Search results for "IONIZATION"
showing 10 items of 1255 documents
Fast and nonselective on-line mass separation of neutron-rich isotopes produced in proton-induced fission
1989
Abstract On-line mass separation of short-lived radionuclides, based on the use of thermalized primary ions from nuclear reactions, termed as an ion guide method, has recently been widely applied in the spectroscopy of both proton-rich and neutron-rich exotic nuclei. The technique has been found to be applicable to all elements and it has allowed the detection of the mass-analyzed activities with half-lives as short as 0.1 ms. The ion guide isotope separator on-line, IGISOL, has recently been used to discover over ten new short-lived isotopes or isomers produced in the nearly symmetric fission of uranium induced by 20 MeV protons. In addition to applications in nuclear-structure physics and…
Recent Advances in On-Line Laser Spectroscopy
2015
At radioactive ion beam facilities, particle accelerators are employed to induce nuclear reactions in order to provide short-lived nuclei for immediate study using a variety of spectroscopic techniques. These exotic isotopes/isomers are formed into a beam of fast ions, which are mass analyzed in-flight during transport to a chosen experimental set-up. As an additional filter, the atomic level structure provides a selective fingerprint, which distinguishes one element from another due to the varying numbers of protons and electrons. This property is exploited in laser ion sources whereby high power, pulsed tuneable laser radiation is used to excite and ionize the atom in order to enhance the…
Analysis of pecan nut ([i]Carya illinoinensis[/i]) unsaponifiable fraction. Effect of ripening stage on phytosterols and phytostanols composition
2014
Changes in 4-desmethylsterol, 4-monomethylsterol, 4,4-dimethylsterol and phytostanol composition were quantitatively and qualitatively investigated during the ripening of three varieties of Tunisian-grown pecan nuts (Mahan, Moore and Burkett). These components have many health benefits, especially in lowering LDL-cholesterol and preventing heart disease. The phytosterol composition of whole pecan kernel was quantified by Gas Chromatography-Flame Ionisation Detection (GC-FID) and identified by Gas Chromatography-Mass Spectrometry (GC-MS). Fifteen phytosterols and one phytostanol were quantified. The greatest amount of phytosterols (2852.5 mg/100 g of oil) was detected in Mahan variety at 20 …
Assessment of Human Exposure to Deoxynivalenol, Ochratoxin A, Zearalenone and Their Metabolites Biomarker in Urine Samples Using LC-ESI-qTOF.
2021
Human are exposed to a wide range of mycotoxins through dietary food intake, including processed food. Even most of the mycotoxin exposure assessment studies are based on analysis of foodstuffs, and evaluation of dietary intake through food consumption patterns and human biomonitoring methods are rising as a reliable alternative to approach the individual exposures, overcoming the limitations of the indirect dietary assessment. In this study, human urine samples were analyzed, seeking the presence of deoxynivalenol (DON), ochratoxin A (OTA), zearalenone (ZEA), and their metabolites. For this purpose, 40 urine samples from female and male adult residents in the city of Valencia (Spain) were …
Application of hybrid linear ion trap-high resolution mass spectrometry to the analysis of mycotoxins in beer
2011
This paper reports the application of liquid chromatography electrospray ionization ion trap-orbitrap mass spectrometry for the determination of 18 mycotoxins (aflatoxins, fumonisins, trichothecenes, ochratoxin A, sterogmatocystin, beauvaricin, zearalenone and zearalenol) in beer. The extraction procedure was carried out by solid phase extraction (SPE): SPE columns were conditioned with acetonitrile/methanol and water. Beer was loaded onto the column which was washed with water. In these conditions, the recoveries were more than 65% and the relative standard deviation (RSD) were below 18%. The lowest limits of quantification (LLOQ) ranged from 9 to 155 ng ml(-1). Matrix-matched calibration …
Occurrence of Free and Conjugated Mycotoxins in Aromatic and Medicinal Plants and Dietary Exposure Assessment in the Moroccan Population.
2021
Aromatic and medicinal plants (AMPs), as herbal material, are subjected to contamination by various mycotoxin-producing fungi, either free and conjugated. Such a problem is associated with poor storage practices, and lack of adopting good agricultural practices and good harvesting practices. Nevertheless, AMPs are poorly investigated. The purpose of this study was to investigate the co-occurrence of 15 mycotoxins (four aflatoxins (AFB1, AFB2, AFG1, and AFG2), ochratoxin A (OTA), beauvericin (BEA), four enniatins (ENA, ENA1, ENB, and ENB1), zearalenone (ZEN), alternariol (AOH), tentoxin (TENT), T-2, and HT-2 toxins) in 40 samples of AMPs frequently consumed in Morocco by using liquid chromat…
Levels of ochratoxin A in wheat and maize bread from the central zone of Portugal.
2007
Ochratoxigenic fungi are natural contaminants of cereal and the produced toxins are harmful to humans and animals. Ochratoxin A (OTA) is among the most important mycotoxins, and the International Agency for Research on Cancer (IARC) classifies it as possibly carcinogenic to humans (group 2B). A total of 61 samples of bread from the central zone of Portugal were analysed for OTA by liquid chromatography (LC) with fluorescence detection (FD). For confirmation two procedures were applied, methyl ester derivatization with boron trifluoride-methanol and liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI/MS/MS). As far as we know, this is the first report where on-line…
Effects of water on gas chromatographic column efficiency measurements applied to on-column injections of volatile aroma compounds
2002
International audience
Serum proteome profiling of primary breast cancer indicates a specific biomarker profile.
2011
Non-invasive biomarkers for early breast cancer detection are urgently needed, as the risk of recurrent morbidity and mortality is closely related to the stage of the disease at the time of primary surgery. Currently, there are no established clinical biomarkers for breast cancer. Evaluation of protein expression patterns in body fluids using proteomic technologies can be used to discover new biomarkers for the detection of breast cancer. The aim of this study was to identify a biomarker signature identifying primary non-metastatic breast cancer and healthy controls. We screened 91 serum samples including 45 breast cancer patients and 46 healthy women using a proteomic approach. We found 14…
Ultraviolet-induced paramagnetic centers and absorption changes in singlemode Ge-doped optical fibers
2009
We investigated the laser-energy-density dependence of absorption changes and paramagnetic centers induced by a cw Ar+ laser operating at 5.1 eV, in both unloaded and H-2-loaded single mode Ge-doped optical fibers. The induced absorption is measured in the blue and near ultraviolet spectral range by using the 3.1 eV photoluminescence, ascribed to Ge lone pair center (GLPC), as an in situ probe source. We find that the Ge (1) center (GeO4-) is induced upon UV exposure by electron trapping on GeO4 precursors, where the free electrons are most likely produced by ionization of GLPC. Ge (1) is responsible of optical transmission loss of the fiber in the investigated range. Hydrogen loading stron…