Photoelectrochemical behavior of electrophoretically deposited hematite thin films modified with ti(IV)

: Doping hematite with different elements is a common strategy to improve the electrocatalytic activity towards the water oxidation reaction, although the exact effect of these external agents is not yet clearly understood. Using a feasible electrophoretic procedure, we prepared modified hematite films by introducing in the deposition solution Ti(IV) butoxide. Photoelectrochemical performances of all the modified electrodes were superior to the unmodified one, with a 4-fold increase in the photocurrent at 0.65 V vs. SCE in 0.1 M NaOH (pH 13.3) for the 5% Ti-modified electrode, which was the best performing electrode. Subsequent functionalization with an iron-based catalyst led, at the same potential, to a photocurrent of ca. 1.5 mA?cm-2 , one of the highest achieved with materials based on solution processing in the absence of precious elements. AFM, XPS, TEM and XANES analyses revealed the formation of different Ti(IV) oxide phases on the hematite surface, that can reduce surface state recombination and enhance hole injection through local surface field effects, as confirmed by electrochemical impedance analysis

Potentialities of the Imaging Spectroscopy to deal with the Prevention in the Cultural Heritage Field

La prevenzione, nella conservazione dei beni culturali, raggruppa tutta una serie di procedure che spaziano dalla riduzione dei fattori di rischio alle adeguate modalità di diagnostica. Queste azioni possono essere eseguite a diversi livelli e in tempistiche differenti ma passano per una conoscenza accurata del bene sia dal punto di vista dei materiali costitutivi che dei diversi interventi e delle condizioni di conservazione dell’opera lungo tutto l’arco della sua esistenza. In questo senso le tecniche diagnostiche non distruttive sono uno strumento particolarmente utile per una corretta progettazione dell’azione preventiva. Queste tecniche permettono infatti di individuare i materiali costitutivi, in modo da valutare le condizione ottimali di conservazione o, nel caso occorresse un intervento, di proporre i materiali adeguati per questa operazione. Questa applicazione delle tecniche d’indagine non distruttive è quella più nota quando si affronta la problematica della prevenzione, ma non l’unica. Alcune di queste tecniche permettono anche di monitorare nel tempo l’evoluzione del bene culturale, in modo da rilevare i cambiamenti che possono essere dovuti ad eventuali patologie che, se rilevate per tempo, possono essere risanate prevenendo i possibili effetti dovuti alle alterazioni e al degrado. Se a queste potenzialità si aggiunge la possibilità di “mappare” sia i materiali costitutivi che le diverse alterazioni dell’intera superficie dell’opera, ci troviamo davanti a degli strumenti estremamente validi nell’ambito della prevenzione. E’ dunque compito degli esperti degli ambiti disciplinari coinvolti (soprintendenze, restauratori, scienziati…), arrivare alla massima fruizione di questi strumenti. A tale scopo è indispensabile un dialogo attivo su cosa si vuole e su cosa è possibile ottenere. Il lavoro che si intende proporre presenta una serie di indagini eseguite con la tecnica della spettroscopia ad immagine (IS), realizzate in stretta collaborazione tra il Dipartimento di Scienze Chimiche, il Dipartimento di Ingegneria dell’Informazione dell’Università di Padova e il Laboratorio LUXOR dell’Istituto di Fotonica e Nanotecnologie. Si intende mostrare la capacità di tale tecnica per identificare, monitorare e mappare materiali riguardanti i beni culturali, come ad esempio i pigmenti. Grazie alle informazioni ottenute con la metodologia di analisi proposta è possibile caratterizzare questi materiali e monitorarli nel tempo rilevando cambiamenti di colore impercettibili ad occhio nudo. Lo strumento utilizzato registra gli spettri in riflettanza diffusa nel visibile dei singoli pixel dell’immagine digitale fornendo quindi informazioni sul colore e permettendo di caratterizzare i pigmenti presenti. Oltre a ciò, attraverso le elaborazioni dei dati è possibile ricostruire l’immagine RGB del campione sotto analisi riproducendo il colore dei singoli pixel in maniera asettica e fedele. Il sistema proposto ha il vantaggio di essere trasportabile e di realizzare mappature non distruttive in modo da studiare l’intera superficie dell’oggetto sotto analisi in situ. Infine si proporrà un sistema di gestione dei dati che può essere il punto di partenza per la progettazione della prevenzione. Il metodo di lavoro sarà illustrato mediante prove realizzate in laboratorio e indagini realizzate su un dipinto murale presso la biblioteca della Facoltà di Scienze Statistiche dell’Università di Padova

Non-invasive multitechnique methodology applied to the study of two XIV-Century Canvases by Lorenzo Veneziano

This paper presents the results of a multi-disciplinary study on two XIV century canvases attributed to Lorenzo Veneziano. In particular, two non-invasive spectroscopic techniques have been employed, imaging spectroscopy (IS) and X-ray Fluorescence (XRF). In order to perform the analysis in situ, the employed instruments were transportable. The purposes of this analytical approach were mainly to corroborate the authorship and to study the painting materials and execution technique of these two paintings. These two artworks are considered precious because they represent two evidences of the early use of the canvas support in this early period in the North of Italy. The paintings are in very delicate conditions. For this reason, the principal objective of the investigations was to gather as much information as possible avoiding invasive analytical procedures. The paper discusses the potentialities and limitations of the integration of a mobile XRF with a transportable IS device, specially developed to study large-sized surfaces. By means of the elemental composition given by XRF and the colourimetric data and reflectance spectra collected by IS, it has been possible to identify different painting materials (gypsum, azurite\u2026) and to obtain a better understanding of the employed execution practise. The data confirm that the two canvases have been produced with painting materials and technique that are in good correspondence between them and that corroborate the authorship to Lorenzo Veneziano. The obtained results illustrate the suitability of the integration of XRF with IS to solve similar analytical issues when sampling is not possible

The spread of SARS-CoV-2 at school through the different pandemic waves: a population-based study in Italy

Proactive school closures are often considered an effective strategy by policy-makers and the public to limit SARS-CoV-2 transmission. While evidence on the role of students in the spread is debated, the effects of closures on children's well-being are well known. In the light of this, we aimed to assess viral spread in educational settings, by calculating the rate of secondary infections per school class and identifying factors associated with cluster generation. We conducted a combined longitudinal and cross-sectional population-based study between October 2020 and November 2021. Secondary screening was conducted whenever a SARS-CoV-2 positive subject had been in the school environment in 48 h prior to symptoms onset or on the date of swab, if asymptomatic. The effect of selected variables on COVID-19 cluster generation was assessed by logistic regression. We identified 1623 primary COVID-19 cases. Of these, 72.5% resulted in no secondary case, 15.6% in 1, and 11.9% in 2 + . The probability of generating a 2 + cluster was lower when the index case was a student, rather than school staff (AOR = 0.42; 95%CI: 0.29-0.60). The number of clusters per week was in line with COVID-19 incidence trend in the general population

Immunohistochemical detection of P-Glycoprotein (Clone C494) in canine mammary gland tumours. Journal of Veterinary Medicine, Series A, 53, 174 \u2013 178.

Elevated levels of P-glycoprotein have been reported in multidrug-resistant tumours in both humans and dogs. In the present study, we investigated the expression of P-glycoprotein in 57 canine mammary gland tumours, 10 mammary gland hyperplasia and seven normal mammary glands by immunohistochemistry. Tissue sections were incubated with an anti-Pgp monoclonal antibody and visualized with En Vision-DAB polymer. Normal and hyperplastic mammary tissues were negative or showed slight cytoplasmic immunoreactivity. Neoplastic cells in benign mammary tumours showed diffuse cytoplasmic staining, in contrast to malignant tumours that showed mainly a membranous staining pattern for Pgp (C494). We observed statistically significant differences among all the different groups of tissues analysed except for benign tumours versus hyperplasia (P = 0.221). Receiver-operating characteristic analysis showed that the best cut-off point to differentiate the threshold to differentiate negative from positive tissue samples was 18.40% of immunostained cells. These results provide a first indication that routine evaluation of Pgp expression in canine mammary gland tumours, taking into consideration a cut-off point for positivity, may be useful for selecting cases for chemotherapy

CdTe solar cells: technology, operation and reliability

Over the last 20 years, the technological improvements of CdTe solar cell have been impressive, and today the performance of these cells is comparable with that of silicon cells. Behind these important results, there have been important research efforts, aimed at exploring every single aspect related to CdTe cell optimization. One of these is reliability, that is fundamental in the perspective of massive commercialization. The aim of this review paper is to explore the main aspects related to the operation and reliability of CdTe solar cells, and describe the most relevant results presented in the literature on these topics. The paper is divided in two parts. The first is dedicated to a general introduction of CdTe issues. In this part, we report the most relevant details on CdTe solar cells from a reliability perspective, including (a) a description of the CdTe solar cells development on the years, (b) a description of the main production methods, (c) an overview of the main mathematical model to describe a solar cell, and (d) the main normative requirements related to solar cell reliability. The second section describes the most important papers in the field of CdTe solar cell reliability, along with two recent case studies, that can be used as an example to understand the complexity of the involved processes. The results are critically discussed by considering the most recent literature on the topic, to provide a general overview to the reader willing to approach the topic

Ampulla of Vater Carcinoma: Sequencing Analysis Identifies TP53 Status as a Novel Independent Prognostic Factor and Potentially Actionable ERBB, PI3K, and WNT Pathways Gene Mutations

Objective: To identify molecular prognostic factors and potentially actionable mutations in ampulla of Vater cancer (AVC). Background: The largely variable outcomes of AVCs make clinical decisions difficult regarding the need of postsurgical therapy, which is based on morphological and immunohistochemical classification that do not adequately consider the varying degrees of heterogeneity present in many AVCs. No approved targeted therapies for AVC exist, but some show promising results requiring better molecular characterization to identify potential responders. Methods: We assessed 80 AVCs for the prognostic value of mutations of kirsten rat sarcoma (KRAS), neuroblastoma RAS (NRAS), B rapidly accelerated fibrosarcoma (BRAF), TP53, and 4 membrane erythroblastosis oncogene B (ERBB) receptor tyrosine kinases (EGFR-ERBB1, HER2-ERBB2, HER3-ERBB3, HER4-ERBB4) amenable to pharmacological inhibition. Moreover, we evaluated mutations in 16 key components of rat sarcoma (RAS), phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K), protein 53 (P53), transforming growth factor beta (TGF-\u3b2), and wingless/integrated (WNT) pathways, recently associated to AVC by whole-exome sequencing. Results: TP53 and KRAS were mutated in 41% and 35% of cases, respectively, and emerged as independent prognostic factors together with tumor stage and regardless of the histotype (TP53: P = 0.0006; KRAS: P = 0.0018; stage IIB: P = 0.0117; stage III-IV: P = 0.0020). ERBB, WNT and PI3K pathway genes were mutated in 37.5% of cases. Conclusions: KRAS and TP53 mutations are negative predictors of survival in AVCs, regardless of histotype. Potentially actionable mutations in ERBB, WNT, and PI3K signaling pathway genes are present in 37.5% of all cases. These might be amenable to target therapy using available drugs like Everolimus in PI3K-mutated cases or compounds under active screening against ERBB and WNT signaling