High-sensitivity complex refractive index sensing is proposed and experimentally demonstrated, favoring with sharp Fano resonance at 1550 nm wavelength based on subwavelength grating waveguide (SWG) ...micro-ring resonator. The micro-ring is composed by trapezoidal silicon pillars with subwavelength period to enhance the light-analyte overlap and get high quality factor as well. One straight SWG waveguide is side coupled with the micro-ring, which is specially designed to produce partial Fabry-Perot (FP) effect. Due to the interaction of resonant state of micro-ring and partial FP effect in straight waveguide, a sharp asymmetrical Fano resonance is formed at 1550 nm wavelength. Benefit from the large light-analyte overlap of the SWG waveguide structure and the sharp asymmetrical Fano resonance in spectrum, high theoretical sensitivities of 366 nm/RIU and 9700/RIU can be realized for the real part (n) and the imaginary part (κ) of refractive index respectively. We also experimentally demonstrate the sensing for glucose solution concentrations, and high experimental sensitivity of 363nm/RIU is obtained for n, and for κ the experimental results are also in well agreement with the simulation results.
Early diagnosis and monitoring of SARS-CoV-2 virus is essential to control COVID-19 outbreak. In this study, we propose a promising surface enhanced Raman scattering (SERS)-based COVID-19 biosensor ...for ultrasensitive detection of SARS-CoV-2 virus in untreated saliva. The SERS-immune substrate was fabricated by a novel oil/water/oil (O/W/O) three-phase liquid-liquid interfaces self-assembly method, forming two layers of dense and uniform gold nanoparticle films to ensure the reproducibility and sensitivity of SERS immunoassay. The detection was performed by an immunoreaction between the SARS-CoV-2 spike antibody modified SERS-immune substrate, spike antigen protein and Raman reporter-labeled immuno-Ag nanoparticles. This SERS-based biosensor was able to detect the SARS-CoV-2 spike protein at concentrations of 0.77 fg mL−1 in phosphate-buffered saline and 6.07 fg mL−1 in untreated saliva. The designed SERS-based biosensor exhibited excellent specificity and sensitivity for SARS-CoV-2 virus without any sample pretreatment, providing a potential choice for the early diagnosis of COVID-19.
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•A new SERS-based COVID-19 biosensor was developed for ultrasensitive detection of SARS-CoV-2 virus.•A novel three-phase interfaces self-assembly method was applied for fabricating the SERS-immune substrate.•The SERS-immune substrate assembled by highly dense and uniform Au NPs can improve the reproductivity of SERS immunoassay.•The biosensor can detect the SARS-CoV-2 spike protein at ultra-low concentration of 6.07 fg mL−1 in untreated saliva.•The biosensor exhibits excellent specificity and sensitivity for SARS-CoV-2 virus without any sample pretreatment.
Intelligent fault diagnosis methods based on deep learning becomes a research hotspot in the fault diagnosis field. Automatically and accurately identifying the incipient micro-fault of rotating ...machinery, especially for fault orientations and severity degree, is still a major challenge in the field of intelligent fault diagnosis. The traditional fault diagnosis methods rely on the manual feature extraction of engineers with prior knowledge. To effectively identify an incipient fault in rotating machinery, this paper proposes a novel method, namely improved the convolutional neural network-support vector machine (CNN-SVM) method. This method improves the traditional convolutional neural network (CNN) model structure by introducing the global average pooling technology and SVM. Firstly, the temporal and spatial multichannel raw data from multiple sensors is directly input into the improved CNN-Softmax model for the training of the CNN model. Secondly, the improved CNN are used for extracting representative features from the raw fault data. Finally, the extracted sparse representative feature vectors are input into SVM for fault classification. The proposed method is applied to the diagnosis multichannel vibration signal monitoring data of a rolling bearing. The results confirm that the proposed method is more effective than other existing intelligence diagnosis methods including SVM, K-nearest neighbor, back-propagation neural network, deep BP neural network, and traditional CNN.
Recently, environmental and ecological concerns are increasing due to the usage of petroleum-based products so the synthesis of ultra-fine chemicals and functional materials from natural resources is ...drawing a tremendous level of attention. Nanocellulose, a unique and promising natural material extracted from native cellulose, may prove to be most ecofriendly materials that are technically and economically feasible in modern times, minimizing the pollution generation. Nanocellulose has gained tremendous attention for its use in various applications, due to its excellent special surface chemistry, physical properties, and remarkable biological properties (biodegradability, biocompatibility, and non-toxicity). Various types of nanocellulose, viz. cellulose nanofibrils (CNFs), cellulose nanocrystals (CNCs), and bacterial nanocellulose (BNC), are deeply introduced and compared in this work in terms of sources, production, structures and properties. The metal and metal oxides especially zinc oxide nanoparticles (ZnO-NPs) are broadly used in various fields due to the diversity of functional properties such as antimicrobial and ultraviolet (UV) properties. Thus, the advancement of nanocellulose and zinc oxide nanoparticles (ZnO-NPs)-based composites materials are summarized in this article in terms of the preparation methods and remarkable properties with the help of recent knowledge and significant findings (especially from the past six years reports). The nanocellulose materials complement zinc oxide nanoparticles, where they impart their functional properties to the nanoparticle composites. As a result hybrid nanocomposite containing nanocellulose/zinc oxide composite has shown excellent mechanical, UV barrier, and antibacterial properties. The nanocellulose based hybrid nanomaterials have huge potential applications in the area of food packaging, biopharmaceuticals, biomedical, and cosmetics. Thus the functional composite materials containing nanocellulose and zinc oxide will determine the potential biomedical application for nanocellulose.
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•Consolidated study on cellulose and nanocellulose structure, sources and applications•Reviewing various extraction techniques of nanocellulose, their types, properties, and characteristics•All recognized excellent properties and recent advancement of nanocellulose/ZnO-NPs composite materials are presented.•Challenges and future viewpoints of ZnO nanoparticles with nanocellulose materials are discussed.
Microbiomes are important for crop performance. However, a deeper knowledge of crop-associated microbial communities is needed to harness beneficial host-microbe interactions. Here, by assessing the ...assembly and functions of maize microbiomes across soil types, climate zones, and genotypes, we found that the stem xylem selectively recruits highly conserved microbes dominated by Gammaproteobacteria. We showed that the proportion of bacterial taxa carrying the nitrogenase gene (nifH) was larger in stem xylem than in other organs such as root and leaf endosphere. Of the 25 core bacterial taxa identified in xylem sap, several isolated strains were confirmed to be active nitrogen-fixers or to assist with biological nitrogen fixation. On this basis, we established synthetic communities (SynComs) consisting of two core diazotrophs and two helpers. GFP-tagged strains and
N isotopic dilution method demonstrated that these SynComs do thrive and contribute, through biological nitrogen fixation, 11.8% of the total N accumulated in maize stems. These core taxa in xylem sap represent an untapped resource that can be exploited to increase crop productivity.
Studying the spatial and temporal changes of grassland soil organic carbon (SOC) is helpful in promote the management of regional ecosystem carbon sinks. Grazing is one of the main ways of rational ...utilization of grassland. Different grazing intensities will affect the change of SOC density. Under different grazing intensity and management measures in Zhangye grassland, this study uses the parameter localized CENTURY model to simulate the temporal and spatial variations of SOC density from 1970 to 2022. The results showed that long-term light grazing reduced the average SOC by 195.114 g·m−2 and 1.91%. Moderate and severe grazing, respectively, for a long time made the total SOC density loss of 5.21% and 17.69%. In a short period, mild and moderate grazing reduced total SOC first and then increased it. Under light grazing, total SOC density appeared higher relative changes in the southeast, and lower in the northwest and central. There was no significant difference in the relative changes of total SOC between steppe and desert grasslands under light grazing. The decrease range of steppe was gradually greater than that in desert grassland. Since different management measures were implemented in some sampling sites in 2017, we divided the study period into two periods, 1970–2016 and 2017–2022. The implementation of degraded grassland improvement, fallow grazing, and rotational grazing would increase the total SOC density and mild SOC density, rotational grazing > degraded grassland improvement > rest grazing. Rotational grazing and the improvement of degraded grassland increased the density of active and inert SOC, while resting grazing decreased the density of SOC.
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•Waste cotton fabrics could be used as feedstock for MCC production.•EMC is obtained with low HCl concentration under hydrothermal condition.•The maximum yield and DP of EMC were ...achieved in the low cost system.•EMC has the cellulosic structure and had good thermal stability.
A large amount of accumulated waste cotton fabrics (WCFs) have caused environmental problem and depletion of resources. The extraction of microcrystalline cellulose as value-added products is one of the effective ways to the recycling of WCFs. This study aimed to extract microcrystalline cellulose from WCFs by the hydrothermal method and compare the extracted microcrystalline cellulose (EMC) with Avicel PH101 microcrystalline cellulose (MCC). The EMC was extracted under hydrothermal conditions (solid–liquid ratio 1:30, HCl concentration 0.6 mol/L, 150 °C, 100 min), with a yield and the degree of polymerization of 85.54% and 228, respectively. The samples were characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis and contact angle testing. The detailed analyses showed that the properties of EMC prepared from WCFs are similar to those of commercial MCC. The results indicated that WCFs is a critical and potential low-cost raw material to prepare MCC.
Numerous people die of paraquat (PQ) poisoning every year in the world. Although several studies regarding paraquat (PQ) poisoning have been conducted, the metabolic changes in plasma remain unknown. ...In this study, the metabolomics of 15 PQ poisoned patients with plasma PQ concentrations in excess of 0.1 µg/mL and 16 healthy volunteers were investigated. The plasma samples were evaluated through the use of gas chromatography-mass spectrometry (GC/MS) and analyzed by partial least-squares discriminant analysis (PLS-DA). Based on the metabolomics data, a support vector machine (SVM) discrimination model was developed. The results showed the plasma levels of urea, glucose oxime and L-phenylalanine decreased and cholesterol increased in PQ poisoned patients in comparison to healthy volunteers. The SVM discrimination model was developed, and performed with a high degree of accuracy, to distinguish PQ poisoned patients from healthy volunteers. In conclusion, metabolic pathways including the urea cycle, and amino acid, glucose, and cholesterol metabolism were impaired after PQ poisoning. An SVM discrimination model, based on metabolomics data, was established and may become a new powerful tool for the diagnosis of PQ poisoning.
HOTAIR, a long intervening non-coding RNA (lincRNA), associates with the Polycomb Repressive Complex 2 (PRC2) and is reported to reprogram chromatin organization and promote tumor progression. ...However, little is known about the roles of this gene in the development of chemoresistance phenotype of lung adenocarcinoma (LAD). Thus, we investigated the involvement of HOTAIR in the resistance of LAD cells to cisplatin. In this study, we show that HOTAIR expression was significantly upregulated in cisplatin-resistant A549/DDP cells compared with in parental A549 cells. Knockdown of HOTAIR by RNA interference could resensitize the responses of A549/DDP cells to cisplatin both in vitro and in vivo. In contrast, overexpression of HOTAIR could decrease the sensitivity of A549 and SPC-A1 cells to cisplatin. We also found that the siRNA/HOTAIR1-mediated chemosensivity enhancement was associated with inhibition of cell proliferation, induction of G0/G1 cell-cycle arrest and apoptosis enhancement through regulation of p21(WAF1/CIP1) (p21) expression. Also, pcDNA/p21or siRNA/p21 could mimic the effects of siRNA/HOTAIR1 or pcDNA/HOTAIR on the sensitivity of LAD cells to cisplatin. Importantly, siRNA/p21 or pcDNA/p21 could partially rescue the effects of siRNA/HOTAIR1 or pcDNA/HOTAIR on both p21 expression and cisplatin sensitivity in LAD cells. Further, HOTAIR was observed to be significantly downregulated in cisplatin-responding LAD tissues, and its expression was inversely correlated with p21 mRNA expression. Taken together, our findings suggest that upregulation of HOTAIR contributes to the cisplatin resistance of LAD cells, at least in part, through the regulation of p21 expression.
The hydrogen storage properties of the Scandium (Sc) atom modified Boron (B) doped porous graphene (PG) system were studied based on the density functional theory (DFT). For a single Sc atom, the ...most stable adsorption position on B-PG is the boron-carbon hexagon center after doping with the B atom. The corresponding adsorption energy of Sc atoms was -4.004 eV. Meanwhile, five H
molecules could be adsorbed around a Sc atom with the average adsorption energy of -0.515 eV/H
. Analyzing the density of states (DOS) and the charge population of the system, the adsorption of H
molecules in Sc-B/PG system is mainly attributed to an orbital interaction between H and Sc atoms. For the H
adsorption, the Coulomb attraction between H
molecules (negatively charged) and Sc atoms (positively charged) also played a critical role. The largest hydrogen storage capacity structure was two Sc atoms located at two sides of the boron-carbon hexagon center in the Sc-B/PG system. Notably, the theoretical hydrogen storage capacity was 9.13 wt.% with an average adsorption energy of -0.225 eV/H
. B doped PG prevents the Sc atom aggregating and improves the hydrogen storage effectively because it can increase the adsorption energy of the Sc atom and H
molecule.
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