• Korean Journal of Pharmacognosy
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• v.50 no.4
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• pp.285-290
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• 2019

This study was carried out to identify the skin anti-aging effect of cycloheterophyllin on dermal fibroblasts. To elucidate anti-aging effects of cycloheterophyllin on dermal fibroblasts, I measured cell viability, mRNA expressions, and Collagen, type I/matrix metallopeptidase 1(MMP1)-ELISA assay. In this study, I investigated the effects of cycloheterophyllin on Collagen, type I, alpha 1(COL1A1)/Collagen, type III, alpha 1(COL3A1)/MMP1/Superoxide dismutases/Catalase(CAT) mRNA expressions and Collagen, type I/MMP1 protein production. Quantitative Real-time RT-PCR showed that cycloheterophyllin increased mRNA level of COL1A1/COL3A1/CAT genes and collagen, type I protein by ELISA assay compared to UVA-treated dermal fibroblasts. Furthermore MMP1 mRNA and protein expressions were decreased by cycloheterophyllin treatment. These observations revealed that cycloheterophyllin increased anti-aging effects in dermal fibroblasts. Therefore, I identified the anti-aging effects of cycloheterophyllin, and these results showed that the cycloheterophyllin can be a considerable potent ingredient for skin anti-aging. Based on this, I anticipated further researches about cycloheterophyllin for mechanism to develop not only cosmetics but for healthcare food or medicine.

• Journal of Power System Engineering
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• v.15 no.6
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• pp.73-80
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• 2011

The experimental investigation focuses on an influence of artificial aging time in longitudinal butt welded Al 6013-T4 aluminum alloy on the fatigue crack growth resistance. The preferred welding processes for this alloy are frequently tungsten inert gas welding (TIG) process due to its comparatively easier applicability and better weldability than other gas metal arc welding. Fatigue crack growth tests were carried out on compact tension specimens (CT) in longitudinal butt TIG welded after T82 heat treatment was varied in three artificial aging times of 6 hours, 18 hours and 24 hours. Of the three artificial aging times, 24 hours of artificial aging time are offering better resistance against the growing fatigue cracks. The superior fatigue crack growth resistance preferred spatial variation of materials within each specimen in the Paris equation based on reliability theory and fatigue crack growth rate by crack length are found to be the reasons for superior fatigue resistance of 24 hours of artificial aging time was compared to other joints. The highest of crack propagation resistance occurs in artificial aging times of 24 hours due to the increase in grain size (fine grained microstructures).

• BMB Reports
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• v.52 no.1
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• pp.47-55
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• 2019

Cellular senescence (CS) is one of hallmarks of aging and accumulation of senescent cells (SCs) with age contributes to tissue or organismal aging, as well as the pathophysiologies of diverse age-related diseases (ARDs). Genetic ablation of SCs in tissues lengthened health span and reduced the risk of age-related pathologies in a mouse model, suggesting a direct link between SCs, longevity, and ARDs. Therefore, senotherapeutics, medicines targeting SCs, might be an emerging strategy for the extension of health span, and prevention or treatment of ARDs. Senotherapeutics are classified as senolytics which kills SCs selectively; senomorphics which modulate functions and morphology of SCs to those of young cells, or delays the progression of young cells to SCs in tissues; and immune-system mediators of the clearance of SCs. Some senolytics and senomorphics have been proven to markedly prevent or treat ARDs in animal models. This review will present the current status of the development of senotherapeutics, in relation to aging itself and ARDs. Finally, future directions and opportunities for senotherapeutics use will discussed. This knowledge will provide information that can be used to develop novel senotherapeutics for health span and ARDs.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.313-316
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• 2008

This work sought to examine the suitability of twin roll strip casting for Ag-27%Cu-25%Zn-3%Sn brazing alloy (BAg-7A) and to investigate the mechanical properties and microstructure of the strip. The effect of aging heat treatment on the properties was also studied,. This new manufacturing process has applications in the production of the brazing alloy. XRD and microstructural analysis of the Ag-27%Cu-25%Zn-3%Sn strip represented eutectic microstructure of a Cu-rich phase and a Ag-rich matrix regardless of heat treatment. The results of mechanical tests showed tensile strength of 470MPa, a significant enhancement, and an 18% elongation of the twin roll casted strip, due mainly to the solid solution strengthening of Zn atoms (${\sim}20%$) in the Cu-rich phases. Tensile results showed gradually decreasing strengths and increasing elongation with aging heat treatment. Microstructural evolution and fractography were also investigated and related to the mechanical properties.

• Corrosion Science and Technology
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• v.14 no.6
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• pp.313-324
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• 2015

Austenitic stainless steels have been widely used in many engineering fields because of their high corrosion resistance and good mechanical properties. However, welding or aging treatment may induce intergranular corrosion, stress corrosion cracking, pitting, etc. Since these types of corrosion are closely related to the formation of chromium carbide in grain boundaries, the alloys are controlled using methods such as lowering the carbon content, solution heat treatment, alloying of stabilization elements, and grain boundary engineering. This work focused on the effects of aging and UNSM (Ultrasonic Nano-crystal Surface Modification) on the intergranular corrosion of commercial 316L stainless steel and the results are discussed on the basis of the sensitization by chromium carbide formation and carbon segregation, residual stress, grain refinement, and grain boundary engineering.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.2
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• pp.43-56
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• 2008

The purpose of the experiment was to evaluate the material stability of the paper of the annals of Joseon Dynasty for the conservation purpose and the categories were as listed below : 1. Procuring traditional Hanji and semi-Hanji from different regional hanji paper mill. 2. Artificial accelerated aging treatment to examination its stability (UV irradiation, dry heat) 3. Analysis of optical, physical characteristic. The suitable Hanji for categories would be used as a reconstruction material for the waxel paper in the papers of the annals of Joseon Dynasty.

• Fashion & Textile Research Journal
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• v.16 no.3
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• pp.456-461
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• 2014

The objective of this study is to give PP(polypropylene) fabric a good affinity for water. Oxygen plasma was treated to PP fabrics in a commercial glow discharge reactor with different RF power, discharge pressure, and reaction time. The PP fiber surfaces were characterized by the measurement of contact angle and ESCA. A JEOL scanning electron microscope was used to observe the surface morphology of fibers. The spontaneous water uptake amount of PP fabrics was determined by the demand wettability test. To determine the effect of aging on the surface properties of $O_2$ plasma treated PP, all the above measurements of the samples were carried out after 1, 7, 30, 60, and 150 days. The results are as follows. The PP fiber surfaces treated by $O_2$ plasma treatment have a chemical composition that consisted of various oxygen containing polar groups. Consequently, the contact angles of the treated PP fibers decreased, which improved the water uptake rate of PP fabrics. Surface roughness of the treated PP affected the fabric wettabiity as well. Wettability of the treated PP decreased and leveled off with aging. The $O_2$ plasma treatment is a simple and effective method to increase the water uptake rate of PP fabrics.

• Biomedical Science Letters
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• v.7 no.3
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• pp.111-116
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• 2001

To investigate an effect of aging on the xylene metabolism in liver damaged animals, a study was conducted. 50% carbon tetrachloride ($CCl_4$) in olive oil (0.1 ml/100 g body weight) was intraperitoneally given to 5-week and 12-week rats 12 times every other day and then one dose of 50% xylene in olive oil (0.25 ml/100 g body weight) was intraperitoneally given to the rats, and after 24 hr, the animals were sacrificed. On the basis of the functional findings in rat liver, ie, serum levels of alanine aminotransferase activity, liver protein and malonedialdehyde contents, 5-week rats showed less liver damage than 12-week rats. The increasing rate of urinary methylhippuric acid concentration to the control was significantly higher in 5-week rats than 12-week rats in case of xylene treatment after induction of liver damage. On the other hand, liver damaged 5-week rats showed significant rise of hepatic cytochrome P45O content compared with the liver damaged 12-week rats by the xylene treatment. And increasing rate of hepatic alcohol or aldehyde dehydrogenase activities to each liver damaged animals was higher tendency in 5-week rats than 12-week rats by the xylene treatment. In conclusion, 5-week rat showed greater metabolic rate of xylene than 10-week rats in case of liver injury because 5-week rats led to a slight liver damaged compared with 12-week rats.

• Journal of Advanced Marine Engineering and Technology
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• v.27 no.3
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• pp.453-459
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• 2003

In this study, the effect of heat treatment to the electrochemical polarization resistance for the Ti-6Al-4V alloy was measured. The solution heat treatments were carried out at $1066^{circ}E, 966^{\circ}$E$, followed by aging heat treated $550^{circ}E, 600^{circ}E, and 650^{circ}E$. The electrochemical polarization resistance behavior was measured by potentio-dynamic polarization in the 1N $HNO_3$ + 15ppm HF solution. The obtained results were as follows. 1. As solution heat temperature increased. the corrosion potential was increased, whereas passive current density and critical current density were decreased. 2. As aging heat temperature increased, the corrosion potential was almost constant, but passive current density was decreased 3. The results of composition test measured by EDS at grain boundary and near $\gamma'$ precipitates indicated that S, Cl. and Si which originated from base metal were segregated at the grain boundaries Al and Ti which were the main alloying element in $\gamma'$ were depleted at the $\gamma'$ precipitated. The depletion of Al and Ti in $\gamma'$ was caused to early breakdown of passive film.

• Journal of the Korean Society for Heat Treatment
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• v.13 no.3
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• pp.177-182
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• 2000

The effects of betatizing and aging temperatures on the martensitic transformation characteristics in an Cu-13.4wt%Al-4.2wt%Ni single crystal have been studied. Microstructures show that the specimen betatized above $800^{\circ}C$ has only ${{\beta}_1}^{\prime}$ martensite while the specimen betatized of below $700^{\circ}C$ has two phases i.e., ${{\beta}_1}^{\prime}+{\gamma}_2$ When betatizing temperature increase from $600^{\circ}C$ upto $900^{\circ}C$, Ms and As temperatures decrease due to the dissolution of which ${\gamma}_2$ phase depletes Al content in the matrix thereafter makes the both Ms and As temperatures significantly increased. Ms and As temperatures of the specimen aged at $200^{\circ}C$ are relatively stable but those of the specimen aged at $300^{\circ}C$ are shifted rapidly with aging time, especially within the first 30min.