Multimetallic Oxynitrides Nanoparticles for a New Generation of Photocatalysts

A versatile synthetic strategy for the preparation of multimetallic oxynitrides has been designed and here exemplarily discussed considering the preparation of nanoscaled zinc\u2013gallium oxynitrides and zinc\u2013gallium\u2013indium oxynitrides, two important photocatalysts of new generation, which proved to be active in key energy related processes from pollutant decomposition to overall water splitting. The synthesis presented here allows the preparation of small nanoparticles (less than 20 nm in average diameter), well-defined in size and shape, yet highly crystalline and with the highest surface area reported so far (up to 80 m2 g 121). X-ray diffraction studies show that the final material is not a mixture of single oxides but a distinctive compound. The photocatalytic properties of the oxynitrides have been tested towards the decomposition of an organic dye (as a model reaction for the decomposition of air pollutants), showing better photocatalytic performances than the corresponding pure phases (reaction constant 0.22 h 121), whereas almost no reaction was observed in absence of catalyst or in the dark. The photocatalysts have been also tested for H2 evolution (semi-reaction of the water splitting process) with results comparable to the best literature values but leaving room for further improvement

Persistence on therapy and propensity matched outcome comparison of two subcutaneous interferon beta 1a dosages for multiple sclerosis

To compare treatment persistence between two dosages of interferon β-1a in a large observational multiple sclerosis registry and assess disease outcomes of first line MS treatment at these dosages using propensity scoring to adjust for baseline imbalance in disease characteristics. Treatment discontinuations were evaluated in all patients within the MSBase registry who commenced interferon β-1a SC thrice weekly (n = 4678). Furthermore, we assessed 2-year clinical outcomes in 1220 patients treated with interferon β-1a in either dosage (22 µg or 44 µg) as their first disease modifying agent, matched on propensity score calculated from pre-treatment demographic and clinical variables. A subgroup analysis was performed on 456 matched patients who also had baseline MRI variables recorded. Overall, 4054 treatment discontinuations were recorded in 3059 patients. The patients receiving the lower interferon dosage were more likely to discontinue treatment than those with the higher dosage (25% vs. 20% annual probability of discontinuation, respectively). This was seen in discontinuations with reasons recorded as “lack of efficacy” (3.3% vs. 1.7%), “scheduled stop” (2.2% vs. 1.3%) or without the reason recorded (16.7% vs. 13.3% annual discontinuation rate, 22 µg vs. 44 µg dosage, respectively). Propensity score was determined by treating centre and disability (score without MRI parameters) or centre, sex and number of contrast-enhancing lesions (score including MRI parameters). No differences in clinical outcomes at two years (relapse rate, time relapse-free and disability) were observed between the matched patients treated with either of the interferon dosages. Treatment discontinuations were more common in interferon β-1a 22 µg SC thrice weekly. However, 2-year clinical outcomes did not differ between patients receiving the different dosages, thus replicating in a registry dataset derived from “real-world” database the results of the pivotal randomised trial. Propensity score matching effectively minimised baseline covariate imbalance between two directly compared sub-populations from a large observational registry

Spectroscopy for the characterization of materials and cultural heritage

The use of radiation or of particles as probes to investigate the matter by spectroscopic techniques is one of the main ways followed by researchers to define its structure and properties. Furthermore, there are several mechanisms of interaction able to provide indirect information about composition, bonds, and interactions, which describe the state of the system under investigation by proposing a proper model. For this reason, Spectroscopy can be considered a powerful tool for the study of materials by the characterization of the features influencing the properties. In the last years, the application fields of spectroscopic techniques was extended from synthetic materials also to the study of goods of interests in the field of cultural heritage, more complex systems for variable composition, and less or absent prior knowledge, which requires non-invasively investigation as the main demand to preserve the integrity of the object. The chemical-physical analysis can reveal, for example, information about the production of the object (raw materials and technology of the manufacture), the aging (the chemical processes involved due to the interaction with the environment permanence in the time) and the conservation state (to tailor the actions in the restoration work or to preserve the object for future) [1]. There are some limits to the amount of information available from spectroscopy so it is necessary to develop approaches to standardize the setup and the methods for investigating a kind of object, extracting the highest amount of information with the lowest impact [2]. My research activity focused on that, developing new approaches devoted mainly to the study of archaeological metals and paintings. During the presentation, firstly a brief description of the research field will be provided, then some cases studios will be described in order to show the potentiality of spectroscopy applied to cultural heritage. One of the study regarding two Montefortino helmets [3] summarize how X-ray and neutron based spectroscopies permits to describe the metal of the goods from the production to the corrosion

Physico-chemical approaches in materials investigations

Physico-chemical characterization is the keystone to fully understand the material properties. This topical issue has collected almost 30 contributions reflecting the latest developments on the topic. It includes, but is not limited to spectroscopic characterization, characterisation of materials by using neutrons as source, development of alternative synthetic routes of nanoparticles, microwave assisted synthesis, preparation of polymeric nanocomposites, archaeometric investigation of ancient materials

Synthesis and antibacterial activity of iron-hexacyanocobaltate nanoparticles

This paper deals with the synthesis and characterization of iron-hexacyanocobaltate (FeHCC) and its antibacterial properties. The nanoparticles were prepared by a facile co-precipitation technique. Crystal structure, particle morphology, and elemental composition were determined using X-ray Powder Diffraction, X-ray fluorescence spectroscopy, Transmission Electron Microscopy (TEM), and Infrared Spectroscopy (IR). The antibacterial activity of the FeHCC nanoparticles was tested against Escherichia coli and Staphylococcus aureus as models for Gram-negative and Gram-positive bacteria, respectively, by bacterial counting method and microscopic visualization (TEM, FEG-SEM, and fluorescence microscopy). The results showed that the FeHCC nanoparticles bind to the bacterial cells, inhibit bacterial growth in a dose- and time-dependent manner, inducing a loss of the membrane potential, the production of reactive oxygen species and the release of macromolecules (nucleic acids and proteins) in the extracellular environment. To the best of our knowledge, this is the first study reporting the antimicrobial effects of metal-hexacyanometallates suggesting practical uses of these materials in different areas, such as self-cleaning surfaces or food packaging

Effect of surface impurities on downconversion luminescence of Pr-3(+), Yb-3(+) activated SrF2 nanoparticles

Pr3+,Yb3+ activated SrF2 nanoparticles synthesized by low-temperature hydrothermal method were studied. The composition and size of nanoparticles were intentionally changed by controlling synthesis conditions. After structural and morphological characterization, the spectroscopic properties of the nanoparticles were analyzed in the visible and near infrared spectra ranges. The results show correlation between the gradual change of the amount of carboxylate and hydroxyl moieties on the nanoparticle surface, varied by the size nanoparticles and the quenching of the luminescence. The size-related amount of surface quenchers is strongly connected to the decrease of the downconversion efficiency

FIRST DISCOVERY OF ORICHALCUM INGOTS FROM THE REMAINS OF A 6TH CENTURY BC SHIPWRECK NEAR GELA (SICILY) SEABED

Ingots recently recovered from the seabed near Gela, a major harbour of Sicily, reveal an unexpected side of ancient metallurgy. The ingots were found near remains of a ship and earthenware dated around the end of the VI century BC and probably coming from the eastern Mediterranean and the Aegean sea. The ingots were analysed by means of X-Ray Fluorescence spectroscopy via a portable spectrometer. Results indicate that they are mostly consist of copper and zinc although many of them have a significant amount of lead. This alloy is nowday called brass, but in ancient time it was know as orichalcum, one of the rarest and most precious alloy along with gold and silver. Only small items of orichalcum dating before Christ were found so far. The visual examination corroborate by evaluation of dimensions and weight, are consistent with the dating hypothesis and reveals important information about the casting production. The discovery of more than twenty-two kilos of ingots is extraordinary: a first ray of light upon a forgotten technology, which involved also smelter plants (maybe more than one), a commercial network, and a number of end users, who certainly appreciated the properties of shining orichalcum: ductility, mechanical strength, durability, and value