• Korean journal of applied entomology
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• v.52 no.4
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• pp.357-364
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• 2013

Bee-vectoring is a new crop protection technology used for suppressing insect pests and diseases in crops by disseminating microbial agents into plants during bee pollination activities. In this study, we conducted bee-vectoring trials in cherry tomato greenhouses by using the bumble bee (Bombus terrestris), a microbial agent (Bacillus subtilis) and a new dispenser, and we measured the delivered quantity of microbial agent. Bacterial colony forming units (CFUs) in bees exiting a dispenser ranged from $9.0{\times}10^5$ to $1.9{\times}10^6$ per bee. At greenhouse trials in the National Academy of Agricultural Science (NAAS) trials, 3,300 - 8,500 CFUs per flower were counted and 80 - 100% of the flower samples contained detectable concentrations. There was no significant difference in CFU density between microbial replacement intervals (once a week vs twice a week) in the NAAS trials. In a commercial greenhouse trial, 1,800 - 2,400 CFUs per flower were found, and 83 - 93% of the flower samples contained detectable concentrations. CFUs detected in bee-vectored flowers increased by approximately 75 times before bee-vectoring. The mortality of bumble bees in the NAAS trials was, on average, 22% and little negative effects were observed on the bumble bee colonies. The yield difference for cherry tomatoes in the NAAS trials was not significant between treatments. When we select additional microbial agents that can be disseminated using this technology and create a detailed plan based on insect pests and disease incidence, we can apply this technology in greenhouses for growing tomatoes and strawberries in the near future.

• Korean journal of applied entomology
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• v.57 no.3
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• pp.209-220
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• 2018

Mating disruption (MD) has been widely used to effectively control Grapholita molesta in apple orchards. A simultaneous mating disruption (SMD) techniques have been developed to control both G. molesta and G. dimorpha. This study was performed to determine the practical parameters to apply the SMD technique to field conditions. To determine the application amount of SMD lures, a dispenser containing 10 mg pheromone was placed at different numbers of trees in an orchard. Application at every other tree (= one dispenser per two trees) was relatively safe to expect effective MD efficiency in both wax and polyethylene (PE) formulations. One time application at the end of March was enough to maintain a year round MD efficacy against both species. A fence treatment using food trap was applied to prevent any immigratory mated females from nearby untreated regions. To enhance the food trap by adding host-derived secondary compounds, terpinyl acetate (TA) was screened to be effective to attract females of Grapholita molesta among six compounds contained in apple fruit extracts. Among different TA concentrations, 0.05% TA treatment was the most effective to attract the adults. A mixture of TA and sugar was effective to attract and kill females and called FAKT (female attract-to-kill techniques). FAKT was treated at approximately 6 m interval at the edge of the apple orchards. The females trapped by the FAKT included mated females possessing vitellogenic oocytes. SMD supplemented with FAKT maintained the high MD efficacy and significantly suppressed leaf damage induced by the two insect pests compared to control or single SMD treatment.

• Journal of Periodontal and Implant Science
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• v.29 no.1
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• pp.141-151
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• 1999

To evaluate the effect of cetylpyridinium chloride in a powder form when used concomitantly with a commercial flouride containing tooth paste on inhibition of plaque formation, on gingivitis, and on irritation of oral mucosa, a double--blind, randomized parallel study was set up. Cetylpyridinium chloride was incorporated into a ligh brown colored powder with menthol added for scent. There were no diffemces between the active agent and the placebo which did not contain cetylpyridinium chloride in appearance, color, smell, taste, or dispenser. 98 healthy volunteers were assigned to one of two groups: brushing 3 times a day with flouride toothpaste and cetylpyridinium chloride powder, or brushing 3 times a day with flouride toothpaste and placebo. Before the test period, the subjects received through tooth cleaning and polishing. At basteline, GI, PI, BOP, and GCF of the Ramfjord teeth were measured in the experimental and placebo groups including 58 and 42 subjects repectively, After 4 weeks, GI, PI, BOP, GCF, compliance, irritation of the oral mucosa(redness, pus drainage, edema) and adverse reactions were measured. The PI, GI, and BOP of the experimental group recorded at baseline are 0.19${\pm}$0.19, 0.42${\pm}$0.31, and 0.08${\pm}$0.15. These scores showed significant decrease after 4 weeks of test period(0.11${\pm}$0.15, 0.22${\pm}$0.24, 0.02${\pm}$0.09 repectively at the end of the study) and inhibition of plaque accumulation and resolution of gingival inflammation could be observed. GCF shoed slight increase but this was not statistically different. Comparison of changes in measured scores of control and experimental groupshow GI, PI of the test indices have decreased. Test group showed significantly greater decrease in gingivitis and plaque accumulation after 4 weeks. GCF and BOP also showed greater decrease thant the control group but this difference was not statistically significant. At no time of the study period did any of the subjects show signs of irritation of the oral mucosa or adverse reactions. Following conclusions could be obtained from this study. The combined use of cetl powder and flouride toothpaste showed greater inhibition of plaque accumulation and greater decrease of gingivitis than use of flouride toothpaste with placebo agent.

• Korean journal of applied entomology
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• v.56 no.1
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• pp.51-60
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• 2017

The striped fruit fly, Bactrocera scutellata, infests pumpkin flowers. Males are attracted to raspberry ketone (RK) and feed the attractant. This study was conducted to determine essential techniques to develop a male annihilation technique (MAT) of this insect pest. Effective attractants were screened in laboratory and field conditions. Both males and females were responsive to methyl eugenol (ME) in laboratory, though no flies were attracted to ME traps in field conditions. In contrast, cuelure (CL), which is a chemical derivative of RK, was effective to attract males of B. scutellata in both laboratory and field conditions. However, RK was equivalent or superior to CL when they were formulated in a form of wax dispenser. A pyrethroid insecticide along with the attractant was effective to attract and kill B. scutellata. Funnel trap was useful for MAT to confirm and count dead flies. These results indicate that MAT against B. scutellata consists of RK and bifenthrin in a wax type formulation, which is installed to a funnel type of trap. These essential factors would be useful to develop MAT applicable to control B. scutellata in fields.

• Journal of the Korean Dietetic Association
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• v.4 no.2
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• pp.235-244
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• 1998

Hand washing is an important component of hygiene program for food handlers. Hands can be a source of direct or indirect contamination of foods with pathogenic microorganisms. In this study, the effectiveness of hand washing methods and the use of 70% alcohol solution against transient skin bacteria was tested in an university foodservice facility. 70% alcohol solution is sprayed for 5 seconds automatically when hands are placed in the dispenser. Samples were taken using swab technique in meat cutting area, vegetable trimming area, and vegetable cutting area: before and after washing hands according to planned methods, and after being sprayed with 70% alcohol solution after washing hands. The bacteriological analysis of total plate counts, coliform, fecal coliform of food handlers' hands was done. Statistical data analysis was completed with Mann-Whitney U test and Kruskal-Wallis model using the SPSS program. The levels of initial contamination of workers' hand were significantly different by the work areas($x^2$=9.156, p<0.01). Workers in the vegetable trimming area had more heavily soiled hands than in the other work areas. Mean of TPC counts and coliform was 8.97×$10^5$ CFU/12.4$cm^2$, 2.93×$10^2$ MPN/12.4$cm^2$ respectively, but fecal coliform was not detected. Transient bacteria were removed from hands after washing and using 70% alcohol solution but were not removed completely. Mean reduction percentage in TPC varied among work areas and ranged from 93.19% to 94.99%, and in coliforms from 97.31% to 100%. A significant difference in TPC was found between before and after hand disinfection (Z=-2.714, p<.01) and between standardized hand washing procedures and un-standardized hand washing procedures(z=-2.301, p<.01). Subjects using the hand sanitizer showed a great elimination of TPC(99.45% reduction), but this effect was valid only after following proper washing procedures. Based on the results, the most effective hand washing method was recommended as the combination of the standardized hand washing procedure with warm-water and use of the 70% alcohol solution. The results can be used to develop hand hygiene programs and training strategies for enhancing hand hygiene practices for food handlers in foodservice operations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.6925-6931
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• 2015

LED(Light Emitting Diode) is used in various filed like a display because of low power consuming, long life span, high brightness, rapid response time and environmental-friendly characteristic. General fabrication method is combination blue light LED chip with yellow fluorescent substance. Because this way is suitable for industry field in terms of convenience, economic, efficiency. In white light LED packaging process, encapsulation process that is dispensing fluorescent substance with silicon to blue light LED chip is most important. So, in this paper we develop EHD pump system using voice coil motor and electrostatic pump for dispensing fluorescent substance. For these things we conduct basic test about liquid surface profiles by voltage and process time. Through this data we decide optimal process condition and verify the optimal condition using design of experiment method. And to confirm uniformity of the condition, we conduct repeat dispensing test.

• Journal of Environmental Health Sciences
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• v.45 no.5
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• pp.434-442
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• 2019

Objectives: This study was performed in order to report the epidemiological features of a food poisoning outbreak caused by multiple pathogens in a high school in Chungcheongnam-do Province, Korea in April 2019 and to suggest measures to prevent a similar incidence. Methods: A total of 39 patients with diarrhea were examined. Environmental samples were obtained from 6 food handlers, 4 food utensils, 72 preserved foods served during the food poisoning outbreak, 9 door handles, 10 drinking water samples from water dispensers, and 6 ground water samples from water taps. These analyzed to detect viruses and bacteria. Results: Among the 39 patients, 21 cases (53.8%) of enteroaggregative E. coli (EAEC), 7 cases of Staphylococcus aureus (17.9%), and 17 cases of norovirus (43.6%) were positive, and in 16 of the cases a co-infection with at least one other pathogen were observed. EAEC was assumed to be transmitted from contaminated drinking water because it was also detected in the water sample from a water dispenser in the dormitory. Staphylococcus aureus was isolated only in the fecal samples of patients, meaning it was not possible to trace its origin. The genotype of norovirus detected in the drinking water and ground water was consistent with that isolated from patients, and it was determined that the norovirus infection originated from the school's water environment. Conclusions: These findings indicate that a lack of environmental hygiene management related to school meals caused the food poisoning incident. In particular, a lack of management of drinking water, water supply, and personal hygiene should be pointed out. This should be urgently addressed and continuous monitoring should be carried out in the future. In addition, students and staff should be educated and trained to improve their personal hygiene.

• Journal of Dental Rehabilitation and Applied Science
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• v.35 no.1
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• pp.27-36
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• 2019

Purpose: The aims of this study were to evaluate the dentist's awareness and the actual status of infection control of noncritical dental instruments. Materials and Methods: 40 dental clinics in Daejeon, South Chungcheong, North Chungcheong and North Jeolla provinces were surveyed. The questionnaire was delivered to the dentists belonging to those clinics, and the awareness and the practice of infection control were examined. The microbial contamination on the surface of five noncritical instruments (impression gun, light curing unit, 3-way syringe, shade guide, and dental floss dispenser) used by them was measured with an ATP luminometer. Correlation analysis between the awareness and the actual state of infection control was conducted. Results: Awareness and frequency of infection control was highest in the 3-way syringe. Surface disinfection using disinfectant was most frequent in all instruments. 3-way syringes and shade guides were less contaminated than impression guns, light curing units, and dental floss dispensers. Conclusion: 3-way syringes had a significant correlation between user awareness of infection control and surface contamination, and the higher awareness, the lower the contamination measurement was shown.

• Korean Journal of Materials Research
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• v.29 no.11
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• pp.720-726
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• 2019

Recently, research on cost reduction and efficiency improvement of crystalline silicon(c-Si) photovoltaic(PV) module has been conducted. In order to reduce costs, the thickness of solar cell wafers is becoming thinner. If the thickness of the wafer is reduced, cracking of wafer may occur in high temperature processes during the c-Si PV module manufacturing process. To solve this problem, a low temperature process has been proposed. Conductive paste(CP) is used for low temperature processing; it contains Sn57.6Bi0.4Ag component and can be electrically combined with solar cells and ribbons at a melting point of $150^{\circ}C$. Use of CP in the PV module manufacturing process can minimize cracks of solar cells. When CP is applied to solar cells, the output varies with the amount of CP, and so the optimum amount of CP must be found. In this paper, in order to find the optimal CP application amount, we manufactured several c-Si PV modules with different CP amounts. The amount control of CP is fixed at air pressure (500 kPa) and nozzle diameter 22G(outer diameter 0.72Ø, inner 0.42Ø) of dispenser; only speed is controlled. The c-Si PV module output is measured to analyze the difference according to the amount of CP and analyzed by optical microscope and Alpha-step. As the result, the optimum amount of CP is 0.452 ~ 0.544 g on solar cells.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.300-307
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• 2022

Time-resolved serial femtosecond crystallography (TR-SFX) is a powerful technique for determining temporal variations in the structural properties of biomacromolecules on ultra-short time scales without causing structure damage by employing femtosecond X-ray laser pulses generated by an X-ray free electron laser (XFEL). The mixing rate of reactants and biomolecule samples, as well as the hit rate between crystal samples and x-ray pulses, are critical factors determining TR-SFX performance, such as accurate image acquisition and efficient sample consumption. We here develop two distinct sample delivery systems that enable ultra-fast mixing and on-demand droplet injecting via pneumatic application with a square pulse signal. The first strategy relies on inertial mixing, which is caused by the high-speed collision and subsequent coalescence of droplets ejected through a double nozzle, while the second relies on on-demand pneumatic jetting embedded with a 3D-printed micromixer. First, the colliding behaviors of the droplets ejected through the double nozzle, as well as the inertial mixing within the coalesced droplets, are investigated experimentally and numerically. The mixing performance of the pneumatic jetting system with an integrated micromixer is then evaluated by using similar approaches. The sample delivery system devised in this work is very valuable for three-dimensional biomolecular structure analysis, which is critical for elucidating the mechanisms by which certain proteins cause disease, as well as searching for antibody drugs and new drug candidates.