBB leakage through an increase in caveolae-mediated transcytosis. Moreover, ASM caused damage to the caveolae-cytoskeleton via protein phosphatase 1-mediated ezrin/radixin/moesin dephosphorylation in primary mouse brain endothelial cells. Mice overexpressing brain endothelial cell-specific ASM exhibited acceleration of BBB impairment and neuronal dysfunction. However, genetic inhibition and endothelial specific knock-down of ASM in mice improved BBB disruption and neurocognitive impairment during aging. Results of this study revealed a novel role of ASM in the regulation of BBB integrity and neuronal function in aging, thus highlighting the potential of ASM as a new therapeutic target for anti-aging.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.12
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• pp.51-56
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• 2018

Due to the aging of economically active population in the world, the average age of workers in the domestic construction industry is also steadily increasing. This study analyzes the aging of construction workers in small-size construction sites in Busan, where the aging of the economically active population is the most severe in Korea. As a result of the study on the aging of construction workers in six construction sites with a construction cost of less than 500 million won in Busan, it was found that 65% of the workers were over 50 years of age. In addition, several experts interviews and survey revealed that 'securing welfare facilities for construction workers' and 'diminishing prejudice about the construction industry" were the most urgent and effective methods to overcome the aging problems. The results of this study can be served as basic data to solve the aging problems in the industry.

• Korean Journal of Metals and Materials
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• v.49 no.6
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• pp.448-453
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• 2011

Pre-aging heat treatment after solution heat treatment (SHT) of Al-0.4 wt%Mg-1.2 wt%Si-0.1 wt%Mn alloy sheets for auto-bodies was carried out to investigate the effect of pre-aging and its conditions on the bake-hardening response. Mechanical properties were evaluated by a tensile and Vickers hardness test. Microstructural observation was also performed using a transmission electron microscope (TEM). It was revealed that pre-aging treatments play a great role in the bake-hardening response. In addition, it was found that the sphere-shaped nanosized clusters that can directly transit to the needle-shaped ${\beta}$" phase during the paint-bake process, not being dissolved into the matrix, are formed at 343 K. The result, reveals that the dominant factor of the bake-hardening response is the pre-aging temperature rather than the pre-aging time.

• IMMUNE NETWORK
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• v.1 no.2
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• pp.104-108
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• 2001

Aging is a senescence and defined as a normal physiologic and structural alterations in almost all organ systems with age. As Leonard Hayflick, one of the first gerontologists to propose a theory of biologic aging, indicated that a theory of aging or longevity satisfies the changes of above conditions to be universal, progressive, intrinsic and deleterious. Although a number of theories have been proposed, it is now clear that cell aging (cell senescence) is multifactorial. No single mechanism can account for the many varied manifestations of biological aging. Many theories have been proposed in attempt to understand and explain the process of aging. Aging is effected in individual by genetic factors, diet, social conditions, and the occurrence of age-related diseases as diabetes, hypertension, and arthritis. It involves an endogenous molecular program of cellular senescence as well as continuous exposure throughout life to adverse exogenous influences, leading to progressive infringement on the cell's survivability so called wear and tear. So we could say the basic mechanism of aging depends on the irreversible and universal processes at cellular and molecular level. The immediate cause of these changes is probably an interference in the function of cell's macromolecules-DNA, RNA, and cell proteins-and in the flow of information between these macromolecules. The crucial questions, unanswered at present, concerns what causes these changes in truth. Common theories of aging are able to classify as followings for the easy comprehension. 1. Biological, 1) molecular theories - a. error theory, b. programmed aging theory, c. somatic mutation theory, d. transcription theory, e. run-out-of program theory, 2) cellular theories - a. wear and tear theory, b. cross-link theory, c. clinker theory, d. free radical theory, e. waste product theory, 3) system level theory-a. immunologic/autoimmune theory, 4) others - a. telomere theory, b. rate of living theory, c. stress theory, etc. Prevention of aging is theoretically depending on the cause or theory of aging. However no single theory is available and no definite method of delaying the aging process is possible by this moment. The most popular action is anti-oxidant therapy using vitamin E and C, melatonin and DHEA, etc. Another proposal for the reverse of life-span is TCP-17 and IL-16 administration from the mouse bone marrow B cell line study for the immunoglobulin VDJ rearrangement with RAG-1 and RAG-2. Recently conclusional suggestion for the extending of maximum life-span thought to be the calory restriction.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.613-618
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• 2002

Steel slag produced in steel making process is divided with electric arc furnace slag and converter slag. Compared with the blast furnace slag, converter slag has the expansibility due to the reaction with water and free CaO. Therefore it is specified in Standard Specification for Concrete in Korea that steel slag aggregate must not be used in concrete. In this study, we treat electric arc furnace slag aggregate(EAFSA) for concrete before and after several aging process to reduce expansibility. The fundamental properties are measured, which are specific gravity, unit weight, abrasion value and immersion expansion ratio, as concrete aggregate. To understand the suitability of EAFSA for concrete, we made the concrete with EAFSA and then determined the strength and the volume change in EAFSA concrete. From the results EAFSA treated with steam aging process has potentiality for concrete aggregate.

• Journal of the Korean Ceramic Society
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• v.52 no.5
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• pp.366-373
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• 2015

Sol-gel binder was prepared by hydrolysis and condensation reaction using boehmite sol and methyltrimethoxysilane as a function of aging-time. The coating slurry was composed of a plate-shape alumina in the sol-gel binder for the EPD process, in which particles dispersed in the slurry were deposited on the electrode under an electric field due to the surface charge. We studied the effects of three parameters: the content of boehmite, the aging time, and the applied voltage, on the physical, thermal, and electrical properties of the hybrid composite films by EPD. The amount of boehmite was 10 ~ 20 wt% and the aging time was 0.5 ~ 72, with a fixed amount of plate-shape alumina of 10 wt%. The condition of applied voltage was 5 ~ 30 V with a distance of 2 cm between the electrode during the EPD process. We confirmed that a structure of hybrid composite films of well-ordered plate alumina was deposited on the substrate when the film was prepared using a sol-gel binder composed of 15 wt% boehmite with 1 hr aging time and EPD at 10 V. The process shows a weight loss of 7% at $500^{\circ}C$ in TGA and a breakdown voltage of 8 kV at $87{\mu}m$.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.5 no.3
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• pp.278-283
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• 1995

The potassium titanate fibres were synthesized with wet process by the addition of KOH solution to the TiOz gel produced by the reaction between element titanium particles and $H_2O_2$ solution at $50^{\circ}C$. And then they were characterized by XRD, SEM and FT - IR. It was found that potassium titanate fibres were mainly affected by KOH/TiOz mole ratio, synthesis time and aging time in this wet process employed. For $KOH/TiO_2 = 1/1$, synthesizing time 24 hrs, aging time 24 hrs and calcination temperature of TEX>$900^{\circ}C$ for 1 hr, their products were mainly found to be potassium tetratitanate which had thin and long fibres in the range of 10 ~ 20 mm. As the synthesizing time increased and the amount of KOH decreased, potassium tetratitanate was converted into potassium hexatitanate. Also, the length of their fibres became short.