Stability Parameters Research Articles

Experimental and numerical study of stabilized flame in inverse coflow turbulent jet using nanosecond repetitively pulsed discharges

Methane has become increasingly popular in rocket propulsion, but low stability and limited flammability range have always been a concern about methane-powered systems. Many stabilization methods have been developed to change the geometrical or flow characteristics of the burner. However, most of these efforts have yet to be practically successful due to cost and compatibility issues. Alternatively, other methods such as microwave, dielectric barrier, and nanosecond repetitive pulse (NRP) discharges have been proven to be efficient by modifying the kinetic and transport pathways. NRP discharges have shown promising results as one of the most effective low-temperature plasma (LTP) methods. In this paper, chemiluminescence imaging is used to study the effect of NRP discharge on liftoff and blowout, as the important stabilization parameters, by recording the liftoff height and liftoff/blowout velocities under a wide range of discharge (f=0–10 kHz and V=11–19 kV) and jet velocity (ν=2–60 m/s). Depending on these parameters, four different discharge regimes of corona, diffuse, filamentary, and arc were observed. The results have shown that high-intensity plasma in a filamentary discharge regime can provide a significant advantage in delaying the liftoff conditions, but no improvements in the blowout were observed. It was also found that NRP discharge can reduce the liftoff height. To explore the cause of the increased stability, a parametric numerical study is conducted using detailed plasma-assisted methane kinetic modeling coupled to a 1D opposed diffusion flame simulation. Results show that the extinction limits of diffusion flames can be dramatically enhanced by LTP due to the local formation of high radical and excited species concentrations, with subsequent recombination leading to increased temperature and higher reactivity in the flame zone. In addition, a 1D laminar flame speed evaluation shows that the plasma-generated active species can dramatically increase the flame speed, which, in turn, reduces the lifted flame height above the burner surface.

Effects of riparian pioneer plants on soil aggregate stability: Roles of root traits and rhizosphere microorganisms

Pioneer plants are vital in stabilizing soil structure while restoring reservoir drawdown areas. However, uncertainties persist regarding the mechanism of pioneer plants to soil stability in these delicate ecosystems. This study aims to unravel the plant-soil feedback mechanisms from the roles of root traits and rhizosphere microorganisms. We conducted a mesocosm experiment focusing on four common pioneer plants from the drawdown area of Three Gorges Reservoir, China. Using the wet sieving methodology, trait-based approach and high-throughput sequencing technology, we explored soil aggregate stability parameters, plant root traits and rhizosphere microbial communities in experimental plant groups. The interacting effect of pioneer plant species richness, root traits, and rhizosphere microbial communities on soil aggregate stability was quantified by statistical and machine-learning models. Our results demonstrate that diverse pioneer plant communities significantly enhance soil aggregate stability. Notably, specific species, such as Cynodon dactylon (L.) Pers. and Xanthium strumarium L., exert a remarkably strong influence on soil stability due to their distinctive root traits. Root length density (RLD) and root specific surface area (RSA) were identified as crucial root traits mediating the impact of plant diversity on soil aggregate stability. Additionally, our study highlights the link between increased rhizosphere fungal richness, accompanied by plant species richness, and enhanced soil aggregate stability, likely attributable to elevated RLD and RSA. These insights deepen our understanding of the role of pioneer vegetation in soil structure and stability, providing valuable implications for ecological restoration and management practices in reservoir drawdown areas.

A flux‐based HDG method

AbstractIn this article, we present a flux‐based formulation of the hybridizable discontinuous Galerkin (HDG) method for steady‐state diffusion problems and propose a new method derived by letting a stabilization parameter tend to infinity. Assuming an inf‐sup condition, we prove its well‐posedness and error estimates of optimal order. We show that the inf‐sup condition is satisfied by some triangular elements. Numerical results are also provided to support our theoretical results.

The novel bispecific anti-NLRP3 inflammasome antibody InflamAb inhibits atherosclerosis in apolipoprotein E-deficient mice

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Dutch Heart Foundation Background/Introduction Atherosclerosis is the underlying pathology of many cardiovascular diseases and is characterized by chronic inflammation in the larger arteries. Activation of the NLRP3 inflammasome is one of the drivers of inflammation during atherosclerosis. Purpose Therefore, we aimed to determine the ability of the novel bispecific anti-NLRP3 inflammasome antibody, called InflamAb, to inhibit atherosclerosis. Methods and Results In vitro treatment of bone marrow derived macrophages with 25 ng/mL InflamAb effectively inhibited the IL-1β release induced by NLRP3 inflammasome activation with LPS and Aluminium hydroxide (P<0.05). In addition, InflamAb administration in western-type diet fed Apoe-/- mice significantly reduced circulating IL-1β at 4 hours post inflammasome activation (P<0.05), thereby showing in vivo efficacy of InflamAb. Subsequently, we assessed the effect of InflamAb on both the development of atherosclerosis and on pre-existing plaques. Treatment of western-type diet fed female Apoe-/- mice with 100 µg InflamAb or isotype control antibody (3x per week i.p) significantly inhibited collar-induced atherosclerotic plaque development in the carotid artery from 59±8*10^3 µm^2 in control mice to 36±5*10^3 µm^2 (P<0.05), which coincided with a reduction in relative macrophage (control: 36±2% versus InflamAb: 28±3%, P<0.05) and necrotic core content (control: 16±2% versus InflamAb: 8±1%, P<0.05). InflamAb treatment of male Apoe-/- with pre-existing atherosclerosis did not affect lesion size, but improved plaque stability parameters as illustrated by a reduced relative macrophage (control: 48±2% versus InflamAb: 42±2%, P<0.05) and necrotic core (control: 21±1% versus InflamAb: 18±1%, P<0.05) content. In addition, we observed a trend towards increased collagen levels upon InflamAb treatment (control: 39±2% versus InflamAb: 44±2%, P=0.08). Conclusion To conclude, NLRP3 inflammasome inhibition by the bispecific antibody InflamAb shows promising efficacy in inhibiting atherosclerotic plaque development and destabilization.

Response of sand added with various biopolymer contents under repetitive loading and freeze–thaw cycles

Biopolymers have recently been used as ecofriendly materials for soil improvement in terms of stabilization, compressibility, and engineering parameters. The objective of this study is to assess the effect of biopolymer content in sand mixtures during freeze–thaw repetitive loading cycles. The biopolymers were mixed at weight ratios of 0.0, 0.5, 1.0, 2.0, 5.0, and 10 % (BPC 0.0—BPC 10), and the relative density and degree of saturation were fixed at 60 % and 20 %, respectively. The measurement system was located in an ice chamber for freeze–thaw, and 100 cycles of repetitive loads were applied. The test results showed that the deformation decreased from BPC 0.0, to BPC 1.0 owing to the cementation effect produced by the biopolymer chain and coating. However, the deformation increased from BPC 1.0 to BPC 5.0 because high-viscosity solutions might separate the sand particles, causing a density reduction and generating more deformation by compaction. The relative permittivity varied with respect to BPC and freeze–thaw repetitive loading stages that were affected by unfrozen water content, volume contraction, and water consumption during dehydration. The shear wave velocity gradually increased from BPC 2.0 to BPC 10 because the effect of fines in coarse–fine mixtures, rather than the cementation effect. Therefore, the module containing the sensors used in this study can be used to understand the role of biopolymers as reinforcing materials in railway subgrades.

Immobilized lipase based on SBA-15 adsorption and gel embedding for catalytic synthesis of isoamyl acetate

In this study, Candida rugosa lipase (CRL) was immobilized on the silica carrier SBA-15 by physical adsorption, then mixed with hydrophobically modified sodium alginate and dropped into calcium chloride solution. Finally, the adsorption-embedding immobilized lipase (L-SBA-15-Mgel) was successfully prepared. The conformation of the carrier before and after lipase immobilization were analyzed by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR) and other characterization techniques. The molecular docking and molecular dynamics simulation of CRL and modifier dodecyl glycidyl ether (DGE) ligand were carried out to analyze the potential influence of modifier on enzyme characteristics. The basic enzymatic properties including the activity, stability and reaction kinetic parameters of the immobilized lipase L-SBA-15-Mgel were studied. L-SBA-15-Mgel showed good storage stability and reusability. After 16 days of storage, the activity retention was 47.85%, and there was still 63.20% of the residual activity after seven cycles of reuse. The immobilized lipase was applied to the efficient synthesis of food flavor ester isoamyl acetate. Under the reaction conditions of 50 °C and 200 rpm, the highest yield of isoamyl acetate catalyzed by L-SBA-15-Mgel was 85.19%.

Air–sea interactions in stable atmospheric conditions: lessons from the desert semi-enclosed Gulf of Eilat (Aqaba)

Abstract. Accurately quantifying air–sea heat and gas exchange is crucial for comprehending thermoregulation processes and modeling ocean dynamics; these models incorporate bulk formulae for air–sea exchange derived in unstable atmospheric conditions. Therefore, their applicability in stable atmospheric conditions, such as desert-enclosed basins in the Gulf of Eilat/Aqaba (coral refugium), Red Sea, and Persian Gulf, is unclear. We present 2-year eddy covariance results from the Gulf of Eilat, a natural laboratory for studying air–sea interactions in stable atmospheric conditions, which are directly related to ocean dynamics. The measured mean evaporation, 3.22 m yr−1, approximately double that previously estimated by bulk formulae, exceeds the heat flux provided by radiation. Notably, in arid environments, the wind speed seasonal trend drives maximum evaporation in summer, with a minimum winter rate. The higher evaporation rate appears when elevated wind, particularly in the afternoon, coincides with an increase in vapor pressure difference. The inability of the bulk formulae approach to capture the seasonal (opposite from our measurements) and annual trend of evaporation is linked to errors in quantifying the atmospheric boundary layer stability parameter. Most of the year, there is a net cooling effect of surface water (−79 W m−2), primarily through evaporation. The substantial heat deficit is compensated by the advection of heat via northbound currents from the Red Sea, which we indirectly quantify from energy balance considerations. Cold and dry synoptic-scale winds induce extreme heat loss through air–sea fluxes and are correlated with the destabilization of the water column during winter and initiation of vertical water-column mixing.

Correlating analysis and optimization between hydropower system parameters and multi-frequency oscillation characteristics

This paper aims to study the relationship between multi-frequency oscillation characteristics and parameters of hydro-turbine governing systems (HTGS), as well as improve the system oscillation quantification accuracy and primary frequency regulation performance. Firstly, an HTGS model with multi-frequency oscillation characteristics is established using an actual hydropower system as the object. Then, system oscillation components and the sources of each oscillating link are identified using eigenvalue and correlation analysis. To address the issue that sub-wave interference with dominant oscillation quantization, we innovatively incorporate correlation and frequency indexes into quantification process, and the dominant oscillations of complex HTGS are accurately quantified. On this basis, the detailed partitioning of control parameters is established to obtain the guide graph quickly reflecting the relationship between control parameters and system oscillations. Finally, an integrated optimization strategy with ultra-low frequency oscillation (ULFO) safety and regulation performance constraints is constructed, and control parameters are further optimized under two typical parameter setting methods. The results indicate over 90 % of the stable parameters enable the system to enter ULFO mode, and optimized control parameters utilizing proposed strategy increase regulation speed by 46 % while effectively suppressing ULFO. This paper provides a powerful tool and novel ideas for complex HTGS oscillation analysis and parameter optimization.

Dynamic modeling and parametric instability analysis of internally damped rotating composite shafts in inertial and rotating frames

Parametric resonance may occur when the composite shaft is subjected to periodic axial loads. The phenomenon will lead to the serious destruction of the dynamic system. In this study, we aim to investigate the parametric instability characteristics of rotating composite shafts considering internal damping, and to provide valuable theoretical guidelines for avoiding the occurrence of parametric resonance. The two dynamic models of the composite rotor in the inertial frame and rotating frame are both established using Hamilton's principle. The governing equations of the composite rotor are reduced into a system of Mathieu–Hill equations by means of the Galerkin method. Then Floquet exponent method is employed to conduct parametric stability analysis of the periodic loaded composite rotor. After performing validation of present model and method, numerical results are presented to bring out the influences of reference frame, rotation speed, internal damping and lamination angle on the parametric instability region. The results show that the selection of reference frame does not affect the determination of the size and type of the parametric instability region. However, it is more suitable to use the rotating frame from the perspective of determining the type of the unstable region. The internal damping of composites should not be ignored when analyzing the parametric stability of composite rotors, especially for the high order excitation frequency.

Particulate black carbon mass concentrations and the episodic source identification driven by atmospheric blocking effects in Astana, Kazakhstan

Black carbon (BC) is a component of fine particulate matter (PM2.5) that is a key contributor to adverse human health effects and climate forcing. To date, BC mass concentrations and possible sources in Kazakhstan have not been studied. Thus, understanding the temporal variations of BC for a large developing region with a complex climate is useful. In this study, measurements of fine particulate BC mass concentrations in Astana were made from June 2020 to October 2021 by measuring light absorption of PM2.5 on filters. The mean BC concentration was 2.56 ± 1.29 μg m−3 with maximum and minimum monthly mean BC concentrations being 4.56 ± 2.03 μg m−3 and 1.12 ± 0.42 μg m−3 in January 2021 and June 2020, respectively. Temporal analyses of BC, SO2, PM10, NOx, CO, meteorological and atmospheric stability parameters were performed. Aggregated pollutant ‘episodic loadings’ during the heating and non-heating periods were identified. Their relationships with blocking anticyclones and cyclones were investigated by examining the reversal of meridional gradients at 500 hPa geopotential height (GPH) maps and identifying Omega (Ω) and Rex blocking types. Astana has some of the highest BC concentrations of cities worldwide. Seasonal BC source location identification using Conditional Bivariate Probability Function (CBPF) analysis implicated combined heat and power (CHP) plant emissions as the major BC source in Astana. Significant increases in BC concentrations were observed during the cold season due to numerous sources, generally poorer atmospheric dispersion and blocking events. The Concentration Weighted Trajectory (CWT) analysis results showed that the distribution of the 75th percentile of BC during episodic periods actively controlled by blockings exceeding than the entire measurement period, which may reflect cross-border transport and adjacent countries.

A novel 3D mixed finite element for flexoelectricity in piezoelectric materials

AbstractFlexoelectricity is the intrinsic length‐scale dependent higher‐order electromechanical response of all centro‐ and non‐centro‐symmetric dielectrics, including piezoelectrics. Direct flexoelectricity is defined as the appearance of an electric field due to induced strain gradients. The numerical modeling of flexoelectricity is largely carried out using mixed FE, which has its historical foundations in strain gradient theories. However, existing finite elements are either limited to 2D or have inherited numerical instabilities due to the known saddle‐point structuring. The current work presents a numerically robust three‐dimensional mixed FE for higher‐order electromechanical applications without the use of stabilization or penalty parameters. After its verification, the new finite element is applied to the new problem of truncated semicone torsion, taking into account flexoelectricity in piezoelectric solids, and the original findings are reported. Current research reveals the complex interaction between first‐order (piezoelectricity) and higher‐order (flexoelectricity) electromechanical coupling.

Optimal intersurface stability for unicompartmental femoral component design with two pegs placed on the distal resection surface:5 mm peg length incrementand 10° peg inclination.

The present study aimed to identify the optimal design of the unicompartmental femoral component through parameter analysis and stability evaluation. A finite element (FE) analysis was applied to analyse and adjust the parameter combinations of the anterior tilt angle of the posterior condyle resection surface, the position of the peg, the length of the pegand the inclination angle of the peg, resulting in 10 different FE models. Setting three knee flexion angles of 8.4° (maximum load state during walking), 40° (maximum load state during stair climbing)and 90° (maximum load state during squatting exercise), quantitatively analysing the micromotion values of the bone-prosthesis interfaceand defining a weighted scoring formula to evaluate the stability of different FE models. The validity of the FE analysis was verified using the Digital Image Correlation (DIC) device. The errors between the FE analysis and the DIC test at three flexion angles were 5.6%, 1.7%and 11.1%. The 10 different femoral component design models were measured separately. The FE analysis demonstrated that the design with a 0° anterior tilt angle of the posterior condyle resection surface, both pegs placed on the distal resection surface, lengthened 5 mm pegsand a 10° peg inclination angle provided the best stability. The current study proposed a method for evaluating the stability of the femoral component design. The optimal intersurface stability design of the unicompartmental femoral component was achieved with two pegs placed on the distal resection surface, a 5-mm peg length incrementand a 10° peg inclination. These results might provide a reference for the selection of unicompartmental femoral components in clinical practice and therefore improve the survival rate of future unicompartmental knee arthroplasty. Level III.

Single-Domain Antibody-Gold Nanoparticle Bioconjugates as Immunosensors for the Detection of Hantaviruses.

Hantavirus, a zoonotic pathogen, causes severe syndromes like hemorrhagic fever with renal syndrome (HFRS), sometimes fatal in humans. Considering the importance of detecting the hantavirus antigen, the construction of an immunosensor is essential. The structural and functional characteristics of camelid nanobodies (VHHs) encourage their application in the areas of nanobiotechnology, therapeutics, diagnostics, and basic research. Therefore, this study aimed to standardize stable bioconjugates using gold nanoparticles (AuNPs) and VHHs, in order to develop immunobiosensors for the diagnosis of hantavirus infection. Immobilized metal affinity chromatography (IMAC) was performed to obtain purified recombinant anti-hantavirus nucleocapsid nanobodies (anti-prNΔ85 VHH), while AuNPs were synthesized for bioconjugation. UV-visible spectrophotometry and transmission electron microscopy (TEM) analysis were employed to characterize AuNPs. The bioconjugation stability parameters (VHH-AuNPs), analyzed by spectrophotometry, showed that the ideal pH value and VHH concentration were obtained at 7.4 and 50 μg/mL, respectively, after addition of 1 M NaCl, which induces AuNP aggregation. TEM performed before and after bioconjugation showed uniform, homogeneous, well-dispersed, and spherical AuNPs with an average diameter of ~ 14 ± 0.57 nm. Furthermore, high-resolution images revealed a thin white halo on the surface of the AuNPs, indicating the coating of the AuNPs with protein. A biosensor simulation test (dot blot-like [DB-like]) was performed in stationary phase to verify the binding and detection limits of the recombinant nucleocapsid protein from the Araucária hantavirus strain (prN∆85). Using AuNPs/VHH bioconjugates, a specific interaction was detected between 5 and 10 min of reaction in a dose-dependent manner. It was observed that this test was sensitive enough to detect prNΔ85 at concentrations up to 25 ng/μL. Considering that nanostructured biological systems such as antibodies conjugated with AuNPs are useful tools for the development of chemical and biological sensors, the stability of the bioconjugate indicates proficiency in detecting antigens. The experimental results obtained will be used in a future immunospot assay or lateral flow immunochromatography analysis for hantavirus detection.

Экологическая стабильность и пластичность сортов горчицы сарептской яровой селекции ВНИИМК

Analysis of ecological plasticity and stability must be a base in the development of new genotypes of spring brown mustard. The purpose of the research was a comparative characteristic of spring brown mustard cultivars bred at the V.S. Pustovoit All-Russian Research Institute of Oil Crops by calculated statistic parameters of adaptability, ecological plasticity, stability, stress-resistance, and genetic flexibility in the central zone of the Krasnodar region in 2018–2022. We studied commercial (Nika, Yunona, Gorlinka, Galateya) and promising (VN11/18, VN-27/18, VN-9/18, and VN-25/18) cultivars. The indicators of ecological plasticity and stability were calculated basing on seed yield of spring brown mustard cultivars for five years by a methodology of Eberhart S.A., Rassell W.A. as reworded by Zykin V.А. To calculate a coefficient of a linear regression, we determined environment indexes, which characterized variability of conditions of the cultivar cultivation. The stress-resistance and genetic flexibility were determined by an equation of Rossille A.A., Hamblin J. as presented by Goncharenko А.А. The potential productivity and adaptability were revealed by a methodology of Zhivotkov L.А. The weather conditions in 2020 and 2021 were the most favorable, environmental index had the highest positive meaning and was equal to 1.74 and 1.82 under the highest average yield of brown mustard, which was equal to 1.92 and 1.93 t/ha, respectively. The weather conditions of 2018 and 2022 were less favorable for estimation of brown mustard samples (Ij = -1.71 and -2.00). A comparative analysis of brown mustard cultivars bred at the V.S. Pustovoit All-Russian Research Institute of Oil Crops by parameters of ecological plasticity and stability in the Krasnodar region showed the cultivars Yunona, VN-27/18, and VN-11/18 had the highest plasticity, and Yunona and Galateya demonstrated the highest stability and adaptability to declining of cultivation conditions. Thus, the cultivars Yunona and Galateya were characterized with high yield, plasticity, stability, genetic flexibility, and adaptability. In contrast conditions, the promising cultivar VN-9/18 had high indicators of resistance to stress factors, yield, and adaptability coefficient.

Анализ показателей эффективности подводных буксируемых комплексов по параметрам устойчивости и управляемости

В работе рассмотрен системный подход анализа и синтеза показателей носителя нейтральной плавучести универсального многоцелевого буксируемого геофизического подводного комплекса. В основу системного подхода предложены показатели энергоэффективности, статической и динамической устойчивости. Статическая устойчивость определяется соотношением параметров веса, размерами и геометрией отсеков плавучести лёгкого корпуса. Форма и центровка блоков плавучести лёгкого корпуса с учётом присоединённых масс связаны с величинами скорости буксировки и угла наклона буксирной линии. Достижение статической устойчивости определяется набором альтернатив обтекаемых или необтекаемых форм, а также размеров и соотношение геометрических размеров носителя нейтральной плавучести, обеспечивающих требуемые показатели назначения. Динамическая устойчивость связана с параметрами статической и определяет достижимые параметры качества динамики при буксировке на заданной глубине хода универсального многоцелевого буксируемого комплекса. Выбор и проработка комплекса учитывает изменение параметров плотности воды в зависимости от глубины хода, рыскания и боковой и курсовой устойчивости. Определены соотношения длины, ширины и высоты носителя нейтральной плавучести, а также варианты получения необходимых параметров устройством гидродинамических профилей, крыльев, пластин. Динамическая устойчивость связана с временем стабилизации носителя нейтральной плавучести при изменении высоты хода над донной поверхностью, а также чувствительности на изменение скорости буксировки и изменения длины и угла буксирной линии. Системный анализ, построенный на показателях энергоэффективности, статической и динамической устойчивости в достижимых альтернативах определяет качественную и количественную меру параметров в величинах размерности, веса и запаса плавучести. In the paper considers a systematic approach to the analysis and synthesis of indicators of the neutral buoyancy carrier of a universal multi-purpose towed geophysical underwater complex. The indicators of energy efficiency, static and dynamic stability are proposed as the basis of the systematic approach. Static stability is determined by the ratio of weight parameters, dimensions and geometry of the buoyancy compartments of the lightweight hull. The shape and alignment of the buoyancy blocks of the light hull, taking into account the attached masses, are related to the values of the towing speed and the angle of inclination of the tow line. The achievement of static stability is determined by a set of alternatives to streamlined or non-streamlined shapes, as well as the dimensions and ratio of geometric dimensions of the neutral buoyancy carrier, which provide the required destination indicators. Dynamic stability is related to the parameters of static stability and determines the achievable parameters of the quality of dynamics when towing at a given stroke depth of a universal multi-purpose towed complex. The selection and development of the complex takes into account the change in water density parameters depending on the depth of travel, yaw and lateral and directional stability. The ratios of the length, width and height of the neutral buoyancy carrier are determined, as well as options for obtaining the necessary parameters by the device of hydrodynamic profiles, wings, plates. Dynamic stability is related to the stabilization time of the neutral buoyancy carrier when the stroke height above the bottom surface changes, as well as sensitivity to changes in towing speed and changes in the length and angle of the tow line. A system analysis based on indicators of energy efficiency, static and dynamic stability in achievable alternatives determines the qualitative and quantitative measure of parameters in terms of dimension, weight and buoyancy reserve.

Exploring Resistant Sources of Chickpea against Fusarium oxysporum f. sp. ciceris in Dryland Areas

Fusarium wilt is a fungal disease that has a significant impact on chickpeas worldwide. This study examined the response of 58 chickpea genotypes to Fusarium wilt. The experiment was conducted over two growing seasons at the Sararoud and Maragheh research stations at the Drylands Agricultural Research Institute of Iran. Genotype resistance was screened through wilt incidence records and nonparametric stability statistic evaluation. The identified resistant genotypes were then evaluated in the greenhouse for their response to four isolates of Fusarium oxysporum f. sp. ciceris (races 1/BC, 2, 4, and 6). Out of 58 genotypes, 32 exhibited moderate resistance, while 24 showed strong resistance abilities. Under warmer conditions, disease severity was higher, with scores at the Sararoud location being higher than those at the Maragheh location. Of the total genotypes across all locations and years, 41.4% were resistant, 55.17% were moderately resistant, 1.72% were susceptible, and 1.72% were highly susceptible. The nonparametric stability measures S(1), S(2), and S(3) identified FLIP 05-42C and FLIP 05-43C as stable and resistant genotypes. The study found that Azad/Hashem K3 was stable based on the non-parametric stability measure S(6). Other resistant genotypes were identified using stability parameters NP(1), NP(3), and NP(4), while FLIP 05-104C was identified by NP(2). The genotypes selected by nonparametric stability parameters showed resistance against at least two Fusarium oxysporum f. sp. ciceris races. The screening method and nonparametric stability statistics used in this study were effective in identifying sources of resistance to Fusarium oxysporum f. sp. ciceris.

Impact of left bundle branch area pacing on right cardiac chambers dimensions and function. a medium term single center echocardiographic study

Abstract Introduction Left bundle branch area pacing (LBBAP) has become, in the last years, the preferred method for physiological pacing due to a wider target area, optimal pacing and sensing thresholds, and stable parameters over time. LBBAP ensures rapid and synchronous left ventricular (LV) activation through the left-sided conduction system. On the other hand, there is little data on right ventricular (RV) activation in LBBAP. The purpose of this study was to evaluate the impact of LBBAP on the right heart anatomy and function over a mid-term follow-up period. Material and methods All consecutive patients with successful LBBAP for bradyarrhythmic indications between February 2021 and July 2022 at our institution were eligible for this study. Left bundle branch capture was defined as a paced QRS complex of right bundle branch block morphology, and proof of transition from non-selective to selective capture with differential pacing maneuvers. To avoid confounders, patients with LV ejection fraction below 40% and with severe valvular disease were excluded. In the end, 57 patients were prospectively evaluated. Patient and procedural characteristics were recorded at baseline and follow-up. Also, right atrial (RA) volume, RV basal diameter, tricuspid annulus peak systolic elevation (TAPSE), RV S` wave (RVS`W), and tricuspid regurgitation (TR) were evaluated before the procedure and at the end of the follow-up period. Results The mean age of the patients was 68.9± 10 years, and 70% were males. 29.8% had a baseline right bundle branch block, and 22.8% had a left bundle branch block morphology. The baseline LV ejection fraction was 54.3 ± 9.9 %. The paced QRS duration was similar to the baseline values (128.5 ± 16.3 vs. 134.4 ± 30.4 msec, p=0.119). The pacing and sensing thresholds were 0.7 ± 0.3 V at 0.4 ms pulse duration and 9.7 ± 4.2 mV, respectively. The mean LV activation time (measured as the R wave peak time in V6) was 80.9 ± 12 msec, and the mean RV activation time (measured as the difference between QRS duration and LV activation time) was 51.9 ± 24.2 msec. The patients were followed over a mean period of 591.2 ± 150.3 days. There were no complications over the follow-up period that led to pacing interruption. The follow-up pacing (0.6 ± 0.2 V, p=0.003) and sensing (11.7 ± 6 mV, p= 0.023) thresholds showed significant improvement compared to the procedural values. The right heart echocardiographic evaluation showed non-statistically significant changes between the follow-up and the baseline values for RA volumes (57.9 ± 33.7 vs. 51.5 ± 28.4 ml, p=0.122), RV basal diameter (32.8 ± 5.4 vs. 31.8 ± 6.4 mm, p=0.31), RVS`W (12.8 ± 3.2 vs. 12.85 ± 2.7 cm/sec, p=0.933), and TR (1.8±0.8 vs. 2±1, p=0.07). On the other hand, there was a significant improvement in the TAPSE (22.2±4.3 vs. 20.7±3.6 mm, p=0.021). Conclusions LBBAP was associated with preserved dimensions and function of the right cardiac chambers over a medium-term follow-up period.

Feasibility of left bundle branch area defibrillator implantation using three-dimensional delivery systems and traditional high voltage leads

Abstract Background Left bundle branch area (LBBA) pacing is an innovative cardiac pacing technique that provides physiological stimulation, which is useful in patients affected by atrioventricular block (preventing pacing-induced cardiomyopathy), and could be an alternative strategy to traditional cardiac resynchronization therapy. Recently, Huybrechts el al. have reported a proof-of-concept study concerning left bundle branch area defibrillator (LBBAD) implantation, evaluating the feasibility of positioning a standard high-voltage (HV) lead by manually pre-shaped delivery systems to achieve LBBAD. No follow-up data were available because the leads were moved to standard positions after testing. Purpose This study aimed to assess the safety and feasibility of definitively implanting a traditional HV lead, using novel three-dimensional delivery systems, to stimulate the LBBA and the lead performance in 1-month follow-up. Methods This is a single-center, non-randomized, prospective study. The study population consisted of consecutive patients referred for an ICD implantation between September and October 2023. LBBAD was attempted by exploiting three-dimensional delivery systems to reach the target transseptal location. After positioning an active fixation HV lead in the LBBA, acute pacing measurements were collected. Defibrillation testing was performed using either patient-tailored (DeFT Response) or fixed-tilt waveform. Echocardiographic evaluation using speckle tracking was performed after implantation. A short-term follow-up was planned in order to verify the stability of electrical parameters in one month. Results LBBAD was performed in 9 consecutive patients (mean age 69±11 years, 56% male). The mean time to implant the HV lead was 20 minutes. The HV lead was successfully implanted in 100% of patients, reaching LBBA in 6 (67%) patients at the first attempt and in 3 (33%) at the second attempt. LBBA pacing exhibited a mean QRS duration and V6 R-wave peak time of 128±9 ms and 64±12 ms. Acute LBBA pacing threshold, R-wave amplitudes, and pacing/shock impedances were 0.88±0.22 V at 0.5 ms, 8.4±2.8 mV, and 637±210 Ω/ 75±20 Ω. The defibrillation test (78% patient-tailored and 22% fixed-tilt waveform) was successful in 6 (75%) of patients at the first shock (~22J) and in 2 (25%) at the second shock (~33J)(test aborted in 1 patient due to respiratory issues during sedation). The mean peak strain dispersion of 31.7ms confirmed global synchrony during pacing. The electrical measurements remained stable, and no lead-related complications were observed at 1-month follow-up. Conclusion We performed for the first time ever LBBAD definitive implantation. This study proves the feasibility and safety of using three-dimensional delivery tools for LBBAD procedures and shows optimal results at the implant for up to one month. Nevertheless, a larger and long-term evaluation is needed to evaluate the performance of LBBAD implants.

Permanent epicardial pacing : a first line strategy in children

Abstract Background Permanent cardiac pacing in paediatric patients remains a challenge. According to the European Paediatric and Congenital Society (AEPC) recommendations, below 20 kg epicardial implantation is preferred, while above 20 kg endocardial implantation is given priority unless specific contraindication. In the literature, a weight at 15 kg is also found to be the minimal weight above which an endovascular implantation is considered. However, endovascular systems have been reported to be associated with a high risk of complications. Recent improvements in epicardial leads technology have significantly improved pacing thresholds (1-3), battery life and reduced the risk of re-intervention for epicardial lead dysfunction (4,5). Purpose The aim of the study is to evaluate the long-term results and efficacy of epicardial pacing in children and to investigate risk factors for epicardial lead dysfunction. Method We performed a retrospective, single-centre analysis of consecutive patients aged ˂18 years implanted with an epicardial PM between 2004 and 2020. The data collection included initial pacing parameters, at 1 month, 1 year, 2 years, and at last follow-up, as well as occurrence of early and late complications. Results A total of 101 patients (93 atrial and 131 ventricular epicardial) were analysed. The mean follow-up time was 6.2 years (range 2 days to 16.9 years). Median age at implantation was 4.2 years (IQ 0.3-8.8 years), median weight was 15.2 kg (IQ 5.2-28.0 kg). Congenital heart disease (CHD) was recorded in 59,4% of patients. Reasons for implantation were postoperative complete atrioventricular block (AVB) (40.6%), congenital AVB (37.6%), sinus dysfunction (7.9%), complete AVB with heart disease without surgery (7.9%), others (4%). Four patients had a system infection resulting in device extraction and reimplantation. The mortality rate was 15.8%, but no deaths was directly related to PM implantation or dysfunction. Detection values, impedances were stable over time, and the and average pacing thresholds remained ˂0,98±0,81 volt in the atrium and ˂ 1.57±0,89 volt in the ventricle. Lead survival was 96,7%, 90,7%, 82,3%, 74,5% at 1, 5, 8 and 10 years. The presence of CHD, weight ˂15kg, dual chamber implantation, implantation for postoperative BAV were not significant risk factors for lead dysfunction. In the group of patients implanted above 15kg the presence of a CHD significantly increased the risk of lead dysfunction (p=0.037) and all-cause reimplantation (p=0.010). In the group implanted above 15kg without any cardiopathy, the survival rate without lead dysfunction at 5 and 10 years was 100% and 90.9% respectively. Conclusion Epicardial pacing in children with steroid-eluting leads shows good long-term results with stable pacing parameters and good survival from lead dysfunction. For children implanted at a weight above 15 kg and without cardiopathy results with epicardial stimulation were excellent.Epicardial lead survival

Subnormothermic Oxygenated Machine Perfusion (24 h) in DCD Kidney Transplantation.

Ex vivo kidney perfusion is an evolving platform that demonstrates promise in preserving and rehabilitating the kidney grafts. Despite this, there is little consensus on the optimal perfusion conditions. Hypothermic perfusion offers limited functional assessment, whereas normothermic perfusion requires a more complex mechanical system and perfusate. Subnormothermic machine perfusion (SNMP) has the potential to combine the advantages of both approaches but has undergone limited investigation. Therefore, the present study sought to determine the suitability of SNMP for extended kidney preservation. SNMP at 22-25 °C was performed on a portable device for 24 h with porcine kidneys. Graft assessment included measurement of mechanical parameters and biochemical analysis of the perfusate using point-of-care tests. To investigate the viability of kidneys preserved by SNMP, porcine kidney autotransplants were performed in a donation after circulatory death (DCD) model. SNMP was also compared with static cold storage (SCS). Finally, follow-up experiments were conducted in a subset of human kidneys to test the translational significance of findings in porcine kidneys. In the perfusion-only cohort, porcine kidneys all displayed successful perfusion for 24 h by SNMP, evidenced by stable mechanical parameters and biological markers of graft function. Furthermore, in the transplant cohort, DCD grafts with 30 min of warm ischemic injury demonstrated superior posttransplant graft function when preserved by SNMP in comparison with SCS. Finally, human kidneys that underwent 24-h perfusion exhibited stable functional and biological parameters consistent with observations in porcine organs. These observations demonstrate the suitability and cross-species generalizability of subnormothermic machine perfusion to maintain stable kidney perfusion and provide foundational evidence for improved posttransplant graft function of DCD kidneys after SNMP compared with SCS.