Human γδ T cell Recognition of lipid A is predominately presented by CD1b or CD1c on dendritic cells

<p>Abstract</p> <p>Background</p> <p>The γδ T cells serve as early immune defense against certain encountered microbes. Only a few γδ T cell-recognized ligands from microbial antigens have been identified so far and the mechanisms by which γδ T cells recognize these ligands remain unknown. Here we explored the mechanism of interaction of human γδ T cells in peripheral blood with Lipid A (LA).</p> <p>Results</p> <p>First, resting γδ T cells (mainly Vδ2 T cells) displayed a strong proliferative response to LA-pulsed monocyte-derived dendritic cells (moDC) and LA-pulsed paraformaldehyde-fixed moDC, but not to free LA in a TCR γδ-dependent manner. Second, anti-CD1b or anti-CD1c antibodies could block proliferative response of resting γδ T cells to LA-loaded moDC. Besides, only LA-loaded CD1b/CD1c-transfected C1R lymphoblastoma cells (CD1b-/CD1c-C1R) were able to stimulate the proliferation of human γδ T cells. Third, the expressions of both Toll-like receptor (TLR)2 and TLR4 on surface of LA-activated γδ T cells were upregulated, whereas only anti-TLR4 antibody could partially block their response to LA; Finally LA-loaded moDCs induce γδ T cells to produce Th1 cytokines, such as IFN-γ.</p> <p>Conclusion</p> <p>Taken together, we found a novel mechanism that human γδ T cells recognize LA in a CD1b- or CD1c-restricted manner in first response against Gram-bacteria, while the interaction between TLR4 on γδ T cells and LA might strengthen the subsequent response of γδ T cells.</p> <p>Reviewers</p> <p>This article was reviewed by Hao Shen, Youwen He (nominated by Dr. Laurence C Eisenlohr), Dr. Michael Lenardo and Dr. Pushpa Pandiyan.</p

pH-dependent gating mechanism of the Helicobacter pylori urea channel revealed by cryo-EM.

The urea channel of Helicobacter pylori (HpUreI) is an ideal drug target for preventing gastric cancer but incomplete understanding of its gating mechanism has hampered development of inhibitors for the eradication of H. pylori. Here, we present the cryo-EM structures of HpUreI in closed and open conformations, both at a resolution of 2.7 Å. Our hexameric structures of this small membrane protein (~21 kDa/protomer) resolve its periplasmic loops and carboxyl terminus that close and open the channel, and define a gating mechanism that is pH dependent and requires cooperativity between protomers in the hexamer. Gating is further associated with well-resolved changes in the channel-lining residues that modify the shape and length of the urea pore. Site-specific mutations in the periplasmic domain and urea pore identified key residues important for channel function. Drugs blocking the urea pore based on our structures should lead to a new strategy for H. pylori eradication

A ℘-order R-L high-pass filter modeled by local fractional derivative

Abstract As an important electronic device, filter is applied to all kinds of electronic products. In this paper, a new ℘ -order R-L High-pass filter (HPF) modeled by the local fractional derivative (LFD) is proposed for the first time. With the help of the local fractional Laplace transform (LFLT), we obtain the non-differentiable(ND) transfer function, and present the expressions of ND amplitude-frequency characteristic (AFC) and ND phase-frequency characteristics (PFC). The corresponding parameters and properties of the ℘ -order R-L HPF are also studied. What's interesting is that the ℘ -order R-L HPF becomesthe ordinary one in the exceptional case at ℘ = 1. The obtained results in this paper reveal the sufficiency of the local fractional derivative for analyzing the circuit systems in fractal space

Optimal design of piezoelectric vibration devices with constrained variable algorithm and FEA

Optimal design of piezoelectric vibration devices used in medical fields is a typical inequality constrained optimization problem. Constrained variable method, as the best algorithm to solve nonlinear constraint optimization problem is used in the optimal design of the piezoelectric devices. The object functions and constrain functions are automatically calculated with Finite Element Analysis software ANSYS, and the results will return to the main optimization program. Results show that compared with the given initial parameters, the vibration amplitude of the optimum piezoelectric vibration device is dramatically increased under the constraint that the stress concentration of the cutting tool is within limit. Experiments are also performed to measure the vibration amplitude. Results are in great agreement with the theoretical one

Mechanical rolling formation of interpenetrated lithium metal/lithium tin alloy foil for ultrahigh-rate battery anode

To achieve good rate capability of lithium metal anodes for high-energy-density batteries, one fundamental challenge is the slow lithium diffusion at the interface. Here we report an interpenetrated, three-dimensional lithium metal/lithium tin alloy nanocomposite foil realized by a simple calendering and folding process of lithium and tin foils, and spontaneous alloying reactions. The strong affinity between the metallic lithium and lithium tin alloy as mixed electronic and ionic conducting networks, and their abundant interfaces enable ultrafast charger diffusion across the entire electrode. We demonstrate that a lithium/lithium tin alloy foil electrode sustains stable lithium stripping/plating under 30mAcm(-2) and 5mAhcm(-2) with a very low overpotential of 20mV for 200 cycles in a commercial carbonate electrolyte. Cycled under 6C (6.6mAcm(-2)), a 1.0mAhcm(-2) LiNi0.6Co0.2Mn0.2O2 electrode maintains a substantial 74% of its capacity by pairing with such anode

Full-scale metamaterial window for building application

The research on acoustic metamaterials (AMMs) has progressed rapidly over the last decades. One of the applications is for noise control and airflow in duct-like systems. These are useful features for natural ventilation window design; however, the visual impact between indoor and outdoor environment, as another key factor of windows, makes the existing AMMs not directly useable for this application due to their geometrical complexity and size limitations. In this research, an AMM previously developed by the authors is exploited for full-scale window design. The AMM is packed only in the window frame so that the window transparency is not compromised. A broadband attenuation performance is obtained by the resonant unit cells constituting the AMM. The effect of the geometric variation on the window performance in terms of both acoustics and the airflow is analysed numerically through Finite Element Method (FEM) models. The performances of different AMM windows are evaluated and compared with those of conventional window designs. The simulation results show that this new AMM-based window design can overcome the limitations of the conventional windows, with great potential in real applications

Fatigue characterization of T300/924 polymer composites with voids under tension‐tension and compression‐compression cyclic loading

Fibrous polymer composites exhibit excellent properties such as high specific stiffness/strength and good fatigue performance. However, as inherent defects of polymer composites, voids have been reported to have an impact on their load‐bearing properties including fatigue resistance. In the interest of safety, the effect of voids on fatigue behaviours of composites should be understood and quantified. In this article, the effect of voids on the fatigue of T300/924 composites was evaluated in terms of their fatigue life, stiffness degradation, and cracks propagation under tension‐tension and compression‐compression loadings. The failure probability was assessed by Weibull distribution. Furthermore, crack measurement and fractographic analysis reveal that the effect of voids on the failure mechanisms of the material under various loading configurations could be different. Lastly, an analytical residual stiffness model was proposed, and a good correlation was obtained between the experimental data and the prediction results.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142461/1/ffe12721_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142461/2/ffe12721.pd

Development of a window system with acoustic metamaterial for air and noise control

To improve window performances in reducing noise and allowing for air exchange, most current approaches focus on techniques such as double glazed and ducted designs, generally leading to bulky designs, visually non-optimised, and with narrow-banded frequency. In this research, window systems based on acoustic metamaterials (AMMs) are developed, and both natural air ventilation and acoustic performances are evaluated. The systems incorporate bistable auxetic metamaterials and acoustic origami metacage designs which are particularly interesting for their reconfigurable and deployable nature. Several design cases with different design features are examined, and a specific design is then selected for a parametric analysis using Finite Element Method (FEM) aiming to optimise the acoustical performance. It is demonstrated that significant improvement in acoustic performance can be obtained in terms of Transmission Loss (TL). The use of AMMs could lead to designs with manifold merits over traditional windows, including compact size with deployability, easy reconfigurability and installation, and thus paving new direction in ventilation window design