Jet Area Research Articles

Mechanism of improvement in atrial functional mitral regurgitation after catheter ablation for atrial fibrillation: Three-dimensional analysis using multislice computed tomography.

Several factors associated with atrial functional mitral regurgitation development have been reported; however, geometric changes in the mitral apparatus after catheter ablation for atrial fibrillation have not been sufficiently investigated. This study aimed to clarify what determines improvements in atrial functional mitral regurgitation after sinus rhythm restoration in patients who underwent catheter ablation for atrial fibrillation by using multislice computed tomography. We analysed volumetric multislice computed tomography images of 44 atrial fibrillation patients with significant atrial functional mitral regurgitation (moderate or worse) before and after catheter ablation. We measured the three-dimensional geometry of the mitral apparatus including the mitral annular area and interpapillary muscle distance. We calculated the differences before and after catheter ablation (Δmitral annular area, Δinterpapillary muscle distance) and assessed mitral regurgitation severity based on the mitral regurgitant jet area and its changes before and after catheter ablation (Δjet area) using transthoracic echocardiography. After catheter ablation, the jet area was significantly decreased. The left ventricular ejection fraction was significantly increased and the left ventricular volume had a decreasing trend. The Δjet area was significantly correlated with the Δinterpapillary muscle distance (r = .43; p = .004). The Δinterpapillary muscle distance was the strongest determinant of improvements in atrial functional mitral regurgitation severity (p = .026). Decreased interpapillary muscle distance was strongly associated with improvements in atrial functional mitral regurgitation. Amelioration of left ventricular dysfunction by sinus rhythm restoration might be related to improvements in atrial functional mitral regurgitation after catheter ablation.

Heat and drag reduction of single and combined opposing jets in hypersonic nonequilibrium flows

To establish a method of achieving effective thermal protection and drag reduction in hypersonic flows with an opposing jet under a low flow rate, this study compared three single and two combined jets. For a single jet, nozzles of different sizes (nozzles 1, 2, and 3) were investigated. The influence of the effective area of the annulus jet was studied for the combined jet, consisting of a circular jet and an annulus jet. A 2.6%-scale Apollo capsule was investigated with these jets in hypersonic flows at Mach 19 and an altitude of 60 km using a transient numerical method. Considering nonequilibrium effects (vibrational excitation and chemical reactions), the heat and drag reduction mechanisms of these single and combined jets in hypersonic flows were explored using a nonequilibrium Navier–Stokes–Fourier numerical approach. The results indicated that nonequilibrium effects exist in the shock wave and wake regions. The size of the nozzle in the single jet and the effective area of the annulus jet in the combined jet influence the heat and drag reduction. A single jet with an excessively small nozzle size considerably decreases the effects of heat and drag reduction. Compared with a single jet, the combined jet cannot reduce the aerodynamic drag at a low flow rate owing to the dispersion of the jet. However, a combined jet with a larger area of the annulus jet can effectively reduce the aerodynamic heat to 68%, whereas three single jets can considerably enhance the surface heat flux.

Cavitation optimization of single-orifice plate using CFD method and neighborhood cultivation genetic algorithm

Single-orifice plate is wildly utilized in the piping system of the nuclear power plant to throttle and depressurize the fluid of the pipeline. The cavitation induced by the single-orifice plate may cause some serious vibration of the pipeline. This study aims to find the optimal designs of the single-orifice plates that may have weak cavitation possibilities. For this purpose, a new single-orifice plate with a convergent-flat-divergent hole was modeled, a multi-objective optimization method was proposed to optimize the shape of a single-orifice plate, while computational fluid dynamics method was adopted to obtain the fluid physical quantities. The reciprocal cavitation number and the developmental integral were treated as cavitation indexes (e.g., objectives for the optimization algorithm). Two non-dominant designs ultimately achieved illustrated obvious reduction in the cavitation indexes at a Reynolds number Re = 1 × 105 defined based on fluid velocity. Besides, the sensitivity analysis and temperature effects were also performed. The results indicated that the convergent angle of the single-orifice plate dominants the cavitation behavior globally. The optimal designs of single-orifice plates result in lower downstream jet areas and lower upstream pressure. For a constant Reynolds number, the higher temperature of liquid water, the easier it is to undergo cavitation. Whereas there is a diametric phenomenon for a constant fluid velocity. Moreover, the regression models were carried out to establish the mathematical relation between temperature and cavitation indexes.

General Anesthesia Leads to Underestimation of Regurgitation Severity in Patients With Secondary Mitral Regurgitation Undergoing Transcatheter Mitral Valve Repair

To evaluate the effect of general anesthesia (GA) on severity of mitral regurgitation (MR) in patients undergoing transcatheter mitral valve repair (TMVR). Retrospective cohort study. Tertiary care university hospital. Fifty consecutive patients with symptomatic severe MR and extremely high surgical risk. TMVR under GA. Transesophageal echocardiography was performed during the preprocedural workup under conscious sedation and during TMVR under GA. After the parameters of MR were assessed, color-flow jet area (CJA), vena contracta (VC), effective regurgitant orifice area (EROA), regurgitant volume (RVOL), three-dimensional (3D) vena contracta area (VCA), and severity of MR were compared between the two examinations. In patients with primary MR (n=11), there were no significant differences in CJA, VC, EROA, RVOL, or 3D-VCA between pre- and intraprocedural transesophageal echocardiography. In patients with secondary MR (n=39), GA led to significant decreases of CJA (10 ± 7 v 7 ± 3 cm², p < 0.001), VC (5.5 ± 1.6 v 4.7 ± 1.5 mm, p=0.002), EROA (30 ± 11 v 24 ± 10 mm², p < 0.001), and RVOL (47 ± 17 v 34 ± 13 mL/beat, p < 0.001). Consequently, GA led to a downgrade of regurgitation severity classification in 44% of patients when assessed by two-dimensional analysis. When evaluated by 3D analysis, GA also led to a significant but less extensive decrease of MR (3D-VCA: 66 ± 27 v 60 ± 29 mm², p=0.002), and subsequent downgrade of MR classification in 20% of patients. GA underestimates regurgitation severity in patients with secondary, but not primary MR, undergoing TMVR. This effect must be considered when evaluating the immediate result of the procedure.

Valvular changes after aortic valve neo-cuspidization in children: A case series.

Aortic valve neo-cuspidization (AVNeo), a procedure wherein the aortic valve is reconstructed utilizing an autologous pericardium, has recently been more commonly performed in children. However, the postoperative morphological changes in the aortic valve of pediatric patients remain unknown. The current study aimed to describe the intraoperative and postoperative findings of aortic regurgitation (AR) and stenosis (AS) after AVNeo in children. This case series describes the morphological changes in AR and AS, and their severity, between the perioperative period and 3 months postoperative period after AVNeo in children (<18 years) who underwent AVNeo between April 2016 and March 2020. Data were collected at two measurement points: (i) intraoperative transesophageal echocardiography after weaning from cardiopulmonary bypass (io-TEE); (ii) postoperative transthoracic echocardiography 3 months after the procedure (po-TTE). Seven patients were included in this case series. The number of postoperative AR sites and the ratio of AR jet area to the left ventricular outflow tract area showed a tendency to decrease between io-TEE and po-TTE. All AR sites were integrated during the postoperative period. One patient identified developed intraoperative AS, which maintained its severity after AVNeo. Most cases exhibited spontaneous improvement in AR, while one developed postoperative AS. Further prospective investigation is, therefore, needed to explore surgical outcomes following AVNeo among children.

Impact of catheter ablation on functional tricuspid regurgitation in patients with atrial fibrillation

Abstract Background Since atrial functional tricuspid regurgitation (AF-TR) is associated with increased heart failure and mortality, the management of AF-TR is clinically important. Atrial fibrillation (AF) plays the main role in AF-TR. However, the effectiveness of catheter ablation (CA) and mechanism of improvement of AF-TR haven't been fully evaluated. Purpose We sought to investigate the impact of CA for AF on AF-TR in patients with moderate or more TR. Methods We retrospectively investigated consecutive 2685 patients with AF who received CA from February 2004 to December 2019 in Japan. The current study population consisted of 102 patients with moderate or greater TR who underwent CA for AF. The echocardiographic parameters were compared between pre-ablation and post-ablation transthoracic echocardiography (TTE), and the recurrence rate of AF/ atrial tachycardia (AT) was measured. Results The mean age was 73.2 years, 53% were women. TR severity and TR jet area significantly improved after CA for AF (TR jet area: 5.8 [3.9–7.6] cm2 to 2.0 [1.1–3.0] cm2, p&amp;lt;0.001). In addition, mitral regurgitation (MR) jet area, left atrial (LA) area, mitral valve diameter, right ventricular (RV) end-diastolic area, right atrial (RA) area, tricuspid valve (TV) diameter decreased after CA (p&amp;lt;0.001, &amp;lt;0.001, &amp;lt;0.001, = 0.02, &amp;lt;0.001, and &amp;lt;0.001, respectively). There was no significant difference between one-year recurrence of AF/AT and TR severity at pre-ablation TTE (moderate 28.6%, moderate to severe 37.2%, and severe 31.6%, p=0.72). Conclusions TR severity and jet area improved after CA in patients with AF and moderate or more TR. RV size, RA size, TV diameter also decreased after CA, which may be associated with TR improvement. There was no significant difference between one-year recurrence of AF/AT and TR severity at pre-ablation TTE. Funding Acknowledgement Type of funding sources: None.

Mitral regurgitation severity assessment after percutaneous edge-to-edge mitral valve repair: guidelines-recommended integration versus volumetric assessment

Abstract Background Percutaneous edge-to edge mitral valve repair (PMVr) using the MitraClip device is a common method for treating mitral regurgitation (MR) when mitral valve operation is contra-indicated or deemed too risky. The evaluation of residual MR post PMVr is crucial for understanding the benefit and prognostic effect on patients. The common methods used today, based on color flow Doppler and the appearance of the color Doppler jet, may be misguiding because of the multiple jets created by the PMVr technique. Also, flow acceleration induced by the reduced systolic orifice may exaggerate systolic flow acceleration and thus jet area. Purpose We hypothesized that the guidelines-recommended method to assess MR may underestimate the effect of PMVr in reducing MR. Methods Patients undergoing PMVr in a large-volume PMVr centre were recruited between 2015–2019. Post procedural MR was evaluated using the integrated qualitative approach as recommended by the guidelines. In addition, MR volume for each patient was calculated by subtracting the forward stroke volume (calculated by multiplying LVOT area with the velocity time integral of LVOT systolic flow) from the total stroke volume (using the biplane method of discs), We compared the two methods for concordance. Results Overall, 112 cases were enrolled. In 59% of cases, the calculated volumetric residual MR was lower than the MR assessed by the integrated method. In 25.1% of patients the grade of MR was identical in both methods. In 16.2% the MR was more severe when calculated by the volumetric method (p&amp;lt;0.001, Kappa measure of agreement = 0.053–0.074). The reduction in residual MR degree using the volumetric approach was mostly observed in patients classified as “moderate” by the integrated qualitative approach. When considering basic characteristics and cardiac function of the patients, we did not find any sub-group of patients in whom the tendency for this mistake was higher. Conclusion Because of multiple jet origins and clip-induced flow acceleration, the integrated method to assess MR severity, based mainly on color Doppler, is not ideal in patients after PMVr. In most cases, MR severity after MitraClip is over-estimated by the integrated, guideline-recommended integrative method when compared with a volumetric method. This is especially relevant for patients classified with “moderate” MR. This study suggests that quantitative methods, not based on colour Doppler, should be used to assess MR severity after PMVr Funding Acknowledgement Type of funding sources: None.

Assessment of the effects of cardiac rhythm device implantation on right sided heart function and tricuspid valve

Abstract Objective To assess the effects of trans-tricuspid placement of permanent pacemaker (PPM), on the right-sided heart function and tricuspid valve function. Background Over the last decade there has been a significant increase in the number of cardiac device implantation as permanent pacemakers (PPM) worldwide in patients with cardiac rhythm disorders. Tricuspid regurgitation (TR) due to the endocardial lead is a known complication of this procedure, however the incidence of new or worsening TR had not been well studied. Patients and Methods We reviewed patients who underwent permanent pacemaker implantation in our cardiology department in Ain Shams University. Patients who had pacemaker implantation less than one year ago, had severe tricuspid regurgitation before implantation or had previous tricuspid valve repair were excluded. A total of one hundred patients with an echocardiographic study before and another echocardiographic study at least one year after device implantation were included in our study. TR severity was graded as (0 none/trace, 1 mild, 2 moderate, 3 severe). Results Of the 100 patients (Mean age: 53.10 ± 16.04, 50% of patients were males) 65 had DDD and 35 had VVI. Before implantation 25 patient had trace TR (grade 0) vs. 6 patients after, 75 patients had mild TR (grade 1) vs. 82 after, with no patient had moderate TR (grade 2) vs. 12 patients after. TR worsened by one grade in 25 patients, (16 patients from grade 0 to grade 1 and 9 patients from grade 1 to grade 2) and by 2 grades in 3 patients (from grade 0 to grade 2), Pvalue &amp;lt; 0.01. TR jet area size (Mean ± SD: 2.80 ± 0.77 before vs. 4.15 ± 1.29 after, P-value &amp;lt; 0.01). Also, 99 patients had normal RV size and one had dilated RV before implantation vs. 95 patient had normal RV and 5 had dilated RV (p-value= 0.097). RV size, LVEF (Mean ± SD: 56.41% ± 7.52 before vs. 55.77% ± 8.00 after), RV function by TASPE (Mean ± SD: 19.15 ± 1.00 before vs. 18.96 ± 0.96 after), RVSP (Mean ± SD: 29.48mmHg ± 5.54 before vs. 29.81 ± 5.09 after) and diastolic function by E/A ratio (Mean ± SD: 1.60 ± 0.39 before vs. 1.57 ± 0.38 after implantation) did not show significant change. Conclusion Permanent pacemaker (PPM) implantation is associated with worsening of tricuspid regurgitation. Echocardiography plays an important role in assessing and grading this condition. Further studies are needed in order to illustrate the effects of these finding on patients outcomes.

Numerical Investigation of Nozzle Jet Flow in a Pelton Microturbine

The characterization of flow through Pelton hydro turbines allows the optimization of their operation and maximization of energy performance. The flow in the injector of Pelton turbines and in the free jet area (the area from the injector outlet surface to the runner bucket inlet surface) is influenced by several parameters: the geometry of injector components (nozzle and injector spear), the injector opening, and the turbine head. The parameters of the free jet flow (velocity distribution, pressure distribution, and jet spread) are reflected in the turbine efficiency. The research presented in this paper focuses on the numerical characterization of flow in the injector and the free jet of a Pelton microturbine. Three injector geometries were considered, with different nozzle diameters: 13.3 mm, 14.4 mm, and 16.3 mm. For each of these geometries, the flow was analyzed for five values of turbine head (H = 15 m, H = 20 m, H = 25 m, H = 30 m, H = 35 m) and six values of injector opening (S = 3 mm, S = 6 mm, S = 9 mm, S = 12 mm, S = 15 mm, S = 18 mm). The results of numerical simulations were used to plot injector flow-rate characteristics and injector force characteristics (the resultant force on the injector spear and the resultant force on the injector nozzle). The highest influence on the flow rate variation is given by the variation of turbine head, followed by the variation of the injector opening and the variation of the nozzle diameter. Increasing the nozzle diameter accentuates the variation of the flow rate versus the turbine head. The variation of axial velocity and pressure in the free jet is presented for four sections parallel to the outlet section of the injector. The injector openings that generate the highest values of velocity/pressure on the runner inlet surface are highlighted. The results allow optimization of functional parameters for increasing turbine efficiency and optimizing the design process of Pelton microturbines.

Research on Nozzle Design and Application of Single‐Flow Postcombustion Oxygen Lance in a 120 t Top‐Blown Converter

The flow characteristics and postcombustion behavior of a single‐flow postcombustion (PC) oxygen lance are of paramount significance to optimal design and operation of the lance but not well understood, and there is also no well‐known design criterion for the optimization of the single‐flow PC lance. Herein, the design criteria of a single‐flow PC lance are first proposed. Then, a 3D fluid model is established combined with a 120 t top‐blown converter. The influences of the key parameters of secondary nozzles (i.e., inclination angle, diameter, and number) on the jet characteristics and PC behavior at the steelmaking temperature are studied. Finally, based on the design criteria, an optimal PC lance is designed and its smelting effect is compared with that of the conventional lance by industrial tests. The results indicate that the reasonably designed PC lance can effectively improve the PC zone of CO gas and simultaneously increase both the penetration depth and impact area of the main jet. Compared with conventional lance, the PC oxygen lance can raise the temperature of molten steel by ≈30 °C and reduce the total fe (T.Fe) content in the final slag by 0.86%. Moreover, it has almost no effect on the gas recovery.

Method for increasing upper limit of heat flux measurement of slug calorimeter in high enthalpy plasma jet

The temperature of the high-power inductively coupled plasma jet is very high, and its temperature is difficult to measure directly. The heat flux becomes a thermodynamic characteristic to measure the plasma jet. The existing heat flux calculation method is based on the temperature change rate after the response time. The slug is required to stay in the high enthalpy jet area for a longer time. With the slug temperature reaching the melting point as the upper limit, the shorter the residence time, the greater the upper limit of the measured heat flux. In this paper, the first-order transient solution is added to the steady-state solution of temperature (the calculation equation of the existing method), which can shorten the response time. The shortening of the response time can reduce the residence time of the slug in the jet region, and the reduction in the residence time can increase the upper limit of the calorimeter heat flux measurement. This paper uses numerical simulation and experimental methods to verify that the steady-state solution method and the first-order transient solution method can obtain consistent heat flux results. Using the first-order transient solution method can reduce the residence time of the slug calorimeter in the jet region. According to the shortening of the residence time, the method of using the first-order transient solution can increase the upper limit of the heat flux measurement by more than 25%.

Comparison of Triggered Steam Explosion Behavior According to Corium Injection Mode in TROI Facility from TEXAS-V Code Simulations

A steam explosion can occur when molten corium falls from the reactor vessel into the water in the reactor cavity. While various research studies have been conducted on steam explosions following the free fall of molten corium in air before entering the water, steam explosions following submerged corium discharge under the ex-vessel cooling condition have received relatively little analysis. The aim of this paper is to compare the progress and consequences of a steam explosion in experiments and simulations for the partially flooded cavity and ex-vessel cooling conditions. Three steam explosion tests carried out in the TROI (Test for Real cOrium Interaction with water) experimental facility were simulated by the TEXAS-V code. Experimental tests were first modeled, followed by a comparison of the experimental and simulation results. The effect of the molten corium mass involved in the steam explosion under water at the moment of triggering on the strength of the explosion was higher than that of the corium composition in the tests and simulations for the condition of a partially flooded cavity. In the test and simulations of different corium injection modes to the water, the maximum pressure and impulse of the steam explosion appeared in the partially flooded cavity condition. In the simulations for the partially flooded cavity condition, the mass of the molten corium fragmented by Rayleigh-Taylor instability (RTI) was higher than that fragmented by Kelvin-Helmholtz instability (KHI). Modeling of KHI fragmentation caused solidification of the fragmented corium particles, and the impulses reduced accordingly. In the simulations for the ex-vessel cooling condition, as melt jet breakup did not occur before the triggering time, simulations with only RTI fragmentation underestimated the impulse of the steam explosion. Otherwise, modeling of KHI fragmentation increased the impulse of the steam explosion due to fragmentation on the side of the corium jet. Steam explosion simulations in the ex-vessel cooling condition require more detailed modeling of the melt jet and premixing area, as well as variable adjustment for the fragmentation by KHI.

RISK STRATIFICATION OF HEART FAILURE BY ISCHEMIC MITRAL REGURGITATION IN PATIENT WITH MYOCARDIAL INFARCTION

One of the important complications which causes the increase of mortality and economic burden on patient is the ischemic MR. Its main pathophysiology is the remodeling of the LV after MI which causes the hemodynamic load and heart failure. However, the data on relationship between ischemic MR and duration of heart failure is very few. We prospectively studied 300 patients who admitted for acute myocardial infarction in our hospital. All patients were assessed by echocardiography and graded MR as mild, moderate, and severe according to regurgitant jet area which is less than 20%, 20 – 40%, and more than 40% of the left atrial area, respectively. The median duration of follow up was 1 year (range 6-12 months). Mild and moderate or severe ischemic MR was present in 40.2 and 6.4% of patients respectively. The hazard ratios for HF were 2.9 (95% condence interval (CI), 1.9–4.3; P&lt;.001) and 3.7 (95% condence interval (CI), 2.1-6.5; P&lt;.001) in patients with mild and moderate or severe ischemic MR respectively, with compared to patients without ischemic MR, after adjusting for ejection fraction and other clinical variables like age, sex, Killip class, previous infarction, hypertension, diabetes mellitus, anterior wall infarction, ST elevation infarction and coronary revascularization. In patients with mild ischemic MR, the adjusted hazard ratio for death was 1.1 (95% CI 0.7-1.7; P=.42), where as in moderate or severe ischemic MR it was 2.1 (95% CI 1.3-3.5; P=.02).

Dynamic modes of inflow jet in brain aneurysms

The transition of the inflow jet to turbulence is crucial in understanding the pathology of brain aneurysms. Previous works Le et al. (2010, 2013) have shown evidence for a highly dynamic inflow jet in the ostium of brain aneurysms. While it is highly desired to investigate this inflow jet dynamics in clinical practice, the constraints on spatial and temporal resolutions of in vivo data do not allow a detailed analysis of this transition. In this work, Dynamic Mode Decomposition (DMD) is used to identify the most energetic modes of the inflow jet in patient-specific models of internal carotid aneurysms via the utilization of high-resolution simulation data. It is hypothesized that dynamic modes are not solely controlled by the blood flow waveform at the parent artery. They are also dependent on jet-wall interaction phenomena. DMD analysis shows that the spatial extent of low- frequency modes corresponds well to the most energetic areas of the inflow jet. The high-frequency modes are short-lived and correspond to the flow separation at the proximal neck and the jet’s impingement onto the aneurysmal wall. Low-frequency modes can be reconstructed at relatively low spatial and temporal resolutions comparable to ones of in vivo data. The current results suggest that DMD can be practically useful in analyzing blood flow patterns of brain aneurysms with in vivo data.

Strategies to challenge the simulation of confined fires

The numerical simulation of fires concerns an increasingly wide range of applications, among which archaeology. The Chauvet-Pont d’Arc Cave (France) presents thermal marks on some of its walls. These marks result from prehistorical fires and archaeologists would like to know their characteristics (fire location, mass of fuel, number of fires, etc) to make assumptions about their functions. Being impossible to carry out fires in the cave, combustion simulation is a suitable tool to discuss this question. However, simulating a fire in a confined geometry is still challenging and some inherent difficulties must be overcome. In that respect, we reproduced four experimental fires in a cave-like geometry. Four tepee-like hearths, composed of different initial wood masses (16, 32, 60 and 90 kg), were burnt in an underground quarry. Twenty-seven thermocouples measured the temperature in the cold and hot gas layers, as well as in the ceiling jet area. The measurements in the ceiling jet resulting from the 90 kg fire are successfully compared to the corrected Delichatsios correlations. In addition, the measured mass loss rate is compared to a tailored modeling for tepee hearths. We alsopropose three strategies to simulate the combustion process of the 90 kg hearth: (i) with a significant refinement in the ceiling jet area (approximately 1,500,000 cells) and the law of the wall, (ii) without refinement but with Newton’s law of cooling and (iii) without refinement but with simplifying assumptions and adjustments. While the first and third approaches provide meaningful results, the second case is found to be inconvenient for compartment fires. Based on experimental data, this study aims to give some keys to perform simulations of compartment fires (in tunnels, buildings, car parks, etc) and numerically approximate the combustion of wood.

Diagnostic and Prognostic Value of Several Color Doppler Jet Grading Methods in Patients With Mitral Regurgitation

Color Doppler is a widely used ultrasound imaging method for assessing mitral regurgitation (MR) in clinical practice. Nevertheless, color Doppler-based grading of the MR jet has been rarely considered in clinical studies. We investigated the diagnostic and prognostic value of several color Doppler MR jet grading methods and compared them with quantitative grading of MR. The MR color Doppler jet was assessed in 476 MR patients using an 'integrated' eyeballing approach by quantifying the color Doppler jet area, jet area/left atrium area and jet length and using quantitative methods. Clinical endpoints were scored as major adverse clinical events, including cardiovascular death, heart failure hospitalization and mitral valve intervention. When assessed by three echocardiographers, there was a moderate inter-observer agreement for eyeballing color Doppler grade of MR (intraclass correlation coefficient 0.69, p < 0.001). The intra-observer agreement was good for all color Doppler approaches. In primary MR, eyeballing color Doppler correlated well with (in)direct measures of MR severity, with a negative predictive value of 91% when using a grade 2 color Doppler as cut-off. In secondary MR, eyeballing color Doppler grade and jet length were predictors of clinical outcome in Cox proportional hazards analysis (p = 0.003), independent of pulmonary pressures, atrial and ventricular volumes. Overall, the integrated eyeballing approach performed better than color Doppler quantification of the MR jet area and length. In conclusion, this study shows that color Doppler grading of the distal MR jet performs well in predicting events in primary and secondary MR, compared to quantitative grading methods.

ОСОБЕННОСТИ ВЕНТИЛЯЦИИ ЗРИТЕЛЬНЫХ ЗАЛОВ

The choice of air distribution scheme is the most important task which determines indoor air quality, comfort thermal mode of the room and effectiveness of ventilation systems. The article presents comparative analysis of displacement and mixing ventilation systems for large premises. The methodology of the study is based on existing theoretical provisions and standard calculation approach of supply air jets. Multivariate calculations of mixing air distribution in cinema hall are presented. Horizontal jets along room surfaces can not provide required air velocity. In the case of vertical air distribution relative jet area beyond the recommended values. This factor had thus determined the possible formation of circulation contours with high concentrations of harmful emissions. The results of the calculation shows that the speed of the fan jet at the entrance of occupied zone lower than maximum permissible air mobility. The required temperature is achieved by using all air-distributing units considered.

Investigation on Continuous and Modulated Microwave Plasma Filaments at Atmospheric Pressure

Microwave atmospheric pressure plasma jets continue to evolve with the growth of atmospheric plasma’s applications in sterilization, material modification, and cancer treatment. In this article, continuous and modulated microwave plasma filaments were produced by a hand-held microwave plasma jet, and then they were compared in plasma length, electron temperature, and emission spectrum. The electron temperature was measured by the emission spectroscopy diagnostic method, and the regularities of the compared parameters’ change were studied by varying duty cycles and periods of the modulating signal. The results prove that the modulated microwave can generate stable plasma filaments directly in the air without protective tubes, and it is different from the continuous microwave plasma in all compared parameters. Besides, stable dendritic tearing of plasma filaments was observed. These results imply that modulated microwave and continuous microwave plasma filaments cannot be regarded as the same, the changing manner and the reaction on the surface of the medium may be completely different even if they are the same to the naked eye in most cases. These results are helpful for the controlling and understanding of microwave plasma, and the stable tearing could be used to expand the treated area of a single plasma jet.

Preliminary Outcome of a Novel Edge-to-Edge Closure Device to Manage Mitral Regurgitation in Dogs.

Background: Veterinary management of mitral valve regurgitation due to mxyomatous valve disease in dogs is limited to medical treatments, which only postpones the onset of congestive heart failure or alleviates clinical symptoms. Most surgical procedures to manage this condition in humans require cardiopulmonary bypass and have a high risk of complications.Animals: Eight dogs with naturally occurring mitral valve regurgitation.Methods: Prospective observational study. All dogs were treated with a novel edge-to-edge transcatheter device named ValveClamp. The total surgical procedural time and total catheterization time were recorded. Echocardiographic variables measured pre- and post-procedure were compared using Wilcoxin-signed rank test with a P < 0.05 considered significant. Data were expressed as median and interquartile range and absolute numbers and percentages.Results: The procedural success rate was 100% and all the dogs survived without complications. The median (interquartile range) total surgical procedural time was 86.5 (76–96.2) minutes and catheterization time was 23.5 (22–33.8) minutes. Echocardiography revealed a significant reduction in mitral regurgitation severity in all dogs following the procedure based on both a reduced mitral regurgitant maximum jet area (P = 0.012) and a reduced mitral regurgitant maximum jet area to left atrial area (P = 0.018).Conclusion: The ValveClamp device is effective at reducing the severity of mitral regurgitation in dogs with naturally occurring myxomatous valve disease.

Complete theory of the elastic wall jet: A new flow geometry with revisited two-phase nanofluids

In the present research, it is solved in an innovative manner the essentially Non-Similar nanofluids jet discharged over a generalized non-linearly stretching wall. The Non-Similar set-up is interpreted as a combination of wall jet flow at the leading edge and non-linearly stretching sheet flow far away from it. Nanofluids are simulated employing Buongiorno’s two-phase model together with a modified boundary condition for nanoparticles transport equation. The compositely-transformed partial differential equations (PDE) of Non-Similar forms were solved numerically after employing a new mapping function to abridge the horizontal coordinate of an infinite length into a finite one. The numerical algorithm contains quasi-linearization technique together with an implicit algorithm of tridiagonal form. It should be pointed out that such a new Non-Similar setup is brought into account for the first time in the literature. In this respect, we summarize the outstanding novel findings of the present work as: •[I.] Accounting a modified boundary condition for nanoparticles concentration at the wall, the so-called and widely-used Brownian motion parameter, namely Nb, will have absolutely NO impact on Nusselt number or more precisely, on Energy Equation. In this respect, it is presented a new way of defining dimensionless variables.•[II.] As the stretching ratio increases, it is observed a discrepancy in boundary layer thickness; it expands close to the jet area, shrinks in the transition region and adapts the far-field condition, either by expanding or shrinking, depending on the stretching ratio.•[III.] As the stretching ratio increases, Nusselt number decreases slightly shortly after the jet origin and then increases dramatically to match the stretching region.•[IV.] As the stretching ratio increases, nanoparticles at the wall become more concentrated at the downstream and hence, close to the jet region as well as the transition region, the concentration is sparse.•[V.] As thermophoresis parameter, namely Nt, increases, convective heat transfer coefficient drops non-uniformly, from the leading edge to downstream, as well as nanoparticles concentration at the wall.•[V1.] As Schmidt number increases, convective heat transfer drops; however, nanoparticles concentration at the wall increases over the entire spatial domain.