Halide perovskites are a compelling candidate for the next generation of clean-energy-harvesting technologies owing to their low cost, facile fabrication and outstanding semiconductor properties. ...However, photovoltaic device efficiencies are still below practical limits and long-term stability challenges hinder their practical application. Current evidence suggests that strain in halide perovskites is a key factor in dictating device efficiency and stability. Here we outline the fundamentals of strain within halide perovskites relevant to photovoltaic applications and rationalize approaches to characterize the phenomenon. We examine recent breakthroughs in eliminating the adverse impacts of strain, enhancing both device efficiencies and operational stabilities. Finally, we discuss further challenges and outline future research directions for placing stress and strain studies at the forefront of halide perovskite research. An extensive understanding of strain in halide perovskites is needed, which would allow effective strain management and drive further enhancements in efficiencies and stabilities of perovskite photovoltaics.
Postoperative recurrence and metastasis have crucial roles in the poor prognosis of gastric cancer patients. Previous studies have indicated that gastric cancer originates from cancer stem cells ...(CSCs), and some investigators have found that a particular subset of CSCs possesses higher metastatic capacity. However, the specific mechanism remains uncertain. In the present study, we aimed to explore the biological functions of the inflammatory cytokine interleukin-17 (IL-17) in gastric cancer metastasis and the distinct IL-17-induced transformation of quiescent gastric CSCs. Our results showed that invasive gastric CSCs were CD26+ and CXCR4+ and were closely associated with increased metastatic ability. The quiescent gastric CSCs, which were CD26- and CXCR4-, were exposed to appropriate concentrations of IL-17; this resulted in the decreased expression of E-cadherin and the increased expression of vimentin and N-cadherin. In addition, the upregulation of IL-17 both in vitro and in vivo resulted in a significant induction of invasion, migration and tumor formation ability in gastric CSCs compared with the control group, which was not treated with IL-17. Further experiments indicated that the activation of the downstream phosphorylated signal transducer and activator of transcription 3 (STAT3) transcription factor pathway was facilitated by IL-17. On the contrary, the downregulation of STAT3 by the specific inhibitor Stattic significantly reversed the IL-17-induced epithelial-mesenchymal transition (EMT)-associated properties of quiescent gastric CSCs. Moreover, tumorigenesis and metastasis were suppressed. Taken together, we suggest that IL-17 is positively correlated with the transformation of quiescent gastric CSCs into invasive gastric CSCs and that targeting IL-17 may emerge as a possible novel therapeutic strategy for gastric cancer.
Grain boundaries play a key role in the performance of thin‐film optoelectronic devices and yet their effect in halide perovskite materials is still not understood. The biggest factor limiting ...progress is the inability to identify grain boundaries. Noncrystallographic techniques can misidentify grain boundaries, leading to conflicting literature reports about their influence; however, the gold standard – electron backscatter diffraction (EBSD) – destroys halide perovskite thin films. Here, this problem is solved by using a solid‐state EBSD detector with 6000 times higher sensitivity than the traditional phosphor screen and camera. Correlating true grain size with photoluminescence lifetime, carrier diffusion length, and mobility shows that grain boundaries are not benign but have a recombination velocity of 1670 cm s−1, comparable to that of crystalline silicon. Amorphous grain boundaries are also observed that give rise to locally brighter photoluminescence intensity and longer lifetimes. This anomalous grain boundary character offers a possible explanation for the mysteriously long lifetime and record efficiency achieved in small grain halide perovskite thin films. It also suggests a new approach for passivating grain boundaries, independent of surface passivation, to lead to even better performance in optoelectronic devices.
Electron backscatter diffraction (EBSD) combined with carrier lifetime, mobility, and diffusion length measurements, shows that optical and scanning electron microscopy images cannot accurately predict grain boundary positions or their resulting properties. Grain boundaries passivated by amorphous perovskite display increased photoluminescence lifetime and intensity. This suggests that crystallographic (not only chemical) effects play an important role in halide perovskite grain boundary properties.
Objectives
Talaromycosis is an invasive mycosis endemic to Southeast Asia. This study aimed to investigate the epidemiology, clinical features and prognostic factors of HIV‐associated talaromycosis ...in Guangdong, China.
Methods
We retrospectively evaluated HIV patients hospitalized with histopathology‐ or culture‐confirmed talaromycosis between 2011 and 2017. Factors associated with poor prognosis were identified using logistic regression.
Results
Overall, 1079 patients with HIV‐associated talaromycosis were evaluated. Both the number and prevalence of talaromycosis among HIV admissions increased from 125 and 15.7% in 2011 to 253 and 18.8% in 2017, respectively, reflecting the increase in HIV admissions. Annual admissions peaked during the rainy season between March and August. Common clinical manifestations included fever (85.6%), peripheral lymphadenopathy (72.3%), respiratory symptoms (60.8%), weight loss (49.8%), skin lesions (44.5%) and gastrointestinal symptoms (44.3%). Common laboratory abnormalities were hypoalbuminaemia (98.6%), anaemia (95.6%), elevated aspartate aminotransferase level (AST) (76.9%), elevated alkaline phosphatase level (55.8%) and thrombocytopenia (53.7%). The median CD4 count was 9 cells/μL. Talaromyces marneffei was isolated from blood and bone marrow cultures of 66.6% and 74.5% of patients, respectively. The rate increased to 86.6% when both cultures were performed concurrently. At discharge, 14% of patients showed worsening conditions or died. Leucocytosis, thrombocytopenia, elevated AST, total bilirubin, creatinine and azole monotherapy independently predicted poor prognosis.
Conclusions
The incidence of HIV‐associated talaromycosis has increased in Guangdong with the high HIV burden in China. Skin lesions were seen in less than half of patients. Induction therapy with azole alone is associated with higher mortality. Findings from this study should help to improve treatment of the disease.
This paper presents a vibration control strategy for a two-link Flexible Joint Manipulator (FJM) with a Hexapod Active Manipulator (HAM). A dynamic model of the multi-body, rigid–flexible system ...composed of an FJM, a HAM and a spacecraft was built. A hybrid controller was proposed by combining the Input Shaping (IS) technique with an Adaptive-Parameter Auto Disturbance Rejection Controller (APADRC). The controller was used to suppress the vibration caused by external disturbances and input motions. Parameters of the APADRC were adaptively adjusted to ensure the characteristic of the closed loop system to be a given reference system, even if the configuration of the manipulator significantly changes during motion. Because precise parameters of the flexible manipulator are not required in the IS system, the operation of the controller was sufficiently robust to accommodate uncertainties in system parameters. Simulations results verified the effectiveness of the HAM scheme and controller in the vibration suppression of FJM during operation.
•FJM׳s hybrid controller with IS and APADRC is proposed.•By APADRC, closed loop system of FJM will be consistent with a reference system, even if the configuration of FJM is changed.•Hybrid controller design is simplified by using the HAM as well as increases the FJM׳s vibration control capability.
Based on theoretical analysis, finite element simulation and experimental verifications, we have systematically investigated evolution, hybridization and decoupling of multiple acoustic wave modes ...and vibration patterns generated from piezoelectric film acoustic wave devices fabricated on flexible thin foils/plates. ZnO piezoelectric films deposited on flexible and bendable Al foil and plates were selected for this particular study. The ZnO/Al acoustic wave devices were chosen with wavelengths varied from 12 to 800 μm, ZnO film thickness from 2 to 10 μm and Al foil/plate thickness from 10 to 600 μm. Multiple acoustic wave modes (including symmetrical and asymmetrical Lamb waves, Rayleigh waves and higher harmonic/Sezawa wave modes) were generated, hybridized occasionally with each other, and then easily decoupled by changing the ratios of the substrate/film thicknesses to wavelengths. Ratios between device wavelength and substrate/film thickness have been identified to be the dominant parameter in determining the evolution and hybridization of multiple wave modes and their vibration patterns, which provide useful design guidance for both sensing and microfluidic applications using these flexible and bendable acoustic wave devices.
•Evolution, hybridization and decoupling of multiple acoustic wave modes are investigated using FEA and experimental methods•Symmetrical and asymmetrical Lamb waves, Rayleigh waves and Sezawa waves are generated from thin film acoustic wave devices•Ratios between device wavelength and thickness are identified dominant in evolution and hybridization of wave modes•Design methodology are applicable for sensing and microfluidic applications using flexible/bendable acoustic wave devices
Chaetomiaceae comprises phenotypically diverse species, which impact biotechnology, the indoor environment and human health. Recent studies showed that most of the traditionally defined genera in ...Chaetomiaceae are highly polyphyletic. Many of these morphology-based genera, such as Chaetomium , Thielavia and Humicola , have been redefined using multigene phylogenetic analysis combined with morphology; however, a comprehensive taxonomic overview of the family is lacking. In addition, the phylogenetic relationship of thermophilic Chaetomiaceae species with non-thermophilic taxa in the family is largely unclear due to limited taxon sampling in previous studies. In this study, we provide an up-to-date overview on the taxonomy and phylogeny of genera and species belonging to Chaetomiaceae , including an extensive taxon sampling of thermophiles. A multigene phylogenetic analysis based on the ITS (internal transcribed spacers 1 and 2 including the 5.8S nrDNA), LSU (D1/D2 domains of the 28S nrDNA), rpb2 (partial RNA polymerase II second largest subunit gene) and tub2 (β-tubulin gene) sequences was performed on 345 strains representing Chaetomiaceae and 58 strains of other families in Sordariales . Divergence times based on the multi-gene phylogeny were estimated as aid to determine the genera in the family. Genera were delimited following the criteria that a genus must be a statistically well-supported monophyletic clade in both the multigene phylogeny and molecular dating analysis, fall within a divergence time of over 27 million years ago, and be supported by ecological preference or phenotypic traits. Based on the results of the phylogeny and molecular dating analyses, combined with morphological characters and temperature-growth characteristics, 50 genera and 275 species are accepted in Chaetomiaceae . Among them, six new genera, six new species, 45 new combinations and three new names are proposed. The results demonstrate that the thermophilic species fall into seven genera ( Melanocarpus , Mycothermus , Remersonia , Thermocarpiscus gen. nov. , Thermochaetoides gen. nov. , Thermothelomyces and Thermothielavioides ). These genera cluster in six separate lineages, suggesting that thermophiles independently evolved at least six times within the family. A list of accepted genera and species in Chaetomiaceae , together with information on their MycoBank numbers, living ex-type strains and GenBank accession numbers to ITS, LSU, rpb2 and tub2 sequences is provided. Furthermore, we provide suggestions how to describe and identify Chaetomiaceae species.
Coal seam gas will seriously threaten the safety of mining. The stability of drainage borehole determines the safety of both mining and utilization of coal seam gas. However, the borehole will ...collapse, leading to the failure of gas drainage. A porous and firm low-cost aerated concrete-based material for borehole protection is proposed as a solution. Under high confining pressure, the mechanism of pore distribution of aerated concrete-based material on its properties is still unclear. In this work, the experiment and molecular dynamics simulation are combined to analyze how pore distribution determines its permeability and compressive strength. The effect of water-to-cement ratio on aerated concrete is first investigated by pore distribution, compressive strength, and permeability measures. The experimental results of optimal water-to-cement ratio of 0.6 agree with the existing experimental results of 0.54–0.64. Further, the orthogonal experiment is used to investigate the relationship between pore distribution and its permeability by doping fly-ash. It is found that under the same water-to-cement ratio, the doped fly-ash shows a limited effect on the permeability of aerated concrete. The pore in the range from 500 to 1500
μ
m
mainly contributes to the flow rate. The optimal mixture of doped aerated concrete is water-to-cement ratio of 0.6 and mass fraction of doped fly-ash of 40%. Moreover, the absorption/desorption effects of methane molecules are illustrated by molecular dynamics simulation. It is found that the flow rate of aerated concrete will be enhanced by hydrophobic fly-ash nanoparticles. The present work can inspire further mixture design and pave the way for the development of aerated concrete-based material with high porosity and compressive strength at high confining pressure.
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