[en] The role of microRNA (miRNA) in proliferative vitreoretinopathy (PVR) progression has not been studied extensively, especially in retinal pigment epithelial–mesenchymal transition (EMT) which is the main reason for formation of PVR. In this study, we first investigated the miRNA expression profile in transforming growth factor beta 1 (TGF-β1) mediated EMT of ARPE-19 cells. Among the five changed miRNAs, miR-29b showed the most significant downregulation. Enhanced expression of miR-29b could reverse TGF-β1 induced EMT through targeting Akt2. Akt2 downregulation could inhibit TGF-β1-induced EMT. Furthermore, inhibition of miR-29b in ARPE-19 cells directly triggered EMT process, which characterized by the phenotypic transition and the upregulation of α-smooth muscle actin (α-SMA) and downregulation of E-cadherin and zona occludin-1 (ZO-1) with increased cell migration. Akt2-shRNA also inhibited miR-29 inhibitor-induced EMT process. These data indicate that miR-29b plays an important role in TGF-β1-mediated EMT in ARPE-19 cells by targeting Akt2. - Highlights: • MiR-29b expression is decreased in TGF-β1-induced EMT of ARPE-19 cells. • MiR-29b inhibits TGF-β1-induced EMT in ARPE-19 cells. • MiR-29b inhibitor induces EMT in ARPE-19 cells. • Akt2 is the target for miR-29b. • Downregulation of Akt2 prevents TGF-β1-induced EMT of ARPE-19 cells.

[en] Highlights: • First reported overexpression of Snail in RPE cells could directly trigger EMT. • Further confirmed the regulator role of Snail in RPE cells EMT in vitro. • Snail may be a potential therapeutic target to prevent the fibrosis of PVR. - Abstract: Snail transcription factor has been implicated as an important regulator in epithelial–mesenchymal transition (EMT) during tumourigenesis and fibrogenesis. Our previous work showed that Snail transcription factor was activated in transforming growth factor β1 (TGF-β1) induced EMT in retinal pigment epithelial (RPE) cells and may contribute to the development of retinal fibrotic disease such as proliferative vitreoretinopathy (PVR). However, whether Snail alone has a direct role on retinal pigment epithelial–mesenchymal transition has not been investigated. Here, we analyzed the capacity of Snail to drive EMT in human RPE cells. A vector encoding Snail gene or an empty vector were transfected into human RPE cell lines ARPE-19 respectively. Snail overexpression in ARPE-19 cells resulted in EMT, which was characterized by the expected phenotypic transition from a typical epithelial morphology to mesenchymal spindle-shaped. The expression of epithelial markers E-cadherin and Zona occludin-1 (ZO-1) were down-regulated, whereas mesenchymal markers a-smooth muscle actin (a-SMA) and fibronectin were up-regulated in Snail expression vector transfected cells. In addition, ectopic expression of Snail significantly enhanced ARPE-19 cell motility and migration. The present data suggest that overexpression of Snail in ARPE-19 cells could directly trigger EMT. These results may provide novel insight into understanding the regulator role of Snail in the development of retinal pigment epithelial–mesenchymal transition

[en] Highlights: • CuInS₂ powders were synthesized by mechanochemical process. • No intermetallic phase appears before the self-propagating combustion. • Morphology evolution were observed and homogeneous CuInS₂ particles were obtained. • The mechanism for mechanically induced self-propagating reaction was discussed. • CuInS₂ has a broad absorption over visible light and near-infrared region. - Abstract: CuInS₂ powders were synthesized by mechanochemical process from copper, indium and sulfur powders. A self-propagating combustion occurred during the milling process. Phase structure, morphology evolution and component uniformity of Cu–In–S system have been studied by X-ray diffraction, scanning electron microscope and energy dispersive analysis, respectively. Optical property of ball milled CuInS₂ has been detected by UV–Vis spectroscopy. The results show that there is no intermetallic phase was observed before the self-propagating combustion though morphology changed obviously during this stage. The detected composition of mixed powder converges toward the original proportion with increased milling as the particle sizes decreased. Homogeneous CuInS₂ particles less than 5 μm are obtained after milling 120 min. The reason of mechanically induced self-propagating reaction occurs during milling in this system is also discussed. The UV–Vis absorption spectrum shows the milled CuInS₂ has a broad absorption over the entire visible light and extending into the near-infrared region and its band gap is 1.52 eV

[en] In order to study the MAC layer protocol in the wireless sensor network under the actual channel condition, the field programmable gate array (FPGA) hardware circuit is used to provide a dual-priority implementation scheme for the persistence carrier sense multiple access (CSMA) protocol. According to the characteristics of each node in the network, analyzes the system throughput and energy consumption, and the FPGA is used to overcome the shortcomings of the existing implementation scheme and the article combines the actual application, changes the single channel mode, and realizes the dual channel data transmission. Finally, the simulation tests the correctness of the design. (paper)

[en] We propose a method theoretically to break the diffraction limit and to improve the resolution in all three dimensions for fluorescence emission difference microscopy. We produce two kinds of hollow focal spot by phase modulation. By incoherent superposition, these two kinds of focal spot yield a 3D hollow focal spot. The optimal proportion of these two kinds of spot is given in the paper. By employing 3D hollow focal spot, super-resolution image can be yielded by means of fluorescence emission difference microscopy, with resolution enhanced both laterally and axially. According to computation result, size of point spread function of three-dimensional super-resolution imaging is reduced by about 40% in all three spatial directions with respect to confocal imaging

[en] High energy X-ray radiographs reconstruction is a typical nonlinear process. However, most of the current reconstruction methods are based on a linear approximation model, which uses optical depth images for reconstruction. As radiographs are convolved by the system blur, images reconstructions with these algorithms are blurred, especially at edges. In this paper, a nonlinear least squares reconstruction model for transmittance images is established and optimized by the Levenberg–Marquardt algorithm assuming that the system blur is known. The numerical experiments show that the reconstruction error of this approach is greatly reduced and the edges sharpness is significantly improved, compared with the traditional constrained conjugate gradient method and the trust region reflective method. For images contaminated by blur and low noise, the reconstruction is still improved and acceptable even when an inaccurate system blur is used. Furthermore, we propose an idea of rectifying the system blur measured by experiments. Our reconstruction method is practical in deconvolution and shows a promising prospect in high energy X-ray radiographs reconstruction.

[en] α-NaMnO₂ contains layers of high spin Mn³⁺ (d⁴) ions parallel to the ab plane, and Mn³⁺ layers alternate with Na⁺ ions layers along the c direction. To explore the interesting two-dimensional spin correlations and one-dimensional magnetic excitations, we carefully studied the electronic and magnetic properties of α-NaMnO₂ via density functional theory calculations. By evaluating the intra-layer interactions J₁-J₄ as well as the inter-layer exchanges J₅ and J₆ through performing mapping analysis, we found that α-NaMnO₂ displays typical two-dimensional spin correlations, which are dominated by the intra-chain interaction J₁ and the inter-chain interaction J₃ (J₃/J₁ ≈ 0.21). Interestingly, both the strong spin exchange interactions J₁ and J₃ come from supersuperexchange (SSE), other than superexchange (SE). Also, due to the topology of the lattices, the magnetic excitation is dominated by the intra-chain interaction J₁, leading to the one-dimensional model.

[en] Highlights: • Realizing higher enhancement for core's emission for core-shell UCNPs. • The high performance narrowband NIR photodetector. -- Abstract: Employing lanthanide doped upconversion nanoparticles (UCNPs) as near-infrared absorbing photoactive materials is a feasible conception for constructing high efficient and stable narrowband wavelength-selective photodetectors, but limited by its upconversion luminescence efficiency. Herein, we experimentally and theoretically demonstrate upconversion luminescence (UCL) enhancement in monolayer UCNPs using plasmon semiconductor NPs (Cs_xWO₃) and further explore its narrowband near-infrared photodetection application. The UCL improvement of 144 folds in Cs_xWO₃/NaYF₄/NaYF₄:Yb³⁺, Er³⁺ hybrid was realized with the optimized spacer thickness (15 nm) and monolayer UCL. More than three orders enhancement was obtained via the semiconductor plasmon combined with core-shell UCNPs in both Cs_xWO₃/NaYF₄/monolayer-NaYF₄:Yb³⁺, Er³⁺@NaYF₄:Yb³⁺, Tm³⁺ and Cs_xWO₃/NaYF₄ /monolayer-NaYF₄:Yb³⁺, Tm³⁺@NaYF₄:Yb³⁺, Er³⁺. Interestingly, the higher enhancement of core's emissions was recorded in core-shell UCNPs by coupling with Cs_xWO₃ NPs. The excitation field amplification dominates the high UCL enhancement, revealed by the UCL dynamics and the calculated electric field intensity. Finally, the high performance narrow photodetectors for 980 nm is constructed employing MAPbI₃/Cs_xWO₃/NaYF₄/NaYF₄:Yb³⁺, Er³⁺@NaYF₄:Yb³⁺, Tm³⁺ hybrids, with narrow line width of 20 nm, high responsivity of 0.33 A/W, detectivity of 4.5 × 10¹⁰ Jones, and short response time of 180 ms, which is much better than the previous photodetectors. This finding provides keen approach for developing high efficient/performance UCNPs and narrowband photodetectors.

[en] The alternation from bipolar to unipolar resistive switching is observed in perovskite La_0.01Sr_0.99TiO₃ thin films. These two switching modes can be activated separately depending on the compliance current (I_comp) during the electro-forming process: with a higher I_comp (5 mA) the unipolar resistance switching behavior is measured, while the bipolar resistance switching behavior is observed with a lower I_comp (1 mA). On the basis of I—V characteristics, the switching mechanisms for the URS and BRS modes are considered as being a change in the Schottky-like barrier height and/or width at the Pt/La-SrTiO₃ interface and the formation and disruption of conduction filaments, respectively

[en] Lanthanide (Ln) group elements have been attracting considerable attention owing to the distinct optical properties. The crystal-field surroundings of Ln ions in the host materials can determine their energy level splitting, which is of vital importance to tailor their optical properties. 2D MoS₂ single crystals were utilized as the host material to embed Eu³⁺ and energy-level splitting was achieved for tuning its photoluminescence (PL). The high anisotropy of the 2D host materials makes them distort the degenerate orbitals of the Ln ions more efficiently than the symmetrical bulk host materials. A significant red-shift of the PL peak for Eu³⁺ was observed. The strategy for tailoring the energy level splitting of Ln ions by the highly designable 2D material crystal field provides a new method to extend their optical properties. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)