살기좋은 우리동네 만들기(Improvement of residential community)

노트 : 제 4차 국토종합계획수립연구(주거부문) 이 책은 국토연구원의 자체 연구물로서 정부의 정책이나 견해와는 상관없음을 밝혀둡니다

교통안전 추진체계 정비방안 연구(A study on the transportation safety system improvement plan of Korea)

노트 : 이 연구보고서의 내용은 국토연구원의 자체 연구물로서 정부의 정책이나 견해와는 상관없습니다

중장기 SOC 투자전략에 관한 연구(The middle and long term investment strategies of transporation social overhead capitals)

노트 : 이 연구보고서의 내용은 국토연구원의 자체 연구물로서 정부의 정책이나 견해와는 상관없습니다

(A) Study on the Fabrication of Planar Buried Heterostructure Laser Diode Using Meltback Method

A PBH-LD, a kind of strongly index guided laser, has been made by a meltback method by using a vertical LPE system which was made in our laboratory for ourselves. Formation of a mesa shape by a meltback method has an advantage in the reduction of damages on a substrate due to chemical etching and heating during regrowth. After the investigation of several characteristics of meltback solutions and meltback temperature, we confirmed that both of chemical etching and meltback method should be used to make a high performance PBH-LD. Therefore, we have formed mesa shapes successively with chemical etching and the meltback method. It is considered that the characteristics of the interface between the substrate and current blocking layers grown after the meltback may be excellent because of high meltback temperature of 610℃. The width of an active layer has been controlled to be 0.8 to 1.2㎛ so that the fabricated LD could operate with single mode in the lateral direction. To reduce the leakage current of current blocking layers, the widths of p-InP and n-InP layer have been grown to be 1.2㎛ and 1.6㎛, respectively. From the measurement of electric and optical characteristics of the fabricated MQW-PBH-LD, it was confirmed to be operated with low current and high performance. When the length of resonator was 300㎛, its characteristics were as follows: the threshold current of 10mA, the internal quantum efficiency of 82%, the internal loss of 9.2cm-1, and characteristic temperature of 65K. From the measurement of far-field pattern, we confirmed that it was operated with single mode in both directions parallel and normal to the junction interface. And we observed the variation of threshold current varying the leakage width at a certain cavity length and then applying the same widths to different cavity lengths and as a consequence, we clarified that the threshold current became low in the decrease of the leakage width and in the increase of the ratio of specific resistivity of leakage region to active region. We also made a comparison between the calculated threshold current in the absence of leakage region and the measured threshold current in the opposite case. As a result, the ratio of specific resistivity was about 0.5 in the measured LD, which has the width of a active layer of 1.4㎛ and leakage width of 0.6㎛

산화그래핀을 이용한 항바이러스 약물 스크리닝 플랫폼 및 생리활성 임플란트 소재 개발

학위논문(박사) -- 서울대학교대학원 : 자연과학대학 화학부, 2022.2. 민달희.Novel technologies to treat diseases, such as tissue engineering and drug discovery methodologies, have developed in conjunction with advances in civilization and science. However, certain problems in the field of life sciences have not received sufficient attention and remain unresolved. A classic example is the discovery of therapeutic agents for viral infections. In the globalized modern society, it is imperative to protect and treat humanity from viral infections. However, due to the diversity of viruses and the rapid emergence of mutations, it is impossible to respond immediately using the current drug development processes. Therefore, the development of a new drug discovery method is necessary to overcome this problem and allow the quick discovery of antiviral drugs. Another example is the unmet need to increase the bioactivity of implant materials. Although biocompatibility is essential to prevent adverse effects following the implantation of external materials into the body, bioactivity, which described interactions between the prosthetic material and biological components, is more critical in securing the long-term stability of prosthetic materials. Thus, many studies are being conducted to increase bioactivity by controlling the surface properties of the implant material in various ways. Nevertheless, compared to minutely controlling the thickness and roughness of its oxide film, there is a continuing need for a modification method that is somewhat simpler. Nanobiotechnology refers to the combination of nanotechnology, which involves the development of new materials by identifying their physical properties at the atomic or molecular level, and biotechnology, which refers to the study of life phenomena. Nanobiotechnology can be applied to solve biological and biotechnological problems unsolvable by classical approaches. Therefore, the core goal of nanobiotechnology is to develop new nanomaterials with excellent properties that can be applied to various fields such as biosensors, biochips, drug delivery, therapeutics, and tissue regeneration. Graphene oxide (GO) is an attractive nanomaterial due to its excellent physicochemical properties, originating from its oxygen functional groups and sp2 carbon domains. As a representative feature, GO can quench fluorescent molecules located within 20 nm by adsorption. Therefore, GO is being used in research on various fluorescence-based biosensors. In addition, because GO has excellent biocompatibility and bioactivity to induce bone regeneration and cell differentiation, it is being used in regenerative medicine and prosthetic research. Herein, we suggest a solution to the problems mentioned above using GO. First, we will address the development of a drug screening platform for rapid antiviral drug discovery: We developed a graphene oxide-based RNA viral helicase assay named RheGO. This assay could be used to analyze helicase activity in real-time with excellent reproducibility and reliability, and was applicable to antiviral drug screening. The antiviral activity of the hit compound identified with RheGO was also confirmed in vitro and in vivo. Second, we will address the need to improve the bioactivity of implant materials: We coated GO on the surface of the implant material with simple processing. As a result, we confirmed that the adhesion and proliferation of gingival fibroblasts increased when GO was coated. Moreover, we confirmed that the expression of focal adhesion genes was increased when gingival fibroblasts came into contact with GO. Thus, we showed that problems that were difficult to solve with classical methods could be solved with new approaches using nanobiotechnology. Moreover, we believe that many medical and biotechnology problems can potentially be solved using GO to develop new methods for antiviral drug discovery and new materials with excellent bioactivity.문명과 과학기술이 발전하면서 질병을 치료하기 위한 약물의 발굴 방법과 조직공학 기술 또한 함께 발전하였다. 그러나 생명과학 분야에서 상대적으로 주목받지 못하여 아직도 해결되지 않은 문제들이 존재하고 있다. 대표적인 예로서 바이러스 감염 질환 치료제 발굴을 들 수 있다. 세계화된 현대 사회에서 바이러스 감염으로부터 인류를 보호하고 치료하는 것이 얼마나 중요한지는 이루 말할 수 없다. 그러나 바이러스의 다양성과 빠른 변이의 출현으로 인해 기존의 약물 개발과정으로는 신속한 대응이 불가능하다는 한계가 있다. 따라서 이를 극복하기 위한 새로운 약물 발굴방법 개발과 이를 이용한 신속한 항바이러스 약물 발굴을 해야 한다. 또 다른 예로서, 임플란트 물질의 생리활성을 높이는 것이다. 외부 물질을 생체 내로 삽입할 때 생체내 부정적인 영향이 나타나지 않도록 하는 생체 적합도는 필수적이지만, 인공삽입술에서 인공삽입물질과 생체분자및 세포들 간의 강력한 상호작용을 할 수 있도록 생리활성을 높이는 것은 인공삽입물질의 장기간 안정성을 확보할 수 있다는 점에서 더욱 중요한 의미를 갖는다. 비록 인공삽입물로 활용될 수 있는 물질 종류가 다양하지 않지만, 그럼에도 불구하고 물질의 표면 특성을 여러가지 방법으로 조절하여 생리활성을 높이는 연구들이 수행되고 있다. 그러나 물질 표면의 산화막 두께 및 거칠기를 조절하는 섬세한 방법에 비해 다소 간편한 개질 방법에 대한 요구가 지속되고 있다. 나노바이오기술은 원자나 분자 단위에서의 물성을 규명하여 새로운 물질을 개발하는 나노기술과 이를 이용하여 인간의 질병 및 생명현상을 연구하는 바이오기술이 결합된 것으로서, 고전적인 접근 방법으로 해결하지 못한 생물학 및 생명공학적 문제를 해결할 수 있는 기술이다. 그렇기 때문에 새로운 나노물질을 개발하고 뛰어난 물성을 갖는 나노물질을 바이오센서, 바이오칩, 약물전달, 치료제, 조직재생과 같은 다양한 분야에 적용시키는 것이 나노바이오기술의 핵심이라 할 수 있다. 특히, 다양한 나노물질 중에서 산화그래핀은 산소 작용기와 그래핀 도메인을 가지고 있으며 이로 인해 뛰어난 물리화학적 특징을 보이는 매력적인 나노물질이다. 대표적인 특징으로서, 산화그래핀은 표면에 흡착되거나 20 nm 내에 위치한 형광물질을 소광 시킬 수 있다. 이를 기반으로 다양한 형광 기반 바이오센서연구에 산화그래핀이 활용되고 있다. 또한 산화그래핀은 뛰어난 생체적합성과 뼈 재생 및 세포 분화를 유도할 수 있는 생리활성 특징을 가지고 있다. 이와 같은 특징으로 인해, 재생의학 및 인공삽입물 연구에 산화그래핀이 쓰이고 있다. 본 논문에서 우리는 산화그래핀을 이용하여 앞서 언급한 두 가지 문제에 대한 해결방법을 제시하고자 한다. 첫째, 신속한 항바이러스 약물 발굴을 위한 약물 스크리닝 플랫폼 기술 개발: 우리는 산화그래핀 기반의 RNA 바이러스성 헬리케이즈 활성 분석 기술인 RheGO를 개발하였다. 형광이 개질된 핵산 기질을 사용하여 실시간으로 핼리케이즈의 활성을 확인할 수 있는 본 분석 기술은 뛰어난 재현성과 신뢰성을 보여주었고, 항바이러스 약물 스크리닝에 적용이 가능함을 보였다. 그리고 발굴된 약물 후보군의 세포 수준 및 동물모델 수준에서 유의미한 항바이러스 효과를 확인하였다. 둘째, 임플란트 물질의 생리활성도 향상: 우리는 산화그래핀을 임플란트 물질 표면에 부착하여 그 영향을 확인하였다. 연구 결과 우리는 임플란트 물질에 산화그래핀을 코팅하면 치은섬유아세포의 부착 및 증식이 증가함을 확인하였다. 그리고 이는 치은섬유아세포가 산화그래핀과 접촉할 때 초점접착 유전자의 발현이 증가되어 나타난 결과임을 확인하였다. 본 연구 결과에서 우리는 고전적인 방법으로 해결하기 어려운 문제를 나노바이오기술을 이용한 새로운 접근법으로 해결할 수 있음을 보여주었다. 따라서 우리는 나노 물질인 산화그래핀을 활용하여 항바이러스 약물 발굴을 위한 새로운 방법 개발 및 조직공학을 위한 생리활성이 뛰어난 새로운 물질을 개발함으로써, 향후 많은 의료 및 생명공학 문제들을 해결할 수 있을 것으로 기대한다.Abstract Table of Contents List of Figures Chapter 1. Introduction 1 1.1 Graphene Oxide: its Applications as Biosensor and Bioactive material 1 1.2 Description of Research 4 1.2.1 Identification of a Direct-acting Antiviral Agent Targeting RNA Helicase via a Graphene Oxide Nanobiosensor 4 1.2.2 Graphene Oxide-treated Surface on Pure Titanium Implant Materials Promotes Adhesion and Proliferation of Human Gingival Fibroblast 6 1.3 References 7 Chapter 2. Identification of a Direct-acting Antiviral Agent Targeting RNA Helicase via a Graphene Oxide Nanobiosensor 11 2.1 Introduction 11 2.2 Results 15 2.3 Conclusion 37 2.4 Materials and Methods 38 2.5 References 50 Chapter 3. Graphene Oxide-treated Surface of Pure Titanium Promotes Adhesion and Proliferation of Human Gingival Fibroblast 57 3.1 Introduction 57 3.2 Results 59 3.3 Conclusion 71 3.4 Materials and Methods 72 3.5 References 78 Chapter 4. Conclusion 80 Summary in Korean (국문 요약) 82 Acknowledgement 85 Curriculum Vitae 87박

The Influence of Food Ingestion and Sample Storage on Direct LDL-Cholesterol Measurement by Immunoseparation Method

Background : Elevated level of low density lipoprotein-cholesterol (LDL-C) is one of the major risk factors for the development of coronary heart disease. Direct LDL-C determination method by immunoseparation (DLDL-C) recently developed is claimed not to be influenced by food ingestion. We re-evaluated the effects of diet and storage conditions for this method. Methods : Samples were collected from thirty-two medical college students before and after meal to study the effects of diet on this method. We compared the difference of LDL-C of filtered samples between refrigerated and frozen state. We also compared direct and indirect calculated measurements of LDL-C with ultracentrifugal beta-quantification (BQLDL-C) method. Results : Morning 2-hour-postprandial specimen can be acceptable with no minimal significant bias, but afternoon 2-hour or 4-hour-postprandial specimen cannot be recommended due to significant negative bias (8.6-9.6%). Storage of filtered samples showed no significant difference between frozen and refrigerated state. Calculated LDL-C when triglyceride level is more than 400 mg/dL was not reliable due to large proportional and constant bias. In contrast, DLDL-C showed good accuracy comparing with BQLDL-C (y=0.909x＋3.3, r=0.869, n=9, x=BQLDL-C, y=DLDL-C). Conclusions : In conclusion, morning two-hour postprandial specimens can be acceptable for DLDL-C, but afternoon postprandial specimens may not be recommended due to significant negative bias. DLDL-C seems to be reliable and useful especially for hypertriglyceridemic patients or follow-up cases of hypercholesterolemia with normal triglyceride or HDL-C levels.ope

Prevalence and Risks of Depression and Substance Use Among Adults Living with HIV in the Asia-Pacific Region

ope

The Effect of Red Pepper and Capsaicin on Gastric Emptying

Background/Aims: Capsaicin stimulates the release of several neuropeptides and has diverse effects on gastrointestinal function. We investigated the effect of intragastric red pepper or capsaicin on the gastric emptying in human. Methods: Fourteen healthy male volunteers were recruited. Gastric emptying was assessed by radio-opaque markers (ROMs) method and plasma acetaminophen (AAP) levels. Results: The clearance of ROMs at 2 hours and 3 hours was 10.6 ±15.9 and 73.1 ±34.6% after administration of placebo, 17.6 ±26.0 and 78.7 ±40.2% after administration of red pepper 3 g 27.8 ±34.0 and 73.2 ±31.9% after administration of red pepper 6 g, 2.1 ±5.1 and 15.5 ±20.7% afte administration of capsaicin 17.3 mg. Capsaicin significantly delayed the gastric emptying of ROMs The serum AAP concentrations were measured at 30, 45, 60, 75 and 90 min after administration o placebo (4.09 ±3.45, 8.09 ±4.13, 13.55 ±4.90, 15.50 ±3.44 and 13.0 ±7.53 μg/ml), red pepper 3 g (5.63 ±4.84, 8.88 ±4.76, 14.25 ±5.01, 15.11 ±5.16 and 16.80 ±6.57 μg/ml), red pepper 6 g (7.0 ± 7.19, 8.09 ±5.63, 12.09 ±6.04, 13.73 ±4.65 and 14.28 ±3.77 μg/ml), capsaicin 17.3 mg (4.50 ±2.88 , 7.17 ±3.19, 11.50 ±4.76, 11.17 ±3.71 and 13.33 ±3.72 μg/ml). Intragastric red pepper or capsaicin made no significant difference of serum acetaminophen level from placebo. Conclusions: Intragastric administration of capsaicin delayed gastric emptying of indigestible solid meal, whereas red pepper did not. The gastric emptying of liquid meal was affected by neither capsaicin nor red pepper.ope

Direct Measurement of High-Density Lipoprotein Cholesterol Evaluated

Background :Serum high density llpoproteln (HDL)-cholesterol level IS used as an assessment of the risk of coronary heart disease. In this study, we evaluated direct measurement of HDL-cholesterol in serum with polyethylene-modlfled enzymes and sulfated a-cyclodextrin Method :We evaluated the precision, the lower limit of detection, the recovery rate, the linearity, the Interference for hemoglobin and the comparlslon with the result of HDL-cholesterol measured by selective preclpltatlon method We also studied the specificity of this direct method for very low density llpoproteln (VLDL) and low density lipoprotein (LDL) Result :The total ImprecIsIon was 3 8% (low), 3 5% (mlddle), 3 2% (high) The lower limit of detectjon was 0 mg/L The recovery rate was satisfactory The linearlty was also (r`=O 99) This method showed a good correlation (r`=O 97) with the selective preclpltatlon method in HDL-cholesterol measurement VLDL-cholesterol (up to 300 mg/L) Increased HDL-cholesterol only less than 3% but Increased VLDL-cholesterol to 400 mg/L, more than 750 mg/L caused 5% and 15% of overestlmatlon of HDL-cholesterol, respectively LDL-cholesterol (142-l ,073 mg/L) Increased or decreased HDL-cholesterol by some degree (about 15%). Hemoglobin (up to 3,000mg/L) did not influence this assay Conclusion :The drrect measurement of HDL-cholesterol IS satisfactory method in HDL-cholesterol measurement In good analytlcal performance and may be anticipated to reduce workload of laboratory because the sample pretreatment IS not necessaryope

Design and Fabrication of 1.3㎛ Uncooled Planar Buried Heterostructure Laser Diode

Uncooled operation of the laser diodes up to 85 ℃ is an important requirement, because thermo-electric cooler(TEC) of the laser modules is too expensive. In this thesis, we have theoretically investigated a 1.3 ㎛ InGaAsP/InP Planar Buried Heterostructure-Laser Diode(PBH-LD) for high temperature operation with low threshold current without temperature control. We adopted the strained MQW structure as an active region and PBH among strongly index-guided structures in order to have low current operation. Based on the rate equations, which describe rate change between the carrier density and the photon density, we proposed the electrical equivalent circuit of PBH-LD. In the PBH LD, the confinement of the injected current to the active region is achieved through reverse-biased homojunctions. The leakage current paths are identified by a major circuit element in each branch, e.g., the diode(p-n forward biased InP homojunction), the thyristor(p-n-p-n InP) in the electric equivalent circuit model. For the diode leakage path in the electric circuit model, p-InP blocking layer is equal to a resistor according to the concentration and thickness. For the thyristor leakage path in the model, p-n-p-n current blocking layer is equal to two transistors such as p-n-p and n-p-n type. We calculated the resistor according to the concentration and thickness of p-InP blocking layer and the connection width, which is the minimum distance between active layer and n-InP blocking layer. The transistor gains are calculated according to the concentration of each layer. In order to optimize the concentration and thickness of each layer, the electrical equivalent circuit model was simulated with PSPICE circuit simulator. Based on the theoretical analysis of electric equivalent circuit model, the PBH-LD is fabricated by using the vertical type Liquid Phase Epitaxy(LPE) system, which has been made by hands. In order to form mesa shape, wet etching and meltback method are executed in turn. And meltback method has the advantage of reduction of damage on a substrate due to wet etching and thermal damage during growth. After forming mesa shape on the substrate, p-n-p current blocking layers were grown at 611 ℃ with the cooling rate of 1 ℃/min by two phase solution technique. And then, SiNx is removed, p-InP and ohmic contact layers are regrown by 600 ℃ with the same cooling rate. The light output power versus injection current and the spectrum characteristics of the fabricated PBH-LDs were measured with various temperature. From the measurement, the threshold current was 6 ㎃ and the light output power at 25 ℃ was about 22 ㎽ with 300 ㎛ cavity length at 100 ㎃. The characteristic temperature from 25 ℃ to 45 ℃ is 50 K, and from 45 ℃ to 65 ℃ is 44 K. Also, From the spectrum characteristic measurement, we confirmed the central wavelength was 1310 ㎚ and the temperature dependence of lasing wavelength was 5 Å/℃. We also measured the far field pattern of fabricated PBH-LD and the full width at half maximum(FWHM) was 35o(∥)×40o(⊥).제 1 장 서론 1 제 2 장 Uncooled PBH-LD의 이론적 해석 6 2.1 PBH-LD의 모드 해석 7 2.1.1 횡모드 해석 9 2.1.2 측모드 해석 14 2.2 활성층의 온도 의존성 해석 18 2.2.1 전류밀도와 재료 이득의 온도 의존성 18 2.2.2 미분양자효율과 특성온도의 온도 의존성 21 2.2.3 발진임계전류의 온도 의존성 27 2.3 PBH-LD의 누설 전류 32 2.3.1 활성 영역의 누설 전류 32 2.3.2 전류차단층을 통한 누설전류 38 제 3 장 Uncooled PBH-LD의 설계 44 3.1 비율 방정식을 통한 등가회로 모델 44 3.2 MQW 구조의 전기적 등가회로 설계 49 3.3 누설 영역의 전기적 등가 회로 설계 54 3.4 PBH-LD의 전기적 등가 회로 해석 60 제 4 장 Uncooled PBH-LD의 제작 및 특성 평가 68 4.1 InGaAsP/InP PBH-LD의 제작 68 4.2 PBH-LD의 전기&#8228광학적 특성 실험 및 평가 78 제 5 장 결론 90 참고문헌 92 부록 10