Search results for "lithic"
showing 10 items of 392 documents
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…
Photografted fluoropolymers as novel chromatographic supports for polymeric monolithic stationary phases
2018
[EN] In this study, porous polymer monoliths were in situ synthesized in fluoropolymers tubing to prepare microbore HPLC columns. To ensure the formation of robust homogeneous polymer monoliths in these housing supports, the inner surface of fluoropolymer tubing was modified in a two-step photografting process. Raman spectroscopy and scanning electron microscopy (SEM) confirmed the successful modification of the inner poly(ethylene-co-tetrafluoroethylene) (ETFE) wall and the subsequent attachment of a monolith onto the wall. Poly(glycidyl methacrylate-co-divinylbenzene), poly(butyl methacrylate-co-ethyleneglycol dimethacrylate) and poly(styrene-co-divinylbenzene) monoliths were in situ synt…
Application of multivariate statistics to the problems of upper palaeolithic and mesolithic samples
1987
Multivariate statistics (discriminant function analysis and principal component analysis) have been applied to a broad sample of Upper Paleolithic and mesolithic skulls. In addition to some methodological problems concerning the evaluation of missing data by principal component analysis, we discussed the possibility of misclassifications (14%).
Report on the first season of German-Kurdish excavations at Muqable in 2015
2017
In 2015, a new excavation project entitled “Kurdish-German Archaeological Mission in Dohuk” (KUGAMID) was launched. It is organized as a joint project between the University of Tübingen and the Department of Antiquities of Dohuk and is jointly directed by Peter Pfälzner (Tübingen) and Hassan Ahmad Qasim (Dohuk). Three sites were selected for excavation: Bassetki, Muqable I and Muqable III. The following report will summarize the results of the first season of excavations at the two neighbouring mounds of Muqable I and Muqable III, located approximately 5 km southeast of Bassetki and 23 km west of Dohuk in the Autonomous Region of Kurdistan in Iraq. The first season of excavations at Muqable…
Explorations, implantations et diffusions : le "phénomène" campaniforme en France méditerranéenne
2004
In the south-east of France, the first Bell Beaker expansion is manifested by the presence of isolated ceramics but also by a series of settlements established in contact with the indigenous populations. Analysis of the assemblages, their composition and their distribution makes it possible to propose a model of the appearance and development of the Bell Beaker phenomenon but also the probable origin of the elements present in this area.
Neolithic ceramic findings from western Sicily. Chemical – physical and mineralogical characterization
2001
This paper presents the results of a study that is part of a wider research program regarding the knowledge of the initial living phases of Sicilian agricultural and pastoral societies.Three ceramic samples attributed to the medium initial Neolithic (NEO1 and NEO2) and to the first neolithic (NEO3), recovered in two different archaeological sites of the western Sicily, have been analysed. Chemical, mineralogical and spectroscopic data point out a similarity between NEO1 and NEO3 samples; compositional and morphological differences instead have been observed in the NEO2 sample. The firing temperatures of the samples have been estimated by Mössbauer spectroscopy; they are lower than 500°C for…
The Gravettian occipital bone from the site of Malladetes (Barx, Valencia, Spain)
2002
Abstract The juvenile occipital bone from the site of Malladetes in Valencia (Spain) is described and compared with other European Pleistocene representatives of the genus Homo . This specimen derives from a Gravettian cultural context and has been AMS radiocarbon-dated to 25,120±240 years bp . As such, it provides evidence on early modern human anatomy from the Central Mediterranean region of the Iberian peninsula. The clear evidence for a late survival of Neandertals in southern Iberia, has led to considerable debate surrounding the biological and cultural interactions between these Pleistocene humans and their early modern human successors, and it is within this context that the Malladet…
The evolution and changing ecology of the African hominid oral microbiome
2021
Significance The microbiome plays key roles in human health, but little is known about its evolution. We investigate the evolutionary history of the African hominid oral microbiome by analyzing dental biofilms of humans and Neanderthals spanning the past 100,000 years and comparing them with those of chimpanzees, gorillas, and howler monkeys. We identify 10 core bacterial genera that have been maintained within the human lineage and play key biofilm structural roles. However, many remain understudied and unnamed. We find major taxonomic and functional differences between the oral microbiomes of Homo and chimpanzees but a high degree of similarity between Neanderthals and modern humans, incl…