Panonychus citri Can Induce T-helper Type 2 Immune Responses via the Release of Thymic Stromal Lymphopoietin and IL-4

Jaechun Lee,Seong-Chul Hong,Young-Bae Chung,Hye-Sook Lee,Keun Hwa Lee 대한바이러스학회 2014 Journal of Bacteriology and Virology Vol.44 No.4

A Basic Concept of Asthma

Jaechun Lee 한국식품영양과학회 2022 한국식품영양과학회 학술대회발표집 Vol.2022 No.10

Sputum Induction with Hypertonic Saline Has No Benefits over Self-expectorated Sputum in the Bacteriologic Confirmation of Pulmonary Tuberculosis

( Jaechun Lee ),( Gil Myeong Seong ),( Su Hee Kim ),( Jong Hoo Lee ),( Miok Kim ) 대한결핵 및 호흡기학회 2012 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.114 No.-

Backgrounds: The bacteriologic diagnosis in pulmonary tuberculosis is confirmative, even though successful rates in self-ex-pectorated sputum are limited. In the previous studies, sputum specimens induced by hypertonic saline nebulization facilitated bacteriologic diagnosis with higher sensitivity over those from self-expectorated sputum. The benefits of the sputum induction were investigated in the diagnosis of pulmonary tuberculosis. Methods: A prospective randomized case-control study in one hospital. The subjects highly suspicious of pulmonary tuber-culosis were asked to provide 3 pairs of sputum specimens in 3 consecutive days. The first pairs of the specimens were obtained either by self-expectoration (SE) from the next day of the visit or sputum induction with 7% saline nebulization at presentation (HS) and the other pairs were collected in the same ways. The samples were used for acid fast bacilli staining, mycobacterial culture and PCR. The outcomes of bacteriologic detections were compared. Results: Seventy one patients were assigned either into SE (35 subjects, age of 52±17, 69% male) and HS (36, 54±17, 47%). Forty one subjects with pulmonary tuberculosis (57.7%) and 3 with non-tuberculous mycobacterial infection (4.2%) were diagnosed. At presentation, 21 (60%) of SE and 20 (55.6%) of HS revealed scanty amounts of sputum (p=0.705). In the myco-bacterial detection, HS (13 subjects, 36.1%) and SE (13, 37.1%) showed no difference (p=0.928). Consequently, 22 (62.9%) of SE and 19 (52.8%) of HS were clinically diagnosed and treated as pulmonary tuberculosis.

High-Q active resonators using amplifiers and their applications to low phase-noise free-running and voltage-controlled oscillators

Lee, Young-Taek,Lee, Jaechun,Nam, Sangwook Professional Technical Group on Microwace Theory a 2004 IEEE transactions on microwave theory and techniqu Vol.52 No.11

This paper presents a new technique to design high-Q active resonators. The active resonators are then used in the design of low phase-noise oscillators. The proposed new technique uses an amplifier to generate a negative resistance, which compensates for the resonator losses and increases the Q factor. The active resonator using this technique shows a high loaded Q factor of 548.62 from measurement at the fixed 10-GHz resonant frequency. Considerations to design a voltage tunable active resonator is given and measurements show that the loaded Q factors exceed 500 with a 120-MHz tuning range. A low phase-noise free-running and voltage-controlled oscillator (VCO) were designed as an application of the proposed active resonators. The phase noise of the free-running oscillator using the active resonator is -114.36 dBc/Hz at 100-kHz offset, which is 14 dB lower than the phase noise of the passive resonator oscillator. In the case of a VCO using the active resonator, the phase-noise performance is below -110 dBc/Hz over the whole tuning range, which is lower 13 dB compared to the passive resonator VCO. The total dc power consumptions are approximately 500 mW.

Effective Area of a Receiving Antenna in a Lossy Medium

Jaechun Lee,Sangwook Nam IEEE 2009 IEEE transactions on antennas and propagation Vol.57 No.6

<P>The effective area for a receiving antenna in a lossy medium is derived by solving a receiving problem of an insulated Hertzian dipole with its gain obtained beforehand. As a result, the effective area in a general medium is found to be the product of the gain and pi/Re[omegaradic{epsivmu*}]<SUP>2</SUP> . The latter term becomes same as the previous formula, pi/Re[omegaradic{epsivmu}]<SUP>2</SUP>=4pi/lambda<SUP>2</SUP> when the medium is only electrically or magnetically lossy. A simulation result of power transmission between two insulated small dipoles validates the theory.</P>

Fundamental Aspects of Near-Field Coupling Small Antennas for Wireless Power Transfer

Jaechun Lee,Sangwook Nam IEEE 2010 IEEE transactions on antennas and propagation Vol.58 No.11

<P>A physical limitation on the power transfer efficiency between two electrically small antennas in the near-field range is presented. By using a Z-parameter which describes the interaction between two antennas for spherical modes in connection with antenna parameters, the maximum power transfer efficiency and the optimum load impedance are shown as functions of the distance between two antennas, the radiation efficiency and the input impedance of the isolated antenna. The theory is verified by a simulation with a small helical antenna, which generates and modes, simultaneously.</P>

다양한 하중조건을 고려한 엔진밸브시트의 변형 및 마모 해석 기초 연구

고재천(JaeChun Ko),방인완(InHwan Bang),차상우(SangWoo Cha),이경우(KyungWoo Lee),신성원(SungWon Shin),윤재현(Jae Hyun Yun),이종수(JongSoo Lee) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.5-2

엔진은 구동시 높은 열과 다양한 하중으로 인해 변형이 생기게 된다. 특히 밸브와 밸브시트 사이에서 다양한 하중의 영향으로 마모가 발생하게 된다. 현재까지 밸브를 포함한 엔진의 내구해석은 개발이 미흡했다. 본 연구는 밸브를 포함한 엔진의 내구해석을 통해 밸브시트 마모에 영향을 주는 인자를 찾아내는 것이다. 유한 요소 해석은 Hypermesh와 ABAQUS에 의해 수행되었다. 이번 연구에서 고려된 하중조건은 볼트 체결력, 열하중, 연소압, Max Valve Closing Force 등이다. 해석 모델은 많은 하중조건과 접촉 조건을 고려하여 보다 실제 모델과 가깝게 만들려 하였다. 마모에 대한 평가는 Archards’s equation을 바탕으로 하였다. The high levels of combustion heat and applied loadings result in deformation during the engine operation. Subsequently, due to various loading conditions, the wear also occurs between valve and valve seat. The objective of the present study is to identify the major parameters that affect the valve seat wear via structural analysis of engine and valve. The finite element analysis is conducted using Hypermesh and ABAQUS. The loading conditions considered in the present study are bolt joining force, thermal loading, combustion pressure and valve closing force, etc. The numerical model includes as many as loading and contact conditions in order to accommodate the more realistic engine environment. The wear analysis is evaluated based on the well-known Archard’s equation.

일개 대학병원에서 수집한 스티븐스-존슨 증후군 및 독성표피괴사용해 70사례 분석

이재천 ( Jaechun Lee ),김재왕 ( Jae Wang Kim ) 대한내과학회 2017 대한내과학회지 Vol.92 No.2

목적: 스티븐스-존슨 증후군(SJS) 및 독성표피괴사용해(TEN)는 중증 피부약물이상반응이며, 치명적 결과를 유발할수 있다. 한 지역 기반의 대학병원에서 경험한 사례를 분석하였다. 대상 및 방법: 2008년부터 2014년까지 전문가에 의해 진단된 SJS/TEN 사례의 임상 양상, SCORTEN 등을 후향적으로 수집하였다. 결과: 7년간 SJS 56사례, TEN 14사례 등 총 70사례가 발생하였다. 40대에서 60대(남성 평균 55세, 여성 평균 54세)에 흔하게 발생하였으며, 흔한 원인 약제는 항전간제(42.8%), 탄산탈수효소저해제(20.0%), 항균제(15.7%), 알로푸리놀(7.1%), 진통소염제(7.1%) 등이었다. 독성표피괴사용해 7사례(50%)가 사망하였다. 사망 사례의 평균 연령은 67세였고, 남성(20%)보다 여성(67%)에서 흔하였다. 치명률은 SCORTEN으로 예측되었다. 생존 사례와 치료 방법에는 차이가 없었다. 결론: SJS/TEN의 원인약물 및 치명성에 대한 숙지가 필요하다. 고령 여성의 TEN에서 치명률이 높다. SCORTEN을 활용하여 치명률을 예측할 수 있다. 조기 발견 및 적절한 치료가 필수적이다. Background/Aims: Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are severe cutaneous adverse reactions that frequently result in fatal outcomes. We investigated cases of SJS and TEN in a regional hospital. Methods: From 2008 to 2014, SJS and TEN cases were enrolled retrospectively by allergy and dermatology specialists, and their clinical features and severity-of-illness score for TEN (SCORTEN) were assessed. Results: During the 7-year study period, 56 SJS and 14 TEN cases were recruited. The majority (71%) were 40-70 years of age (mean age of male and female patients, 55 and 54 years, respectively). Regarding drugs, anticonvulsants (42.8%) were the most frequently causative, followed by carbonic anhydrase inhibitors (20.0%), antimicrobials (15.7%), allopurinol (7.1%), and non-steroidal anti-inflammatory drugs (7.1%). No fatal case of SJS was seen. However, 7 of the 14 patients with TEN died (50%; mean age, 67 years; 1 of 5 [20%] males and 6 of 9 females [66.7%]). The mortality rate was reflected in the SCORTEN values. Vancomycin, allopurinol, methazolamide (two cases each) and megestrol (one case) were the causative drugs in the seven fatal TEN cases. Treatment modality did not affect the likelihood of death due to TEN. Conclusions: The causative drugs of, and frequency of mortality due to, SJS and TEN should be recognized by physicians. Elderly females with TEN are at high risk of mortality. SCORTEN values reflect the mortality rate of TEN patients. Early recognition and proper management of SJS and TEN may reduce the mortality rate. (Korean J Med 2017;92:171-176)

Development of a Gaze Fixation Identification Algorithm for Comparison of Performance of Gaze Fixation Induction Methods in Visual Field Testing

Jihyung Lee,Nahyun Lee,Jaechun Cho,Baekhee Lee,Kyunghyun Jin,Hyejee Kim,Younggyun Kim,Jaheon Kang,Heecheon You 대한인간공학회 2015 대한인간공학회 학술대회논문집 Vol.2015 No.10

Objective: The present study to evaluate an ergonomic gaze fixation induction method for gaze fixation during visual field testing developed and applied a gaze fixation identification algorithm to the gaze tracking data analysis. Background: Development of the gaze fixation identification algorithm is necessary to evaluate the degree of gaze fixation which is important for checking the reliabilities of visual field testing. Method: the present study investigated factors of gaze tracking data and developed an identification algorithm to identify gaze fixation. 32 men and women (29.0 ± 4.4 yr) participated in gaze fixation testing to evaluate three gaze fixation induction methods (black dot, flashing black dot, bulls eye and cross hair) in the aspects of correct fixation rate using gaze fixation identification algorithm. Results: It is necessary to analyze gaze location at 0.2 seconds intervals before and after target presenting for identify a gaze fixation in visual field testing. If one of two interval gaze trajectory is belong within visual angle 1° when the gaze tracking data analyzed in 0.2 seconds intervals before and after target presenting, the gaze fixation identification algorithm decide to fix the participant’s gaze to a fixation target when the target presents. Correct fixation rate of flashing black dot (91.5%) and bulls eye and cross hair (88.0%) are higher 5.5% and 1.5% than that of black dot (86.7%). Conclusion: The analysis using short interval gaze tracking data at before and after target presenting is more effective method in visual field testing for evaluating the degree of gaze fixation. Application: The gaze fixation identification algorithm is expected to be effectively used for monitor-based gaze tracking research.

피부시험으로 확인된 디클로페낙 아나필락시스

이재천 ( Jaechun Lee ) 대한천식알레르기학회(구 대한알레르기학회) 2021 Allergy Asthma & Respiratory Disease Vol.9 No.3

Nonsteroidal anti-inflammatory drugs (NSAIDs) are a major culprit of drug-induced hypersensitivity. No reliable diagnostic tests other than a direct challenge are available. Cross-reactivity among NSAIDs that inhibit cyclooxygenase-1 is common. However, in rare cases, the mechanism underlying hypersensitivity is immunologically understood, without involving cross-reactivity of NSAIDs or even with a positive skin test for an NSAID. A 55-year-old woman was referred to the Emergency Department for anaphylaxis. She suffered from generalized hives, chest tightness, and hypotension a few minutes after intramuscular diclofenac injection. One year before, she had experienced a similar reaction after intramuscular injection of aceclofenac. Thereafter, she had been taking naproxen as needed to relieve her osteoarthritis pain, without having an adverse reaction. To confirm drug hypersensitivity and to find alternative drugs, provocation tests were performed with acetaminophen, celecoxib, and lysine-aspirin. All tests were negative, and a skin prick test with diclofenac was also negative. However, intradermal injection of 0.05 mL (37.5 mg/mL) diclofenac provoked an anaphylactic shock and resulted in her admission. Here, we report a rare case of single NSAID-induced anaphylaxis, which was only triggered by acetic acid derivatives of NSAIDs, presumably by an immunoglobulin E-mediated reaction. (Allergy Asthma Respir Dis 2021;9:184-186)