Irradiation at ultra-high dose rates is gaining increased attention due to its ability to limit damage to surrounding healthy tissues, thereby preventing radiation-induced side effects. Although there are some exceptions, this protective effect (the FLASH effect) has been demonstrated in many preclinical models, primarily after low-LET irradiation and high-dose irradiation. Here, we report that both ultra-high dose rate (UHDR) and conventional dose rate (CONV) irradiations produce similar growth delays in 3D tumor spheroids (composed of HCT116 and T98G, colorectal carcinoma or glioblastoma cell lines), indicating comparable efficacy in tumor control. In normal cells (HIEC-6, a non-malignant epithelial cell line from the small intestine), UHDR and CONV irradiation induced comparable senescence, while a lower induction of apoptosis was observed after UHDR irradiation at clinically relevant doses and early time points postirradiation. Collectively, these findings highlight the potential of UHDR irradiation to modulate normal tissue responses while achieving comparable tumor control.

OBJECTIVES:Ultra-high dose rate (UHDR) irradiation spares normal tissues while achieving similar tumour control compared to conventional dose rate (CONV) irradiation in a preclinical setting. However, the underlying biological mechanisms remain unclear. In this study, we examined the relationship between DNA damage and UHDR proton irradiation in both normal and cancerous pancreatic cells. METHODS:Normal human pancreatic cells (H6c7) and human pancreatic adenocarcinoma cells (PANC-1) were exposed to 3 and 15 Gy of 4 MeV protons (LET = 10 keV/µm) at 0.025 Gy/s (CONV) or 375 Gy/s (UHDR) under normoxic (21% O2) or hypoxic (1% O2) conditions. DNA damage was assessed by yH2AX immunofluorescence and by the alkaline comet assay. RESULTS:Following 3 Gy irradiation, no significant differences in DNA damage were found between UHDR- and CONV-irradiated cells. In contrast, 15 Gy of UHDR irradiation significantly reduced DNA damage in H6c7 cells compared to CONV irradiation under hypoxia but not normoxia. No statistically significant FLASH sparing was found in PANC-1 cells irradiated with 15 Gy under either normoxic or hypoxic conditions. CONCLUSIONS:UHDR proton irradiation shows potential in reducing radiation-induced DNA damage in normal but not cancer cells compared to CONV proton irradiation at relatively high doses and low oxygen levels. ADVANCES IN KNOWLEDGE:This is the first study that compared the responses of normal and cancerous cells-from the same background-to UHDR and CONV proton irradiation. In addition, our data confirm the importance of dose and oxygen concentration for observing the FLASH effect in normal cells.

Surfaces are well-established direct and indirect vectors for the propagation of pathogens such as bacteria and viruses. One strategy to mitigate this issue is to modify surface properties by depositing antimicrobial thin films using magnetron sputtering. Hydrogenated amorphous diamond-like carbon coatings doped with silver and chromium (a-C:H:Ag) are promising candidates due to their ability to reduce bacterial adhesion while simultaneously providing robust protective and decorative functions. However, a-C:H coatings often suffer from poor adhesion and the incorporation of Ag reduces their mechanical performances. Incorporating chromium offers an effective approach to overcome this limitation This study investigates the mechanical properties of a-C:H:Cr:Ag coatings, their bactericidal activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive), as well as their antiviral performance against a coronavirus. The results demonstrate that the addition of Cr significantly enhances mechanical properties without compromising their antimicrobial performance.

Magnetron sputtering is a versatile and scalable technique that enables the precise tuning of key properties, including crystalline phase, stoichiometry, and phase ratios. Despite its widespread use in producing dense non‐porous coatings on flat substrates, its potential for developing porous electroactive materials remains underexplored. Here the use of rough substrates, such as carbon nanotubes and nanosheets, revealing a dramatic change in the growth mechanism of this model systems, nickel nitride, and chromium nitride is investigated. The nanometric roughness of these carbon nanomaterials leads to distinct effects, including strong shadowing of deposited species and non‐competitive growth. This results in enhanced porous thin films with open microstructures and high available surface areas. It is then apply the experimental findings, confirmed by Monte Carlo simulations, to other thin films to demonstrate this approach extends to multiple nanorough substrate/thin film systems, thereby paving the way for designing new materials with enhanced energy conversion and storage performance.

The efficiency of surface-mediated dissociation depends on the energy barriers that radicals must overcome to stabilize on catalyst surfaces. In this study, we synthesized gold nanoparticles (AuNPs) and bimetallic gold-silver nanoparticles using both green and conventional chemical methods. We tested their catalytic activity for the breakdown of Methylene Blue (MB) and Methyl Orange (MO) using sodium borohydride as the reducing agent. Although dye degradation is well understood in laboratory conditions, its behavior in real water is less clear. To explore this, we ran experiments in tap, river, and marine water. The results showed that higher salinity led to much faster reaction rates. In seawater, MB and MO broke down 2.9 and 1.8 times faster than in deionized water. Greater salinity also boosted the catalytic activity of bimetallic G-AuAgNPs, with acceleration factors of 27 for MB and 7 for MO. This improvement is likely due to interactions between biogenic groups and the salty environment, which alter the nanoparticles' surface charge and stability. Density Functional Theory (DFT) simulations of Na–Au(111) models showed that biogenic surface chemistry helps chloride (Cl-) desorb, and sodium on the surface lowers the energy needed for dye molecules to break apart.

The deposition of functional coatings on open-cell foam substrates using magnetron sputtering is gaining popularity, particularly for applications like oxygen evolution reaction/hydrogen evolution reaction catalysis, batteries, and supercapacitors. While most research focuses on performance, little attention has been paid to the coating growth mechanisms or properties within the foam, which could significantly impact device performance. This work investigates the properties and growth mechanisms of TiO 2 coatings inside porous foams, using experimental and modeling techniques. The structure, composition and thickness of the coating on the outermost surface of the foam are studied using focused ion beam (FIB), scanning transmission electron microscopy (STEM), energy-dispersive x-ray spectroscopy (EDS), selected area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM). The experimental results reveal the formation of a dense, (quasi-)stoichiometric and crystalline coating. Numerical simulations and experiments highlight the transport of plasma particles in the foam. Interestingly, direct simulation Monte Carlo (DSMC)/particle-in-cell Monte Carlo (PICMC) models, coupled with mass-energy analyzer (MEA) experiments, demonstrate that the particle flux is reduced, but the particle energy distribution is not affected while traveling inside the foam. Using kinetic Monte Carlo thin film growth models provided by Virtual Coater TM , the physical properties of the coating inside the foam have been modeled, and the drop in coating thickness as well as the impact of bias voltage on densification, resistivity, and optical absorption are confirmed. synchrotron x-ray diffraction (SXRD) analyses of the foam demonstrate that the same crystalline phase is obtained along the foam thickness, but it can be tailored with bias voltages. The decrease in the recorded SXRD signal with increasing depth inside the foam also suggests a drop in coating thickness. The new insights on the properties of coatings inside open-cell foams presented in this study can be used to improve future foam-based devices.

A high-Mn austenitic steel Fe-14Cr-12Ni-10Mn-3Cu-2.5Al-1Nb was tested at 500 degrees C in static Pb-Bi eutectic for 10000 h. In the course of the test, oxygen concentration in liquid metal was cycled from ' 10-6 to ' 10-9 mass%, which provides oxidation and dissolution regimes, respectively. After 10000 h exposure steel showed formation of ferrite corrosion zone depleted in Mn, Ni, Cu, Cr, Fe and penetrated by Pb and Bi. Average depth of corrosion is 15 +/- 5 mu m, while maximum corrosion depth locally reaches ' 35 mu m. Dissolved Mn and Cr re-precipitated in the vicinity of steel surface in a form of stratified Mn-O/Cr-Mn-O oxide scale. Obtained results were compared to those of similar Al-alloyed austenitic steels with lower Mn content, which exhibited protective oxidation under same test conditions. The phenomenological mechanism of oxygen-driven de-alloying of steel in Pb-Bi[O] is discussed. (c) 2024 The Author(s). Published by Elsevier B.V. on behalf of Institute of Metal Research, Chinese Academy of Sciences. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Objective. To elucidate the initial chemical mechanisms that may underlie the FLASH effect by developing and validating a unified simulation framework for the radiolysis of pure water. The goal is to create a single model capable of reconciling conflicting experimental and simulation data regarding H₂O₂ production and explaining key radiobiological observations across conventional (CDRs) and ultra-high dose rates (UHDRs) under varied oxygenation levels. Approach. An ordinary differential equation-based model was developed to simulate the homogeneous chemistry phase of water radiolysis. The framework incorporates a detailed chemical reaction network and a novel description of acid–base equilibrium, allowing pH to evolve dynamically. A key innovation is the integration of an empirically derived, dose-rate dependent G -value coefficient ( G F ( D R )) that anchors the simulation to experimental data. The temporal evolution of key species (H₂O₂, O₂, H₃O + , OH − ) is tracked to investigate the impact of dose rate and oxygen concentration. Main results. The model reproduces two key experimental findings relevant to the FLASH effect—previously challenging for simulations: decreased net H₂O₂ production at UHDR under physioxic conditions. This reduction (vs CDR) aligns with normal tissue sparing, while hypoxic (tumour-like) conditions show comparable H₂O₂ production at UHDR and CDR, consistent with iso-tumour control. These results confirm that H₂O₂ radiochemistry is profoundly influenced by both dose rate and oxygen levels. Significance. This work resolves a key discrepancy between previously published simulations and experimental data on UHDR water radiolysis. The model provides a robust, mechanistic foundation linking the physical parameter of dose rate to the distinct chemical environments that likely drive the differential biological outcomes of the FLASH effect. It serves as a powerful new tool for investigating the complex interplay between dose rate, oxygenation, and radiolytic chemistry.

This study investigates wear mechanisms of coated shafts in journal bearings within liquid lead-bismuth eutectic. Shafts were coated with TiAlN, a-C:H, multi-layer TiAlN with sputtered carbon, and chrome plating. Bearings made from sintered iron with carbon inclusions (DEVA 120 and DEVA 121) were tested in LBE at 200°C and 50rpm using a dedicated test rig. The a-C:H coatings failed due to tribofilm wear with DEVA 120, while TiAlN coatings failed from fatigue wear with DEVA 120 but succeeded with DEVA 121. Chrome-plated shafts experienced abrasive and adhesive wear with DEVA 121 but survived DEVA 120 due to transfer layer formation. The study highlights the need to understand wear mechanisms and material compatibility to develop durable coatings for harsh environments.

The deposition of functional coatings by Physical Vapor Deposition (PVD) on open-cell 3D foams represents a burgeoning area within material science, especially for electrochemical applications. Due to the novelty of this field and the unique geometry of the foams, the use of PVD on these substrates is a breakthrough innovation for functional material development. However, several challenges remain, e.g. understanding film growth mechanisms on foams, their impact on electrochemical processes, and optimizing the performance of coated foams across various applications through an understanding of the electrochemical phenomena occurring inside and on the surface of the coated foams. This review provides the first thorough overview of the current state-of-the-art in this area and suggests innovative solutions to the challenges encountered. It reports the various properties of films on foams reported in literature, compares the electrochemical performance of PVD-coated foams for Oxygen Evolution Reaction (OER)/Hydrogen Evolution Reaction (HER) catalysis, and energy storage applications, and discusses the mechanisms that explain their performance. Additionally, the review offers an analysis of existing research and introduces a novel numerical methodology, integrating Direct Simulation Monte Carlo (DSMC), Particle-in-Cell Monte Carlo (PICMC), and kinetic Monte Carlo (kMC) techniques to facilitate the characterization of coatings within the foams.

This work presents an original method to deposit dense, hard and amorphous silicon carbide (SiC) coatings with excellent thermal stability and slow oxidation (activation energy of 113 +/- 13 kJ/mol, passive oxide layer of 340 nm and no crystallization after air annealing at 900 degrees C during 62 h). The novelty lies in the use of alloy target to straightforward synthesize SiC coating, using non-reactive DC magnetron sputtering process, carried out without substrate heating. The coatings demonstrate notable mechanical properties, with a hardness of 56.4 GPa and a reduced modulus of 342 GPa, as measured by nano-indentation, and excellent adhesion even with mu m-thick coating. The chemistry, structure, and morphology of the coatings were analysed using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) to confirm their thermal and structural stability upon annealing. Additionally, a method combining XPS and SEM was applied to determine the activation energy for thermal annealing in air, across a temperature range of 600 degrees C to 1100 degrees C. The coatings exhibit excellent oxidation resistance, superior to those produced by other more complex methods, highlighting the efficiency of this simple fabrication approach.

The precise determination of viral titers in virological studies is a critical step to assess the infectious viral concentration of a sample. Although conventional titration methods, such as endpoint dilution or plaque forming units are the gold standards, their widespread use for screening experiments remains limited due to the time-consuming aspect and resource-intensive requirements. This study introduces a rapid and user-friendly high-throughput screening assay for evaluating viral titers. The colorimetric method used relies upon assessing virus-induced cytopathic effects by measuring the reduction of a tetrazolium reagent to formazan through cellular dehydrogenation within mitochondria. The resulting formazan quantity is correlated with the viral titer and can be easily quantified by a colorimetric measurement. In this perspective, this manuscript describes two case studies for the titration of the porcine respiratory coronavirus virus and bovine alpha herpesvirus 1, highlighting, respectively, a linear regime between 100 and 2000 TCID50/ml and 500- 10 6 PFU/ml for rapid titration within these ranges. The proposed technique's advantages and drawbacks are discussed, along with potential applications such as drug screening and the assessment of viral survival on inert surfaces.

The quaternary TixAlyTazN system has demonstrated superior thin film properties compared to conventional TixAlyN coatings. Beyond the influence of Ta content, the deposition method plays a crucial role in determining the structural and mechanical characteristics of the films. In this work, high-power impulse magnetron sputtering (HiPIMS) was used to deposit dense, tough, and hard TixAlyTazN coatings with different compositions from composite targets. These coatings were compared with TiAlN films. The impact of Ta incorporation was investigated both experimentally and through numerical simulations. Thin film growth and composition were modeled using VirtualCoaterTM, which provided valuable insights into the role of Ta in enhancing film densification and clarified the link between target and film compositions. Subsequent experimental characterization of mechanical, structural, and thermal properties revealed the significant advantages conferred by Ta addition. The improvements are attributed to: (1) enhanced hardness due to densification induced by energetic Ta ion bombardment, (2) stabilization of the cubic phase at elevated temperatures, and (3) improved thermal resistance through the formation of a homogeneous (TixAlyTaz) oxide layer, in contrast to the Al2O3/TiO2 bilayer typically observed in TiAlN coatings, as confirmed by XPS depth profiling. Finally, dry cutting tests confirmed a marked increase in tool life and improved surface finish of the machined components.

Understanding the growth mechanisms of metallic silver nanoparticles is crucial for optimizing their use in advanced optical applications, such as plasmonic devices and sensors. This study examined the growth of silver nanoparticles deposited by DC magnetron sputtering, focusing on the effects of deposition pressure, substrate material, and sample temperature. Multilayer plasmonic stacks were analyzed using techniques such as X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and transmission electron microscopy (TEM) with energy dispersive X-ray spectroscopy (EDS). These characterizations are supported by finite-difference timedomain (FDTD) simulations to model and compare the optical response with experimentally obtained spectra. The results demonstrate the influence of deposition conditions on nanoparticle distribution, shape, and optical properties, offering insights and simulation tools for optimizing large-area plasmonic systems.

Radiobiology relies on animal studies to demonstrate efficacy and safety of treatments. For proton-based studies in clinical settings, bespoke solutions, enabling animal irradiations without compromising health and safety regulations, need to be developed to facilitate the research. This study aims to demonstrate the usability of the IRRAMICE, a novel system with bespoke collimators to effectively treat small targets, within proton clinical facilities. Following a clinical workflow of planning CT, treatment plan design and delivery, a dosimetric evaluation of the IRRAMICE was conducted. Traceable absorbed dose was determined by measurements with (i) ion chamber, (ii) alanine pellets within a mouse phantom and a bespoke holder in the IRRAMICE, and (iii) Gafchromic film in the holder for a relative evaluation of the collimation system. Dose determined with alanine pellets in the mouse phantom were within 2% of the planned dose. The 2%/2 mm local gamma analysis of the dose distribution of the collimated beam spot determined by the film and the treatment planning system showed an average 98.3% passing rate. Through measurements in mouse phantoms, IRRAMICE demonstrated to be a suitable device for enabling the setup and delivery of treatment plans in a reliable and reproducible manner, to facilitate in vivo preclinical experiments.

Amorphous alumina is hard but brittle like all ceramic type materials which affects durability under impact or scratch. Here we show that alumina layers below 100 nm thickness when stacked with aluminum interlayers exhibit exceptional performances including toughness equal to 300 J.m−2 determined by on chip nanomechanics. This is almost two orders of magnitude higher than bulk alumina and higher than any other thin hard coatings. In addition, a hardness above 8 GPa combines with a fracture strain above 5%. The origin of this superior set of properties is unravelled via in-situ TEM and mechanical models. The combination of constrained alumina layers with ductile behavior, strong “accommodating” interfaces, giant shear deformability of Al layers, and plasticity-controlled crack shielding cooperate to stabilize deformation, dissipate energy and arrest cracks. These performances unlock several options of applications of Al2O3 in which brittleness under contacts prevents benefiting from remarkable functional properties and chemical stability. Alumina layers below 100 nm thickness stacked with aluminum interlayers combine exceptional properties including high toughness, strength and ductility. The origin of this optimal tryptic is unraveled by advanced nanomechanics and in-situ TEM.

The synthesis of functional material (e.g. TiO2) on foams is a becoming an important research area, particularly in photocatalysis. However, photocatalytic coatings on foams are most of the time synthesised using the sol-gel and soft template methods. PVD-based methods are rarely used to deposit photocatalytic coatings on such substrates and when they are, the growth mechanisms are never mentioned. However, PVD deposition can bring significant breakthroughs when using such 3D substrates, like accurate control and tuning of film morphology, composition, and/or synthesis of metastable phases.This work is a comprehensive study of the film growth on complex 3D substrates. TiO2 films have been deposited on Ni and C foams by magnetron sputtering in different discharge modes (DC transition regime, DC fully reactive, and HiPIMS) to understand the correlation between discharge parameters, covering of the foam, and photocatalytic performance of coated substrate. Depending on the choice of deposition parameters, the structure is tuned between anatase, or a mix of rutile and anatase, with the possibility to synthesise highly unstable {001} crystal facets. SEM cross-sections of the TiO2@C foam assemblies allow to observe the change in coating morphology with increasing depth inside the foam. The photoelectrochemical measurements, combined with the XRD results, highlight the superior photocurrent generation provided by the coatings deposited using DC magnetron sputtering in the transition regime, as they display a well-crystallised anatase structure with a large amount of highly photocatalytically active {001} facets.

Despite the widespread use of the finite-difference time-domain (FDTD) method for modeling plasmonic systems, there is a lack of detailed convergence and accuracy studies for periodic nanoparticle systems in which both particle radius and interparticle distance are critical parameters. Using an in-house parallelized 3D-FDTD code for which we implemented interface field averaging, convergence and accuracy were evaluated for various spherical particle radii, inter-distances, and radius-to-mesh size ratios. We found that Interface Field Averaging (IFA) FDTD improved accuracy and convergence with respect to per-component (Per-C) meshing. In the worst case of this study, the convergence error decreased from 4.9% to 2.6% only by using IFA. Accuracy was verified by benchmarking our simulation results with COMSOL Multiphysics software. Furthermore, we notice that there exists no general rule for choosing the mesh size. Careful convergence testing should therefore be carried out systematically.