Dendritic cells (DCs) are key components of the immune system, serving as antigen‐presenting cells to activate adaptive immunity. Whereas mature DCs promote immune responses, immature DCs induce or maintain immunological tolerance by downregulating T‐cell responses. Therefore, DCs are potent antigen (Ag)‐presenting cells in the immune system. MicroRNAs are noncoding RNAs that posttranscriptionally regulate mRNA by binding the 3′‐untranslated region (UTR) of these molecules, modulating their expression. Many recent studies have suggested a potential role of miRNAs in DCs maturation and differentiation, but the exact mechanisms governing this process are unclear. How and whether miR‐199a‐3p affects DC maturation has not been investigated. Here, we found that MiR‐199a‐3p levels are correlated with DC maturation, inflammatory cytokine secretion, and PI3K/AKT/NF‐κB signaling pathway activity. In addition, we analyzed the stimulation of regulatory T‐cells by DCs. Through this work, we determined CD86 to be targeted by miR‐199a‐3p, thereby linking it to DC maturation. miR‐199a‐3p therefore directly inhibits CD86 expression via 3′‐UTR targeting, subsequently prolonging allograft survival in a mouse heart transplantation model. miR‐199a‐3p over‐expression may therefore be a potential therapeutic strategy for use in organ transplantation or patients with autoimmune diseases.

The dry bias of MEMS humidity sensor induced by solar radiation heating seriously affects the accuracy of the relative humidity (RH) measurement. To solve this problem, this paper presents a novel numerical analysis method for the error correction of RH based on computational fluid dynamics (CFD). Firstly, considering the solar radiation, the distribution of temperature field of MEMS humidity sensor is simulated from the ground to 32km altitude by using CFD soft under the boundary condition of fluid-solid coupled heat transfer. Secondly, the numerical analysis model of RH is put forward for solar radiation dry bias (SRDB) correction based on the working principle of the MEMS capacitive humidity sensor and the definition of RH. The results of numerical analysis show that the error of RH caused by solar radiation is nonlinearly increased with the altitude. Meanwhile the errors decrease with the reflectivity of sensor or of solder point increase. The simulation data also indicate that the SRDB can be reduced by improving the reflectivity of sensor or of solder point, adopting the substrate material with high thermal conductivity or choosing the suitable thickness of sensor. However, the SRDB should be corrected, for it still is more than 20% under the low atmospheric pressure. In this paper, the method based on fluid dynamics simulation provides a new way to correct the error of radiosonde MEMS humidity measurement caused by solar radiation heating.

The elastic mechanical properties of silicon nanocantilevers are of prime importance in biotechnology and nanoelectromechanical system (NEMS) applications. In order to make these applications reliable, the exact evaluation of the effect of the undercut on the mechanical properties of silicon nanocantilevers is essential and critical. In this paper, a numerical-experimental method for determining the effect of the undercut on resonant frequencies and Young’s modulus of silicon nanocantilevers is proposed by combining finite element (FE) analysis and dynamic frequency response tests by using laser Doppler vibrometer (LDV) as well as static force-displacement curve test by using an atomic force microscope (AFM). Silicon nanocantilevers test structures are fabricated from silicon-on-insulator (SOI) wafers by using the standard complementary metal-oxide-semiconductor (CMOS) lithography process and anisotropic wet-etch release process based on the critical point drying, which inevitably generating the undercut of the nanocantilever clamping. Combining with three-dimensional FE numerical simulations incorporating the geometric undercut, the dynamic resonance tests demonstrate that the undercut obviously reduces resonant frequencies of nanocantilevers due to the fact that the undercut effectively increases the nanocantilever length by a correct value ΔL. According to a least-square fit expression including ΔL, we extract Young’s modulus from the measured resonance frequency versus the effective length dependency and find that Young’s modulus of a silicon nanocantilever with 200-nm thickness is close to that of bulk silicon. However, when we do not consider the undercut ΔL, the obtained Young's modulus is decreased 39.3%. Based on the linear force-displacement response of 12μm long and 200nm thick silicon nanocantilever obtained by using AFM, our extracted Young’s modulus of the [110] nanocantilever with and without undercut is 169.1GPa and 133.0GPa, respectively. This error reaches 21.3%. Our work reveals that the effect of the undercut on the characterization of the mechanical properties of nanocantilevers with dynamic and static test must be carefully considered.