Chemical effect of hydrodynamic cavitation: Simulation and experimental comparison

The chemical effect of hydrodynamic cavitation (HC) in a Venturi reactor from both the theoretical and the experimental point of view is dealt. A mathematical model is presented to simulate the global production of hydroxyl radicals; it is based on a set of ordinary differential equations that account for the hydrodynamics, mass diffusion, heat exchange, and chemical reactions inside the bubbles. Experimentally, the degradation of p‐nitrophenol (initial concentration 0.15 g dm^?3) has been conducted in a lab scale Venturi reactor at inlet pressure ranging from 0.2 to 0.6 MPa and has been used to estimate the hydroxyl radical production. The optimum configuration, suggested by numerical simulations, has been experimentally confirmed. Thanks to the empirical validation, this novel modeling approach can be considered as a theoretical tool to identify the best configuration of HC operating parameters. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2566–2572, 2014     

Determination of Benzalkonium Homologues and Didecyldimethylammonium in Powdered and Liquid Milk for Infants by Hydrophilic Interaction Liquid Chromatography–Mass Spectrometry

In this study, a hydrophilic interaction liquid chromatography–mass spectrometry (HILIC-MS/MS) method for the determination of benzalkonium (BAC) homologues and didecyldimethylammonium (DDAC) was developed. A satisfactory chromatographic separation of BAC homologues and DDAC was achieved using, as mobile phase, acetonitrile–aqueous 50 mM ammonium formate (pH 3.2) (93?+?7 v/v) at 0.3 mL min^?1. The elution order of BAC homologues was from benzyldimethylhexadecylammonium chloride (C₁₆-BAC) to benzyldimethyldecylammonium chloride (C₁₀-BAC), the exact opposite with respect to separation using reversed liquid chromatography. The instrumental method was successfully applied to powdered and liquid milk for infants (about 50 samples). From powdered milk samples, BAC and DDAC were extracted using 5 % formic acid in methanol for 60 min at 60 °C in an ultrasonic bath; after dilution with water and 5 % NH₄OH solution, a purification step using a weak cationic exchange column was performed. Satisfactory limit of detections (LODs) were achieved, below 1.0 μg kg^?1 and 0.05 μg L^?1 for powdered and liquid milk for infants, respectively. No sample was free of BAC homologues and DDAC, and in one powdered milk sample, the contamination level exceeded 500 μg kg^?1, the maximum level recommended by the Standing Committee on the Food Chain and Animal Health for food and feed.     

Discovery of Tyrosine Kinase Inhibitors by Docking into an Inactive Kinase Conformation Generated by Molecular Dynamics

Several small molecules that bind to the inactive DFG‐out conformation of tyrosine kinases (called type II inhibitors) have shown a good selectivity profile over other kinase targets. To obtain a set of DFG‐out structures, we performed an explicit solvent molecular dynamics (MD) simulation of the complex of the catalytic domain of a tyrosine kinase receptor, ephrin type‐A receptor 3 (EphA3), and a manually docked type II inhibitor. Automatic docking of four previously reported type II inhibitors was used to select a single snapshot from the MD trajectory for virtual screening. High‐throughput docking of a pharmacophore‐tailored library of 175 000 molecules resulted in about 4 million poses, which were further filtered by van der Waals efficiency and ranked according to a force‐field‐based energy function. Notably, around 20 % of the compounds with predicted binding energy smaller than ?10 kcal mol^?1 are known type II inhibitors. Moreover, a series of 5‐(piperazine‐1‐yl)isoquinoline derivatives was identified as a novel class of low‐micromolar inhibitors of EphA3 and unphosphorylated Abelson tyrosine kinase (Abl1). The in silico predicted binding mode of the new inhibitors suggested a similar affinity to the gatekeeper mutant T315I of Abl1, which was verified in vitro by using a competition binding assay. Additional evidence for the type II binding mode was obtained by two 300 ns MD simulations of the complex between N‐(3‐chloro‐4‐(difluoromethoxy)phenyl)‐2‐(4‐(8‐nitroisoquinolin‐5‐yl)piperazin‐1‐yl)acetamide and EphA3.     

Characterization of He embrittlement of a 9Cr–1Mo steel using local approach of brittle fracture

Ferritic-martensitic steels are prime candidate materials for future reactors. We present here the results of a study on the effects of helium implantation on the fracture behavior of 9Cr (T91) martensitic steels. Three-points static bending tests were performed at room temperature on implanted specimens and at −170 °C on un-implanted material. All these tests led to brittle fracture. Based on a mechanical analysis of the tests results using Finite Element calculations, we have proposed that the mechanism of brittle fracture is controlled by a double criterion depending on implantation temperature and helium content. Furthermore, by applying the Beremin model, the toughness of helium implanted steel has been evaluated.     

High-Fat Diet Impairs Mouse Median Eminence: A Study by Transmission and Scanning Electron Microscopy Coupled with Raman Spectroscopy

Hypothalamic dysfunction is an initial event following diet-induced obesity, primarily involving areas regulating energy balance such as arcuate nucleus (Arc) and median eminence (ME). To gain insights into the early hypothalamic diet-induced alterations, adult CD1 mice fed a high-fat diet (HFD) for 6 weeks were studied and compared with normo-fed controls. Transmission and scanning electron microscopy and histological staining were employed for morphological studies of the ME, while Raman spectroscopy was applied for the biochemical analysis of the Arc-ME complex. In HFD mice, ME β2-tanycytes, glial cells dedicated to blood-liquor crosstalk, exhibited remarkable ultrastructural anomalies, including altered alignment, reduced junctions, degenerating organelles, and higher content of lipid droplets, lysosomes, and autophagosomes. Degenerating tanycytes also displayed an electron transparent cytoplasm filled with numerous vesicles, and they were surrounded by dilated extracellular spaces extending up to the subependymal layer. Consistently, Raman spectroscopy analysis of the Arc-ME complex revealed higher glycogen, collagen, and lipid bands in HFD mice compared with controls, and there was also a higher band corresponding to the cyanide group in the former compared to the last. Collectively, these data show that ME β₂-tanycytes exhibit early structural and chemical alterations due to HFD and reveal for the first-time hypothalamic cyanide presence following high dietary lipids consumption, which is a novel aspect with potential implications in the field of obesity.     

Myocardial blood flow quantification from MRI by deconvolution using an exponential approximation basis

We have evaluated the use of deconvolution using an exponential approximation basis for the quantification of myocardial blood flow from perfusion cardiovascular magnetic resonance. Our experiments, based on simulated signal intensity curves, phantom acquisitions, and clinical image data, indicate that exponential deconvolution allows for accurate quantification of myocardial blood flow. Together with automated respiratory motion correction myocardial contour delineation, the exponential deconvolution enables efficient and reproducible quantification of myocardial blood flow in clinical routine.     

Residues of the quinone outside inhibitor fungicide trifloxystrobin after postharvest dip treatments to control Penicillium spp. on citrus fruit

The effectiveness of postharvest dip treatment with trifloxystrobin (TFX) or imazalil (IMZ) was compared for controlling green and blue mold (caused by Penicillium digitatum and Penicillium italicum, respectively) of citrus fruit. Residues retained by fruit were determined as a function of treatment time, dip temperature, and storage conditions. Trials on 'Avana apireno' mandarin oranges artificially inoculated with P. digitatum or P. italicum revealed that treatments with 200 to 600 mg/liter active ingredient TFX at 20 degrees C were less effective than 100 mg/liter TFX at 500C for controlling P. digitatum but equally effective for controlling P. italicum. IMZ treatments with 200 mg/liter IMZ at 20 degrees C or 25 mg/liter IMZ at 50 degrees C resulted in more than 98% reduction of P. digitatum and ca. 93% reduction of P. italicum compared with untreated fruit. Total suppression of pathogens was achieved when higher IMZ doses were applied. Studies on artificially wounded lemons, oranges, clementines, and mandarins revealed that treatment with 100 mg/liter TFX at 50 degrees C effectively controlled decay development (mainly due to P. digitatum) after 7 days of storage at 20 degrees C. These results were confirmed on nonwounded oranges of cv. Tarocco and on grapefruits of cvs. Marsh Seedless and Star Ruby during 3 weeks of simulated quarantine at 1 degrees C, storage (5 weeks at 8 degrees C for oranges and 8 weeks at 11degrees C for grapefruits), and an additional 1 week of simulated marketing conditions at 20 degrees C. IMZ at 50 degrees C was highly effective for controlling decay during storage and the simulated marketing period. TFX treatment at 50 degrees C was as effective as IMZ for controlling decay in most samples. After treatment with 100 mg/liter TFX at 20 degrees C, fungicide residues in 'Tarocco' oranges doubled from 0.15 mg/kg to 0.30 mg/kg when dip time increased from 0.5 to 3 min, whereas when treatments were performed at 50 degrees C TFX residues were not related to dipping time. Residues of TFX were significantly correlated with dip temperature. A 3-min dip treatment at 50 degrees C resulted in a deposition of TFX that was approximately twofold higher than that obtained when treatments were carried out at 20 degrees C.     

Oak forest exploitation and black-locust invasion caused severe shifts in epiphytic lichen communities in Northern Italy

In the last two centuries, native European oak forests have undergone a dramatic decline related to increasing human pressure for agriculture and urbanization. Oak forests were either completely eradicated and transformed into agricultural landscapes or replaced by second-growth formations. Intensive forest management and the replacement of native forests with production forests or arable lands are recognized amongst the main threats to many lichens in Europe. In this study, we used historical information on the epiphytic lichen biota which was hosted in a native oak-dominated forest of Northern Italy to identify shifts of lichen communities due to the changes in land use which occurred during the last two centuries. We also compared the epiphytic lichen communities inhabiting remnant oak forests with those found in the habitats that have replaced native forests: black-locust forests and agrarian landscapes. Almost all the species sampled during the 19th century are now extinct. The loss of native habitat and the subsequent invasion by black locust were probably the most influential factors which affected the composition of lichen communities, causing the local extinction of most of the species historically recorded. Despite the fact that oak remnants host only a few species which were historically recorded, and that they currently are the lichen poorest habitat in the study region, they host lichen assemblages differing from those of black-locust forests and agrarian stands. In these habitats lichen assemblages are mainly composed of species adapted to well-lit, dry conditions and tolerating air pollution and eutrophication. This pattern is likely to be common also in other lowland and hilly regions throughout Northern Italy where oak forests are targeted among the habitats of conservation concern at the European level. For this reason, a national strategy for biodiversity conservation and monitoring of lowlands forests should provide the framework for local restoration projects.