DISCOVERY OF A FAINT QUASAR AT <i>z</i> ∼ 6 AND IMPLICATIONS FOR COSMIC REIONIZATION

Kim, Yongjung,Im, Myungshin,Jeon, Yiseul,Kim, Minjin,Choi, Changsu,Hong, Jueun,Hyun, Minhee,Jun, Hyunsung David,Karouzos, Marios,Kim, Dohyeong,Kim, Duho,Kim, Jae-Woo,Kim, Ji Hoon,Lee, Seong-Kook,Pak, IOP Publishing 2015 ASTROPHYSICAL JOURNAL LETTERS - Vol.813 No.2

<P>Recent studies suggest that faint active galactic nuclei may be responsible for the reionization of the universe. Confirmation of this scenario requires spectroscopic identification of faint quasars (M-1450 > -24 mag) at z greater than or similar to 6, but only a very small number of such quasars have been spectroscopically identified so far. Here, we report the discovery of a faint quasar IMS J220417.92+011144.8 at z similar to 6 in a 12.5 deg(2) region of the SA22 field of the Infrared Medium-deep Survey (IMS). The spectrum of the quasar shows a sharp break at similar to 8443 angstrom, with emission lines redshifted to z = 5.944 +/- 0.002 and rest-frame ultraviolet continuum magnitude M-1450 = -23.59 +/- 0.10 AB mag. The discovery of IMS J220417.92+011144.8 is consistent with the expected number of quasars at z similar to 6 estimated from quasar luminosity functions based on previous observations of spectroscopically identified low-luminosity quasars. This suggests that the number of M-1450 similar to 23 mag quasars at z similar to 6 may not be high enough to fully account for the reionization of the universe. In addition, our study demonstrates that faint quasars in the early universe can be identified effectively with a moderately wide and deep near-infrared survey such as the IMS.</P>

김치 유산균인 Lactobacillus sp. JJ-2001이 생산하는 Bacteriocin에 관한 연구

조영배,조우제,조영임,이은주,김성구,전홍기 부산대학교 유전공학연구소 1997 분자생물학 연구보 Vol.13 No.-

The microorganisms producing bacteriocin from kimch were screened, and among them,a strain showing the highest bacteriocin activity and stability was isolated. Based on the taxonomic characteristics of its morphological, cultural and physiological properties, the isolatef strain was characterized as Lactobacilius sp..To identify optimal conditions for the growth and the production of bacteriocin from the isolated strain,nutrient source, initial pH, and culture temperature were evaluated. Physiochemical properties of bacteriocin was also investigated. The potimal condition for the production of bacteriocin and the cell growth was obtained at 2% glucose, 1% beef extract as organic nitrogen source,1%(NH_4)_2SO_4 as inorganic nitrogen source,and 0.1% Tween 80. The isolated strain showed the maximum growth at 25℃. The inhibitory range of its antimicrobial substance aginst gram positive bacteria was marrow and its inhibitory activity was maintained between pH3.0 and pH8.0. The antimicrobial activity of bacteriocin from the isolated strain was stable at 50℃.

Deletion of Chitinase-3-like 1 accelerates stroke development through enhancement of Neuroinflammation by STAT6-dependent M2 microglial inactivation in Chitinase-3-like 1 knockout mice

Im, Jun Hyung,Yeo, In Jun,Park, Pil Hoon,Choi, Dong Young,Han, Sang-Bae,Yun, Jaesuk,Hong, Jin Tae Elsevier 2020 Experimental neurology Vol.323 No.-

<P><B>Abstract</B></P> <P>Chitinase 3-like 1 (Chi3L1) plays a major role in the pathogenesis of inflammatory diseases. We investigated the effect of Chi3L1 knockout on stroke development. Ischemia/reperfusion was induced by middle cerebral artery occlusion (MCAO) in Chi3L1 knockout and wildtype mice. Significantly increased infarct volume and decreased neurological deficit scores at 24 h after ischemia/reperfusion were found in Chi3L1 knockout mice compared to wildtype mice. Moreover, ischemic neuronal cell death was increased in Chi3L1 knockout mice through increased oxidative stress and release of IL-6 and IL-1β but IL-10 and IL-4 were reduced. Furthermore, expression of inflammation-related proteins (iNOS, COX-2, Iba-1, and GFAP) was significantly increased in Chi3L1 knockout mice compared to wildtype. In microglia isolated from MCAO-injured Chi3L1 knockout mice, expression of M1 markers (iNOS, CD86, IL-1β, and IL-6) was increased and M2 markers (Arg1, Mrc1, IL-10, and IL-4Ra) was decreased. In BV-2 cells, knockdown of Chi3L1 increased TNF-α- and INF-γ-induced expression of iNOS, COX-2, and Iba-1, but decreased the expression of Arg1, MRC1, and IL-4 receptor-alpha (IL-4Rα). Expression of IL-4Rα, an important factor of M2 polarization, and its downstream signals p-JAK1, p-JAK3, and p-STAT6, was much reduced in the knockout mice. Additionally, in BV-2 cells, knockdown of Chi3L1 by siRNA Chi3L1 decreased rhTNF-α- and INF-γ-induced expression of IL-4Rα, p-JAK1, p-JAK3, and p-STAT6. Furthermore, treatment with AS1517499 abolished Chi3L1 knockdown-induced reduced IL-4Rα and Arg1 but not CD86 expression. Our results indicate that deletion of Chi3L1 accelerates stroke development through enhancement of neuroinflammation by markedly decreasing STAT6-dependent M2 macrophage polarization.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Chi3L1 is important for IL-4Rα expression and phosphorylation of STAT6, affecting micorglial M2 polarization. </LI> <LI> Knockdown of Chi3L1 decrease IL-4Rα, p-JAK1, p-JAK3, and p-STAT6 expression level which blocking microglial M2 polarization. </LI> <LI> Absence of Chi3L1 accelerates stroke development through STAT6 dependent M2 microglia inactivation. </LI> </UL> </P>

PEGylated Erythropoietin Protects against Brain Injury in the MCAO-Induced Stroke Model by Blocking NF-κB Activation

( Jun Hyung Im ),( In Jun Yeo ),( Chul Ju Hwang ),( Kyung Sun Lee ),( Jin Tae Hong ) 한국응용약물학회 2020 Biomolecules & Therapeutics(구 응용약물학회지) Vol.28 No.2

Cerebral ischemia exhibits a multiplicity of pathophysiological mechanisms. During ischemic stroke, the reactive oxygen species (ROS) concentration rises to a peak during reperfusion, possibly underlying neuronal death. Recombinant human erythropoietin (EPO) supplementation is one method of treating neurodegenerative disease by reducing the generation of ROS. We investigated the therapeutic effect of PEGylated EPO (P-EPO) on ischemic stroke. Mice were administered P-EPO (5,000 U/kg) via intravenous injection, and middle cerebral artery occlusion (MCAO) followed by reperfusion was performed to induce in vivo ischemic stroke. P-EPO ameliorated MCAO-induced neurological deficit and reduced behavioral disorder and the infarct area. Moreover, lipid peroxidation, expression of inflammatory proteins (cyclooxygenase-2 and inducible nitric oxide synthase), and cytokine levels in blood were reduced by the P-EPO treatment. In addition, higher activation of nuclear factor kappa B (NF-κB) was found in the brain after MCAO, but NF-κB activation was reduced in the P-EPO-injected group. Treatment with the NF-κB inhibitor PS-1145 (5 mg/kg) abolished the P-EPO-induced reduction of infarct volume, neuronal death, neuroinflammation, and oxidative stress. Moreover, P-EPO was more effective than EPO (5,000 U/kg) and similar to a tissue plasminogen activator (10 mg/kg). An in vitro study revealed that P-EPO (25, 50, and 100 U/mL) treatment protected against rotenone (100 nM)-induced neuronal loss, neuroinflammation, oxidative stress, and NF-κB activity. These results indicate that the administration of P-EPO exerted neuroprotective effects on cerebral ischemia damage through anti-oxidant and anti-inflammatory properties by inhibiting NF-κB activation.

교육성취의 아파트가격에 대한 영향: 서울시 사례분석

임준홍 ( Jun Hong Im ),홍성효 ( Sung Hyo Hong ) 한국부동산분석학회 2015 不動産學硏究 Vol.21 No.1

There are a number of empirical studies on the influence of educational factors on housing prices. However, previous studies have overlooked the possibility that there exists a large lag in the effect of education on housing prices due to shortterm inefficiencies in the real estate market. Results show that educational achievement from one or two years ago has the largest and most meaningful effect on present apartment prices. If the interval between the date of apartment price observation and the date when educational achievement is actually reflected in housing prices is insufficient, there is a risk of underestimating the effect of educational factors on apartment prices. In the case of estimating the housing price function through the ‘hedonic price model``, all factors and circumstance significant to the individual characteristics of each house must be controlled in order to estimate the effect of explanatory variables without any bias. However, it is practically impossible to include all significant factors in the regression analysis. To mitigate this problem, only houses located near the border of two different school districts were considered in this study, just like the research method of Black(1999). Adjacent houses share not only similar individual characteristics but also similar circumstances. Therefore any possibility of distorted estimates of educational factors`` influence on housing prices can be minimized since such distortions usually occur when explanatory variables are omitted from the regression formula.

우심실 조율 시 QRS파 폭과 조율 장소에 따른 급성 혈역학적 변화

홍영준 ( Hong Yeong Jun ),양보라 ( Yang Bo La ),심두선 ( Sim Du Seon ),임상엽 ( Im Sang Yeob ),이상현 ( Lee Sang Hyeon ),임지현 ( Im Ji Hyeon ),김한균 ( Kim Han Gyun ),박옥영 ( Park Og Yeong ),김주한 ( Kim Ju Han ),김원 ( Kim Won 대한내과학회 2004 대한내과학회지 Vol.66 No.2

배경 및 목적 : 장기적인 우심실 조율 후 심기능 저하가 발생할 수 있으며 이는 조율 시 QRS파 폭의 연장과 밀접한 관계가 있음이 보고된 바 있다. 본 연구는 영구형 인공 심박 조율 치료 시 심기능 저하를 극소화 할 수 있는 조율 방법을 개발하고자 다양한 장소에서 우심실을 조율하고 우심실 조율에 따른 급성 혈역학적 변화를 관찰하였다. 대상 및 방법 : 부정맥을 제외한 다른 심장질환이 없었던 14명의 발작성 심실상성 빈맥증 환자(연령: 47.1±9.6세 Background : Intraventricular conduction disturbances, as manifested by increased QRS duration, are common in patients with advanced left ventricular (LV) dysfunction and adversely affect LV systolic and diastolic function. It has been reported that the p

도심 거주의향과 지역 내 소비지출에 관한 실증분석

임준홍(Jun-Hong Im),홍성효(Sung-Hyo Hong) 한국콘텐츠학회 2017 한국콘텐츠학회논문지 Vol.17 No.2

본 연구는 원도심 활성화를 위해서는 타 지역으로부터의 인구유치도 중요하지만 이보다는 원주민들을 위한 전략이 필요하다는 관점에서 이루어 졌다. 실증분석은 내포신도시와 인접하여 도심공동화 현상이 우려되는 홍성군과 예산군의 원도심 주민을 대상으로 하였다. 분석결과, 원도심에서 계속 거주하기를 원하는 사람은 고령자와 단독주택 거주자였으며 반면, 내포신도시로의 이주를 희망하는 사람은 30대와 고소득자였다. 이에 우선적으로 고령자를 대상으로 한 주거정책 개발, 단독주택을 중심으로 한 주거지 정비가 요구된다. 이와 더불어 활발한 경제주체인 30대와 고소득자의 주거이탈을 줄이기 위한 전략도 요구된다. 특히, 이탈자 1인당 연간 55.3만원에 해당하는 원도심에서의 소비지출이 감소하는 것으로 추정되기 때문에, 주민 이탈이 계속될 경우 상권약화는 물론 지역경제를 근본적으로 위협할 수 있다. 이에, 지방정부는 인구감소 및 인구구조 변화, 한정된 예산의 적절한 배분, 지속가능한 도시발전에 대한 고민 등을 종합적으로 검토하여 도시재생정책 방향을 설정하여야 할 것이다. This study is performed with the view point that a strategy to maintain the existing residents as well as to attract people outside is necessary in order to revitalize the downtown of an area. Empirical analyses of this study are focused on the residents in downtowns of the two counties, Hongsung and Yesan which are concerned of becoming hollow. According to the results, the residents who want to continue living in the downtown are the old and the owner-occupants of detached housing units while those who hope to leave to Naepo, a neighboring new town are in their 30’s or high income-earners. Thus, policies such as renovating detached housing for the old are required. In addition, policies to reduce outflow of the people who are in their 30’s or high income-earners are also needed. Especially, since the resident who is highly probable to leave is estimated to spend 553 thousand Korean Won per year in the downtown, on-going outflow of residents would weaken the local market and threaten the local economy. Consequently, local governments need to set up directions of urban renovation policies by considering decline in population, change in demographic structure, appropriate allocation of limited budget, and sustainable urban development based on empirical research results.

도심거주의 선호자 및 선호유형에 관한 연구

임준홍(Im Jun-Hong),김한수(Kim Han-Su) 대한국토·도시계획학회 2001 國土計劃 Vol.36 No.6

의료 관련 생활SOC의 지역별 격차분석 : 충청남도를 중심으로

임준홍(Im, Jun-hong) 한국주거학회 2020 한국주거학회 학술대회논문집 Vol.32 No.2

This study analyzes the gap between the quantitative and qualitative levels of medical services and their relationship. To analysis the quantitative level of medical facilities, we used the location data of the six types of medical facilities provided by the National Geographic Information Institute and the population data provided by Statistics Korea. Also, to analyze the quality level of satisfaction with the use of medical facilities, we used satisfaction survey data of the Chungnam Social Indicators Survey. The analysis results are as follows. An analysis of the won-unit of medical facilities (the number of facilities per population) showed that Asan City, adjacent to Cheonan City, the largest city in Chungchoennam-do Province, also lacked medical facilities. As a result of the analysis of the relationship between the quantitative and qualitative levels of medical facilities, Cheongyang-gun and Buyeo-gun, which have the strongest rural characteristics in Chungnam, and Taean, Seosan, and Dangjin, which are Seosan-area based on the medical standard, were analyzed having week medical facilities.

청년 1인가구의 주거환경만족도와 주거이동의향 실증분석 : 도시와 농촌 차이

임준홍(Im, Jun-hong) 한국주거환경학회 2021 주거환경(한국주거환경학회논문집) Vol.19 No.1

This study divides the residential areas of young one-person households living in Chuncheongnam-do into urban and rural areas, and analyzes the degree to which they are satisfied with their residential environment and they intend to migrate. The key findings are as follow: First, there is no difference in residential environment satisfaction among living areas (cities and rural areas). Although urban residents’ satisfaction (5.56 out of 10) is higher than that of rural residents (5.47), it is not statistically significant. Second, according to the results of the analysis by residential environment factors, urban residents are more satisfied with the access to living facilities, while rural residents are more satisfied with the air, noise, and green areas. Third, depending on the living area of young one-person households, urban residents’ intention of the residential movement is higher than that of rural residents. Fourth, the analysis on the factor that affects the satisfaction of the residential environment shows that all four types of housing factors have a statistically significant positive effect. In particular, convenience facility factors have a greater impact than other factors, which are common in urban and rural areas. Fifth, as the result of analyzing the determinants of the intention to move around, urban residents are not greatly affected by certain factors, and rural residents are greatly influenced by cultural tourism and sports factors. Young one-person households are very important for maintaining urban vitality and strengthening residential stability. In particular, considering the high cost of housing for young people, various housing policies in the supply-side for young people and the maintenance of the residential environment that can attract young people are required. 본 연구는 충남에서 생활하는 청년 1인가구의 거주지역을 도시와 농촌으로 구분하여 주거환경만족도와 주거이동의향에 대해 실증분석하였다. 주요 연구결과는 다음과 같다. 첫째, 청년 1인가구는 생활지역(도시와 농촌)에 따라 주거환경만족도의 차이는 없다. 즉, 도시생활자가(5.56)가 농촌생활자(5.47)보다 높았지만 통계적으로는 유의하지 않다. 둘째, 주거환경 요인별 분석결과, 도시생활자는 생활편의시설의 이용 만족도가 높은데 반해, 농촌생활자는 대기, 소음진동, 녹지에 대한 만족도가 높다. 셋째, 청년 1인가구의 생활지역에 따라 주거이동의향은 도시생활자가 농촌생활자보다 높다. 넷째, 주거환경 만족도에 영향을 주는 요인을 분석한 결과 4가지 주거요인 모두 통계적으로 유의하게 정(+)의 영향 준다. 특히, 편의시설요인이 다른 요인들에 비해 큰 영향을 주고, 이는 도시지역과 농촌지역에서 공통적이다. 다섯째, 주거이동 의향 결정요인을 분석한 결과, 도시지역 생활자는 특정 요인에 큰 영향을 받지 않고, 농촌지역 생활자는 문화관광스포츠요인에 많은 영향을 받는다. 청년 1인가구는 도시활력 유지와 거주안정성 강화 측면에서 매우 중요하다. 특히, 청년의 높은 주거비 부담을 높은 것을 고려할 때, 청년들을 위한 다양한 주택공급, 청년들에게 매력을 줄 수 있는 주거환경 정비가 요구된다.