• Title/Summary/Keyword: agent model

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The moderating effects of converging smart work and supervisor's support in the study of turnover on job satisfaction in call centers (콜 센터에서 이직요인이 직무만족에 미치는 영향에 있어 스마트워크와 상사지원 융복합 서비스의 조절효과에 관한 연구)

  • Kim, Kye-Chul;Cheong, Ki-Ju
    • Journal of Digital Convergence
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    • v.13 no.4
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    • pp.101-114
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    • 2015
  • The purpose of this study is first to understand agent's turnover from both academic and perspectives. Then we suggest convergence of smart work paradigm and supervisor's support as the relieving factors of turnover, The research model of this study is based upon reviews of turnover literature, the smart work and supervisor's support as moderating variables from which research hypotheses were derived. The data came from the survey from financial sector agents such as banking, insurance, and others. The analyses has been done by SPSS 20.0, We used multiple regressions to test the effects of the tested variables on the dependent variable, job satisfaction. The results of this study find significant relations of smart work and supervisor's supports in relations to personal and job-related turnover. The implication is smart work and supervisor's supports play significant role in increasing job satisfactions. Major finding is too much supervisor's supports ignoring agent's situations may bring reverse effects on relieving turnover.

Pharmaceutical Characteristics of Korean Lumbricus rubellus Lumbrokinase (한국산 지렁이[Lumbricus rubellus]에서 분리한 Lumbrokinase의 약리학적 특성)

  • 조일환;이철규;임헌길;이형환
    • KSBB Journal
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    • v.19 no.4
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    • pp.274-283
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    • 2004
  • Six lumbrokinase (LK) fractions from Lumbricus rubellus lysates were purified by a series of column chromatographies. The molecular weights of the six LK fractions appeared to range from 24.6 to 33.1 kDa. In the experimental model of rat venous thrombosis, the thrombus weight and PAI activity decreased significantly when the LK was administered orally. However, the activities of APTT, PT and plasmin showed a significant increase. The aggregation of rat platelets pretreated with various LK doses was inhibited by thrombin, and the MDA generation decreased. The rat thoracic aorta and mesentric arteries contracted with phenylephrine relaxed due to the treatment of the LK fractions. These results suggest that the fibrinolytic effects of LK were mediated not only by proteolytic activity, but also by the inhibition of platelet agregation and the relaxation of blood vessels. It is concluded that the LK may be useful as a hemolytic agent for treatment of fibrin clot.

Cost Effectiveness Analysis of Different Management Strategies between Best Supportive Care and Second-line Chemotherapy for Platinum-resistant or Refractory Ovarian Cancer

  • Luealon, Phanida;Khempech, Nipon;Vasuratna, Apichai;Hanvoravongchai, Piya;Havanond, Piyalamporn
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.2
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    • pp.799-805
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    • 2016
  • Background: There is no standard treatment for patients with platinum-resistant or refractory epithelial ovarian cancer. Single agent chemotherapies have evidence of more efficacy and less toxicity than combination therapy. Most are very expensive, with appreciable toxicity and minimal survival. Since it is difficult to make comparison between outcomes, economic analysis of single-agent chemotherapy regimens and best supportive care may help to make decisions about an appropriate management for the affected patients. Objective: To evaluate the cost effectiveness of second-line chemotherapy compared with best supportive care for patients with platinum-resistant or refractory epithelial ovarian cancer. Materials and Methods: A Markov model was used to estimate the effectiveness and total costs associated with treatments. The hypothetical patient population comprised women aged 55 with platinum-resistant or refractory epithelial ovarian cancer. Four types of alternative treatment options were evaluated: 1) gemcitabine followed by BSC; 2) pegylated liposomal doxorubicin (PLD) followed by BSC; 3) gemcitabine followed by topotecan; and 4) PLD followed by topotecan. Baseline comparator of alternative treatments was BSC. Time horizon of the analysis was 2 years. Health care provider perspective and 3% discount rate were used to determine the costs of medical treatment in this study. Quality-adjusted life-years (QALY) were used to measure the treatment effectiveness. Treatment effectiveness data were derived from the literature. Costs were calculated from unit cost treatment of epithelial ovarian cancer patients at various stages of disease in King Chulalongkorn Memorial Hospital (KCMH) in the year 2011. Parameter uncertainty was tested in probabilistic sensitivity analysis by using Monte Carlo simulation. One-way sensitivity analysis was used to explore each variable's impact on the uncertainty of the results. Results: Approximated life expectancy of best supportive care was 0.182 years and its total cost was 26,862 Baht. All four alternative treatments increased life expectancy. Life expectancy of gemcitabine followed by BSC, PLD followed by BSC, gemcitabine followed by topotecan and PLD followed by topotecan was 0.510, 0.513, 0.566, and 0.570 years, respectively. The total cost of gemcitabine followed by BSC, PLD followed by BSC, gemcitabine followed by topotecan and PLD followed by topotecan was 113,000, 124,302, 139,788 and 151,135 Baht, respectively. PLD followed by topotecan had the highest expected quality-adjusted life-years but was the most expensive of all the above strategies. The incremental cost-effectiveness ratios (ICER) of gemcitabine followed by BSC, PLD followed by BSC, gemcitabine followed by topotecan and PLD followed by topotecan was 344,643, 385,322, 385,856, and 420,299 Baht, respectively. Conclusions: All of the second-line chemotherapy strategies showed certain benefits due to an increased life-year gained compared with best supportive care. Moreover, gemcitabine as second-line chemotherapy followed by best supportive care in progressive disease case was likely to be more effective strategy with less cost from health care provider perspective. Gemcitabine was the most cost-effective treatment among all four alternative treatments. ICER is only an economic factor. Treatment decisions should be based on the patient benefit.

Preclinical Study of DA-5018, a Non-narcotic Analgesic Agent

  • Kim, Soon-Hoe
    • Proceedings of the PSK Conference
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    • 2000.04a
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    • pp.70-81
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    • 2000
  • DA-5018 is a synthetic capsaicin derivative under development as a non-narcotic a analgesic ag$\varepsilon$nt. DA-50 18 showed a potent analgesic activity against acute and chronic pain m model(Tablel, 2.), but it had a narrow margin of safety. DA-5018 did not bind to opioid(${\kappa}, {\delta}, {\mu}$), NKl, CGRP receptors in vitro and its analgesic effect was not antagonized by naloxone, a and it did not develop analgesic tolerance. In addition DA-5018 had no inhibitory effects against c cyclooxygenase and 5-lipooxygenase activities. DA-5018 significantly increased the relcase of substance P from the slices of the rat spinal cord. These results suggest that DA-50 18 is not a narcotic nor aspirin-like analgesic and the release of substance P is one of analgesic mechanism of action of DA-5018. We found that DA-5018 was almost ten times more potent and was at l least IOO-times less irritable compared to capsaicin. Accordingly development of topical formula was adopted. Topical formula was desiged and screened by flux test of DA-5018 using hairless mouse skin and several formulas were selected. With these topical formulas we a assessed the analgesic efficacy and carried out the toxicity, skin irritation and pharmacokinetic studies. In streptozotocin-induced hyperalgesic rat and 50 % galactose-fed hyperalgesic rat as diabetic pain models, DA-5018 cream increased the pain thresh이ds up to 77.0% and 24.4% respectively, while Zostrix-HP(capsaicin cream) incr$\varepsilon$as cd by 65.9% and 21.0%. DA-5018 c cream showed a good analgesic effect as welI in FCA-induced arthritic rat. DA-5018 cream did not show any toxicological signs in acute and chronic toxicity test and had little skin irritation in car swclIing and scratching t$\varepsilon$st. Pharmacokinetics of DA-50 18 were studied after topical application of ${14}^C$-Iabelled or unlabelIed DA-5018 cream. Plasma and skin concentrations c except applied skin wcre below the dctection limit and after 7-day cummulative application, plasma concentrations were also below detection limit DA-50 18 may have an advantag$\varepsilon$ ov$\varepsilon$r c capsaicin and is now being developed as a topical agent for the treatment of pains. DA-50 18 cream was approved for Korean IND and is now under a Phase II clinical study for arthritic pain a after finising Phase I study. DA-50 18 was also liscensed out to Stiefel Company in America in

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$^{99m}Tc-Labeling$ of Monoclonal Antibody to Carcinoembryonic Antigen and Biodistribution (항 암태아성항원에 대한 단세포군항체의 $^{99m}Tc$ 표지법개발 및 생체분포)

  • Moon, Dae-Hyuk;Chung, June-Key;Lee, Myung-Chul;Koh, Chang-Soon;Chung, Hong-Keun;Park, Jae-Gahb
    • The Korean Journal of Nuclear Medicine
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    • v.26 no.2
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    • pp.380-391
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    • 1992
  • This study was designed to evaluate a direct method of $^{99m}Tc$ labeling using $\beta-mercaptoethanol$ as a reducing agent, and to investigate whether $^{99m}Tc$ labeled specific monoclonal antibody against carcinoembryonic antigen (CEA-92) can be used for the scintigraphic localization of human colon cancer xenograft. Purified CEA-92 IgG was fragmented into F $(ab')_2$ and then labeled with $^{99m}Tc$ by transchelation method using glucarate as a chelator. Labeling efficiency, immunological reactivity and in vitro stability of $^{99m}Tc$ CEA-92 F $(ab')_2$ were measured and then injected intravenously into nude mice bearing human colon cancer (SNU-C4). Scintigrams were obtained at 24 hour after injection. Then nude mice were sacrificed and the radioactivity was measured Labeling efficiency of injected $^{99m}Tc$ CEA-92 F $(ab')_2$, immunoreative fraction and in vitro stability at 24 hour of injected $^{99m}Tc$ CEA-92 F $(ab')_2$ was 45.2%, 32.8% and 57.4%, respectively. At 24 hour after injection, % ID/g in kidney (46.77) showed high uptake, but %ID/g in tumor (1.65) was significantly higher than spleen (0.69), muscle (0.16), intestine (0.45), stomach (0.75), heart (0.48) and blood (0.45). There was no significant difference between tumor and liver (1.81). Tumor contrast as quantitated by tumor to blood ratio of $^{99m}Tc$ CEA-92 F $(ab')_2$ was increased significantly (p<0.005) until 24 hours (3.70), and there was no statistical differece from tumor to blood ratio of I-131 CEA-92 F $(ab')_2$. The scintigram demonstrated localization of radioactivity over transplanted tumor, but significant background radioactivity was also noted over kidney and abdomen. It is concluded that CEA-92 F $(ab')_2$ can be labeled with $^{99m}Tc$ by a direct transchelation method using $\beta-mercaptoethanol$ as a reducing agent and $^{99m}Tc$ labeled CEA-92 F $(ab')_2$ can be used for the scintigraphic localization of human colon cancer xenograft in nude mice model.

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5-Aza-2'-deoxycytidine Inhibits the Maintenance of Cancer Stem Cell in a Mouse Model of Breast Cancer (마우스 유방암 모델에서 5-Aza-2'-deoxycytidine의 암줄기세포 유지 억제 효과)

  • Nho, Kyoung-Jin;Yang, In-Sook;Kim, Ran-Ju;Kim, Soo-Rim;Park, Jeong-Ran;Jung, Ji-Youn;Cho, Sung-Dae;Nam, Jeong-Seok
    • Journal of Life Science
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    • v.19 no.8
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    • pp.1164-1169
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    • 2009
  • Aberrant DNA methylation plays an important role in the development of cancer. It has been reported recently that DNA hypermethylation is involved in the maintenance of cancer stem cells. The present study was designed to test the hypothesis that the demethylating agent, 5-aza-2'-deoxycytidine (AZA), can inhibit the potential for maintenance of cancer stem cells. To validate this hypothesis, we used 4T1 syngeneic mouse models of breast cancer. The AZA pre-treated 4T1 cells showed a dramatic inhibition of tumorsphere formation, compared to their counterparts in vitro. In addition, the AZA treatment significantly suppressed the expression of stem regulator genes, such as oct-4, nanog and sox2, compared to counterparts in vivo. Therefore, selective inhibition of DNA methylation may be useful for stem-specific cancer therapy.

Differential Diagnosis of Chemical-induced Hepatobiliary Toxicities Using a New Hepatobiliary Imaging Agent in Mice

  • Ryu, Chong-Kun;Pie, Jae-Eun;Choe, Jae-Gol;Cheon, Joon;Sohn, Jeong-Won;Jurgen Seidel;David S. Paik;Michael V. Green;Chang H. Paik;Kim, Meyoung-Kon
    • Environmental Mutagens and Carcinogens
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    • v.21 no.1
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    • pp.1-8
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    • 2001
  • We have synthesized $^{99m}$Tc-mercaptoacetyltriglycine (MAG3)-biocytin as a new imaging agent for hepatobiliary scintigraphy. The aim of this study was to evaluate the usefulness of $^{99m}$Tc-MAG3-biocytin scintigraphy in differentiating carbon tetrachloride ( $CCl_4$)-induced hepatotoxicity from $\alpha$-naphthylisothiocyanate (ANIT)-induced cholestasis in mice, which reflecting the differential diagnosis of neonatal jaundice caused by neonatal hepatitis from congenital biliary atresia in humans. Methods: Balb/c mice (female, 20 g, n=4-6) were pretreated with $CCl_4$(0.5 or $1.0m\ell$/kg) and ANIT ($150 or 300 m\ell$/kg) 18 h before scintigraphy. Biochemical and histopathological examinations showed a pattern of typical acute hepatitis (increase of transaminases and hepatocellular necnsis) in $CCl_4$-treated mice and cholestasis (increase of alkaline phosphatase and ${\gamma}$-glutamyltransferase, and biliary hyperplasia) in ANIT-treated mice, respectively, Mice were fasted at least 4 hr prior to the intravenous injection of $^{99m}$Tc-MAG3-biocytin (18.5 MBq/20$\mu\textrm{g}$) in 2% human serum albumin in saline. Scintigraphy was performed with a ${\gamma}$-camera equipped with a 1-mm diameter pin-hole collimator for 30 min and images were acquired every 15 s. We compared the values of physical parameters, such as peak liver/heart ratio ($${\gamma}$_{max}$) and peak ratio time ($t_{max}$) far $^{99m}$Tc-MAG3-biocytin scintigraphy. Results: Scintigraphic parameters of the $CCl_4$-pretreated (0.5 $m\ell$/kg) group showed a 81.9% decrease of r$_{max}$, and 42.2% decrease of $t_{max}$, whereas the ANIT-pretreated ( $150m\ell$/kg) group showed a 53% decrease of $r_{max}$, and 2.36-fold increase of $t_{max}$, (P<0.05). These results demonstrate that the decrease of $r_{max}$ and the shortening of $t_{max}$ are characteristic features for hepatotoxicity, in contrast to the increase of $t_{max}$ and decrease of $r_{max}$ for biliary hyperplasia. Conclusion: $^{99m}$Tc-MAG3-biocytin hepatobiliary scintigraphy can distinguish hepatitis from cholestasis in mice model and may be similarly useful in humans which differentiating the cause of neonatal jaundice in clinical study.cal study.cal study.cal study.

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A Study on the Preventive Measures against Fall Injuries in Manufacturing Industry Focusing on the Portable Ladders (이동식 사다리를 중심으로 한 제조업에서의 추락재해 예방대책 연구)

  • Kim, Hyung-Seok;Lee, Seok-Won;Jung, Won-Jae;Ryu, Bo-Hyuk
    • Journal of the Korean Society of Safety
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    • v.24 no.6
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    • pp.136-143
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    • 2009
  • The injuries as a result of fall accidents is the one of the most common kind of injuries in Korea, especially fall from height is the top most common kind for fatal injuries. Futhermore, the number of fall injuries in manufacturing industry has been steadily increasing from 2000 to 2007. In 2007 the number of fall fatal injuries increased 10.6 % in comparison with the number in 2006. These numbers are 6~17 times higher than those for foreign countries such as the U.K and the USA. So, it is needed to make a study to reduce these numbers for manufacturing industry. To get the goals, we did research as followings. First, this study analyzed statistics by industry, by fall height, by common agent and so on to gain an insight into real aspect of fall injuries. It showed that ladder is the commonly cited agent for manufacturing industry, and 3 risky activities ; the ladder work, the load/unload work, and the maintenance work. Secondly, this study made a survey of manufacturing workers for their understandings of the most 3 risky activities. It showed that 'tendency to work easily' and 'difficulty of applying measures due to inherent working conditions' are main reasons for workers not to implement the preventive measures against the fall accidents. Thirdly, this study tested the slip characteristics of ladder base and lungs. The tests were done based on ANSI standard and KS. In addition to the standard condition, this study performed slip tests in wet and sandy conditions and compared the results with the those of standard condition. It showed that friction coefficient is standard condition > wet condition > sandy condition, and the friction coefficient of ladder for sandy condition is measured to be reduced by 63.9% compared with that for standard condition. Finally, this study developed safety work models for using of portable ladders in consideration of the safety standards of foreign countries such as the U.K, the USA, and the Australia.

Prediction of the Minimum Required Pressure of Soundless Chemical Demolition Agents for Plain Concrete Demolition (무근콘크리트 해체시 무소음화학팽창제의 최소요구팽창압 예측)

  • Kim, Kyeongjin;Cho, Hwangki;Sohn, Dongwoo;Koo, Jaehyun;Lee, Jaeha
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.31 no.5
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    • pp.251-258
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    • 2018
  • In construction site, conventional methods such as jackhammer or explosive methods(dynamite) have been often used for the demolition of structures. Use of those methods are more carefully treated in environmentally and historically sensitive area. For those reasons, use of Soundless Chemical Demolition Agent(SCDA) is getting the spotlight. The SCDA is a powder which has expansive strength when it is mixed with water. In these Characteristics, SCDA can destroy the concrete or rock as it is poured into boreholes of the concrete or rock structures. However, there is no industrial standard for the use of SCDA effectively yet. In this study, experimental study to measure the expansive pressure was conducted depending on various boundary conditions such as waterproof, length of the steel pipe, submerged of steel pipe. Furthermore, computational analysis using damage plasticity model to predict the minimum required pressure of the SCDA for the concrete demolition depending on spacing between holes(k-factor) and compressive strength of the concrete was conducted. Obtained results indicates that water heat dissipation with submerged steel pipe shows the stable pressure for measuring the SCDA and hole distance(k-factor) is the most important factor for crack initiation of concrete.

Information Mediating in Social Network Sites : A Simulation Study (소셜 네트워크 사이트의 정보 매개하기 : 시뮬레이션 연구)

  • Rho, Sangkyu;Kim, Taekyung;Park, Jinsoo
    • The Journal of Society for e-Business Studies
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    • v.18 no.1
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    • pp.33-55
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    • 2013
  • Information sharing behavior in the Internet has raised much interest. Recently, social network sites provide a new information sharing channel for the users who want to connect with others based on common social background or tastes. Especially, we focus that a social network site becomes one of major routes for information sharing about socially influential issues. Therefore, studying how information is diffused via a social network site may give theoretically, practically significant implication. Based on the assertion, we investigated user's behavior to mediate other user's information messages. We define information mediating behavior as concurrent actions of filtering and distributing behavior of the digital content that is originated from one of the connected users. In this study, we intended to understand the effects of information mediating behavior, and tried to understand characteristics of re-mediating of previously mediated information. Using an agent-based simulation model, we found that information mediating behavior increased the extent of information diffusion significantly. In addition, even a small degree of mediating probability could boost up the level of information diffusion in the case of a re-mediating condition. We believe that those findings provide remarkable insight of research and business application on both of information sharing and diffusion in a social network site.