Two-dimensional layered material photodetectors: what could be the upcoming downstream applications beyond prototype devices?

With distinctive advantages spanning excellent flexibility, rich physical properties, strong electrostatic tunability, dangling-bond-free surface, and ease of integration, 2D layered materials (2DLMs) have demonstrated tremendous potential for photodetection. However, to date, most of the research enthusiasm has been merely focused on developing novel prototype devices. In the past few years, researchers have also been devoted to developing various downstream applications based on 2DLM photodetectors to contribute to promoting them from fundamental research to practical commercialization, and extensive accomplishments have been realized. In spite of the remarkable advancements, these fascinating research findings are relatively scattered. To date, there is still a lack of a systematic and profound summarization regarding this fast-evolving domain. This is not beneficial to researchers, especially researchers just entering this research field, who want to have a quick, timely, and comprehensive inspection of this fascinating domain. To address this issue, in this review, the emerging downstream applications of 2DLM photodetectors in extensive fields, including imaging, health monitoring, target tracking, optoelectronic logic operation, ultraviolet monitoring, optical communications, automatic driving, and acoustic signal detection, have been systematically summarized, with the focus on the underlying working mechanisms. At the end, the ongoing challenges of this rapidly progressing domain are identified, and the potential schemes to address them are envisioned, which aim at navigating the future exploration as well as fully exerting the pivotal roles of 2DLMs towards the practical optoelectronic industry.

RBFNN-Based Singularity-Free Terminal Sliding Mode Control for Uncertain Quadrotor UAVs.

In this article, a singularity-free terminal sliding mode (SFTSM) control scheme based on the radial basis function neural network (RBFNN) is proposed for the quadrotor unmanned aerial vehicles (QUAVs) under the presence of inertia uncertainties and external disturbances. Firstly, a singularity-free terminal sliding mode surface (SFTSMS) is constructed to achieve the finite-time convergence without any piecewise continuous function. Then, the adaptive finite-time control is designed with an auxiliary function to avoid the singularity in the error-related inverse matrix. Moreover, the RBFNN and extended state observer (ESO) are introduced to estimate the unknown disturbances, respectively, such that prior knowledge on system model uncertainties is not required for designing attitude controllers. Finally, the attitude and angular velocity errors are finite-time uniformly ultimately bounded (FTUUB), and numerical simulations illustrated the satisfactory performance of the designed control scheme.

[Effect of oral administration of icariin on periodontitis associated alveolar bone resorption in an osteoporosis mouse model].

PURPOSE: To study the effect of oral administration of icariin (ICA) on periodontitis associated alveolar bone resorption in an osteoporosis mouse model. METHODS: Three-month old, female C57BL/6J mice were randomly divided into 3 groups: normal group (SHAM), ovariectomy + oral smearing of Porphyromonas gingivalis (Pg) + icariin group (OVX+Pg+ICA), ovariectomy+ Pg group (OVX+Pg). On the second week, the mice underwent ovariectomy to induce osteoporosis. On the fourth week, the mice were treated with Pg by oral smearing for 1 week, 1 time/day. The samples were harvested on the 12th week: the left mandibles were harvested to make the sections and histological staining, to analyze the differences of bone resorption areas among the three groups; the right mandibles were harvested for methylene blue staining, to analyze the differences of bone resorption depth among the three groups. Protein from the periodontal tissues were extracted to analyze the differences of osteoblastic related protein expression level among the three groups. SPSS 16.0 software package was used for statistical analysis. RESULTS: Histological analysis of murine femurs and periodontal tissues demonstrated that the model of periodontitis in osteoporosis mice was successfully created in this study. Quantification of the histological staining showed that compared with OVX+Pg group, icariin treatment decreased the depth of CEJ-ABC and the areas of alveolar bone resorption(P＜0.05); Western blot results showed icariin treatment could significantly increase the protein expression level of Runx2, OSX, OCN and OPN in periodontal tissues(P＜0.05). CONCLUSIONS: Icariin treatment can effectively prevent both bone loss in osteoporosis and alveolar bone resorption induced by periodontitis.

A monoclonal antibody that tracks endospore formation in the microsporidium Nosema bombycis.

Nosema bombycis, the first identified microsporidium, is a destructive pathogen of the silkworm Bombyx mori and causes severe worldwide economic losses in sericulture. Major microsporidian structural proteins, such as the spore wall protein (SWP), are known to be involved in host invasion. In this study, the reactivity of the monoclonal antibody 2B10 was tested against an endospore protein of N. bombycis with a molecular weight size at 50-kDa, using Western blotting. The antigen was purified after immunoprecipitation and was further identified as EOB13320 according to MALDI-TOF MS assay. We found that EOB13320 locates to the surface of the different developmental stages of the parasite, mostly the sporoblast stage and the mature spore after immunoelectron microscopy examination. EOB13320 was also widely distributed in the developing endospore, especially at the sporoblast stage. This endospore protein also accumulated in the cytoplasm of both the merogony and sporoblast stages. These results imply that EOB13320 detected by monoclonal antibody 2B10 is expressed throughout the life cycle of the parasite, notably during the stage when the endospore is formed, and that this protein is important for spore-coat formation and parasite maintenance. Our study could be instrumental in the understanding of spore wall formation and will help to gain greater insight into the biology of this parasite.

Protective effect of 7-difluoromethoxy-5,4'-Di-hydroxyl isoflavone against the damage induced by glutamate in PC12 cells.

7-difluoromethoxy-5,4'-Di-hydroxyl isoflavone (dFGEN), prepared by the difluoromethylation of genistein, is an active chemical entity. In this study, our main purpose was to investigate whether dFGEN had an effect on glutamate-induced apoptosis in cultured PC12 cells. The PC12 cells were treated with different glutamate concentrations for 24 h in vitro. The PC12 cells impaired by glutamate were used as the cell model of excitability. Cells were incubated for 30 min with genistein, dFGEN, vitamin E, and exposed to 10 mM glutamate for 24 h. Cell morphology was observed by light microscopy. The growth and proliferation of PC12 cells were detected by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Cell apoptosis was determined by flow cytome-try (FCM) with propidium iodide (PI) staining. The activity of lactate dehydrogenase (LDH), superoxide dismutase (SOD) and the content of malondialdelyde (MDA) were measured by kits, respectively. Acridine orange (AO) staining was used to detect characteristics of cell apoptosis. When PC12 cells were incubated with glutamate for 24 h, cells appeared to have significant changes in shape. The cellular viability was reduced and the apoptotic rate was increased. The levels of LDH and the content of MDA were increased. The activity of SOD was decreased. After PC12 cells were pretreated with dFGEN, dFGEN significantly improved cell morphology, cell growth and proliferation, suppressed apoptosis of cells, reduced the release of LDH, improving SOD activity and decreased MDA content in a concentration-dependent manner. AO staining displayed that apoptosis was decreased. These results suggested that dFGEN has a protective effect against glutamate-induced damage in PC12 cells. dFGEN seemed to have a better protective effect than the lead compound genistein in a concentration-dependent manner. The mechanism of protective effect of dFGEN may be mainly related to its antioxidative activity.

Drug screening study using glioma stem-like cells.

Glioma is one of the most common malignant tumors affecting the central nervous system. We screened active drugs from 12 classes to provide experimental data for the study of human glioma. Serum-free suspension clone formation was used to induce the formation of glioma stem­like cells (GSLCs) from U251 cells. We screened active drugs from 12 classes and observed their effects on the number of tumor balls. The results revealed that serum­free suspension clone formation successfully induced the formation of GSLCs. Six active drugs [curcumin, chrysin, apigenin, luteolin, casticin and 8-bromo-7-methoxychrysin (BrMChR)] were identified by MTT assay. The drugs that affected the number of tumor balls were curcumin, luteolin, casticin and BrMChR (all P<0.05). The GSLCs were obtained by serum­free clone suspension formation and exhibited the features of cancer stem cells.