Efficiency Droop in III-nitride LEDs

To dominate the illumination market, applications of high-power, group III-nitride light-emitting diodes (LEDs) with lower cost and higher efficiency at high injection current density must prevail. In this chapter, three possible origins of efficiency droop (including electron leakage, poor hole injection, and delocalization of carriers) in III-nitride LEDs are systematically summarized. To seek a more comprehensive understanding of the efficiency droop, experimental results based on commercialized LEDs are obtained to explain the physical mechanisms. Proposals for droop mitigation, such as (1) improving hole injection, and (2) increasing effective optical volume or reducing carrier density in the active region, are introduced. Finally, a simple expression for the effects of V-shaped pits on the droop is demonstrated

Ecological governance of Hainan coastline from the perspective of one health: A case study of the sustainable development of people’s livelihood after the coastline of Qionghai city was repopulated

Purposes It aims to discuss how to effectively carry out the ecological governance of the coastline of Qionghai City, Hainan Province under the concept of One Health [1] to promote the sustainable development of residents’ income and provide practical cases and theoretical references for the ecological governance of the Hainan Coastline. Methods Use field research and random interview methods to obtain relevant data and conduct quantitative analysis. Results and shortcomings Residents’ income has stable growth, water pollution control effects are outstanding, and the governance of air pollution is obvious. However, there are still problems such as serious degradation of coral reef ecosystems and lack of effective funding for ecological compensation, mainly due to the threat of insufficient capital investment and human activities. Conclusions It is recommended to improve the sustainable development capacity of the township governments, build a reasonable ecological compensation mechanism, accelerate the transformation of the township governments to the ecological government, increase the implementation of green GDP, form a virtuous circle of compared to achieve ecological environmental protection and economic development. Department decision -making provides a scientific basis

Spatial Combination Modeling Framework of Saturation-Excess and Infiltration-Excess Runoff for Semihumid Watersheds

There exist two types of direct runoff generation mechanisms in semihumid watersheds: saturation-excess mechanism and infiltration-excess mechanism. It has always been a difficult problem for event hydrological simulation to distinguish the two types of runoff processes. Based on the concept of dominant runoff processes, combined with GIS and RS techniques, this paper proposed an event-based spatial combination modeling framework and built two spatial combination models (SCMs) accordingly. The CN parameter and topographic index, both of which are widely used in hydrological researches, are adopted by the SCM to divide the entire watershed into infiltration-excess dominated (IED) areas and saturation-excess dominated (SED) areas. Dongwan watershed was taken as an example to test the performances of infiltration-excess model, saturation-excess model, and SCM, respectively. The results of parameter optimization showed that the parameter values and state variables of SCM are much more realistic than those of infiltration-excess model and saturation-excess model. The more accurate the divisions of infiltration-excess and saturation-excess dominated areas, the more realistic the SCM parameter values. The simulation results showed that the performance of SCM was improved in both calibration and validation periods. The framework is useful for flood forecasting in semihumid watersheds

Carbonized cellulose nanofibers as dielectric heat sources for microwave annealing 3D printed PLA composite

Filament fused fabrication (FFF) is an extrusion-based 3D printing technology for manufacturing thermoplastic components. One major obstacle facing 3D printed thermoplastic material is the reduced crystallinity resulting from a fast quench when material exiting the 3D printer hot nozzle solidifies quickly at the low-temperature platform, leading to weak mechanical performance. Here, we report an accelerated annealing strategy with the assistance of microwave heating, aiming to enhance crystallinity and mechanical performance of FFF 3D printed polylactic acid (PLA) composite. We selected naturally abundant cellulose fibers as precursors for producing carbonized cellulose nanofibers (CCNFs), and compounded CCNFs with PLA to produce bi-component filament for 3D printing final composite. After being irradiated with microwave, the embedded CCNFs in composite selectively absorbed microwave energy and generated heat. Subsequently, the localized heat transferred to the adjacent PLA regions, triggering amorphous PLA chains to repack and convert to new crystallites. In this work, annealing conditions, including heating method (i.e., oven annealing vs. microwave annealing), time (0–120 min), and temperature (80 vs. 120 °C), were systematically studied to understand the relevant effects on the resulting parameters including composite crystallinity and tensile strength. Microwave annealing method was also compared with conventional oven annealing method and results shows that microwave annealing significantly reduced the required annealing time to reach the maximum crystallinity and tensile strength. Notably, microwave annealing performed below cold crystallization temperature was exceptionally suitable to develop an optimized crystallinity and tensile strength for 3D printed PLA composite

Ailanthone targets p23 to overcome MDV3100 resistance in castration-resistant prostate cancer

Androgen receptor (AR) antagonist MDV3100 is the first therapeutic approach in treating castration-resistant prostate cancer (CRPC), but tumours frequently become drug resistant via multiple mechanisms including AR amplification and mutation. Here we identify the small molecule Ailanthone (AIL) as a potent inhibitor of both full-length AR (AR-FL) and constitutively active truncated AR splice variants (AR-Vs). AIL binds to the co-chaperone protein p23 and prevents AR's interaction with HSP90, thus resulting in the disruption of the AR-chaperone complex followed by ubiquitin/proteasome-mediated degradation of AR as well as other p23 clients including AKT and Cdk4, and downregulates AR and its target genes in PCa cell lines and orthotopic animal tumours. In addition, AIL blocks tumour growth and metastasis of CRPC. Finally, AIL possesses favourable drug-like properties such as good bioavailability, high solubility, lack of CYP inhibition and low hepatotoxicity. In general, AIL is a potential candidate for the treatment of CRPC

Deficient LRRC8A-dependent volume-regulated anion channel activity is associated with male infertility in mice

Ion channel-controlled cell volume regulation is of fundamental significance to the physiological function of sperm. In addition to volume regulation, LRRC8A-dependent volume-regulated anion channel (VRAC) activity is involved in cell cycle progression, insulin signaling, and cisplatin resistance. Nevertheless, the contribution of LRRC8A and its dependent VRAC activity in the germ cell lineage remain unknown. By utilizing a spontaneous Lrrc8a mouse mutation (c.1325delTG, p.F443*) and genetically engineered mouse models, we demonstrate that LRRC8A-dependent VRAC activity is essential for male germ cell development and fertility. Lrrc8a-null male germ cells undergo progressive degeneration independent of the apoptotic pathway during postnatal testicular development. Lrrc8a-deficient mouse sperm exhibit multiple morphological abnormalities of the flagella (MMAF), a feature commonly observed in the sperm of infertile human patients. Importantly, we identified a human patient with a rare LRRC8A hypomorphic mutation (c.1634G>A, p.Arg545His) possibly linked to Sertoli cell-only syndrome (SCOS), a male sterility disorder characterized by the loss of germ cells. Thus, LRRC8A is a critical factor required for germ cell development and volume regulation in the mouse, and it might serve as a novel diagnostic and therapeutic target for SCOS patients

Robust Exponential Synchronization of a Class of Chaotic Systems with Variable Convergence Rates via the Saturation Control

This article is concerned with the exponential synchronization of a class of the chaotic systems with external disturbance via the saturation control. Through appropriate coordinate transformation, the exponential synchronization is translated into the asymptotic stability of the error system. By using the Lyapunov stability theory, a novel sufficient condition which possesses the exponential convergence rate λ is presented. The rich choices of the exponential convergence rate λ turn our scheme more general than some existing approaches. Numerical simulations are employed to the Genesio chaotic system and the Coullet chaotic system to illustrate the ability and effectiveness of the presented approach