Search results for "Fractionation"
showing 10 items of 332 documents
Analysis of currently used pesticides in fine airborne particulate matter (PM 2.5) by pressurized liquid extraction and liquid chromatography-tandem …
2008
During and after the application of currently used pesticides (CUPs) a significant fraction of applied pesticides can be lost to the air. A confirmatory and rapid procedure has been developed for the determination of four fungicides (carbendazim, thiabendazol, imazalil and bitertanol), three insecticides (imidacloprid, methidathion and pyriproxyfen), one helicide (methiocarb) and one acaricide (hexythiazox) in fine airborne particulate matter (PM 2.5) at trace level. The proposed method includes extraction of PM 2.5-bound pesticides by pressurized liquid extraction (PLE) followed by a direct injection into LC-MS/MS. The main parameters affecting the performance of the electrospray ionizatio…
Fast extraction of cannabinoids in marijuana samples by using hard-cap espresso machines
2018
Abstract A simple, quick and low cost procedure was developed for the extraction of Δ9-tetrahydrocannabinol, cannabidiol, and cannabinol from marijuana samples, based on the use of a hard-cap espresso extraction with 2-propanol. After extraction, cannabinoids were directly determined after appropriate dilution by gas-chromatography-mass spectrometry, reaching a limit of detection from 0.03 to 0.05 mg g−1. Extraction efficiency was evaluated by the comparison of results obtained for seized samples by the proposed method and a reference methodology based on ultrasound-assisted extraction. Moreover, ion mobility was proposed for the rapid and sensitive determination of Δ9-tetrahydrocannabinol …
Fusarium proliferatum: induction and intracellular location of a lipoxygenase
1998
The fungus Fusarium proliferatum was grown in a soya oil- and glucose-supplemented medium. Induction of lipoxygenase activity (13-fold) in an extract of Fusarium biomass has been observed at day four on soya oil culture medium. A band at 232 kDa was detected using a specific lipoxygenase stain combined with native PAGE. The method of fungal homogenate obtained has been checked via subcellular marker enzymes activities: succinate dehydrogenase (SDH) for mitochondrial fraction and NADH-cytochrome C reductase (NADH-cyt. C) for the microsomal fraction. Protoplasts production and disintegration followed by subcellular fractionation using differential centrifugation was the best method to recover…
Selected Secondary Plant Metabolites for Cancer Therapy
2015
Secondary plant metabolites reveal numerous biological activities making them attractive as resource for drug development of human diseases. As the majority of cancer drugs clinically established during the past half century is derived from nature, cancer researchers worldwide try to identify novel natural products as lead compounds for cancer therapy. Natural products are considered as promising cancer therapeutics, either as single agents or in combination protocols, to enhance the antitumor activity of additional therapeutic modalities. Most natural compounds exert pleotrophic effects and modulate various signal transduction pathways. A better understanding of the complex mechanisms of a…
Assisting Electrophysiological Substrate Quantification in Atrial Fibrillation Ablation
2019
[EN] Catheter ablation (CA) is the most popular treatment of atrial fibrillation (AF) with good results in paroxysmal AF, while its efficiency is significantly reduced in persistent AF. With the equipment used for CA strongly depending on electro-gram (EGM) fractionation quantification, the use of a reliable fractionation estimator is crucial to reduce the high recurrence rates in persistent AF. This work introduces a non-linear EGM fractionation quantification technique, which is based on coarse-grained correlation dimension (CGCD) computed over epochs of 1 second. Recordings were firstly normalized, denoised and lowpass filtered. The final CGCD value was calculated by the median CGCD valu…
Increasing voltage gradient electrophoresis of DNA
2007
We developed a method which allows electrophoretic fractionation of DNA in an agarose matrix according to an increasing current gradient, using a previously designed [R. Barbieri, V. Izzo, M.A. Costa, G. Giudice, G. Duro, Anal. Biochem. 212 (1993) 168; M.R. Asaro, V. Izzo, R. Barbieri, J. Chromatogr. A 855 (1999) 723] voltage gradient apparatus. This method allows the separation of different DNA fragments by increasing the distances of the components fractionated in the gel, revealing small differences in the length of different DNA components.
Analysis of fumonisins B1, B2 and B3 in corn-based baby food by pressurized liquid extraction and liquid chromatography/tandem mass spectrometry
2008
A sensitive and reliable method using pressurized liquid extraction (PLE) and liquid chromatography (LC)/electrospray ionization (ESI) tandem mass spectrometry with a triple quadrupole (QqQ) analyzer has been developed for the analysis of fumonisin B(1) (FB(1)), fumonisin B(2) (FB(2)) and fumonisin B(3) (FB(3)) in corn-based baby foods. Influence of several extraction parameters that affect PLE efficiency such as temperature, pressure, solvent extraction, number of cycles and dispersant/clean-up agents were studied. The selected PLE operating method was: 3g of sample was packed into 11 ml stainless-steel cell and fumonisins were extracted with methanol at 40 degrees C, 34 atm in one cycle o…
Mitochondrial localization and temporal expression of the Drosophila melanogaster DnaJ homologous tumor suppressor Tid50
1998
The Drosophila melanogaster tumor suppressor gene lethal(2)tumorous imaginal discs (tid) was identified as a homolog of all dnaJ-like genes known to date which have been well preserved in evolution. Homozygous D. melanogaster l(2)tid mutants l(2)tid1, l(2)tid2 and l(2)tid3 are characterized by neoplastic transformation of the adult integumental primordia, the imaginal discs, and the death at the time of puparium formation. The first part of this study is concerned with the identification and subcellular localization of the l(2)tid-encoded protein, Tid50. The second part examines its tissue specific expression during wild-type development and in tumorous imaginal discs. To specify the functi…
Subcellular fractionation of tissue culture cells.
2003
Cell fractionation techniques include some of the most important and widely used analytical tools in cell and molecular biology, and are essential for the development of cell-free assays that reconstitute complicated cellular processes. In addition to simple gradient systems, this unit discusses the immuno-purification of organelles, in particular endosomes. As antigens, purification can be achieved using endogenous or ectopically expressed proteins, provided that appropriate antibodies are available. Alternatively, tagged proteins can be used, when combined with anti-tag antibodies. Now that sequencing of the genomes of several organisms has been completed, biochemical strategies, and in p…
Effects of solid–liquid separation on recovering residual methane and nitrogen from digested dairy cow manure
2006
The feasibility of optimizing methane and nitrogen recovery of samples obtained from farm biogas digester (35 degrees C) and post-storage tank (where digested material is stored for 9-12 months) was studied by separating the materials into different fractions using 2, 1, 0.5 and 0.25 mm sieves. Mass-balances revealed that digested material mainly consists of0.25 mm (60-69%) and2 mm (18-27%) fractions, while fractions between 2 and 0.2 mm made the rest. Incubation of solid fractions0.25 mm of digester material at 35 degrees C resulted in specific methane yields of 0.060-0.085 m(3)kg(-1) volatile solids (VS) during initial 30-50 d and 0.16-0.18 m(3)kg(-1)VS at the end of 340 d incubation. Sim…