• Korean Journal of Environmental Biology
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• v.26 no.3
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• pp.129-137
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• 2008

Alien apple snails (Pomacea canaliculata, Pomacea insularus) used in environmentally-friendly agriculture are different from indigenous snails found in Korea. Due to high herbicidal effects and cost-effectiveness, the number of farmers using the snails has been growing every year since 2000. Moreover, in 2008, because of the outbreaks of avian influenza throughout the country from March to May, 2008, central and local governments recommended the use of alien apple snails in agriculture as an alternative to the ducks-oriented environmentally-friendly agriculture. Therefore, it is expected that the use of alien apple snails in agriculture should be expanded in a near future. Since alien apple snails lay eggs with 95.8% of eclosion rate, they are considered to be potential pests unlike indigenous snails. In addition, Japan, Taiwan and most of the southeast Asian countries had already experienced severe ecological and agricultural damage by the alien apple snails. Subsequently, International Union for Conservation of Nature and Natural Resources (IUCN) designated P. canaliculata as one of "the 100 of the world's worst invasive alien species". It seems highly likely that the alien apple snails in Korea pose a potential threat to conservation of ecosystem and biodiversity since the snails were either found or invaded into the natural environments in some regions of Gangwon-Do and southern parts of Korean Peninsula. However, just recently, agricultural authorities and farmers using alien apple snails in agriculture opposed a proposition of designating the alien apple snails as an ecosystem-disturbing animal described by the Wildlife Protection Act. This is because there has been no concrete evidence of the ecological risk imposed by the alien snails up to now in Korea. Subsequently, in this paper, we analysed the ecological and agricultural risks imposed by the alien snails from the studies done in domestic and abroad. In addition, we proposed an urgent need and reasoning for ecological risk management of the alien snails at the national level as well as using the snails in agriculture.

• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.2
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• pp.149-155
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• 2012

Purpose : Serum insulin levels are useful indicator which of reflecting the function of insulin secretion in pancreatic ${\beta}$ cell and diagnosis of diabetes, differentiating the cause of impaired glucose tolerance. Insulin measurement kits have shown some differences in many ways such as test methods as well as quality control. The purpose of this study was to evaluate the diagnostic performance of seven manufacturing companies commercial kits. Materials and Methods : The values of insulin measured by three manufacturing companies (Biosource, Siemens, TFB) with 59 samples in August 2009 were compared with those measured by four manufacturing companies (Immunotech, Izotope, BNIBT, Cisbio) with 68 samples in December 2011. We evaluated precision, recovery rate, dilution test and correlation of serum insulin measurement using seven manufacturing company kits. Statistical program SPSS 12.0 was used for the verification of results. Results : The coefficients variation of the precision on all seven different kits were showed within 5.0%. Recovery rate of Biosource, Siemens, TFB kits on three different levels showed 94.2~103.7%, 99.0~104.6%, 99.7~107.6% respectively. Immunotech, Izotope, BNIBT, Cisbio were 93.5~99.1%, 91.4~99.1%, 99.2~131.0%, 84.8~102.3% respectively. There was strong correlation between the measurement of insulin by Biosource kit and that by two commercial kits, Siemens (R2=0.96), TFB (R2=0.99). There was good correlation between the measurement of insulin by TFB kit and that by three commercial kits, Immunotech (R2=0.97), Izotope (R2=0.96), Cisbio (R2=0.97). In the dilution test performed with more than 200 ${\mu}IU/ml$ high concentration samples, samples with diabetes correctly was measured in all seven manufacturing kits. However, as measured with insulinoma samples TFB, Siemens, Izotope, Cisbio kits were correctly measured, but Biosource and Immunotech kits were measured 47.4 ${\mu}IU/ml$, 72.3 ${\mu}IU/ml$, respectively. Conclusion : Serum Insulin radioimmunoassay kits were showed excellent precision, correlation and good recovery rate. However, some kits were not measured correctly in the high concentration insulin values. when selecting a kit should be considered many factors that cost effectiveness, compatible for automation equipment, high performance kit, the environment for each laboratory such as reaction time and reporting time.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.10 no.4
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• pp.67-80
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• 2015

Although recent policies and regulations in Korea strongly advocate and encourage cultivation of venture foundations, studies on venture foundation and success are very limited and often primarily focus on entrepreneurship or individual quality as a venture founder in addition to such studies' validity in question. Therefore, this study primarily focuses on venture preparation process which is subject to venture founder's effort to verify the policy effectiveness in the relationship between venture preparation and business performance. Major goal of this study is to reduce social cost of venture failure by suggesting systematic policy support for venture foundations and analyzing the relationship between following variables: first, venture preparation and financial performance, second, venture preparation and non-financial performance, and third, venture preparation and business performance. 400 initial venture foundations less than 5 years are selected from KISED(Korea Institute Startup & Entrepreneurship Development) trend analysis to carry out statistical analysis using SPSS 18.0. To organize the data features, frequency analysis as well as descriptive statistics are performed to verify the hypothesis. As a result, sub-factors in measurement of venture preparation which are venture education period, venture benefit, and experience of incubating organization are selected as independent variables. Likewise, sub-factors in measurement of business performance which are financial performance and non-financial performance are used as dependent variables. To validate interactive effect, venture preparation period is selected as control variable to perform hierarchical regression analysis. The analysis result verifies that venture benefit has positive influence on financial and non-financial performance while venture education period has positive influence on non-financial influence and experience of incubating organization has negative influence on non-financial performance without influence on financial performance. In addition, interaction of venture preparation period has positive influence solely between venture benefit and non-financial performance. Through this study, appropriate supporting plans depending on the level of venture preparation can be derived to improve business performance of initial venture foundations for policy designer of venture support, and quality rather than quality improvement of venture businesses is possible through investigation of structural issues of individual venture businesses. Ultimately, this study suggests venture founders to determine whether to focus on venture preparation process or to start a venture business.

• Journal of Bio-Environment Control
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• v.21 no.2
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• pp.114-119
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• 2012

We have conducted 4 experiments to develop the most environmental and effective use of the two-fluid fog system to prevent and exterminate whiteflies in tomato cultivation. In particular, these experiments used Vitamini tomatoes grown in stand-alone greenhouses at Buyeo Tomato Experiment Station as subjects. Each experiment utilized the fog system in a different way. The first experiment provided the control group, which was subject to the two-fluid fog system without additional humidity control. In the second experiment, the two-fluid fog system controlled the humidity level to be above 70%. The third and the fourth experiment utilized natural substances, which were 1.5 mg/L of Neem Oil and 2 mg/L of Oleic acid respectively, without additional humidity control. From the first experiment, we could observe that a simple use of the two-fluid fog system decreased the density of whiteflies in the greenhouses. This impact of the fog system on whiteflies was greater in the second experiment. By comparing the first and the second experiment, we concluded that whiteflies are more effectively prevented by maintaining a higher humidity level via the fog system's smaller water droplets that float in the air for longer time than the standard fog system in rather dry condition. In the third and the fourth experiments, the extermination level was 78% and 76.4% respectively, comparing only 53% in the first experiment without the humidity control. Therefore, using the natural substances in addition to the humidity control increases the extermination effectiveness. Considering the similar results from the 3rd and the 4th experiments, Oleic acid has a greater appeal for its lower price. Using the two-fluid fog system to both control the humidity on a daily basis and spray the substances for occasional extermination would reduce labor cost and increase production in an environmental way.

• Analytical Science and Technology
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• v.8 no.1
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• pp.91-99
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• 1995

One of alternative conventional technologies used for treatment of livestock wastes is composting process, and recently some mechanical composting processes are being practiced. It is, however, recognized the composting process also has its own limitations such as longer time requirement, and difficulties to estimate the degree of decomposition, etc. The incomplete compost contains potentially harmful materials to crops and public health due to instabilized organic contents and pathogenic organisms. The purpose of this investigation is to develop an innovative system whereby anxious livestock wastes are thoroughly stabilized and disinfected. Thus the overall management scheme should meet the following requirements. 1. A system should be in a cost-effective and environmentally sound manner. 2. Sludges must be chemically stabilized and bacteriologically safe. 3. Odor-free by product should be applied to crop land. 4. Sludges are sources of fertilizer nutrients and/or soil amendments to enhance crop production. 5. And they can be used as potential pH adjusting agent of the acidified soils. Overall effectiveness of the developed system is experimentally tested to satisfy the preset criteria and requirements. Major experiments are divided into four categories: they are 1. chemical stability test, 2. optimal condition test of stabilization process, 3. bacteriological examination and disinfection tests, and 4. deodorization tests The stabilization process is consisted of the stabilizing reaction process and the drying process. Stabilized wastes is dried by both sun dryer and rotary dryer. It is shown that an additive dosage of about g/kg solid in wastes with a minimum of 5-minutes reaction would be necessary for effective stabilization reaction. The stabilization process is consisted of the stabilizing reaction process and drying process. Stabilized wastes are dried by both sun dryer and rotary dryer. It is shown that an additive dosage of about 300g/kg solid in wastes with a minimum of 5-minutes reaction would be necessary for effective stabilization reaction. In the stabilization reaction process, the pH of wastes is lowered from initial values of 12.3 to 8.6. High pH prevents odor production and kills pathogenic organisms. Organic matter contents in the stabilized wastes are about 50% and the sum of contents of fertilizer elements such as total nitrogen, $P_2O_5$ and $K_2O$ are about 5.3%. The livestock wastes that are stabilized chemically and hygienically can be used as a good soil conditioner and/or organic fertilizer.

• Clinical and Experimental Pediatrics
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• v.51 no.11
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• pp.1165-1171
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• 2008

Purpose : This study aimed to identify the true extent of non-responsiveness in full-term infants born from HBsAg-negative or HBsAg-positive mothers and vaccinated against hepatitis B virus (HBV) at 0, 1, and 6 months of age and to evaluate the effect of revaccination among non-responders. Methods : The study included 716 full-term infants born in 2004-2007. Of 716, 662 infants (A group) were born to HBsAg-negative mothers and 54 infants (B group: 50, except HBsAg-positive infants) were born to HBsAg-positive mothers. All infants were administered DNA recombinant vaccines at 0, 1, and 6 months of age. B group infants received hepatitis B immunoglobulin at birth. Anti-HBs titers were tested at 7-12 and 9-15 months in A and B groups, respectively. Three revaccination doses were administered to non-responders whose anti-HBs titers were under 10 mIU/ml; revaccinated infants were retested at 1-3 months after last vaccination. The association between HBeAg seropositivity of mother and the failure of HBV immunoprophylaxis was evaluated. Results : The seroconversion rates after primary hepatitis B vaccination were higher in A group (94.1%) than in B group (78%, P<0.001). The seroconversion rates were high in revaccinated infants (A group non-responders: 96.9%, B group non-responders: 87.5%). The failure of HBV immunoprophylaxis was significantly associated with maternal HBeAg seropositivity (P<0.001). Conclusion : The seroconversion rates after primary hepatitis B vaccination were low in B group infants. Revaccination of non-responders in B group was very effective. Therefore, anti-HBs testing and revaccination of B group is very important. Revaccination of non-responders in A group was also very effective. Thus, testing the immune status of infants born to HBsAg-negative mothers even after primary hepatitis B vaccination should be considered. However, to realize this, further studies on the cost-effectiveness of anti-HBs testing in healthy full-term infants are necessary.

• Clinical and Experimental Pediatrics
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• v.50 no.7
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• pp.636-642
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• 2007

Purpose : Fluconazole prophylaxis for very low birth weight (VLBW) infants has been shown to reduce invasive fungal infection and its mortality. This study aims to evaluate the effect of fluconazole prophylaxis in VLBW infants on the incidence and mortality of fungal infection. Methods : VLBW infants with endotracheal intubation and central vascular access admitted to the Neonatal Intensive Care Unit (NICU) at Chonnam University Hospital were enrolled. Twenty eight infants of 7-month baseline period from January to July 2005 ('non-fluconazole group') were compared with 29 infants of a 7-month fluconazole period from January to July 2006 ('fluconazole group'). Results : Gestational age, birth weight, sex, mode of delivery, frequency of twin pregnancy, chorioamnionitis, antenatal steroid and rupture of membranes were similar between the fluconazole and non-fluconazole groups. The rate of extremely low birth weight (ELBW) infants, frequency and duration of prophylactic antibiotics, total parenteral nutrition and umbilical catheters, duration of intralipid, mechanical ventilation and nasal continuous positive airway pressure (CPAP) were also not significant. However, frequency of percutaneous central venous catheterization (PCVC) and intralipid administration, and duration of PCVC were significant between the two groups. The overall incidence and mortality of fungal infection were not different between the two groups. Although the Malassezia infection was increased in the fluconazole group (P<0.05), candida was significantly decreased compared to the non-fluconazole group (P<0.05). Conclusion : Fluconazole prophylaxis in high risk VLBW infants decreased the candida infection significantly. Antifungal prophylaxis is recommended in terms of cost effectiveness, but further study is needed to clarify the reason for the increase of Malassezia infection.

• Asia pacific journal of information systems
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• v.17 no.2
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• pp.123-137
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• 2007

The advent of the Internet and related Web technologies has created an easily accessible link between a firm and its customers, and has provided opportunities to a firm to use information technology to support supplementary after-sale services associated with a product or service. It has been widely recognized that supplementary services are an important source of customer value and of competitive advantage as the characteristics of the product itself. Many of these supplementary services are information-based and need not be co-located with the product, so more and more companies are delivering these services electronically. Net-based customer service, which is defined as an Internet-based computerized information system that delivers services to a customer, therefore, is the core infrastructure for supplementary service provision. The importance of net-based customer service in delivering supplementary after-sale services associated with product has been well documented. The strategic advantages of well-implemented net-based customer service are enhanced customer loyalty and higher lock-in of customers, and a resulting reduction in competition and the consequent increase in profits. However, not all customers utilize such net-based customer service. The digital divide is the phenomenon in our society that captures the observation that not all customers have equal access to computers. Socioeconomic factors such as race, gender, and education level are strongly related to Internet accessibility and ability to use. This is due to the differences in the ability to bear the cost of a computer, and the differences in self-efficacy in the use of a technology, among other reasons. This concept, applied to e-commerce, has been called the "e-commerce divide." High Internet penetration is not eradicating the digital divide and e-commerce divide as one would hope. Besides, to accommodate personalized support, a customer must often provide personal information to the firm. This personal information includes not only name and address, but also preferences information and perhaps valuation information. However, many recent studies show that consumers may not be willing to share information about themselves due to concerns about privacy online. Due to the e-commerce divide, and due to privacy and security concerns of the customer for sharing personal information with firms, limited numbers of customers adopt net-based customer service. The limited level of customer adoption of net-based customer service affects the firm profits and the customers' welfare. We use a game-theoretic model in which we model the net-based customer service system as a mechanism to enhance customers' loyalty. We model a market entry scenario where a firm (the incumbent) uses the net-based customer service system in inducing loyalty in its customer base. The firm sells one product through the traditional retailing channels and at a price set for these channels. Another firm (the entrant) enters the market, and having observed the price of the incumbent firm (and after deducing the loyalty levels in the customer base), chooses its price. The profits of the firms and the surplus of the two customers segments (the segment that utilizes net-based customer service and the segment that does not) are analyzed in the Stackelberg leader-follower model of competition between the firms. We find that an increase in adoption of net-based customer service by the customer base is not always desirable for firms. With low effectiveness in enhancing customer loyalty, firms prefer a high level of customer adoption of net-based customer service, because an increase in adoption rate decreases competition and increases profits. A firm in an industry where net-based customer service is highly effective loyalty mechanism, on the other hand, prefers a low level of adoption by customers.

• The Korean Journal of Nuclear Medicine
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• v.26 no.2
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• pp.290-298
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• 1992

Although early diagnosis of urinary tract infection is important, the radiologic evaluation is still controversial because of the low sensitivity and the lack of cost-effectiveness. This study was carried out to evaluate the clinical utility of high resolution triple head $^{99m}Tc-DMSA$ SPECT imaging in urinary tract infection. We prospectively performed $^{99m}Tc-DMSA$ planar and SPECT imaging, ultrasound of kidney (US), intravenous pyelography (IVP) and voiding cystourethrography (VCU) in all 60 adult patients with UTI [26 with first episode of acute pyelonephritis (APN), 22 with recurrent APN, and 12 persistent asymptomatic pyuria] and 25 normal persons. To assess reversibility of the renal cortical defect (RCD), $^{99m}Tc-DMSA$ SPECT was repeated 1 to 8 months later in those patients with abnormal initial findings. Overall detection rate of $^{99m}Tc-DMSA$ SPECT imaging was 83% (50/60), but planar, US, IVP and VCU showed abnormal findings in 68%, 28%, 32% and 13%, respectively. 25 out of 27 patients with normal or single RCD were all normal in other radioligic studies. Only two patients showed vesicoureteral reflux (VUR) on VCU (grade I) and mild hydronephrosis on IVP. But, high proportion of those with multiple RCD showed abnormal findings on US (17/33), IVP (18/33), and VCU (7/33): 67% in any of these 3 studies. Especially, 3 out 7 patients with VUR showed multiple RCD on $^{99m}Tc-DMSA$ SPECT without any abnormality on IVP or US. 25 normal persons showed normal findings in all studies except one false positive finding on $^{99m}Tc-DMSA$ SPECT imaging. Follow-up $^{99m}Tc-DMSA$ SPECT was done in 28 patients (13 with single RCD, 15 with multiple RCD). All 13 patients with single RCD showed improvement. Those with multiple RCD presented improvement in 4, no change in 10, and aggravation in 1 on follow-up studies. With these results, we conclude: 1) $^{99m}Tc-DMSA$ SPECT imaging is superior to planar imaging, US, IVP or VCU in detection of renal lesion in urinary tract infection. $^{99m}Tc-DMSA$ SPECT is useful as a initial diagnostic tool in adult patients with urinary tract infection. 2) The multiple RCD on $^{99m}Tc-DMSA$ SPECT represent the high probability of irreversible tissue change and need of extensive urological work-up.

• Journal of Soil and Groundwater Environment
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• v.12 no.1
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• pp.73-86
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• 2007

Risk-based remediation strategy (RBRS) is a consistent decision-making process for the assessment and response to chemical release based on protecting human health and the environment. The decision-making process described integrates exposure and risk assessment practices with site assessment activities and remedial action selection to ensure that the chosen actions are protective of human health and the environment. The general sequences of events in Tier 1 is as follows: initial site assessment, development of conceptual site model with all exposure pathways, data collection on pollutants and receptors, and identification of risk-based screening level (RBSL). If site conditions do not meet RBSL, it needs further site-specific tier evaluation, Tier 2. In most cases, only limited number of exposure pathways, exposure scenarios, and chemicals of concern are considered the Tier 2 evaluation since many are eliminated from consideration during the Tier 1 evaluation. In spite of uncertainties due to the conservatism applied to risk calculations, limitation in site-specific data collections, and variables affecting the selection of target risk levels and exposure factors, RBRS provides us time- and cost-effectiveness of the remedial action. To ensure reliance of the results, the development team should consider land and resource use, cumulative risks, and additive effects. In addition, it is necessary to develop appropriate site assessment guideline and reliable toxicity assessment method, and to study on site-specific parameters and exposure parameters in Korea.