• Applied Chemistry for Engineering
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• v.26 no.5
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• pp.549-556
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• 2015

Anti-insect repellent silica sol from mixture with silica and anti-insect repellent solution extracted from medicinal herbs was prepared. The micron size porous sphere powder with anti-insect repellent solution was prepared by the spray drying method. The characteristic of anti-insect repellent powder using spray drying method was analyzed by FE-SEM, PSA, TGA with the concentration of anti-insect repellent sol (anti-insect repellent solution and silica) and conditions of spray drier. The average particle size of 4, 7 wt% and 10 wt% of anti-insect repellent sol concentration were 8.3, $9.5{\mu}m$ and $11.7{\mu}m$, respectively. The particle size is increasing with high concentration of anti-insect repellent sol. Other hands, particle size as the temperature of inlet nozzle and velocity of sol injection were nearly same at high velocity of gas injection. Also, Anti-insect repellent impregnation in porous sphere powder were confirmed by TGA methode and its thermal property was stable up to $200^{\circ}C$. We expect that anti-insect repellent powder is applied for plastic compound and process of film manufacture.

• Journal of Food Hygiene and Safety
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• v.37 no.6
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• pp.373-384
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• 2022

Fluoxastrobin a fungicide developed from Strobilurus species mushroom extracts, can be used as an effective pesticide to control fungal diseases. In this study, we optimized the extraction and purification of fluoxastrobin according to its physical and chemical properties using the QuEChERS method and developed an LC-MS/MS-based analysis method. For extraction, we used acetonitrile as the extraction solvent, along with MgSO₄ and PSA. The limit of quantitation of fluoxastrobin was 0.01 mg/kg. We used 0.01, 0.1, and 0.5 mg/kg of five representative agricultural products and treated them with fluoxastrobin. The coefficients of determination (R²) of fluoxastrobin and fluoxastrobin Z isomer were > 0.998. The average recovery rates of fluoxastrobin (n=5) and fluoxastrobin Z isomer were 75.5-100.3% and 75.0-103.9%, respectively. The relative standard deviations (RSDs) were < 5.5% and < 4.3% for fluoxastrobin and fluoxastrobin Z isomer, respectively. We also performed an interlaboratory validation at Gwangju Regional Food and Drug Administration and compared the recovery rates and RSDs obtained for fluoxastrobin and fluoxastrobin Z isomer at the external lab with our results to validate our analysis method. In the external lab, the average recovery rates and RSDs of fluoxastrobin and fluoxastrobin Z isomer at each concentration were 79.5-100.5% and 78.8-104.7% and < 18.1% and < 10.2%, respectively. In all treatment groups, the concentrations were less than those described by the 'Codex Alimentarius Commission' and the 'Standard procedure for preparing test methods for food, etc.'. Therefore, fluoxastrobin is safe for use as a pesticide.

• Korean Journal of Environmental Agriculture
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• v.41 no.2
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• pp.82-94
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• 2022

BACKGROUND: Spiropidion and its metabolite are tetramic acid insecticide and require the establishment of an official analysis method for the safety management because they are newly registered in Korea. Therefore, this study was to determine the analysis method of residual spiropidion and its metabolite for the five representative agricultural products. METHODS AND RESULTS: Three QuEChERS methods (original, AOAC, and EN method) were applied to optimize the extraction method, and the EN method was finally selected by comparing the recovery test and matrix effect results. Various adsorbent agents were applied to establish the clean up method. As a result, the recovery of spiropidion was reduced when using the dispersive-SPE method with MgSO₄, primary secondary amine (PSA), graphitized carbon black (GCB) and octadecyl (C₁₈) in soybean. Color interference was minimized by selecting the case including GCB and C18 in addition to MgSO₄. This method was established as the final analysis method. LC-MS/MS was used for the analysis by considering the selectivity and sensitivity of the target pesticide and the analysis was performed in MRM mode. The results of the recovery test using the established analysis method and inter laboratory validation showed a valid range of 79.4-108.4%, with relative standard deviation and coefficient of variation were less than 7.2% and 14.4%, respectively. CONCLUSION(S): Spiropidion and its metabolite could be analyzed with a modified QuEChERS method, and the established method would be widely available to ensure the safety of residual insecticides in Korea.

• Korean Journal of Environmental Agriculture
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• v.40 no.2
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• pp.108-117
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• 2021

BACKGROUND: Dichlobentiazox is a newly registered pesticide in Korea as a triazole fungicide and requires establishment of an official analysis method for the safety management. Therefore, the aim of this study was to determine the residual analysis method of dichlobentiazox for the five representative agricultural products. METHODS AND RESULTS: Three QuEChERS methods were applied to establish the extraction method, and the EN method was finally selected through the recovery test. In addition, various adsorbent agents were applied to establish the clean-up method. As a result, it was found that the recovery of the tested pesticide was reduced when using the d-SPE method with PSA and GCB, but C₁₈ showed an excellent recovery. Therefore this method was established as the final analysis method. For the analysis, LC-MS/MS was used with consideration of the selectivity and sensitivity of the target pesticide and was operated in MRM mode. The results of the recovery test using the established analysis method and inter laboratory validation showed a valid range of 70-120%, with standard deviation and coefficient of variation of less than 3.0% and 11.6%, respectively. CONCLUSION: Dichlobentiazox could be analyzed with a modified QuEChERS method, and the method determined would be widely available to ensure the safety of residual pesticides in Korea.

• Clinical and Experimental Reproductive Medicine
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• v.21 no.1
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• pp.1-11
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• 1994

The occurrence and time course of capacitation, acrosomal loss, and hyperactivated motility require quantitative definition in order to characterize fertile human sperm. Recently the method has been developed to estimate the quality of spermatozoa by using kinematic parameters such as curvilinear velocity(VCL), average path velocity(VAP), linearity(LIN), straightness(STR), amplitude of lateral head displacement(ALH), and beat cross frequence(BCF) from Computer Assisted Sperm Analysis (CASA). In this study, using the Hamilton Thorn motility analyzer HTM 2030(Hamilton Thorn Research, Beverly, MA), we attempted to identify the spermatozoa with hyperactivated motility (HA) objectively and to monitor hyperactivation of human spermatozoa during incubation in capacitating media and after treatment of calcium ionophore as compared with acrosome status. And we examined whether HA are related to the result of SPA. Semen samples obtained from 16 healthy men were prepared by swim up technique and preincubated in a capacitating media(modified BWW medium) for 5 hours and treated with calcium ionophore solution. The acrosome reaction was detected with PSA-FITC labelling of the acrosome and in vitro sperm ferilizing capacity was assessed by the zona free hamster ovum penetration assay (SPA). The incidence of hyperactivated sperm was 2.6% in fresh semen, 14.3% of the swim up population, 13.7% after 5h of incubation. Significant increase of percentage of hyperactivated sperm was observed after the incubation (p<0.05) but after treatment, no significant changes of percentage of hyperactivated sperm(l1.8%) in contrast to significant rise in the percentage of acrosome reacted cells. Correlation analysis failed to show any significant relationship between the percentage of sperm with HA and SPA score. In conclusion, although no direct correlations were found between the results of SPA and HA, hyperactivation of sperm is associated with capacitation and monitoring hyperactivated sperm will be expected as a method of evaluating the functional quality of sperm such as SPA.

• Clean Technology
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• v.23 no.2
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• pp.181-187
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• 2017

The perfluorocompounds (PFCs) emitted from the semiconductor and display manufacture is treated by abatement systems which use various technologies, such as combustion, thermal, plasma, catalyst. However, it is required that the system should overcome their drawbacks with excess energy consumption and low removal efficiency. The new technology using combination of pressure swing adsorption and excess enthalpy combustion for the reduction of PFCs emissions were developed and analyzed its characteristics. PFCs concentration ratio and PFCs loss factor were calculated from measuring concentration of PFCs at the calculated by comparing concentration of PFCs at the combustor's inlet and outlet. There were performance evaluations with various gas flow for comparing energy consumption and removal efficiency with existing equipments. The concentration ratio and the loss factor of PFCs were 1.65, 8.2%, respectively, when the total gas flow of the pressure swing absorption (PSA) inlet was 204 liter per minute (LPM) and $CF_4$ concentration was 1412 ppm. In comparison with existing system at constant condition, $CF_4$ removal efficiency for a porous media combustion (PMC) showed the improvement more than 16% and the consumed energy was also reduced up to approximately 41%. Then, the total gas flow introduced into PMC and $CF_4$ concentration were 91-LPM and 2335 ppm, respectively, and the destruction and removal efficiency of $CF_4$ was about 96% at 19-LPM $CH_4$, and 40-LPM $O_2$.

• Journal of Food Hygiene and Safety
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• v.38 no.3
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• pp.79-88
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• 2023

Trifludimoxazin is a triazinone herbicide that inhibits the synthesis of protoporphyrinogen oxidase (PPO). The lack of PPO damages the cell membranes, leading to plant cell death. An official analytical method for the safety management of trifludimoxazin is necessary because it is a newly registered herbicide in Korea. Therefore, this study aimed to develop a residual analysis method to detect trifludimoxazin in five representative agricultural products. The EN method was established as the final extraction method by comparing the recovery test and matrix effect with those of the QuEChERS method. Various sorbent agents were used to establish the clean-up method, and no differences were observed among them. MgSO₄ and PSA were selected as the final clean-up conditions. We used LC-MS/MS considering the selectivity and sensitivity of the target pesticide and analyzed the samples in the MRM mode. The recovery test results using the established analysis method and inter-laboratory validation showed a valid range of 73.5-100.7%, with a relative standard deviation and coefficient of variation less than 12.6% and 14.5%, respectively. Therefore, the presence of trifludimoxazin can be analyzed using a modified QuEChERS method, which is widely available in Korea to ensure the safety of residual insecticides.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.365-376
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• 2020

Immature embryogenesis is a useful process in wheat tissue culture, including transgenic technology, because of its high regeneration efficiency compared to that in other tissues. However, it is a very labor-intensive and time-restrictive method, because the preparation of immature embryos is limited to the optimal time after flowering. In this experiment, 'Speed Breeding', a breeding technique that accelerates breeding generation advancement by extending the photoperiod, was applied to the wheat variety 'Bobwhite'. A controlled growth room was constructed by adjusting the photoperiod (22-hour light/2-hour dark) using LED lights at temperature of 22℃. After vernalization of the Bobwhite seeds at 4℃ for 4 weeks, the seedlings were grown in a controlled growth room and a greenhouse to compare the heading date. In both conditions, calli were induced from immature embryos on the 11^th day after flowering. After 4 weeks, the calli were transferred to a regeneration medium. Regeneration efficiencies under greenhouse conditions and Speed Breeding conditions were determined as 45.05% and 43.18%, respectively. Antioxidant enzyme activity and reference gene expression analysis were performed to confirm the presence of stress due to an extremely long-day photoperiod. As a result, the antioxidant enzyme activity was not distinguished from that of the greenhouse condition. The reference gene expression analysis revealed that the PsaA and CDC genes were highly expressed under the Speed Breeding condition. However, expression of PsbA was similar expression in both conditions. These results will provide useful information for the application of immature embryogenesis to the wheat transformation system.

• Journal of Embryo Transfer
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• v.33 no.3
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• pp.185-194
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• 2018

The aim of this study was performed to evaluate the effects of ice-binding protein from the arctic yeast Leucosporidium (LeIBP) supplementation on cryopreservation of boar sperm. The collected semen was diluted ($1.5{\times}10^8/ml$) in lactose egg yolk (LEY) and cooled at $5^{\circ}C$ for 3 h. The cooled semen was then diluted ($1{\times}10^8/ml$) in LeIBP containing LEY with 9% glycerol and maintained at $5^{\circ}C$ for 30 min. The semen was divided into six experimental groups (control, 0.001, 0.005, 0.01, 0.05 and 0.1 mg/ml of LeIBP). The straws were kept on above the liquid nitrogen ($LN_2$) vapors for 20 minutes and then plunged into $LN_2$. After thawing, computer-assisted sperm analysis was used for sperm motility and flow cytometry was performed to assess the viability, acrosome integrity (FITC-PSA/PI), ROS (DCF/PI), lipid peroxidation (BODIPY C11/PI) and apoptosis (Annexin V/PI), respectively. No significant responses were observed for sperm motility. However, sperm viability was significantly increased on 0.05 and 0.1 mg/ml of LeIBP groups compared to control (P < 0.05). In addition, acrosome integrity was significantly increases LeIBP groups (P < 0.05) and both ROS and lipid peroxidation level were lower in all LeIBP groups than those of control (P < 0.05). On the other hand, a significant higher apoptosis rate was observed in 0.05 and 0.1 mg/ml of LeIBP groups compared to control (P < 0.05). It can be assumed that a supplementation of LeIBP in boar sperm freezing extender is an effective method to increase the sperm qualities after cryopreservation.

• Polymer(Korea)
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• v.36 no.3
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• pp.344-350
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• 2012

New pressure sensitive adhesives (PSAs) for polarizer film were prepared by electron beam (e-beam) radiation to acrylic copolymers, and their adhesive properties were investigated. The acrylic copolymers were synthesized by free radical polymerization of $n$-butylacrylate (BA), 2-hydroxyethyl methacrylate (HEMA), and acrylic acid (AA). The acrylic copolymers were coated on PET release films to a thickness of 25 ${\mu}m$, laminated to polarizer films, and then radiated with e-beam at room temperature. Gel fractions of all the acrylic copolymers after e-beam radiation at 50 kGy were higher than 93%, and their crosslinking densities were increased with increasing the content of HEMA units. PSA prepared by e-beam radiation of acrylic copolymer synthesized with a feed ratio of BA/HEMA/AA = 89.5/10/0.5 (w/w/w) at a dose of 50 kGy exhibited the best adhesion performances in terms of peel strength, creep resistance, durability and reliability, and light leakage. It is expected that the preparation method of PSAs via e-beam irradiation will improve the producibility and workability of polarizer film for liquid crystal display.