Traditional image quality assessment (IQA) methods do not perform robustly due to the shallow hand-designed features. It has been demonstrated that deep neural network can learn more effective ...features than ever. In this paper, we describe a new deep neural network to predict the image quality accurately without relying on the reference image. To learn more effective feature representations for non-reference IQA, we propose a two-stream convolution network that includes two subcomponents for image and gradient image. The motivation for this design is using a two-stream scheme to capture different-level information of inputs and easing the difficulty of extracting features from one steam. The gradient stream focuses on extracting structure features in details, and the image stream pays more attention to the information in intensity. In addition, to consider the locally non-uniform distribution of distortion in images, we add a region-based fully convolutional layer for using the information around the center of the input image patch. The final score of the overall image is calculated by averaging of the patch scores. The proposed network performs in an end-to-end manner in both the training and testing phases. The experimental results on a series of benchmark datasets, e.g., LIVE, CISQ, IVC, TID2013, and Waterloo Exploration Database, show that the proposed algorithm outperforms the state-of-the-art methods, which verifies the effectiveness of our network architecture.
The extra-ordinary properties of carbon fiber reinforced polymer (CFRP) composites and its outstanding performance in their structural applications, especially in aerospace industry where high ...strength to weight ratio is highly desirable, have given them a steadfast attention in the engineering materials research world. Drilling of CFRP materials to facilitate holes for component assembly subjects them to various modes of failure due to their anisotropy and in homogeneity. A requisite means of investigation and analysis is therefore required in order to understand these failure modes. Traditionally, the failure modes have been studied through experiments and more recently numerical simulations. There are dozens of finite element (FE) software available for numerical simulation with Abaqus/CAE being the mostly used for composites analysis. The numerical setup is a complicated process requiring some level of expertise in order to get accurate results which can be validated with experimental results. Upcoming researchers find it difficult, and they end up spending much time preparing for a successful simulation due to scattered information in scientific literature about modeling. This article tries to make work easier for new researchers by doing a review of 3D modeling of drilling CFRP using Abaqus/CAE software. The article features models from highly experienced researchers and their validated results with step-by-step setup guidelines. The objective is to provide a basic guideline to new researchers on the appropriate material properties and damage models for a successful and accurate simulation.
Controlling toxigenic Fusarium graminearum (FG) is challenging. A bacterial strain (S76-3, identified as Bacillus amyloliquefaciens) that was isolated from diseased wheat spikes in the field ...displayed strong antifungal activity against FG. Reverse-phase high performance liquid chromatography and electrospray ionization mass spectrometry analyses revealed that S76-3 produced three classes of cyclic lipopeptides including iturin, plipastatin and surfactin. Each class consisted of several different molecules. The iturin and plipastatin fractions strongly inhibited FG; the surfactin fractions did not. The most abundant compound that had antagonistic activity from the iturin fraction was iturin A (m/z 1043.35); the most abundant active compound from the plipastatin fraction was plipastatin A (m/z 1463.90). These compounds were analyzed with collision-induced dissociation mass spectrometry. The two purified compounds displayed strong fungicidal activity, completely killing conidial spores at the minimal inhibitory concentration range of 50 µg/ml (iturin A) and 100 µg/ml (plipastatin A). Optical and fluorescence microscopy analyses revealed severe morphological changes in conidia and substantial distortions in FG hyphae treated with iturin A or plipastatin A. Iturin A caused leakage and/or inactivation of FG cellular contents and plipastatin A caused vacuolation. Time-lapse imaging of dynamic antagonistic processes illustrated that iturin A caused distortion and conglobation along hyphae and inhibited branch formation and growth, while plipastatin A caused conglobation in young hyphae and branch tips. Transmission electron microscopy analyses demonstrated that the cell walls of conidia and hyphae of iturin A and plipastatin A treated FG had large gaps and that their plasma membranes were severely damaged and separated from cell walls.
Deep autoencoder has been extensively used for anomaly detection. Training on the normal data, the autoencoder is expected to produce higher reconstruction error for the abnormal inputs than the ...normal ones, which is adopted as a criterion for identifying anomalies. However, this assumption does not always hold in practice. It has been observed that sometimes the autoencoder "generalizes" so well that it can also reconstruct anomalies well, leading to the miss detection of anomalies. To mitigate this drawback for autoencoder based anomaly detector, we propose to augment the autoencoder with a memory module and develop an improved autoencoder called memory-augmented autoencoder, i.e. MemAE. Given an input, MemAE firstly obtains the encoding from the encoder and then uses it as a query to retrieve the most relevant memory items for reconstruction. At the training stage, the memory contents are updated and are encouraged to represent the prototypical elements of the normal data. At the test stage, the learned memory will be fixed, and the reconstruction is obtained from a few selected memory records of the normal data. The reconstruction will thus tend to be close to a normal sample. Thus the reconstructed errors on anomalies will be strengthened for anomaly detection. MemAE is free of assumptions on the data type and thus general to be applied to different tasks. Experiments on various datasets prove the excellent generalization and high effectiveness of the proposed MemAE.
Unidirectional Glass Fiber Reinforced Plastic (GFRP) laminates were prepared by inserting three-dimensional (3D) CNTs/carbon black film or CNTs/graphene oxide (GO) film into the laminates to improve ...the interlaminar performance. The effects of low-temperature cycles (35 cycles between −58 °C and room temperature (RT)) on the samples were investigated, and the damage caused to the reinforcement layer was directly detected by comparing the interlaminar images. By comparing the experimental results of the double cantilever beam (DCB) and end notch bending (ENF) test, the optimising effect of the new composite film (CNTs/carbon black film) on the interlaminar fracture toughness was verified. The results showed that the interlaminar fracture toughness of CNTs/GO film and CNTs/carbon black film in modes I (ENF test) and II (DCB test) was similar and superior to that of CNTs film. Regarding the effect of the low-temperature cycles on the samples, the change of CNTs/carbon black film and CNTs/GO film is also lower than that of CNTs film. Finally, the matrix interface and failure mechanisms of the interlaminar reinforcement were investigated by scanning electron microscope (SEM).
•The superiority of the structure was verified.•The effects of the low-temperature cycle on the samples were investigated by low-temperature treatment.•Damage caused by the low-temperature cycle to the reinforcing layer was directly proved by comparing the interlaminar images.
Catechins, caffeine, and theanine as three important metabolites in the tea leaves play essential roles in the formation of specific taste and shows potential health benefits to humans. However, the ...knowledge on the dynamic changes of these metabolites content over seasons, as well as the candidate regulatory factors, remains largely undetermined.
An integrated transcriptomic and metabolomic approach was used to analyze the dynamic changes of three mainly metabolites including catechins, caffeine, and theanine, and to explore the potential influencing factors associated with these dynamic changes over the course of seasons. We found that the catechins abundance was higher in Summer than that in Spring and Autumn, and the theanine abundance was significantly higher in Spring than that in Summer and Autumn, whereas caffeine exhibited no significant changes over three seasons. Transcriptomics analysis suggested that genes in photosynthesis pathway were significantly down-regulated which might in linkage to the formation of different phenotypes and metabolites content in the tea leaves of varied seasons. Fifty-six copies of nine genes in catechins biosynthesis, 30 copies of 10 genes in caffeine biosynthesis, and 12 copies of six genes in theanine biosynthesis were detected. The correlative analysis further presented that eight genes can be regulated by transcription factors, and highly correlated with the changes of metabolites abundance in tea-leaves.
Sunshine intensity as a key factor can affect photosynthesis of tea plants, further affect the expression of major Transcription factors (TFs) and structural genes in, and finally resulted in the various amounts of catechins, caffeine and theaine in tea-leaves over three seasons. These findings provide new insights into abundance and influencing factors of metabolites of tea in different seasons, and further our understanding in the formation of flavor, nutrition and medicinal function.
Osteoporosis seriously disturbs the life of people. Meanwhile, inhibition or weakening of osteogenic differentiation is one of the important factors in the pathogenesis of osteoporosis. It was ...reported that miR-27a-3p reduced the symptoms of osteoporosis. However, the mechanism by which miR-27a-3p in osteogenic differentiation remains largely unknown.
To induce the osteogenic differentiation in MC3T3-E1 cells, cells were treated with osteogenic induction medium (OIM). RT-qPCR was used to evaluate the mRNA expression of miR-27a-3p and CRY2 in cells. The protein levels of CRY2, Runt-related transcription factor 2 (Runx2), osteopontin (OPN), osteocalcin (OCN) and the phosphorylation level of extracellular regulated protein kinases (ERK) 1/2 in MC3T3-E1 cells were evaluated by western blotting. Meanwhile, calcium nodules and ALP activity were tested by alizarin red staining and ALP kit, respectively. Luciferase reporter gene assay was used to analyze the correlation between CRY2 and miR-27a-3p.
The expression of miR-27a-3p and the phosphorylation level of ERK1/2 were increased by OIM in MC3T3-E1 cells, while CRY2 expression was decreased. In addition, OIM-induced increase of calcified nodules, ALP content and osteogenesis-related protein expression was significantly reversed by downregulation of miR-27a-3p and overexpression of CRY2. In addition, miR-27a-3p directly targeted CRY2 and negatively regulated CRY2. Meanwhile, the inhibitory effect of miR-27a-3p inhibitor on osteogenic differentiation was reversed by knockdown of CRY2 or using honokiol (ERK1/2 signal activator). Furthermore, miR-27a-3p significantly inhibited the apoptosis of MC3T3-E1 cells treated by OIM. Taken together, miR-27a-3p/CRY2/ERK axis plays an important role in osteoblast differentiation.
MiR-27a-3p promoted osteoblast differentiation via mediation of CRY2/ERK1/2 axis. Thereby, miR-27a-3p might serve as a new target for the treatment of osteoporosis.
Helical milling is being adapted to machine holes that facilitate component assembling in the aerospace industry. It is superior to conventional drilling in many ways including low cutting forces, ...reduced tool wear and improved hole quality. The main objective of this study was to establish a better method of milling holes in CFRP/Ti stack. Four strategies were studied experimentally and the results compared including thrust forces, delamination and temperatures. In the first and second strategies, it was found that composite laminate experience less damage when machined in the configuration CFRP/Ti compared to Ti/CFRP. The third and fourth strategies employed three steps to achieve the required diameter while alternating the composite-metal stack. It was found that a multi-step milling strategy leads to the best quality holes as the subsequent steps eliminate the damage caused by the first step while only utilizing peripheral cutting thus minimum forces. Thrust forces were found to have an almost linear relationship with the feed rates and an inverse relationship with the spindle speeds for all the strategies studied.
A comprehensive experimental investigation was carried out to evaluate the toughening behavior of polyethersulfone (PES) and carbon nanotubes (CNTs) interleaf with similar thicknesses for carbon ...fiber reinforced polymer (CFRP) composites under mode II fracture loading. The influence of four different environmental conditions (room temperature, −55 °C, temperature changes between −55 °C and 80 °C, and salt spray) on mode II fracture toughness (GIIC) was discussed. The flexural property of CFRP composites before and after introducing interleaves was employed at room temperature. Effective diffusion of CNTs is a key means to enhance the interlaminar properties of CFRP composites without sacrificing the bending properties. Results show that CNTs and PES/CNT1 (when the CNTs content is 1 wt%) interleaves could enhance the GIIC by 118.4% and 317.81%, respectively. Hybrid PES/CNTs interleaf exhibited higher mode II fracture toughness and greater adaptability to the environment. The fracture behavior was demonstrated with experimental results and related scanning electron microscopy (SEM) images.
The laminates of unidirectional (UD) Glass Fiber Reinforced Plastic (GFRP) were prepared by inserting Toner/epoxy film (as a comparison) and CNTs/epoxy film between layers to optimize the ...interlaminar performance. The effect of temperature variation on the interlaminar properties of materials has yet to be identified in practical applications. To explore the impact of low-temperature cycle (21 cycles between −58 °C and RT) on the specimens and the strengthening mechanism of the two epoxy films, interlaminar shear strength (ILSS) test, end notch flexure (ENF) test and double cantilever beam (DCB) test were prepared and carried out. The results showed that the interlaminar fracture toughness of GFRP embedded with the CNTs/epoxy film was superior to that of GFRP without film and embedded with the Toner/epoxy film in modes I (based on DCB) and II (based on ENF). The interlaminar shear strength was greatly enhanced by the interlaminar integration of CNTs/epoxy film. The impact of low-temperature cycle on the interlaminar performance of CNTs/epoxy enhanced GFRP was not significant, and the effect on the interlaminar properties of CNTs/epoxy enhanced GFRP was minimal compared with the other two kinds of specimens. The microstructure of the interlaminar strengthening interface was further studied by scanning electron microscopy (SEM).
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