Current status and management of fluvalinate resistance of Varroa mites in Korea

Susie Cho,Joonhee Lee,Youngcheon Lim,Jonghyeok Lee1,Si Hyeock Lee 한국응용곤충학회 2023 한국응용곤충학회 학술대회논문집 Vol.2023 No.10

The Varroa mite, Varroa destructor is an ectoparasite that parasitizes honey bees. The widespread usage of acaricides, particularly fluvalinate, has resulted in the emergence of resistance in Varroa mite populations all over the world. The goal of this study is to track fluvalinate resistance in Varroa mite field populations in Korea using both bioassay and molecular markers. To accomplish this, a residual contact vial (RCV) bioassay for on-site resistance monitoring was developed. Early mortality evaluation in the RCV bioassay was effective for reliably separating mites with the knockdown resistance (kdr) genotype, but late mortality evaluation was useful for distinguishing mites with additional resistance factors. The RCV bioassay of 14 field mite populations collected in 2021 revealed potential resistance development in four populations. Quantitative sequencing was used as an alternate method to examine the frequency of the L925I/M mutation in the voltage-gated sodium channel (vgsc), which is related with the fluvalinate kdr phenotype. While the mutation was not present in Varroa mite populations in 2020, it appeared in 2021, rose in frequency in 2022, and was practically ubiquitous across the country by 2023. This recent emergence and rapid spread of fluvalinate resistance within a span of three years demonstrate the Varroa mite's significant potential for developing resistance. This situation emphasizes the critical necessity to replace fluvalinate with alternate acaricides, such as fenpyroximate, coumaphos, and amitraz. A few novel vgsc mutations potentially involved in resistance were identified. Potential factors driving the rapid expansion of resistance were further discussed.

Development of an infant formula certified reference material for the analysis of organic nutrients

Lee, Joonhee,Kim, Byungjoo,Lee, Sun Young,Choi, Jongoh,Kang, Dukjin,Lee, Hwasim,Choi, KiHwan,Lee, Hyeyoung,Sim, Hee-Jung,Baek, Song-Yee,Lee, Honghee,Hyung, Seok-Won,Ahn, Seonghee,Seo, Dongwon,Hwang, J Applied Science Publishers 2019 Food chemistry Vol.298 No.-

<P><B>Abstract</B></P> <P>Infant formula certified reference material (CRM, KRISS CRM 108-02-003) were developed for the analysis of organic nutrients. The CRM is a milk-based infant formula powder, packaged at 14 g per unit. Ten thousand units were prepared and stored at −70 °C. For the certification of each nutrient, ten units were analyzed for simultaneous value-assignment and homogeneity test. Analytical methods used were isotope dilution mass spectrometry (IDMS) based on liquid chromatography mass spectrometer (LC/MS) or gas chromatography mass spectrometer (GC/MS) as higher-order reference methods.13 vitamins, 3 fatty acids, and total cholesterol were certified. The between-unit relative standard deviation of measurement results for each nutrient ranged 0.2% to 2.5%, showing very good homogeneity. The expanded relative uncertainties of the certified values ranged from 1% to 8%, indicating that they have higher-order metrological quality. The values of proximates (proteins, lipids, carbohydrates, water, and ash) were assigned through inter-laboratory comparisons.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An infant formula CRMs for the analysis of organic nutrients was developed. </LI> <LI> Organic nutrients were certified by IDMS approaches as higher-order reference methods. </LI> <LI> Homogeneities and stability of the CRM were evaluated by IDMS approaches. </LI> <LI> Metrological qualities of the certified values were proved by their small uncertainties. </LI> <LI> Five proximates were value-assigned by interlaboratory comparison. </LI> </UL> </P>

Fate of Nitrogen Deriving from Treated Pig Slurry in Paddy Soil-Plant Continuum

Joonhee Lee(이준희),Honglim Choi(최홍림) 한국토양비료학회 2015 한국토양비료학회 학술발표회 초록집 Vol.2015 No.5

Mass Balance Method for Purity Assessment of Organic Reference Materials: for Thermolabile Materials with LC-UV Method

Lee, Joonhee,Kim, Byungjoo Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.11

A mass balance method for purity assessment of thermolabile organic reference materials was established by combining several techniques, including liquid chromatography with UV/VIS detector (LC-UV), Karl-Fischer (K-F) Coulometry, and thermal gravimetric analysis (TGA). This method was applied to three fluoroquinolones like enrofloxacin, norfloxacin and ciprofloxacin. LC-UV was used to analyze structurally related organic impurities based on UV/VIS absorbance spectra obtained in combination with LC separation. For all three organic reference materials, the UV/VIS spectra of the separated impurities were similar to that of the major component of the corresponding materials. This indicates that the impurities are structurally related to the respective reference material sharing common chromophores. Impurities could be quantified by comparing their absorbances at the wavelength of maximum absorbance (${\lambda}_{max}$). The water contents of the reference materials were measured by K-F Coulometry by an oven-drying method. The total inorganic impurities contents were assayed from ash residues in TGA analysis with using air as a reagent gas. The final purities estimated from results of those analytical techniques were assigned as ($99.91{\pm}0.06$), ($97.09{\pm}0.17$) and ($91.85{\pm}0.17$)% (kg/kg) for enrofloxacin, norfloxacin and ciprofloxacin, respectively. The assigned final purities would be applied to the reference materials which will be used as calibrators for the certification of those compounds in matrix CRMs as starting points for the traceability of their certified values to SI units.

Sliding mode observer for exhaust pressure estimation in light-duty diesel engines equipped with VGT and EGR system

Joonhee Lee,Hyunjun Lee,Minkwang Lee,Myoungho Sunwoo 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11

This paper proposes a nonlinear sliding mode observer for exhaust pressure estimation. A precise estimation of the exhaust pressure is important for the control of a variable geometry turbocharger (VGT) and exhaust gas recirculation (EGR) system. In order to estimate the exhaust pressure accurately, we derive nonlinear dynamic models of the intake and exhaust pressure in diesel engines based on the energy and mass conservation laws. The model parameters which vary with the engine operating conditions are modeled through an empirical approach to consider physical phenomenon of each component. We develop the nonlinear sliding mode observer for the exhaust pressure estimation to deal with nonlinear dynamics of the diesel engine air system. The stability of the proposed observer is guaranteed by the Lyapunov stability criterion. Moreover, the estimation performance is improved by adding a damping term into the observer. The proposed observer is implemented in a real-time embedded system and the experimental results represent that the observer estimates exhaust pressure precisely in both steady and transient engine operating conditions.

GaN Surface-Emitting Laser With Monolithic Cavity-Folding Mirrors

Lee, Jae-Soong,Lee, Joonhee,Jeon, Heonsu IEEE 2007 IEEE photonics technology letters Vol.19 No.5-8

<P>We report on the demonstration of a GaN-based surface-emitting laser (SEL) in a folded-cavity (FC) scheme. Two 45deg-angled sidewall deflectors were monolithically integrated at both the edges of an otherwise conventional InGaN multiple-quantum-well edge-emitting laser structure. Despite a low effective mirror reflectivity of R(<1%), the optically pumped broad-area laser structure produced laser oscillation in the vertical direction with a low threshold pump intensity of ~350kW/cm<SUP>2</SUP>. Computer simulations on the FC, which was based on the finite-difference time-domain method, not only quantified the cavity quality of our FC-SEL device but also suggested methods to lower the laser threshold</P>

Adhesion of CD40-stimulated Germinal Center B Cells to HK Cells Employs the CD11a/CD18-CD54 Interactions

Lee, Joonhee,Choe, Jongseon The Korean Association of Immunobiologists 2003 Immune Network Vol.3 No.3

Background: The molecular basis of follicular dendritic cells (FDC)-germinal center (GC) B cell interaction is largely unknown, although this cellular interaction is thought to be important for the whole process of GC B cell differentiation. Methods: Using FDC-like cells, HK, and highly purified GC B cells, we attempted to identify the molecules that play critical roles in the interactions between FDC and B cells. GC B cells were co-cultured with HK cells and soluble CD154 in the presence or absence of various function-blocking monoclonal antibodies to examine their effect on GC B cell binding to HK cells and B cell proliferation. Results: Anti-CD11a and anti-CD54 antibodies inhibited GC B cell binding to HK cells while anti-CD49d and anti-CD106 antibodies did not. GC B cell proliferation was not impaired by the disruption of GC B cell-HK cell adherence. Conclusion: Our results suggest that CD11a/CD18-CD54 interactions play an important roles in the initial binding of GC B cells to FDC and diffusible growth factors from FDC may be responsible the massive proliferation of GC B cells.

Perception and Actual Experiences of Sexual Harassment in Clinical Placement among Physical Therapy College Students

( Joonhee Lee ) 대한물리치료학회 2020 대한물리치료학회지 Vol.32 No.1

Purpose: This study examined the level of self-esteem and awareness of sexual harassment among college students majoring in physical therapy to discover the status of sexual harassment and the types of and responses to sexual harassment at clinical training sites. Methods: The study participants included 195 college students majoring in physical therapy in Gyeonggi and Chungcheong provinces, who responded fully to the survey questionnaire. The data were prepared through self-reporting on a structured questionnaire and collected from September to November 2018. Results: The difference in the mean value of self-esteem was evident between the two groups investigated. The most common types of sexual harassment were verbal, visual, and physical. The types of damage reported by the participants were emotional, physical, and social. The group of participants who experienced sexual harassment had a high rate of avoidance, while the group of participants who did not experience sexual harassment exhibited a high rate of coping. Conclusion: The incidence of verbal sexual harassment was reported to be significantly higher, and the emotional damage was the most serious. Students should be provided with more specific and realistic preventive education or countermeasures so they can respond more proactively to real situations.

Polarization-dependent GaN surface grating reflector for short wavelength applications

Lee, Joonhee,Ahn, Sungmo,Chang, Hojun,Kim, Jaehoon,Park, Yeonsang,Jeon, Heonsu The Optical Society 2009 Optics express Vol.17 No.25

<P>This study proposes a one-dimensional sub-wavelength grating structure on GaN surface which behaves as a reflector for transverse-electric polarized light in the blue wavelength range. The rigorous coupled-wave analysis method was used to analyze the effects of various structural parameters on the reflectance spectra of the grating. Based on the optimal design, a GaN surface grating reflector (SGR) was fabricated using holographic lithography and dry etching processes. It showed reflectance that exceeded 90% over a 60-nm bandwidth. The obtained experimental results were in good agreement with simulated ones. The SGR has an advantage of structural simplicity, which should greatly facilitate the fabrication and integration of high reflectors on GaN-based short-wavelength photonic devices.</P>

Development of Certified Reference Materials for Organic Nutrients

Joonhee Lee 한국분석과학회 2019 학술대회논문집 Vol.2019 No.11