• Journal of Sensor Science and Technology
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• v.33 no.5
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• pp.359-365
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• 2024

Chemiresistive semiconductor metal oxide (SMO) gas sensors detect gases based on resistance changes caused by gas adsorption/desorption on SMOs. These sensors have witnessed significant advancements with the development of microelectromechanical systems (MEMS) and nanotechnology. MEMS technology has facilitated mass production, miniaturization, and uniformity across sensors. Whereas, nanotechnology has contributed to the development of high-sensitivity gas sensing materials with large surface areas, catalytic coatings, and hybrid SMO junctions. However, SMOs require activation via external energy to overcome their bandgap energy and generate hot electron carriers, which are essential for high sensitivity and fast response/recovery times. Traditionally, embedded heaters have been used for this purpose; however, micro-and nano-heaters are plagued by high power consumption and low durability, which limit their use in mobile applications. Consequently, photoactivated gas sensing using light sources (e.g., lamps and LEDs) has garnered attention as an alternative approach. This study reviewed the progress from early lamp and LED-based research to recent studies on monolithic micro-LED (µLED) based gas sensors. µLED gas sensors facilitate room-temperature operation and ultra-low power consumption within the microwatt range. Consequently, they are highly suitable for integration into consumer electronics, smart farms, smart factories, and mobile gas sensors.

• Journal of Nutrition and Health
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• v.53 no.5
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• pp.464-475
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• 2020

Purpose: This study compared the effects of a high glycemic load (high GL) diet and low glycemic load (low GL) diet on the body weight, body fat, blood pressure, and blood lipid indicators. Methods: Twenty-one young adults aged between 21 and 28 years who were overweighted or obese (body mass index [BMI] between 23 and 33.5 kg/㎡) before the study and after calorie reduction diets with either low GL or high GL for 2 weeks each were examined. The study was a randomized crossover design with a 2-week washout period between the 2 types of diet. The order of the low GL and high GL diet periods was randomized. The body weight, body fat, blood pressure, levels of blood lipids, fasting glucose, insulin, homeostatic model assessment (HOMA) insulin, C-peptide, and HOMA C-peptide were measured at the baseline, as well as 2, 4, and 6 weeks after starting the experiment. Results: When subjects were on the low GL diet, they lost more weight than those eating the high GL diet (mean ± SD, -2.77 ± 1.09 vs. -1.56 ± 0.78 kg; p < 0.001); there were greater decreases in body fat mass (-1.62 ± 1.19 vs. -0.88 ± 0.91 kg; p = 0.024) and BMI (-0.95 ± 0.32 vs. -0.56 ± 1.08 kg/㎡; p < 0.001). On the other hand, there were no significant differences in changes in biochemical parameters, such as blood lipids and fasting glucose levels, and blood pressure. The body weight, body fat mass, BMI, percent body fat, blood pressure, cholesterol (total, low-density lipoprotein, and high-density lipoprotein), fasting glucose, C-peptide, HOMA-insulin resistance-C-peptide levels were decreased significantly at 6 weeks. Conclusion: The low GL diet may be more effective in losing body weight, body fat mass, and BMI than the high GL diet for 2 weeks in healthy young overweight or obese adults.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.278-290
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• 2016

The purpose of this study is to investigate the association of total cholesterol levels (TC) and the incidence of hypercholesterolemia in response to changes in BMI. The subjects included a total of 28,249 industrial workers (25,548 male and 2,701 female) aged 30-69 years old who had received regular medical check-ups at least once per year from 2002 to 2012 (over 11 years). Data from this period were categorized into a first term (2002-2005), middle term (2006-2009), and last term (2010-2012). Then, the average TC was stratified by BMI, which was obtained from the initial examination results of each individual. In addition, average changes in TC were analyzed by stratifying with changes in BMI over 10 years (starting in 2002). The annual occurrence rates of hypercholesterolemia stratified by BMI were further assessed in patients with normal ranges of TC. In all three terms, the average TC was significantly elevated in the obese group ($25.0kg/m^2$) compared to the low weight group ($18.5kg/m^2$) and the normal weight group ($18.5-25.0kg/m^2$). Similarly, the group with higher BMI presented elevated rates of hypercholesterolemia compared to the groups with low BMI. In addition, increased BMI over the 10 year period significantly influenced TC. Consequently, it is suggested that evaluation and intervention for obesity control may be needed in order to manage the risk of high serum lipid levels.

• Reproductive and Developmental Biology
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• v.34 no.3
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• pp.263-270
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• 2010

Luteal cells produce progesterone that supports pregnancy. Steroidogenesis requires coordination of the anabolic and catabolic pathways of lipid metabolism. In the present study, the corpus luteum (CL) in early pregnancy established from luteal phase and pregnant phase was analyzed. The first study determined progesterone changes in the bovine CL at day 19 (early maternal recognition period) and day 90 in mid-pregnancy and compared them to the CL from day 12 of the estrous cycle. CL alternation was tested using two-dimensional polyacrylamide gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF). Comparing CL from luteal phase to those from pregnant phase counterparts, significant changes in expression level were found in 23 proteins. Of these proteins 17 were not expressed in pregnant phase CL but expressed in luteal phase counterpart, whereas, the expression of the other 6 proteins was limited only in pregnant phase CL. Among these proteins, vimentin is considered to be involved in regulation of post-implantation development. In particular, vimentin may be used as marker for CL development during pregnancy because the expression level changed considerably in pregnant phase CL tissue compared with its luteal phase counterpart. Data from 2-DE suggest that protein expression was disorientated in mid pregnancy from luteal phase, but these changes was regulated with progression of pregnancy. These findings demonstrate CL development during mid-pregnancy from luteal phase and suggest that alternations of specific CL protein expression may be involved in maintenance of pregnancy.

• Korean Journal of Health Education and Promotion
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• v.6 no.1
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• pp.22-33
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• 1989

Rapid socio-cultural and economic changes in the country has brought with it changes in the society's value system. For a traditional society that is increasingly being exposed to modernization but where sex norms are still very restrictive, the adolescent sexual mores takes on added significance. Adolescents are caught between two opposing forces, the changing environment that allows for freer and liberal mores and the traditional society that cannot keep pace with the changing environment and therefore demands resistance to changes. This paper focuses on problems of adolescent sexuality in this country and considers the countermeasures for the existing problems. Amongst the problems are: (a) increasingly younger age of the adolescents who start sexual intercourse (b) non-use of contraception, (c) unwanted pregnancies, (d) increase in the number of induced abortion and (e) increase in the number of unwanted children and unmarried mothers. The Korean adolescent's sexual behavior seems to follow that of the developed countries. In other words, many western modes of life and sexual values seem to bave been copied in Korea and yet Korean adolescents lack in their knowledge of sex related matters such as reproductive physiology and contraception. Among middle and high school students, female students are reported to have less knowledge on sex than male students according to a 1988 survey by KIPH. Even among the unmarried famale factory workers, only 42.5 percent replied they know of the condom, and 25.1 percent and 23.1 percent said they had knowledge of spermicide and menstrual regulation respectively. However, 14.9 percent and 13.9 percent reported that they had a knowledge of the loop and female sterilization respectively according to the 1984 study by KIPH. Among the middle school students 0.8 percent said they had experience in sexual intercourse, while 7.3 percent of the high school students reported having had sexual intercourse. The sexual intercourse experience rate among the unmarried female factory workers is 37.8 percent. Among those female factory workers with sexual experience, 46.7 percent had more than one sex partners. Only 39.1 percent of male students and 18.9 percent of female students among those with sexual intercourse experience have used contraceptives. mostly condoms and oral pills 45.1 percent of female factory workers with sexual intercourse experience used contraceptives such as pills, condoms and rhythm methods. The pregnancy experience rate among the female factory workers who had experience in sexual intercourse is 29.5 percent, which is 11.1 percent among the total respondents. Out of the 102 pregnant female workers, 98 workers(96.1 percent) terminated their pregnancy by induced abortion and 2 workders(2 percent) in natural abortion, while 1 worker(1 percent) was in pregnancy and another 1 worker had normal birth that was subsequently sent to orphanage. In order to cope with the problem of adolescent sexuality, a drastic and strong policy measures should be taken by the government. The most effective countermeasure to the adolescent sexual problems appears to the education. The sex and population education in the school is very much in need. In addition, sex education program through mass media and at the job sit-should be promoted for a healthy development of adolescents' sexual behavior. Also, the existing national family planning program, which has focused on the married couples, should be extended to the unmarried people in its scope and contents of the program.

• Journal of Life Science
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• v.21 no.8
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• pp.1127-1133
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• 2011

Exercise has been shown to positively influence quality of life for elderly men with a wide variety of medical illnesses. Tai chi exercise, a slow and graceful form of exercise and meditation, has especially been offered as the ideal exercise for elderly men with diverse conditions, such as people suffering from chronic heart failure or breast cancer survivors. In one recent study, Tai Chi was found to improve exercise capacity, sleep stability, and quality of life in heart failure patients including elderly men. The purpose of the study was to examine the effects of 16 weeks of Tai Chi exercise (3 times/week, 60 min/trial, 40-50% HRR) on physical and physiological changes. Sixty four healthy volunteers without any particular disease between the ages of 65 and 79 years participated in the study. The results were as follows; Significant changes of cardiac endurance, strength, muscle endurance, flexibility and balance were observed following 16 weeks of Tai Chi exercise (p<0.05). In addition, significant changes of diastolic blood pressure, body fat and fat-free mass were observed following 16 weeks of Tai Chi exercise (p<0.05). These findings suggest that a brief period of Tai Chi exercise is beneficial, particularly to elderly men. It is especially beneficial for body composition, and physical fitness factors such as cardiopulmonary endurance, muscle endurance, flexibility, and balance. Further study is needed in this area for specific disease patients.

• The Korean Journal of Food And Nutrition
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• v.16 no.3
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• pp.192-196
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• 2003

The purpose of this study was to investigate the changes of body composition, serum lipids and several parameters of body fatness (percent body fat, waist-hip ratio) in abdominal women by exercise. For this study, 8-weeks intensive exercise(5km jogging/day, 50min/day) was continued by subjects and they limited only fat rich foods and controlled daily energy intake to 1,800kcal～2,100kcal per day. The subjects were 52 women and the distribution of ages was 36～54 years. The data were analyzed using SPSS/PC package program and the results were estimated by paired t-test, Pearson correlation. The results are summarized as follows : 1) After exercise-training for 8 weeks, percent body fat, body mass index, body weight, total cholesterol was decreased (p<0.05). 2) LDL cholesterol and triglyceride was decreased significantly(p=0.000). The changes in deep abdominal adipose tissue were related to changes in triglycerides. 3) After exercise training, the waist-hip ratio was significantly correlated to body weight and serum lipids. 4) According to the data of this study, Ⅰ recommended that obese women, especially, abdominal obese patients should exercise regularly and we should prolong many studies for obesity.

• Korean Journal of Environmental Biology
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• v.31 no.3
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• pp.204-212
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• 2013

This study analyzed the occurrence of tunic softness, survival rate, metabolic rate and histopathologic changes arising from the effect of hypoxic environment in order to find the causes of occurrences of tunic softness, which manifests as the key phenomenon of mass mortality of Halocynthia roretzi. Regarding the survival of H. roretzi with reduction in dissolved oxygen, all the entities died on the 4th day of exposure to the dissolved oxygen concentration of $2mg\;L^{-1}$ while 50% mortality was observed on the 5th day of exposure to the dissolved oxygen concentration of $3mg\;L^{-1}$. Therefore the 5 days-$LC_{50}$ was found to be $3.55mg\;L^{-1}$ (1.86~$4.96mg\;L^{-1}$). However, occurrence of tunic softness was not observed during the period of exposure to low oxygen concentration. The oxygen consumption rate significantly decreases at the dissolved oxygen concentration of less than $5mg\;L^{-1}$ in comparison to the control group. Therefore, it is presumed that H. roretzi controls the respiration rate for prescribed period of time when exposed to hypoxic environment. Regarding the histopathologic changes in the gill, digestive gland and cyst of H. roretzi due to hypoxic environment, necrosis of epithelial layer, in filtration of blood cells, and condensation of nucleus that compose each of the organs were observed. Regarding morphological changes, the decrease in volume with shrinking of the tunic, discoloration of the internal organs and necrosis of gill and hepatopancreas were observed.

• The Korean Journal of Food And Nutrition
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• v.29 no.5
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• pp.785-794
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• 2016

This research was conducted to evaluate quality changes in traditional Doenjang and manufactured Doenjang during a storage period of 8 weeks. Low-salt Doenjang and commercial Doenjang were purchased from different manufacturers and proximate analysis as well as changes in isoflavone, polyphenol, flavonoid contents of the samples were investigated using a mass spectrophotometer. The salinity of traditional Doenjang, low salt Doenjang, and commercial Doenjang were $13.2{\pm}1.15$, $7.17{\pm}2.74$, $10.67{\pm}0.35%$, respectively and the salt concentrations of the soybean pastes did not change during storage. After 8 weeks at $35^{\circ}C$, chromatic values of all the paste samples decreased somewhat, with traditional Doenjang exhibiting fewer changes as compared to manufactured Doenjang. Amino acid nitrogen, acidity, microbial population all tended to increase with time, although some samples showed fluctuations during the test period. Moreover, the total isoflavone contents of traditional Doenjang increased with storage time while that of manufactured Doenjang tended to decrease. The isoflavone aglycone was shown to be the highest in traditional Doenjang, while isoflavone glycoside was abundant in manufactured Doenjang. Total flavonoid contents showed similar trends regardless of samples; initial contents of total flavonoid was 0.6 mg/g which increased to more than twice to 1.4 mg/g at the end of storage period. Composition profile of Doenjang extracts was analyzed using UPLC-Q-ToF.

• Applied Biological Chemistry
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• v.34 no.2
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• pp.134-141
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• 1991

In order to investigate the changes and characteristics of biochemical metabolic substances of soybean tissue culture during the cultural period, immature cotyledons were detached form the plant on 15th days after flowering and cultured in vitro for 3 weeks. The cultures were classified into embryogenic(EC) and non-embryogenic callus(NEC). A part of the EC lines were subcultured for another 3 weeks and classified into root forming(RFC), and shoot forming cultures(SFC). Another part of the EC lines were used for isolation of protoplasts, which were subsequently cultured in vitro for 4 weeks. The cultures were classified into embryogenic(PEC) and non-embryogenic callus(PNEC) derived from the protoplasts. The cultures of EC and PEC lines showed higher phenylalanine content and lower methionine content than those of NEC and PNEC. At organ differentiation stage, both cultures showed the content of aspartic acid decreased, while the other amino acids increased as a whole. The protein pattern analysis of the cultures revealed that EC and NEC lines contained distinctive polypeptides, with mass of ca. 18KD for EC and ca. 22KD for NEC respectively. The EC and PEC lines also showed high activity of peroxidase isozyme A(piA), while the RFC and SFC lines showed that of peroxidase isozyme B(piB).