The Role of Substrate Surface Geometry in the Photo-Electrochemical Behaviour of Supported TiO2 Nanotube Arrays: A Study Using Electrochemical Impedance Spectroscopy (EIS).

Highly ordered TiO2 nanotube (NT) arrays grown on Ti mesh and Ti foil were successfully prepared by a controlled anodic oxidation process and tested for water photo-electrolysis. Electrochemical impedance spectroscopy (EIS), combined with other electrochemical techniques (cyclic voltammetry and chronoamperometry) in tests performed in the dark and under illumination conditions, was used to correlate the photoactivity to the specific charge transfer resistances associated with a 3D (mesh) or 2D (foil) geometry of the support. The peculiar structure of the nanotubes in the mesh (with better light absorption and faster electron transport along the nanotubes) strongly impacts the catalytic performances under illumination. H2 production and current density in water photo-electrolysis were over three times higher with the TiO2NTs/Ti mesh, compared to the foil in the same conditions. The results obtained by the EIS technique, used here for the first time to directly compare TiO2 nanotubes on two different supports (Ti foil and Ti mesh), led to a better understanding of the electronic properties of TiO2 nanotubes and the effect of a specific support on its photocatalytic properties.

Influence of Excess Charge on Water Adsorption on the BiVO4(010) Surface.

We present a combined computational and experimental study of the adsorption of water on the Mo-doped BiVO4(010) surface, revealing how excess electrons influence the dissociation of water and lead to hydroxyl-induced alterations of the surface electronic structure. By comparing ambient pressure resonant photoemission spectroscopy (AP-ResPES) measurements with the results of first-principles calculations, we show that the dissociation of water on the stoichiometric Mo-doped BiVO4(010) surface stabilizes the formation of a small electron polaron on the VO4 tetrahedral site and leads to an enhanced concentration of localized electronic charge at the surface. Our calculations demonstrate that the dissociated water accounts for the enhanced V4+ signal observed in ambient pressure X-ray photoelectron spectroscopy and the enhanced signal of a small electron polaron inter-band state observed in AP-ResPES measurements. For ternary oxide surfaces, which may contain oxygen vacancies in addition to other electron-donating dopants, our study reveals the importance of defects in altering the surface reactivity toward water and the concomitant water-induced modifications to the electronic structure.

Quantification of the Activator and Sensitizer Ion Distributions in NaYF4 :Yb3+ , Er3+ Upconverting Nanoparticles Via Depth-Profiling with Tender X-Ray Photoemission.

The spatial distribution and concentration of lanthanide activator and sensitizer dopant ions are of key importance for the luminescence color and efficiency of upconverting nanoparticles (UCNPs). Quantifying dopant ion distributions and intermixing, and correlating them with synthesis methods require suitable analytical techniques. Here, X-ray photoelectron spectroscopy depth-profiling with tender X-rays (2000-6000 eV), providing probe depths ideally matched to UCNP sizes, is used to measure the depth-dependent concentration ratios of Er3+ to Yb3+ , [Er3+ ]/[Yb3+ ], in three types of UCNPs prepared using different reagents and synthesis methods. This is combined with data simulations and inductively coupled plasma-optical emission spectroscopy (ICP-OES) measurements of the lanthanide ion concentrations to construct models of the UCNPs' dopant ion distributions. The UCNP sizes and architectures are chosen to demonstrate the potential of this approach. Core-only UCNPs synthesized with XCl3 ·6H2 O precursors (ß-phase) exhibit a homogeneous distribution of lanthanide ions, but a slightly surface-enhanced [Er3+ ]/[Yb3+ ] is observed for UCNPs prepared with trifluroacetate precursors (α-phase). Examination of Yb-core@Er-shell UCNPs reveals a co-doped, intermixed region between the single-doped core and shell. The impact of these different dopant ion distributions on the UCNP's optical properties is discussed to highlight their importance for UCNP functionality and the design of efficient UCNPs.

Subsurface oxide plays a critical role in CO2 activation by Cu(111) surfaces to form chemisorbed CO2, the first step in reduction of CO2.

A national priority is to convert CO2 into high-value chemical products such as liquid fuels. Because current electrocatalysts are not adequate, we aim to discover new catalysts by obtaining a detailed understanding of the initial steps of CO2 electroreduction on copper surfaces, the best current catalysts. Using ambient pressure X-ray photoelectron spectroscopy interpreted with quantum mechanical prediction of the structures and free energies, we show that the presence of a thin suboxide structure below the copper surface is essential to bind the CO2 in the physisorbed configuration at 298 K, and we show that this suboxide is essential for converting to the chemisorbed CO2 in the presence of water as the first step toward CO2 reduction products such as formate and CO. This optimum suboxide leads to both neutral and charged Cu surface sites, providing fresh insights into how to design improved carbon dioxide reduction catalysts.

A multifunctional biphasic water splitting catalyst tailored for integration with high-performance semiconductor photoanodes.

Artificial photosystems are advanced by the development of conformal catalytic materials that promote desired chemical transformations, while also maintaining stability and minimizing parasitic light absorption for integration on surfaces of semiconductor light absorbers. Here, we demonstrate that multifunctional, nanoscale catalysts that enable high-performance photoelectrochemical energy conversion can be engineered by plasma-enhanced atomic layer deposition. The collective properties of tailored Co3O4/Co(OH)2 thin films simultaneously provide high activity for water splitting, permit efficient interfacial charge transport from semiconductor substrates, and enhance durability of chemically sensitive interfaces. These films comprise compact and continuous nanocrystalline Co3O4 spinel that is impervious to phase transformation and impermeable to ions, thereby providing effective protection of the underlying substrate. Moreover, a secondary phase of structurally disordered and chemically labile Co(OH)2 is introduced to ensure a high concentration of catalytically active sites. Application of this coating to photovoltaic p+n-Si junctions yields best reported performance characteristics for crystalline Si photoanodes.

Understanding the Oxygen Evolution Reaction Mechanism on CoOx using Operando Ambient-Pressure X-ray Photoelectron Spectroscopy.

Photoelectrochemical water splitting is a promising approach for renewable production of hydrogen from solar energy and requires interfacing advanced water-splitting catalysts with semiconductors. Understanding the mechanism of function of such electrocatalysts at the atomic scale and under realistic working conditions is a challenging, yet important, task for advancing efficient and stable function. This is particularly true for the case of oxygen evolution catalysts and, here, we study a highly active Co3O4/Co(OH)2 biphasic electrocatalyst on Si by means of operando ambient-pressure X-ray photoelectron spectroscopy performed at the solid/liquid electrified interface. Spectral simulation and multiplet fitting reveal that the catalyst undergoes chemical-structural transformations as a function of the applied anodic potential, with complete conversion of the Co(OH)2 and partial conversion of the spinel Co3O4 phases to CoO(OH) under precatalytic electrochemical conditions. Furthermore, we observe new spectral features in both Co 2p and O 1s core-level regions to emerge under oxygen evolution reaction conditions on CoO(OH). The operando photoelectron spectra support assignment of these newly observed features to highly active Co4+ centers under catalytic conditions. Comparison of these results to those from a pure phase spinel Co3O4 catalyst supports this interpretation and reveals that the presence of Co(OH)2 enhances catalytic activity by promoting transformations to CoO(OH). The direct investigation of electrified interfaces presented in this work can be extended to different materials under realistic catalytic conditions, thereby providing a powerful tool for mechanism discovery and an enabling capability for catalyst design.

Fabrication of Ti substrate grain dependent C/TiO2 composites through carbothermal treatment of anodic TiO2.

Composite materials of titania and graphitic carbon, and their optimized synthesis are highly interesting for application in sustainable energy conversion and storage. We report on planar C/TiO2 composite films that are prepared on a polycrystalline titanium substrate by carbothermal treatment of compact anodic TiO2 with acetylene. This thin film material allows for the study of functional properties of C/TiO2 as a function of chemical composition and structure. The chemical and structural properties of the composite on top of individual Ti substrate grains are examined by scanning photoelectron microscopy and micro-Raman spectroscopy. Through comparison of these data with electron backscatter diffraction, it is found that the amount of generated carbon and the grade of anodic film crystallinity correlate with the crystallographic orientation of the Ti substrate grains. On top of Ti grains with ∼(0001) orientations the anodic TiO2 exhibits the highest grade of crystallinity, and the composite contains the highest fraction of graphitic carbon compared to Ti grains with other orientations. This indirect effect of the Ti substrate grain orientation yields new insights into the activity of TiO2 towards the decomposition of carbon precursors.

Multiplex real-time PCR probe-based for identification of strains producing: OXA48, VIM, KPC and NDM.

The spread of multi-resistant enterobacteria, particularly carbapenem-resistant Enterobacteriaceae (CRE), in both community and hospital settings is a global problem. The phenotypic identification of CRE is complex, occasionally inconclusive and time consuming. However, commercially available molecular assays are very expensive, and many do not allow the simultaneous identification of all genetic markers of resistance that have been recognised in CRE (bla KPC, bla OXA-48, bla VIM and bla NDM). The aim of the present study is to describe a new test: a multiplex real time PCR probe-based assay designed for the simultaneous detection of KPC, OXA-48, VIM and NDM in a short time (no longer than 90 min from the extraction of DNA to detection). Our assay correctly identified 63 CRE isolates and all standard reference strains tested, in agreement with and extending the results of phenotypic identification tests; additionally, a KPC-VIM co-expressing Enterobacter aerogenes isolate was identified using the new assay, whereas traditional methods failed to detect it. The assay was also able to correctly detect 28 CRE-producers from 50 positive blood cultures, again detecting, in four specimens, the presence of CRE co-expressing KPC and VIM, which were only partially identified by traditional methods. Finally, when used directly on rectal swabs, the assay enabled the identification of CRE-carrier patients, for whom isolation is mandatory in a hospital setting.

Updates on Hydrogen Value Chain: A Strategic Roadmap.

A strategic roadmap for noncarbonized fuels is a global priority, and the reduction of carbon dioxide emissions is a key focus of the Paris Agreement to mitigate the effects of rising temperatures. In this context, hydrogen is a promising noncarbonized fuel, but the pace of its implementation will depend on the engineering advancements made at each step of its value chain. To accelerate its adoption, various applications of hydrogen across industries, transport, power, and building sectors have been identified, where it can be used as a feedstock, fuel, or energy carrier and storage. However, widespread usage of hydrogen will depend on its political, industrial, and social acceptance. It is essential to carefully assess the hydrogen value chain and compare it with existing solar technologies. The major challenge to widespread adoption of hydrogen is its cost as outlined in the roadmap for hydrogen. It needs to be produced at the levelized cost of hydrogen of less than $2 kg-1 to be competitive with the established process of steam methane reforming. Therefore, this review provides a comprehensive analysis of each step of the hydrogen value chain, outlining both the current challenges and recent advances.

Electrolyte selection toward efficient photoelectrochemical glycerol oxidation on BiVO4.

Glycerol, a primary by-product of biodiesel production, can be oxidized into various value-added chemicals, significantly enhancing the techno-economic value of photoelectrochemical (PEC) cells. Several studies have explored various photoelectrode materials and co-catalysts, but the influence of electrolytes on PEC glycerol oxidation has remained relatively unexplored despite its significance. Here, we explore the impact of various acidic (pH = 2) electrolytes, namely NaNO3, NaClO4, Na2SO4, K2SO4, and KPi, on PEC glycerol oxidation using nanoporous thin film BiVO4 as a model photoanode. Our experimental findings reveal that the choice of electrolyte anion and cation significantly affects the PEC performance (i.e., photocurrent, onset potential, stability, and selectivity towards value-added products) of BiVO4 for glycerol oxidation. To explain this interesting phenomenon, we correlate the observed performance trend with the ion specificity in the Hofmeister series as well as the buffering capacity of the electrolytes. Notably, NaNO3 is identified as the optimal electrolyte for PEC glycerol oxidation with BiVO4 when considering various factors such as stability and production rates for glycerol oxidation reaction (GOR) products, surpassing the previously favored Na2SO4. Glycolaldehyde emerges as the most dominant product with ∼50% selectivity in NaNO3. The general applicability of our findings is confirmed by similar observation in electrochemical (EC) GOR with a polycrystalline platinum anode. Overall, these results emphasize the critical role of electrolyte selection in enhancing the efficiency of EC/PEC glycerol oxidation.

Stephanoascus ciferrii Complex: The Current State of Infections and Drug Resistance in Humans.

In recent years, the incidence of fungal infections in humans has increased dramatically, accompanied by an expansion in the number of species implicated as etiological agents, especially environmental fungi never involved before in human infection. Among fungal pathogens, Candida species are the most common opportunistic fungi that can cause local and systemic infections, especially in immunocompromised individuals. Candida albicans (C. albicans) is the most common causative agent of mucosal and healthcare-associated systemic infections. However, during recent decades, there has been a worrying increase in the number of emerging multi-drug-resistant non-albicans Candida (NAC) species, i.e., C. glabrata, C. parapsilosis, C. tropicalis, C. krusei, C. auris, and C. ciferrii. In particular, Candida ciferrii, also known as Stephanoascus ciferrii or Trichomonascus ciferrii, is a heterothallic ascomycete yeast-like fungus that has received attention in recent decades as a cause of local and systemic fungal diseases. Today, the new definition of the S. ciferrii complex, which consists of S. ciferrii, Candida allociferrii, and Candida mucifera, was proposed after sequencing the 18S rRNA gene. Currently, the S. ciferrii complex is mostly associated with non-severe ear and eye infections, although a few cases of severe candidemia have been reported in immunocompromised individuals. Low susceptibility to currently available antifungal drugs is a rising concern, especially in NAC species. In this regard, a high rate of resistance to azoles and more recently also to echinocandins has emerged in the S. ciferrii complex. This review focuses on epidemiological, biological, and clinical aspects of the S. ciferrii complex, including its pathogenicity and drug resistance.

An atypical, pigment-producing Metschnikowia strain from a leukaemia patient.

A yeast strain was isolated from the sputum sample of a leukaemia patient in the Spirito Santo Hospital of Pescara, Italy. The fungus produced a pigment that formed a reddish halo around colonies, and was identified and deposited as a Metschnikowia spp. (accession number IHEM 25107-GenBank accession number JQ921016) in the BCCM/IHEM collection of biomedical fungi and yeasts (Bruxelles, Belgium). Although the physiology of the strain was close to that of Metschnikowia sinensis, the D1/D2 sequence did not correspond to any previously described Metschnikowia species. Phylogeny of the genus Metschnikowia is complex and requires far more analysis. We present the first non-M. pulcherrima Metschnikowia spp. isolate recovered from a human, and emphasize the role of man as a transient carrier of environmental yeasts, the pathogenicity of which still needs to be defined.

Palladium nanoparticles supported on nitrogen-doped HOPG: a surface science and electrochemical study.

We have investigated by photoemission spectroscopy and scanning tunnelling microscopy what are the chemical and structural changes induced by nitrogen ion implantation (500 eV) on highly oriented pyrolytic graphite and how the defects induced by this process modify the growth and thermal stability of palladium nanoparticles, deposited in situ by physical vapour deposition. Since nitrogen derived defects are mostly buried below the surface, they are not accessible for a chemical interaction with metal nanoparticles; however, the amorphization induced by the ion beam in the outermost layers of the substrate beneficially affects the metal morphology, limiting the size of the nanoparticles and improving their thermal stability. The supported nanoparticles have been tested towards the oxygen reduction reaction indicating that the electrochemical activity does not depend significantly on the ion implantation, but mostly on the amount of palladium.

Dynamical diagnostic of extreme events in Venice lagoon and their mitigation with the MoSE.

Extreme events are becoming more frequent due to anthropogenic climate change, posing serious concerns on societal and economic impacts and asking for mitigating strategies, as for Venice. Here we proposed a dynamical diagnostic of Extreme Sea Level (ESL) events in the Venice lagoon by using two indicators based on combining extreme value theory and dynamical systems: the instantaneous dimension and the inverse persistence. We show that the latter allows us to localize ESL events with respect to sea level fluctuations around the astronomical tide, while the former informs us on the role of active processes across the lagoon and specifically on the constructive interference of atmospheric contributions with the astronomical tide. We further examined the capability of the MoSE (Experimental Electromechanical Module), a safeguarding system recently put into operation, in mitigating extreme flooding events in relation with the values of the two dynamical indicators. We show that the MoSE acts on the inverse persistence in reducing/controlling the amplitude of sea level fluctuation and provide a valuable support for mitigating ESL events if operating, in a full operational mode, at least several hours before the occurrence an event.

Rapid System to Detect Variants of SARS-CoV-2 in Nasopharyngeal Swabs.

Currently, the reference method for identifying the presence of variants of SARS-CoV-2 is whole genome sequencing. Although it is less expensive than in the past, it is still time-consuming, and interpreting the results is difficult, requiring staff with specific skills who are not always available in diagnostic laboratories. The test presented in this study aimed to detect, using traditional real-time PCR, the presence of the main variants described for the spike protein of the SARS-CoV-2 genome. The primers and probes were designed to detect the main deletions that characterize the different variants. The amplification targets were deletions in the S gene: 25-27, 69-70, 241-243, and 157-158. In the ORF1a gene, the deletion 3675-3677 was chosen. Some of these mutations can be considered specific variants, while others can be identified by the simultaneous presence of one or more deletions. We avoided using point mutations in order to improve the speed of the test. Our test can help clinical and medical microbiologists quickly recognize the presence of variants in biological samples (particularly nasopharyngeal swabs). The test can also be used to identify variants of the virus that could potentially be more diffusive as well as not responsive to the vaccine.

Green Nail Syndrome Treated with Ozenoxacin: Two Case Reports.

Green nail syndrome (GNS) is a persistent greenish pigmentation of the nail plate, originally described in 1944 by Goldman and Fox, due to Pseudomonas aeruginosa infection. Recently, pulmonary co-infection of P. aeruginosa and Achromobacter spp. has been described in patients with cystic fibrosis. Achromobacter xylosoxidans is a multidrug-resistant (MDR) pathogen involved in lung and soft tissue skin infections. Both Achromobacter xylosoxidans and P. aeruginosa are mainly found in humid environments or in water. There are no recognized co-infections due to P. aeruginosa and A. xylosoxidans in the skin and appendages. We describe two cases of GNS, the first due to P. aeruginosa associated with Achromobacter xylosoxidans; the other due to MDR P. aeruginosa, both successfully treated with topical ozenoxacin 1% cream daily for 12 weeks. The clinical management of GNS can be confusing, especially when the bacterial culture result is inconsistent or when non-Pseudomonas bacteria are isolated. In our case, due to the co-infection of P. aeruginosa and Achromobacter spp., local treatment with ozenoxacin - the first nonfluorinated quinolone - could be a safe and effective treatment in case of MDR nail infections. Further studies are required to evaluate clinical isolation from nail infections and the co-presence of P. aeruginosa and A. xylosoxidans.

Closing the Gap in Proteomic Identification of Histoplasma capsulatum: A Case Report and Review of Literature.

Histoplasmosis is a globally distributed systemic infection caused by the dimorphic fungus Histoplasma capsulatum (H. capsulatum). This fungus can cause a wide spectrum of clinical manifestations, and the diagnosis of progressive disseminated histoplasmosis is often a challenge for clinicians. Although microscopy and culture remain the gold standard diagnostic tests for Histoplasma identification, matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) has emerged as a method of microbial identification suitable for the confirmation of dimorphic fungi. However, to our knowledge, there are no entries for H. capsulatum spectra in most commercial databases. In this review, we describe the case of disseminated histoplasmosis in a patient living with HIV admitted to our university hospital that we failed to identify by the MALDI-TOF method due to the limited reference spectrum of the instrument database. Furthermore, we highlight the utility of molecular approaches, such as conventional polymerase chain reaction (PCR) and DNA sequencing, as alternative confirmatory tests to MALDI-TOF technology for identifying H. capsulatum from positive cultures. An overview of current evidence and limitations of MALDI-TOF-based characterization of H. capsulatum is also presented.

Laboratory Automation in Microbiology: Impact on Turnaround Time of Microbiological Samples in COVID Time.

BACKGROUND: Laboratory Automation (LA) is an innovative technology that is currently available for microbiology laboratories. LA can be a game changer by revolutionizing laboratory workflows through efficiency improvement and is also effective in the organization and standardization of procedures, enabling staff requalification. It can provide an important return on investment (time spent redefining the workflow as well as direct costs of instrumentation) in the medium to long term. METHODS: Here, we present our experience with the WASPLab® system introduced in our lab during the COVID-19 pandemic. We evaluated the impact due to the system by comparing the TAT recorded on our samples before, during, and after LA introduction (from 2019 to 2021). We focused our attention on blood cultures (BCs) and biological fluid samples (BLs). RESULTS: TAT recorded over time showed a significant decrease: from 97 h to 53.5 h (Δ43.5 h) for BCs and from 73 h to 58 h (Δ20 h) for BLs. Despite the introduction of the WASPLab® system, we have not been able to reduce the number of technical personnel units dedicated to the microbiology lab, but WASPLab® has allowed us to direct some of the staff resources toward other laboratory activities, including those required by the pandemic. CONCLUSIONS: LA can significantly enhance laboratory performance and, due to the significant reduction in reporting time, can have an effective impact on clinical choices and therefore on patient outcomes. Therefore, the initial costs of LA adoption must be considered worthwhile.

Oxidation of Aqueous Phosphorous Acid Electrolyte in Contact with Pt Studied by X-ray Photoemission Spectroscopy.

The oxidation of the aqueous H3PO3 in contact with Pt was investigated for a fundamental understanding of the Pt/aqueous H3PO3 interaction with the goal of providing a comprehensive basis for the further optimization of high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs). Ion-exchange chromatography (IEC) experiments suggested that in ambient conditions, Pt catalyzes H3PO3 oxidation to H3PO4 with H2O. X-ray photoelectron spectroscopy (XPS) on different substrates, including Au and Pt, previously treated in H3PO3 solutions was conducted to determine the catalytic abilities of selected metals toward H3PO3 oxidation. In situ ambient pressure hard X-ray photoelectron spectroscopy (AP-HAXPES) combined with the "dip-and-pull" method was performed to investigate the state of H3PO3 at the Pt|H3PO3 interface and in the bulk solution. It was shown that whereas H3PO3 remains stable in the bulk solution, the catalyzed oxidation of H3PO3 by H2O to H3PO4 accompanied by H2 generation occurs in contact with the Pt surface. This catalytic process likely involves H3PO3 adsorption at the Pt surface in a highly reactive pyramidal tautomeric configuration.

All-Trans Retinoic Acid Effect on Candida albicans Growth and Biofilm Formation.

Candida albicans (C. albicans) is the most common fungal pathogen causing recurrent mucosal and life-threatening systemic infections. The ability to switch from yeast to hyphae and produce biofilm are the key virulence determinants of this fungus. In fact, Candida biofilms on medical devices represent the major risk factor for nosocomial bloodstream infections. Novel antifungal strategies are required given the severity of systemic candidiasis, especially in immunocompromised patients, and the lack of effective anti-biofilm treatments. Retinoids have gained attention recently due to their antifungal properties. MATERIAL AND METHODS: The present study aimed at evaluating the in vitro effects of different concentrations (300 to 18.75 µg/mL) of All-trans Retinoic Acid (ATRA), a vitamin A metabolite, on Candida growth and biofilm formation. RESULTS: ATRA completely inhibited the fungal growth, by acting as both fungicidal (at 300 µg/mL) and fungistatic (at 150 µg/mL) agent. Furthermore, ATRA was found to negatively affect Candida biofilm formation in terms of biomass, metabolic activity and morphology, in a dose-dependent manner, and intriguingly, its efficacy was as that of amphotericin B (AmB) (2-0.12 µg/mL). Additionally, transmission electron microscopy (TEM) analysis showed that at 300 µg/mL ATRA induced plasma membrane damage in Candida cells, confirming its direct toxic effect against the fungus. CONCLUSION: Altogether, the results suggest that ATRA has a potential for novel antifungal strategies aimed at preventing and controlling biofilm-associated Candida infections.