Intergranular Oxidation of Nickel-Base Alloys: Potentialities of Focused Ion Beam Tomography

Oxidation of Metals - The present work focuses on the intergranular oxidation of Alloy 600 and its weld material Alloy 82 after exposure in simulated primary water at 340–360 °C...     

Characterization of mechanical properties of suspension plasma sprayed TiO2 coatings using scratch test

The study aimed at characterizing mechanical properties of TiO₂ coatings obtained by the use of aqueous suspensions of fine rutile and anatase particles onto metal substrates. Thickness of the coatings was found with the use of optical microscope observations of metallographical cross-sections. The coatings morphology was found with scanning electron microscope (SEM) and their phase composition was determined by X-ray diffraction method. The mechanical properties were characterized using scratch test. The test enabled to characterize the adhesion of coatings by determination of critical force necessary to peel off the coatings from the substrate and, on the other hand, to estimate their cohesion by the measurement of the scratch hardness. The hardness was calculated using the width of the scratch and the value of force applied. The design of experiments (DOE) of spraying with the use of a 2³ full factorial plan was applied to rutile powder. The coatings were sprayed onto aluminium substrate. The DOE enabled to find the effects of three principal parameters, i.e. electric power input to plasma, spray distance and suspension feed rate onto coating adhesion expressed by critical force. A preliminary data for anatase powder sprayed with one set of operational parameters onto stainless steel substrate are also shown.     

Inhibition of Very Long Chain Fatty Acids Synthesis Mediates PI3P Homeostasis at Endosomal Compartments

A main characteristic of sphingolipids is the presence of a very long chain fatty acid (VLCFA) whose function in cellular processes is not yet fully understood. VLCFAs of sphingolipids are involved in the intracellular traffic to the vacuole and the maturation of early endosomes into late endosomes is one of the major pathways for vacuolar traffic. Additionally, the anionic phospholipid phosphatidylinositol-3-phosphate (PtdIns (3)P or PI3P) is involved in protein sorting and recruitment of small GTPase effectors at late endosomes/multivesicular bodies (MVBs) during vacuolar trafficking. In contrast to animal cells, PI3P mainly localizes to late endosomes in plant cells and to a minor extent to a discrete sub-domain of the plant’s early endosome (EE)/trans-Golgi network (TGN) where the endosomal maturation occurs. However, the mechanisms that control the relative levels of PI3P between TGN and MVBs are unknown. Using metazachlor, an inhibitor of VLCFA synthesis, we found that VLCFAs are involved in the TGN/MVB distribution of PI3P. This effect is independent from either synthesis of PI3P by PI3-kinase or degradation of PI(3,5)P₂ into PI3P by the SUPPRESSOR OF ACTIN1 (SAC1) phosphatase. Using high-resolution live cell imaging microscopy, we detected transient associations between TGNs and MVBs but VLCFAs are not involved in those interactions. Nonetheless, our results suggest that PI3P might be transferable from TGN to MVBs and that VLCFAs act in this process.     

Preparation of 5‐Membered Rings via Radical Addition‐ Translocation‐Cyclization (RATC) Processes Mediated by Diethyl Thiophosphites

A practical method for the formation of thiophosphonates bearing functionalized monocyclic, fused bicyclic and spirocyclic residues is presented. The procedure requires the easily available terminal alkynes as starting materials as well as commercially and readily available reagents such as diethyl thiophosphite. The experimental procedure consists of a one‐pot process without any slow addition of one of the reagents.     

Self-assembly and characterization of layered double hydroxide/DNA hybrids

The purpose of this study was to control the fabrication of new labile supramolecular assemblies by formulating associations of DNA molecules with inorganic layered double hydroxides (LDHs). The results show that LDH/DNA hybrids synthesized by a coprecipitation route involving the in situ formation of LDHs around DNA molecules acting as templates were characterized by a lamellar organization, with DNA molecules sandwiched between hydroxide layers, exhibiting a regular spacing of 1.96 nm. Our results indicate that labile complexes resulting from the association of nucleic acids and inorganic materials can be obtained not only by anion exchange but also by a direct self-assembly route.     

Heterogeneity of the adsorption mechanism of low molecular weight compounds in reversed-phase liquid chromatography

The retention mechanism in RPLC mode was investigated based on the acquisition of adsorption isotherm data by frontal analysis measurements and their modeling. This work is a review of the results of four years of adsorption data measurements. The data were acquired on a wide variety of brands of C18-silica columns (from Akzo Nobel, Bishoff, Hypersil, Merck, Phenomenex, Supelco, Vydac, and Waters) with several low molecular weight compounds such as phenol (94 g/mol), caffeine (194 g/mol), tryptophan (204 g/mol), sodium 2-naphthalenesulfonate (235 g/mol), and propranololium chloride (295 g/mol). The mobile phase was a mixture of methanol and water at variable composition. The adsorption isotherms were all convex upward (langmuirian), and the degree of heterogeneity of the adsorption system was determined from the calculation of the adsorption energy distribution using the expectation-maximization method. The adsorption isotherm parameters (number of types of adsorption sites, surface concentration of each type of site, and difference between the adsorption energies E(i) - E(j) on sites i and j), obtained from the mathematical fit of the adsorption data to the appropriate multi-Langmuir adsorption isotherm model, were analyzed and compared. The results allow the drawing of general conclusions regarding the relationships between the size of the analyte and the adsorption properties (saturation capacities, adsorption energies) characterizing the retention mechanism in RPLC mode for neutral, anionic, and cationic compounds.     

Dielectric cell response in highly conductive buffers

We present a novel method for the identification of live and dead T-cells, dynamically flowing within highly conductive buffers. This technique discriminates between live and dead (heat treated) cells on the basis of dielectric properties variations. The key advantage of this technique lies in its operational simplicity, since cells do not have to be resuspended in isotonic low conductivity media. Herein, we demonstrate that at 40 MHz, we are able to statistically distinguish between live and dead cell populations.     

Experimental behaviour of high-performance concrete in confined tension

Prestressed concrete is commonly used in a wide range of applications, yet on rare occasions spalling problems have been reported for concrete structures prestressed in two directions. The tensile behaviour of concrete may be affected by prestressing; consequently a number of experiments have been performed to reproduce this load combination on laboratory samples. Tests were carried out in a compression-tension triaxial cell suitable for the independent application of a lateral confining pressure, as well as a direct axial tension load. Results reveal a measurable but limited reduction in concrete tensile strength with a confining pressure of a similar magnitude as the prestress (order of magnitude of 10 MPa). Further experiments were conducted at higher confining pressures, in both confined tension and in triaxial extension, in order to generate an overview of limit state behaviour for the studied high performance concrete.     

Near-infrared spectroscopy applications for high-throughput phenotyping for cassava and yam: A review

The review aimed to identify the different high-throughput phenotyping (HTP) techniques that used for quality evaluation in cassava and yam breeding programmes, and this has provided insights towards the development of metrics and their application in cassava and yam improvements. A systematic review of the published research articles involved the use of NIRS in analysing the quality traits of cassava and yam was carried out, and Scopus, Science Direct, Web of Sciences and Google Scholar were searched. The results of the review established that NIRS could be used in understanding the chemical constituents (carbohydrate, protein, vitamins, minerals, carotenoids, moisture, starch, etc.) for high-throughput phenotyping. This study provides preliminary evidence of the application of NIRS as an efficient and affordable procedure for HTP. However, the feasibility of using mid-infrared spectroscopy (MIRS) and hyperspectral imaging (HSI) in combination with the NIRS could be further studied for quality traits phenotyping.     

Effects of slope exposure,altitude and yield on coffee quality in two altitude terroirs of Costa Rica,Orosi and Santa María de Dota

This study assessed the effects of slope exposure, altitude and yield on several cup quality criteria of coffees from two altitude terroirs of Costa Rica, Orosi (between 1020 and 1250 m above sea level) and Santa María de Dota (between 1550 and 1780 m above sea level). East‐facing slopes gave beverages with generally superior attributes, probably owing to better exposure to morning sunlight. These beverages were mainly more acid: at Orosi an acidity score of 2.73 out of 5 was obtained (3.64 for Santa María de Dota) for eastern exposures, as opposed to 2.36 on average (3.28 for Santa María de Dota) for other exposures. In addition, a positive relation was found between altitude and taster preferences in both terroirs. A negative relation was also found between yield and beverage acidity at Santa María de Dota, where some coffee trees produced up to 13 kg of coffee cherry. Coffees from Orosi were characterised by a floral flavour, which depended on slope exposure, whilst coffees from Santa María de Dota displayed a chocolate taste, which was more marked at high altitude. In both terroirs the caffeine, trigonelline, fat, sucrose and chlorogenic acid contents were not well correlated with the sensory characteristics. Copyright © 2005 Society of Chemical Industry