Reaction with Water Vapor Defines Surface Reconstruction and Membranolytic Activity of Quartz Milled in Different Molecular Environments.

Industrial processing of quartz (SiO) and quartz-containing materials produces toxic dust. Fracturing quartz crystals opens the Si‒O bond and produces highly reactive surface species which mainly react with molecules like water and oxygen. This surface-reconstruction process forms silanol (Si‒OH) on the quartz surface, which can damage biological membranes under specific configurations.

Eco-friendly PVA-LYS fibers for gold nanoparticle recovery from water and their catalytic performance.

In this work, we grafted lysine on PVA electrospun fibers, using a green preparation technique. The resulting fiber mats were proposed for gold nanoparticles (AuNPs) removal from water. The efficiency of three fibers with different lysine amounts (10, 20, and 30%) was investigated.

Mercury and Organic Pollutants Removal from Aqueous Solutions by Heterogeneous Photocatalysis with ZnO-Based Materials.

The removal of four Contaminants of Emerging Concern, namely bisphenol A, sulfamethoxazole, diclofenac and benzotriazole; two odorous compounds, geosmin and 2-methylisoborneol, frequently detected in recirculating aquaculture systems; and Hg(II) was investigated using ZnO-based materials doped or co-doped with Ce and Cu under simulated solar radiation. Photocatalysts were synthetized via a hydrothermal route and their efficiency was assessed by changing some operational parameters in different water matrices of increasing complexity. The mixture of contaminants was successfully degraded in just 1 h, while the complete mineralization was achieved in a few hours; experiments performed in an actual aquaculture water confirmed the efficiency and broad versatility of the synthesized materials.

Surface species in direct liquid phase synthesis of dimethyl carbonate from methanol and CO: an MCR-ALS augmented ATR-IR study.

The reaction mechanism of dimethyl carbonate (DMC) production over ZrO from CO and CHOH is well-known, but the level of understanding has not improved in the last decade. Most commonly, the reaction mechanism has been explored in the gas phase, whilst DMC production occurs in the liquid phase. To overcome this contradiction, we exploited ATR-IR spectroscopy to study DMC formation over ZrO in the liquid phase.

Red Upconverter Nanocrystals Functionalized with Verteporfin for Photodynamic Therapy Triggered by Upconversion.

Upconversion (UC) nanoparticles characterized by red upconversion emission, particularly interesting for biological applications, have been prepared and subsequently modified by the covalent anchoring of Verteporfin (Ver), an FDA approved photosensitizer (PS) which usually exerts its photodynamic activity upon excitation with red light. ZrO was chosen as the platform where Yb and Er were inserted as the sensitizer and activator ions, respectively. Careful control of the doping ratio, along with a detailed physico-chemical characterization, was carried out.

Natural solar activation of modified zinc oxides with rare earth elements (Ce, Yb) and Fe for the simultaneous disinfection and decontamination of urban wastewater.

This study investigates the capability of modified zinc oxides (ZnO) with Ce, Yb and Fe towards the simultaneous inactivation of pathogenic bacteria (Escherichia coli, Enterococcus faecalis and Pseudomonas aeruginosa) and Contaminants of Emerging Concern (CECs, Diclofenac, Sulfamethoxazole and Trimethoprim) under natural sunlight. Several catalyst loads (from 0 to 500 mg/L) were assessed as proof-of principle in isotonic solution followed by the evaluation of organic matter effect in simulated and actual urban wastewater (UWW), using bare TiO-P25 as reference. The order of photocatalysts efficiency for both bacterial and CECs removal was: ZnO-Ce ≅ TiO-P25 > ZnO-Yb > ZnO-Fe > photolysis > darkness in all water matrices.

Nitrogen-Doped Zinc Oxide for Photo-Driven Molecular Hydrogen Production.

Due to its thermal stability, conductivity, high exciton binding energy and high electron mobility, zinc oxide is one of the most studied semiconductors in the field of photocatalysis. However, the wide bandgap requires the use of UV photons to harness its potential. A convenient way to appease such a limitation is the doping of the lattice with foreign atoms which, in turn, introduce localized states (defects) within the bandgap.

Zinc oxide hollow spheres decorated with cerium dioxide. The role of morphology in the photoactivity of semiconducting oxides.

The photochemical activity of the recently proposed CeO-ZnO photocatalytic material active under visible light has been improved by means of significant modifications of its morphology. A polymeric templating agent (Pluronic) has been used in the synthesis obtaining a particle morphology based on hollow spheres that is better defined in the case of high template concentration. The charge separation ability and the light-induced surface electron transfer under irradiation with visible polychromatic light in various ranges of wavelengths has been investigated by electron paramagnetic resonance.

The "Lab4treat" Outreach Experience: Preparation of Sustainable Magnetic Nanomaterials for Remediation of Model Wastewater.

The Lab4treat experience has been developed to demonstrate the use of magnetic materials in environmental applications. It was projected in the frame of the European project Mat4Treat, and it was tested several times in front of different audiences ranging from school students to the general public in training and/or divulgation events. The experience lends itself to discuss several aspects of actuality, physics and chemistry, which can be explained by modulating the discussion depth level, in order to meet the interests of younger or more experienced people and expand their knowledge.

Nitrogen-doped semiconducting oxides. Implications on photochemical, photocatalytic and electronic properties derived from EPR spectroscopy.

Engineering defects in semiconducting metal oxides is a challenge that remains at the forefront of materials chemistry research. Nitrogen has emerged as one of the most attractive elements able to tune the photochemical and photocatalytic properties of semiconducting oxides, boosting visible-light harvesting and charge separation events, key elements in promoting solar driven chemical reactions. Doping with nitrogen is also a strategy suggested to obtain p-type conduction properties in oxides showing n-type features in their pristine state and to impart collective magnetic properties to the same systems.

Electron magnetic resonance in heterogeneous photocatalysis research.

The contribution of electron magnetic resonance techniques, and in particular of CW-EPR, to the experimental research on photocatalytic phenomena is illustrated in this paper with selected examples. In the first part of the paper the role of EPR in unravelling the nature and the features of extrinsic point defects in semiconducting oxides is epitomized using the important example of the photoactive nitrogen center in various semiconducting oxides. In the second part we describe how EPR can monitor the processes that follow the initial photoinduced charge separation in photocatalysis, namely the stabilisation, migration and surface reactivity of electrons and holes.

An Easy Synthesis for Preparing Bio-Based Hybrid Adsorbent Useful for Fast Adsorption of Polar Pollutants.

For the first time, γ-AlO and Bio-Based Substances (BBS) hybrids (-BBS) were prepared through a simple electrostatic interaction occurring between alumina, used as a support, and BBS (Bio-Based Substance from composted biowastes) carrying positive and negative charges, respectively. We evaluated the optimal amount of BBS to be immobilized on the support and the stability of the resulting -BBS in order to use this novel hybrid material as an adsorbent for the removal of polar pollutants. Characterization was carried out by X-Ray Diffraction (XRD) for evaluating the crystal structure of the support, Fourier transform infrared spectroscopy (FT-IR) to evidence the presence of BBS on the hybrid material, thermogravimetric analysis (TGA) to measure the thermal stability of the hybrid materials and quantify the BBS amount immobilized on the support, N adsorption at 77 K for the evaluation of the surface area and porosity of the systems, Zeta potential measurements to evaluate the effect of BBS immobilization on the surface charge of the particles and choose the substrates possibly interacting with them.

Control of Membrane Fouling in Organics Filtration Using Ce-Doped Zirconia and Visible Light.

Membrane fouling has been a major issue in the development of more efficient water treatment processes. Specifically in surface waters filtration, organic matter, such as humic-like substances, can cause irreversible fouling. Therefore, this study evaluates the activity of a photocatalytic layer composed of Ce-doped zirconia nanoparticles in improving the fouling resistance during filtration of an aqueous solution of humic acid (HA).

Photoactivity properties of ZnO doped with cerium ions: an EPR study.

In the present study, we investigated the effect of cerium doping in zinc oxide matrix, used as photoactive material. Cerium ions into the matrix of ZnO can act like a 'trap' for the electrons, lowering the e /h recombination rate and so increasing the photocatalytic efficiency of the ZnO. We synthesised doped samples using a simple precipitation route.

[Factors influencing Intensive Care Units nurses in end-of-life decisions].

Objective: To identify the factors that influence the Intensive Care Unit nurse in the decision-making process in end-of-life situations.

Method: Ethnographic case study, which used the theoretical framework of medical anthropology. Data were collected through semi-structured interviews with 10 nurses.

Negotiated reorienting: a grounded theory of nurses' end-of-life decision-making in the intensive care unit.

Background: Intensive care units (ICUs) focus on treatment for those who are critically ill and interventions to prolong life. Ethical issues arise when decisions have to be made regarding the withdrawal and withholding of life-sustaining treatment and the shift to comfort and palliative care. These issues are particularly challenging for nurses when there are varying degrees of uncertainty regarding prognosis.

EPR study of the relationship between ultra high molecular weight polyethylene structure and radicals formed during irradiation with high energy sources.

Three different samples of ultra high molecular weight polyethylene have been irradiated with a high energy source (electron beam), and radicals have been generated. Different radical species have been assigned on the basis of their electron paramagnetic resonance spectra. Electron paramagnetic resonance data have been used also to evaluate the amount of each kind of radical that has been generated on different starting materials.

TiO2@CeOx core-shell nanoparticles as artificial enzymes with peroxidase-like activity.

The Ce4+↔Ce3+ redox switch is at the basis of an all-inorganic catalytic cycle that is capable of mimicking the activity of several natural redox enzymes. The efficiency of these artificial enzymes (nanozymes) strongly depends on the Ce4+/Ce3+ ratio. By capitalizing on the results obtained on oxide/oxide model systems, we implemented a simple and effective procedure to obtain conformal TiO2@CeOx core-shell nanoparticles whose thickness is controlled with single-layer precision.

Nurses' autonomy in end-of-life situations in intensive care units.

Background: The intensive care unit environment focuses on interventions and support therapies that prolong life. The exercise by nurses of their autonomy impacts on perception of the role they assume in the multidisciplinary team and on their function in the intensive care unit context. There is much international research relating to nurses' involvement in end-of-life situations; however, there is a paucity of research in this area in Brazil.

The interaction of oxygen with the surface of CeO₂-TiO₂ mixed systems: an example of fully reversible surface-to-molecule electron transfer.

The interaction of oxygen with the surface of CeO2-TiO2 mixed oxides prepared via sol-gel was investigated by means of electron paramagnetic resonance (EPR). Upon admission of molecular oxygen onto the surface of the as prepared materials (which underwent final oxidative calcination) the formation of superoxide O2(-) ions is observed without the need for preliminary annealing in a vacuum and consequent oxygen depletion. The superoxide species is symmetrically adsorbed ("side-on" structure) on the top of a Ce(4+) ion.

Charge trapping in TiO2 polymorphs as seen by Electron Paramagnetic Resonance spectroscopy.

Electron Paramagnetic Resonance (EPR) techniques have been employed to investigate charge carrier trapping in the two main TiO2 polymorphs, anatase and rutile, with particular attention to the features of electron trapping sites (formally Ti(3+) ions). The classic CW-EPR technique in this case provides signals based on the g tensor only. Nevertheless a systematic analysis of the signals obtained in the various cases (anatase and rutile, surface and bulk centers, regular and defective sites) has been performed providing useful guidelines on a field affected by some confusion.

Emergence of extended-spectrum β-lactamase producing Enterobacter spp. in patients with bacteremia in a tertiary hospital in southern Brazil.

Background: Extended-spectrum β-lactamases (ESBLs) are increasingly prevalent in Enterobacter spp., posing a challenge to the treatment of infections caused by this microorganism. The purpose of this retrospective study was to evaluate the prevalence, risk factors, and clinical outcomes of inpatients with bacteremia caused by ESBL and non ESBL-producing Enterobacter spp.

HYSCORE and Davies ENDOR study of irradiated ultra high molecular weight polyethylene.

Ultra high molecular weight polyethylene (UHMWPE) has been studied with different magnetic resonance techniques to elicit information on the nature and the location of radicals generated during high energy irradiation. Field swept electron paramagnetic resonance, pulsed Davies electron nuclear double resonance and hyperfine sublevel correlation spectroscopic measurements allowed extracting for the first time the full (1) H hyperfine coupling tensors of the most abundant radical, i.e.

Electron beam radiation effects on UHMWPE: an EPR study.

Electron paramagnetic resonance (EPR) technique has been employed to detect and characterise a series of different radical species generated in ultra-high molecular weight polyethylene (UHMWPE) via electron beam irradiation. Three different radical species have been found and assigned on the basis of their EPR spectra and of the related computer simulations. A secondary alkyl species, the prevalent one, is present immediately after irradiation, an allyl species appears only 24 h after irradiation when the alkyl species disappears.