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Objective To understand the distribution of clustered regularly interspaced short palindromic repeats (CRISPR) in Staphylococcus aureus and analyze their effects on the horizontal transfer of antibiotic resistance gene and virulence gene.Method Total 575 complete S. aureus genomes were obtained from public databases, and bioinformatics methods were used to count the CRISPR carriage, multi-locus sequence typing (MLST) types distribution of strains and the distribution of strain drug resistance genes and virulence genes. The significance analysis of the difference in the number of drug resistance genes and virulence genes was carried out between CRISPR structure-positive (CRISPR+) and CRISPR structure-negative (CRISPR−) S. aureus. The data of 60 strains of S. aureus were also analyzed by second-generation sequencing to verify the results of public database analysis. We also counted the carriage of prophages and conjugative plasmids in 60 strains of S. aureus in the laboratory, and discussed the effect of CRISPR structure on the prophages and conjugative plasmids of the strains.Result Among the 575 strains with complete genome assembly, there were 62 strains with CRISPR structure (CRISPR+) and 513 strains without (CRISPR−). The number of drug resistance genes and virulence genes of CRISPR+ S. aureus was less than that of CRISPR− S. aureus, and the difference was significant. Among 60 strains of S. aureus in the laboratory, there were 14 strains of CRISPR+ and 46 strains of CRISPR−. CRISPR+ S. aureus carried fewer drug resistance genes and virulence genes, which was consistent with the results of the public database analysis. Analysis of prophages and conjugative plasmids showed that CRISPR− strains carried more prophage sequences, which were significantly different from CRISPR+ strains (P<0.05). For conjugative plasmids, CRISPR− and CRISPR+ strains were largely consistent with no significant difference.Conclusion CRISPR structure may limit the horizontal transfer of drug resistance and virulence genes in S. aureus, and CRISPR− strains are more susceptible to be interfered by phage and removable plasmids. This study provides a reference for further research on transmission of drug resistance and virulence genes in S. aureus.

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Objective To knock out the target chromosome by CRISPR/Cas9 system to cut multiple sites of Y chromosome, and provide a new method for sex control of livestock and poultry. Method Based on CRISPR/Cas9 technology, we searched for multiple copies of repeat sequences on Y chromosome that can be specifically recognized by sgRNA, and verified their effectiveness on target by in vitro cleavage, quantitative analysis and karyotype identification. Result The designed sgRNA could cut the target fragment obviously in vitro, and the cutting efficiency was more than 50%. The results of quantitative analysis of genes further proved the effectiveness of gene cutting at the cell level, and the cutting effect of clustered repeats was significantly better than that of scattered repeats. Karyotype identification also confirmed the loss of pig Y chromosome at the cellular level. Conclusion The research results lay a foundation for the subsequent construction of chromosome knockout pigs and the realization of sex control in pigs.

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Objective It is still unclear whether miR-146a, as an anti-inflammatory factor, is involved in the interaction between host and microbes, and then affects intestinal homeostasis. Therefore, this study aims to investigate the effect of miR-146a on the intestinal flora of mice.Method Intestinal miR-146a-specific knockout mice (CKO mice) and control mice (Flox mice) were used as research subjects, and the 16S rRNA high-throughput sequencing method was used to detect the distribution of microflora in the jejunum of the two groups. Result Through sequencing, we obtained a total of 1 134 OTUs for species classification, including 37 phyla, 80 classes, 161 orders, 198 families, 261 genera and 117 species of bacteria. There were a total of 46 identical OTUs in the jejunal microbes of the Flox group and CKO group. Firmicutes, Bacteroidota, Verrucomicrobiota, Proteobacteria and Desulfobacterota were the dominant bacteria in gut microbes of each group. The gut microbial community compositions of the two groups were generally similar, while the average abundance of Clostridia in the CKO group was higher than that in the Flox group (P=0.067), and the average abundance of Lachnospirales in the CKO group was significantly higher than that in the Flox group (P<0.05). There was no significant difference in the composition of other levels. Conclusion Knockout of miR-146a can alter the contents of Clostridia and Lachnospirales microorganisms in the host gut, which provides a reference for studying how miR-146a affects gut health by altering host gut microbes.

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Objective To investigate the effects of the whole length of Duck Tambusu virus (DTMUV) E protein and its domains of I, II and III (DI, DII and DIII) on the cell cycle and apoptosis of duck embryo fibroblast (DEF) cells. Method The full-length of DTMUV E protein, DI, DII and DIII eukaryotic expression plasmids were designed and synthesized, and transfected into DEF. The changes of DEF apoptosis and cell cycle caused by different proteins were detected by flow cytometry. Result The results of apoptosis showed that after 24 h of plasmid transfection, the apoptosis rates of DEF induced by the full length, DI, DII and DIII were 16.4%, 15.1%, 14.0% and 17.2% respectively; after 36 h of plasmid transfection, the apoptosis rates of DEF induced by E protein full length, DI, DII and DIII were 23.4%, 18.5%, 26.7% and 29.4%. The results of cell cycle detection showed that the percentage of DNA synthesis phase (S-phase) cells transfected with E protein full length, DI, DII and DIII plasmid was obviously higher than those of cells transfected with pEGFP-N1 empty vector 24 h and 36 h later. After 24 h of plasmid transfection, the percentage of S-phase cells in E protein, DI, DII and DIII groups were 5.43%, 22.58%, 12.75% and 12.80%, respectively; After 36 h of plasmid transfection, the percentage of S-phase cells in E protein, DI, DII and DIII groups were 9.98%, 11.44%, 10.44% and 11.00%, respectively. Conclusion The full length of DTMUV E protein and its three domains can induce early cell apoptosis and arrest the S-phase cells, but the ability of each protein fragment to induce cell apoptosis and change the cell cycle is different.

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Objective To investigate the effects of feeding Clostridium butyricum (CB) spores on the growth performance, biochemical parameters in serum, intestinal flora composition and contents of five short-chain fatty acids of Paneaus vannamei juvenile. Method Basic diets were supplemented with CB spore product of 0, 0.050%, 0.075% and 0.100% mass fraction (The viable counts of bacteria in the diets were 0, 2.50×10⁵, 3.75×10⁵ and 5.00×10⁵ CFU/g respectively). The P. vannamei juveniles with (1.42 ± 0.02) g initial body weight of each were fed for 30 days，and growth performance, serum biochemical indicators, intestinal flora composition and short chain fatty acid contents were detected.Result Compared to the control group, the final body weights of the shrimps after 30 days feeding trial in the 0.050% and 0.075% CB groups significantly increased (P<0.05), and the weight gain rate significantly increased in the 0.050% CB group (P<0.05). The glucose concentration in serum of the 0.075% CB group and urea nitrogen concentration in serum of the 0.100% CB group significantly reduced (P<0.05), while the phosphorus concentration in serum of the 0.050% CB group significantly increased (P<0.05). Compared to the control group, the relative abundance of Planctomycetes and Patescibacteria significantly increased in the 0.050% CB group (P<0.05), while the relative abundance of Vibrio significantly reduced in the 0.050% and 0.075% CB groups (P<0.05). The diversity analysis indicated that the intestinal flora compositions were similar between the 0.050% and 0.075% CB groups, which were quite different from those of the control and 0.100% CB group. The intestinal contents of five short-chain fatty acids increased with dietary CB addition. Conclusion The supplementation of CB spore in diets helps to inhibit the proliferation of intestinal pathogens and increase the contents of intestinal short chain fatty acids, thus may enhance the nutrients utilization and growth performance of P. vannamei juvenile. In this study, the appropriate amount of Clostridium butyricum spore in diet is 2.50×10⁵ or 3.75×10⁵ CFU/g.

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目的 低磷和铝毒胁迫是酸性土壤中限制作物生产的重要因素。植物NTL转录因子参与调控多种环境胁迫(包括铝毒胁迫)的适应性机制，本文探究GmNTLs调控大豆Glycine max 根系响应低磷胁迫的功能。方法 通过RT-qPCR分析大豆15个GmNTLs基因在根系响应低磷胁迫的表达模式，进一步构建了GmNTL1/4/7/8/10/12共6个GmNTLs基因的拟南芥超量表达材料，探究GmNTL成员在拟南芥根系中响应低磷胁迫的功能。结果 系统进化树及组织表达模式分析结果表明，GmNTLs家族分3个亚族，各亚族成员在大豆中组织表达模式不同。RT-qPCR结果表明，低磷处理12 d显著提高了GmNTL1/4/7/8/10/12在大豆根系中的表达。在拟南芥中超量表达不同GmNTL基因对低磷的响应不同。高磷处理下，超量表达GmNTL4/10/12拟南芥的鲜质量显著增加；低磷处理时，超量表达GmNTL4显著提高拟南芥鲜质量，而超量表达GmNTL1/12拟南芥的鲜质量显著降低。同时，仅超量表达GmNTL12拟南芥的主根长显著缩短，而超量表达其他基因对拟南芥植株的主根长无明显影响。结论 GmNTLs参与大豆根系对低磷胁迫的响应，该结果可为培育磷高效型大豆品种提供数据支持。

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Objective To study the effects of drip irrigation nitrogen (N) chasing management on soil N fraction and N₂O emission in host cane fields, and reveal the soil factors affecting soil N₂O fluxes.Method Two water drip irrigation levels of W0.8 (70%?80% of field water holding capacity) and W0.9 (80%?90% of field water holding capacity) and three drip irrigation N chasing ratios (250 kg·hm^?2 of equal N) were carried out in a mobile rain-proof shelter with the second generation host cane (Saccharum officinarum) as the research object. N0 was all the N fertilizer applied to the soil (referred to as soil-applied N); N5 was 50% soil-applied N and 50% applied by drip irrigation system (referred to as drip-applied N); N7 was 30% soil-applied N and 70% drip-applied N in the field trials. Soil N₂O flux, pH and nitrogen fraction content were measured at each period of sugarcane growth, and the relationship between soil N₂O flux and soil pH/nitrogen fraction content was analyzed.Result Soil N₂O flux was higher after two days of applying N fertilizer and water irrigation, and the soil N₂O flux of W0.9N5 was significantly lower than other treatments at the late tillering stage and maturity stage. Under W0.9, the cumulative soil N₂O emissions in N5 at the late tillering stage were 47.3% and 11.8% lower than those of N0 and N7, and 21.5% lower than those of N7 at the late elongation stage. Soil nitrate N content showed W0.9 > W0.8 for the same drip irrigation N rate, and increased with the increase of water irrigation. At the early elongation and maturity stage, the soil ammonium N content of N5 under W0.8 was 56.4% and 71.8% higher than those of N0, was 68.5% and 160.3% higher than those of N7. At the late tillering stage, soil microbial biomass nitrogen showed N5 > N7 > N0 under the same water drip irrigation level, and soil microbial biomass nitrogen of N5 was 120.0% and 100% higher than N0 under both water irrigation rates, respectively. There was a positive correlation between soil N₂O flux and ammonium N content (r=0.313) and a negative correlation with nitrate N (r=?0.391).Conclusion W0.9N5 treatment can reduce soil N₂O emissions, and soil ammonium N content and nitrate N content affect soil N₂O flux, i.e., higher soil ammonium N content is associated with higher soil N₂O flux, while higher soil nitrate N content is associated with lower soil N₂O flux.

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Objective To determine the relationships between maturity, Na⁺, small molecular organic acids of product of kitchen waste biochemical equipment and germination index (GI), promote the resource utilization and popularization of the product of kitchen waste biochemical equipment, and at the same time, exploit the new technological way of carbon neutrality through soil carbon sequestration. Method The GI of product of kitchen waste biochemical equipment was determined using radish (Raphanus sativus) seeds, and the effects of Na⁺ and small molecular organic acid solutions on GI were analyzed by mimic experiments. Result The GI of the kitchen waste biochemical equipment product was 1.53%, which did not reach the standard of basic maturity of compost (GI ≥ 50%). When the extract of kitchen waste biochemical equipment product was diluted for 10 times, the Na⁺ content in the solution was 75.25 mg/L, and the GI value was 43.73%. With the increase of sodium concentration, the GI value showed a downward trend. When the Na⁺ concentration was 1 200 mg/L, the GI value was 52.86%. With the increase of the concentration of small molecular organic acids, the GI value showed a downward trend. When the concentrations of acetic acid and lactic acid were higher than 100 mg/L, and while the concentrations of propionic acid and butyric acid were higher than 50 mg/L, the GI value was less than 50%. The inhibiting effect of propionic acid and butyric acid on GI was stronger than that of acetic acid and lactic acid. Conclusion The GI of product of kitchen waste biochemical equipment did not reach the maturity standard of composting, and the main restriction factor was the small molecular organic acids produced by the degradation of kitchen waste, rather than its salt content.

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Objective The purpose of this study was to comprehensively evaluate the differences in fruit quality among different guava (Psidium guajava) cultivars and explore key genes for flavonoid synthesis. Method A total of 11 fruit quality indexes of six guava cultivars were measured and principal component analysis was carried out. Transcriptome sequencing technology was used to compare the differentially expressed genes (DEGs) among the cultivars, and GO and KEGG enrichment analyses were carried out to mine the DEGs of flavonoid synthesis. Quantitative real-time PCR (qRT-PCR) was used to study the specific expression of differential genes in different cultivars. Result Among the six guava cultivars, ‘Jindouxiang’ and ‘Yanzhihong’ scored higher, ‘Shuijing’ and ‘Xiguahong’ scored lower, and ‘Zhenzhu’ and ‘Hongbaoshi’ scored in the middle. The flavonoid contents of ‘Jindouxiang’ and ‘Yanzhihong’ were significantly higher compared to other cultivars (P>0.05), which were 9.76 and 10.05 mg/g, respectively, more than 1.5 times that of ‘Shuijing’ (5.74 mg/g). Transcriptome sequencing analysis showed that the DEGs of ‘Jindouxiang’ and ‘Yanzhihong’ were clustered into one category, and the DEGs of the other four cultivars were clustered into one category. CHS, FLS, CYP73A, CYP98A3, DFR, E2.1.1.104, E1.14.11.19 and CYP75A genes in the biosynthetic pathway of flavonoids were significantly up-regulated in ‘Jindouxiang’ and ‘Yanzhihong’. qRT-PCR verification showed that the expression of FLS gene was the highest in ‘Yanzhihong’, which was more than 10 times of that in ‘Xiguahong’. The expression levels of CYP73A, CYP75A, E2.1.1.104 and CHS genes were the highest in ‘Jindouxiang’ and the lowest in ‘Zhenzhu’. Among them, the expression levels of CYP73A and CYP75A genes in ‘Jindouxiang’ were more than 30 times of those in ‘Zhenzhu’, while the expression level of DFR gene was higher in ‘Yanzhihong’ and lower in ‘Jindouxiang’. The expression levels of DEGs were consistent comparing the qRT-PCR and transcriptome sequencing results, indicating the transcriptome sequencing results of six guava cultivars were reliable. Conclusion The quality differences of six guava cultivars were systematically evaluated, and eight key genes related to the synthesis of guava flavonoids were discovered. This study provides a scientific basis for the research of guava cultivar breeding, functional gene mining and biosynthetic pathway of flavonoids.

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Objective The aim of this paper was to analyze and predict the potential suitable regions of Emex australis in China and the major environmental variables affecting its distribution, and provide a theoretical reference for the prevention of the invasion of E. australis into China and protection of the agricultural production and ecological security.Method The Jackknife was used to calculate the influence of each environmental variable on the species distribution. ENMeval was used to optimize the maximum entropy model (MaxEnt). Then the optimized model was used to predict the potential suitable region of E. australis in China by inputting the distribution data of E. australis and the climate data under different climate scenarios. Result The main factor affected the distribution of E. australis was the mean temperature of the coldest month (Bio11), with a contribution rate of 27.7%. The environmental factor response curves showed that the emergence probability of E. australis was greater than 0.5, when the mean temperature of the coldest quarter ranged from 9.35 to 12.76 ℃. Results of the MaxEnt model showed that the suitable regions of E. australis in China were mainly in Yunnan, Guangdong, Guangxi and Fujian. Conclusion A normalized monitoring scheme should be established for the suitable area of E. australis. In the years when the mean temperature of the coldest quarter in the suitable region is good for its survival, monitoring efforts should be strengthened to prevent its colonization and distribution in China.

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Objective The present study aimed to screen and isolate the antagonistic fungal strains with strong control effect against fusarium wilt from rhizosphere soil of Saposhnikovia divaricata.Method The strain MR-97, which was antagonistic to Fusarium oxysporum, was isolated from the rhizosphere soil of S. divaricata by confrontation culture method, and its bacteriostatic spectrum was determined. The strain was identified by fungal colony characteristics, microscopic characteristics and ITS sequence analysis. The effect of strain MR-97 on hyphae growth of pathogenic fungus were recorded by microscopic examination. The colonization ability of strain MR-97 in the soil was evaluated by antibiotic marker method. The control effect of strain MR-97 on fusarium wilt of S. divaricata were evaluated by pot experiment in the field. Result The antagonistic strain MR-97 was screened with antibacterial rate of 64.44% against F. oxysporum. It also had strong antibacterial effect against eight common pathogens including F. equiseti and Botrytis cinerea, etc. The strain MR-97 was identified as Aspergillus terreus. The hyphal of pathogen enlargement, malformation, damage and agglutinated with inclusions, etc. when the strain MR-97 and F. oxysporum were cultured in confrontation. It had a good colonization effect in the soil, and the highest content of soil bacteria was 9.8×10⁶ CFU/g. The biocontrol effect of MR-97 on fusarium wilt of S. divaricata was 67.86% in pot experiment, which had good control efficiency. Conclusion Aspergillus terrestris MR-97 can effectively inhibit the mycelia growth of F. oxysporum and other pathogens, can colonize quickly in soil and has strong biocontrol effect. MR-97 strain, as a good source of biocontrol bacteria, has certain potentials of development and utilization.

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Objective To clarify the pathogen causing Trichosanthes kirilowii fruit rot and screen effective fungicides for controlling the disease. Method Samples of rot fruit from T. kirilowii plants were collected from Dabie Mountain Areas, Anhui Province in 2019—2020. A total of 35 representative isolates were obtained by tissue isolation. The pathogenicity was verified according to the Koch’s postulate, and the causal agents were identified based on the morphological characteristics and multilocus sequence analysis. The indoor toxicity of seven fungicides against the pathogen was detected by the mycelium growth rate method. Result Colonies with four different morphological characteristics were isolated and purified. The isolates were confirmed to be pathogenic to the fruit of T. kirilowii according to the Koch’s postulate. They were identified as Fusarium fujikuroi, F. proliferatum, Colletotrichum fructicola and C. liaoningense by combining morphological characteristics with phylogenetic analysis, with isolation frequencies of 31.4%, 8.6%, 20.0% and 40.0%, respectively. In addition, the indoor toxicity test results indicated that prochloraz, fludioxonil, difenoconazole, phenamacril and chlorothalonil had better inhibitory effect against F. fujikuroi and F. proliferatum, with EC₅₀ ranging from 0.1046 to 5.1781 μg/mL. Prochloraz, fludioxonil and difenoconazole had better inhibitory effect against C. fructiicola and C. liaoningense with EC₅₀ ranging from 0.0097 to 2.1325 μg/mL. Conclusion The causal agents associated with fruit rot disease on T. kirilowii are Fusarium spp. and Colletotrichum spp.. Prochloraz, fludioxonil and difenoconazole all show good inhibitory activity against the pathogens.

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Objective The existing position and extraction method of antifungal substance produced by Chaetomium subaffine strain LB-1 were studied in order to lay a foundation for the development of the strain LB-1 to control plant diseases.Method With Botrytis cinerea and Exserohilum turcicum as test plant pathogens, the sealed plate assay was used to detect whether the strain LB-1 could produce volatile antifungal substance. The hyphae ultrasonic breaking and liquid culture methods were used to detect the existing position of nonvolatile antifungal substance produced by the strain LB-1. The extraction method of antifungal substance was determined by detecting the inhibitory effects of ammonium sulfate precipitation, hydrochloric acid precipitation and organic solvents extracts of strain LB-1 culture broth via poison plate assay and filter paper disc assay.Result The strain LB-1 did not have obvious inhibitory effect on the growth of the two test plant pathogens when being co-cultured in a sealed plate with each plant pathogen, indicating that strain LB-1 could not produce volatile antifungal substance. The antifungal activity of the intracellular extract of the strain LB-1 was not different from that of the control, but its culture broth had a strong inhibitory effect on B. cinerea and E. turcicum, indicating that the antifungal substances produced by the strain LB-1 existed outside the mycelium. Neither ammonium sulfate precipitate nor hydrochloric acid precipitate of strain LB-1 culture broth showed inhibitory effect on B. cinerea and E. turcicum, but the organic solvent extract of strain LB-1 culture broth showed antifungal effect, and the inhibition rate of n-butanol extract was the highest. When the concentration was 0.1 mg/mL, the inhibition rates against B. cinerea and E. turcicum growth were 59.80% and 58.37% respectively.Conclusion The strain LB-1 inhibited the growth of plant pathogenic fungi by producing extracellular nonvolatile antifungal substances, and the antifungal substance in the culture broth can be extracted by n-butanol.

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Objective To understand the community composition and diversity of birds in Qingyunshan Provincial Nature Reserve, Wengyuan, Guangdong.Method In 2021, this study used line transect method to conduct field surveys of bird communities in four habitats of forest, highway, village, and reservoir in Qingyunshan Reserve, while interviewing local residents and reserve staff, looking up reserve basic information and scientific expedition reports, and searching for the records of China National Knowledge Infrastructure (CNKI) and China Bird Reports Center, etc.Result A total of 168 species of birds in 17 orders and 51 families were counted. Statistics of the faunal types showed that there were 103 oriental birds, 40 widely distributed birds, and 25 palaearctic birds. The result of residence type classification suggested that there were 119 species of resident birds, 43 species of visitor birds (27 species of winter visitor birds and 16 species of summer visitor birds), and 6 species of passage migrant birds. The ecotype was dominated by the songbirds, and the diet habit was dominated by omnivorous and insectivorous. The dominant species included Alcippe hueti, Hemixos castanonotus and Pericrocotus speciosus. Of all the detected species, two species were listed as first-class National Protected Wildlife and 30 species were listed as second-class National Protected Wildlife. The avian average biomass declined in order of forest, village, reservoir and highway respectively. The diversity index analysis showed that the highest Shannon-wiener diversity index (3.24) and Pielou evenness index (0.61) were in the village habitat; The highest Margalef richness index (7.34) was in the highway habitat; The village and highway habitats tied for the highest Simpson dominance index (0.94).Conclusion With rich vegetation and diverse habitats, Guangdong Wengyuan Qingyunshan Provincial Nature Reserve provides abundant food resources and suitable space for birds to survive and breed. With the succession of vegetation and the enhancement of environmental awareness amongst the pubilc, the reserve still has great potential in bird diversity conservation.

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Objective A large amount of particulate matter, absorbed odor components and microorganisms discharged from livestock and poultry houses will cause serious damage to the atmospheric environment and health of surrounding person. Reducing the concentration of particulate matter in emissions is one of the core objectives of the emission purification technology at the end of livestock and poultry houses. Method This paper focused on the particulate matter removal performance of the horizontal water spray purification technology at the end of livestock and poultry houses. An orthogonal test scheme was designed and carried out on a self-built horizontal water spray system particle purification efficiency test platform. The range analysis and variance analysis methods were employed to analyze the influence of key control parameters such as ventilation air speed, nozzle pressure, nozzle rated orifice diameter and nozzle atomization angle on the purification efficiency of PM2.5 and PM10 particles, and the optimal control parameter combination for different particle size was obtained using a parameter optimization model. Result The results showed that the order of the control parameters affecting PM2.5 purification efficiency was nozzle pressure>ventilation air speed>nozzle rated orifice diameter>nozzle atomization angle; And the order of the control parameters affecting PM10 purification efficiency was nozzle pressure>nozzle rated orifice diameter>nozzle atomization angle>ventilation air speed. According to the optimized solution, the optimal control parameter combination was that the ventilation speed was 1.5 m/s, the nozzle pressure was 60 kPa, the rated nozzle orifice diameter was 11.1 mm, and the nozzle atomization angle was 120°. The results of validation test showed that the purification efficiencies of PM10 and and PM2.5 of the optimal control parameter combination were 40.4% and 41.1% respectively. Conclusion The findings can provide a reference for the design and operation parameter regulation of particulate matter purification equipment at the end of livestock and poultry houses.

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Objective There are problems of missed seeding and reseeding during the operation of cotton hole sowing machine used in Xinjiang region, which the driver could not find in time. A real-time monitoring system for cotton sowing quality was designed to solve these problems.Method The monitoring system uses the STM32F103C8T6 microcontroller hardware system as the lower computer, obtains the information of missed seeding and reseeding of cotton seeds through the counter-light photoelectric sensor and photoelectric encoder installed on the seed storage ring of the hole sower, and determines the quality of cotton sowing. The cotton sowing information is transmitted to the human-machine interface of the DWIN touch screen through the nRF24L01 module for real-time display. A test bed of cotton sowing quality monitoring system was built to verify the accuracy of the monitoring system through field tests.Result The results of the bench test showed that the system had the highest monitoring accuracies of 96.65%, 94.59% and 92.00% respectively for qualified seeding, missed seeding and reseeding when the speed of the hole sower was 30 r/min. When the speed of the hole sower was higher than 30 r/min, the monitoring accuracy decreased obviously. The results of field trial validation showed that the average monitoring accuracies of the system were 94.51%, 92.38% and 86.55% respectively for qualified seeding, missed seeding and reseeding. The analysis of the field trial data using SPSS software concluded that the trial data were statistically significant, and the cotton sowing quality data obtained by the monitoring system had a high correlation with the manually measured data, and the actual values could be reflected by the system monitoring values.Conclusion The system meets the demand for monitoring the quality of cotton sowing in field operation, and is of great significance for realizing the improvement of quality and efficiency of cotton planting.

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Objective The wetting behavior of the front and back surfaces of banana leaves at different growth stages of the banana tree canopy was studied, in order to provide a basis for the regulation mechanism of pesticide droplets retention on the surface of banana leaves. Method The static wetting properties of the banana leaf surface were characterized by a contact angle measuring instrument, the dynamic wetting behavior of droplets on the surface of the banana leaf was recorded by a high-speed camera, and the structural information of the banana leaf surface was observed by a field emission scanning electron microscope. The surface chemical composition was analyzed using the Fourier transform infrared spectrometer. The surface microstructure model of banana leaf was constructed based on the Wenzel and Cassie wetting theory, and the wetting equation was established to describe its wetting mechanism. Result Scanning electron microscopic observation showed that the front surface of banana leaves presented a micro-nano-scale double-layer composite structure, the micro-scale protrusion structure was covered with nano-scale papillary structures with a density of about 4.6 pieces/μm², the strip-like protrusion width was (16.03±3.48) μm, the average diameter of papillae was (0.116±0.068) μm, the size of micron-scale strip-like protrusions on the back of banana leaves was larger than that of the front, and the width was (74.25±9.80) μm, the nano-scale structure had mesh-like protrusions with a width of (2.35±0.49) μm, and the wettability of the back of banana leaves was generally higher than that of the front. For banana leaves at different growth stages, the front of flag leaves showed hydrophilicity with contact angle of 71.46°±6.02°, while the front and back of banana leaves at other stages showed weak hydrophobicity, indicating that the front surface of young leaves had stronger wetting and spreading ability. By constructing the Wenzel and Cassie wetting models for the front surface of mature banana leaves, the intrinsic contact angle of the front surface of mature banana leaves was 20.76° showed super-hydrophilic based on analysis and calculation, indicating that its nano-scale papillary structure was polysaccharide. Conclusion The combination of the hydrophobic micro-nano bilayer composite structure and the hydrophilic chemical components on the surface of banana leaves leads to the wet state of weak hydrophobicity on the surface, and the polysaccharide of the nano-papillary structure is responsible for hydrophilic effect and high adhesion effect of the banana leaf surface.

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Objective To study the effect of magnetization on surface tension of herbicide solution and particle size of herbicide spray droplet, and explore a new control method of particle size of herbicide spray droplet.Method The surface tension experiment of the magnetized herbicide solution and the particle size experiment of the magnetized spray droplet were designed to record the surface tension value of the herbicide solution and the particle size value of the spray droplet under the influence of two factors of different magnetic field intensity and magnetization duration, observe the change rule of the data, and fit the data, and give the functional relationship that conforms to the description of the data change.Result When the magnetic field intensity was 50−500 mT and magnetization duration was 5.0−25.0 min, both the surface tension of solution and the particle size of spray droplet decreased firstly and then rose with the increase of magnetic field intensity and magnetization duration. When the magnetic field intensity was 350 mT and magnetization duration was 15.0 min, the surface tension and particle size of spray droplet decreased the most. The surface tension value decreased to 54.0 mN/m with a drop rate of 14.96%, and the spray droplet size decreased to 108.75 μm with a drop rate of 11.20%. For surface tension data, the determination coefficient (R²) of Lorentz fitting function was 0.816 4, adjusted R² was 0.794 0, root mean square error (RMSE) was 1.105 9; And the R² of polynomial fitting function for spray droplet size data was 0.833 6, adjusted R² was 0.787 4, RMSE was 2.085 7. The fitting function was meaningful and the fitting precision was high. Conclusion It is not that the magnetization effect will be better with the increase of magnetic field intensity or magnetization duration, but that the optimal magnetization intensity and duration exist. The Lorentz model function given in this paper can be used as the function relation between the surface tension of herbicide solution and magnetization, and the cubic polynomial function can be used as the model for controlling the particle size of fog droplets under the magnetic field intensity of 350 mT.