Interactions métal/ligand à la surface d’oxydes métalliques et de nanostructures

La présente thèse étudie les oxydes métalliques et leur engagement dans les différents domaines. Nous avons concentré nos travaux sur les domaines de la géochimie environnementale, du patrimoine culturel et de la photocatalyse basée sur les interactions des oxydes métalliques. Géochimie environnementale. Les ZnO sont des systèmes courants présents dans divers contextes et également des systèmes modèles largement étudiés. Les nanoparticules de ZnO se trouvent dans le sol et l'eau, il est donc important d'étudier le devenir et le comportement de ce matériau dans l'environnement, et les isotopes sont des outils efficaces pour atteindre cet objectif. Des simulations informatiques peuvent compléter l'analyse directe des matériaux de ces systèmes. En particulier, nous avons concentré notre étude théorique sur l'évaluation de l'effet de surface sur la signature isotopique. Les nanoparticules de ZnO ont-elles une composition isotopique de Zn différente de celle des cristaux de ZnO en vrac dans des conditions d'équilibre ? Afin de répondre à cette question, nous avons effectué des calculs de structure et de fréquence basés sur la DFT sur différents modèles structurels. Les propriétés isotopiques sont ensuite déterminées à partir des fréquences vibrationnelles. Trois types de modèles structuraux ont été considérés : la structure brute du ZnO, les surfaces des dalles (1 0 1 ¯ 0) et (2 1 ¯ 1 ¯ 0), et une nanoparticule modèle. Les résultats obtenus permettent de discuter de l'effet de surface et des propriétés isotopiques des nanoparticules de ZnO. Héritage culturel. Des stratégies avancées de modélisation informatique ont été appliquées au patrimoine culturel pour comprendre les processus de dégradation des matériaux de peinture. La dégradation du ZnO conduit à la formation de complexes d'ions Zn et d'acides gras. S'agissant d'un problème sérieux affectant l'apparence des peintures à l'huile, il est pertinent de caractériser la structure de ces complexes pour comprendre les voies réactionnelles de ce processus de dégradation. Des calculs DFT ont été effectués pour étudier l'adsorption d'acétate et d'acide acétique sur des amas de ZnO et la formation de complexes Zn-acétate. Les acides carboxyliques avec des chaînes alkyles plus longues ont ensuite été étudiés comme modèles plus réalistes d'acides gras. Des calculs DFT utilisant une dalle périodique de ZnO ont été effectués pour comparer les résultats obtenus à différents niveaux de théorie. Les calculs d'optimisation et les énergies de formation des systèmes couplés ZnO@carboxylate et la thermodynamique conduisant à d'éventuels produits de dégradation ont été calculés. Nos résultats mettent en évidence le potentiel des calculs DFT pour mieux comprendre la dégradation des peintures dans le but de renforcer les stratégies des peintures. En photocatalyse, des réactions peuvent avoir lieu en utilisant la lumière et un semi-conducteur : dans ce mécanisme, une paire électron-trou est générée lors de l'exposition d'un matériau semi-conducteur à la lumière, puis l'électron excité est utilisé pour réduire une espèce acceptrice tandis que le trou peut simultanément s'oxyder une espèce donneuse. Les propriétés photocatalytiques du TiO2 en font un photocatalyseur idéal. Il affiche une énergie de bande interdite élevée et est connu pour rendre le processus de dégradation photocatalytique peu coûteux et facile sous la lumière du soleil. Le ZnO a également montré un immense potentiel en tant que photocatalyseurs et présente des propriétés similaires à celles du TiO2. Ce travail donne un aperçu des effets de la photocatalyse pour dégrader le coronavirus à l'aide de semi-conducteurs d'oxyde métallique TiO2 et ZnO. Dans cette étude préliminaire, nous nous sommes concentrés sur l'interaction entre TiO2 / ZnO et des modèles de phospholipides qui assemblent l'environnement du coronavirus et pourraient s'adsorber à la surface, en utilisant différents modèles et méthodes pour calculer l'énergie associée à l'adsorption du phospholipide au niveau de l'oxyde métallique surface.The present thesis studies metal oxides and their engagement in the different domains. We focused our work on environmental geochemistry, cultural heritage, and photocatalysis fields based on metal oxides interactions. Environmental geochemistry. ZnO are common systems present in various contexts and also model systems widely studied. ZnO nanoparticles are found in soil and water, it is therefore important to study the fate and behavior of this material in the environment, and isotopes are efficient tools for achieving this goal. Computer simulations can complement the direct materials analysis of these systems. In particular, we focused our theoretical study on the assessment of the surface effect on the isotopic signature. Do ZnO nanoparticles have different Zn isotope composition from bulk ZnO crystals in equilibrium conditions? In order to address this question, we performed structure and frequency calculations based on DFT on various structural models. Isotopic properties are then determined from the vibrational frequencies. Three kinds of structural models were considered: ZnO bulk structure, the slab surfaces (1 0 1 ¯ 0) and (2 1 ¯ 1 ¯ 0), and a model nanoparticle. The results obtained allow us to discuss the surface effect and the isotopic properties of ZnO nanoparticles. Cultural heritage. Advanced computational modelling strategies have been applied to cultural heritage to understand the degradation processes of painting materials. The degradation of ZnO leads to the formation of complexes of Zn ions and fatty acids. Being a serious problem affecting the appearance of oil paintings, it is relevant to characterize the structure of these complexes to understand the reaction pathways of this degradation process. DFT calculations have been performed to investigate the adsorption of acetate and acetic acid on ZnO clusters and the formation of Zn-acetate complexes. Carboxylic acids with longer alkyl chains have then been investigated as more realistic models of fatty acids. DFT calculations using a periodic ZnO slab have been performed to compare the obtained results at different levels of theory. Optimization calculations and formation energies of ZnO@carboxylate coupled systems and the thermodynamics leading to possible degradation products have been computed. Our results highlight the potential of DFT calculations for better understanding paint degradation with the aim of strengthening strategies of paintings. In photocatalysis, reactions can take place using light and a semiconductor: in this mechanism, an electron-hole pair is generated upon exposure of a semiconductor material to light, then the excited electron is used to reduce an acceptor species while the hole can simultaneously oxidize a donor species. The photocatalytic properties of TiO2 make it an ideal photocatalyst. It displays high bandgap energy and is known to make photocatalytic degradation process inexpensive and easy under sunlight. ZnO has also shown immense potential as photocatalysts and exhibits similar properties to TiO2. This work provides insight into the effects of photocatalysis to degrade coronavirus using TiO2 and ZnO metal oxide semiconductors. In this preliminary study, we focused on the interaction between TiO2 / ZnO and phospholipid models which assemble the environment of the coronavirus and could adsorb on the surface, employing different models and methods to calculate the energy associated to the adsorption of phospholipid at the metal oxide surface

Mental Health Support in the Time of Crisis: Are We Prepared? Experiences With the COVID-19 Counselling Programme in Hungary

The Coronavirus disease 2019 (COVID-19) posed unexpected global economic and societal challenges. These include a heavy impact on mental health due to fast changing lockdown and quarantine measures, uncertainty about health and safety and the prospect of new waves of infections. To provide crisis mental health support during the pandemic, Eötvös Loránd University in Hungary launched a specialist online counselling programme, consisting of one to three sessions. The programme was available to all university members between 4th March and 25th May 2020. Overall, 47 clients received support. In this paper we discuss challenges reported by clients, key features of providing a brief mental health intervention online, reflect on counsellor experiences and give recommendations on how mental health services could be developed in the time of crisis. Most clients had challenges with developing a daily routine under quarantine; and many had hardship related to finances, housing, and distance learning. Common mental health consequences included fear from the virus and stress, anxiety, and fatigue due to the interruption to everyday life. In some cases, more complex conditions were triggered by the pandemic. Examples include addictive behaviours and symptoms of depression or psychosis. However, referring cases beyond the competency of counselling proved to be a challenge due to the closure of specialist services. Counsellors observed three key features to the online delivery of a brief crisis mental health intervention: [1] an explicit problem-oriented approach to counselling; [2] challenges of building rapport online; and [3] frames of online counselling. Counsellor experiences often overlapped with those of clients and included challenges of working from home and adjusting to online counselling methods. The possibility of online counselling allowed that mental health care could take place at all during the pandemic. Client experiences reflect findings from previous literature. Like other mental health initiatives launched to tackle COVID-19, the intervention's effectiveness was not measured given the unexpected context and short time frame for programme development. We recommend the use of impact measurement tools to develop mental health services in crises. Meanwhile, the pandemic brought to attention the need to better understand online delivery models. Counsellors should have access to training opportunities on online counselling and managing work-life balance in a remote setting. The COVID-19 counselling programme in Eötvös Loránd University, Hungary is an example of providing online mental health counselling in the time of crisis. Clearly, more studies are needed discussing delivery models and effectiveness of mental health interventions during the pandemic. Experience and knowledge sharing across practitioners should be encouraged to improve how the field reacts to unexpected, high risk events and crises

Problem Solving and Enhancing the Overall Equipment Effectiveness in Pharmaceutical Industries

Overall Equipment Effectiveness (OEE) is a method tomonitor and improve the efficiency of manufacturing processes.OEE is broken down into three measuring metrics; availability,performance, and quality. The aim of this research is to usethese metrics to benchmark the efficiency and effectiveness, andcategorize the key productivity losses that occur within apharmaceutical production plant. During the research, OEE ismeasured by using different devices and monitored in packagingdepartment of the plant. After that, data were analysed topropose different correction and improvement actions. Resultshave shown many problems that cause deterioration in OEE,such as using improper production parameters. By adoptingsome corrective actions, an OEE enhancement has been obtainedand losses have been reduced

Requirements Analysis for an Open Research Knowledge Graph

Current science communication has a number of drawbacks and bottlenecks which have been subject of discussion lately: Among others, the rising number of published articles makes it nearly impossible to get an overview of the state of the art in a certain field, or reproducibility is hampered by fixed-length, document-based publications which normally cannot cover all details of a research work. Recently, several initiatives have proposed knowledge graphs (KGs) for organising scientific information as a solution to many of the current issues. The focus of these proposals is, however, usually restricted to very specific use cases. In this paper, we aim to transcend this limited perspective by presenting a comprehensive analysis of requirements for an Open Research Knowledge Graph (ORKG) by (a) collecting daily core tasks of a scientist, (b) establishing their consequential requirements for a KG-based system, (c) identifying overlaps and specificities, and their coverage in current solutions. As a result, we map necessary and desirable requirements for successful KG-based science communication, derive implications and outline possible solutions.Comment: Accepted for publishing in 24th International Conference on Theory and Practice of Digital Libraries, TPDL 202

Unusual cardiovascular complications of brucellosis presenting in two men: two case reports and a review of the literature

Introduction: Brucellosis is a zoonosis with worldwide distribution, which is particularly endemic in many countries of the Mediterranean basin. Cardiovascular complications of this disease, such as endocarditis, myocarditis and pericarditis, are very rare, with even fewer cases of myocarditis or asymptomatic pericardial effusion in the absence of concomitant endocarditis being reported. Case presentation: We report two cases of brucellosis in two Caucasian men, aged 17 and 34 years old, with myocarditis and asymptomatic pericardial effusion, respectively. Of note, neither patient had concomitant endocarditis. The disease was confirmed serologically and by blood cultures. Both patients recovered completely after receiving appropriate antibiotic treatment without any sign of relapse during a follow-up of 12 months. Conclusion: These two cases emphasize that in endemic areas Brucella can be considered as a potentially causative agent of idiopathic pericardial effusion or myocarditis, even in the absence of concomitant endocarditis. This possibility could be taken into account particularly in cases where contraction of brucellosis is possible, such as occupational exposure or consumption of unpasteurized dairy products. © 2011 Gatselis et al; licensee BioMed Central Ltd

Systematic Review and Meta-Analysis of Randomized Clinical Trials in the Treatment of Human Brucellosis

BACKGROUND: Brucellosis is a persistent health problem in many developing countries throughout the world, and the search for simple and effective treatment continues to be of great importance. METHODS AND FINDINGS: A search was conducted in MEDLINE and in the Cochrane Central Register of Controlled Trials (CENTRAL). Clinical trials published from 1985 to present that assess different antimicrobial regimens in cases of documented acute uncomplicated human brucellosis were included. The primary outcomes were relapse, therapeutic failure, combined variable of relapse and therapeutic failure, and adverse effect rates. A meta-analysis with a fixed effect model was performed and odds ratio with 95% confidence intervals were calculated. A random effect model was used when significant heterogeneity between studies was verified. Comparison of combined doxycycline and rifampicin with a combination of doxycycline and streptomycin favors the latter regimen (OR = 3.17; CI95% = 2.05-4.91). There were no significant differences between combined doxycycline-streptomycin and combined doxycycline-gentamicin (OR = 1.89; CI95% = 0.81-4.39). Treatment with rifampicin and quinolones was similar to combined doxycycline-rifampicin (OR = 1.23; CI95% = 0.63-2.40). Only one study assessed triple therapy with aminoglycoside-doxycycline-rifampicin and only included patients with uncomplicated brucellosis. Thus this approach cannot be considered the therapy of choice until further studies have been performed. Combined doxycycline/co-trimoxazole or doxycycline monotherapy could represent a cost-effective alternative in certain patient groups, and further studies are needed in the future. CONCLUSIONS: Although the preferred treatment in uncomplicated human brucellosis is doxycycline-aminoglycoside combination, other treatments based on oral regimens or monotherapy should not be rejected until they are better studied. Triple therapy should not be considered the current treatment of choice

Interactions métal/ligand à la surface d’oxydes métalliques et de nanostructures

The present thesis studies metal oxides and their engagement in the different domains. We focused our work on environmental geochemistry, cultural heritage, and photocatalysis fields based on metal oxides interactions. Environmental geochemistry. ZnO are common systems present in various contexts and also model systems widely studied. ZnO nanoparticles are found in soil and water, it is therefore important to study the fate and behavior of this material in the environment, and isotopes are efficient tools for achieving this goal. Computer simulations can complement the direct materials analysis of these systems. In particular, we focused our theoretical study on the assessment of the surface effect on the isotopic signature. Do ZnO nanoparticles have different Zn isotope composition from bulk ZnO crystals in equilibrium conditions? In order to address this question, we performed structure and frequency calculations based on DFT on various structural models. Isotopic properties are then determined from the vibrational frequencies. Three kinds of structural models were considered: ZnO bulk structure, the slab surfaces (1 0 1 ¯ 0) and (2 1 ¯ 1 ¯ 0), and a model nanoparticle. The results obtained allow us to discuss the surface effect and the isotopic properties of ZnO nanoparticles. Cultural heritage. Advanced computational modelling strategies have been applied to cultural heritage to understand the degradation processes of painting materials. The degradation of ZnO leads to the formation of complexes of Zn ions and fatty acids. Being a serious problem affecting the appearance of oil paintings, it is relevant to characterize the structure of these complexes to understand the reaction pathways of this degradation process. DFT calculations have been performed to investigate the adsorption of acetate and acetic acid on ZnO clusters and the formation of Zn-acetate complexes. Carboxylic acids with longer alkyl chains have then been investigated as more realistic models of fatty acids. DFT calculations using a periodic ZnO slab have been performed to compare the obtained results at different levels of theory. Optimization calculations and formation energies of ZnO@carboxylate coupled systems and the thermodynamics leading to possible degradation products have been computed. Our results highlight the potential of DFT calculations for better understanding paint degradation with the aim of strengthening strategies of paintings. In photocatalysis, reactions can take place using light and a semiconductor: in this mechanism, an electron-hole pair is generated upon exposure of a semiconductor material to light, then the excited electron is used to reduce an acceptor species while the hole can simultaneously oxidize a donor species. The photocatalytic properties of TiO2 make it an ideal photocatalyst. It displays high bandgap energy and is known to make photocatalytic degradation process inexpensive and easy under sunlight. ZnO has also shown immense potential as photocatalysts and exhibits similar properties to TiO2. This work provides insight into the effects of photocatalysis to degrade coronavirus using TiO2 and ZnO metal oxide semiconductors. In this preliminary study, we focused on the interaction between TiO2 / ZnO and phospholipid models which assemble the environment of the coronavirus and could adsorb on the surface, employing different models and methods to calculate the energy associated to the adsorption of phospholipid at the metal oxide surface.La présente thèse étudie les oxydes métalliques et leur engagement dans les différents domaines. Nous avons concentré nos travaux sur les domaines de la géochimie environnementale, du patrimoine culturel et de la photocatalyse basée sur les interactions des oxydes métalliques. Géochimie environnementale. Les ZnO sont des systèmes courants présents dans divers contextes et également des systèmes modèles largement étudiés. Les nanoparticules de ZnO se trouvent dans le sol et l'eau, il est donc important d'étudier le devenir et le comportement de ce matériau dans l'environnement, et les isotopes sont des outils efficaces pour atteindre cet objectif. Des simulations informatiques peuvent compléter l'analyse directe des matériaux de ces systèmes. En particulier, nous avons concentré notre étude théorique sur l'évaluation de l'effet de surface sur la signature isotopique. Les nanoparticules de ZnO ont-elles une composition isotopique de Zn différente de celle des cristaux de ZnO en vrac dans des conditions d'équilibre ? Afin de répondre à cette question, nous avons effectué des calculs de structure et de fréquence basés sur la DFT sur différents modèles structurels. Les propriétés isotopiques sont ensuite déterminées à partir des fréquences vibrationnelles. Trois types de modèles structuraux ont été considérés : la structure brute du ZnO, les surfaces des dalles (1 0 1 ¯ 0) et (2 1 ¯ 1 ¯ 0), et une nanoparticule modèle. Les résultats obtenus permettent de discuter de l'effet de surface et des propriétés isotopiques des nanoparticules de ZnO. Héritage culturel. Des stratégies avancées de modélisation informatique ont été appliquées au patrimoine culturel pour comprendre les processus de dégradation des matériaux de peinture. La dégradation du ZnO conduit à la formation de complexes d'ions Zn et d'acides gras. S'agissant d'un problème sérieux affectant l'apparence des peintures à l'huile, il est pertinent de caractériser la structure de ces complexes pour comprendre les voies réactionnelles de ce processus de dégradation. Des calculs DFT ont été effectués pour étudier l'adsorption d'acétate et d'acide acétique sur des amas de ZnO et la formation de complexes Zn-acétate. Les acides carboxyliques avec des chaînes alkyles plus longues ont ensuite été étudiés comme modèles plus réalistes d'acides gras. Des calculs DFT utilisant une dalle périodique de ZnO ont été effectués pour comparer les résultats obtenus à différents niveaux de théorie. Les calculs d'optimisation et les énergies de formation des systèmes couplés ZnO@carboxylate et la thermodynamique conduisant à d'éventuels produits de dégradation ont été calculés. Nos résultats mettent en évidence le potentiel des calculs DFT pour mieux comprendre la dégradation des peintures dans le but de renforcer les stratégies des peintures. En photocatalyse, des réactions peuvent avoir lieu en utilisant la lumière et un semi-conducteur : dans ce mécanisme, une paire électron-trou est générée lors de l'exposition d'un matériau semi-conducteur à la lumière, puis l'électron excité est utilisé pour réduire une espèce acceptrice tandis que le trou peut simultanément s'oxyder une espèce donneuse. Les propriétés photocatalytiques du TiO2 en font un photocatalyseur idéal. Il affiche une énergie de bande interdite élevée et est connu pour rendre le processus de dégradation photocatalytique peu coûteux et facile sous la lumière du soleil.[...