Increase In Pressure Gradient Research Articles

Injection of Recombinant Tissue Plasminogen Activator into Extracorporeal Membrane Oxygenators Postpones Oxygenator Exchange in COVID-19.

Coronavirus disease 2019 (COVID-19) has drastically increased the number of patients requiring extracorporeal life support. We investigate the efficacy and safety of low-dose recombinant tissue-type plasminogen activator (rtPA) injection into exhausted oxygenators to delay exchange in critically ill COVID-19 patients on veno-venous extracorporeal membrane oxygenation (V-V ECMO). Small doses of rtPA were injected directly into the draining section of a V-V ECMO circuit. We compared transmembrane pressure gradient, pump head efficiency, membrane arterial partial oxygen pressure, and membrane arterial partial carbon dioxide pressure before and after the procedure. Bleeding was compared with a matched control group of 20 COVID-19 patients on V-V ECMO receiving standard anticoagulation. Four patients received 16 oxygenator instillations with rtPA at 5, 10, or 20 mg per dose. Administration of rtPA significantly reduced transmembrane pressure gradient (Δ pm = 54.8 ± 18.1 mmHg before vs . 38.3 ± 13.3 mmHg after, p < 0.001) in a dose-dependent manner (Pearson's R -0.63, p = 0.023), allowing to delay oxygenator exchange, thus reducing the overall number of consumed oxygenators. rtPA increased blood flow efficiency η (1.20 ± 0.28 ml/revolution before vs . 1.24 ± 0.27 ml/r, p = 0.002). Lysis did not affect membrane blood gases or systemic coagulation. Minor bleeding occurred in 2 of 4 patients (50%) receiving oxygenator lysis as well as 19 of 20 control patients (95%). Lysis of ECMO oxygenators effectively delays oxygenator exchange, if exchange is indicated by an increase in transmembrane pressure gradient. Application of lysis did not result in higher bleeding incidences compared with anticoagulated patients on V-V ECMO for COVID-19.

Correlation of pressure gradient in three hepatic veins with portal pressure gradient.

BACKGROUNDThe liver is one of the most important organs in the human body, with functions such as detoxification, digestion, and blood coagulation. In terms of vascular anatomy, the liver is divided into the left and the right liver by the main portal vein, and there are three hepatic efferent veins (right, middle, and left) and two portal branches. Patients with impaired liver function have increased intrahepatic vascular resistance and splanchnic vasodilation, which may lead to an increase in the portal pressure gradient (PPG) and cause portal hypertension (PHT). In order to measure the increased pressure gradient of portal vein, the hepatic venous pressure gradient (HVPG) can be measured to reflect it in clinical practice. The accuracy of PPG measurements is directly related to patient prognosis.AIMTo analyze the correlation between HVPG of three hepatic veins and PPG in patients with PHT.METHODSFrom January 2017 to December 2019, 102 patients with PHT who met the inclusion criteria were evaluated during the transjugular intrahepatic portosystemic shunt procedure and analyzed.RESULTSThe mean HVPG of the middle hepatic vein was 17.47 ± 10.25 mmHg, and the mean HVPG of the right and left hepatic veins was 16.34 ± 7.60 and 16.52 ± 8.15 mmHg, respectively. The average PPG was 26.03 ± 9.24 mmHg. The correlation coefficient and coefficient of determination of the right hepatic vein, middle hepatic vein, and left hepatic vein were 0.15 and 0.02 (P = 0.164); 0.25 and 0.05 (P = 0.013); and 0.14 and 0.02 (P = 0.013), respectively. The mean wedged hepatic vein/venous pressure (WHVP) of the middle and left hepatic veins was similar at 29.71 ± 12.48 and 29.1 ± 10.91 mmHg, respectively, and the mean WHVP of the right hepatic vein was slightly lower at 28.01 ± 8.95 mmHg. The mean portal vein pressure was 34.11 ± 8.56 mmHg. The correlation coefficient and coefficient of determination of the right hepatic vein, middle hepatic vein, and left hepatic vein were 0.26 and 0.07 (P = 0.009); 0.38 and 0.15 (P < 0.001); and 0.26 and 0.07 (P = 0.008), respectively. The average free hepatic venous pressure (FHVP) of the right hepatic vein was lowest at 11.67 ± 5.34 mmHg, and the average FHVP of the middle and left hepatic veins was slightly higher at 12.19 ± 4.88 and 11.67 ± 5.34 mmHg, respectively. The average inferior vena cava pressure was 8.27 ± 4.04 mmHg. The correlation coefficient and coefficient of determination of the right hepatic vein, middle hepatic vein, and left hepatic vein were 0.30 and 0.09 (P = 0.002); 0.18 and 0.03 (P = 0.078); and 0.16 and 0.03 (P = 0.111), respectively.CONCLUSIONMeasurement of the middle hepatic vein HVPG could better represent PPG. Considering the high success rate of clinical measurement of the right hepatic vein, it can be the second choice.

The combined effects of buoyancy, rotation, and shear on phase boundary evolution

We use well-resolved numerical simulations to study the combined effects of buoyancy, pressure-driven shear and rotation on the melt rate and morphology of a layer of pure solid overlying its liquid phase in three dimensions at a Rayleigh number$Ra=1.25\times 10^5$. During thermal convection, we find that the rate of melting of the solid phase varies non-monotonically with the strength of the imposed shear flow. In the absence of rotation, depending on whether buoyancy or shear dominates the flow, we observe either domes or ridges aligned in the direction of the shear flow, respectively. Furthermore, we show that the geometry of the phase boundary has important effects on the magnitude and evolution of the heat flux in the liquid layer. In the presence of rotation, the strength of which is characterized by the Rossby number,$Ro$, we observe that for$Ro={O}(1)$, the mean flow in the interior is perpendicular to the direction of the constant horizontal applied pressure gradient. As the magnitude of this pressure gradient increases, the geometry of solid–liquid interface evolves from the voids characteristic of melting by rotating convection, to grooves oriented perpendicular or obliquely to the direction of the pressure gradient.

Performance Comparison of Cross- and Forward-Flow Configurations for Multiple-Effect Vacuum Membrane Distillation.

This work addresses retrofitting the infrastructure of multiple-effect vacuum membrane distillation (V-MEMD) units by using cross-flow configuration (CFC). In this configuration, the feed water is evenly divided and distributed over the effects. In this case, the feed water stream for each effect is kept at a high temperature and low flow rate. This will lead to an increase in the vapor pressure gradient across the hydrophobic membrane and can also maintain the thermal energy of the stream inside the individual effect. It is found that CFC improves internal and global performance indicators of productivity, energy, and exergy. A mathematical model was used to investigate the performance of such a modification as compared to the forward-flow configuration (FFC). The cross-flow configuration led to a clear improvement in the internal performance indicators of the V-MEMD unit, where specifically the mass flux, recovery ratio, gain output ratio, and heat recovery factor were increased by 2 to 3 folds. Moreover, all the global performance indicators were also enhanced by almost 2 folds, except for the performance indicators related to the heat pump, which is used to cool the cold water during the operation of the V-MEMD unit. For the heat pump system, the specific electrical energy consumption, SEEC, and the exergy destruction percentage, Ψdes, under the best-operating conditions, were inferior when the feed water flow was less than 159 L/h. This can be attributed to the fact that the heat rejected from the heat pump system is not fully harnessed.

Computational modeling and simulation of stenosis of the cerebral aqueduct due to brain tumor

ABSTRACT Stenosis of the cerebral aqueduct (CA) is featured in many studies relating to elevated intracranial cerebral pressures. It also presents a challenging situation to clinicians. Compressive forces play a lead role in pathological situations such as the presence of tumors and hence can cause obstruction to the flow of cerebrospinal fluid (CSF). Because of this barrier, excessive retention of CSF in the ventricles can occur. This, in turn, can contribute to increased pressure gradients inside the cranium. Most of the numerical models in the literature are restricted to modeling the CSF flow by considering the ventricle walls as rigid material, although in reality they are deformable. This paper, therefore, addresses the same from a holistic perspective by taking into consideration the dynamics of the flexible characteristics of the ventricular wall. It adds novelty to this field by reconstructing anatomically realistic ventricular wall behavior. To do this, the authors aim to develop a computational model of stenosis of the CA due to a brain tumor by invoking a fluid–structure interaction (FSI) method. The proposed three-dimensional FSI model is simulated under two cases: first, simulation of the pre-stenosis case with no interaction of tumor forces and, secondly, a stenosis condition with dynamic interaction of tumor forces. Comparison of the forces with and without a tumor reveals a marked obstruction of CSF outflow after the third ventricle and CA. In addition, a drastic rise in CSF velocity from 21.2 mm/s in the pre-stenosis case to 54.1 mm/s in the stenosis case is observed, along with a net increase in deformation of 0.144 mm on the walls of the ventricle. This paper makes a significant contribution to brain simulation studies for pressure calculations, in which the presence of tumors is a major concern.

Investigation of flow field, die swelling, and residual stress in 3D printing of surimi paste using the finite element method

In this research, the finite element method (FEM) was used to analyze the flow behavior in 3D printing (3DP) of surimi pastes. Additive layer manufacturing (ALM) simulation was used to analyze residual stress during and after 3DP. Rheological studies showed that the surimi paste with 82% moisture was suitable for 3DP. The FEM model revealed that a decrease in nozzle diameter (1.2–0.6 mm) increased die swell (9.8–14.1%). The rise in the swell ratio was due to an increase of pressure gradient at the nozzle exit (1.15 × 107Pa to 7.80 × 107Pa). FEM simulation indicated that the nozzle diameter influenced fluid properties (pressure, velocity, and shear rate) in the flow field as well as residual stress and deformation of the printed sample. Industrial relevanceThe development and production of food with 3-dimensional printing (3DP) technology has the potential to create and produce customized food in a more advanced format that will be a new paradigm shift in the food industry. To reach the full potential of this promising technology, methods for evaluating and predicting production outcomes must be identified. This study provides an insight into the use of the finite element method (FEM) for the prediction of printability and the deposition process of surimi paste. This method can be applied to other foods during 3DP.

Simulation models for the minimum velocity for foam generation and propagation

Foam injection is a promising means of reducing the relative mobility of gas, and hence improving the sweep efficiency of gas, in CO2 and H2 storage, soil-contaminant removal in aquifer remediation, enhanced oil recovery, and matrix-acid well stimulation. Theory (Rossen and Gauglitz, 1990; Ashoori et al., 2012) and experiments (Gauglitz et al., 2002; Yu et al., 2019, 2020) indicate that both foam generation and propagation in steady flow in porous media require the attainment of a sufficiently large superficial velocity or pressure gradient ∇P. Here we examine several foam-simulation models for their ability to represent a minimum velocity, or trigger, for foam generation. We define criteria for representation of such a trigger. For simplicity, we assume a homogeneous porous medium and absence of an oleic phase. We examine the Population-Balance (PB) models of Kam and Rossen (2003) and one of its variants (Kam, 2008), and the PB model of Chen et al. (2010); and the implicit-texture (IT) models in CMG-STARS (Computer Modeling Group, 2017) and of Lotfollahi et al. (2017).Our result show that the PB models of Kam and Rossen and its variant, and the IT models of CMG-STARS and of Lotfollahi et al. do represent a minimum velocity for foam generation. They achieve this by modeling an abrupt decrease in gas mobility with increasing pressure gradient over some range of ∇P. The model of Chen et al. (2010) is based on the model of Kovscek and Radke (1996), which was not intended to represent a trigger for foam generation (Kovscek and Radke, 1993). We cannot say categorically whether it could predict a trigger for any set of model parameter values. Instead, we derive criteria that must be satisfied by the choice of parameters to represent a trigger for foam generation.In simulations of radial foam propagation the STARS foam model predicts that foam propagation fails at the radius at which local ∇P cannot maintain strong foam, not at a greater velocity and ∇P as seen in experiments (Yu et al., 2020). In addition, we identify a fundamental challenge in representing foam generation at the large ∇P at the wellbore in a numerical simulation: conventional simulators do not represent ∇P at the wellbore. Foam generation at the very high superficial velocity at the well radius is not represented in the absence of truly exceptional grid refinement.

A case report of successful surgical treatment of mitral valve disease 38 years after implantation of ball-valve mechanical prosthesis in aortic position

The application of ball-valve prostheses in clinical practice marked a new age in the treatment of valvular heart pathology. Ball-valve prostheses are made of long-living and hard-wearing materials; however, these properties confer significant disadvantages resulting from the large dimensions and weight, increased pressure gradient and risk of valve thrombosis and systemic embolism. With the advent of more advanced disk structures, the use of ball-valve prostheses was ended.In Russia and other counties, the scientific literature shows an increase in reoperation after implantation of ball-valve prostheses over the long-term, which is associated with the occurrence of another valve defect. The need to replace a functioning ball-valve prosthesis with a modern mechanical or biological prostheses during surgery for another valve is still controversial.We present a case report of a 55-year-old patient with rheumatic mitral stenosis and functional insufficiency of the tricuspid valve, who underwent repeat surgery 38 years after implantation of a ball-valve prosthesis in the aortic position. From the echocardiography findings, the peak transmitral gradient was 16 mm Hg, the average gradient was 5.5 mm Hg, the area was 1.3 cm2 and regurgitation was third-degree. On the tricuspid valve, there was third-degree regurgitation.Adequate hemodynamic parameters of the ball-valve prosthesis (the maximum blood flow rate was 2.65 m/sec, the peak gradient was 30 mm Hg, the average gradient was 18 mm Hg and there was no regurgitation) and the absence of valve-dependent complications enabled us to perform mitral prosthetics and tricuspid valve plastic surgery without replacing the aortic prosthesis, which reduced the operation time and decreased the risk of complications.The patient was examined two years later. The patient’s active lifestyle and adequate hemodynamic parameters proved the rationality of our treatment policy.The reported case indicates that mitral valve defect that develops a long time after aortic valve prosthetics can be treated surgically without the replacement of a ball-valve prosthesis in the case that it has good function.Received 25 July 2021. Revised 22 August 2021. Accepted 23 August 2021.Funding: The study did not have sponsorship.Conflict of interest: Authors declare no conflict of interest.Contribution of the authors: The authors contributed equally to this article.

Multiscale Processes of Heavy Rainfall over East Asia in Summer 2020: Diurnal Cycle in Response to Synoptic Disturbances

Abstract Multiscale processes from synoptic disturbances to diurnal cycles during the record-breaking heavy rainfall in summer 2020 were examined in this study. The heavy rainfall consisted of eight episodes, each lasting about 5 days, and were associated with two types of synoptic disturbances. The Type-1 episodes featured a northwestward extending western Pacific subtropical high (WPSH), while the Type-2 episodes had approaching midlatitude troughs with southward retreat in the WPSH. Each heavy rainfall episode had 2–3 occurrences of nocturnal low-level jets (NLLJs), in close association with intense rainfall in the early morning. The NLLJs formed partly due to the geostrophic wind by increased pressure gradients under both types of synoptic disturbances. The NLLJs were also driven by the ageostrophic wind that veered to maximum southerlies at late night due to the boundary-layer inertial oscillation. The diurnal amplitudes of low-level southerlies increased remarkably after the onset of Type-1 episodes, in which the extending WPSH provided strong daytime heating from solar radiation. By contrast, the wind diurnal amplitudes were less changed after the onset of Type-2 episodes. The NLLJs strengthened the mesoscale mean ascent, net moisture flux convergence, and convective instability in elevated warm moist air, which led to the upscale growth of MCSs at the northern terminus of the LLJ after midnight. The MCSs-induced Meiyu rainband was re-established in Central China during the Type-1 episodes with the increased diurnal variations. The findings highlight that the regional diurnal cycles of low-level winds in response to synoptic disturbances can strongly regulate mesoscale convective activities in a downscaling manner, and thus produce heavy rainfall.

Implications of North Atlantic warming for a possible increase of dust activity in northern East Asia

This study investigates variations of the March dust activities in northern East Asia (NEA) during 1980–2021 based on dust aerosol optical thickness (DAOT) from Moder-Era Retrospective analysis for Research and Applications version 2 dataset. In particular, the roles of the atmospheric circulation and remote sea surface temperature (SST) forcing in the long-term changes of dust activities are analyzed. Results show that the NEA dust impacts on the environment have a sign of increasing on downstream East Asia, North Pacific, and even western North America. The large-scale atmospheric circulation anomalies over Eurasia play an important role in the increased dust activities over northern East Asia. A quasi-barotropic wave train from the North Atlantic to southern Asia is identified as the key atmospheric circulation factor in the variations of dust activities over the NEA. The increased pressure gradient by the wave train in the NEA strengthens the northwesterly winds and facilitates the increase of intensity and frequency of dust activities there. Further analysis indicates that the anomalous wave train is forced by the North Atlantic sea surface temperature anomalies. Sensitivity experiments with a numerical model confirm the impact of the remote SST forcing in the North Atlantic Ocean on the formation of this anomalous wave train. A linear extrapolation of the long-term decadal North Atlantic SST anomalies provides a possibility for the near-term prediction of dust activities and it suggests that the frequency and intensity of dust activities may increase in the next decade.

Instability and Transition of a Boundary Layer over a Backward-Facing Step

The development of secondary instabilities in a boundary layer over a backward-facing step is investigated numerically. Two step heights are considered, h/δo*=0.5 and 1.0 (where δo* is the displacement thickness at the step location), in addition to a reference flat-plate case. A case with a realistic freestream-velocity distribution is also examined. A controlled K-type transition is initiated using a narrow ribbon upstream of the step, which generates small and monochromatic perturbations by periodic blowing and suction. A well-resolved direct numerical simulation is performed. The step height and the imposed freestream-velocity distribution exert a significant influence on the transition process. The results for the h/δo*=1.0 case exhibit a rapid transition primarily due to the Kelvin–Helmholtz instability downstream of step; non-linear interactions already occur within the recirculation region, and the initial symmetry and periodicity of the flow are lost by the middle stage of transition. In contrast, case h/δo*=0.5 presents a transition road map in which transition occurs far downstream of the step, and the flow remains spatially symmetric and temporally periodic until the late stage of transition. A realistic freestream-velocity distribution (which induces an adverse pressure gradient) advances the onset of transition to turbulence, but does not fundamentally modify the flow features observed in the zero-pressure gradient case. Considering the budgets of the perturbation kinetic energy, both the step and the induced pressure-gradient increase, rather than modify, the energy transfer.

Effect of liver resection-induced increases in hepatic venous pressure gradient on development of postoperative acute kidney injury

BackgroundThe impact of changes in portal pressure before and after liver resection (defined as ΔHVPG) on postoperative kidney function remains unknown. Therefore, we investigated the effect of ΔHVPG on (i) the incidence of postoperative AKI and (ii) the renin-angiotensin system (RAAS) and sympathetic nervous system (SNS) activity.MethodsWe included 30 patients undergoing partial liver resection. Our primary outcome was postoperative AKI according to KDIGO criteria. For our secondary outcome we assessed the plasma renin, aldosterone, noradrenaline, adrenaline, dopamine and vasopressin concentrations prior and 2 h after induction of anaesthesia, on the first and fifth postoperative day. HVPG was measured prior and immediately after liver resection.ResultsΔHVPG could be measured in 21 patients with 12 patients HVPG showing increases in HVPG (∆HVPG≥1 mmHg) while 9 patients remained stable. AKI developed in 7/12 of patients with increasing HVPG, but only in 2/9 of patients with stable ΔHVPG (p = 0.302). Noradrenalin levels were significantly higher in patients with increasing ΔHVPG than in patients with stable ΔHVPG. (p = 0.009). Biomarkers reflecting RAAS and SNS activity remained similar in patients with increasing vs. stable ΔHVPG.ConclusionsPatients with increased HVPG had higher postoperative creatinine concentrations, however, the incidence of AKI was similar between patients with increased versus stable HVPG.

Selection and Impact of an Aerofoil Leading Edge on Boundary Layer Transition

The choice of leading-edge aspect ratio (AR) plays a crucial role when planning boundary layer wind tunnel tests on a flat plate. Poor selection of the leading-edge profile hampers effectiveness of the experiment and increases testing costs associated with interchanging of leading edges to attain accurate results. Thus, the appropriate selection of the leading edge is a very crucial part of the wind tunnel experiment process. It is argued that the curvature of the leading edge and thus the AR is of paramount importance to achieve accurate results from the wind tunnel testing. In this project, seven different elliptical leading edges were tested, and their performance was compared with an ideal leading edge with zero thickness. Experiments and computation have been done for leading edges ranging from AR6 to AR20. Results were evaluated for boundary layer transition onset location, and it was found that AR20 has the least influence on the flow structure when compared to the ideal leading edge. A study of the flow structure at the stagnation point indicates an increase in adverse pressure gradient with an increase in the AR but also shows a decrease in the size of the stagnation region. The presence of a higher AR leading edge reduces the turbulent spot production rate, which is one of the primary causes of boundary layer transition. This paper presents a correlation that enables aerodynamicists to quantify the impact of the leading-edge AR on transition. A typical case is also presented to compare the relative performance of a wedge and the higher AR leading edge, which provides a choice between an elliptical or a wedge-shaped leading edge.

Fluid-structure interaction simulation of calcified aortic valve stenosis.

Calcified aortic valve stenosis (CAVS) is caused by calcium buildup and tissue thickening that impede the blood flow from left ventricle (LV) to aorta. In recent years, CAVS has become one of the most common cardiovascular diseases. Therefore, it is necessary to study the mechanics of aortic valve (AV) caused by calcification. In this paper, based on a previous idealized AV model, the hybrid immersed boundary/finite element method (IB/FE) is used to study AV dynamics and hemodynamic performance under normal and calcified conditions. The computational CAVS model is realized by dividing the AV leaflets into a calcified region and a healthy region, and each is described by a specific constitutive equation. Our results show that calcification can significantly affect AV dynamics. For example, the elasticity and mobility of the leaflets decrease due to calcification, leading to a smaller opening area with a high forward jet flow across the valve. The calcified valve also experiences an increase in local stress and strain. The increased loading due to AV stenosis further leads to a significant increase in left ventricular energy loss and transvalvular pressure gradients. The model predicted hemodynamic parameters are in general consistent with the risk classification of AV stenosis in the clinic. Therefore, mathematical models of AV with calcification have the potential to deepen our understanding of AV stenosis-induced ventricular dysfunction and facilitate the development of computational engineering-assisted medical diagnosis in AV related diseases.

Research into changes in ship resistance in the shallow water by numerical method

Vietnam has a long coastline and dense network of rivers and canal systems with various and complicated water depths of a waterway. According to data from the Department of Inland Waterways in 2019, Vietnam's waterways transport industry reached 250 million tons/year. In which coastal transport accounted for over 60 million tons/year, promoting the shipping industry and economic integration between regions, making the most of Vietnam's natural coastal conditions. In most general cases, the vessels working in the different water depths of the operational area will significantly affect the ship and wave field resistance. For the transport vessels with low speed, the research of the effect of resistance and wave field has an essential role in ensuring the primary maritime aim of energy saving and energy efficiency. Nowadays, computation fluid dynamics is a practical approach for predicting the ship's hydrodynamic features. However, many computation fluid dynamics types of research have investigated the ship resistance in deep water, which can not consider the effect of changing ship resistance with different water depths. In shallow water, the increasing pressure gradient field leads to an increase in the overall resistance. Therefore, in this study, the volume of fluid (VOF) multiphase model can show the free surface effect and wave elevation in shallow waters. The results clearly showed the success of the computational modeling of multiphase flows around the vessel (air and water). The wavefield in the computation fluid dynamics results is also suitable for related published research experiments. Besides, the resistance and wave elevation around the hull is significantly changing at different depths. In the preliminary design stage, it can apply this work to propose a suitable hull form of transport vessels for Vietnam's waterways.

Application of Computational Fluid Dynamics (CFD) in the Deposition Process and Printability Assessment of 3D Printing Using Rice Paste

Computational fluid dynamics (CFD) was utilized to investigate the deposition process and printability of rice paste. The rheological and preliminary printing studies showed that paste formed from rice to water ratio (100:80) is suitable for 3D printing (3DP). Controlling the ambient temperature at 47±5 °C also contributed to improving the printed sample’s structural stability. The viscoelastic simulation indicated that the nozzle diameter influenced the flow properties of the printed material. As the nozzle diameter decreased (1.2 mm to 0.8 mm), the die swell ratio increased (13.7 to 15.15%). The rise in the swell ratio was a result of the increasing pressure gradient at the nozzle exit (5.48×106 Pa to 1.53×107 Pa). The additive simulation showed that the nozzle diameter affected both the residual stress and overall deformation of the sample. CFD analysis, therefore, demonstrates a significant advantage in optimizing the operating conditions for printing rice paste.

228 Management and treatment of an hypertrophic cardiomyopathy phenotype

Abstract Methods and results We are presenting the case of a 75-year-old man who was received in our Cardiomyopathy unit in 1986 with echocardiography showing evidence of left ventricular concentric hypertrophy and a subsequent diagnosis of a sarcomeric hypertrophic cardiomyopathy. During the follow-up, a progressive increase in mid-ventricular pressure gradient was reported and increasing pulmonary arterial pressure, even though the patient was asymptomatic. In 2013, the patient was hospitalized after a resuscitated cardiac arrest due to VF. The coronary angiogram did not show any significant coronary obstructions. The echocardiography showed a systolic anterior motion (SAM) of the mitral valve causing a dynamic pressure gradient in the left ventricular outflow tract reaching 90 mmHg and pulmonary hypertension (PAPs 60 mmHg). A double-chamber ICD was implanted as a secondary prevention of SCD and after a discussion with the Heart-Team, a surgical myectomy with the Morrow technique was performed on the patient. A total of 16 grams of myocardium was removed from the basal interventricular septum, three II order chordae tendineae were dissected from the AML and a mitral valve repair was performed on the patient. The myocardium was reported to show the typical aspects of infiltration; for this reason, a wide genetic analysis was performed which led to the diagnosis of Anderson–Fabry disease (a hemizygous GLA mutation and a homozygous MYBPC3 mutation). Therefore, specific enzymatic therapy was started. The genetic analysis was extended to the patient’s relatives leading to the that the patient’s brother and daughter were both carriers of the mutation. Starting in 2019, the patient began to develop symptoms of cardiac failure (mainly dyspnoea). An echocardiographic investigation showed a moderate to severe aortic regurgitation, a moderate mitral regurgitation, moderate left ventricular dilation, and pulmonary hypertension. The patient’s case was submitted to the Heart-Team’s discussion: due to the patient’s age and clinical conditions, heart transplantation was rejected and medical therapy was decided to be the best option. In 2021 the patient presented with worsening of clinical conditions including dyspnoea during daily activities (NYHA III). An echographic investigation found severe mitral regurgitation with a dilated and hypokinetic LV (EF 30%). The patient was hospitalized for decompensated HF: the coronary angiography did not show CAD and the cardiac catheterization showed low cardiac output without high vascular pulmonary resistances. After the Heart-Team re-evaluation, we decided to perform a percutaneous correction of the mitral regurgitation and in July 2021 Mitraclip implantation was performed on the patient without peri- and post-procedural complications. At the 3-month evaluation the patient was in better clinical conditions with improvement in his functional status (NYHA II). This patient is now continuing outpatient follow-up and we are considering the possibility of a future transcatheter correction of aortic valve regurgitation. Conclusions we submitted this clinical report with the aim to show how, thanks to the development of increasingly advanced diagnostic and therapeutic tools, it is nowadays possible to manage these complex phenotypes and their complications.

Effect of Deep Vibration on Physical State of Soil Being Changed

The effect of vibration on soil compaction has gained a good reputation when consolidating an artificially improved foundation. The studies aimed at analyzing the effect of the deep vibration on the properties of the compacted water-saturated soil have made it possible to establish that vibration can be an effective means of consolidation speeding-up. Vibration contributes to the emergence of additional excess pressures in the pore water; the filtration rate due to the increased pressure gradient increases as well. Consolidation speeding-up (soil compaction by squeezing out the pore water) is quite relevant. It is clear that consolidation speeding-up of foundation water-saturated soil is extremely important in site preparation for reducing site preparation time up to a period of a short summer. The study focuses on the mechanism of deep vibration (longitudinal mechanical waves) having an effect on water-saturated soil consolidation. The mechanism is based on the changed physical state of the medium and takes into account its structure. Two soil models have been proposed. The first one-parameter soil model is called a

Leakage dynamics of fault zones: experimental and analytical study with application to CO2 storage

Fault zones have the potential to act as leakage pathways through low permeability structural seals in geological reservoirs. Faults may facilitate migration of groundwater contaminants and stored anthropogenic carbon dioxide (CO $_2$ ), where the waste fluids would otherwise remain securely trapped. We present an analytical model that describes the dynamics of leakage through a fault zone cutting multiple aquifers and seals. Current analytical models for a buoyant plume in a semi-infinite porous media are combined with models for a leaking gravity current and a new model motivated by experimental observation, to account for increased pressure gradients within the fault due to an increase in Darcy velocity directly above the fault. In contrast to previous analytical fault models, we verify our results using a series of analogous porous medium tank experiments, with good matching of observed leakage rates and fluid distribution. We demonstrate the utility of the model for the assessment of CO $_2$ storage security, by application to a naturally occurring CO $_2$ reservoir, showing the dependence of the leakage rates and fluid distribution on the fault/aquifer permeability contrast. The framework developed within this study can be used for quick assessment of fluid leakage through fault zones, given a set of input parameters relating to properties of the fault, aquifer and fluids, and can be incorporated into basin-scale models to improve computational efficiency. The results show the utility of using analytical methods and reduced-order modelling in complex geological systems, as well as the value of laboratory porous medium experiments to verify results.

Experimental investigation on the evolution of damage and seepage characteristics for red sandstone under thermal–mechanical coupling conditions

Rock masses in underground space usually experience the coupling of high-temperature field, stress field and seepage field, which gives them complex mechanical behavior and permeability characteristics. To study the mechanical properties and permeability characteristics of red sandstone under different temperature environments, a seepage test under high temperature and triaxial compression is carried out based on the RLW-2000 multi-field coupling tester. The results show that the plastic flow of red sandstone at the stress peak under the same temperature is more obvious with the increase of confining pressure. In addition, as the confining pressure gradient increases, the permeability decreases and the trend becomes slower. And the higher the operating temperature, the easier to produce seepage channels inside the rock sample. The development of fissures is rapidly developed under the effect of temperature, so the seepage channels are widened and increased, and the permeability is greatly increased. The constitutive model of rock statistical damage considering the interaction of high temperature and osmotic pressure was constructed based on the experimental data and combining theoretical methods to reveal the characteristics of permeability evolution induced by thermal damage of rocks. The research results can be used as a reference for monitoring rock stability during geological engineering projects involving thermal–seepage–stress coupling conditions.