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Mathematical frameworks for left ventricular assist device therapy: Ventricular mechanics, blood rheology, haemodynamics, control, and nonlinear dynamics

Mohsen Bakouri Ilyas Khan Khalid Sultan M. Alharbi Andrey V. Savkin

Publication Name: Progress in Biophysics and Molecular Biology

Publication Date: 2026-09-01

Volume: 201

Issue: Unknown

Page Range: 152-174

Description:

Ventricular assist devices (VADs) integrate multiple branches of applied mechanics within a single implanted system, spanning rotor-scale haemodynamics, nonlinear ventricular wall mechanics, blood trauma, and closed-loop control under changing physiological loads. This review aims to unify five mathematical frameworks central to VAD modelling: ventricular mechanics, blood rheology and damage, partial differential equation (PDE)-based device haemodynamics, pump engineering, and nonlinear heart–device dynamics. By bringing these domains together, the review clarifies their interactions and highlights unresolved mathematical challenges that limit progress in design, control, and prediction. An expository narrative review was conducted in accordance with the Scale for the Assessment of Narrative Review Articles (SANRA); a completed SANRA checklist is provided as Supplementary Material. Relevant literature was identified through targeted searches of PubMed, Scopus, and Web of Science, supplemented by citation tracking. Studies were selected for mathematical relevance, with emphasis on formulations that recur across VAD research, reveal model limitations, or connect analytical structure to clinically important complications. Major LVAD complications, including pump thrombosis, haemolysis, suction instability, and acquired von Willebrand syndrome, map onto distinct but interacting mathematical domains. Important cross-disciplinary links emerge between statistical mechanics and continuum damage models, between bifurcation theory and proportional–integral controller design, and between reduced-order cardiovascular models and full fluid–structure interaction simulations. Several formulations currently used in clinical, or engineering practice appear to extend beyond their original validation range. The mathematical problems underlying VAD therapy are strongly coupled and, in several areas, remain open. Advances in fluid–structure interaction theory, first-principles haemolysis modelling, and bifurcation analysis of the heart–pump oscillator could substantially improve device design, controller safety, and clinical outcome prediction.

Open Access: Yes

DOI: 10.1016/j.pbiomolbio.2026.07.001

The Impact System of Science Centers and their Activities, in Support of Public Education and Career Guidance, during the COVID Pandemic

Attila Pongracz Szabolcs Rákosi

Publication Name: Acta Polytechnica Hungarica

Publication Date: 2024-01-01

Volume: 21

Issue: 3

Page Range: 73-92

Description:

This paper investigates the complex impact system of the science centers, that play a key role in STEM career orientation and a draft model, for measuring these impacts. A review of the range of science centers in Hungary and an examination of the location of them provides an overview of this industry. Presentation diverse goals of science centers, their functions, along with the spatial effects of different activities, based on the comparative analysis of two institutions is presented herein. In addition to that, the paper also discusses the rural development impacts of science centers through a promising practice, and investigates innovative ways in which science center’s support public education and STEM career guidance during the COVID-19 pandemic. This research is based on the review of the current international literature on science centers. Subsequently, the Hungarian science center ecosystem is described through the analysis of public data, supplemented by the authors' personal, professional experiences in the analysis of the institutions and projects presented using a case study approach. The results show that the importance of science centers goes far beyond their function as tourist attractions, and that regular participation in their programs can enrich the knowledge base of their host city and agglomerations. The study indicates that science centers have all the required tools and methodological experience to effectively support public education in STEM fields. Finally, their ability to adapt quickly to changing circumstances, during the COVID-19 epidemic, demonstrates a “future-oriented” approach and tremendous innovation potential that are inherent in these institutions.

Open Access: Yes

DOI: 10.12700/APH.21.3.2024.3.6

Design of acoustic cavity test apparatus for validation of mid-frequency response of a plate-cavity system

Dániel Feszty Tamas Turcsik Janos Kun

Publication Name: Proceedings of 2020 International Congress on Noise Control Engineering Inter Noise 2020

Publication Date: 2020-08-23

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

The mid-frequency range acoustic response between 400-1000 Hz has gained particular interest in the automotive industry recently. Simulation of this region is challenging due to the non-negligible statistical effects, especially when acoustic trim is applied. In order to be able to investigate the effect of these materials in the presence of an air cavity, this paper describes the design methodology behind the design and manufacturing of two test apparatuses that include an air cavity. The apparatuses were designed to serve as a validation tool for Finite Element Method (FEM) and Statistical Energy Analysis (SEA) simulations, which meant that an optimal size had to be found based on the number of fluid modes in the cavity. Two types of plate-cavity apparatuses have been designed: one with “rigid walls” and one with “soft walls”. In the “rigid wall” cavity, the walls are made out of concrete since these boundary conditions can be perfectly represented in simulations. In the “soft wall” cavity, the walls are made of steel plates and this allows validation of coupling loss simulations between multiple structural subsystems as well as an air cavity. Details of the joining methods, geometries, material selections are elaborated to fully describe the theoretical and practical implications of the designs.

Open Access: Yes

DOI: DOI not available

Effects of Different Longitudinal Bending Stiffness Shoes on Distal Joint Kinematics and Muscular Mechanics in Adolescent amateur Runners

Gusztáv Fekete István Bíró Qiaolin Zhang Hairong Chen

Publication Name: Advances in Transdisciplinary Engineering

Publication Date: 2024-01-01

Volume: 59

Issue: Unknown

Page Range: 472-478

Description:

Research has indicated that modifying shoes' longitudinal bending stiffness (LBS) could potentially influence running biomechanics and performance among amateur runners. Nevertheless, scant attention has been given to adolescent runners in previous studies, leaving the impact of various LBS shoes on distal joint kinematics and muscular mechanics unclear. Given the distinctive musculoskeletal attributes of adolescents, delving into this matter holds significant importance. Thirteen adolescent amateur runners with rear foot strikes were recruited for the study. Each participant performed running tasks along a 10-meter runway at a speed of 3.3±5% m/s while wearing two types of LBS shoes, randomized for each trial. The specific LBS values of the shoes were 2.7 Nm/rad (low) and 8.6 Nm/rad (high). Lower limb joint biomechanical data were collected using a Vicon motion analysis system and AMTI force platform. Lower limb joint kinematics and muscular mechanics were analyzed using Opensim software. Paired t-tests were employed to identify differences in distal joint kinematics and muscular mechanics during stance phases. We found that there was a significant increase in contact time, while the range of motion (ROM) of the metatarsophalangeal (MTP) joint in the sagittal plane significantly decreased in the high LBS shoe condition. Additionally, the impulse of flexor digitorum brevis and flexor hallucis longus significantly increased under the high LBS shoe condition. The results show that high LBS shoes impose a greater load on the distal muscles, potentially elevating the risk of running-related injuries. The low LBS shoes are more suitable for adolescent runners.

Open Access: Yes

DOI: 10.3233/ATDE240582

New data on terrestrial gastropods (Gastropoda: Cyclophoroidea) from mid-Cretaceous Burmese amber, with descriptions of two new species in the genus Euthema (Diplommatinidae)

J. M. Bichain Barna Páll-Gergely Imre Szenti M. Szabó None Kokavecz

Publication Name: Zoosystematica Rossica

Publication Date: 2025-01-01

Volume: 34

Issue: 2

Page Range: 336-353

Description:

Mid-Cretaceous Burmese amber preserves an exceptionally diverse assemblage of operculate land snails. Here, two new diplommatinid species are described: Euthema convexispira Bichain et Páll-Gergely, sp. nov. and Eu. torokzselenszkyi Páll-Gergely et Szabó, sp. nov. Newly found specimens of two previously known species, Hirsuticyclus canaliculatus Yu, 2022 and Cretadiostoma caperatum Yu, Zhuo et Páll-Gergely, 2023, are described and illustrated; the specimen of the former is characterised by a distinctive spiral operculum, while that of the latter provides additional data on the morphology of the aperture and the proportions of the shell whorls. Furthermore, the article reports three specimens that are tentatively attributed here to the species Euthema cf. annae Balashov, 2021 and to the genera Euthema Yu, Wang et Pan, 2018 and Pulchraspira Yu, Salvador et Jarzembowski, 2021.

Open Access: Yes

DOI: 10.31610/ZSR/2025.34.2.336

One-at-a-time sensitivity study of a nonlinear fire truck suspension model

Flóra Hajdu Rajmund Kuti Gyozo Molnárka

Publication Name: Fme Transactions

Publication Date: 2020-01-01

Volume: 48

Issue: 1

Page Range: 90-95

Description:

In this paper the detailed OAT (one-at-a-time) sensitivity analysis of a nonlinear fire truck suspension system is carried out with numerical simulation. As output to measure sensitivity the RMS of acceleration was chosen, which can be calculated with numerical simulations easily. The degree of sensitivity was measured with a sensitivity index and based on it sensitivity Fuzzy-sets were established. The membership of each parameter to the Fuzzy sets is calculated and based on it, it was determined which parameters are the most sensitive. With the presented results it is shown that the proposed method is suitable for testing mathematical models as well.

Open Access: Yes

DOI: 10.5937/fmet2001090H

Soil microarthropods mitigate nitrogen loss and enhance crop yield in residue-amended soils

Norbert Flórián Sándor Attila Pabar Bettina Kelemen Veronika Gergócs-Winkler Tünde Imréné Takács

Publication Name: Agriculture Ecosystems and Environment

Publication Date: 2026-07-01

Volume: 404

Issue: Unknown

Page Range: Unknown

Description:

The application of crop residues is a common agricultural practice used to enhance soil health. However, the use of low-quality crop residues can lead to nitrogen (N) depletion in soil due to microbial immobilisation. This microbial activity is influenced by many factors including residue quality, soil type and interactions with higher trophic levels such as microarthropods. To investigate the processes influencing the effectiveness of crop residue application, we conducted a field mesocosm experiment using barley plants grown in either chernozem or sandy soil. As a second factor, low-quality crop residue was added to half of the mesocosms. All soils were initially defaunated, with half subsequently refaunated. Over a three-month period, we measured barley biomass and N content, soil microbial activity, and soluble and soil N concentrations. Inorganic N dynamics were more pronounced in chernozem soil, while differences in crop yield and plant N content were more evident in sandy soil. Residue addition stimulated microbial activity. Although it did not directly deplete soil nitrate, its negative effects were reflected in reduced crop yield and lower leaf N content. Faunal presence significantly reduced nitrate leaching and increased soil nitrate concentrations in both soil types. Moreover, faunated mesocosms exhibited higher microbial activity and crop yield compared to defaunated ones. These findings highlight the critical role of soil microarthropods in mediating the effects of crop residue on plant performance. Thus, maintaining functional soil faunal communities is essential for improving nitrogen retention and crop productivity in residue-amended agricultural systems.

Open Access: Yes

DOI: 10.1016/j.agee.2026.110332

Rethinking sustainable growth: technological and supply chain drivers of the U.S. production-based ecological footprint

Walton Wider Mohammad Fakhrul Islam Kazi Md Shahadat Hossain Arafat Hossain Md Ekramul Hoque

Publication Name: Resources Conservation and Recycling Advances

Publication Date: 2026-09-01

Volume: 31

Issue: Unknown

Page Range: Unknown

Description:

The United States (U.S.) has one of the highest production-based ecological footprints (EFP) in the world. Consequently, reducing EFP is essential for ensuring ecological balance, protecting the environment, and reducing ecological degradation. However, the comparative analysis on the long-run associations of AI innovation (AIN), high-tech trade capability (HTTC), supply chain efficiency (SCE), information and communication technology investment growth (ICTIG), and GDP growth (GDPG) with EFP regarding the U.S. remains poorly understood. Using the autoregressive distributed lag (ARDL) method, this study shows a comparative analysis of the EFP’s determinants relying on the U.S. national level data from 1990 to 2023. Based on the ARDL findings, while AIN, SCE, and HTTC show statistically significant association with EFP in the long run, ICTIG and GDPG do not exhibit significant empirical association. Among three significant associations, AIN and SCE are associated with reductions in ecological footprint in the long run, indicating that the country has secured technology-driven ecological benefits and operational efficiency enhancement within the production dynamics by emphasizing AI innovation and efficient inventory management. In contrast, HTTC’s positive association represents significant ecological pressure with the high tech-industries technology advancement, driven by scale and rebound effects. All the results remained stable in FMOLS, DOLS, and CCR robustness tests. Besides, Granger causality indicates mixed predictive patterns of these relationships. The comparative analysis among these determinants' long-run associations with EFP significantly contributes to the single country level production-based ecological footprint literature and depicts several valuable empirical insights for policy actions by the federal government.

Open Access: Yes

DOI: 10.1016/j.rcradv.2026.200358

The Effect of Rectangle Shaped Cutouts of Corrugated Paperboard Packages on Compressive Strength of Boxes

Péter Böröcz Lajos Fehér

Publication Name: Advances in Transdisciplinary Engineering

Publication Date: 2024-01-01

Volume: 59

Issue: Unknown

Page Range: 81-87

Description:

Corrugated paperboard boxes are widely used as packaging in logistics processes. Corrugated boxes must have adequate strength to ensure proper protection of the product. In many cases, the product will require cutouts in the side walls of the boxes. These significantly affect the strength behavior of the box which can be determined by measurements and various models. The aim of this study is to determine the compressive strength of corrugated cardboard boxes of different sizes and different rectangle shaped cutouts formed on them. Five different box dimensions and five different cutout rates were investigated. Box compression tests were carried out to obtain the compression force result of the boxes. The results of these measurements were compared with the box compression force estimation formulas. Two types of McKee formula were used for the comparison that are commonly used in industry. The complete and the simplified McKee formulas are the used models in this study. The constant parameters for both McKee formulas was calculated for each cutout rates. For higher cutout ratios the accuracy of both the simplified and the complete McKee formula increases. In three groups at 0%, 4% and 16% cutouts the fitted complete and simplified McKee formulas predict the BCT results with significant differences. It can be observed that neither the complete nor the simplified McKee formula is able to account for changes in compression force due to variations in box size for any cutout category.

Open Access: Yes

DOI: 10.3233/ATDE240530