van der Waals (vdW) p–n heterojunctions formed by two-dimensional nanomaterials exhibit many physical properties and deliver functionalities to enable future electronic and optoelectronic devices. In ...this report, we demonstrate a tunable and high-performance anti-ambipolar transistor based on MoTe2/MoS2 heterojunction through in situ photoinduced doping. The device demonstrates a high on/off ratio of 105 with a large on-state current of several micro-amps. The peak position of the drain–source current in the transfer curve can be adjusted through the doping level across a large dynamic range. In addition, we have fabricated a tunable multivalue inverter based on the heterojunction that demonstrates precise control over its output logic states and window of midlogic through source–drain bias adjustment. The heterojunction also exhibits excellent photodetection and photovoltaic performances. Dynamic and precise modulation of the anti-ambipolar transport properties may inspire functional devices and applications of two-dimensional nanomaterials and their heterostructures of various kinds.
Plant type 2Fe-2S ferredoxins function primarily as electron transfer proteins in photosynthesis. Studying the unfolding–folding of ferredoxins in vitro is challenging, because the unfolding of ...ferredoxin is often irreversible due to the loss or disintegration of the iron–sulfur cluster. Additionally, the in vivo folding of holo-ferredoxin requires ferredoxin biogenesis proteins. Here, we employed atomic force microscopy-based single-molecule force microscopy and protein engineering techniques to directly study the mechanical unfolding and refolding of a plant type 2Fe-2S ferredoxin from cyanobacteria Anabaena. Our results indicate that upon stretching, ferredoxin unfolds in a three-state mechanism. The first step is the unfolding of the protein sequence that is outside and not sequestered by the 2Fe-2S center, and the second one relates to the force-induced rupture of the 2Fe-2S metal center and subsequent unraveling of the protein structure shielded by the 2Fe-2S center. During repeated stretching and relaxation of a single polyprotein, we observed that the completely unfolded ferredoxin can refold to its native holo-form with a fully reconstituted 2Fe-2S center. These results demonstrate that the unfolding–refolding of individual ferredoxin is reversible at the single-molecule level, enabling new avenues of studying both folding–unfolding mechanisms, as well as the reactivity of the metal center of metalloproteins in vitro.
Ivermectin has powerful antitumor effects, including the inhibition of proliferation, metastasis, and angiogenic activity, in a variety of cancer cells. This may be related to the regulation of ...multiple signaling pathways by ivermectin through PAK1 kinase. On the other hand, ivermectin promotes programmed cancer cell death, including apoptosis, autophagy and pyroptosis. Ivermectin induces apoptosis and autophagy is mutually regulated. Interestingly, ivermectin can also inhibit tumor stem cells and reverse multidrug resistance and exerts the optimal effect when used in combination with other chemotherapy drugs.
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•Ivermectin effectively suppresses the proliferation and metastasis of cancer cells and promotes cancer cell death at doses that are nontoxic to normal cells.•Ivermectin shows excellent efficacy against conventional chemotherapy drug-resistant cancer cells and reverses multidrug resistance.•Ivermectin combined with other chemotherapy drugs or targeted drugs has powerful effects on cancer.•The structure of crosstalk centered on PAK1 kinase reveals the mechanism by which ivermectin regulates multiple signaling pathways.•Ivermectin has been used to treat parasitic diseases in humans for many years and can quickly enter clinical trials for the treatment of tumors.
Ivermectin is a macrolide antiparasitic drug with a 16-membered ring that is widely used for the treatment of many parasitic diseases such as river blindness, elephantiasis and scabies. Satoshi ōmura and William C. Campbell won the 2015 Nobel Prize in Physiology or Medicine for the discovery of the excellent efficacy of ivermectin against parasitic diseases. Recently, ivermectin has been reported to inhibit the proliferation of several tumor cells by regulating multiple signaling pathways. This suggests that ivermectin may be an anticancer drug with great potential. Here, we reviewed the related mechanisms by which ivermectin inhibited the development of different cancers and promoted programmed cell death and discussed the prospects for the clinical application of ivermectin as an anticancer drug for neoplasm therapy.
X-ray micro-computed tomography (CT) is an important tool for high-resolution three-dimensional imaging. But one limitation of micro-CT is the compromise between resolution and fields of view (FOV). ...In this paper, we develop an x-rays dual-FOV optical coupling detection (DFOCD) system for global imaging with high-resolution region of interest (ROI). In DFOCD system, the beam splitter separates lights to form two sub-optical paths, two objectives with different FOV and magnification are used in the two sub-optical paths for dual-FOV imaging. Then a data fusion method is proposed to register and fuse dual-FOV data. Reconstructed images are obtained based on back projection filtering algorithm using fusion data. Dual-FOV data are collected simultaneously in DFOCD system, which precludes artifacts in fusion images from phantom movement or changes in two acquisitions on common micro-CT, and also saves scanning time. Simulation and experimental results show that details in ROI and global morphology of phantoms are correctly reconstructed. Bright ring artifacts of ROI caused by truncated data are corrected in reconstruction images. Therefore, global imaging with high-resolution ROI of samples can be obtained by single scan experiment using DFOCD system and data fusion method, which is expected to expand the application of micro-CT.
Flue-cured tobacco production in China is typically over-fertilised and mono-cropped. To understand how this agronomic management affects soil structure and organic matter, this study investigated ...the effect of rotation, fertilizer rate, and manure amendment on the proportion of water stable aggregates and aggregate-associated soil organic carbon (SOC) and total soil nitrogen (TSN) concentrations and stocks in tobacco production. Two tobacco management systems (Tobacco monoculture and Tobacco-rice rotation) with four fertilizer treatments (0, 75, and 112 kg N/ha, and 60 kg N/ha + manure) were established in 1998. After 18 years, soil aggregation and aggregate-associated SOC and TSN were significantly affected by rotation and fertilizer management. Compared to tobacco monoculture and current fertilizer management, rotation and manure amendment increased macroaggregate (>250 μm) proportion and geometric mean diameter and decreased the proportion of microaggregates and silt-clay sized fractions (<250 μm). Simultaneously, rotation and manure amendment increased macroaggregate-associated SOC and TSN stocks at the expense of the microaggregate and silt-clay size class and their associated SOC and TSN stocks. Rotation and/or manure treatment can maintain satisfactory physico-chemical soil properties through macroaggregate stabilization in tobacco production, which contributes to conserving SOC and TSN stocks.
•Conservation practices for tobacco production are recently developed.•Monocropping and chemical fertilizer degrade soil structure for tobacco production.•Monocropping and chemical fertilizer deplete SOM stocks for tobacco production.•Rotation and manure increased soil macroaggregate fractions for tobacco production.
The working conditions of heavy-duty trucks are very complicated as the diesel shaking and resonance problems, which causes weld tears, separators to fall off, and other failures occur. Through ...experiments and finite element simulation, the natural frequency and vibration mode of a given 400 L diesel tank were calculated to study the influences of structural parameters such as the fill ratio (0.1–0.9), the number of baffle plates (0, 1, 2), the spacing of the plates (240 mm, 400 mm, 560 mm) and the aperture (38 mm, 78 mm, 118 mm) on the modal parameters with the wet mode method. The results of the hammering mode test and the simulation modal analysis agree well with the maximum error is 4.8%; the natural frequency of the diesel tank will increase with fill ratio decrease; the increase of the baffle plate number (0, 1, 2) can effectively increase the first-order natural frequency of the diesel tank, but the change of the natural frequency is not obvious on the higher order; the higher plates spacing has a smaller natural frequency; increasing the aperture will highly increase the natural frequency, 188 mm has better vibration safety.
Single‐molecule force spectroscopy (SMFS) has become a powerful tool in investigating the mechanical unfolding/folding of proteins at the single‐molecule level. Polyproteins made of tandem identical ...repeats have been widely used in atomic force microscopy (AFM)‐based SMFS studies, where polyproteins not only serve as fingerprints to identify single‐molecule stretching events, but may also improve statistics of data collection. However, the inherent assumption of such experiments is that all the domains in the polyprotein are equivalent and one SMFS trajectory of stretching a polyprotein made of n domains is equivalent to n trajectories of stretching a single domain. Such an assumption has not been validated experimentally. Using a small protein NuG2 and its polyprotein (NuG2)4 as model systems, here we use optical trapping (OT) to directly validate this assumption. Our results show that OT experiments on NuG2 and (NuG2)4 lead to identical parameters describing the unfolding and folding kinetics of NuG2, demonstrating that indeed stretching a polyprotein of NuG2 is equivalent to stretching single NuG2 in force spectroscopy experiments and thus validating the use of polyproteins in SMFS experiments.
Direct experimental validation: Using optical tweezers, the equivalency of single‐molecule force spectroscopy trajectories of a single domain and its polyprotein is directly demonstrated on a small protein NuG2. The results not only lay a solid foundation for atomic force microscopy experiments using polyproteins, but also pave the way for other force spectroscopy methods to make use of and benefit from polyproteins.
Minimum quantity lubrication (MQL) technologies using vegetable oil lubricants as cutting fluids have attracted much attention as they have excellent machining performance and are environmentally ...friendly. Nevertheless, oil-based MQL tends to produce high cutting temperatures owning to the low cooling capability of oil lubricants. In this work, an MQL technology that utilizes graphene oxide/silicon dioxide (GO/SiO
2
) hybrid nanoparticle water-based lubricants as cutting fluids was developed, and its tribological and machining characteristics were comparatively investigated using four-ball and milling testing units. The mass ratio of GO to SiO
2
was also varied to achieve optimal performance. The results showed that GO/SiO
2
water-based MQL reduced coefficient of friction (COF) and worn scar diameter (WSD) significantly, and improved machining performance compared with individual GO and SiO
2
water-based MQLs, as well as showed a comparative performance with traditional vegetable oil-based MQL. The superior performance of GO/SiO
2
water-based MQL was attributed to the fact that GO/SiO
2
hybrid nanoparticle additives entered the rubbing interface and formed a composite protecting film consisting of a self-lubrication layer of GO and a tribo-thin layer of SiO
2
, which prevented the interface from direct contact and smoothened asperities.
Deep convolutional neural networks have promoted significant progress in building extraction from high-resolution remote sensing imagery. Although most of such work focuses on modifying existing ...image segmentation networks in computer vision, we propose a new network in this paper, Deep Encoding Network (DE-Net), that is designed for the very problem based on many lately introduced techniques in image segmentation. Four modules are used to construct DE-Net: the inception-style downsampling modules combining a striding convolution layer and a max-pooling layer, the encoding modules comprising six linear residual blocks with a scaled exponential linear unit (SELU) activation function, the compressing modules reducing the feature channels, and a densely upsampling module that enables the network to encode spatial information inside feature maps. Thus, DE-Net achieves state-of-the-art performance on the WHU Building Dataset in recall, F1-Score, and intersection over union (IoU) metrics without pre-training. It also outperformed several segmentation networks in our self-built Suzhou Satellite Building Dataset. The experimental results validate the effectiveness of DE-Net on building extraction from aerial imagery and satellite imagery. It also suggests that given enough training data, designing and training a network from scratch may excel fine-tuning models pre-trained on datasets unrelated to building extraction.
Most protective clothing on the market today cannot provide both comfort properties and protectability, which would not match the requirement for preventing or killing the rapidly growing and ...changing virus. Hence, a novel breathable and waterproof composite fabric used in protective clothing was designed through the hot-press process with three functional layers. The waterproof ability, moisture permeability, mechanical property, electricity and bactericidal ability of three layers and composite fabric were studied. Results showed that the moisture permeability of coated thermoplastic polyurethane (TPU) membrane reached 19854 g m2 d−1. The composite fabric had still excellent moisture permeability of up to 13956 g m2 d−1 and water contact angle of 151.7°. The coated TPU membrane had good tensile strength and acid resistance. The voltage and current of composite fabric after 7 days were approximately 0.336 V and 1.4 μA. The composite fabric had a 97.5 % filtering effect for NaCl aerosols, a 99 % bacteriostatic rate, and the ability to withstand the Phy-X174 phage with a diameter of 0.027 μm. This composite fabric based on the principle of moisture permeability and weak electric field could be used in protective clothing, which would be of theoretical significance and guiding practical production.
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