Instytut Podstawowych Problemów Techniki

Ahmed A., Nuria A., Bethany A., Pierini F., Zargarian S., Interfacing with the Brain: How Nanotechnology Can Contribute, ACS Nano, ISSN: 1936-0851, DOI: 10.1021/acsnano.4c10525, pp.A-CJ, 2025

Abstract:
Interfacing artificial devices with the human brain is the central goal of neurotechnology. Yet, our imaginations are often limited by currently available paradigms and technologies. Suggestions for brain–machine interfaces have changed over time, along with the available technology. Mechanical levers and cable winches were used to move parts of the brain during the mechanical age. Sophisticated electronic wiring and remote control have arisen during the electronic age, ultimately leading to plug-and-play computer interfaces. Nonetheless, our brains are so complex that these visions, until recently, largely remained unreachable dreams. The general problem, thus far, is that most of our technology is mechanically and/or electrically engineered, whereas the brain is a living, dynamic entity. As a result, these worlds are difficult to interface with one another. Nanotechnology, which encompasses engineered solid-state objects and integrated circuits, excels at small length scales of single to a few hundred nanometers and, thus, matches the sizes of biomolecules, biomolecular assemblies, and parts of cells. Consequently, we envision nanomaterials and nanotools as opportunities to interface with the brain in alternative ways. Here, we review the existing literature on the use of nanotechnology in brain–machine interfaces and look forward in discussing perspectives and limitations based on the authors’ expertise across a range of complementary disciplines─from neuroscience, engineering, physics, and chemistry to biology and medicine, computer science and mathematics, and social science and jurisprudence. We focus on nanotechnology but also include information from related fields when useful and complementary.

Kulicki M., Carlos C., Trzciński T., Będkowski J., Stereńczak K., Artificial Intelligence and Terrestrial Point Clouds for Forest Monitoring, Current Forestry Reports, ISSN: 2198-6436, DOI: 10.1007/s40725-024-00234-4, Vol.11, pp.5-1-5-19, 2025

Abstract:
[Purpose of Review:] This paper provides an overview of integrating artificial intelligence (AI), particularly deep learning (DL), with ground-based LiDAR point clouds for forest monitoring. It identifies trends, highlights advancements, and discusses future directions for AI-supported forest monitoring.

[Recent Findings:] Recent studies indicate that DL models significantly outperform traditional machine learning methods in forest inventory tasks using terrestrial LiDAR data. Key advancements have been made in areas such as semantic segmentation, which involves labeling points corresponding to different vegetation structures (e.g., leaves, branches, stems), individual tree segmentation, and species classification. Main challenges include a lack of standardized evaluation metrics, limited code and data sharing, and reproducibility issues. A critical issue is the need for extensive reference data, which hinders the development and evaluation of robust AI models. Solutions such as the creation of large-scale benchmark datasets and the use of synthetic data generation are proposed to address these challenges. Promising AI paradigms like Graph Neural Networks, semi-supervised learning, self-supervised learning, and generative modeling have shown potential but are not yet fully explored in forestry applications.

[Summary:] The review underscores the transformative role of AI, particularly DL, in enhancing the accuracy and efficiency of forest monitoring using ground-based 3D point clouds. To advance the field, there is a critical need for comprehensive benchmark datasets, open-access policies for data and code, and the exploration of novel DL architectures and learning paradigms. These steps are essential for improving research reproducibility, facilitating comparative studies, and unlocking new insights into forest management and conservation.

Keywords:
Deep learning, Machine learning, Forest inventory, Tree characteristics, Open data, Precision forestry, LiDAR, TLS

Kulus D., Tymoszuk A., Gościnna K., Osial M., Enhancing Germination and Growth of Chrysanthemum Synthetic Seeds Through Iron Oxide Nanoparticles and Indole-3-Acetic Acid: Impact of Treatment Duration on Metabolic Activity and Genetic Stability, Nanotechnology, Science and Applications, ISSN: 1177-8903, DOI: 10.2147/NSA.S503868, Vol.18, pp.139-155, 2025

Keywords:
antioxidant capacity, Chrysanthemum × morifolium /Ramat./ Hemsl., molecular markers, nanotechnology, polyphenols, SCoT

Kędziorski P., Skoratko A., Katzer J., Tysiąc P., Jagoda M., Zawidzki M., Harnessing low-cost LiDAR scanners for deformation assessment of 3D-printed concrete-plastic columns with cross-sections based on fractals after critical compressive loading, MEASUREMENT, ISSN: 0263-2241, DOI: 10.1016/j.measurement.2025.117015, Vol.249, pp.1-16, 2025

Abstract:
This article aims to explore the potential of using low-cost devices (iPhone and iPad) equipped with LiDAR scanners in the context of measuring the volume of concrete-plastic specimens with complex shapes. The goal was to assess whether these tools can support or even replace traditional metrology methods. For the purpose of the research program concrete-plastic columns with very complex cross-sections (based on different fractals) were harnessed. The research team was focused on analyzing the potential of using this technology to measure the volume of concrete-plastic structural elements created with the help of 3D printing. The tests were conducted under laboratory conditions. The effectiveness of the proposed approach was compared with results obtained using photogrammetry. The challenges of measurement accuracy, the impact of specimen shape, the impact of material and needed optimization of post-processing on the achieved results were also discussed.

Keywords:
3-D printing, LiDAR, Scanning, Fractals, Concrete

Tytko G., Adamczyk-Habrajska M., Linke Y., Liu Z., Kopeć M., High frequency eddy current method in inspection of aluminide coatings integrity after simulating service loads, MEASUREMENT, ISSN: 0263-2241, DOI: 10.1016/j.measurement.2025.117356, Vol.252, No.117356, pp.1-11, 2025

Abstract:
This study investigates the use of high-frequency eddy current testing (ECT) to assess the structural integrity of aluminide coatings on MAR-M247 nickel superalloy under simulated fatigue conditions. Aluminide coatings, deposited via chemical vapor deposition at thicknesses of 20 µm and 40 µm, were tested using custom-designed probes optimized for defect detection. Results demonstrate that substrate grain structure and coating thickness significantly influence coating durability, with fine-grain substrates exhibiting the least resistance changes and greatest fatigue tolerance. Eddy current signal variations correlated with microstructural changes, enabling detection of damage otherwise invisible to traditional methods. These findings establish ECT as a precise, non-destructive approach for monitoring aluminide coatings in critical applications.

Keywords:
Nickel alloys, Aluminide coating, Non-destructive testing, Eddy current testing

Deshpande S., Rappel H., Hobbs M., Bordas S., Lengiewicz J.A., Gaussian process regression + deep neural network autoencoder for probabilistic surrogate modeling in nonlinear mechanics of solids, COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING, ISSN: 0045-7825, DOI: 10.1016/j.cma.2025.117790, Vol.437, No.117790, pp.1-17, 2025

Abstract:
Many real-world applications demand accurate and fast predictions, as well as reliable uncertainty estimates. However, quantifying uncertainty on high-dimensional predictions is still a severely under-investigated problem, especially when input–output relationships are non-linear. To handle this problem, the present work introduces an innovative approach that combines autoencoder deep neural networks with the probabilistic regression capabilities of Gaussian processes. The autoencoder provides a low-dimensional representation of the solution space, while the Gaussian process is a Bayesian method that provides a probabilistic mapping between the low-dimensional inputs and outputs. We validate the proposed framework for its application to surrogate modeling of non-linear finite element simulations. Our findings highlight that the proposed framework is computationally efficient as well as accurate in predicting non-linear deformations of solid bodies subjected to external forces, all the while providing insightful uncertainty assessments.

Keywords:
Surrogate modeling,Deep neural networks,Gaussian proces,Autoencoders,Uncertainty quantification,Finite element method

Hou J., Xu D., Jankowski Ł., Structural modal parameter identification with the Power-Exponential window function, MECHANICAL SYSTEMS AND SIGNAL PROCESSING, ISSN: 0888-3270, DOI: 10.1016/j.ymssp.2024.111771, Vol.222, pp.111771-1-111771-23, 2025

Abstract:
In view of the demand for accurate modal identification, and based on the characteristics of free vibration response, this paper introduces a new window function for Fourier Transform called the Power–Exponential window. The Power–Exponential window addresses the characteristics of free vibration response. It significantly enhances the accuracy of modal identification by improving the spectral properties of structural response. The proposed window function consists of exponential and power terms. This study focuses on the additional damping and frequency-domain differentiation introduced by the Power–Exponential window function. The exponential term weakens the boundary effect related to the time-domain truncation and suppresses the spectral leakage. Moreover, it can be interpreted in clear physical terms as providing additional damping to the signal. The power term in the window function corresponds to frequency domain differentiation, and it alleviates the spectral broadening that arises due to the additional damping. Furthermore, the analytical expression for the response spectrum confirms that the Power–Exponential window not only aligns the peak response frequency with the damped natural frequency but also establishes an explicit linear relationship between the actual structural damping ratio and the identification result from the half power bandwidth method. Both contribute to an improved accuracy and usability of certain frequency-domain modal identification methods. The influence of the Power–Exponential window parameters on modal parameter identification is analyzed, and the optimal selection principle and suggested parameter values are proposed. Finally, numerical simulations and an experimental frame model test are conducted to verify the accuracy and validity of modal parameter identification based on the Power–Exponential window.

Keywords:
Modal identification, Window function, Frequency domain, Spectrum leakage, Fourier Transform (FT)

Nwaji N., Fikadu B. B., Osial M., Warczak M., Moazzami Goudarzi Z., Gniadek M., Asgaran S., Lee J., Giersig M., Advanced Functional NiCo 2 S4 @CoMo2 S4 Heterojunction Couple as Electrode for Hydrogen Production via Energy-Saving Urea Oxidation, Small, ISSN: 1613-6810, DOI: 10.1002/smll.202410848, Vol.2410848, pp.1-13, 2025

Abstract:
The urea oxidation reaction (UOR) is characterized by a lower overpotential compared to the oxygen evolution reaction (OER) during electrolysis, which facilitates the hydrogen evolution reaction (HER) at the cathode. Charge
distribution, which can be modulated by the introduction of a heterostructure, plays a key role in enhancing the adsorption and cleavage of chemical groups within urea molecules. Herein, a facile all-room temperature synthesis of functional heterojunction NiCo2 S4 /CoMo 2 S4 grown on carbon cloth (CC) is presented, and the as-prepared electrode served as a catalyst for simultaneous hydrogen evolution and urea oxidation reaction. The Density
Functional Theory (DFT) study reveals spontaneous transfer of charge at the heterointerface of NiCo 2 S4 /CoMo 2 S4 , which triggers the formation of localized electrophilic/nucleophilic regions and facilitates the adsorption of electron donating/electron withdrawing group in urea molecules during the UOR. The NiCo2 S4 /CoMo 2 S4 // NiCo 2 S4 /CoMo 2 S4 electrode pair required only a cell voltage of 1.17 and 1.18 V to deliver a current density of 10 and 100 mA cm−2 respectively in urea electrolysis cell and display very good stability. Tests performed in real urine samples show similar catalytic performance to urea electrolytes, making the work one of the best transition
metal-based catalysts for UOR applications, promising both efficient hydrogen production and urea decomposition.

Liu S., Wu J., He S., Yuan X., Stupkiewicz S., Wang Y., Effect of substrate stiffness on interfacial Schallamach wave of flexible film/substrate bilayer structure: Cohesive contact insight, TRIBOLOGY INTERNATIONAL, ISSN: 0301-679X, DOI: 10.1016/j.triboint.2024.110358, Vol.202, pp.110358-1-14, 2025

Abstract:
As the critical feature of the stick-slip for soft materials, the interfacial Schallamach waves of flexible composite structures are essential for smart tactile sensors to realize sliding perception. Herein, the Schallamach waves of polydimethylsiloxane film/substrate bilayer structures with three substrate stiffnesses regulated by porosities are investigated by setting up in-situ sliding tests and establishing finite element models with mixed-mode cohesive contact. Inhomogeneity in microcontact stiffness disrupts the continuity and synchronization of the Schallamach waves, resulting in non-periodic fluctuations in the contact force. The buckling phenomenon of the film structure marks the transition from stick to slip. This buckling induces a shift at the crack front from normal compressive stress to tensile stress, leading to mixed-mode damage.

Keywords:
Stick-slip,Polydimethylsiloxane film/substrate bilayer structures,Schallamach wave,In-situ sliding test,Mixed-mode cohesive contact model

Liu S., Wu J., Teng F., He S., Yuan X., Stupkiewicz S., Wang Y., Effect of surface adhesion characteristics on stick-slip mechanism of flexible film/substrate bilayer structure: Multiscale insight, TRIBOLOGY INTERNATIONAL, ISSN: 0301-679X, DOI: 10.1016/j.triboint.2025.110520, Vol.204, pp.110520-1-16, 2025

Abstract:
The key to tactile sensors' sliding perception is the stick-slip modulation of the soft material through surface design. Herein, in-situ sliding tests were conducted on polydimethylsiloxane (PDMS) film/substrate bilayer structures (PF/SBS) with three surface adhesion characteristics tailored by crosslinking degrees of PDMS film. Microscopic damage mechanisms during Schallamach wave propagation were analyzed using mixed-mode cohesive contact models. Intermolecular interaction mechanisms at microscopic crack tips were also explored using PDMS-Silica (SiO2) molecular models with varying PDMS crosslinking degrees. The Schallamach waves and tangential force strongly depended on the crosslinking degree of PDMS film. The varying effects of crosslinking degree on normal and tangential separation mechanisms lead to a transition in Schallamach wave damage from mixed mode to Mode II during propagation.

Keywords:
Stick-slip,Film/substrate bilayer structures,Cohesive contact model,Intermolecular interaction

Zakrzewska A., Kosik-Kozioł A., Zargarian S., Zanoni M., Gualandi C., Lanzi M., Pierini F., Lemon Juice-Infused PVA Nanofibers for the Development of Sustainable Antioxidant and Antibacterial Electrospun Hydrogel Biomaterials, BIOMACROMOLECULES, ISSN: 1525-7797, DOI: 10.1021/acs.biomac.4c01466, Vol.26, No.1, pp.654-669, 2025

Abstract:
Cross-linking bonds adjacent polymer chains into a three-dimensional network. Cross-linked poly(vinyl alcohol) (PVA) turns into a hydrogel, insoluble structure exhibiting outstanding sorption properties. As an electrospinnable polymer, PVA enables the creation of nanofibrous hydrogels resembling biological tissues, thus ideal for nature-inspired platforms. PVA properties are easily adjustable through additives and an appropriate cross-linking method. Drawing inspiration from environmentally safe approaches, this work developed a new “green” method of low-temperature PVA cross-linking. Nanofibers were electrospun from a precursor solution of PVA dissolved in fresh lemon juice, stabilized by heating at 60 °C for 7 days, and thoroughly characterized. The obtained nanoplatform demonstrated long-term stability and enhanced mechanical properties. Its biocompatibility was confirmed, and its antibacterial and health-promoting effects were attributed to lemon juice-rich in vitamin C, a potent antioxidant with anti-inflammatory properties. The developed system has future potential for use in the biomedical engineering field as a dressing accelerating wound healing.

Postek E. W., Sadowski T., Guhathakurta J., Steel Ball Impact on SiC/AlSi12 Interpenetrated Composite by Peridynamics, Materials, ISSN: 1996-1944, DOI: 10.3390/ma18020290, Vol.18, No.290, pp.1-25, 2025

Abstract:
Silicon carbide and an aluminum alloy (SiC/AlSi12) composite are obtained during the pressurized casting process of the aluminum alloy into the SiC foam. The foam acts as a high-stiffness skeleton that strengthens the aluminum alloy matrix. The goal of the paper is to describe the behavior of the material, considering its internal structure. The composite’s structure is obtained by using X-ray computing tomography. The thorough computer tomography analysis allows for the high-precision identification of the shape and distribution of the pores in the matrix. The computational model prepared in the framework of the peridynamics method takes into account the pores and their shape. The pores in the structure appeared in the fabrication process. The impact of a steel ball is studied employing the peridynamics method. The sample without any porosity and a porous one were considered during the analyses. It has been found that the porosity of the matrix influences the plastic strain development, but the damage parameter in the skeleton is not affected significantly. The damage advancement in the skeleton during the process is practically identical in both cases. The equivalent plastic strain field is much smoother in a non-porous matrix than in a porous one. The porous matrix has high equivalent
plastic strain concentrations, much higher than the non-porous matrix. The shape of the sample is affected by the porosity of the matrix. The sample with a porous matrix tends to fragment, and it shows a tendency towards spallation when in close contact to the surface with the base.

Keywords:
interpenetrated composite, impact, damage, perydynamics

Vafaei E., Hasani M., Salehi N., Sabbagh Mojaveryazdi F., Hasani S., Enhancement of Biopolymer Film Properties Using Spermidine, Zinc Oxide, and Graphene Oxide Nanoparticles: A Study of Physical, Thermal, and Mechanical Characteristics, Materials, ISSN: 1996-1944, DOI: 10.3390/ma18020225, Vol.18, No.2, pp.225-1-17, 2025

Abstract:
One of the main limitations of biopolymers compared to petroleum-based polymers is their weak mechanical and physical properties. Recent improvements focused on surmounting these constraints by integrating nanoparticles into biopolymer films to improve their efficacy. This study aimed to improve the properties of gelatin–chitosan-based biopolymer layers using zinc oxide (ZnO) and graphene oxide (GO) nanoparticles combined with spermidine to enhance their mechanical, physical, and thermal properties. The results show that adding ZnO and GO nanoparticles increased the tensile strength of the layers from 9.203 MPa to 17.787 MPa in films containing graphene oxide and zinc oxide, although the elongation at break decreased. The incorporation of nanoparticles reduced the water vapor permeability from 0.164 to 0.149 (g.m−2.24 h−1). Moreover, the transparency of the layers ranged from 72.67% to 86.17%, decreasing with higher nanoparticle concentrations. The use of nanoparticles enhanced the light-blocking characteristics of the films, making them appropriate for the preservation of light-sensitive food items. The thermal properties improved with an increase in the melting temperature (Tm) up to 115.5 °C and enhanced the thermal stability in the nanoparticle-containing samples. FTIR analysis confirmed the successful integration of all components within the films. In general, the combination of gelatin and chitosan, along with ZnO, GO, and spermidine, significantly enhanced the properties of the layers, making them stronger and more suitable for biodegradable packaging applications.

Keywords:
nanocomposite,gelatin,chitosan,zinc oxide,graphene oxide

Boka Fikadu B., Mahendra G., Nwaji N., Juyoung G., Gicha B., Hyojin K., Asgaran S., Hee-Joon C., Lee J., Defect Engineered Ru-CoMOF@MoS2 HeterointerfaceFacilitate Water Oxidation Process, Chemistry Europe, ISSN: 1864-564X, DOI: 10.1002/cssc.202402533, pp.1-12, 2025

Abstract:
Catalyst design plays a critical role in ensuring sustainable andeffective energy conversion. Electrocatalytic materials need tobe able to control active sites and introduce defects in bothacidic and alkaline electrolytes. Furthermore, producing efficientcatalysts with a distinct surface structure advances ourcomprehension of the mechanism. Here, a defect-engineeredheterointerface of ruthenium doped cobalt metal organic frame(Ru-CoMOF) core confined in MoS2 is reported. A tailored designapproach at room temperature was used to induce defects andform an electron transfer interface that enhanced the electro-catalytic performance. The Ru-CoMOF@MoS2 heterointerfaceobtains a geometrical current density of 10 mA-2 by providinghydrogen evolution reaction (HER) and oxygen evolutionreaction (OER) at small overpotentials of 240 and 289 mV,respectively. Density functional theory simulation shows thatthe Co-site maximizes the evolution of hydrogen intermediateenergy for adsorption and enhances HER, while the Ru-site, onthe other hand, is where OER happens. The heterointerfaceprovides a channel for electron transfer and promotes reactionsat the solid-liquid interface. The Ru-CoMOF@MoS2 modelexhibits improved OER and HER efficiency, indicating that itcould be a valuable material for the production of water-alkaline and acidic catalysts

Zargarian S., Salvio S., Javier S., Zuppiroli L., Lanzi M., Ruiz-Molina D., Pierini F., Light-Activated Superhydrophobicity of Sustainable Micro-Structured Spent Coffee Grounds-Based Interfaces via Fatty Acids Modulation, ChemSusChem, ISSN: 1864-5631, DOI: 10.1002/cssc.202402254, pp.e202402254-1-14, 2025

Abstract:
The global consumption of coffee results in the disposal of vast amounts of spent coffee grounds (SCG), posing significant environmental challenges. Herein, we address this issue by developing an innovative, eco-friendly method to achieve superhydrophobicity using SCG. Repurposing this abundant biowaste, we developed a sustainable approach that avoids the use of harsh chemicals and energy-intensive processes typically associated with conventional methods. Our procedure involves wet ball milling of SCG in ethanol to produce microparticles, followed by electrospraying to create a micro-structured interface. A mild annealing treatment at 90 °C successfully transformed the SCG interface from hydrophilic to superhydrophobic, reaching a contact angle of approximately 151° and a rolling-off angle of 8°. The resultant interface exhibited remarkable self-cleaning properties, effectively repelling various liquids. XPS analysis revealed that the migration of fatty acids to the surface during annealing played a crucial role in lowering surface energy, thereby driving the hydrophilic-to-superhydrophobic transition. Furthermore, we demonstrated that solar-induced heating can effectively activate the same superhydrophobic properties, providing a practical and energy-efficient alternative to traditional thermal treatments. This method illustrates the role of light-activated fatty acid modulation in achieving superhydrophobicity and highlights the potential of SCG biowaste as a valuable resource for sustainable material applications.

Rabcuka J., Smethurst P. A., Dammert K., Saker J., Aran G., Walsh G. M., Tan J. C. G., Codinach M., McTaggart K., Marks D. C., Bakker S. J. L., McMahon A., Di Angelantonio E., Roberts D. J., Błoński S., Korczyk P.M., Shirakami A., Cardigan R., Swietach P., Assessing the kinetics of oxygen-unloading from red cells using FlowScore, a flow-cytometric proxy of the functional quality of blood, eBioMedicine, ISSN: 2352-3964, DOI: 10.1016/j.ebiom.2024.105498, Vol.111, pp.105498-105498, 2025

Abstract:
Background
Metrics evaluating the functional quality of red blood cells (RBCs) must consider their role in oxygen delivery. Whereas oxygen-carrying capacity is routinely reported using haemoglobin assays, the rate of oxygen exchange is not measured, yet also important for tissue oxygenation. Since oxygen-unloading depends on the diffusion pathlength inside RBCs, cell geometry offers a plausible surrogate.
Methods
We related the time-constant of oxygen-unloading (τ), measured using single-cell oxygen saturation imaging, with flow-cytometric variables recorded on a haematology analyser. Experiments compared freshly-drawn RBCs with stored RBCs, wherein metabolic run-down and spherical remodelling hinder oxygen unloading.
Findings
Multivariable regression related τ to a ratio of side- and forward-scatter, referred to herein as FlowScore. FlowScore was able to distinguish, with sensitivity and specificity >80%, freshly drawn blood from blood that underwent storage-related kinetic attrition in O2-handling. Moreover, FlowScore predicted τ restoration upon biochemical rejuvenation of stored blood. Since RBC geometry and metabolic state are related, variants of FlowScore estimated [ATP] and [2,3-diphosphoglycerate]. The veracity of FlowScore was confirmed by four blood-banking systems (Australia, Canada, England, Spain). Applying FlowScore to data from the COMPARE study revealed a positive association with the time-delay from sample collection to measurement, which was verified experimentally. The LifeLines dataset revealed age, sex, and smoking among factors affecting FlowScore.
Interpretation
We establish FlowScore as a widely-accessible and cost-effective surrogate of RBC oxygen-unloading kinetics. As a metric of a cellular process that is sensitive to storage and disease, we propose FlowScore as an RBC quality marker for blood-banking and haematology.

Keywords:
Haematology,Erythrocytes,Storage lesion,Assay,Oxygen transport,Transfusion

Brachaczek A., Tokpatayeva R., Olek J., Jarząbek D.M., Piotrowski P., Jenczyk P., Jóźwiak-Niedźwiedzka D., Impact of formate based deicing agents on ASR products: Microstructural, chemical and mechanical characteristics, CONSTRUCTION AND BUILDING MATERIALS, ISSN: 0950-0618, DOI: 10.1016/j.conbuildmat.2025.140729, Vol.471, No.140729, pp.1-12, 2025

Abstract:
This study investigates the effects of formate-based deicing agents, specifically potassium formate (HCOOK) and sodium formate (HCOONa), on alkali-silica reaction (ASR) in concrete. By adapting ASTM C1260 standards, mortar bars were subjected to deicing solutions of varying concentrations to evaluate their influence on mortar expansion and ASR product characteristics. Results revealed that high concentrations of formate solutions significantly accelerated ASR, inducing expansions comparable to or greater than those caused by sodium hydroxide, while sodium chloride showed minimal expansion effects. Microstructural and chemical analyses demonstrated that ASR gels formed in formate solutions were predominantly amorphous, with different chemical composition depending on the deicer type. Pore solution analysis indicated a strong correlation between alkali ion concentration and mortar expansion. Furthermore, mechanical testing of ASR products revealed that gels formed in potassium formate exhibited higher hardness and elastic modulus compared to those formed in sodium formate. These findings enhance understanding of the detrimental effects of formate-based deicing agents on ASR and provide a foundation for developing mitigation strategies to preserve concrete infrastructure.

Keywords:
Alkali-silica reaction,Concrete microstructure,Expansion,Nanoindentation,Deicing agents,Pore solution analysis

Fathalian M., Darban H., Postek E. W., Atomistic insights into tensile damage of functionally Graded Al-SiC composites, INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, ISSN: 0020-7403, DOI: 10.1016/j.ijmecsci.2025.110012, Vol.288, pp.110012-1-110012-16, 2025

Abstract:
The tensile behavior and damage mechanisms of functionally graded (FG) Al-SiC composites are systematically investigated using molecular dynamics (MD) simulations. A comprehensive set of large-scale MD simulations is conducted on FG composites composed of three layers reinforced with different volume fractions of randomly distributed three-dimensional SiC particles. This work introduces a novel approach by modeling the reinforcement ceramic as three-dimensional particles, thereby more accurately representing the FG composite microstructure. Predictions of the model for Young's moduli of composites align with experimental data from the literature. The yield and ultimate tensile strength are overestimated due to the high applied strain rates and idealized crystal structures used in the simulations, which lack common defects such as vacancies and dislocations. The model is utilized to study the influence of reinforcement particle shape, size, orientation, and distribution on the tensile and damage behavior of composites. The FG composites reinforced with cubic particles demonstrate lower yield and tensile strength than those with spherical particles, primarily due to the high-stress concentrations around the corners of the cubic reinforcements. Reducing the size of SiC particles enhances the elastic modulus, yield, and tensile strength of the FG composites. It is shown that the stiffness of the FG composites reinforced with rectangular prisms can be effectively tailored by changing the orientation of the reinforcements. When SiC rectangular prisms are aligned along the tensile direction, the resulting FG composites exhibit higher yield and tensile strength. This work offers fundamental atomistic insights that help design FG composites with better mechanical performance.

Pruchniewski M., Strojny-Cieślak B., Nakielski P., Zawadzka K., Urbańska K., Rybak D., Zakrzewska A., Grodzik M., Sawosz E., Electrospun poly-(L-lactide) scaffold enriched with GO-AuNPs nanocomposite stimulates skin tissue reconstruction via enhanced cell adhesion and controlled growth factors release, MATERIALS AND DESIGN, ISSN: 0264-1275, DOI: 10.1016/j.matdes.2025.113713, Vol.251, pp.113713-1-18, 2025

Abstract:
The disruption of homeostasis in the tissue microenvironment following skin injury necessitates the provision of a supportive niche for cells to facilitate the restoration of functional tissue. A meticulously engineered cell-scaffold biointerface is essential for eliciting the desired cellular responses that underpin therapeutic efficacy. To address this, we fabricated an electrospun poly-(L-lactide) (PLLA) cell scaffold enriched with graphene oxide (GO) and gold nanoparticles (AuNPs). Comprehensive characterization assessed the scaffolds’ microstructural, elemental, thermal, and mechanical properties. In vitro investigations evaluated the biocompatibility, adhesive and regenerative capabilities of the scaffolds utilizing human keratinocytes (HEKa), fibroblasts (HFFF2), and reconstructed epidermis (EpiDerm™) models. The results demonstrated that the incorporation of the GO-Au composite substantially altered the nanotopography and mechanical properties of the PLLA fibers. Cells effectively colonized the PLLA + GO-Au scaffold while preserving their structural morphology. Furthermore, PLLA + GO-Au treatment resulted in increased epidermal thickness and reduced tissue porosity. The scaffold exerted a significant influence on actin cytoskeleton architecture, facilitating cell adhesion through the upregulation of integrins, E-cadherin, and β-catenin. Keratinocytes exhibited enhanced secretion of growth factors (AREG, bFGF, EGF, EGF R), while fibroblast secretion remained stable. These findings endorse the scaffold’s potential for regulating cellular fate and preventing hypertrophic tissue formation in skin tissue engineering.

Keywords:
Wound healing,Electrospun fibers,Graphene oxide,Gold nanoparticles,Proregenerative cell scaffold

Zaszczyńska A., Marzena Z., Kołbuk-Konieczny D., Denis P., Gradys A., Sajkiewicz P., On the Structural and Biological Effects of Hydroxyapatite and Gold Nano-Scale Particles in Poly(Vinylidene Fluoride) Smart Scaffolds for Bone and Neural Tissue Engineering, Molecules, ISSN: 1420-3049, DOI: 10.3390/molecules30051041, Vol.30, No.5, pp.1041-1-32, 2025

Abstract:
Piezoelectric materials, due to their ability to generate an electric charge in response to mechanical deformation, are becoming increasingly attractive in the engineering of bone and neural tissues. This manuscript reports the effects of the addition of nanohydroxyapatite (nHA), introduction of gold nanoparticles (AuNPs) via sonochemical coating, and collector rotation speed on the formation of electroactive phases and biological properties in electrospun nanofiber scaffolds consisting of poly(vinylidene fluoride) (PVDF). FTIR, WAXS, DSC, and SEM results indicate that introduction of nHA increases the content of electroactive phases and fiber alignment. The collector rotational speed increases not only the fiber alignment but also the content of electroactive phases in PVDF and PVDF/nHA fibers. Increased fiber orientation and introduction of each of additives resulted in increased SFE and water uptake. In vitro tests conducted on MG-63 and hiPSC-NSC cells showed increased adhesion and cell proliferation. The results indicate that PVDF-based composites with nHA and AuNPs are promising candidates for the development of advanced scaffolds for bone and neural tissue engineering applications, combining electrical functionality and biological activity to support tissue regeneration.

Keywords:
scaffolds, tissue engineering, bone tissue engineering, smart medicine, biodegradable polymers, regenerative medicine, poly(vinylidene fluoride)

Jóźwiak-Niedźwiedzka D., Rovnanik P., Dąbrowski M., Ośko J., Kuć M., Maciak M., Gamma radiation attenuation, mechanical properties and microstructure of barite-modified cement and geopolymer mortars, Nuclear Engineering and Technology, ISSN: 1738-5733, DOI: 10.1016/j.net.2024.10.057, Vol.57 (4), No.103295, pp.1-11, 2025

Abstract:
The present study contributes to the development of alternative materials for radiation shielding, focusing on environmental sustainability and material cost efficiency. The primary aim was to evaluate the compressive and flexural strength, mineral composition, microstructure, and gamma-ray attenuation properties of cement mortars and geopolymer mortars containing barite powder. Mortars based on ordinary Portland cement (OPC) and fly ash geopolymers with varying amounts of barite powder were assessed for their shielding properties at energy levels associated with the decay of 137Cs. From the results, key parameters such as the linear attenuation coefficient (μ), mass attenuation coefficient (μm), half-value layer (HVL), and tenth-value layer (TVL) were determined. The results showed that while cement-based composites exhibited superior gamma radiation attenuation compared to fly ash geopolymer mortars, the latter had higher mass attenuation efficiency, meaning less material density was required for the same level of shielding. Additionally, cement mortars had 23–25 % higher mechanical strength than geopolymer mortars. Importantly, the inclusion of barite powder improved the radiation shielding performance of both materials by 7–10 %, demonstrating its effectiveness in enhancing the protective properties of these mortars. This research highlights the potential of fly ash geopolymer mortars as viable, eco-friendly alternatives to traditional cement mortars in radiation shielding applications.

Keywords:
Cement mortar, Fly ash geopolymer mortar, Barite, Gamma ray attenuation, Microstructure

Olaszek P., Świercz A., Ireneusz W., Kołakowski P.D., Monitoring and Numerical Analyses of the Steel Railway Arch Bridge: A Case Study, Journal of Bridge Engineering, ISSN: 1084-0702, DOI: 10.1061/JBENF2.BEENG-6962, Vol.30, No.1, pp.05024007-1-05024007-16, 2025

Abstract:
The subject of research is a steel arch-tied bridge at a high-speed railway line in Poland. After the construction was completed, a resonance phenomenon was observed at the bridge, consisting of the occurrence of intense (visible to the unaided eye) undamped vibrations of some vertical hangers in the horizontal direction, transverse to the track axis. These vibrations occurred without the presence of a railway load on the bridge. Before the bridge was put into operation, an acceptance static and dynamic load test was performed, and then the bridge deck vibrations were monitored for a year. The research during dynamic loads testing included both quasi-static (10 km/h) and high-speed (200 km/h) testing train passages. The vertical displacement measurements were carried out in three cross sections of the span, and the acceleration of vibrations on girders and selected hangers was also measured. Next, an innovative system for determining displacements indirectly using inertial sensors (inclinometers and accelerometers) was used for bridge deck vibration monitoring. The primary aim of the research was to investigate the possibility of assessing the safe operation of the bridge using a monitoring system consisting of a limited number of inertial sensors. The second aim was to verify the feasibility of calibrating the numerical model based on the results of dynamic load testing. Numerical analyses of the behavior of the bridge during the passage of trains with speeds up to 200 km/h were carried out. The developed and calibrated numerical model provides additional information about the overall structural vibrations, facilitating the interpretation of outcomes of the monitoring system. No significant impact of hanger vibrations on the monitored displacements and accelerations of the bridge deck vibrations during the passage of trains was found.

Keywords:
Arch-tied railway bridge,Bridge monitoring,Load testing,Bridge vibration,Numerical model calibration

Kamiński J., Adamczyk-Cieślak B., Kopeć M., Kosiński A., Sitek R., Cover Picture: Materials and Corrosion. 3/2025: Effects of Reduction-Oxidation Cycles on the Structure, Heat and Corrosion Resistance of Haynes 282 Nickel Alloy Manufactured by using Powder Bed Fusion- Laser Beam Method, materials and corrosion, ISSN: 0947-5117, DOI: 10.1002/maco.202570031, pp.1-1, 2025

Keywords:
corrosion, DMLS, haynes 282, nickel superalloy, hydrogen , oxidation

Maździarz M., Suitability of Available Interatomic Potentials for Sn to Model Its 2D Allotropes, Journal of Computational Chemistry, ISSN: 0192-8651, DOI: 10.1002/jcc.70032, Vol.46, No.2, pp.e70032-1-e70032-12, 2025

Abstract:
The suitability of a range of interatomic potentials for elemental tin was evaluated in order to identify an appropriate potential for modeling the stanene (2D tin) allotropes. Structural and mechanical features of the flat (F), low-buckled (LB), high-buckled (HB), full dumbbell (FD), trigonal dumbbell (TD), honeycomb dumbbell (HD), and large honeycomb dumbbell (LHD) monolayer tin (stanene) phases, were gained by means of the density functional theory (DFT) and molecular statics (MS) calculations with ten different Tersoff, modified embedded atom method (MEAM), and machine-learning-based (ML-IAP) interatomic potentials. A systematic quantitative comparison and discussion of the results is reported.

Keywords:
2D materials, DFT, interatomic potentials

Olivos Ramirez G., Cofas Vargas L. F., Tobias M., Poma Bernaola A. M., Conformational and Stability Analysis of SARS-CoV-2 Spike Protein Variants by Molecular Simulation, Pathogens, ISSN: 2076-0817, DOI: 10.3390/pathogens14030274, Vol.14, No.274, pp.1-19, 2025

Abstract:
We performed a comprehensive structural analysis of the conformational space of several spike (S) protein variants using molecular dynamics (MD) simulations. Specifically, we examined four well-known variants (Delta, BA.1, XBB.1.5, and JN.1) alongside the wild-type (WT) form of SARS-CoV-2. The conformational states of each variant were characterized by analyzing their distributions within a selected space of collective variables (CVs), such as inter-domain distances between the receptor-binding domain (RBD) and the N-terminal domain (NTD). Our primary focus was to identify conformational states relevant to potential structural transitions and to determine the set of native contacts (NCs) that stabilize these conformations. The results reveal that genetically more distant variants, such as XBB.1.5, BA.1, and JN.1, tend to adopt more compact conformational states compared to the WT. Additionally, these variants exhibit novel NC profiles, characterized by an increased number of specific contacts distributed among ionic, polar, and nonpolar residues. We further analyzed the impact of specific mutations, including T478K, N500Y, and Y504H. These mutations not only enhance interactions with the human host receptor but also alter inter-chain stability by introducing additional NCs compared to the WT. Consequently, these mutations may influence the accessibility of certain protein regions to neutralizing antibodies. Overall, these findings contribute to a deeper understanding of the structural and functional variations among S protein variants.

Keywords:
Molecular Dynamics, Conformational space, Native contact map, Probability states, Collective variables, Protein stability, SARS-CoV-2

Entezari E., Singh A., Mousavisogolitappeh H., Velazquez J., Szpunar J., A cost-effective model for synergistic effects of microstructure and crystallographic texture on hydrogen-induced crack growth and corrosion rates in pipeline steels, Materials Characterization, ISSN: 1044-5803, DOI: 10.1016/j.matchar.2025.114917, Vol.223, No.114917, pp.1-23, 2025

Abstract:
his study proposes a Cost-Effective model based on microstructure, crystallographic texture, and hydrogen (H) diffusion to evaluate H-damage in pipeline steels. H-crack growth and corrosion rates, measured using ultrasonic inspection and a Gamry electrochemical setup, were correlated with microstructure and texture. Results show that smaller ferrite grain size, lower density of co-incidence site lattice boundaries (CSLB), higher densities of geometrically necessary boundaries (GNB) and random high-angle grain boundaries (RHAGB), and higher overall stored energy (EAve) in texture fibers increase H-trap sites and reduce effective H-diffusivity, contributing to higher H-crack growth rates. Conversely, these same factors enhance corrosion resistance by improving passivation. Secondary phases have a detrimental effect on H-crack growth and corrosion resistance, varying with size, continuity, and volume fraction of phases. The proposed model, using hyperparameter tuning, quantifies the synergistic effects of microstructure, texture, and H-diffusion on H-damage and highlights the role of ferrite grain size in mitigating H-damage in pipeline steels. Finally, finite element (FE) analysis of grain structures provided supporting observations.

Keywords:
H-crack growth rate, Corrosion rate, Microstructure, Crystallographic texture, Cost- effective model, Finite element stress analysis

Markovskyi A., Rosiak M., Vitalii G., Fedorov A., Ciezko M., Szczepański Z., Yuriy Z., Kaczmarek M., Litniewski J., Pakuła M., Acoustic microscopy study on elasto-mechanical properties of Lu 3 Al 5 O 12 :Ce single crystalline films, CrystEngComm , ISSN: 1466-8033, DOI: 10.1039/D5CE00068H, pp.1-13, 2025

Abstract:
This article presents experimental, theoretical, and numerical studies of the propagation of guided ultrasonic waves in a layered epitaxial structure of garnet compounds. A microscopic model, which yields dispersion equations based on material and geometrical properties, is developed. Acoustic microscopy experiments on a YAG:Ce crystal substrate and an epitaxial structure containing LuAG:Ce single crystalline films, grown using the liquid phase epitaxy growth method onto a YAG:Ce crystal substrate, reveal distinct phase velocity behaviors. The YAG substrate exhibits consistent velocities, minimally influenced by frequency, while the epitaxial structure shows dispersion, indicating frequency-dependent phase velocities. Experimental results are compared with numerically calculated dispersion curves, showing high agreement in the low-frequency range and minor deviations at higher frequencies. An optimization procedure is developed and applied, starting with the YAG substrate and extending to the LuAG:Ce film/YAG:Ce crystal epitaxial structure. The procedure allows for the extraction of material properties, offering valuable insights into the mechanical characteristics of the all-solid-state LuAG:Ce film/YAG:Ce crystal structure. This research represents a significant advancement in understanding ultrasonic wave dynamics in layered structures, particularly unveiling previously unexplored elastic properties of LuAG:Ce single crystalline films as a well-known scintillation material.

Nabavian Kalat M., Ziai Y., Dziedzic K., Gradys A. D., Urbański L., Zaszczyńska A., Andrés Díaz L., Kowalewski Z. L., Experimental evaluation of build orientation effects on the microstructure, thermal, mechanical, and shape memory properties of SLA 3D-printed epoxy resin, EUROPEAN POLYMER JOURNAL, ISSN: 0014-3057, DOI: 10.1016/j.eurpolymj.2025.113829, Vol.228, pp.113829-1-18, 2025

Abstract:
Additive manufacturing (AM) methods, popularly known as 3D printing technologies, particularly the pioneering laser stereolithography (SLA), have revolutionized the production of complex polymeric components. However, challenges such as anisotropy, resulting from the layer-by-layer construction method, can affect the thermomechanical properties and dimensional stability of 3D-printed objects. Although anisotropy in SLA 3D printing is often overlooked due to the high precision of this technique, its impact on the properties and structural performance of the 3D-printed prototype becomes more significant when printing small devices designed for precise micro-mechanisms. This experimental study investigates the impact of the chosen printing surface – a less explored factor – on the performance of SLA 4D-printed thermo-responsive shape memory epoxy (SMEp) specimens. Two identical dog-bone specimens were printed from two distinct surfaces: edge and flat surface, to examine how variations in surface area and quantity of layers influence the microstructure, thermal behavior, mechanical properties, and shape memory performance. The results of this experimental investigation reveal that specimens printed from the edge, with a higher number of layers and smaller surface area, exhibit superior interlayer bonding, tensile strength, dimensional stability, and shape recovery efficiency compared to those printed from the flat surface. Conversely, specimens with fewer, larger layers demonstrated greater elongation and thermal expansion but reduced structural integrity and shape recovery performance. These results highlight the importance of experimentally investigating how different build orientations affect the properties and performance of SLA 3D-printed materials, especially before designing and employing them in applications demanding high precision and reliability.

Keywords:
Additive manufacturing, Laser stereolithography, Shape memory polymers, Materials processing, Anisotropy, Printing orientation

Piotrzkowska-Wróblewska H. E., Bajkowski J. M., Dyniewicz B., Bajer C. I., Identification of a spatially distributed diffusion model for simulation of temporal cellular growth, JOURNAL OF BIOMECHANICS, ISSN: 0021-9290, DOI: 10.1016/j.jbiomech.2025.112581, Vol.182, pp.1-7, 2025

Abstract:
This study introduces a spatially distributed diffusion model based on a Navier–Stokes formulation with a pseudo-velocity field, providing a framework for modelling cellular growth dynamics within diseased tissues. Five coupled partial differential equations describe diseased cell development within a two-dimensional spatial domain over time. A pseudo-velocity field mimics biomarker concentration increasing over time and space, influencing tumour growth dynamics. An

Keywords:
Tumour growth, Cellular growth, Cancer, Navier–stokes, Diffusion, Finite element method

Zaszczyńska A., Gradys A. D., Kołbuk-Konieczny D., Zabielski K., Szewczyk P., Stachewicz U., Sajkiewicz P. Ł., Poly(L-lactide)/nano-hydroxyapatite piezoelectric scaffolds for tissue engineering, Micron, ISSN: 0968-4328, DOI: 10.1016/j.micron.2024.103743, Vol.188, pp.103743-1-15, 2025

Abstract:
The development of bone tissue engineering, a field with significant potential, requires a biomaterial with high bioactivity. The aim of this manuscript was to fabricate a nanofibrous poly(L-lactide) (PLLA) scaffold containing nano-hydroxyapatite (nHA) to investigate PLLA/nHA composites, particularly the effect of fiber arrangement and the addition of nHA on the piezoelectric phases and piezoelectricity of PLLA samples. In this study, we evaluated the effect of nHA particles on a PLLA-based electrospun scaffold with random and aligned fiber orientations. The addition of nHA increased the surface free energy of PLLA/nHA (42.9 mN/m) compared to PLLA (33.1 mN/m) in the case of aligned fibers. WAXS results indicated that at room temperature, all the fibers are in an amorphous state indicated by a lack of diffraction peaks and amorphous halo. DSC analysis showed that all samples located in the amorphous/disordered alpha' phase crystallize intensively at temperatures just above the Tg and recrystallize on further heating, achieving significantly higher crystallinity for pure PLLA than for doped nHA, 70 % vs 40 %, respectively. Additionally, PLLA/nHA fibers show a lower heat capacity for PLLA in the amorphous state, indicating that nHA reduces the molecular mobility of PLLA. Moreover, piezoelectric constant d33 was found to increase with the addition of nHA and for the aligned orientation of the fibers. In vitro tests confirmed that the addition of nHA and the aligned orientation of nanofibers increased osteoblast proliferation.

Keywords:
Scaffolds, Tissue engineering, Bone tissue engineering, Smart medicine, Biodegradable polymers, Regenerative medicine

Sitek R., Bochenek K., Maj P., Marczak M., Żaba K., Kopeć M., Kaczmarczyk G., Kamiński J., Hot-Pressing of Ti-Al-N Multiphase Composite: Microstructure and Properties, Applied Sciences, ISSN: 2076-3417, DOI: 10.3390/app15031341, Vol.15, No.1341, pp.1-15, 2025

Abstract:
This study focuses on the development and characterization of a bulk Ti-Al-N
multiphase composite enriched with BN addition and sintered through hot pressing. The
research aimed to create a material with optimized mechanical and corrosion-resistant
properties suitable for demanding industrial applications. The composite was synthesized using a powder metallurgy approach with a mixture of AlN, TiN, and BN powders, processed under a high temperature and pressure. Comprehensive analyses, including microstructural evaluation, hardness testing, X-ray tomography, and electrochemical corrosion assessments, were conducted. The results confirmed the formation of a multiphase microstructure consisting of TiN, Ti₂AlN and Ti₃AlN phases. The microstructure was uniform with minimal porosity, achieving a hardness within the range of 500–540 HV2. Electrochemical tests revealed the formation of a passive oxide layer that provided moderate corrosion resistance in chloride-rich environment. However, localized pitting corrosion was observed under extreme conditions. The study highlights the potential of a BN admixture to enhance mechanical and corrosion-resistant properties and suggests directions for further optimization in sintering processes and material formulations.

Keywords:
AlN-TiN(BN) composite,hot-pressing,μCT,corrosion resistance

Bernard T., Mikułowski G., Szara T., Dołasiński M., Jasiński T., Domino M., Aspect-related mechanical properties of the cortical bone in the third metacarpal bone of mares, Applied Sciences, ISSN: 2076-3417, DOI: 10.3390/app15031593, Vol.15, No.1593, pp.---, 2025

Abstract:
Complete fractures of the third metacarpal bone (MC III) diaphysis pose a significant
clinical challenge, prompting advanced veterinary medicine to utilize constitutive and
biomechanical modeling to better understand bone behavior. This study aims to compare
the elastic modulus of the MC III cortical bone, supported by measurements of cortical
bone thickness and relative density, across the dorsal, lateral, medial, and palmar aspects of
the MC III, as well as to evaluate the cortical bone’s response to compressive forces applied
in different directions. Given the bone structure can exhibit sex-related differences, MC III
bones were isolated from six equine cadaver limbs collected exclusively from mares and
imaged using computed tomography (CT) to measure thickness and density. Cortical bone
samples were collected from the four aspects of the MC III and subjected to mechanical
testing followed by the elastic modulus calculation. Bone thickness and elastic modulus
varied across the MC III aspects. Thinner cortical bone on the palmar aspect coincided with
a lower sample reaction force-based elastic modulus in the externo-internal direction and a
lower axial compression force elastic modulus in the proximo-distal direction. Regardless
of the MC III aspect, the cortical bone demonstrated greater resistance to compressive forces
when loaded in the vertical plane than in the horizontal plane. The returning of different
values in mechanical tests depending on the direction of loading may be attributed to
the anisotropic behavior of the cortical bone, which may implicate the increased risk of
complete fractures of the MC III diaphysis due to a kick from another horse or a fall, rather
than from training or competition-related overload.

Keywords:
bone thickness, mechanical test, copression, bending, elastic modulus, equine

Dyniewicz B., Shillor M., Bajer C. I., Dynamic behavior of an extended Gao beam model including shear deformation, Nonlinear Analysis: Real World Applications, ISSN: 1468-1218, DOI: 10.1016/j.nonrwa.2025.104340, Vol.85, pp.1-14, 2025

Abstract:
This study develops a model of the dynamics of the extended 2D Gao beam and simulates it. Here, the static model studied by Dyniewicz, Shillor and Bajer (Meccanica, 2024), is modified by incorporating inertial terms to account for dynamic behavior. The beam model expands the 1D Gao beam, which can oscillate around a buckled position, and the Timoshenko beam, which factors in shear effects in the beam’s cross sections. The resulting model consists of two highly nonlinear wave equations, alongside specified initial and boundary conditions. A finite element method (FEM) algorithm is created and executed to analyze the system’s vibrations induced by a periodically oscillating longitudinal compressive force. The simulation results are discussed, highlighting the ways the initial conditions influence the solutions, which are graphically illustrated through phase portraits. From an engineering viewpoint, this thick Gao beam model is notable for its relative simplicity. Similarly to the Timoshenko beam model, it includes shear effects, yielding a wave-like equation of motion. Considerations of the shear are essential for accurately analyzing thicker beams, as traditional models that overlook them may fail to capture the true system behaviors. Consequently, this extended Gao model offers more realistic outcomes in dynamic scenarios.

Keywords:
Extended Gao beam, Dynamic oscillations, Vibrations about buckled state, Simulations

Rosowska J., Kaszewski J., Krajewski M., Małolepszy A., Witkowski B. S., Wachnicki Ł., Lev-Ivan B., Sybilski P., Godlewski M., Godlewski M., Growth of ZnO Nanoparticles Using Microwave Hydrothermal Method — Search for Defect-Free Particles, Nanomaterials, ISSN: 2079-4991, DOI: 10.3390/nano15030230, Vol.15, No.230, pp.1-21, 2025

Keywords:
zinc oxide (ZnO) nanoparticles, microwave hydrothermal method , microwave-assisted synthesis, near-band-edge (NBE) emission, deep-level emission (DLE), luminescent properties of ZnO, photoluminescence (PL), cathodoluminescence (CL), defect-related luminescence

Szczęsny G., Kopeć M., Kowalewski Z. L., Toxicity, Irritation, and Allergy of Metal Implants: Historical Perspective and Modern Solutions, Coatings, ISSN: 2079-6412, DOI: 10.3390/coatings15030361, Vol.15, No.361, pp.1-32, 2025

Abstract:
The widespread adoption of metal implants in orthopaedics and dentistry has revolutionized medical treatments, but concerns remain regarding their biocompatibility, toxicity, and immunogenicity. This study conducts a comprehensive literature review of traditional biomaterials used in orthopaedic surgery and traumatology, with a particular focus on their historical development and biological interactions. Research articles were gathered from PubMed andWeb of Science databases using keyword combinations such as “toxicity, irritation, allergy, biomaterials, corrosion, implants, orthopaedic surgery, biocompatible materials, steel, alloys, material properties, applications, implantology, and surface modification”. An initial pool of 400 articles was screened by independent reviewers based on predefined inclusion and exclusion criteria, resulting in 160 relevant articles covering research from 1950 to 2025. This paper explores the electrochemical processes of metals like iron, titanium, aluminium, cobalt, molybdenum, nickel, and chromium post-implantation, which cause ion release and wear debris formation. These metal ions interact with biological molecules, triggering localized irritation, inflammatory responses, and immune-mediated hypersensitivity. Unlike existing reviews, this paper highlights how metal–protein interactions can form antigenic complexes, contributing to delayed hypersensitivity and complications such as peri-implant osteolysis and implant failure. While titanium is traditionally considered bioinert, emerging evidence suggests that under certain conditions, even inert metals can induce adverse biological effects. Furthermore, this review emphasizes the role of oxidative stress, illustrating how metal ion release and systemic toxicity contribute to long-term health risks. It also uncovers the underappreciated genotoxic and cytotoxic effects of metal ions on cellular metabolism, shedding light on potential long-term repercussions. By integrating a rigorous methodological approach with an in-depth exploration of metal-induced biological responses, this paper offers a more nuanced perspective on the complex interplay between metal implants and human biology, advancing the discourse on implant safety and material innovation.

Keywords:
orthopaedic implants, toxicity, metals, biomaterials

Haghighat Bayan M., Kosik-Kozioł A., Zuzanna Joanna K., Zakrzewska A., Lanzi M., Nakielski P., Pierini F., Gold Nanostar-Decorated Electrospun Nanofibers Enable On-Demand Drug Delivery, Macromolecular Rapid Communications, ISSN: 1022-1336, DOI: 10.1002/marc.202500033, pp.2500033-1-10, 2025

Abstract:
This study explores the development of a photo-responsive bicomponent electrospun platform and its drug delivery capabilities. This platform is composed of two polymers of poly(lactide-co-glycolide) (PLGA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). Then, the platform is decorated with plasmonic gold nanostars (Au NSs) that are capable of on-demand drug release. Using Rhodamine-B (RhB) as a model drug, the drug release behavior of the bi-polymer system is compared versus homopolymer fibers. The RhB is incorporated in the PHBV part of the platform, which provides a more sustained drug release, both in the absence and presence of near-infrared (NIR) irradiation. Under NIR exposure, thermal imaging reveals a notable increase in surface temperature, facilitating enhanced drug release. Furthermore, the platform demonstrates on-demand drug release upon multiple NIR irradiation cycles. This platform offers a promising approach for stimuli-responsive drug delivery, making it a strong candidate for on-demand therapy applications.

Orthey A., Dieguez P., Makuta O., Remigiusz A., High-dimensional monitoring and the emergence of realism via multiple observers, Physical Review A, ISSN: 2469-9926, DOI: 10.1103/PhysRevA.111.012220, Vol.111, No.012220, pp.1-10, 2025

Abstract:
Correlation is the basic mechanism of every measurement model, as one never accesses the measured system directly. Instead, correlations are created, codifying information about the measurable property into the environment. Here, we address the problem of the emergence of physical reality from the quantum world by introducing a model that interpolates between weak and strong nonselective measurements for qudits. By utilizing Heisenberg-Weyl operators, our model suggests that independently of the interaction intensity between the system and the environment, full information about the observable of interest can always be obtained by making the system interact with many environmental qudits, following a quantum Darwinism framework.

Kiełczyński P.M., Wieja K., Balcerzak A., New Torsional Surface Elastic Waves in Cylindrical Metamaterial Waveguides for Sensing Applications, SENSORS, ISSN: 1424-8220, DOI: 10.3390/ s25010143, Vol.25, pp.1-15, 2025

Abstract:
In this paper, we demonstrate that torsional surface elastic waves can propagate along the curved surface of a metamaterial elastic rod (cylinder) embedded in a conventional elastic medium. The crucial parameter of the metamaterial rod is its elastic compliance s441(ω), which varies as a function of frequency ω analogously to the dielectric function ε(ω) in Drude’s model of metals. As a consequence, the elastic compliance s441(ω) can take negative values s441(ω)< 0 as a function of frequency ω. Negative elastic compliance s441(ω) enables the emergence of new surface states, i.e., new types of surface elastic waves. In fact, the proposed torsional elastic surface waves can be considered as an elastic analog of Surface Plasmon Polariton (SPP) electromagnetic (optical) waves propagating along a metallic rod (cylinder) embedded in a dielectric medium. Consequently, we developed the corresponding analytical equations, for the dispersion relation and group velocity of the new torsional elastic surface wave. The newly discovered torsional elastic surface waves exhibit virtually all extraordinary properties of their electromagnetic SPP counterparts, such as strong subwavelength concentration of the wave energy in the vicinity of the cylindrical surface (r = a ) of the guiding rod, very low phase and group velocities, etc. Therefore, the new torsional elastic surface waves can be used in: (a) nearfield subwavelength acoustic imaging (super-resolution), (b) acoustic wave trapping (zero group and phase velocity), etc. Importantly, the newly discovered torsional elastic surface waves can form a basis for the development of a new generation of ultrasonic sensors (e.g., viscosity sensors), biosensors, and chemosensors with a very high mass sensitivity.

Keywords:
torsional elastic waves,elastic metamaterials ,negative elastic compliance ,dispersion curves ,phase velocity ,group velocity ,mass sensitivity ,viscosity sensors

Knap L., Graczykowski C., Holnicki-Szulc J. K., Vehicle Vibration Reduction Using Hydraulic Dampers with Piezoelectric Valves, SENSORS, ISSN: 1424-8220, DOI: 10.3390/s25041156, Vol.25, No.4, pp.1156-1-21, 2025

Abstract:
Ensuring adequate comfort and safety in vehicle motion is a subject of extensive research worldwide. Despite the implementation of new control algorithms, including those lever-aging AI, the application of effective semi-active vibration dampers remains crucial for achieving optimal suspension performance. This article presents experimental studies conducted on a vehicle equipped with semi-active suspension featuring custom-designed hydraulic dampers controlled by piezoelectric valves. These innovative dampers are characterized by extremely short response times, enabling real-time adaptation to varying driving conditions. A simple control algorithm designed to operate based on real-time signals from suspension sensors is introduced and evaluated. The experimental setup, in-cluding the measurement system used during testing, is described in detail. The presented results highlight the significant potential of this approach for improving driver comfort under specific driving conditions, even without detecting road roughness ahead of the ve-hicle.

Keywords:
semi-active suspension, piezoelectric valve, suspension sensors, ride comfort and safety

Bajkowski J. M., Bajer C. I., Dyniewicz B., Bajkowski J., Leonowicz M., Performance of a vibration damper using a new compressible magnetorheological fluid with microspheres, SMART MATERIALS AND STRUCTURES, ISSN: 0964-1726, DOI: 10.1088/1361-665X/ad9cd7, Vol.34, pp.1-12, 2025

Abstract:
A novel magnetorheological (MR) fluid was synthesised by incorporating compressible, nonmagnetic polyurethane microspheres and ferromagnetic iron particles into polyalphaolefin oil. This innovative composition reduces sedimentation, enhances compressibility beyond that of conventional MR fluids, and achieves comparable yield stress with a lower concentration of iron particles. The new MR fluid was evaluated in a prototype translational vibration damper under dynamic conditions across a range of excitation frequencies. The damper’s response with the compressible fluid differed significantly from that observed with non-compressible fluids. Upon activation, the MR fluid increased flow resistance and enhanced the damper’s elastic response, posing unique challenges for further optimisation. Experimental results demonstrate the potential of employing such compressible MR fluids in applications requiring controlled material characteristics.

Keywords:
smart material, magnetorheological (MR) fluid, compressible, microspheres, vibration, damper

Faraj R., Popławski B., Gabryel D., Mikułowski G., Wiszowaty R., On optimization of an adaptive pneumatic impact absorber – the innovative rescue cushion, BULLETIN OF THE POLISH ACADEMY OF SCIENCES: TECHNICAL SCIENCES, ISSN: 0239-7528, DOI: 10.24425/bpasts.2025.153436, pp.1-12, 2025

Abstract:
The paper states a complex study on the adaptive rescue cushion and concerns a problem of efficient impact mitigation, which is present during evacuation or assurance of people conducted by fire brigades. In order to minimize negative effects of person’s fall from height an airbag system is applied. Unfortunately, until now only passive solutions have been used. As a result, loads acting on a landing person were not minimized, because passive systems are designed for predefined, extreme conditions. Since the authors proposed to introduce adaptation mechanisms into the rescue cushion, a number of issues arose. They include construction and control of release vents, taking into account the inaccuracies of estimated impact parameters, and optimization of the venting area in case the evacuated person lands outside the airbag’s
center. All these problems were addressed within this paper and described in detail. Discussion on the system adaptation and its optimization was preceded by experimental validation of a numerical model. The energy absorbing capabilities of widely used passive rescue cushions were significantly enhanced as a result of the conducted research.

Keywords:
adaptive airbag, Adaptive Impact Absorption, inflatable structure, pneumatic absorber, rescue cushion

Loris R., Antun J., Będkowski J., Jurica J., The affordable DIY Mandeye LiDAR system for surveying caves, and how to convert 3D clouds into traditional cave ground plans and extended profiles, International Journal of Speleology, ISSN: 0392-6672, DOI: 10.5038/1827-806X.53.3.2535, Vol.53, No.3, pp.ijs2535-1-ijs2535-14, 2025

Abstract:
The paper examines the potential use of low-cost LiDAR for cave surveying. Mobile mapping using LiDAR complements traditional speleological surveying using a polygonal traverse. These methods assist each other, with one serving as an independent control measurement for the other, ultimately resulting in a more accurate 3D model. The testing results show that achieving high accuracy and detailed cave representation is possible using open hardware and open-source software. Both spacious and well-indented cave sections and narrow passages barely passable by humans were successfully mapped. The surveying process is significantly faster than traditional cave mapping, as drawing cave sketches by hand is unnecessary, being the most time-consuming task on site. This paper also presents a procedure for automated ground plan generation and profile generation from 3D point clouds, further expediting and simplifying the work for speleologists using scanning systems. Also, it is confirmed that the results are reproducible and do not depend on the subjective interpretation of the cartographer, as is the case with traditional speleological drawings.

Keywords:
cave mapping, mobile laser scanning, open hardware, open-source software, cave profiles

Ramírez-Cortés Sara A., Durán-Vargas A., Rauda-Ceja Jesús A., Mendoza-Espinosa P., Cofas Vargas L.F., Cruz-Rangel A., Pérez-Carreón Julio I., García-Hernandez E., Targeting human prostaglandin reductase 1 with Licochalcone A: Insights from molecular dynamics and covalent docking studies, Biophysical Chemistry, ISSN: 0301-4622, DOI: 10.1016/j.bpc.2025.107410, Vol.320-321, pp.107410-1-15, 2025

Abstract:
Prostaglandin reductase 1 (PTGR1) is an NADPH-dependent enzyme critical to eicosanoid metabolism. Its elevated expression in malignant tumors often correlates with poor prognosis due to its role in protecting cells against reactive oxygen species. This study explores the inhibitory potential of licochalcone A, a flavonoid derived from Xinjiang licorice root, on human PTGR1. Using molecular dynamics simulations, we mapped the enzyme's conformational landscape, revealing a low-energy, rigid-body-like movement of the catalytic domain relative to the nucleotide-binding domain that governs PTGR1's transition between open and closed states. Simulations of NADPH-depleted dimer and NADPH-bound monomer highlighted the critical role of intersubunit interactions and coenzyme binding in defining PTGR1's conformational landscape, offering a deeper understanding of its functional adaptability as a holo-homodimer. Covalent docking, informed by prior chemoproteomic cross-linking data, revealed a highly favorable binding pose for licochalcone A at the NADPH-binding site. This pose aligned with a transient noncovalent binding pose inferred from solvent site-guided molecular docking, emphasizing the stereochemical complementarity of the coenzyme-binding site to licochalcone A. Sequence analysis across PTGR1 orthologs in vertebrates and exploration of 3D structures of human NADPH-binding proteins further underscore the potential of the coenzyme-binding site as a scaffold for developing PTGR1-specific inhibitors, positioning licochalcone A as a promising lead compound.

Keywords:
Leukotriene B4 dehydrogenase,NADPH-dependent enzyme,Molecular dynamics simulation,Covalent inhibition,Specific target for cancer therapy

Krysiak Z., Rybak D., Kurniawan T., Zakrzewska A., Pierini F., Light-Driven Structural Detachment and Controlled Release in Smart Antibacterial Multilayer Platforms, Macromolecular Materials and Engineering, ISSN: 1438-7492, DOI: 10.1002/mame.202400462, pp.2400462-1-9, 2025

Abstract:
Smart materials, especially light-responsive, have become a key research area due to their tunable properties. It is related to the ability to undergo physical or chemical changes in response to external stimuli. Among them, photothermal responsive materials have attracted great interest. This study focuses on the development of a multilayer system (MS) consisting of benzophenone-modified polydimethylsiloxane (PDMS) ring and a thermo-responsive core made of poly(N-isopropylacrylamide-co-N-isopropylomethacrylamide) (P(NIPAAm-co-NIPMAAm)), gelatin, and gelatin methacrylate (GelMA). The system utilizes the thermal sensitivity of P(NIPAAm-co-NIPMAAm) and the photothermal effect of gold nanorods (AuNRs) to achieve an on-demand controlled release mechanism within 6 min of near-infrared (NIR) light irradiation. The mechanical properties investigated in the compression test show significant improvement in MS, reaching 60 times greater value than the material without a PDMS ring. In addition, NIR irradiation for 15 min activated the antimicrobial properties, eliminating 99.9% of E. Coli and 100% of S. Aureus, thus presenting pathogen eradication. This platform provides a versatile methodology for developing next-generation smart materials, advanced delivery mechanisms, and multifunctional nanostructured composites. This work highlights the potential of photosensitive materials to revolutionize the field of soft robotics, optics and actuators, and on-demand systems by providing precise control over release dynamics and improved material properties.

Nazir S., Singh P., Rawat N., Jain A., Michalska M., Yahya M., Yusuf S., Diantoro M., Polyether (polyethylene oxide) derived carbon electrode material and polymer electrolyte for supercapacitor and dye-sensitized solar cell, Ionics, ISSN: 0947-7047, DOI: 10.1007/s11581-024-06052-9, pp.1-11, 2025

Abstract:
This study investigates the development and performance analysis of a supercapacitor using activated carbon synthesized from polyethylene oxide (PEO) as the electrode material, and a poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP)-based polymer electrolyte, prepared using a solution-cast technique for dye-sensitized solar cell (DSSC) application. This paper deals with polyether-based electrochemical devices, where electrode material is developed by polyethylene oxide (PEO), while an electrolyte is prepared using PVdF-HFP. Detailed electrical and photoelectrochemical studies were carried out using various characterization tools, and the results are discussed in detail. Sandwich structure supercapacitors and DSSCs are developed using maximum conducting polymer electrolyte that has an ionic conductivity of (8.3 × 10−5) Scm−1, exhibiting a high specific capacitance of 395 Fg−1 and DSSC efficiency ranging from 1.6 to 3.5% under 1 sun condition. The findings underscore the capability of PEO-derived carbon and polymer electrolytes in improving the efficiency of energy storage and conversion systems.

Keywords:
Polyether, Activated carbon, Supercapacitor, Dye-sensitized solar cell

Ngoc Tien N., Tien Dat N., Ba Manh N., Thi Thanh Ngan N., Osial M., Pisarek M., Chernyayeva O., Vu Thi T., A simple one-pot approach to prepare composites based on bimetallic metal–organic frameworks M, Ni-BTC (M = Cu, Fe) and carbon nanotubes for electrochemical detection of bisphenol A, Journal of Nanoparticle Research, ISSN: 1388-0764, DOI: 10.1007/s11051-025-06287-1, Vol.27, No.87, pp.1-16, 2025

Keywords:
electrochemistry, sensor, bisphenol A, MOF, CNT

Grigoryan N., Chudziński P., Tomonaga–Luttinger Liquid Parameters in Multiwalled Nanotubes, PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS, ISSN: 0370-1972, DOI: 10.1002/pssb.202400524, Vol.2400524, pp.1-10, 2025

Abstract:
Tomonaga–Luttinger liquid (TLL) theory is a canonical formalism used to describe 1D metals, where the low-energy physics is determined by collective Bosonic excitations. Herein, a theoretical model to compute the parameters of Tomonaga–Luttinger liquid (TLL) in multiwalled nanotubes (MWNTs) is presented. MWNTs introduce additional complexity to the usual Fermionic chains due to interactions and hybridization between their multiple coaxial shells. A model in which conducting paths along the length of the MWNTs are randomly distributed among the shells is considered. Since the valley degree of freedom remains a good quantum number, the TLL description in addition to spin and charge contains also valley degree of freedom and hence four-mode description applies. The values of all four TLL parameters are obtained for this model. A surprising outcome is that the compressibility of the holon mode becomes a universal quantity, while the parameters of neutral modes will depend on the details of intershell coupling. Finally, experiments where predictions can be tested are proposed.

Konwar S., Kumar S., Mohamad A., Jain A., Michalska M., Punetha V., Yahya M., Strzałkowski K., Dharmendra Pratap S., Diantoro M., Chowdhury F., Singh P., Ionic liquid (1-Ethyl-3-methylimidazolium tricyanomethanide) incorporated corn starch polymer electrolyte for solar cell and supercapacitor application, Chemical Physics Impact, ISSN: 2667-0224, DOI: 10.1016/j.chphi.2024.100780, Vol.10, pp.1-7, 2025

Abstract:
Taking into account energy demand a new highly conducting ionic liquid (IL) c (EmImTCM) mixed corn starch (CS) biopolymer electrolyte is synthesized for dual electrochemical application electric double layer capacitor (EDLC) and the dye-sensitized solar cell (DSSC) application. Electrical, structural, thermal, and optical studies are carried out in detail and presented in this communication. Maximum conducting IL-incorporated biopolymer electrolyte film has been sandwiched between electrodes to develop EDLC and DSSC. The sandwich-structured EDLC delivers a high specific capacitance of 250 F/gram while DSSC shows 1.44 % efficiency at one sun condition.

Keywords:
Corn starch, Biopolymer, XRD, TGA, EDLC, DSSC

Zargarian S., Rinoldi C., Ziai Y., Zakrzewska A., Fiorelli R., Gazińska M., Marinelli M., Majkowska M., Hottowy P., Mindur B., Czajkowski R., Kublik E., Nakielski P., Lanzi M., Kaczmarek L., Pierini F., Chronic Probing of Deep Brain Neuronal Activity Using Nanofibrous Smart Conducting Hydrogel-Based Brain–Machine Interface Probes, Small Science, ISSN: 2688-4046, DOI: 10.1002/smsc.202400463, pp.2400463-1-19, 2025

Abstract:
The mechanical mismatch between microelectrode of brain–machine interfaces (BMIs) and soft brain tissue during electrophysiological investigations leads to inflammation, glial scarring, and compromising performance. Herein, a nanostructured, stimuli-responsive, conductive, and semi-interpenetrating polymer network hydrogel-based coated BMIs probe is introduced. The system interface is composed of a cross-linkable poly(N-isopropylacrylamide)-based copolymer and regioregular poly[3-(6-methoxyhexyl)thiophene] fabricated via electrospinning and integrated into a neural probe. The coating's nanofibrous architecture offers a rapid swelling response and faster shape recovery compared to bulk hydrogels. Moreover, the smart coating becomes more conductive at physiological temperatures, which improves signal transmission efficiency and enhances its stability during chronic use. Indeed, detecting acute neuronal deep brain signals in a mouse model demonstrates that the developed probe can record high-quality signals and action potentials, favorably modulating impedance and capacitance. Evaluation of in vivo neuronal activity and biocompatibility in chronic configuration shows the successful recording of deep brain signals and a lack of substantial inflammatory response in the long-term. The development of conducting fibrous hydrogel bio-interface demonstrates its potential to overcome the limitations of current neural probes, highlighting its promising properties as a candidate for long-term, high-quality detection of neuronal activities for deep brain applications such as BMIs.

Szostakowska-Rodzoś M., Chmielarczyk M., Weronika Z., Fabisiewicz A., Kurzyk A., Myśliwy I., Kozaryna Z., Postek E. W., Grzybowska E., Plasticity of Expression of Stem Cell and EMT Markers in Breast Cancer Cells in 2D and 3D Culture Depend on the Spatial Parameters of Cell Growth; Mathematical Modeling of Mechanical Stress in Cell Culture in Relation to ECM Stiffness, Bioengineering, ISSN: 2306-5354, DOI: 10.3390/bioengineering12020147, Vol.147, No.12, pp.1-22, 2025

Abstract:
The majority of the current cancer research is based on two-dimensional cell cultures and animal models. These methods have limitations, including different expressions of key factors involved in carcinogenesis and metastasis, depending on culture conditions. Addressing these differences is crucial in obtaining physiologically relevant models. In this manuscript we analyzed the plasticity of the expression of stem cell and epithelial/mesenchymal markers in breast cancer cells, depending on culture conditions. Significant differences in marker expression were observed in different growth models not
only between 2D and 3D conditions but also between two different 3D models. Differences observed in the levels of adherent junction protein E-cadherin in two different 3D models suggest that spatial parameters of cell growth and physical stress in the culture may affect
the expression of junction proteins. To provide an explanation of this phenomenon on the grounds of mechanobiology, these parameters were analyzed using a mathematical model of the 3D bioprinted cell culture. The finite element mechanical model generated in this study includes an extracellular matrix and a group of regularly placed cells. The single-cell model comprises an idealized cytoskeleton, cortex, cytoplasm, and nucleus. The analysis of the model revealed that the stress generated by external pressure is transferred between the cells, generating specific stress fields, depending on growth conditions. We have analyzed and compared stress fields in two different growth conditions, each corresponding to a different elasticity of extracellular matrix. We have demonstrated that soft matrix conditions produce more stress than a stiff matrix in the single cell as well as in cellular spheroids. The observed differences can explain the plasticity of E-cadherin expression in response to mechanical stress. These results should contribute to a better understanding of the differences between various growth models.

Keywords:
breast cancer, E-cadherin, mechanical stress, mathematical modeling, 3D bioprinting, complex systems, cell modeling, finite element method