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Listeria monocytogenes is a widespread foodborne pathogen contaminating foods during their production or processing stages. Fresh meat is susceptible to such contamination if it is not properly preserved. Our study was conducted to reveal the level of contamination and prevalence of Listeria spp. present in livestock and poultry meat from Gansu province. A total of 1,387 samples were collected from five cities in Gansu Province according to standard sampling procedures, of which 174 samples (12.5%) were positive for Listeria species. Among them, 14 isolates of L. monocytogenes (1.0%), 150 isolates of Listeria innocua (10.8%), and ten isolates of Listeria welshimeri (0.7%) were identified by conventional bacteriological and molecular identification methods. All isolates were subjected to serological assays, antimicrobial susceptibility tests, growth curve assays, determination of biofilm-forming capacity, and cluster analysis of the 16S rRNA gene sequences. Four predominant serotypes of L. monocytogenes were identified, including 1/2a (35.7%, 5/14), 1/2b (14.3%, 2/14), 1/2c (42.9%, 6/14), and 4b (7.1%, 1/14). All L. monocytogenes isolates were resistant to tetracycline and cefoxitin. Most L. innocua isolates (63.6%, 14/22) and L. welshimeri (40%, 4/10) were resistant to tetracycline. The high biofilm-forming ability was observed among 1/2c and 1/2a serotype isolates. The cluster analysis of the 16S rRNA gene sequences revealed a close genetic relationship between the three Listeria species. This study fills the gap in the knowledge of livestock and poultry meat that carry Listeria in slaughterhouses and markets in Gansu Province.

In this paper, we develop two finite difference weighted essentially non-oscillatory (WENO) schemes with unequal-sized sub-stencils for solving the Degasperis-Procesi (DP) and $\mu$-Degasperis-Procesi ($\mu$DP) equations, which contain nonlinear high order derivatives, and possibly peakon solutions or shock waves. By introducing auxiliary variable(s), we rewrite the DP equation as a hyperbolic-elliptic system, and the \mdp equation as a first order system. Then we choose a linear finite difference scheme with suitable order of accuracy for the auxiliary variable(s), and two finite difference WENO schemes with unequal-sized sub-stencils for the primal variable. One WENO scheme uses one large stencil and several smaller stencils, and the other WENO scheme is based on the multi-resolution framework which uses a series of unequal-sized hierarchical central stencils. Comparing with the classical WENO scheme which uses several small stencils of the same size to make up a big stencil, both WENO schemes with unequal-sized sub-stencils are simple in the choice of the stencil and enjoy the freedom of arbitrary positive linear weights. Another advantage is that the final reconstructed polynomial on the target cell is a polynomial of the same degree as the polynomial over the big stencil, while the classical finite difference WENO reconstruction can only be obtained for specific points inside the target interval. Numerical tests are provided to demonstrate the high order accuracy and non-oscillatory properties of the proposed schemes.

The characteristics of isolated deep convection initiation (DCI) and its relation to topography in the North China area are studies statistically and numerically. The infrared brightness temperature data from satellite Himawari-8 are utilized to identify DCI events in three summers. A total of 2534 DCI events are obtained and their locations show clustering over mountains and hills, suggesting the significance of local topography. Topography is described with elevation and relief amplitude. DCI events and grid boxes are counted. DCI events per grid box increases with elevation and relief amplitude. Among different types of topography, DCI is favored in mountains and hilly areas. Moreover, the morning cloud cover condition also shows notable impact on the relation of DCI and topography. For the regime characterized with less morning clouds (regime one), DCI strongly depends on elevation and relief amplitude, while for the regime with more morning clouds (regime two), topography shows a moderate impact on DCI. The time of DCI events are also recorded, and regime one shows a stronger diurnal variation and a peak occurring 2 hours earlier than that of regime two. The synoptic patterns show the difference of large-scale environment between the two regimes, which can explain their differences in DCI to some extent. To clarify the mechanism of topographic effect in DCI process, quasi-idealized numerical simulation in North China is conducted with WRF. The averaged 6-hourly ERA-Interim reanalysis data, which can maintain the major patterns of large-scale circulations, are inputted into the model as initial and boundary conditions. The elevation and relief amplitude of the study domain is varied in the model. The preliminary result shows that the speed of upscale convection growth changes with elevation and relief amplitude, which indicates that mechanisms involving topography-induced variation of solar heating may exist and need further numerical study. We suggest that special attention should be paid to elevation and relief amplitude (or topography type), as well as morning cloud cover condition when forecasting DCI in the North China area and mountainous areas around the world.

Secondary ice processes (SIPs) can produce ice crystals with a number concentration much higher than that of ice nucleating particles (INPs) in mixed-phase clouds, and therefore influence cloud glaciation and precipitation. But the role of SIPs in midlatitude continental mesoscale convective systems (MCSs) such as squall lines is still unknown. This study investigates the relative importance of rime splintering, freezing drop shattering, and collision breakup in the mature stage of a squall line case in North China on 18 August 2020 using the WRF model. The simulations show that collision breakup has the most pronounced effect on ice production, and rime splintering plays a secondary role. It is because ice multiplication from SIPs can feedback to collision breakup and rime splintering in different ways. Collision breakup has a positive feedback because the numerous snow and graupel from SIPs in turn promote a higher collision breakup rate, while rime splintering is limited by itself and also limited by collision breakup because the weaker riming due to the two SIPs leads to a lower rime splintering rate. Freezing drop shattering has a negligible effect on ice production because there are few large droplets in the mature stage. Collision breakup can also redistribute surface precipitation in the squall line, which decreases in the convective region and increases in the stratiform region. The influence of aerosols as CCN and INPs on SIPs is further studied. Preliminary simulation results show that the effects of aerosol concentration on the rate of SIPs and anvil ice concentration are nonlinear. The mechanism remains to be analyzed.

Insoluble particles affect weather and climate indirectly by heterogeneous freezing process. Current weather and climate models have large uncertainty in freezing process simulation due to little regarding species and number concentration of heterogeneous ice-nucleating particles, mainly insoluble particles. Here, for the first time, size distribution and species of insoluble particles are analyzed in 30 shells of 12 hailstones in China, using scanning electron microscopy and energy dispersive X-ray spectrometry. Total 289,461 insoluble particles are detected and grouped into 3 species: organics, dust, and bioprotein by machine learning methods. The size distribution of insoluble particles of each species vary greatly in different hailstorms but little in shells. Further, classic size distribution modes of organics and dust were performed as logarithmic normal distributions, which may be adapted in future weather and climate models though uncertainty still exists. Our finding suggests that physical properties of aerosols should be considered in model simulation on ice freezing process.

In order to clarified characteristics and function of internalin G (inlG) in Listeria monocytogenes ATCC®19111 (1/2a) (LM), the immune protection of the inlG was evaluated in mice, the homologous recombination was used to construct inlG deletion strains, and their biological characteristics were studied by the transcriptomics analysis. As a result, the immunization of mice with the purified protein achieved a protective effect against bacterial infection. The deletion strain LM-AinlG was successfully constructed with genetic stability. The mouse infection test showed that the virulence of LM was decreased after the deletion of the inlG gene. The deletion strain showed enhanced adhesion to and invasion of Caco-2 cells. Compared to the wild strain, 18 genes were up-regulated, and 24 genes were down-regulated in the LM-AinlG. This study has laid a foundation for further research on the function of inlG and the pathogenesis of LM. In this study, immunization of mice with the purified inlG protein achieved a protective effect against Listeria monocytogenes infection. The virulence of LM-ΔinlG was decreased by mouse infection. However, the adhesion and invasion ability to Caco-2 cell were enhanced. Compared to the wild strain, 18 genes were up-regulated, and 24 genes were down-regulated in the LM-ΔinlG. This study has laid a foundation for further study of the function of the inlG and the listeriosis.

Meat yield and quality are important economic traits of livestock. Herein, longissimus dorsi (LD) muscles of Leizhou black goats aged 0, 3, and 6 months were used to identify differentially expressed messenger RNAs (mRNAs) and long non-coding RNAs (lncRNAs) by high-throughput RNA sequencing. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were used to analyze differentially expressed genes. Expression levels of regulator of calcineurin 1 (RCAN1) and olfactory receptor 2AP1 (OR2AP1) were significantly different in LD muscles of goats aged 0, 3, and 6 months, indicating potentially important roles in postnatal muscle development. Differentially expressed lncRNAs and mRNAs were mainly enriched in biological processes and pathways related to cellular energy metabolism, consistent with previous studies. Three lncRNAs, TCONS_00074191, TCONS_00074190, and TCONS_00078361, may play a cis-acting role with methyltransferase-like 11B (METTL11B) genes and participate in the methylation of goat muscle proteins. Some of the identified genes may provide valuable resources for future studies on postnatal meat development in goat muscles.

Biofilm (BF) formation is a considerable obstacle to the effective control of Listeria monocytogenes (LM). In this study, we used transcriptomics to analyze LM BF and planktonic bacteria at different stages of BF formation and growth to compare differential gene expression between the 2. We identified 1588, 1517, and 1462 differentially expressed genes (DEGs) when early formation BF and planktonic bacteria were compared at 12, 24, and 48 h, respectively. Among these, 1123 DEGs were shared across the 3 data pool. Gene Ontology functional enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses demonstrated significant changes associated with the phosphotransferase system, the microbial metabolism in diverse environments, the flagella assembly, the bacterial chemotaxis, the bacterial secretion, the quorum sensing, and the 2-component system. The top 5 upregulated DEGs were lmo0024, lmo0374, lmo0544, hly, and lmo2434. The top 5 downregulated DEGs were lmo2192, lmo1211, cheY, lmo0689, and secY. After real-time quantitative polymerase chain reaction, the expression of these 10 DEGs were consistent with the results of the transcriptomic sequence. This research lays the foundation for further studies on mechanisms regulating BF formation and will help to identify BF inhibitors to reduce the risk of LM infection.

Background: Meat yield and quality is one of the most important economic traits of livestock. Long non-coding RNAs (lncRNAs) is involved in the biological process of muscle differentiation and development. However, few studies have explored the regulatory role of lncRNA on muscle development after birth.Results: The longissimus dorsi muscle of Leizhou black goat aged 0, 3 and 6 months was used to identify differential mRNA and differential lncRNA by high-throughput RNA sequencing. GO, KEGG and interaction network were used to analyzed the differential genes. We found that some target genes of DE-mRNA and DE-lncRNA were mainly involved CN-NFAT signal pathway and the formation of branch fibers, which is related to normal muscle development. ENSCHIG00000006085 and ENSCHIG00000023270 are significantly concentrated in the biological process related to urea transporters, which has an important effect on maintaining the normal development of goats. ENSCHIG00000006085 and ENSCHIG00000023270 may be involved in the degradation of intracellular proteins and METTL11B may play a role in methylation modification of muscle proteins.Conclusions: Our results show that some lncRNAs are involved in the regulation of protein during goat muscle development as well as provide a valuable resource for lncRNA studies and make a deeper understanding of the genetic basis and molecular mechanisms of the development of goat skeletal muscle.

Sea-breeze fronts (SBFs) are frequently found to trigger deep convection. The convective updrafts near the SBF are critical in this triggering process. Here, the size and strength of the updrafts near an idealized SBF are investigated with large-eddy simulations. A central focus of this study is to compare the updrafts near the SBF, which are substantially affected by the SBF, to the updrafts ahead of the SBF, which develop in a typical convective boundary layer. It is found that the updrafts near the SBF are larger than but have similar strength to the updrafts ahead of the SBF. The larger updrafts near the SBF are produced through the merger between the postfrontal streaky structures and the updrafts originating near the SBF. Lagrangian budget analysis of vertical momentum reveals that the dynamics experienced by the parcels constituting the updrafts near the SBF is almost the same as that ahead of the SBF, so that the strength of the updrafts near the SBF is similar to that ahead of the SBF. It is also found that when the environmental wind is not included, the size and strength of the updrafts near the SBF scale with the boundary-layer height and the convective velocity scale, respectively, like those in the typical convective boundary layer; however, when the environmental wind is included, the aforementioned scaling breaks down. The present results should also apply to other boundary-layer convergence lines similar to the SBF.

Synoptic meteorology is a branch of meteorology that uses synoptic weather observations and charts for the diagnosis, study, and forecasting of weather. Weather refers to the specific state of the atmosphere near the Earth’s surface during a short period of time. The spatial distribution of meteorological elements in the atmosphere can be represented by a variety of transient weather phenomena, which are caused by weather systems of different spatial and temporal scales. Weather is closely related to people’s life, and its development and evolution have always been the focus of atmospheric scientific research and operation. The development of synoptic meteorology is closely related to the development of observation systems, dynamical theories and numerical models. In China, observation networks have been built since the early 1950s. Up to now, a comprehensive meteorological observation system based on ground, air and space has been established. In particular, the development of a new generation of dense radar networks, the development of the Fengyun satellite series and the implementation of a series of large field experiments have brought our understanding of weather from large-scale environment to thermal dynamics, cloud microphysical structure and evolution characteristics of meso and micro-scale weather systems. The development of observation has also promoted the development of theory, numerical model and simulation. In the early days, China mainly used foreign numerical models. Lately, China has developed numerical model systems with independent intellectual property rights. Based on the results of high-resolution numerical simulations, in-depth understanding of the initiation and evolution mechanism and predictability of weather at different scales has been obtained. Synoptic meteorology has gradually changed from an initially independent development to a multidisciplinary approach, and the interaction between weather and the change of climate and environment has become a hot and frontier topic in atmospheric science. This paper reviews the important scientific and technological achievements made in China over the past 70 years in the fields of synoptic meteorology based on the literatures in China and abroad, from six aspects respectively including atmospheric dynamics, synoptic-scale weather, typhoon and tropical weather, severe convective weather, numerical weather prediction and data assimilation, weather and climate, atmospheric physics and atmospheric environment.

Orographic precipitation is, on the one hand, an important source of fresh water, and on the other hand, a potential cause of floods and other disasters. Previous studies have focused on the situation where the whole atmosphere is saturated and nearly moist-neutral. However, there are times when subsaturated low-level layers are observed to be below saturated, nearly moist-neutral, upper-level layers.A series of idealized two-dimensional simulations are performed here to investigate the impact of this subsaturated low-level layer on orographic precipitation. It is found that the impact is mainly controlled by a nondimensional parameter and two competing effects. The nondimensional parameter is N2zt/U, where N2 and zt are, respectively, the dry Brunt–Väisälä frequency and depth of the subsaturated low-level layer, and U the cross-mountain wind speed. When the nondimensional parameter exceeds a critical value, the decelerated region on the upwind side of the mountain moves upwind, resulting in weak surface precipitation near the mountain peak. When it is smaller than the critical value, surface precipitation occurs near the mountain peak.The two competing effects are: 1) the vapor-transport effect, meaning that increasing zt decreases the amount of vapor transported to the mountain, and hence tends to decrease surface precipitation; and 2) the updraft width effect, meaning that increasing zt enhances flow blocking, producing a wider updraft over the upwind slope, and hence tends to increase surface precipitation. When the vapor-transport effect dominates, surface precipitation decreases with zt. When the updraft-width effect dominates, surface precipitation increases with zt.

An autumnal Arctic mixed-phase cloud case from the Mixed-Phase Arctic Cloud Experiment is simulated with the Weather Research and Forecasting model with a prognostic ice-nucleating particle (INP) formulation to investigate the mechanisms sustaining the continuous ice formation. When the model is run with only primary ice production (PIP) processes, it needs 100 times the observed INP concentration to reproduce the observations. When a secondary ice production (SIP) process, i.e., droplet shattering when supercooled droplets freeze heterogeneously, is added, the model needs 50 times the observed INP concentration to reproduce the observations. Two factors are found to reduce the INP concentration required to reproduce the observations. First, as the cloud moves over the open ocean, the cloud top rises quickly, resulting in a cloud top entrainment rate of ~3.0 cm s−1, which is 4 times as large as that in previous large-eddy simulations of the same case. More INPs can hence be entrained into the cloud. Second, INPs are recycled when ice crystals are completely sublimated below the cloud base. Sensitivity tests show that INP recycling reduces the required INP concentration by a factor of 4. In addition, offline tests show that another two SIP processes, i.e., droplet shattering when supercooled droplets collect small ice crystals and breakup during ice-ice collision, do not substantially contribute to the ice formation in this case.

In this letter, trench-gate metal–oxide–semiconductor field-effect transistors on (010) $\beta $ -Ga2O3 epitaxial layer are fabricated. Enhancement mode is achieved by the gate-recess process, through thoroughly depleting the $\beta $ -Ga2O3 channel to get a positive threshold voltage. For the first time, by using a dynamic parameter test system, the Ga2O3 MOSFET with 2- $\mu \text{m}$ gate length is characterized to present short switching time, including turn-on time ( $\textit {t}_{ \mathrm{\scriptscriptstyle ON}}$ ) of 28.6 ns and turn-off time ( $\textit {t}_{ \mathrm{\scriptscriptstyle OFF}}$ ) of 94.0 ns. In addition, OFF-state interelectrode parasitic capacitances, including input capacitance ( $\textit {C}_{\text {iss}}$ ) of 37 pF/mm, output capacitance ( $\textit {C}_{\text {oss}}$ ) of 42 pF/mm, and reverse transfer capacitance ( $\textit {C}_{\text {rss}}$ ) of 14 pF/mm are also obtained, which can account for the high switching speed. The static and dynamic switching properties of the trench-gate device show the potential of $\beta $ -Ga2O3 MOSFET for the high-speed switching applications.

To investigate the transport and formation mechanism of pollution in Beijing, this study explored the vertical profiles of aerosol properties using aircraft measurement during a regional transport (RT) pollution event from 10th to 12th December 2016. The aerosol chemical composition and size distribution were characterized. Different vertical structures exhibited during three periods (defined as before RT, during RT, and after RT) for this pollution event. Before RT, PM2.5 and black carbon (BC) mass loading were at low level in the mixing layer (ML) when the clean northerly air mass dominated. During RT, an elevated aerosol layer, in which BC and PM2.5 mass concentrations were about 1.5 times higher than that at the ground level, was found in the upper ML (at 400–900 m) over Beijing. This elevated aerosol layer was advected by the prevailing southwesterly air mass which transported the pollutants from the intensively polluted southwestern region over Beijing. These aerosols through RT featured with pronounced secondary compositions and large coatings on BC particles. After RT, the pollutants were significantly diluted by the prevailing NW air mass, whereas the aerosol concentration almost maintained in the near surface, leading to notable vertical gradient. The continued surface pollution may result from the low wind speed and secondary aerosol formation in the next day. This study suggests that only the ground observation could not fully explain the pollution event, but the variation of vertical structure of aerosol properties should be considered to elucidate the formation mechanism of pollution over Beijing.

Rabbit hemorrhagic disease virus (RHDV) is the causative agent of rabbit hemorrhagic disease (RHD), and its infection results in mortality of 70&ndash, 90% in farmed and wild rabbits. RHDV is thought to replicate strictly in rabbits. However, there are also reports showing that gene segments from the RHDV genome or antibodies against RHDV have been detected in other animals. Here, we report the detection and isolation of a RHDV from diseased Alpine musk deer (Moschussifanicus). The clinical manifestations in those deer were sudden death without clinical signs and hemorrhage in the internal organs. To identify the potential causative agents of the disease, we used sequence independent single primer amplification (SISPA) to detect gene segments from viruses in the tissue samples collected from the dead deer. From the obtained sequences, we identified some gene fragments showing very high nucleotide sequence similarity with RHDV genome. Furthermore, we identified caliciviral particles using an electron microscope in the samples. The new virus was designated as RHDV GS/YZ. We then designed primers based on the genome sequence of an RHDV strain CD/China to amplify and sequence the whole genome of the virus. The genome of the virus was determined to be 7437 nucleotides in length, sharing the highest genome sequence identity of 98.7% with a Chinese rabbit strain HB. The virus was assigned to the G2 genotype of RHDVs according to the phylogenetic analyses based on both the full-length genome and VP60 gene sequences. Animal experiments showed that GS/YZ infection in rabbits resulted in the macroscopic and microscopic lesions similar to that caused by the other RHDVs. This is the first report of RHDV isolated from Alpine musk deer, and our findings extended the epidemiology and host range of RHDV.

Mycoplasma bovis is an extremely small cell wall-deficient pathogenic bacterium in the genus Mycoplasma that causes serious economic losses to the cattle industry worldwide. Fructose-1,6-bisphosphate aldolase (FBA), a key enzyme in the glycolytic pathway, is a multifunctional protein in several pathogenic bacterial species, but its role in M. bovis remains unknown. Herein, the FBA gene of the M. bovis was amplified by PCR, and subcloned into the prokaryotic expression vector pET28a (+) to generate the pET28a-FBA plasmid for recombinant expression in Escherichia coli Transetta. Expression of the 34 kDa recombinant rMbFBA protein was confirmed by electrophoresis, and enzymatic activity assays based on conversion of NADH to NAD+ revealed Km and Vmax values of 48 μM and 43.8 μmoL/L/min, respectively. Rabbit anti-rMbFBA and anti-M. bovis serum were generated by inoculation with rMbFBA and M. bovis, and antigenicity and immunofluorescence assay demonstrated that FBA is an immunogenic protein expressed on the cell membrane in M. bovis cells. Enzyme-linked immunosorbent assays revealed equal distribution of FBA in the cell membrane and cytoplasm. Complement-dependent mycoplasmacidal assays showed that rabbit anti-rMbFBA serum killed 44.1% of M. bovis cells in the presence of complement. Binding and ELISA assays demonstrated that rMbFBA binds native bovine plasminogen and in a dose-dependent manner. Fluorescent microscopy revealed that pre-treatment with antibodies against rMbFBA decreased the adhesion of M. bovis to embryonic bovine lung (EBL) cells. Furthermore, adherence inhibition assays revealed 34.4% inhibition of M. bovis infection of EBL cells following treatment with rabbit anti-rMbFBA serum, suggesting rMbFBA participates in bacterial adhesion to EBL cells.

A series of measurements of ice-nucleating particles (INPs) were performed at two sites in Beijing. At the Beijing Meteorological Service (BMS) site, which was an urban site, no INPs were found to be active above –15°C. However, at the Yanjiaping (YJP) site, which was a rural site, the concentration of INPs active at temperatures above –15°C was found to be as high as 1.73 g–1. Two parameterizations were constructed by respectively fitting the data obtained at BMS site and YJP site. The two parameterizations, as well as another parameterization from the literature, were implemented into a parcel model to investigate the effect of INPs active above –15°C on phase partitioning in mixed-phase clouds. At a vertical velocity of 0.01 m s–1, which is typical for stratiform clouds associated with frontal systems, the INPs active above –15°C nucleate ice crystals at low levels. The growth of these ice crystals remarkably reduces both the maximum liquid water mixing ratio and the altitude where the maximum liquid water mixing ratio is reached. When the vertical velocity of the parcel is increased to 0.1 m s–1 or an even higher value, the evolution of liquid water mixing ratio is not controlled by the INPs active above –15°C but those active below –15°C.