• Title/Summary/Keyword: half-lives

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Effect of Bagging Technique on the Residue Patterns of Thiacloprid and Lufenuron in Grape fruit (Vitis labrusca L.) (포도 중 Thiacloprid와 Lufenuron의 유/무대 차이에 따른 잔류량 비교)

  • Jin, Yong-duk;Lim, Sung-Jin;Kim, Sang-Su;Choi, Geun-Hyoung;Lee, Hak-won;Jeong, Du-yun;Moon, Byung-Cheol;Ro, Jin-ho
    • The Korean Journal of Pesticide Science
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    • v.21 no.1
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    • pp.42-48
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    • 2017
  • This study was conducted to compare the effect of bagging technique on the presence of pesticide residues in various parts of grape fruit (whole fruit, pulp and peel). The tested pesticides were diluted at 2,000 times and sprayed three times onto the crops at an interval of seven days and then they were collected at 0, 1, 3, 5 and 7 days after final application. Later, bagging/non-bagging samples were pre-treated with fruit, pulp and peel samples, respectively. Thiacloprid and lufenuron were not detected in any of the bagging samples. The thiacloprid residues of non-bagging samples in whole, peel and pulp samples were 0.47-1.09, 0.18-0.33 and 1.24-1.67 mg/kg, respectively. The lufenuron residues of non-bagging samples in whole fruit, peel and pulp samples were 0.16-0.62, < LOD-0.08 and 0.85-1.48 mg/kg, respectively. The biological half-lives of thiacloprid and lufenuron in whole fruit, peel and pulp of non-bagging samples were 5.7, 15.1 and 7.8 days and 4.0, 9.4 and 2.6 days, respectively. While the unbagged samples showed a sequential decrease in pesticide residues, this study concludes that bagging would be an effective method to protect the presence of thiacloprid and lufenuron residues in grape fruits.

Kinetics of Metolachlor Degradation by Zerovalent Iron (Zerovalent Iron에 의한 Metolachlor의 분해 Kinetics)

  • Kim, Su-Jung;Oh, Sang-Eun;Yang, Jae-E.
    • Korean Journal of Environmental Agriculture
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    • v.26 no.1
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    • pp.55-61
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    • 2007
  • Metolachlor may pose a threat to surface and ground water qualities due to its high solubility in water, Zerovalent iron (ZVI) releases $e^-$ which can degrade the organochlorinated compounds. The objective of this research was to evaluate the kinetics of metolachlor degradation as affected by ZVI sources [Peerless unannealed (PU) and Peerless annealed (PA)] and ZVI levels (1 and 5%) under batch conditions at different metolachlor concentrations (200 and 1000 mg/l) and temperatures (15, 25, and $35^{\circ}C$). The effectiveness of ZVI on metolachlor degradation was assessed by characterizing the dechlorinated metolachlor byproduct molecules. Metolachlor degradation by ZVI followed the first-ordered kinetics with a higher rate constant at higher level of ZVI treatment. At 5% (w/v) of PU and PA treatment, the half-lives of metolachlor degradation were 9.93 and 6.51 h and all of the initial metolachlor were degraded in 72 and 48 h, respectively. Rate constants (k) of metolachlor degradation were higher at the lower initial metolachlor concentration. The metolachlor degradation by ZVI was temperature dependent showing that the rate constant (k) at 15, 25, and $35^{\circ}C$ were 0.0805, 0.1017, and 0.3116 /h, respectively. The ZVI-mediated metolachlor degradation yielded two byproduct molecules identified as dechlorinated metolachlor $(C_{13}H_{18}NO)$ and dechlorinated-dealkylated metolachlor $(C_{12}H_{17}NO)$. The PA ZVI was more effective than PU ZVI in metolachlor degradation.

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.

A Study of Disabled Women's Job Needs (여성장애인의 취업 욕구 수준에 영향을 미치는 요인에 대한 분석)

  • Kim, Ki-Tae;Park, Byung-Hyun;Kang, Chul-Hee;Lee, Sung-Kyu;Lee, Kyung-Hee
    • Korean Journal of Social Welfare
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    • v.37
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    • pp.33-66
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    • 1999
  • The primary objectives of this research is to identify (1) demographic characteristics and job needs of women with disabilities in Korea and (2) factors that predicts the degrees of their job needs. This study uses the data based on interviews with 805 disabled women selected randomly from the registered disabled women in Seoul, Kuyngki-Do, Pusan, and Kuyngsangnam-Do. In the aspect of disabilities, this study showed that more than half of disabled women in our sample have very severe disabilities (1st degree and 2nd degree of disabilities) and needs others' help in their daily lives. In the demographic aspect, this study found that disabled women's education level is very low and their monthly income is also very low. This study also found that in spite of their disabilities and functional limitations, more than 3/4 of disabled women have needs about jobs. Finally, using logistic regression analysis, this study found that disabled women's type of disabilities, dependencies in daily life, age, job experiences, job training experiences, willingness for independence, and parental attitude about disabled women's future are statistically significant in predicting the degree of their job needs. This study will contribute to developing knowledge about disabled women's characteristics and provide practical implications for intervention strategies and assistance programs related to promoting their welfare.

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Characteristics and Stability of the Color of the Cranberry Solution (크랜베리 수용액 색상의 특성 및 안정성)

  • 김진현;이재하;백창규
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.32 no.6
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    • pp.806-811
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    • 2003
  • Effects of pH, temperature, light, sugars, organic acids, metal ions, ascorbic acid, thiamine nicotinic acid and pyridoxine on the stability of the color of the cranberry solution were investigated. The pH had marked influences on the color of the cranberry solution: i.e., the color of the cranberry solution was more intense at low pH. It showed characteristic bathochromic shift as the pH of the solution increased. The half-lives of olor value were 34 days at 37$^{\circ}C$, 91 mins at 9$0^{\circ}C$ and 29 mins at 12$0^{\circ}C$. Light gave an adverse effect to the stability of the color. The color degradation can be minimized by shielding the light from the cranberry solution. Among the sugars tested, fructose was the most deleterious followed by sucrose, galactose, maltose and glucose. Fumaric acid was found to be the most effective in stabilizing the color followed by citric acid, malic acid, acetic acid, while tartaric acid was found to be deleterious. Among the metal ions tested N $a^{+}$ and $Mg^{2+}$ were found to be effective in stabilizing the color, while M $n^{2+}$ was found to be the most deleterious followed by F $e^{2+}$, $K^{+}$ and $Ca^{2+}$. Ascorbic acid was found to be deleterious considerably followed by thiamine, while nicotinic acid and pyridoxine were found to be effective in stabilizing the color feebly.or feebly.

A Study on the Globalization of Services Under the WTO System. (WTO 통상환경 하에서 서비스부문의 세계화 모드에 관한 고찰)

  • Chae, Dae-Seok
    • International Commerce and Information Review
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    • v.7 no.3
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    • pp.287-300
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    • 2005
  • The globalization of services is closely related to other economic problems facing the world today. These are: 1) the globalization of economic activities, 2) the servicization of economic activities. The world economy is now move interconnected than at any time in its history. Investment decisions, production processes, labor market regulations and even environmental legislation made by one country or company affect other economies, other companies and the lives of individuals. In fact, it is nearly impossible to think of a country that is not connected to the world economy in some form or another and it is no exaggeration to state that globalization is already an unassailable fact. The fabric of our economy and the way we do business are changing. This change is the transformation from a marketplace on goods to one focused on services. That is to say, we live and work in a service-centered, service-sensitive economy. As a result of the globalization an servicization of economic activities, services require the globalization, and services are increasing their international trade, foreign investment, agreements, alliances, mergers and collaboration networks. It is quite obvious that services are affected by globalization ; but raising the question by how much leads us to the paradox of service globalization, services represent 70% of the most advances economies but only account for less than 25% of international trade and almost half of direct investment; mergers and takeovers. These figures create a paradox that can be explained by two reasons. First; the natural(the service relationship) and artificial difficulties(barriers to trade) faced by the service sector that inhibits globalization. Second, the non-inclusion in official statistics of the share of internationalized goods that are due to services, for example intra-firm trade or the service value incorporated into exported goods. If these were taken into account the service trade figures would be extremely different. The first explanation can be subdivided into a number of elements. The OECD identifies six reasons:services cannot be stored; client-supplies interaction requires local presence; most service firms are SEMs; products are highly differentiated; cultural differences are especially important in this field; and, finally, trade barriers and restrictions on local operations exist. However, despite all of this, globalization produces clear advantages to suppliers. Therefore, the objective of this study is to explore the main forms of service globalization and differences between that of goods, and is to identify distinctive aspects of service globalization within the framework of the global economy.

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Pharmacokinetics and Bio-distribution of New Gd-complexes of DTPA-bis (amide) (L3) in a Rat Model (쥐를 이용한 새로운 가돌리늄 조영제 Gd-DTPA-bis(amide)(L3)의 약동학 및 생체내 분포 특성에 대한 연구)

  • Yan, Gen;Wu, Renhua;Chang, Yongmin;Kang, Duksik
    • Investigative Magnetic Resonance Imaging
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    • v.17 no.4
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    • pp.259-266
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    • 2013
  • Purpose : To investigate the blood pharmacokinetics and bio-distribution of DTPA-bis-amide (L3) Gd(III) complexes. Materials and Methods: The pharmacokinetics and bio-distribution of Gd $(L3)(H_2O){\cdot}nH_2O$ were investigated in Sprague-Dawley rats after intravenous administration at a dose of 0.1 mmol Gd/kg. The Gd content in the blood, various tissues, and organs was determined by ICP-AES. Blood pharmacokinetic parameters were calculated using a two-compartment model. Results: The half-lives of ${\alpha}$ phase and ${\beta}$ phase Gd $(L3)(H_2O){\cdot}nH_2O$ were $2.286{\pm}0.11$ min and $146.1{\pm}7.5$ min, respectively. The bio-distribution properties reveal that the complex is mainly excreted by the renal pathway, and possibly excreted by the hepatobiliary route. The concentration ratio of Gd (III) was significantly higher in the liver and spleen than in other organs, and small amounts of Gd (III) ion were detected in the blood or other tissues of rats only after 7 days of intravenous administration. Conclusion: The MRI contrast agent Gd $(L3)(H_2O){\cdot}nH_2O$ provides prolonged blood pool retention in the circulation and then clears rapidly with minimal accumulation of Gd(III) ions. The synthesis of gadolinium complexes with well-balanced lipophilicity and hydrophilicity shows promise for their further development as blood pool MRI contrast agents.

Studies on Microbial Penicillin Amidase (Part 5) Application of Reinforced Calcium-Alginate Gel Entrappment Method for Immobilization of Penicillin Amidase from Bacillus megaterium (미생물 페니실린 아미다제에 관한 연구 (제 5보) Bacillus megaterium 페니실린 아미다제의 새로운 고정화 방법)

  • Son, Hyeung-Jin;Seong, Baik-Lin;Mheen, Tae-Ick;Han, Moon-Hi
    • Microbiology and Biotechnology Letters
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    • v.9 no.3
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    • pp.159-164
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    • 1981
  • Reinforced Calcium-alginate gel entrappment method for enzyme immobilization is described with an example of penicillin amidase from Bacillus megaterium KFCC 10029, a partially constitutive mutant of B. megaterium ATCC 14945. Penicillin amidase recovered from the fermentation broth by adsorption on celite is mixed with alginate and gelatin solution, and cast into a pellet or noodle form by coagulation in calcium salt solution followed by crosslinking with glutaraldehyde. Optimum pH and temperature of the immobilized enzyme preparation were 8.0 and 6$0^{\circ}C$, respectively. Kinetic constants such as Km value and the inhibition constant of 6-APA and phenylacetic acid were 2.6 mM, 7.4 mM and 21.2 mM, respectively. The enzyme leakage from the adsorbent during operation was successfully prevented owing to the increase of physical strength of gel coat. The half lives in a column reactor were 6 and 30 days at the respective temperature of 4$0^{\circ}C$ and 3$0^{\circ}C$, which were the 6-8 fold increased values as compared with those of without entrappment. The results highly recommended the use of reinforced Calcium-alginate gel entrappment method for the enhancement of physical strength and the operational stability of alginate gel entrapped enzyme.

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Persistence of Chlorfenapyr in Paprika Leaf and Its Residual Biological Activity to Two Spotted Spider Mite, Tetranychus urticae (파프리카 잎 중 Chlorfenapyr의 잔류량 변화와 점박이응애에 대한 잔효 생물 활성)

  • Cho, Kyu-Song;Lee, So-Jung;Lee, Dong-Yeol;Kim, Yeong-Jin;Kim, Kyoung-Youl;Chung, Bu-Keun;Kang, Kyu-Young
    • The Korean Journal of Pesticide Science
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    • v.15 no.3
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    • pp.317-322
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    • 2011
  • A comparative experiment was conducted to investigate the persistence of chlorfenapyr residue and its biological activity to two spotted spider mite, Tetranychus urticae, after treatment of chlorfenapyr suspension concentrate (10% SC) on paprika plants at recommended (2000 times dilution) and double dosage. Biological half-lives of chlorpfenapyr were estimated as 8 and 5 days in leaves and fruits of paprika plants, respectively. While initial deposits of chlorfenapyr residues in leaves at recommended and double dosages were 22.22 and 37.75 ${\mu}g\;g^{-1}$ at the time of application, its residue decreased to 1.56 ${\mu}g\;g^{-1}$ and 3.62 ${\mu}g\;g^{-1}$ at 29 days after treatment, respectively. Residual biological activity of chlorfenapyr SC to T. urticae at recommended dosage lasted for 7 or 15 days on the basis of 24 or 48-hrs mortality test assayed with feeding on excised leaf chlorfenapyr-treated. The control efficacy to the mite showed a good agreement with the persistence of chlorfenapyr residues in leaves.

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).