• Journal of Life Science
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• v.30 no.2
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• pp.202-210
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• 2020

As the elderly population increases, it is becoming important to prevent and treat muscle loss caused by aging or disease. Steroidal androgen in the protein assimilation steroid (AAS) system is mainly used to induce muscle improvement, but it is well known that long-term or excessive doses of AAS result in various side effects, although they are prescribed for various muscle and weight loss treatments. Research is therefore underway to explore natural substances that promote muscle renewal with relatively few side effects. However, despite many studies on the improvement of skeletal muscle and the reduction of muscle disease using natural products, there is still a lack of significant clinical results and mechanism studies. The promotion of muscle regeneration through treatment with natural substances typically involves three mechanisms: positive control of the muscle modulating factor (MRF), activation of the protein synthesis mechanism, and inhibition of the protein breakdown mechanism. A study of plant extracts that are known to have muscle neoplasmic stimulation effects, such as black ginseng, plum, and nutmeg, as well as single substances derived from natural products, such as creatine, catechin, and several fatty acids, is therefore described. We also summarize the mechanisms that have been identified so far through which each of these extracts or single materials facilitates muscle regeneration and the signaling pathways that they mediate.

• Journal of Life Science
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• v.23 no.1
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• pp.131-136
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• 2013

Sirtuin proteins have emerged as important modulators of several age-associated diseases. These include cancer and diabetes, as well as cardiovascular and neurodegenerative diseases. Among the sirtuin family members, SIRT2 mRNA is strongly expressed. To investigate the pathophysiological significance of SIRT2 as a primary regulator of angiogenesis, we focused on the biological role of SIRT2 under hypoxic conditions, examining the gene expression pattern of sirtuin family members in human umbilical vein endothelial cells (HUVECs). SIRT2 was expressed primarily in the cytoplasm, but it was dynamically trans-localized in the nuclear by hypoxia stimuli. Interestingly, both SIRT2 and the pro-angiogenic factor, VEGF, were up- regulated by hypoxia. A Matrigel assay demonstrated that the HUVECs formed a tube-like structure under hypoxia. The SIRT2 inhibitor, AK-1, significantly decreased the tube-forming activity of the HUVECs under either normoxia or hypoxia conditions. These findings suggest that SIRT2 might be a key regulator of angiogenesis.

• Journal of Life Science
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• v.27 no.9
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• pp.1078-1085
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• 2017

Free radicals have long been considered damaging to various tissues. An excessive amount of reactive oxygen species (ROS) is known to have detrimental effects on the body and to be linked to numerous pathological conditions, such as cardiovascular disease, cancer, diabetes, and skeletal muscle atrophy. On the other hand, recent findings suggest that ROS is important for maintenance and development of cellular activity. Cells respond to increased oxidative stress by adaptive changes in the expression of a variety of proteins involved in the maintenance of cellular integrity. ROS is also essential for skeletal muscle function and metabolism. It is well known that physical exercise has many health benefits. Paradoxically, physical exercise also stimulates the production of ROS, which result in oxidative stress. Based on evidence amassed in the past decade, exercise itself may be considered an antioxidant because training increases the expression of antioxidant enzymes. In this review, we discuss the processes underlying the generation of ROS and its role in exercise-induced adaptation based on recent evidence. Furthermore, we discuss the possible role of NADPH oxidase in exercise-induced activation of insulin signaling and its effect on longevity.

• Korean Journal of Remote Sensing
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• v.38 no.6_1
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• pp.1191-1205
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• 2022

Particulate matter(PM) among air pollutants with complex and widespread causes is classified according to particle size. Among them, PM_2.5 is very small in size and can cause diseases in the human respiratory tract or cardiovascular system if inhaled by humans. In order to prepare for these risks, state-centered management and preventable monitoring and forecasting are important. This study tried to predict PM_2.5 in Seoul, where high concentrations of fine dust occur frequently, using two ensemble models, random forest (RF) and extreme gradient boosting (XGB) using 15 local data assimilation and prediction system (LDAPS) weather-related factors, aerosol optical depth (AOD) and 4 chemical factors as independent variables. Performance evaluation and factor importance evaluation of the two models used for prediction were performed, and seasonal model analysis was also performed. As a result of prediction accuracy, RF showed high prediction accuracy of R² = 0.85 and XGB R² = 0.91, and it was confirmed that XGB was a more suitable model for PM_2.5 prediction than RF. As a result of the seasonal model analysis, it can be said that the prediction performance was good compared to the observed values with high concentrations in spring. In this study, PM_2.5 of Seoul was predicted using various factors, and an ensemble-based PM_2.5 prediction model showing good performance was constructed.

• Journal of Life Science
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• v.31 no.11
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• pp.1037-1045
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• 2021

The prevalence of obesity is increasing worldwide, and since obesity is associated with dietary factors and sedentary lifestyles, it is a disease that is readily developing in the modern population. Because obesity is accompanied by serious complications such as diabetes and cardiovascular disease, prevention and treatment are important. Currently, drugs such as liraglutide and phentermine are used to treat obesity by suppressing appetite and inducing gastrointestinal motility delay. However, various side effects may occur, including thyroid cancer, cardiovascular problems, and central nervous system disorders. Therefore, to explore an obesity treatment method with relatively few side effects, a method known as "fat browning" was introduced to change white adipose tissue into brown adipose tissue to increase energy consumption. Ongoing studies are attempting to find effective natural substances to safely induce browning. Many natural substances have been identified. The induction of browning by treatment with natural substances generally involves three mechanisms: positive control of browning-inducing factors, inhibition of differentiation into white adipose tissue, and the activation of mechanisms related to browning. In this study, we describe plant extracts with known browning-inducing effects, such as strawberry, black raspberry, cinnamomum cassia, and Ecklonia stolonifera extracts. We also summarize the underlying mechanisms of action identified thus far, including the signaling pathway mediated by these extracts to induce browning. Furthermore, the effects of brown adipose tissue generated through browning on heart disease as an endocrine organ disruptor are discussed.

• Journal of Life Science
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• v.33 no.7
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• pp.574-585
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• 2023

Sarcopenia is a leading cause of increased medical and nursing care costs among the elderly. In Korea, preventive measures for sarcopenia are mostly targeted toward the general elderly population without specific diseases. However, it is also necessary to implement measures for elderly individuals living in nursing homes and hospitals, where the prevalence of sarcopenia is high. Currently, computed tomography and/or magnetic resonance imaging are considered standard diagnostic tools. However, their complexity and time-consuming nature make them unsuitable for clinical use. The exact pathophysiological mechanisms of sarcopenia are unclear, as they involve various molecular biological pathways, including decreased exercise, protein and nutrient intake, changes in testosterone and growth hormone, and inflammation. Sarcopenia symptoms can lead to several diseases, such as osteoporosis, fractures, dementia, diabetes, and cardiovascular disease. Vitamin B deficiency is a significant factor in sarcopenia induction, with B vitamins being directly involved in energy and protein metabolism and nerve function. Vitamin B deficiency can lead to neuromuscular and neurogenic disorders, which often overlap with sarcopenia. Suboptimal intake of B vitamins, malabsorption, and anorexia are common among the elderly. This study aims to provide information on the role of water-soluble B vitamins in preventing and controlling muscle mass loss and deterioration among the elderly with sarcopenia. In addition, we discuss the potential of myokines from the B vitamin family in modulating sarcopenia.

• Korean Journal of Social Welfare Studies
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• v.41 no.1
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• pp.251-279
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• 2010

In 2009 the Ministry of Health and Society reported a new milestone in longevity among people living with HIV and AIDS (PLWHA): An individual was reported to be living and healthy after 24 years with HIV/AIDS. Today, PLWHA who receive treatment are more likely to die as a result of cancer or cardiovascular diseases than HIV/AIDS. However, in Korea the public association between HIV/AIDS and death remains strong and PLWHA live with the feeling of being discarded. While great advances have been made in the treatment of HIV/AIDS, understanding of life with HIV/AIDS is just beginning. This study describes the life experiences of PLWHA after being diagnosed with HIV/AIDS. Phenomenological methods were used to analyze the transcripts of semi-structured interviews with six PLWHA. Time is a constant factor in the life experiences of PLWHA. After being diagnosed, participants were shocked, feeling as though the world was caving in and they were living with a time bomb. Compulsory disclosure left PLWHA with a feeling of disconnection from the world. Participants were fired from their jobs, resulting in poverty, isolation and a sense that they were simply waiting to die. However, health professionals informed participants that HIV/AIDS is a manageable illness. With time, PLWHA came to understand HIV/AIDS differently. In accepting their HIV infection, PLWHA created a new sense of meaning in their lives. To be honest to their loved ones and true to their own identity, PLWHA worked to "come out." The experience of coming out helped them to accept themselves as they were and understand their own strength. The most important influence on their treatment, and living with HIV/AIDS generally, was obtaining correct information about HIV/AIDS from health professionals. After accepting that they were living with HIV/AIDS, participants were able to look beyond themselves to support those around them, including family members, friends, and others who encouraged them to recognize and feel confident in their own identity.

• Journal of Dairy Science and Biotechnology
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• v.33 no.1
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• pp.35-46
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• 2015

Recently, much attention has been paid to the development of a value-added food category containing probiotics so as to improve human health and prevent diseases. Among various foods, the health benefits of milk and dairy products are known to humanity, and could be attributed to the bioactive components present in milk. In fermented milk products, the health benefits could be due to suitable modulation activities produced by the action of probiotic bacteria. Besides the modification of various milk components, probiotics might also act directly as preventive and therapeutic agents against some severe diseases. Probiotics promote health via their positive effects on the immune response, stimulation of natural immunity, and modulation of the production of antimicrobial peptides, cytokines, and so on. Whey proteins, a byproduct of cheese production could also have anticarcinogenic, immunostimulatory, antimicrobial, and health-promoting activities such as improving insulin sensitivity and reducing fat deposition. Therefore, milk and dairy products containing probiotics could provide various opportunities in the field of functional foods. Additionally, these functional foods may be important in the human diet and may help improve human health and prevent diseases.

• The Journal of the Korea Contents Association
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• v.18 no.4
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• pp.653-663
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• 2018

This study is a descriptive survey to examine the dementia related attitudes and dementia preventive behaviors in middle aged and to determine the relationships between the both sides. In this study, between October 1st and 9th, 2017, data were collected from the middle aged people in their 40s~60s in Korea through online questionnaires. Finally, 220 questionnaires were analyzed by t-test One way ANOVA, Pearson's correlation coefficient, and etc. The results of the study are as follows. First, 52.7% of the subjects were interested in prevention of dementia, but only 5.9% of them had experience of receiving education related to dementia. Second, fear of dementia was higher than cancer, cerebrovascular disease, and cardiovascular disease, but confidence in coping with the disease, expectation of the possibility of maintaining the daily life, expectation of the help of the family and the surrounding people, expectation of the national medical and economic support were significantly lower. Third, as the dementia preventive behaviors were implemented, the confidence in overcoming the disease, the expectation of the possibility of maintaining the daily life, the expectation of the help of the family and the surrounding people, the expectation of the medical and economic support of the country increased and the burden of the treatment cost was lowered. As a result, it is thought that this personal and social effort will improve the quality of life of the people by reducing physical, psychological, social and economic problems caused by dementia.

• Journal of Nutrition and Health
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• v.55 no.3
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• pp.330-347
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• 2022

Folate, a water-soluble vitamin, acts as a coenzyme for one-carbon metabolism in nucleic acid synthesis and amino acid metabolism. Adequate folate nutritional status during the periconceptional period is known to prevent neural tube defects. In addition, insufficient folate intake is associated with various conditions, such as anemia, hyperhomocysteinemia, cardiovascular disease, cancer, cognitive impairment, and depression. This review discusses the rationale for the revision of the 2020 Korean dietary reference intakes for folate, and suggestions for future revisions. Based on the changes in the standard body weight in 2020, the adequate intake (AI) for infants (5-11 months) and the estimated average requirements (EARs) for 15-18 years of age were revised, but there were no changes in the recommended nutrient intakes (RNIs) and tolerable upper intake levels (ULs) for all age groups. Mean folate intake did not reach RNI in most age groups and was particularly low in women aged 15-29 years, according to the results of the 2016-2018 Korea National Health and Nutrition Examination Survey (KNHANES). The percentages of folate intake to RNI were lower than 60% in pregnant and lactating women, but serum folate concentrations were higher than those in other age groups, presumably due to the use of supplements. Therefore, total folate intake, from both food and supplements, should be evaluated. In addition, the database of folate in raw, cooked, and fortified foods should be further expanded to accurately assess the folate intake of Koreans. Determination of the concentrations of erythrocyte folate and plasma homocysteine as well as serum folate is recommended, and quality control of the analysis is critical.