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Remaining useful life (RUL) prediction of aircraft engines is significant in the health monitoring, operation, and maintenance of aircraft. Capturing more comprehensive device degradation trends at different time scales and extracting long-term dependencies effectively among elements in long time series are two challenges in the field of aircraft engine RUL estimation. To address the aforementioned challenges, this paper proposes a novel multiscale Hourglass-Transformer (MHT) aircraft engine RUL prognostics. Specifically, an hourglass-shaped multiscale feature extractor (HME) is designed based on one-dimensional convolutional neural network, which can scale the time sequence into multi-time scales for feature fusion. Then, a transformer network is employed to further extract features from the fused feature map and output the RUL. To enhance inter-scale data attention, a pyramid self-attention mechanism is employed in both the encoder and decoder. Finally, the superiority and effectiveness of this approach are verified on the Commercial Modular Aero-Propulsion System Simulation (C-MAPSS) dataset. Furthermore, the robustness and generalization capability of this method are further validated on New Commercial Modular Aero-Propulsion System Simulation (N-CMAPSS) dataset. • A novel multiscale Hourglass-Transformer is developed for aircraft engine RUL prognostics. • An hourglass-shaped multiscale feature extractor is designed based on one-dimensional convolutional neural network. • A transformer network is employed to further extract features. • Pyramid self-attention mechanism is adopted to reduce space complexity. [ABSTRACT FROM AUTHOR]

In the present study, apple peel polyphenols (APP) were incorporated into chitosan (CS) to develop a novel functional film. Scanning electron microscopy, Fourier transform-infrared spectroscopy and thermogravimetric analyses were performed to study the structure, potential interaction and thermal stability of the prepared films. Physical properties including moisture content, density, color, opacity, water solubility, swelling ration and water vapor permeability were measured. The results revealed that addition of APP into CS significantly improved the physical properties of the film by increasing its thickness, density, solubility, opacity and swelling ratio whereas moisture content and water vapor permeability were decreased. Tensile strength and elongation at break of the CS-APP film with 1% APP was 16.48 MPa and 13.33%, respectively, significantly lower than those for CS control film. Thermal stability of the prepared films was decreased while antioxidant and antimicrobial activities of the CS-based APP film were significantly increased. CS-APP film with 0.50% APP concentration exhibited good mechanical and antimicrobial properties, indicating that it could be developed as bio-composite food packaging material for the food industry. [ABSTRACT FROM AUTHOR]

[Display omitted] • Tea polysaccharide (TPS) from Taiping Houkui green tea was prepared. • TPS could escape digestion in the upper gut, and then utilized by gut microbiota. • TPS increases SCFAs productions, and was more able to increase acetic acid level. • Fermentation metabolites of TPS could remarkably reduce lipid accumulation in vitro. Taiping Houkui (TPHK) is a well-known green tea in China. However, tea polysaccharide (TPS) from TPHK green tea and its potential health-promoting functions are less well known. Thus, the potential prebiotic function of TPS were investigated. The result showed TPS could escape digestion by host enzymes in the upper gut, and then further broken down and utilized by gut microbiota in large intestine. On the other hand, TPS could modulate the gut microbiota, including decreasing the ratio of Firmicutes/Bacteroidetes, promoting the growth of Bacteroides , and improving the pathway of amino acid metabolism. TPS could increase the productions of short-chain fatty acids (SCFAs). Moreover, TPS showed a limited effect on the triglyceride (TG) level in a HepG2 cell model, whereas, the fermentation solution of TPS could remarkably reduce lipid accumulation in cell. Thus, TPS could be developed as a potential antiobesogenic candidate by remodeling the gut microbiota and its metabolites. [ABSTRACT FROM AUTHOR]

In the present study, pear polyphenol oxidase (PPO) was purified, immobilized and applied for the synthesis of theaflavin-3,3′-digallate (TF3). Firstly, PPO of pear ( Pyrus bretschneideri Rehd cv. Huangguan) was purified 24.36-fold in specific activity with a recovery of 6.77% by sequential use of precipitation with 70% saturated ammonium sulfate and chromatography of DEAE-Sepharose Fast Flow column. The purified pear PPO, found to be a dimer of identical subunits of molecular mass 35 kDa, was then successfully immobilized onto Fe 3 O 4 /chitosan nanoparticles via glutaraldehyde coupling reaction. Finally, TF3 was effectively synthesized by applying the immobilized PPO as biocatalyst with epicatechin gallate (ECG) and epigallocatechin-3- O -gallate (EGCG) as substrates, and the maximum yield of TF3 was 42.23% based on the amount of ECG added. In addition, the immobilized enzyme still remained 85% of its initial ability after successive usage of 8 cycles and could be stored for 30 days with less loss of activity. All the results suggest that the developed procedure is quite useful and has great potential for synthesis of TF3 and other theaflavins. [ABSTRACT FROM AUTHOR]

A new parameter-free framework for calibration enhancement (PFCE) was proposed for dealing with the near-infrared (NIR) spectral inconsistency and maintaining the prediction ability of the calibration model under different conditions. The calibration issues encountered in the maintenance with or without using standards, and even the enhancement between instruments have been thoroughly addressed. The general calibration maintenance/enhancement cases were formulated into non-supervised PFCE (NS-PFCE), semi-supervised PFCE (SS-PFCE), and full-supervised PFCE (FS-PFCE). The NS-PFCE made use of both the provided master and slave spectra of standard samples to construct a maintained calibration slave model by implementing a correlation constraint on the regression coefficients. The SS-PFCE and FS-PFCE methods integrated the slave spectra and reference information of standard samples at the same time into the slave spectral calibration, and thus a maintenance or enhancement model could be achieved for the slave spectra, in particular measured on different instruments. The use of dataset1 comprised of 655 pharmaceutical tablets measured on two NIR spectrometers and datset2 containing 117 plant leaf samples in two mesh sizes has demonstrated that the PFCE framework had a significant effect on enhancing the predictions of the slave spectra in the models. The root mean square errors of prediction (RMSEPs) of either active pharmaceutical ingredient (API) amount in tablets or reducing sugar content in plant leaf samples from the slave spectra approached to or were lower than those values predicted from the master spectra in the master models established with the partial least-squares (PLS) regression method. The advantage of PFCE was parameter-free and efficient. First, the method could be flexibly employed in scientific or applicative environment with no regard to the parameter specification. Second, the performance of NS-PFCE was comparable to the classical calibration maintenance methods, yet the SS-PFCE and FS-PFCE could enhance the prediction ability to a level widely considered as the upper boundary of classical calibration maintenance methods reached.The source code of the method is available at https://github.com/JinZhangLab/PFCE. Image 1 • New, efficient parameter-free framework for calibration enhancement (PFCE) of NIR spectroscopy. • Formulating the calibration maintenance and enhancement into non-supervised, semi-supervised, and full-supervised cases. • Dealing with spectral inconsistency and maintaining prediction ability of calibration model under different conditions. • PFCE constructing a maintained or enhanced calibration model by a correlation constraint on the regression coefficients. • The PFCE model resulting in more accurate predicition. [ABSTRACT FROM AUTHOR]

To detect more credibly the changes in the crystal structure of chickpea starch during processing treatments, two methods, a deconvolution method based on X-ray diffraction (XRD) pattern of starch and a moisture analysis method based on starch moisture content, were applied to determine the relative crystallinity ( RC ) of A- and B-type polymorphs ( RC A and RC B ) in the same chickpea starch sample. It was found that the values of RC A for chickpea starch samples determined by these two methods were close and showed similar trend. The results suggested that these two methods could be used to estimate RC A in the same chickpea starch sample and provide mutual corroboration. Based on the deconvolution method, it was observed that the crystalline region of chickpea starch was less susceptible to α-amylase hydrolysis than its amorphous region, and B-type polymorph in chickpea starch was more resistant to α-amylase hydrolysis than A-type polymorph. [ABSTRACT FROM AUTHOR]

Highlights: [•] Quality enhancement of apple juice by thermosonication has been investigated. [•] Thermosonication enabled inactivation of enzymes and microbes of apple juice. [•] Retention of ascorbic acid and polyphenolic compounds was observed. [•] The pH, titratable acidity and °Brix remained unaffected. [•] The technique could be efficiently utilized for apple juice processing. [ABSTRACT FROM AUTHOR]

Highlights: [•] Sonication could enhance the individual polyphenolic compounds of apple juice. [•] It could improve the sugar contents, some mineral elements and total carotenoids. [•] Sonication did not affect the total anthocyanins and electrical conductivity. [•] Sonication showed a potential to enhance the phytonutrients of apple juice. [ABSTRACT FROM AUTHOR]

Fresh apple juice treated with ultrasound (for 0, 30, 60 and 90min, at 20°C, 25kHz frequency) was evaluated for different physico-chemical, Hunter color values, cloud value, antioxidant capacity, scavenging activity on 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical, ascorbic acid, total phenolics, flavonoids, flavonols and microbial characteristics. No significant effect of sonication was observed on pH, total soluble solids (°Brix) and titratable acidity of apple juice. Sonication significantly improved ascorbic acid, cloud value, phenolic compounds, antioxidant capacity, DPPH free radical scavenging activity and differences in Hunter color values. Moreover, significant reduction in microbial population was observed. Findings of the present study suggested that sonication treatment could improve the quality of apple juice. It may successfully be employed for the processing of apple juice with improved quality and safety from consumer’s health point of view. [ABSTRACT FROM AUTHOR]