Search

Wide-bandgap (WBG) perovskite solar cells (PSCs) play a crucial role in tandem devices. However, the severe nonradiative recombination that occurs at the interface between perovskite and electron transport layer (ETL) leads to excessive open-circuit voltage (VOC) loss, which hinders the further improvement of the photovoltaic conversion efficiency (PCE). To mitigate the VOC loss in WBG PSCs, the defects in grains and grain boundaries are reduced as well as the energy-level alignment between perovskite layer and ETL, so as to improve the carrier collection efficiency, is optimized. Herein, potassium thiocyanate is introduced as an additive and 2-thiophenethylammonium bromide (TEABr) is used to passivate perovskite/C60 interface. The synergistic treatment reduces the defect density and prolongs the carrier lifetime, implying that nonradiative recombination is effectively suppressed. Meanwhile, the energy-level alignment of the perovskite and C60 is optimized, leading to the improvement of VOC. Finally, WBG PSCs with a bandgap of 1.68 eV achieve a VOC of 1.22 V (with a VOC loss of 0.46 V) and a PCE of 22.02%. [ABSTRACT FROM AUTHOR]

This paper presents a control solution for the problem of slung load transportation, with simultaneous damping of oscillations, using an underactuated autonomous quadrotor vehicle in the presence of external disturbances. The strategy put forward is divided into two parts: (i) resorting to an error definition that encompasses the pendular motion of the suspended load, a controller inspired in sliding‐mode theory is developed to compute a vectored thrust actuation that actively damps out the system's oscillations; (ii) two different approaches are illustrated for the stage of attitude tracking: one stemming from the conventional backstepping technique, which controls the vehicle in angular velocity commands; and another, also based on sliding‐mode theory, and built intrinsically in SO(3)$$ \mathsf{SO}(3) $$, that produces torque commands. The overall control scheme is proved to be robust and stable, with the load oscillations shown to be damped out in the process. Simulation and experimental results are presented in a trajectory tracking scenario to validate and assess the robustness and efficiency of the proposed technique. [ABSTRACT FROM AUTHOR]

In this article, we address the problem of ride height tracking control of the automotive active air suspension (AAS) system with uncertain sprung mass and external time‐varying disturbances. The proposed adaptive robust control approach guarantees that (i) the ride height converges towards, and stays within, an arbitrarily small neighborhood of the desired height, attaining uniform ultimate boundedness; (ii) the closed‐loop AAS system is (1) adaptive to uncertain sprung mass caused by the change of payload through the design of a projector‐based mass estimator; and, (2) robust to external time‐varying disturbance by developing a nonlinear disturbance observer. At last, co‐simulation (AMESim‐Matlab/Simulink) and experimental tests on a self‐fabricated quarter‐car test rig are conducted to demonstrate the effectiveness and performance of the proposed method. [ABSTRACT FROM AUTHOR]

The Cu‐modulated lead‐free double perovskite Cs2AgSbCl6 shows excellent photoelectric performances. Thus the distribution of Cu dopants inside Cs2AgSbCl6 and the influence induced by them are investigated thoroughly. The variation of charge distribution and then the electronic environment around the Cu dopant are simulated, which support the preferred formation of CuAg defect in Cs2AgSbCl6 with a nominal monovalent state. Compared with other Cu‐related defects, this configuration introduces the weakest tensile stress around the defects and the slightest distortion of the metal octahedron. Owing to the special CuAg defect, the electronic structures of Cs2AgSbCl6 system change, e.g., the bandgap reduces manifestly, ascribing to the predominant contribution from Cu‐3d orbitals to the band edges. With the increase of concentration of Cu dopants, the bandgap of Cs2AgSbCl6 decreases further in a monotonic but gentle way, originating from the extra interactions between the Cu‐3d orbitals. Therefore, the critical insight to understand the photoelectronic properties of Cs2AgSbCl6 modulated by the Cu dopants is provided. [ABSTRACT FROM AUTHOR]

Summary: Firefly algorithm (FA) is a new member of intelligent optimization algorithms. Several studies demonstrated that FA could successfully deal with several engineering and theoretical optimization problems. Nevertheless, there are some weak points in FA, such as parameter dependence and high computational complexity. To overcome the above issues, this paper proposes a modified FA based on neighborhood search (MFANS). In MFANS, there are three modifications. First, a modified attraction strategy is employed to reduce the complexity. Then, a neighborhood search method is used to search around the best neighborhood solutions. Third, the step parameter is dynamically adjusted. Performance of MFANS is compared with two improved FAs. Results show the effectiveness of MFANS. [ABSTRACT FROM AUTHOR]

Background: The coronavirus disease 2019 (COVID‐19) has been spreading all over the world since December 2019. However, medical information regarding the urogenital involvement in recovered COVID‐19 patients is limited or unknown. Objectives: To comprehensively evaluate urogenital involvement in recovered COVID‐19 patients. Materials and methods: Men aged between 20 years and 50 years who were diagnosed with SARS‐CoV‐2 infection and recovered when the study was conducted were enrolled in our study. Demographic and clinical characteristics, and history of hospitalization were collected and analyzed. Urine, expressed prostatic secretions (EPSs), and semen samples were collected for SARS‐CoV‐2 RNA detection. Semen quality and hormonal profiles were analyzed. Results: Among 74 male recovered COVID‐19 patients, 11 (14.9%) were asymptomatic, classified into mild type, and 31 (41.9%) were classified into moderate type. The remaining patients (32/74, 43.2%) had severe pneumonia. No critically ill recovered COVID‐19 patient was recruited in our cohort. The median interval between last positive pharyngeal swab RT‐PCR test and semen samples collection was 80 days (IQR, 64‐93). The median age was 31 years (IQR, 27‐36; range, 21‐49), and the median body mass index (BMI) was 24.40 (IQR, 22.55‐27.30). Forty‐five (61.6%) men were married, and 28 (38.4%) were unmarried. Fifty‐three (72.6%) patients denied cigarette smoking, 18 (24.7%) were active smokers, and 2 of them were past smokers. The majority of our participants (53/74, 72.6%) did not consume alcohol. Fever occurred in most of the patients (75.3%), and 63 of them had abnormal chest CT images. Only one patient complained of scrotal discomfort during the course of COVID‐19, which was ruled out orchitis by MRI (data not shown). A total of 205 samples were collected for SARS‐CoV‐2 detection (74 urine samples, 70 semen samples, and 61 EPS samples). However, viral nucleic acid was not detected in body fluids from the urogenital system. In terms of hormonal profiles, the levels of FSH, LH, testosterone, and estradiol were 5.20 [4.23] mIU/mL, 3.95 [1.63] mIU/mL, 3.65 [1.19] ng/mL, and 39.48 [12.51] pg/mL, respectively. And these values were within the normal limits. The overall semen quality of recovered COVID‐19 patients was above the lower reference limit released by the WHO. While compared with healthy control, sperm concentration, total sperm count, and total motility were significantly declined. In addition, different clinical types of COVID‐19 have no significant difference in semen parameters, but total sperm count showed a descending trend. Interestingly, subjects with a longer recovery time showed worse data for sperm quality. Small sample size and lacking semen parameters before the infection are the major limitations of our study. Discussion and conclusions: To the best of our knowledge, it is the largest cohort study with longest follow‐up for urogenital evaluation comprehensively so far. Direct urogenital involvement was not found in the recovered COVID‐19 male patients. SARS‐CoV‐2 RNA was undetectable in the urogenital secretions, and semen quality declined slightly, while hormonal profiles remained normal. Moreover, patients with a long time (≥90 days) since recovery had lower total sperm count. Great attention and further study should be conducted and follow‐up on the reproductive function in the following months. [ABSTRACT FROM AUTHOR]

Gamma‐ray (γ‐ray) irradiation was introduced into zeolite synthesis. The crystallization process of zeolite NaA, NaY, Silicalite‐1, and ZSM‐5 were greatly accelerated. The crystallization time of NaA zeolite was significantly decreased to 18 h under γ‐ray irradiation at 20 °C, while more than 102 h was needed for the conventional process. Unexpectedly, more mesopores were created during this process, and thus the adsorption capacity of CO2 increased by 6‐fold compared to the NaA prepared without γ‐ray irradiation. Solid experimental evidence and density function theory (DFT) calculations demonstrated that hydroxyl free radicals (OH*) generated by γ‐rays accelerated the crystallization of zeolite NaA. Besides NaA, mesoporous ZSM‐5 with MFI topology was also successfully synthesized under γ‐ray irradiation, which possessed excellent catalytic performance for methanol conversion, suggesting the universality of this new synthetic strategy for various zeolites. [ABSTRACT FROM AUTHOR]

Dysregulation of the epigenetic status of long noncoding RNAs (lncRNAs) has been linked to diverse human diseases including human cancers. However, the landscape of the whole‐genome methylation profile of lncRNAs and the precise roles of these lncRNAs remain elusive in renal cell carcinoma (RCC). We first examined lncRNA expression profiles in RCC tissues and corresponding adjacent normal tissues (NTs) to identify the lncRNA signature of RCC, then lncRNA Promoter Microarray was performed to depict the whole‐genome methylation profile of lncRNAs in RCC. Combined analysis of the lncRNAs expression profiles and lncRNAs Promoter Microarray identified a series of downregulated lncRNAs with hypermethylated promoter regions, including NR_023387. Quantitative real‐time polymerase chain reaction (RT‐PCR) implied that NR_023387 was significantly downregulated in RCC tissues and cell lines, and lower expression of NR_023387 was correlated with shorter overall survival. Methylation‐specific PCR, MassARRAY, and demethylation drug treatment indicated that hypermethylation in the NR_023387 promoter contributed to its silencing in RCC. Besides, HNF4A regulated the expression of NR_023387 via transcriptional activation. Functional experiments demonstrated NR_023387 exerted tumor‐suppressive roles in RCC via suppressing the proliferation, migration, invasion, tumor growth, and metastasis of RCC. Furthermore, we identified MGP as a putative downstream molecule of NR_023387, which promoted the epithelial–mesenchymal transition of RCC cells. Our study provides the first whole‐genome lncRNA methylation profile in RCC. Our combined analysis identifies a tumor‐suppressive and prognosis‐related lncRNA NR_023387, which is silenced in RCC via promoter hypermethylation and HNF4A deficiency, and may exert its tumor‐suppressive roles by downregulating the oncogenic MGP. [ABSTRACT FROM AUTHOR]

H‐type aluminosilicate zeolites are extensively used as solid‐acid catalysts and support materials in industrial catalysis. However, the conventional synthesis methods involving hydrothermal syntheses and ion‐exchange processes suffer from severe water pollution and toxic gas emissions. Herein, H‐type MFI zeolite catalysts with a unique stacked structure were directly synthesized in the presence of NH4F and with the help of zeolite confinement through a solvent‐free route without further ion‐exchange procedures. A range of ex situ and in situ characterization procedures were used to provide evidence of the simultaneous use of pre‐made ZSM‐5 and NH4F as a confined Al source and mineralizer, respectively. The confined zeolite framework of ZSM‐5 prevented the formation of AlFx species between NH4F and Al atoms, ensuring that the prepared samples had desirable acidic properties. Moreover, the resulting morphology could be controlled by using different silica substrates. The obtained H‐type MFI zeolites showed excellent catalytic performance in methanol‐to‐gasoline reactions owing to their unique structure and directly exposed acidic sites. The developed one‐pot strategy provides an alternative method for the facile synthesis of H‐type zeolites with defined morphology. [ABSTRACT FROM AUTHOR]

Background Information Dysregulated micro-RNAs have been reported in many human cancers, including renal cell carcinoma. Recent studies indicated that miR-490 is involved in tumour development and progression. However, the expression profile and function in renal cell carcinoma remains unknown. Results Herein, we showed that miR-490-5p was down-regulated in renal cell carcinoma tissues and cells compared with the adjacent normal tissues and normal cells. We also provided evidence that miR-490-5p acts as a tumour suppressor in renal carcinoma in a variety of in vitro and in vivo assays. Mechanistically, miR-490-5p was verified to directly bind to 3′ UTR of the PIK3CA mRNA and reduce the expression of PIK3CA at both mRNA and protein levels, which further inhibits phosphatidylinositol 3-kinase/Akt signalling pathway. We further showed that knockdown of PIK3CA can block the growth inhibitory effect of miR-490-5p, and over-expression of PIK3CA can reverse the inhibitory effect of miR-490-5p on renal cancer cell tumourigenicity. Conclusions Taken together, our results indicated for the first time that miR-490-5p functions as a tumour suppressor in renal carcinoma by targeting PIK3CA. Significance Our findings suggest that miR-490-5p may be a potential gene therapy target for the treatment of renal cell carcinoma. [ABSTRACT FROM AUTHOR]