Germanium selenide monolayer is promising in photoelectric applications for its natural p-type semiconductor and complicated band structures. Basic experimental investigations of few-to-monolayer germanium selenide are still absent; major scientific challenge is to develop of techniques for controllably thinned monolayers. In this study laser thinned monolayer germanium selenide on SiO 2 /Si substrates is demonstrated. A broad photoluminescence spectrum with eight continues peaks is observed from visible to infrared wavebands centered at ≈589, 655, 737, 830, 1034, 1178, 1314, and 1456 nm, respectively. First-principle calculations based on density functional theory illuminate the band structures of few-to-monolayer germanium selenide. Photoluminescence investigation combined with first-principle calculations indicates that the indirect to direct bandgap transition happens at few layers of N = 3. Current-voltage and photoresponse characteristics of monolayer based devices show 3.3 times the photosensitivity and much faster falling edges compared with those of the pristine nanosheet based devices. The present results provide useful insight into deep understanding of thickness dependent performances of germanium selenide monocrystalline.

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In recent years, with the increasingly popular and openness of Geoparks, Environmental safety has become a major concern for sustainable geo-tourism. It is therefore necessary to conduct an environmental safety performance evaluation for promoting geo-tourism development. In order to identify and figure out the factors influencing the tourists’ environmental safety perception, an index system was established based on six principles of Crime Prevention Through environment design (CPTED) theory. A Questionnaire was adopted for data collection, and the overall evaluation value and concrete index scores at all levels were obtained via the fuzzy comprehensive analysis and Importance-Performance analysis. Empirical results show that: (1) tourists’ perception of environmental safety performance in Shilin Park from high to low was: image and maintenance, Natural Surveillance, territoriality, Access control, Activity support and target hardening; (2) The sub-factors influencing tourists’ safety perception mostly include electronic monitoring device, Lighting system, Public safety management, Road layout, environmental sanitation; While attention should be paid on the following aspects including park service center, inter-personal surveillance, surrounding environment, unobstructed view, parking lot, Signpost, for they are considered as high-importance items with relatively poor performance. Based on the analysis, three optimization measures were proposed, including optimizing the layout and design of each space, strengthening the deterrent force of the park and maintaining a good environmental image. This research provides useful suggestions for Geopark decision-makers on determining the priority of Geopark spatial planning and management, as well as achieving the optimal allocation of resources to promote the sustainable development of Geopark.

PurposeIn recent years, understanding of the role of asparaginyl endopeptidase (AEP) in tumorigenesis has steadily increased. In this study, we investigated whether AEP expression correlates with sensitivity to chemotherapeutic drugs in gastric cancer and explored the mechanism.Patients and methodsAEP expression in the serum of patients’ peripheral blood was measured by enzyme-linked immunosorbent assay. Patient survival time was evaluated using univariate and multivariate analyses. Mass spectrometry and co-immunoprecipitation assays were utilized to discover proteins that interact with AEP. Gastric cancer cell lines were established, in which AEP was overexpressed or knocked out using lentiviral CRISPR. The proliferative abilities of these cell lines in response to chemotherapy agents were evaluated using the Cell Counting Kit-8 method. Gene expression changes in these lines were assessed by real-time polymerase chain reaction and Western blot.ResultsPatients with low expression of AEP were significantly more likely to have a good prognosis and experience complete response or partial response after treatment with docetaxel/S-1 regimen. Mass spectrum analysis showed that several proteins in the focal adhesion and mitogen-activated protein kinase signaling pathways interacted with AEP. IQGAP1 was confirmed to be one of the proteins interacting with AEP, and its protein level increased when AEP was knocked out. AEP knockout decreased resistance to microtubule inhibitors, including paclitaxel, docetaxel, and T-DM1. The expression levels of MDR1, p-EGFR, p-JNK, p-ERK, and p-Rac1/cdc42 were decreased in AEP knockout gastric cancer cell lines, and inhibitors of both JNK and ERK could block AEP-induced expression of MDR1.ConclusionAEP was not only a prognostic factor but also a predictive marker. AEP knockout could inhibit the activity of the EGFR/JNK/ERK signaling pathway and improve sensitivity to microtubule inhibitors through interacting with IQGAP1.

This paper provides a computable approach for the H ∞ control synthesis of nonlinear systems using the piecewise envelope method. Firstly, the computation method of piecewise envelope is presented such that the required piecewise linear differential inclusions (PWLDIs) can be obtained by solving a linear optimization problem. Then, we propose the H ∞ control design method for PWLDIs using piecewise Lyapunov function theory, all the synthesis conditions are formulated as the feasibility of linear matrix inequalities, hence computationally tractable. Because of the inclusion relationship, the H ∞ controllers designed for PWLDIs are also effective for original nonlinear systems. The validity of the proposed approach is tested by application to control a wheeled mobile robot.