Enhancement and Broadening of the Internal Electric Field of Hole-Transport-Layer-Free Perovskite Solar Cells by Quantum Dot Interface Modification.

Hole-transport-layer-free perovskite solar cells have attracted strong interest due to their simple structure and low cost, but charge recombination is serious. Built-in electric field engineering is an intrinsic driver to facilitate charge separation transport and improve the efficiency of photovoltaic devices. However, the enhancement of the built-in electric field strength is often accompanied by the narrowing of the space charge region, which becomes a key constraint to the performance improvement of the device. Here, we propose an effective regulation method, the component engineering of quantum dots, to enhance the strength of the built-in electric field and broaden the range of space charge. By using all inorganic CsPbBrxI3-x (x = 0, 1, 2, 3) quantum dot interface modification to passivate the defects of MAPbI3 perovskite films, the regulation law of quantum dot components on the work function of perovskite films was revealed, and the mechanism of their influence on the internal electric field intensity and space charge region distribution was further clarified, thereby fundamentally solving the serious problem of charge recombination. As directly observed by electron-beam-induced current (EBIC), the introduction of CsPbBr2I quantum dots can effectively enhance the interfacial electric field intensity, widening the space charge region from 160 to 430 nm. Moreover, the efficiency of the hole-free transport layer perovskite solar cells modified by CsPbBr2I quantum dots was also significantly enhanced by 1.5 times. This is an important guideline for electric field modulation and efficiency improvement within photovoltaic devices with other simplified structures.

Improved Fluorescence and Photoelectrical Properties of CsPbBr3 by Constructing Heterojunctions under Pressure.

All-inorganic cesium lead bromide quantum dots (CsPbBr3 -QD) compounds are potential candidates for optoelectronic devices, because of their excellent fluorescence luminescence and thermal stability. However, the many heterojunction interfaces and large band gap induce the low power conversion efficiency in the CsPbBr3 -QD heterojunction, limiting its practical applications. Hereby, in combination with the pressure regulation and TiO2 /CsPbBr3 -QD heterojunction, the interface interaction within the heterojunction can be enhanced and the band gap can be narrowed. The pressure-induced O─Ti─O bond softening and PbBr6 octahedron stiffening at the interface region significantly enhance the interface interactions that are favorable to the carrier transport. Compared with CsPbBr3 -QD, the atomic interaction between Pb and Br of TiO2 /CsPbBr3 -QD heterojunction can be dramatically enhanced at high pressures, leading to increased band gap narrowing rate by two times, which is useful to widen the absorption spectrum. The fluorescence intensity increases by two times. Compression increases the photocurrent and maintains it after the pressure is released, which is due to the enhanced interface interaction induced by the high pressure. The findings provide new opportunities to adjust the physical properties of perovskite heterogeneous structures, and have important applications in the field of new-generation photovoltaic devices.

Dynamic Evaluation of the Degradation Process of Vibration Performance for Machine Tool Spindle Bearings.

Real-time condition monitoring and fault diagnosis of spindle bearings are critical to the normal operation of the matching machine tool. In this work, considering the interference of random factors, the uncertainty of the vibration performance maintaining reliability (VPMR) is introduced for machine tool spindle bearings (MTSB). The maximum entropy method and Poisson counting principle are combined to solve the variation probability, so as to accurately characterize the degradation process of the optimal vibration performance state (OVPS) for MTSB. The dynamic mean uncertainty calculated using the least-squares method by polynomial fitting, fused into the grey bootstrap maximum entropy method, is utilized to evaluate the random fluctuation state of OVPS. Then, the VPMR is calculated, which is used to dynamically evaluate the failure degree of accuracy for MTSB. The results show that the maximum relative errors between the estimated true value and the actual value of the VPMR are 6.55% and 9.91%, and appropriate remedial measures should be taken before 6773 min and 5134 min for the MTSB in Case 1 and Case 2, respectively, so as to avoid serious safety accidents that are caused by the failure of OVPS.

OsGLYI3, a glyoxalase gene expressed in rice seed, contributes to seed longevity and salt stress tolerance.

The glyoxalase pathway plays a vital role in the chemical detoxification of methylglyoxal (MG) in biological systems. Our previous study suggested that OsGLYI3 may be effective in seed natural aging. In this study, the rice OsGLYI3 gene was cloned and characterized as specifically expressed in the seed. The accelerated aging (AA) treatment results indicated significant roles of OsGLYI3 in seed longevity and vigor, as the seeds of the transgenic lines with overexpressed and knocked-out OsGLYI3 exhibited higher and lower germination, respectively. The AA treatment also increased the superoxide dismutase (SOD) activity in the overexpressed transgenic seeds compared to the wild-type seeds yet lowered the SOD activity in the CRISPR/Cas9-derived transgenic rice lines. Rice OsGLYI3 was markedly upregulated in response to NaCl induced stress conditions. Compared to wild-type plants, overexpressed transgenic rice lines exhibited increased GLYI activity, decreased MG levels and improved salt stress tolerance, while CRISPR/Cas9 knockout transgenic rice lines showed decreased glyoxalase I activity, increased MG levels, and greater sensitivity to stress treatments with NaCl. Collectively, our results confirmed for the first time that OsGLYI3 is specifically expressed in rice seeds and contributes to seed longevity and salt stress tolerance.

Synthesis of 2-methoxybenzamide derivatives and evaluation of their hedgehog signaling pathway inhibition.

Aberrant hedgehog (Hh) signaling is implicated in the development of a variety of cancers. Smoothened (Smo) protein is a bottleneck in the Hh signal transduction. The regulation of the Hh signaling pathway to target the Smo receptor is a practical approach for development of anticancer agents. We report herein the design and synthesis of a series of 2-methoxybenzamide derivatives as Hh signaling pathway inhibitors. The pharmacological data demonstrated that compound 21 possessed potent Hh pathway inhibition with a nanomolar IC50 value, and it prevented Shh-induced Smo from entering the primary cilium. Furthermore, mutant Smo was effectively suppressed via compound 21. The in vitro antiproliferative activity of compound 21 against a drug-resistant cell line gave encouraging results.

Design and biological evaluation of phenyl imidazole analogs as hedgehog signaling pathway inhibitors.

The hedgehog (Hh) signaling pathway is involved in diverse aspects of cellular events. Aberrant activation of Hh signaling pathway drives oncogenic transformation for a wide range of cancers, and it is therefore a promising target in cancer therapy. In the principle of association and ring-opening, we designed and synthesized a series of Hh signaling pathway inhibitors with phenyl imidazole scaffold, which were biologically evaluated in Gli-Luc reporter assay. Compound 25 was identified to possess high potency with nanomolar IC50 , and moreover, it preserved the inhibition against wild-type and drug-resistant Smo-overexpressing cells. A molecular modeling study of compound 25 expounded its binding mode to Smo receptor, providing a basis for the further structural modification of phenyl imidazole analogs.

Comparative genomic and transcriptomic analyses of chemosensory genes in the citrus fruit fly Bactrocera (Tetradacus) minax.

The citrus fruit fly Bactrocera (Tetradacus) minax is a major and devastating agricultural pest in Asian subtropical countries. Previous studies have shown that B. minax interacts with plant hosts via the efficient chemosensory system. However, the molecular components of the B. minax chemosensory system have not been well characterized. Herein, we identified a total of 25 putative odorant-binding receptors (OBPs), 4 single-copy chemosensory proteins (CSPs) and 53 candidate odorant receptors (ORs) using a newly generated whole-genome dataset for B. minax. This study significantly extended the chemosensation-related gene profiles (particularly, OBPs and ORs) in six other tephritid species. Comparative transcriptome analysis of adult B. minax and Bactrocera dorsalis showed that there were 14 highly expressed OBPs (FPKM > 100) in B. dorsalis and 7 highly expressed ones in B. minax. The expression level of CSP3 gene and CSP4 gene was higher in B. dorsalis than that in B. minax. Comparative genomic and transcriptomic analyses of chemosensory genes in the citrus fruit fly B. minax provided new insights for preventive control of this agriculture important pest and closely related species.

Can the anatomy of abnormal flowers elucidate relationships of the androecial members in the ginger (Zingiberaceae)?

BACKGROUND: Interpretation of the floral structure of Zingiberaceae has long concentrated on the relationships of the androecial members. It suggested that labellum is composed of two structures rather than three or five, and glands are interpreted either as gynoecial part or as androecial members. METHODS: Serial sections were used to observe the vasculature of normal and two-staminate flowers in Alpinia intermedia 'shengzhen'. Floral diagrams were drawn to interpret the morphological category of the floral organs and the relationships of the androecial members. Androecial vascular bundles were associated with carpellary dorsal bundles (CDBs) and parietal bundles (PBs) in a Zingiberales phylogeny setting using ancestral state reconstruction. RESULTS: Anatomical observations demonstrate that the fertile stamen(s) incorporate parietal bundles both in normal and two-staminate flowers. The three appendages represent the three members of the outer whorl of the androecium, while the labellum represents the inner whorl of the androecium in the two-staminate flower. Reconstruction of the origin of the vascular system in the androecium suggests that the outer whorl of androecium receives its vascular supply from the CDBs, and the inner whorl of androecium receives from the PBs in both the basal banana group and the more derived ginger clade. CONCLUSIONS: The present study adds to a growing body of literature suggesting that the anatomy of abnormal flowers may not provide enough evidence for elucidating the relationships of the androecial members, and help us to better understand how the vascular system is constructed during the androecial petaloidy evolution.

Transcriptome sequencing identifies key pathways and genes involved in gastric adenocarcinoma.

The present study aimed to investigate the key pathways and genes associated with gastric adenocarcinoma via transcriptome sequencing. Five pairs of gastric adenocarcinoma tissue and normal tumor­adjacent tissue were harvested. After sequencing, raw data were processed and differentially expressed genes (DEGs) between tumor and control groups were screened, followed by functional enrichment analysis and gene clustering analysis. The effect of DEGs on patient prognosis was analyzed on the basis of the survival data from gastric adenocarcinoma patients in The Cancer Genome Atlas database. Several genes were validated through reverse transcription­quantitative polymerase chain reaction. In total, 1,477 upregulated and 282 downregulated DEGs were screened in tumor groups. These genes were segregated into four clusters. Genes in cluster 1 were significantly involved in metabolism of xenobiotics by cytochrome P450, genes in cluster 2 were majorly involved in apoptosis, tight junction formation, and platelet activation, genes in cluster 3 were primarily enriched in the p53 signaling pathway and genes in cluster 4 were significantly enriched in the insulin resistance pathway. Furthermore, 15 DEGs significantly influenced prognosis, including F2R, CTHRC1, and RASGRP3. The expression levels of CYP2B6, MAPK13, CTHRC, RASGRP3 and PYGM were consistent with our analysis results. In conclusion, pathways for metabolism of xenobiotics via cytochrome P450, apoptosis, tight junction formation, platelet activation, and insulin resistance may serve important roles in the progression of gastric adenocarcinoma. Notably, CTHRC1 and RASGRP3 may serve as key prognostic markers.

The expression levels of Notch-related signaling molecules in pulmonary microvascular endothelial cells in bleomycin-induced rat pulmonary fibrosis.

Previous studies have suggested that the Notch signaling pathway plays a very important role in the proliferation and differentiation of pulmonary microvascular endothelial cells (PMVECs). Therefore, we aimed to investigate the expression level of Notch-related signaling molecules in PMVECs in bleomycin (BLM)-induced rat pulmonary fibrosis. Immunohistochemistry, immunofluorescence, Western blotting, and real-time PCR were used to analyze the differences in protein and mRNA expression levels of Notch-related signaling molecules, i.e. Notch1, Jagged1, Delta-like ligand 4 (Dll4), and hairy and enhancer of split homolog 1 (Hes1), between a control group treated with intratracheal instillation of saline and a study group treated with intratracheal instillation of BLM solution. Expression levels of the receptor Notch1 and one of its ligands, Jagged1, were upregulated, while the expression levels of the ligand Dll4 and the target molecule of the Notch signaling pathway, Hes1, were downregulated. The differences in protein and mRNA expression levels between the control and study groups were significant (p<0.001). The Jagged1/Notch1 signaling pathway is activated in the pathogenesis of BLM-induced rat pulmonary fibrosis, while the Dll4/Notch1 signaling pathway is inhibited, which inhibits the suppressive effect of Dll4/Notch1 signaling on PMVEC overproliferation, further causing PMVEC dysfunction in cell sprouting and maturation as well as abnormal differentiation of the cell phenotype. Conversely, the down-expression of Hes1 indicates that the Jagged1/Notch1 signaling pathway could be a non-canonical Notch signaling pathway independent of Hes1 activation, which differs from the canonical Dll4/Notch1 signaling pathway.

Pulmonary microvascular endothelial cells from bleomycin-induced rats promote the transformation and collagen synthesis of fibroblasts.

Accumulation and activation of myofibroblasts are the hallmark of progressive pulmonary fibrosis, and the resident fibroblasts are the major source of myofibroblasts. However, the key factors involved in the transformation of fibroblasts are unknown. Pulmonary microvascular endothelial cells (PMVECs), major effector cells against pathogenesis in early stages of the disease, can secrete cytokines to induce the differentiation of mesenchymal cells. We speculated that PMVECs could secrete pro-fibrotic cytokines and promote the transformation of fibroblasts into myofibroblasts. Accordingly, we established a co-culture system with PMVECs and fibroblasts to examine the specific transformation and collagen synthesis of the co-cultured fibroblasts by FACS and Western blot, prior to and after treatment with neutralizing antibodies against transforming growth factor-beta1 (TGF-ß1) and connective tissue growth factor (CTGF). We also analyzed expression of TGF-ß1 and CTGF in PMVECs. The synthesis and secretion of TGF-ß1 and CTGF protein were up-regulated in PMVECs isolated from bleomycin (BLM)-treated rats, most prominently at 7 days post-instillation. We showed that the PMVECs isolated from BLM-induced rats could induce the transformation of normal fibroblasts and their secretion of collagen I, which was inhibited by both neutralizing anti-TGF-ß1 and anti-CTGF antibodies. Therefore, up-regulation of TGF-ß1 and CTGF in PMVECs plays an important role in activation, transformation, and collagen synthesis of fibroblasts; in particular, these effects in PMVECs are likely to be the key factors for activation and stimulation of static fibroblasts in lung interstitium in early stages of pulmonary fibrosis disease.

[Dynamics of Sophora davidii population in a hilly region closed for thirty years in Loess Plateau].

Taking wild grass ground as the reference, this paper studied the dynamics of Sophora davidii population on the sunny, semi-sunny and semi-shady slopes of hilly region in Loess Plateau after 30 years closed for reforestation, and analyzed the age structure, spatial distribution pattern, life table, and survival curve of the population. The results showed that S. dvidii population in the region belonged to progressive type, with more young and less old individuals. Among the three habits, semi-sunny slope had the highest population density. The survival curve of S. dvidii population was approached to Deevey 11 type. The population pattern was of clustered distribution, with the aggregating intensity increased with age. Water and light were the main environmental factors affecting the recovery and development of S. davidii community. The better recovery of S. davidii population suggested that the measures of closing the land for reforestation were efficient.