Liquid nitrogen has shown excellent performances as a good fracturing medium in the extraction of unconventional natural gas,and its application in coalbed methane extraction is currently a research hotspot.This study...Liquid nitrogen has shown excellent performances as a good fracturing medium in the extraction of unconventional natural gas,and its application in coalbed methane extraction is currently a research hotspot.This study focuses on the acoustic emission properties of coal specimens treated utilizing liquid nitrogen with varying initial temperatures in a three-point bending environment.Through examination of the load-displacement curves of the considered coal samples,their mechanical properties are also revealed for different initial temperatures and cycling frequencies.The findings demonstrate a gradual decline in the maximum load capacity of coal rock as the temperature rises.Similarly,when subjected to the same temperature,an escalation in the cycling frequency leads to a reduction in the peak load of coal rock.This suggests that both temperature and cycling frequency exert a notable impact on the fracturing efficacy of liquid nitrogen.Freeze-thaw cycling treatments and exposure to high-temperature conditions can activate preexisting damage in the coal rock,and,accordingly,influence its mechanical properties.In particular,throughout the progressive loading of coal rock samples,the failure mechanisms are predominantly characterized by the occurrence of tensile cracks,succeeded by the development,spread,and fracture of shear fissures.展开更多
Background Cold regions have long autumn and winter seasons and low ambient temperatures.When pigs are unable to adjust to the cold,oxidative damage and inflammation may develop.However,the differences between cold an...Background Cold regions have long autumn and winter seasons and low ambient temperatures.When pigs are unable to adjust to the cold,oxidative damage and inflammation may develop.However,the differences between cold and non-cold adaptation regarding glucose and lipid metabolism,gut microbiota and colonic mucosal immunological features in pigs are unknown.This study revealed the glucose and lipid metabolic responses and the dual role of gut microbiota in pigs during cold and non-cold adaptation.Moreover,the regulatory effects of dietary glucose supplements on glucose and lipid metabolism and the colonic mucosal barrier were evaluated in cold-exposed pigs.Results Cold and non-cold-adapted models were established by Min and Yorkshire pigs.Our results exhibited that cold exposure induced glucose overconsumption in non-cold-adapted pig models(Yorkshire pigs),decreasing plasma glucose concentrations.In this case,cold exposure enhanced the ATGL and CPT-1αexpression to promote liver lipolysis and fatty acid oxidation.Meanwhile,the two probiotics(Collinsella and Bifidobacterium)depletion and the enrichment of two pathogens(Sutterella and Escherichia-Shigella)in colonic microbiota are not conducive to colonic mucosal immunity.However,glucagon-mediated hepatic glycogenolysis in cold-adapted pig models(Min pigs)maintained the stability of glucose homeostasis during cold exposure.It contributed to the gut microbiota(including the enrichment of the Rikenellaceae RC9 gut group,[Eubacterium]coprostanoligenes group and WCHB1-41)that favored cold-adapted metabolism.Conclusions The results of both models indicate that the gut microbiota during cold adaptation contributes to the protection of the colonic mucosa.During non-cold adaptation,cold-induced glucose overconsumption promotes thermogenesis through lipolysis,but interferes with the gut microbiome and colonic mucosal immunity.Furthermore,glucagon-mediated hepatic glycogenolysis contributes to glucose homeostasis during cold exposure.展开更多
基金the National Natural Science Foundation(52004285)Fundamental Research Funds for the Central Universities from China University of Mining and Technology-Beijing(JCCXXNY06)the Open Fund of State Key Laboratory Cultivation Base for Gas Geology and Gas Control(Henan Polytechnic University)(WS2021A03).
文摘Liquid nitrogen has shown excellent performances as a good fracturing medium in the extraction of unconventional natural gas,and its application in coalbed methane extraction is currently a research hotspot.This study focuses on the acoustic emission properties of coal specimens treated utilizing liquid nitrogen with varying initial temperatures in a three-point bending environment.Through examination of the load-displacement curves of the considered coal samples,their mechanical properties are also revealed for different initial temperatures and cycling frequencies.The findings demonstrate a gradual decline in the maximum load capacity of coal rock as the temperature rises.Similarly,when subjected to the same temperature,an escalation in the cycling frequency leads to a reduction in the peak load of coal rock.This suggests that both temperature and cycling frequency exert a notable impact on the fracturing efficacy of liquid nitrogen.Freeze-thaw cycling treatments and exposure to high-temperature conditions can activate preexisting damage in the coal rock,and,accordingly,influence its mechanical properties.In particular,throughout the progressive loading of coal rock samples,the failure mechanisms are predominantly characterized by the occurrence of tensile cracks,succeeded by the development,spread,and fracture of shear fissures.
基金supported by the National Key R&D Program of China(2021YFD1300403)the Major Program of Heilongjiang Province of China(2021ZX12B08-02).
文摘Background Cold regions have long autumn and winter seasons and low ambient temperatures.When pigs are unable to adjust to the cold,oxidative damage and inflammation may develop.However,the differences between cold and non-cold adaptation regarding glucose and lipid metabolism,gut microbiota and colonic mucosal immunological features in pigs are unknown.This study revealed the glucose and lipid metabolic responses and the dual role of gut microbiota in pigs during cold and non-cold adaptation.Moreover,the regulatory effects of dietary glucose supplements on glucose and lipid metabolism and the colonic mucosal barrier were evaluated in cold-exposed pigs.Results Cold and non-cold-adapted models were established by Min and Yorkshire pigs.Our results exhibited that cold exposure induced glucose overconsumption in non-cold-adapted pig models(Yorkshire pigs),decreasing plasma glucose concentrations.In this case,cold exposure enhanced the ATGL and CPT-1αexpression to promote liver lipolysis and fatty acid oxidation.Meanwhile,the two probiotics(Collinsella and Bifidobacterium)depletion and the enrichment of two pathogens(Sutterella and Escherichia-Shigella)in colonic microbiota are not conducive to colonic mucosal immunity.However,glucagon-mediated hepatic glycogenolysis in cold-adapted pig models(Min pigs)maintained the stability of glucose homeostasis during cold exposure.It contributed to the gut microbiota(including the enrichment of the Rikenellaceae RC9 gut group,[Eubacterium]coprostanoligenes group and WCHB1-41)that favored cold-adapted metabolism.Conclusions The results of both models indicate that the gut microbiota during cold adaptation contributes to the protection of the colonic mucosa.During non-cold adaptation,cold-induced glucose overconsumption promotes thermogenesis through lipolysis,but interferes with the gut microbiome and colonic mucosal immunity.Furthermore,glucagon-mediated hepatic glycogenolysis contributes to glucose homeostasis during cold exposure.
