Nano Design of Alumina Supported Monometallic Catalysts: A Promising Way to Improve the Selective Hydrogenation of Poly-Unsaturated Hydrocarbons

In the field of catalysis by metals, a new insight for the nanodesign of supported heterogeneous catalysts is the tailoring of metallic nanoparticles. In this work, well-faceted monometallic nanoparticles (Pd, Pt, Ni) exposing mostly the {111} crystallographic facet are obtained in aqueous solution and are deposited on an alumina support. The involved mechanisms of nanoparticles formation are determined and are evidenced to be different as a function of the nature of the metal. In the case of palladium the mechanism consists in an oriented attachment of palladium nanoparticles leading to the energetically most favourable stacking of nanoparticles, at the origin of the early differentiation of the nanoparticles shapes and of the formation of the well-faceted palladium nanoparticles. In the case of platinum, the mechanism seems to be a combination of aggregation of already reduced nuclei and direct reduction depending on the experimental conditions. In the case of the less reductible metal, nickel, well-faceted nanoparticles are not obtained during the synthesis and only a thermal activation under hydrogen can engender their formation. The impact of the {111} crystallographic facet for platinum and nickel is very important and induces a drastic increase of selectivity towards olefins formation with a selectivity close to the one of a palladium catalyst which is the most selective metal for the selective hydrogenation of poly-unsaturated hydrocarbons.     

Calculations of the binding of hydrogen to fixed interstitial impurities in nickel

We have calculated the binding energy of hydrogen to inert, fixed interstitial impurity atoms He, Ne, Ar, Kr, and Xe and also the chemically active impurities C, O, and N in Ni using local density functional theory including lattice relaxation.     

A LiDAR survey of Stromboli volcano (Italy): Digital elevation model-based geomorphology and intensity analysis

LiDAR (Light Detection and Ranging) is a novel and very useful active remote sensing system which can be used to directly identify geomorphological features as well as the properties of materials on the ground surface. In this work, LiDAR data were applied to the study of the Stromboli volcano in Italy. LiDAR data points, collected during a survey in October 2005, were used to generate a Digital Elevation Model (DEM) and a calibrated intensity map of the ground surface. The DEM, derived maps and topographic cross-sections were used to complete a geomorphological analysis of Stromboli, which led to the identification of four main geomorphological domains linked to major volcanic cycles. Moreover, we investigated and documented the potential of LiDAR intensity data for distinguishing and characterizing different volcanic products, such as fallout deposits, epiclastic sediments and lava flows.     

Mixed secretory and obstructive azoospermia. Transseptal vasovasostomy by vas deferens transposition: a case report and review of the literature

PURPOSE: To report on unusual imaging presentations in renal transitional cell carcinoma (TCC). MATERIAL AND METHODS: Imaging studies of 140 cases of pathologically proven renal TCC were retrospectively studied with the focus on unusual presentations. RESULTS: Unusual imaging manifestations were found in 20 cases (14.3%). These findings were classified into 5 categories: perirenal abscesses or perirenal hematomas in 6 cases; parenchymal masses in 5; undue thickening of the hydronephrotic wall in 4; "tuberculoid" pyelograms in 3; and tumors with massive necrosis in 2. CONCLUSION: Deceptive imaging presentations may occur in renal TCC. Recognition of these presentations may help to prevent delay in diagnosis.     

Effect of plasma fluctuations on in-flight particle parameters

The influence of arc root fluctuations in direct current (DC) plasma spraying on the physical state of the particle jet is investigated by correlating individual in-flight particle temperature and velocity measurements with the instantaneous voltage difference between the electrodes. In-flight diagnostics with the DPV-2000 sensing device involve two-color pyrometry and time-of-flight technique for the determination of temperature and velocity. Synchronization of particle diagnostics with the torch voltage fluctuations are performed using an electronic circuit that generates a pulse when the voltage reaches some specific level; this pulse, which can be shifted by an arbitrary period of time, is used to trigger the acquisition of the pyrometric signals. Contrary to predictions obtained by numerical modeling, time-dependent variations in particle temperature and velocity due to power fluctuations induced by the arc movement can be very large. Periodic variations of the mean particle temperature and velocity, up to ΔT=600 °C and Δv=200 m/s, are recorded in the middle of the particle jet during a voltage cycle. To our knowledge, this is the first time that large time-dependent effects of the arc root fluctuations on the particle state (temperature and velocity) are experimentally demonstrated. Moreover, large fluctuations in the number of detected particles are observed throughout a voltage cycle; very few particles are detected during parts of the cycle. The existence of quiet periods suggests that particles injected at some specific moments in the plasma are not heated sufficiently to be detected.     

Lachancea thermotolerans as an alternative yeast for the production of beer

The ability of Lachancea thermotolerans strains to ferment brewer's wort has been investigated. Initial fermentations with three L. thermotolerans strains compared the use of maltose and maltotriose, as well as production of glycerol and lactic acid and pH evolution over the course of the fermentation. The most promising strain was subsequently tested for additional traits important for beer production, including pitching rate, generational capacity, foam stability, hop tolerance, vicinal diketone production, oxygen requirement and flocculation. These tests suggest that L. thermotolerans may be a good choice for producing sour beers in a single fermentation step without the use of lactic acid bacteria. Copyright © 2016 The Institute of Brewing & Distilling     

New Bitopic Ligands for the Group Actinide Separation by Solvent Extraction

Abstract

The synthesis and evaluation of solvent extraction performance of N,N,N′,N′-tetraalkyl-6,6″-(2,2′:6′,2″-terpyridine)diamides and N,N′-diethyl-N,N′-diphenyl-6,6″-(2,2′:6′,2″-terpyridine)diamide are reported here. These new bitopic ligands were found to extract actinides in different oxidation states (U(VI), Np(V and VI), Pu(IV), Am(III), and Cm(III)) from 3 M nitric acid. The presence of three soft nitrogen donors led to the selective extraction of actinides(III) over lanthanides(III) (Ce, Eu) and the presence of two amide functional groups grafted to the terpyridine unit allowed the extraction to occur from a highly acidic medium by minimizing the basicity of the ligand. Ligands bearing long alkyl chains (C4 and C8) or phenyl groups showed increased performances in a polar diluent like nitrobenzene.     

The Biotechnology of Wine Yeast

The production of wine from grapes is one of the world's oldest biotechnological processes. The alcoholic fermentation, the conversion of grape sugars to ethanol, is conducted by yeast of the genus Saccharomyces. In addition to wide-ranging roles in beverage and food processing, Saccharomyces is also a premier research model system because of its genetic tractability. Its genome has been sequenced, and an extensive array of molecular technologies has been developed for the genetic manipulation of this organism. In spite of the availability of these molecular tools, genetically engineered yeast strains are not yet in use in the commercial wine industry. Anxiety over consumer acceptance is one reason genetically modified strains are not employed, but there are other concerns as well. Wine production is unique in many respects. The wine production process is not conducted under sterile conditions, and any modified organism has the potential to become an enduring resident of the winery flora. Further, wine production is both science and art. There is concern that many of the proposed genetic modifications of yeast are designed to correct processing errors or incompetence of the winemaker rather than being useful tools to enhance the artistry of wine making. In spite of these concerns, the efficacy of genetic modification of wine yeast has been demonstrated.     

Polarization control of a Yb:YAG ceramic microchip laser by constructive-interference resonant grating mirror

A laser output coupler comprising a resonant grating submirror monolithically associated with a multilayer submirror according to a constructive interference scheme polarizes the emission of a rare-earth-doped YAG-ceramic microchip laser over its full bandwidth. The design and fabrication of the resonant grating mirror are described. A polarization contrast ratio of more than 1000 was obtained with single transverse mode operation.     

Preoperative localization of parathyroid lesions in hyperparathyroidism: relationship between technetium-99m-MIBI uptake and oxyphil cell content

The aim of this study was to assess the relationship between parathyroid oxyphil cell content and early or late phases of uptake of 99mTc-MIBI, a radioisotope preferentially retained in mitochondria-rich cells. METHODS: This study is a retrospective, single-blind analysis of all double-phase 99mTc-MIBI parathyroid scintigraphy studies performed before surgery in our institution between 1990 and 1995. A total of 18 parathyroid lesions in 14 patients were reviewed. This sample included 11 cases of primary hyperparathyroidism (8 adenomas, 1 adenocarcinoma and 2 hyperplasias) and 3 cases of tertiary hyperparathyroidism secondary to chronic renal failure. RESULTS: Uptake of 99mTc-MIBI in the early phase of scintigraphy was associated with larger parathyroid lesions (1.61 +/- 1.61 ml versus 0.33 +/- 0.27 ml; p < 0.02) and higher serum calcium levels (3.00 +/- 0.41 mM versus 2.67 +/- 0.14 mM; p < 0.02). More importantly, we found that a parathyroid oxyphil cell content greater than 25% was more often associated with a positive uptake of 99mTc-MIBI in the late phase of the test (positive late uptake in 78% of lesions with a high oxyphil cell content versus 33% in lesions with an oxyphil cell content between 1% and 25% and 0% in lesions with no oxyphil cells; p < 0.04). CONCLUSION: These findings suggest that the late retention of 99mTc-MIBI in double-phase scintigraphy is related to parathyroid oxyphil cell content.