• 제목/요약/키워드: Science and Technology (S&T)

검색결과 3,205건 처리시간 0.038초

Age Structure and Biomass of the Icefish Pseudochaenichthys georgianus Norman (Channichthyidae) Between 1976 and 2009: a Possible Link to Climate Change

  • Traczyk, Ryszard;Meyer-Rochow, Victor Benno
    • Ocean and Polar Research
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    • 제41권4호
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    • pp.233-250
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    • 2019
  • A re-assessment of the age structure of the population of the Antarctic icefish Pseudochaenichthys georgianus based on body length data covering the years 1976-2009 and including larvae and postlarvae collected in 1989 and 1990 allowed us to define age groups 0, I, and II as containing fish with respective body lengths of 6-9 cm, 15-27 cm and 27-39 cm. Age at maturity (first spawning) was found to occur in age group III at body lengths that have been falling from 50.1 cm in 1979 to 45.4 cm in 1992. Considering postlarvae together with adult fish, the v. Bertalanffy growth curve parameters were determined as L = 60.62 cm, k = 0.4, t0 = 0.25. Although the reasons for a maturity at shorter body lengths is not fully understood a host of environmental factors like increasing water temperatures and possibly changes in currents, interspecific competition, food availability, etc. are likely to be involved. Global warming (and not primarily overfishing) is likely to have been responsible for the disappearance of larger fish in the surface waters of South Georgia since 1977, for virtually all commercial fishing stopped in the early 1990s. On the other hand, the appearance of numerous younger spawning individuals suggests that larvae do survive in the colder deeper water below 200 m. The biomass of Ps. georgianus oscillates with a 4-year periodicity in contrast to that of the coexisting icefish Chaenocephalus aceratus: the former with a lower biomass in warm years and a higher one in cold years. The biomass of the third species of icefish in the region, i.e. Champsocephalus gunnari, also oscillates, but with a longer periodicity than that involved in the biology of the other two and its biomass increases in contrast to the other two species. The result is that the biomass all three species considered together is rather stable.

Influencing factors on oral health related self-efficacy and social support in high school students (고등학생의 구강건강관련 자기 효능감과 사회적 지지에 영향을 미치는 요인)

  • Kim, Young-Im;Yu, Sang-Hui
    • Journal of Korean society of Dental Hygiene
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    • 제15권1호
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    • pp.129-135
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    • 2015
  • Objectives: The purpose of this study is to investigate the influencing factors on oral health related self-efficacy and social support in high school students. Methods: The subjects were 750 high school students in Jeonbuk by convenience sampling. A self-reported questionnaire was completed from April 3 to June 4, 2013. Except incomplete answers, 589 data were analyzed using SPSS 18.0 program for t-test, ANOVA, post hoc Scheffe test, and multiple regression analysis. The questionnaire consisted 6 questions of general characteristics of the subjects, 8 questions of oral health related self-efficacy, and 8 questions of oral health related social support. The instrument for self-efficacy was developed by Sherer and Maddux and measured by Likert 4 scale. Interpersonal Support Evaluation List(ISEL) was developed by Cohen and Hoberman and revised by Suh as oral health related social support in high school students, and measured by Liker 4 scale. Cronbach's alpha in self-efficacy was 0.768 and that in social support was 0.772. Results: The good oral health behavior in the high school students was closely related ro self-efficacy and social support. Higher self-efficacy and social support could make the students practice good oral behavior. Conclusions: Higher self-efficacy and social support can influence on the good oral health behavior in high school students. So it is very important to provide the continuous oral health education that can enhance self-efficacy and health promotion.

Smart Tourism: A Study of Mobile Application Use by Tourists Visiting South Korea

  • Brennan, Bradley S.;Koo, Chulmo;Bae, Kyung Mi
    • Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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    • 제8권10호
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    • pp.1-9
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    • 2018
  • The purpose of this exploratory study is to identify the mobile phone applications (apps) used by foreign tourists visiting South Korea through a pilot study using focus groups and individual interviews. Concentrating on tourist mobile app use in a smart tourism environment and categorized through a taxonomy of mobile applications lays the framework and determines the factors boosting tourism smartphone app trends by foreign tourists visiting South Korea. Researchers collected data through ethnographic methods and analyzed it through qualitative research to uncover major themes within the smart tourism app use phenomenon. The researchers coded, counted, analyzed, and then divided the findings gleaned from a pilot study and interviews into a taxonomy of seven logical smartphone app categories. The labeling and coding of all the data accounting for similarities and differences can be recognized and are logically discussed in the implications of the apps used by tourists to assist tourist destinations. More specifically these findings will assist smart tourism destinations by better understanding foreign tourist smartphone app use behavior. Tourists visiting South Korea interviewed in this study exhibited significant mastery of Internet of Things (IoT) technologies, craved free WiFi access, and utilized smartphone apps for all facets of their travel. Findings show major concentrations of app use in bookings of accommodations, tourist attractions, online shopping, navigation, wayfinding, augmented reality, information searching, language translation, gaming, and online dating while traveling in South Korea.

Effects of Yucca Extracts and Protein Levels on Growth Performance, Nutrient Utilization and Carcass Characteristics in Finishing Pigs

  • Min, T.S.;Kim, J.D.;Lee, J.H.;Hyun, Y.;Sohn, K.S.;Han, In K.
    • Asian-Australasian Journal of Animal Sciences
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    • 제14권4호
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    • pp.525-534
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    • 2001
  • A total of 120 pigs were used to investigate the effects of yucca extracts on the growth performance, nutrient digestibility, nutrient excretion and carcass characteristics of finishing pigs fed different levels of dietary protein. Pigs were allotted into $2{\times}3$ factorial design by the supplementation of yucca extracts (YE, 0 and 120 mg/kg) and 3 levels of dietary protein (14, 16, 18% for early finisher and 12, 14, 16% for late finisher for low, medium and high protein diet, respectively). During the early finishing period (51~76 kg BW), no significant difference was found in growth performance regardless of the YE supplementation or dietary protein levels. Growth performance of late finishing pigs (76~101 kg BW) was also not significantly different among treatments. However, ADG of pigs fed YE diet was significantly improved (p<0.05) regardless of the dietary protein levels. For the overall period (51~101 kg BW), although adding YE to the diet and elevating the protein level showed better ADG, there were no significant differences on growth performance among treatments. Early finishers showed significantly higher crude protein, crude ash and crude fat digestibilities when they were fed diets supplemented with YE. Digestibilities of amino acids were not affected by YE. Late finishers did not show any significant differences in proximate nutrient digestibilities regardless of YE supplementation or dietary protein levels. YE tended to slightly improve the CP digestibility, however no significant difference was found with increased dietary protein levels. There was no significant difference in amino acid digestibilities with YE supplementation or dietary CP levels during the late finishing period. Dry matter (DM) and nitrogen (N) excretion in feces did not show any significant difference among treatments. Early finishing pigs also did not respond to the inclusion of YE or dietary protein levels (p<0.05). Fecal N excretion of early finishing pigs seemed to be lowered in pigs fed YE. Pigs fed medium dietary protein diet tended to excrete a higher amount of N during the early finishing period, but not statistically different. A slight increase in fecal N excretion was found with the increased level of dietary protein during the late finishing period. For ammonia nitrogen excretion, although there was no significance, the NH3-N content tended to be increased by the increased dietary protein levels and with YE supplementation. The NH3-N content in manure increased by 24.5% with YE supplementation. There were no significant differences in carcass weight, backfat thickness, carcass grade and loin eye area among treatments. However, pigs fed non-YE with low protein diet showed a significantly (p<0.05) low carcass ratio among treatments and there was significant (p<0.05) difference between the YE-added treatment and non YE treatment in carcass ratio. As for the feed cost, the cost of feeding high level protein was higher than that of medium level protein by 5% and low level protein by 9% (p<0.05). Therefore, based on this study, it could be concluded that environmentally friendly agents might play a role to some extent in finishing pigs from the aspect of pollution control, and that more than 14 and 12% of dietary protein for early finishing and late finishing pigs respectively do not necessarily guarantee high growth performance.

Activation of RAW 264.7 Macrophage by Digested Bacterial Cell of Pig-derived Lactobacillus Strains (돼지에서 분리된 Lactobacillus Strains의 균체분해산물에 의한 RAW 264.7 Macrophage 활성화)

  • Kim, D.W.;Cho, S.B.;Jeong, H.Y.;Moon, H.G.;Lee, H.J.;HwangBo, J.;Chung, W.T.;Choi, C.W.;Chung, I.B.
    • Journal of Animal Science and Technology
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    • 제47권6호
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    • pp.947-954
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    • 2005
  • This study was conducted to investigate the effects of hydrolyzed Lactobacillus supplementation with digestive enzymes treatment on the macrophage activation, the induction of nitric oxide(NO), interleukin (IL)-6 and tumor necrosis factor(TNF)-$\alpha$. The RAW 264.7 murine macrophage was exposed to porcine Lactobacillus strains which were digested with both pepsin and pancreatin. The production of NO, TNF-$\alpha$ and IL-6 in the macrophage were strain and dose-dependent, respectively. The induction of NO and cytokines were higher in both 3149 and 3146 strains compared with other Lactobacillus strains. Overall, the level of NO was observed at the lower range between 10 and 150 μg hydrolysates per ml, whereas IL-6 and TNF-$\alpha$ were observed at relatively higher concentration between 50 and 300 μg hydrolysates per ml. Lactobacillus strains which produced a high level of NO also showed a high induction of TNF-$\alpha$ and IL-6. Therefore, the present results suggest that hydrolysates of Lactobacillus strains are related to induction of several macrophage mediators, and then it could be beneficially used to modulate gastrointestinal immune function of the host. Also, the methodogly employed in this study might be useful to investigate the effects of lactic acid bacteria on gastrointestinal immunity.

Health Problems of Female workers in Small Workplace (소규모 사업장 여성근로자의 건강문제)

  • Kim, Young-Im;Yun, Soon-Nyung;Choi, Jeong-Myung;Kim, Chun-Mi;Jung, Hye-Sun
    • Research in Community and Public Health Nursing
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    • 제11권1호
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    • pp.117-126
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    • 2000
  • For basic data to develop health management program of female workers. this study was intended to characterize factors affecting health problems of women at workplace which has less than 50 workers by Cornell Medical Index(CMI). 195 items of CMI questionnaire were simplified to 57 items which were composed of 35 items concerning physical health problems and 22 items concerning mental health problems. The data was collected during 6 months from July 10 to December 30 and analyzed with frequency, percentage, t-test and ANOVA. The 107 female workers included in this study was characterized to be mainly twenties(64.5%), single(69.2%) and working at production position(89.7%). The most frequent physical problem was fatigability and the next, neurological system and cardiovascular system. Main mental complaints were inadquacy. anger and tension. When the health problems were reviewed according to its general characteristics, anger in young age, adaptiveness in single and respiratory complaints in self-recognized unhealthy group were prevalent. According to life styles. the prevalent complaints were musculoskeletal one in alcoholic group and cardiovascular one in group who are sleeping just for four to five hours. The appropriateness of each items of CMI should be evaluated to reveal the reasons why meaningful results could not come from many items of this questionnaire. The repeated study should be carried out to figure out the health problems and its related factors of female workers at small scale workplace. Also, exercise program and abstinence from drinking and smoking should be carried out for female worker's health.

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Comparison of Antifungal Activites of Monoterpenes and Sesquiterpenes in Essential Oil from Chamaecyparis obtusa against Dermatophytes (피부사상균에 대한 편백정유의 Mono- 및 Sesquiterpene 항진균 활성 비교)

  • Gwak, Ki-Seob;Park, Mi-Jin;Jeung, Eui-Bae;Chang, Je-Won;Choi, In-Gyu
    • Journal of the Korean Wood Science and Technology
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    • 제34권3호
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    • pp.46-55
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    • 2006
  • This study was to compare the antifungal activitiy of monoterpenes with that of sesquiterpenes, which were major constituents of antifungal active essential oil of Chamaecyparis obtusa, to investigate which constituents had more effective against dermatophytes, and to evaluate the synergistic effect of combination of the antifungal active constituents. The antifungal activities of seven fractions (A, B, C, D, E, F, and G) from C obtusa essential oil by column chromatography were tested against Trichophyton mentagrophytes. Fraction D, E, F, and G were more active than fraction A, B, and C, and their major compounds were mono- and sesquiterpenes analyzed by GC/MS. Borneol, linalool, and ${\alpha}$-terpineol were selected as monoterpenes, and ${\alpha}$-cedrol, nerolidol, and ${\beta}$-eudesmol as sesquiterpenes, respectively. The antifungal activities of the constituents were respectively examined against Trichophyton mentagrophytes (KCTC6077), Microsporum canis (KCTC6591), and Microsporum gypseum. The constituents of sesquiterpenes were more active than those of monoterpenes. By comparing single and combined sesquiterpenes with fraction F containing the higher ratio of sesquiterpenes, combined sesquiterpenes were the most active. This result indicated that there was the synergistic antifungal effect against dermatophytes when sesquiterpenes were combined together.

Structure of Z-1-Ethyl-2-Nitro-1-Butenyl-(4'-Methyl)-Phenyl Sulfone (Z-1-에칠-2-니트로-1-부텐일-(4'-메칠)-페닐 술폰의 구조)

  • Choong Tai Ahn;Gene B. Carpenter\;Kyong Bae Park
    • Journal of the Korean Chemical Society
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    • 제37권3호
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    • pp.351-354
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    • 1993
  • Z-1-Ethyl-2-nitro-l-butenyl-(4'-methyl)-phenyl sulfone, C$_{13}$H$_{17}$NO$_4$S, Mr = 293.4, monoclinic space group P2$_1$/c, a = 12.194(7), b = 7.290(4), c = 16.532(14)${\AA}$, ${\beta}$ = 103.4(2)$^{\circ}$, V = 1429.5 ${\AA}^3$, Z = 4, D$_c$ = 1.32 gcm$^{-3}$, ${\lambda}$(Mo K${\alpha}$) = 0.71069 ${\AA}$, ${\mu}$ = 2.2 cm$^{-1}$, F(000) = 600, T = 298 K, R = 0.030 for 1762 unique observed reflections with I > 1.0${\sigma}$(I). A molecule has a cis-typed molecular structure having the form of "the substituted butene backbone, C-C(S)=C(NO$_2$)-C, connecting to a sulfur atom with the methylbenzene ring and to a nitro group. The methylbenzene ring and the substituted butene moiety are nearly planar with the maximum deviations from their own molecular planes, 0.018 ${\AA}$ for the C(1) atom of the benzene group and 0.045 ${\AA}$ for the N atom of the NO$_2$ group, respectively. The angles to the plane of the butene backbone are 88.5$^{\circ}$from the plane of the methyl-benzene and 78.6$^{\circ}$from the plane of the nitro group. Rotation of the nitro group from the butene plane seems to reduced contribution of resonance structure involving the nitro group, and resultant repulsion between the O(2) atom of SO$_2$ and the O(3) atom of NO$_2$ appears to be 2.894 ${\AA}$ longer than an expected van der Waals distance of 2.80 ${\AA}$.

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Knowledge, Awareness and Health Risk Concerns on Occupational Exposure to Radiation among Firefighters in Korea (소방공무원의 직업적 방사선노출에 대한 지식, 자각 및 건강피해 우려)

  • Lee, Hyeongyeong;Yoon, Hyeongwan;Park, Jeongim
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • 제25권4호
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    • pp.516-524
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    • 2015
  • Objectives: This study aims to investigate the current status of knowledge, awareness and health risk concerns on occupational radiation exposures among firefighters in Korea. The results will provide basic information for developing a prevention program to minimize adverse health effects relating to radiation exposure among firefighters. Methods: A questionnaire was composed of general characteristics of participants, and their knowledge, awareness, health risk concerns relating to occupational radiation exposure. It was distributed by email to all of 307 firefighters in Jeollabukdo in April 2014 and 259 of them (response rate 84.3%) were responded. Answers were analyzed for descriptive statistics including frequencies and percentages. SPSS/WIN 18.0 program was utilized for statistical analysis of t-test, ANOVA and Pearson's correlation. Results: The average score of radiation protection knowledge was $5.83{\pm}1.77$ ($average{\pm}SD$) out of 10. The score of awareness and health risk concerns on radiation exposure were 4.27, 3.94 out of 5, respectively. The results indicated that the knowledge on the characteristics of radiation was marginal among the firefighters, while the awareness and health risk concerns relating to radiation exposures were relatively higher comparing to other professions. Conclusions: Knowing the characteristics of potential risks is the first step for minimizing the adverse health effects relating to the risks. Therefore, it is necessary to provide adequate training and information on radiation and exposure protection methods for firefighters.

Regulation of toll-like receptors expression in muscle cells by exercise-induced stress

  • Park, Jeong-Woong;Kim, Kyung-Hwan;Choi, Joong-Kook;Park, Tae Sub;Song, Ki-Duk;Cho, Byung-Wook
    • Animal Bioscience
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    • 제34권10호
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    • pp.1590-1599
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    • 2021
  • Objective: This study investigates the expression patterns of toll-like receptors (TLRs) and intracellular mediators in horse muscle cells after exercise, and the relationship between TLRS expression in stressed horse muscle cells and immune cell migration toward them. Methods: The expression patterns of the TLRs (TLR2, TLR4, and TLR8) and downstream signaling pathway-related genes (myeloid differentiation primary response 88 [MYD88]; activating transcription factor 3 [ATF3]) are examined in horse tissues, and horse peripheral blood mononuclear cells (PBMCs), polymorphonuclear cells (PMNs) and muscles in response to exercise, using the quantitative reverse transcription-polymerase chain reaction (qPCR). Expressions of chemokine receptor genes, i.e., C-X-C motif chemokine receptor 2 (CXCR2) and C-C motif chemokine receptor 5 (CCR5), are studied in PBMCs and PMNs. A horse muscle cell line is developed by transfecting SV-T antigen into fetal muscle cells, followed by examination of muscle-specific genes. Horse muscle cells are treated with stressors, i.e., cortisol, hydrogen peroxide (H2O2), and heat, to mimic stress conditions in vitro, and the expression of TLR4 and TLR8 are examined in stressed muscle cells, in addition to migration activity of PBMCs toward stressed muscle cells. Results: The qPCR revealed that TLR4 message was expressed in cerebrum, cerebellum, thymus, lung, liver, kidney, and muscle, whereas TLR8 expressed in thymus, lung, and kidney, while TLR2 expressed in thymus, lung, and kidney. Expressions of TLRs, i.e., TLR4 and TLR8, and mediators, i.e., MYD88 and ATF3, were upregulated in muscle, PBMCs and PMNs in response to exercise. Expressions of CXCR2 and CCR5 were also upregulated in PBMCs and PMNs after exercise. In the muscle cell line, TLR4 and TLR8 expressions were upregulated when cells were treated with stressors such as cortisol, H2O2, and heat. Migration of PBMCs toward stressed muscle cells was increased by exercise and oxidative stresses, and combinations of these. Treatment with methylsulfonylmethane (MSM), an antioxidant on stressed muscle cells, reduced migration of PBMCs toward stressed muscle cells. Conclusion: In this study, we have successfully cultured horse skeletal muscle cells, isolated horse PBMCs, and established an in vitro system for studying stress-related gene expressions and function. Expression of TLR4, TLR8, CXCR2, and CCR5 in horse muscle cells was higher in response to stressors such as cortisol, H2O2, and heat, or combinations of these. In addition, migration of PBMCs toward muscle cells was increased when muscle cells were under stress, but inhibition of reactive oxygen species by MSM modulated migratory activity of PBMCs to stressed muscle cells. Further study is necessary to investigate the biological function(s) of the TLR gene family in horse muscle cells.