With the continuous increase of mining in depth,the gas extraction faces the challenges of low permeability,great ground stress,high temperature and large gas pressure in coal seam.The controllable shock wave(CSW),as ...With the continuous increase of mining in depth,the gas extraction faces the challenges of low permeability,great ground stress,high temperature and large gas pressure in coal seam.The controllable shock wave(CSW),as a new method for enhancing permeability of coal seam to improve gas extraction,features in the advantages of high efficiency,eco-friendly,and low cost.In order to better utilize the CSW into gas extraction in coal mine,the mechanism and feasibility of CSW enhanced extraction need to be studied.In this paper,the basic principles,the experimental tests,the mathematical models,and the on-site tests of CSW fracturing coal seams are reviewed,thereby its future research directions are provided.Based on the different media between electrodes,the CSW can be divided into three categories:hydraulic effect,wire explosion and excitation of energetic materials by detonating wire.During the process of propagation and attenuation of the high-energy shock wave in coal,the shock wave and bubble pulsation work together to produce an enhanced permeability effect on the coal seam.The stronger the strength of the CSW is,the more cracks created in the coal is,and the greater the length,width and area of the cracks being.The repeated shock on the coal seam is conducive to the formation of complex network fracture system as well as the reduction of coal seam strength,but excessive shock frequency will also damage the coal structure,resulting in the limited effect of the enhanced gas extraction.Under the influence of ground stress,the crack propagation in coal seam will be restrained.The difference of horizontal principal stress has a significant impact on the shape,propagation direction and connectivity of the CSW induced cracks.The permeability enhancement effect of CSW is affected by the breakage degree of coal seam.The shock wave is absorbed by the broken coal,which may hinder the propagation of CSW,resulting in a poor effect of permeability enhancement.When arranging two adjacent boreholes for CSW permeability enhancement test,the spacing of boreholes should not be too close,which may lead to negative pressure mutual pulling in the early stage of drainage.At present,the accurate method for effectively predicting the CSW permeability enhanced range should be further investigated.展开更多
Coal and gas outburst is a complex dynamic disaster during coal underground mining.Revealing the disaster mechanism is of great signifcance for accurate prediction and prevention of coal and gas outburst.The geo-dynam...Coal and gas outburst is a complex dynamic disaster during coal underground mining.Revealing the disaster mechanism is of great signifcance for accurate prediction and prevention of coal and gas outburst.The geo-dynamic system of coal and gas outburst is proposed.The framework of geo-dynamic system is composed of gassy coal mass,geological dynamic environment and mining disturbance.Equations of stress–damage–seepage interaction for gassy coal mass is constructed to resolve the outburst elimination process by gas extraction with boreholes through layer in foor roadway.The results show the occurrence of outburst is divided into the evolution process of gestation,formation,development and termination of geo-dynamic system.The scale range of outburst occurrence is determined,which provides a spatial basis for the prevention and control of outburst.The formation criterion and instability criterion of coal and gas outburst are established.The formation criterion F1 is defned as the scale of the geo-dynamic system,and the instability criterion F2 is defned as the scale of the outburst geo-body.According to the geo-dynamic system,the elimination mechanism of coal and gas outburst—‘unloading+depressurization’is established,and the gas extraction by boreholes through layer in foor roadway for outburst elimination is given.For the research case,when the gas extraction is 120 days,the gas pressure of the coal seam is reduced to below 0.4 MPa,and the outburst danger is eliminated efectively.展开更多
Ghrelin(ghrl)and its receptor gene ghsr(growth hormone secretagogue receptor)regulate numerous physio-logical functions,including growth hormone secretion and food intake.In the present study,we investigated the seque...Ghrelin(ghrl)and its receptor gene ghsr(growth hormone secretagogue receptor)regulate numerous physio-logical functions,including growth hormone secretion and food intake.In the present study,we investigated the sequences and expression characteristics of these two genes in bighead carp(Hypophthalmichthys nobilis).The ghrl and ghsr genes encoded 106 and 346 amino acids,respectively,and were 1208 bp and 2239 bp in length.Early blastocysts exhibited the highest levels of ghrl and ghsr expression throughout early development(P<0.01).The gut exhibited the highest levels of ghrl expression,whereas significantly higher levels of ghsr(P<0.01)were detected in the brain.Significantly higher levels of ghrl and ghsr expression were detected in the intestine and muscle in summer compared to the levels in winter(P<0.05).Furthermore,the significantly higher levels of ghrl and ghsr expression were detected in the muscle of individuals with big size compared to the levels of individuals with small size(P<0.05).In situ hybridization analyses revealed that the intestine ghrl expression signals were more pronounced than intestinal ghsr expression signals,whereas the ghsr expression signals were more intense than those of ghrl in brain tissues.Finally,the co-expression patterns of related genes in the growth hormone synthesis,secretion,and action pathway(ko04935)and the cAMP signaling pathway(ko04024)indicated that ghrl and ghsr potentially regulate feeding and associated energy metabolism activities in bighead carp,in addition to influencinggrowth performance.展开更多
Capture fisheries and aquaculture provide a significant amount of high-quality protein to human beings and thus play an essential role in ending global hunger and malnutrition.The availability of tens of hundreds of f...Capture fisheries and aquaculture provide a significant amount of high-quality protein to human beings and thus play an essential role in ending global hunger and malnutrition.The availability of tens of hundreds of fish genomes and the advances of genomics have allowed addressing many challenging issues such as overfishing and germplasm degradation faced by fisheries and aquaculture.In this review,we describe the current status of genomics in fisheries and aquaculture,with an emphasis on 14 species of fish that are considerably important to global fisheries and aquaculture,in the context of genome sequencing and assembly,annotation,GC contents,and repeats.The majority of these genomes are assembled at the chromosome level and annotated with proteins and pathways,with functional relevance to fisheries and aquaculture,such as environmental adaptation and phenotypic variation.We summarize potential genomic applications in fisheries and aquaculture that are related to assessment and use of genetic resources,disease resistance,growth and development,sexual determination,and fisheries management.Although much progress has been achieved in genomic application to fisheries and aquaculture,the full potential remains to be explored and reaped.We discuss the challenges and perspectives of genomics in translational aquaculture and fisheries,which include genome assembly and annotation,genomic selection and breeding,genomics in fisheries management,and integrated artificial intelligence systems.In the coming decades,we anticipate the applications of genomic techniques such as genome editing and genomic selection,along with the use of emerging intelligence systems,in aquaculture and fisheries will contribute significantly to genetic improvements of farmed fish and sustainable exploitation of fishery resources,which consequently lead to eradicating global poverty by 2030,an ambitious goal set by the United Nations.展开更多
The CRISPR-Cas9 genome editing has many advantages over its counterparts and could ultimately assist in disease control and molecular breeding in aquaculture.Single-guide RNA(sgRNA)design is presumably the most crucia...The CRISPR-Cas9 genome editing has many advantages over its counterparts and could ultimately assist in disease control and molecular breeding in aquaculture.Single-guide RNA(sgRNA)design is presumably the most crucial task in a typical CRISPR-Cas9 experiment;an understanding of algorithms behind sgRNA design programs is thus essential for improved efficacy and specificity.We focus this review on the bioinformatics aspects in genome editing experiments and describe commonly used computational approaches and tools of sgRNA design and outcome assessment.We show an example of sgRNA design with optimal parameter settings and appropriate interpretation of results and present a brief overview of CRISPR-Cas9 applications,such as genetic improvement and sustainability in aquaculture.We discuss challenging issues,particularly in the context of computational biology,in the use of computational tools in CRISPR-based genome editing.This review provides a synthesis of bioinformatics tools used for CRISPR-Cas9 sgRNA design and outcome assessment and offers a general view of CRISPR-based applications in farmed fish,which are expected to facilitate genome editing programs and hence improve aquaculture breeding,production,and sustainability.展开更多
Injecting external CO_(2) into soft and low-permeability coal seams can improve CH4 extacctinn efficiency, and also benefit in CO_(2) sequestration. However, the distribution law of damage zone around borehole in soft...Injecting external CO_(2) into soft and low-permeability coal seams can improve CH4 extacctinn efficiency, and also benefit in CO_(2) sequestration. However, the distribution law of damage zone around borehole in soft coal seam and its effect on the efficiency of CO_(2) injection promoted CH4 extraction are not clear. In this paper, a multi-physics coupling mathematical model considering damage effect is established for simulating the process of CO_(2) injection promoted CH4 extraction in soft and low-permeability coal seam. The distribution of damage zone and permeability around boreholes under different diameters and coal strengths are analyzed. The gas pressure and gas content in coal seam during CO_(2) injection promoted CH4 extraction when the model considered damage effect are compared with that of ignored. The results show that small borehole diameter corresponds to narrow damage zone around the borehole in coal seam. The damage zone expands with the increase of the borehole diameter. The damage zone increases exponentially with the borehole diameter, while decreases exponentially with the compressive strength of coal seam. The highest permeability in the damage zone has increased by nearly 300 times under the condition of simulated case. CH4 pressure around the extraction borehole reduces, and the reduction area expands with the increase of time. Compared with the result of considering the damage effect, the reduction area of ignoring it is smaller, and the reducing speed is slower. The integrated effect of CO_(2) injection and CH4 extraction leads to rapid decrease of CH4 content in coal seam near the boreholes. The CO_(2) pressure and content increase around the injection borehole, and the increasing area gradually extends to the whole coal seam. In soft coal seams, failure to consider the damage effect will underestimate the efficiency of CH4 extraction and CO_(2) sequestration, resulting conservative layout of boreholes.展开更多
基金National Natural Science Foundation of China(52004117,52174117 and 52074146)Postdoctoral Science Foundation of China(2021T140290 and 2020M680975)Basic scientific research project of Liaoning Provincial Department of Education(JYTZD2023073).
文摘With the continuous increase of mining in depth,the gas extraction faces the challenges of low permeability,great ground stress,high temperature and large gas pressure in coal seam.The controllable shock wave(CSW),as a new method for enhancing permeability of coal seam to improve gas extraction,features in the advantages of high efficiency,eco-friendly,and low cost.In order to better utilize the CSW into gas extraction in coal mine,the mechanism and feasibility of CSW enhanced extraction need to be studied.In this paper,the basic principles,the experimental tests,the mathematical models,and the on-site tests of CSW fracturing coal seams are reviewed,thereby its future research directions are provided.Based on the different media between electrodes,the CSW can be divided into three categories:hydraulic effect,wire explosion and excitation of energetic materials by detonating wire.During the process of propagation and attenuation of the high-energy shock wave in coal,the shock wave and bubble pulsation work together to produce an enhanced permeability effect on the coal seam.The stronger the strength of the CSW is,the more cracks created in the coal is,and the greater the length,width and area of the cracks being.The repeated shock on the coal seam is conducive to the formation of complex network fracture system as well as the reduction of coal seam strength,but excessive shock frequency will also damage the coal structure,resulting in the limited effect of the enhanced gas extraction.Under the influence of ground stress,the crack propagation in coal seam will be restrained.The difference of horizontal principal stress has a significant impact on the shape,propagation direction and connectivity of the CSW induced cracks.The permeability enhancement effect of CSW is affected by the breakage degree of coal seam.The shock wave is absorbed by the broken coal,which may hinder the propagation of CSW,resulting in a poor effect of permeability enhancement.When arranging two adjacent boreholes for CSW permeability enhancement test,the spacing of boreholes should not be too close,which may lead to negative pressure mutual pulling in the early stage of drainage.At present,the accurate method for effectively predicting the CSW permeability enhanced range should be further investigated.
基金supported by the National Natural Science Foundation of China(52004117,52174117 and 51674132)the Postdoctoral Science Foundation of China(2021T140290 and 2020M680975)the Discipline Innovation Team of Liaoning Technical University(LNTU20TD-03 and LNTU20TD-30).
文摘Coal and gas outburst is a complex dynamic disaster during coal underground mining.Revealing the disaster mechanism is of great signifcance for accurate prediction and prevention of coal and gas outburst.The geo-dynamic system of coal and gas outburst is proposed.The framework of geo-dynamic system is composed of gassy coal mass,geological dynamic environment and mining disturbance.Equations of stress–damage–seepage interaction for gassy coal mass is constructed to resolve the outburst elimination process by gas extraction with boreholes through layer in foor roadway.The results show the occurrence of outburst is divided into the evolution process of gestation,formation,development and termination of geo-dynamic system.The scale range of outburst occurrence is determined,which provides a spatial basis for the prevention and control of outburst.The formation criterion and instability criterion of coal and gas outburst are established.The formation criterion F1 is defned as the scale of the geo-dynamic system,and the instability criterion F2 is defned as the scale of the outburst geo-body.According to the geo-dynamic system,the elimination mechanism of coal and gas outburst—‘unloading+depressurization’is established,and the gas extraction by boreholes through layer in foor roadway for outburst elimination is given.For the research case,when the gas extraction is 120 days,the gas pressure of the coal seam is reduced to below 0.4 MPa,and the outburst danger is eliminated efectively.
基金supported by the Earmarked Fund for China Agriculture Research System(CARS-45-05)the Central Public-Interest Scientific Institution Basal Research Fund,Freshwater Fisheries Research Center,CAFS(2023JBFZ02,2023JBFM07).
文摘Ghrelin(ghrl)and its receptor gene ghsr(growth hormone secretagogue receptor)regulate numerous physio-logical functions,including growth hormone secretion and food intake.In the present study,we investigated the sequences and expression characteristics of these two genes in bighead carp(Hypophthalmichthys nobilis).The ghrl and ghsr genes encoded 106 and 346 amino acids,respectively,and were 1208 bp and 2239 bp in length.Early blastocysts exhibited the highest levels of ghrl and ghsr expression throughout early development(P<0.01).The gut exhibited the highest levels of ghrl expression,whereas significantly higher levels of ghsr(P<0.01)were detected in the brain.Significantly higher levels of ghrl and ghsr expression were detected in the intestine and muscle in summer compared to the levels in winter(P<0.05).Furthermore,the significantly higher levels of ghrl and ghsr expression were detected in the muscle of individuals with big size compared to the levels of individuals with small size(P<0.05).In situ hybridization analyses revealed that the intestine ghrl expression signals were more pronounced than intestinal ghsr expression signals,whereas the ghsr expression signals were more intense than those of ghrl in brain tissues.Finally,the co-expression patterns of related genes in the growth hormone synthesis,secretion,and action pathway(ko04935)and the cAMP signaling pathway(ko04024)indicated that ghrl and ghsr potentially regulate feeding and associated energy metabolism activities in bighead carp,in addition to influencinggrowth performance.
基金This publication was made possible through funding support from the National Science Foundation(DBI-1919574)the University of Nebraska at Omaha.
文摘Capture fisheries and aquaculture provide a significant amount of high-quality protein to human beings and thus play an essential role in ending global hunger and malnutrition.The availability of tens of hundreds of fish genomes and the advances of genomics have allowed addressing many challenging issues such as overfishing and germplasm degradation faced by fisheries and aquaculture.In this review,we describe the current status of genomics in fisheries and aquaculture,with an emphasis on 14 species of fish that are considerably important to global fisheries and aquaculture,in the context of genome sequencing and assembly,annotation,GC contents,and repeats.The majority of these genomes are assembled at the chromosome level and annotated with proteins and pathways,with functional relevance to fisheries and aquaculture,such as environmental adaptation and phenotypic variation.We summarize potential genomic applications in fisheries and aquaculture that are related to assessment and use of genetic resources,disease resistance,growth and development,sexual determination,and fisheries management.Although much progress has been achieved in genomic application to fisheries and aquaculture,the full potential remains to be explored and reaped.We discuss the challenges and perspectives of genomics in translational aquaculture and fisheries,which include genome assembly and annotation,genomic selection and breeding,genomics in fisheries management,and integrated artificial intelligence systems.In the coming decades,we anticipate the applications of genomic techniques such as genome editing and genomic selection,along with the use of emerging intelligence systems,in aquaculture and fisheries will contribute significantly to genetic improvements of farmed fish and sustainable exploitation of fishery resources,which consequently lead to eradicating global poverty by 2030,an ambitious goal set by the United Nations.
基金This publication was made possible through funding support from the National Science Foundation(DBI-1919574)and the University of Nebraska at Omaha.
文摘The CRISPR-Cas9 genome editing has many advantages over its counterparts and could ultimately assist in disease control and molecular breeding in aquaculture.Single-guide RNA(sgRNA)design is presumably the most crucial task in a typical CRISPR-Cas9 experiment;an understanding of algorithms behind sgRNA design programs is thus essential for improved efficacy and specificity.We focus this review on the bioinformatics aspects in genome editing experiments and describe commonly used computational approaches and tools of sgRNA design and outcome assessment.We show an example of sgRNA design with optimal parameter settings and appropriate interpretation of results and present a brief overview of CRISPR-Cas9 applications,such as genetic improvement and sustainability in aquaculture.We discuss challenging issues,particularly in the context of computational biology,in the use of computational tools in CRISPR-based genome editing.This review provides a synthesis of bioinformatics tools used for CRISPR-Cas9 sgRNA design and outcome assessment and offers a general view of CRISPR-based applications in farmed fish,which are expected to facilitate genome editing programs and hence improve aquaculture breeding,production,and sustainability.
基金the National Natural Science Foundation of China(Grant No.52104195)the Liaoning Revitalization Talents Program(No.XLYC2008021).
文摘Injecting external CO_(2) into soft and low-permeability coal seams can improve CH4 extacctinn efficiency, and also benefit in CO_(2) sequestration. However, the distribution law of damage zone around borehole in soft coal seam and its effect on the efficiency of CO_(2) injection promoted CH4 extraction are not clear. In this paper, a multi-physics coupling mathematical model considering damage effect is established for simulating the process of CO_(2) injection promoted CH4 extraction in soft and low-permeability coal seam. The distribution of damage zone and permeability around boreholes under different diameters and coal strengths are analyzed. The gas pressure and gas content in coal seam during CO_(2) injection promoted CH4 extraction when the model considered damage effect are compared with that of ignored. The results show that small borehole diameter corresponds to narrow damage zone around the borehole in coal seam. The damage zone expands with the increase of the borehole diameter. The damage zone increases exponentially with the borehole diameter, while decreases exponentially with the compressive strength of coal seam. The highest permeability in the damage zone has increased by nearly 300 times under the condition of simulated case. CH4 pressure around the extraction borehole reduces, and the reduction area expands with the increase of time. Compared with the result of considering the damage effect, the reduction area of ignoring it is smaller, and the reducing speed is slower. The integrated effect of CO_(2) injection and CH4 extraction leads to rapid decrease of CH4 content in coal seam near the boreholes. The CO_(2) pressure and content increase around the injection borehole, and the increasing area gradually extends to the whole coal seam. In soft coal seams, failure to consider the damage effect will underestimate the efficiency of CH4 extraction and CO_(2) sequestration, resulting conservative layout of boreholes.
