Achieving high energy density and fast charging of lithium-ion batteries can accelerate the promotion of electric vehicles.However,the increased mass loading causes poor charge transfer,impedes the electrochemical rea...Achieving high energy density and fast charging of lithium-ion batteries can accelerate the promotion of electric vehicles.However,the increased mass loading causes poor charge transfer,impedes the electrochemical reaction kinetics,and limits the battery charging rate.Herein,this work demonstrated a novel pattern integrated stamping process for creating channels in the electrode,which benefits ion transport and increases the rate performance of the electrode.Meanwhile,the pressure applied during the stamping process improved the contact between electrode and current collector and also enhanced the mechanical stability of the electrode.Compared to the conventional bar-coated electrode with the same thickness of 155μm(delivered a discharge capacity of 16 mAh g^(−1) at the rate of 3 C),the stamped low-tortuosity LiFePO_(4) electrode delivered 101 mAh g^(−1) capacity.Additionally,water was employed as a solvent in this study.Owing to its eco-friendliness,high scalability,and minimal waste generation,this novel stamping technique inspire a new method for the industrial-level efficient roll to roll fabrication of fast-charge electrodes.展开更多
Context: Diabetic patients are at high risk for microvascular complications of disease such as diabetic retinopathy (DR) and diabetic neuropathy. Imaging the retinal micro-vasculature offers a chance to measure quanti...Context: Diabetic patients are at high risk for microvascular complications of disease such as diabetic retinopathy (DR) and diabetic neuropathy. Imaging the retinal micro-vasculature offers a chance to measure quantitatively the microvascular changes in diabetic patients’ onset and progression. However, the relation between retinal biomarkers and diabetic risk factors is unclear in Chinese hospitalized type 2 diabetic patients. Aims: To examine the associations of retinal vascular tortuosity with risk factors of type 2 diabetes and diabetic retinopathy in Chinese hospitalized patients. Patients and Methods: Our cross-sectional study includes 504 participants with type 2 diabetes hospitalized in the department of endocrinology in Shengjing hospital, Shenyang, China. Patients’ socio-demographic, clinical and biological information was retrieved from their ID card, the interview, and the local hospital information system. Retinal photographs were taken by laser-scanning ophthalmoscopy of both eyes and checked if gradable for analysis. The weighted mean and standard deviation of tortuosity were calculated from the retinal photographs using a novel robust and fully automatic quantitative method. DR was assessed from the retinal photographs by the ophthalmologist according to the modified Airlie House classification into No DR and Any DR in our current study. Data were analyzed by SPSS Version 22 with Student’s t test, Mann-Whitney U test, Chi-square test, and linear regression. Results: For the total participants (504) in this study, the weighted mean and standard deviation (SD) of tortuosity was 12.05 × 10?3 (SD: 1.66 × 10?3) and 24.31 × 10?3 (SD: 3.69 × 10?3), respectively. 386 (76.6%) patients were diagnosed with DR who had older age, long duration of diabetes, higher brachial ankle pulse wave velocity (baPWV), higher systolic blood pressure (SBP), higher diastolic blood pressure (DBP), and higher retinal vascular tortuosity values. In univariable linear regression analyses, older age, longer duration, higher baPWV, higher urine microalbuminuria, higher urine albumin/creatinine ratio, diagnosed with high blood pressure, thrombosis or Any DR, were significantly associated with both higher tortuosity measures (all P values展开更多
Objective This study aimed to analyze the relationship between cardiorespiratory fitness(CRF)and the increasing severity of coronary artery tortuosity(CAT)in patients with non-stenosed coronaries.Methods A total of 39...Objective This study aimed to analyze the relationship between cardiorespiratory fitness(CRF)and the increasing severity of coronary artery tortuosity(CAT)in patients with non-stenosed coronaries.Methods A total of 396 patients who underwent coronary angiography and cardiopulmonary exercise testing(CPET)between August 2020 and July 2021 were included in this single-center retrospective study after excluding patients with significant coronary artery disease(≥50%stenosis).Patients were divided into two groups:no or mild coronary artery tortuosity(N/M-CAT)and moderate to severe coronary artery tortuosity(M/S-CAT)and laboratory electrocardiographic,echocardiographic,and CPET parameters were compared between two groups.Results M/S-CAT was found in 46.9%of the study participants,with 66.7%being women.M/S-CAT was significantly associated with advanced age(P=0.014)and females(P=0.001).Diastolic dysfunction parameters,E velocity(P=0.011),and E/A ratio(P=0.004)also revealed significant differences between the M/S-CAT group and N/M-CAT group.VO2@peak(1.22±0.39 vs.1.07±0.39,P<0.01)and VO2@AT(0.77±0.22 vs.0.71±0.21,P=0.017)were significantly lower in the M/S-CAT group than in the N/M-CAT group.Multivariate logistic regression analysis identified females(OR=0.448;95%CI,0.296–0.676;P=0.000)and E/A ratio(OR=0.307;95%CI,0.139–0.680;P=0.004)to be independent risk factors of M/S-CAT and showed no association of CPET parameters to M/S-CAT.Conclusion The results indicate that increasing severity of CAT is strongly associated with female gender and E/A ratio and is not directly correlated with decreasing CRF.Further research with a larger patient population and a longer follow-up time is required to fully comprehend the impact of CAT on CRF.展开更多
The aim of the research is to study the propagation of a hydraulic fracture with tortuosity due to contact areas between touching asperities on opposite crack walls. The tortuous fracture is replaced by a model symmet...The aim of the research is to study the propagation of a hydraulic fracture with tortuosity due to contact areas between touching asperities on opposite crack walls. The tortuous fracture is replaced by a model symmetric partially open fracture with a hyperbolic crack law and a modified Reynolds flow law. The normal stress at the crack walls is assumed to be proportional to the half-width of the model fracture. The Lie point symmetry of the nonlinear diffusion equation for the fracture half-width is derived and the general form of the group invariant solution is obtained. It was found that the fluid flux at the fracture entry cannot be prescribed arbitrarily, because it is determined by the group invariant solution and that the exponent n in the modified Reynolds flow power law must lie in the range 2 < <em>n</em> < 5. The boundary value problem is solved numerically using a backward shooting method from the fracture tip, offset by 0 < <em>δ</em> <span style="white-space:nowrap;">≪</span> 1 to avoid singularities, to the fracture entry. The numerical results showed that the tortuosity and the pressure due to the contact regions both have the effect of increasing the fracture length. The spatial gradient of the half-width was found to be singular at the fracture tip for 3 < <em>n</em> < 5, to be finite for the Reynolds flow law <em>n</em> = 3 and to be zero for 2 < <em>n</em> < 3. The thin fluid film approximation breaks down at the fracture tip for 3 < <em>n</em> < 5 while it remains valid for increasingly tortuous fractures with 2 < <em>n</em> < 3. The effect of the touching asperities is to decrease the width averaged fluid velocity. An approximate analytical solution for the half-width, which was found to agree well with the numerical solution, is derived by making the approximation that the width averaged fluid velocity increases linearly with distance along the fracture.展开更多
The sluggish K^(+)kinetics and structural instability of the generally-used graphite and other carbon-based materials hinder the development of potassium-ion batteries(PIBs)for high-rate capability and long-term cycli...The sluggish K^(+)kinetics and structural instability of the generally-used graphite and other carbon-based materials hinder the development of potassium-ion batteries(PIBs)for high-rate capability and long-term cycling.Herein,inspired by the unique flake structure and chemical composition of cytomembrane and cytoderm,we design high-tortuosity holey graphene as a highly efficient anode for PIBs.The flake cytomembrane and cytoderm shrink into wrinkled morphology during drying and sintering and then convert into high-tortuosity graphene after oxidative exfoliating and thermal reducing process.Mean-while,the proteins,sugars,and glycolipids embedded in cytomembrane and cytoderm can in-situ form nanoholes with highly abundant oxygenic groups and heteroatoms around,which can be easily removed and finally the high-tortuosity holey graphene is obtained after a thermal reducing process.The stress distribution after K^(+)intercalation confirms the optimized release of strain caused by the volume change through the finite element method.Benefiting from the unique nanoholes shortening the ion-diffusion length,the synergy of wrinkled and holey structure stabilizing volume fluctuation,and the enhanced electronic conductivity and specific surface area,the high-tortuosity holey graphene demonstrates high reversible capacities of 410 mAh g^(-1)at 25 mA g^(-1)after 150 cycles and retains 91.5%at 2 A g^(-1)after 2500 cycles.展开更多
Abundant FeS2 with high theoretical capacity is one of the promising anode candidates in sodium-ion batteries(SlBs),however,the uneven sodium deposition due to the poor interface compatibility and sluggish reaction ki...Abundant FeS2 with high theoretical capacity is one of the promising anode candidates in sodium-ion batteries(SlBs),however,the uneven sodium deposition due to the poor interface compatibility and sluggish reaction kinetics because of the high activation barrier still plague its practical application.Herein,we synthesized the ordered porous carbon matrix wrapped FeS2 nanoparticles(FeS_2@OCN)with high sodium wettability and low pore tortuosity to economically enhance the interface compatibility as well as to lower the energy barrier in SIBs.The synergistic effects of low tortuosity pores and strong sodium wettability homogenize the Na+flux distribution,bring the electron dislocation via the enrichment of edgenitrogen(Pyridinic N and Pyrrolic N),thus achieving the dendrite-free sodium deposition and dramatically enhanced reaction kinetics.Benefiting from exceptional structural/compositional/electronic merits,the resultant anode is endowed with exceptional structure stability,achieving long-term cycling stability of 451.9 mAh·g^(-1)after 1000cycles at 1 A·g^(-1)with specific capacity retention of 92.9%.Attenuated electrode tortuosity and high sodium wettability can corporately improve the interface compatibility and attenuate the activation barrier of the FeS_2 host and beyond.展开更多
The path tortuosity t is an indicator of rill morphology accounting for the deviation of the thalweg from a straight alignment.The effect of t on flow resistance has been little investigated for rills.This paper repor...The path tortuosity t is an indicator of rill morphology accounting for the deviation of the thalweg from a straight alignment.The effect of t on flow resistance has been little investigated for rills.This paper reports the results of a plot investigation aimed to establish the suitable accuracy of the rill thalweg measurement to determine the tortuosity parameter and to test the reliability of a theoretical flow resistance law.Four rills were incised in clay soil(CS)and clay-loam soil(LS)and shaped by a clear flow discharge.The three-dimensional Digital Terrain Models were created by the Structure from Motion technique.For rills on LS,an approximate thalweg was tracked by photo-interpretation,and a specific calculation routine was applied to identify the cross sections with a constant spacing d.The actual rill thalweg was obtained as the line joining the lowest points of these cross-sections.Among the different tested d values,d=0.075 m was chosen to determine t.For both CS and LS,the Darcy-Weisbach friction factorffeatured a non-monotonic relation with t,which was explained as the result of three additive components due to bed roughness,sediment transport,and localized energy losses due to curves.The effect of the former two components onff contrasts that of the third,resulting in a linearly decreasing f-t relationship and constant flow velocity for the three lowest tortuosity values,and an increased friction factor and reduced flow velocity for the highest tortuosity value.The flow resistance law was positively tested,and the predicted friction factor was dependent on t.展开更多
Based on the tortuous capillary network model,the relationship between anisotropic permeability and rock normal strain,namely the anisotropic dynamic permeability model(ADPM),was derived and established.The model was ...Based on the tortuous capillary network model,the relationship between anisotropic permeability and rock normal strain,namely the anisotropic dynamic permeability model(ADPM),was derived and established.The model was verified using pore-scale flow simulation.The uniaxial strain process was calculated and the main factors affecting permeability changes in different directions in the deformation process were analyzed.In the process of uniaxial strain during the exploitation of layered oil and gas reservoirs,the effect of effective surface porosity on the permeability in all directions is consistent.With the decrease of effective surface porosity,the sensitivity of permeability to strain increases.The sensitivity of the permeability perpendicular to the direction of compression to the strain decreases with the increase of the tortuosity,while the sensitivity of the permeability in the direction of compression to the strain increases with the increase of the tortuosity.For layered reservoirs with the same initial tortuosity in all directions,the tortuosity plays a decisive role in the relative relationship between the variations of permeability in all directions during pressure drop.When the tortuosity is less than 1.6,the decrease rate of horizontal permeability is higher than that of vertical permeability,while the opposite is true when the tortuosity is greater than 1.6.This phenomenon cannot be represented by traditional dynamic permeability model.After the verification by experimental data of pore-scale simulation,the new model has high fitting accuracy and can effectively characterize the effects of deformation in different directions on the permeability in all directions.展开更多
In this paper,we simulate the pressure driven fluid flow at the pore scale level through 2-D porous media,which is composed of different curved channels via the lattice Boltzmann method.With this direct simulation,the...In this paper,we simulate the pressure driven fluid flow at the pore scale level through 2-D porous media,which is composed of different curved channels via the lattice Boltzmann method.With this direct simulation,the relation between the tortuosity and the permeability is examined.The numerical results are in good agreement with the existing theory.展开更多
This study explored the complex effect of graphite tortuosity on the electrochemical performance of Ni-rich NCA90 Li-ion batteries(LIBs).Different levels of graphite anode tortuosity were analyzed,revealing that low-t...This study explored the complex effect of graphite tortuosity on the electrochemical performance of Ni-rich NCA90 Li-ion batteries(LIBs).Different levels of graphite anode tortuosity were analyzed,revealing that low-tortuosity electrodes had better graphite utilization.The in-plane tortuosities of the graphite anode electrodes examined were 1.70,1.94,2.05,and 2.18,while their corresponding through-plane tortuosities were 4.74,6.94,8.19,and 9.80.In-operando X-ray diffraction and differential electrochemical mass spectrometry were employed to investigate the charge storage mechanism and gas evolution.The study revealed that while graphite electrode tortuosity impacted the amount of Li present in the lithiated graphite phase due to diffusion constraints,it did not affect gas generation.The Li-ion utilization in low-tortuosity electrodes was higher than that in high-tortuosity electrodes because of solid-diffusion limitations.Additionally,the galvanostatic intermittent titration technique(GITT) was employed to investigate a lithium-ion diffusion coefficient.Our results indicate that the lithium-ion diffusion coefficient exhibits a significant difference only during LiC_(6) phase transition.We also observed that the use of a lower tortuosity electrode leads to improved lithium-ion insertion.Consequently,graphite utilization is influenced by the porous electrode design.Safety tests adhering to UN38.3 guidelines verified battery safety.The study demonstrated the practical application of optimized NCA90 LIB cells with diverse graphite electrode tortuosities in a high-performance Lamborghini GoKart,paving the way for further advancements in Ni-rich LIB technology.展开更多
Understanding the integrated transport behavior of oil in shale nanopores is critical to efficient shale oil development. In this paper, based on the time-dependent Poiseuille flow momentum equation, we present a nove...Understanding the integrated transport behavior of oil in shale nanopores is critical to efficient shale oil development. In this paper, based on the time-dependent Poiseuille flow momentum equation, we present a novel transient model to describe oil transport in unsteady and steady states. The model incorporates the effect of the critical shift density, apparent viscosity, slip length, and alkane property, as well as pore tortuosity and surface roughness. We evaluated our model through a comparison with other models, experiments, and molecular dynamics simulations. The results show that the development rates of the volume flows of C_(6)–C_(12) alkane confined in inorganic nanopores and C_(12) alkane confined in organic nanopores were faster than that of the corresponding bulk alkane. In addition, the critical drift density positively promoted the volume flow development rate in the unsteady state and negatively inhibited the mass flow rate in the steady state. This effect was clearest in pores with a smaller radius and lower-energy wall and in alkane with shorter chain lengths. Furthermore, both the nanoconfinement effect and pore structure determined whether the volume flow enhancement rate was greater than or less than 1. The rate increased or decreased with time and was controlled mainly by the nanoconfinement effect. Moreover, as the wall energy increased, the flow inhibition effect increased;as the carbon number of alkane increased, the flow promotion effect increased. The results indicate that the proposed model can accurately describe oil transport in shale nanopores.展开更多
BACKGROUND A carotid-cavernous fistula(CCF)is an abnormal connection between the internal carotid artery(ICA)and the cavernous sinus.Although direct CCFs typically result from trauma or as an iatrogenic complication o...BACKGROUND A carotid-cavernous fistula(CCF)is an abnormal connection between the internal carotid artery(ICA)and the cavernous sinus.Although direct CCFs typically result from trauma or as an iatrogenic complication of neuroendovascular procedures,they can occur as surgery-related complications after mechanical thrombectomy(MT).With the widespread use of MT in patients with acute ischemic stroke complicated with large vessel occlusion,it is important to document CCF following MT and how to avoid them.In this study,we present a case of a patient who developed a CCF following MT and describe in detail the characteristics of ICA tortuosity in this case.CASE SUMMARY A 60-year-old woman experienced weakness in the left upper and lower limbs as well as difficulty speaking for 4 h.The neurological examination revealed left central facial paralysis and left hemiplegia,with a National Institutes of Health Stroke Scale score of 9.Head magnetic resonance imaging revealed an acute cerebral infarction in the right basal ganglia and radial crown.Magnetic resonance angiography demonstrated an occlusion of the right ICA and middle cerebral artery.Digital subtraction angiography demonstrated distal occlusion of the cervical segment of the right ICA.We performed suction combined with stent thrombectomy.Then,postoperative angiography was performed,which showed a right CCF.One month later,CCF embolization was performed,and the patient’s clinical symptoms have significantly improved 5 mo after the operation.CONCLUSION Although a CCF is a rare complication after MT,it should be considered.Understanding the tortuosity of the internal carotid-cavernous sinus may help predict the complexity of MT and avoid this complication.展开更多
Pore network,pore connectivity,and the resulting effective adsorbate pore diffusivity within an adsorbent are critical physical considerations in mass transport modeling of aqueous adsorption.Tied to these three adsor...Pore network,pore connectivity,and the resulting effective adsorbate pore diffusivity within an adsorbent are critical physical considerations in mass transport modeling of aqueous adsorption.Tied to these three adsorbent features are the adsorbent tortuosity and tortuosity factor concepts.These concepts encompass the collective hindrance to intra-adsorbent adsorbate transport arising because of a disorderly adsorbent porous topology.It is crucial for materials scientists,chemists,chemical engineers,and water treatment specialists to understand the complex and variable connections among adsorbate chemistry,adsorbent chemistry,adsorbent porosity,pore shape,size,and tortuosity,pore wall effect,adsorbate-adsorbent interactions,and adsorbate-adsorbate interactions in competitively contaminated aqueous environments.Adsorbent tortuosity has been sporadically studied in aqueous adsorption models.Despite the small population of these studies,insightful observations and inferences have been reported.However,as it appears,no review has been published to compile,compare,and contrast these aspects.Hence,this review concisely brings up those observations and interpretations around adsorbent tortuosity for aqueous adsorption systems.The notion of an adsorbent's tortuosity being single-valued is argued to be imprecise.Finally,perspectives are aired on possible research and development directions for elucidating the dynamic attributes of adsorbent tortuosity and applying them in real-scale adsorption-oriented water purification.The data acquired by filling in these research gaps can enable the design of adsorbents more adapted for real-scale water purification.展开更多
Neurotrophins play a major role in the regulation of neuronal growth such as neurite sprouting or regeneration in response to nerve injuries. The role of nerve growth factor, neurotrophin-3, and brain-derived neurotro...Neurotrophins play a major role in the regulation of neuronal growth such as neurite sprouting or regeneration in response to nerve injuries. The role of nerve growth factor, neurotrophin-3, and brain-derived neurotrophic factor in maintaining the survival of peripheral neurons remains poorly understood. In regenerative medicine, different modalities have been investigated for the delivery of growth factors to the injured neurons, in search of a suitable system for clinical applications. This study was to investigate the influence of nerve growth factor, neurotrophin-3 and brain-derived neurotrophic factor on the growth of neurites using two in vitro models of dorsal root ganglia explants and dorsal root ganglia-derived primary cell dissociated cultures. Quantitative data showed that the total neurite length and tortuosity were differently influenced by trophic factors. Nerve growth factor and, indirectly, brain-derived neurotrophic factor stimulate the tortuous growth of sensory fibers and the formation of cell clusters. Neurotrophin-3, however, enhances neurite growth in terms of length and linearity allowing for a more organized and directed axonal elongation towards a peripheral target compared to the other growth factors. These findings could be of considerable importance for any clinical application of neurotrophic factors in peripheral nerve regeneration. Ethical approval was obtained from the Regione Piemonte Animal Ethics Committee ASLTO1(file # 864/2016-PR) on September 14, 2016.展开更多
The use of mechanical drilling in accessing energy resources stored in deep and hard rock formations is becoming increasingly challenging.Thus,laser irradiation has emerged as a novel drilling method with considerable...The use of mechanical drilling in accessing energy resources stored in deep and hard rock formations is becoming increasingly challenging.Thus,laser irradiation has emerged as a novel drilling method with considerable in this context.This study examines the variation of rock fracture length,fracture tortuosity,hole size,and rock breaking efficiency for a different number of holes and laser power,based on the constant total energy of laser irradiation.As indicated by the results,increasing the laser power increases the laser intensity,which helps increase the hole diameter and depth.Moreover,for the same laser power,increasing the number of irradiated holes reduces the laser energy absorbed by each hole,which is not conducive to increasing the hole depth.As the number of holes increases,the mass loss of the rock also increases,while both specific energy(SE)and modified specific energy(MSE)decrease.When the number of holes remains the same,the mass of the shale removed by low power is less than that removed by high power,while SE and MSE have an inverse relation with power.Therefore,high laser power and multiple-hole irradiation are more conducive to rock breaking.Besides,the fracture length and fracture tortuosity of the rock irradiated by the low laser power will increase first and then decrease with the increase in the number of holes,and reach the peak value when the irradiation takes place through three holes.When a high-power laser irradiates the rock,the fracture length and tortuosity will increase with the increase in the number of irradiation holes.This is because a rock irradiated by low power dissipates more energy,with the result that the energy absorbed by the sample with four irradiation holes is not enough to break the rock quickly.This study is expected to provide some guidance to break rock for drilling deep reservoirs and hard rock formations using laser irradiation.展开更多
Several theories point to the influence of the geometry of femoral arterial bifurcation in the formation and evolution of atherosclerosis plaques at the level of common, superficial and deep femoral arteries. The obje...Several theories point to the influence of the geometry of femoral arterial bifurcation in the formation and evolution of atherosclerosis plaques at the level of common, superficial and deep femoral arteries. The objective of this study is to correlate the degrees of calcifications of the femoral tripod with different morphological parameters, namely conicity, tortuosity, proximal and distal diameters of the arteries and angles between the common femoral artery (CFA) and the superficial femoral artery (SFA) and the profound femoral artery (PFA) and the superficial femoral artery. The results showed that only the tortuosity of the common femoral artery influences the formation of atherosclerosis plaque. These results allow us to predict the degree of calcification of the femoral tripod based on the tortuosity of the common femoral artery.展开更多
A fractal pore diffusion model of fiuidS in porous media which is in good agreement with the experimental data of the coke-CO2 reaction, has been derived by using the Mandelbrot’s fractal length-area relation. Based ...A fractal pore diffusion model of fiuidS in porous media which is in good agreement with the experimental data of the coke-CO2 reaction, has been derived by using the Mandelbrot’s fractal length-area relation. Based on the model, a new formula and its interpretation about the tortuosity of pore structures of a porous medium have been suggested, from which the fructal pore dthesion resistance has been defined. The resistance ascends obviously with the fmctal pore dimension and the conversion rutio increasing, especially in the middle-latter period of fiuid-solid reactions.展开更多
Internal diffusion of molecules in porous materials plays an important role in many chemical processes.However, the pore diffusion capacity of porous materials cannot be measured by conventional catalyst characterizat...Internal diffusion of molecules in porous materials plays an important role in many chemical processes.However, the pore diffusion capacity of porous materials cannot be measured by conventional catalyst characterization methods. In the present paper, a pore diffusion factor, the ratio of the diffusionconstriction factor to the pore tortuosity of the porous materials, was proposed to measure the diffusion ability of pores inside solid materials, and a method was proposed for measuring the diffusion factor using a well-defined and uniform pore size material as a reference. The diffusion factor was calculated based on the effective diffusion coefficients and the diffusion-constriction factor and pore tortuosity of the reference porous materials. The pore diffusion factor measurement can be performed at room temperature and atmospheric pressure. The pore diffusion factor of conventional porous materials was found to be much smaller than 1, indicating that there is a lot of room for improving the diffusion ability of the conventional catalysts and adsorbents, and could be significantly increased through adding small number of fibers into the conventional porous materials as template.展开更多
We present a case of a patient who presented with chest pain,and on diagnostic coronary angiography appeared to have a grossly angulated yet significant coronary stenosis.This was proven to be an artefactual appearanc...We present a case of a patient who presented with chest pain,and on diagnostic coronary angiography appeared to have a grossly angulated yet significant coronary stenosis.This was proven to be an artefactual appearance on further assessment with intravascular ultrasound imaging.We describe the causes and associations of coronary tortuosity with other arteriopathy,and highlight challenges in the interpretation of tortuous vessels to accurately assess luminal narrowing and suitability for coronary intervention.We describe a case of artefactual coronary stenosis,and its thorough assessment with intravascular ultrasound.A literature review describes the pathogenesis of coronary tortuosity,and links with other cardiovascular disease.Readers will gain an understanding of the challenge in determining the severity of luminal stenosis based on coronary angiography alone in tortuous coronary anatomy,the use of intravascular ultrasound in this setting,and the allied vasculopathies of interest.展开更多
A chromatographic method and a dynamic Wicke-Kallenbach method (DMWK) were used to determine the diffusion characteristics of two industrial copper containing catalysts. The first catalyst was used in nitrobenzene hyd...A chromatographic method and a dynamic Wicke-Kallenbach method (DMWK) were used to determine the diffusion characteristics of two industrial copper containing catalysts. The first catalyst was used in nitrobenzene hydrogenation to aniline and the second was used in a low temperature water-gas shift reaction. Experimental results show that application of these two methods leads to similar results. Experimental data obtained allow for monitoring changes in the texture of the catalyst grains and intraparticle diffusivity of gaseous reagents at different states of the catalyst activity and use, which can be used as criteria for designing optimal industrial catalyst pellets.展开更多
文摘Achieving high energy density and fast charging of lithium-ion batteries can accelerate the promotion of electric vehicles.However,the increased mass loading causes poor charge transfer,impedes the electrochemical reaction kinetics,and limits the battery charging rate.Herein,this work demonstrated a novel pattern integrated stamping process for creating channels in the electrode,which benefits ion transport and increases the rate performance of the electrode.Meanwhile,the pressure applied during the stamping process improved the contact between electrode and current collector and also enhanced the mechanical stability of the electrode.Compared to the conventional bar-coated electrode with the same thickness of 155μm(delivered a discharge capacity of 16 mAh g^(−1) at the rate of 3 C),the stamped low-tortuosity LiFePO_(4) electrode delivered 101 mAh g^(−1) capacity.Additionally,water was employed as a solvent in this study.Owing to its eco-friendliness,high scalability,and minimal waste generation,this novel stamping technique inspire a new method for the industrial-level efficient roll to roll fabrication of fast-charge electrodes.
文摘Context: Diabetic patients are at high risk for microvascular complications of disease such as diabetic retinopathy (DR) and diabetic neuropathy. Imaging the retinal micro-vasculature offers a chance to measure quantitatively the microvascular changes in diabetic patients’ onset and progression. However, the relation between retinal biomarkers and diabetic risk factors is unclear in Chinese hospitalized type 2 diabetic patients. Aims: To examine the associations of retinal vascular tortuosity with risk factors of type 2 diabetes and diabetic retinopathy in Chinese hospitalized patients. Patients and Methods: Our cross-sectional study includes 504 participants with type 2 diabetes hospitalized in the department of endocrinology in Shengjing hospital, Shenyang, China. Patients’ socio-demographic, clinical and biological information was retrieved from their ID card, the interview, and the local hospital information system. Retinal photographs were taken by laser-scanning ophthalmoscopy of both eyes and checked if gradable for analysis. The weighted mean and standard deviation of tortuosity were calculated from the retinal photographs using a novel robust and fully automatic quantitative method. DR was assessed from the retinal photographs by the ophthalmologist according to the modified Airlie House classification into No DR and Any DR in our current study. Data were analyzed by SPSS Version 22 with Student’s t test, Mann-Whitney U test, Chi-square test, and linear regression. Results: For the total participants (504) in this study, the weighted mean and standard deviation (SD) of tortuosity was 12.05 × 10?3 (SD: 1.66 × 10?3) and 24.31 × 10?3 (SD: 3.69 × 10?3), respectively. 386 (76.6%) patients were diagnosed with DR who had older age, long duration of diabetes, higher brachial ankle pulse wave velocity (baPWV), higher systolic blood pressure (SBP), higher diastolic blood pressure (DBP), and higher retinal vascular tortuosity values. In univariable linear regression analyses, older age, longer duration, higher baPWV, higher urine microalbuminuria, higher urine albumin/creatinine ratio, diagnosed with high blood pressure, thrombosis or Any DR, were significantly associated with both higher tortuosity measures (all P values
基金supported by the Key Project of Health and Family Planning Commission of Hubei Province,China(No.WJ2017Z012).
文摘Objective This study aimed to analyze the relationship between cardiorespiratory fitness(CRF)and the increasing severity of coronary artery tortuosity(CAT)in patients with non-stenosed coronaries.Methods A total of 396 patients who underwent coronary angiography and cardiopulmonary exercise testing(CPET)between August 2020 and July 2021 were included in this single-center retrospective study after excluding patients with significant coronary artery disease(≥50%stenosis).Patients were divided into two groups:no or mild coronary artery tortuosity(N/M-CAT)and moderate to severe coronary artery tortuosity(M/S-CAT)and laboratory electrocardiographic,echocardiographic,and CPET parameters were compared between two groups.Results M/S-CAT was found in 46.9%of the study participants,with 66.7%being women.M/S-CAT was significantly associated with advanced age(P=0.014)and females(P=0.001).Diastolic dysfunction parameters,E velocity(P=0.011),and E/A ratio(P=0.004)also revealed significant differences between the M/S-CAT group and N/M-CAT group.VO2@peak(1.22±0.39 vs.1.07±0.39,P<0.01)and VO2@AT(0.77±0.22 vs.0.71±0.21,P=0.017)were significantly lower in the M/S-CAT group than in the N/M-CAT group.Multivariate logistic regression analysis identified females(OR=0.448;95%CI,0.296–0.676;P=0.000)and E/A ratio(OR=0.307;95%CI,0.139–0.680;P=0.004)to be independent risk factors of M/S-CAT and showed no association of CPET parameters to M/S-CAT.Conclusion The results indicate that increasing severity of CAT is strongly associated with female gender and E/A ratio and is not directly correlated with decreasing CRF.Further research with a larger patient population and a longer follow-up time is required to fully comprehend the impact of CAT on CRF.
文摘The aim of the research is to study the propagation of a hydraulic fracture with tortuosity due to contact areas between touching asperities on opposite crack walls. The tortuous fracture is replaced by a model symmetric partially open fracture with a hyperbolic crack law and a modified Reynolds flow law. The normal stress at the crack walls is assumed to be proportional to the half-width of the model fracture. The Lie point symmetry of the nonlinear diffusion equation for the fracture half-width is derived and the general form of the group invariant solution is obtained. It was found that the fluid flux at the fracture entry cannot be prescribed arbitrarily, because it is determined by the group invariant solution and that the exponent n in the modified Reynolds flow power law must lie in the range 2 < <em>n</em> < 5. The boundary value problem is solved numerically using a backward shooting method from the fracture tip, offset by 0 < <em>δ</em> <span style="white-space:nowrap;">≪</span> 1 to avoid singularities, to the fracture entry. The numerical results showed that the tortuosity and the pressure due to the contact regions both have the effect of increasing the fracture length. The spatial gradient of the half-width was found to be singular at the fracture tip for 3 < <em>n</em> < 5, to be finite for the Reynolds flow law <em>n</em> = 3 and to be zero for 2 < <em>n</em> < 3. The thin fluid film approximation breaks down at the fracture tip for 3 < <em>n</em> < 5 while it remains valid for increasingly tortuous fractures with 2 < <em>n</em> < 3. The effect of the touching asperities is to decrease the width averaged fluid velocity. An approximate analytical solution for the half-width, which was found to agree well with the numerical solution, is derived by making the approximation that the width averaged fluid velocity increases linearly with distance along the fracture.
基金This work was financially supported by the Program of Sci-ence and Technology International Cooperation Project of Qing-hai Province(No.2022-HZ-807)Young Elite Scientist Sponsorship Program by CAST(No.YESS20200103)Fundamental Research Funds for the Central Universities(No.2652019033).
文摘The sluggish K^(+)kinetics and structural instability of the generally-used graphite and other carbon-based materials hinder the development of potassium-ion batteries(PIBs)for high-rate capability and long-term cycling.Herein,inspired by the unique flake structure and chemical composition of cytomembrane and cytoderm,we design high-tortuosity holey graphene as a highly efficient anode for PIBs.The flake cytomembrane and cytoderm shrink into wrinkled morphology during drying and sintering and then convert into high-tortuosity graphene after oxidative exfoliating and thermal reducing process.Mean-while,the proteins,sugars,and glycolipids embedded in cytomembrane and cytoderm can in-situ form nanoholes with highly abundant oxygenic groups and heteroatoms around,which can be easily removed and finally the high-tortuosity holey graphene is obtained after a thermal reducing process.The stress distribution after K^(+)intercalation confirms the optimized release of strain caused by the volume change through the finite element method.Benefiting from the unique nanoholes shortening the ion-diffusion length,the synergy of wrinkled and holey structure stabilizing volume fluctuation,and the enhanced electronic conductivity and specific surface area,the high-tortuosity holey graphene demonstrates high reversible capacities of 410 mAh g^(-1)at 25 mA g^(-1)after 150 cycles and retains 91.5%at 2 A g^(-1)after 2500 cycles.
基金financially supported by the National Natural Science Foundation of China (Nos.22175103 and 22178191)。
文摘Abundant FeS2 with high theoretical capacity is one of the promising anode candidates in sodium-ion batteries(SlBs),however,the uneven sodium deposition due to the poor interface compatibility and sluggish reaction kinetics because of the high activation barrier still plague its practical application.Herein,we synthesized the ordered porous carbon matrix wrapped FeS2 nanoparticles(FeS_2@OCN)with high sodium wettability and low pore tortuosity to economically enhance the interface compatibility as well as to lower the energy barrier in SIBs.The synergistic effects of low tortuosity pores and strong sodium wettability homogenize the Na+flux distribution,bring the electron dislocation via the enrichment of edgenitrogen(Pyridinic N and Pyrrolic N),thus achieving the dendrite-free sodium deposition and dramatically enhanced reaction kinetics.Benefiting from exceptional structural/compositional/electronic merits,the resultant anode is endowed with exceptional structure stability,achieving long-term cycling stability of 451.9 mAh·g^(-1)after 1000cycles at 1 A·g^(-1)with specific capacity retention of 92.9%.Attenuated electrode tortuosity and high sodium wettability can corporately improve the interface compatibility and attenuate the activation barrier of the FeS_2 host and beyond.
文摘The path tortuosity t is an indicator of rill morphology accounting for the deviation of the thalweg from a straight alignment.The effect of t on flow resistance has been little investigated for rills.This paper reports the results of a plot investigation aimed to establish the suitable accuracy of the rill thalweg measurement to determine the tortuosity parameter and to test the reliability of a theoretical flow resistance law.Four rills were incised in clay soil(CS)and clay-loam soil(LS)and shaped by a clear flow discharge.The three-dimensional Digital Terrain Models were created by the Structure from Motion technique.For rills on LS,an approximate thalweg was tracked by photo-interpretation,and a specific calculation routine was applied to identify the cross sections with a constant spacing d.The actual rill thalweg was obtained as the line joining the lowest points of these cross-sections.Among the different tested d values,d=0.075 m was chosen to determine t.For both CS and LS,the Darcy-Weisbach friction factorffeatured a non-monotonic relation with t,which was explained as the result of three additive components due to bed roughness,sediment transport,and localized energy losses due to curves.The effect of the former two components onff contrasts that of the third,resulting in a linearly decreasing f-t relationship and constant flow velocity for the three lowest tortuosity values,and an increased friction factor and reduced flow velocity for the highest tortuosity value.The flow resistance law was positively tested,and the predicted friction factor was dependent on t.
基金Supported by the National Natural Science Foundation of China(52274048)Beijing Natural Science Foundation Project of China(3222037)Shaanxi Provincial Technical Innovation Project of China(2023-YD-CGZH-02).
文摘Based on the tortuous capillary network model,the relationship between anisotropic permeability and rock normal strain,namely the anisotropic dynamic permeability model(ADPM),was derived and established.The model was verified using pore-scale flow simulation.The uniaxial strain process was calculated and the main factors affecting permeability changes in different directions in the deformation process were analyzed.In the process of uniaxial strain during the exploitation of layered oil and gas reservoirs,the effect of effective surface porosity on the permeability in all directions is consistent.With the decrease of effective surface porosity,the sensitivity of permeability to strain increases.The sensitivity of the permeability perpendicular to the direction of compression to the strain decreases with the increase of the tortuosity,while the sensitivity of the permeability in the direction of compression to the strain increases with the increase of the tortuosity.For layered reservoirs with the same initial tortuosity in all directions,the tortuosity plays a decisive role in the relative relationship between the variations of permeability in all directions during pressure drop.When the tortuosity is less than 1.6,the decrease rate of horizontal permeability is higher than that of vertical permeability,while the opposite is true when the tortuosity is greater than 1.6.This phenomenon cannot be represented by traditional dynamic permeability model.After the verification by experimental data of pore-scale simulation,the new model has high fitting accuracy and can effectively characterize the effects of deformation in different directions on the permeability in all directions.
基金This work is supported by the National Basic Research Program of China(Grant No.2006CB705804)the National Natural Science Foundation of China(Grant No.60773195).
文摘In this paper,we simulate the pressure driven fluid flow at the pore scale level through 2-D porous media,which is composed of different curved channels via the lattice Boltzmann method.With this direct simulation,the relation between the tortuosity and the permeability is examined.The numerical results are in good agreement with the existing theory.
基金financially supported under the Program Management Unit for National Competitiveness Enhancement (PMUC) by the Office of the National Higher Education Science Research and Innovation Policy Council (NXPO) PTT Public Company LimitedIRPC Public Company Limited, Thailand Science Research and Innovation (TSRI) under the Fundamental Fund by TSRI (FRB660004/0457)+2 种基金Vidyasirimedhi Institute of Science and Technology (VISTEC)Energy Policy and Planning Office (EPPO), Ministry of Energy, Thailandthe Frontier Research Centre (FRC) supported this work, VISTEC。
文摘This study explored the complex effect of graphite tortuosity on the electrochemical performance of Ni-rich NCA90 Li-ion batteries(LIBs).Different levels of graphite anode tortuosity were analyzed,revealing that low-tortuosity electrodes had better graphite utilization.The in-plane tortuosities of the graphite anode electrodes examined were 1.70,1.94,2.05,and 2.18,while their corresponding through-plane tortuosities were 4.74,6.94,8.19,and 9.80.In-operando X-ray diffraction and differential electrochemical mass spectrometry were employed to investigate the charge storage mechanism and gas evolution.The study revealed that while graphite electrode tortuosity impacted the amount of Li present in the lithiated graphite phase due to diffusion constraints,it did not affect gas generation.The Li-ion utilization in low-tortuosity electrodes was higher than that in high-tortuosity electrodes because of solid-diffusion limitations.Additionally,the galvanostatic intermittent titration technique(GITT) was employed to investigate a lithium-ion diffusion coefficient.Our results indicate that the lithium-ion diffusion coefficient exhibits a significant difference only during LiC_(6) phase transition.We also observed that the use of a lower tortuosity electrode leads to improved lithium-ion insertion.Consequently,graphite utilization is influenced by the porous electrode design.Safety tests adhering to UN38.3 guidelines verified battery safety.The study demonstrated the practical application of optimized NCA90 LIB cells with diverse graphite electrode tortuosities in a high-performance Lamborghini GoKart,paving the way for further advancements in Ni-rich LIB technology.
基金supported by the National Natural Science Foundation for Youths of China(Grant No.12201374)the Scientific Research Foundation of Education Department of Shaanxi Province(Grant No.22JK0315)+2 种基金the Research Foundation for the Doctoral Program of Shaanxi University of Technology(Grant No.SLGRCQD2136)the Key R&D Plan,Shaanxi Province(2022GY-138)the Science and Technology Plan Project,Guizhou Province([2022]ZD005).
文摘Understanding the integrated transport behavior of oil in shale nanopores is critical to efficient shale oil development. In this paper, based on the time-dependent Poiseuille flow momentum equation, we present a novel transient model to describe oil transport in unsteady and steady states. The model incorporates the effect of the critical shift density, apparent viscosity, slip length, and alkane property, as well as pore tortuosity and surface roughness. We evaluated our model through a comparison with other models, experiments, and molecular dynamics simulations. The results show that the development rates of the volume flows of C_(6)–C_(12) alkane confined in inorganic nanopores and C_(12) alkane confined in organic nanopores were faster than that of the corresponding bulk alkane. In addition, the critical drift density positively promoted the volume flow development rate in the unsteady state and negatively inhibited the mass flow rate in the steady state. This effect was clearest in pores with a smaller radius and lower-energy wall and in alkane with shorter chain lengths. Furthermore, both the nanoconfinement effect and pore structure determined whether the volume flow enhancement rate was greater than or less than 1. The rate increased or decreased with time and was controlled mainly by the nanoconfinement effect. Moreover, as the wall energy increased, the flow inhibition effect increased;as the carbon number of alkane increased, the flow promotion effect increased. The results indicate that the proposed model can accurately describe oil transport in shale nanopores.
文摘BACKGROUND A carotid-cavernous fistula(CCF)is an abnormal connection between the internal carotid artery(ICA)and the cavernous sinus.Although direct CCFs typically result from trauma or as an iatrogenic complication of neuroendovascular procedures,they can occur as surgery-related complications after mechanical thrombectomy(MT).With the widespread use of MT in patients with acute ischemic stroke complicated with large vessel occlusion,it is important to document CCF following MT and how to avoid them.In this study,we present a case of a patient who developed a CCF following MT and describe in detail the characteristics of ICA tortuosity in this case.CASE SUMMARY A 60-year-old woman experienced weakness in the left upper and lower limbs as well as difficulty speaking for 4 h.The neurological examination revealed left central facial paralysis and left hemiplegia,with a National Institutes of Health Stroke Scale score of 9.Head magnetic resonance imaging revealed an acute cerebral infarction in the right basal ganglia and radial crown.Magnetic resonance angiography demonstrated an occlusion of the right ICA and middle cerebral artery.Digital subtraction angiography demonstrated distal occlusion of the cervical segment of the right ICA.We performed suction combined with stent thrombectomy.Then,postoperative angiography was performed,which showed a right CCF.One month later,CCF embolization was performed,and the patient’s clinical symptoms have significantly improved 5 mo after the operation.CONCLUSION Although a CCF is a rare complication after MT,it should be considered.Understanding the tortuosity of the internal carotid-cavernous sinus may help predict the complexity of MT and avoid this complication.
文摘Pore network,pore connectivity,and the resulting effective adsorbate pore diffusivity within an adsorbent are critical physical considerations in mass transport modeling of aqueous adsorption.Tied to these three adsorbent features are the adsorbent tortuosity and tortuosity factor concepts.These concepts encompass the collective hindrance to intra-adsorbent adsorbate transport arising because of a disorderly adsorbent porous topology.It is crucial for materials scientists,chemists,chemical engineers,and water treatment specialists to understand the complex and variable connections among adsorbate chemistry,adsorbent chemistry,adsorbent porosity,pore shape,size,and tortuosity,pore wall effect,adsorbate-adsorbent interactions,and adsorbate-adsorbate interactions in competitively contaminated aqueous environments.Adsorbent tortuosity has been sporadically studied in aqueous adsorption models.Despite the small population of these studies,insightful observations and inferences have been reported.However,as it appears,no review has been published to compile,compare,and contrast these aspects.Hence,this review concisely brings up those observations and interpretations around adsorbent tortuosity for aqueous adsorption systems.The notion of an adsorbent's tortuosity being single-valued is argued to be imprecise.Finally,perspectives are aired on possible research and development directions for elucidating the dynamic attributes of adsorbent tortuosity and applying them in real-scale adsorption-oriented water purification.The data acquired by filling in these research gaps can enable the design of adsorbents more adapted for real-scale water purification.
基金supported by the research start-up and the MWU’s intramural grant(to MF)the Italian MURST-MIUR foundation(to SG and IP)
文摘Neurotrophins play a major role in the regulation of neuronal growth such as neurite sprouting or regeneration in response to nerve injuries. The role of nerve growth factor, neurotrophin-3, and brain-derived neurotrophic factor in maintaining the survival of peripheral neurons remains poorly understood. In regenerative medicine, different modalities have been investigated for the delivery of growth factors to the injured neurons, in search of a suitable system for clinical applications. This study was to investigate the influence of nerve growth factor, neurotrophin-3 and brain-derived neurotrophic factor on the growth of neurites using two in vitro models of dorsal root ganglia explants and dorsal root ganglia-derived primary cell dissociated cultures. Quantitative data showed that the total neurite length and tortuosity were differently influenced by trophic factors. Nerve growth factor and, indirectly, brain-derived neurotrophic factor stimulate the tortuous growth of sensory fibers and the formation of cell clusters. Neurotrophin-3, however, enhances neurite growth in terms of length and linearity allowing for a more organized and directed axonal elongation towards a peripheral target compared to the other growth factors. These findings could be of considerable importance for any clinical application of neurotrophic factors in peripheral nerve regeneration. Ethical approval was obtained from the Regione Piemonte Animal Ethics Committee ASLTO1(file # 864/2016-PR) on September 14, 2016.
基金supported by the National Natural Science Foundation of China(No.52174004 and No.51804318)the National Key Research and Development Program of China(No.2018YFC0808401)
文摘The use of mechanical drilling in accessing energy resources stored in deep and hard rock formations is becoming increasingly challenging.Thus,laser irradiation has emerged as a novel drilling method with considerable in this context.This study examines the variation of rock fracture length,fracture tortuosity,hole size,and rock breaking efficiency for a different number of holes and laser power,based on the constant total energy of laser irradiation.As indicated by the results,increasing the laser power increases the laser intensity,which helps increase the hole diameter and depth.Moreover,for the same laser power,increasing the number of irradiated holes reduces the laser energy absorbed by each hole,which is not conducive to increasing the hole depth.As the number of holes increases,the mass loss of the rock also increases,while both specific energy(SE)and modified specific energy(MSE)decrease.When the number of holes remains the same,the mass of the shale removed by low power is less than that removed by high power,while SE and MSE have an inverse relation with power.Therefore,high laser power and multiple-hole irradiation are more conducive to rock breaking.Besides,the fracture length and fracture tortuosity of the rock irradiated by the low laser power will increase first and then decrease with the increase in the number of holes,and reach the peak value when the irradiation takes place through three holes.When a high-power laser irradiates the rock,the fracture length and tortuosity will increase with the increase in the number of irradiation holes.This is because a rock irradiated by low power dissipates more energy,with the result that the energy absorbed by the sample with four irradiation holes is not enough to break the rock quickly.This study is expected to provide some guidance to break rock for drilling deep reservoirs and hard rock formations using laser irradiation.
文摘Several theories point to the influence of the geometry of femoral arterial bifurcation in the formation and evolution of atherosclerosis plaques at the level of common, superficial and deep femoral arteries. The objective of this study is to correlate the degrees of calcifications of the femoral tripod with different morphological parameters, namely conicity, tortuosity, proximal and distal diameters of the arteries and angles between the common femoral artery (CFA) and the superficial femoral artery (SFA) and the profound femoral artery (PFA) and the superficial femoral artery. The results showed that only the tortuosity of the common femoral artery influences the formation of atherosclerosis plaque. These results allow us to predict the degree of calcification of the femoral tripod based on the tortuosity of the common femoral artery.
文摘A fractal pore diffusion model of fiuidS in porous media which is in good agreement with the experimental data of the coke-CO2 reaction, has been derived by using the Mandelbrot’s fractal length-area relation. Based on the model, a new formula and its interpretation about the tortuosity of pore structures of a porous medium have been suggested, from which the fructal pore dthesion resistance has been defined. The resistance ascends obviously with the fmctal pore dimension and the conversion rutio increasing, especially in the middle-latter period of fiuid-solid reactions.
基金supported by the National Nature Science Foundation of China (Grant No:91534120)。
文摘Internal diffusion of molecules in porous materials plays an important role in many chemical processes.However, the pore diffusion capacity of porous materials cannot be measured by conventional catalyst characterization methods. In the present paper, a pore diffusion factor, the ratio of the diffusionconstriction factor to the pore tortuosity of the porous materials, was proposed to measure the diffusion ability of pores inside solid materials, and a method was proposed for measuring the diffusion factor using a well-defined and uniform pore size material as a reference. The diffusion factor was calculated based on the effective diffusion coefficients and the diffusion-constriction factor and pore tortuosity of the reference porous materials. The pore diffusion factor measurement can be performed at room temperature and atmospheric pressure. The pore diffusion factor of conventional porous materials was found to be much smaller than 1, indicating that there is a lot of room for improving the diffusion ability of the conventional catalysts and adsorbents, and could be significantly increased through adding small number of fibers into the conventional porous materials as template.
文摘We present a case of a patient who presented with chest pain,and on diagnostic coronary angiography appeared to have a grossly angulated yet significant coronary stenosis.This was proven to be an artefactual appearance on further assessment with intravascular ultrasound imaging.We describe the causes and associations of coronary tortuosity with other arteriopathy,and highlight challenges in the interpretation of tortuous vessels to accurately assess luminal narrowing and suitability for coronary intervention.We describe a case of artefactual coronary stenosis,and its thorough assessment with intravascular ultrasound.A literature review describes the pathogenesis of coronary tortuosity,and links with other cardiovascular disease.Readers will gain an understanding of the challenge in determining the severity of luminal stenosis based on coronary angiography alone in tortuous coronary anatomy,the use of intravascular ultrasound in this setting,and the allied vasculopathies of interest.
基金supported by SABIC Chair in Catalysis, Chemical and Materials Engineering Department, Faculty of Engineering, King Abdulaziz University, Kingdom of Saudi Arabia
文摘A chromatographic method and a dynamic Wicke-Kallenbach method (DMWK) were used to determine the diffusion characteristics of two industrial copper containing catalysts. The first catalyst was used in nitrobenzene hydrogenation to aniline and the second was used in a low temperature water-gas shift reaction. Experimental results show that application of these two methods leads to similar results. Experimental data obtained allow for monitoring changes in the texture of the catalyst grains and intraparticle diffusivity of gaseous reagents at different states of the catalyst activity and use, which can be used as criteria for designing optimal industrial catalyst pellets.