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As a key parameter, the particle size of residual coal contributes greatly to its oxidation characteristics, so it is a significant and far-reaching topic to explore the role of different particle sizes in coal spontaneous combustion disaster. In this work, temperature-programmed system (TPS) was applied to analyze the oxygen consumption rate and CO and C2H4 production rules of six groups of coal samples with different particle sizes in the process of oxidation heating. The critical temperature (CT) and xerochasy temperature (XT) of different coal samples were obtained, and the coal oxidation process was divided into three stages (S1, slow oxidation stage; S2, fast oxidation stage; and S3, combustion stage). Then, the apparent activation energy (E) and pre-exponential factor (A) in three stages were regressed combined with Arrhenius formula. The results show that the smaller the coal particle size is, the larger the specific surface area is, the stronger the adsorption capacity of coal molecules and oxygen molecules is, resulting in the larger oxygen consumption rate. The values of CT and XT with particle size of 0.125–0.18 mm and 2–4 mm are the smallest and largest. For coal samples with the same particle size, the maximum values of E and A occur in stage S3 and the minimum values appear in stage S1. This is mainly due to the higher temperature of stage S3, which allows the activation of functional groups with higher apparent activation energy, stronger collisions between activated molecules, and more intense oxidation reactions.

Stress is one of the main factors influencing coal and gas outbursts. The apparent effects of the crustal stress, the structural stress, and the mining-induced stress increase as the depth of mining increases. At present, there have been few studies of the relationship between the comprehensive analyses of the crustal stress, mining-induced stress, and coal gas. The in situ measurement of the relationship between stress-related behaviors and coal gas under the influence of mining was conducted through experimental analysis of surrounding rock support and coal and gas outburst control and optimization of surrounding rock support materials and system construction. The results showed that the mining-induced stress first increased to a peak value, then gradually decreased, and tended to stabilize as the footage progresses. Stress appears at 96 m ahead due to mining; after 57 m of advancing, there is a large increase until it passes through this area. The stress in front of the working face increases linearly, and the increase range is obviously larger than that of the coal body in a certain range on both sides. The support anchoring force gradually decreased and tended to be stable after rapidly increasing to a maximum value. The deep displacement of the roof increased linearly and tended to be stable after reaching an accumulated displacement which can reach 16-28 mm. The residual gas pressure in front of mining operations decreased rapidly, and beyond 15 m on each side of the roadway, it decreased significantly. The residual gas pressure and gas content were consistent with the gas desorption index of drill cuttings due to the influences of gas predrainage and mining. The stress along the direction of the roadway and the residual gas content, the residual gas pressure, and the gas desorption index of drill cuttings conform to the logarithmic functional relationship. The research results provide a basis for the comprehensive prevention and control of coal and gas outbursts from multiple angles considering stress, coal, and gas.

Based on the principle of gas formation on the coal mining work surface, the article analyzes the main source of gas in the mining area of Dashe coal mine, finds out all kinds of problems existing in the pumping of the upper angle intring tube, and summarizes the real reasons for the backwind of the work surface and the gas exceeding the limit of the upper angle. In view of these reasons, combined with the principle of the formation of the upper angle gas, the mine on the upper angle intring process construction of the intring depth, height and interception area of the investigation, to obtain the best pumping value under different conditions, and according to the results of the inspection in the 21704 work surface test and transformation, and achieved a better pumping effect; According to the test results, the field effectively controls the work surface and the upper angle gas exceeding the limit, ensures the safe production of the work surface and the mine, and provides reference and reference for the treatment of the angle gas on the work surface under the same type of condition.

Actinomycetes are important producers of antibiotics and other important bioactive substances. Extraordinary ecosystems cause the evolution of novel secondary metabolic pathways of Actinomycetes, and increase the discovery possibility of new biological functions of bioactive compounds. Here, we isolated a rare Actinomycete from the soil samples of Cactus rhizosphere. An antagonistic Actinomycete strain (named SCA3-4) was screened against Fusarium oxysporum f. sp. cubense Tropical Race 4 (Foc TR4, ATCC 76255). The strain produced Pink-white aerial mycelia and brown substrate mycelium on gause No. 1 agar. Biverticillate chains of cylindrical spores were detected by scanning electron microscope (SEC). Analysis of the 16S rRNA sequence and a phylogenetic tree exhibited that the SCA3-4 strain shared a 99.54% similarity with Streptoverticillium lilacinum NRRL B-1968T and clustered into the same branch. Based on morphological, biochemical, physiological and molecular characteristics, the SCA3-4 strain was identified as Streptoverticillium sp. It can grow well on the different antibiotic medium with chloramphenicol, streptomycin, penicilin-G, gentamicin, erythromycin or neomycin sulfate. The PCR amplification of type I and Ⅱ polyketide synthase genes (PKS-I and PKS-Ⅱ) supported that the SCA3-4 strain owned the possible antimicrobial activity. Ethyl acetate extracts of the SCA3-4 strain showed a broad-spectrum antifungal activity against 13 plant pathogenic fungi including Foc TR4 and F. oxysporum f. sp. Cubense race 1 (ACCC 31271). The results of transmission electron microscope (TEM) showed that the crude extracts at the concentration 100 μg/ml inhibited spore germination and growth of Foc TR4 fungal spores by destroying cell membrane. 21 different compounds were identified from ethyl acetate extract of SCA3-4 strain by Gas Chromatography-Mass Spectrometry (GC-MS). These compounds were comprised of phenolic compound, pyrrolizidine, hydrocarbons, esters, and acids. Some compounds were already reported to possess antimicrobial or other biological activities. Other compounds with no functional annotation will be paid more and more attention to the discovery of new bioactive substances in the future.

MicroRNAs (miRNAs) represent a class of endogenous non-coding small RNAs that play important roles in multiple biological processes by degrading targeted mRNAs or repressing mRNA translation. Thousands of miRNAs have been identified in many plant species, whereas only a limited number of miRNAs have been predicted in M. acuminata (A genome) and M. balbisiana (B genome). Here, previously known plant miRNAs were BLASTed against the Expressed Sequence Tag (EST) and Genomic Survey Sequence (GSS), a database of banana genes. A total of 32 potential miRNAs belonging to 13 miRNAs families were detected using a range of filtering criteria. 244 miRNA:target pairs were subsequently predicted, most of which encode transcription factors or enzymes that participate in the regulation of development, growth, metabolism, and other physiological processes. In order to validate the predicted miRNAs and the mutual relationship between miRNAs and their target genes, qRT-PCR was applied to detect the tissue-specific expression levels of 12 putative miRNAs and 6 target genes in roots, leaves, flowers, and fruits. This study provides some important information about banana pre-miRNAs, mature miRNAs, and miRNA target genes and these findings can be applied to future research of miRNA functions.

The metastable zone for a nylon 12-toluene solution was determined in an established constant cooling rate apparatus. Supersaturation solubility curves and the equilibrium solubility curve are unparallel one to another. The metastable zone width under seeded conditions is dependent on the cooling rate, the retention time and the saturation temperature. And the metastable zone width under unseeded conditions is dependent on the cooling rate, the agitation rate and the saturation temperature. Through constant cooling rate crystallization experiments, two empirical correlations pertaining to the metastable zone of the solution have been found.