Liquid chromatography tandem mass chromatography(LC-MS/MS)is an important hyphenated technique for quantitative analysis of drugs in biological fluids.Because of high sensitivity and selectivity,LC-MS/MS has been used...Liquid chromatography tandem mass chromatography(LC-MS/MS)is an important hyphenated technique for quantitative analysis of drugs in biological fluids.Because of high sensitivity and selectivity,LC-MS/MS has been used for pharmacokinetic studies,metabolites identification in the plasma and urine.This manuscript gives comprehensive analytical review,focusing on chromatographic separation approaches(column packing materials,column length and mobile phase)as well as different acquisition modes(SIM,MRM)for quantitative analysis of glucocorticoids and stimulants.This review is not meant to be exhaustive but rather to provide a general overview for detection and confirmation of target drugs using LC-MS/MS and thus useful in the doping analysis,toxicological studies as well as in pharmaceutical analysis.展开更多
Repairing the endothelial barrier is essential for maintaining pulmonary fuid balance and regulating leukocyte infiltration during sepsis[1].Tissue kallikrein-related peptidases(KLKs)are secreted serine proteases invo...Repairing the endothelial barrier is essential for maintaining pulmonary fuid balance and regulating leukocyte infiltration during sepsis[1].Tissue kallikrein-related peptidases(KLKs)are secreted serine proteases involved in angiogenesis[2].However,their involvement in regulating endothelial regeneration remains largely unknown.展开更多
Background and Objective The natural history of type B aortic intramural hematoma(IMH)is highly heterogeneous.A computational fluid dynamics(CFD)model can be utilized to calculate a range of data pertinent to flow dyn...Background and Objective The natural history of type B aortic intramural hematoma(IMH)is highly heterogeneous.A computational fluid dynamics(CFD)model can be utilized to calculate a range of data pertinent to flow dynamics,including flow rates,blood velocity,pressure,and wall shear stress.This study presents a series of CFD simulations that model the dynamic progression from type B aortic IMH to false lumen formation.Methods A 66-year-old male patient presenting with chest and back pain underwent aortic computed tomography angiography(CTA),and a 3D patient-specific model was constructed.To evaluate the hemodynamic environment,the velocity,pressure,time-averaged wall shear stress(TAWSS),and oscillatory shear index(OSI)were calculated.Results A modest quantity of slow flow and recirculation flow was observed in the vicinity of the ulcer-like protrusion(ULP).During the formation of the false lumen,low-velocity blood flow entered the false lumen and resulted in vortex flow.ULPs were located in the region with higher TAWSS,and some high OSIs were found on the ULPs.Conclusion This preliminary study suggests a potential association between the TAWSS or OSI and progression from type B aortic IMH to aortic dissection.展开更多
This study examines the nonlinear behaviors of a clamped-clamped porous pipe made of a functionally graded material(FGM)that conveys fluids and is equipped with a retaining clip,focusing on primary resonance and subcr...This study examines the nonlinear behaviors of a clamped-clamped porous pipe made of a functionally graded material(FGM)that conveys fluids and is equipped with a retaining clip,focusing on primary resonance and subcritical dynamics.The nonlinear governing equations for the FGM pipe are derived by the extended Hamilton's principle,and subsequently discretized through the application of the Galerkin method.The direct method of multi-scales is then used to solve the derived equations.A thorough analysis of various parameters,including the clip stiffness,the power-law index,the porosity,and the clip location,is conducted to gain a comprehensive understanding of the system's nonlinear dynamics.Through the analysis of the first natural frequency,the study highlights the influence of the flow velocity and the clip stiffness,while the comparisons with metallic pipes emphasize the role of FGM composition.The examination of the forced response curves reveals saddle-node bifurcations and their dependence on parameters such as the detuning parameter and the power-law index,offering valuable insights into the system's nonlinear resonant behavior.Furthermore,the frequency-response curves illustrate the hardening nonlinearities influenced by factors such as the porosity and the clip stiffness,revealing nuanced effects on the system response and resonance characteristics.This comprehensive analysis enhances the understanding of nonlinear behaviors in FGM porous pipes with a retaining clip,providing key insights for practical engineering applications in system design and optimization.展开更多
针对纳米材料在钻井液中团聚的问题,通过分子设计,改进纳米材料的表面性能,以改性纳米二氧化硅为核,通过接枝柔性聚合物,合成了一种纳米封堵降滤失剂。通过引入强的吸附基团和疏水基团,聚合物分子的亲疏水、氢键等协同作用形成空间的网...针对纳米材料在钻井液中团聚的问题,通过分子设计,改进纳米材料的表面性能,以改性纳米二氧化硅为核,通过接枝柔性聚合物,合成了一种纳米封堵降滤失剂。通过引入强的吸附基团和疏水基团,聚合物分子的亲疏水、氢键等协同作用形成空间的网架结构,使合成的纳米封堵降滤失剂能够以纳米级尺度分散在钻井液中,其在钻井液中纳米级粒度的含量高达59.3%,其不仅具有优异的降滤失性能,同时具有柔性可变形性,还能够吸附在岩石表面,提高纳米材料对微裂缝和小孔隙的封堵能力。以合成的纳米降滤失剂为核心处理剂,并优选出配套的纳米润滑剂、纳米抑制剂,形成纳米钻井液体系。该体系的抗温达150℃,API滤失量在2.4 m L以下、高温高压滤失量在9.8 m L以下、润滑系数不大于0.04,渗透率恢复值不小于91%、目的层井段岩屑回收率≥90.5%。该体系在大港油田枣1510井的应用中表现出良好的润滑性和保护油气层效果。展开更多
文摘Liquid chromatography tandem mass chromatography(LC-MS/MS)is an important hyphenated technique for quantitative analysis of drugs in biological fluids.Because of high sensitivity and selectivity,LC-MS/MS has been used for pharmacokinetic studies,metabolites identification in the plasma and urine.This manuscript gives comprehensive analytical review,focusing on chromatographic separation approaches(column packing materials,column length and mobile phase)as well as different acquisition modes(SIM,MRM)for quantitative analysis of glucocorticoids and stimulants.This review is not meant to be exhaustive but rather to provide a general overview for detection and confirmation of target drugs using LC-MS/MS and thus useful in the doping analysis,toxicological studies as well as in pharmaceutical analysis.
基金supported by the National Natural Science Foundation of China(Grant Nos.:32171124,31871156,31971101,32271180,82272229,and 81471852)Hunan Provincial Natural Science Foundation of China(Grant No.:2021JJ31058).
文摘Repairing the endothelial barrier is essential for maintaining pulmonary fuid balance and regulating leukocyte infiltration during sepsis[1].Tissue kallikrein-related peptidases(KLKs)are secreted serine proteases involved in angiogenesis[2].However,their involvement in regulating endothelial regeneration remains largely unknown.
文摘Background and Objective The natural history of type B aortic intramural hematoma(IMH)is highly heterogeneous.A computational fluid dynamics(CFD)model can be utilized to calculate a range of data pertinent to flow dynamics,including flow rates,blood velocity,pressure,and wall shear stress.This study presents a series of CFD simulations that model the dynamic progression from type B aortic IMH to false lumen formation.Methods A 66-year-old male patient presenting with chest and back pain underwent aortic computed tomography angiography(CTA),and a 3D patient-specific model was constructed.To evaluate the hemodynamic environment,the velocity,pressure,time-averaged wall shear stress(TAWSS),and oscillatory shear index(OSI)were calculated.Results A modest quantity of slow flow and recirculation flow was observed in the vicinity of the ulcer-like protrusion(ULP).During the formation of the false lumen,low-velocity blood flow entered the false lumen and resulted in vortex flow.ULPs were located in the region with higher TAWSS,and some high OSIs were found on the ULPs.Conclusion This preliminary study suggests a potential association between the TAWSS or OSI and progression from type B aortic IMH to aortic dissection.
文摘This study examines the nonlinear behaviors of a clamped-clamped porous pipe made of a functionally graded material(FGM)that conveys fluids and is equipped with a retaining clip,focusing on primary resonance and subcritical dynamics.The nonlinear governing equations for the FGM pipe are derived by the extended Hamilton's principle,and subsequently discretized through the application of the Galerkin method.The direct method of multi-scales is then used to solve the derived equations.A thorough analysis of various parameters,including the clip stiffness,the power-law index,the porosity,and the clip location,is conducted to gain a comprehensive understanding of the system's nonlinear dynamics.Through the analysis of the first natural frequency,the study highlights the influence of the flow velocity and the clip stiffness,while the comparisons with metallic pipes emphasize the role of FGM composition.The examination of the forced response curves reveals saddle-node bifurcations and their dependence on parameters such as the detuning parameter and the power-law index,offering valuable insights into the system's nonlinear resonant behavior.Furthermore,the frequency-response curves illustrate the hardening nonlinearities influenced by factors such as the porosity and the clip stiffness,revealing nuanced effects on the system response and resonance characteristics.This comprehensive analysis enhances the understanding of nonlinear behaviors in FGM porous pipes with a retaining clip,providing key insights for practical engineering applications in system design and optimization.
文摘针对纳米材料在钻井液中团聚的问题,通过分子设计,改进纳米材料的表面性能,以改性纳米二氧化硅为核,通过接枝柔性聚合物,合成了一种纳米封堵降滤失剂。通过引入强的吸附基团和疏水基团,聚合物分子的亲疏水、氢键等协同作用形成空间的网架结构,使合成的纳米封堵降滤失剂能够以纳米级尺度分散在钻井液中,其在钻井液中纳米级粒度的含量高达59.3%,其不仅具有优异的降滤失性能,同时具有柔性可变形性,还能够吸附在岩石表面,提高纳米材料对微裂缝和小孔隙的封堵能力。以合成的纳米降滤失剂为核心处理剂,并优选出配套的纳米润滑剂、纳米抑制剂,形成纳米钻井液体系。该体系的抗温达150℃,API滤失量在2.4 m L以下、高温高压滤失量在9.8 m L以下、润滑系数不大于0.04,渗透率恢复值不小于91%、目的层井段岩屑回收率≥90.5%。该体系在大港油田枣1510井的应用中表现出良好的润滑性和保护油气层效果。
