Latest Publications

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

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

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

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

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.

Abstract:
NF2-related Schwannomatosis (NF2 SWN) is a rare disease characterised by the growth of multiple nervous system neoplasms, including bilateral vestibular schwannoma (VS). VS tumours are characterised by extensive leucocyte infiltration. However, the immunological landscape in VS and the spatial determinants within the tumour microenvironment that shape the trajectory of disease are presently unknown. In this study, to elucidate the complex immunological networks across VS, we performed imaging mass cytometry (IMC) on clinically annotated VS samples from NF2 SWN patients. We reveal the heterogeneity in neoplastic cell, myeloid cell and T cell populations that co-exist within VS, and that distinct myeloid cell and Schwann cell populations reside within varied spatial contextures across characteristic Antoni A and B histomorphic niches. Interestingly, T-cell populations co-localise with tumour-associated macrophages (TAMs) in Antoni A regions, seemingly limiting their ability to interact with tumorigenic Schwann cells. This spatial landscape is altered in Antoni B regions, where T-cell populations appear to interact with PD-L1+ Schwann cells. We also demonstrate that prior bevacizumab treatment (VEGF-A antagonist) preferentially reduces alternatively activated-like TAMs, whilst enhancing CD44 expression, in bevacizumab-treated tumours. Together, we describe niche-dependent modes of T-cell regulation in NF2 SWN VS, indicating the potential for microenvironment-altering therapies for VS.

Abstract:
In this study, the AlCoCrFeNiTi0.2 high-entropy alloy (HEA) was plasma nitrided to investigate the microstructure and mechanical properties of high-entropy nitrides formed in the surface layer of the bulk sample. XRD measurements revealed a BCC → FCC crystal structure transformation, with the σ phase disappearing and hexagonal aluminum nitride emerging. Further experimental studies on the nitrided samples, including SEM, EDS, and EBSD, uncovered element segregation into multiple FCC phases with similar lattice constants, such as the NaCl-type (AlCrCoFeNiTi0.2)N high-entropy nitride. These observations align with theoretical analysis based on KKR-CPA calculations. Additionally, plasma nitriding induced high surface porosity; however, micropillar compression testing combined with nanoindentation revealed localized areas with significant hardness. A substantial reduction in the coefficient of friction was also observed. These findings not only provide deeper insights into the nitriding process of complex alloys, like dual-phase HEAs, but also hold promise for further exploration in the manufacturing of super-hard surfaces with high-entropy nitrides, enhancing mechanical properties for applications in harsh environments.

Abstract:
Performance of a structural health monitoring (SHM) system depends on the set of sensors distributed across the monitored structure. Optimal deployment of sensors on large-scale structures, such as tied-arch bridges, is a significant challenge. Condition assessment of a bridge is typically based on its displacement response under operational or diagnostic loads. However, direct displacement measurements require reference-based methods, which is problematic for bridges. Consequently, other sensor types that do not require reference points, such as accelerometers or inclinometers, are commonly used in practice. These sensors can indirectly provide displacement information but require sophisticated numerical integration and filtering techniques. Deploying a sensor network becomes even more challenging when it is heterogeneous and simultaneously utilizes sensors of various types. This paper proposes a sensor placement method for distributing such heterogeneous sensor networks. Two computationally efficient procedures are introduced, based on Kalman filtering and response estimation uncertainty. Their effectiveness is demonstrated using a realistic example of a tied-arch bridge located in Poland. One algorithm operates in a discrete greedy manner, while the other fuzzifies the sensor set to convert the originally discrete problem into a continuous one. Their numerical efficiency is related to the computationally inexpensive use of the cross-covariance matrix between the sensor responses and the target responses of interest. Compared to an existing multi-type sensor placement method, the proposed algorithms yield results of comparable quality with several times smaller computational cost.

Keywords:
Sensor networks, Optimal sensor placement, Kalman filter, Convex relaxation

Abstract:
In the Big Data era, a change of paradigm in the use of molecular dynamics is required.
Trajectories should be stored under FAIR (findable, accessible, interoperable and
reusable) requirements to favor its reuse by the community under an open science paradigm.

Keywords:
FAIR principles,MD,Data,Biomolecular Simulation

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)

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

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

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

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

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.

Abstract:
The flexural vibration of miniaturized homogeneous isotropic beams with multiple cracks is investigated using the mixture unified gradient elasticity theory. The model captures both possible stiffening and softening size-dependence at small scales. The problem is addressed using the Bernoulli-Euler beam theory, with the domain partitioned into distinct sections at cracked cross-sections. Cracks are assumed to be non-propagating, sufficiently spaced to avoid interaction, and open during vibration. The elastic spring model is employed to capture the effect of cracks on the dynamic characteristics. The time-dependent variational functional is rigorously established to derive variationally consistent and extra non-standard boundary and continuity conditions. Natural frequencies are obtained by solving the eigenvalue problem resulting from the imposition of boundary and continuity conditions. The predictions demonstrate excellent agreement with experimental, molecular dynamics, and analytical data from the literature for both large- and small-scale beams. The model is applied to examine the effects of gradient characteristic parameters, crack length and location, and boundary conditions on the frequencies. The practical application of the model to the inverse problem, where the location and length of a crack are unknown a priori, is numerically analyzed. The results indicate that the size effect significantly influences the inverse problem solution.

Abstract:
The study investigates the role of the topology of the additively manufactured AlSi10Mg cellular structures in the example of 3D and 2D designs: honeycomb, auxetic, lattice and foam. The samples were subjected to quasistatic and blast-induced dynamic compression. As a result, a relation between the structural geometry and the deformation mode of the compressed structures has been developed, demonstrating its influence on the energy absorption characteristics. The deformation and fracture mechanisms were examined in detail using the finite element simulations in the LS-DYNA code based on the material characterisation over a broad range of strain rates and temperatures. The outcomes show an agreement between the experimental data and the computations. The obtained results prove that by selecting the appropriate topological features, the deformation of compressed structures can be enhanced to improve their energy-absorption capacity.

Keywords:
Additive manufacturing,AlSi10Mg,Direct metal laser sintering (DMLS),Cellular structures,Dynamic compression,Blast-energy absorption,Explosively-driven shock tube

Keywords:
Spark plasma sintering, Discrete element method, Thermo-electric coupling, Joule heating

Abstract:
The paradigmatic state of a 1D collective metal, the Tomonaga-Luttinger liquid (TLL), offers us an exact
analytic solution for a strongly interacting quantum system not only for infinite systems at zero temperature
but also at finite temperature and with a boundary. These results are potentially of significant relevance for
technology, as they could lay the foundation for a many-body description of various nanostructures. For this
to happen, we need expressions for local (i.e., spatially resolved) correlations as a function of frequency. In
this paper, we find such expressions and study their outcome. Based on our analytic expressions, we are able to
identify two distinct cases of TLL, which we call the Coulomb metal and Hund metal, respectively. We argue that
these two cases span all the situations possible in nanotubes made out of p-block elements. From an applications viewpoint, it is crucial to capture the fact that the end of the 1D system can be coupled to the external environment and emit electrons into it. We discuss such coupling on two levels for both Coulomb and Hund metals: (i) in the zeroth-order approximation, the coupling modifies the 1D system’s boundary conditions; (ii) for stronger coupling, when the environment can self-consistently modify the 1D system, we introduce spatially dependent TLL parameters. In case (ii), we are able to capture the presence of plasmon-polariton particles, thus building a link between TLL and the field of nano-optics.

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

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

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

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

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

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

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

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

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

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

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

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.

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.

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

Abstract:
The global challenges of access to clean water and energy continue to grow, prompting research into sustainable solutions. A promising approach involves the conversion of agricultural waste into high-porosity functional materials for both water purification and energy storage. This study explores the conversion of stale bread into spongy carbon materials, which were evaluated as adsorbents for the removal of cationic dyes and electrodes for supercapacitors. The physical and chemical properties of the material were characterized using standard techniques. In particular, activated carbon produced at 900 °C showed a balanced mixture of micropores and mesopores, with a high specific surface area of ∼1583 m² g-1, making it a low-cost effective adsorbent for the removal of crystal violet dye, showing an adsorption capacity of 753.9 mg g-1, optimal at 10 mg of adsorbent dose with only 10 min of contact time. It performed well in a wide pH range (2–12) and in saline solutions. Furthermore, the material demonstrated a single electrode specific capacitance of ∼155 F g-1, an energy density of 21.6 Wh kg-1, and a power density of 355.9 kW kg-1 in supercapacitor applications. It exhibited high reversibility of charge-storage, retaining ∼85 % of its capacitance after 15,000 cycles. These results highlight the potential of pyrolyzed agricultural waste as a versatile and sustainable material for environmental and energy applications.

Keywords:
Activated carbon, Crystal violet, Dye adsorption, Energy storage application, Supercapacitor

Keywords:
Deep eutectic solvent, Gel-like polymer electrolyte, High-voltage supercapacitor, Quasi-solid state electrolyte, Symmetric supercapacitor

Abstract:
In recent years, non-degradable petroleum-based polymer packaging has generated serious disposal, pollution, and ecological issues. The application of biodegradable food packaging for common purposes could overcome these problems. Bio-based hydrogel films are interesting materials as potential alternatives to non-biodegradable commercial food packaging due to biodegradability, biocompatibility, ease of processability, low cost of production, and the absorption ability of food exudates. The rising need to provide additional functionality for food packaging has led scientists to design approaches extending the shelf life of food products by incorporating antimicrobial and antioxidant agents and sensing the accurate moment of food spoilage. In this review, we thoroughly discuss recent hydrogel-based film applications such as active, intelligent packaging, as well as a combination of these approaches. We highlight their potential as food packaging but also indicate the drawbacks, especially poor barrier and mechanical properties, that need to be improved in the future. We emphasize discussions on the mechanical properties of currently studied hydrogels and compare them with current commercial food packaging. Finally, the future directions of these types of approaches are described.

Keywords:
hydrogels,bio-based polymers,active packaging,intelligent packaging,food packaging

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

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.

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

Abstract:
Background: Popular science projects provide an opportunity for
students to explore scientific disciplines in a hands-on manner,
potentially influencing their future career choices, particularly in
science, technology, engineering, and mathematics (STEM) fields.
Purpose: The study aims to explore the potential impact of participation in science popularization workshops on high school students’ perception of STEM fields and their interest in pursuing careers in science. It examines students’ attitudes through survey data, including their self-reported interest in STEM disciplines, career aspirations, and reflections on the role of hands-on experience in shaping their educational choices.
Sample: The study involved high school students who participated
in a series of experimental workshops focused on the synthesis of
superparamagnetic iron oxide nanoparticles.
Design and methods: We analyze the relationship between popular
science projects carried out by high school students on the choice of
field of study and further professional path, i.e. their attitude towards
choosing a career path, and participation in workshops popularizing
science into account exact STEM. To achieve this goal, we designed
a series of experiments tailored to high school students.
Results: Students had the opportunity to study the 3D virtual representations of molecular geometry. Seventy-five percent of participants connected their professional path with the field of chemistry, and 35% declared interest in following an academic career.
Conclusion: These findings indicate that science popularization
workshops can significantly influence students’ perceptions of
STEM education and career paths. Engaging in laboratory activities,
collaborative problem-solving, and direct interactions with scientists
fostered a heightened interest in chemistry and related fields.
Based on the Social Cognitive Career Theory, self-efficacy and outcome expectations play a pivotal role in career choices. Our
results support this perspective, as students with positive workshop
experiences were more inclined to consider STEM studies.
Moreover, the hands-on approach bridged the gap between theoretical
learning and real-world scientific applications.

Keywords:
Science popularization,projects popularizing science,chemical education,chemical education,laboratory instructions

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

Abstract:
Prediction of the acoustic performance of 3D printed materials is investigated at normal and grazing incidence. A direct numerical (microscopic) simulation that solves the full set of Navier-Stokes equations is used as a reference. It is compared with a macroscopic approach in which the material is represented by an equivalent fluid. The materials have a periodic microstructure, consisting either of a single network of spherical or cubic cavities connected by cylindrical channels or of a double-nested network. The samples are printed using the stereolithography technique and are tested using an impedance tube and a duct test bench. For single network geometries, the results of sound absorption at normal and grazing incidence predicted using the equivalent fluid approach are in good agreement with those obtained by the microscopic approach. Comparisons with impedance tube measurements confirm that both approaches can accurately predict the absorption coefficient of the samples. For the in-duct liner configuration, the transmission loss measurements and predictions show similar evolution with frequency change, despite the discrepancy in amplitude. For the double network geometry, the equivalent fluid approach cannot exactly reproduce the results obtained with the direct numerical simulation. Finally, while the predictions with the microscopic approach provide a good match with the impedance tube measurements, only a poor agreement is obtained using the duct testing bench.

Keywords:
Acoustic absorber,3D printing,Duct,Multiscale approach

Abstract:
Plant pathogens pose a severe threat to global food security by compromising the availability, quality, and safety of crops for human and animal consumption. Given the urgent need for alternatives to chemical pesticides, natural inhibitors of phytopathogenic proteases represent promising biopesticides. Tarocystatin has been characterized in Colocasia esculenta as a defense protein against phytopathogenic nematodes and fungi. Despite its biotechnological potential, few studies describe its mechanical, structural, and energetic properties. In this study, we characterized the inhibitory mechanism of tarocystatin against papain using a computational biophysics approach. Through extensive molecular dynamics (MD) and steered molecular dynamics (SMD) simulations, we explored the dynamic, energetic, structural, and mechanical basis of tarocystatin and its specific binding to papain. Our results suggest that the stability of the complex is characterized by a lack of conformational rearrangements, showing invariability in its secondary structure across all MD replicas. Additionally, electrostatic analysis revealed a high complementarity of the tarocystatin-papain complex, which was later corroborated by the hydrogen-bond network established at the complex interface, explaining its strong inhibitory capacity. Moreover, we determined that the substrate-competitive inhibitory mechanism is due to the binding ability of conserved motifs in tarocystatin, which efficiently interact with the catalytic active site of papain. This was also confirmed through SMD, where we observed that the N-terminal region acts as a spring to prevent the dissociation of the complex under external pulling forces. Overall, our study is the first to provide a comprehensive exploration of the biophysical properties of the tarocystatin-papain complex, offering insights into the tarocystatin's inhibition mechanism. These results lay the foundation for future development of tarocystatin-based antifungal alternatives, as well as for exploring its inhibitory activity in other pathogens or enhancing its efficacy through molecular engineering.

Keywords:
Tarocystatin, Papain, Inhibition mechanism, Molecular dynamics, Computational biophysics

Abstract:
In perpetual voting, multiple decisions are made at different moments in time. Taking the history of previous decisions into account allows us to satisfy properties such as proportionality over periods of time. In this paper, we consider the following question: is there a perpetual approval voting method that guarantees that no voter is dissatisfied too many times? We identify a sufficient condition on voter behavior ---which we call 'bounded conflicts' condition---under which a sublinear growth of dissatisfaction is possible. We provide a tight upper bound on the growth of dissatisfaction under bounded conflicts, using techniques from Kolmogorov complexity. We also observe that the approval voting with binary choices mimics the machine learning setting of prediction with expert advice. This allows us to present a voting method with sublinear guarantees on dissatisfaction under bounded conflicts, based on the standard techniques from prediction with expert advice.

Abstract:
Delle Rose et al. (COLT’23) introduced an effective version of the Vapnik-Chervonenkis dimension, and showed that it characterizes improper PAC learning with total computable learners. In this paper, we introduce and study a similar effectivization of the notion of Littlestone dimension. Finite effective Littlestone dimension is a necessary condition for computable online learning but is not a sufficient one—which we already establish for classes of the effective Littlestone dimension 2. However, the effective Littlestone dimension equals the optimal mistake bound for computable learners in two special cases: a) for classes of Littlestone dimension 1 and b) when the learner receives as additional information an upper bound on the numbers to be guessed. Interestingly, a finite effective Littlestone dimension also guarantees that the class consists only of computable functions.

Keywords:
online learning, Littlestone dimension, computability

Abstract:
This paper investigates the gas transport behaviors of a special type of concrete—shielding concrete—designed for use in nuclear structures, where mitigating radiation and ensuring long-term durability in harsh environments are critical. Cracking is identified as a key factor influencing gas transport in nuclear environments, where it plays a critical role in determining material performance. In the current phase of the research, cracks and gaps, caused by significant variations in the interfacial transition zone (ITZ) and influenced by thermal treatment of concrete, depending on the type of aggregate and cement, were analyzed. Three types of concrete mixtures incorporating magnetite, serpentinite, and a combination of both aggregates are studied, alongside two types of cement: CEM I and CEM III. The transport properties of these concrete mixes, crucial for assessing their performance in nuclear shielding applications, were evaluated using three complementary methods: the Cembureau method for gas permeability, the Torrent method for measuring surface permeability, and the Air Permeability Index (API) using the Autoclam method. Additionally, microstructural analysis was conducted using scanning electron microscopy (SEM) to gain deeper insights into the material's behavior. The impact of microcracks on permeability was examined, as such cracks often behave differently under gas transport conditions. In the next phase of the research, supplementary cracking will be intentionally induced, both mechanically and thermally, to simulate the conditions expected in typical nuclear operations.

Keywords:
Shielding Concrete, Gas Permeability, Microstructure, Interfacial Transition Zone, Cracking