비동맥염성 앞허혈시신경병증에서 동반된 망막하액 축적 1예

조인환,김훈동,최경식.In Hwan Cho. MD. Hoon Dong Kim. MD. Kyung Seek Choi. MD 대한안과학회 2010 대한안과학회지 Vol.51 No.10

Purpose: To report a patient with non-arteritic anterior ischemic optic neuropathy with submacular fluid and peripapillary swelling. Case summary: A 53-year-old patient visited our clinic complaining of acute visual loss in the right eye which began two days previously. The patient had no clinical history of ocular pain on eye movement. A relative afferent pupillary defect was observed in the right eye. Fundoscopic examination showed optic disc edema and an elevated macular lesion (1 disc diameter). Fluorescein angiography (FAG) revealed blocking by serous detachment in the peripapillary area in the early phase and peripapillary leakage in the late phase. Spectral domain optical coherence tomography (SD-OCT) showed submacular fluid and peripapillary swelling. Intravenous steroid injection was administrated. After five days of treatment, visual acuity improved to 0.2; one month later, visual acuity was 0.5. subretinal fluid absorption was observed with remaining lipid deposits. Conclusions: In non-arteritic anterior ischemic optic neuropathy, submacular fluid accumulation can occur due to destruction of retinal glial cells. Accumulation of submacular fluid can induce sudden visual loss and may predict visual prognosis. The macular area requires careful evaluation in non-arteritic anterior ischemic optic neuropathy patients. J Korean Ophthalmol Soc 2010;51(10):1409-1413

망막중심정맥폐쇄에서 유리체강내 베바시주맙 주사 전 후에 망막전위도를 통한 망막기능의 평가

조인환,박태관,온영훈,In Hwan Cho,Tae Kwann Park,Young-Hoon Ohn 대한안과학회 2011 대한안과학회지 Vol.52 No.9

Purpose: To investigate the changes of electroretinogram (ERG) at baseline and during the first 3 injections of intravitreal bevacizumab in central retinal vein occlusion (CRVO) patients. Methods: Thirteen eyes of 13 CRVO patients who received 3 injections of intravitreal bevacizumab at 6-week intervals and who could be examined for visual acuity, optical coherence tomography and ERG at 4 weeks after each injection were included in the present study. In addition, the ERG results of the unaffected fellow eyes group at 4 weeks after each injection were compared with the CRVO eyes group. Results: Amplitudes of rod b wave, a and b waves of maximal combined response and cone response, oscillatory potentials and 30-Hz flicker significantly decreased in the CRVO eyes group than the fellow eyes group at 4 weeks after each injection (<em>p</em> < 0.001). After injection, amplitudes of all the above-mentioned ERG parameters gradually increased during the 1st and the 2nd injection (<em>p</em> < 0.001). However, there was no significant difference at 4 weeks after the 2nd and 3rd injections (<em>p</em> > 0.05). Conclusions: After intravitreal bevacizumab injection, macular functions significantly improved and amplitudes of all ERG parameters gradually increased in CRVO patients. J Korean Ophthalmol Soc 2011;52(9):1055-1062

Zn-Sn-O 박막 트랜지스터의 전기적 특성에 대한 전자빔 조사의 영향

조인환,조경일,최준혁,박해웅,김찬중,전병혁,Cho1, In-Hwan,Jo, Kyoung-Il,Choi, Jun Hyuk,Park, Hai-Woong,Kim, Chan-Joong,Jun, Byung-Hyuk 한국재료학회 2017 한국재료학회지 Vol.27 No.4

The effect of electron beam (EB) irradiation on the electrical properties of Zn-Sn-O (ZTO) thin films fabricated using a sol-gel process was investigated. As the EB dose increased, the saturation mobility of ZTO thin film transistors (TFTs) was found to slightly decrease, and the subthreshold swing and on/off ratio degenerated. X-ray photoelectron spectroscopy analysis of the O 1s core level showed that the relative area of oxygen vacancies ($V_O$) increased from 10.35 to 12.56 % as the EB dose increased from 0 to $7.5{\times}10^{16}electrons/cm^2$. Also, spectroscopic ellipsometry analysis showed that the optical band gap varied from 3.53 to 3.96 eV with increasing EB dose. From the results of the electrical property and XPS analyses of the ZTO TFTs, it was found that the electrical characteristic of the ZTO thin films changed from semiconductor to conductor with increasing EB dose. It is thought that the electrical property change is due to the formation of defect sites like oxygen vacancies.

InGaZnO 박막 트랜지스터의 전기 및 광학적 특성에 대한 전자빔 조사의 영향

조인환,박해웅,김찬중,전병혁,Cho, In-Hwan,Park, Hai-Woong,Kim, Chan-Joong,Jun, Byung-Hyuk 한국재료학회 2017 한국재료학회지 Vol.27 No.6

The effects of electron beam(EB) irradiation on the electrical and optical properties of InGaZnO(IGZO) thin films fabricated using a sol-gel process were investigated. As the EB dose increased, the electrical characteristic of the IGZO TFTs changed from semiconductor to conductor, and the threshold voltage values shifted to the negative direction. X-ray photoelectron spectroscopy analysis of the O 1s core level showed that the relative area of oxygen vacancies increased from 14.68 to 19.08 % as the EB dose increased from 0 to $1.5{\times}10^{16}electrons/cm^2$. In addition, spectroscopic ellipsometer analysis showed that the optical band gap varied from 3.39 to 3.46 eV with increasing EB dose. From the result of band alignment, it was confirmed that the Fermi level($E_F$) of the sample irradiated with $1.5{\times}10^{16}electrons/cm^2$ was located at the closest position to the conduction band minimum(CBM) due to the increase of electron carrier concentration.

Li 도핑된 ZnSnO 박막 트랜지스터의 전기 및 광학적 특성에 대한 고속 중성자 조사의 영향

조인환,김찬중,전병혁,Cho, In-Hwan,Kim, Chan-Joong,Jun, Byung-Hyuk 한국재료학회 2020 한국재료학회지 Vol.30 No.3

The effects of fast neutron irradiation on the electrical and optical properties of Li (3 at%) doped ZnSnO (ZTO) thin films fabricated using a sol-gel process are investigated. From the results of Li-ZTO TFT characteristics according to change of neutron irradiation time, the saturation mobility is found to increase and threshold voltage values shift to a negative direction from 1,000 s neutron irradiation time. X-ray photoelectron spectroscopy analysis of the O 1s core level shows that the relative area of oxygen vacancies is almost unchanged with different irradiation times. From the results of band alignment, it is confirmed that, due to the increase of electron carrier concentration, the Fermi level (E_F) of the sample irradiated for 1,000 s is located at the position closest to the conduction band minimum. The increase in electron concentration is considered by looking at the shallow band edge state under the conduction band edge formed by fast neutron irradiation of more than 1,000 s.

금강권역 주요 하천의 돌부착돌말류 분포 및 출현예측

조인환 ( In Hwan Cho ),김하경 ( Ha Kyung Kim ),최만영 ( Man Young Choi ),권용수 ( Yong Su Kwon ),황순진 ( Soon Jin Hwang ),김상훈 ( Sang Hoon Kim ),김백호 ( Baik Ho Kim ) 한국하천호수학회(구 한국육수학회) 2015 생태와 환경 Vol.48 No.3

In order to understand the relationship between the distribution of epilithic diatoms and the habitual environments, land-use, water qualities, and epilithic diatoms were studied at 141 sampling sites in the midwestern stream of Korean peninsula (Geum river, Mangyeong river, Dongjin river, and Sapgyo river). The total 183 diatom taxa was appeared in the study, while the dominant species were found to be Nitzschia palea (10.9%) and Achnanthes convergens (8.4%). Based on the abundance of epilithic diatoms, a cluster analysis results indicate that the sampling sites divided the sampling sites into 4 groups (G) at the 25% level. In term of geographic and aquatic environments, G-I and -II accounted for the upper and mid streams of the Geum river, and had large forest areas and good in water quality. G-III accounted for farmland and urban, and high concentration nutrient levels (TN and TP) and electric conductivity. G-IV accounted for mostly farmland, and high levels in turbidity, BOD, nutrient and electric conductivity. CCA results showed that the saproxenous taxa Meridion circulare was the indicator species of G-I, which strongly influenced by altitude and forests. In G-II, the indifferent taxa Navicula cryptocephala was influenced by Chl-a, AFDM, and DO. In G-III and -IV, the indifferent taxa Fragilaria elliptica and saprophilous taxa Aulacoseira ambigua were influenced by electric conductivity, turbidity, and nutrient counts. Meanwhile, random forest results showed that the predicting factor of indicator species appearance in G-I, -II, and -III was found to be electric conductivity whereas in G-IV it was found to be turbidity. Collectively, the distribution of diatoms in the midwestern of Korean peninsula was found to depend more on the land-use and its subsequent water qualities than the inherent characteristics of the aquatic environment.

북한강 수계의 남조 Anabaena 대발생과 강우의 관계

변정환 ( Jeong Hwan Byun ),조인환 ( In Hwan Cho ),황순진 ( Soon Jin Hwang ),박명환 ( Myung Hwan Park ),변명섭 ( Myeong Seop Byeon ),김백호 ( Baik Ho Kim ) 한국하천호수학회 2014 생태와 환경 Vol.47 No.2

To evaluate the relationship between dynamics of Cyanobacterial bloom and rainfalls, a monthly monitoring of water quality and phytoplankton from the three serial lakes (Lake Ui-am, Lake Chung-pyeong and Lake Pal-dang) in the North Han River System were examined 12 times from May 2012 to March 2013. A dense bloom of cyanobacterium Anabaena spp., was occurred over three lakes in the summer season of 2012. In Lake Ui-am, the Anabaena population appeared in June, showed a peak in July (43,850 cells mL-1) and disappeared in November 2012. In Lake Chung-pyeong and Lake Pal-dang, Anabaena population commonly appeared in July, showed the peaks (31,648 cells mL-1 and 7,136 cells mL-1, respectively) in August, and entirely disappeared in September 2012. Over the three lakes, the phytoplankton community was commonly dominated by diatoms before Monsoon, cyanobacteria during Monsoon, and diatoms after Monsoon, respectively, indicating a Monsoon-dependent succession. A correlation analysis revealed that dynamics of Anabaena population was strongly related with rainfall (r=0.72, r=0.83, r=0.88, P.0.01 for three lakes), and partly with nutrients, inflow and outflow of lakes. Therefore, this study indicates that the outbreak and destruction of Anabaena bloom in North Han River System between 2012 and 2013 was impacted by rainfalls. However, a high density of cyanobacteria in Lake Ui-am remained after Monsoon, and thus, may produce bad-order and toxins from phytoplankton.

금강수계의 토지이용 및 수질구배에 따른 돌부착 돌말류의 분포특성

조인환 ( In Hwan Cho ),황순진 ( Soon Jin Hwang ),김백호 ( Baik Ho Kim ),김용재 ( Yong Jae Kim ) 한국물환경학회 2014 한국물환경학회지 Vol.30 No.3

To study the distribution characteristics of diatom communities in relation to the gradient of water quality and land-use, water samples and epilithic diatoms were collected from 90 sites including mainstream and tributaries, in the Geum River System (GRS) during no rainfall, May 2011. Of 239 taxa identified, Achnanthes convergens and Cymbella minuta were dominated over all the sites. Cluster analysis on the GRS divided into three groups. Group 1 (G1) is the mountainous upstream, a relatively good water quality, and mainly consisted of saproxenous species. Group 2 (G2) is the urban sites, polluted (high in electric conductivity, total phosphate and soluble reactive phosphorus), and saproxenous and common species. Group 3 (G3) is the agriculture sites, and polluted (turbidity, total nitrogen, nitrate), and saprophilous species. There were some discrepancies between abiotic and biotic variables in GRS; biologically similar between G1 and G2, but abiotically similar between G2 and G3. These differences may attribute to not only physiological characteristics of diatom cells, but complicate relationships between microhabitat and water quality. Thus, an urgent development of generalized or standardized methods to diminish the differences between epilithic diatom community and environments is advent.

국내 미숙아망막병증의 발생률과 발생 시기에 관한 분석

김민성(Min Seong Kim),조인환(In Hwan Cho),김소영(So Young Kim) 대한안과학회 2023 대한안과학회지 Vol.64 No.5

목적: 국내 미숙아망막병증의 발생률과 발생 시기에 대해 분석하고자 하였다. 대상과 방법: 2006년부터 2018년까지 신생아 중환자실에 입원한 미숙아를 대상으로 의무기록을 후향적으로 검토하였다. 중증도 차이를 확인하기 위해 경도의 미숙아망막병증과 중증도 이상의 미숙아망막병증으로 분류하여 분석하였다. 미숙아망막병증 환아의 임상적특징, 병기에 따른 임상적 특징, 미숙아망막병증과 출생 시 체중, 재태연령 간의 연관성, 치료받은 환아의 임상적 특징을 분석하였다. 결과: 미숙아망막병증 발생률은 10.9%였고, 평균 월경후연령 34.92주에 진단되었으며, 중증도 이상의 미숙아망막병증 빈도는 44.97% 였다. 출생 시 체중과 재태연령은 정상 환아보다 미숙아망막병증 환아가 유의하게 적었고, 경도의 미숙아망막병증보다 중증도 이상의미숙아망막병증에서 유의하게 적었다. 출생 시 체중별, 재태연령별로 미숙아망막병증 발생률과 중증도는 출생 시 체중 1,000 g 미만, 재태연령 27주 미만에서 높은 경향을 보였다. 레이저광응고술을 치료받은 환아의 빈도는 4.51%였는데, 평균 월경후연령 33.75주에미숙아망막병증으로 진단되었고, 35.06주에 1형 미숙아망막병증으로 진행되었으며, 36.04주에 치료를 시행하였다. 결론: 고위험 미숙아 생존율의 증가로, 특히 출생 시 체중 1,000 g 미만, 재태연령 27주 미만의 미숙아에서 미숙아망막병증의 발생률과 중증도가 증가하였음을 알 수 있다. 또한 미숙아망막병증이 주로 발생하는 시기인 월경후연령 32주부터 36주까지는 모든 미숙아에서 미숙아망막병증의 발생을 주의 깊게 관찰하여야 한다. Purpose: This study examined the incidence and time of onset of retinopathy in premature infants in Korea. Methods: The medical records of premature infants admitted to the neonatal intensive care unit from 2006 to 2018 were reviewed retrospectively. Stages 1 and 2 were classified as mild retinopathy and stages 3 and 4 were considered severe. The incidence, severity, time of diagnosis, associations between retinopathy and birth weight and also gestational age, and clinical characteristics of the treated infants were analyzed. Results: The incidence of retinopathy was 10.9% with an average time of diagnosis at 34.92 weeks postmenstrual age; the frequency of severe retinopathy was 44.97%. Birth weight and gestational age were significantly lower in premature infants with retinopathy than in normal infants. In addition, birth weight was significantly lower in those with severe retinopathy than in those with mild retinopathy. For birth weight and gestational age, the incidence and severity of retinopathy tended to be higher in those with birth weights less than 1,000 g and gestational ages of less than 27 weeks. Of the infants, 4.51% underwent laser photocoagulation; the times of diagnosis, progression to type 1 retinopathy, and treatment were 33.75, 35.06, and 36.04 weeks postmenstrual age, respectively. Conclusions: The incidence and severity of retinopathy of premature infants increased in those with birth weights less than 1,000 g and gestational ages less than 27 weeks. Such infants should be monitored carefully between 32 to 36 weeks of postmenstrual age, when retinopathy is mainly diagnosed.

분진-미스트 시스템을 이용한 실시간 수용성 유기탄소 분석

조인환(In-Hwan Cho),박다정(Da-Jeong Park),배민석(Min-Suk Bae) 한국대기환경학회 2015 한국대기환경학회지 Vol.31 No.6