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The presence of Li2Si2O5 and LiAlSi4O10 could effectively improve the elastic modulus and transmittance of lithium disilicate(LD) glass-ceramics. Through synergistically modulation of the crystal content and grain size, we obtained high strength and high transmittance of LD glass-ceramics. The optimal sample had a high transmittance of 90.3%, the hardness was 7.72 GPa, the fracture toughness was 1.07 MPa·m1/2, and the elastic modulus was 103.1 GPa. [ABSTRACT FROM AUTHOR]

Fenpropathrin has been a commonly used insecticide to control agricultural and household insects over a few decades. Up to now, fenpropathrin residue in soil and water has been often determined due to its widespread use, which poses serious threat to environment and aquatic organisms. The potential of fenpropathrin to affect aquatic lives is still poorly understood. In this study, we used zebrafish (Danio rerio) embryo as an experimental model system to evaluate the toxicity of fenpropathrin to the development of zebrafish nervous system. Zebrafish embryos were separately exposed to fenpropathrin at the dose of 0.016 mg/L, 0.032 mg/L, 0.064 mg/L, starting at 6 h post-fertilizationhpf (hpf) up to 96 hpf. The results showed that fenpropathrin exposure gives rise to physiological, behavioral, and neurodevelopmental impairments in zebrafish embryos, including enhanced acetylcholinesterase (AChE) activity, abnormal swimming behavior, karyopyknosis in brain cells, increased intercellular space, and uneven migration of neuron in brain area. In addition, the expressions of genes concerning neurodevelopment and neurotransmitter system were inhibited following fenpropathrin exposure. We also found that fenpropathrin exposure distinctly induced oxidative stress by increasing reactive oxygen species (ROS) generation and inhibiting the production of antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD). Expectedly, some apoptosis-associated genes were induced and the apoptosis appeared in the brain and heart cells of zebrafish embryos. Moreover, fenpropathrin exposure also inhibited the expressions of genes in Nrf2 signaling pathway, such as heme oxygenase-1 (HO-1) and SOD. In summary, the results of this study indicate that oxidative stress-triggered apoptosis may be an underlying fundamental of fenpropathrin-induced neurotoxicity in zebrafish embryos. [ABSTRACT FROM AUTHOR]

Lead halide perovskites have exhibited excellent performance in solar cells, LEDs and detectors. Thermal properties of perovskites, such as heat capacity and thermal conductivity, have rarely been studied and corresponding devices have barely been explored. Considering the high absorption coefficient (104~105 cm−1), low specific heat capacity (296–326 J kg−1 K−1) and small thermal diffusion coefficient (0.145 mm2 s−1), herein we showcase the successful use of perovskite in optoacoustic transducers. The theoretically calculated phonon spectrum shows that the overlap of optical phonons and acoustic phonons leads to the up-conversion of acoustic phonons, and thus results in experimentally measured low thermal diffusion coefficient. The assembled device of PDMS/MAPbI3/PDMS simultaneously achieves broad bandwidths (−6 dB bandwidth: 40.8 MHz; central frequency: 29.2 MHz), and high conversion efficiency (2.97 × 10−2), while all these parameters are the record values for optoacoustic transducers. We also fabricate miniatured devices by assembling perovskite film onto fibers, and clearly resolve the fine structure of fisheyes, which demonstrates the strong competitiveness of perovskite based optoacoustic transducers for ultrasound imaging. Lead halide perovskites are widely used e.g. in solar cells and LEDs, but devices based on thermal properties have received little attention. Here, the authors take advantage of the thermal properties to fabricate an optoacoustic transducer with both broad bandwidth and high conversion efficiency. [ABSTRACT FROM AUTHOR]

Pr doped ZnO quantum dots (QDs) were successfully synthesized by sol-gel process. X-ray diffraction (XRD) and X-ray Phtoelectron spectroscopy (XPS) were used to analyze the microstructure variation of ZnO QDs and the chemical environment of Pr with increasing Pr doping concentrations. Most of Pr ions distribute on the surface of ZnO QDs while a few of them penetrate into the ZnO lattice to substitute Zn which causes the lattice distortion and the change of the crystal size. With increasing concentration of Pr ions, the crystal size of ZnO QDs firstly increases and then decreases meanwhile the amorphization gradually increases. New Pr-O-Zn bonds formed after Pr doping and Pr ions have at least two chemical bonding environments: one is Pr-O-Zn bond and the other is Pr-O bond surrounded by oxygen vacancies. [ABSTRACT FROM AUTHOR]

CdSe quantum dots (QDs) doped glasses have been widely investigated for optical filters, LED color converter and other optical emitters. Unlike CdSe QDs in solution, it is difficult to passivate the surface defects of CdSe QDs in glass matrix, which strongly suppress its intrinsic emission. In this study, surface passivation of CdSe quantum dots (QDs) by Cd1−xZnxSe shell in silicate glass was reported. An increase in the Se/Cd ratio can lead to the partial passivation of the surface states and appearance of the intrinsic emission of CdSe QDs. Optimizing the heat-treatment condition promotes the incorporation of Zn into CdSe QDs and results in the quenching of the defect emission. Formation of CdSe/Cd1−xZnxSe core/graded shell QDs is evidenced by the experimental results of TEM and Raman spectroscopy. Realization of the surface passivation and intrinsic emission of II-VI QDs may facilitate the wide applications of QDs doped all inorganic amorphous materials. [ABSTRACT FROM AUTHOR]