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Ultraviolet (UV–C), a no residual environmentally friendly physical treatment, plays an important role in delaying the senescence in fruit. In this study, 'Lingwu long' jujubes were treated with UV-C (5 kJ m−2) to investigate the impacts of cell wall degrading enzymes (CWDEs) activities, reactive oxygen species (ROS) metabolism, and phenylpropanoid metabolism under storage at 4 ± 1 °C for 30 d. UV-C treatment reduced respiration rate and decay index. Treated fruit exhibited lower polygalacturonase (PG), pectinate lyases (PL), cellulase (Cel), and β-galactosidase (β-gal) activities which ultimately delayed the reduction of firmness. UV-C treatment increased hydrogen peroxide (H 2 O 2), free radical scavenging ability, and superoxide dismutase (SOD) and catalase (CAT) activities, reduced superoxide anion (O 2 −) and malondialdehyde (MDA) content. In addition, ascorbate peroxidase (APX), glutathione reductase (GR), dehydroascorbate reductase (DHAR), and monodehydroascorbate reductase (MDHAR) activities were activated by UV-C treatment, leading to glutathione (GSH) and ascorbic acid (AsA) increased. Besides, phenolic compounds of jujube fruit treated with UV-C were also increased, which might be due to the enhanced phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H), and 4-coumarate-CoA ligase (4CL) activities. In conclusion, UV-C was recommended for improving overall quality and alleviating senescence in jujube fruit. • UV-C delayed the softening rate in jujube fruit. • UV-C inhibited membrane lipid peroxidation in jujube fruit. • UV-C improved the reactive oxygen species scavenging ability in jujube fruit. • UV-C activated the phenylpropane metabolic pathway. • UV-C treatment showed great potential to delay senescence in jujube fruit. [ABSTRACT FROM AUTHOR]

Hyperspectral imaging (HSI), a non-destructive method combining image and spectral techniques to obtain image and spectral information of target objects, and qualitative and quantitative analyses using spectral data, has been widely used in agricultural product detection. This study was conducted to assess the feasibility of using HSI (900–1700 nm) for rapid determination of myoglobin contents (DeoMb, OxyMb and MetMb) in nitrite-cured mutton during refrigerated storage. The data were analyzed using evolutionary computing methods, including partial least squares regression (PLSR) and least squares support vector machines (LSSVM). Corresponding feature wavelengths were then selected by using competitive adaptive reweighted sampling (CARS), variable combination population analysis (VCPA) and interval variable iterative space shrinkage approach (iVISSA) respectively. The simplified iVISSA-PLSR model showed the best performance for determining DeoMb with R p of 0.9017 and RMSEP of 2.3509. In addition, the best model for OxyMb was CARS-PLSR, with R p of 0.9661 and RMSEP of 2.3762. Moreover, the CARS-LSSVM model showed a better performance with a higher R p (0.8931) and a lower RMSEP (3.2743) for MetMb. Furthermore, the overall performance of wavelength selection methods in terms of CARS (R pDeoMb ≥ 0.8943, R pOxyMb ≥ 0.9607, R pMetMb ≥ 0.8910) and iVISSA (R pDeoMb ≥ 0.8976, R pOxyMb ≥ 0.9568, R pMetMb ≥ 0.8880) were equivalent and slightly better than VCPA (R pDeoMb ≥ 0.8711, R pOxyMb ≥ 0.9573, R pMetMb ≥ 0.8808). The results demonstrated that effective wavelength selection method can improve the performance of HSI system for the determination of myoglobin contents in comparison to full wavelength. • Feature wavelengths were selected by CARS, VCPA, iVISSA and iVISSA-CARS. • PLSR and LSSVM models were developed to measure myoglobin contents (DeoMb, OxyMb and MetMb) of nitrite-cured mutton. • The correlation coefficient of simpled model is acceptable for measuring myoglobin contents. [ABSTRACT FROM AUTHOR]

This study aimed to develop simplified models for rapid and nondestructive monitoring myoglobin contents (DeoMb, MbO 2 and MetMb) during refrigerated storage of Tan sheep based on a hyperspectral imaging (HSI) system in the spectral range of 400–1000 nm. Partial least squares regression (PLSR) and least-squares support vector machines (LSSVM) were applied to correlate the spectral data with the reference values of myoglobin contents measured by a traditional method. In order to simplify the LSSVM models, competitive adaptive reweighted sampling (CARS) and Interval variable iterative space shrinkage approach (iVISSA) were used to select key wavelengths. The new CARS-LSSVM models of DeoMb and MbO 2 yielded good results, with R2p of 0.810 and 0.914, RMSEP of 1.127 and 2.598, respectively. The best model of MetMb was new iVISSA-CARS-LSSVM, with an R2p of 0.915 and RMSEP of 2.777. The overall results from this study indicated that it was feasible to predict myoglobin contents in Tan sheep using HSI. [ABSTRACT FROM AUTHOR]

Searching for highly efficient and Pt-free electrocatalysts with comparable hydrogen evolution reaction (HER) activities to the benchmark Pt/C catalyst is highly demanded for developing renewable water electrolysis system but still remains challenging. In the current work, low loading of P modified ultrafine Rh nanoparticles encapsulated in N, P dual-doped carbon layers (Rh–P@NPC) have been prepared through a facile polymerization-impregnation followed by high-temperature pyrolysis process. Benefiting from the unique core-shell structural advantages and synergistic effect of Rh–P and NPC components, the resulting Rh–P@NPC catalyst not only exhibits remarkable electrocatalytic activity for HER in the whole pH range with a low overpotential of 31 mV, 65 mV, and 130 mV to drive a current density of 10 mA cm−2 in 0.5 M H 2 SO 4 , 1.0 M KOH, and 1.0 M PBS, respectively, but also demonstrates high durability. It is worth to note that all these HER performances are on a par with commercial Pt/C catalysts for HER. This synthetic strategy provides possibility for the fabrication of carbon-based heterostructures with high catalytic activity and durability in harsh environments. • Low loading of P-doped Rh encapsulated in N, P-doped carbon layers are prepared. • The Rh–P@NPC with high surface area with enable full expose of active species. • The Rh–P@NPC exhibits excellent activity and stability for HER in the whole pH range. • The P-doped Rh and NPC can synergistically enhance the HER activity and stability. [ABSTRACT FROM AUTHOR]

The amount and chemical state of myoglobin are often relevant to meat color, which is one of the important characteristics of meat freshness and wholesomeness. To precisely determine OxyMb and MetMb contents in mutton, the feasibility of optimization detection technology of spectral image fusion was explored. Three methods were used to select characteristic wavelengths while textural features of muscle tissue were derived. Compared among all models, LSSVM models coupled with spectra and textural parameters all performed better than these PLSR models. The iVISSA-COR-LSSVM model for OxyMb prediction achieved a good performance of R2 C = 0.9525, RMSEC = 2.2955, R2 P = 0.8956, and RMSEP = 3.0036. The more effective prediction performances emerged from VCPA-IRIV-COR-LSSVM model with R2 C = 0.8809, RMSEC = 2.2009, R2 P = 0.8353, and RMSEP = 3.2096 for MetMb. In final, the pseudo color maps of OxyMb and MetMb distribution were generated. This study demonstrated that the data fusion method furnishes a new approach to rapidly evaluate myoglobin content. • Better results were obtained by iVISSA and VCPA-IRIV identified wavebands. • Data fusion was used for enhancing hyperspectral prediction performance of myoglobin value. • LSSVM models built for predicting OxyMb and MetMb contents showed good results. • Distribution maps of OxyMb and MetMb values were visualized. [ABSTRACT FROM AUTHOR]

A hyperspectral imaging technique was used for acquiring reflectance images to identify common defects (bruise, insect-infestetation and cracks) on jujube fruit. Hyperspectral images of jujubes were evaluated from the regions of interest through principal component analysis (PCA) to select five optimal wavelengths (420,521,636,670,679 nm) from 300 samples in the spectral region of 400–1000 nm and four important wavelength (1028,1118,1359,1466 nm) in the region of 978–1586 nm. Compared with support vector machine (SVM) models, the soft independent modeling of class analogy (SIMCA) models of intact, cracked, bruised, and insect-infested jujubes based on five wavelengths in NIR showed good performance with high classification rates of 96%, 96%, 93.9% and 95.6%, respectively. This research demonstrates the feasibility of implementing hyperspectral imaging for identifying common defects and enhancing the product quality and marketability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Excessive intake of salt is associated with several negative health effects. • The use of natural substances to replace salt in food is a growing trend. • Reduced salt in processed meat products affects quality and shelf life. • Umami substances can lower NaCl in meat products without quality loss. • Natural umami substances can increase the water-holding capacity and reduce lipid oxidation of meat products. Sodium is one of the essential additives in meat processing, but excessive sodium intake may increase risk of hypertension and cardiovascular disease. However, reducing salt content while preserving its preservative effect, organoleptic properties, and technological characteristics poses challenges. In this review, the mechanism of salt reduction of umami substances was introduced from the perspective of gustation-taste interaction, and the effects of the addition of traditional umami substances (amino acids, nucleotides, organic acids(OAs)) and natural umami ingredients (mushrooms, seaweeds, tomatoes, soybeans, tea, grains) on the sensory properties of the meat with reduced-salt contents were summarized. In addition, the impacts of taste enhancers on eating quality (color, sensory, textural characteristics, and water-holding capacity (WHC)), and processing quality (lipid oxidation, pH) of meat products (MP) and their related mechanisms were also discussed. Among them, natural umami ingredients exhibit distinct advantages over traditional umami substances in terms of enhancing quality and nutritional value. On the basis of salt reduction, natural umami ingredients improve the flavor, texture, WHC and antioxidant capacity. This comprehensive review may provide the food industry with a theoretical foundation for mitigating salt consumption through the utilization of umami substances and natural ingredients. [ABSTRACT FROM AUTHOR]

The detection of meat texture is of great value because it is the key factor that drives consumer purchasing decisions. In this study, a hyperspectral imaging (HSI) system was utilized to determine the texture parameters of Tan mutton. In order to observe the influence of mutton spectra during different refrigeration periods for modeling, hyperspectral images of the Tan mutton samples were collected in the 900–1700 nm spectral range, and the correction models of Tan mutton texture parameters were established. The four machine learning algorithms, such as partial least squares regression (PLSR), least squares support vector machine (LSSVM), random forest (RF), and decision trees (DT), were developed to establish the spectral models based on the characteristic bands selected by different extraction strategies including interval variable iterative space shrinkage approach (iVISSA), competitive adaptive reweighted sampling (CARS), successive projection algorithm (SPA) and variable combination population analysis (VCPA). The results showed that the LSSVM-iVISSA-CARS models exhibited excellent performance in predicting hardness and gumminess with root-mean-square errors (RMSEP) of 5.259 and 3.051 as well as the coefficient of determination for the prediction data set (R p 2) of 0.986 and 0.984 respectively. Good performances were achieved with R p 2 of 0.987 and RMSEP of 4.970 with the LSSVM-iVISSA-SPA model for chewiness, respectively. Therefore, HSI has potential for the evaluation and prediction of texture parameters in Tan mutton. • Spectra at 900–1700 nm was applied for detecting texture parameters of Tan mutton. • The OSC and MC methods were both utilized to preprocess X-block and Y-block. • Informative wavelengths were selected using iVISSV-CARS and iVISSV-SPA approaches. • The LSSVM model yielded the best result in predicting hardness, gumminess and chewiness of Tan mutton. [ABSTRACT FROM AUTHOR]

Abstract: Sm3+- and Eu3+-doped rare-earth borate glasses (Li2O–BaO–La2O3–B2O3) have been fabricated and characterized optically. The density, refractive index, optical absorption, Judd-Ofelt parameters, and spontaneous transition probabilities have been measured, calculated and analyzed. Sm3+ and Eu3+ emit intense reddish-orange and red lights under blue and UV light excitations, respectively. In Sm3+ and Eu3+ co-doped glasses, the excitation wavelength range of Eu3+ emission is broadened owing to the energy transfer from Sm3+ to Eu3+. This broadening makes the Ar+ 488nm wavelength laser a powerful excitation source for Eu3+ fluorescence. The rare-earth doped glasses with various visible emissions are useful for developing new color light sources, fluorescent display devices, UV-sensor and tunable visible lasers. [Copyright &y& Elsevier]

To investigate the changes in colour and chlorophyll levels in vacuum-precooled green beans during storage, kinetic models and shelf life prediction models of these quality indices were established by reaction kinetics and the Arrhenius equation. Linear regression analysis was used to study the changes in colour and chlorophyll levels during 12 d of storage at 0 °C, 5 °C, 10 °C and 25 °C, and the relationship between chlorophyll level and total colour difference (ΔE) was also determined. The results showed that the colour and chlorophyll levels retained in vacuum-precooled green beans were better than those in the control group during storage. A linear regression analysis revealed that the change rate constants of colour parameters (L*, a*, b* and ΔE) and chlorophyll levels followed the Arrhenius law dependence on temperature. Colour and chlorophyll levels were successfully described by zero-order and first-order reactions, respectively. In addition, the shelf life based on ΔE and chlorophyll level changes of 10% was similar to that at a cut-off score of 6 by sensory evaluation. It was suggested that the kinetics model could accurately predict the shelf life and changes of colour and chlorophyll levels in vacuum-precooled green beans during storage. • Vacuum precooling resulted in higher retention colour of green beans during storage. • Kinetics modelling was used to map green beans color changes during storage. • The applicability of the Arrhenius law during storage was investigated. • Chlorophyll was a predictor of colour quality index during storage. [ABSTRACT FROM AUTHOR]

CTAB-Surface-Modified-TiO 2 nanocatalysts were synthesized via a microemulsion combine hydrothermal method. The experimental result showed that the nitric acid concentration and hydrothermal temperature had important influence on the photocatalytic activity of samples. When the nitric acid concentration was 2 M and hydrothermal temperature was 120 °C, photocatalytic activity of sample was highest. It could achieve 99.99% degradation rate of rhodamine B (RhB) within 60 min visible light irradiation. The superior photocatalytic activity was mainly ascribed to that the CTAB molecule groups could abound the surface state of TiO 2 and the abundant surface state could generate shallow trap levels to trap electron and thus enhanced light absorption as well as reduced electron-hole pair recombination. [ABSTRACT FROM AUTHOR]

Ho 3+ /Yb 3+ co-doped Bi 2 WO 6 (Ho 3+ /Yb 3+ -Bi 2 WO 6 ) nanopowders were synthesized by a simple hydrothermal method. Crystal structure, morphology and chemical composition of the samples were characterized by XRD, SEM, TEM and EDS. The effects of some critical synthesis conditions on the upconversion luminescence properties were studied in detail. Under the excitation of 980 nm laser diode, Ho 3+ /Yb 3+ -Bi 2 WO 6 upconversion nanopowder with strongest luminescence intensity was obtained when the concentration of Ho 3+ and Yb 3+ were 1 mol%, 5.0 mol% respectively, and calcined at 600 °C. Moreover, excitation power studies showed that a two-photon process was involved in the upconversion emissions. The probable upconversion luminescence mechanism was discussed according to the energy transfer process. [ABSTRACT FROM AUTHOR]

Yb 2 O 3 :Ho 3+ nanocrystalline powders were synthesized through a solid state reaction method. X-ray diffraction analysis and field emission scanning electron microscopy were used to analyze the phase composition and morphology of the powders. Then under the 980 nm excitation of laser diode, the fluorescence of the crystals was studied via a fluorescence spectrometer. The green and red emissions centered on 551 and 668 nm were observed, and the green band dominated the emission spectrum. The effect of the concentration of Ho 3+ on the upconversion luminescence intensity was discussed and the possible upconversion emission mechanism was explained. It indicates that like other metal oxide nanoparticles, Yb 2 O 3 could also be a potential host material for doping to prepare the upconversion phosphor. [ABSTRACT FROM AUTHOR]

SrAl 2 O 4 :Eu 3+ down-conversion (DC) nanocrystals were synthesized by a sol–gel method and then doped in TiO 2 as a photoanode in dye-sensitized solar cells (DSSCs). Differential thermal analysis, fourier transform infrared spectroscopy, X-ray diffraction and Brunauer–Emmet–Teller analysis confirmed the formation of SrAl 2 O 4 :Eu 3+ nanocrystals with diameters of ∼47 nm, pore size of ∼25 nm, sintering temperature of 1300 °C. The photoluminescence and UV–vis absorption spectra of the SrAl 2 O 4 :Eu 3+ revealed a DC from ultraviolet light to visible light which matched the strong absorbing region of the N719 dye. The photoelectric conversion efficiency of the DSSCs with a TiO 2 photoanode doped with 3 wt% SrAl 2 O 4 :Eu 3+ was 20% higher than that with a pure TiO 2 photoanode. This phenomenon could be mainly explained by SrAl 2 O 4 :Eu 3+ nanocrystals’ ability of DC and increased the short-circuit current density. It could be minorly due to the p-type doping effect and slightly improved the open-circuit voltage. [ABSTRACT FROM AUTHOR]

SrTiO 3 :Sm 3+ @SiO 2 (STS@SiO 2 ) core–shell nanoparticles were fabricated by Stöber method after a simple hydrothermal process and then being introduced into the TiO 2 photoanode to assemble dye–sensitized solar cells (DSSCs). X–ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR) and transmission electron microscope (TEM) analysis confirmed the formation of core–shell nanoparticles with cubic structured SrTiO 3 :Sm 3+ (STS) as core, SiO 2 as shell. The photo–fluorescence (PL) and ultraviolet–visible (UV–Vis) absorption spectra of photoanodes with different STS@SiO 2 content indicate a down–conversion from ultraviolet light to visible light which matched the strong absorbing region of the N719 dye. Compared with the pure TiO 2 and STS doped TiO 2 photoanode, STS@SiO 2 doped TiO 2 photoanode showed a greater photovoltaic efficiency. The photoelectric conversion efficiency ( η ) of 5.07% for 10 wt% STS@SiO 2 doped TiO 2 –based DSSC was higher than that of 3.72% for pure TiO 2 –based DSSC and 4.29% for 10 wt% STS doped TiO 2 –based DSSC. This phenomenon could be explained by STS@SiO 2 core–shell nanoparticles’ triple ability to extend spectral response range to the ultraviolet region, suppress the recombination of electron–electrolyte and lengthen the light traveling distance in the photoanode by the scattering. [ABSTRACT FROM AUTHOR]

• The R spectra were transformed into two spectral units, A and K-M. • IVISSA algorithm was used to select characteristic wavelengths. • PLS-DA and SVM algorithms were used to identify sound and bruised jujubes. • A-Raw-iVISSA-PLS-DA was the optimal classification discriminant model. Bruising is one of the major challenges appearing in the postharvest grading and processing of Lingwu long jujubes, which leads to quality deterioration and microbial infection. In the present work, the spectra of reflectance (R), absorbance (A) and Kubelka-Munk (K-M) in Lingwu were obtained by hyperspectral imaging, and applied to non-destructively detect bruising symptoms. Spectra were preprocessed and characteristic wavelengths were selected by competitive adaptive reweighted sampling (CARS) and the interval variable iterative space shrinkage approach (iVISSA). Classification discriminant models were constructed by partial least squares-discriminant analysis (PLS-DA) and support vector machine (SVM). By comparison, the results revealed that the A-raw-iVISSA-PLS-DA model showed the lowest errors in cross-validation, while the number of feature variables was the lowest accounting for 28.8 %, and the accuracies of the calibration and cross validation were 88.9 % and 100.0 %, respectively. In particular, this study demonstrated the feasibility to detect the early bruising degree in Lingwu long jujubes based on absorbance spectrum. Consequently, it also laid a foundation for future studies about detecting early bruising in small fruit with a rapid and non-destructive spectral-optical measurement. [ABSTRACT FROM AUTHOR]

Highlights: [•] TiO2 and Si-OCP composite coatings were synthesized on zirconia ceramics. [•] Low temperature degradation of ZrO2 substrate could be suppressed by TiO2 layer. [•] Si-doped OCP coating was firstly synthesized by biomimetic method. [ABSTRACT FROM AUTHOR]

• This study presents a new approach for the application of shallow geothermal energy. • Difference in temperatures of heat pipe systems with different diameter of vertical part is insignificant. • The heat resistance of the heat pipes only accounted for approximately 1% of the total thermal resistance. • The maximum heat transfer power of the heat pipe is 202 W. Owing to the depletion of global fossil energy and the increasing environmental awareness of environmental protection, the use of shallow geothermal energy has been receiving widespread attention. In this study, two sets of groundwater-based heat pipe (GBHP) systems were fabricated to explore the application of heat pipes in shallow geothermal energy and tested through lawn heating experiments during the winter. Results of the experiment showed that the vertical diameter of the heat pipe did not have any significant effect on its heat transfer performance, and the maximum difference in temperature between the horizontal section of the east and west heat pipes during the observation period was 1.6 °C. Furthermore, the heat pipe exhibited good isothermicity with a constant operation, with the average temperature difference between the condensation and evaporation sections were 2.1 °C. The heat pipe also exhibited good thermal conductivity, the thermal resistance accounting for only 1% of the total thermal resistance in the heat transfer process. The maximum heat transfer power of a single heat pipe was found to be 202 W. This study presents a new approach for the application of shallow geothermal energy. [ABSTRACT FROM AUTHOR]

The Ag 2 O/Ag 2 S/CuBi 2 O 4 double Z-scheme heterostructures photocatalysts with different Ag 2 O proportion were successfully synthesized via the hydrothermal and coprecipitation methods. Compared with those of pure CuBi 2 O 4 and Ag 2 S, the absorption of near-infrared light of Ag 2 O/Ag 2 S/CuBi 2 O 4 samples is enhanced, their photocurrent intensity is significantly increased, and the charge transfer resistance is reduced. Obviously, all the Ag 2 O/Ag 2 S/CuBi 2 O 4 samples exhibited significantly enhanced photoactivities under the UV, Vis or NIR light irradiation. Of them, under the simulated sunlight, Ag 2 O/Ag 2 S/CuBi 2 O 4 with 36.7 wt% Ag 2 O showed the highest catalytic activity with RhB degradation rate of 99.2% and the reduction rate of Cr(VI) of 53%. The construction of double Z-scheme heterojunction reduced the recombination of electrons and holes and improved the separation efficiency of electron. Moreover, Ag 2 S and Ag 2 O broadened the photoresponse range to a wide spectrum, and then improved the photocatalytic efficiency. In addition, the stability of Ag 2 O/Ag 2 S/CuBi 2 O 4 containing 36.7 wt% Ag 2 O was demonstrated through three successive cycling experiment. Image 1 • A new Ag 2 O/Ag 2 S/CuBi 2 O 4 double Z-scheme heterostructures were synthesized. • RhB degradation and Cr (IV) reduction under UV, Vis or NIR light was investigated. • Ag 2 O/Ag 2 S/CuBi 2 O 4 contained Ag 2 O of 36.7 wt% exhibits the highest photoactivities. • The improved photocatalytic activity could be attributed to double Z-scheme heterojunction. • This study provides a great way to obtain stable heterostructure photocatalyst. [ABSTRACT FROM AUTHOR]