Loss Of Capacity Research Articles

Reversing metabolic reprogramming by CPT1 inhibition with etomoxir promotes cardiomyocyte proliferation and heart regeneration via DUSP1 ADP-ribosylation-mediated p38 MAPK phosphorylation

The neonatal mammalian heart has a remarkable regenerative capacity, while the adult heart has difficulty to regenerate. A metabolic reprogramming from glycolysis to fatty acid oxidation occurs along with the loss of cardiomyocyte proliferative capacity shortly after birth. In this study, we sought to determine if and how metabolic reprogramming regulates cardiomyocyte proliferation. Reversing metabolic reprogramming by carnitine palmitoyltransferase 1 (CPT1) inhibition, using cardiac-specific Cpt1a and Cpt1b knockout mice promoted cardiomyocyte proliferation and improved cardiac function post-myocardial infarction. The inhibition of CPT1 is of pharmacological significance because those protective effects were replicated by etomoxir, a CPT1 inhibitor. CPT1 inhibition, by decreasing poly(ADP-ribose) polymerase 1 expression, reduced ADP-ribosylation of dual-specificity phosphatase 1 in cardiomyocytes, leading to decreased p38 MAPK phosphorylation, and stimulation of cardiomyocyte proliferation. Our present study indicates that reversing metabolic reprogramming is an effective strategy to stimulate adult cardiomyocyte proliferation. CPT1 is a potential therapeutic target for promoting heart regeneration and myocardial infarction treatment.

Enhancing fire performance of glulam beams through thermal treatment, inorganic impregnation, and densification techniques

The present research investigates a novel, environmentally benign modification method for improving the fire performance of Chinese fir that grows quickly and at low density. This wood is known for its susceptibility to burning and rapid loss of load-bearing capacity in fires. After thermal treatment, inorganic impregnation, and densification, Chinese fir was utilized as the fire-exposure surface for glulam beams. Three sides of full-size members were subjected to fire tests lasting 60 and 90 minutes. Considering the gluelines' thermal conductivity, the improved glulam beams' fire performance was thoroughly evaluated using the finite element program ABAQUS. The study found that the composite modification approach enhanced the weight percentage and mass density of the wood laminates by 32.53 % and 67.87 %, respectively. After 60 min of fire exposure, the charring rates on the exposed surface of the members with the modified laminates were 13.5 % and 27.8 % lower than those of standard glulam beams, indicating a considerable improvement in fire resistance. Greater post-fire residual cross-sectional area and improved fire resistance performance were correlated with an increase in the quantity of modified laminates. The composite modified glulam beams showed a noticeable temperature gradient, which was explained by higher density and specific heat capacity and consequently improved overall fire resistance, according to finite element analysis. The corner effect on the glulam beam cross-section became more evident with prolonged heating, while the gluelines had minimal impact on overall heat transfer.

Effects of adding mealworm (Tenebrio molitor L.) as a replacement for fish meal to broiler chicken diet on performance, carcass parameters, meat quality and nutrient digestibility.

The objective of the study was to investigate how substituting fish meal (FM) with mealworm larval (Tenebrio molitor L.) meal (TM) in the diet affects the growth performance, meat quality, nutrient digestibility, and carcass of broiler chicks. A total of one hundred chicks were divided into five groups, each containing twenty birds. The fish meal was replaced with mealworm meal at different levels of 25% (TM25), 50% (TM50), 75% (TM75), and 100% (TM100) in the diets. At the end of the study, replacing different levels the fish meal with mealworms linearly suppressed nutrient digestion, growth, carcass parameters, and water holding capacity and cooking loss. However, the best energy efficiency ratios were obtained in the TM100 group. Consequently, it was concluded that replacement of FM with mealworm up to 25% had no adverse effect on growth performance, carcass parameters, meat quality and nutrient utilization efficiency of broiler chickens.

NiCo alloy-decorated nitrogen-doped carbon double-shelled hollow polyhedrons with abundant catalytic active sites to accelerate lithium polysulfides conversion

Lithium-sulfur (Li-S) batteries have received significant attention due to their high theoretical energy density. However, the inherent poor conductivity of S and lithium sulfide (Li2S), coupled with the detrimental shuttle effect induced by lithium polysulfides (LiPSs), impedes their commercialization. In this study, we develop NiCo alloy-decorated nitrogen-doped carbon double-shelled hollow polyhedrons (NC/NiCo DSHPs) as highly efficient catalysts for Li-S batteries. The distribution of NiCo alloy on both the inner and outer shells provides abundant catalytic active sites, effectively adsorbing LiPSs, mitigating the shuttle effect, and promoting the conversion between LiPSs and Li2S, even at high sulfur loadings. This results in enhanced redox kinetics within the Li-S system. Moreover, the highly conductive carbon material framework, enriched with carbon nanotubes and graphitic carbon layers, can greatly promote the efficient electron transportation. Additionally, the improved ion diffusion rates benefiting from the hollow structure can also be realized. By harnessing these synergistic effects, Li-S batteries incorporating the double-shelled NC/NiCo DSHP catalysts achieved a high specific capacity of 1310 mAh/g at 0.2C and a superior rate performance of 621 mAh/g at 4C. Furthermore, excellent cycling performance with ultralow capacity fading rate of only 0.045 % per cycle after 800 cycles at 1C was achieved. When sulfur loading reaches 6 mg cm−2, a high capacity of 4.6 mAh cm−2 at 0.1C after 100 cycles further validates the practical potential of this design. This study presents an innovative approach to alloy catalyst design, offering valuable insights for future research of Li-S batteries.

Polypyrrole as the MOFs/polymer interfacial binder applied in mixed matrix porous separator for high temperature safe lithium-ion batteries

Uniform distribution of two-dimensional (2D) metal organic frameworks (MOFs) in polymer composites is crucial for fabricating mixed matrix porous separators (MMPS) for metal-ion (M+) batteries (MIBs). However, effectively incorporating 2D MOFs into mechanically robust and highly transportive MMPS, without agglomeration and leaching, has been challenging. Herein, we report the post-polymerization of polypyrrole (PPy) on 2D Cu-MOFs nanosheets, and their uniform distribution in the poly-(arylene ether benzimidazole) (OPBI) to prepare highly porous and mass transportive MMPS using non-solvent induced phase separation (NIPS) method for lithium ion (Li+) batteries (LIBs) applications. The polymerization of PPy not only improved the dispersibility of the Cu-MOFs nanosheets, but also acted as an interfacial binder, ensuring compatibility between the MOFs and OPBI chains. The PPy@Cu-MOFs nanosheets increased the pore size and porosity of the OPBI-based MMPS, creating wider and more uniform cross-sectional channels, thereby enhancing Li+ flux between the anode and cathode during battery charge/discharge cycles. The thermally stable, electrolyte-affinitive, and lithophilic PPy@Cu-MOFs/OPBI MMPS, when assembled in LIBs, achieved a discharge capacity of 150.2 mAh· g−1 with sustained performance over 200 cycles, showing no capacity fading even at elevated temperature. This work provides new insights into polymerizing conjugated polymer on 2D-MOFs nanosheets for improved dispersibility and uniform distribution, enabling the design of high-performance, mass transportive MMPS for safe LIBs application to meet current green energy demands.

A dual-port MIMO antenna system for 5G and Wi-Fi 6E communications using a parasitic element

The increasing demand for high-speed, reliable wireless communication necessitates innovative antenna designs that can efficiently support emerging technologies such as 5G and Wi-Fi 6E. Traditional antenna solutions often struggle to meet the compactness, isolation, and efficiency requirements posed by these advanced systems. This research addresses these challenges by introducing a compact dual-hook multiple input multiple output (MIMO) antenna specifically tailored for 5G and Wi-Fi 6E applications. The proposed antenna offers dual-band operation in a small size with high isolation at both resonance frequencies (3.6 GHz and 7.1 GHz). The novel design has a simple and low-profile structure and can be easily integrated into practical applications. It reduces the cost and complexity of the system. The MIMO technology has a good reflection coefficient, a good efficiency and a maximum gain of 3.85 dB. To enhance the effeciency of this structure, parasitic element and defective ground structure (DGS) are combined. The twin-hook radiators are printed symmetrically on the top layer of low-cost FR-4 substrate with a small size of 19 × 36 mm2 (0.23 λ0 × 0.45 λ0, with λ0 is the guided wavelength at the lowest operating frequency). In addition, the DGS is formed by cutting two symmetrical slots into the semi-ground plane to provide better impedance matching at both resonant frequencies. Based on the simulation findings, the -10dB return loss bandwidth of the proposed structure reaches approximately 14,08% and 10,21% for 3.6GHz and 7.1GHz, respectfully. On the other hand, high isolation is obtained, reaching over -21 dB in the low frequency band and -29 dB in the high frequency band. Also, for verification of MIMO system characteristics, diversity gain (DG), envelope correlation coefficient (ECC), total active reflection coefficient (TARC) and channel capacity loss (CCL) are analysed and used to investigate the proposed MIMO antenna diversity performance.

Enhanced cyclability of O3-NaNi0.33Fe0.31Mn0.36O2 by Mg and Cu synergistic doping with strengthened Mn[sbnd]O bonds

Among some practical O3-type layered oxide cathodes, NaNi1/3Fe1/3Mn1/3O2 (NFM) features a high specific capacity and moderate cyclability. However, sluggish Na+ transfer kinetics, low structural stability, and rapid capacity loss during long-term cycling, are still posing a challenge to commercial applications of this material. In this work, we propose a Mg and Cu co-doped O3-type NaMg0.02Cu0.02Ni0.33Fe0.27Mn0.36O2 (MC-NFM) with a stable structure and good cycling stability. It was found that the MnO bonds in MC-NFM are obviously reinforced by synergistic doping with small amounts of Mg and Cu, leading to enhanced structural robustness, decreased Na+ migration barrier, and delayed O3-P3 phase transition. As a result, longer cycle life and enhanced rate performance are achieved. MC-NFM can yield a specific capacity of 142.1 mAh g−1 at 0.1C and 116.0 mAh g−1 at 5C, and maintain 83.6 % of its initial capacity after 400 cycles at 1C. This work provides a promising design of O3-type cathode for sodium-ion batteries.

A Multifunctional Secondary Based on Heterogeneous Co-MnO@NC for Depth-Induced Deposition and Conversion of Polysulfides in Li─S Batteries.

The conductive carbon-based interlayer, as the secondary current collector in the self-dissolving battery system, can effectively capture escaping cathode active materials, inducing deep release of remaining capacity. In the multi-step reactions of Li─S batteries, the environmental tolerance of the conductive carbon-based interlayer to polysulfides determines the inhibition of shuttle effects. Here, a modified metal-organic framework (Mn-ZIF67) is utilized to obtain nitrogen-doped carbon-coated heterogeneous Co-MnO (Co-MnO@NC) with dual catalytic center for the functional interlayer materials. The synergistic coupling mechanism of NC and Co-MnO achieves rapid deposition and conversion of free polysulfide and fragmented active sulfur on the secondary current collector, reducing capacity loss in the cathode. The Li─S battery with Co-MnO@NC/PP separator maintains an initial capacity of 1050mAhg-1 (3C) and excellent cycle stability (0.056% capacity decay rate). Under extreme testing conditions (S load = 5.82mgcm-2, E/S=9.1µLmg-1), a reversible capacity of 501.36mAhg-1 is observed after 200 cycles at 0.2C, showing good further practical reliability. This work demonstrates the advancement application of Co-MnO@NC bimetallic heterojunctions catalysts in the secondary current collector for high-performance Li─S batteries, thereby providing guidance for the development of interlayer in various dissolution systems.

Mn and Ti Co-doping of LiNiO2 to Improve Performance

LiNiO2 (LNO) has high capacity but suffers from structural instability and capacity fade, which limits its practical use in lithium-ion batteries. This study proposes co-doping LNO with Mn and Ti (MnTi25) as a strategy to overcome these issues. MnTi25 was thoroughly characterized, revealing improved structural stability and significantly reduced cation mixing compared to pristine LNO. The half-cell performance of MnTi25 is noteworthy, exhibiting a capacity similar to the established 4% Mn-substituted ZoomWeMn4 standard, demonstrating efficient Li-ion extraction and insertion. Additionally, full-cell testing against a graphite anode shows that MnTi25 delivers a capacity almost identical to a commercial LNO-based material. This promising achievement highlights the effectiveness of co-doping in addressing LNO's limitations while preserving its high-capacity potential. This study demonstrates that MnTi25 can be a promising cathode material for high-performance lithium-ion batteries by tailoring the material's structure through co-doping.

Unveiling electrochemical insights of lithium manganese oxide cathodes from manganese ore for enhanced lithium-ion battery performance

Implementing manganese-based electrode materials in lithium-ion batteries (LIBs) faces several challenges due to the low grade of manganese ore, which necessitates multiple purification and transformation steps before acquiring battery-grade electrode materials, increasing costs. At present, most Lithium Manganese Oxide (LMO) materials are synthesized using electrolytic manganese dioxide, and the development of new processes, such as hydrometallurgical processes is important for achieving a cost-effective synthesis of LMO materials. In this work, we develop a full synthesis process of LMO materials from manganese ore, through acid leaching, forming manganese sulfate monohydrate (MnSO4·H2O), an optimized thermal decomposition (at 900, 950 or 1000 °C) producing different Mn3O4 materials and a solid-state reaction, achieving the synthesis of LMO. The latter was used as a cathode material for LIB exhibiting a specific capacity comparable to the state-of-the-art LMO cathode with a remarkable cycling stability of 800 cycles with <20 % in capacity loss. These performances were attributed to the excellent redox reversibility of the LMO cathode, characterized by voltammetry and in operando and in situ characterization by Raman and XRD.

Liquid nitrogen temperature to 700 K Bi3+ thermoluminescence: Toward wide-temperature-range light dosimeters for versatile anti-counterfeiting, information storage, and x-ray imaging

Discovering light dosimeters that can function effectively from liquid nitrogen temperature to 700 K presents significant challenges. Such dosimeters facilitate a range of cutting-edge applications, including anti-counterfeiting measures at low temperature for cryo-preservation. To facilitate such discovery, stacked vacuum referred binding energy diagrams for the LiYGeO4 cluster of crystals have been first constructed. They offer a robust method for controlling both electron and hole trapping depth in the LiYGeO4 cluster of crystals. Wide temperature shifting of Bi2+ and Eu2+ thermoluminescence (TL) glow bands emerges from 200 to 500 K for LiYxLu1-xGeO4:0.01Bi3+ and LiYxLu1-xGeO4:0.01Bi3+, 0.001Eu3+, by changing x, facilitating conduction band tailoring. Wide temperature shifting of Bi4+ TL glow bands emerges from 300 to 700 K for LiYGezSi1-zO4:0.01Bi3+, by tuning z, facilitating valence band tailoring. TL glow band peaks near 135, 185, 232, and 311 K emerge in LiyNa1-yYGeO4: 0.001Bi3+. Particularly, the discovered Bi3+ or/and lanthanide modified LiYGeO4 cluster of crystals exhibit superior charge carrier storage capacity and minimal TL fading properties. For instance, the ratio of TL intensity of the optimized LiYGe0.75Si0.25O4:0.001Bi3+ to that of industrial BaFBr(I):Eu2+ is as high as ∼4. Interestingly, imaging of intense optically driven Bi3+ ultraviolet-A (UVA) luminescence has been validated in 254 nm energized LiY0.25Lu0.75GeO4:0.01Bi3+ with a 100 lux white LED illumination. Together with ZnS:Mn2+, LiTaO3:Bi3+, Sm3+, and Cs2ZrCl6:Sb3+ perovskites, the realization of wide range liquid nitrogen temperature to 700 K Bi3+ thermoluminescence in Bi3+ or/and lanthanide modified LiYGeO4 cluster of crystals with superior charge carrier storage capacity offers promising use for versatile anti-counterfeiting, information storage, and delayed x-ray imaging purposes.

An Adaptive Combined Method for Lithium‐Ion Battery State of Charge Estimation Using Long Short‐Term Memory Network and Unscented Kalman Filter Considering Battery Aging

AbstractThe accurate estimation of battery state of charge (SOC) enables the reliable and safe operation of lithium‐ion batteries. Data‐driven SOC estimation is considered an emerging and effective solution. However, existing data‐driven SOC estimation methods typically involve direct estimation and lack effective feedback correction. Moreover, battery degradation poses additional challenges to accurate SOC estimation. Therefore, this study proposes an adaptive combined method for battery SOC estimation based on a long short‐term memory (LSTM) network and unscented Kalman filter (UKF) algorithm considering battery aging status. First, an LSTM model is constructed to characterize the battery's dynamic performance instead of traditional battery models. Then, the UKF algorithm is employed to perform SOC estimation through the feedback of terminal voltage prediction. To enhance estimation accuracy under different aging statuses, a proportional‐integral‐derivative controller is employed to correct the capacity fading during the SOC estimation process. Validation results indicate that the terminal voltage prediction model demonstrates exceptional robustness against interference from current and voltage noise. Compared to the traditional estimation method combining the deep learning model and Kalman filter algorithm, the proposed method demonstrates superior estimation accuracy under various complex operating conditions. Furthermore, the proposed method outperforms the traditional method in estimation performance during battery aging.

The Analysis of the Thermal Processes Occurring in the Contacts of Vacuum Switches During the Conduction of Short-Circuit Currents

This article presents the results of research on the thermal state of vacuum switch contacts during the conduction of short-circuit currents. This state is directly related to the value of the flowing current and the operating conditions of the switch. These conditions are mildest in the case of the conduction of operating currents through closed contacts. The situation worsens significantly when short-circuit currents are conducted, and the greatest destructive effects occur during commutation processes. Exceeding a certain level of contact destruction usually leads to the loss of the switching capacity of the switch. In vacuum switches, tracking the thermal state of the contacts is particularly difficult due to the inaccessibility of transducers or measurement sensors inside the chamber. In such a case, simulation studies verified by experimental results are important. This paper presents the results of such studies, directed at their practical implementation in the design and operation of vacuum switches. Simulation studies were conducted to analyze the thermal processes occurring in the contacts of vacuum switches during the conduction of short-circuit currents. Special attention was paid to the influence of contact parameters on the thermal processes occurring during the conduction of short-circuit currents. In addition to simulations, experimental studies were carried out to verify the simulation results. Ultimately, the research results presented are intended to provide practical knowledge of the design and operation of vacuum switches, particularly with regard to the contact heating processes during the conduction of short-circuit currents.

Investigating the Response Mechanism of Vertical Concrete Structures to Alternating Horizontal and Lateral Loads

The improper performance of columns in concrete buildings designed and built in the past years has caused concern and attention to their vulnerability to collapse. The investigation of the damages caused to the structures after various earthquakes and the research conducted during these years have caused changes in the design practices to achieve ductile behavior in the columns. Most of the efforts have been made in these years to improve the design criteria, but the effect of the axial force or the loss of the axial capacity of the columns in the existing buildings built in the past years is still unknown. Most of these columns have transverse reinforcements with large distances, which provide little lateral resistance for the longitudinal reinforcements and also little confinement for the concrete in seismic loads. Many of these columns are not accepted according to the rules of today's regulations. In these columns, not only determining the shear capacity but also the ability of the column to withstand the axial force after the shearing is of great importance. The failure of such columns is due to shear deformations that lead to shear failure and then axial failure. At first, a comprehensive review is done of the studies of other researchers. In this review, we try to collect the analytical and laboratory studies available in the technical literature. These studies are related to the testing of concrete columns until the time of gravitational collapse and the behavior models of the columns until this limit state. Then, according to the collected information and their analysis, several columns will be designed and built for laboratory study. These columns are designed to represent the condition of columns in old concrete buildings. The comparison between the analytical and laboratory results of the 6 tested column samples shows a good agreement between them. As a result, the proposed method has sufficient accuracy and efficiency to determine the effective stiffness of columns.

Binder-free tin (IV) oxide coated vertically aligned carbon nanotubes as anode for lithium-ion batteries

Despite the tremendous potential of tin oxide (SnO2) as an anode material, irreversible capacity loss due to the sluggish kinetics and structural pulverization as a result of the substantial volume alteration during redox reactions limits its use in lithium-ion batteries. The typical layered design of an electrode consisting of binder and conductive additive can lower the practical capacity of high-capacity electrode materials. We synthesized a binder and conductive additive-free, self-standing core-shell vertically-aligned carbon nanotubes (VACNTs)-SnO2 anode (SnO2-VACNTs) on 3D nickel foam using plasma-enhanced chemical vapor deposition and wet chemical method. The SnO2-VACNTs exhibited excellent cyclability with a specific capacity of 1512 mAh g−1 at 0.1 A g−1 after 100 cycles and 800 mAh g−1 at 1 A g−1 after 200 cycles. The ultra-fine SnO2 particles (<5 nm) shortened the Li+ diffusion paths into the bulk electrode and alleviated the volume alteration by lowering the strains during the redox reactions. Also, proper inter-tube distance between individual SnO2-VACNTs buffered the volume instability and offered better electrolyte accessibility. Direct connection of VACNTs with the current collector ensured an uninterrupted electron conducting path between the current collector and active material, thus offering more efficient charge transportation kinetics at the electrode/electrolyte interfaces.

Pressure‐Induced Capacity Recovery and Performance Enhancements in LTO/NMC‐LCO Batteries

AbstractLithium titanate oxide (LTO) batteries are a promising technology, particularly suitable for high‐power applications, owing to their inherent cyclic stability, fast charging capability, and superior safety. However, substantial gas generation and accelerated aging driven by the cathode remain substantial challenges. This study explores the mitigation of these aging mechanisms through the application of external mechanical compression. Continuous pressure of 0.3 MPa applied to pristine cells during cycling reduces capacity loss by 42% compared to unpressurized cells cycled under identical operating conditions. Applying short‐term pressure to aged cells leads to immediate capacity recovery, reclaiming up to 57% of the lost capacity. Subsequent cycling of these aged cells under continuous pressure demonstrates improved capacity retention. In contrast, intermittently applied transient pressure causes notable capacity fluctuations. This study reveals insights into aging and healing mechanisms influenced by external pressure, benefiting both first‐ and second‐life battery applications. Understanding these mechanisms is vital for enhancing performance and lifetime in battery packs, while the findings also highlight promising opportunities for capacity recovery in reused batteries.

Screening of Cation Exchange Membranes for an Anthraquinone‐Ferrocyanide Flow Battery

AbstractThe disodium salt of 9,10‐anthraquinone‐2,7‐disulphonic acid (2,7‐AQDS) is an interesting platform for developing anthraquinone derivative negolytes for aqueous organic flow batteries. Recently, ammonium sulphate supporting electrolytes have been considered for improved stability and solubility. This work advances the 2,7‐AQDS/ferrocyanide flow battery with an ammonium sulphate supporting electrolyte (pH 5) by studying the suitability of six commercially available cation exchange membranes: E‐620, NR‐212, FS‐930, F‐1075‐PK, F‐1850 and N‐115. Cell cycling under galvanostatic regime plus potential hold was performed to determine coulombic efficiency, energy efficiency and accessible capacity for each membrane as well as capacity fade rate for three selected membranes under extended operation. Cell cycling under galvanostatic control only was carried out to observe transient membrane behavior alongside accessible capacity and apparent capacity fade rate. It was found that the capacity set by the limiting negolyte is consistent with 1.5 electrons per 2,7‐AQDS molecule and that energy efficiency shows a simple direct relationship to membrane thickness, with one exception. Meanwhile, four membranes displayed similar apparent capacity fade rates at this laboratory scale irrespective of their thickness, with capacity loss explained in terms of crossover. The best overall performance was attained by the thinnest membranes, E‐620 and NR‐212.

Dual band four port MIMO antenna with dual circular polarization for Wi-Fi/WiMAX applications

The planar compact four port circularly polarized printed MIMO antenna described in this article is small and intended to support Wi-Fi and WiMAX applications. Suggested four E-shaped monopole elements make up the dual circularly polarized (CP) MIMO antenna that has two left hand CP (LHCP) elements and two right hand CP (RHCP) elements. An I shaped strip is used to join separate ground planes of designed E shaped monopole antenna to have same voltage levels. A good diversity performance is achieved with an envelope correlation coefficient (ECC) of less than 0.15. The 60 mm × 60 mm antenna is designed from FR4 material, which is inexpensive and has a 1.6 mm thickness. Using a high-frequency structure simulator (HFSS), the suggested MIMO antenna is designed and optimized. The measured findings demonstrate the circular polarization, 3-dB axial ratio beamwidth, impedance bandwidth of 2.11 GHz −2.42 GHz and 3.40 GHz-3.51 GHz, adequate axial ratio bandwidth (ARBW) of the suggested MIMO antenna along with high isolation of −17 dB, gain of 3.43 and 2.09 dBic at 2.4 GHz and 3.5 GHz respectively, TARC (Total active reflection coefficient) of less than 0 dB, a CCL (Channel capacity loss) of lesser than 0.4 bits/sec/Hz, and an MEG (Mean effective gain) value of less than 3 dB.

ABOUT THE PROCESS OF ACCUMULATION OF SEDIMENTS IN THE RESERVOIR

The accumulation of sediment and the associated loss of useful reservoir capacity is a serious global problem. The problems of quantitative assessment of sediment deposits and forecasting the form of their location in the reservoir are relevant. The first of these problems has been solved quite well, but the second problem remains practically open.

Prognostic value of left atrial strain in patients with moderate to severe mitral stenosis

Abstract Background Mitral stenosis causes an inflow restriction during diastole and is characterized by an increase in left atrial (LA) pressure with reduced cardiac output. Pressure overload of the LA can lead to atrial fibrosis and remodeling, resulting in a loss of LA reservoir and compliance capacity that can lead to backward load on the pulmonary circulation. To date, there are limited studies evaluating the impact of LA strain on prognosis of mitral stenosis patients. Purpose The aim of this study was to assess the prognostic value of LA strain in patients with moderate to severe mitral stenosis using two-dimensional (2D) strain imaging. Methods This was a single-center retrospective study, 237 patients with moderate or severe mitral stenosis were enrolled from January 2010 to December 2022. Baseline clinical and echocardiographic parameters were collected, LA strain measurements with reference time point at end diastole for reservoir strain (LASr), conduit strain (LAScd) and contraction strain (LASct) were analyzed using TOMTEC software. The endpoint was a composite outcome of all-cause mortality, heart failure hospitalization and valve intervention (percutaneous transvenous mitral commissurotomy and surgical intervention). All the LA parameters were analyzed separately to avoid collinearity. Results A total of 237 patients were included in the study. The patients had a mean age was 66.56 ± 13.61 years-old and were predominantly female (67.9%) with median follow up duration is 4.54 years (IQR 1.44 – 6.44). Mean left ventricular ejection fraction (LVEF) was 56.86 ± 10.51%, mean left atrium volume index (LAVI) was 73.94 ± 55.46 ml/m2, mean for LASr, LAScd and LASct were 11.81 ± 8.89%, -6.19 ± 4.50%, and -5.58 ± 6.05% respectively. LASr with a cut-off &amp;lt; 15.8% was independently associated with the composite outcome of all-cause mortality, heart failure hospitalization and valve intervention on multivariable Cox regression analysis (HR 2.51, 95% CI 1.54 - 4.10, p &amp;lt; 0.001). LAScd, LASct and LA volume index did not demonstrate any significant association with the endpoint. Conclusion LASr was independently associated with all-cause mortality, heart failure hospitalization and valve intervention in patients with moderate to severe mitral stenosis.