Aperiodic Research Articles

Myocardial contractile function in the post-traumatic period of cardiac contusion in rats with different stress resistance: A preclinical experimental randomized trial

Background. Pathogenesis of cardiac contusion involves primary traumatic and secondary hypoxic mechanisms of myocardial contractile function depression as well as body reactions aimed at adapting to altered environment. A significant part of these reactions is realized in the context of stress. The intensity of the stress component in myocardial dysfunction is largely determined by the individual stress reactivity of the body. Objectives. To assess the contractile function and functional reserves of the myocardium of rats with a high and low level of stress resistance in the post-traumatic period of cardiac contusion. Methods. A preclinical experimental randomized trial involved 134 white mature nonlinear male rats weighing about 270 g. The animals were divided by sequentially performed Open Field and Porsolt Forced Swim tests into 2 groups: group 1 — animals with low stress resistance, group 2 — animals with high stress resistance. Within each group, the animals were randomized into control and experimental subgroups. In the experimental subgroups, 6, 12 and 24 hours after simulating cardiac contusion, the force and rate indicators of myocardial contractility were evaluated using the Fallen isolated heart model. The summary measures of the study included assessing the contractile force and rate of isolated hearts of rats with low and high stress resistance, particularly under conditions of high-frequency rhythm load (ranging from 4.0 to 8.3 Hz) during the post-traumatic period of cardiac contusion. Data analysis was performed using software packages MS Office 2013 (Microsoft Corporation, USA) and Statistica, v. 10 (StatSoft, USA). The differences were considered to be statistically significant at p < 0.05. Results. 6, 12 and 24 hours after simulating a cardiac contusion, contractile force and rate of isolated hearts decreased in group 1 and group 2. In low stress-resistant animals, immediately following the stabilization period and during high-frequency rhythm test, the contractility force and rate in isolated hearts were statistically significantly lower (p = 0.0008) compared to those recorded in highly stress-resistant individuals. During the stimulation of a high-frequency rhythm, isolated hearts in the experimental group revealed diastolic dysfunction at all time points. In highly stress-resistant animals, diastolic dysfunction occurred at a heart rate of 300 min-1 and above, whereas in low stress-resistant animals, it manifested at a heart rate of 240 min-1 and above. At the same heart rate, diastolic dysfunction in low stress-resistant animals was statistically significantly greater (p = 0.0008) compared to that of highly resistant animals. Conclusion. The post-traumatic period following experimental myocardial contusion is characterized by a reduction in the force and rate of myocardial contractility, as well as a decrease in functional reserves of the myocardium, regardless of stress resistance. High stress resistance is associated with better preservation of cardiac contractile function and contractility reserves, whereas low stress resistance correlates with a more pronounced degree of myocardial dysfunction and a significant reduction in functional reserves of the contused heart. Differences in the severity of contractile dysfunction under conditions of high and low body resistance to stress can be attributed to varying degrees of secondary myocardial damage in the contused area, resulting from the misbalance between stress-activating and stress-limiting mechanisms involved in the development of secondary damage.

Unraveling the thrombin–Alzheimer’s connection: Oral anticoagulants as potential neuroprotective therapeutics

In Alzheimer’s disease (AD), toxic amyloids formed by amyloid-β (Aβ) proteins and tau are implicated in the development of inflammatory, vascular, and neurodegenerative brain disorders. Thrombin has also been recognized as a proteopathic factor involved in Aβ-induced neurovascular dysfunction. Vascular Aβ activates the contact system in the blood, stimulating the production of inflammatory bradykinin and procoagulant thrombin. Thrombin, in turn, triggers inflammation, platelet activation, and the formation of fibrinolysis-resistant, Aβ-containing fibrin clots, leading to Aß-type cerebral amyloid angiopathy and associated neuropathology. Targeting thrombin with oral anticoagulants can normalize proinflammatory and prothrombotic states, counteracting the neurovascular consequences of AD. Pre-clinical studies have shown that such interventions preserve vascular and blood–brain barrier integrity, improve cerebral blood flow and brain perfusion, and reduce parenchymal accumulations of toxic Aβ, tau, fibrin(ogen), and thrombin. These effects mitigate neuroinflammatory and neurodegenerative processes, ultimately preserving cognitive functions for a longer period. Recent observational clinical studies in patients with atrial fibrillation (AF) demonstrated that treatment with direct oral anticoagulants (DOACs) or vitamin K antagonists (VKAs) reduced the risk of dementia by up to 48% compared to non-users. The anti-dementia effects were most prominent in elderly patients but were also observed in individuals with low AF risk or newly diagnosed AF. In addition, DOACs reduced the risk of intracranial hemorrhage by approximately 50% compared to VKAs. The current review highlights the potential neuroprotective role of DOACs in AD. By preventing excessive thrombin generation caused by Aβ pathology, DOACs could protect vascular and neuronal functions, thereby slowing cognitive decline. DOACs, such as dabigatran, apixaban, and rivaroxaban, warrant further clinical investigation for their potential repurposing as disease-modifying therapeutics in AD.

Exploring the Diversity of Kink Solitons in (3+1)-Dimensional Wazwaz–Benjamin–Bona–Mahony Equation

The Wazwaz–Benjamin–Bona–Mahony (WBBM) equation is a well-known regularized long-wave model that examines the propagation kinematics of water waves. The current work employs an effective approach, called the Riccati Modified Extended Simple Equation Method (RMESEM), to effectively and precisely derive the propagating soliton solutions to the (3+1)-dimensional WBBM equation. By using this upgraded approach, we are able to find a greater diversity of families of propagating soliton solutions for the WBBM model in the form of exponential, rational, hyperbolic, periodic, and rational hyperbolic functions. To further graphically represent the propagating behavior of acquired solitons, we additionally provide 3D, 2D, and contour graphics which clearly demonstrate the presence of kink solitons, including solitary kink, anti-kink, twinning kink, bright kink, bifurcated kink, lump-like kink, and other multiple kinks in the realm of WBBM. Furthermore, by producing new and precise propagating soliton solutions, our RMESEM demonstrates its significance in revealing important details about the model behavior and provides indications regarding possible applications in the field of water waves.

The energy-frequency diagram of the (1+1)-dimensional Φ4 oscillon

Two different methods are used to study the existence and stability of the (1+1)-dimensional Φ4 oscillon. The variational technique approximates it by a periodic function with a set of adiabatically changing parameters. An alternative approach treats oscillons as standing waves in a finite-size box; these are sought as solutions of a boundary-value problem on a two-dimensional domain. The numerical analysis reveals that the standing wave’s energy-frequency diagram is fragmented into disjoint segments with ωn+1< ω < ωn, where ωn = ω0/(n + 1), n = 0, 1, 2, ., and ω0 is the endpoint of the continuous spectrum (mass threshold of the model). The variational approximation involving the first, zeroth and second harmonic components provides an accurate description of the oscillon with the frequency in (ω1, ω0), but breaks down as ω falls out of that interval.

Assessing the impact of virtual reality on the restoration of motor function in the acute period of ischemic stroke

Aim: to evaluate the effectiveness of using virtual reality to restore motor function in patients in the acute period of ischemic stroke.Material and methods. We studied 207 patients in the acute period of ischemic stroke, who were divided into two groups by randomization: study group – 105 patients, comparison group – 102 patients. All patients received all necessary standardized therapy. Patients in the study group additionally received classes using the ReviVR device. Efficacy was assessed using the NIHSS, FMA-LE, and BBS scales.Results. On all scales studied, patients in the study group demonstrated better results in relation to the comparison group, both in terms of the final result and in terms of the level of change in indicators during the rehabilitation process. The use of virtual reality made it possible to reduce disability on the NIHSS scale to 7.0 (4.0; 9.0) points, which is better than the results of the comparison group – 9.0 (5.0; 13.0) points with a high level of significance p &lt; 0.001. The increase in motor function according to FMA-LE in the study group was higher and amounted to 21.0 (15.0; 24.0) points versus 18.0 (7.0; 22.0) points in the comparison group with a significance level of p = 0.002. The study group also showed better results on the BBS scale – 26.0 (17.0; 34.0) versus 18.0 (5.0; 29.0) points with a significance level of p &lt; 0.001.Conclusion. The use of virtual reality together with standardized therapy in the acute period of ischemic stroke is effective in restoring motor function of the affected lower limb, improving balance and reducing general disability in general.

Optical dromions for M-fractional Kuralay equation via complete discrimination system approach along with sensitivity analysis and quasi-periodic behavior

This paper investigates new analytical wave solutions for the fractional Kuralay-IIB equations (FK-IIBE), including a new definition of the fractional derivative. This model works in disciplines such as ferromagnetic materials, optical fibers, wave mixing, and nonlinear optics. The integrable motion of space curves can be determined by our governing model. This research holds great importance in the area of optical fibers, exact and analytical solitons solution. The polynomial method’s complete discrimination system (CDSPM) is used to identify a variety of exact and analytical soliton solutions such as periodic, hyperbolic, rational, Jacobian elliptic (JE), and trigonometric functions. Additionally, we also convert the JE function into a solitary wave (SW) solution. To provide a comprehensive understanding of the dynamic aspects of the system, we also address bifurcation points, quasi-periodic behavior, sensitivity analysis, Poincarè maps, time series profile, and critical solution conditions. The research offers straightforward, efficient algorithms that can consistently and effectively address FK-IIBE. Machine learning technologies are also utilized to satisfy the criteria defined by dynamic analysis. Python regression learner tools are used for reverse engineering to analyze the mathematical model’s equilibrium based on parameter intervals and thresholds determined by dynamical analysis.

The Effect of Gum Chewing on Gastrointestinal System Functions in Patients Undergoing Colorectal Surgery: A Systematic Review

In the postoperative period, gas and secretions in the stomach and small and large intestines due to delayed motility of the gastrointestinal system cause abdominal bloating, nausea, vomiting and pain, and this situation negatively affects the comfort level of patients. Chewing gum is among the methods used to prevent ileus after surgery. Chewing gum activates the cephalic vagal reflex and stimulates bowel function in the postoperative period. In this article, the effect of chewing gum in preventing ileus after colorectal surgery and the factors affecting the success rate are reviewed in the light of current literature.

Modified infra-promontorium trans-channel approach to the petrous apex. Case report

This article describes the approach to the petrous pyramid developed at National Medical Research Center of Otorhinolaryngology, namely an endoscopy – microscopy-guided modified trans-channel infra-promontorium approach with internal carotid artery retraction maneuver in patients with lesions of the petrous pyramid but with preserved hearing. A clinical report describing the apical cholesteatoma of the petrous pyramid and the use of this approach are presented. Anatomical and functional features after the surgery are also described. The purpose of this paper is advancing of the surgical approach to the petrous pyramid with the possibility of hearing preservation. The results of surgical treatment in lesions of the petrous pyramid were evaluated in the immediate and distant periods. The functions of facial mimic muscles were evaluated immediately after the surgery, in 6 months, and in one year. The functions of facial mimic muscles remained at the baseline level during the whole follow-up period. The pure tone audiogram demonstrated the preserved hearing function in the postoperative period. Complete elimination of the pathological process was achieved in all cases (n=15); according to the MRI of the temporal bones, no relapses occurred in a year. The surgical approach proposed for patients with the lesions of the petrous pyramid enables complete removal of the pathological process from the petrous pyramid with the preservation of hearing and facial functions, based on the subjective examinations (audiometry, facial function diagnosis) and radiology (CT and MRI of temporal bones) at the preoperative stage.

Framework of acoustic analysis and shape optimization for three-dimensional doubly periodic multilayered structures

In this research, a framework of acoustic analysis and shape optimization, based on isogeometric boundary element method (IGA-BEM), is proposed for three-dimensional doubly periodic multilayered structures. The study addresses a gap in the literature by focusing on the shape optimization of such structures, which has not been extensively explored previously. The interface between different acoustic media is an infinite doubly periodic surface, which can be constructed by an open non-uniform rational B-splines. A periodic IGA-BEM is developed for the sound field analysis of the doubly periodic multilayered structure, in which the Ewald method is used to accelerate the calculation of periodic Green function. Furthermore, the shape derivative of the doubly periodic multiple boundaries is derived by imposing boundary perturbation and using the adjoint variable method. The control points of the NURBS surfaces are defined as the shape design variables, and all shape sensitivities can be quickly calculated by discretizing the shape derivative formula. Finally, in according with shape sensitivities, the corresponding shape optimization problem is solved by the method of moving asymptotes, so that the optimized shape design can be obtained. A series of numerical examples validates the accuracy and applicability of the proposed approaches.

Geometric Algebra Framework Applied to Single-Phase Linear Circuits with Nonsinusoidal Voltages and Currents

We apply a well known technique of theoretical physics, known as geometric algebra or Clifford algebra, to linear electrical circuits with nonsinusoidal voltages and currents. We rederive from the first principles the geometric algebra approach to the apparent power decomposition. The important new point consists of endowing the space of Fourier harmonics with a structure of a geometric algebra (it is enough to define the Clifford product of two periodic functions). We construct a set of commuting invariant imaginary units which are used to define impedance and admittance for any frequency.

Robust unsupervised 5D seismic data reconstruction on regular and irregular grids

Seismic data reconstruction has become a central focus in seismic data processing, addressing challenges posed by sparse sampling due to physical and budgetary constraints. The advent of 5D acquisition methodologies marks a significant advancement in the quality and completeness of seismic data sets. Most traditional 5D reconstruction methods commonly use the fast Fourier transform (FFT), requiring regular grids and preliminary 4D binning before 5D interpolation. Discrete Fourier transform and nonequidistant FFT can honor the original irregular coordinates. However, when using exact locations, these methods become computationally expensive. We introduce an unsupervised deep-learning methodology to learn a continuous function across the sampling points in seismic data, facilitating reconstruction on regular and irregular grids. The network comprises a multilayer perceptron with linear layers and element-wise periodic activation functions. It excels at mapping the input coordinates to the corresponding seismic data amplitudes without relying on external training sets. The network’s intrinsic low-frequency bias is crucial in prioritizing acquiring self-similar features over high-frequency and incoherent ones during training. This characteristic mitigates incoherent noise in seismic data, such as random and erratic components. To assess the robustness of the unsupervised reconstruction technique, we conduct comprehensive evaluations using synthetic data examples sampled regularly and irregularly, as well as field-data examples with and without binning. The findings demonstrate the efficacy of our deep-learning framework in achieving resilient and accurate seismic data reconstruction across diverse sampling scenarios.

Finite temperature fermionic condensate and energy–momentum tensor in cosmic string spacetime

Here we analyze the expectation value of the fermionic condensate and the energy–momentum tensor associated with a massive charged fermionic quantum field with a nonzero chemical potential propagating in a magnetic-flux-carrying cosmic string in thermal equilibrium at finite temperature T. The expectation values of the fermionic condensate and the energy–momentum tensor are expressed as the sum of vacuum expectation values and the finite temperature contributions coming from the particles and antiparticles excitation. The thermal expectations values of the fermionic condensate and the energy–momentum tensor are even periodic functions of the magnetic flux with period being the quantum flux, and also even functions of the chemical potential. Because the analyses of vacuum expectation of the fermionic condensate and energy–momentum tensor have been developed in literature, here we are mainly interested in the investigation of the thermal corrections. In this way we explicitly study how these observable behaves in the limits of low and high temperatures, and also for points near the string. Besides the analytical discussions, we included some graphs that exhibit the behavior of these observable for different values of the physical parameters of the model.

Multi-temporal drought rarity curves—A yearly classification of meteorological drought severity in France

Droughts are recurrent phenomena that present a large variety of space and time patterns making rather difficult the assessment of their rarity and the comparison between events.Our study focuses on the “memory effect” of meteorological drought over France using the daily raingauge network maintained by Météo-France over 1950–2022. The proposed easy tool of rarity curves analyzes how drought events build and persist across time. The approach is purely statistic, assuming that drought consequences depend on the probability of non exceedance (“rarity”) of antecedent rainfall accumulations. In order to cover a large spectrum of “memory effects”, we consider a continuum of accumulation periods ranging from a few weeks to several years. The rarity curve of a given year displays the most severe rarity values encountered during the year as a function of the various accumulation periods (256 values ranging from 4 to 260 weeks in our case).Over the study period of 1950–2022 we show how the shape of rarity curves discriminate short- and long-term historical droughts. A k-means algorithm proves to be useful to classify the different years into typical drought situations from continuous drying to continuous wetting over the antecedent five years. Looking at the chronology of the found clusters also allows studying how droughts build and persist across time.

51 - Pelvic floor muscle function in early postpartum period and perineal injury- is there a difference?

51 - Pelvic floor muscle function in early postpartum period and perineal injury- is there a difference?

Planar structured materials with extreme elastic anisotropy

Designing anisotropic structured materials by reducing symmetry results in unique behaviors, such as shearing under uniaxial compression. While rank-deficient materials such as hierarchical laminates have been shown to exhibit extreme elastic anisotropy, there is limited knowledge about the fully anisotropic elasticity tensors achievable with single-scale fabrication techniques. No established upper and lower bounds on anisotropic moduli exist. In this paper, we estimate the range of anisotropic stiffness tensors achieved by single-scale two-dimensional structured materials. We first develop a database of periodic anisotropic single-scale unit cell geometries using linear combinations of periodic cosine functions. The database covers a wide range of anisotropic elasticity tensors, which are then compared with the elasticity tensors of hierarchical laminates. We identify the regions in the property space where hierarchical design is necessary to achieve extremal properties. We demonstrate a method to construct various 2D functionally graded structures using this cosine function representation. These graded structures seamlessly interpolate between unit cells with distinct patterns, allowing for independent control of several functional gradients, such as porosity, anisotropic moduli, and symmetry. When designed with unit cells positioned at extreme parts of the property space, these graded structures exhibit unique mechanical behaviors such as selective strain energy localization, compressive strains under tension, and localized rotations.

Review In Fourier series

It is known that Fourier series are one of linear transformations and have many uses in mathematics, physics, engineering…etc. It is used to influence on periodic functions that repeats in a certain period to transform it into a sum of sine and cosine functions also used for non-periodic functions, as we will notice, and it has many other uses. In this article, I study, with examples, the important uses of Fourier series in physics, engineering, and mathematics, with proofs and examples where it necessary. One of results that we have reached in this article is that use Fourier series to facilitated a solution of differential equations in particular partial differential equations by the sinusoidal part of it, also obtaining the best approximation element for a particular function by means of its mathematical mean which called Feger operators. Moreover, there are more than one auxiliary conclusion for, example if a function has two different periods, then the sum of these periods, its subtraction, and its multiplying by constant, will be a new period for this function. Here, I refer to another conclusion that, Fourier series itself do not give the best approximation element for a particular function.

Моделирование краниофациальных повреждений, анализ сроков регенерации и показаний к хирургической коррекции

The purpose of the experiment. Experimental modeling of craniofacial injuries, analysis of oculomotor function and regeneration in the post-traumatic period. Materials and methods. In the experiment, 48 sexually mature males of the Wistar breed were hit with a blunt hammer on a pre-determined area on the muzzle. According to the MS CT data, the nature of the displacement of bone fragments and the presence of muscle interposition were visualized. In the post-traumatic period, behavioral activity in the Actimeter device was analyzed. Results and discussion. Taking into account the thickness of the bone, the localization of the buttress at the place of applied force in the rodent, the hypothesis of energy absorption with its propagation through the bone structures of the orbits, and their subsequent displacement, was confirmed. Conclusions. In 38% of animals (groups 2 and 4), after impact to the postero lateral segment of the lower wall of the orbit, type 2 fracture of the cheekbone-orbital complex was recorded. In the posttraumatic period, a violation of behavioral activity was registered, which required prompt correction of displaced fragments. Upon impact to the central segment, in 50% of cases, 1 type of fracture was formed, without deviations in behavioral activity and without the need for surgical treatment.

Controllability and Optimal Fast Operation of Nonlinear Systems

A new method for solving the problem of controllability and optimal transient behavior of nonlinear systems subject to boundary conditions and constraints on control values was proposed. Unlike existing methods, this new approach is based on constructing a general solution of the integral equation for a linear controlled system, followed by transforming the original problem into a special initial optimal control problem. We propose a new method for studying the global asymptotic stability of dynamical systems with a cylindrical phase space with a countable equilibrium position based on a non-singular transformation of the equation of motion and estimation of improper integrals along the solution of the system. Conditions for global asymptotic stability were obtained without involving any periodic Lyapunov function, as well as the frequency theorem. The effectiveness of the proposed method is shown with an example.

Partially extended oscillation and nonoscillation theorems for half‐linear Hill‐type differential equations with periodic damping

This study addressed the oscillation problems of half‐linear differential equations with periodic damping. The solution space of any linear equation is homogeneous and additive. Generally, by contrast, the solution space of half‐linear differential equations is homogeneous but not additive. Numerous oscillation and nonoscillation theorems have been devised for half‐linear differential equations featuring periodic functions as coefficients. However, in certain cases, such as applying Mathieu‐type differential equations to control engineering, which is a typical example of the Hill equation, some oscillation theorems cannot be applied. In this study, we established oscillation and nonoscillation theorems for half‐linear Hill‐type differential equations with periodic damping. To prove the results, we used the Riccati technique and the composite function method, which focuses on the composite function of the indefinite integral of the coefficients of the target equation and an appropriate multivalued continuously differentiable function. Furthermore, we discuss the special case of the oscillation constant of a damped half‐linear Mathieu equation.

The impact of high-intensity interval training on women's health: A bibliometric and visualization analysis.

High-intensity interval training (HIIT) can significantly improve health indicators such as cardiopulmonary function, metabolic efficiency, and muscle strength in a short period. However, due to significant physiological and metabolic differences between males and females, the effects of HIIT vary between genders. Therefore, exploring the specific impacts of HIIT on women's health is crucial. Although there is a considerable amount of individual research on the impact of HIIT on women's health, a systematic bibliometric analysis is still lacking. Publications related to HIIT in women's health were retrieved from the Web of Science Core Collection database, and tools like Microsoft Office Excel 2021, VOSviewer, and Citespace were used to create visualized tables and views. The study included 808 publications distributed across 1234 institutions in 61 countries, authored by 3789 researchers. The United States, Australia, and Canada lead in this domain. Researchers like Astorino TA and Gibala MJ are notably influential in this field. The research has been prominently published in specific academic journals and widely cited by high-impact journals. Highly cited and bursting documents primarily discuss the effects of HIIT on metabolic adaptation, muscle adaptation, cardiovascular health, insulin sensitivity, and exercise performance. Frequent keywords include "aerobic exercise," "sprint interval training," "resistance training," "obesity," "body composition," "aging," and "insulin resistance." Keyword burst analysis reveals that early studies focused primarily on basic concepts and training models, which then expanded to specific physiological responses, applications in particular populations, and impacts on specific diseases. This field has emerged as a research hotspot with international characteristics and extensive academic productivity. Journals and cited journals hold high academic influence, with highly cited and bursty references laying a solid theoretical and practical foundation for the field. In the rapid development of the past decade, research hotspots and frontier directions such as metabolic adaptation, muscle adaptation, cardiovascular health, exercise performance, and personalized training plans have been formed.