Photodegradation of fluoroquinolones in surface water and antimicrobial activity of the photoproducts

The widespread presence of fluoroquinolone antibiotics (FQs) in natural ecosystems is a health hazard for humans and other living organisms. The role of sunlight in degrading FQs present in environmental waters has been studied. In particular, the photodegradation of four largely employed FQs, viz. Ciprofloxacin (CIP), Danofloxacin (DAN), Levofloxacin (LEV) and Moxifloxacin (MOX) has been studied in not tampered river water. Degradation rates have been investigated at ppb levels (20-50 μg L⁻¹) under solar light, and the results have been commented critically. The products distribution has been studied by HPLC-ESI-MS/MS analysis and structures have been attributed on the basis of their mass fragmentation spectra.Importantly from the environmental point of view, the (potentially toxic) FQ nucleus remained intact over the early stages of the degradation. Indeed, the photoproducts were proved to possess residual antibacterial activity, as shown from in vitro antibacterial activity tests against different well characterized human and environmental bacterial strains, carried out on the above FQs, as well as for Enrofloxacin (ENR) and Marbofloxacin (MAR).     

Niemann-Pick C2 Protein Expression Regulates Lithogenic Diet-Induced Gallstone Formation and Dietary Cholesterol Metabolism in Mice

Niemann-Pick C2 protein (NPC2) is a lysosomal soluble protein that is highly expressed in the liver; it binds to cholesterol and is involved in intracellular cholesterol trafficking, allowing the exit of lysosomal cholesterol obtained via the lipoprotein endocytic pathway. Thus, this protein may play an important role in controlling hepatic cholesterol transport and metabolism. The aim of this work was to study the relevance of NPC2 protein expression in hepatic cholesterol metabolism, biliary lipid secretion and gallstone formation by comparing NPC2 hypomorph [NPC2 (h/h)] and wild-type mice fed control, 2% cholesterol, and lithogenic diets. NPC2 (h/h) mice exhibited resistance to a diet-induced increase in plasma cholesterol levels. When consuming the chow diet, we observed increased biliary cholesterol and phospholipid secretions in NPC2 (h/h) mice. When fed the 2% cholesterol diet, NPC2 (h/h) mice exhibited low and high gallbladder bile cholesterol and phospholipid concentrations, respectively. NPC2 (h/h) mice fed with the lithogenic diet showed reduced biliary cholesterol secretion, gallbladder bile cholesterol saturation, and cholesterol crystal and gallstone formation. This work indicates that hepatic NPC2 expression is an important factor in the regulation of diet-derived cholesterol metabolism and disposal as well as in diet-induced cholesterol gallstone formation in mice.     

A New Family of Conformationally Constrained Bicyclic Diarylprolinol Silyl Ethers as Organocatalysts

Simple chemical manipulations of trans‐4‐L ‐hydroxy proline allow the access to a new family of bicyclic silyl ether organocatalysts that display some remarkable features. Apart from being extremely stable to hydrolytic conditions and possessing excellent catalytic performances, the rigidity of the bicyclic structure imposes a synclinal endo disposition of the bulky substituents with respect to the pyrrolidine ring, opposed to the more stable synclinal exo conformations of Jørgensen–Hayashi catalysts.     

Carbon nanohorn-based nanofluids: characterization of the spectral scattering albedo

The full characterization of the optical properties of nanofluids consisting of single-wall carbon nanohorns of different morphologies in aqueous suspensions is carried out using a novel spectrophotometric technique. Information on the nanofluid scattering and absorption spectral characteristics is obtained by analyzing the data within the single scattering theory and validating the method by comparison with previous monochromatic measurements performed with a different technique. The high absorption coefficient measured joint to the very low scattering albedo opens promising application perspectives for single-wall carbon nanohorn-based fluid or solid suspensions. The proposed approximate approach can be extended also to other low-scattering turbid media.     

European research in the field of production technology and manufacturing systems: an exploratory analysis through publications and patents

This paper develops a structured comparison among a sample of European researchers in the field of production technology and manufacturing systems on the basis of two research outputs: scientific publications and patents. Researchers are evaluated and compared by a variegated set of indicators concerning (1) the output of individual researchers and (2) that of groups of researchers from the same country. Whilst not claiming to be exhaustive, the results of this preliminary study provide a rough indication of the publishing and patenting activity of European researchers in the field of interest, identifying (dis)similarities between different countries with regard to their inclination to publishing and patenting. Of particular interest is a proposal for aggregating analysis results by means of maps based on publication and patent indicators. A large amount of empirical data are presented and discussed.     

Ethyl silicate for surface treatment of concrete - Part II: Characteristics and performance

In this study, several aspects of the surface treatment of concrete with ethyl silicate were investigated. After the treatment, two different types of concrete (w/c 0.45 and 0.65) showed a dramatic decrease in capillary suction, chloride diffusion coefficient and carbonation depth. A penetration depth into the concrete of about 3-5 mm was assessed. Microstructural investigations showed evidence of a chemical interaction of the amorphous silica gel within the concrete forming calcium silica gel and a selective distribution of silica gel, which was mainly deposited in the small pores. In addition, the brightness and colour changes of the concrete surfaces after the treatment were analyzed quantitatively, finding limited differences, further decreasing over time. This last aspect is relevant for architectural applications of concrete, for example façades of residential buildings, where the architects may be interested in using the texture of concrete but are concerned by possible colour changes related to surface treatments application.     

Hydrolysis-condensation kinetics of 3-(2-amino-ethylamino)propyl-trimethoxysilane

The kinetics of the hydrolysis and self-condensation reactions of 3-(2-amino-ethylamino)propyl-trimethoxysilane (DAMS) were investigated by in situ²⁹Si NMR spectroscopy using pure water and an alcoholic (80:20 w/w ethanol/water) solvent mixture as reaction media. In both media, the reactivity of the silane was strongly influenced by the pH of the medium during the initial stage of the reaction. The silanols produced by hydrolysis in water were much more stable than those produced in the alcoholic solvent mixture, the latter of which were susceptible to self-condensation, yielding siloxane bridges. The active silanol reactivity (SR), which is a simple parameter that reflects the silanol content in the solution as a function of the reaction time, was proposed for evaluating the reactivity of a solution of DAMS. SR was maintained at a good level (high silanol group concentration) when pure water was used as the reaction medium. The pH of the reaction appears to be the predominant parameter for determining the SR during the first 2 h, regardless of the reaction solvent.     

Room-temperature metastability of multilayer graphene oxide films

Graphene oxide potentially has multiple applications. The chemistry of graphene oxide and its response to external stimuli such as temperature and light are not well understood and only approximately controlled. This understanding is crucial to enable future applications of this material. Here, a combined experimental and density functional theory study shows that multilayer graphene oxide produced by oxidizing epitaxial graphene through the Hummers method is a metastable material whose structure and chemistry evolve at room temperature with a characteristic relaxation time of about one month. At the quasi-equilibrium, graphene oxide reaches a nearly stable reduced O/C ratio, and exhibits a structure deprived of epoxide groups and enriched in hydroxyl groups. Our calculations show that the structural and chemical changes are driven by the availability of hydrogen in the oxidized graphitic sheets, which favours the reduction of epoxide groups and the formation of water molecules.     

Matrix transformation in fiber-added extruded products: Impact of different hydration regimens on texture, microstructure and digestibility

The objective of this work was to study the effect of three hydration regimens on the extent of matrix transformation, texture, microstructure and digestibility of a corn-based extruded product blended with apple pomace. Blends containing 0%, 17%, 22%, and 28% pomace were hydrated to 17.2% by adding water either into the preconditioner (P), the extruder (E) or dividing half in each (PE). Increasing the opportunity for hydration (P > PE > E) promoted more complete starch gelatinization at all pomace levels. Apple pomace promoted milder extrusion conditions, resulting in less starch gelatinization and solubilization, poor expansion and reduced starch digestibility. Digestible starch was inversely correlated to cell wall thickness/cell size ratio (r = 0.91), which increased with pomace addition. Thus, pomace decreased digestibility by promoting changes in structure and gelatinization. Delayed water addition (E) promoted broader cell size and cell wall thickness distributions, attributed to poor mixing and hydration. Therefore, water incorporation (not just total content) is a key factor in defining extrudate microstructure, texture and digestibility patterns.     

Immunoassay based on monoclonal antibody for aflatoxin detection in poultry feed

An indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) based on an anti-aflatoxin B₁ monoclonal antibody was standardised and validated for aflatoxin screening in poultry feed samples and its performance was compared to high-performance liquid chromatography (HPLC). The ic-ELISA showed good linearity (r² = 0.994) and detection limits of 1.25 ng g⁻¹ for broiler feed and 1.41 ng g⁻¹ for laying hen feed. Mean aflatoxin recovery rates by ic-ELISA were 102% (laying hen feed) and 98% (broiler feed). Aflatoxins were detected in 88.2% of the 34 broiler feed samples by ic-ELISA and HPLC at means of 10.48 ng g⁻¹ and 8.41 ng g⁻¹, respectively, while 92% of laying hen feed samples (n = 36) showed aflatoxin contamination at means of 20.83 and 19.75 ng g⁻¹. The standardised ic-ELISA showed reliability and a high correlation with HPLC of 0.97 (broiler feed) and 0.98 (laying hen feed) indicating its potential for aflatoxin screening in poultry feed samples.