• Title/Summary/Keyword: half-life time

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The effect of oxygen on NAD breakdown in salmonella typhimurium

  • Park, Uhnmee
    • Journal of Microbiology
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    • v.33 no.3
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    • pp.234-238
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    • 1995
  • The breakdown rate of NAD in Salmonella typhimurium was investigated both in aerobic and anaerobic conditions. After NAD is broken down to nicotinamide ring containing moiety, almost all the nicotinamide ring containing moiety recycles back to NAD pool. However almost none of the adenine containing moiety recycles back. We pulse-label the endogeneous NAD with [$\^$14/C]-adenine and [$\^$3/H]- niacin. The remaining [$\^$14/C]-radioactivity in NAD pool at each time was regarded as unbroken portion of NAD, WHERE AS THE OF [$\^$3/H] was served as a total amount of NAD to start with. Under aerobic condition, the half-life of NAD was around 2 hours. However, the breakdown rate was significantly reduced (around 3-5 fold) under anaerobic condition. The observation that under aerobic conditions, NAD turnover is considerably faster than under anaerobic conditions suggests that oxygen has important effect in NAD breakdown.

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CHANGES OF BLOOD PARAMETERS AFTER ESCALATING DOSE OF DA-3021 IN CYNOMOLGUS MONKEY

  • Kim, Choong-Yong;Heo, Jeong-Doo;Han, Su-Cheol;Jo, Yeong-Woo;Chung, Moon-Koo
    • Proceedings of the Korean Society of Toxicology Conference
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    • 2002.11b
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    • pp.194-194
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    • 2002
  • Interferon has therapeutic potential for a wide range of infectious and proliferous disorders such as chronic hepatitis C. However, it has drawbacks such as relatively short serum half-life and rapid clearance like other therapeutic proteins. The attachment of a polyethylene glycol (PEG) moiety to interferon is considered as one of the most promising solutions for its ability to extend the plasma residence time.(omitted)

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A Study on the Dietary Behaviors of Female Baby Boomers and the Needs for Future Perspectives of Dietary Life (여성 베이비부머들의 식생활 태도와 미래 식생활 요구도 조사)

  • Nam, Haewon;Myung, Choonok;Park, Youngsim
    • The Korean Journal of Food And Nutrition
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    • v.26 no.4
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    • pp.895-908
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    • 2013
  • The purpose of this study is to examine female baby boomers' dietary habits and their attitudes together with their needs for future perspectives of dietary life. Our aim is to use these findings as a basic data when forecasting for food-related industries or policy making. A survey is being carried out for a total of 358 female baby boomers and analyzed by SPSS 12.0. The following is a summary of this study. The average age is 52.6 years old, most of them graduated from highschool (63.1%) and had a nuclear type of family (76.1%). Only 39.0% is composed of housewives, others had either full-time or part-time jobs. Self-assessment of stress is not so high and only 8.1% are dissatisfied with their lives. 38.2% are either overweight or obese in terms of BMI, and most of them are non-smokers (97.2%) or non-drinkers (63.0%). Their mean dietary habit scores are $70.6{\pm}11.8$, and the scores show significant relations with their education levels (p<0.01), monthly income (p<0.01), life satisfaction rates (p<0.001), stress levels (p<0.001), smoking habits (p<0.05), drinking habits (p<0.05), regular exercises (p<0.001) and regular health check-ups (p<0.05). The rate of skipping breakfast, lunch and dinner are 18.2%, 1.1%, 5.2% respectively. The main reason for skipping breakfast is the 'lack of time'. With regards to the frequency of grocery shopping, almost half of the subjects (55.7%) said '1~2 times per week' and bought mainly raw food sources such as vegetables, fruits, and meats. The majority of the subjects (91.3%) report that they cooked meals at homes, and took about 1 hour of time. The subjects also point out that cooking was a bothering task, and only 46.4% would prepare meals at home, while others would rather eat out or eat convenience foods. The main reasons for not wanting meal services in the elderly welfare facility are because they didn't want to live such places (48.4%) and the meals are tasteless (31.3%). As for delivery meal services, 60.1% are aware of it, and 39.9% would consider using it in the future. Factors to be considered when using the delivery meal service are sanitation (43.7%), nutrition (28.7%), taste (18.4%), price (6.3%), and brand name (2.9%). This study is expected to be used as useful information when developing food-related strategies for baby boomers in the future.

Residual Characteristics of Bifenthrin and Imidacloprid in Squash (Bifenthrin과 Imidacloprid의 호박 중 관류특성)

  • Lee, Eun-Young;Noh, Hyun-Ho;Park, Young-Soon;Kang, Kyung-Won;Lee, Kwang-Hun;Lee, Jae-Yun;Park, Hyo-Kyung;Yun, Sang-Soon;Jin, Chung-Woo;Han, Sang-Kuk;Kyung, Kee-Sung
    • The Korean Journal of Pesticide Science
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    • v.13 no.2
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    • pp.79-86
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    • 2009
  • In order to elucidate the residual characteristics of the insecticides, bifenthrin and imidacloprid, the pesticides were sprayed onto the squash and their residues were analyzed with GC-ECD and HPLC. Detection limits of the pesticides were $0.005\;mg;kg^{-1}$ and recoveries of bifenthrin and imidacloprid in squash were from 100.87 to 104.31 and from 79.71 to 92.54%, respectively. Half-lives of bifenthrin and imidacloprid in squash were from 1.8 to 2.9 and from 1.5 to 2.5 days, respectively. Initial concentration of bifenthrin and imidacloprid sprayed at the recommended rate and double rate of recommendation were less than their MRLs. And also, residueal concentrations of the pesticides were rapidly decreased in squash with time. At harvest, estimated daily intakes (EDIs) of the pesticides were less than 0.6% of their acceptable daily intakes (ADIs).

Evaluation of Dosimetric Effect and Treatment Time by Plan Parameters for Endobronchial Brachytherapy

  • Choi, Chang Heon;Park, Jong Min;Park, So-Yeon;Kang, SungHee;Cho, Jin Dong;Kim, Jung-in
    • Progress in Medical Physics
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    • v.28 no.2
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    • pp.39-44
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    • 2017
  • This study aims to analyze dose distribution and treatment time of endobronchial brachytherapy (EBBT) by changing the position step size of the dwell position. A solid water phantom and an intraluminal catheter were used in the treatment plan. The treatment plans were generated for 3, 5, 7, and 10 cm treatment lengths, respectively. For each treatment length, the source position step sizes were set as 2.5, 5, and 10 mm. Three reference points were set 1 cm away from the central axis of the catheter, along the axis, for uniform dose distribution. Volumetric dose distribution was calculated to evaluate the dosimetric effect. The total radiation delivery time and total dwell time were estimated for treatment efficiency, which were increased with position step sizes. At half-life time, the differences between the position step sizes in the total radiation delivery time were 18.1, 15.4, 18.0, and 24.0 s for 3, 5, 7, and 10 cm treatment lengths, respectively. The dose distributions were more homogenous by increasing the position step sizes. The dose difference of the reference point was less than 10%. In brachytherapy, this difference can be negligible. For EBBT, the treatment time is the key factor while considering the patient status. To reduce the total treatment time, EBBT can be performed with 2.5 mm position step size.

Rosenvingea orientalis (Scytosiphonaceae, Phaeophyceae) from Chiapas, Mexico: life history in culture and molecular phylogeny

  • West, John A.;Zuccarello, Giuseppe C.;Pedroche, Francisco F.;De Goer, Susan Loiseaux
    • ALGAE
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    • v.25 no.4
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    • pp.187-195
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    • 2010
  • The genus Rosenvingea is well known in the tropics. Four species have been reported from Pacific Mexico: R. floridana, R. antillarum, R. intricata and R. sanctae-crucis. We collected a plant (Boca del Cielo, Chiapas) that we identified as Rosenvingea orientalis, a species not previously reported from Pacific Mexico. We were able to characterize the life cycle of this species for the first time in laboratory culture. It reproduced exclusively by plurilocular sporangia (plurangia). The mature plants were up to 6 cm long with cylindrical to compressed fronds (to 2 mm wide) with dichotomous branches in the upper half of the thallus. The medulla was hollow with 2-3 layers of large inflated colourless cells at the periphery. The cortex was comprised of 1 layer of small cells, each with a single chloroplast and pyrenoid. Linear plurangial sori with phaeophycean hairs formed along the mature fronds. Zoospore germlings developed into prostrate filamentous systems, each with a single phaeophycean hair that gave rise to a single erect shoot with multiple hairs arising near the tip. Molecular phylogeny using the psaA gene placed this isolate within the Scytosiphonaceae. It does not confirm the exact identification of R. orientalis, although its placement close to other Rosenvingea sequences was confirmed and morphological evidence supports its placement in R. orientalis. Our culture investigations indicated that it has an asexual life cycle. Further collections are needed to resolve the full generic and specific relationships of Rosenvingea and related taxa, and their reproductive patterns.

Evaluation of Common Activity and Life in Swedish Cohousing Units

  • Choi, Jung-Shin;Paulsson, Jan
    • International Journal of Human Ecology
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    • v.12 no.2
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    • pp.133-146
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    • 2011
  • This study evaluates common activity and quality of life in Swedish cohousing units to examine whether Swedish cohousing functions properly or not. A questionnaire survey was fulfilled during the autumn of 2010 in G$\ddot{o}$teborg Sweden. The subjects of study were 12 of 44 cohousing units in Sweden that included 4 of the +40 cohousing and 8 of the mixed-age cohousing. A total of 242 of 353 distributed questionnaires were collected (68.6%) and analyzed by SPSS statistical program. The findings are as follow: 1) General characteristics of the respondents are that they are mostly healthy, evenly aged from age 50s to 70s and highly educated with significant proportions of academics and civil workers. There are more females than males and more singles than cohabitants. 2) The most frequent and preferred common activity is a common meal followed by a coffee meeting. A common dinner, the 'hub of living together' is held almost every day or at least a few times a week. A common meal is considered one of the most important activities because of practical and social advantages in that residents can save time and cooking costs as well as engage in social contact. Referring to evaluation of frequency and content of common activity, more than a half of the respondents prefer the current situation. 3) All of the variables (except health conditions and education level) affect participation in common activity with statistical significance. 4) Most of the respondents indicate a high level of life satisfaction and are willing to recommend others move to cohousing. They agree that there is more mutual support among residents in cohousing units than in a conventional community. In conclusion, Swedish cohousing units function successfully as they have pursued intentional community ideology and most of the residents are proud of their current living situations.

Thorough Analysis of Chinese Cultural Heritage Based on Pyohaerok (由 《漂海録》 看中国文化传承的分析)

  • Choi, Chang Won
    • Industry Promotion Research
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    • v.1 no.2
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    • pp.121-128
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    • 2016
  • Cultural heritage means a great lot to a nation's social system and its people's behavior consciousness and plays an important role in its self-development and improvement. It is essential for a nation's self-education and renewal. Improper cultural heritage will be disastrous because it may fall a nation into a loss of terrible chaos. Only the proper cultural heritage can make it always self-awaking, self-correcting and remaining vital in life. This paper, from the perspective of Choi Bu's Pyohaerok, makes a thorough analysis of the unbalance heritage of Chinese ancient culture for thousands of years. For example, many fine traditions gradually vanished in our actual life or only take half their life in heritage nowadays, such as our ancient broad and profound Confucian etiquette, ancient exquisite brocade art and architecture, ancient advanced ship-building technology and many other advanced numerous technological inventions; however, too much unwanted cultural rubbish keeps constant prevailing and takes repeated successions in the life, such as the heavy-form-and-light-content management mode, borrowing power to do evil, neglecting technological inventions long time and generally believing in ghost theory,etc.. This paper mainly focuses on the partial successions of the bad cultural heritage and its bad influence on the country, and concludes that it is just that that makes the country more and more backward. Therefore, the paper makes some pondering over these issues and proposes some related ideas of country-building to attract others participation to deal with them.

Persistence of Fungicide Pencycuron in Soils (토양 중 살균제 Pencycuron의 잔류 특성)

  • An, Xue-Hua;An, Wen-Hao;Im, Il-Bin;Lee, Sang-Bok;Kang, Jong-Gook
    • The Korean Journal of Pesticide Science
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    • v.10 no.4
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    • pp.296-305
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    • 2006
  • The adsorption and persistence of pencycuron {1-(4-chlorobenzyl) cyclopentyl-3-phenylurea} in soils were investigated under laboratory and field conditions to in order to assess the safety use and environmental impact. In the adsorption rate experiments, a significant power function of relation was found between the adsorbed amount of pencycuron and the shaking time. Within one hour following the shaking, the adsorption amounts in the SCL and the SiCL were 60 and 65% of the maximum adsorption amounts, respectively. The adsorption reached a quasi-equilibrium 12 hours after shaking. The adsorption isotherms followed the Freundlich equation. The coefficient (1/n) indicating adsorption strength and degree of nonlinearity was 1.45 for SCL and 1.68 to SiCL. The adsorption coefficients ($K_d$) were 2.31 for SCL and 2.92 to SiCL, and the organic carbon partition coefficient, $K_{oc}$, was 292.9 in SCL and 200.5 inSiCL. In the laboratory study, the degradation rate of pencycuron in soils followed a first-order kinetic model. The degradation rate was greatly affected by soil temperature. As soil incubation temperature was increased from 12 to $28^{\circ}C$, the residual half life was decreased from 95 to 20 days. Arrhenius activation energy was 57.8 kJ $mol^{-1}$. Furthermore, the soil moisture content affected the degradation rate. The half life in soil with 30 to 70% of field moisture capacity was ranged from 21 to 38 days. The moisture dependence coefficient, B value in the empirical equation was 0.65. In field experiments, the half-life were 26 and 23 days, respectively. The duration for period of 90% degradation was 57 days. The difference between SCL and SiCL soils varied to pencycuron degradation rates were very limited, particularly under the field conditions, even though the characteristics of both soils are varied.

A Study on Furniture Design Adopted from a Natural Phenomenon - Focusing on Symbolic Formativeness from the Changing Shapes of the Moon - (자연현상을 활용한 가구디자인 연구 - 달의 형태변화에 따른 상징적 조형성을 중심으로 -)

  • Park, Eun-Min;Yoon, Yeoh-Hang
    • Journal of the Korea Furniture Society
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    • v.26 no.1
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    • pp.12-21
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    • 2015
  • This is a study and work of furniture design adopted from a natural phenomenon, especially from the changing shapes of the moon. The drawer of furniture, a part frequently contacted with our hand (human body) is well related to the symbolism of the moon, which includes life conception and fertility. I created various forms of drawer handle shaped from the moon phases, which give a furniture design esthetical, symbolic and formative meanings. The characteristics of my drawer furniture designs are classified into 3 types. First, as the volumes of drawers increase, the handle shapes also change differently: old moon, crescent, half moon and full moon. Second, without keeping time order, drawers may have the same sizes with handles freely selected and arranged by formative accounts. Third, both increasingly changing type and freely selected and arranged type are combined to make a composite structure. In their simple geometric forms, these furnitures can provide nature intimacy, which fulfill the needs of our time.