Ocular immune privilege is maintained by constitutive expression of inhibitory molecules such as ... more Ocular immune privilege is maintained by constitutive expression of inhibitory molecules such as TGF-b, FAS and FAS-ligand. Here, we describe a model of immune privilege for the eye based on IL-27-induced suppression of Th17 responses. We show that Th17 cells are elevated in retina of mice during experimental autoimmune uveoretinitis (EAU) and treatment with anti-IL17 Abs reduces EAU severity. It is of note that the increase and subsequent trafficking of Th17 cells into the retina during EAU is accompanied by corresponding increases in IL-27 and IFN? in the retina. We further show that IL-27 is constitutively expressed in human or mouse retina and that IFN? upregulates its expression in retinal cells. Of particular interest is inhibition of the proliferation of uveitogenic Th17 cells by IL-27, suggesting that IFN? may mitigate uveitis by antagonizing Th17 expansion through induction of IL-27 in the target tissue. In a co-culture system the expansion of Th17 cells (propagated under T...
This study was carried out of investigate the effect of weed control methods on the growth of 'ca... more This study was carried out of investigate the effect of weed control methods on the growth of 'campbell early' grape at the vineyards which was divided into the 18 zone (3.5 m × 5.5 m/zone) in the grape research institute. It's investigated control effects, growth and quantity of grape and dominant weed of July~August by sprayed glufosinate ammonium and paraquat dichloride each 3 times, fabric covering, grass planting (Festuca myuros), mechanical weeding (3 times). The weed showed total of 16 species at the vineyards. Late-May to early growth stage of grape was dominated Chenopodium album and Trifolium repens, but to late growth stage of grape from mid-July was dominated Erigeron canadensis, Echinochloa crus-galli and Chenopodium album. Weed control effect of 10 day after treatment showed fabric covering 100%, grass planting (Festuca myuros L.) 95.3%, mechanical weeding 81.9%, glufosinate ammonium (3 times) 98.1% and paraquat dichloride (3 times) 90.4%, respectively. Growth of grape was higher herbicides treatment and mechanical weeding than others. Yield tended to be higher glufosinate ammonium (3 times) and paraquat dichloride (3 times) each 12.6 kg/tree, 12.3 kg/tree than others.
Ocular infection of Herpes Simplex Virus-I (HSV-1) causes Herpetic Stromal Keratitis (HSK), which... more Ocular infection of Herpes Simplex Virus-I (HSV-1) causes Herpetic Stromal Keratitis (HSK), which is a leading cause of infectious blindness. Although complex interactions of molecular and cellular events involve in the development of HSK, it has been known that angiogenesis is a key step for the HSK pathogenesis. Treatment of neutralizing antibody against vascular endothelial ° growth factor (VEGF) to inhibit VEGF activity reduced angiogenesis and HSK severity caused by infection of HSV-1 in mouse eyes. In addition, inactivation of cytokine which induces VEGF production and angiogenesis also reduced angiogenesis and HSK severity. Therefore, it has been proposed that VEGF or molecules which induce VEGF production or angiogenesis can be good target molecules for treating HSK. In this study, we investigated whether targeting VEGF or IL-1 receptor type I (IL-lRI) using RNAi technology could reduce angiogenesis in mouse eyes. A general introduction and overview of RNAi were provided in ...
A computer program written in the VPython language on the Glow Script platform is developed with ... more A computer program written in the VPython language on the Glow Script platform is developed with a view to aiding the study of vibrations and the waves. It simulates the forced motions of coupled oscillators of arbitrarily large number. Understanding the harmonic oscillations of physical systems underlies the core curriculum of college physics. It normally starts with the simple harmonic oscillation of a single oscillator and, afterwards, adds damping and external harmonic forcing. More than one coupled oscillators are, then, introduced and they give ways for understanding waves in continuous media as the number of oscillators becomes large. The reported product visualizes the motions of coupled oscillators and enhance the comprehension of such concepts as the normal modes of vibration and stationary waves.
Enhanced expression of integrin a v b 3 is commonly used as a biomarker for angiogenesis, which i... more Enhanced expression of integrin a v b 3 is commonly used as a biomarker for angiogenesis, which is one of the key pathophysiologic processes in cerebral infarct. Integrin a v b 3 can be imaged with arginine-glycine-aspartic acid (RGD) peptide agents. In this study, characteristics of positron emission tomography (PET) using a 68 Ga-labeled RGD were investigated in pediatric cerebral infarct. Pediatric patients with moyamoya disease underwent 68 Ga-RGD PET in a research protocol for neovascularization evaluation. In these patients, 17 cerebral infarct lesions of 10 patients were included in the analysis. On 68 Ga-RGD PET, the infarct lesion to contralateral brain ratio (LCR) of the infarct lesion was measured and analyzed with regard to postinfarct time interval (PTI) and perfusion single-photon emission computed tomography (SPECT) findings. An increase in 68 Ga-RGD uptake was observed in cerebral infarct, particularly in recent lesions. The LCR was significantly higher in the recent than in the chronic lesions, and a significant correlation existed between the LCR and PTI. Additionally, the LCR was significantly higher in the lesions with hyperperfusion on SPECT. This study, as the first human study using an RGD agent for in vivo cerebral infarct imaging, demonstrated that 68 Ga-RGD PET has a potential for molecular imaging of integrin a v b 3 expression in cerebral infarct as a biomarker of angiogenesis.
Journal of the Korean Society of Hazard Mitigation, 2018
Colombia has experienced many problems in its urban areas due to increase in population in these ... more Colombia has experienced many problems in its urban areas due to increase in population in these areas. In particular, because of recurring slope disasters in urban areas, it has become necessary for the Colombian government to analyze these hazards. In this study, we selected a test bed with a high-potential source area in the small and medium city and conducted the physical vulnerability assessment of the test bed. First, we collected and analyzed the causal factors and landslide inventory. Using the landslide inventory and spatial information database, we performed a susceptibility assessment to identify high-potential landslide source areas. Next, we defined the parameters (travel angle, maximum velocity, etc.) for the Flow-R model analysis, which we used to calculate the propagation zone of debris flow. For the vulnerability assessment, we used road sections to define the boundary zones. Finally, we developed and evaluated the physical vulnerability map of Soacha using the propagation zones of debris flow and the boundary zones. The physical vulnerability assessment technique developed through this study will provide useful information for future urban planning and disaster prevention in Colombia.
The structural and electro-optical influence of marcasite on the properties of solution-processed... more The structural and electro-optical influence of marcasite on the properties of solution-processed iron pyrite thin films was investigated. Marcasite has a strong tendency to form simultaneously with pyrite upon sulfurization of amorphous iron-oxide precursor films, leading to a mixed-phase structure in which pyrite grains are surrounded by nanocrystalline marcasite boundaries. The optical analysis in combination with spectroscopic ellipsometry revealed that marcasite should have a bandgap of approximately 0.85-0.88 eV with a higher absorption coefficient than pyrite, differing strongly from the prior belief that marcasite has a bandgap of less than 0.4 eV. In addition, the pyrite/marcasite film has been found to have a larger diffusion coefficient for photogenerated minority carriers than the phase-pure pyrite film from electrochemical impedance analyses, resulting in a higher photocurrent density, as determined through photoelectrochemical measurement. The facile transport of a minority carrier along the marcasite boundaries is the putative origin of the observed improvement in the photoactivity of the pyrite/marcasite mixture films.
LHI Journal of Land, Housing, and Urban Affairs, 2011
There was a plan to develop a low-carbon green village(approximately 400,000m 2) in A city, a new... more There was a plan to develop a low-carbon green village(approximately 400,000m 2) in A city, a new town. Restoration of water cycle is essential for creation of the low-carbon green village. Therefore, installation plan of LID-decentralized rainwater management facilities for natural water cycle was established for creation of the low-carbon green village. Analyses on effect of the water cycle were performed in conditions of before, after developing the low-carbon green village and after installing the LID facilities(rain garden, constructed wetland, rainwater harvesting facility, etc.) using SWMM-LID model developed by EPA. Due to the characteristic of permeable area before development and significant green spaces after development, installation plan of LID facilities to restore the water cycle did not show an obvious effect. However, potential of the hydrological cycle could be seen by the installation of the LID facilities.
We investigated oxygen defect states in SrTiO 3 (STO) thin films by using photoluminescence spect... more We investigated oxygen defect states in SrTiO 3 (STO) thin films by using photoluminescence spectroscopy and spectroscopic ellipsometry. The oxygen-deficient STO homoepitaxial films were fabricated by using different oxygen pressures and different oxygen flow rates for controlling the amount of oxygen vacancies systematically. The visible emission and absorption increased simultaneously with the increasing concentration of oxygen vacancies in the STO thin films. Given the absolute values of the optical constants, we discussed the origins of the visible absorption features in the STO thin films, in relation to the defect formation and related electronic reconstruction.
We investigated the high-energy electronic structure of a 5d perovskite SrHfO 3 by using optical ... more We investigated the high-energy electronic structure of a 5d perovskite SrHfO 3 by using optical spectroscopy and O 1s x-ray absorption spectroscopy. From the combined spectra the values of electronic structure parameters are estimated properly. In particular, the crystal field splitting energy, which is closely associated with the p-d hybridization strength, is as high as ∼5 eV, and the Sr 4d bands appear to be strongly mixed with the Hf 5d bands. These findings are discussed in relation to a possible ferroelectric instability in SrHfO 3 , and are compared with electronic properties of similar compounds, 3d SrTiO 3 and 4d SrZrO 3 .
With performing time-resolved pump-probe experiments using femtosecond optical pulses, we investi... more With performing time-resolved pump-probe experiments using femtosecond optical pulses, we investigate temperature dependent transition of the structural phase in single crystalline (SC) VO2 plates and polycrystalline films. Analysis of coherent optical phonons with the temperature change has revealed the M1-M2 transition within the insulating phase of the SC VO2. In stark contrast, no evidence on the M2 phase was found in a VO2 film composed of multi-grains. The results demonstrate that the strain is an important parameter in the structural transitions of VO2, which determines not only the appearance of the intermediate M2 phase but also the transition temperatures.
We report that visible emissions in the 4d/5d band insulators SrZrO3 and SrHfO3 can be induced by... more We report that visible emissions in the 4d/5d band insulators SrZrO3 and SrHfO3 can be induced by using the Cu-ion implantation technique. A sizable emission near 400 nm was observed clearly in both implanted samples. The intensity of this violet emission depended strongly on the photoexcitation energy. Our results were compared with the emission property of the Cu-ion-doped samples synthesized by using the solid state reaction method.
We investigated the effect of the chemical doping on the visible emission of the Cu-ion-doped per... more We investigated the effect of the chemical doping on the visible emission of the Cu-ion-doped perovskite zirconates. We synthesized the Cu-ion-doped Sr1−xCaxZrO3 (SCZO:Cu) compounds (x = 0 − 1), where the structural distortion and the chemical disorder were tuned due to the ionic size difference between Sr2+ and Ca2+. The nominal doping concentration of Cu ion was chosen to be 1%. We found that the visible emission in SCZO:Cu was suppressed dramatically with the substitution of Ca2+ for Sr2+ (x > 0). The violet emission was more susceptible to the structural distortion than the orange and the green emissions. These experimental findings were discussed in relation to the electronic properties of SCZO:Cu.
400 °C is optimal sulfurization temperature for pure pyrite FeS2 thin film, expecting better perf... more 400 °C is optimal sulfurization temperature for pure pyrite FeS2 thin film, expecting better performance as light-absorber.
Ocular immune privilege is maintained by constitutive expression of inhibitory molecules such as ... more Ocular immune privilege is maintained by constitutive expression of inhibitory molecules such as TGF-b, FAS and FAS-ligand. Here, we describe a model of immune privilege for the eye based on IL-27-induced suppression of Th17 responses. We show that Th17 cells are elevated in retina of mice during experimental autoimmune uveoretinitis (EAU) and treatment with anti-IL17 Abs reduces EAU severity. It is of note that the increase and subsequent trafficking of Th17 cells into the retina during EAU is accompanied by corresponding increases in IL-27 and IFN? in the retina. We further show that IL-27 is constitutively expressed in human or mouse retina and that IFN? upregulates its expression in retinal cells. Of particular interest is inhibition of the proliferation of uveitogenic Th17 cells by IL-27, suggesting that IFN? may mitigate uveitis by antagonizing Th17 expansion through induction of IL-27 in the target tissue. In a co-culture system the expansion of Th17 cells (propagated under T...
This study was carried out of investigate the effect of weed control methods on the growth of 'ca... more This study was carried out of investigate the effect of weed control methods on the growth of 'campbell early' grape at the vineyards which was divided into the 18 zone (3.5 m × 5.5 m/zone) in the grape research institute. It's investigated control effects, growth and quantity of grape and dominant weed of July~August by sprayed glufosinate ammonium and paraquat dichloride each 3 times, fabric covering, grass planting (Festuca myuros), mechanical weeding (3 times). The weed showed total of 16 species at the vineyards. Late-May to early growth stage of grape was dominated Chenopodium album and Trifolium repens, but to late growth stage of grape from mid-July was dominated Erigeron canadensis, Echinochloa crus-galli and Chenopodium album. Weed control effect of 10 day after treatment showed fabric covering 100%, grass planting (Festuca myuros L.) 95.3%, mechanical weeding 81.9%, glufosinate ammonium (3 times) 98.1% and paraquat dichloride (3 times) 90.4%, respectively. Growth of grape was higher herbicides treatment and mechanical weeding than others. Yield tended to be higher glufosinate ammonium (3 times) and paraquat dichloride (3 times) each 12.6 kg/tree, 12.3 kg/tree than others.
Ocular infection of Herpes Simplex Virus-I (HSV-1) causes Herpetic Stromal Keratitis (HSK), which... more Ocular infection of Herpes Simplex Virus-I (HSV-1) causes Herpetic Stromal Keratitis (HSK), which is a leading cause of infectious blindness. Although complex interactions of molecular and cellular events involve in the development of HSK, it has been known that angiogenesis is a key step for the HSK pathogenesis. Treatment of neutralizing antibody against vascular endothelial ° growth factor (VEGF) to inhibit VEGF activity reduced angiogenesis and HSK severity caused by infection of HSV-1 in mouse eyes. In addition, inactivation of cytokine which induces VEGF production and angiogenesis also reduced angiogenesis and HSK severity. Therefore, it has been proposed that VEGF or molecules which induce VEGF production or angiogenesis can be good target molecules for treating HSK. In this study, we investigated whether targeting VEGF or IL-1 receptor type I (IL-lRI) using RNAi technology could reduce angiogenesis in mouse eyes. A general introduction and overview of RNAi were provided in ...
A computer program written in the VPython language on the Glow Script platform is developed with ... more A computer program written in the VPython language on the Glow Script platform is developed with a view to aiding the study of vibrations and the waves. It simulates the forced motions of coupled oscillators of arbitrarily large number. Understanding the harmonic oscillations of physical systems underlies the core curriculum of college physics. It normally starts with the simple harmonic oscillation of a single oscillator and, afterwards, adds damping and external harmonic forcing. More than one coupled oscillators are, then, introduced and they give ways for understanding waves in continuous media as the number of oscillators becomes large. The reported product visualizes the motions of coupled oscillators and enhance the comprehension of such concepts as the normal modes of vibration and stationary waves.
Enhanced expression of integrin a v b 3 is commonly used as a biomarker for angiogenesis, which i... more Enhanced expression of integrin a v b 3 is commonly used as a biomarker for angiogenesis, which is one of the key pathophysiologic processes in cerebral infarct. Integrin a v b 3 can be imaged with arginine-glycine-aspartic acid (RGD) peptide agents. In this study, characteristics of positron emission tomography (PET) using a 68 Ga-labeled RGD were investigated in pediatric cerebral infarct. Pediatric patients with moyamoya disease underwent 68 Ga-RGD PET in a research protocol for neovascularization evaluation. In these patients, 17 cerebral infarct lesions of 10 patients were included in the analysis. On 68 Ga-RGD PET, the infarct lesion to contralateral brain ratio (LCR) of the infarct lesion was measured and analyzed with regard to postinfarct time interval (PTI) and perfusion single-photon emission computed tomography (SPECT) findings. An increase in 68 Ga-RGD uptake was observed in cerebral infarct, particularly in recent lesions. The LCR was significantly higher in the recent than in the chronic lesions, and a significant correlation existed between the LCR and PTI. Additionally, the LCR was significantly higher in the lesions with hyperperfusion on SPECT. This study, as the first human study using an RGD agent for in vivo cerebral infarct imaging, demonstrated that 68 Ga-RGD PET has a potential for molecular imaging of integrin a v b 3 expression in cerebral infarct as a biomarker of angiogenesis.
Journal of the Korean Society of Hazard Mitigation, 2018
Colombia has experienced many problems in its urban areas due to increase in population in these ... more Colombia has experienced many problems in its urban areas due to increase in population in these areas. In particular, because of recurring slope disasters in urban areas, it has become necessary for the Colombian government to analyze these hazards. In this study, we selected a test bed with a high-potential source area in the small and medium city and conducted the physical vulnerability assessment of the test bed. First, we collected and analyzed the causal factors and landslide inventory. Using the landslide inventory and spatial information database, we performed a susceptibility assessment to identify high-potential landslide source areas. Next, we defined the parameters (travel angle, maximum velocity, etc.) for the Flow-R model analysis, which we used to calculate the propagation zone of debris flow. For the vulnerability assessment, we used road sections to define the boundary zones. Finally, we developed and evaluated the physical vulnerability map of Soacha using the propagation zones of debris flow and the boundary zones. The physical vulnerability assessment technique developed through this study will provide useful information for future urban planning and disaster prevention in Colombia.
The structural and electro-optical influence of marcasite on the properties of solution-processed... more The structural and electro-optical influence of marcasite on the properties of solution-processed iron pyrite thin films was investigated. Marcasite has a strong tendency to form simultaneously with pyrite upon sulfurization of amorphous iron-oxide precursor films, leading to a mixed-phase structure in which pyrite grains are surrounded by nanocrystalline marcasite boundaries. The optical analysis in combination with spectroscopic ellipsometry revealed that marcasite should have a bandgap of approximately 0.85-0.88 eV with a higher absorption coefficient than pyrite, differing strongly from the prior belief that marcasite has a bandgap of less than 0.4 eV. In addition, the pyrite/marcasite film has been found to have a larger diffusion coefficient for photogenerated minority carriers than the phase-pure pyrite film from electrochemical impedance analyses, resulting in a higher photocurrent density, as determined through photoelectrochemical measurement. The facile transport of a minority carrier along the marcasite boundaries is the putative origin of the observed improvement in the photoactivity of the pyrite/marcasite mixture films.
LHI Journal of Land, Housing, and Urban Affairs, 2011
There was a plan to develop a low-carbon green village(approximately 400,000m 2) in A city, a new... more There was a plan to develop a low-carbon green village(approximately 400,000m 2) in A city, a new town. Restoration of water cycle is essential for creation of the low-carbon green village. Therefore, installation plan of LID-decentralized rainwater management facilities for natural water cycle was established for creation of the low-carbon green village. Analyses on effect of the water cycle were performed in conditions of before, after developing the low-carbon green village and after installing the LID facilities(rain garden, constructed wetland, rainwater harvesting facility, etc.) using SWMM-LID model developed by EPA. Due to the characteristic of permeable area before development and significant green spaces after development, installation plan of LID facilities to restore the water cycle did not show an obvious effect. However, potential of the hydrological cycle could be seen by the installation of the LID facilities.
We investigated oxygen defect states in SrTiO 3 (STO) thin films by using photoluminescence spect... more We investigated oxygen defect states in SrTiO 3 (STO) thin films by using photoluminescence spectroscopy and spectroscopic ellipsometry. The oxygen-deficient STO homoepitaxial films were fabricated by using different oxygen pressures and different oxygen flow rates for controlling the amount of oxygen vacancies systematically. The visible emission and absorption increased simultaneously with the increasing concentration of oxygen vacancies in the STO thin films. Given the absolute values of the optical constants, we discussed the origins of the visible absorption features in the STO thin films, in relation to the defect formation and related electronic reconstruction.
We investigated the high-energy electronic structure of a 5d perovskite SrHfO 3 by using optical ... more We investigated the high-energy electronic structure of a 5d perovskite SrHfO 3 by using optical spectroscopy and O 1s x-ray absorption spectroscopy. From the combined spectra the values of electronic structure parameters are estimated properly. In particular, the crystal field splitting energy, which is closely associated with the p-d hybridization strength, is as high as ∼5 eV, and the Sr 4d bands appear to be strongly mixed with the Hf 5d bands. These findings are discussed in relation to a possible ferroelectric instability in SrHfO 3 , and are compared with electronic properties of similar compounds, 3d SrTiO 3 and 4d SrZrO 3 .
With performing time-resolved pump-probe experiments using femtosecond optical pulses, we investi... more With performing time-resolved pump-probe experiments using femtosecond optical pulses, we investigate temperature dependent transition of the structural phase in single crystalline (SC) VO2 plates and polycrystalline films. Analysis of coherent optical phonons with the temperature change has revealed the M1-M2 transition within the insulating phase of the SC VO2. In stark contrast, no evidence on the M2 phase was found in a VO2 film composed of multi-grains. The results demonstrate that the strain is an important parameter in the structural transitions of VO2, which determines not only the appearance of the intermediate M2 phase but also the transition temperatures.
We report that visible emissions in the 4d/5d band insulators SrZrO3 and SrHfO3 can be induced by... more We report that visible emissions in the 4d/5d band insulators SrZrO3 and SrHfO3 can be induced by using the Cu-ion implantation technique. A sizable emission near 400 nm was observed clearly in both implanted samples. The intensity of this violet emission depended strongly on the photoexcitation energy. Our results were compared with the emission property of the Cu-ion-doped samples synthesized by using the solid state reaction method.
We investigated the effect of the chemical doping on the visible emission of the Cu-ion-doped per... more We investigated the effect of the chemical doping on the visible emission of the Cu-ion-doped perovskite zirconates. We synthesized the Cu-ion-doped Sr1−xCaxZrO3 (SCZO:Cu) compounds (x = 0 − 1), where the structural distortion and the chemical disorder were tuned due to the ionic size difference between Sr2+ and Ca2+. The nominal doping concentration of Cu ion was chosen to be 1%. We found that the visible emission in SCZO:Cu was suppressed dramatically with the substitution of Ca2+ for Sr2+ (x > 0). The violet emission was more susceptible to the structural distortion than the orange and the green emissions. These experimental findings were discussed in relation to the electronic properties of SCZO:Cu.
400 °C is optimal sulfurization temperature for pure pyrite FeS2 thin film, expecting better perf... more 400 °C is optimal sulfurization temperature for pure pyrite FeS2 thin film, expecting better performance as light-absorber.
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Papers by Yunsang Lee