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1.
An imbalance between helper T cell type 1 (Th1) and helper T cell type 2 (Th2) activation can result in immunodysregulations leading to impaired cell-mediated immunity with an increased incidence of infectious disease or cancer and/or aberrant humoral immunity that may culminate with an autoimmune disease. Mercury, a heavy-metal toxicant, is known to induce renal autoimmunity characterized by a predominant Th2 response. Lead, another metal toxicant, causes enhanced B cell activities and impairs host resistance to several bacterial and viral infections. In addition, Pb was reported to enhance Th2 proliferation and inhibit Th1 proliferation. The differential effects of Pb on Th subset activation have been further investigated. In vitro IL-4 production by a Th2 clone was significantly increased by the addition of PbCl2, whereas IFN gamma production by a Th1 clone was decreased by the addition of PbCl2. When BALB/c mice were subcutaneously exposed to PbCl2, ex vivo Il-4 production by anti-CD3-stimulated splenic T cells was enhanced, but IFN gamma production was inhibited. Additionally, the plasma IL-4 and IgE levels of Pb-exposed mice were increased, and the plasma IFN gamma levels were significantly lowered in the absence of any additional exogenous antigen. In vitro, ex vivo, and in vivo treatment with HgCl2 produced similar findings. This study is the first report of the preferential activation of a Th2 response by Pb in vivo and suggests that PB, like Hg, may induce autoimmune responses by upsetting the balance between Th1- and Th2-like cells, which could enhance production of antibodies to self antigens. 相似文献
2.
Zone 3 of a distance relay is used to provide the remote backup protection in case of the failure of the primary protection. However, the risk of maloperation under stressed conditions such as heavy loading, voltage, and transient instability is quite high. Zone 3 is used in combination with the derivatives of the voltage and current, etc. to prevent maloperation. At times, the impedance characteristics that restrict the tripping area of relay are used to avoid maloperation due to load encroachment. This work presents a novel zone 3 scheme based on combining the steady-state components (i.e., 60 Hz) and the transient components (TCs) using a state diagram that visualizes the sequence of studies that emanate from the sequence of events. The simulation results show that the novel zone 3 distance relay elements using the proposed method operate correctly for the various events. 相似文献
3.
Han-Jun Oh Jong-Ho Lee Hong-Joo Ahn Yongsoo Jeong Chang-Hoe Heo Choong-Soo Chi 《Journal of Electroceramics》2006,17(2-4):369-373
The characteristics and growth behaviors of alumina dielectric layer formed by anodic oxidation were investigated. The aluminum oxide layer anodized at 400 V was predominantly amorphous alumina, but at the applied potentials more than 500 V, amorphous and crystalline γ-alumina were existed in anodic oxide layer and the ratio of γ-alumina increased with the increasing applied potential. During the heat treatment at 600°C or higher temperature, amorphous alumina layer was transformed into the crystalline γ-alumina. The phase transition of anodic amorphous alumina into crystalline depends on anodic applied potentials and heat-treatment temperatures. 相似文献
4.
Jung-Ho Song Jung-Woo Park Eun-Deok Sim Yongsoon Baek 《Photonics Technology Letters, IEEE》2005,17(9):1791-1793
Amplified spontaneous emission (ASE) spectra of passive waveguide integrated lasers have been studied to estimate the coupling efficiency and the reflectivity at the butt-joints between active and passive waveguides. A new method has been proposed for the analysis of ASE to extract the coupling efficiency and reflectivity at the butt-joints. This method was applied experimentally to estimate the coupling and reflection of the passive waveguide integrated lasers with different amounts of vertical misalignments of active and passive waveguides. 相似文献
5.
Tae Geun Kim Kyung Hyun Park Sung-Min Hwang Yong Kim Eun Kyu Kim Suk-Ki Min Si-Jeong Leem Jong-Il Jeon Jung-Ho Park Chang W.S.C. 《Quantum Electronics, IEEE Journal of》1998,34(8):1461-1468
GaAs-AlGaAs V-grooved inner stripe (VIS) quantum-well wire (QWW) lasers grown by metalorganic chemical vapor deposition with different current blocking configurations, n-blocking on p-substrate (VIPS), p-n-p-n blocking on n-substrate (VI(PN)nS) and p-blocking on n-substrate (VINS) have been fabricated and characterized. The VIPS QWW lasers show the most stable characteristics with effective current confinement: one of the lasers shows fundamental transverse mode, lasing up to 5 mW/facet, typical threshold current of 39.9 mA at 818.5 mm, an external differential quantum efficiency of 24%/facet, and characteristic temperature of 92 K. The current tuning rate was almost linear at 0.031 mm/mA, and the temperature tuning rate was measured to be 0.14 nm/°C. Comparison of the light output versus current characteristics of the lasers with different current blocking configurations is presented here 相似文献
6.
Kyeong-Sik Shin Kyeong-Kap Paek Jung-Ho Park Tae-Song Kim Byeong-Kwon Ju Ji Yoon Kang 《Electron Device Letters, IEEE》2007,28(7):581-583
In this letter, we examined whether the parasitic bipolar junction transistors (BJTs) in the MOSFET fabricated by the standard CMOS process can play a role as a fluorescence detector. To suppress the action of two vertical parasitic BJTs, the gate and n-well were tied in the parasitic BJTs, and the body node was connected to the drain. The proposed device was compared with the inherent and the parasitic diodes in the MOSFET. It had 100 times higher photocurrents than the diodes in the MOSFET. In addition, it was applied for the detection of the fluorescent signal, and could detect near 10 nM of Alexa 546. Therefore, CMOS-process-compatible parasitic BJTs can be used as a photodetector in an integrated fluorescence detector. 相似文献
7.
Jung-Ho Um Yong-Ki Kim Hyun-Jo Lee Miyoung Jang Jae-Woo Chang 《Journal of Systems Architecture》2012,58(9):354-371
Due to the advancement of wireless internet and mobile positioning technology, the application of location-based services (LBSs) has become popular for mobile users. Since users have to send their exact locations to obtain the service, it may lead to several privacy threats. To solve this problem, a cloaking method has been proposed to blur users’ exact locations into a cloaked spatial region with a required privacy threshold (k). With the cloaked region, an LBS server can carry out a k-nearest neighbor (k-NN) search algorithm. Some recent studies have proposed methods to search k-nearest POIs while protecting a user’s privacy. However, they have at least one major problem, such as inefficiency on query processing or low precision of retrieved result. To resolve these problems, in this paper, we propose a novel k-NN query processing algorithm for a cloaking region to satisfy both requirements of fast query processing time and high precision of the retrieved result. To achieve fast query processing time, we propose a new pruning technique based on a 2D-coodinate scheme. In addition, we make use of a Voronoi diagram for retrieving the nearest POIs efficiently. To satisfy the requirement of high precision of the retrieved result, we guarantee that our k-NN query processing algorithm always contains the exact set of k nearest neighbors. Our performance analysis shows that our algorithm achieves better performance in terms of query processing time and the number of candidate POIs compared with other algorithms. 相似文献
8.
Yeong-Kyeun Paek Jung-Ho Ahn Gyeung-Ho Kim Suk-Joong L. Kang 《Journal of the American Ceramic Society》2002,85(6):1631-1633
The densification behavior of a 3-mol%-Y2 O3 -doped ZrO2 (3Y-ZrO2 ) has been investigated under N2 and O2 atmospheres. Powder compacts have been sintered at 1550° and 1400°C for various times. The density of the specimen sintered at 1550°C is higher in N2 than in O2 , while the contrary result is obtained in the case of the specimen sintered at 1400°C. Such results can be explained in terms of nitrogen solubility and oxygen vacancy in a ZrO2 matrix. Because nitrogen solubility into the ZrO2 increases with an increase in heat-treatment temperature, leading to the formation of oxygen vacancy, the densification rate becomes higher. The present study thus shows evidence of nitrogen solubility into the ZrO2 and its role on the densification behavior of 3Y-ZrO2 . 相似文献
9.
Emission properties and energy transfer of PbO–Bi2 O3 –Ga2 O3 –GeO2 glasses codoped with Tm3+ and Tb3+ ions were investigated. The 1.48-μm emission due to the Tm3+ :3 H4 →3 F4 transition can be used to amplify the S-band (1460–1530-nm) signal light. With Tb3+ addition, the lifetime and emission intensity of the Tm3+ :3 F4 level decreased sharply via the Tm3+ :3 F4 →Tb3+ :7 F0,1,2 energy transfer. Population densities of the 3 F4 and 3 H4 levels in Tm3+ calculated from rate equations clearly verified that population inversion in Tm3+ ions became possible with as little as 0.1 mol% of Tb3+ addition. 相似文献
10.
Kim Jeongeun Kim Sukwha Kim Seongheui Lee Euehun Heo Yoonjeong Hwang Cheol-Yong Choi Yun-Young Kong Hyoun-Joong Ryu Hyeongju Lee Hyeongsuk 《Intelligent Service Robotics》2021,14(5):729-739
Intelligent Service Robotics - This study aims to analyze the concept of companion robots for older adults from the perspective of nursing. This study employed a concept analysis. The literature... 相似文献