Tinghua University

Beijing, China

Tinghua University

Beijing, China
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Lin W.,Peking Union Medical College | Jin L.,Tinghua University | Chen H.,Peking Union Medical College | Wu Q.,Peking Union Medical College | And 9 more authors.
Arthritis Research and Therapy | Year: 2014

Introduction: IgG4-related disease (IgG4-RD) is a multisystem-involved autoimmune disease. Abnormally activated and differentiated B cells may play important roles. Regulatory B cells (Breg) are newly defined B cell subgroups with immunosuppressive functions. In this study, we investigated the differences of B cell subsets, the expressions of co-stimulatory molecules on B cells, and the function of Breg cells in patients with IgG4-RD, primary Sjögren's syndrome (pSS) as well as in healthy controls (HC).Methods: Newly diagnosed IgG4-RD patients (n = 48) were enrolled, 38 untreated pSS patients and 30 healthy volunteers were recruited as disease and healthy controls. To analyze B cell subsets and B cell activity, PBMCs were surface stained and detected by flow cytometry. The function of Breg cells was tested by coculturing isolated CD19 + CD24hiCD38hi Breg cells with purified CD4 + CD25- T cells. Serum cytokines were measured by ELISA and cytometric bead array. Relationship between clinical data and laboratory findings were analyzed as well.Results: Compared with pSS patients and HC, IgG4-RD patients had a lower frequency of peripheral Breg cells. Interestingly, CD19 + CD24-CD38hi B cell subsets were significantly higher in peripheral B cells from IgG4-RD patients than in pSS patients and HC, which correlated with serum IgG4 levels. The expression of BAFF-R and CD40 on B cells was significantly lower in IgG4-RD patients compared with those in pSS patients and HC. Unlike HC, Breg cells from pSS patients lacked suppressive functions.Conclusions: B cells in patients with IgG4-RD and pSS display a variety of abnormalities, including disturbed B cell subpopulations, abnormal expression of key signaling molecules, co-stimulatory molecules, and inflammatory cytokines. In addition, a significantly increased B cell subset, CD19 + CD24-CD38hi B cells, may play an important role in the pathogenesis of IgG4-RD. © 2014 Lin et al.; licensee BioMed Central Ltd.

Li Q.,Tinghua University | Li Q.,Nuclear Power Institute of China | Jiao Y.,Nuclear Power Institute of China | Chen J.,Nuclear Power Institute of China | And 2 more authors.
International Conference on Nuclear Engineering, Proceedings, ICONE | Year: 2015

Spacer grid is an important component in PWR fuel assemblies for its significant influence on thermal-hydraulic characteristics of the reactor core. In this study, single-phase CFD technology is used to study the flow and resistance in a 5×5 rod bundle with spacer grid. CFX 12 is chosen as the tool software. The geometries of spacer grid and rod bundle are finished by UG code. To simulate the contact of springs and dimples with fuel rods, small gaskets are induced. The SST model is chosen for turbulent simulation. The results of resistance coefficients including both local loss coefficients and frictional loss coefficients under different Re numbers are conformed well to the experiment. The agreement of calculated liquid velocity distribution downstream the spacer grid with the experiment is also well but less satisfactory. We draw attention to the influence of mixing vanes and find that mixing vanes are the main components that induce the lateral flow, but take up little percents in the local loss coefficient of spacer grid. The lateral flow caused by mixing vanes will increase the frictional loss coefficient downstream the spacer grid. These results are beneficial to the optimization design of spacer grid. Copyright © 2015 by JSME.

Xu W.,Ryerson University | Liu L.,University of Waterloo | Liu L.,Tinghua University | Zhou Y.,University of Waterloo | And 2 more authors.
Materials Science and Engineering A | Year: 2013

The microstructures, tensile and fatigue properties of weld-bonded (WB) AZ31B-H24 Mg/Mg joints with different sizes of bonding area were evaluated and compared with the adhesive-bonded (AB) Mg/Mg joints. Typical equiaxed dendritic structures containing divorced eutectic Mg17Al12 particles formed in the fusion zone of both WB-1 (with a bonding area of 35mm×35mm) and WB-0.5 (with a bonding area of 17.5mm×35mm) joints. Less solidification shrinkage cracking was observed in the WB-0.5 joints than WB-1 joints. While the WB-0.5 joints exhibited a slightly lower maximum tensile shear stress than the AB-0.5 joints (with a bonding area of 17.5mm×35mm), the energy absorption was equivalent. Although the AB-0.5 joints exhibited a higher fatigue resistance at higher cyclic stress levels, both the AB-0.5 and WB-0.5 joints showed an equivalent fatigue resistance at lower cyclic stress levels. A higher fatigue limit was observed in the WB-0.5 joints than in the WB-1 joints owing to the presence of fewer shrinkage pores. Cohesive failure mode along the adhesive layer in conjunction with partial nugget pull-out from the weld was observed at the higher cyclic loads, and fatigue failure occurred in the base metal at the lower cyclic loads. © 2012 Elsevier B.V.

Zeng W.,Huazhong University of Science and Technology | Zou S.,Tinghua University | Zuo H.,Beijing Institute of Technology
Lecture Notes in Electrical Engineering | Year: 2015

Functional magnetic resonance imaging (FMRI) has been widely used in the field of medicine and physiology, which realizes neuro imaging without damage. FMRI was initially applied to the analysis of FMRI images; however, its statistical analysis was limited to the elementary processes because of the complexities of the FMRI images and the difficulties to establish the neuromotor time–space model. In this chapter, we focus on the analysis of FMRI images based on large data. Firstly, we make the time-correlation analysis of the data to reduce the size of the data. Then, we further investigate the spatial characteristics of valid signals, and compare the predicted signal and the original signal in the time domain and frequency domain. We find that there is a strong relevance of FMRI data in both time and space area, which indicates that the stimulation signal of the brain radiates to the surroundings of the stimulated point, and the signal is continuous in time, not an impulse. © Springer International Publishing Switzerland 2015.

Guo Y.-N.,China University of Mining and Technology | Zhang S.,China University of Mining and Technology | Cheng J.,China University of Mining and Technology | Cheng J.,Tinghua University | Lin Y.,China University of Mining and Technology
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

In cooperative interactive genetic algorithms, each user evaluates all individuals in every generation through human-machine interface, which makes users tired. So population size and generation are limited. That means nobody can evaluate all individuals in search space, which leads to the deviation between the users' best-liked individual and the optimal one by the evolution. In order to speed up the convergence, implicit knowledge denoting users' preference is extracted and utilized to induce the evolution. In the paper, users having similar preference are further divided into a group by K-means clustering method so as to share knowledge and exchange information each other. We call the group as knowledge alliance. The users included in a knowledge alliance vary dynamically while their preferences are changed. Taken a fashion evolutionary design system as example, simulation results show that the algorithm speeds up the convergence and decreases the number of individuals evaluated by users. This can effectively alleviate users' fatigue. © 2011 Springer-Verlag.

Li K.,China Academy of Safety Science and Technology | Li K.,Tinghua University | Ding C.,China Academy of Safety Science and Technology | Ding C.,China University of Mining and Technology | You C.,Tinghua University
Procedia Engineering | Year: 2011

The ventilation tube was an important equipment in tunnels. Although the ventilation tube used in most coal mines was hard to ignite, it can be destroyed by fires. Based on numerical simulation methods, the influence of ventilation tube rupture locations on gas distribution has been investigated when fires happen. The results show that when the ventilation tube ruptured, the flow rate of the ventilation tube increased as the distance between the rupture location and the tunnel end increasing. In addition, when the distance increased to a certain value, "the second vortex" appears but its scale decreased as the fire intensity increasing. When at the same rupture location, the maximum gas concentration increased first and then decreased as the fire intensity increasing. When the ventilation tube ruptured, the coal gas distribution shows an "up-down" -"left-right"-"uniform" pattern from the tunnel end to the outlet, and whether the second vortex appeared or not is a critical factor on deciding the detailed gas distribution in the former part of the tunnel. © 2011 Published by Elsevier Ltd.

Li K.,China Academy of Safety Science and Technology | Li K.,Tinghua University | Ding C.,China Academy of Safety Science and Technology | Ding C.,China University of Mining and Technology | You C.-F.,Tinghua University
Procedia Engineering | Year: 2011

Based on the 3-D tunnel model, the influence of ventilation tube rupture, its locations and the draught fan stopping working on second catastrophes has been investigated when fires happen. The results show that when the ventilation tube ruptured, "the second vortex" appears and the gas concentration shows "up-down" -"left-right"-uniform distribution from the tunnel end to the outlet. When the tube broken position is larger than 30 m, the volume where the gas concentration is between 5%∼16% increases first and then decreases as the fire intensity increases and it reaches to its maximum value when the fire intensity equals to 400 kW. But due to low temperature, this will not induce to gas explosion. The coal gas and smoke show an evident layered distribution and concentration on the tunnel roof after the fan shut down. When fire intensity is 1200 kW, gas explosion will not happen but the secondary catastrophes will appear when the fire intensity is further increased. © 2011 Published by Elsevier Ltd.

Zhong Y.,Tinghua University | Zhong Y.,Chinese Ministry of Water Resources | Liu H.,China Institute of Water Resources and Hydropower Research | Tian F.,Tinghua University | Lin M.,Central University of Finance and Economics
Shuili Xuebao/Journal of Hydraulic Engineering | Year: 2016

In the context of population growth and climate change, the scarcity of water resources has being more prominent, making development and utilization of transboundary river an internationally and regionally sensitive and intractable problem. The competition over transboundary river water resources is a "Prisoner Dilemma" situation. This paper explored the way of applying reciprocity theory on untacking Prisoner Dilemma in transboundary river cooperation, and discussed its feasibility and prerequisites. The case of Nile River in Africa was studied to analyze the challenges in transboundary river cooperation, and then the way towards evolution of cooperation was proposed. The Columbia River in North America was taken to exemplify the way towards evolution of cooperation on transboundary river cooperation. The results show that reasonable exploitation of transboundary river could not only increase common benefit of upstream and downstream states, but also promote the evolution of international cooperation in political and economic areas. Successful practice of reciprocity theory provides reference for cooperation policy making in water resources area between China and neighboring countries. © 2016, China Water Power Press. All right reserved.

Cherkashin A.P.,Russian Academy of Sciences | Zhao H.,Tinghua University | Kolesnikov S.S.,Russian Academy of Sciences
Biologicheskie Membrany | Year: 2015

The taste bud is composed of tightly packed 50-100 cells. Since a distance between taste bud cells is much smaller that the characteristic cell size, extracellular volume is lesser than that of the cytoplasm by at least two orders of magnitude. By that, electrical activity of taste bud cells, which is associated with redistribution of physiologically important ions between the cell cytoplasm and external medium, can entail substantial variations of extracellular ions, including Ca2+. In a heterogeneous population of taste bud cells that includes several cellular subtypes, voltage-gated (VG) Ca2+ channels are functional solely in taste cells of the type III. Here we analyzed how VG Ca2+ currents in these cells depended on a concentration of bath Ca2+. As was found, the VG Ca2+ current rose with external Ca2+ nonmonotonically but exhibited a plateau at certain concentrations of the carrier. This pointed at the existence of a regulatory mechanism enabling VG Ca2+ channels to mediate nearly invariable Ca2+ influx in a physiologically relevant range of concentrations of bath Ca2+ irrespective of its variability. The mathematical model was proposed, wherein extracellular Ca2+-sensing receptor (CASR) was hypothesized to monitor extracellular Ca2+ and to properly adjust activity of VG Ca2+ channels. Thus, external Ca2+ determines a VG Ca2+ current directly as a carrier and indirectly as a CASR agonist. With certain parameters, the model nicely simulated the experimental dependence of the VG Ca2+ current in type II cells on bath Ca2+.

Jin Z.,Tinghua University | Tianshu W.,Tinghua University
Journal of Spacecraft and Rockets | Year: 2013

The solar sail is a new type of spacecraft for deep space exploration that is propelled by solar radiation pressure. The solar sail is large, has a large moment of inertia, and is highly flexible, and its motion involves a coupling of the orbit, the attitude, and structural vibration. With the coupling effect of the orbit and the attitude included, a non-Keplarian displaced solar orbit is designed. In the rotating frame, the solar sail has a stable equilibrium point, and an attitude controller is employed for coupled attitude-orbit control. With control, the time required for eliminating the orbital deflection is much larger than that required for the attitude deflection. Including the additional influence of the flexibility of the solar sail, the structure shows a sustained, high-frequency vibration, which also leads to sustained and high-frequency likewise small vibrations of the orbit and attitude. This work demonstrates the importance of including the structural flexibility into the coupling effect of the solar sail for long-term missions in space. Copyright © 2012 by the American Institute of Aeronautics and Astronautics, Inc.

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