Search results for "feature"
showing 10 items of 4091 documents
The Neanderthalian molar from Hunas, Germany
2005
Abstract In this paper, we present a well-preserved isolated human molar found in 1986 in the Hunas cave ruin, south-east Bavaria. The tooth was located at the bottom of layer F2, which belongs to a long stratigraphic sequence comprising faunal remains as well as archaeological levels (Mousterian). A stalagmite from layer P at the base of the stratigraphic sequence was recently dated to 79.373±8.237 ka (base) and 76.872±9.686 ka (tip) by TIMS-U/Th (Stanford University). We identified the tooth as a right (possibly third) mandibular molar. Characteristic parameters such as crown and root morphology, fissure pattern, enamel thickness, occlusal and interproximal wear, dental dimensions and ind…
Variation of the BrO/SO2 molar ratio in the plume of Tungurahua volcano between 2007 and 2017 and its relationship to volcanic activity
2019
International audience; Recent long-term observations of the bromine monoxide (BrO) to sulphur dioxide (SO2) molar ratio in volcanic plumes have suggested a link between changes in the BrO/SO2 ratio and the volcanic activity. Nevertheless, understanding of the mechanisms determining this link is still limited due to the lack of studies on volcanic bromine release from the melt into the atmosphere. We present the results of 10 years (2007–2017) of observations of the BrO/SO2 molar ratio in the volcanic plume of Tungurahua volcano, Ecuador. Following the nearly continuous eruptive activity from 1999 to 2008, Tungurahua showed alternating phases of eruptive activity separated by periods of qui…
Features and ecological significance of benchmark soils of the Moldavian plateau, Romania
2016
Features and ecological significance of benchmark soils of the Moldavian plateau, Romania
Automatic Assessment of Depression Based on Visual Cues: A Systematic Review
2019
International audience; Automatic depression assessment based on visual cues is a rapidly growing research domain. The present exhaustive review of existing approaches as reported in over sixty publications during the last ten years focuses on image processing and machine learning algorithms. Visual manifestations of depression, various procedures used for data collection, and existing datasets are summarized. The review outlines methods and algorithms for visual feature extraction, dimensionality reduction, decision methods for classification and regression approaches, as well as different fusion strategies. A quantitative meta-analysis of reported results, relying on performance metrics r…
Speciation of vanadium in urban, industrial and volcanic soils by a modified Tessier method
2016
Vanadium (V) concentrations in industrial, urban and volcanic soils were sequentially extracted using a modified Tessier's method. The voltammetric technique was used to determine V concentrations in solutions obtained from the various extraction steps. At the reference stations, the V concentrations (sum of four individual fractions) in soils ranged from 0.72 to 0.24 g kg(-1) dry weight (d.w.) with a mean value of 0.18 g kg(-1) d.w. V concentrations in soils of the Palermo urban area ranged from 0.34 to 2.1 g kg(-1) d.w., in the Milazzo (industrial) area between 0.26 and 5.4 g kg(-1) d.w. and in the volcanic area near Mt. Etna from 0.91 to 2.9 g kg(-1) d.w. When the V concentrations around…
Origin and correction of the deviations in retention times at increasing flow rate with Chromolith columns.
2010
Chromoliths can be used at flow rates beyond those feasible for conventional microparticulate packed columns. Ideally, the plots of the retention time versus the inverse of delivered flow rate should exhibit y-intercept of zero. However, significant positive deviations correlating with the solute polarity were observed for several compounds chromatographed with a Chromolith column, owing to the increased system pressure. Consequently, the dead time marker exhibits a smaller deviation, making the retention factors depend on the flow rate. Chromoliths are made of a silica-based monolith encapsulated within a PEEK tube, and should suffer larger stress with pressure than stainless steel columns…
Preparation of organic monolithic columns in polytetrafluoroethylene tubes for reversed-phase liquid chromatography
2017
[EN] In this work, a method for the preparation and anchoring of polymeric monoliths in a polytetrafluoroethylene (PTFE) tubing as a column housing for microbore HPLC is described. In order to assure a covalent attachment of the monolith to the inner wall of the PTFE tube, a two-step procedure was developed. Two surface etching reagents, a commercial sodium naphthalene solution (Fluoroetch®), or mixtures of H2O2 and H2SO4, were tried and compared. Then, the obtained hydroxyl groups on the PTFE surface were modified by methacryloylation. Attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy and scanning electron microscopy (SEM) confirmed the successful modification…
Phosphatidylcholine covalently linked to a methacrylate-based monolith as a biomimetic stationary phase for capillary liquid chromatography
2015
Abstract In this study a strategy to immobilize phospholipids onto a polymer-based stationary phase is described. Methacrylate-based monoliths in capillary format (150 × 0.1 mm) were modified by soybean phosphatidylcholine through 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide coupling to obtain stationary phases suitable to mimic cell surface membranes. The covalent coupling reaction involves the phosphate group in phospholipids; therefore, the described methodology is suitable for all types of phospholipids. Immobilization of soy bean phosphatidylcholine on the monolith was confirmed by attenuated total reflectance Fourier transform infrared spectroscopy and gas chromatography-mass spectro…
3D printed fluidic platform with in-situ covalently immobilized polymer monolithic column for automatic solid-phase extraction
2020
Abstract In this work, 3D stereolithographic printing is proposed for the first time for the fabrication of fluidic devices aimed at in-situ covalent immobilization of polymer monolithic columns. Integration in advanced flow injection systems capitalized upon programmable flow was realized for fully automatic solid-phase extraction (SPE) and clean-up procedures as a ‘front-end’ to on-line liquid chromatography. The as-fabricated 3D-printed extraction column devices were designed to tolerate the pressure drop of forward-flow fluidic systems when handling large sample volumes as demonstrated by the determination of anti-microbial agents, plastic additives and monomers as models of emerging co…
Preparation of monolithic polymer-magnetite nanoparticle composites into poly(ethylene-co-tetrafluoroethylene) tubes for uses in micro-bore HPLC sepa…
2021
[EN] This paper describes the fabrication of a novel microbore monolithic column modified with magnetite nanoparticles (MNPs) prepared in a poly(ethylene-co-tetrafluoroethylene) (EFTE) tubing, and its application as stationary phase for the chromatographic separation of phosphorylated compounds. In order to obtain the composite column, a two-step procedure was performed. The formation of a glycidyl methacrylate-based monolith inside the activated ETFE tube was firstly carried out. Then, two incorporation approaches of MNPs in monoliths were investigated. The generic polymer was modified with 3-aminopropyltrimethoxysilane (APTMS) to be subsequently attached to MNP surfaces. Alternatively, AP…