Search results for "Chemical composition"
showing 10 items of 377 documents
Biochemical composition of salivary stones in relation to stone-and patient-related factors
2018
Background Salivary stones are calcified structures most often found in the main duct of the submandibular or parotid salivary gland. They contain of a core surrounded by laminated layers of organic and inorganic material. Material and Methods Submandibular and parotid sialoliths (n=155) were collected at the department of Oral and Maxillofacial surgery of a general hospital between February 1982 and September 2012. The weight of the sialoliths was determined and the consistency was subjectively classified. Subsequently, the biochemical composition of the stones was determined by wet chemical methods or FT-IR spectrometry. Age and gender of the patients were retrieved from their medical rec…
Association between nutritional values of hays fed to horses and sensory properties as perceived by human sight, touch and smell
2019
International audience; Although hay is the foundation of most equine diets, horse owners rarely ask for biochemical analysis and the routine practice is to choose hay based on its 'perceived' nutritional value. The present study aimed at exploring the relationship between sensory properties as perceived by sight, touch and smell, and the nutritional value of hay measured by biochemical analysis using a 'free sorting task' method. Fifty-four non-expert participants were asked individually to: (1) observe 21 hays samples, (2) group together hays that they perceived as similar for each of the three modalities (hay appearance, odour or texture) and (3) characterize each formed group with a max…
Case study: inorganic pollutants associated with particulate matter from an area near a petrochemical plant.
2004
The area of Gela (Sicily, Italy) contains one of the largest petroleum refineries in Europe and also has several oil fields both on land and offshore. This paper discusses how the oil refinery and traffic-related air pollution affect the chemical composition of airborne particulate matter over the town of Gela, using pine needles and urban road dust as the means of survey. Forty-one samples of pine needles from Pinus halepensis (Mill.) and two composite samples of roadway dust, each subdivided into six size fractions, were analyzed for major and trace elements. Information on the natural or anthropogenic origin of the observed heavy metals was deduced from factor analysis and element distri…
Dust, Metals and Metalloids in the Environment: From Air to Hair .
2013
Billions tons of particulate matter, made up of inorganic and organic compounds, are released every year into the atmosphere, from both anthropogenic and natural sources. The latter, which include geogenic material from erosion, agriculture, sea spray and volcanic activity, account for about 97% of the total mass of particles. The contribution of anthropogenic sources, about 3%, is more pronounced in industrialised and also in urban areas, where vehicular traffic is one of the most important sources. When examining the health impact, in addition to mass level and size, two other main characteristics of particulate matter need to be considered: its nature and chemical composition. These para…
Enhanced organic mass fraction and decreased hygroscopicity of cloud condensation nuclei (CCN) during new particle formation events
2010
In a forested near-urban location in central Germany, the CCN efficiency of particles smaller than 100 nm decreases significantly during periods of new particle formation. This results in an increase of average activation diameters, ranging from 5 to 8% at supersaturations of 0.33% and 0.74%, respectively. At the same time, the organic mass fraction in the sub-100-nm size range increases from approximately 2/3 to 3/4. This provides evidence that secondary organic aerosol (SOA) components are involved in the growth of new particles to larger sizes, and that the reduced CCN efficiency of small particles is caused by the low hygroscopicity of the condensing material. The observed dependence of…
Brown Carbon Aerosol in Urban Xi'an, Northwest China: The Composition and Light Absorption Properties.
2018
Light-absorbing organic carbon (i.e., brown carbon or BrC) in the atmospheric aerosol has significant contribution to light absorption and radiative forcing. However, the link between BrC optical properties and chemical composition remains poorly constrained. In this study, we combine spectrophotometric measurements and chemical analyses of BrC samples collected from July 2008 to June 2009 in urban Xi'an, Northwest China. Elevated BrC was observed in winter (5 times higher than in summer), largely due to increased emissions from wintertime domestic biomass burning. The light absorption coefficient of methanol-soluble BrC at 365 nm (on average approximately twice that of water-soluble BrC) w…
Anti-Pseudomonas aeruginosa activity of hemlock (Conium maculatum, Apiaceae) essential oil
2018
Conium maculatum is a nitrophilous weed belonging to the Apiaceae family and occurring in hedgerows, pastures, waste ground, along rivers and roadsides. Little is known on the chemistry and bioactivity of other secondary metabolites occurring in the plant. In the present work, we have analysed the chemical composition and antimicrobial activity of the essential oils hydrodistilled from leaves and inflorescenes of C. maculatum growing in Sicily, Italy. The composition of essential oils was achieved by gas chromatography-mass spectrometry (GC-MS) analysis, whereas the inhibitory effects on the growth of two Gram negative strains, namely Escherichia coli and Pseudomonas aeruginosa were assesse…
Chemical composition of the essential oil from Thapsia garganica L. (Apiaceae) grown wild in Sicily and its antimicrobial activity.
2015
In this study, the chemical composition of the essential oil from flowers and leaves of Thapsia garganica L. collected in Sicily was evaluated by GC and GC-MS. The main components of T. garganica flower oil (T.f.) were chamazulene (58.3%), humulene oxide II (9.0%), tricosane (8.2%) and pentacosane (8.2%). Also the oil from leaves (T.l.) was characterised by high content of chamazulene (49.2%). Other abundant metabolites were 1,4-dimethylazulene (18.5%), (E)-phytol (6.3%) and neophytadiene (5.1%). The comparison with other studied oils of genus Thapsia is discussed. Antimicrobial activity against several micro-organisms, including some ones infesting historical art craft, was also determined.
Chemical composition of essential oils of Anthemis secundiramea Biv. subsp. secundiramea (Asteraceae) collected wild in Sicily and their activity on …
2016
In the present study, the chemical composition of the essential oil from the aerial parts of Anthemis secundiramea Biv. subsp. secundiramea L. collected in Sicily was evaluated by GC and gas chromatography–mass spectrometry. The main components of A. secundiramea were (Z)-lyratyl acetate (14.6%), (Z)-chrysanthenyl acetate (9.9%), (Z)-chrysanthenol (8.7%) and (E)-chrysanthenyl acetate (7.7%). The comparing with other studied oils of genus Anthemis belonging to the same clade is discussed. Antibacterial and antifungal activities against some micro-organisms infesting historical art craft, were also determined.
Chemical Profiling of Polyfloral Belgian Honey: Ellagic Acid and Pinocembrin as Antioxidants and Chemical Markers
2017
Chemical profiling of northern Belgian polyfloral honeys was performed to analyse their phenolic compound content (flavonoids and phenolic acids). First, samples were subjected to a standard analysis of their physicochemical properties, and then, the phenolic fraction was isolated and analysed using a HPLC/PAD method. All of the tested honeys showed a common and specific phenolic profile that could be the basis for the differentiation of polyfloral honeys of the Antwerp region from other polyfloral honeys. Chromatographic data indicated a high content of ellagic acid (9.13–13.66 mg/100 g honey), as well as the flavonoid pinocembrin (1.60–1.85 mg/100 g honey) in these honeys. Ellagic acid, a…