Forest biomass resources and utilization in China

Under the context of climate change, persistent high oil prices and rapidly growing dependence on imported oil prompt China to pay much more attention to biofuels that provide environmental benefits besides fuel. China has rich biodiversity with 30 thousand high plant species and 154 kinds of energy trees could produce seeds containing more than 40% of oil, with total production of the seeds totaling 5 million t, and 200 x109 t of biomass production per year, which is equal to 2 x 109 t of petroleum. There are over 2000 types of wild and cultivated firewood plants in the country. So far there is 4 million ha raising oil-bearing trees planted on some land in different regions. Another 57 million ha of waste land are available and suitable for planting trees for the production of forest bioenergy. On part of these lands, the central government plans to cultivate a total of 13 million ha of high-grade bioenergy forests by 2020. This will yield 6 million tons of diesel that would be enough to fuel power plants with a combined capacity of 11 GW each year. Moreover, forest biomass plantations potentially offer many direct and indirect environmental benefits. In view of climate change their globally significant environmental benefits may result from using forest biomass for energy rather than fossil fuels.Key words: Biomass energy, China, forest biomass resources

Experimental investigations of stress-gas pressure evolution rules of coal and gas outburst: A case study in Dingji coal mine, China

Coal and gas outburst is a potentially fatal risk during the mining of gassy coal seams, which seriously threatens the safe mining of collieries. To understand the outburst mechanism and evolution rules, a new apparatus (LSTT) was developed to conduct simulated experiment. In the context of an outburst accident in Dingji coal mine, the authors launched an authentic outburst experiment to replay the outburst accident. Experimental apparatus, similar criterion, coal‐like materials and gas sources, and experimental design were discussed systematically in this paper. Experimentally, the study analyzed the geo‐stress has significant influence on the outburst evolution. At the driving face, the stress concentration possibly caused gas outburst, under the influence of mining‐induced stress. After the outburst occurred, the stress balance of the coal changed, resulting in the instability of the coal. Furthermore, the elastic energy, gas enthalpy, and gravitational potential energy were released rapidly. The experimental result stated that outburst coal has the sorting characteristics, in line with the field outburst law. The intensity prediction model has been built based on the energy model. Moreover, the factors that impact outburst intensity were analyzed. In the process of coal and gas outburst, the gas enthalpy of gas and the elastic potential of coal are the main energy sources. This study provides guidance for the development of the outburst mechanism and outburst mine management

Effects of two-week machine massage on muscle properties in adolescent wrestlers

Objective: This study aimed to investigate the effect of a two-week machine massage on the physical properties of the erector spinae and serum biochemical indexes of adolescent athletes after training.Methods: Sixteen male adolescent wrestlers were recruited (age: 15 ± 1 year; height: 166 ± 7 cm; weight: 56 ± 7 kg) and randomly assigned to machine massage (MA, 8) and control (CO, 8) groups. Participants in the MA group received machine massage for 20 min after each wrestling training from Monday to Saturday (except on Thursday) for two weeks, while the participants in the CO group recovered naturally. Over the course of two weeks, all the participants underwent similar wrestling training program under the guidance of a professional coach. Before and after the intervention, serum urea and creatine kinase (CK) levels were measured in a fasting state. A Myoton Pro digital muscle evaluation system was used to measure the physical properties of the erector spinae, including the oscillation frequency, logarithmic decrement of a muscle’s natural oscillation, and dynamic stiffness.Results: After two weeks of machine massage treatment, the dynamic stiffness of the erector spinae in the MA group decreased by 12.90% and that in the CO group increased by 2.34%, indicating a significant difference between the two groups (p = 0.04, ƞ2 = 0.286). The decrease in the logarithmic decrement of a muscle’s natural oscillation value in the MA was significantly greater than that in the CO (p = 0.003, ƞ2 = 0.286). Moreover, the serum CK values decreased by 33.84% in the MA group and by 1.49% in the CO group, despite a trend of change between the groups (p = 0.062, ƞ2 = 0.084). No significant difference was found in the improvement in serum urea levels between the two groups after two weeks of treatment.Conclusion: Results of the present study indicated that a two-week machine massage had a positive effect on the improvement of the physical properties of the erector spinae of wrestlers during training

Review of environmental fate of chiral antibiotics in the vadose zone

To date, the systematic summarization and comprehensive review of analysis, distribution, migration, and degradation of chiral antibiotics in the vadose zone are limited. This review indicates that the physicochemical characteristics of chiral antibiotics are quite different, for instance, the solubility and octanol-water partition coefficient (lg Kow) of S-gemifloxacin are 301 times and 9.8 times larger than the values of R-gemifloxacin, which will affect their migration and degradation in the environment. High performance liquid chromatography with chiral column and chiral ligand-exchange chromatography are the common methods on the chiral antibiotics analysis. The concentrations of chiral antibiotics in soils, waters, and agricultural products in China and abroad are reported; flumequine, lomefloxacin and ofloxacin are the most common antibiotics. The adsorption rate and partition coefficient (Kd) of chiral antibiotics during their adsorption on minerals and microplastics are different, especially in the presence of natural organic matter (NOM); however, there is no relationship among the various types of chiral antibiotics. Chiral antibiotics can be complexed with the common cations, and their stability constants are quite different in the groundwater, for instance, the stability constant of Mg2+-levofloxacin is 22.9 times larger than that of Mg2+-ofloxacin. During the biodegradation process, the degradability and rate of chiral antibiotics are also different. Additionally, the chiral antibiotics can be transformed reciprocally. In this review, the distribution, migration, and degradation of chiral antibiotics in the vadose zone are investigated, which is beneficial to the study on the chiral antibiotics in the groundwater. As to the environmental fate of chiral antibiotics in the vadose zone, the following researches are recommended: (1) the resolution, analysis, toxicology, and standard establishment of chiral antibiotics; (2) the investigation, migration, and degradation of multiple chiral antibiotics; (3) the environmental processes of chiral antibiotics in the multi-interface

Genome mining reveals the prevalence and extensive diversity of toxin–antitoxin systems in Staphylococcus aureus

IntroductionStaphylococcus aureus (S. aureus) is a highly pathogenic and adaptable Gram-positive bacterium that exhibits persistence in various environments. The toxin-antitoxin (TA) system plays a crucial role in the defense mechanism of bacterial pathogens, allowing them to survive in stressful conditions. While TA systems in clinical pathogens have been extensively studied, there is limited knowledge regarding the diversity and evolutionary complexities of TA systems in S. aureus.MethodsWe conducted a comprehensive in silico survey using 621 publicly available S. aureus isolates. We employed bioinformatic search and prediction tools, including SLING, TADB2.0, and TASmania, to identify TA systems within the genomes of S. aureus.ResultsOur analysis revealed a median of seven TA systems per genome, with three type II TA groups (HD, HD_3, and YoeB) being present in over 80% of the strains. Additionally, we observed that TA genes were predominantly encoded in the chromosomal DNA, with some TA systems also found within the Staphylococcal Cassette Chromosomal mec (SCCmec) genomic islands.DiscussionThis study provides a comprehensive overview of the diversity and prevalence of TA systems in S. aureus. The findings enhance our understanding of these putative TA genes and their potential implications in S. aureus ecology and disease management. Moreover, this knowledge could guide the development of novel antimicrobial strategies