Extracts are important components of fuels. Fatty-extracts with high heating value （HV） are hypothe- sized by researchers as positively related to the HV of fuels. The Soxhlet extractor is typically used to extract ...Extracts are important components of fuels. Fatty-extracts with high heating value （HV） are hypothe- sized by researchers as positively related to the HV of fuels. The Soxhlet extractor is typically used to extract fatty-extracts but it has shortcomings, including long processing time （8-10 h） and the requirement for large amounts of organic solvent. Supercritical extraction is an alternate and useful technique for extraction of natural products. However, published studies rarely discuss the relationship between extracts and HV. In this study, we assessed the supercritical extracts （SUE） of forest fuels in the Great Xing＇an Mountains. Our results indicated that the optimum conditions for extraction of SuEs were 40-60 mesh, 40-50 MPa, 45℃, 80 min and a CO2 flow rate of 1.5-2.0 dm3/min. The Soxhlet extracts contents and the SuE contents were all related to HV. However, R2 of the coniferous samples （0.8499） and needle samples （0.9722） demonstrated that the correlation between HV and the SuE content was closer. We conclude that supercritical fatty-extracts provide a useful index of the HV of fuels, especially coniferous fuels. SuE data can be used in fire management, for example to estimate the rate of fire spread or fire intensity.展开更多
Fungal pathogens causing poplar canker diseases are cosmopolitan in species,and have a wide range of hosts.These pathogens have diverse anamorphs and their morphology overlaps with each other;Their teleomorphs are har...Fungal pathogens causing poplar canker diseases are cosmopolitan in species,and have a wide range of hosts.These pathogens have diverse anamorphs and their morphology overlaps with each other;Their teleomorphs are hardly discovered in nature.Furthermore,the identification of these pathogens is usually limited by the geography,host and taxonomic knowledge.Therefore,a culture-independent method used to identify determine pathogens is expected to be developed for field diagnostics.Through amplifying,sequencing and analyzing multiplex nucleic acid templates and genetic marked target sequences,a multiplex PCR technique has been established and used to directly detect various environmental samples.In this study, four pathogen strains and environmental samples were amplified using fungal universal primers ITS1/ ITS4 and EF1-728F/EF1-986R by general PCR and multiplex PCR.The amplicons were sequenced,and then aligned in GenBank.The result showed that the multiplex PCR was able to successfully amplify the target gene and identify the pathogens from environmental samples in the condition of an annealing temperature of 55.6℃and primers final concentration of 0.2μmol·L<sup>-1</sup>.The multiplex PCR could amplify the target at the concentration level of approximately lng of genomic DNA.This method would provide a useful tool for the identification of canker pathogens by the multiplex PCR and the high-throughput DNA microarray detection of environmental samples.展开更多
基金sponsored by the National Natural Science Foundation of China(Grant number:31170618)the National Key Technologies R&D Program of China(Grant number2011BAD32B05)
文摘Extracts are important components of fuels. Fatty-extracts with high heating value （HV） are hypothe- sized by researchers as positively related to the HV of fuels. The Soxhlet extractor is typically used to extract fatty-extracts but it has shortcomings, including long processing time （8-10 h） and the requirement for large amounts of organic solvent. Supercritical extraction is an alternate and useful technique for extraction of natural products. However, published studies rarely discuss the relationship between extracts and HV. In this study, we assessed the supercritical extracts （SUE） of forest fuels in the Great Xing＇an Mountains. Our results indicated that the optimum conditions for extraction of SuEs were 40-60 mesh, 40-50 MPa, 45℃, 80 min and a CO2 flow rate of 1.5-2.0 dm3/min. The Soxhlet extracts contents and the SuE contents were all related to HV. However, R2 of the coniferous samples （0.8499） and needle samples （0.9722） demonstrated that the correlation between HV and the SuE content was closer. We conclude that supercritical fatty-extracts provide a useful index of the HV of fuels, especially coniferous fuels. SuE data can be used in fire management, for example to estimate the rate of fire spread or fire intensity.
文摘Fungal pathogens causing poplar canker diseases are cosmopolitan in species,and have a wide range of hosts.These pathogens have diverse anamorphs and their morphology overlaps with each other;Their teleomorphs are hardly discovered in nature.Furthermore,the identification of these pathogens is usually limited by the geography,host and taxonomic knowledge.Therefore,a culture-independent method used to identify determine pathogens is expected to be developed for field diagnostics.Through amplifying,sequencing and analyzing multiplex nucleic acid templates and genetic marked target sequences,a multiplex PCR technique has been established and used to directly detect various environmental samples.In this study, four pathogen strains and environmental samples were amplified using fungal universal primers ITS1/ ITS4 and EF1-728F/EF1-986R by general PCR and multiplex PCR.The amplicons were sequenced,and then aligned in GenBank.The result showed that the multiplex PCR was able to successfully amplify the target gene and identify the pathogens from environmental samples in the condition of an annealing temperature of 55.6℃and primers final concentration of 0.2μmol·L<sup>-1</sup>.The multiplex PCR could amplify the target at the concentration level of approximately lng of genomic DNA.This method would provide a useful tool for the identification of canker pathogens by the multiplex PCR and the high-throughput DNA microarray detection of environmental samples.
