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Over the past decades, unmanned aerial vehicles (UAVs) have been widely used in both military and civilian fields. In these applications, flocking motion is a fundamental but crucial operation of multi-UAV systems. Traditional flocking motion methods usually designed for a specific environment. However, the real environment is mostly unknown and stochastic, which greatly reduces the practicality of these methods. In this paper, deep reinforcement learning (DRL) is used to realize the flocking motion of multi-UAV systems. Considering that the sim-to-real problem restricts the application of DRL to the flocking motion scenario, a digital twin (DT) enabled DRL training framework is proposed to solve this problem. The DRL model can learn from DT and be quickly deployed on the real-world UAV with the help of DT. Under this training framework, this paper proposes an actor-critic DRL algorithm named behavior-coupling deep deterministic policy gradient (BCDDPG) for the flocking motion problem, which is inspired by the flocking behavior of animals. Extensive simulations are conducted to evaluate the performance of BCDDPG. Simulation results show that BCDDPG achieves a higher average reward and performs better in terms of arrival rate and collision rate compared with existing methods.

Natural soil has the ability to suppress the soil-borne pathogen to a certain extent, and the assemblage of soil microbiome plays a crucial role in maintaining such ability. Long-term monoculture accelerates the forms of soil microbiome and leads to either disease conducive or suppressive soils. Here, we explored the impact of soil conditions on bacterial wilt disease (healthy or diseased) under long-term tobacco monoculture on the assemblage of bacterial and fungal communities in bulk and rhizosphere soils during the growth periods. With Illumina sequencing, we compared the bacterial and fungal composition of soil samples from tobacco bacterial wilt diseased fields and healthy fields in three growth periods. We found thatProteobacteriaandAscomycotawere the most abundant phylum for bacteria and fungi, respectively. Factors of soil conditions and tobacco growth periods can significantly influence the microbial composition in bulk soil samples, while the factor of soil conditions mainly determined the microbial composition in rhizosphere soil samples. Next, rhizosphere samples were further analyzed with LEfSe to determine the discriminative taxa affected by the factor of soil conditions. For bacteria, the genusRalstoniawas found in the diseased soils, whereas the genusFlavobacteriumwas the only shared taxon in healthy soils; for fungi, the genusChaetomiumwas the most significant taxon in healthy soils. Besides, network analysis confirmed that the topologies of networks of healthy soils were higher than that of diseased soils. Together, our results suggest that microbial assemblage in the rhizosphere will be largely affected by soil conditions especially after long-term monoculture.

Growth promotion and stress tolerance induced by endophytes have been observed in various plants, but their effects on mulberry regularly suffering flood in the hydro-fluctuation belt are less understood. In the present study, endophytic

Plant growth-promoting rhizobacteria have been shown to play important roles in maintaining host fitness under periods of abiotic stress, and yet their effect on mulberry trees which regularly suffer drought after flooding in the hydro-fluctuation belt of the Three Gorges Reservoir Region in China remains largely uncharacterized. In the present study, 74 bacterial isolates were obtained from the rhizosphere soil of mulberry after drought stress, including 12 phosphate-solubilizing and 10 indole-3-acetic-acid-producing isolates. Bacillus megaterium HGS7 was selected for further study due to the abundance of traits that might benefit plants. Genomic analysis revealed that strain HGS7 possessed multiple genes that contributed to plant growth promotion, stress tolerance enhancement, and antimicrobial compound production. B. megaterium HGS7 consistently exhibited antagonistic activity against phytopathogens and strong tolerance to abiotic stress in vitro. Moreover, this strain stimulated mulberry seed germination and seedling growth. It may also induce the production of proline and antioxidant enzymes in mulberry trees to enhance drought tolerance and accelerate growth recovery after drought stress. The knowledge of the interactions between rhizobacteria HGS7 and its host plant might provide a potential strategy to enhance the drought tolerance of mulberry trees in a hydro-fluctuation belt.

Bacterial wilt, caused by the plant pathogen Ralstonia solanacearum, occurs more severely in acidified soil according to previous reports. However, R. solanacearum cannot grow well in acidic environments under barren nutrient culture conditions, especially when the pH is lower than 5. With the worsening acidification of farmland, further determination of how R. solanacearum adapts to the long-term acidic environment is worthwhile. In this study, experimental evolution was applied to evaluate the adaptability and mechanism of the R. solanacearum experimental population responding to long-term acid stress. We chose the CQPS-1 strain as the ancestor, and minimal medium (MM medium) with different pH values as the culture environment to simulate poor soil. After 1500 generations of serial passage experiments in pH 4.9 MM, acid-adapted experimental strains (denoted as C49 strains) were obtained, showing significantly higher growth rates than the growth rates of control experimental strains (serial passage experiment in pH 6.5 MM, denoted as C65 strains). Competition experiments showed that the competitive indices (CIs) of all selected clones from C49 strains were superior to the ancestor in acidic environment competitiveness. Based on the genome variation analysis and functional verification, we confirmed that loss of function in the phcA gene was associated with the acid fitness gain of R. solanacearum, which meant that the inactivation of the PhcA regulator caused by gene mutation mediated the population expansion of R. solanacearum when growing in an acidic stress environment. Moreover, the swimming motility of acid evolution strains and the phcA deletion mutant was significantly enhanced compared to CQPS-1. This work provided evidence for understanding the adaptive strategy of R. solanacearum to the long-term acidic environment.

In recent years, the low sensitivity caused by plasma quenching has restricted the development of LIBS technology in practical applications. In order to improve the sensitivity of the LIBS analysis method, we proposed a nanoparticle-assisted metal–organic framework (MOF) enhanced laser-induced breakdown spectroscopy, which combines a metal–organic framework (MOF), Au nanoparticles (AuNPs), and a portable LIBS instrument. Common metal ions in water were selected as the research objects to be tested by the proposed method. First, the synthesized three-dimensional (3D) MOF, namely [Zn2(L2)]2DMA·3H2O (complex 1) [H2L = 2-(imidazole-1-yl)terephthalic acid], was used to capture metal ions. Second, complex 1 loaded with metal ions induced AuNPs to aggregate on its surface. Third, the samples were attached to the glass substrate with double-sided tape and analyzed by LIBS. As a result, the limits of detection (LODs) for Pb and Cr obtained in this work were 8.0 and 4.2 ng mL−1, respectively, which were notably 8–10 times lower than those of the complex 1 enrichment method alone and 4 orders of magnitude lower than those of traditional LIBS methods. The significant improvement in LODs was also a new breakthrough for LIBS in liquid analysis. The great improvement in sensitivity can be mainly attributed to the unique microporous structure and the exposed metal binding sites of complex 1, which provide a huge space to accommodate metal ions. Also, the coupling action between laser electromagnetic fields and the surface plasmon of AuNPs greatly improved the laser ablation efficiency in the process of laser–matter interaction. Finally, the analysis of actual samples yielded good recoveries (92.8–99.0%) and reproducibility (lower than 11.9%), which shows the great potential of the combination of this method and portable LIBS in-field detection.

This study has identified two polymer additives that when added in low concentrations can be used to reliably prevent incongruent melting of sodium acetate trihydrate (SAT) when temperature-cycled over multiple thousands of melting and freezing cycles. The polymers appear to act as crystal-habit modifiers that at sub-optimal concentrations dramatically alter the morphology of any anhydrous sodium acetate that may be formed, and at higher concentrations completely suppress precipitation of anhydrous sodium acetate. In situ X-ray powder diffraction experiments show that the active nucleator for SAT is Na2HPO4·2H2O, and that the mechanism of thermally induced deactivation is dehydration in solution to form anhydrous Na2HPO4. Based on these studies, new formulations of SAT have been developed that demonstrate consistent and reliable performance as phase-change materials for heat-storage applications.

The cause of some patients with negative RT-PCR results experienced turn-positive after treatment remains unclear. In addition, understanding the correlation between changes in clinical data in the course of COVID-19 and treatment outcomes is of great importance in determining the prognosis of COVID-19. To perform cause analysis of RT-PCR turn-positive and the effective screening factors related to treatment outcome in COVID-19. Clinical data, including clinical manifestations, laboratory tests, radiography results, treatment methods and outcomes, were retrospectively collected and analyzed from January to March 2020 in Renmin Hospitals of Wuhan University. 116 COVID-19 patients (40 in recurrent group, 29 in recovered group and 47 in unrecovered group) were recruited. In the recurrent group, white blood cell, Neutrophils, prothrombin time, activated partial thromboplastin time, CD3, CD4, CD8, ratio of CD4/CD8, IgG and C4 complement were of significant difference among the baseline, negative and turn-positive time points. CD19 and CT scan results were found notable difference between recurrent group and recovered group. Odds from CD3, CD4, CD8, CD19, IgM, C3 complement, C4 complement and CT scan results validated associations with clinical outcomes of COVID-19. The so-called recurrence in some COVID-19 patients may be due to the false-negative of nucleic acid test results from nasopharyngeal swabs. Levels of CD3, CD4, CD8, CD19, IgM, C3 complement, C4 complement and CT results were significantly correlated with the outcome of COVID-19. The cellular immunity test could be beneficial to further screen the reliability of RT-PCR test on the basis of CT images.

Background Mycotoxins have received much attention due to their potential harmful impact on humans. Increasing awareness of environmental protection and food safety prompts the use of eco-friendly and biosafe strategies for mycotoxin elimination in food production. Scope and approach Mycotoxin adsorption by microorganisms has become increasingly promising due to its environmental friendliness and efficiency. This review is mainly focused on discussing different kinds of microorganisms able to adsorb mycotoxins, exploring the main mechanisms of yeast and lactic acid bacterial bioadsorption actions involving cell wall physical structure, chemical components, and their complicated interactions with mycotoxins. Moreover, industrial applications and future research needs are also proposed. Key findings and conclusions Yeasts and lactic acid bacteria have the great advantages of their adsorption capability and being food security friendly, and their complicated interactions with mycotoxins indicate that cell wall structural integrity, physical structure and morphology, and chemical components all play important roles in the adsorption process. On this basis, future approaches may rely on combinations of different microorganism to provide complementary advantages in mycotoxin degradation and adsorption.

Bacterial wilt is accompanied by microbial communities shift and soil acidification. However, the relationship between the changes of bacterial communities and bacterial wilt under the influence of different acidification levels has not been fully elucidated. Here, we analyzed the abundance of Ralstonia solanacearum, rhizosphere bacterial communities and carbon metabolism at differently acidic levels (pH 6.45, pH 5.60, pH 5.35, pH 4.90 and pH 4.45) and soil amendment treatment (CaO). The results indicated that both the abundance of R. solanacearum and the incidence of bacterial wilt showed a significant trend of first increasing and then decreasing with the increase of soil pH. The Firmicutes phylum and potentially beneficial genera

Plant growth-promoting rhizobacteria have been shown to play important roles in maintaining host fitness under periods of abiotic stress, and yet their effect on mulberry trees which regularly suffer drought after flooding in the hydro-fluctuation belt of the Three Gorges Reservoir Region in China remains largely uncharacterized. In the present study, 74 bacterial isolates were obtained from the rhizosphere soil of mulberry after drought stress, including 12 phosphate-solubilizing and 10 indole-3-acetic-acid-producing isolates.

Drought stress often leads to heavy losses in mulberry planting, especially for fruits and leaves. Application of plant growth-promoting fungi (PGPF) endows various plant beneficial traits to overcome adverse environmental conditions, but little is known about the effects on mulberry under drought stress. In the present study, we isolated 64 fungi from well-growing mulberry trees surviving periodical drought stress, and Talaromyces sp. GS1, Pseudeurotium sp. GRs12, Penicillium sp. GR19, and Trichoderma sp. GR21 were screened out due to their strong potential in plant growth promotion. Co-cultivation assay revealed that PGPF stimulated mulberry growth, exhibiting increased biomass and length of stems and roots. Exogenous application of PGPF could alter fungal community structures in the rhizosphere soils, wherein Talaromyces was obviously enhanced after inoculation of Talaromyces sp. GS1, and Peziza was increased in the other treatments. Moreover, PGPF could promote iron and phosphorus absorption of mulberry as well. Additionally, the mixed suspensions of PGPF induced the production of catalase, soluble sugar, and chlorophyll, which in turn enhanced the drought tolerance of mulberry and accelerated their growth recovery after drought. Collectively, these findings might provide new insights into improving mulberry drought tolerance and further boosting mulberry fruit yields by exploiting interactions between hosts and PGPF.

The effects of global warming have warmed the climate of the Qinghai-Tibetan Plateau (QTP) leading to changes in plant growth and soil nutrients in the alpine meadows. However, few studies have addressed the effects of warming on plant allometric growth and soil stoichiometry in these meadows on a long-term scale. Therefore, the effects of soil stoichiometry on plant allometric growth remain unclear under long-term warming in the alpine meadows. This study adopted infrared radiators to conduct an 8-year warming experiment in a permafrost region on the QTP starting in 2010, and surveyed growth indices of the plant community during the growing season. Soil organic carbon (C), total nitrogen (N), and total phosphorus (P) in an alpine meadow were measured. We initially learned that the aboveground part of the alpine meadow vegetation in the warming treatment changed from an isometric to an allometric growth pattern while the allometric growth pattern of the belowground part was further strengthened. Second, the contents of soil C, N, and P decreased at the 0–20 cm depth and increased at the 20–30 cm depth in warming. The ratios of soil C:N, C:P, and N:P showed increasing trends at different soil depths with artificial warming, and their amplitudes increased with soil depths. Warming promoted the migration of soil stoichiometric characteristics of C, N, and P to deep soil. Finally, the correlations of plant growth with soil stoichiometric characteristics were weakened by warming, demonstrating that the downward migration of soil stoichiometric characteristics to deep soil in warming had effects on the growth of vegetation in the alpine meadow. It concludes that the change in soil stoichiometric characteristics with soil depths promotes plant allometric growth in the alpine meadow under climate warming.

Bacterial wilt, caused by the plant pathogen

Rapid detection and efficient removal of heavy metal ions from environmental water are of considerable importance to tackle the water pollution problem. In this work, a simple but efficient strategy named metal-chelate induced nanoparticle aggregation enhanced laser-induced breakdown spectroscopy (MINAELIBS) was proposed for signal enhancement aiming at ultra-sensitive detection of trace levels of metal elements in liquid samples. Unlike the surface contact approach previously reported in the literature, direct mixing of gold nanoparticles (AuNPs) and metal chelates increased the contact area, adhesion force, and uniformity between analytes and AuNPs. As a result, under the optimal conditions, the limits of detection (LODs) of Cd, Cu, Ag, Pb, and Cr were 4.6, 1.5, 3.4, 3.5, and 3.5 ng mL−1, respectively. The LODs of target elements were notably 7–10 times lower than those of chelating reagent enrichment alone and 3–4 orders of magnitude lower compared to traditional LIBS methods, which demonstrates the feasibility of MINAELIBS in analysis of liquid samples at the ppb level. Application of AuNPs for high-performance signal enhancement has undoubtedly pushed the method sensitivity of traditional LIBS analyses to a new level. In addition, the recoveries of all the analytical elements in the environmental water samples were in the range from 88.6% to 109.9%, which further proves the feasibility and potential of MINAELIBS in practical liquid sample analysis.

We report the unexpected pressure-induced and time-dependent nucleation and crystallisation of n-pentane from a 1 : 1 mixture of n-pentane and iso-pentane. The crystal structure of n-pentane at 3.3 GPa is reported; the 19.6% decrease in volume up to 3.3 GPa is caused by the significant reduction of voids within the structure. The study has wider implications for the separation of mixtures of organic compounds that have similar melting and boiling points, as well as the use of a 1 : 1 mixture of n-pentane and iso-pentane as a pressure-transmitting medium in high-pressure diffraction experiments.

Microbial competition for carbon sources is associated with disease suppression, and continuous mono-cropping stimulates certain patterns of carbon deposits. In this study, we investigated five fields from three ginger mono-cropping durations (over 35 years, approximately 15 years and 3 years) and two disease conditions (wilt-suppressive and wilt-conducive) at two collection time points (fallow and harvest). We measured the bacterial community and overall microbial carbon metabolism ability using high-throughput sequencing and Biolog EcoPlates. The results showed that the metabolic capabilities of soil microbes at harvest time were higher than at fallow time. The distribution of the bacterial community and the soil microbial metabolic diversity were significantly affected by both factors of cropping years and disease conditions at harvest time. Moreover, potentially beneficial microbes more enriched in wilt-suppressive soils than in wilt-conducive soils and l -arginine and 4-hydroxybenzoic acid were significantly metabolized in suppressive samples. We further confirmed that l -arginine and 4-hydroxybenzoic acid were only slightly metabolized by the pathogen. Taken together, these results suggest that the addition of l -arginine could enrich the beneficial microbes, while metabolism of 4-hydroxybenzoic acid could indicate the disease conditions of soil.

Variable-temperature single-crystal and powder X-ray diffraction techniques have been used to study the thermal and mechanical decomposition of the acetonitrile solvate of the cocrystal formed betw...

Surface molecularly imprinted polymer of solanesol (SA-SMIP) was prepared by reversed phase suspension polymerization using modified titanium dioxide (TiO2) as carrier, and operation conditions were investigated and optimized. Structures of modified TiO2 and SA-SMIP obtained at optimal conditions were characterized by Fourier transform infrared spectrometer adopting original TiO2 and non-surface molecularly imprinted polymer as reference. The SA-SMIP synthesized under optimal conditions displayed an excellent recognition of SA from the mixture of SA and triacontanol. The maximum separation degree of SA was 2.90. Finally, the adsorption kinetics and isotherm were investigated and analyzed. Adsorption kinetics results indicated that the adsorption of SA-SMIP to SA was a pseudo-second order process, and the adsorption of beginning and later stages was controlled by homogeneous particle diffusion and adsorption reaction process, respectively. Adsorption isotherm results documented hereby were two sorts of bonding sites, complete imprinted cavities and defective imprinted cavities. The adsorption for two bonding sites could be well lined up with the Langmuir model.

Based on snow-depth and measured runoff data in the 19 river basins of the cryosphere areas of China, changes in cold season snow depth (CSSD) and spring runoff, and the relationship between CSSD a...

The classical conclusions about the vehicle stability are usually drawn from the 2-DOF vehicle model. As more and more researchers begin to explore the complex dynamic characteristics of nonlinear and high degrees of freedom vehicle plane motion system, it is of value to intuitively reveal the global dynamic characteristics by objective quantitative indicators. Moreover, a new quantitative indicator, dissipation of energy, was proposed in 2021, and it is also worth further analyzing its rationality. For the above purposes, first of all, this paper briefly introduces the difference between the 2-DOF model and the high degree of freedom (≥3) model based on previous work. Secondly, this paper objectively discusses the stability characteristics of high degrees of freedom vehicle system from different aspects (dissipation of energy, longitudinal velocity, tire sideslip angle, convergence time) for the first time. In addition, the relationship between each indicator is systematically compared with the dissipation of energy, and their advantages and disadvantages are explained. Therefore, the main contributions of this paper are as follows: (1) This paper supplements previous conclusions on the dynamic characteristics of high-DOF vehicle plane motion system and helps researchers better understand the global dynamic characteristics from different perspectives. (2) This paper supplements previous discussions on the rationality and effectiveness of dissipation of energy method, and objectively reveals the relationship between dissipation of energy and stability. (3) This paper establishes a link between qualitative and quantitative methods. The vehicle system dynamics characteristics are presented from a variety of quantitative perspectives for the first time, supplementing the relevant research in the field of dynamics quantitative indicators.

Single crystals which exhibit mechanical flexibility are promising materials for advanced technological applications. Before such materials can be used, detailed understanding of the mechanisms and structural effects of bending are needed. Coordination polymer single crystal represent a fascinating class of mechanically flexible material; their bending contradicts existing models. Using single crystal X-ray diffraction and microfocus Raman spectroscopy, we study in atomic detail the high-pressure response of the plastically flexible coordination polymer [Zn(μ‐Cl)2(3,5‐dichloropyridine)2]n. In stark contrast to three-point bending, the quasi-hydrostatic compression of the single crystal is completely reversible, even following compression to over 9 GPa. A structural phase transition is observed at ca. 5 GPa. Ab initio DFT calculations show this transition to result from the pressure-induced softening of low frequency vibrations. This phase transition is not observed during three-point bending. Our combined experimental and theoretical high-pressure investigation propose slight compression at low levels of bending. However, our studies provide the first indication of overall disparate mechanical responses of bulk flexibility and quasi-hydrostatic compression. We suspect this to be a general feature of mechanically plastic materials.

The widespread use of biodiesel as a renewable fuel offers many potential advantages, but at the same time presents challenges for modern internal combustion engines, particularly for those that involve high-pressure injection of fuel into the combustion chamber. At the typical elevated pressures used in such engines, biodiesel can crystallise and block fuel filters and injection nozzles, thereby causing engine failure. In this study, optical studies and Raman spectroscopy of a typical biodiesel sample contained in a diamond-anvil cell show that biodiesel initially crystallises at ca. 0.2 GPa and then undergoes a series of structural changes on further increase of pressure. On account of the complex composition of biodiesel, this study focused on one of its main components – methyl stearate. Using a combination of Raman spectroscopy, X-ray powder diffraction and neutron powder diffraction, it was shown that methyl stearate exhibits rich polymorphic behaviour when subjected to elevated pressures up to 6.3 GPa. Under non-hydrostatic conditions, pressures as low as 0.1 GPa converted Form V to crystallites of Form III that typically adopt plate-like morphologies. This observation has implications for the pressure-induced crystallisation of biodiesel containing high proportions of methyl stearate because of the potentially serious consequences for blocking of injection nozzles in engines. Four phase transitions over the pressure range of 0.1 GPa to 6.3 GPa were also observed. Form III was recovered on decompression to ambient pressure. High-pressure neutron powder diffraction studies of a perdeuterated sample showed that Form V persisted up to 3.11 GPa. This contrast in behaviour between the X-ray and neutron studies may be a consequence of deuteration, or of compression under non-hydrostatic versus hydrostatic conditions.

The near-surface soil freeze state is affected by global warming, and its changes have profound effects on landscapes, ecosystems and hydrological processes. On the basis of daily soil freeze observational data at 476 meteorological stations over 50 freezing years from September 1, 1961 to August 31, 2011, the spatial distributions and temporal variations of the near-surface soil freeze state were estimated using five freeze variables (first date, last date, maximum seasonally frozen depth, duration and actual number of freeze days) across China, which was divided into three regions (eastern China, northwestern China and the Qinghai-Tibetan Plateau (QTP)). The near-surface soil freeze state varied greatly across China. The QTP has an earlier freeze, later thaw, longer freeze days and deeper seasonally frozen depth than the other two regions. The spatial distributions of the near-surface soil freeze state can be explained largely by altitude in northwestern China and on the QTP, whereas they can be explained by latitude in eastern China. The near-surface soil freeze state has changed significantly over 50 freezing years. On average across China over the study period, the first date of freezing was delayed by approximately 10 ± 1 days with a rate of 0.20 ± 0.02 days/year, the last date advanced by approximately 18 ± 2 days with a rate of 0.36 ± 0.04 days/year, the duration and the number of freeze days decreased by 28 ± 2 and 23 ± 2 days with rates of 0.56 ± 0.04 and 0.45 ± 0.04 days/year, respectively, and the maximum seasonally frozen depth decreased by 20 ± 3 cm with a rate of 0.41 ± 0.06 cm/year. The change in the freeze variables is relatively large in high-latitude and high-altitude regions.

The equation of state, dynamical properties, and molecular-scale structure of squalane and mixtures of poly-α-olefins at room temperature are studied with a combination of state-of-the-art, high-pressure experiments and molecular-dynamics simulations. Diamond-anvil cell experiments indicate that both materials are non-hydrostatic media at pressures above ∼1 GPa. The equation of state does not exhibit any sign of a first-order phase transition. High-pressure x-ray diffraction experiments on squalane show that there are no Bragg peaks, and hence, the apparent solidification occurs without crystallization. These observations are complemented by a survey of the equation of state and dynamical properties using simulations. The results show that molecular diffusion is essentially arrested above about 1 GPa, which supports the hypothesis that the samples are kinetically trapped in metastable amorphous-solid states. The shear viscosity becomes extremely large at very high pressures, and the coefficient governing its increase from ambient pressure is in good agreement with the available literature data. Finally, simulated radial distribution functions are used to explore the evolution of the molecular-scale structure with increasing pressure. Subtle changes in the short-range real-space correlations are related to a collapse of the molecular conformations with increasing pressure, while the evolution of the static structure factor shows excellent correlation with the available x-ray diffraction data. These results are of indirect relevance to oil-based lubricants, as the pressures involved are comparable to those found in engines, and hence, the ability of lubricating thin films to act as load-bearing media can be linked to the solidification phenomena studied in this work.

In this study, heat and relative humidity (HRH) treatment was applied in highland barley for γ-aminobutyric acid (GABA) accumulation. Tibetan highland barley cultivars (25) were selected for comparison and analysis. HRH treatment could accumulate GABA in several hours with low moisture content and high temperature, and the grains were treated for 2.5 h at 65 °C in this study. The GABA content of processed grains under HRH optimal condition ranged from 26.91 to 76.28 mg·100 g−1, which was significantly higher than the initial content (12.78–43.00 mg·100 g−1). The highest GABA accumulation capacity was observed in two-row yellow cultivars (YT1), increasing from 36.52 to 76.28 mg·100 g−1. Correlation analysis showed that the accumulation of GABA after HRH treatment was positively and significantly (p < 0.05) correlated with the contents of protein (0.52), total free amino acids (0.68), threonine (0.53), serine (0.51), glutamate (0.69), glycine (0.49), alanine (0.46), cysteine (0.57), tyrosine (0.50), lysine (0.53), proline (0.40), and glutamate decarboxylase (GAD) activity (0.62), which were closely related to GABA-shunt pathway. The polyamines contents, diamine oxidase (DAO) and polyamine oxidase (PAO) activities, as the substrates and critical enzymes of polyamine degradation pathway, showed no significant correlation with GABA accumulation. The results suggested that the main pathway of GABA accumulation in highland barley under HRH treatment was GABA-shunt pathway.

The increase in low flows (winter discharge and minimum monthly discharge), caused primarily by permafrost degradation, is common in high‐latitude permafrost regions, whereas the dynamics of low flows in high‐altitude permafrost regions remain largely unknown. Long‐term discharge data from 28 unregulated catchments in western China were analysed, and the findings showed that winter discharge/minimum monthly discharge significantly increased (p ≤ 0.1) in 82/82%, 55/64%, and 0/0% of the catchments in the higher‐latitude mountain permafrost regions (Tienshan Mountains), mid‐latitude mountain permafrost regions (Qilian Mountains), and mid‐ to low‐latitude plateau permafrost regions (the source regions of the Yangtze and Yellow rivers), respectively. The differences in permafrost type and the distribution of permafrost and alpine cold desert (which is similar to tundra) were found to be the main causes for the different responses in the low flows. The rate of change of low flows (winter discharge and minimum monthly discharge) was negatively and linearly correlated with permafrost coverage when coverage was less than 40% of the catchment area, whereas the low flows changed only slightly when the permafrost coverage exceeded 40%. A significant thickening of the active layer increased the low flows in the lower permafrost‐covered catchments, which are dominated by warm permafrost. However, in the higher permafrost‐covered catchments with cold permafrost and a cold climate, only an increase in permafrost temperature (without a notable thickening of the active layer) occurred, resulting in non‐significant changes in low flows.

With the popularity of the automatic precipitation gauges in national weather stations, testing their performance and adjusting their measurements are top priorities. Additionally, because different climatic conditions may have different effects on the performance of the precipitation gauges, it is also necessary to test the gauges in different areas. This study mainly analyzed precipitation measurements from the single-Alter-shielded TRwS204 automatic weighing gauge (TRwSSA) relative to the adjusted manual measurements (reference precipitation) from the Chinese standard precipitation gauge in a double-fence wind shield (CSPGDF) in the Hulu watershed in the Qilian Mountains, China. The measurements were compared over the period from August 2014 to July 2017, and the transfer function derived from the work by Kochendorfer et al. (2017a) for correcting wind-induced losses was applied to the TRwSSA measurements. The results show that the average loss of TRwSSA measurements relative to the reference precipitation decreased from 0.55 mm (10.7%) to 0.51 mm (9.9%) for rainfall events, from 0.35 mm (8.5%) to 0.22 mm (5.3%) for sleet events, and from 0.49 mm (18.9%) to 0.33 mm (12.7%) for snowfall events after adjustment. The uncorrected large biases of TRwSSA measurements are considered to be mainly caused by specific errors of TRwSSA, different gauge orifice area and random errors. These types of errors must be considered when comparing precipitation measurements for different gauge types, especially in the mountains.

To study the influence of the preparation method on Cu active sites and the reaction pathway in NO reduction by NH3 over Cu–SSZ-13, three kinds of catalysts (Cu ion-exchanged SSZ-131, one-pot synthesis Cu–SSZ-132, and Ce0.017–Fe0.017/Cu–SSZ-13 [Ce and Fe ion exchange on the basis of Cu–SSZ-132]) were prepared. In situ diffuse reflectance infrared Fourier transform spectroscopy and H2 temperature program reduction were used to study the differences in the reaction pathways and Cu active sites over the three kinds of catalysts. Density functional theory was employed to study the effect of active sites on the reaction pathway. In situ DRIFTS showed that the reaction pathway on Cu–SSZ-131 during NO oxidation was different from that on Cu–SSZ-132 and Ce0.017–Fe0.017/Cu–SSZ-13. The difference was that intermediate NO2 was involved in the selective catalytic reduction reaction on Cu–SSZ-131, whereas NO2 was not found during the reaction process on Cu–SSZ-132 and Ce0.017–Fe0.017/Cu–SSZ-13. H2–TPR studies revealed that the three catalysts had different Cu active sites, which were located in the six-membered ring, eight-membered ring, and CHA cage. On the basis of DFT studies, NO and O2 were more conducive to form nitrate when the Cu species was on the six- and eight-membered rings; by contrast, NO and O2 were more conducive to form NO2 in the cage. These results showed that different preparation methods led to various Cu active sites, and varying Cu active sites could lead to different NO oxidation processes.

Application of soil amendments has been wildly used to increase soil pH and control bacterial wilt. However, little is known about causal shifts in the rhizosphere microbial community of crops, especially when the field naturally harbors the disease of bacterial wilt to tobacco for many years due to long-term continuous cropping and soil acidification. In this study, biochar (CP), lime (LM), oyster shell powder (OS) and no soil amendment additions (Control; CK) were assessed for their abilities to improve the soil acidification, change the composition of rhizosphere soil bacterial communities and thus control tobacco bacterial wilt. The results showed that oyster shell powder significantly increased soil pH by 0.77 and reduced the incidence of tobacco bacterial wilt by 36.67% compared to the control. The Illumina sequencing -based community analysis showed that soil amendment applications affected the composition of rhizosphere bacterial community and increased the richness and diversity. In contrast, the richness and diversity correlated negatively to disease incidence. Using LEfSe analyses, 11 taxa were found to be closely related with disease suppression, in which Saccharibacteria, Aeromicrobium, and Pseudoxanthomonas could be potential indicators of disease suppression. Our results suggested that the suppression of bacterial wilt after the application of soil amendments (especially oyster shell powder) was attributed to the improved soil pH and increased bacterial richness and diversity. Electronic supplementary material The online version of this article (10.1007/s00253-018-9347-0) contains supplementary material, which is available to authorized users.

Sourdough is widely used for the preparation of traditional sourdough breads in Europe and as an important inoculum for steamed buns prepared in Asian countries, especially China. This study aims to characterize Chinese traditional sourdoughs in terms of their taxonomic compositions, physicochemical characteristics, bacterial diversity and functional features. Thirty geographically diverse sourdoughs were collected from three regions across China. High-throughput sequencing and bioinformatics were used to characterize the bacterial diversity of the sourdoughs from the different sampling sites. The results showed that the West group was significantly different from the North and South groups in the dominant genera (mainly Lactobacillus, Pediococcus and Leuconostoc) and metabolic pathways (metabolism of terpenoids and polyketides, MTP, and xenobiotics biodegradation and metabolism, XBM), whereas samples from the North and South groups were not significantly different from each other. This is the first report of the genus Clostridium in sourdough and the first report of metabolic pathways related to MTP and XBM in sourdough. This research provides a thorough description and analysis of the relationship between bacterial diversity and geographic region in sourdough.

Mycotoxins are secondary metabolites produced by fungal species and have been reported to be carcinogenic, genotoxic, teratogenic, nephro- and hepatotoxic. Economic losses and health concerns due to mycotoxins occur at all levels of food and feed production, and this has attracted research interest towards exploring novel approaches to decontaminate and/or detoxify mycotoxin-contaminated food and feed. Therefore, we reviewed various strategies for the detoxification of mycotoxins, including pre-harvest prevention strategies and post-harvest detoxification procedures. Strategies for pre-harvest prevention include appropriate environmental factors, good agricultural and manufacturing practices, and favourable storage practices. For post-harvest detoxification strategies, physical, chemical, biological and other developing innovative strategies are discussed. This review is meant to be beneficial to the food industry and to contribute to assuring pre- and post-harvest management and processing practices that maximize consumer safety.

The crystallisation of methyl stearate under a range of crystallisation conditions has been studied and three new polymorphs have been identified and structurally characterised. Form III (monoclinic, space group Cc, Z = 8) was obtained at room temperature by slow evaporation of a saturated solution in CS2. Form IV (monoclinic, space group C2/c, Z = 4) was obtained by slow cooling of the melt. Both structures were characterised by single crystal X-ray diffraction. Form V (monoclinic, space group Cc, Z = 4) was obtained from the melt by rapid cooling. X-ray and neutron powder diffraction methods were employed in the determination of this structure. Form V shows highly anisotropic thermal expansion, with expansion along the crystallographic b-axis being substantially greater than along the other two axes.

Patulin contamination is a serious issue that restricts the development of the global fruit processing industry. Yeasts adsorb patulin more effectively than other microbial adsorbents, and this adsorption process depends mainly on the function of the cell wall. The present study examined the effect of exogenous calcium, in concentrations ranging from 0 to 1 mol/L, on

Precipitation and temperature in the Qilian Mountains and the Hexi oasis are changing with climate change. The characteristics and control factors of these changes are not well understood, affecting the ability to allocate water resources in this area judiciously. We analyzed the annual and seasonal variability in precipitation and temperature during 1960–2016 using monthly data from 25 national meteorological stations in the Qilian Mountains. Results showed that precipitation increased by 6.2, 4.1, and 8.9 mm/decade for the whole regions (including oasis and mountains), oasis, and mountains, respectively. Variability in summer precipitation made the greatest contribution to the annual change in precipitation. Moreover, the increment in precipitation was amplified with elevation. Enhanced westerly circulation and increased water vapor were the factors responsible for the increased precipitation in the study area. Temperature in the whole regions, oasis, and mountains increased at the rate of 0.32, 0.32, and 0.33 °C/decade, respectively. Changes in temperature were greatest in winter, with 0.47, 0.36 and 0.50 °C/decade in the whole regions, oasis, and mountains, respectively; changes in winter temperature made the greatest contribution to the annual temperature changes. Seasonal differences in carbon dioxide concentration may have caused the seasonal differences in the rate of temperature increase. The annual increase in temperature was mainly due to Siberian High, and Arctic Oscillation, carbon emissions and decreased cloud cover in the study area. The study results will help evaluate climatic hazards and contribute to development of water resources management strategies such as supplementary irrigation.

Obtaining the fingerprints of polysaccharides was known to be notoriously difficult by ambient mass spectrometry due to their resistance for desorption and ionization. Ambient mass spectrometry technology has recently been recognized as a quick analysis tool for obtaining fingerprints, which is attributed to its characteristics of no sample pretreatment and easy operation under atmospheric pressure. However, it still remains a challenge for accurate identification of the fingerprints of macromolecular polysaccharides by ambient micro-fabrication glow discharge plasma (MFGDP). In this study, a simplified methylation method was introduced to realize rapid analysis of polysaccharide mixture by MFGDP with the assistance of a temperature-programmed system (TPS). At the optimal temperature of TPS, oligosaccharides, plant polysaccharides and polysaccharide mixtures were all well characterized by TPS-MFGDP. In the proposed method, the characteristic [M + NH4] + adduct ions of oligosaccharides ions of oligosaccharides that are difficult for other ambient mass spectrometric methods were abundantly produced, making it possible to simultaneously identify a mixture of five or more polysaccharides. In addition, a supervised classification model which based on MS spectra, was used to classify seven typical hypoglycemic polysaccharides with excellent sensitivity, specificity and accuracy, indicating the good classification performance of the RF model constructed. Thus, the proposed mass spectroscopic method provides a cost effective, accurate and high throughput tool for identification and classification of polysaccharides, which is beneficial for studying the biological activity of polysaccharides.

This work reports a new acetonitrile (ACN)-solvated cocrystal of piroxicam (PRX) and succinic acid (SA), 2C15H13N3O4S·0.5C4H6O4·C2H3N or PRX:SA:ACN (4:1:2), which adopts the triclinic space group P\overline{1}. The outcome of crystallization from ACN solution can be controlled by varying only the PRX:SA ratio, with a higher PRX:SA ratio in solution unexpectedly favouring a lower stoichiometric ratio in the solid product. In the new solvate, zwitterionic (Z) and non-ionized (NI) PRX molecules co-exist in the asymmetric unit. In contrast, the nonsolvated PRX–SA cocrystal contains only NI-type PRX molecules. The ACN molecule entrapped in PRX–SA·ACN does not form any hydrogen bonds with the surrounding molecules. In the solvated cocrystal, Z-type molecules form dimers linked by intermolecular N—H...O hydrogen bonds, whereas every pair of NI-type molecules is linked to SA via N—H...O and O—H...N hydrogen bonds. Thermogravimetry and differential scanning calorimetry suggest that thermal desolvation of the solvate sample occurs at 148 °C, and is followed by recrystallization, presumably of a multicomponent PRX–SA structure. Vibrational spectra (IR and Raman spectroscopy) of PRX–SA·ACN and PRX–SA are also used to demonstrate the ability of spectroscopic techniques to distinguish between NI- and Z-type PRX molecules in the solid state. Hence, vibrational spectroscopy can be used to distinguish the PRX–SA cocrystal and its ACN solvate.

Patulin contamination is a severe issue that restricts the development of the global fruit processing industry. Yeast adsorbs patulin more effectively than other microbial adsorbents, and this adsorption process mainly depends on the function of the cell wall. Additionally, exogenous calcium ions aid in yeast cell wall formation according to reports. Therefore, in the present study, the effect of exogenous calcium concentrations on the cell wall structure and the patulin adsorption capability was studied. We showed that the ability of the yeast to adsorb patulin was strengthened with an increase in exogenous calcium concentrations between 1×10-4 - 1×10-2 mol/L. Moreover, yeast cell wall thickness, β-1,3-glucan content and the activities of the key catalytic enzymes β-1,3-glucanase and β-1,3-glycosyl transferase were all increased within this range. The results indicated that exogenous calcium activates key enzymes and that these enzymes are crucial for cell wall network formation and patulin adsorption capability.ImportanceThe present work illuminates that the exogenous calcium ions could determine the insoluble network structure by regulating key enzyme activities under certain concentrations, thus indirectly influencing the yeast cell patulin adsorption capability. It could enhance patulin adsorption capability of yeast walls and successfully apply to fruit juice industry.

With the development of educational informatization, the problem of data quality has become the main problem that restricts the development of educational informatization. It is particularly important to manage and improve the data quality at the life cycle of the data by intelligent means. This paper presents a data verification framework orienting education data based on rule base, and gives the hybrid data verification method. The method is applied to the education statistics foundation database platform in the data verification process, and improves the precision of data.

A series of CHA-type trimetallic composite zeolites of Cex–Fey/Cu–SSZ-13 catalysts were prepared using Cu–SSZ-13, synthesized in a one-pot procedure, and subsequent ion-exchange with Fe3+ and Ce3+. The catalysts were characterized including TEM, XRD, XPS, SEM and BET. Their catalytic performances for selective catalytic reduction of NO with NH3 were investigated. The results of XRD revealed that the crystal structure of zeolite Ce–Fe/Cu–SSZ-13 is the same as Cu–SSZ-13. It is known from the results of BET and catalytic performance tests that larger specific surface areas and smaller pore size favor a catalytic reaction. Among the prepared Cex–Fey/Cu–SSZ-13 catalysts, Ce0.017–Fe0.017/Cu–SSZ-13 displayed the best SCR performance. The NO conversion was more than 90% between 200 and 500 °C. N2 selectivity was above 98% within the wider temperature range of 150–550 °C. In addition, the catalyst demonstrated sulfur–water tolerance and effective resistance against high space velocity. The phenomena suggest that synergistic effects of Cu, Fe and Ce species improve the SCR performances and make the Ce–Fe/Cu–SSZ-13 catalyst a promising candidate for NH3–SCR technology.

Purpose The objective of the study was to examine the associations of cruciferous vegetables intake with risk of breast cancer. Methods Studies were identified by searching PubMed databases and screening the references of retrieved articles and reviews. Summary odds ratios (ORs) for the highest versus lowest cruciferous vegetables consumption levels were calculated using fixed or random effects models depending on heterogeneity between studies. Heterogeneity among studies was examined using Q and I 2 statistics. Publication bias was assessed using the Egger's and Begg's tests. Results Thirteen epidemiologic studies (11 case-control and 2 cohort studies) were included in the meta-analysis. The combined results from all studies indicated that high cruciferous vegetables intake was significantly associated with reduced breast cancer risk (RR = 0.85, 95% CI = 0.77–0.94). Conclusion Findings from this meta-analysis suggest that cruciferous vegetables consumption may reduce the risk of breast cancer. Because of the limited number of studies, further prospective studies are needed to explore the protective effect of cruciferous vegetables on breast cancer.

A variety of linear and side-chained p-nitrostilbene derivatives with various numbers of bromine atoms were prepared to survey the crystal structural properties, the photoluminescence, and heavy atom effect on the singlet oxygen generation by two-photo absorption (TPA). Single crystals of 4-nitro-4′-(4″-bromo-phenyl-methyl-oxy)-diphenylethylene (C2), 4-nitro-4′-(3″,5″-dibromo-phenyl-methyl-oxy)-diphenylethylene (C3), 4-nitro-4′-(2′,3″,4′,5″,6″-pentabromo-phenyl-methyl-oxy)-diphenylethylene (C4) were obtained, and the structural characteristics were analyzed by X-ray diffraction. One- and two-photon optical properties of the photosensitizers are shown dependence on the numbers of substituted bromine atoms. While TPA cross-sections of the photosensitizers are diminished more considerably, singlet oxygen quantum yields of the photosensitizers are enhanced at some extents by the substituted bromine atoms. Side-chained photosensitizers display correspondingly higher singlet oxygen quantum yields and larger TPA cross-sections than the molecules with single bromine-substituted aromatic segment. Molecular modeling was also performed to reveal the fundamental reasons of the experimental observation. Photooxidation reaction of singlet oxygen with some substrates was employed to confirm singlet oxygen generation under one- and two-photon irradiation.

Additional file 1: Figure S1. Disease incidence of ginger bacterial wilt. Figure S2. The rarefaction curve of samples. Table S1. Soil Physicochemical Data. Table S2. The top ten Phyla of samples. Dataset S1. Discriminative taxa analyzed by LEfSe in all samples.