Search results for " Analytical"
showing 10 items of 1453 documents
Chromatographic Profiles of the main Secondary Metabolites in the Monarda fistulosa L. Aerial Part
2021
Two different methods of chromatographic analysis have been used in this study for the phytochemical evaluation of main secondary metabolites in the aerial part of bee balm (Monarda fistulosa L.) as the non-officinal medicinal plant of the Lamiaceae Martinov family. The high performance thin layer chromatography (HPTLC) fingerprinting method was developed for the qualitative analyses of phenolic and non-polar compounds in the bee balm herb after its maceration in the solvents of different polarity. Such polyphenols as rosmarinic, caffeic and chlorogenic acids were authentically identified in the methanol extract of herb using HPTLC. Aromatic monoterpenoid thymol was identified by the HPTLC …
On-line database of voltammetric data of immobilized particles for identifying pigments and minerals in archaeometry, conservation and restoration (E…
2016
[EN] A web-based database of voltammograms is presented for characterizing artists' pigments and corrosion products of ceramic, stone and metal objects by means of the voltammetry of immobilized particles methodology. Description of the website and the database is provided. Voltammograms are, in most cases, accompanied by scanning electron microphotographs, X-ray spectra, infrared spectra acquired in attenuated total reflectance Fourier transform infrared spectroscopy mode (ATR-FTIR) and diffuse reflectance spectra in the UV-Vis-region. For illustrating the usefulness of the database two case studies involving identification of pigments and a case study describing deterioration of an archae…
Environmental Monitoring of Cosmetic Ingredients
2018
Abstract Since the late 1990s there has been an increasing concern regarding the release and accumulation of cosmetic ingredients in the environment. These compounds reach the aquatic environment by direct sources, such as bathing activities, but also by indirect sources due to industrial activities, showering, domestic washing, etc., through wastewater treatment plants at which they are not completely removed. As a result, studies have shown that cosmetic ingredients can be found not only in the water phase but also in sediments, soils and living organisms, thus affecting the flora and fauna of the aquatic environment. In this chapter, the fundamental principles of sample preparation metho…
Analytical Solution of the Richards Equation under Gravity-Driven Infiltration and Constant Rainfall Intensity
2020
In the field of soil hydrology, the Richards equation is commonly used to model water flow in unsaturated soils. The high nonlinearity of the Richards equation makes it very challenging to solve analytically for situations that are meaningful in practical applications. In this paper, an exact and simple analytical solution of the Richards equation under gravity-driven infiltration and constant rainfall intensity is derived. First, the solution is presented under Torricelli's law, which mimics the soil hydraulic conductivity function and describes the emptying or filling process of a nonlinear water reservoir. Then, following a similar approach, the solution is extended to the Brooks and Cor…
Recent progress in optical and electrochemical biosensors for sensing of Clostridium botulinum neurotoxin
2018
Abstract Botulinum toxin is a neurotoxic protein which produced from Clostridium botulinum and related species and it block acetylcholine release from presynaptic nerve terminals at the neuromuscular junctions. This toxin is life threatening for millions of people and growing menace to society since causing human botulism. Enzymatic activity of Botulinum neurotoxin within the cell made it hazardous and lead to flaccid paralysis. However, there isn't any reliable and precise remedy for this toxin. Therefore, there is an urgent need for early detection of this toxin in a fast and meticulous way with a robust and cost-effective relationship for real-time monitoring of Botulinum neurotoxin. Sev…
Definition of a Workflow for Web Browsing of 3D Models in Archaeology
2016
The Cultural Heritage (CH) is a fundamental element of promotion of territories and of tourism development. Publishing 3D models of archaeological sites and their three-dimensional reconstruction on the Web is one of the best ways to spread their knowledge. However, many recent scientific researches in this field have highlighted the limitations and difficulties related to the networking of interactive 3D models. The main difficulties are related to the complexity and the size of models, which influence the access speed, and the cost of software and hardware needed for the publication on the WEB. In light of this background, this article describes the further advances of research activities…
Interactions between aroma compounds and beta-lactoglobulin in the heat-induced molten globule state
2010
; he present study aims to elucidate the binding of small hydrophobic ligands onto the molten globule state of β-lactoglobulin (BLG). The conversion of the native BLG into a molten globule state was induced by heat treatment at acidic pH. The molten globule state was evidenced by far and near-UV circular dichroism spectra. β-Ionone and guaiacol exhibited a higher binding ability to BLG in the heat-induced molten globule state compared to unheated BLG, as assessed by protein surface hydrophobicity measurements, using 6-propionyl-2-(dimethylamino)naphthalene (PRODAN) fluorescent probe. The binding sites of the two aroma compounds were determined by 2D nuclear magnetic resonance (NMR) spectro…
Flavor release from salad dressings: sensory and physicochemical approaches in relation with the structure
2000
The effect of process and formulation on sensory perception and flavor release was investigated on salad dressing models. Oil/vinegar emulsions (φ = 0.5, droplet size > 10 μm) with thickeners and a whey protein concentrate were prepared with different fat droplet sizes and different distributions of fat droplet size. The effect of the amount of emulsifier was also tested. Sensory profile analysis was performed by a trained panel and flavor release quantified by dynamic headspace analysis. When the droplet size is increased, the lemon smell and citrus aroma significantly increase, whereas the egg note, mustard, and butter aroma significantly decrease. The concentrations of alcohols and acids…
Multianalytical characterization of pigments from funerary artefacts belongs to the Chupicuaro Culture (Western Mexico): Oldest Maya blue and cinnaba…
2019
Abstract The colours used in Pre-Hispanic Mesoamerica to decorate walls, codices or artefacts have been the subject of numerous studies, with particular attention to Maya blue, red and white pigments. However, most of these studies have been focused on emblematic cultures of the Classic period (ca. 300–1000 CE), such as Teotihuacan and Maya cultures. This work proposes a new chronology of the preparation and use of these pigments, particularly Maya blue, by analysing samples of the Pre-Classic period (ca. 1800 BCE–300 CE). The samples belong to ceremonial artefacts decorated with blue, red and white pigments, in a funerary context from the Chupicuaro culture, which was developed between 600…
Volatile phenol determination in wine
1981
International audience