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Apple quality is closely related to its cultivar and origin. However, the apple quality characteristics of different cultivars and origins are unclear. The hypothesis that some quality indicators can effectively distinguish the cultivar and origin of apples. The result indicated that the discriminant accuracy of the models was above 90%, and the multilayer perceptron neural network (MLP–NN) model was superior to the linear discriminant analysis (LDA) model. The identification accuracy of cultivars was higher than origins. The main reason was that the single fruit weight, vitamin C, total soluble solid, soluble sugar, sweetness value, sorbitol, glucose, fructose, sucrose, malic acid, quinic acid and citric acid of ‘Fuji’ apples were significantly higher than ‘Gala’ apples. This study provides a foundation for the quality evaluation and further geographical traceability studies of apples. Further studies related to the regulatory mechanism of environmental conditions on apple quality characteristics should be explored for theoretical confirmation.

A green and efficient ultrasonic-assisted acidic natural deep eutectic solvents for the extraction of anthocyanins from Aronia Melanocarpa was developed. The extraction conditions were optimized by the artificial neural networks and genetic algorithms, and the stability and antioxidant activity of anthocyanins extracts were investigated. A series of acidic natural deep eutectic solvents were prepared using betaine and organic acids as hydrogen bond acceptor and hydrogen bond donor respectively. Their physical and chemical properties such as density, viscosity, pH value were measured. The structure and formation mechanism of natural deep eutectic solvents were studied by infrared spectroscopy. The optimal extraction conditions were optimized by artificial neural network combined with genetic algorithm. The photostability, thermal stability and antioxidant activity of anthocyanins extract were evaluated. The experimental results showed that the natural deep eutectic solvents formed by the hydrogen bond interaction between betaine and lactic acid had the characteristics of density as low as 1.19, viscosity as low as 24.75 mPa·s and pH as 2.89. The optimal extraction conditions were as follows: betaine and lactic acid were used to prepare natural deep eutectic solvents, molar ratio was 1:3, water content was 32%, ultrasonic power was 124 W, ultrasonic time was 24 min and initial ultrasonic temperature was 32 ℃. Under this condition, the anthocyanins extraction yield reached 23.62 mg/g. Compared with traditional solvents and other methods, the method is green, efficient and simple to operate. The results of stability and antioxidant experiments showed that light can accelerate the degradation of anthocyanins in the extract. When the temperature was higher than 50 ℃, the thermal degradation of anthocyanins accelerated with the first-order kinetic degradation constant k>0.0234. When the mass concentration was 200 μg/mL, the DPPH free radical scavenging rate and total antioxidant capacity of anthocyanins extracts were 62.30% and 6.39 mmol/L FeSO4·7H2O equivalent, and at a mass concentration of 30 μg/mL, the ABTS+ free radical scavenging rate of anthocyanins extracts was 85.14%. The antioxidant activity of anthocyanins extracts was significantly (P

Island tourism is a popular form of tourism today. The Beibu Gulf islands are rich in resources, which has made the tourism booming. Qixing Island in Beibu Gulf locates in low latitude, has rich biodiversity, rich and diverse tourism resources. The ecological environment in the island is pleasant and has important protection and development value. The tourism resources of Qixing Island were investigated and classified by field investigation, questionnaire survey and document sorting, to discuss the development orientation and development plan of Qixing Island, put forward protection measures such as inheriting local culture, building mangrove base and developing characteristic tourism projects such as bicycle tour around the island and net fishing, so as to provide scientific basis for the sustainable development of islands in Guangxi.

As a highly economic small fruit crop, blueberry is enjoyed by most people in terms of color, taste, and rich nutrition. To better understand its coloring mechanism on the process of ripening, an integrative analysis of the metabolome and transcriptome profiles was performed in three blueberry varieties at three developmental stages. In this study, 41 flavonoid metabolites closely related to the coloring in blueberry samples were analyzed. It turned out that the most differential metabolites in the ripening processes were delphinidin-3-O-arabinoside (dpara), peonidin-3-O-glucoside (pnglu), and delphinidin-3-O-galactoside (dpgal), while the most differential metabolites among different varieties were flavonols. Furthermore, to obtain more accurate and comprehensive transcripts of blueberry during the developmental stages, PacBio and Illumina sequencing technology were combined to obtain the transcriptome of the blueberry variety Misty, for the very first time. Finally, by applying the gene coexpression network analysis, the darkviolet and bisque4 modules related to flavonoid synthesis were determined, and the key genes related to two flavonoid 3′, 5′-hydroxylase (F3′5′H) genes in the darkviolet module and one bHLH transcription factor in the bisque4 module were predicted. It is believed that our findings could provide valuable information for the future study on the molecular mechanism of flavonoid metabolites and flavonoid synthesis pathways in blueberries.

Rapid, accurate, and label-free detection of pathogenic bacteria and antibiotic resistance at single-cell resolution is a technological challenge for clinical diagnosis. Overcoming the cumbersome culture process of pathogenic bacteria and time-consuming antibiotic susceptibility assays will significantly benefit early diagnosis and optimize the use of antibiotics in clinics. Raman spectroscopy can collect molecular fingerprints of pathogenic bacteria in a label-free and culture-independent manner, which is suitable for pathogen diagnosis at single-cell resolution. Here, we report a method based on Raman spectroscopy combined with machine learning to rapidly and accurately identify pathogenic bacteria and detect antibiotic resistance at single-cell resolution. Our results show that the average accuracy of identification of 12 species of common pathogenic bacteria by the machine learning method is 90.73 ± 9.72%. Antibiotic-sensitive and antibiotic-resistant strains of Acinetobacter baumannii isolated from hospital patients were distinguished with 99.92 ± 0.06% accuracy using the machine learning model. Meanwhile, we found that sensitive strains had a higher nucleic acid/protein ratio and antibiotic-resistant strains possessed abundant amide II structures in proteins. This study suggests that Raman spectroscopy is a promising method for rapidly identifying pathogens and detecting their antibiotic susceptibility.

Summary The development of DNA sequencing technology has provided an effective method for studying foodborne and phytopathogenic microorganisms on fruits and vegetables (F & V). DNA sequencing has successfully proceeded through three generations, including the tens of operating platforms. These advances have significantly promoted microbial whole‐genome sequencing (WGS) and DNA polymorphism research. Based on genomic and regional polymorphisms, genetic markers have been widely obtained. These molecular markers are used as targets for PCR or chip analyses to detect microbes at the genetic level. Furthermore, metagenomic analyses conducted by sequencing the hypervariable regions of ribosomal DNA (rDNA) have revealed comprehensive microbial communities in various studies on F & V. This review highlights the basic principles of three generations of DNA sequencing, and summarizes the WGS studies of and available DNA markers for major bacterial foodborne pathogens and phytopathogenic fungi found on F & V. In addition, rDNA sequencing‐based bacterial and fungal metagenomics are summarized under three topics. These findings deepen the understanding of DNA sequencing and its application in studies of foodborne and phytopathogenic microbes and shed light on strategies for the monitoring of F & V microbes and quality control.

Aroma, which plays an essential role in food perception and acceptability, depends on various mixture of volatile organic compounds (VOCs). Meanwhile, as a field of metabolomics, VOC analysis is highly important for aroma improvement and discrimination purposes. In this work, VOCs in pear fruits were determined via headspace solid-phase micro-extraction (HS-SPME) combined with gas chromatography–mass spectrometry (GC–MS) to study variations among different cultivars and storage stages. In 12 cultivars of pear fruits, a total of 121 VOCs were quantified, including 40 esters, 32 alcohols, 16 aldehydes, 13 alkenes, 11 ketones, 4 acids, and 5 other compounds. The types and amounts of VOCs in different cultivars varied dramatically, which were in the range of 13–71 and 3.63–55.65 mg/kg FW (fresh weight), respectively. The Dr. Guyot cultivar showed the highest level of VOCs, both in type and amount. After 21 days storage at 4 °C, total concentration of VOCs increased from initial levels of 50.76 to 101.33 mg/kg FW. Storage at 20 °C made a larger contribution to production for VOCs than that at 4 °C, resulting in the maximum content of VOCs (117.96 mg/kg FW) in fruit after 14 days storage at 4 °C plus 7 days at 20 °C. During storage, the content of esters showed a gradual increase, while the content of alcohols and aldehydes decreased. Based on the results presented, related alcohols were recognized as the intermediates of conversion from aldehydes to esters.

Background: Increasing evidence has shown the beneficial effects of Rhodiola species on metabolic disorders, but their mechanisms are not clear. Hepatic steatosis is closely related to metabolic disorders, we aim to investigate the therapeutic effects of Rhodiola crenulata root (RCR) on fructose-induced hepatic steatosis and explore the underlying mechanisms. Purpose: To observe the effect of Rhodiola crenulata root extract (RCR) on fructose-induced hepatic steatosis in Sprague-Dawley (SD) rats and explore its possible mechanism. Methods: Male Sprague-Dawley rats were treated with liquid fructose in their drinking water over 18 weeks. The extract of RCR was co-administered (once daily by oral gavage) during the last 5 weeks. Liver lipid deposition and morphological changes were observed by Oil red O staining. Real-time fluorescence quantitative PCR, Western blot and immunoprecipitation were used to detect gene and protein expression in liver. Results: RCR (50 mg/kg) reversed liquid fructose-induced increase in hepatic triglyceride content in rats. Attenuation of the increased vacuolization and Oil Red O staining area was evident on histological examination of liver in RCR-treated rats. However, RCR treatment did not affect chow intake and body weight of rats. Although some genes of the pathways involved in DNL (ChREBP, SREBP-1c, FAS, ACC1, SCD1, DGAT1, DGAT2 and MGAT2), fatty acid β-oxidation (PPARα, CPT1a, ACO and FGF21), VLDL-export (MTTP) and decomposition (HSL, ATGL) in the liver of fructose-fed rats were not changed significantly after RCR administration, the decrease in PPARα and PGC-1α proteins was reversed by RCR. Notably, SIRT1 mRNA and protein expression increased significantly with RCR administration. Furthermore, RCR increased expression of ATG4B, Beclin1 and decreased expression of Bcl2-Beclin1 complex dramatically. Meanwhile, RCR decreased the acetylation of beclin1. Moreover, RCR increased expression of autophagosome markers including LC3B and ATG5-ATG12-ATG16L1, and decreased expression of autophagolysosome marker p62 in the livers of fructose-fed rats. Conclusions: RCR has a certain improvement effect on fructose-induced hepatic steatosis, which is related to the activation of autophagy.

Six plant growth regulators frequently used in fruit were detected using UPLC–MS/MS including chlormequat chloride, GA3, forchlorfenuron, paclobutrazol, thidiazuron and 2,4-D. A modified QuEChERS method was used in pretreatment: each compound was extracted with acetonitrile containing 1% acetic acid and cleaned with a mixture of ostade-cylsilane (ODS) and MgSO4. The detection was performed using electrospray ionization (ESI) and multiple reaction monitoring mode (MRM) and quantified using the external standard method. Results indicated that the calibration curves of six plant growth regulators were linear within the range of 1–100 µg⋅kg-1 with correlation coefficients over 0.999. The recovery at four spiked concentrations, 1, 20, 50, and 100 µg⋅kg-1, ranged from 60.77% to 119.43% and relative standard deviation (RSD) were between 0.18% and 32.94%. The limits of detection (LOD) and limits of quantitation (LOQ) were 0.01–0.14 µg⋅kg-1 and 0.02–0.46 µg⋅kg-1, respectively, for apples, 0.01–0.18 µg⋅kg-1 and 0.03–0.59 µg⋅kg-1 for grapes, 0.01–0.08 µg⋅kg-1 and 0.04–0.28 µg⋅kg-1 for kiwis, 0.003–0.110 µg⋅kg-1 and 0.01–0.38 µg⋅kg-1 for peaches, and 0.01–0.08 µg⋅kg-1 and 0.03–0.25 µg⋅kg-1 for oranges.

Aiming at the problem of changing the distribution of overburden fissures in the overhead mining area due to the cutting and retaining roadway process, the stress distribution, overburden transport and mining fissure distribution law in the mining zone under the roof cutting and retaining roadway process were analyzed by means of a combination of physical similarity simulation and numerical simulation. On this basis, based on the key strata theory and the cumulative effect of unloading and expansion of mining overburden, the changes in the height of overburden fissure development and the width of fissure zones on the roof cutting and un-cutting sides were investigated, the extraction effect of the directional unloading gas extraction boreholes in different strata was analyzed, and the overburden fissure distribution law under the roof cutting and retaining roadway process was verified and inverted. The results shown that, the roof cutting and retaining roadway process can effectively reduce the stress concentration of the top and bottom plates on the roof cutting side, but the stress will still be transferred to the deeper part of coal. Roof cutting caused changes in the thickness of the collapsed rock layer and the form of roof breakage, which led to the changes in the height of the fissure zone development, and the width of the off-strata fissure zones within the sub-critical strata control range. The height of the collapsed zone on the roof cutting side was twice as much as that on the un-cutting side, and the height of the fissure zone was 0.87 times as much as that on the un-cutting side. In the middle and lower part of the fissure zone, the amount of off- strata and the number of penetrating fissures on the cut top side are larger than those on the uncut top side; the amount of fissure development on the roof cutting side were larger than those on the un-cutting side. The amount of fissure development on the coal seam roof of roof cutting side increased with the increasing distance in the range of 8−30 m, and decreased with the increasing distance in the range of 30−48 m, The fissures were mainly distributed in the middle and lower part of the fissure zone. The “staggered” gas concentration and flow rate of the extraction boreholes in different layers validated the above conclusions. The study results have certain reference value for the decompression gas management in high gas mines under the process of roof cutting and retaining roadway.

In order to further clarify the influence of multistage pulse ultrasound on the characteristics of gas desorption in water-bearing coal, the ultrasonic stimulation test system of gas-containing coal is used to analyze the pore structure and gas desorption of coal under the condition of continuous ultrasonic stimulation of coal with different moisture contents and multistage pulse stimulation of water-saturated coal, and the mechanism of multistage pulse stimulation of water-bearing coal is revealed. The results show that the average pore diameter, specific surface area and total pore volume of coal increase with the increase of ultrasonic power and water saturation degree. When ultrasonic power is 1000 W, compared with dry coal, the increase of specific surface area and total pore volume of coal increases from 4.369% and 3.504% of 25% moisture content to 7.699% and 8.992% of 100% moisture content, respectively. There is a Langmuir-type relationship between coal gas desorption and time, and coal gas desorption amount and desorption rate are positively correlated with ultrasonic power and water saturation degree of coal. Compared with dry coal, the gas desorption capacity and desorption rate increase linearly with the increase of water saturation degree of coal, and ultrasonic stimulation has the best effect on the pore reconstruction and gas desorption of water saturated coal. With the increase of ultrasonic multistage pulse times, the specific surface area, total pore volume, gas desorption capacity and desorption rate of water-saturated coal increase. Compared with the 1000 W ultrasonic excitation, the increase of specific surface area and total pore volume of coal is a positive power function of the number of multistage pulses. The increase of gas desorption amount and desorption rate of coal increases from 2.745% and 4.598% of the first multistage pulse to 27.222% and 11.106% of the third multistage pulse, respectively, which is in a positive linear relationship with the number of multistage pulses. The combined effect of vibration and cavitation generated by multi-stage pulse ultrasonic stimulation of water-bearing coal causes fatigue damage to the coal matrix, strengthens the pore transformation of coal, and increases the molecular kinetic energy of gas, thus promoting gas desorption in coal. On site, the gas extraction in coal seam can be enhanced through the development of multi-stage pulse ultrasonic emitter combined with hydraulic technology.

In order to study the evolution law of gas transportation and storage area under different advancing speed of fully-mechanized working face, based on the overview of coal mine project, we analyzed the effect of overburden mining advancing speed by using FLAC3D numerical software for simulation, and used various methods to jointly discriminate the unloading gas transportation and storage area, obtained the distribution and evolution law of unloading gas transportation and storage area under different advancing speed conditions. Based on this, we optimized the high level extraction drilling in the field. The results show that after the coal seam mining in the fully mechanized mining face, the vertical stress distribution roughly follows a symmetrical trapezoidal shape, and the advancing speed is accelerated. The vertical stress distribution changes into a left high right low throw line; the subsidence amount and plastic failure height of the overlying rock in the goaf decrease with the increase of advancing speed; the height of the unloading gas storage area decreases with the increase of the advancing speed, and the location of the unloading gas storage area is concentrated towards the middle of the goaf; after optimizing the pressure relief gas extraction drilling holes in the experimental working face, the maximum gas volume fraction of the extraction drilling holes in the high and low advancing speed areas of the experimental working face is above 30%. The gas volume fractions in the working face, return air roadway, and upper corner are 0.18%-0.46%, 0.2%-0.46%, and 0.25%-0.84%, all less than 1%, making the layout method more reasonable.

As an important negative carbon technology to solve the carbon emission problem in the coal industry, the CO2 sequestration in the mine goaf has a wide application prospect in the secondary utilization of waste resources in the goaf and the capture and storage of CO2. In this study, the influence of different temperatures and pressures, formation water salinity and cationic solution type on the interfacial tension (IFT) of CO2-formation water system was investigated by using in-situ interfacial tension meter. The gas-liquid interface diffusion effect of CO2 injection into water-bearing coal rock mass was clarified. The equation of state (SAFT-LJ equation of state) based on statistical association theory combined with the Lanner-Jones potential energy model and density gradient theory (DGT) were combined to predict the theoretical value of IFT. Using a self-developed geological sequestration and geochemical reaction simulation experimental platform, various exploratory experiments were conducted to investigate the solubility of CO2 under the same conditions. The characteristics of CO2 solubility variation in the reservoir environment of the goaf were obtained, and the corresponding theoretical values of CO2 solubility were calculated using the D-S model. The experimental results show that when the ambient temperature is constant, the reservoir pressure in the goaf is linearly negatively correlated with the IFT value. As the reservoir temperature increases, the IFT value increases correspondingly, but the change range is small. Under constant temperature and pressure conditions, there is a positive correlation between salinity and IFT value. Within the scope of this experiment, low pressure, high temperature, and high salinity promote an increase in the IFT value. The IFT values between CO2-salt solutions show an increasing trend with the increasing valence of cations (K+ < Na+ < Ca2+ < Mg2+). The pressure of the depleted reservoir is positively correlated with the CO2 solubility. When the temperature is 25 °C and under conditions of pure water, as the pressure increases from 0.5 MPa to 2.5 MPa, the corresponding CO2 solubility increases from 0.1627 mol/kg to 0.7141 mol/kg. The CO2 solubility decreases with the increases of temperature and salinity. Under the same concentration, monovalent cation solutions (NaCl, KCl) can dissolve more CO2 than divalent cation solutions (CaCl2, MgCl2). The free phase CO2 injected into the goaf overcomes the interfacial tension and breaks the geochemical balance of the goaf strata through diffusion and dissolution mass transfer. By clarifying the influence of reservoir temperature and pressure conditions and goaf water environment on IFT value and CO2 solubility, the gas-liquid interface effect and dissolution mass transfer mechanism of CO2-formation water are clarified, so as to provide a theoretical basis for the safety and evaluation of CO2 sequestration in the closed mine goaf.

Many factors combine to influence the spatial distribution characteristics of overburden fracture during the increasingly intense mining process in coal mines. The characteristics of overburden fracture distribution has important significance in guiding the gas management in liberated layer mining. Several sets of two-dimensional physical similarity simulation experiments were carried out to investigated the distribution characteristics of overburden fracture network and the property parameters of the pressure relief gas storage and migration channels under different mining conditions (mining height, advancement speed, key layer upon layer and coal seam inclination). The topological network with geometric and fissure parameters was obtained. The topological transformation of the real stem system was simplified based on the theory of complex network evolution, and the evolution characteristics of the stem system structure and factor nodes of the transportation and storage channel was analyzed combined with the complex network characteristic parameters. The influencing factors of the overburden fissure network stem system was quantitatively described, and a matrix and model of the network structure of pressure relief gas transport and storage channel were established. The results indicated that, the development range, through degree, and fractal dimension of pressure relief gas migration and storge channel expand with the increase of mining height, key layer position, and coal seam dip angle. However, the development range shown a decreasing trend with the acceleration of advancing speed. The increase in mining height had the greatest impact on the amount of separation, with a 146.9% increase at 6 m mining height compared to 4 m. The variation in fracture density was mainly influenced by the dip angle of the coal seam, and was less influenced by the advancing speed. Arranging the boreholes in high-density areas (density > 4.7 pieces/m) can effectively act as a gas retention. The research results can further optimize the arrangement parameters of gas extraction boreholes under the influence of different factors, improve the efficiency of gas extraction, so as to ensure the safe and efficient recovery of the working face, which is of certain practical significance for the realization of accurate and green gas extraction.