The yellow luminescence (YL) in as-grown high-resistance (HR) and unintentional-doped (UID) GaN films grown by metal organic chemical vapor deposition has been investigated by means of photoluminescence and monoenergetic positron annihilation spectroscopy. It is found there is stronger YL in UID-GaN with higher concentration of gallium vacancy (VGa), suggesting that VGa-involved defects are the origin responsible for the YL in UID-GaN. Contrastly, there is much stronger YL in HR-GaN that is nearly free from VGa, suggesting that there is another origin for the YL in HR-GaN, which is thought as the carbon-involved defects. Furthermore, it is found that the HR-GaN film with shorter positron diffusion length Ld exhibits stronger YL. It is suggested that the increased wave function overlap of electrons and holes induced by the extremely strong space localization effect of holes deduced from the short Ld is the vital factor to enhance the YL efficiency in HR-GaN.

Background:Apoptosis of endothelial cells (ECs) plays a key role in the development of atherosclerosis and there are also evidence indicated that phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a viable target in therapeutic approaches to prevent vascular ECs apoptosis. Aberrant miR-106b-5p expression has been reported in the plasma of patients with unstable atherosclerotic plaques. However, the role and underlying mechanism of miR-106-5p in the genesis of atherosclerosis have not been addressed. In this study, we explored the anti-apoptotic role of miR-106-5p by regulating PTEN expression in vascular ECs.Methods:Real-time reverse transcription polymerase chain reaction (RT-PCR) was performed to detect the expression levels of miR-106b-5p in human atherosclerotic plaques and normal vascular tissues. Human umbilical vein endothelial cells (HUVEC) were transfected with miR-106b-5p mimic or negative control mimic, and apoptosis was induced by serum starvation and tumor necrosis factor-α (TNF-α) treat. Western blotting and real-time RT-PCR experiments were used to detect PTEN expression levels and TNF-α-induced apoptosis was evaluated by the activation of caspase-3 and cell DNA fragmentation levels in HUVEC.Results:The expression of miR-106b-5p was significantly downregulated in plaques than in normal vascular tissues. TNF-α significantly downregulated miR-106b-5p expression levels and upregulated activation of caspase-3 and cell DNA fragmentation levels in HUVEC. Overexpression of miR-106b-5p with miR-106b-5p mimic inhibited PTEN expression and TNF-α-induced apoptosis in HUVEC. Luciferase reporter assays confirmed that miR-106b-5p binds to PTEN mRNA 3’ untranslated region site.Conclusion:MiR-106b-5p could inhibit the expression of PTEN in vascular ECs, which could block TNF-α-induced activation of caspase-3, thus prevent ECs apoptosis in atherosclerosis diseases.

No abstract

Unlike commercial buildings, many school buildings in China are designed for natural or mechanical ventilation to fulfill thermal comfort without HVAC systems. In hot weather, due to too many students having classes at same time, the thermal conditions in classrooms were so poor to affect student's learning, especially for large lecture rooms. Therefore, it is important to study the ventilation conditions of school buildings and to explore effective means to improve the ventilation design of school buildings. This study was conducted using Fluent CFD software to improve the ventilation performance in one classroom. The field study was carried to collect the actual data of boundary conditions for CFD simulation. In this study, four different ventilation systems were simulated, compared and analyzed. Based on the simulation data, it is found that double rows windows can help to improve the thermal comfort conditions most efficiently, and so do exhaust fans and ceiling fans. But ceiling fans can improve the environment of occupied zones better.

Suspended nano/microstructures on semiconductor surfaces that can manage light are attractive for various on‐chip and efficiency‐enhanced optoelectronics. Hybrid halide perovskites have shown considerable potential for optoelectronic and photonic applications. However, the ionic and soft lattices of perovskites are sensitive to polar solvents, photons, and heat, limiting the post‐processing of suspended microstructures. Herein, a solution‐processed selective area homoepitaxial growth (SAEG) method is introduced to create well‐ordered, suspended microstructure arrays on the surface of MAPbX3 (X = Br, Cl) single‐crystalline thin films. The suspended micro‐arrays exhibit single crystalline structures and 11.2 fold photoluminescence enhancement compared to the thin‐film substrates. The success of SAEG lies in the making use of perovskite supersaturated HX aqueous solutions that not only repair surface defects induced by lithography but also satisfy homoepitaxial growth kinetics. This study paves a pathway for the fabrication of cost‐effective perovskite surface‐suspended microstructures for efficiency‐enhanced and on‐chip optoelectronic devices.