Highly bright and photostable cyanine dye-doped silica nanoparticles for optical imaging: Photophysical characterization and cell tests

Spherical silica nanoparticles containing fluorescent trimethine indocyanine dyes (λ_abs = 547 nm, λ_em = 570 nm) were prepared using a water-in-oil microemulsion method. The nanoparticles were of 50 nm diameter and were almost monodispersed in aqueous solution at pH 5.5. Entrapment of dye molecules in the silica matrix stabilised photoemission over several hours of continuous irradiation. The photoemission intensity of the indocyanine was increased 13-fold over that recorded in solution. As each nanoparticle contained 110 dye molecules, the photoemission brightness of each particle was enhanced by three orders of magnitude. The fluorescent nanoparticles have been tested as imaging tools in in vitro tests. As an example of non-macrophagic cells, a highly differentiated neuronal cell line (GT1-7) was used and the results showed that the prepared nanoparticles can be incorporated into these cells with no apparent toxicity for up to three days.     

Microwave-assisted polyol synthesis of sub-micrometer Y2O3 and Yb-Y2O3 particles for laser source application

Sub-micrometer powder (100–150 nm diameter) of Yb-doped yttrium oxide was obtained, for the first time, by microwave-assisted polyol (diethylene glycol, DEG) method. This method is based on fast and homogeneous increase of temperature, due to the microwave heating, and on addition of the hydrolysing agent (water) at high temperature. This promotes a fast nucleation followed by a controlled growth of nuclei. Different procedures were used to process the as-synthesized powders. In some cases washing by ultrapure water was used to dissolve nitrate and DEG by-products, this treatment allowed the use of a lower calcination temperature (150–200 °C less) to obtain the crystalline phase. Analysis of the calcined powder showed different levels of structures: from nanocrystal (10–15 nm), to primary particles (100–150 nm), to micrometer soft aggregates (2–4 μm). The microwave-assisted polyol method resulted an easy way to dope yttria with the desired amount of Yb³⁺. This work was carried out in order to prepare particles to be used as rare-earth doped Y₂O₃ and YAG polycrystalline transparent ceramic for laser source applications.     

Rapid FTIR determination of water,phenolics and antioxidant activity of olive oil

A rapid Fourier transformed infrared (FTIR) attenuated total reflectance (ATR) spectroscopic method was applied to the determination of water content (WC), total phenol amount (TP) and antioxidant activity (ABTS ^{. +}) of virgin olive oils (VOO) and olive oils. Calibration models were constructed using partial least squares regression. Oil samples with WC ranging from 289 to 1402 mg water/kg oil, with TP from 46 to 877 mg gallic acid/kg oil and with ABTS ^{. +} from 0 to 5.7 mmol Trolox/kg oil were considered for chemometric analysis. Better results were obtained when selecting suitable spectral ranges; in particular, from 2260 to 1008 cm^?1 for WC, from 3610 to 816 cm^?1 for TP and from 3707 to 1105 cm^?1 for ABTS ^{. +}. Satisfactory LOD values by the FTIR‐chemometric methods were achieved: 9.4 (mg/kg oil) for WC; 12.5 (mg gallic acid/kg oil) for TP, and 0.76 (mmol Trolox/kg oil) for ABTS ^{. +}. The evaluation of the applicability of these analytical approaches was tested by use of validation sample sets (n = 16 for WC, n = 11 for TP and n = 14 for ABTS) with nearly quantitative recovery rates (99–114%). The FTIR–ATR method provided results that were comparable to conventional procedures. Practical applications : The presented method is based on ATR–FTIR in combination with multivariate calibration methodologies and permits a simultaneous evaluation of important quality parameters of VOO (WC, TP and ABTS ^{. +}). This approach represents an easy and convenient means for monitoring olive oil quality with the advantage of ease of operation, speed, no sample pretreatment and no consumption of solvents. The data obtained with this method are comparable to those obtained using the official reference method. Therefore, the technique is highly plausible as an alternative to the standard procedure for routine analysis or control at‐line of production processes.     

Cigarette Smoke Affects ABCAl Expression via Liver X Receptor Nuclear Translocation in Human Keratinocytes

Cutaneous tissue is the first barrier against outdoor insults. The outer most layer of the skin, the stratum corneum (SC), is formed by corneocytes embedded in a lipid matrix (cholesterol, ceramide and fatty acids). Therefore, the regulation of lipids and, in particular, of cholesterol homeostasis in the skin is of great importance. ABCA1 is a membrane transporter responsible for cholesterol efflux and plays a key role in maintaining cellular cholesterol levels. Among the many factors that have been associated with skin diseases, the environmental stressor cigarette smoke has been recently studied. In the present study, we demonstrate that ABCA1 expression in human cells (HaCaT) was increased (both mRNA and protein levels) after CS exposure. This effect was mediated by the inhibition of NFkB (aldehydes adducts formation) that allows the translocation of liver X receptor (LXR). These findings suggest that passive smoking may play a role in skin cholesterol levels and thus affect cutaneous tissues functions.     

High-pressure processing of Gorgonzola cheese: influence on Listeria monocytogenes inactivation and on sensory characteristics

The presence of Listeria monocytogenes on the rind of Gorgonzola cheese is difficult to avoid. This contamination can easily occur as a consequence of handling during ripening. The aims of this study were to determine the efficiency of high-pressure processing (HPP) for inactivation of L. monocytogenes on cheese rind and to evaluate the influence of HPP treatments on sensory characteristics. Gorgonzola cheese rinds, after removal, were inoculated (about 7.0 log CFU/g) with L. monocytogenes strains previously isolated from other Gorgonzola cheeses. The inoculated cheese rinds were processed with an HPP apparatus under conditions of pressure and time ranging from 400 to 700 MPa for 1 to 15 min. Pressures higher than 600 MPa for 10 min or 700 MPa for 5 min reduced L. monocytogenes more than 99%. A reduction higher than 99.999% was achieved pressurizing cheese rinds at 700 MPa for 15 min. Lower pressure or time treatments were less effective and varied in effectiveness with the cheese sample. Changes in sensory properties possibly induced by the HPP were evaluated on four different Gorgonzola cheeses. A panel of 18 members judged the treated and untreated cheeses in a triangle test. Only one of the four pressurized cheeses was evaluated as different from the untreated sample. HPP was effective in the reduction of L. monocytogenes on Gorgonzola cheese rinds without significantly changing its sensory properties. High-pressure technology is a useful tool to improve the safety of this type of cheese.     

Determination of Lutein from Fruit and Vegetables Through an Alkaline Hydrolysis Extraction Method and HPLC Analysis

A simple and rapid analytical method for the determination of lutein content, successfully used for cereal matrices, was evaluated in fruit and vegetables. The method involved the determination of lutein after an alkaline hydrolysis of the sample matrix, followed by extraction with solvents and analysis by normal phase HPLC. The optimized method was simple, precise, and accurate and it was characterized by few steps that could prevent loss of lutein and its degradation. The optimized method was used to evaluate the lutein amounts in several fruit and vegetables. Rich sources of lutein were confirmed to be green vegetables such as parsley, spinach, chicory, chard, broccoli, courgette, and peas, even if in a range of variability. Taking into account the suggested reference values these vegetables can be stated as good sources of lutein.     

Coarse‐grained models for frontal photopolymerization with evolving conversion profile

We introduce a series of ‘minimal’ models to describe a common light‐driven directional solidification process, known as frontal photopolymerization (FPP ), focusing on experimental observables: the solidification kinetics, light attenuation and spatiotemporal monomer‐to‐polymer conversion. Specifically, we focus on FPP propagation that yields conversion profiles that are not invariant with time, and which cannot be simply described by the presence of mass or heat diffusion. The models are assessed against experimental data for the photopolymerization of a model trimethacrylate system. We find that the simplest model, comprising a single equation of motion for the conversion fraction ? and a generalized Beer–Lambert law, can only describe the experimental data by assuming an unphysical variation in optical absorption. Introducing a ? ‐dependent reaction constant K _eff is found to require a time dependence, regardless of the functional form in ? . We conclude by introducing a ‘minimal’ chemical model, which is based on a simple three‐step reaction scheme involving the spatiotemporal evolution of the photoinitiator fraction, relative fraction of radicals and monomer conversion fraction, that is able to capture the experimental data with a small number of parameters and under reasonable FPP assumptions. Our framework provides important predictive ability for ubiquitous solidification and patterning processes, including three‐dimensional printing, via photopolymerization. © 2017 Society of Chemical Industry     

Molecular Pathogenesis of NASH

Nonalcoholic steatohepatitis (NASH) is the main cause of chronic liver disease in the Western world and a major health problem, owing to its close association with obesity, diabetes, and the metabolic syndrome. NASH progression results from numerous events originating within the liver, as well as from signals derived from the adipose tissue and the gastrointestinal tract. In a fraction of NASH patients, disease may progress, eventually leading to advanced fibrosis, cirrhosis and hepatocellular carcinoma. Understanding the mechanisms leading to NASH and its evolution to cirrhosis is critical to identifying effective approaches for the treatment of this condition. In this review, we focus on some of the most recent data reported on the pathogenesis of NASH and its fibrogenic progression, highlighting potential targets for treatment or identification of biomarkers of disease progression.