Physical genetics: Cross-breeding density functional theory and X-ray photoelectron spectroscopy to rationalize chemical shifts of binding energies in solid compounds

Like other spectroscopic methods XPS and AES show characteristic chemical shifts depending on the elemental matrix of a compound, however, a satisfactory rationalization of the variance of such values is often difficult. By an extension of a previous approach we present a theory in a unifying equation which combines several parameters - some of them resulting from DFT calculations - which influence the energy of the outgoing electrons and thereby seemingly the binding energy. By calculating Bader charges, atomic volumes and site potentials we have produced a data basis for a set of chalcogenides and halides of Ba, Zn, Pb and Cu to rationalize the spread of measured binding energies and Auger energies. It has thereby become possible to quantify different factors separately which bias the measurement of the kinetic energies of the outgoing core electrons, both the photo-emitted and the Auger electrons. Such an analysis can also trace special features of an open-shell configuration and even show up effects of a semiconductor-type

Relationship between the Auger parameter and the ground state valence charge at the core-ionized site

A simple semi-empirical model that correlates the Auger parameter to the ground state valence charge of the core-ionized atom with closed valence shell configuration, and which was previously applied to Cu(I) (3d10) compounds, is extended to Ba (II) (5d10), Pb (II) (5d104s2), and Zn (II) (3d10) compounds (halides and chalcogenides). Until now, the Auger parameter was employed to separate initial and final state effects that influence the core electron binding energy. In agreement with our model, a linear relationship is found between the Auger parameter shift and the ground state Bader valence charge obtained by density functional theory (DFT) calculations

Densità dell’ozono e dello zolfo allo stato di vapore nel Sunto di Cannizzaro

Riassunto Nella prima tabella riportata nel Sunto di Cannizzaro (Nuovo Cimento 7, 321-366 (1858), p.325) i valori delle densità di vapore relativi all’idrogeno (la mezza molecola d’idrogeno) per l’ossigeno elettrizzato (ozono) e lo solfo, sotto e sopra 1000°C, sono rispettivamente 128, 192 e 64. Le rispettive formule molecolari sarebbero quindi O8 per l’ozono, S6 per lo zolfo sotto 1000°C e S2 per lo zolfo sopra 1000°C. Riportiamo a scopo didattico-storico i nostri calcoli su queste semplici specie molecolari, effettuati a scopo ricreativo durante la clausura a cui ci ha costretto la supramolecola SARS-CoV-2.Abstract In the first table reported in the Cannizzaro’s Sunto (Nuovo Cimento 7, 321-366 (1858), p.325) the relative vapor density with respect to hydrogen (half the hydrogen molecule) for electrified oxygen (ozone) and sulphur, below and above 1000°C, are 128, 192 e 64, respectively. The molecular formulas would be O8 for ozone, and S6 and S2 for sulphur below and above 1000°C, respectively. In this note we report our calculations on these simple molecular species, done with historical and didactical purposes, and recreational scope during the closure imposed to all of us by the supramolecule SARS-CoV-2

Avogadro, Cannizzaro e la "legge degli atomi"

In this contribution Avogadro’s hypothesis and the law of atoms proposed by Cannizzaro are presented as a new teaching approach to help our students to gain a better understanding of the laws of classical chemistry. We avoid the very common error to attribute to Avogadro the writing of the correct formula of water, and also suggest a possible explanation of Cannizzaro’s hypothesis regarding the diatomic formula of molecular hydrogen

L'elettrolisi: un'occasione per riflettere sulla Chimica, ma anche sulla storia, l'economia, l'ambiente

Pensiamo che partire da esempi tratti dal mondo che ci circonda, in cui le procedure della Chimica, sia teoriche che sperimentali, appaiano in tutto il loro intreccio con le attività umane, possa costituire un metodo efficace per fornire a vari livelli un’immagine della disciplina corretta. Ciò può aiutare ad approcciarsi ad essa senza paure e senza trionfalismi. Nell’articolo in particolare si tratteranno alcuni significativi processi di elettrolisi, evidenziando il loro sviluppo storico e le loro implicazioni dal punto di vista produttivo e del rapporto con uomo e ambiente.We believe that an effective way to provide, at various levels, a correct image of Chemistry could be based on examples from the world around us, in which the procedures of the discipline, both theoretical and experimental, appear in all their interweaving with human activities. This may help to approach it without fear and without triumphalism. In the article in particular we discuss some significant electrolysis processes, highlighting their his- torical development and their implications from the point of view of production and the rela- tionship with man and environment

Dalle formule di struttura di Lewis ai concetti di numero di ossidazione, carica formale e carica effettiva di un atomo in una molecola

Riassunto I concetti di elettronegatività assoluta e di durezza assoluta degli atomi liberi, nel loro stato elettronico fondamentale, e il principio di equalizzazione dell’elettronegatività degli atomi nelle molecole, sono qui utilizzati insieme alle formule di struttura di Lewis e al modello di Gillespie (VSEPR) per determinare la probabile geometria molecolare, per una didattica della Chimica generale coerente ed efficace che a partire da una semplice formula analitica, permette di introdurre i concetti di numero di ossidazione, di carica formale e di carica effettiva per ogni atomo in una molecola.Abstract The concepts of absolute electronegativity and absolute hardness of the free atoms, in their electronic ground state, and the principle of the electronegativity equalization for the atoms in molecules, are used together with the Lewis structures and the Gillespie model (VSEPR) for the definition of the molecular geometry, to present in the General chemistry course the concepts of oxidation number, of formal charge and effective charge for the atom in a molecule by means of a simple analytical formula

La diagnostica per la conoscenza storica e artistica delle opere d'arte. Il ruolo delle analisi sui pigmenti nel restauro degli affreschi di Michelangelo nella Cappella Sistina

Il pensiero inerente la tutela delle opere d’arte ha subito una notevole evo- luzione nel corso della storia ed oggi è diventato indispensabile affiancare la scienza della conservazione alle consuete metodologie di restauro. Le scienze applicate ai Beni Culturali coinvolgono studiosi provenienti da diversi campi di ricerca e la collaborazione diventa una prerogativa imprescindibile per il successo dell’intervento conservativo e, soprattutto, per la conoscenza approfondita dell’opera in tutti i suoi aspetti, dai materiali costitutivi alla tecnica di realizzazione. Nell’articolo illustreremo quanto detto soffermandoci tra l’altro sul restauro degli affre- schi di Michelangelo della Cappella Sistina. Questo è stato definito come il primo restauro moderno, proprio perché le analisi hanno accompagnato ogni intervento tecnico sugli affre- schi, i quali sono tornati allo splendore originario nel rispetto dei principi teorici del restauro. In questo e in altri casi la diagnostica è diventata quindi un importante ausilio per lo stu- dio dei Beni Culturali, anche se la scelta della tecnica analitica deve essere relazionata sempre alla domanda alla quale si cerca la risposta. Le scienze applicate permettono di approfondire la storia dell’opera, la tecnica dell’artista, caratterizzano i materiali, ricostruendone le antiche rotte commerciali; tutte queste informazioni permettono di raggiungere una conoscenza senza pari, indispensabile per la valorizzazione, la tutela e la conservazione dei Beni Culturali.he approach to the protection of artwork has considerably evolved through- out history; placing side by side the conservation science and the usual methods of restoration has today become unavoidable. Science Applied to Cultural Heritage involves scholars from different research fields making their collaboration of paramount importance for the success of the conservation process and, above all, for the in-depth knowledge of the artwork in all its aspects, from the constituent materials to the realization technique. This article will discuss this topic taking into particular account the restoration of Michelangelo’s frescoes in the Sistine Chapel. This was defined as the first modern restoration, because scientific tests have accompanied for the first time any technical intervention on the frescoes, which were returned to their original splendor in respect of the theoretical principles of restoration. In this specific case and in other ones, the diagnostics has therefore become an important aid in Cultural Heritage studies, provided that the choice of the analytical technique is always related to the answer that one is trying to pursue. Applied sciences provide an insight into the history of the artworks, the artists’ techniques, the knowledge of employed materials – that allow one to reconstruct the ancient trade routes; all this information can accomplish an unsurpassed knowledge, which is becoming essential for the development, protection and conservation of Cultural Heritage

Behavioral and Neurophysiological Effects of Transdermal Rotigotine in Atypical Parkinsonism

Effective therapies for the so-called atypical parkinsonian syndrome (APS) such as multiple system atrophy (MSA), progressive supranuclear palsy (PSP), or corticobasal syndrome (CBS) are not available. Dopamine agonists (DA) are not often used in APS because of inefficacy and in a minority of case, their side effects, like dyskinesias, impairment of extrapyramidal symptoms or the appearance of psychosis, and REM sleep behavioral disorders (RBD). Transdermal rotigotine (RTG) is a non-ergot dopamine agonist indicated for use in early and advanced Parkinson’s disease with a good tolerability and safety. Moreover, its action on a wide range of dopamine receptors, D1, D2, D3, unlike other DA, could make it a good option in APS, where a massive dopamine cell loss is documented. In this pilot, observational open-label study we evaluate the efficacy and tolerability of RTG in patients affected by APS. Thirty-two subjects with diagnosis of APS were treated with transdermal RTG. APS diagnosis was: MSA parkinsonian type (MSA-P), MSA cerebellar type (MSA-C), PSP, and CBS. Patients were evaluated by UPDRS-III, neuropsychiatric inventory, mini mental state examination at baseline, and after 6, 12, and 18 months. The titration schedule was maintained very flexible, searching the major clinical effect and the minor possible adverse events (AEs) at each visit. AEs were recorded. APS patients treated with RTG show an overall decrease of UPDRS-III scores without increasing behavioral disturbances. Only three patients were dropped out of the study. Main AEs were hypotension, nausea, vomiting, drowsiness, and tachycardia. The electroencephalographic recording power spectra analysis shows a decrease of theta and an increase of low alpha power. In conclusion, transdermal RTG seems to be effective and well tolerated in APS patients

Comparison of the effects of transdermal and oral rivastigmine on cognitive function and EEG markers in patients with Alzheimer’s disease

Background: Alzheimer's disease (AD) is the most common cause of dementia in older patients. Rivastigmine (RV, Exelon®, Novartis), a reversible cholinesterase inhibitor, improves clinical manifestations of AD and may enhance ACh-modulated electroencephalogram (EEG) alpha frequency. This pilot study aimed to determine the effects of two formulations of RV (transdermal patch [TV-RDP] and oral capsules [TV-CP]) on alpha frequency, in particular the posterior dominant rhythm, and cognitive function (assessed by the Mini-Mental State Examination [MMSE]) in patients with AD.Methods: Subjects with AD were assigned to receive either RV-TDP 10 cm2 or RV-CP 12 mg/day. All patients underwent EEG recordings at the beginning and end of the 18-month study period using P3, P4, O1 and O2 electrodes, each at high (10.5–13.0 Hz) and low (8.0–10.5 Hz) frequency. MMSE scores were determined at the start of the study (T0) and at three successive 6-month intervals (T1, T2 and T3).Results: RV-TDP administration (n=10) maintained cognitive function as evidenced by stable MMSE scores from baseline to 18 months (21.07 ± 2.4 to 21.2 ± 3.1) compared with a decrease in MMSE score with RV-CP (n=10) over 18 months (18.3 ± 3.6 to 13.6 ± 5.06 [adjusted for covariates p=0.006]). MMSE scores were significantly different between treatment groups from 6 months (p=0.04). RV-TDP also increased the spectral power of alpha waves in the posterior region measured with electrode P3 in a significantly great percentage of patients than TV-CP from baseline to 18 months; 80% versus 30%, respectively (p=0.025 [χ2 test]).Conclusion: RV-TDP was associated with a greater proportion of patients with increased posterior region alpha wave spectral power and significantly higher cognitive function at 18 months, compared with RV-CP treatment. Our findings suggest that RV-TDP provides an effective long-term management option in patients with AD compared with oral RV-CP. This study is a pilot, open-label study with

Anatomical Substrate and Scalp EEG Markers are Correlated in Subjects with Cognitive Impairment and Alzheimer's Disease

Dementia is a syndromic diagnosis, encompassing various stage of severity and different anatomo-physiological substrates. The hippocampus is one of the first and most affected brain regions affected by both Alzheimer's disease (AD) and mild cognitive impairment (MCI). Moreover, chronic cerebrovascular disease (CVD) is one of the major risk factor for developing dementia. Recent studies have demonstrated different relationship between the anatomical substrate and scalp electroencephalography (EEG) markers. Indeed, modifications of EEG rhythmicity is not proportional to the hippocampal atrophy, whereas changes in EEG activity are directly proportional to the load of subcortical CVD. The computation of the EEG spectral power and the analysis of the functional coupling of brain areas, through linear coherence, are two of the most known processing methods in EEG research. Two specific EEG markers, theta/gamma and alpha3/alpha2 frequency ratio have been reliable associated to the atrophy of amygdalo–hippocampal complex. Moreover, theta/gamma ratio has been related to MCI conversion in dementia and alpha3/alpha2 ratio has been specifically related to MCI conversion in AD. The functional coupling of brain areas is also modulated by hippocampal atrophy. In the MCI subjects, hippocampal atrophy is linked to an increase of interhemispheric coherence seen on frontal and temporal regions whereas subcortical CVD is linked to a decrease of coherence in fronto-parietal regions. In the present study the most significant results of recent studies on correlation between scalp EEG, cognitive decline, and anatomical substrate have been reviewed, with particular attention to the relationships between EEG changes and hippocampal atrophy. The following review is not intended to provide a comprehensive summary of the literature. Rather it identifies and discusses selected studies that are designed to find the specific correlation between scalp EEG markers and anatomo-pathological substrate. The principal aim is to propose a plausible neurophysiological theoretical model of the cognitive decline as mirrored by both structural and functional tools of research