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Leukocyte-specific protein 1 regulates T-cell migration in rheumatoid arthritis
Copy number variations (CNVs) have been implicated in human diseases. However, it remains unclear how they affect immune dysfunction and autoimmune diseases, including rheumatoid arthritis (RA). Here, we identified a novel leukocyte-specific protein 1 (LSP1) deletion variant for RA susceptibility located in 11p15.5. We replicated that the copy number of LSP1 gene is significantly lower in patients with RA, which correlates positively with LSP1 protein expression levels. Differentially expressed genes in Lsp1-deficient primary T cells represent cell motility and immune and cytokine responses. Functional assays demonstrated that LSP1, induced by T-cell receptor activation, negatively regulates T-cell migration by reducing ERK activation in vitro. In mice with T-cell-dependent chronic inflammation, loss of Lsp1 promotes migration of T cells into the target tissues as well as draining lymph nodes, exacerbating disease severity. Moreover, patients with RA show diminished expression of LSP1 in peripheral T cells with increased migratory capacity, suggesting that the defect in LSP1 signaling lowers the threshold for T-cell activation. To our knowledge, our work is the first to demonstrate how CNVs result in immune dysfunction and a disease phenotype. Particularly, our data highlight the importance of LSP1 CNVs and LSP1 insufficiency in the pathogenesis of RA and provide previously unidentified insights into the mechanisms underlying T-cell migration toward the inflamed synovium in RA.
Hierarchical Nanostructured Pt8Ti-TiO2/C as an Efficient and Durable Anode Catalyst for Direct Methanol Fuel Cells
A catalyst for the electrochemical oxidation of methanol in direct methanol fuel cells (DMFCs) comprising Pt8Ti intermetallic nanoparticles dispersed in carbon nanorods (Pt8Ti-TiO2/C) is presented. The catalyst consists of Pt8Ti and rutile TiO2 nanoparticles dispersed in nitrogen-doped carbon hierarchical nanostructures. The Pt8Ti-TiO2/C catalyst showed a 50 mV positive onset potential and 10 times higher specific activity than a commercial Pt/C catalyst. Using a half-cell experiment, we show that Pt8Ti intermetallic nanoparticles greatly enhance the methanol oxidation activity and durability in comparison to a Pt/C commercial catalyst. More importantly, a DMFC anode constructed with Pt8Ti-TiO2/C catalyst showed 4.6 times higher power density than a commercial Pt/C catalyst at 0.35 V and 333 K. Additionally, the Pt8Ti-TiO2/C catalyst displayed superior durability in comparison to the Pt/C catalyst. Pt8Ti-TiO2/C showed an electrochemical surface area decay of 23% at the end of 3000 CV cycles, whereas the Pt/C catalyst showed a more rapid decay of 90% at the end of 3000 CV cycles. The excellent stability of the Pt8Ti-TiO2/C catalyst during the accelerated durability stability test (AST) can be attributed to the stability of the rutile TiO2 support, which is chemically resistant in the acidic electrolyte medium. The chronoamperometry and AST durability results confirmed that the Pt8Ti-TiO2/C hierarchical catalyst exhibited better stability than the pure Pt/C catalyst, suggesting that Pt8Ti-TiO2/C could be a promising anode catalyst in DMFCs. © 2015 American Chemical Society.
Ferromagnetic, Folded Electrode Composite as a Soft Interface to the Skin for Long-Term Electrophysiological Recording
A class of ferromagnetic, folded, soft composite material for skin-interfaced electrodes with releasable interfaces to stretchable, wireless electronic measurement systems is introduced. These electrodes establish intimate, adhesive contacts to the skin, in dimensionally stable formats compatible with multiple days of continuous operation, with several key advantages over conventional hydrogel-based alternatives. The reported studies focus on aspects ranging from ferromagnetic and mechanical behavior of the materials systems, to electrical properties associated with their skin interface, to system-level integration for advanced electrophysiological monitoring applications. The work combines experimental measurement and theoretical modeling to establish the key design considerations. These concepts have potential uses across a diverse set of skin-integrated electronic technologies. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Facile one-pot chemical approach for synthesis of monodisperse chain-like superparamagnetic maghemite (gamma-Fe2O3) nanoparticles
In this study, we demonstrated a novel and facile chemical approach for synthesis of monodisperse maghemite (γ-Fe<inf>2</inf>O<inf>3</inf>) nanoparticles. Compared to the reported works for synthesis of maghemite nanoparticles which require the use of much amount of surfactant and complicated procedures, we could develop here an approach in which we did not use any surfactant or deoxygenated condition and further the synthesis process was also completed in a single reaction. X-ray diffraction analysis of the sample confirms single phase fully crystalline spinel structure. Transmission electron microscopy images reveal that the shape of the synthesized maghemite nanoparticles is a mix of spherical and cube with chain-like patterns and the average particles size is of 25nm. The obtained maghemite (γ-Fe<inf>2</inf>O<inf>3</inf>) nanoparticles showed high magnetic moment of 65emu/g with superparamagnetic properties. Owing to the high moment, mono disperse superparamagnetic nature of the sample, the synthesized maghemite nanoparticles are useful for biomedical applications. © 2015 The Korean Society of Industrial and Engineering Chemistry.
Dynamic trajectory analysis of superparamagnetic beads driven by on-chip micromagnets
We investigate the non-linear dynamics of superparamagnetic beads moving around the periphery of patterned magnetic disks in the presence of an in-plane rotating magnetic field. Three different dynamical regimes are observed in experiments, including (1) phase-locked motion at low driving frequencies, (2) phase-slipping motion above the first critical frequency fc1, and (3) phase-insulated motion above the second critical frequency fc2. Experiments with Janus particles were used to confirm that the beads move by sliding rather than rolling. The rest of the experiments were conducted on spherical, isotropic magnetic beads, in which automated particle position tracking algorithms were used to analyze the bead dynamics. Experimental results in the phase-locked and phase-slipping regimes correlate well with numerical simulations. Additional assumptions are required to predict the onset of the phase-insulated regime, in which the beads are trapped in closed orbits; however, the origin of the phase-insulated state appears to result from local magnetization defects. These results indicate that these three dynamical states are universal properties of bead motion in non-uniform oscillators. © 2015 AIP Publishing LLC.
Physiochemical properties of combustion synthesized La0.6Sr0.4Co0.8Fe0.2O3-delta perovskite: A role of fuel to oxidant ratio
Abstract The solution combustion synthesis is a novel approach to synthesize the nanocrystalline materials with an unexpectedly high surface to volume ratio. Thus, in present paper, La0.6Sr0.4Co0.8Fe0.2O3-δ powders have been synthesized by solution combustion synthesis route at different fuel to oxidant ratio (ψ) and its effect on different physiochemical properties have been studied. The mode of propagation of combustion reaction changed from smoldering to volume with increasing ψ. The thermal analysis shows that exothermicity increased with ψ resulting into enhanced agglomeration as confirmed from particle size distribution. Typically, the size of agglomerate varies from 0.59 to 1.56 μm. The XRD and FT-IR patterns reveal that the phase pure La0.6Sr0.4Co0.8Fe0.2O3-δ is formed at the ψ=2. The TEM particles size is 25 nm. La0.6Sr0.4Co0.8Fe0.2O3-δ powder shows the higher catalytic activity at about 426 °C. © 2015 Elsevier Ltd.
Synthesis of ZnO Nanorods/Carbon Nanofiber Composites Using Electrochemical Deposition for Efficient Supercapacitor Electrodes: Control of Nucleation and Growth of ZnO Nanorods
ZnO nanorods can be electrochemically deposited onto carbon nanofiber (CNF) substrates and used for high-performance supercapacitors. The conductive, three-dimensional structure of the CNF web allows for electrodeposition of the ZnO nanorods. Therefore, the properties of the CNF substrate, as well as the deposition conditions, directly relate to the deposition mechanisms of the ZnO nanorods. The ZnO nanorod structure can be modulated by tuning the current density, precursor concentration, and type of applied current. These parameters affect the nucleation and growth mechanisms, resulting in different structures of ZnO nanorods. Applying a pulsed current with a rest time (5 s) during electrodeposition produces denser and narrower ZnO nanorods than those prepared under a constant current. The additional ZnO thin film coating by atomic layer deposition (ALD) on the CNF substrate exhibits a different tendency of the deposition of ZnO nanorods by acting as a seed layer. Copyright © 2016 American Scientific Publishers All rights reserved.
Effects of Selective Polymerization Conditions on Physical Properties of Nanometer-Scale Silica/Polypyrrole Composites
Nanometer-scale (approximately 70 nm) silica/polypyrrole composites were synthesized using a selective polymerization based on an in situ-generated strong oxidizing agent (NO+ ions) on the silica surface. The effects of the concentrations of reactants (pyrrole monomer and NO2- ions) and the presence of additional dopant anions (Cl- or SO2-4) on the polypyrrole (ppy) content and electric conductivity of the silica/ppy composites are examined. It was found that the ppy content in the silica/ppy composites increased with the reactant concentration in the range of 0.02-0.2 M. It is revealed that employing additional dopant anions could be a promising way to improve the electrical conductivity of the composites. © 2015 Korean Chemical Society, Seoul & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Evidence of charge-density waves in the optical properties of SmNiC2
In this study, we have measured the optical reflectivity spectra of low-dimensional SmNiC2 (TC=18.5 K and TCDW=151 K) in the terahertz to ultraviolet frequency range at various temperatures. The optical conductivity spectra were transformed from the reflectivity data using the Kramers-Kronig relation. The optical conductivity of the normal state is well described by the Drude-Lorentz model assuming two bands. In nonmagnetic states below TCDW, two clean gaps opening on top of the Drude response are observed at around 500 and 750 cm-1. In the ferromagnetic state, the higher-side gap opening remains at the same frequency but the lower-side gap opening disappears, instead an additional absorption due to magnon gap formation is observed at around 70 cm-1. Â© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Efficient water management of composite membranes operated in polymer electrolyte membrane fuel cells under low relative humidity
High performance and durable electrolyte membrane operated in polymer electrolyte membrane fuel cells (PEMFCs) under low relative humidity (RH) has been achieved by incorporating various diameter sizes of mesoporous hygroscopic TiO<inf>2</inf> nanotubes (TNT) in a perfluorosulfonic acid (Nafion®) membrane. Porous TNTs with different tube diameters are synthesized by thermal annealing the electrospun polymer containing titanium precursor mat at 600°C under an air atmosphere. The diameter of the TNT is significantly controlled by changing the concentration of the precursor solution. Compared to a commercial membrane (Nafion, NRE-212), the Nafion-TNT-10 composite membrane operated under 100% RH at 80°C generates about 1.3 times higher current density at 0.6V, and 3.4 times higher maximum power density operated under dry conditions (18% RH at 80°C). In addition, the Nafion-TNT-10 composite membrane also exhibits stable and durable operation under dry conditions. The remarkably high performance of the Nafion-TNT-10 composite membrane is mainly attributed to the significant reduction of the ohmic resistance as well as the improvement of cathode catalyst utilization by incorporating TNTs, which greatly enhances the water retention and the water management capability through the membrane. Furthermore, Nafion-TNT membranes exhibit superior mechanical property. © 2015 Elsevier B.V.
MRPrimer: a MapReduce-based method for the thorough design of valid and ranked primers for PCR
Primer design is a fundamental technique that is widely used for polymerase chain reaction (PCR). Although many methods have been proposed for primer design, they require a great deal of manual effort to generate feasible and valid primers, including homology tests on off-target sequences using BLAST-like tools. That approach is inconvenient for many target sequences of quantitative PCR (qPCR) due to considering the same stringent and allele-invariant constraints. To address this issue, we propose an entirely new method called MRPrimer that can design all feasible and valid primer pairs existing in a DNA database at once, while simultaneously checking a multitude of filtering constraints and validating primer specificity. Furthermore, MRPrimer suggests the best primer pair for each target sequence, based on a ranking method. Through qPCR analysis using 343 primer pairs and the corresponding sequencing and comparative analyses, we showed that the primer pairs designed by MRPrimer are very stable and effective for qPCR. In addition, MRPrimer is computationally efficient and scalable and therefore useful for quickly constructing an entire collection of feasible and valid primers for frequently updated databases like RefSeq. Furthermore, we suggest that MRPrimer can be utilized conveniently for experiments requiring primer design, especially real-time qPCR. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.
Decanuclear Ln(10) Wheels and Vertex-Shared Spirocyclic Ln(5) Cores: Synthesis, Structure, SMM Behavior, and MCE Properties
The reaction of a Schiff base ligand (LH3) with lanthanide salts, pivalic acid and triethylamine in 1:1:1:3 and 4:5:8:20 stoichiometric ratios results in the formation of decanuclear Ln10 (Ln=Dy(1), Tb(2), and Gd (3)) and pentanuclear Ln5 complexes (Ln=Gd (4), Tb (5), and Dy (6)), respectively. The formation of Ln10 and Ln5 complexes are fully governed by the stoichiometry of the reagents used. Detailed magnetic studies on these complexes (1-6) have been carried out. Complex 1 shows a SMM behavior with an effective energy barrier for the reversal of the magnetization (Ueff)=16.12(8) K and relaxation time (τo)=3.3×10-5 s under 4000 Oe direct current (dc) field. Complex 6 shows the frequency dependent maxima in the out-of-phase signal under zero dc field, without achieving maxima above 2 K. Complexes 3 and 4 show a large magnetocaloric effect with the following characteristic values: -ΔSm=26.6 J kg-1 K-1 at T=2.2 K for 3 and -ΔSm=27.1 J kg-1 K-1 at T=2.4 K for 4, both for an applied field change of 7 T. Homometallic complexes: The reaction of a multidentate flexible Schiff base ligand (LH3; see figure) with [LnCl3]6 H2O affords homometallic decanuclear complexes, [Ln10(LH)10(κ2-Piv)10] (Ln=Dy, Tb, and Gd), and homometallic pentanuclear complexes, [Ln5(LH)4(μ2-η1η1Piv)4(η1Piv)(S)] (Ln=Dy, Tb, and Gd). The Dy3+ analogues exhibit single-molecule magnet (SMM) behavior, whereas the Gd3+ complexes show a significant magnetocaloric effect (MCE). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.