Wetting Modification by Photocatalysis: A Hands-on Activity To Demonstrate Photoactivated Reactions at Semiconductor Surfaces

We present a hands-on activity designed for advanced physical chemistry courses for Master\u2019s students on the application of photocatalysis to the modification of the surface properties of a semiconductor (titanium dioxide). The wetting properties of TiO2 films, deposited from commercial powders, are studied before and after UV irradiation. Irradiation-induced superhydrophilicity is exploited to provide antifogging properties. The TiO2 films are then functionalized with a perfluorinated alkylsilane to impart superhydrophobicity and subsequently lithographed by irradiation through a photomask: the photocatalytic degradation of the organic chains in the irradiated areas leads to a wetting contrast that can be revealed using dye solutions. This experience can be easily adapted to be suited for undergraduates or high-school students as well as to demonstrations for science festivals

How to Show a National Cuisine: Food and National Identities in the Masterchef Kitchen

In this article, I analyse some aspects that characterise the relationship between food preparation practices and national identities in the first American, Spanish and Italian edition of the Masterchef international television format. The article is divided into two parts: in the first one, I perform a comparative analysis of the representation and the spectacularization of national identities in terms of how they are conveyed in the Masterchef kitchens. Conversely, in the second part, I highlight the aspect of self-storytelling through a specific perspective on the work of the chef and its media representation by relating it to the economic and employment crisis that has affected the West at various levels in recent years. DOI: 10.5901/ajis.2015.v4n2p25

Novel platinum agents and mesenchymal stromal cells for thoracic malignancies : state of the art and future perspectives

Introduction: Non-small cell lung cancer and malignant pleural mesothelioma represent two of the most intriguing and scrutinized thoracic malignancies, presenting interesting perspectives of experimental development and clinical applications. Areas covered: In advanced non-small cell lung cancer, molecular targeted therapy is the standard firstline treatment for patients with identified driver mutations; on the other hand, chemotherapy is the standard treatment for patients without EGFR mutations or ALK rearrangement or those with unknown mutation status. Once considered an ineffective therapy in pulmonary neoplasms, immunotherapy has been now established as one of the most promising therapeutic options. Mesenchymal stromal cells are able to migrate specifically toward solid neoplasms and their metastatic localizations when injected intravenously. This peculiar cancer tropism has opened up an emerging field to use them as vectors to deliver antineoplastic drugs for targeted therapies. Expert opinion: Molecular targeted therapy and immunotherapy are the new alternatives to standard chemotherapy. Mesenchymal stromal cells are a new promising tool in oncology and\u2014although not yet utilized in the clinical practice, we think they will represent another main tool for cancer therapy and will probably play a leading role in the field of nanovectors and molecular medicine

NANOSTRUCTURED OXIDES AS LEADING ACTORS FOR ENVIRONMENTAL REMEDIATION, SMART SURFACES AND ENERGY APPLICATIONS

In the last decades, metal oxides have been widely employed in the field of nanotechnology, thanks to their physicochemical characteristics. In fact, oxidic compounds can be exploited for manifold applications due to their chemical, thermal and mechanical stability, the low-cost, the low- or non-toxicity. Moreover, the possibility to easily obtain metal oxides as nano or nanostructured powders together with their high reactivity, mainly due to the presence of polar hydroxyl groups populating the surface, have always attracted the scientific community interested in the field connected to catalysis. Among the most adopted metal oxide in materials science, titanium dioxide (TiO2), tungsten oxide (WO3), silicon dioxide (SiO2) and aluminium oxide (Al2O3) can be mentioned. Actually, the properties of the metal oxides strictly depend on their electronic structure. Some of them are semiconductors (e.g. TiO2 and WO3), while others are insulators (e.g. SiO2 and Al2O3), in dependence on the width of the energy gap between the valence and the conduction bands. Semiconductors, thanks to the relatively small band gap with respect to insulators, can be exploited for a wide number of recently developed applications in chemistry, physics and materials science. One of these applications exploited light with suitable wavelength for the promotion of electrons from the valence band to the conduction band, in order to promote reduction or oxidation reactions. This field of the physical chemistry is called photocatalysis and is the main focus of this Thesis. Photocatalysis, especially if titanium dioxide-based, can be useful for promoting a wide range of chemical reactions, e.g. hydrogen and fuels production, CO2 reduction, metal reduction/oxidation. In the last decades, photocatalysis was also proposed as an innovative and effective environmental remediation technique for the oxidative degradation of organic compounds constituting atmospheric or water pollution. In fact, photocatalysis can be able, differently from traditional remediation techniques (e.g. biological treatments, adsorption by activated carbon, \u2026), to completely degrade the pollutants and their oxidation intermediates and by-products to harmless compounds (water, CO2, and, in case, inorganic salts). Nonetheless, photocatalysis suffers from critical issues which, nowadays, still prevent its use on a large utility-scale. Among these, the low quantum yields and, thus, efficiency of the photocatalytic process with respect to the light irradiation adopted to activate the photocatalyst, the need of UV light to activate large band gap semiconductors, such as TiO2, and the high costs for the removal of the photocatalyst from the polluted effluent once the remediation treatment has been performed. This Thesis is divided into three different parts, on the grounds of the materials studied and their final application. In Part I (Chapters 1\u20137), TiO2-based materials for photocatalysis, variably modified and engineered by adopting different strategies for the promotion of specific properties, are reported. In Part II (Chapters 8\u201311), the preparation and the characterization (also by means of electrochemical techniques) of silica and titania films with tailored porosity and surface properties are presented. Eventually, Part III (Chapters 12\u201313) reports the study of active materials for heterogeneous catalysis and photo-electrocatalysis in the framework of the research of new energy sources and novel materials with energy conversion applications. More in detail, Part I of this Thesis (Chapters 1\u20137) was devoted to the study of TiO2-based photocatalysts for application in the field of pollutants degradation (both in the gas and the liquid phase) and to the effort to overcome the typical issues of photocatalysis by adopting different approaches (e.g. doping, co-doping, coupling with smaller band gap semiconductors, development of floating device). Moreover, photocatalysis was also exploited for surface modification / lithographic purposes and for photoelectrochemical applications, which will be described in Chapters 11 and 13, respectively. Firstly, the characterization and the photocatalytic activity tests of differently prepared TiO2 nanostructured samples were performed. By varying the calcination temperature (from 300 to 600 \ub0C) different phase composition and morphologies were obtained and the efficiency towards tetracycline degradation was thus optimized for the laboratory synthesized TiO2 samples. Tetracycline is an antibiotic compound of recent interest as a micropollutant of wastewaters and surface waters, due to its wide use for both human and animal treatments. In Chapter 1, the development of two different low-cost TiO2 immobilized systems is also reported: alumina macroscopic supports were adopted together with a prepared titania sol and an easy deposition technique, revealing good activity, as well as resistance, towards tetracycline degradation. In order to develop accessible active devices through the photocatalyst immobilization on a support, titanium meshes were also employed (Chapter 2). However, differently from the work reported in Chapter 1, in Chapter 2, the focus of the work was addressed to the study of the photocatalytic environment, in terms of water medium composition. The photocatalytic degradation of four different organic compounds (tetracycline, paracetamol, caffeine and atenolol) belonging to the class of pharmaceutics and personal care products (PPCPs) and classified as emerging contaminants was tested both for the single pollutants and for their mixture. The role of the solution composition and especially the role of electrolytes, were also studied by performing photocatalytic tests in commercial and simulated drinking waters. This work falls within the framework of the necessity to comprehend the potential of photocatalysis even in the case of water effluent constituted by complex matrix in terms of solvent composition and presence of many different pollutants at low concentration ranges. In fact, the presence of several organic compounds to be degraded, as well as the electrolytes present in the water matrix and its composition and physicochemical properties can deeply affect the efficiency of the photocatalytic process, the adsorption and the degradation mechanisms. Then, in the following three Chapters (3\u20135), the effects of doping and co-doping of titanium dioxide with metal and non-metal species, mainly in order to promote the activity of TiO2 under visible light, but also to enhance its efficiency were explored. In-depth characterizations were performed on N,Ta/Nb titania samples from the structural, morphological, spectroscopic and electronic point of view (by XRPD, surface area and porosity, XPS, EPR and DRS analyses) to comprehend the modifications provided by the guest species on the photocatalysts and how this could reflect on the photocatalytic performance. Moreover, a combined experimental / theoretical approach was followed for a better comprehension, by means of DFT simulations. The samples were finally tested towards the photocatalytic degradation of ethanol in the gas phase. The sole Ta doping on differently synthesized TiO2 samples and for paracetamol degradation was also studied, with particular emphasis on the photocatalyst surface acidity (performing titrations of the photocatalyst acid sites by phenylethylamine adsorption in liquid-solid phase), its stability in suspension and the recognition of degradation intermediates (by gas chromatography \u2013 mass spectroscopy analyses) possibly responsible for the photocatalytic performance among the different samples. This permitted to evaluate parameters which are often disregarded but become pivotal when photocatalytic degradations in the aqueous phase are considered. Sn and Zn were also investigated as elements able to strongly modify the structural characteristics of TiO2 samples, mainly in terms of phase composition and surface defectivity (recognized by HR-TEM, XPS and electrophoretic analyses). The adopted amount of metal modifiers during synthesis also allowed the possible formation of composite oxidic materials to be observed and its effects to be studied. Moreover, the concomitant use of N as a guest species able to promote the visible light absorption, allowed superior effects in the visible light harvesting to be recognized and enhanced activity under visible irradiation to be proved. The effect of the guest species on the reaction mechanism was also investigated by mass spectroscopy analyses, proving significant variations in the case of Zn promoted samples, with respect to pristine, N- and Sn- modified photocatalysts. This work paved the way for the last two Chapters of Part I of the Thesis, regarding composite photocatalytic materials, both in the case of oxidic composites (Chapter 6) and inorganic-organic ones (Chapter 7). In the former case, WO3 was selected as a minority photocatalyst together with TiO2 in order to comprehend the effects provided by a sort of co-photocatalyst in the degradation of tetracycline (in the liquid phase) and ethanol (in the gas phase). Also in this case, the differences pertaining the degradation mechanisms reported for both reactions were reconnected to the specific modifications of the bulk and the surface properties of TiO2 by WO3 species. In the latter case, instead, a novel methyl methacrylate-based ter-polymer, with specific dual wetting properties (thanks to the use of a fluorinated co-monomer) when reduced in foils, was adopted to assemble a floating, transparent and photocatalytically active device. For this purpose, the physicochemical characteristics of the ter-polymer were finely tailored and, successively, SiO2 (with adhesion and protection tasks) and TiO2 (photoactive) layers were deposited from home-made colloidal solutions by spray-coating technique. The photocatalytic activity of this organic-inorganic multilayer device was successfully tested towards the degradation of both atmosphere and water contaminants, in the context of its possible use for remediation from organic substances and their vapours from polluted large water basins. In these cases, in fact, the use of nanostructured powders, even as immobilized systems, should be avoided for issues related to photocatalyst removal, while the floatability promotes light harvesting. Throughout Part II of the Thesis, instead, the wide range of applicability of oxide nanomaterials obtained as films is reported. In fact, oxidic compounds such as SiO2 and TiO2 can be easily obtained as nanometric or micrometric films deposited on supports (e.g. glass slide, silicon wafer, conductive glass) from colloidal solutions or powder suspensions. In this regard, in this Thesis, SiO2 films were exploited for understanding the effects provided by surface or morphology modifications from a fundamental point of view. For this purpose, an intense use of electrochemical characterization techniques (cyclic voltammetry and electrochemical impedance spectroscopy) and surface wettability analyses by contact angle measurements was done. In Chapter 8 the effects provided by the deposition of an insulating layers of SiO2 onto a conductive glass were studied in terms of mass transport and charge transfer phenomena. By varying the thickness of these devices, which actually can be described as modified electrodes, different behaviours in the voltammetric signal were recorded, despite their strong insulating character. The voltammogram shape variations were interpreted in the light of previous theoretical studies reporting simulations of cyclic voltammetry analyses for electrodes modified by deposition of electroinactive layers. For the first time, the outcomes only reported on the basis of theoretical simulations were experimentally observed. The work presented in the Chapter 8 can be also seen as introductory to the following one. In fact, on the basis of the results obtained by electroinactive layers modified electrodes, especially regarding the variation of the diffusion and transport phenomena to the electroactive surface, porous SiO2-based electrodes with peculiar properties were developed. These electrodes, characterized by controlled mesoporosity due to the preparation involving nanometric polystyrene latex beads as solid templating agents, were deeply characterized under the physicochemical point of view (by SEM, FE-SEM, AFM, UV-vis spectroscopy, water contact angle measurements) and exploited for sensing applications. In particular, thanks to its morphological, surface charge and wetting properties, the modified electrode proved effective in the selective detection of dopamine in the presence of mucin as interfering agent. Dopamine is a neurotransmitter whose quantification in biofluids is pivotal for the diagnosis of the Parkinson\u2019s disease, while mucin is a large dimension protein which can interfere in dopamine detection, as actually proved in the case of a bare electrode. The development of these tailored morphologies is to be seen in the context of the research devoted to the preparation of high selective and antifouling sensors. High selectivity and antifouling (i.e. reliable quantifications together with long electrode durability) are considered major issues nowadays in the field of electroanalysis. In the following two Chapters, instead, the behaviour of organic-inorganic hybrids is reported. In Chapter 10, SiO2 substrates were adopted for surface modification by alkylsilanes, molecules easily reacting with oxidic surfaces thus modifying their wettability, even for obtaining superhydrophobic surfaces. A vast number of characterizations (solid state NMR, surface free energy analyses, FTIR, electrochemical techniques) allowed the behaviour from a molecular point of view of alkylsilanes chemisorbed on a silica surface to be understood. In Chapter 11, in the framework of a hands-on activity for students and with both research and didactic purposes, the wetting modifications of TiO2 films from suprhydrophilicity to superhydrophobicity were investigated by means of functionalization by alkylsilanes as well as of photocatalysis. In this case, the formation of organic-inorganic hybrids as films was exploited not only to obtain superhydrophobic surfaces but also for patterning applications thanks to photocatalysis. In fact, by irradiating such a modified TiO2 surface by UV light, the photocatalytic process can be activated for selectively degrade the functionalizing molecule and create patterned surfaces characterized by wetting contrasts. This approach is generally called photocatalytic lithography and falls in the framework of surface wettability modifications by functionalizing oxidic compounds with organic amphiphilic molecules. In the last decades, these approaches have been receiving great interest for their everyday-life impacting aspects: self-cleaning, anti-stain and anti-corrosion surfaces are just few examples of the applicability of these complex materials which can be used for new technologies such as smart glasses, pollution remediating buildings, long-lasting ship hulls. Eventually, in the last part of the Thesis, studies regarding the preparation on composite materials for energy-related applications are presented. In Chapter 12, SiO2/Al2O3 powders with different relative composition were adopted as catalytic supports for the hydrodeoxygenation reaction of guaiacol. Ni was selected as active catalyst the effects of its concentration onto the support were explored. The guaiacol hydrodeoxygenation reaction is often taken into account as a model reaction for studying the upgrading of bio-oils. Bio-oils are the product of the conversion of lignocellulosic biomass, a renewable source of energy which received great attention in the last few years, in the context of the progressive depletion of fossil fuels and the incumbent need to find new and renewable energy sources. In the last Chapter, instead, colloidal synthesis approaches were adopted to obtain oxidic heterojunctions for photoelectrochemical applications. The two components of these heterojunctions were WO3 and copper vanadate (Cu2V2O7), in different ratios. Cu2V2O7 is a small band gap semiconductor which enables the heterojunction to be active under visible light and to promote charge transfer phenomena, favourable for enhancing the photocatalytic efficiency with respect to bare WO3. A vast characterization was performed adopting HR-TEM, in-situ XRD, photoluminescence and nanosecond transient absorption spectroscopies, in order to understand the physicochemical phenomena occurring at the interface between the two oxides and to optimize the heterojunction composition for the final application

Informal childcare arrangements: a comparison between Italians and migrants

As migrants settle in their destination country, for those who reunited the family or after childbirth childcare becomes a priority. Most studies on migrants’ childcare arrangements have focused on parental use of formal childcare rather than on different informal childcare solutions by analysing only families with preschool-age children. Italy poses an interesting case study because its welfare system is characterised by a familistic model of care, based on solidarity between generations. In familistic countries, migrants’ childcare solutions are more constrained. In this study, we analysed differences in informal childcare needs and arrangements for children younger than 14 between Italians and migrants from different countries of origin. We merged two surveys conducted by the Italian National Statistics Institute in 2011–2012: ‘Social Condition and Integration of Foreign Citizens’, a sample of households with at least one migrant with foreign citizenship, and ‘Multiscopo—Aspects of Daily Life’, a sample of households in Italy. We found that household composition and parents’ employment status play an important role in shaping informal childcare arrangements. Overall, migrants are less likely to use informal childcare, especially grandparents, than Italians but when they do, they rely more on other relatives and non-relatives than Italians. Moreover, differences emerge across migrant subgroups. This study is the first in Italy to contribute to an understanding of the role of migrant status in determining parents’ childcare arrangements for children up to 13 years

Dynamics and tolerance to external optical feedback of III-V/Si hybrid lasers with dispersive narrowband mirror

We report how external cavity III-V/Si hybrid lasers operate in regimes of ultra-damped relaxation oscillations or in unstable regimes as consequence to the dispersive mirror, non-zero linewidth enhancement factor and four-wave mixing in the gain medium. Tolerance to external optical feedback is also discussed

Mesoporous silica networks with improved diffusion and interference-rejecting properties for electroanalytical sensing

Mesoporous silica materials characterized by well-ordered microstructure and size- and shape-controlled pores have attracted much attention in the last years. These systems can be used for the development of functional thin films for advanced applications in catalysis and electrocatalysis, sensors and actuators, separation techniques, micro- and nano-electronic engineering [1-2]. In this work, \u201cinsulating\u201d and mesoporous silica films were prepared by spin coating a home-made silica sol on a cleaned ITO glass support. The mesoporosity was controlled by the use of Polystyrene (PS) latex beads with different dimensions (30-60-100 nm) as template. The number of successive multi-layer depositions was varied (1-2-3-5 layers) and after the template removal, stable, homogeneous and reproducible transparent films were obtained, characterized by an interconnected porous structure. The morphological features and the physicochemical and optical properties of the films and/or sol-precursors were studied by DLS, FE-SEM, AFM, UV-vis transmittance spectroscopy and wettability analyses. Moreover, a deep electrochemical characterization was also performed by Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS). In particular, the use of two redox mediator probes [(K4Fe(CN)6) and (Ru(NH3)6Cl3)], presenting opposite charge and different diffusional behaviour, allowed the comprehension of the mass transport and charge transfer phenomena, evidencing the effects of spatial confinement and charge selection. In the case of \u201cinsulating\u201d films prepared without the use of PS latexes, we proved an experimental evidence for theoretical models [3] concerning electroinactive layer-modified electrodes, with a scan-rate-dependent variation of the CV shape due to a progressive increase in the diffusion coefficient inside the insulating layer. A complex balance between diverging effects (higher hydrophilicity and insulating behavior effects of silica) when increasing the numbers of layers was also observed [4]. In the case of mesoporous layers, a better electrochemical response of smaller pores and of thicker layers was found, due to two main cooperative phenomena: i) a diffusion modification from fully planar to radial-convergent at the pore-silica interface due to surface porosity; ii) the presence of pores in a hydrophilic matrix which leads to a capillary pull effects, stronger in the case of smaller hydrophilic pores. The easiness of preparation and the interesting properties of these devices pave the way towards their use in many fields, particularly trace electroanalysis in real matrices. In fact, for example, the porous and properly charged network is able to exclude interfering macromolecules (mucin in our case), preventing electrode biofouling and enhancing the performances of the sensor towards dopamine detection. References [1] M. Ogawa, Chem. Rec. 17 (2017) 217-232. [2] A. Walcarius, Chem. Soc. Rev. 42 (2013) 4098-4140. [3] D. Menshykau, R.G. Compton, Langmuir 25 (2009) 2519\u20132529. [4] V. Pifferi, L. Rimoldi, D. Meroni, F. Segrado, G. Soliveri, S. Ardizzone, L. Falciola, Electrochem. Commun. 81 (2017) 102-105

Intestinal microbial communities of rainbow trout (Oncorhynchus mykiss) may be improved by feeding a Hermetia illucens meal/low-fishmeal diet.

With demands and reliance on aquaculture still growing, there are various challenges to allow sustainable growth and the shift from fishmeal (FM) to other protein sources in aquafeed formulations is one of the most important. In this regard, interest in the use of insect meal (IM) in aquafeeds has grown rapidly. Accordingly, the aim of the present study was to assess the effects of dietary IM from Hermetia illucens (Hi) larvae included in a low-FM diet on gut microbial communities of rainbow trout (Oncorhynchus mykiss), in terms of both composition and function of microbiome. A feeding trial was conducted using 192 trout of about 100-g mean initial weight. Fish were fed in quadruplicate (4 tanks/diet) for 131 days with two diets: the control (Ctrl) contained 20% of FM as well as other protein sources, whereas the Hi diet contained 15% of Hi larvae meal to replace 50% of the FM contained in the Ctrl diet. High-throughput sequencing of 16S rRNA gene was used to identify the major feed and gut bacterial taxa, whereas Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) analysis was performed on gut bacterial genomes to identify the major active biological pathways. The inclusion of IM led to an increase in Firmicutes, mainly represented by Bacilli class and to a drastic reduction of Proteobacteria. Beneficial genera, such as Lactobacillus and Bacillus, were enriched in the gut of fish fed with the Hi diet, whereas the number of bacteria assigned to the pathogenic Aeromonas genus was drastically reduced in the same fish group. The metagenome functional data provided evidence that dietary IM inclusion can shape the metabolic activity of trout gut microbiota. In particular, intestinal microbiome of fish fed with IM may have the capacity to improve dietary carbohydrate utilization. Therefore, H. illucens meal is a promising protein source for trout nutrition, able to modulate gut microbial community by increasing the abundance of some bacteria taxa that are likely to play a key role in fish health

Migrants' choices pertaining to informal childcare in Italy and France: A complex relationship between the origin and destination countries

Childcare is a need that inevitably emerges once migrants establish themselves and their families in their destination country. However, migrants' use of informal childcare still constitutes an under‐researched phenomenon. Using data from the ‘Social Condition and Integration of Foreign Citizens’ survey (2011–2012) for Italy and the ‘Trajectoires et Origines’ survey (2008–2009) for France, this paper examines differences between migrants living in the two countries in terms of their use of informal childcare and, more specifically, their informal childcare arrangements. We employ a comparative analysis because we hypothesised that parental choices would depend on the migrants' region of origin, the institutional context of their destination country and the interplay between these two elements. The results suggest that migrants' choices stem from a complex relationship between the norms and beliefs of the country of origin and those in the destination country, which are generally characterised by different family policies and levels of childcare availability. We show that the use of informal childcare is higher among migrants in Italy than it is among those in France, even among migrants from the same region of origin. The results also suggest that the use of particular informal childcare arrangements varies by region of origin regardless of destination country, supporting the hypothesis that migrants' cultural values and beliefs play a critical role in determining childcare arrangements. Finally, we demonstrate that household composition and parents' occupational status strongly influence migrants' childcare choices

The effects of dietary insect meal from Hermetia illucens prepupae on autochthonous gut microbiota of rainbow trout (Oncorhynchus mykiss)

This study evaluated the effects of dietary insect meal from Hermetia illucens larvae on autochthonous gut microbiota of rainbow trout (Oncorhynchus mykiss). Three diets, with increasing levels of insect meal inclusion (10%, 20%, and 30%) and a control diet without insect meal were tested in a 12-week feeding trial. To analyze the resident intestinal microbial communities, the Illumina MiSeq platform for sequencing of 16S rRNA gene and QIIME pipeline were used. The number of reads taxonomically classified according to the Greengenes database was 1,514,155. Seventy-four Operational Taxonomic Units (OTUs) at 97% identity were identified. The core of adhered intestinal microbiota, i.e., OTUs present in at least 80% of mucosal samples and shared regardless of the diet, was constituted by three OTUs assigned to Propiobacterinae, Shewanella, and Mycoplasma genera, respectively. Fish fed the insect-based diets showed higher bacterial diversity with a reduction in Proteobacteria in comparison to fish fed the fishmeal diet. Insect-meal inclusion in the diet increased the gut abundance of Mycoplasma, which was attributed the ability to produce lactic and acetic acid as final products of its fermentation. We believe that the observed variations on the autochthonous intestinal microbiota composition of trout are principally due to the prebiotic properties of fermentable chitin