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Machine learning-based classification approaches are widely used to predict host phenotypes from microbiome data. Classifiers are typically employed by considering operational taxonomic units or relative abundance profiles as input features. Such types of data are intrinsically sparse, which opens the opportunity to make predictions from the presence/absence rather than the relative abundance of microbial taxa. This also poses the question whether it is the presence rather than the abundance of particular taxa to be relevant for discrimination purposes, an aspect that has been so far overlooked in the literature. In this paper, we aim at filling this gap by performing a meta-analysis on 4,128 publicly available metagenomes associated with multiple case-control studies. At species-level taxonomic resolution, we show that it is the presence rather than the relative abundance of specific microbial taxa to be important when building classification models. Such findings are robust to the choice of the classifier and confirmed by statistical tests applied to identifying differentially abundant/present taxa. Results are further confirmed at coarser taxonomic resolutions and validated on 4,026 additional 16S rRNA samples coming from 30 public case-control studies.

The long-term stability of Pt-based catalysts is critical to the reliability of proton exchange membrane fuel cells (PEMFCs), and receives constant attention. However, the current knowledge of Pt oxidation is restricted to unrealistic PEMFC cathode environment or operation, which questions its practical relevance. Herein, Pt oxidation is investigated directly in a PEMFC with stroboscopic operando high energy X-ray scattering. The onset potential for phase transition of the nanoparticles surface from metallic to amorphous electrochemical oxide is observed far below previously reported values, and most importantly, below the open-circuit potential of PEMFC cathode. Such phase transition is shown to impact PEMFC performance and its role on Pt transient dissolution is verified by electrochemical on-line inductively coupled plasma mass spectrometry. By further demonstrating and resolving the limitations of currently employed accelerated stress test protocols in the light of metal-oxide phase transitions kinetics, this picture of Pt oxidation enables new mitigation strategies against PEMFC degradation. The stability of Pt-based catalysts is critical to the reliability of proton exchange membrane fuel cells. Here, the authors use stroboscopic operando high energy X-ray scattering to reveal Pt nanocatalysts experience a metal-oxide phase transition during conventional fuel cell operation.

Polyacrylonitrile (PAN) fibers are widely used as precursors in the manufacture of high-conducting and mechanically resistant carbon fibers. The modulation of such fibers is carried out through electrospinning. In this work, we show the production and control of the morphology of nanometric-range PAN fibers for their potential use as precursors for high-electrical-conductivity carbon fibers. PAN samples dissolved in dimethylformamide (DMF) were prepared at 6, 10, and 12% w/w, at 15 and 25 kV. The impact of the rotation of the collector drum at 100, 300, and 500 RPM was also studied. It was found that the percentage of PAN in the solution proportionally affects the diameter of the fibers and that the preparation potential affects the morphology. The rotation speed, when increased, decreases the diameter, and it has a negative impact on the morphology. Fibers prepared with 6% w/w at 15 kV and 500 RPM show 90 nm diameters, the smallest diameter of all the samples.

In this study, the resistance to corrosion of niobium-doped tin dioxide (Nb-doped SnO2, NTO) and antimony-doped tin oxide (Sb-doped SnO2, ATO) supports has been probed for proton-exchange membrane fuel cell (PEMFC) application. To achieve this goal, ATO or NTO supports with loose-tube (fiber-in-tube) morphology were synthesized using electrospinning and decorated with platinum (Pt) nanoparticles. These cathode catalysts were submitted to two different electrochemical tests, an accelerated stress test following the EU Harmonised Test Protocols for PEMFC in a single cell configuration and an 850 h test in real air-breathing PEMFC systems. In both cases, the dissolution of the doping element was measured either by inductively coupled plasma mass spectrometry (ICP–MS) performed on the exhaust water or by energy dispersive X-ray spectrometry (X-EDS) analysis on ultramicrotomed membrane electrode assembly (MEA), and correlated to the performance losses upon ageing. It appears that the NTO-based support leads to lower performances than the ATO-based one, mainly owing to the low electronic conductivity of NTO. However, in the case of ATO, dissolution of the Sb doping element is non-negligible and represents a major issue from a stability point-of-view.

Pt-based catalysts remain the most effective materials for the oxygen reduction reaction (ORR) at the cathode of proton exchange membrane fuel cells (PEMFCs); however, platinum scarcity and high cost severely limit the large-scale deployment of the technology. Improving catalytic activity and durability through precise control of nanoparticle morphology is therefore crucial for reducing costs and enhancing sustainability, enabling PEMFC widespread adoption. In this context, carbon-supported Pt-based nanoparticles with a 30 wt.% Pt loading were synthesized by an organometallic chemistry approach using hexadecylamine (HDA) as a stabilizer, allowing fine control over nanoparticle morphology. Two distinct synthesis pathways (one-pot and two-step procedures) were used to prepare platinum catalysts supported on KetjenBlack EC-300J (KB), and their influence on the electrocatalytic activity of the obtained nanomaterials was studied. Furthermore, the effect of HDA stabilization on catalyst performance was investigated. Directly synthesized Pt/KB catalysts exhibited similar ORR mass activity, regardless of whether or not HDA was present. Pt/KB prepared by the two-step procedure showed a significantly lower performance. Additionally, despite a larger loss of electrochemical surface area during an accelerated stress test compared to a commercial Pt/C reference, PtHDA/KB and Pt/KB catalysts maintained stable mass activity and limited specific activity degradation, highlighting the beneficial effect of nanoparticle stabilization in the presence of HDA on prolonged electrocatalyst cycling.

In this paper, an extensive characterisation of a range of carbon blacks (CB) with similar surface area but different surface chemistry is carried out by flow calorimetry, Raman spectroscopy, dynamic water vapour sorption, instrumental gas analysis, nitrogen adsorption/desorption and high potential chronoamperometry. Using these carbon materials as supports, Pt/CB electrocatalysts are prepared by microwave‐assisted polyol‐mediated synthesis in gram scale. Structural, morphological and electrochemical properties of the prepared electrocatalysts are evaluated by X‐ray diffraction, transmission electron microscopy, rotating disc electrode and in situ fuel cell characterisation of the corresponding membrane–electrode assemblies. The obtained results allow to establish a relationship between surface chemistry and electrochemical properties useful for the design of Pt/C catalyst layers with high performance and stability. Surface properties of carbon supports play a role in the electrochemical and durability characteristics of the corresponding electrocatalysts and catalyst layers: cathodes based on carbon blacks with hydrophobic character demonstrated improved oxygen reduction reaction activity, durability and mass transfer.

A Pt‐free cathode catalyst is necessary for proton‐exchange membrane fuel cell (PEMFC) to enable the widespread use of these environmentally friendly energy conversion devices at affordable price. Herein, a pyrolyzed electrospun carbon nanofibre (CNF) catalyst is prepared embedded with cobalt(II) phthalocyanine and iron(II) phthalocyanine compounds to provide the transition metal N4‐macrocyclic complex‐derived sites (MNX) possessing better electrocatalytic oxygen reduction reaction (ORR) activity. The physical characterisation showed the nanofibrous structure of catalyst with rough surface texture and considerable amount of N, Fe, and Co. The D−MN4−CNF−IL−A catalyst prepared using ionic liquid as a porogen displayed the best electrocatalytic activity for O2 electroreduction proceeding via 4e− pathway in 0.5 M H2SO4 electrolyte solution with the ORR onset and half‐wave potential of 0.83 and 0.71 V vs reversible hydrogen electrode (RHE), respectively. Iron and cobalt phthalocyanine embedded electrospun carbon nanofiber‐based oxygen reduction reaction (ORR) catalysts were prepared in this investigation by combined approach of pyrolysis and acid leaching. The catalyst exhibited the ORR half‐wave potential of 0.71 V vs reversible hydrogen electrode (RHE) in 0.5 M H2SO4 electrolyte solution.

Usutu virus (USUV) is an emerging mosquito-borne flavivirus closely related to West Nile virus (WNV), sharing ecological niches and transmission cycles involving Culex mosquitoes and wild birds. In Italy, USUV was first detected in 1996 and has become endemic in northern regions, whereas, to date, no cases have been reported in southern Italy. In August 2025, a yellow-legged gull ( Larus michahellis ) from the provinces of Salerno for passive surveillance and a Eurasian jay ( Garrulus glandarius ) during active surveillance from Caserta (southern Italy), were examined. Heart, spleen, kidney, and brain tissues were collected for virological investigation. Real-time RT-PCR assays targeting West Nile virus and Usutu virus were performed and USUV RNA was detected in both avian specimens, while samples tested negative for WNV. Next, entomological surveillance was conducted on both sites and a mosquito pool collected near the yellow-legged gull carcass tested positive. Positive samples were subjected to Sanger sequencing of the NS5 gene. BLAST and phylogenetic analyses revealed strain belonged to lineage Europe 2, sub-group 2-A showing 99.6% nucleotide identity with northern Italian strains circulating between 2018 and 2023 and 99.8% identity with northern European strains circulating between 2016 and 2024. These findings suggest two possible scenarios: local southward spread of an autochthonous Italian strain or a recent introduction from other European countries mediated by migratory wild birds. This study provides the first molecular evidence of USUV circulation in southern Italy and underscores the critical role of molecular epidemiology and phylogenetic analysis in tracing routes of pathogen introduction and spread.

The wide deployment of fuel cells in transportation applications necessitates efficiency, lifetime, and cost improvements. Now, grooved electrodes with controlled design and composition address the limitations of conventional flat electrode structures, yielding improved fuel cell performance.

We performed a longitudinal shotgun metagenomic investigation of the plaque microbiome associated with peri-implant diseases in a cohort of 91 subjects with 320 quality-controlled metagenomes. Through recently improved taxonomic profiling methods, we identified the most discriminative species between healthy and diseased subjects at baseline, evaluated their change over time, and provided evidence that clinical treatment had a positive effect on plaque microbiome composition in patients affected by mucositis and peri-implantitis.