van der Waals (vdW) epitaxy offers a promising strategy without lattice and processing constraints to prepare atomically clean and electronically sharp interfaces for fundamental studies and ...electronic device demonstrations. Herein, PbI
was thermally deposited at high-vacuum conditions onto CVD-grown monolayer MoS
flakes in a vdW epitaxial manner to form 3D-2D heterojunctions, which are promising for vdW epitaxial growth of perovskite films. X-ray diffraction, X-ray photoemission spectroscopy, Raman, and atomic force microscopy measurements reveal the structural properties of the high-quality heterojunctions. Photoluminescence (PL) measurements reveal that the PL emissions from the bottom MoS
flakes are greatly quenched compared to their as-grown counterparts, which can be ascribed to the band alignment-induced distinct interfacial charge-transfer behaviors. Strong interlayer excitons can be detected at the PbI
/MoS
interface, indicating an effective type II band alignment, which can be further confirmed by ultraviolet photoemission spectroscopy measurements. The results provide a new material platform for the application of the vdW heterojunctions in electronic and optoelectronic devices.
We report a search for light dark matter produced through the cascading decay of η mesons, which are created as a result of inelastic collisions between cosmic rays and Earth's atmosphere. We ...introduce a new and general framework, publicly accessible, designed to address boosted dark matter specifically, with which a full and dedicated simulation including both elastic and quasielastic processes of Earth attenuation effect on the dark matter particles arriving at the detector is performed. In the PandaX-4T commissioning data of 0.63 tonne·year exposure, no significant excess over background is observed. The first constraints on the interaction between light dark matter generated in the atmosphere and nucleus through a light scalar mediator are obtained. The lowest excluded cross section is set at 5.9×10^{-37} cm^{2} for a dark matter mass of 0.1 MeV/c^{2} and mediator mass of 300 MeV/c^{2}. The lowest upper limit of η to the dark matter decay branching ratio is 1.6×10^{-7}.
Tomato fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici (Fol) is a highly destructive disease, resulting in severe economic losses of global tomato production annually. An eco-friendly ...alternative to chemical fungicide using biological control agents (BCAs) is urgently needed. Here, Bacillus siamensis QN
MO-1 was isolated from Noli fruit and had a strong antagonistic activity against Fol in vitro and in vivo. Strain QN
MO-1 also exhibited a broad-spectrum antifungal activity against the selected 14 phytopathogenic fungi. The crude protein produced by strain QN
MO-1 could inhibit the spore germination of Fol and destroy the spore structure. It was closely related with the generation of chitinase and β-1,3-glucanase secreted by strain QN
MO-1. In a pot experiment, the application of B. siamensis QN
MO-1 effectively alleviated the yellowing and wilting symptoms of tomato plants. The disease index and incidence rate were decreased by 72.72% and 80.96%, respectively. The rhizospheric soil in tomato plants owed a high abundance of microbial community. Moreover, strain QN
MO-1 also enhanced the plant growth and improved the fruit quality of tomato. Therefore, B. siamensis QN
MO-1 will be explored as a potential biocontrol agent and biofertilizer.
Background:Although methionine (Met), the first-limiting dietary amino acid, has crucial roles in growth and regulation of lipid metabolism in ducks, mechanisms underlying are not well understood. ...Therefore, the objective was to use dietary Met deficiency to investigate the involvement of Met in lipid metabolism and fat accumulation of Pekin ducks. Methods:A total of 150 male Pekin ducks (15-d-old, 558.5 ± 4.4 g) were allocated into 5 groups (6 replicates with 5 birds each) and fed corn and soybean meal-based diets containing 0.28％, 0.35％, 0.43％, 0.50％, and 0.58％Met, respectively, for 4 weeks. Met-deficient (Met-D, 0.28％Met) and Met-adequate (Met-A, 0.43％Met) groups were selected for subsequent molecular studies. Serum, liver, and abdominal fat samples were collected to assess the genes and proteins involved in lipid metabolism of Pekin ducks and hepatocytes were cultured in vivo for verification. Results:Dietary Met deficiency caused growth depression and excess fat deposition that were ameliorated by feeding diets with adequate Met. Serum triglyceride and non-esterified fatty acid concentrations increased (P< 0.05), whereas serum concentrations of total cholesterol, low density lipoprotein cholesterol, total protein, and albumin decreased (P<0.05) in Met-D ducks compared to those in Met-A ducks. Based on hepatic proteomics analyses, dietary Met deficiency suppressed expression of key proteins related to fatty acid transport, fatty acid oxidation, tricarboxylic acid cycle, glycolysis/gluconeogenesis, ketogenesis, and electron transport chain;selected key proteins had similar expression patterns verified by qRT-PCR and Western blotting, which indicated these processes were likely impaired. In vitro verification with hepatocyte models confirmed albumin expression was diminished by Met deficiency. Additionally, in abdominal fat, dietary Met deficiency increased adipocyte diameter and area (P<0.05), and down-regulated (P<0.05) of lipolytic genes and proteins, suggesting Met deficiency may suppress lipolysis in adipocyte. Conclusion:Taken together, these data demonstrated that dietary Met deficiency in Pekin ducks resulted in stunted growth and excess fat deposition, which may be related to suppression of fatty acids transportation and hepatic catabolism.
With the widespread application of Internet of Things (IoT) systems in various fields such as healthcare, transportation, and industrial production, the data transmission efficiency and network ...resource occupancy of system managed devices and various sensors have become urgent issues to be solved. This paper introduces edge computing to solve these problems, and verifies the effect of edge computing in IoT system through comparative experiments. The study found that edge computing significantly improved the information processing speed of the IoT system. The average delay time of the experimental group was 3.03 milliseconds, while the control group without edge computing was 4.03 milliseconds. This shows that edge computing can significantly optimize the data processing and analysis capability and efficiency of IoT system.
NH
, SO
, NO
and the inorganic ions of PM
in winter 2009, 2014 and 2016 were examined to investigate the change in NH
and aerosol chemistry in Beijing, China. NH
concentrations showed an increase by ...59% on average, in contrast to the decrease of SO
by 63% from winter 2009 to 2016. The mean mass ratio of NH
/NH
was 0.83 ± 0.12 in 2016, which is higher than those obtained in 2009 and 2014, implying more NH
remaining as free NH
in 2016 winter. Our findings suggest that vehicles exhaust emissions are an important NH
source in urban central atmosphere of Beijing in winter. Despite the observed NO
presenting declining trends from 2014 to 2016, nitrate concentrations even exhibited a significant increasing trend, which may be largely attributable to high NH
levels. An in-depth analysis of measured NH
and aerosol species in a heavy pollution episode in December 2016, combined with the acidity predicted by ISORROPIA II model demonstrated abundant NH
most of the time in air, where NH
is not only a precursor for NH
but also effect the neutralization of SO
and NO
in PM
. With high RH and low photochemical activity, elevated NO
concentration was attributed to an enhanced heterogeneous conversion of NO
to HNO
to form NH
NO
in pollution transport stage. The decrease in NO
from high level and the increase in NH
, with peaks of SO
occurring were observed in pollution cumulative stage. The aqueous-phase oxidation of SO
by NO
to sulfate might play an important role with high pH values. Our results suggested that the simultaneous control of NH
emissions in conjunction with SO
and NO
emissions would be more effective in reducing particulate matter PM
formation.
