Advanced techniques capable of early, rapid, and nondestructive detection of the impacts of drought on fruit tree and the measurement of the underlying photosynthetic traits on a large scale are ...necessary to meet the challenges of precision farming and full prediction of yield increases. We tested the application of hyperspectral reflectance as a high-throughput phenotyping approach for early identification of water stress and rapid assessment of leaf photosynthetic traits in citrus trees by conducting a greenhouse experiment. To this end, photosynthetic CO2 assimilation rate (Pn), stomatal conductance (Cond) and transpiration rate (Trmmol) were measured with gas-exchange approaches alongside measurements of leaf hyperspectral reflectance from citrus grown across a gradient of soil drought levels six times, during 20 days of stress induction and 13 days of rewatering. Water stress caused Pn, Cond, and Trmmol rapid and continuous decline throughout the entire drought period. The upper layer was more sensitive to drought than middle and lower layers. Water stress could also bring continuous and dynamic changes of the mean spectral reflectance and absorptance over time. After trees were rewatered, these differences were not obvious. The original reflectance spectra of the four water stresses were surprisingly of low diversity and could not track drought responses, whereas specific hyperspectral spectral vegetation indices (SVIs) and absorption features or wavelength position variables presented great potential. The following machine-learning algorithms: random forest (RF), support vector machine (SVM), gradient boost (GDboost), and adaptive boosting (Adaboost) were used to develop a measure of photosynthesis from leaf reflectance spectra. The performance of four machine-learning algorithms were assessed, and RF algorithm yielded the highest predictive power for predicting photosynthetic parameters (R2 was 0.92, 0.89, and 0.88 for Pn, Cond, and Trmmol, respectively). Our results indicated that leaf hyperspectral reflectance is a reliable and stable method for monitoring water stress and yield increase, with great potential to be applied in large-scale orchards.
This review summarizes the strengthening mechanisms of reduced activation ferritic/martensitic (RAFM) steels. High-angle grain boundaries, subgrain boundaries, nano-sized M
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, and MX carbide ...precipitates effectively hinder dislocation motion and increase high-temperature strength. M
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carbides are easily coarsened under high temperatures, thereby weakening their ability to block dislocations. Creep properties are improved through the reduction of M
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carbides. Thus, the loss of strength must be compensated by other strengthening mechanisms. This review also outlines the recent progress in the development of RAFM steels. Oxide dispersion-strengthened steels prevent M
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precipitation by reducing C content to increase creep life and introduce a high density of nano-sized oxide precipitates to offset the reduced strength. Severe plastic deformation methods can substantially refine subgrains and MX carbides in the steel. The thermal deformation strengthening of RAFM steels mainly relies on thermo-mechanical treatment to increase the MX carbide and subgrain boundaries. This procedure increases the creep life of TMT(thermo-mechanical treatment) 9Cr-1W-0.06Ta steel by ∼20 times compared with those of F82H and Eurofer 97 steels under 550°C/260 MPa.
•Structural characterization of two polysaccharides from Dendrobium officinale were described.•DOP performed the hypoglycemic activity via stimulating GLP-1 secretion in STZ-induced diabetic rats and ...STC-1 cells.•Ca2+/CaM/CaMKII and MAPK pathways might involve in the intracellular DOP-induced GLP-1 secretion.•The repeated unit of backbone of DOP-1 and DOP-2 might be the effective unit of DOP-induced GLP-1 secretion.
Two polysaccharides, named DOP-1 and DOP-2, with molecular weights of 6.8 kDa and 14.3 kDa, respectively, were isolated and purified from the stems of Dendrobium officinale. Monosaccharide composition, Fourier-transform infrared spectroscopy, methylation, and nuclear magnetic resonance analyses indicated that DOP-1 and DOP-2 may have a backbone consisted of →4)-β-d-Glcp-(1→, →4)-β-d-Manp-(1→, →4)-2-O-acetyl-β-d-Manp-(1→ and →4)-3-O-acetyl-β-d-Manp-(1→. In vivo assays showed that D. officinale polysaccharides (DOPs) exerted significant hypoglycemic effects accompanying increased serum insulin and glucagon-like peptide-1 (GLP-1) levels in streptozotocin-induced diabetic rats. Further in vitro experiments showed that DOP-induced GLP-1 secretion was inhibited by an intracellular calcium chelator, a Ca2+/calmodulin-dependent protein kinase (CaMK) II inhibitor, a specific calcium-sensing receptor antagonist, and a p38-mitogen-activated protein kinases (MAPK) inhibitor. These results indicated that DOPs may decrease fasting blood sugar levels by stimulating GLP-1 secretion and that intracellular DOP-induced GLP-1 secretion involved the Ca2+/calmodulin/CaMKII and MAPK pathways.
Pansharpening is normally utilized to take full advantage of all the available spectral and spatial information that are derived from a low-spatial-resolution multispectral (MS) image and its ...associated high-spatial-resolution (HR) panchromatic (PAN) image, respectively, producing a fused MS image with high spectral and spatial resolutions. Many methods have been recently developed based on convolutional neural networks (CNNs) for the pansharpening task, but most of them still have some drawbacks: 1) The information cannot efficiently flow in their simple stacked convolutional architectures, thereby hindering the representation ability of the networks. 2) They are commonly trained using supervised learning, which does not only require an extra effort to produce the simulated training data, but can also lead to scale-related problems in the fusion results. In this article, we propose a novel unsupervised CNN-based pansharpening method to overcome these limitations. Specifically, we design an iterative network architecture, in which a PAN-guided strategy and a set of skip connections are adopted to continuously extract and fuse the features from the input, thus enhancing the information reuse and transmission. Besides, we propose a new loss function for unsupervised training in which the relationships between the input MS and PAN images and the fused MS image are used to design the spatial constrains and spectral consistency, respectively. The typical quality index with no-reference is also added to this function to further adjust the spectral and spatial qualities. The designed loss function allows the network to be learned only on input images, without any hand-crafted labels (reference HR MS image). We evaluated the effectiveness of our designed network architecture and the combined loss function, and the experiments testify that our unsupervised strategy can also obtain promising results with minor spectral and spatial distortions compared with other traditional and supervised methods.
Regulating degradation rate and moderate pH micro-environment for biodegradable magnesium alloys face huge challenge. The chemical and morphological characteristics of micro-arc oxidation (MAO) and ...chitosan (CS) composite coatings, fabricated on Mg-4Li-1Ca alloy, are analyzed through field-emission scanning electronic microcopy, energy dispersive X-ray spectroscopy, X-ray diffraction and Fourier transform infrared spectroscopy. Corrosion resistance of the samples is evaluated via hydrogen evolution, potentiodynamic polarization and electrochemical impedance spectroscopy in Hank's solution. Results indicated that the MAO and CS coating enhances the corrosion resistance and antibacterial growth activity. With increasing immersion time, the degradation of the MAO/CS coatings gives rise to a decrease in pH value and leads to a rapid increase in hydrogen evolution rate after an immersion in Hank's solution after 100 h. The MAO/CS coatings retain the solution pH at a moderate level (≤8.25). A novel self-degradation mechanism of the MAO/CS coating on Mg-Li-Ca alloy is proposed due to the fact that MAO/CS coating is cathodic relative to the substrate.
The degradation of micro-arc oxidation coating (MAO)/chitosan (CS) coating decreases solution pH value at lower level (≤8.25) in comparison to MAO coating. A self-degradation mechanism of CS-based materials is proposed. And the degradation process experiences three stages: (1) initial water diffusion, absorption and hydration of CS coatings; (2) gradual decrease in molecular weight; and (3) scission and dissolution of oligomers and monomers. Thus, the degraded CS releases -NH3+ ions, which react with MgO of MAO coating and lead to the formation of Mg2+ ions and water along with the micro-cracks and pores of the MAO coating. Display omitted
•MAO/CS coating improves corrosion resistance and antibacterial effect of the alloy.•Degradation of MAO/CS coating retains a lower pH of ≤8.25 during long immersion.•MAO/CS coating is negative and cathodic relative to its substrate.•Self-degradation mechanism of MAO/CS coating on Mg-4Li-1Ca alloy is proposed.
Background & Aims Neutrophil infiltration has been linked to clinical outcome of various cancer types. However, its role in hepatocellular carcinoma (HCC) is unclear. In this study, we investigated ...prognostic values for intratumoral and peritumoral neutrophils in HCC patients undergoing curative resection. Methods The expression of CD66b, CD8, TGF-beta, and CD34 was assessed by immunohistochemistry in tissue microarrays containing paired intratumoral and peritumoral tissues from 197 patients receiving curative resection for HCC. Prognostic values for these and other clinicopathologic factors were evaluated. Results Intratumoral CD66b+ neutrophils significantly correlated with CD8+ T cells ( r = 0.240, p = 0.004), TGF-beta expression ( p = 0.012), BCLC stage ( p = 0.016), and early recurrence ( p = 0.041). Increased intratumoral neutrophils were significantly associated with decreased RFS/OS ( p = 0.001 and p <0.001, respectively) in univariate analysis and were identified as an independent prognostic factor (HR = 1.845, 95% CI = 1.169–2.911, p = 0.008 for RFS; HR = 2.578, 95% CI = 1.618–4.106, p <0.001 for OS) in multivariate analysis. Intratumoral neutrophil-to-CD8+ T cell ratio (iNTR) better predicted the outcome in terms of minimum p values. Intratumoral neutrophils were also demonstrated to be statistically predictive for RFS/OS in the normal AFP subgroup, small HCC subgroup, and validation cohort. However, peritumoral neutrophils were not associated with the outcome of HCC. Conclusions The presence of intratumoral neutrophils was a poor prognostic factor for HCC after resection. Intratumoral neutrophil-to-CD8+ T cell ratio was a better predictor of outcome.
The D1- and D2-dopamine receptors (D1R and D2R), which signal through Gs and Gi, respectively, represent the principal stimulatory and inhibitory dopamine receptors in the central nervous system. D1R ...and D2R also represent the main therapeutic targets for Parkinson’s disease, schizophrenia, and many other neuropsychiatric disorders, and insight into their signaling is essential for understanding both therapeutic and side effects of dopaminergic drugs. Here, we report four cryoelectron microscopy (cryo-EM) structures of D1R-Gs and D2R-Gi signaling complexes with selective and non-selective dopamine agonists, including two currently used anti-Parkinson’s disease drugs, apomorphine and bromocriptine. These structures, together with mutagenesis studies, reveal the conserved binding mode of dopamine agonists, the unique pocket topology underlying ligand selectivity, the conformational changes in receptor activation, and potential structural determinants for G protein-coupling selectivity. These results provide both a molecular understanding of dopamine signaling and multiple structural templates for drug design targeting the dopaminergic system.
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•Structures of dopamine receptor D1R-Gs complexes with three agonists•Structure of dopamine receptor D2R-Gi complex bound to bromocriptine at 2.8 Å resolution•Highly similar structures between the active states of D1R and β2- adrenergic receptor•Structural determinants for ligand and G protein selectivity between D1R and D2R•G-protein biased agonism of SKF83959 toward D1R from structural and functional studies
Near-atomic resolution structures of activated D1R-Gs and D2R-Gi signaling complexes, together with multiple functional studies, reveal the conserved catechol agonist binding mode in D1R and the structural basis that underlies D1R and D2R ligand selectivity and G protein-coupling specificity.
Blue-phase liquid crystal (BPLC) is considered as the next-generation liquid crystal display material, but its practical application is seriously affected by a narrow temperature range and a long ...research period. In this paper, we used inkjet printing technology to prepare BPLC materials with high throughput, and try to use machine vision technology to test BPLC with high throughput. The “standard curve method” for establishing each printing channel and the “vector matching method” for searching the chromaticity value of the minimum distance were proposed to improve the accuracy of inkjet printing BPLC materials. For a large number of sample-phase images, we propose a machine learning method to identify the liquid crystal phase. In this paper, for the first time, the high-throughput preparation and high-throughput detection of 1080 BPLC samples with five common components by a comprehensive experimental method has been successfully realized. The results are helpful to improve the research efficiency of blue-phase materials and provide a theoretical basis and practical guidance for rapid screening of multi-component BPLC materials.
Meso-substituted boron dipyrromethenes (BODIPYs) provide a potential and innovative strategy for the synergistic construction of aggregation-induced emission (AIE) probes and fluorescent rotors for ...monitoring cellular viscosity changes, which play critical roles in understanding the function of viscosity in its closely associated diseases. Therefore, for the first time, a BODIPY-based fluorescent probe (1) with a rotatable meso-benzothiazole group was rationally designed and synthesized, showing both good viscosity-responsive and AIE properties. Probe 1 through direct linkage with the thiazole group, showed nearly no emission in low viscous solvents; however, a strong emission at 534 nm appeared and increased gradually with the increase in viscosity, attributing to the efficient restriction of the rotatable meso-benzothiazole group. The intensity (log I 534) displayed a good linear relationship with viscosity (log η) in the viscous range of 0.59–945 cP in methanol/glycerol mixtures. Interestingly, 1 showed enhanced emission at 534 nm in 70% water compared to pure acetonitrile due to the aggregation-induced inhibited rotations. Cellular imaging suggested that 1 could successfully sense lysosomal viscosity changes induced by lipopolysaccharide, nystatin, low temperature, and dexamethasone in living cells, which could be further applied in autophagy monitoring by tracing viscosity changes. As a comparison, its analogue 2 directly linking with the phenyl group showed no viscosity-responsive or AIE properties. Therefore, for the first time, we reported a meso-benzothiazole-BODIPY-based fluorescent rotor with AIE and lysosomal viscosity-responsive properties in nervous cells, which was further applied in monitoring autophagy, and this work thus could provide an innovative strategy for the design of potential AIE and viscosity-responsive probes.
Hepatitis B virus (HBV) infection remains a major health problem worldwide. Maintenance of the covalently closed circular DNA (cccDNA), which serves as a template for HBV RNA transcription, is ...responsible for the failure of eradicating chronic HBV during current antiviral therapy. cccDNA is assembled with cellular histone proteins into chromatin, but little is known about the regulation of HBV chromatin by histone posttranslational modifications. In this study, we identified silent mating type information regulation 2 homolog 3 (SIRT3) as a host factor restricting HBV transcription and replication by screening seven members of the sirtuin family, which is the class III histone deacetylase. Ectopic SIRT3 expression significantly reduced total HBV RNAs, 3.5‐kb RNA, as well as replicative intermediate DNA in HBV‐infected HepG2‐Na+/taurocholate cotransporting polypeptide cells and primary human hepatocytes. In contrast, gene silencing of SIRT3 promoted HBV transcription and replication. A mechanistic study found that nuclear SIRT3 was recruited to the HBV cccDNA, where it deacetylated histone 3 lysine 9. Importantly, occupancy of SIRT3 on cccDNA could increase the recruitment of histone methyltransferase suppressor of variegation 3‐9 homolog 1 to cccDNA and decrease recruitment of SET domain containing 1A, leading to a marked increase of trimethyl‐histone H3 (Lys9) and a decrease of trimethyl‐histone H3 (Lys4) on cccDNA. Moreover, SIRT3‐mediated HBV cccDNA transcriptional repression involved decreased binding of host RNA polymerase II and transcription factor Yin Yang 1 to cccDNA. Finally, hepatitis B viral X protein could relieve SIRT3‐mediated cccDNA transcriptional repression by inhibiting both SIRT3 expression and its recruitment to cccDNA. Conclusion: SIRT3 is a host factor epigenetically restricting HBV cccDNA transcription by acting cooperatively with histone methyltransferase; these data provide a rationale for the use of SIRT3 activators in the prevention or treatment of HBV infection. (Hepatology 2018).
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