Association between localised retinal nerve fibre layer defects and cardiovascular risk factors

Localised retinal nerve fibre layer defects (RNFLDs) are reported to indicate the degree of glaucomatous damage but can also be sequelae of retinal vascular insufficiency as a result of systemic vascular factors. We investigated the association between RNFLDs and cardiovascular risk factors. RNFLDs were detected in 440 (29.2%) of 1508 subjects. The presence of RNFLDs was associated with higher HbA1c (odds ratio [OR] 1.289, p < 0.001), higher 24-h mean systolic blood pressure (SBP; OR 1.013, p < 0.005), and lower estimated glomerular filtration rate (eGFR; OR 0.995, p < 0.005). An increasing number of RNFLDs was correlated with higher SBP (r = 0.186, p < 0.001), higher HbA1c (r = 0.128, p < 0.010), lower eGFR (r = -0.112, p < 0.020), and younger age (r = -0.303, p < 0.001). Subjects with RNFLDs had a higher predicted 10-year risk of atherosclerotic cardiovascular disease than did those without RNFLDs (9.7% vs 7.9%, p = 0.008 in middle-aged subjects, 25.6% vs 23.2%, p = 0.040 in older subjects). In conclusion, RNFLDs are associated with SBP, eGFR, and HbA1c. Concomitant cardiovascular risk factors should be considered when evaluating patients with localised RNFLDs.ope

넓은 밴드갭 반도체인 BaSnO3의 이동성 향상에 관한 연구

학위논문 (박사)-- 서울대학교 대학원 : 자연과학대학 물리·천문학부, 2018. 2. 차국린.Wide bandgap semiconductors have received much attention for their potential applications in high-temperature and high-power electronics. Apart from typical wide bandgap semiconductors, e.g. SiC and GaN, there has been a growing interest in perovskite oxide BaSnO3, which is studied especially for transparent conducting oxides and transparent oxide semiconductors in transparent electronics, to date. In usual active devices in display, the transport property, e.g. mobility, is less important compared to its transparency because the reaction of human eye is slow compared to the speed of digital processing. On the other hand, BaSnO3 has a high mobility, which records the highest value among wide bandgap semiconductors in the degenerate doped regime, so that the study for enhancement of its mobility combined into devices is surely needed toward its application in high-temperature and high frequency area, not only constrained in transparent electronics. Another particular advantages using BaSnO3-based electronics is the development of all epitaxial heterostructures, that is, incorporating of perovskite oxides with large polarization, ferroelectricity, ferromagnetism and multiferroicity. This enables application toward non-volatile switching memory and spintronics, which give the opportunity for extending the amount and type of information in electronics. This dissertation focuses on the study of mobility enhancement of BaSnO3 in three aspects such as the excellent transport on MgO substrate, bandgap engineering by Hf doping for the possibility of modulation doped heterostructure, and modulation doped-polar interface by LaInO3/undoped BaSnO3/La-doped BaSnO3 heterostructures. All the epitaxial films are grown by using the pulsed laser deposition technique. And the crystallinity of films is investigated by X-ray diffraction analysissingle phase growth, well defined orientation. The transmission electron spectroscopy has been employed to study the microstructural property of crystalline BaSnO3 films such as misfit dislocations and threading dislocations. The transport property of films, e. g. resistivity, mobility, carrier concentration, was measured by Van der Pauw method and all the devices has a three terminal-field effect transistor structures with metal-insulator-semiconductor interfaces. Because the research of BaSnO3 is limited on films on perovskite oxide substrates such as SrTiO3, SmScO3, PrScO3, LaAlO3, and BaSnO3, which suffer from a small size, a small bandgap and oxygen instability, the effort to grow BaSnO3 films with excellent transport property on non-perovskite MgO substrate is very important toward wafer scale processing with oxygen stability. This opens commercially the area of BaSnO3-based electronics, too. In spite of non-perovskite oxide substrate, the maximum electron mobility of La-doped BaSnO3 films is 97.2 cm2/Vs, which is quite comparable value deposited on BaSnO3 single crystal substrate. And the field effect transistor with HfO2 dielectrics reveals successful carrier modulation of La-doped BaSnO3 channel with mobility of 43.9 cm2/Vs and on-off ratio of 3.0ⅹ107, which is slightly better compared to devices on SrTiO3 substrate. Another possibility to enhance mobility of devices based on BaSnO3 channel is modulation doping like GaAs system. The carrier modulation of BaSnO3 by field effect is limited in metal-insulator-semiconductor structure, to date. So intentional La doping or unintentional oxygen vacancies, source of electron carriers, may degrade the device performance. On the other hand, heterostructures with interfaces of doped large bandgap material and channel can increase mobility by reducing ionized impurity scattering. To employ this modulation doping in BaSnO3-based heterostructures, bandgap engineering is a necessary step. So, Hf substation for Sn in BaSnO3 is investigated, which significantly modifies the band structure, crystal structure, and the bandgap. Also La doping in BaSn1-xHfxO3 is investigated, displaying significant potentials for modulation doping in BaSnO3/BaSn1-xHfxO3 heterostructures. Lastly, enhancement of mobility of BaSnO3 in polar interface has been studied. The optimal condition of semiconductor devices is switching with low-on-state resistance. To manipulate highly conductive current, high sheet carrier concentration and high mobility is needed in field-induced confined well. Polarization doping helps to accumulate high density of mobile charges, which is impossible in usual solid-gate-dielectrics. Recently, conducting interface between LaInO3/La-doped BaSnO3 was reported with high sheet carrier density in the order of 1013 cm-2. Moreover, if the mobility of channel in this polar interface is enhanced, the two dimensional electron gas science in BaSnO3-based electronics will be more powerful. Because the slight La doping on BaSnO3 channel is needed to accumulate high carrier density, modulation doping technique is applied in smaller bandgap BaSnO3 compared to LaInO3 by inserting undoped BaSnO3 spacer layer between La-doped BaSnO3 and LaInO3. The enhanced mobility of this modulation doped-polar interface may lead further advance of LaInO3/BaSnO3 polar interface in high mobility and high power electronics applications.Abstract 1 Contents 5 List of Figures 8 List of Tables 12 1. Introduction 13 1.1 Advantages of BaSnO3 materials 15 1.1.1 Wide bandgap 15 1.1.2 Thermal stability 18 1.1.3 High mobility 20 1.1.4 All epitaxial heterostructures with multiple functionalities 23 1.1.5 Optoelectronics 25 1.2 Previous study on BaSnO3 26 1.2.1 The transport property of films 26 1.2.2 The transport property of devices 28 2. Growth of thin films and FET devices by pulsed laser deposition 32 2.1 Target preparation 33 2.2 Pulsed laser deposition 34 2.3 Fluence and distance dependence and target tracks 35 2.4 Mask effect 37 3. High mobility BaSnO3 films and field effect transistors on non-perovskite MgO substrate 39 3.1 The material properties of MgO 40 3.1.1 MgO substrate for experiment 41 3.1.2 Benefit at annealing experiment in high temperature 42 3.2 Structure property of BSO in MgO substrate 44 3.2.1 X-ray diffraction analysis 44 3.2.2 Transmission electron microscopy 45 3.3 Transport property of BLSO film on MgO substrate 47 3.3.1 Buffer effect 47 3.3.2 La doping dependence 49 3.3.3 Trapped electrons in TDs and further strategy 50 3.4 Field effect transistor based on BLSO channel on MgO substrate 52 3.4.1 FET fabrication process 52 3.4.2 Theory for metal-insulator-semiconductor FET 53 3.4.3 FET based on BLSO channel on MgO substrate 55 4. Bandgap engineering of BaSnO3 by Hf doping 58 4.1 BaSnO3 vs. BaHfO3 60 4.2 Density functional theory calculation of BaSn1-xHfxO3 61 4.3 Structure property of BaSn1-xHfxO3 films 63 4.4 Optical property of BaSn1-xHfxO3 films 65 4.4.1 Bandgap energy of BaSn1-xHfxO3 films grown on MgO substrate 65 4.4.2 Bandgap bowing 67 4.5 Transport property of n-type (Ba,La)(Sn,Hf)O3 films 68 4.6 Possibility for enhancement of mobility by (Ba,La)(Sn,Hf)O3/BaSnO3 interface 72 5. Modulation doping in LaInO3/BaSnO3 polar interface 73 5.1 Various 2DEG 74 5.2 Scattering mechanisms of 2DEG 76 5.2.1 Coulomb scattering 78 5.2.2 Phonon scattering 80 5.2.3 Interface roughness scattering and alloy disorder scattering 80 5.3 Polar interface 81 5.3.1 Mechanisms and limitation of LaAlO3/SrTiO3 interface 82 5.3.2 Mechanism and advantages of LaInO3/BaSnO3 interface 84 5.4 Modulation doping in LaInO3/BaSnO3 polar interface (LIO/BSO/BLSO) 87 5.4.1 Hall measurement (LIO/BSO/BLSO interface) 87 5.4.2 Self-consistent 1D Poisson-Schrodinger calculation 91 5.4.3 Field effect transistor based on LIO/BSO/BLSO interface 95 5.4.4 Remark on LIO/BSO polar interface 101 6. SrSn1-xRuxO3 and BaSn1-xRuxO3 system (p-type possibility) 105 6.1 SrSn1-xRuxO3 (x: 0.1~0.3) 106 6.2 BaSn1-xRuxO3 (x: 0.1~0.3) 109 6.3 Half metallic state (SrRu1-xSnxO3, x~0.1) and dilute magnetic semiconductor (SrSn1-xRuxO3, x~0.3) 113 Bibliography 115 List of publications and presentations 130 Abstract (in Korean) 132Docto

Association of Keratin 8 Level in Aqueous Humor With Outcomes of Intravitreal Ranibizumab Treatment for Neovascular Age-Related Macular Degeneration

Purpose: To investigate keratin 8 (KRT8) level in the aqueous humor (AH) of patients with neovascular age-related macular degeneration (nAMD) and elucidate its association with intravitreal ranibizumab (IVR) treatment outcomes. Methods: This prospective study involved 58 eyes of treatment-naïve nAMD patients treated with three IVR doses monthly and whose AH samples were collected at baseline and two months after the initial treatment. KRT8 level was determined using the enzyme-linked immunosorbent assay and compared with that of the control group, which comprised patients who underwent cataract surgery during the same period. The nAMD-affected eyes were classified into responder (dry) and poor responder (persistent fluid) groups, according to optical coherence tomography (OCT) findings at month three. Additionally, associations between the KRT8 level and IVR treatment outcomes were analyzed. Results: The baseline KRT8 level was significantly higher in the AMD group than in the control group. In the AMD group, responders demonstrated significant differences between the KRT8 level at the baseline and month two, whereas poor responders exhibited no significant change. Regression analysis revealed that a higher KRT8 level at month two was significantly associated with persistent fluid upon OCT at months three and six. Conclusions: Monitoring aqueous KRT8 level may facilitate early determination of the therapeutic effects of IVR in nAMD patients and reflect the conditions of retinal pigment epithelium during the disease course. Translational relevance: Monitoring aqueous KRT8 may aid early determination of therapeutic effects of IVR in neovascular AMD patients and reflect the health conditions of retinal pigment epithelium.ope

Impact of statin treatment on cardiovascular events in patients with retinal vein occlusion: a nested case-control study in Korea

Objectives: Retinal vein occlusion (RVO) is associated with an increased risk of future cardiovascular events. Statin therapy is a key cornerstone in prevention for patients at high cardiovascular risk. However, little is known about the role of statin therapy for patients with RVO. This study evaluated whether statin treatment in patients with RVO was associated with a lower risk of cardiovascular events. Methods: A population-based, nested case-control study was conducted with a cohort of newly diagnosed RVO patients without prior cardiovascular disease between 2008 and 2020 using a nationwide health claims database in Korea. From this cohort of RVO patients, we identified cases of cardiovascular events (stroke or myocardial infarction) after RVO and matched controls based on sex, age, insurance type, antiplatelet use, and underlying comorbidities using 1:2 incidence density sampling. Results: Using a cohort of 142,759 patients with newly diagnosed RVO, we selected 6,810 cases and 13,620 matched controls. A significantly lower risk of cardiovascular events (adjusted odds ratio, 0.604; 95% confidence interval, 0.557 to 0.655) was observed in RVO patients with statin treatment than in those without statin treatment. Statin treatment was associated with a reduced risk for both stroke and myocardial infarction after RVO. Longer statin treatment after RVO was associated with a lower risk for cardiovascular events. Conclusions: Statin treatment was associated with a lower risk for future cardiovascular events in patients with newly diagnosed RVO. Further studies are warranted to clarify the potential cardiovascular preventive role of statins in patients with RVO.ope

Comparison of Preoperative and Postoperative Ocular Biometry in Eyes with Phakic Intraocular Lens Implantations

PURPOSE: To compare preoperative and postoperative ocular biometry in patients with iris-fixated phakic intraocular lens (pIOLs): Artisan and Artiflex. MATERIALS AND METHODS: This study included 40 eyes with Artisan and 36 eyes with Artiflex pIOL implants. Anterior chamber depth (ACD) and axial length (AL) were measured by applanation ultrasonography (A-scan) and partial coherence interferometry (IOLMaster) preoperatively and 3 months after pIOL implantation. RESULTS: ACD measurements after Artisan or Artiflex pIOL implantation were smaller than preoperative measurements. Specifically, the difference after Artisan pIOL implantation was -1.07 ± 0.17 mm by A-scan and -0.08 ± 0.08 mm by IOLMaster. The difference after Artiflex pIOL implantation was -1.31 ± 0.15 mm by A-scan and -0.05 ± 0.07 mm by IOLMaster. After Artisan pIOL implantation, differences in AL measurements by A-scan were insignificant (difference: -0.03 ± 0.15 mm), whereas postoperative AL measurements by IOLMaster were significantly longer than preoperative measurements (difference: 0.12 ± 0.07 mm). After Artiflex pIOL implantation, AL measurements by both A-scan and IOLMaster were significantly longer than preoperative measurements (difference: 0.09 ± 0.16 mm by A-scan and 0.07 ± 0.10 mm by IOLMaster). In the Artiflex group, differences in AL measurements by A-scan correlated with the central thickness of the Artiflex pIOL. CONCLUSION: ACD and AL measurements were influenced by iris-fixated phakic IOL implantation.ope

Changes in retinal microvasculature and retinal layer thickness in association with apolipoprotein E genotype in Alzheimer's disease

Biomarker tests of Alzheimer's disease (AD) are invasive and expensive. Recent developments in optical coherence tomography (OCT) and OCT angiography (OCTA) have enabled noninvasive, cost-effective characterization of retinal layer vasculature and thickness. Using OCTA and OCT, we characterized retinal microvascular changes in the mild cognitive impairment (MCI) stage of AD and assessed their correlation with structural changes in each retinal neuronal layer. We also evaluated the effect of the APOE-ε4 genotype on retinal microvasculature and layer thickness. Retinal layer thickness did not differ between MCI patients (40 eyes) and controls (37 eyes, all p > 0.05). MCI patients had lower vessel density (VD) (p = 0.003) of the superficial capillary plexus (SCP) and larger foveal avascular zone area (p = 0.01) of the deep capillary plexus (DCP) than those of controls. VD of the SCP correlated with the ganglion cell layer (r = 0.358, p = 0.03) and inner plexiform layer thickness (r = 0.437, p = 0.007) in MCI patients. APOE-ε4-carrying MCI patients had a lower VD of the DCP than non-carriers (p = 0.03). In conclusion, retinal microvasculature was reduced in patients with AD-associated MCI, but retinal thickness was not changed; these changes might be affected by the APOE genotype. OCTA of the retinal microvasculature may be useful to detect vascular changes in AD.ope

방송매체를 통한 국악 교육의 활성화 방안 연구

이 연구는 현재 학교교육만으로는 부족한 국악교육을 방송매체를 통해서 더욱 활성화시킬 수 있는 방안을 모색하는데 그 목적을 두었다. 이 연구에서는 먼저 국악교육의 필요성을 강조하였으며, 현행 중학교 음악과 제6차 교육과정과 2000년대부터 시행될 제7차 교육과정을 중심으로 교육현장에서의 국악교육 실태를 파악하였다. 다음으로 방송매체가 학생들에게 미치는 영향력 분석과 방송매체와 교육과의 관계, 방송매체의 음악교육적 기능 등을 연구하였다. 이 연구에서 분석한 현행 제6차 중학교 음악과 교육과정과 제7차 교육과정의 결과 중학교 교육현장에서의 국악교육은 국악의 내용면에서 서양음악에 비해 그 비중도 매우 낮게 나타났다. 그 이유는 학생들과 학부모들의 국악에 대한 무관심, 교과서 내의 국악내용의 문제, 교사의 국악지도 능력 부족 그리고 국악수업을 위한 수업 교자재(악기)의 부족 등을 내세울 수 있다. 그러므로 이 연구에서는 학교교육 현장에서의 실시되고있는 국악교육의 문제점을 방송매체를 통하여 이를 국악교육에 효과적으로 활용하는 방안을 모색해 보았다. 이에 따른 연구 방법으로는 우리나라의 대표적인 방송3사인 KBS, MBC, SBS와 EBS 교육방송의 정규 국악프로그램의 현황(1998.3~현재)을 근거 자료로 삼아 국악방송의 양(量)적인 문제, 국악방송의 시간대 문제, 국악방송의 내용과 질(質)적인 문제, 그리고 국악의 여러장르를 이해할 수 있는 내용의 다양성 문제 등에 관하여 조사하고 이를 분석하였다. 이 결과, 나타난 문제점들과 그에 대한 개선책을 제시하면 다음과 같다. 첫째, 국악방송 프로그램의 종류나 방송시간이 다른 음악 장르에 비하여 절대적으로 그 수치가 낮다는 점이다. 조사결과 학생들은 물론, 우리 국민들에게 다양한 음악을 들려주어 건전하고 건강한 음악 문화를 형성하기 위해서라도 프로그램의 수나 방송시간(量)을 증가시켜야 될 것이다. 둘째, 국악방송의 전체적인 시간대가 너무 이른 새벽이라던 지, 늦은 밤에 방송되는 것이 대부분이다. 이것은 마치 각 방송사가 국악방송을 하고있다는 명분만 앞세우는 듯한 인상이 짙다. 앞으로는 가족 전체가 우리 음악을 통해서 우리 음악에 대한 애정을 느끼도록 시간대의 조절이 고려되어야 할 것이다. 셋째, 어떤 국악프로그램의 경우 지나치게 시청률을 의식한 나머지 흥미 위주로만 프로그램을 구성하는 경우도 있다. 이것은 전통 연주 방식에 대한 실험적인 성격을 띄고는 있으나, 기존의 전통양식을 배제한 체 새로운 양식만을 앞세움으로 우리나라 전통음악의 품위를 손상시킬 위험도 내포되어 있다. 또한 판소리, 민요, 사물놀이 등 국악의 지엽(枝葉)적인 분야만을 고집 하는 사례가 보이고 있는데, 이는 국악의 장르가 다양하다고 하는 점을 인식시키는데 있어서 걸림돌이 된다고 하겠다. 그러므로 앞으로의 국악방송은 프로그램 선정에 보다 신중을 기해야 되리라 믿는다. 끝으로 프로그램을 제작하는 제작진들의 국악에 대한 일반적인 상식과 또는 전문가들의 조언이나 자문을 필요로 하는 부분을 지적하고 싶다. 간혹 “새롭게”라는 미명하에 전통을 왜곡시키는 사례도 보이고 있기 때문이다. 그러므로 이 연구에서는 현재 국악방송 프로그램의 위와같은 문제점을 지적하고 이에따른 새로운 국악방송 프로그램을 제안하고자 한다. ; This study has a purpose to grope for a plan that can activate Korean traditional music education, which is not good enough with school education, through the mass communication. It emphasizes the necessity of Korean traditional music and studies the present situation of Korean music education in junior high school, focusing on the 6th curriculum revision and the 7th curriculum revision which come into force on and after the year 2000. Also, this study has the influence analysis of the mass communication to student, the relation to the mass communication and education, and the educational function of the mass communication in music. As a result of analyzing the 6th of present music curriculum in middle school and the 7th of music curriculum, the contents of the present situation of Korean traditional music education in junior high school is low compared with Western music. This is result in the aspect of a teacher s teaching ability and in the facility of Korean traditional music has lower standard than that of the ministry of education. Therefore, this study gropes for using the music educational function of the mass communication as a way of educational supplementing the lacing part of Korean traditional music education in school education. This study is researched and analyzed problems of Korean traditional music broadcasting, the broadcasting time of Korean traditional music, the contents and quality of Korean traditional mass communication music, and the variety of contents that can make understand the several genres of Korean traditional music on the basis of the present situation of regular Korean traditional music programs(Mar. 1998~now)in Korean representative broadcasting studies KBS, MBC, SBS, and EBS. As a result, problems and improving plans are as follows. First, the number of Korean traditional music programs or the amount of its broadcasting time is absolutely low compared with other genres of music. There should be more programs or broadcasting time to form music culture by playing various music to the public as well as students. Second, the time zone of Korean traditional music broadcasting is mostly early in the morning or late at night. This gives on impression that each broadcasting system broadcasts Korean traditional music programs just for justifying itself. In the future, the broadcasting time of Korean traditional music should be modified so that all the family can have affection toward Korean traditional music. Third, certain program is composed only of items of entertainment to gain a better rating. In a case like this can damage the quality of our traditional music. Also, the programs mainly focuse on only certain parts of Korean traditional music in including Pansori, Folk song and Samulnori, and this can be an obstacle in understanding that Korean traditional music genre varies. Therefore, the future Korean traditional music programs should be selected more carefully. Finally, producers of Korean traditional music programs should have common sense on Korean traditional music and they need an expert s advice. More often than not, some examples show the distortion of tradition under the name of new . Therefore, this study proposes how improve Korean traditional music programs.논문개요 = ⅴ Ⅰ. 서 론 = 1 A. 연구의 필요성 및 목적 = 1 B. 연구의 내용 및 방법 = 2 C. 연구의 제한점 = 3 Ⅱ. 본 론 = 5 A. 국악교육의 필요성 = 5 B. 방송매체의 특성 및 기능 = 8 C. 중학교 음악과 교육과정 = 17 D. 1930년대 후반의 방송 = 29 E. 우리나라의 방송편성 기준 = 34 F. 외국 전통음악 방송의 현황 = 36 G. 우리나라 국악방송의 현황 = 38 H. 국악방송의 문제점 및 방송시안 = 58 Ⅲ. 결론 및 제언 = 63 A. 결론 = 63 B. 제언 = 65 참고문헌 = 67 ABSTRACT = 7

Development of Novel Ionic Nano-Hybrid Materials and Multi-functional Ionic Composites for Chemical and Electrochemical Catalysis

In this dissertation researches, three different topics were investigated. In Chapter I, ionic liquid-carbon nanotube (IL-CNT) hybrid materials were utilized as a support material for metal nanoparticles, and applied the supported metal nanoparticles to the hydrogenation of olefins and the electrochemical oxygen reduction reaction, which is crucial in fuel cell development. In Chapter II, the ionic liquid-silica or magnetic nanoparticle hybrid materials were used to immobilize palladium nanoparticles. In Chapter III, a multi-function catalyst system, composed of Pd/Sc(OTf)3/ionic liquid, has been developed for tandem one-pot conversion of phenol to ε-caprolactam. In chapter I, the imidazolium moiety having hydrophilic Br anion was covalently bonded with multi-walled carbon nanotubes (MWCNTs). The imidazolium salt-functionalized ionic CNTs were easily dispersed in water, which made possible to deposite Pd nanoparticle onto the ionic CNTs under mild condition (1 atm H2, room temperature) to afford Pd/IL-f-MWCNTs. Direct anion-exchange of the hydrophilic Br anion with SbF6 afforded the hydrophobic Pd/IL(SbF6)-f-MWCNTs, which preferentially dispersed in ionic liquids and i-PrOH. A combination of the Pd/IL-f-MWCNTs having SbF6 anion with an [bmim][SbF6] could be reused up to 50 times, demonstrating the supported palladium nanoparticles onto ionic CNTs could be a new robust recyclable ionic liquid-based catalytic system. In order to investigate the effects of anion on electrocatalytic activity of the Pd nanoparticles supported onto ionic CNTs, the MWCNT-surfaces were modified with polymeric imidazolium salt having different anions. The Pd nanoparticles were also easily deposited onto the ionic MWCNTs, modified with polymeric imidazolium salt, to afford the Pd/PolyIL(X)-CNT, (X = Cl, Br, I, ClO4, BF4, PF6). The electrocatalytic activity of these supported palladium nanoparticle catalysts was investigated for oxygen reduction reaction (ORR). It was found that the anions of imidazolium moiety significantly impacted on the ORR kinetics in 0.1 M HClO4 solution. The order of the ORR kinetic activity of the supported Pd/PolyIL(X)-CNT (X: Cl &amp;gt; ClO4 &amp;gt; BF4 &amp;gt; Br ≈ PF6 &amp;gt;&amp;gt; I) indicates that subtly varied structure of ionic liquid moiety profoundly influence the performance of the supported Pd nanoparticle catalysts onto ionic MWCNTs, and molecular-level control of interfacial interactions between the support material, catalysts, and electrolytes is important in the design of supported metal nanoparticle catalysts for fuel cells. It has been also developed a new-type of zwitterionic MWCNTs, which were functionalized covalently with zwitterionic poly(imidazolium sulfonate), with which the pre-synthesized gold nanoparticles, coated with sodium citrates, were assembled with high density onto multi-walled carbon nanotubes. The high-density assembly of the Au nanoparticles onto the zwitterionic MWCNTs ascribe to the electrostatic interactions between zwitterionic imidazolium moiety and citrates stabilizer. The AuNP/zwitterionic CNT hybrids exhibited excellent electrocatalytic activity in oxygen reduction reaction (ORR). In order to elucidate the origin of positive effects of imidazolium salt on electrocatalytic activity, the metal-free electrocatalytic activities of the imidazolium salt-functionalized ionic multi-walled carbon nanotubes (IM-f-MWCNTs) in the oxygen reduction reaction (ORR) have also been investigated. The zwitterionic poly(imidazoliumsulfonate)-functionalized MWCNTs exhibited remarkable electrocatalytic activity and the showed better fuel selectivity than the commercial Pt/C electrocatalyst. In chapter II, ionic liquid composed of imidazolium chloride and urea moiety was combined with spherical silica nanoparticle to immobilize the Pd nanoparticles. The supported palladium nanoparticle catalysts can be recovered and reused several times without loss of catalytic activity in Suzuki-Miyaura coupling reaction. The palladium nanoparticles also immobilized onto the silica-coated magnetic particle. The supported palladium nanaoparticle catalysts showed excellent catalytic activity for the hydrogenation of olefins in ionic liquid. The catalyst could easily be separated by using magnet. In chapter III, a multi-function catalyst system, composed Pd-Sc(OTf)3-[bmim][PF6], was developed for tandem one-pot conversion of phenol to ε-caprolactam in 67% overall yield. Pd and Sc(OTf)3 selectively cooperated to catalyze the hydrogenation of phenol to cyclohexanone with excellent conversion (&amp;gt;99.9%) and selectivity (99.9%) within 2 h. Whereas Sc(OTf)3 and [bmim][PF6] cooperated to catalyze the tandem transformation of the resulting cyclohexanone to cyclohexanone oxime and Beckmann rearrangement, affording caprolactam. ;본 연구는 화학적, 전기화학적 촉매반응에 응용하기 위하여 이미다졸염으로 구성된 이온성 액체-나노소재가 융합된 촉매 시스템과, 복합적 기능을 가진 이온성 촉매 시스템에 관한 연구이다. 제 1장에서는 친수성인 Br 이온을 가지는 이미다졸염을 다중벽탄소나노튜브에 공유결합으로 결합시켰다. 이렇게 합성된 탄소나노튜브는 친수성 성질을 가지게 되어 물에 잘 분산되고 팔라듐 나노입자를 온화한 조건에서 균일하게 고정시킬 수 있게 된다. (수소기체 1기압, 상온조건). 팔라듐이 고정된 촉매를 물에서 음이온 교환반응을 통해 소수성을 띠는 SbF6 음이온을 가지는 촉매로 합성한 뒤, 같은 음이온을 가지는 [bmim][SbF6] 이온성 액체와 isopropanol로 이루어진 혼합 용매에서 수소화반응을 진행하였으며, 50번이상의 재사용이 가능함을 확인할 수 있었다. 이 결과를 바탕으로 이미다졸염으로 이루어 졌으나 각기 다른 음이온을 지니는 폴리머를 다중벽 탄소나노튜브에 공유결합으로 결합시켜 팔라듐 나노입자를 온화한 조건에서 고정시켜서 6가지의 서로다른 음이온을 지니는 팔라듐-이온성 폴리머 탄소나노튜브 촉매를 합성하였다. 이 촉매를 이용하여 0.1 M HClO4 수용액 조건에서 산소환원반응에서의 음이온에 따른 촉매 활성을 조사한 결과 Cl &amp;gt; ClO4 &amp;gt; BF4 &amp;gt; Br ≈ PF6 &amp;gt;&amp;gt; I 음이온 순서로 나타나게 되었으며 이 결과는 이온성 액체의 음이온의 변화가 전체 이온성 탄소나노튜브의 반응성의 차이를 야기하며, 연료전지 내의 지지체, 촉매, 전해질 사이에서 이루어지는 분자수준에서의 변화조건이 중요하다는 것을 말해주고 있다. 또한 짝이온성을 지니는 이온성 폴리머(polyimidazolium sulfonate)를 탄소나노튜브와 공유결합으로 결합시킨 후, 짝이온성 폴리머 표면에 금 나노입자를 고밀도로 균일하게 고정시킬 수 있었으며 이 촉매 역시 산소환원반응에서 좋은 촉매활성을 나타내었다. 또한 이미다졸염이 전기화학적 산소환원반응에 미치는 근원적인 이유를 알아보기 위해 금속 나노입자 없이 산소환원반응을 진행한 결과 poly imidazoliumsulfonate가 결합된 탄소나노튜브촉매가 비교적 좋은 촉매활성을 나타내었고 특히 메탄올 선별성에서는 상용화 되고 있는 백금촉매보다 뛰어난 연료 선별성을 나타내었다. 제 2장에서는 imidazolium chloride를 기반으로 한 이온성 액체와 urea 부분으로 이루어진 분자 띠를 실리카 나노입자 표면에 결합시커 실리카 나노입자 표면에 팔라듐 나노입자를 고정하였다. 이렇게 고정된 팔라듐-실리카 나노입자 촉매는 Suzuki-Miyaura 커플링 반응에서 촉매 활성의 감소 없이 여러 번 재사용이 가능하였다. 또한 실리카 입자 안에 자성을 띠는 나노입자를 core 구조로 만들고 imidazolium hexafluoroantimonate 로 이루어진 이온성 액체를 실리카 표면에 도입하여 이를 같은 음이온을 지니는 이온성 액체에서 수소화 반응을 진행하였다. 촉매가 자성을 띠는 성질을 이용해 자석을 이용하여 촉매의 재사용을 쉽게 하였고, 반응용매로 사용한 이온성 액체와 촉매 시스템 사이에서 이차적으로 형성된 준 마이셀 구조를 통해 반응물의 크기에 따른 촉매 반응성의 차이를 확인할 수 있었다. 제 3장에서는 페놀로부터 산업적으로 많이 쓰이고 있는 카프로락탐의 합성에 관한 연구로써 팔라듐, 스칸듐 트리플레이트, [bmim][PF6] 로 이루어진 촉매 시스템에서 페놀로부터 카프로락탐까지 3단계의 반응을 한번에 총 67% 의 수율로 진행할 수 있었다. 특히 팔라듐과 스칸듐 트리플레이트가 페놀로부터 사이클로헥사논까지의 수소화 반응에서 높은 수율 (&amp;gt;99.9%) 과 높은 선택성 (&amp;gt;99.9%)을 보이는 촉매로 작용하였으며 스칸듐 트리플레이트와 이온성 액체가 사이클로헥사논에서 cyclohexanone oxime을 거쳐 카프로락탐까지 한번에 반응이 이루어 지는 반응에서의 촉매로 작용하였다. 이 연구의 결과는 다기능성 촉매 시스템을 디자인하는데 있어 유용할 것이며, 반응 단계 사이의 중간과정을 없애고 한번에 진행시킴으로써 카프로락탐의 친환경적인 생산과정을 발전시키는데 기여할 것으로 예상된다.CHAPTER I. Synthesis and Application of Ionic Liquid-Carbon Nanotube Hybrid Catalyst System 4 I-A. Palladium Nanoparticles Supported onto Ionic Carbon Nanotubes as Robust Recyclable Catalysts in Ionic Liquid 5 I-A-1. Introduction 5 I-A-2. Results and Discussion 7 I-A-3. Conclusion 12 I-A-4. Experimental Section 13 I-A-5. References 16 I-A-6. Appendix 18 I-B.The Impact of Anions on the Electrocatalytic Activity in Supported Palladium Nanoparticles onto Ionic Liquid-Carbon Nanotube Hybrids for Oxygen Reduction Reaction 22 I-B-1. Introduction 22 I-B-2. Results and Discussion 25 I-B-3. Conclusion 37 I-B-4. Experimental Section 38 I-B-5. References 45 I-B-6. Appendix 48 I -C. High-Density Assembly of Gold Nanoparticles with Zwitterionic Carbon Nanotubes and Their Electrocatalytic Activity in Oxygen Reduction Reaction 51 I-C-1. Introduction 51 I-C-2. Results and Discussion 53 I-C-3. Conclusion 60 I-C-4. Experimental Section 61 I-C-5. References 68 I-C-6. Appendix 70 I-D. Insight into the Origin of the Positive Effects of Imidazolium Salt on Electrocatalytic Activity: Ionic Carbon Nanotubes as Metal-Free Electrocatalysts for Oxygen Reduction Reaction 73 I-D-1. Introduction 73 I-D-2. Results and Discussion 76 I-D-3. Conclusion 84 I-D-4. Experimental Section 85 I-D-5. References 91 I-D-6. Appendix 94 CHAPTER II. Synthesis and Application of Ionic-Silica Nanoparticle Hybrid Catalyst System 96 II-A. Palladium Nanoparticles Captured onto Spherical Silica Particles using a Urea Cross-linked Imidazolium Molecular band 97 II-A-1. Introduction 97 II-A-2. Results and Discussion 99 II-A-3. Conclusion 104 II-A-4. Experimental section 105 II-A-5. References 109 II-A-6. Appendix 111 II-B. Supported Pd Nanocatalysts onto Ionic Silica-Coated Magnetic Particles for Catalysis in Ionic Liquids 113 II-B-1. Introduction 113 II-B-2. Results and Discussion 115 II-B-3. Conclusion 121 II-B-4. Experimental section 122 II-B-5. References 128 II-B-6. Appendix 130 CHAPTER III. Tandem Catalytic One-Pot Synthesis of ε-Caprolactam from Phenol with Multi-Function Pd/Sc(OTf)3/ Ionic Liquid Catalyst 132 III-A. Introduction 133 III-B. Results and Discussion 136 III-C. Conclusion 142 III-D. Experimental section 143 III-E. References 147 III-F. Appendix 150 Abstract in Korean 17

Arabidopsis dynamin-related protein 3A, DRP3A의 기능 연구

Maste

병원성 미생물 저감화를 위한 DUV-LED 적용 및 최적화 연구

학위논문 (석사)-- 서울대학교 대학원 : 농생명공학부, 2015. 2. 강동현.The UV irradiation for treating food has been approved by the U.S. Food and Drug Administration. So far, most UV treatment is performed by low-pressure (LP) UV lamp of 253.7 nm. But these lamps have some potential risks such as possibility of mercury leakage, short life time and requirement of significant amount of energy. As an alternative to UV mercury lamps, deep UV-LEDs (DUV-LEDs) are of great interest for disinfection. The objectives of this study were to examine the basic spectral properties of DUV-LEDs and the effects of UV-C irradiation for inactivating food-borne pathogens on solid medium as well as in water. A cocktail of Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes strains was spread-plated onto each selective medium or inoculated to the sample of water. As temperature increased, intensity of LED was slightly decreased while LP lamp showed intensity increasing until it reaches to the peak temperature around 30 °C. As the dose of UV radiation increased from 0 to 1.67 mJ/cm2, all kinds of food-borne pathogens showed great reduction by >5 log. When treatment temperature increases, reduction level of E. coli O157:H7 and S. Typhimurium were gradually increased, but L. monocytogenes showed no significant different (P > 0.05). Only for E. coli O157:H7, the significant reduction (P < 0.05) was observed at 90% relative humidity condition compared with other conditions such as 30 and 60 %. In case of 10 ml of water treatment, levels of surviving cells of all pathogens were reduced to below the detection limit (1.0 log CFU/g). At the scaled-up test, surviving populations of general bacteria were reduced by 5.38 and 4.37 log CFU/ml for 2 L and 3 L of water, respectively, and lowered to below detection limit for 1 L of water at the dose of 3 mJ/cm2. Linear correlation between inactivation and dosage of UV irradiation was indicated at continuous water decontamination system. The result of this study suggests that a novel type of DUV-LEDs applicability was confirmed as an alternative to the lamp type in inactivating food-borne pathogens.ABSTRACT.................................................................................................. III CONTENTS....................................................................................................V LIST OF TABLES......................................................................................VIII LIST OF FIGURES........................................................................................X I. INTRODUCTION........................................................................................1 II. MATERIALS AND METHODS................................................................4 2.1. Spectral characteristics of DUV-LED 2.1.1. Collimated UV radiation design.................................................4 2.1.2. Experimental setup......................................................................6 2.1.3. Irradiance measurements.............................................................8 2.2. Effect of various conditions on inactivation of food-borne pathogens by using DUV-LED 2.2.1. Bacterial strains and inoculum conditions..................................8 2.2.2. Culture preparation...................................................................9 2.2.3. Culture inoculation....................................................................9 2.2.4. UV treatment.............................................................................10 2.2.5. Bacterial enumeration...............................................................11 2.2.6. Statistical analysis.....................................................................11 2.3. UV treatment for water decontamination 2.3.1. Bacterial strains and inoculum conditions................................12 2.3.2. Culture preparation...................................................................13 2.3.3. Culture inoculation....................................................................13 2.3.4. UV treatment.............................................................................14 2.3.5. Bacterial enumeration...............................................................16 2.3.6. Statistical analysis.....................................................................16 III. RESULTS................................................................................................17 3.1. Spectral characteristics of DUV-LED 3.1.1. Emission spectrum of DUV-LED.............................................17 3.1.2. Comparison of properties between DUV-LEDs and LP lamps .............................................................................................................19 3.1.3. Assessment of the effective area by LED arrangements...........21 3.2. Effect of various conditions on inactivation of food-borne pathogens by using DUV-LED 3.2.1. Bactericidal effect by UV treatment on media..........................25 3.2.2. Effect of UV irradiation temperature........................................27 3.2.3. Effect of UV irradiation humidity.............................................29 3.3. UV treatment for water decontamination 3.3.1. Bactericidal effect by UV treatment at batch water system......31 3.3.2. Bactericidal effect by UV treatment at scale-up system...........33 3.3.3. Bactericidal effect by UV treatment at continuous water system .............................................................................................................37 IV. DISCUSSIONS.......................................................................................45 V. REFERENCES….....................................................................................51 VI. 국문초록................................................................................................58Maste