Engineering (Italy)

A palladium-catalyzed (3+2) cycloaddition between arylalkynes and norbornene derivatives via C-H bond cleavage is reported. This reaction enables the selective synthesis of benzo-fused five-membered cyclic products from a variety of arylalkynes, including electronically biased and alkyl(aryl)alkynes. Notably, the use of a bulky bidentate ligand leads to the (2+2) cycloaddition, giving four-membered cyclobutene derivatives from the same starting materials. Mechanistic studies indicate that both cycloadditions proceeds through hydropalladation of the arylalkynes by Pd(0) and AcOH to generate a vinyl-Pd intermediate. DFT calculations suggest a ligand-to-ligand hydrogen transfer (LLHT) mechanism for this step. The subsequent turnover-determining step is proposed to vary with the ligand environment, involving either the C-H bond cleavage or reductive elimination, thereby governing pathway selectivity.

The Metaproteomics Initiative was officially launched in 2021 to strengthen collaboration, promote knowledge exchange, and support and lead standardization efforts within the growing metaproteomics community. Over the past five years, the Initiative has developed into a structured, global network of researchers. It has launched community-driven benchmark studies, helped shape emerging metadata and reporting standards, developed practical guidance and training materials, organized international symposia, and fostered connections across the microbiome research landscape (https://metaproteomics.org/). We outline the Initiative's organization, activities, achievements, and ongoing efforts, and reflect on how sustained, community-led coordination has shaped the development of metaproteomics as a field. We further position the Grand Metaproteome Challenges as a next step toward coordinated, community-scale biological research, aimed at advancing functional microbiome studies across clinical, industrial, and environmental application domains, and invite engagement from the wider microbiome and omics communities.

In this study, graphdiyne (GDY) was grown in situ on sulfide surfaces derived from polyoxometalate (POM) to construct sp-C–S–M heterointerfaces between metal sulfides (Fe3S4 and MoS2) and GDY, thereby enabling highly efficient bifunctional oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) electrocatalysis. Experimental results reveal that the heterointerface configuration enhances the synergistic interaction between the POM-derived sulfides and GDY, promoting rapid charge transfer and increasing the number of active sites, which collectively boost the intrinsic catalytic activity. At a current density of 10 mA cm–2, the catalyst demonstrates low overpotentials of 132 mV for the HER and 218 mV for the OER and exhibits excellent catalytic activity. This work systematically clarifies the critical roles of electronic interaction and interfacial architecture between POM-derived components and GDY in enhancing HER and OER activities, offering an effective strategy for the design and construction of high-performance electrocatalysts.

Early prediction of remnant liver growth after portal vein embolization (PVE) would enable earlier surgery in patients with resectable liver malignancy, decreasing the risk of tumor progression. This study aims to demonstrate the feasibility of 4D flow MRI to detect changes in portal blood flow before and after PVE and determine whether 4D flow MRI can predict hypertrophy of nonembolized liver lobes (future liver remnant) in a porcine model. Thirteen juvenile pigs were included in this prospective study. In 11 pigs, 2 of the 4 portal vein branches were selectively embolized using polyvinyl alcohol particles. Two pigs served as controls. All animals were imaged before, 1 hour, and 1 and 2 weeks after PVE using 4D flow and T1-weighted 3D spoiled gradient-echo MRI. Flow measurements were correlated with liver volumetry measurements. The predictive value of flow changes immediately after PVE for future liver remnant hypertrophy at 2 weeks was estimated using linear mixed-effect model analysis. Twelve pigs completed the study. One treatment pig died from complications of anesthesia. Immediately after PVE, relative flow in the 2 embolized portal vein branches decreased from 17.0±2.1% to 3.4±2.1% of total portal flow, respectively. Relative flow increased from 16.6±3.8% to 32.6±3.8% in the remaining 2 nonembolized portal vein branches supplying the future liver remnant. Each 1% increase in relative blood flow directly after the procedure predicted a 4.8±0.7cm 3 (estimate±SE) increase in volume of the future liver remnant at 2 weeks ( P <0.0001). Conversely, in embolized lobes, each 1% flow decrease predicted a volume reduction of 3.4±1.0cm 3 ( P =0.003). 4D flow MRI successfully quantified portal blood flow before and after portal vein embolization in a porcine model. Notably, immediate postembolization changes in portal flow were predictive of lobar volume changes observed at 2 weeks. This porcine model thus provides a valuable platform for investigating the relationship between portal hemodynamics and hypertrophy of the future liver remnant. Furthermore, it will enable systematic evaluation of various embolization agents and techniques, supporting the refinement of interventional strategies in hepatic regenerative research.

This study investigates the influence of electromagnetic field polarization in the non-destructive testing of reinforced concrete structures through both theoretical analysis and experimental validation. Theoretical models predict that the orientation of reinforcement bars relative to the incident electric field significantly affects the scattered signal, influencing their detectability. Laboratory experiments on realistic reinforced concrete specimens presenting both vertical bars and horizontal brackets confirm these predictions, demonstrating that polarization can be exploited to enhance measurement accuracy. These findings provide useful insights into the development of microwave-based diagnostic techniques for structural assessment.

Bicontinuous polyHIPEs (PHs) containing imidazole groups as organocatalysts were prepared for the first time. The imidazole-bearing polymer, acting as an amine catalyst, failed to promote the Henry (nitroaldol) reaction between 4-nitrobenzaldehyde (4-NB) and nitromethane (NM) in organic solvents, including neat NM. Imidazole acted as a weak Lewis base and catalyzed the reaction only in water. To overcome this limitation, hydrogen-bond donor (HBD) groups were introduced into both phases of the high internal phase emulsions (HIPEs) to enable cooperative catalysis. This strategy enabled high catalytic conversion with 100% product selectivity in the Henry reaction and effective site isolation through the HIPE phases. The hydroxyl groups acted as strong HBDs, facilitating cooperative catalysis and leading to high conversions in methanol, dimethylformamide (DMF), and dimethyl sulfoxide (DMSO). In a control reaction, a bicontinuous polyHIPE bearing imidazole and benzyl chloride groups efficiently catalyzed the acetalization reaction in methanol, achieving very high conversions within a short reaction time. We hypothesize that the methylene chloride pendant group acted as a HBD, activating the carbonyl group of 4-NB via the −C–H···O interaction, yielding only acetal. The heterogeneous catalyst cooperatively catalyzed the formation of the acetal in methanol with a high conversion rate of 95%. In contrast, a polyHIPE synthesized using only vinylbenzyl chloride (VBC) exhibited low activity, suggesting that the presence of the amine group played a crucial cooperative role in the acetalization reaction, supporting the conclusion that the amine group is actively involved in the catalytic process. Although the methylene chloride pendant group is not a conventional hydrogen bond donor and is considered a very weak one, it enabled dominant solvent–solvent interactions in methanol that allowed this weak HBD to effectively activate 4-NB, contributing to the overall catalytic performance. The study also explored how the identity and the amine/HBDs affected catalytic performance.

Producing clean hydrogen fuel in quantities sufficient to meet the energy needs most reliant on fossil fuels is a critical step toward transitioning to net-zero emissions. Upscaling hydrogen production is closely linked to improving the stability, efficiency, and reliability of water splitting technologies. Nanoscale material platforms, engineered to maximize surface area and integrate complex surface chemistry, can significantly enhance the rate of hydrogen production in systems used in electrochemistry, catalysis, and materials science, driving innovations in energy storage and conversion technologies. However, with the rapid emergence of increasingly complex material architectures, selecting the most effective design for water splitting and hydrogen evolution systems remains a challenge. This article explores whether the shape and dimension of carbon-based nanoarchitectures are key factors in the rational design of materials for these applications. We examine how different structural forms, ranging from zero-dimensional quantum dots to one-, two-, and three-dimensional architectures, affect water splitting and hydrogen evolution mechanisms. Focusing on the latest advancements in carbon-based metamaterials and hierarchical nanoarchitectures, we evaluate their potential impact and highlight the challenges involved. We also summarize the current state of knowledge and discuss future directions for the development of carbon-based nanoarchitectures that could provide breakthroughs in hydrogen production.

Railway infrastructure earthwork is subjected to traffic-induced cyclic loads, which can be particularly challenging when constructed on weak or problematic soils. To enhance the engineering properties of such soils, various soil improvement techniques, including the use of cement and lime, have been widely applied. However, these conventional methods raise environmental concerns due to their contribution to greenhouse gas emissions. As a result, there is a growing need to explore eco-friendly ground improvement alternatives. This study investigates the use of biochar as a sustainable soil reinforcement material. The shear behaviour of both unreinforced and biochar-amended soil was assessed through direct shear tests and triaxial (static and cyclic) tests. Direct shear test results showed that adding 5% biochar notably improved the soil's cohesion and internal friction angle, optimising the balance between particle interlocking and porosity. However, increasing the biochar content to 10% led to a 32.4% reduction in the internal friction angle. Static triaxial tests demonstrated that biochar reinforcement improved deviator stress and accelerated pore water dissipation compared to unreinforced soil. Meanwhile, cyclic triaxial tests revealed that higher biochar content resulted in increased accumulated axial strain and excess pore water pressure. Additionally, scanning electron microscopy analyses examined the interaction between soil and biochar particles. The findings highlight biochar's potential as a sustainable, eco-friendly soil reinforcement for enhancing ground stability in railway constructions and other geotechnical applications.

The dispersion coefficient of the constant phase element (CPE) is typically treated as an empirical fitting parameter in the analysis of impedance spectroscopy data, with no clear physical meaning. Here, we present an energy-based interpretation for this coefficient by linking it to the ratio of the dissipated or stored energy in the CPE relative to that supplied by the input source. Using the RC network equivalency of a CPE, we decompose the total input energy into a contribution stored in the capacitive modes and another dissipated in the resistive modes. Analytical expressions of these energy quantities are derived for three test examples: (i) a constant voltage, (ii) a voltage ramp, and (iii) a quadratic input of the form v(t) = λt2. In all cases, we found that the ratios of any two of these energy quantities reduce to pure functions of the dispersion coefficient of the CPE, independent of excitation amplitude or material parameters. This result provides a new perspective on the CPE’s dispersion coefficient from a thermodynamic/energetic basis, with direct implications for supercapacitor characterization, battery modeling, as well as for the analysis of other electrochemical devices and systems exhibiting the CPE behavior.

The top-seeded solution growth (TSSG) method is a promising technique for growing high-quality silicon carbide (SiC) single crystals. However, the inherently low carbon solubility in the Si–C system limits its growth efficiency. In this study, neodymium (Nd) was introduced as a solvent additive to enhance carbon solubility and enable the efficient low-temperature growth of SiC single crystals at 1823 K. A 2D axisymmetric numerical model based on CGSim was developed to investigate heat conduction, convection, mass transport, and interfacial reactions. The effects of varying Nd concentrations on the temperature field, melt flow structure, carbon transport pathways, and supersaturation distribution were systematically analyzed. Experimentally, SiC single crystals were successfully grown at 1823 K using induction heating TSSG, and their morphology, orientation, and quality were characterized via SEM and EBSD. The experimental results were in good agreement with the simulations. This work is the first to demonstrate the growth of high-quality SiC single crystals from a Si–Nd–C solution at 1823 K. The results confirm that the addition of Nd significantly increases carbon solubility in the melt, facilitates effective carbon transport and uniform deposition, and thus promotes controlled crystal growth under low-temperature conditions. Furthermore, the optimal Nd concentration range for SiC single-crystal growth was identified as 15–25 mol %. Among them, 15 mol % Nd is favorable for achieving stable and uniform high-quality crystals, while 25 mol % Nd provides an efficient solution environment for rapid crystal growth.