• Molecules and Cells
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• v.39 no.9
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• pp.680-686
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• 2016

Uncoupling proteins (UCPs) are mitochondrial inner membrane proteins that function to dissipate proton motive force and mitochondrial membrane potential. One UCP has been identified in Caenorhabditis elegans (C. elegans), namely UCP-4. In this study, we examined its expression and localization using a GFP marker in C. elegans. ucp-4 was expressed throughout the body from early embryo to aged adult and UCP-4 was localized in the mitochondria. It is known that increased mitochondrial membrane protential leads to a reactive oxygen species (ROS) increase, which is associated with age-related diseases, including neurodegenerative diseases in humans. A ucp-4 mutant showed increased mitochondrial membrane protential in association with increased neuronal defects during aging, and the neurons of ucp-4 overexpressing animals showed decreased neuronal defects during aging. These results suggest that UCP-4 may be involved in neuroprotection during aging via relieving mitochondrial membrane protential. We also investigated the relationship between UCP-4 and innate immunity because increased ROS can affect innate immunity. ucp-4 mutant displayed increased resistance to the pathogen Staphylococcus aureus compared to wild type. The enhanced immunity in the ucp-4 mutant could be related to increased mitochondrial membrane protential, presumably followed by increased ROS. In summary, UCP-4 might have an important role in neuronal aging and innate immune responses through mediating mitochondrial membrane protential.

• JOURNAL OF ELECTRICAL WORLD
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• no.8 s.128
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• pp.6-9
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• 1987

• The Korean Journal of Food And Nutrition
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• v.6 no.3
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• pp.219-230
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• 1993

This research aims to study the changes In gastrointestinal function attributed to aging In human. The thresholds for recognition and detection of flavors became elevated and salivary gland acinar cells decreased in the old age. But most esophageal function remained relatively Intact. Although gastric emptying time has been slowed with aging, the total intestinal transit time did not differ. Atropic gastritis due to H. pylori in old man decreased secretion of acid and Intrinsic factor and absorbability of calcium and iron. Pancreatic secretion is droned in older persons. Prevalence of gallstones rised with age. Liver size and portal blood flow decreased significantly with age. Mucosal surface area has been reported to be slightly diminished in the aging man. Glucose transporters decreased and Insulin tolerance Increased. Absorption of aromatic amino acid is diminished with age. Dietary protein In that aging human increased fecal nitrogen excretion. Vitamin A tolerance increased. Vitamin D receptor concentration decreased and resistance to 1,25-(OH)2D3 action increased. Permeability of aging small Intestine Increased. Zinc balance dirt not differ Copper absorption appeared not to be significantly affected by age. Neurotensin secretion decreased thus slowed colonic peristaltic movements and Intestinal mucosal growth.

• Corrosion Science and Technology
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• v.2 no.2
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• pp.75-81
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• 2003

Chromium, molybdenum. and nitrogen are very important alloying elements in stainless steels and its effect was approved in pitting resistance equivalent (PRE) equations and many experimental results. However, Cr can improve the corrosion resistance, but facilitate the formation of sigma phase. Also. Mo has the same effect in stainless steels. If Cr and Mo are added at high amount to increase the corrosion resistance of stainless steel, corrosion resistance in annealed alloys can be improved, but in case of welding or aging heat treatment. its resistance will be drastically decreased. In this work, increasing Cr and N contents but decreasing Mo than the commercial alloys made the experimental alloys. Typical alloys are 25Cr-4.5Mo-0.43N alloy, 27Cr-4.7Mo-0.4N alloy, 27Cr-5.3Mo-0.25N alloy, 32Cr-2.6Mo-0.36N alloy. After annealing and aging heat treatment, microstructures, anodic polarization test, and pitting corrosion test were performed. Annealed alloys showed $100^{\circ}C$ of CPT and aged alloys showed the different tendency depending upon Cr and Mo contents(SFI)

• Tribology and Lubricants
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• v.16 no.4
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• pp.241-246
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• 2000

The effect of post-irradiation shelf-aging time on the wear of UHMWPE was investigated, and wear results were correlated with the time-dependent microstructural changes of polyethylene after gamma irradiation sterilization. The levels of oxidation and crosslinking in the shelf-aged acetabular liners were examined by FTIR and hot xylene extraction, respectively, and uni-directional repeat pass sliding wear tests were conducted by using a pin-on-disc wear tester. Gamma irradiation sterilization in the air environment caused an increase of oxidation, crosslinking, and wear resistance. With aging, however, oxidation progressed and decreased the level of crosslinking. This resulted in a decrease of wear resistance of UHMWPE that was accompanied with white bands and brittle cracking.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.11a
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• pp.296-302
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• 1999

The effect of post-irradiation shelf-aging time on the wear of orthopaedic grade UHMWPE was investigated, and wear results were correlated with the time-dependent microstructural changes of polyethylene after gamma irradiation sterilization. The levels of oxidation and crosslinking in the shelf-aged acetabular liners were examined by FTIR and hot xylene extraction, respectively, and uni-directional repeat pass sliding wear tests were conducted by using a pin-on-disc wear tester. Gamma irradiation sterilization in the air environment caused an increase of oxidation, crosslinking, and wear resistance. With aging, however, oxidation progressed and decreased the level of crosslinking. This resulted in a decrease of wear resistance of UHMWPE that was accompanied with the existence of white bands and brittle cracking.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.221-224
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• 1997

In this study we investigated the acting characteristics of Polymers for electrical insulation by UV radiation and salt water spray treatment. We used the Polymers such as EPDM, SR. PTFE. EVA. We measured contact angle and surface resistance to know the aging characteristic of Polymer surface. And we use SEM to observe the change of the surface shape. Dry flashover voltage test impulse voltage test were carried for the polymer insulator(EVA) . Through this experiment and the analysis we could know the polymers have a good resistance to weathering conditions like as salt spray UV irradiation and mix of them. And we can compare the aging characteristics between Polymers. As a result, we could know that the surface characteristics of PTFE is better than the other. And the degree, electrical characteristics is affected by change of surface shape is not big.

• Journal of Korea Society of Digital Industry and Information Management
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• v.6 no.1
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• pp.69-81
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• 2010

Physical manifestations of aging due to the lack of exercise include the slowing down of motor learning, cardiopulmonary degradation, and the increasing difficulty to adapt to the environment. Aging is manifested with the lack of aerobic exercise work, decrease in muscular endurance, decline in skeletal and muscular strength, flexibility and agility, and the decrease in reaction speed and balance. Added to those are aging-related physiological changes, including the reduction of muscle bulk, increased body fat, decrease in total body water and basic metabolic rate as activities are reduced, and a decrease in cell and Lean Body Mass (LBM). These changes are known to cause problems. Interest and participation in appropriate physical activities among the elderly is needed to help them increase stamina, avoid diseases, maintain a clear intellect, and basically enable the elderly to live their daily lives as easy as possible. Therefore, physical activities are necessary for the elderly to enhance health-related factors. Special exercises should be performed for the enhancement of muscle function, muscle endurance, flexibility, agility, and balance. An accurate measurement of cardio-respiratory endurance and stamina through basic physical and cognitive characteristics of older adults is also required to ensure safety. Also, the development of a more scientific resistance exercise prescription system for the elderly is desperately needed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.406-409
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• 2002

The primary insulation system used in an oil-filled transformer is Kraft paper, wood, porcelain and, of course, oil. Modern transformers use paper that is chemically treated to improve its tensile strength properties and resistance to aging caused by immersion in oil. These insulation papers are mainly aged to thermal stress. Over the course of the insulation paper and oil's life it is exposed to high temperatures, oxygen and water. Its interaction with the steel of the tank and core plus the copper and aluminium of the windings will eventually cause the chemical properties of the oil to decay. High temperature have an effect on mechanical strength of cellulous paper using the layer insulation. We made two aging cell in which thermal aging tests of insulation papers and mineral oil are conducted. It is measured dielectric strength, number of acid, moisture, etc. of insulation paper and oil aged in the aging cells.

• Journal of the Korean institute of surface engineering
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• v.50 no.5
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• pp.380-385
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• 2017

Mechanical characteristics of the STS 304 which is heat resistance steel were investigated after artificial aging at $650^{\circ}C$ with 1,000 hours. Tensile test specimens and small test pieces were done artificial aging up to 1,000 hours in the high temperature atmospheric environment. The results present that as the aging time increased, tensile properties were deteriorated. In the case of failure mechanism, the configuration of the fractography presented drastic change from ductile to brittle with aging time. $M_{23}C_6$ carbide leading to the change of the mechanical properties and fracture mode of the aged STS 304 steel continuously precipitated along the grain boundaries of austenite microstructure.