198 research outputs found
A Case of Nasopharyngeal Schwannoma Treated with Endoscopic Tumor Resection
Schwannoma is generally known as benign tumor originated from Schwann cells of peripheral nerve sheaths. This tumor is characterized by well-circumscribed, encapsulated, and slow growing. It is reported that it mainly appears in the head and neck area, but it is known that paranasal sinus and sinus are rarely seen within 4%. We describe an incidental schwannoma case arising from the nasopharyngeal level of a 41-year-old woman. The patient visited the out-patient clinic with a nasopharyngeal mass found incidentally on a health check. The tumor was then totally removed by endoscopic surgery without complications and diagnosed as a schwannoma. She had no sequelae or recurrence for 1year after surgery.ope
An Alternative Dendritic Cell-Induced Murine Model of Asthma Exhibiting a Robust Th2/Th17-Skewed Response
Purpose: Simple and reliable animal models of human diseases contribute to the understanding of disease pathogenesis as well as the development of therapeutic interventions. Although several murine models to mimic human asthma have been established, most of them require anesthesia, resulting in variability among test individuals, and do not mimic asthmatic responses accompanied by T-helper (Th) 17 and neutrophils. As dendritic cells (DCs) are known to play an important role in initiating and maintaining asthmatic inflammation, we developed an asthma model via adoptive transfer of allergen-loaded DCs.
Methods: Ovalbumin (OVA)-loaded bone marrow-derived DCs (BMDCs) (OVA-BMDCs) were injected intravenously 3 times into non-anesthetized C57BL/6 mice after intraperitoneal OVA-sensitization.
Results: OVA-BMDC-transferred mice developed severe asthmatic immune responses when compared with mice receiving conventional OVA challenge intranasally. Notably, remarkable increases in systemic immunoglobulin (Ig) E and IgG1 responses, Th2/Th17-associated cytokines (interleukin [IL]-5, IL-13 and IL-17), Th2/Th17-skewed T-cell responses, and cellular components, including eosinophils, neutrophils, and goblet cells, were observed in the lungs of OVA-BMDC-transferred mice. Moreover, the asthmatic immune responses and severity of inflammation were correlated with the number of OVA-BMDCs transferred, indicating that the disease severity and asthma type may be adjusted according to the experimental purpose by this method. Furthermore, this model exhibited less variation among the test individuals than the conventional model. In addition, this DCs-based asthma model was partially resistant to steroid treatment.
Conclusions: A reliable murine model of asthma by intravenous (i.v.) transfer of OVA-BMDCs was successfully established without anesthesia. This model more accurately reflects heterogeneous human asthma, exhibiting a robust Th2/Th17-skewed response and eosinophilic/neutrophilic infiltration with good reproducibility and low variation among individuals. This model will be useful for understanding the pathogenesis of asthma and would serve as an alternative tool for immunological studies on the function of DCs, T-cell responses and new drugs.ope
Development of a Direct Numerical Simulation Method on the Nonlinear Dynamic Responses among Wave, Structure and Seabed
์ฐ์๊ตฌ์กฐ๋ฌผ์ ์ค์นํ ๋ ์ง๋ฐ์ ์์ ์ฑ ํด์์ ์์ด์ ๊ฐ์ฅ ์ค์ํ ๋ฌธ์ ์ ์ผ๋ก ํ๋์ ์กด์ฌ๋ฅผ ๋ค ์ ์๋ค. ํด์ ์ง๋ฐ์ ํ๋์ ์ํ ๋ฐ๋ณตํ์ค์ ๋ฐ๋ ํน์ฑ์ ๊ฐ์ง๋ฏ๋ก ์ง์ง๊ณผ ๊ฐ์ ์ก์์์์ ์ง๋ฐ ๊ฑฐ๋๊ณผ๋ ์๋นํ ๋ค๋ฅธ ํน์ง์ ๊ฐ๋๋ค. ์ง๋ 10์ฌ๋
๋์ ํใ๊ตฌ์กฐ๋ฌผใํด์ ์ง๋ฐ์ ์ํธ๊ฐ์ญ์ ๋ํ ์ฐ๊ตฌ์ ๋ฐ์ ์ ๋ณด์ฌ ์๋ค. ๊ทธ๋ฌ๋ ํใ๊ตฌ์กฐ๋ฌผใํด์ ์ง๋ฐ์ ์ํธ๊ฐ์ญ์ ๋ํด ์ด์ ์ ์ฐ๊ตฌ์๋ค์ ํด์ ๋ถํฌ๊ณผ์ ๊ฐ์ ์ ์ด์ ์ ๋๊ณ ์๋ค. ํ๋ํ์ค์ ์ํ ์ง๋ฐ๋ด ๊ฐ๊ทน์์์ ์ฐ์๊ตฌ์กฐ๋ฌผ ๋ถ๊ทผ์์์ ์ธ๊ตด๊ณผ ๊ฐ์ ์ง๋ฐ์ ์์ ์ฑ์ ์ฐ๊ตฌํ๋๋ฐ ์ค์ํ ์์์ด๋ค. ํใํด์ ์ง๋ฐ์ ์ํธ๊ฐ์ญ์ ๋ํ ํด์๋ชจํ์ด ์์ ํ ํํ์ ํด๋ฅผ ์ฃผ๊ธฐ ๋๋ฌธ์ ์ํธ๊ฐ์ญ๋ฌธ์ ์ ๊ธฐ๋ณธ์ ์ธ ํน์ฑ๋ค์ ์์น๋ชจํ์ ๋นํ์ฌ ์ฝ๊ฒ ๋๋ ํจ์จ์ ์ผ๋ก ๋ถ์๋ ์ ์์ผ๋ ์ด๋ฌํ ํด์์ ์ ๊ทผ์ ๋จ์ํ ํด์ ์ง๋ฐ์ธ ๊ฒฝ์ฐ๋ก ์ ์ฝ๋๊ณ ์์ฌ์ด ๋ณํ๋ ๊ฒฝ์ฐ๋ ํด์ ์ง๋ฐ์ ๊ตฌ์กฐ๋ฌผ์ด ๋์ฌ์์ ๊ฒฝ์ฐ ์ ์ฉํ๊ธฐ๊ฐ ์ด๋ ต๋ค. ๋๋ถ๋ถ์ ์ฐ์๊ตฌ์กฐ๋ฌผ, ํนํ, ์ผ์ด์จ ํํ์ ๋ฐฉํ์ ๋ ์ ์ ๋ ๊ธฐ์ด์ง๋ฐ๊ณผ ๊ฐ์ด ๋์ ์ผ๋ก ๊ฑฐ๋ํ๋ค. ์ต๊ทผ ํใ๊ตฌ์กฐ๋ฌผใํด์ ์ง๋ฐ์ ๋น์ ํ ์ํธ๊ฐ์ญ์ ํด์ํ๊ธฐ ์ํ์ฌ ๊ฒฝ๊ณ์์๋ฒ(BEM)๊ณผ ์ ํ์์๋ฒ(FEM), VOF๋ฒ๊ณผ ์ ํ์์๋ฒ(FEM)์ ๋ณ์ฉํ ์์นํด์๊ธฐ๋ฒ์ด ์ ์๋์๋ค. ํ์ง๋ง, ์ด๋ฌํ ์์นํด์๊ธฐ๋ฒ์ ํ๋์ฅ๊ณผ ์ง๋ฐ๋ถ์ ๋ถ๋ฆฌ์ ๋ฐ๋ฅธ ๊ฐ์ ๋๋ฌธ์ Hybrid๊ธฐ๋ฒ์ ์ ์ฉํ๊ณ ์๋ค. ๋ฐ๋ผ์ ํ๋ํ์คํ์์ ํใ๊ตฌ์กฐ๋ฌผใํด์ ์ง๋ฐ์ ๋์ ์๋ต์ ์ ์ ํ ๋ชจ์ํ๊ธฐ ์ํ ์์น๋ชจ๋ธ์ ๊ฐ๋ฐ์ด ํ์ํ๋ค. ๋ณธ ์ฐ๊ตฌ์์๋ ํใ๊ตฌ์กฐ๋ฌผใํด์ ์ง๋ฐ์ ๋น์ ํ๋์ ์๋ต์ ํด์ํ๊ธฐ ์ํ์ฌ ์ง์ ์์นํด์๊ธฐ๋ฒ(DNS)์ด ์๋กญ๊ฒ ์ ์๋์๋ค. ๋ณธ ์์นํด์๊ธฐ๋ฒ์ Darcy ์ Forchheimer ์ ํญ๋ ฅ์ด ์ถ๊ฐ๋ Porous Body Model์ ๊ธฐ์ดํ๊ณ ์๋ค. ํด์ ์ ํฉ๋ฉด์์๋ ์๋ ฅ๊ณผ ์ ๋์ ์ฐ์์ ๊ณ ๋ คํจ์ผ๋ก์จ ์ ์ฒด๋ถ์์ ๋ค๊ณต์ง๋งค์ง๋ก์ ๋ณํ๊ฐ ๊ฐ๋ฅํ๋ค. ์ด๋ฌํ ๋ฐฉ์ ์์ ์ ์ ํ ์ ํญ๊ณ์๋ฅผ ์กฐ์ ํจ์ผ๋ก์จ ๋น์ ํ ์ธต๋ฅํ๋ฆ์์ญ์์๋ถํฐ ์์ ๋๋ฅํ๋ฆ์์ญ์๊น์ง ์์น๋ชจ์๊ฐ ๊ฐ๋ฅํ๊ฒ ๋๋ค. ์๋กญ๊ฒ ์ ์๋ ๋ณธ ์์นํด์๊ธฐ๋ฒ์ ํใํฌ๊ณผ์ฑ์ ์ ์ ๋ํด์ Kioka et al.(1994), ํใ๋ชจ๋์ง๋ฐ์ ๋ํด์๋ Yamamoto et al.(1978), ํใํฌ๊ณผ์ฑ์ ์ ใ๋ชจ๋์ง๋ฐ์ ๋ํด์๋ Mizutani et al.(1997), ํใํผ์ฑ๋ฐฉํ์ ใ๋ชจ๋์ง๋ฐ์ ๋ํด์๋ Mostafa et al.(1999)์ ์คํ์น์ ๊ฐ๊ฐ ๋น๊ตํ์ฌ ์ข์ ์ผ์น์ฑ์ ๋ณด์๋ค. ๋ํ, ์๋กญ๊ฒ ์ ์๋ ์์นํด์๊ธฐ๋ฒ์ ์ ์ฉ์ฑ์ ๊ฒํ ํ๊ธฐ ์ํ์ฌ ํใ๊ตฌ์กฐ๋ฌผ(์ ์ , ํผ์ฑ๋ฐฉํ์ )ใํด์ ์ง๋ฐ์ ๊ฒฐํฉ์ ์ํ ํ๋์ฅ ๋ฐ ๊ฐ๊ทน์์์ ๋ณํ ๋ฑ์ด ์์ธํ ๋
ผ์ ๋์๋ค.For the geotechnical analysis in the construction and design of the coastal structures, one of the most important factors is an existence of wave. It is expected that the soil behaviours in the seabed subjected to cyclic wave loads are much different from that on the ground subjected to dynamic forces such as earthquake. In the past few decades, considerable effects have been devoted to analysis the phenomenon of waveใstructureใseabed interaction. However, most of the researches for waveใstructureใseabed interaction have been focused on the assumption of rigid seabed. The wave-induced pore pressure in the seabed are key factor in studying the stability of the seabed in the vicinity of coastal structure, like a toe scouring. Since analytical model for waveใseabed interaction gives a closed from solution, the fundamental characteristics can be analyzed easily and efficiently compared with numerical methods. But, analytical model is difficult to be applied to the cases with varying water depth or structure located on the seafloor, because this approach is limited to the simple geometrical case of the seabed. The most of the coastal structure behave dynamically with foundation soil and pore fluid in soil under wave loadings, particularly caisson type and submerged breakwater. Recently, Boundary Element Method(BEM)-Finite Element Method(FEM), Volume Of Fluid(VOF)-Finite Element Method(FEM) models for the nonlinear dynamic interaction among wave, structure and seabed is presented. But, BEM-FEM and VOF-FEM models are linked through applying hybrid numerical technique because of the assumptions that wave fields and seabed regime are uncouplied. Therefore, it is necessary to develope numerical model for simulating properly the dynamic responses among waveใstructureใseabed under wave loadings. In this paper, Direct Numerical Simulation(DNS) is newly proposed to study the nonlinear dynamic interaction among waveใstructureใseabed. This numerical model is based on the Porous Body Model in which the Darcy and Forchheimer friction are included. The transition from the fluid to the porous medium is achieved through a continuous of dynamic pressure and flow flux at the interfacial seabed surface. These equation can simulate the nonlinear laminar and transitional to full turbulent flow regimes through adjusting the resistance coefficient values. A newly proposed numerical model favorably well matchs with experimental results presented by Kioka et al.(1994) for waveใpermeable submerged breakwater, Yamamoto et al.(1978) for waveใcoarse sand, Mizutani et al.(1998) for waveใpermeable submerged breakwaterใcaorse sand and Mostafa et al.(1999) for waveใcomposite breakwaterใcaorse sand, respectively. Moreover, For the sake of discussing applicability of newly proposed numerical model, variations of the wave fields and pore pressure caused by coupling of waveใstructureใseabed, particularly submerged and composite breakwater, are discussed in detail.์ 1์ฅ ์ ๋ก 1
1.1 ์ฐ๊ตฌ์ ๋ฐฐ๊ฒฝ 1
1.2 ๊ธฐ์กด์ ์ฐ๊ตฌ 3
1.2.1 ํใ๊ตฌ์กฐ๋ฌผ์ ์ํธ๊ฐ์ญ 3
1.2.2 ํใํด์ ์ง๋ฐ์ ์ํธ๊ฐ์ญ 5
1.2.3 ํใ๊ตฌ์กฐ๋ฌผใํด์ ์ง๋ฐ ์ํธ๊ฐ์ญ 6
1.3 ์ฐ๊ตฌ์ ๋ชฉ์ 7
1.4 ์ฐ๊ตฌ์ ๊ตฌ์ฑ 7
์ 2์ฅ VOF-FDM ๋ชจ๋ธ 9
2.1 ์์นํด์ ์ด๋ก 9
2.1.1 ๊ธฐ์ด๋ฐฉ์ ์ 9
2.1.2 ๊ฒฉ์์ค์ ๊ณผ ์
๋ด์์ ๋ณ์์์น์ ๊ฒฐ์ 12
2.1.3 ๊ธฐ์ด๋ฐฉ์ ์์ ์ด์ฐํ 13
2.1.4 SOLA SCHEME 15
2.2 SOLA-VOF๋ฒ์ ์ํ ์์ ์๋ฉด์ ์ถ์ 19
2.2.1 ์์ ์๋ฉด์ ์์น๊ณ์ฐ์ ์ํ ์ถ์ ๋ชจ๋ธ 19
(1) ์ขํ๊ณ์ ์ํ ๋ฐฉ๋ฒ 19
(2) ์ ์ฒด๋ฉด ์์น์ ์ถ์ ๋ชจ๋ธ์ ์ด์ฉํ ๋ฐฉ๋ฒ 19
(a) Marker์
์์ ์ํ ๋ฐฉ๋ฒ 19
(b) ๋์ดํจ์๋ฅผ ์ด์ฉํ๋ ๋ฐฉ๋ฒ 20
(c) VOF๋ฒ์ ์ํ ๋ฐฉ๋ฒ 20
2.2.2 VOFํจ์์ ์ด๋ฅ๋ฐฉ์ ์ 21
2.2.3 VOFํจ์์ ์ด๋ฅ๋ฐฉ์ ์์ ๋ํ ์ด์ฐํ 21
2.2.4 VOFํจ์์ ์ํ ์์ ์๋ฉด์ ๋ชจ๋ธ๋ง 22
2.2.5 VOFํจ์์ ์ํ ์์ ์๋ฉด์ ํ์ ๋ฐ Cell์ ๋ถ๋ฅ 23
2.2.6 VOFํจ์์ ์์น๊ณ์ฐ 25
2.3 ๊ฒฝ๊ณ์กฐ๊ฑด 33
2.3.1 ์์ ์๋ฉด์์์ ๊ฒฝ๊ณ์กฐ๊ฑด 33
(1) ์ ์๊ฒฝ๊ณ์กฐ๊ฑด 33
(2) ์๋ ฅ๊ฒฝ๊ณ์กฐ๊ฑด 34
2.3.2 ๊ฐ๊ฒฝ๊ณ์กฐ๊ฑด 35
2.3.3 ๊ทธ ์ธ์ ๊ฒฝ๊ณ์กฐ๊ฑด 37
2.4 ์กฐํ์กฐ๊ฑด 38
2.5 ์์ ์กฐ๊ฑด 41
2.6 ์์น๊ณ์ฐ์ ํ๋ฆ 42
์ 3์ฅ ์์นํด์๊ธฐ๋ฒ์ ๊ฒ์ฆ 44
3.1 ์์นํ๋์๋ก๋ด์์ ์กฐํํํ์ ๊ฒ์ฆ 44
3.1.1 ์๊ฐํํ 44
3.1.2 ๊ณต๊ฐํํ 48
3.2 ํด์ ์ง๋ฐ๋ด ์ธต๋ฅ์ ํญ์ ์ํฅ 50
3.2.1 ๊ฐ๊ทน์์ ํ๋ฆ 50
3.2.2 ์ง๋ฐ๋ด์ ์ ์๊ณผ ์๋ ฅ 52
3.2.3 ์ง๋ฐ๋ด์ ์ ์์ด ํ๋์ฅ์ ๋ฏธ์น๋ ์ํฅ 71
3.3 ํใ๊ตฌ์กฐ๋ฌผ์ ์ํธ๊ฐ์ญ 73
3.4 ํใํด์ ์ง๋ฐ์ ์ํธ๊ฐ์ญ 75
3.5 ํใ๊ตฌ์กฐ๋ฌผใํด์ ์ง๋ฐ์ ์ํธ๊ฐ์ญ 77
์ 4์ฅ ํใ์ ์ ใ์ง๋ฐ์ ์ํธ๊ฐ์ญ 83
4.1 ์์นํ๋์๋ก์ ์ ์ 83
4.2 ์ ์ ์ฃผ๋ณ์ ๋น์ ํํ๋๋ณํ ํน์ฑ 84
4.3 ๊ณต๊ฐํ๊ณ ๋ณํ์ ํ๊ท ์์๋ณํ 91
4.4 ์ ์ ์ฃผ๋ณ ๋ฐ ์ง๋ฐ๋ด์ ํ๊ท ์ ์์ฅ 96
4.5 ์ ์ ์ฃผ๋ณ ๋ฐ ์ง๋ฐ๋ด์ ์ต๋๊ฐ๊ทน์์๋ถํฌ 102
4.6 ์ ์ ์ ๋ฉด์์ ๊ฐ๊ทน์์ 107
์ 5์ฅ ํใํผ์ฑ๋ฐฉํ์ ใ์ง๋ฐ์ ์ํธ๊ฐ์ญ 125
5.1 ์์นํ๋์๋ก์ ํผ์ฑ๋ฐฉํ์ 125
5.2 ํผ์ฑ๋ฐฉํ์ ์ฃผ๋ณ์ ๋น์ ํํ๋๋ณํ ํน์ฑ 126
5.3 ๊ณต๊ฐํ๊ณ ๋ณํ์ ํ๊ท ์์๋ณํ 131
5.4 ํผ์ฑ๋ฐฉํ์ ์ฃผ๋ณ ๋ฐ ์ง๋ฐ๋ด ํ๊ท ์ ์์ฅ 136
5.5 ํผ์ฑ๋ฐฉํ์ ์ฃผ๋ณ ๋ฐ ์ง๋ฐ๋ด ์ต๋๊ฐ๊ทน์์๋ถํฌ 143
5.6 ์ผ์ด์จ ๋ฐ ์ฌ์๋ง์ด๋์ ์ ๋ฉด์์ ๊ฐ๊ทน์์ 150
5.6.1 ์ฌ์๋ง์ด๋์ ์ ๋ฉด์์ ๊ฐ๊ทน์์ 150
5.6.2 ์ผ์ด์จ์ ์ ๋ฉด์์ ๊ฐ๊ทน์์ 172
์ 6์ฅ ๊ฒฐ ๋ก 186
6.1 ์์นํด์ 186
6.2 ํด์ ์ง๋ฐ๋ด ์ธต๋ฅ์ ํญ์ ์ํฅ 186
6.3 ํใ์ ์ ใ์ง๋ฐ์ ์ํธ๊ฐ์ญ 187
6.4 ํใํผ์ฑ๋ฐฉํ์ ใ์ง๋ฐ์ ์ํธ๊ฐ์ญ 188
์ฐธ๊ณ ๋ฌธํ 19
์ ์ก๋ฅ๋ญ์ข ์ผ๋ก ์ค์ธ๋ ์ ํ๋์ ๋ฐ์ํ ์ฝ๋ ์คํ ๋กค ์ก์์ข
Cholesterol granuloma is a histopathological diagnosis with features of cholesterol clefts, foreign body giant cells, and macrophages filled with hemosiderin. It is commonly found in the mastoid or petrous apex, but the involvement of paranasal sinuses is very rare. Radiologically, cholesterol granuloma show typical findings of hyperintense signals on both T1- and T2-weighted images on magnetic resonance imaging (MRI). We report two cases of cholesterol granuloma in the sphenoid sinus, which were first misinterpreted as mucoceles due to unusual MRI imagesope
A Case of Extrahepatic Metastasis of Hepatocellular Carcinoma in the Nasal Septum managed with Endoscopic Resection
Metastasis of hepatocellular carcinoma (HCC) in the nasal septum is an extremely rare condition. The proper management and the role of surgical intervention are still controversial and there is no evidence-based guideline for this specific condition. The authors of the present study report a case of HCC with sinonasal metastasis, managed by surgery to relieve nasal obstruction and frequent epistaxis. Complete removal of the tumor via endoscopic surgery was performed and the pathology was reported to be consistent with metastatic HCC. No additional treatment modality was considered for the septal lesion. During the 8-month postoperative period, the patient remained alive and satisfied with comfortable nasal breathing. The present case report stresses the importance of interdisciplinary collaboration. Proper consultation between surgeon and oncologist may lead to improved quality of life, even when the patient is in the terminal stage of HCC.ope
Downregulation of Th17 cells in the small intestine by disruption of gut flora in the absence of retinoic acid.
Retinoic acid (RA), a well-known vitamin A metabolite, mediates inhibition of the IL-6-driven induction of proinflammatory Th17 cells and promotes anti-inflammatory regulatory T cell generation in the presence of TGF-beta, which is mainly regulated by dendritic cells. To directly address the role of RA in Th17/regulatory T cell generation in vivo, we generated vitamin A-deficient (VAD) mice by continuous feeding of a VAD diet beginning in gestation. We found that a VAD diet resulted in significant inhibition of Th17 cell differentiation in the small intestine lamina propria by as early as age 5 wk. Furthermore, this diet resulted in low mRNA expression levels of IL-17, IFN regulatory factor 4, IL-21, IL-22, and IL-23 without alteration of other genes, such as RORgammat, TGF-beta, IL-6, IL-25, and IL-27 in the small intestine ileum. In vitro results of enhanced Th17 induction by VAD dendritic cells did not mirror in vivo results, suggesting the existence of other regulation factors. Interestingly, the VAD diet elicited high levels of mucin MUC2 by goblet cell hyperplasia and subsequently reduced gut microbiome, including segmented filamentous bacteria. Much like wild-type mice, the VAD diet-fed MyD88-/-TRIF-/- mice had significantly fewer IL-17-secreting CD4+ T cells than the control diet-fed MyD88-/-TRIF-/- mice. The results strongly suggest that RA deficiency altered gut microbiome, which in turn inhibited Th17 differentiation in the small intestine lamina propriaope
Geographicย andย demographicย variationsย ofย inhalantย allergenย sensitizationย inย Koreansย andย non-Koreans
BACKGROUND:
To diagnose and treat respiratory allergic diseases, it is important to identify the specific allergens involved. Many differences exist between common inhalant allergens depending on the residential environment and demographic factors. This study aimed to compare common inhalant allergens between Koreans and non-Koreans according to their residential region, age, and sex.
METHODS:
This study evaluated 15,334 individuals who underwent serum tests for multiple allergen-specific immunoglobulin E at a tertiary academic medical center between January 2010 and December 2016. The individuals included 14,786 Koreans and 548 non-Koreans. The AdvanSureโข Allostation assay (LG Life Science, Korea) was used to test for 33 inhalant allergens.
RESULTS:
The house dust mite (HDM) was the most common allergen in both Koreans and non-Koreans, although the proportion of individuals with HDM sensitization was greater among Koreans. High sensitization rates for various pollen types were detected among Koreans in Gangwon region, whereas Japanese cedar pollen was unique among Koreans in Jeju region. Grass pollen and animal dander were relatively common among individuals from the Americas, whereas weed and grass pollen accounted for the 10 most common allergens for individuals from Central Asia. The total sensitization rate, sensitization to HDM, and sensitization to animal dander peaked among adolescents and young adults, then subsequently decreased with age.
CONCLUSIONS:
This large-scale study demonstrates that various regional and age-related differences exist in the allergen sensitization rates of Koreans and non-Koreans. These data could be useful for development of avoidance measures, immunotherapy for causative allergens, and policymaking regarding allergic diseases.ope
Essays on Climate Change Computable General Equilibrium Models
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ผ๋ฌธ (๋ฐ์ฌ)-- ์์ธ๋ํ๊ต ํ๊ฒฝ๋ํ์ : ํ๊ฒฝ๊ณํํ๊ณผ, 2013. 8. ํ์ข
ํธ.This research reviews the problems of conventional computable general equilibrium (CGE) models which are widely used for climate change policy analysis. To solve the problems, it proposes multivariate distribution approach as an alternative way of representing the production activities in model structures and assesses the possibility of its practical employment.
In the first part of this research, the basic characteristics of three well known global CGE models are reviewed and production function structures are pointed out as the main sources of the differences in carbon emission projections among models. Two experiments are introduced regarding the effects of changes in production function structures. In one experiment, the nested structure of constant elasticity substitution (CES) functions is substituting with alternative nesting structures. In another experiment, fixed input structures are partly applied for incorporating bottom-up approach with top-down mechanism of CGE models. The results show that these structural changes cause a considerable impact on the prediction results of greenhouse gas emissions and carbon prices. Also, the experiments are extended to the comparison of GDP losses among different model structures. Simulations for the case of Korea reveal that the estimations of GDP loss differs among model structures, raising some issues on applying them into practical policy making.
In the second part, the performance of a global CGE model is analyzed in marginal abatement cost estimation when data disaggregation is applied. Extraordinary carbon prices are reported for the case of relatively large share of capital in the economies of a few developing countries. Empirical evidence indicates that the abnormal phenomenon is accounted for by the proportional relationship between capital intensity and carbon price. The analysis is extended to CES functions with a numerical analysis, concluding that the unusual phenomena may be connected to distribution parameters of CES functional forms which are most widely used in CGE models.
In the last part, multivariate distribution approach is applied for an alternative description of energy related production activities. Applying theories on the microfoundations of aggregate production functions, it is shown that a set of bottom-up microscopic information can converge to specific aggregate production functions if assumptions are imposed on the statistical distribution of local production technologies. The actual characteristics of statistical distributions were reviewed for a real dataset of energy intensive manufacturing sector of Korea. To facilitate simulations and conveniently reproduce the relationships embedded in multivariate joint distribution maps, a statistical tool called copulas is introduced in advance. After the basic theory of copulas is briefly introduced, the performance of a copula model is investigated, revealing that a copula model is successful in describing heterogeneous microscopic information. After the introduction of copulas, a new type of CGE model is applied, in which an aggregation of local Leontief production functions takes over the role of conventional global production functions. A pilot model is composed to apply this scheme to a CGE model and it is shown that this new approach has some advantages: it eliminates the effect of the past time data and improves the precision of projection results.Table of Contents
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
I. Overall introduction . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Motivations . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Overview and outline . . . . . . . . . . . . . . . . . . . . . 3
1.3 Contributions . . . . . . . . . . . . . . . . . . . . . . . . . 6
II. Structural differences between global climate change CGE models. . . . . 9
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2 Reviews on global CGE models . . . . . . . . . . . . . . . 14
2.2.1 Models . . . . . . . . . . . . . . . . . . . . . . . . 16
2.2.2 Static structure . . . . . . . . . . . . . . . . . . . . 18
2.2.3 Dynamic process . . . . . . . . . . . . . . . . . . . 25
2.3 Model structure analysis . . . . . . . . . . . . . . . . . . . 27
2.3.1 Change in energy-capital bundle structures . . . . . 29
2.3.2 Replacement with fixed input structures . . . . . . . 36
2.4 Policy implications . . . . . . . . . . . . . . . . . . . . . . 43
2.4.1 Carbon price . . . . . . . . . . . . . . . . . . . . . 43
2.4.2 Estimation of GDP change . . . . . . . . . . . . . . 46
2.5 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . 48
III. Carbon prices and parameter calibration in CES function structures. . . 51
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 51
3.2 Problems in regional disaggregation . . . . . . . . . . . . . 54
3.2.1 Derivation of MACC using the EPPA model . . . . . 54
3.2.2 Regional deviations in carbon price . . . . . . . . . 61
3.3 Mathematical analysis . . . . . . . . . . . . . . . . . . . . 67
3.3.1 Ratio of capital intensity . . . . . . . . . . . . . . . 67
3.3.2 Extensions to the CES function . . . . . . . . . . . 74
3.4 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . 78
IV. The statistical distribution approach for a description of production activities . . 81
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 81
4.2 Functional forms and data distribution . . . . . . . . . . . . 87
4.2.1 Microfoundations of production functions . . . . . . 87
4.2.2 Data analysis . . . . . . . . . . . . . . . . . . . . . 96
4.2.3 Dependence representation of the CES function . . . 103
4.3 The copula model . . . . . . . . . . . . . . . . . . . . . . . 106
4.3.1 Copula theory . . . . . . . . . . . . . . . . . . . . . 107
4.3.2 Construction of a copula model . . . . . . . . . . . 109
4.3.3 Performance of the copula model . . . . . . . . . . 113
4.3.4 The copula model with data disaggregation . . . . . 119
4.4 The statistical distribution approach . . . . . . . . . . . . . 128
4.4.1 Set of firms . . . . . . . . . . . . . . . . . . . . . . 128
4.4.2 Properties of cost functions . . . . . . . . . . . . . . 131
4.4.3 Elasticity of substitution . . . . . . . . . . . . . . . 137
4.5 Application of the distribution approach to CGE models . . 144
4.5.1 The pilot CGE model . . . . . . . . . . . . . . . . . 144
4.5.2 Projection results . . . . . . . . . . . . . . . . . . . 148
4.6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . 154
Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Appendices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
I. The structure of the pilot CGE model . . . . . . . . . . . . . 171
II. Source code . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185Docto
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