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Low-frequency (LF) noise measurements are compared for Schottky-gate AlGaN/GaN heterostructure planar and fin field-effect transistors (FinFETs) as functions of gate voltage and measuring temperature. The noise of each device type is consistent with a carrier number fluctuation model. Similar effective defect-energy Eo distributions are derived for each of the two device architectures from measurements of excess drain-voltage noise-power spectral density vs temperature from 80 to 380 K. Defect- and/or impurity-related peaks are observed in the inferred energy distributions for Eo < 0.2 eV, Eo ≈ 0.45 eV, and Eo > 0.6 eV. Significant contributions to the LF noise are inferred for nitrogen vacancies and ON and FeGa impurity complexes. Ga dangling bonds at fin interfaces with gate metal are likely candidates for enhanced noise observed in FinFETs, relative to planar devices. Reducing the concentrations of these defects and impurity complexes should reduce the LF noise and enhance the performance, reliability, and radiation tolerance of GaN-based high electron mobility transistors. [ABSTRACT FROM AUTHOR]

Current–voltage characteristics and low-frequency (LF) noise of industrial-quality AlGaAs/InGaAs/GaAs pseudomorphic high-electron-mobility transistors are evaluated as a function of bias stress and temperature. A small positive shift of threshold voltage Vth and negligible degradation in peak transconductance GM are observed under ON-state bias conditions at elevated temperatures. The Vth measurements suggest activation of an acceptor-like defect or impurity center. The GM measurements demonstrate that newly activated defects are not located close enough to the two-dimensional electron gas to scatter carriers strongly. First-principles calculations and comparisons with previous work suggest that OAs impurity centers, other oxygen-related defects, isolated AsGa antisites, and dopant-based DX centers may contribute significantly to low-frequency (LF) noise in as-processed devices. LF noise is relatively unaffected by voltage stress at elevated temperatures, consistent with the small changes in Vth and peak GM. [ABSTRACT FROM AUTHOR]

Change-point analysis of time-series data plays a vital role in various fields of earth sciences under changing environments. Most of the analysis approaches were usually designed to detect the change-point in the level of time-series mean. In this study, we aimed to propose a non-parametric approach to detect the change-point of different parameters of time-series data. In this approach, the Boot- strap method, coupling with Kernel density estimation, was first used to estimate the probability distribution function (pdf) of a parameter before and after any potential change-points. Second, the Ar-index based on the uncross area of the two pdfs was designed to quantify the difference of the parameter before and after each potential change-point. Finally, the potential change-point owning the largest Ar-index value was determined as the locations of the change-point of the parameter. The hydrological extreme series from four stations in the Hanjiang basin were used to demonstrate this approach. The Pettitt test method commonly used in hydrology was employed as a comparison to indirectly analyze the reliability of the proposed approach. The results show that change-point detected by the proposed approach in the four stations are identified with those detected by the Pettitt approach in the level of time-series mean. But in comparison with the Pettitt test, the proposed approach can provide more detection information for other parameters, such as coefficient of variation (Cv) and coefficient of skewness (Cs) of the series. The results also show that the degree of change in the series mean is greater than its Cv and Cs, while the degree of change in series Cv is greater than its Cs. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To summarize the current practice and potential strategy in diagnosing coronavirus disease 2019 (COVID-19). MATERIALS AND METHODS: PubMed, Web of Science were systematically searched using terms including "COVID-19", "SARS-CoV-2" and "2019-nCoV". After removing duplicates, we then identified articles, letters and commentaries regarding diagnosing COVID-19. RESULTS: Here we summarized relatively mature diagnostic methods like nuclear acid test and computed tomography. Besides, new aspects regarding these detection methods like suitable specimens for nuclear acid test, possible use of 18F-FDG PET/CT were also reported. Especially, we also presented several novel techniques for diagnosing COVID-19 like lung ultrasound. CONCLUSIONS: Chinese Clinical Guidance for COVID-19 Pneumonia Diagnosis and Treatment (7th edition) by National Health Commission is recommended to follow as it provides detailed diagnostic procedures using currently available tools. We suggest clinicians further explore the saliva's utility as a specimen for nuclear acid test and the use of lung ultrasound. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Lung cancer is the main burden on human health, with high mortality and poor prognosis. The involvement of long non-coding RNAs (lncRNAs) in the development of cancer has attracted wide attention. This study aimed to investigate the role and novel mechanisms of lncRNA nicotinamide nucleotide transhydrogenase antisense RNA 1 (NNTAS1) in the progression of lung cancer. MATERIALS AND METHODS: Quantitative Real Time-Polymerase Chain Reaction (qRTPCR) was performed to detect the expression of NNT-AS1, microRNA-3666 (miR-3666), and E2F transcription factor 2 (E2F2). 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay was used to analyze cell proliferation. Flow cytometry was carried out to investigate cell apoptosis. Transwell assay was conducted to observe cell invasion. The interaction between miR-3666 and NNT-AS1 or E2F2 was predicted by bioinformatics tool starBase v2.0 and verified by Dual-Luciferase reporter assay. The protein level of E2F2 was quantified by Western blot. RESULTS: NNT-AS1 and E2F2 were upregulated, but miR-3666 was downregulated in lung cancer tissues and cells. NNT-AS1 knockdown attenuated proliferation and invasion but enhanced apoptosis of lung cancer cells, while miR-3666 inhibition reversed these effects. It was confirmed that miR-3666 was a target of NNT-AS1 and it directly interacted with E2F2. The inhibitory proliferation and invasion, and acceleratory apoptosis of lung cancer cells, caused by miR-3666 enrichment, were overturned by E2F2 overexpression. Furthermore, E2F2 was regulated by NNT-AS1 through miR-3666. CONCLUSIONS: NNT-AS1 participated in the progression of lung cancer through NNT-AS1/miR-3666/E2F2 regulatory axis at least in part. Our study supplied a promising strategy for the treatment of lung cancer. [ABSTRACT FROM AUTHOR]

To improve the sintering performance of doped barium zirconate, (ZrO2)0.92(Y2O3)0.08 (YSZ) was added and BaZr0.8Y0.2O3-δ (BZY)-x%YSZ (x = 20, 30 and 50% by weight) composite ceramics were prepared by mechanical ball milling combined with high-temperature sintering in air. The crystalline structure, chemical composition, microstructure and electrical properties of the composite electrolytes were characterized by XRD, SEM, TEM, EDS and EIS, respectively. The composite electrolytes only consist of BZY and YSZ phases, and there are no precipitates in BZY/YSZ grain boundaries according to the HR-TEM analysis. YSZ addition can improve the sintering properties of the composite electrolytes. When the composite ceramics with YSZ content of 50 wt% are sintered at 1450 °C for 6 h, the relative density and linear shrinkage are optimal. At 700 °C, the electrical conductivity of BZY-50%YSZ ceramic reaches 1.95 × 10−4 S/cm and 1.67 × 10−4 S/cm in the dry air and moist air, respectively. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To investigate the expression and function of up-regulator of gene-4 (URG4) in nasopharyngeal carcinoma (NPC). PATIENTS AND METHODS: Fresh NPC tumor tissue samples with paired adjacent normal nasopharyngeal tissues samples of 9 NPC patients were collected from NPC curative resection surgery. NPC cell lines (CNE1, CNE2 and HONE1) were cultured. Lentivirus-mediated URG4-specific short hairpin RNA (shRNA) stable transfection was done. The effect of URG4 on CNE4 and HONE1 cells viability was determined via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT). The plate-colony-formation assay was performed. Apoptosis analysis was done by flow cytometry. The expression levels of protein and RNA were detected by Western blotting and quantitative polymerase chain reaction (qPCR). RESULTS: We determined the expression of URG4/URGCP in NPC tissues and cell lines using qPCR analysis and found it was significantly upregulated in NPC. After that, stable URG4-silencing NPC cells were constructed by transfection with lentivirus-mediated shRNA. Functionally analyses indicated that knockdown of URG4 significantly impaired cell viability and colony formation ability, as confirmed by MTT and colony formation assays. Furthermore, URG4-silencing NPC cells showed more cells in the stage of early and late apoptosis compared with controls by flow cytometry assay. Western blot analysis further confirmed that knockdown of URG4 enhanced the expression of cleaved caspase-3, cleaved PARP and Bax, while decreased the expression of Bcl-2 and survivin. CONCLUSIONS: URG4/URGCP might play an essential role in NPC cell growth and proliferation and its silencing might be as a potential therapeutic target for NPC. [ABSTRACT FROM AUTHOR]