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 bee...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
We carry out a theoretical investigation of the low-temperature phase diagram of muonium hydride in two dimensions,using numerical simulations.It is shown that the phase diagram of this substance is qualitatively diff...We carry out a theoretical investigation of the low-temperature phase diagram of muonium hydride in two dimensions,using numerical simulations.It is shown that the phase diagram of this substance is qualitatively different in two and three dimensions.Specifically,while in three dimensions it is essentially identical to that of parahydrogen,i.e.,only displaying a single(crystalline)phase.In two dimensions it is very similar to that of^(4)He,with an equilibrium liquid phase that turns superfluid at a temperature as high as~2.2 K,and crystallizes under applied pressure.This is a well-described case of a continuous-space condensed matter system whose ground state equilibrium phase is qualitatively altered by dimensional reduction.展开更多
Charge-based studies,in particular investigations of mass distribution,are still almost absent,although the efficiency of the organic Rankine cycle(ORC)has attracted a great deal of scholarly attention.This paper aims...Charge-based studies,in particular investigations of mass distribution,are still almost absent,although the efficiency of the organic Rankine cycle(ORC)has attracted a great deal of scholarly attention.This paper aims to provide a new perspective on the intrinsic relationship among the mass distribution,phase-zone distribution in the heat exchanger(HEX),charge of working fuid(WF),rotation speed of the pump(RSP),and system performance.A comprehensive ORC simulation model is presented by linking each component's sub-models,including the independent models for HEX,pump,and expander in an object-oriented fashion.The visualization study of mass distribution of the WF in the system is investigated under different working conditions.Furthermore,the volume and mass of the gas phase,two-phase and liquid phase of WF in the HEX and their variation rules are analyzed in-depth.Finally,the strategies of charge reduction considering HEX areas and pipe sizes are investigated.The results show that the model based on the interior-point method provides high levels of accuracy and robustness.The mass ratio of the WF is concentrated in the liquid receiver,especially in the regenerator,which is 32.9%and 21.9%of the total mass,respectively.Furthermore,2.4 kg(6.9%)WF in the system gradually migrates to the high-temperature side as the RSP increases while 6.1 kg(17.4%)WF migrates to the low-temperature side,especially to the condenser,as the charge in the system increases.Output power and efficiency both decrease gradually after the peak due to changes in RSP and charge.Last,reducing heat transfer areas of the condenser and regenerator is the most effective way to reduce WF charge.展开更多
Some of the most promising potential applications of nanotechnology to hydraulic fracturing of coal seam gas(CSG)are reviewed with a focus on Australian CSG wells.Three propitious applications were identifed:(1)Nanopa...Some of the most promising potential applications of nanotechnology to hydraulic fracturing of coal seam gas(CSG)are reviewed with a focus on Australian CSG wells.Three propitious applications were identifed:(1)Nanoparticle enhanced viscoelastic surfactants(VES)fracturing fuids to prevent fuid loss by up to 30%,made possible by the formation of pseudo-flter cakes and reducing the viscosity of the VES fuids.Besides,there is no requirement of clay control additives or biocides.(2)Nano-proppants to extend fracture networks and reduce proppant embedment by introducing them prior to the emplacement of larger proppants.Fly Ash nanoparticles can be particularly efective because of their high sphericity and mechanical strength.(3)Nanoparticle-coated proppants,to mitigate the migration of particle fnes by restricting them close to their source by adsorption,with MgO being the most efective.The use of nanotechnology in hydraulic fracturing applications is currently hindered due to a discordant regulatory environment compounded by the cost of the nanoparticles themselves,as well as,a lack of feld data to validate the technology under real downhole conditions.Although the necessary feld tests are unlikely to be conducted for as long as abundant natural gas is available,exploratory studies could pave the way for future applications.展开更多
Mud shale hydration and swelling are major challenges in the development of water-based drilling fuids(WBDFs).In this work,the inhibition performance and inhibition mechanism of polyethylene glycol(PEG)and potassium c...Mud shale hydration and swelling are major challenges in the development of water-based drilling fuids(WBDFs).In this work,the inhibition performance and inhibition mechanism of polyethylene glycol(PEG)and potassium chloride(KCl)were investigated by hot rolling recovery tests,linear swell tests,Fourier transform infrared spectroscopy,X-ray difraction,atomic absorption spectrophotometry and X-ray photoelectron spectroscopy.The experimental results show that the combination of PEG and KCl achieved higher recovery and lower linear swelling rate than those obtained by individual PEG or KCl.Compared to the d-spacing of Na-montmorillonite(Na-Mt)with PEG or KCl,the d-spacing of Na-Mt with PEG+KCl was lower,which indicates that KCl and PEG have synergistic inhibition efect.This synergistic efect can replace sodium ions and water molecules from the interlayer space of Na-Mt and decrease the d-spacing of Na-Mt.Based on the above experimental results and analysis,a method for optimizing PEG and KCl concentrations was proposed and further verifed by rheological and hot rolling recovery tests of WBDFs.Hence,the results of this work can provide valuable theoretical guidance for developing other synergistic inhibitors.展开更多
Background: Ovarian follicular fluids(FFs) contain several kinds of regulatory factors that maintain a suitable micro-environment for oocyte development. Extracellular vesicles(EVs) are among the factors that play ess...Background: Ovarian follicular fluids(FFs) contain several kinds of regulatory factors that maintain a suitable micro-environment for oocyte development. Extracellular vesicles(EVs) are among the factors that play essential roles in regulating follicle and oocyte development through their cargo molecules that include microRNAs(miRNAs). This study aimed to investigate small-EV(s-EV) miRNAs in porcine FFs and their potential association with oocyte quality.Methods: Individual aspirated oocytes were stained with lissamine green B stain(LB), a vital stain for oocyte quality, and each oocyte was classified as high-quality(unstained;HQ) or low-quality(stained;LQ). FFs corresponding to oocytes were pooled together into HQ and LQ groups. Small-EVs were isolated from FFs, characterized, and their miRNA cargo was identified using the Illumina Nova Seq sequencing platform. Additionally, s-EVs from the HQ and LQ groups were utilized to investigate their effect on oocyte development after co-incubation during in vitro maturation.Results: A total of 19 miRNAs(including miR-125b, miR-193a-5p, and miR-320) were significantly upregulated, while 23(including miR-9, miR-206, and miR-6516) were downregulated in the HQ compared to the LQ group. Apoptosis, p53 signaling, and cAMP signaling were among the top pathways targeted by the elevated miRNAs in the HQ group while oocyte meiosis, gap junction, and TGF-beta signaling were among the top pathways targeted by the elevated miRNAs in the LQ group. The supplementation of small-EVs during maturation does not affect the oocyte developmental rates. However, LQ s-EVs increase the proportion of oocytes with homogeneous mitochondrial distribution and decrease the proportion of heterogeneous distribution.Conclusion: Our findings indicated that FF-EVs contain different miRNA cargos associated with oocyte quality and could affect the mitochondrial distribution patterns during oocyte maturation.展开更多
Solid phases of visible fuorescence substance(VFS)of biological fuids(blood,urine,hemodia-lysate)which was proposed earlier as a morbidity and mortality marker by renal failure and diabetes were investigated in-depth ...Solid phases of visible fuorescence substance(VFS)of biological fuids(blood,urine,hemodia-lysate)which was proposed earlier as a morbidity and mortality marker by renal failure and diabetes were investigated in-depth by the methods of electron and confocal microscopy,optical spectroscopy and matrix assisted laser desorption-ionization(MALDI)mass spectroscopy.It is shown that dry VFS exists predominantly in the form of carbon-oxygen-nitrogen(N≈8.7 wt.%)nanoparticles(NPs)(5≤d≤100nm).For the first time the existence of the threshold energy E_(g)≈2.15eV for excitation of VFS was observed experimentally and confirmed by semi empirical calculations of the bathochromic shift.A good accordance with the earlier autonomous theo-retical calculations was achieved.Thus,the long wavelength limit(575 nm)of the spectral range where the VFS can be used as a fluorescent marker was reliably determined.A pilot MALDI comparative study of graphene oxide(GO)and urine VFS was carried out.Six kinds of nitrogen-free particles(412≤M≤456 Da)were observed in each substance and possible computer models of those have been composed.It is established that along with nitrogen-containing advanced glycation end products(AGEs)also nitrogen-fee carbon-oxygen-lhydrogen particles(probably toxic)with the composition and structure related to GO can exist in biofuids.Both types of particles should be taken into account in search for the reasons of high mortality among end stage renal disease patients.展开更多
AIM: To investigate whether administration of Ringer's solution(RL) could have an impact on the outcome of acute pancreatitis(AP).METHODS: We conducted a retrospective study on 103 patients [68 men and 35 women,me...AIM: To investigate whether administration of Ringer's solution(RL) could have an impact on the outcome of acute pancreatitis(AP).METHODS: We conducted a retrospective study on 103 patients [68 men and 35 women,mean age 51.2 years(range,19-92 years)] hospitalized between 2011 and 2012. All patients admitted to the Department of Gastroenterology of the Central Clinical Hospital of the Ministry of Interior(Poland) with a diagnosis of AP who had disease onset within 48 h of presentation were included in this study. Based on the presence of persistent organ failure(longer than 48 h) as a criterion for the diagnosis of severe AP(SAP) and the presence of local complications [diagnosis of moderately severe AP(MSAP)],patients were classified into 3 groups: mild AP(MAP),MSAP and SAP. Data were compared between the groups in terms of severity(using the revised Atlanta criteria) and outcome. Patients were stratified into 2 groups based on the type of fluid resuscitation: the 1-RL group who underwent standard fluid resuscitation with a RL 1000 m L solution or the 2-NS group who underwent standard fluid resuscitation with 1000 m L normal saline(NS). All patients from both groups received an additional 5% glucose solution(1000-1500 m L) and a multi-electrolyte solution(500-1000 m L).RESULTS: We observed 64(62.1%) patients with MAP,26(25.24%) patients with MSAP and 13(12.62%) patients with SAP. No significant difference in the distribution of AP severity between the two groups was found. In the 1-RL group,we identified 22(55.5%) MAP,10(25.5%) MSAP and 8(20.0%) SAP patients,compared with 42(66.7%) MAP,16(24.4%) MSAP and 5(7.9%) SAP cases in the 2-NS group(P = 0.187). The volumes of fluid administered during the initial 72-h period of hospitalization were similar among the patients from both the 1-RL and 2-NS groups(mean 3400 m L vs 3000 m L,respectively). No significant differences between the 1-RL and 2-NS groups were found in confirmed pancreatic necrosis [10 patients(25%) vs 12 patients(19%),respectively,P = 0.637]. There were no statistically significant differences between the 1-RL and 2-NS groups in the percentage of patients who required enteral nutrition(23 patients vs 17 patients,respectively,P = 0.534). Logistic regression analysis confirmed these findings(OR = 1.344,95%CI: 0.595-3.035,P = 0.477). There were no significant differences between the 1-RL and 2-NS groups in mortality and the duration of hospital stay(median of 9 d for both groups,P = 0.776).CONCLUSION: Our study failed to find any evidence that the administration of RL in the first days of AP leads to improved clinical outcomes.展开更多
Fibrous-type flters are used to capture dust particles in mining and other occupations where personnel are exposed for prolonged periods.Dust cleansing devices including fooded-bed dust scrubbers use these mesh-type m...Fibrous-type flters are used to capture dust particles in mining and other occupations where personnel are exposed for prolonged periods.Dust cleansing devices including fooded-bed dust scrubbers use these mesh-type multi-layered flters.These flters trap dust particles efciently on their surface and inside their mesh.However,their continued operation leads to dust build-up and clogging.This results in increased resistance of the flter and lowered airfow rate through the scrubber.This could potentially enhance the exposure of the miners.A non-clogging self-cleaning impingement screen type dust flter was designed by the authors for use in mining and industrial dust cleansing applications.The flter guides dirt-laden air through rapidly turning paths which forces it to shed heavier particles.The particles impact one of the impermeable solid metallic flter surfaces and are removed from the airstream.A full cone water spray installed upstream prevents any surface buildup of dust.This paper summaried the computer models generated to show the flter operations and laboratory experiments including optical particle counting to establish the cleaning efciency.展开更多
This paper deals with the asymptotic behavior of solutions of the stochastic g-Navier-Stokes equation driven by nonlinear noise.The existence and uniqueness of weak pullback mean random attractors for the equation in ...This paper deals with the asymptotic behavior of solutions of the stochastic g-Navier-Stokes equation driven by nonlinear noise.The existence and uniqueness of weak pullback mean random attractors for the equation in Bochner space is proven for when the diffusion terms are Lipschitz nonlinear functions.Furthermore,we also establish the existence of invariant measures for the equation.展开更多
Because the brain edema has a crucial impact on morbidity and mortality,it is important to develop a noninvasive method to monitor the process of the brain edema effectively.When the brain edema occurs,the optical pro...Because the brain edema has a crucial impact on morbidity and mortality,it is important to develop a noninvasive method to monitor the process of the brain edema effectively.When the brain edema occurs,the optical properties of the brain will change.The goal of this study is to access the feasibility and reliability of using noninvasive near-infrared spectroscopy(NIRS)monitoring method to measure the brain edema.Specifically,three models,including the water content changes in the cerebrospinal fuid(CSF),gray matter and white matter,were explored.Moreover,these models were numerically simulated by the Monte Carlo studies.Then,the phantom experiments were performed to investigate the light intensity which was measured at different detecting radius on the tissue surface.The results indicated that the light intensity correlated well with the conditions of the brain edema and the detecting radius.Briefly,at the detect ing radius of 3.0 cm and 4.0 cm,the light intensity has a high response to the change of tissue parameters and optical properties.Thus,it is possible to monitor the brain edema noninvasively by NIRS method and the light intensity is a reliable and simple parameter to assess the brain edema.展开更多
The sensitivity of moving particle semi-implicit(MPS)simulations to numerical parameters is investigated in this study.Although the verifcation and validation(V&V)are important to ensure accurate numerical results...The sensitivity of moving particle semi-implicit(MPS)simulations to numerical parameters is investigated in this study.Although the verifcation and validation(V&V)are important to ensure accurate numerical results,the MPS has poor perfor-mance in convergences with a time step size.Therefore,users of the MPS need to tune numerical parameters to ft results into benchmarks.However,such tuning parameters are not always valid for other simulations.We propose a practical numerical condition for the MPS simulation of a two-dimensional wedge slamming problem(i.e.,an MPS-slamming condition).The MPS-slamming condition is represented by an MPS-slamming number,which provides the optimum time step size once the MPS-slamming number,slamming velocity,deadrise angle of the wedge,and particle size are decided.The simulation study shows that the MPS results can be characterized by the proposed MPS-slamming condition,and the use of the same MPS-slamming number provides a similar fow.展开更多
The asymptotic analysis theory is a powerful mathematical tool employed in the study of complex systems.By exploring the behavior of mathematical models in the limit as certain parameters tend toward infinity or zero,...The asymptotic analysis theory is a powerful mathematical tool employed in the study of complex systems.By exploring the behavior of mathematical models in the limit as certain parameters tend toward infinity or zero,the asymptotic analysis facilitates the extraction of simplified limit-equations,revealing fundamental principles governing the original complex dynamics.We will highlight the versatility of asymptotic methods in handling different scenarios,ranging from fluid mechanics to biological systems and economic mechanisms,with a greater focus on the financial markets models.This short overview aims to convey the broad applicability of the asymptotic analysis theory in advancing our comprehension of complex systems,making it an indispensable tool for researchers and practitioners across different disciplines.In particular,such a theory could be applied to reshape intricate financial models(e.g.,stock market volatility models)into more manageable forms,which could be tackled with time-saving numerical implementations.展开更多
The purpose of this work is to investigate the boundedness of the pullback attractors for the micropolar fluid flows in two-dimensional unbounded domains.Exactly,the H1-boundedness and H2-boundedness of the pullback a...The purpose of this work is to investigate the boundedness of the pullback attractors for the micropolar fluid flows in two-dimensional unbounded domains.Exactly,the H1-boundedness and H2-boundedness of the pullback attractors are established when the external force F(t,x)has different regularity with respect to time variable,respectively.展开更多
This study investigates the accuracy and efficiency of a convolutional autoencoder in predicting flow solutions of diverse characteristics,including strong local nonlinea rity and unsteady wake vortices.Modifications ...This study investigates the accuracy and efficiency of a convolutional autoencoder in predicting flow solutions of diverse characteristics,including strong local nonlinea rity and unsteady wake vortices.Modifications to the standard U-net method were made suitable for non-Cartesian CFD mesh topology,enhancing solution accuracy.Additionally,conditions for predicting flows in unseen environments are integrated into a bottleneck layer between the encoder and decoder structures,guiding flow interpolation or extrapolation and parameter types.For direct comparison,this study uses a proper orthogonal decomposition(POD)-based ROM with linear reconstruction using dominant basis vectors from the flow solution space.Interpolation and extrapolation of generalized coordinates are performed using Gaussian process regression(GPR)and Long Short-Term Memory(LSTM)networks,respectively.The Conditional Unet(CUnet)'s accuracy is demonstrated through inviscid transonic airfoil flows,capturing shock waves effectively.Additionally,it can also be used for predicting the flow field of the three-dimensional shape of the Onera M6 wing.Vortex shedding flows around an Eppler airfoil at a 16-degree angle of attack in turbulent conditions were well-resolved,with root mean squared errors under 1%compared to full-order CFD results.Remarkably,the CUnet's computational efficiency is highlighted as the wall clock CPU time for these 2D flows was less than one second.Finally,the ROM's effectiveness is further validated through successful multi-point shape optimization,minimizing wave drag of RAE 2822 airfoils across subsonic to transonic conditions.This resulted in a maximum drag reduction of 37.38%at Mach 0.74 without performance degradation at off-design conditions.展开更多
In this paper,we first establish a new fractional magnetohydrodynamic(MHD)coupled flow and heat transfer model for a generalized second-grade fluid.This coupled model consists of a fractional momentum equation and a h...In this paper,we first establish a new fractional magnetohydrodynamic(MHD)coupled flow and heat transfer model for a generalized second-grade fluid.This coupled model consists of a fractional momentum equation and a heat conduction equation with a generalized form of Fourier law.The second-order fractional backward difference formula is applied to the temporal discretization and the Legendre spectral method is used for the spatial discretization.The fully discrete scheme is proved to be stable and convergent with an accuracy of O(τ^(2)+N-r),whereτis the time step-size and N is the polynomial degree.To reduce the memory requirements and computational cost,a fast method is developed,which is based on a globally uniform approximation of the trapezoidal rule for integrals on the real line.The strict convergence of the numerical scheme with this fast method is proved.We present the results of several numerical experiments to verify the effectiveness of the proposed method.Finally,we simulate the unsteady fractional MHD flow and heat transfer of the generalized second-grade fluid through a porous medium.The effects of the relevant parameters on the velocity and temperature are presented and analyzed in detail.展开更多
A new coupling numerical wave model, based on both the Boundary Element Method （BEM） and the Volume Of Fluid （VOF） method, is established by taking advantages of the both methods to solve the wave-structure intera...A new coupling numerical wave model, based on both the Boundary Element Method （BEM） and the Volume Of Fluid （VOF） method, is established by taking advantages of the both methods to solve the wave-structure interaction problems. In this model, the wave transformation in front of structures is calculated by the 0-1 type BEM, and the intense wave motions near the structures are calculated by the VOF method. In this paper, the characteristics of the BEM and the VOF method are discussed first, and then the coupling treatments are described in detail. In the end, the accuracy and the validity of the coupling model are examined by comparing the numerical results with experiment results and other numerical results available for the interactions between regular waves with a monolayer horizontal plate.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.
基金supported by the Natural Sciences and Engineering Research Council of Canada,and by the China Scholarship Council。
文摘We carry out a theoretical investigation of the low-temperature phase diagram of muonium hydride in two dimensions,using numerical simulations.It is shown that the phase diagram of this substance is qualitatively different in two and three dimensions.Specifically,while in three dimensions it is essentially identical to that of parahydrogen,i.e.,only displaying a single(crystalline)phase.In two dimensions it is very similar to that of^(4)He,with an equilibrium liquid phase that turns superfluid at a temperature as high as~2.2 K,and crystallizes under applied pressure.This is a well-described case of a continuous-space condensed matter system whose ground state equilibrium phase is qualitatively altered by dimensional reduction.
文摘Charge-based studies,in particular investigations of mass distribution,are still almost absent,although the efficiency of the organic Rankine cycle(ORC)has attracted a great deal of scholarly attention.This paper aims to provide a new perspective on the intrinsic relationship among the mass distribution,phase-zone distribution in the heat exchanger(HEX),charge of working fuid(WF),rotation speed of the pump(RSP),and system performance.A comprehensive ORC simulation model is presented by linking each component's sub-models,including the independent models for HEX,pump,and expander in an object-oriented fashion.The visualization study of mass distribution of the WF in the system is investigated under different working conditions.Furthermore,the volume and mass of the gas phase,two-phase and liquid phase of WF in the HEX and their variation rules are analyzed in-depth.Finally,the strategies of charge reduction considering HEX areas and pipe sizes are investigated.The results show that the model based on the interior-point method provides high levels of accuracy and robustness.The mass ratio of the WF is concentrated in the liquid receiver,especially in the regenerator,which is 32.9%and 21.9%of the total mass,respectively.Furthermore,2.4 kg(6.9%)WF in the system gradually migrates to the high-temperature side as the RSP increases while 6.1 kg(17.4%)WF migrates to the low-temperature side,especially to the condenser,as the charge in the system increases.Output power and efficiency both decrease gradually after the peak due to changes in RSP and charge.Last,reducing heat transfer areas of the condenser and regenerator is the most effective way to reduce WF charge.
基金supported,in part,by the Department of Chemical Engineering,University College Londonby the Futures Industries Institute of the University of South Australia.AS gratefully acknowledges fnancial support from the Horizon 2020 project‘Science 4 Clean Energy’+2 种基金supported by grant number 764810 from the European Commissionfrom the US Department of Energy,Ofce of Basic Energy Sciences,Division of Chemical Sciences,GeosciencesBiosciences,under grant number DE-SC0006878.MM gratefully acknowledges fnancial support from the Australian research council,FT200100301.
文摘Some of the most promising potential applications of nanotechnology to hydraulic fracturing of coal seam gas(CSG)are reviewed with a focus on Australian CSG wells.Three propitious applications were identifed:(1)Nanoparticle enhanced viscoelastic surfactants(VES)fracturing fuids to prevent fuid loss by up to 30%,made possible by the formation of pseudo-flter cakes and reducing the viscosity of the VES fuids.Besides,there is no requirement of clay control additives or biocides.(2)Nano-proppants to extend fracture networks and reduce proppant embedment by introducing them prior to the emplacement of larger proppants.Fly Ash nanoparticles can be particularly efective because of their high sphericity and mechanical strength.(3)Nanoparticle-coated proppants,to mitigate the migration of particle fnes by restricting them close to their source by adsorption,with MgO being the most efective.The use of nanotechnology in hydraulic fracturing applications is currently hindered due to a discordant regulatory environment compounded by the cost of the nanoparticles themselves,as well as,a lack of feld data to validate the technology under real downhole conditions.Although the necessary feld tests are unlikely to be conducted for as long as abundant natural gas is available,exploratory studies could pave the way for future applications.
基金This work was financially supported by the Natural Science Foundation of China(51974270)Innovation Union of China National Petroleum Corporation and Southwest Petroleum University(2020CX040102,2020CX040201)Open Fund(PLN201814)of the State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Southwest Petroleum University).
文摘Mud shale hydration and swelling are major challenges in the development of water-based drilling fuids(WBDFs).In this work,the inhibition performance and inhibition mechanism of polyethylene glycol(PEG)and potassium chloride(KCl)were investigated by hot rolling recovery tests,linear swell tests,Fourier transform infrared spectroscopy,X-ray difraction,atomic absorption spectrophotometry and X-ray photoelectron spectroscopy.The experimental results show that the combination of PEG and KCl achieved higher recovery and lower linear swelling rate than those obtained by individual PEG or KCl.Compared to the d-spacing of Na-montmorillonite(Na-Mt)with PEG or KCl,the d-spacing of Na-Mt with PEG+KCl was lower,which indicates that KCl and PEG have synergistic inhibition efect.This synergistic efect can replace sodium ions and water molecules from the interlayer space of Na-Mt and decrease the d-spacing of Na-Mt.Based on the above experimental results and analysis,a method for optimizing PEG and KCl concentrations was proposed and further verifed by rheological and hot rolling recovery tests of WBDFs.Hence,the results of this work can provide valuable theoretical guidance for developing other synergistic inhibitors.
基金supported by the Institute of Animal Physiology and Genetics“IAPG-Matoušek Award 2020”Grant number:DRMA-2020-0002the Ministry of Education,Youth and Sports of the Czech Republic,Operational Program Research,Development and Education,the project“EXCELLENCE in molecular aspects of the early development of vertebrates”Grant number:CZ.02.1.01/0.0/0.0/15_003/0000460.
文摘Background: Ovarian follicular fluids(FFs) contain several kinds of regulatory factors that maintain a suitable micro-environment for oocyte development. Extracellular vesicles(EVs) are among the factors that play essential roles in regulating follicle and oocyte development through their cargo molecules that include microRNAs(miRNAs). This study aimed to investigate small-EV(s-EV) miRNAs in porcine FFs and their potential association with oocyte quality.Methods: Individual aspirated oocytes were stained with lissamine green B stain(LB), a vital stain for oocyte quality, and each oocyte was classified as high-quality(unstained;HQ) or low-quality(stained;LQ). FFs corresponding to oocytes were pooled together into HQ and LQ groups. Small-EVs were isolated from FFs, characterized, and their miRNA cargo was identified using the Illumina Nova Seq sequencing platform. Additionally, s-EVs from the HQ and LQ groups were utilized to investigate their effect on oocyte development after co-incubation during in vitro maturation.Results: A total of 19 miRNAs(including miR-125b, miR-193a-5p, and miR-320) were significantly upregulated, while 23(including miR-9, miR-206, and miR-6516) were downregulated in the HQ compared to the LQ group. Apoptosis, p53 signaling, and cAMP signaling were among the top pathways targeted by the elevated miRNAs in the HQ group while oocyte meiosis, gap junction, and TGF-beta signaling were among the top pathways targeted by the elevated miRNAs in the LQ group. The supplementation of small-EVs during maturation does not affect the oocyte developmental rates. However, LQ s-EVs increase the proportion of oocytes with homogeneous mitochondrial distribution and decrease the proportion of heterogeneous distribution.Conclusion: Our findings indicated that FF-EVs contain different miRNA cargos associated with oocyte quality and could affect the mitochondrial distribution patterns during oocyte maturation.
基金support for this work by the Archimedes project 3.2.1101.12-0011supported in part by the institutional research funding IUT (IUT 2-26)of the Estonian Ministry of Education and Research.
文摘Solid phases of visible fuorescence substance(VFS)of biological fuids(blood,urine,hemodia-lysate)which was proposed earlier as a morbidity and mortality marker by renal failure and diabetes were investigated in-depth by the methods of electron and confocal microscopy,optical spectroscopy and matrix assisted laser desorption-ionization(MALDI)mass spectroscopy.It is shown that dry VFS exists predominantly in the form of carbon-oxygen-nitrogen(N≈8.7 wt.%)nanoparticles(NPs)(5≤d≤100nm).For the first time the existence of the threshold energy E_(g)≈2.15eV for excitation of VFS was observed experimentally and confirmed by semi empirical calculations of the bathochromic shift.A good accordance with the earlier autonomous theo-retical calculations was achieved.Thus,the long wavelength limit(575 nm)of the spectral range where the VFS can be used as a fluorescent marker was reliably determined.A pilot MALDI comparative study of graphene oxide(GO)and urine VFS was carried out.Six kinds of nitrogen-free particles(412≤M≤456 Da)were observed in each substance and possible computer models of those have been composed.It is established that along with nitrogen-containing advanced glycation end products(AGEs)also nitrogen-fee carbon-oxygen-lhydrogen particles(probably toxic)with the composition and structure related to GO can exist in biofuids.Both types of particles should be taken into account in search for the reasons of high mortality among end stage renal disease patients.
文摘AIM: To investigate whether administration of Ringer's solution(RL) could have an impact on the outcome of acute pancreatitis(AP).METHODS: We conducted a retrospective study on 103 patients [68 men and 35 women,mean age 51.2 years(range,19-92 years)] hospitalized between 2011 and 2012. All patients admitted to the Department of Gastroenterology of the Central Clinical Hospital of the Ministry of Interior(Poland) with a diagnosis of AP who had disease onset within 48 h of presentation were included in this study. Based on the presence of persistent organ failure(longer than 48 h) as a criterion for the diagnosis of severe AP(SAP) and the presence of local complications [diagnosis of moderately severe AP(MSAP)],patients were classified into 3 groups: mild AP(MAP),MSAP and SAP. Data were compared between the groups in terms of severity(using the revised Atlanta criteria) and outcome. Patients were stratified into 2 groups based on the type of fluid resuscitation: the 1-RL group who underwent standard fluid resuscitation with a RL 1000 m L solution or the 2-NS group who underwent standard fluid resuscitation with 1000 m L normal saline(NS). All patients from both groups received an additional 5% glucose solution(1000-1500 m L) and a multi-electrolyte solution(500-1000 m L).RESULTS: We observed 64(62.1%) patients with MAP,26(25.24%) patients with MSAP and 13(12.62%) patients with SAP. No significant difference in the distribution of AP severity between the two groups was found. In the 1-RL group,we identified 22(55.5%) MAP,10(25.5%) MSAP and 8(20.0%) SAP patients,compared with 42(66.7%) MAP,16(24.4%) MSAP and 5(7.9%) SAP cases in the 2-NS group(P = 0.187). The volumes of fluid administered during the initial 72-h period of hospitalization were similar among the patients from both the 1-RL and 2-NS groups(mean 3400 m L vs 3000 m L,respectively). No significant differences between the 1-RL and 2-NS groups were found in confirmed pancreatic necrosis [10 patients(25%) vs 12 patients(19%),respectively,P = 0.637]. There were no statistically significant differences between the 1-RL and 2-NS groups in the percentage of patients who required enteral nutrition(23 patients vs 17 patients,respectively,P = 0.534). Logistic regression analysis confirmed these findings(OR = 1.344,95%CI: 0.595-3.035,P = 0.477). There were no significant differences between the 1-RL and 2-NS groups in mortality and the duration of hospital stay(median of 9 d for both groups,P = 0.776).CONCLUSION: Our study failed to find any evidence that the administration of RL in the first days of AP leads to improved clinical outcomes.
基金Funding The authors acknowledge the National Institute for Occupational Safety and Health(NIOSH)for funding this research project.
文摘Fibrous-type flters are used to capture dust particles in mining and other occupations where personnel are exposed for prolonged periods.Dust cleansing devices including fooded-bed dust scrubbers use these mesh-type multi-layered flters.These flters trap dust particles efciently on their surface and inside their mesh.However,their continued operation leads to dust build-up and clogging.This results in increased resistance of the flter and lowered airfow rate through the scrubber.This could potentially enhance the exposure of the miners.A non-clogging self-cleaning impingement screen type dust flter was designed by the authors for use in mining and industrial dust cleansing applications.The flter guides dirt-laden air through rapidly turning paths which forces it to shed heavier particles.The particles impact one of the impermeable solid metallic flter surfaces and are removed from the airstream.A full cone water spray installed upstream prevents any surface buildup of dust.This paper summaried the computer models generated to show the flter operations and laboratory experiments including optical particle counting to establish the cleaning efciency.
基金supported by the National NaturalScience Foundation of China(11871138)the Sichuan Science and Technology Program(2023NSFSC0076)。
文摘This paper deals with the asymptotic behavior of solutions of the stochastic g-Navier-Stokes equation driven by nonlinear noise.The existence and uniqueness of weak pullback mean random attractors for the equation in Bochner space is proven for when the diffusion terms are Lipschitz nonlinear functions.Furthermore,we also establish the existence of invariant measures for the equation.
基金the Foundation of Graduate Innovation Center in NUAA(Grant No.kfjj20150310)National Natural Science Foundation of China(Grant Nos.61275199 and 61378092)the Fundamental Research Funds for the Central Universities(Grant Nos.NS2015032 and NS2015201).
文摘Because the brain edema has a crucial impact on morbidity and mortality,it is important to develop a noninvasive method to monitor the process of the brain edema effectively.When the brain edema occurs,the optical properties of the brain will change.The goal of this study is to access the feasibility and reliability of using noninvasive near-infrared spectroscopy(NIRS)monitoring method to measure the brain edema.Specifically,three models,including the water content changes in the cerebrospinal fuid(CSF),gray matter and white matter,were explored.Moreover,these models were numerically simulated by the Monte Carlo studies.Then,the phantom experiments were performed to investigate the light intensity which was measured at different detecting radius on the tissue surface.The results indicated that the light intensity correlated well with the conditions of the brain edema and the detecting radius.Briefly,at the detect ing radius of 3.0 cm and 4.0 cm,the light intensity has a high response to the change of tissue parameters and optical properties.Thus,it is possible to monitor the brain edema noninvasively by NIRS method and the light intensity is a reliable and simple parameter to assess the brain edema.
文摘The sensitivity of moving particle semi-implicit(MPS)simulations to numerical parameters is investigated in this study.Although the verifcation and validation(V&V)are important to ensure accurate numerical results,the MPS has poor perfor-mance in convergences with a time step size.Therefore,users of the MPS need to tune numerical parameters to ft results into benchmarks.However,such tuning parameters are not always valid for other simulations.We propose a practical numerical condition for the MPS simulation of a two-dimensional wedge slamming problem(i.e.,an MPS-slamming condition).The MPS-slamming condition is represented by an MPS-slamming number,which provides the optimum time step size once the MPS-slamming number,slamming velocity,deadrise angle of the wedge,and particle size are decided.The simulation study shows that the MPS results can be characterized by the proposed MPS-slamming condition,and the use of the same MPS-slamming number provides a similar fow.
文摘The asymptotic analysis theory is a powerful mathematical tool employed in the study of complex systems.By exploring the behavior of mathematical models in the limit as certain parameters tend toward infinity or zero,the asymptotic analysis facilitates the extraction of simplified limit-equations,revealing fundamental principles governing the original complex dynamics.We will highlight the versatility of asymptotic methods in handling different scenarios,ranging from fluid mechanics to biological systems and economic mechanisms,with a greater focus on the financial markets models.This short overview aims to convey the broad applicability of the asymptotic analysis theory in advancing our comprehension of complex systems,making it an indispensable tool for researchers and practitioners across different disciplines.In particular,such a theory could be applied to reshape intricate financial models(e.g.,stock market volatility models)into more manageable forms,which could be tackled with time-saving numerical implementations.
基金supported by the National Nature Science Foundation of China(No.12301294)the Natural Science Foundation of Hubei Province,China(No.2022CFB661)the Young and Middle-aged Talent Fund of Hubei Education Department,China(No.Q20201307).
文摘The purpose of this work is to investigate the boundedness of the pullback attractors for the micropolar fluid flows in two-dimensional unbounded domains.Exactly,the H1-boundedness and H2-boundedness of the pullback attractors are established when the external force F(t,x)has different regularity with respect to time variable,respectively.
基金supported by the National Research Council of Science&Technology(NST)grant by the Korea government(MSIT)(No.CRC21013)。
文摘This study investigates the accuracy and efficiency of a convolutional autoencoder in predicting flow solutions of diverse characteristics,including strong local nonlinea rity and unsteady wake vortices.Modifications to the standard U-net method were made suitable for non-Cartesian CFD mesh topology,enhancing solution accuracy.Additionally,conditions for predicting flows in unseen environments are integrated into a bottleneck layer between the encoder and decoder structures,guiding flow interpolation or extrapolation and parameter types.For direct comparison,this study uses a proper orthogonal decomposition(POD)-based ROM with linear reconstruction using dominant basis vectors from the flow solution space.Interpolation and extrapolation of generalized coordinates are performed using Gaussian process regression(GPR)and Long Short-Term Memory(LSTM)networks,respectively.The Conditional Unet(CUnet)'s accuracy is demonstrated through inviscid transonic airfoil flows,capturing shock waves effectively.Additionally,it can also be used for predicting the flow field of the three-dimensional shape of the Onera M6 wing.Vortex shedding flows around an Eppler airfoil at a 16-degree angle of attack in turbulent conditions were well-resolved,with root mean squared errors under 1%compared to full-order CFD results.Remarkably,the CUnet's computational efficiency is highlighted as the wall clock CPU time for these 2D flows was less than one second.Finally,the ROM's effectiveness is further validated through successful multi-point shape optimization,minimizing wave drag of RAE 2822 airfoils across subsonic to transonic conditions.This resulted in a maximum drag reduction of 37.38%at Mach 0.74 without performance degradation at off-design conditions.
基金supported by the Project of the National Key R&D Program(Grant No.2021YFA1000202)National Natural Science Foundation of China(Grant Nos.12120101001,12001326 and 12171283)+2 种基金Natural Science Foundation of Shandong Province(Grant Nos.ZR2021ZD03,ZR2020QA032 and ZR2019ZD42)China Postdoctoral Science Foundation(Grant Nos.BX20190191 and 2020M672038)the Startup Fund from Shandong University(Grant No.11140082063130)。
文摘In this paper,we first establish a new fractional magnetohydrodynamic(MHD)coupled flow and heat transfer model for a generalized second-grade fluid.This coupled model consists of a fractional momentum equation and a heat conduction equation with a generalized form of Fourier law.The second-order fractional backward difference formula is applied to the temporal discretization and the Legendre spectral method is used for the spatial discretization.The fully discrete scheme is proved to be stable and convergent with an accuracy of O(τ^(2)+N-r),whereτis the time step-size and N is the polynomial degree.To reduce the memory requirements and computational cost,a fast method is developed,which is based on a globally uniform approximation of the trapezoidal rule for integrals on the real line.The strict convergence of the numerical scheme with this fast method is proved.We present the results of several numerical experiments to verify the effectiveness of the proposed method.Finally,we simulate the unsteady fractional MHD flow and heat transfer of the generalized second-grade fluid through a porous medium.The effects of the relevant parameters on the velocity and temperature are presented and analyzed in detail.
基金the National Natural Science Foundation of China ( Grant No. 50921001)the Foundation of State Key Laboratory of Coastal and Offshore Engineering, Dalian University on Technology (Grant No. LP0804)
文摘A new coupling numerical wave model, based on both the Boundary Element Method （BEM） and the Volume Of Fluid （VOF） method, is established by taking advantages of the both methods to solve the wave-structure interaction problems. In this model, the wave transformation in front of structures is calculated by the 0-1 type BEM, and the intense wave motions near the structures are calculated by the VOF method. In this paper, the characteristics of the BEM and the VOF method are discussed first, and then the coupling treatments are described in detail. In the end, the accuracy and the validity of the coupling model are examined by comparing the numerical results with experiment results and other numerical results available for the interactions between regular waves with a monolayer horizontal plate.
