bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on Brown Coal Pyrolysis
Authors: Zhao Gang Wei , Xiao Yun Han
Published: June 2012

It is very important to the combustion processes of coal pyrolysis, so the effects of all reaction condition on the brown coal (Yunnan,China) were investigated by using the fixed bed reactor in detail. Through the new method of part-hydrogenation of the pyrolysis, it can be increased the content of coal tar at the same time reduced H2consumption.
Synthesis of Sialon-Based Eco-Materials from Gold Mineral Tailings
Authors: Hao Hong Shun , Wang Hui Li , Lian Fang , Liu Gui Shan , Hu Zhi Qiang , Xu Li Hua
Published: June 2012

Sialon-based eco-materials were synthesized by using the gold mineral tailings that containing abundant Si and Al elements as the major raw material with minor additives through the carbothermal reduction nitridation route. This study realized the conversion of eco-materials from solid waste, gold mineral tailings. The effects of sintering temperature, holding time and x value during carbothermal reduction nitridation process on the phase composition and microstructure of as-fabricated Sialon-based materials were explored. The XRD results indicated that when sintering temperature is 1550°C, holding time is 6h, and x value is 1.0, Ca-α-Sialon/SiC/Fe3Si composites was successfully synthesized. The relative contentSubscript textof each phase in the products is I(α-Sialon): I(SiC): I(Fe3Si)=82:10:8. The SEM images showed the densificated microstructure and uniform grains with the long column shape.
Monte Carlo Simulation of Alpha (α) Particles Penetration in Nanoscale Silicon Semiconductor Materials
Authors: Amir Haider F. Abdul , Chee Fuei Pien
Published: June 2012

Microsystems, both in space and ground level, will use systems with III-V semiconductors and devices of nanoscale. Vulnerability of this system towards the radiations warrants extra care to be taken. Therefore, appropriate test and analysis to assure the hardness (radiation resistance) of components to be used in various radiation environments is necessary. In this paper, the defect generated in the interaction of alpha (α) particles and silicon (Si) semiconductor material is simulated using SRIM (Stopping and Range of Ions in Matter). The induced defects are in the form of vacancies, defect clusters and dislocations. Besides, the defect is found influencing the kinetic processes that occur both inside and outside the cascade volume. The radiation tolerance between the conventional scale and nanoscale thickness of silicon layer is also being compared. From the findings, it is observed that when the thickness of silicon layer is scaled down, defect that induced by the energy deposition of -particles is significantly lesser. This means that nanoscale silicon layer features improved radiation robustness towards the deposition of energetic ions.
Heterodyne Laser Doppler Radar Based on Er-Doped Fiber Laser
Authors: Ma Zong Feng
Published: June 2012

A low-cost, novel and robust heterodyne laser Doppler radar based on Er-doped fiber laser is presented in this paper. Reliable optical fiber components and instruments for the optical communication were used to build this system. All devices of optical circuit are connected by single-mode fibers making the system reliable and setup arrangement flexible. Spectrum estimation methods based on an efficient digital signal processing technique, fast Fourier transformation (FFT), was utilized to determine the location of the peak. Experiments were performed on a moving hard target with this developed prototype. The results are presented: the minimum velocity can be measured is below 0.5mm/s, and the resultant nonlinear of the measured curve calculated by least square method is below 100 ppm.
Characteristics of Femtosecond Laser Interaction with the Two-Level Atom System in Optical Materials
Authors: Peng Yu Feng , Pan Xiao Li , Meng De Wen , Peng Fang
Published: June 2012

With the development of laser technology, the femtosecond laser has been more and more extensively used both on scientific research and practical application. The interaction of femtosecond laser with two-level atoms in optical materials was discussed. The evolution of femtosecond pulse in resonant atomic medium with long distance, and the influence of the distribution of the laser field amplitude, which were Gaussian, hyperbolic secant, and asymmetric hyperbolic secant, on the two-level atomic transition probability is presented. Also the dynamic analysis of temporal evolution of atomic transition in a two-level system under the radiation of the frequency-chirped field in optical materials is analyzed.
Application of Numerical Simulation and Optimization on Tensioner Pulley Bracket
Authors: Nan Hong Yan , Chen Li Lin , Mi Guo Fa , Ma Jiao
Published: June 2012

This article is about casting process of tensioner pulley bracket, which includes solidification simulation, mould filling simulation and defect forecast, using ViewCast software. The scale and location of the shrinkage defects were shown in simulation results. Solidification results demonstrated that the casting defects were not eliminated by the casting technology. The optimized scheme was obtained by replacing and adding chills. The optimization scheme was calculated and the simulation results shown that the reasonable casting process was obtained and the process has been proofed by the productive practice.
Free Vibration Analysis of Plates on Winkler Elastic Foundation by Boundary Element Method
Authors: Zhang Guang Peng , Zou Tian Xia , Sang Yao Hui , Kang Ning
Published: June 2012

Plates are widely used in the machine tool structure. Based on the differential equations of flexural free vibration of a thin plate on Winkler elastic foundation, its dynamic fundamental solutions and the dynamic boundary integral equations are established. The solving methods of the corner point problems are given out. The quadratic elements are used to discretize the boundary integral equations and the receptance mtrix equations of a thin plate on Winkler elastic foundation are established. The fequency scanning method is used to obtain the natural frequencies of the thin plate on Winkler elastic foundation. Case studies showed the effectiveness of the proposed BEM dynamical analysis, which can be also used in the dymical analysis of joints in a machine tool structure.
Human Ear Recognition Using Hybrid Filter and Supervised Locality Preserving Projection
Authors: Lei Song Ze , Zhu Qiang
Published: June 2012

To solve the difficult problem of human ear recognition caused by variety of ear angle, a novel method which combines hybrid filter with supervised locality preserving projection (SLPP) is proposed. The ear image is firstly filtered by Log-Gabor filter which is constructed with 5 scales and 8 orientations. The important parameters of Log-Gabor filter are selected through experiments. To form effective and discriminative feature too many Log-Gabor coefficients are reduced by discrete cosine transform. Lastly feature is constructed by SLPP to discovery geometrical rules. Experimental results show that compared with the traditional methods, the proposed method obtains higher recognition rate, and is robust to multi-pose of ear recognition.
Temperature/Humidity Control System Based on Micro Controller Unit in the Room of Bikram's Yoga
Authors: Li Na , Tang Yong Gang , Wang Gui Ying
Published: June 2012

This thesis has designed a temperature/humidity remote system which takes Micro controller Unit AT89S51 as the core control unit. The system consists of Micro controller Unit, SHT75 temperature/humidity sensor, Rok 101 007 wireless transceiver and PC data display modules. The system can detect and control temperature/humidity in the room of Bikram's yuga remotely to create an environment suitable for fitness in high temperature.
Reducibility of Oxide-Ion Conductors La2Mo2-Ywyo9
Authors: Li Dan , Li Xiang Hu
Published: June 2012

The reducibility of oxide-ion conductors La2Mo2-Ywyo9(y=0, 0.1) were studied in the reducing atmosphere of 5%H2+Ar by means of impedance spectroscopy measurement. 5% W-doped La2Mo2-Ywyo9can enhance the conductivity and improve the reducibility in the temperature range from 275oC to 650oC.
Experiment Study on Mechanical Performance of Shale Lightweight Aggregate Concrete
Authors: Li Lin , Wang Qing , Wang Yu , Ding Zhao Yang
Published: June 2012

High performance lightweight aggregate concrete is a kind of lightweight environment-protected building material with high strength, good workability, volume stability and durability, which is widely used in large scale engineering and some important engineering. In this paper water-binder ratio, fly ash content, pre-wetting time, sand ratio were tested to explore the comprehensive strength of lightweight aggregate concrete(LWAC). SEM was used to observe the microstructure characteristics of the specimens. The results showed that LWAC produced in the experiment present good performance, whose apparent density was 1760 Kg/m3～1930Kg/m3, 28d compressive strength was 55MPa～60MPa. Reasonable amounts of sand ratio(38%) and mineral admixtures(10%) were exited and the self-strength of lightweight aggregate played an important role in the preparation of LWAC. In the meanwhile, lightweight aggregates which were pre-wetted effectively increased the later strength.
Influence of Ar Pressure on the Structure and Electrical Properties of TiO2 Nanofilm Materials
Authors: Zhan Li Lin , Wang Ying Lian
Published: June 2012

Highly conductive and transparent TiO2 nano films have been deposited by R.F. magnetron sputtering method on glass substrates. The influence of argon gas pressure on deposition rate, electrical performance and surface morphology has been studied through the ellipsometric thickness gauge, scanning electron microscopy and energy disperse spectroscopy. The results show that, with the rise of argon gas pressure, the deposition rate reduces, resistivity decreases, roughness increases. When Ar pressure is 3.0Pa, the resistivity reached 3.3×105Ω•cm, sputtering pressure is lower, the surface atomic diffusion capacity is stronger, the film is more dence.
Ag–Loaded Polypyrrole/Carbon Nanotube: One-Step In Situ Polymerization and Improved Capacitance
Authors: Mi Hong Yu , Xu You Long
Published: June 2012

Ternary composites of Ag–loaded polypyrrole/carbon nanotube (Ag–PPy/CNT) are prepared using a one–step in situ polymerization. Ag nanoparticles are uniformly decorated on the core–shell PPy/CNT networks. This approach provides a simple, easily accessible strategy for preparing three–dimensional noble metal–conductive polymer–carbon nanotube composites. Electrochemical properties of Ag–loaded composites are evaluated to understand the effect of Ag on the structure and kinetic process of the composite. Results indicate that the composites have good electrochemical reversibility and high specific capacitance. The specific capacitiance of Ag–PPy/CNT composites are enhanced greatly from 206.7 F g–1 of PPy/CNT composites to 528.6 F g–1 at 3 mA cm–2. This demonstrates that combining nano–sized Ag with supercapacitor materials is very effective in promoting electrochemical performance of materials.
Improvement of Japanese JAC Wafer Acid Etcher
Authors: Jin Li Hui , Wang Guo Rui , Li Xiang
Published: June 2012

As fast development of semiconductor industry，equipment using PLC as main control unit has been widely used. Wafer chemical etching machine based on PLC control technology has some unreasonable design, causing the low process efficiency. After electronic control system upgrade, UPH is to increase 220%, water consumption is to decrease 39% and power consumption is to decrease 69%.
Characteristics of CAS and Bi-Based Glass Frit as the Inorganic Binder of Alumina Insulation Slurry
Authors: Wang Zheng , Jiang Dan Yu , Feng Tao , Xia Jin Feng
Published: June 2012

In this study,we prepared two kinds of glass frits include CAS and Bi-based glass frit as inorganic binders.Analysis the thermal properties and particle size of the prepared glass frits through DTA analyzer and laser mastersizer.Through sessile drop to research the wetting property between the prepared glass frits and alumina substrate in high temperature,and observe the cross-sections of the sintered samples through scanning electron microscope(SEM) to study their adhesion strength.
Preparation and Properties of Sintering Brick from Iron Tailings
Authors: Zuo Ran Fang , Du Gao Xiang , Mei Le Fu , Guo Wei Juan , Liao Jing Hui
Published: June 2012

The main objective of this paper was to investigate the addition of iron tailing sintering brick production, in the presence of clay, coal refuses and bentonite. Mixtures containing raw materials of sintering brick and iron tailings were prepared at different proportions (up to 55 wt %), fired at 980°C. Freeze/thaw durability, drying and firing shrinkages were investigated as well as the loss on ignition, bulk density and compressive strength of the fired samples. Their mechanical and microstructure properties were also investigated by differential thermal analysis (DTA/TG), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that compressive strengths of the brick samples are higher than that required by the standards MU15 of GB5101-2003, up to 21.79Mpa with 40% iron tailings corresponding to its higher bulk density completely. Moreover, the results showed that it has such advantages as no lime blowing, uniform color, good freeze/thaw resistance and slight universal frost.
Kinetic Analysis of Sulfation of Fe-Ca Based Sorbent for FGD
Authors: Zhao Rong Fang , Shen You Liang , Ruan Cheng Xiang , Gao Wei Min
Published: June 2012

Sulfation performance of a Fe-Ca based sorbent prepared from iron oxide-rich metallurgical dust and lime is investigated using thermogravimetric analysis (TGA) in the temperature range of 300-550°C, and the kinetics of the sulfation reaction is analyzed using the grain model. Comparison between the model simulation results and experimental data demonstrates that the grain model can give a relatively satisfactory description of the experimental results. In detail, the overall rate of the sulfation reaction is mainly controlled by diffusion, despite by chemical kinetics at a very low degree of conversion (lower than 0.056), and that the higher diffusion activation energy (E D, 25460J/mol) and smaller diffusion frequency factor (D e0,4.42×10–2 cm2/min), in relative to those of the sulfation reaction (13008J/mol for E a and 1.65 cm/min for k s0), may account for the shift in control mechanism, the role of diffusion in the sorbent conversion, and consequently the flat-convex conversion vs. time curves obtained by TGA.
Electrical Properties and Microstructures of Tb4O7-Doped Bi4Ti3O12 Ceramics
Authors: Mei X.A. , Chen M. , Liu R.F. , Huang Chong Qing , Liu J.
Published: June 2012

The electrical properties of Tb4O7-bismuth titanate (Bi3.3Tb0.6Ti3O12) prepared by a conventional ceramic technique have been investigated. At applied d.c. field below 200V/mm, the current-voltage curve of Tb-doped sample exhibits a simple ohmic behavior. The impedance spectrum of Tb-doped sample indicates that consist of semiconducting grain and moderately insulating grain boundary regions. XRD, SEM and EPMA analyses reveal crystalline phase characterized by a Bi-layered perovskite structure of Bi4Ti3O12 and the distribution of every element is uniform. Tb-doped sample exhibit randomly oriented and plate-like morphology.
Preparation and Mechanical Energy Harvesting of BaTi0.9Zr0.1O3 Ceramic Nanofibers
Authors: Xiao Xiao Peng , Hu Peng , Xiong Zhao Xian , Xue Hao , Lu Qing Jun , Ye He Lan , Zhang Guo Feng
Published: June 2012

Piezoelectric barium zirconate-titanate ceramic nanofibers were prepared by combination of Sol-Gel processing and electrospinning technique. The average diameter of barium zirconate-titanate ceramic nanofibers is nearly 200 nm. The x-ray diffraction pattern of the fibers showed that their crystalline structures displayed tetragonal perovskite structures. Interdigitated electrodes were sprayed on an epoxy resin substrate. BaTi0.9Zr0.1O3 nanofibers were then aligned on the interdigitated electrodes and covered with the solution of epoxy resin, so as to obtain Piezoelectric Fiber/polymer Composites. The periodic output voltages with maximum value of 0.26V were obtained under harmonic excitation, by using a finger to apply a dynamic load on the top of the composites.
The Preparation of ZnO Nanopowders and Dye Sensitized Solar Cells By Sol-Gel Method
Authors: Wang Yan Xiang , Jian Sun , Zhao Bing Xin
Published: June 2012

In this paper, ZnO nanopowders and dye sensitized solar cells were prepared by sol-gel and screen printing method, respectively. First, ZnO nanopowders were synthesized by using zinc acetate, ethanol and diethanolamined as raw materials. The effects of Zn2+ molar concentration on the microstructure and photocatalytic efficiency of ZnO nanopowders were investigated. When Zn2+molar concentration were 0.4M, 0.6M, 0.8M and 1.2M, ZnO nanoparticles with diameter of about 80~100nm were obtained. When Zn2+ molar concentration reached 2.4M, ZnO nanobowls consisted of nanoparticles with diameter about 80~100nm were synthesized. When Zn2+molar concentration reached 3.6M, ZnO nanoparticles were obtained, and particle size distribution of obtained ZnO nanoparticles became broader. Methyl orange degradation rate of ZnO nanopowders prepared with 0.4M, after treated by ultraviolet radiation for 8 hours, were up to 88.5%. ZnO nanopowders prepared with 1.2M and 3.6M were assembled into solar cells. The properties of the solar cell prepared with 1.2M were optimal. The short-circuit photocurrent, open-circuit photovoltage, fill factor and efficiency were 14.72 mA/cm2, 0.649V, 0.332 and 0.914%, respectively.
Preparation and Characterization of High Purity β-SiC Powder
Authors: Jung Eun Jin , Lee Yoon Joo , Kim Soo Ryong , Kwon Woo Teck , Choi Se Young , Kim Young Hee
Published: June 2012

SiC powder can be produced generally through the Acheson process and it is required long carbothermic reaction time of SiO2 with carbon powder around 2200 °C ~ 2400 °C. Due to the high reaction temperature and long reaction time of the process, the powders produced have a large particle size and consist of mostly alpha phase SiC. Synthetic temperature of beta phase SiC powder is known to produce at 1700 °C ~ 1900 °C which is lower temperature than that of alpha phase SiC powder. We prepared β-SiC powder by heating precursor derived from the mixture of phenolic resin and tetraethyl orthosilicate. The precursor was heated at 1800 °C for 4 h in an Ar atmosphere. In order to examine the pyrolysis residue after the heat treatment, the SiC powder was analyzed with XRD and SEM. The X-ray diffraction result of the SiC powder shows the diffraction peaks around 35°, 60°, and 73° corresponded to the beta SiC phase. β-SiC powder prepared in this study contains lower metallic impurities compare than that of α-SiC powder prepared from Acheson method and is able to use as a good starting material for SiC single crystal growing.
The Preparation and Assessment of the Rigid Aerogel Insulation Composites
Authors: Liu Rui Xiang , Cui Tang Yin , Zhou Chang Ling , Wang Chong Hai , Wang Yan Yan , Sui Xue Ye
Published: June 2012

The hydrophobic aerogel heating-insulating composite ceramic was fabricated in the way of constant pressure. The properties of the ceramic were attributed through FT-IR and energy spectrum. The microstructure and phase transformation of the insulation composites ceramic was characterized by scanning electron microscopy. The results show that after compositing with aerogel the coefficient of heat conductivity of the heat-insulating ceramic decreases forty-sixty percent and the compressive strength increases a hundred percent. There is little change to the tensile-strength. The holes of the ceramic are full of aero gel particles whose grain size is ten-twenty μm and the distribution of pore size is ten-seventy nm. After heating at 400°C for 12 minutes by quartz lamp on the surface of the ceramic which the thick of it is 8mm, the temperature of the other side increases 10°C .When the thick of the ceramic is 16mm, the temperature of the other side remains unchanged. The ceramic has excellent heating-insulting property.
One-Pot Synthesis of Composite Nano-Capsules with Paraffin as Core and PMMA-SiO2 as Shell by Interfacial Hydrolysis and Polymerization
Authors: Wu Xiao Lin , Sun Rong , Zhu Peng Li , Du Ru Xu
Published: June 2012

Nano-capsules with organic-inorganic composite PMMA-SiO2 as the shell and paraffin as the core have been largely and rapidly synthesized by the cooperative reaction of interfacial hydrolysis and polymerization. Ammonium persulfate as the initiator and catalyst was used to make the polymerization and hydrolysis process occurring simultaneously and to improve the uniformity and controllability of capsule morphology. The prepared homogeneous core-shell structures of capsules with the grain size around 100 nm have small volume change and stable thermodynamic characteristics. The cooperative reactions of polymerization and hydrolysis process provide a convenient and efficient method for preparing homogeneous and stable organic-inorganic composite capsules.
Design of Database for High Speed Cutting of Difficult-to-Cut Materials
Authors: Liu Li Juan , Wu Wen Ge , Lv Ming
Published: June 2012

High speed machining (HSM) is one of the main trends of cutting machinery and is an important development direction of advanced manufacturing technology. In our country, the relevant research of HSM database starts later, especially of the cutting of hardworking material, the actual machining and experiment on the machining technology and the machining parameters of HSM are few, the reasonable machining parameters selection scheme and the appropriate cutter choice method are lack. The paper established HSM database system of the hardworking material based on web to improve cutting efficiency. According to the different feed and cutting tool by the Web form, it gets the rational cutting parameters. And the system determines the tool-path planning by the manufacture HSM of hardworking material processing animation to simulate the high-speed milling. The results of inquiry as a Web page and let you get parameters of optimization, increases efficiency of factories.
Myeloid Dendritic Cells from B6.NZM Sle1/Sle2/Sle3 Lupus-Prone Mice Express an IFN Signature That Precedes Disease Onset
Authors: Sriram Uma , Varghese Linda , Bennett Heather L. , Jog Neelakshi R. , Shivers Debra K. , Ning Yue , Behrens Edward M. , Caricchio Roberto , Gallucci Stefania
Published: June 2012

Patients with systemic lupus erythematosus show an overexpression of type I IFN-responsive genes that is referred to as “IFN signature.” We found that B6.NZMSle1/Sle2/Sle3 (Sle1,2,3) lupus-prone mice also express an IFN signature compared with non-autoimmune C57BL/6 mice. In vitro, myeloid dendritic cells (mDCs) (GM-CSF bone marrow-derived dendritic cells; BMDCs) from Sle1,2,3 mice constitutively overexpressed IFN-responsive genes such as IFN-β, Oas-3, Mx-1, ISG-15, and CXCL10 and members of the IFN signaling pathway STAT1, STAT2, and IRF7. The IFN signature was similar in Sle1,2,3 BMDCs from young, pre-autoimmune mice and from mice with high titers of autoantibodies, suggesting that the IFN signature in mDCs precedes disease onset and is independent from the autoantibodies. Sle1,2,3 BMDCs hyperresponded to stimulation with IFN-α and the TLR7 and TLR9 agonists R848 and CpGs. We propose that this hyperresponse is induced by the IFN signature and only partially contributes to the signature, as oligonucleotides inhibitory for TLR7 and TLR9 only partially suppressed the constitutive IFN signature, and pre-exposure to IFN-α induced the same hyperresponse in wild-type BMDCs as in Sle1,2,3 BMDCs. In vivo, mDCs and to a lesser extent T and B cells from young prediseased Sle1,2,3 mice also expressed the IFN signature, although they lacked the strength that BMDCs showed in vitro. Sle1,2,3 plasmacytoid DCs expressed the IFN signature in vitro but not in vivo, suggesting that mDCs may be more relevant before disease onset. We propose that Sle1,2,3 mice are useful tools to study the role of the IFN signature in lupus pathogenesis.
Comprehensive Analysis of CD4+ T Cells in the Decision between Tolerance and Immunity In Vivo Reveals a Pivotal Role for ICOS
Authors: Lischke Timo , Hegemann Anika , Gurka Stephanie , Vu Van Dana , Burmeister Yvonne , Lam Kong-Peng , Kershaw Olivia , Mollenkopf Hans-Joachim , Mages Hans Werner , Hutloff Andreas , Kroczek Richard A.
Published: June 2012

We have established a comprehensive in vivo mouse model for the CD4+ T cell response to an “innocuous” versus “dangerous” exogenous Ag and developed an in vivo test for tolerance. In this model, specific gene-expression signatures, distinctive upregulation of early T cell-communication molecules, and differential expansion of effector T cells (Teff) and regulatory T cells (Treg) were identified as central correlates of T cell tolerance and T cell immunity. Different from essentially all other T cell-activation molecules, ICOS was found to be induced in the immunity response and not by T cells activated under tolerogenic conditions. If expressed, ICOS did not act as a general T cell costimulator but selectively caused a massive expansion of effector CD4+ T cells, leaving the regulatory CD4+ T cell compartment largely undisturbed. Thus, ICOS strongly contributed to the dramatic change in the balance between Ag-specific Teff and Treg from ∼1:1 at steady state to 21:1 at the height of the immune response. This newly defined role for the balance of Teff to Treg, together with its known key function in T cell help for B cells, establishes ICOS as a central mediator of immunity. Given its exceptionally selective induction on CD4+ T cells under inflammatory, but not tolerogenic, conditions, ICOS emerges as a pivotal effector molecule in the early decision between tolerance and immunity to exogenous Ag.
B7-H1, Which Represses EBV-Immortalized B Cell Killing by Autologous T and NK Cells, Is Oppositely Regulated by c-Myc and EBV Latency III Program at Both mRNA and Secretory Lysosome Levels
Authors: Durand-Panteix Stéphanie , Farhat Mona , Youlyouz-Marfak Ibtissam , Rouaud Pauline , Ouk-Martin Catherine , David Amandine , Faumont Nathalie , Feuillard Jean , Jayat-Vignoles Chantal
Published: June 2012

EBV-immortalized B cells induce a complex immune response such that the virus persists as a clinically silent infection for the lifetime of the infected host. B7-H1, also called PD-L1, is a cosignaling molecule of the B7 family that can inhibit activated T cell effectors by interaction with its receptor PD-1. In this work, we have studied the dependence of B7-H1 on NF-κB and c-Myc, the two main transcription factors in EBV latency III proliferating B cells, on various lymphoblastoid and Burkitt lymphoma cell lines, some of them being inducible or not for the EBV latency III program and/or for c-Myc. We found that B7-H1 repressed killing of EBV-immortalized B cells by their autologous T and NK cells. At the mRNA level, NF-κB was a weak inducer whereas c-Myc was a strong repressor of B7-H1 expression, an effect mediated by STAT1 inhibition. At the protein level, B7-H1 molecules were stored in both degradative and unconventional secretory lysosomes. Surface membrane B7-H1 molecules were constitutively internalized and proteolyzed in lysosomes. The EBV latency III program increased the amounts of B7-H1–containing secretory lysosomes and their export to the surface membrane. By repressing actin polymerization, c-Myc blocked secretory lysosome migration and B7-H1 surface membrane export. In addition to B7-H1, various immunoregulatory molecules participating in the immunological synapse are stored in secretory lysosomes. By playing on actin polymerization, c-Myc could thus globally regulate the immunogenicity of transformed B cells, acting on export of secretory lysosomes to plasma membrane.
Cutting Edge: MicroRNA Regulation of Macrophage Fusion into Multinucleated Giant Cells
Authors: Sissons James R. , Peschon Jacques J. , Schmitz Frank , Suen Rosa , Gilchrist Mark , Aderem Alan
Published: June 2012

Cellular fusion of macrophages into multinucleated giant cells is a distinguishing feature of the granulomatous response to inflammation, infection, and foreign bodies (Kawai and Akira. 2011. Immunity 34: 637–650). We observed a marked increase in fusion of macrophages genetically deficient in Dicer, an enzyme required for canonical microRNA (miRNA) biogenesis. Gene expression profiling of miRNA-deficient macrophages revealed an upregulation of the IL-4–responsive fusion protein Tm7sf4, and analyses identified miR-7a-1 as a negative regulator of macrophage fusion, functioning by directly targeting Tm7sf4 mRNA. miR-7a-1 is itself an IL-4–responsive gene in macrophages, suggesting feedback control of cellular fusion. Collectively, these data indicate that miR-7a-1 functions to regulate IL-4–directed multinucleated giant cell formation.
Retinoid X Receptor Agonists Impair Arterial Mononuclear Cell Recruitment through Peroxisome Proliferator-Activated Receptor-γ Activation
Authors: Sanz Maria-Jesus , Albertos Fernando , Otero Eduardo , Juez Marina , Morcillo Esteban J. , Piqueras Laura
Published: June 2012

Mononuclear cell migration into the vascular subendothelium constitutes an early event of the atherogenic process. Because the effect of retinoid X receptor (RXR)α on arterial mononuclear leukocyte recruitment is poorly understood, this study investigated whether RXR agonists can affect this response and the underlying mechanisms involved. Decreased RXRα expression was detected after 4 h stimulation of human umbilical arterial endothelial cells with TNF-α. Interestingly, under physiological flow conditions, TNF-α–induced endothelial adhesion of human mononuclear cells was concentration-dependently inhibited by preincubation of the human umbilical arterial endothelial cells with RXR agonists such as bexarotene or 9-cis-retinoid acid. RXR agonists also prevented TNF-α–induced VCAM-1 and ICAM-1 expression, as well as endothelial growth-related oncogene-α and MCP-1 release. Suppression of RXRα expression with a small interfering RNA abrogated these responses. Furthermore, inhibition of MAPKs and NF-κB pathways were involved in these events. RXR agonist-induced antileukocyte adhesive effects seemed to be mediated via RXRα/peroxisome proliferator-activated receptor (PPAR)γ interaction, since endothelial PPARγ silencing abolished their inhibitory responses. Furthermore, RXR agonists increased RXR/PPARγ interaction, and combinations of suboptimal concentrations of both nuclear receptor ligands inhibited TNF-α–induced mononuclear leukocyte arrest by 60–65%. In vivo, bexarotene dose-dependently inhibited TNF-α–induced leukocyte adhesion to the murine cremasteric arterioles and decreased VCAM-1 and ICAM-1 expression. Therefore, these results reveal that RXR agonists can inhibit the initial inflammatory response that precedes the atherogenic process by targeting different steps of the mononuclear recruitment cascade. Thus, RXR agonists may constitute a new therapeutic tool in the control of the inflammatory process associated with cardiovascular disease.
TLR5, a Novel and Unidentified Inflammatory Mediator in Rheumatoid Arthritis that Correlates with Disease Activity Score and Joint TNF-α Levels
Authors: Chamberlain Nathan D. , Vila Olga M. , Volin Michael V. , Volkov Suncica , Pope Richard M. , Swedler William , Mandelin Arthur M. , Shahrara Shiva
Published: June 2012

The innate immune system plays an important role in rheumatoid arthritis (RA) pathogenesis. Previous studies support the role of TLR2 and 4 in RA and experimental arthritis models; however, the regulation and pathogenic effect of TLR5 is undefined in RA. In this study, we show that TLR5 is elevated in RA and osteoarthritis ST lining and sublining macrophages and endothelial cells compared with normal individuals. Furthermore, expression of TLR5 is elevated in RA synovial fluid macrophages and RA peripheral blood monocytes compared with RA and normal peripheral blood in vitro-differentiated macrophages. We also found that TLR5 on RA monocytes is an important modulator of TNF-α in RA synovial fluid and that TLR5 expression on these cells strongly correlates with RA disease activity and TNF-α levels. Interestingly, TNF-α has a feedback regulation with TLR5 expression in RA monocytes, whereas expression of this receptor is regulated by IL-17 and IL-8 in RA macrophages and fibroblasts. We show that RA monocytes and macrophages are more responsive to TLR5 ligation compared with fibroblasts despite the proinflammatory response being mediated through the same signaling pathways in macrophages and fibroblasts. In conclusion, we document the potential role of TLR5 ligation in modulating transcription of TNF-α from RA synovial fluid and the strong correlation of TLR5 and TNF-α with each other and with disease activity score in RA monocytes. Our results suggest that expression of TLR5 may be a predictor for RA disease progression and that targeting TLR5 may suppress RA.
TLR Signaling Prevents Hyperoxia-Induced Lung Injury by Protecting the Alveolar Epithelium from Oxidant-Mediated Death
Authors: Ballinger Megan N. , Newstead Michael W. , Zeng Xianying , Bhan Urvashi , Horowitz Jeffrey C. , Moore Bethany B. , Pinsky David J. , Flavell Richard A. , Standiford Theodore J.
Published: June 2012

Mechanical ventilation using high oxygen tensions is often necessary to treat patients with respiratory failure. Recently, TLRs were identified as regulators of noninfectious oxidative lung injury. IRAK-M is an inhibitor of MyD88-dependent TLR signaling. Exposure of mice deficient in IRAK-M (IRAK-M−/−) to 95% oxygen resulted in reduced mortality compared with wild-type mice and occurred in association with decreased alveolar permeability and cell death. Using a bone marrow chimera model, we determined that IRAK-M’s effects were mediated by structural cells rather than bone marrow-derived cells. We confirmed the expression of IRAK-M in alveolar epithelial cells (AECs) and showed that hyperoxia can induce the expression of this protein. In addition, IRAK-M−/− AECs exposed to hyperoxia experienced a decrease in cell death. IRAK-M may potentiate hyperoxic injury by suppression of key antioxidant pathways, because lungs and AECs isolated from IRAK-M−/− mice have increased expression/activity of heme oxygenase-1, a phase II antioxidant, and NF (erythroid-derived)-related factor-2, a transcription factor that initiates antioxidant generation. Treatment of IRAK-M−/− mice in vivo and IRAK-M−/− AECs in vitro with the heme oxygenase-1 inhibitor, tin protoporphyrin, substantially decreased survival and significantly reduced the number of live cells after hyperoxia exposure. Collectively, our data suggest that IRAK-M inhibits the induction of antioxidants essential for protecting the lungs against cell death, resulting in enhanced susceptibility to hyperoxic lung injury.
Hepatitis B Virus-Induced Calreticulin Protein Is Involved in IFN Resistance
Authors: Yue Xin , Wang Hui , Zhao Fanpeng , Liu Shi , Wu Jianguo , Ren Wendan , Zhu Ying
Published: June 2012

IFN-α is a widely used treatment for hepatitis B virus (HBV) infection, and IFN resistance caused by viral and/or host factors is currently a challenging clinical problem. A better understanding of the molecular mechanisms underlying IFN immunotherapy in the treatment of viral infection would be very beneficial clinically and is of immense clinical importance. Calreticulin (CRT) is an endoplasmic reticulum luminal calcium-binding chaperone that is involved in the regulation of calcium homoeostasis, the folding of newly synthesized proteins, and many other cellular functions. However, little is known about the role of CRT in HBV infection. In this study, we observed high levels of CRT expression in the sera and PBMCs of patients with HBV relative to those of healthy individuals. HBV upregulated the expression of CRT at the transcriptional level. Further investigation showed that HBV-induced CRT enhanced HBV replication by antagonizing the IFN pathway. CRT suppressed the production of endogenous IFN-α by reducing the nuclear translocation of IFN regulatory factor-7 but not IFN regulatory factor-3. Furthermore, CRT also suppressed the antiviral activity of IFN-α by inhibiting the phosphorylation of STAT1 and decreasing the expression of two IFN-α downstream effectors, protein kinase R and 2',5′-oligoadenylate synthetase. Our results offer new insights into the pathogenesis of HBV infection and may provide potential targets for anti-HBV therapy.
Zinc Supplementation during Pregnancy Protects against Lipopolysaccharide-Induced Fetal Growth Restriction and Demise through Its Anti-inflammatory Effect
Authors: Chen Yuan-Hua , Zhao Mei , Chen Xue , Zhang Ying , Wang Hua , Huang Ying-Ying , Wang Zhen , Zhang Zhi-Hui , Zhang Cheng , Xu De-Xiang
Published: June 2012

LPS is associated with adverse developmental outcomes, including preterm delivery, fetal death, teratogenicity, and intrauterine growth restriction (IUGR). Previous reports showed that zinc protected against LPS-induced teratogenicity. In the current study, we investigated the effects of zinc supplementation during pregnancy on LPS-induced preterm delivery, fetal death and IUGR. All pregnant mice except controls were i.p. injected with LPS (75 μg/kg) daily from gestational day (GD) 15 to GD17. Some pregnant mice were administered zinc sulfate through drinking water (75 mg elemental Zn per liter) throughout the pregnancy. As expected, an i.p. injection with LPS daily from GD15 to GD17 resulted in 36.4% (4/11) of dams delivered before GD18. In dams that completed the pregnancy, 63.2% of fetuses were dead. Moreover, LPS significantly reduced fetal weight and crown–rump length. Of interest, zinc supplementation during pregnancy protected mice from LPS-induced preterm delivery and fetal death. In addition, zinc supplementation significantly alleviated LPS-induced IUGR and skeletal development retardation. Further experiments showed that zinc supplementation significantly attenuated LPS-induced expression of placental inflammatory cytokines and cyclooxygenase-2. Zinc supplementation also significantly attenuated LPS-induced activation of NF-κB and MAPK signaling in mononuclear sinusoidal trophoblast giant cells of the labyrinth zone. It inhibited LPS-induced placental AKT phosphorylation as well. In conclusion, zinc supplementation during pregnancy protects against LPS-induced fetal growth restriction and demise through its anti-inflammatory effect.
B7-H3 Participates in the Development of Experimental Pneumococcal Meningitis by Augmentation of the Inflammatory Response via a TLR2-Dependent Mechanism
Authors: Chen Xuqin , Quinn Edel M. , Ni Hong , Wang Jian , Blankson Siobhan , Redmond H. Paul , Wang Jiang Huai , Feng Xing
Published: June 2012

In addition to a well-documented role in regulating T cell-mediated immune responses, B7-H3, a newly discovered member of the B7 superfamily, has been recently identified as a costimulator in the innate immunity-mediated inflammatory response. In this study, we further report that B7-H3 participates in the development of pneumococcal meningitis in a murine model. Exogenous administration of B7-H3 strongly amplified the inflammatory response, exacerbated blood–brain barrier disruption, and aggravated the clinical disease status in Streptococcus pneumoniae-infected C3H/HeN wild-type mice. Consistent with the in vivo findings, B7-H3 substantially augmented proinflammatory cytokine and chemokine production, upregulated NF-κB p65 and MAPK p38 phosphorylation, and enhanced the nuclear transactivation of NF-κB p65 at both TNF-α and IL-6 promoters in S. pneumoniae-stimulated primary murine microglia cells. These B7-H3–associated in vitro and in vivo effects appeared to be dependent on TLR2 signaling, as B7-H3 almost completely lost its amplifying actions in both TLR2-deficient microglial cells and TLR2-deficient mice. Furthermore, administration of the anti–B7-H3 mAb (MIH35) attenuated the inflammatory response and ameliorated blood–brain barrier disruption in S. pneumoniae-infected wild-type mice. Collectively, our results indicate that B7-H3 plays a contributory role in the development of S. pneumoniae infection-induced bacterial meningitis.
Vasoactive Intestinal Peptide Downregulates Proinflammatory TLRs While Upregulating Anti-Inflammatory TLRs in the Infected Cornea
Authors: Jiang Xiaoyu , McClellan Sharon A. , Barrett Ronald P. , Zhang Yunfan , Hazlett Linda D.
Published: June 2012

TLRs recognize microbial pathogens and trigger an immune response, but their regulation by neuropeptides, such as vasoactive intestinal peptide (VIP), during Pseudomonas aeruginosa corneal infection remains unexplored. Therefore, C57BL/6 (B6) mice were injected i.p. with VIP, and mRNA, protein, and immunostaining assays were performed. After VIP treatment, PCR array and real-time RT-PCR demonstrated that proinflammatory TLRs (conserved helix-loop-helix ubiquitous kinase, IRAK1, TLR1, TLR4, TLR6, TLR8, TLR9, and TNFR-associated factor 6) were downregulated, whereas anti-inflammatory TLRs (single Ig IL-1–related receptor [SIGIRR] and ST2) were upregulated. ELISA showed that VIP modestly downregulated phosphorylated inhibitor of NF-κB kinase subunit α but upregulated ST2 ~2-fold. SIGIRR was also upregulated, whereas TLR4 immunostaining was reduced in cornea; all confirmed the mRNA data. To determine whether VIP effects were cAMP dependent, mice were injected with small interfering RNA for type 7 adenylate cyclase (AC7), with or without VIP treatment. After silencing AC7, changes in mRNA levels of TLR1, TNFR-associated factor 6, and ST2 were seen and unchanged with addition of VIP, indicating that their regulation was cAMP dependent. In contrast, changes were seen in mRNA levels of conserved helix-loop-helix ubiquitous kinase, IRAK1, 2, TLR4, 9 and SIGIRR following AC7 silencing alone; these were modified by VIP addition, indicating their cAMP independence. In vitro studies assessed the effects of VIP on TLR regulation in macrophages and Langerhans cells. VIP downregulated mRNA expression of proinflammatory TLRs while upregulating anti-inflammatory TLRs in both cell types. Collectively, the data provide evidence that VIP downregulates proinflammatory TLRs and upregulates anti-inflammatory TLRs and that this regulation is both cAMP dependent and independent and involves immune cell types found in the infected cornea.
Neutrophil Cerebrovascular Transmigration Triggers Rapid Neurotoxicity through Release of Proteases Associated with Decondensed DNA
Authors: Allen Charlotte , Thornton Peter , Denes Adam , McColl Barry W. , Pierozynski Adam , Monestier Marc , Pinteaux Emmanuel , Rothwell Nancy J. , Allan Stuart M.
Published: June 2012

Cerebrovascular inflammation contributes to diverse CNS disorders through mechanisms that are incompletely understood. The recruitment of neutrophils to the brain can contribute to neurotoxicity, particularly during acute brain injuries, such as cerebral ischemia, trauma, and seizures. However, the regulatory and effector mechanisms that underlie neutrophil-mediated neurotoxicity are poorly understood. In this study, we show that mouse neutrophils are not inherently toxic to neurons but that transendothelial migration across IL-1–stimulated brain endothelium triggers neutrophils to acquire a neurotoxic phenotype that causes the rapid death of cultured neurons. Neurotoxicity was induced by the addition of transmigrated neutrophils or conditioned medium, taken from transmigrated neutrophils, to neurons and was partially mediated by excitotoxic mechanisms and soluble proteins. Transmigrated neutrophils also released decondensed DNA associated with proteases, which are known as neutrophil extracellular traps. The blockade of histone–DNA complexes attenuated transmigrated neutrophil-induced neuronal death, whereas the inhibition of key neutrophil proteases in the presence of transmigrated neutrophils rescued neuronal viability. We also show that neutrophil recruitment in the brain is IL-1 dependent, and release of proteases and decondensed DNA from recruited neutrophils in the brain occurs in several in vivo experimental models of neuroinflammation. These data reveal new regulatory and effector mechanisms of neutrophil-mediated neurotoxicity (i.e., the release of proteases and decondensed DNA triggered by phenotypic transformation during cerebrovascular transmigration). Such mechanisms have important implications for neuroinflammatory disorders, notably in the development of antileukocyte therapies.
A Note on the Estimation of Long-Run Relationships in Panel Equations with Cross-Section Linkages
Authors: Di Iorio Francesca , Fachin Stefano
Published: June 2012

The authors address the issue of estimation and inference in dependent nonstationary panels of small cross-section dimensions. The main conclusion is that the best results are obtained applying bootstrap inference to single-equation estimators, such as fully modified ordinary least squares and dynamic ordinary least squares. Seemingly unrelated regression estimators perform badly, or are even unfeasible, when the time dimension is not very large compared to the cross-section dimension.
Iodine monoxide in the north subtropical free troposphere
Authors: Puentedura O. , Gil M. , Saiz-Lopez A. , Hay T. , Navarro-Comas M. , Gómez-Pelaez A. , Cuevas E. , Iglesias J. , Gomez L.
Published: June 2012

Abstract. Iodine monoxide (IO) differential slant column densities (DSCD) have been retrieved from a new multi-axis differential optical absorption spectroscopy (MAX-DOAS) instrument deployed at the Izaña subtropical observatory as part of the Network for the Detection of Atmospheric Composition Change (NDACC) programme. The station is located at 2370 m a.s.l., well above the trade wind inversion that limits the top of the marine boundary layer, and hence is representative of the free troposphere. We report daily observations from May to August 2010 at different viewing angles. During this period, the spectral signature of IO was unequivocally detected on every day of measurement. A mean IO DSCD of 1.52×1013 molecules cm−2 was observed at the 5° instrument elevation angle (IEA) on clear days using a single zenith reference for the reported period, with a day-to-day variability of 33% at one standard deviation. Based on the simulation of the DSCDs using radiative transfer calculations with five different hypothesized IO profiles, the IO mixing ratio is estimated to range between 0.2 and 0.4 pptv in the free troposphere. Episodes of Saharan dust outbreaks were also observed, with large increases in the DSCDs at higher IEA, suggesting an enhancement of IO inside the dust cloud.