Search results for "Volume concentration"
showing 10 items of 43 documents
Detection and quantification of lung cancer biomarkers by a micro-analytical device using a single metal oxide-based gas sensor
2018
International audience; The analysis of exhaled volatile organic compounds (VOCs) related to lung cancer is a very promising wayin medical diagnosis because it is non-invasive and much less expensive than traditional medical analysisused so far. In that sense, a silicon micro-analytical platform consisting of a micro-preconcentrator cou-pled to a silicon spiral gas chromatographic micro-column was built, and a metal oxide-based gas sensorwas used as a miniaturized gas detector. This micro-fabricated device was successfully tested to selec-tively detect low concentrations of VOCs considered as lung cancer biomarkers, within a few minuteseven in presence of high concentrations of water vapor …
Critical temperature modification of low dimensional superconductors by spin doping
2007
Ion implantation of Fe and Mn into Al thin films was used for effective modification of Al superconductive properties. Critical temperature of the transition to superconducting state was found to decrease gradually with implanted Fe concentration. it was found that suppression by Mn implantation much stronger compared to Fe. At low concentrations of implanted ions, suppression of the critical temperature can be described with reasonable accuracy by existing models, while at concentrations above 0.1 at.% a pronounced discrepancy between the models and experiments is observed.
PET Chemistry: An Introduction
2021
One major advantage of radioactivity is its extremely high sensitivity of detection. Regarding the medical applicability of radioactivity, it permits non-invasive in vivo detection of radiolabelled compounds at nano- to picomolar levels. The use of substances at such low concentrations usually precludes a physiological, toxic or immunologic response of the investigated biological system. Consequently, the considered physiological process or system is examined in an unswayed situation. Furthermore, a wide range of substances, even those which are toxic at higher concentrations, become considerable for the development of radiopharmaceuticals and use in nuclear medicine. In contrast to the wid…
Porous silicon photoluminescence biosensor for rapid and sensitive detection of toxins
2017
A rapid and low cost photoluminescence (PL) immunosensor for the determination of low concentrations of Ochratoxin A(OTA) and Aflatoxine B1 (AfB1) has been developed. This biosensor was based on porous silicon (PSi) fabricated by metal-assisted chemical etching (MACE) and modified by antibodies against OTA/AfB1 (anti-OTA/anti-AfB1). Biofunctionalization method of the PSi surface by anti-OTA/ anti-AfB1 was developed. The changes of the PL intensity after interaction of the immobilized anti-OTA/anti-AfB1with OTA/AfB1 antigens were used as biosensor signal, allowing sensitive and selective detection of OTA/AfB1 antigens in BSA solution. The sensitivity of the reported optical biosensor towards…
Pyrrolo[1,2-f]phenanthridines and related non-rigid analogues as antiviral agents.
2002
Abstract The pyrrolo[1,2- f ]phenanthridines 8 – 22 and the corresponding non-rigid analogues 23 – 41 were synthesised and their ability to inhibit the replication of HIV-1 was tested. Only the polycyclic derivatives 10 , 11 , and 13 showed a weak anti -HIV activity, whereas several pyrrolo-phenanthridines ( 8 , 10 , 16 – 18 ) were found to stimulate the multiplication of MT-4 cells at low concentrations. Derivative 10 demonstrated to possess the unique property of stimulating the multiplication of lymphocytes joined to HIV inhibition.
Potential Off-Flavour Compounds from Chloro-Bleaching of Pulp and Chlorodisinfection of Water
1983
Chlorobleaching of pulp is the most important source of organochlorine pollutants in the Finnish aquatic ecosystems. Similar types of pollutants are formed during chlorodisinfection of water. The model compound approach employed in our laboratory has revealed the structures and amounts of pollutants formed and has made the interpretation and assay of individual organochlorine compounds in the environment possible. Tainting of fish near chlorination plants is frequently observed. Especially chlorinated phenols and anisoles (microbial metabolites of the former) are chlorination products which are known to have a strong odour and taste at very low concentrations. Other chlorinated products, wh…
In situ Pesticide Detection in Food Processing by Microwave Transduction Combined with Molecularly Imprinted Polymers
2016
International audience; Since 2005, the microwave transduction coupled with a sensitive material is devoted to gas detection. In this work, we demonstrate the possibility to detect liquid pollutant (pesticide, fungicide) for food-processing industry. The principle is based on the interaction of the pollutant with a sensitive material within a microwave structure. The sensor is submitted to an electromagnetic excitation in wideband frequencies (GHz) and presents a quantitative response to liquid pollutant expositions at low concentration. The retained sensitive material is a molecularly imprinted polymer (MIP) specific to the pesticide targeted in a model wine. The coupling with this materia…
Analytical Methodologies for the Determination of Personal Care Products in Water Samples
2014
Personal-care products (PCPs) could reach the aquatic environment and cause a great impact in the aquatic ecosystem. In this sense, the monitoring of these emerging pollutants in the environment yields valuable information. For this reason, analytical methods to determine PCPs in environmental waters are needed. Due to the low concentration of the PCPs, i.e. ng L−1, sensitive methods are needed. This required sensitivity can be achieved by using sensitive analytical techniques during the measurement step, or by employing enrichment techniques during the sample treatment step. Obviously, the combination of both sensitive analytical techniques and extraction techniques considerably improves t…
Global patterns of polycyclic aromatic hydrocarbons (PAHs) in soil
2007
Abstract Recent findings suggest a higher natural contribution to PAH concentrations in soil than previously thought. I hypothesized that the PAH pattern in soil is dominated by two main types, which are indicative of background conditions on the one side (i.e., by biological and diffuse PAHs) and a strong impact by atmospheric deposition of anthropogenic emissions on the other side. To test this hypothesis, concentrations of 20 PAHs in 225 topsoil samples from 12 geographic regions were evaluated. The Σ20PAHs concentrations ranged between 4.8 and 186,000 μg kg− 1. In soils with low concentrations of Σ20PAHs, naphthalene (NAPH), phenanthrene (PHEN), and perylene (PERY), together defined as …
Analytical techniques for the determination of bismuth in solid environmental samples
2006
Abstract Bismuth is a trace element of the Earth’s crust, which is becoming environmentally significant. Although bismuth has relatively low toxicity, it can form characteristic intracytoplasmatic inclusions. This article illustrates the increasing need for fast pre-treatment techniques and highly sensitive detection methods for accurate measurements of bismuth at extremely low concentrations in solid environmental matrices.