Left End Research Articles

Deformation Monitoring and Potential Risk Detection of In-Construction Dams Utilizing SBAS-InSAR Technology—A Case Study on the Datengxia Water Conservancy Hub

Deformation monitoring plays a pivotal role in assessing dam safety. Interferometric Synthetic Aperture Radar (InSAR) has the advantage of obtaining an extensive range of deformation, regardless of weather conditions. The Datengxia Water Conservancy Hub is the largest in-construction dam in China. To effectively assess the in-construction dam safety, the SBAS-InSAR (Small Baseline Subset-InSAR) technique and 86 Sentinel-1 images (from 11 February 2020, to 16 January 2023) have been employed in this study to monitor the deformation over the reservoir and its surrounding areas. The reliability of the SBAS-InSAR monitoring results over the study area was demonstrated by the in situ monitoring results. And the InSAR results show that the central section of the left dam exhibits the most substantial cumulative deformation, attributed to the maximal water pressure. This is closely followed by the left end of the dam, which reflects a similar but smaller deformation. However, the in-construction cofferdam facilities make the right-end section of the left dam more robust, and the deformation is the most stable. Additionally, significant deformation of the auxiliary dam slope has been identified. Moreover, the analysis indicated that the deformation of the four upstream slopes is closely related to the precipitation, which potentially poses a threat to the safety of the Datengxia Dam.

Analysis of Dynamic Wear Characteristics of Joint Contact Friction Pair of Excavators Working Device

The working device of an excavator in construction machinery is prone to damage and wear under ordinary working conditions. Based on a model of an excavator under typical working conditions, the dynamic load-bearing situation of the three main joint friction subsets of the working device is simulated by using the virtual prototype technology; the location of the functional device with high stress is identified based on finite element analysis, and the correctness of the simulation results is verified by designing strain gauges. Based on this, the dynamic contact stress variation law of the contact surface of the end-face friction subsets was explored, and the end-face wear depth was calculated by combining Archard wear theory and finite element wear simulation technology; the specimens were worn on the end-face wear tester, and the surface wear was observed under the scanning electron microscope to summarize the wear mechanism and analyze the element content changes of the worn surface. The results show that the three main joints of the working device produce large dynamic fluctuations and are prone to wear, and the destructive degree is more prominent; the wear process is accompanied by higher temperatures, fatigue wear, and abrasive wear on the wear surface, and the wear depth value of the right end face is significantly larger than that of the left end face. This method has a significant reference value for reliability analysis and optimization improvement when using construction machinery’s main joint friction pairs.

Elastostatics of nonuniform miniaturized beams: Explicit solutions through a nonlocal transfer matrix formulation

A mathematically well-posed nonlocal model is formulated based on the variational approach and the transfer matrix method to investigate the size-dependent elastostatics of nonuniform miniaturized beams. The beams are composed of an arbitrary number of sub-beams with diverse material and geometrical properties, as well as small-scale size dependency. The model adopts a stress-driven nonlocal approach, a well-established framework in the Engineering Science community. The curvature of a sub-beam is defined through an integral convolution, considering the bending moments across all cross-sections of the sub-beam and a kernel function. The governing equations are solved and the deflections are derived in terms of some constants. The formulation uses local and interfacial transfer matrices, incorporating continuity conditions at cross-sections where sub-beams are joined, to define relations between constants in the solution of a generic sub-beam and those of the first sub-beam at the left end. The boundary conditions are then imposed to derive an explicit, closed-form solution for the deflection. The solution significantly simplifies the study of nonuniform beams with multiple sub-beams. The predictions of the model for two limiting cases, namely local nonuniform and nonlocal uniform beams, are in excellent agreement with the available literature data. The flexural behavior of nonuniform miniaturized beams, composed of two to five different sub-beams and subjected to different boundary conditions, is studied. The results are presented and discussed, emphasizing the effects of the material properties, nonlocalities, and lengths of the sub-beams on the deflection. It is demonstrated that the flexural response of nonlocal nonuniform beams is more complex than local counterparts. Unlike the local beams, dividing a nonlocal uniform beam into multiple sub-beams and then reconnecting them changes the overall stiffness of the beam. The study highlights the potential to design nonuniform miniaturized beams with specific configurations to control their flexural response effectively.

Evaluation of Styloid Process Elongation in Madinah, Saudi Arabia: A Retrospective Radiographic Investigation.

This study aimed to identify the prevalence of an elongated styloid process and analyze the presence of its calcification in the Saudi population using panoramic radiographs. The Taibah Outpatient Dental Clinic's OPG radiographs for 962 patients who attended screening clinics between December 2022 and October 2023 were all included in the study. Patients' demographics, such as age, gender, and nationality, as well as radiological data, were included in the following study variables: the presence of an elongated styloid on both sides of a panoramic radiograph, right side styloid length, left side styloid length, right side distal end thickness, and left side distal end thickness. The study evaluated 438 (45.5%) processes found in individuals aged 16-80 years old. The elongated process length ranged from 30.0 to 40.1 mm, and the diameter ranged from 0.81 to 7.79 mm at the origin to 0.56-3.79 mm at the end. There was no statistically significant difference in process length across genders or age groups. The diameters of the styloid bones on the left side vary significantly across genders at the start and completion of the process. The prevalence of elongated styloids in the studied population was 4.26%. The radiological evaluation of the styloid process is a crucial stage in dental surgery planning.

Three-dimensional modification for vibration reduction and uniform load distribution focused on unique transmission characteristics of herringbone gear pairs

Herringbone gear pairs are widely utilized in high-power transmission devices. However, the current modification methods for these gear pairs are predominantly based on techniques designed for other types of gear pairs, which may not fully capture the specific transmission characteristics of herringbone gear pairs. Consequently, a novel three-dimensional modification approach focused on transmission characteristics of herringbone gear pairs is proposed to address vibration reduction and uniform load distribution. The relationship between gear modification and transmission characteristics is established, enabling the determination of optimal profile and axial modification parameters by integrating the targets of vibration reduction and uniform load distribution. Experimental validation is conducted to verify the models describing the transmission characteristics of herringbone gear pairs. Furthermore, an illustrative example is provided to demonstrate the optimization design methodology for three-dimensional modification. The results exhibit a significant reduction in vibrations in both the circumferential and axial directions, by approximately 11-fold and 1050-fold, respectively, while substantially improving the issue of partial load. In addition, the comparative results also indicate that it is difficult to achieve the goal of vibration reduction and uniform load distribution by using the same modification method for the tooth at the left and right ends of the herringbone gear.

Effect of vent area on vented ammonia-hydrogen-air deflagrations in a 1-m-long duct

Although ammonia-hydrogen blended fuel has become a research hotspot, it is essential to recognize that adding hydrogen to ammonia increases the potential explosion hazard before considering the development of ammonia-hydrogen fuel. In this study, the effect of vent area on vented deflagrations of ammonia-hydrogen-air mixtures is investigated in a 1-m-long horizontal rectangular duct with a right end opening at an initial temperature of 293 K and an initial pressure of 101 kPa. A dimensionless vent coefficient Kv is used to define the vent area in this work to clarify the evolution of flame structures and overpressure inside and outside the duct. For a specific Kv, the amplitude of the maximum internal explosion overpressure (Pmax) monitored at the left end of the duct (LE) has a greater difference compared with other pressure monitoring points. The maximum amplitude of Pmax is always reached at the LE for Kv ≤ 3.2, while the difference in the maximum amplitude of Pmax between different monitoring points decreased significantly for Kv > 3.2. With the increasing of Kv from 2.2 to 20.1, Pmax obtained at the right end of the duct (RE) and the center of the duct increases monotonously, but Pmax monitored at the LE shows a non-monotonic increasing trend. A spike structure of penetrating flame bubbles resulting from negative pressure balance is only observed inside the duct for Kv ≤ 5.6. Two types of oscillations (Helmholtz and Acoustic oscillations) can be distinguished in some tests, and only acoustic oscillations of overpressure can be clearly found in tests with Kv > 7.8. With the increasing of Kv from 2.2 to 20.1, the shape of the external fireball will change significantly. As Kv increases from 2.2 to 5.6, the external fireball shapes are always mushroom-shaped. However, the shapes of the fireball become elongated for Kv > 7.8, and even the external fireball presents a jet shape for Kv = 20.1. With the increasing of Kv from 2.2 to 20.1, The maximum external overpressure increases first, thereafter decreases, and finally increases.

Анализ мультигенных семейств вируса африканской чумы свиней

The article presents summarized data on the multigene families of the African swine fever virus (MGF). A feature of the ASF virus is the presence of a large number of multigene families. It is generally accepted that multigene family proteins are widely distributed in the African swine fever virus (ASF) genome and are generally classified into five families, including MGF-100, MGF-110, MGF-300, MGF-360, and MGF-505. The multigene families of the ASF virus are located in both the left and right variable regions of the genome. It is known that multigene families 110 and 300 are located on the left end of the genome, and MGS 100 on the right, and MGS360, MGS505 and MGS530 at both ends of the genome. Most MGS families have copies at each end of the genome. Multigene families are responsible for the virulence and replication of the ASF virus. Several genes belonging to the 360 and 505/530 families determine the host range of the ASF virus and its virulence. The 530 multigene family contains six different reading frames encoding an average of five hundred and thirty amino acids containing four highly conserved domains. MGS300 consists of three open translation frames encoding an average of three hundred amino acids containing three highly conserved domains. The amino-terminal regions of the proteins encoded by MGS-530 and 300 have significant similarity to each other, as well as to the corresponding regions. Most researchers believe that MGS evolved through a process of duplication and sequence divergence. Elements of multigene families are located close to each other and are read in only one direction.

Lattice Boltzmann method for studying dynamics of single rising bubble in shear-thickening power-law fluids

Bubble motion in non-Newtonian fluids is widely present in various industrial processes such as crude oil extraction, enhancement of boiling heat transfer, CO<sub>2</sub> sequestration and wastewater treatment. System containing non-Newtonian liquid, as opposed to Newtonian liquid, has shear-dependent viscosity, which can change the hydrodynamic characteristics of the bubbles, such as their size, deformation, instability, terminal velocity, and shear rate, and ultimately affect the bubble rising behaviors. In this work, the dynamic behavior of bubble rising in a shear-thickened fluid is studied by using an incompressible lattice Boltzmann non-Newtonian gas-liquid two-phase flow model. The effects of the rheological exponent <i>n</i>, the Eötvös number (<i>Eo</i>), and the Galilei number (<i>Ga</i>) on the bubble deformation, terminal velocity, and the shear rate are investigated. The numerical results show that the degree of bubble deformation increases as <i>Eo</i> grows, and the effect of <i>n</i> on bubble deformation degree relates to <i>Ga</i>. On the other hand, the terminal velocity of the bubbles increases monotonically and nonlinearly with <i>Ga</i> for given <i>Eo</i> and <i>n</i>, and the effect of <i>n</i> on the terminal velocity of the bubbles turns stronger as <i>Ga</i> increases. When <i>Ga</i> is fixed and small, the terminal velocity of the bubble increases and then decreases with the increase of <i>n</i> at small <i>Eo</i>, and increases with the increase of <i>n</i> when <i>Eo</i> is large; but when <i>Ga</i> is fixed and large, the terminal velocity of the bubbles increases with the increase of <i>n</i> in a more uniform manner. In addition, regions with high shear rates can be found near the left end and right end of the bubble. The size of these regions grows with <i>Eo</i> and <i>Ga</i>, exhibiting an initial increase followed by a decrease as <i>n</i> increases. Finally, the orthogonal experimental method is used to obtain the influences of the aforementioned three factors on the shear rate and terminal velocity. The order of influence on shear rate is <i>n</i>, <i>Ga</i> and <i>Eo</i> which are arranged in descending order. For the terminal velocity, <i>Ga</i> has the greatest influence, followed by <i>n</i>, and <i>Eo</i> has the least influence.

Predictive analysis of doubly Type-Ⅱ censored models

<p>The application of a doubly Type-Ⅱ censoring scheme, where observations are censored at both the left and right ends, is often used in various fields including social science, psychology, and economics. However, the observed sample size under this censoring scheme may not be large enough to apply a likelihood-based approach due to the occurrence of censoring at both ends. To effectively respond to this difficulty, we propose a pivotal-based approach within a doubly Type-Ⅱ censoring framework, focusing on two key aspects: Estimation for parameters of interest and prediction for missing or censored samples. The proposed approach offers two prominent advantages, compared to the likelihood-based approach. First, this approach leads to exact confidence intervals for unknown parameters. Second, it addresses prediction problems in a closed-form manner, ensuring computational efficiency. Moreover, novel algorithms using a pseudorandom sequence, which are introduced to implement the proposed approach, have remarkable scalability. The superiority and applicability of the proposed approach are substantiated in Monte Carlo simulations and real-world case analysis through a comparison with the likelihood-based approach.</p>

FNDC5 genetic polymorphism in patients with peripartum cardiomyopathy.

Late in pregnancy or soon after delivery, peripartum cardiomyopathy (PPCM) which is an uncommon type of cardiomyopathy, can develop. To assess the association between the level of irisin expression and (FNDC5) (rs3480) gene polymorphism with peripartum cardiomyopathy. This is a case control study included a thirty female patients with new-onset PPCM and sixty healthy females at the at the peripartum period in same time window for PPCM as a control. For each patient, comprehensive medical history was taken, full clinical assessment was done, ECHO., FNDC5 (rs3480) & Irisin assay. The left ventricle end diastolic dimensions &left atrium diameters were statistically significant higher in patients' group than controls' group (P=0.000 for all), Also left ventricular ejection fraction (%) was statistically significant lower in patients than controls and as regards irisin, its Mean ±SD was lower in patient group than control group (8.44±1.1 vs 10.65±2.31) with (p <0.001) which is considered a significant difference statistically. Irisin level was lower in peripartum cardiomyopathic patients when compared with normal individuals and regarding its genotype, the homotype A/A was higher than homotype G/G.

Simulation of temperature field and optimization of heat dissipation structure for lithium-ion power battery pack based on multi-objective function optimization

In order to improve the thermal power dissipation of batteries and reduce the maximum temperature difference of batteries, the air conditioning system using battery type was optimized. Using multi-objective optimization method based on orthogonal experiment and multiple rotations, the local optimum values of multi-objective were obtained: the left end height A of entrance area and the height B of air outlet were 9 mm and 28 mm, respectively, with a tolerance value C of 0.4 mm for battery spacing. The simulation results of this optimization model show that the maximum temperature difference of the battery volume is 306.627 K (33.477?C) and 3.815 K (3.815?C), respectively. Compared with the initial model, they are reduced by 9.55% and 25.89%, respectively. Compared with the single factor analysis optimization model, they are reduced by 0.36% and 20.27%, respectively, indicating that the multi-objective optimization results are better. This multi-objective programming solves the problem of different parameters of air conditioning heat dissipation model to some extent, and can provide reference for the optimization design of other models.

Effective orientifolds from broken supersymmetry

We recently proposed a class of type IIB vacua that yield, at low energies, four–dimensional Minkowski spaces with broken supersymmetry and a constant string coupling. They are compactifications with an internal five-torus bearing a five–form flux Φ and warp factors depending on a single coordinate. The breaking of supersymmetry occurs when the internal space includes a finite interval. A probe-brane analysis revealed a gravitational repulsion and a charge attraction of equal magnitude from the left end of the interval, together with a singularity at the other end. Here we complete the analysis revealing the presence, at one end, of an effective of negative tension and positive five–form charge. We also determine the values of these quantities, showing that , and characterize the singularity present at the other end of the interval, which hosts an opposite charge. Finally, we discuss various forms of the gravity action in the presence of a boundary and identify a self–adjoint form for its fluctuations. Invited contribution to the special issue of Journal of Physics A: Mathematical and Theoretical on ‘Fields, Gravity, Strings and Beyond: In Memory of Stanley Deser’

Indeterminate Continuously Inhomogeneous Beam under End Rotation: A Longitudinal Fracture Study

The present paper describes a theoretical analysis of the effect of the end rotation of a statically indeterminate beam structure on the behaviour of a longitudinal crack. The beam is made of a material that is continuously inhomogeneous along the beam thickness. Besides, the material has non-linear elastic behaviour. The left end of the beam is supported with an axial double rod, while the right end is rigidly fixed. There is no external mechanical loading on the beam. Thus, the only influence on the beam is the rotation of the beam left end. Equations for determination the curvatures and the coordinates of the neutral axes are worked out and solved together with equations for resolving the static indeterminacy. The response of the longitudinal crack to the rotation of the beam left end is studied by deriving the strain energy release rate. For this purpose the balance of the energy in the beam is analyzed. The strain energy release rate is verified by applying the integral, J. A parametric analysis is performed to evaluate the influence of the beam end rotation and other factors on the longitudinal fracture.

The Production of Recombinant African Swine Fever Virus Lv17/WB/Rie1 Strains and Their In Vitro and In Vivo Characterizations.

Lv17/WB/Rie1-Δ24 was produced via illegitimate recombination mediated by low-dilution serial passage in the Cos7 cell line and isolated on PAM cell culture. The virus contains a huge ~26.4 Kb deletion in the left end of its genome. Lv17/WB/Rie1-ΔCD-ΔGL was generated via homologous recombination, crossing two ASFV strains (Lv17/WB/Rie1-ΔCD and Lv17/WB/Rie1-ΔGL containing eGFP and mCherry markers) during PAM co-infection. The presence of unique parental markers in the Lv17/WB/Rie1-ΔCD-ΔGL genome indicates at least two recombination events during the crossing, suggesting that homologous recombination is a relatively frequent event in the ASFV genome during replication in PAM. Pigs infected with Lv17/WB/Rie1-Δ24 and Lv17/WB/Rie1/ΔCD-ΔGL strains have shown mild clinical signs despite that ASFV could not be detected in their sera until a challenge infection with the Armenia/07 ASFV strain. The two viruses were not able to induce protective immunity in pigs against a virulent Armenia/07 challenge.

Dynamic characteristics analysis of a rotor system with loose support considering internal friction in couplings

Along with the rotating machinery advances toward high speeds, the significance of the excitation force of the seal fluid in the rotor system is growing, which can cause serious accidents. Most of the previous research on rotors in rotating machinery has predominantly focused on the effects of misalignment in couplings. In this article, a novel model is proposed, introducing an analytical approach that combines both internal friction in couplings and loosening support faults. Additionally, an analysis and discussion of the vibration characteristics of the rotating system under the influence of internal friction are presented. This method allows for a more comprehensive assessment of the performance of rotors in engineering applications. Assuming that the left support of the rotor is loose, this model focused on how various factors such as rotor speeds, eccentricity, seal disc mass, and left-end support mass affect the labyrinth seal rotor system's dynamic characteristics. Based on the findings, The emergence of internal friction forces advances the chaos of the rotor. It seems that as the rotating speed increases, there will be a small frequency range, resulting in fluid oscillation, and the system stability will be reduced at this time. The improvement in the seal disc's quality has minimal impact on the stability of the left journal, but it will reduce the stability of the seal disc. The increase in the mass of the left end support will increase the stability of the movement at the left journal and reduce the stability of the movement at the seal disc.

A bipolar-valued fuzzy set is an intersected interval-valued fuzzy set

This paper shows that a bipolar-valued fuzzy set and a special interval-valued fuzzy set, whose cut-off point of left and right ends of the interval-valued membership is λ(0<λ<1), are identical from a mathematical point of view. All results on bipolar-valued fuzzy sets can be obtained by corresponding results of interval-valued fuzzy sets or fuzzy sets. This paper does not completely reject bipolar-valued fuzzy sets, but points the way for such research.

Understanding heterogeneous mechanisms of heart failure with preserved ejection fraction through cardiorenal mathematical modeling.

In contrast to heart failure (HF) with reduced ejection fraction (HFrEF), effective interventions for HF with preserved ejection fraction (HFpEF) have proven elusive, in part because it is a heterogeneous syndrome with incompletely understood pathophysiology. This study utilized mathematical modeling to evaluate mechanisms distinguishing HFpEF and HFrEF. HF was defined as a state of chronically elevated left ventricle end diastolic pressure (LVEDP > 20mmHg). First, using a previously developed cardiorenal model, sensitivities of LVEDP to potential contributing mechanisms of HFpEF, including increased myocardial, arterial, or venous stiffness, slowed ventricular relaxation, reduced LV contractility, hypertension, or reduced venous capacitance, were evaluated. Elevated LV stiffness was identified as the most sensitive factor. Large LV stiffness increases alone, or milder increases combined with either decreased LV contractility, increased arterial stiffness, or hypertension, could increase LVEDP into the HF range without reducing EF. We then evaluated effects of these mechanisms on mechanical signals of cardiac outward remodeling, and tested the ability to maintain stable EF (as opposed to progressive EF decline) under two remodeling assumptions: LV passive stress-driven vs. strain-driven remodeling. While elevated LV stiffness increased LVEDP and LV wall stress, it mitigated wall strain rise for a given LVEDP. This suggests that if LV strain drives outward remodeling, a stiffer myocardium will experience less strain and less outward dilatation when additional factors such as impaired contractility, hypertension, or arterial stiffening exacerbate LVEDP, allowing EF to remain normal even at high filling pressures. Thus, HFpEF heterogeneity may result from a range of different pathologic mechanisms occurring in an already stiffened myocardium. Together, these simulations further support LV stiffening as a critical mechanism contributing to elevated cardiac filling pressures; support LV passive strain as the outward dilatation signal; offer an explanation for HFpEF heterogeneity; and provide a mechanistic explanation distinguishing between HFpEF and HFrEF.

Biventricular unloading with Impella on top of veno-arterial membrane oxygenation improves short- and long-term survival in refractory post-cardiac arrest cardiogenic shock

Abstract Background Patients with refractory post-cardiac arrest (CA) cardiogenic shock (RCS) may present with LV-failure, biventricular failure or even combined cardiopulmonary failure. Mechanical circulatory support (MCS) with Impella or veno-arterial membrane oxygenation (vaECMO) have emerged as an alternative strategy in order to stabilize the heart function without the detrimental effects of catecholamines or to bridge these patients in definite therapies. However, the selection of the appropriate MCS device should be tailored according to the underlying pathophysiology and properties of the respective MCS device. Especially vaECMO patients may show signs of LV overloading, causing pulmonary edema, LV distension and thus compromising LV myocardial recovery. Nowadays there is no data concerning the role of biventricular unloading with an Impella on top of a vaECMO in the homogenous group of post-CA RCS. Purpose To report our experience from the combined use of Impella (2.5 and CP) on top of a vaECMO in the homogenous group of patients with post-CA RCS. Methods Single center study of consecutive patients with biventricular unloading with Impella after initial vaECMO support over a 6-year period suffering from post-CA RCS. Propensity scoring matching analysis was used to account for the differences in baseline data between the two groups. Results A total of 91 patients underwent vaECMO support for RCS, whereas in another 32 patients initial vaECMO support was escalated with an Impella (75% CP) (BiVent group). Mean age was 60.88 ± 9.8 and 98 (80%) patients were male. Survival rates were similar in both groups (hospital survival: BiVent 40.6% and vaECMO 33%, p=0.52; 12-month survival BiVent 37.5% and vaECMO 31.9%, p=0.67). After adjustment for baseline difference with propensity scoring matching analysis, survival rates were significantly better in the BiVent group (hospital and 12-month survival: BiVent 50% and vaECMO 17%, p=0.03 (Figure 1). Vasopressor doses and lactate levels decreased significantly more firmly in the BiVent group within 72 h on biventricular support compared to vaECMO (p&amp;lt;0.05). Moreover, the patients in the BiVent group demonstrated a greater functional recovery of the LV at 96 hours after admission compared to vaECMO patients (Figure 2). Conclusions Impella on top of vaECMO improves short- and long-term survival in patients with post-cardiac arrest refractory cardiogenic shock leading to a better restoration of the left ventricle and end organ function.

The acute hemodynamic effects of sodium lactate infusion: increased cardiac output and decreased afterload in a randomized trial in pigs

Abstract Background Lactate is traditionally acknowledged as a by-product of anaerobic glucose metabolism. Recently, however, lactate has been proven to be a preferred oxidative substrate for stressed myocardium. Studies have shown that exogenous lactate infusion provides beneficial hemodynamic effects including increased cardiac output (CO). Nevertheless, the exact mechanism of action underlying the hemodynamic effects of lactate infusion has not been fully elucidated. Aim To identify the cardiovascular mechanisms behind the acute hemodynamic effects of exogenous sodium lactate infusion in an experimental model of healthy human-sized pigs. Methods We performed a randomized, assessor-blinded crossover study in eight female 60 kg pigs. In randomized order, the pigs received an infusion with 1 M sodium lactate for two hours and a control infusion with iso-osmolar and isovolumetric sodium chloride for two hours. The two infusion periods were separated by a one-hour washout period. We measured CO and pulmonary pressures hourly with a pulmonary artery catheter. A pressure-volume admittance catheter was inserted in the left ventricle to assess measures of cardiac efficiency, contractility, afterload, and preload. Hemodynamic measures as arterial blood pressure, heart rate, and mixed venous saturation (SvO2) were measured hourly as well. The study followed the principles of laboratory animal care (NIH Publication no. 85-23 revised 1985) and national and European legislations. Results Lactate levels increased by 9.9 mmol/L (95% CI 9.1 to 11.0) and CO increased by 2.0 L/min (95% CI 1.2 to 2.8) during lactate infusion as compared with the control period (figure 1). During lactate infusion, ejection fraction increased by 16.0 percentage points (95% CI 1.9 to 31.0) and heart rate by 21 bpm (95% CI 9 to 32) compared with control. Arterial elastance decreased by -1.1 mmHg/ml (95% CI -2.1 to -0.18). Lactate infusion also increased cardiac efficiency, SvO2, arterial pH, and arterial glucose concentration significantly. The infusion of lactate led to no changes in systemic arterial pressure nor pulmonary pressures including pulmonary artery wedge pressure. Also, no changes were found in left ventricle end systolic elastance (contractility). Futhermore, no change in left ventricle end-diastolic volume or -pressure (preload) were observed during lactate infusion compared with the control (figure 2). Conclusion High dose lactate infusion increased cardiac output by reducing afterload. No changes in left ventricular contractility or -preload were observed.Fig 1:Lactate concentration and COFig 2:Changes of endpoint parameters

Coronary Flow Reserve Changes after Angiotensin Receptor-Neprilysin Inhibitor Treatment in Heart Failure with Reduced Ejection Fraction.

Sacubitril/valsartan has been shown to reduce hospital admissions and even mortality for heart failure. In heart failure and acute coronary syndrome, the effects of sacubitril/valsartan have been studied, but the effect on coronary artery flow is not known. We aimed to understand the effect of sacubitril/valsartan on coronary artery flow by using echocardiographic coronary flow reserve (CFR). Thirty-six patients (17 ischemic and 19 non-ischemic) with heart failure with reduced ejection fraction (EF of < 40%) eligible for sacubitril/valsartan treatment and 21 normal controls were recruited. The study group and controls were similar with regard to gender, smoking status, and age distribution (p = 0.874, p = 0.709, and p = 0.765, respectively). Blood pressure, heart rate, 6-minute walk test (6MWT), N terminal pro B type natriuretic peptide (NT-pro-BNP) level, standard echocardiography, from where left anterior descending mid-distal flow was seen, baseline peak diastolic flow rate and 2 minutes after dipyridamole infusion, and hyperemic peak diastolic flow rate were measured, and CFR with echocardiography was assessed prior to and at 6 months after sacubitril/valsartan initiation. Baseline peak diastolic flow rate did not exhibit a significant difference at 6 months (p = 0.143), but hyperemic peak diastolic flow rate, CFR, EF (%), and 6MWD values were significantly increased (all p < 0.001), and New York Heart Association Functional Class, NT-pro-BNP (pg/mL), left ventricule end diastolic diameter (mm), and left ventricule end systolic diameter (mm) values were significantly decreased (all p < 0.001) after sacubitril/valsartan treatment. Sacubitril/valsartan significantly alters coronary blood flow, especially its dynamic features, in patients with heart failure with reduced ejection fraction.