Search results for " analytic"
showing 10 items of 1718 documents
2020
Strontium isotopes in biogenic apatite, especially enamel, are widely employed to determine provenance and track migration in palaeontology and archaeology. Body tissues record the 87Sr/86Sr of bioavailable Sr of ingested food and water. To identify non-local individuals, knowledge of the 87Sr/86Sr of a non-migratory population is required. However, varying factors such as tissue turnover rates, feeding selectivity, Sr content, digestibility of food, and the ingestion of mineral dust can influence body tissue 87Sr/86Sr. To evaluate the Sr contribution of diet and water to mammalian hard tissues 87Sr/86Sr, controlled feeding studies are necessary. Here we present 87Sr/86Sr from controlled fe…
Untargeted metabolomics to explore the oxidation processes during shelf life of pork patties treated with guarana seed extracts
2019
The changes of metabolites in pork patties with different antioxidants added (control without antioxidants, 200 mg kg(-1) butylated hydroxytoluene (BHT) and 250 mg kg(-1) guarana seed extracts (GSEs)) under modified atmosphere (80% O-2 and 20% CO2) for 18 days of refrigerated storage were evaluated. Untargeted metabolomic approach based on UHPLC-ESI-QTOF-MS analysis was applied. GSE phytochemical profile revealed a wide variety of compounds (caffeine, glycerol 1-propanoate, amino acids, alkaloids and glycerophospholipids), together with antioxidants (tyrosols, procyanidins and flavonoids). Important differences in BHT and GSE patties metabolomic profiles were found during storage. Most of t…
High Biological Value Compounds Extraction from Citrus Waste with Non-Conventional Methods.
2020
Citrus fruits are extensively grown and much consumed around the world. Eighteen percent of total citrus cultivars are destined for industrial processes, and as a consequence, large amounts of waste are generated. Citrus waste is a potential source of high biological value compounds, which can be used in the food, pharmaceutical, and cosmetic industries but whose final disposal may pose a problem due to economic and environmental factors. At the same time, the emerging need to reduce the environmental impact of citrus waste and its responsible management has increased. For these reasons, the study of the use of non-conventional methods to extract high biological value compounds such as caro…
Chiral Serum Pharmacokinetics of 4-Fluoroamphetamine after Controlled Oral Administration
2021
Abstract Over the last two decades, misuse of 4-fluoroamphetamine (4-FA) became an emerging issue in many European countries. Stimulating effects last for 4–6 hours and can impact psychomotor performance. The metabolism of amphetamine-type stimulants is stereoselective and quantification of (R)- and (S)-enantiomers has been suggested for assessing time of use. To date, no data on enantioselective pharmacokinetics is available for 4-FA in serum samples. An enantioselective liquid chromatography−tandem mass spectrometry (LC–MS-MS) method was developed using a chiral Phenomenex® Lux 3 μm AMP column. Validation of the method showed satisfactory selectivity, sensitivity, linearity (0.5–250 ng/mL…
The emerging role of 3D printing in the fabrication of detection systems
2021
Abstract 3D printing is fast evolving as an additive manufacturing technique that has been adopted in (bio)analytical science because of the ample variety of materials and technologies currently available for highly affordable prototyping. This review focuses on the unique characteristics of 3D printing for manufacturing of optical and electrochemical detection systems, and sampling interfaces for analytical purposes using fused deposition modelling, vat polymerization (stereolithography and digital light processing) and photopolymer inkjet printing. The majority of works surveyed within the time span of mid-2018 to mid-2020 encompassed the fabrication of several components of the detection…
ATR-Spin: an open-source 3D printed device for direct cytocentrifugation onto attenuated total reflectance crystals.
2021
Infrared Spectroscopy (IR) enables the direct and rapid characterization of cells at the molecular level. Achieving a rapid and consistent cell preparation is critical for the development of Point-of-Care diagnostics for cell analysis. Here we introduce an open-source, 3D printed device for integrating the isolation, preconcentration, and measurement of attenuated total reflectance IR spectra of cells from biofluids. The tool comprises a disposable card for cytocentrifugation, equipped with magnets, which allows reproducible integration into the pathlength of the IR spectrophotometer. Preliminary results using cell media containing A459 cells indicate that this system enables a qualitative …
Determination of mercury at picogram level in natural waters with inductively coupled plasma mass spectrometry by using 3D printed metal scavengers
2019
The determination of ultra-trace concentrations of Hg in natural water samples via preconcentration using 3D printed metal scavenger technique followed by inductively coupled plasma mass spectrometry (ICP-MS) was developed. The determination of Hg in certified reference material ERM-CA615 (groundwater) was performed with high accuracy and precision resulting in recovery of 100 ± 3% and RSD <2.5%, respectively. Selective laser sintering (SLS) 3D printing was used to fabricate the scavengers using a mixture of polyamide-12 powder with thiol-functionalized silica. The preconcentration procedure is based on the adsorption of Hg on the scavenger and followed by elution of the preconcentrated Hg …
Enabling Sociability When Using Virtual Reality Applications : A Design Science Research Approach
2019
Immersive virtual reality applications aim at providing an all-encompassing spatial experience where a user can feel like being in another world or dimension. The systems are inherently designed for individual use as the devices disconnect the user from the physical environment. However, the applications are seldom used alone. Specifically, when used for sales and marketing, the user often needs help from other people but also benefits from social interaction as a part of the experience. Design research methodology is applied to three iterative development versions of a virtual-reality application. The focus of the evaluation of the artifacts is in the social use emphasizing three sociabili…
The maximum carbonyl ratio (MCR) as a new index for the structural classification of secondary organic aerosol components
2021
RATIONALE Organic aerosols (OA) account for a large fraction of atmospheric fine particulate matter and thus are affecting climate and public health. Elucidation of the chemical composition of OA is the key for addressing the role of ambient fine particles at the atmosphere-biosphere interface and mass spectrometry is the main method to achieve this goal. METHODS High-resolution mass spectrometry (HRMS) is on its way to becoming one of the most prominent analytical techniques, also for the analysis of atmospheric aerosols. The combination of high mass resolution and accurate mass determination allows the elemental compositions of numerous compounds to be easily elucidated. Here a new parame…
Łojasiewicz exponents, the integral closure of ideals and Newton polyhedra
2003
We give an upper estimate for the Łojasiewicz exponent $\ell(J,I)$ of an ideal $J\subseteq A(K^{n})$ with respect to another ideal I in the ring $A(K^{n})$ of germs analytic functions $f$ : $(K^{n},\mathrm{O})\rightarrow K$ , where $K=C$ or $R$ , using Newton polyhedrons. In particular, we give a method to estimate the Łojasiewicz exponent $\alpha_{0}(f)$ of a germ $f\in A(K^{n})$ that can be applied when $f$ is Newton degenerate with respect to its Newton polyhedron.