Hamada A.S.,University of Oulu |
Hamada A.S.,Suez Canal University |
Haggag F.M.,Advanced Technology Corporation ATC |
Porter D.A.,University of Oulu
Materials Science and Engineering A | Year: 2012
The applicability of the automated ball indentation (ABI) technique for non-destructively determining the yield strength and flow properties of a high-manganese twinning-induced plasticity steel has been explored for different grain structures. True stress-true plastic strain curves derived from the ABI measurements agreed closely with those from conventional uniaxial tensile tests showing that the technique can be used to determine the yield strength, true-stress versus true-plastic strain curve, the strength coefficient and the strain hardening exponent of the steel concerned. © 2012 Elsevier B.V.
Martin G.,University of Liege |
Mansion F.,University of Liege |
Houbart V.,University of Liege |
Paquet P.,Dermathopathology |
And 5 more authors.
Talanta | Year: 2011
The incidence of malignant melanona has increased over the past decades, particularly in Caucasian population. This disease presents defavourable prognosis in terms of survey, especially when detection occurs at the metastatic phase. Reliable analytical methods for biomarker determination are thus an interesting tool in pathology detection and follow-up. In this context, a method using SPE-LC-ESI-MS-MS for the determination of 5-S-cysteinyldopa (5-SCD) in human plasma was optimized. The presence of matrix effect was investigated in details while 5-SCD stability was studied according to FDA requirements for the validation of bioanalytical methods. Pre-study and in-study validations of the entire method were then successfully performed by applying the approach based on total measurement error and accuracy profiles over a concentration ranges from 1.6 to 200 ng/ml. Good results with respect to accuracy, trueness and precision were obtained. The maximum risk of observing future measurements falling outside the acceptance limits during routine analysis was also estimated. © 2011 Elsevier B.V. All rights reserved.
Development and validation of a nonaqueous capillary electrophoretic method for the enantiomeric purity determination of a synthetic intermediate of new 3,4-dihydro-2,2-dimethyl-2H-1-benzopyrans using a single-isomer anionic cyclodextrin derivative and an ionic liquid
Rousseau A.,University of Liege |
Florence X.,University of Liege |
Pirotte B.,University of Liege |
Varenne A.,Chimie Paristech |
And 6 more authors.
Journal of Chromatography A | Year: 2010
The enantiomeric purity determination of a synthetic intermediate of new 3,4-dihydro-2,2-dimethyl-2H-1-benzopyrans, i.e. 4-amino-2,2-dimethyl-6-ethoxycarbonylamino-3,4-dihydro-2H-1-benzopyran, was successfully carried out using an anionic cyclodextrin (CD) derivative combined with a chiral ionic liquid (IL). In order to obtain high resolution and efficiency values, the addition of a chiral IL, i.e. ethylcholine bis(trifluoromethylsulfonyl)imide (EtChol NTf2), to the background electrolyte containing heptakis(2,3-di-O-methyl-6-O-sulfo)-β-CD (HDMS-β-CD) was found to be essential. A simultaneous increase in separation selectivity and enantioresolution seems to indicate a synergistic effect of HDMS-β-CD and EtChol NTf2. The best enantioseparation of the key intermediate was achieved using a methanolic solution of 0.75M formic acid, 10mM ammonium formate, 1.5mM HDMS-β-CD and 5mM EtChol NTf2. Levamisole was selected as internal standard. The optimized conditions allowed the determination of 0.1% of each enantiomer in the presence of its stereoisomer using the method of standard additions. The NACE method was then fully validated with respect to selectivity, response function, trueness, precision, accuracy, linearity and limits of detection and quantification. © 2010 Elsevier B.V.
Constant-Urban C.,The Interdisciplinary Center |
Charif M.,University of Liege |
Goffin E.,The Interdisciplinary Center |
Van Heugen J.-C.,Advanced Technology Corporation ATC |
And 7 more authors.
Bioorganic and Medicinal Chemistry Letters | Year: 2013
The present work aims at identifying new ion channel modulators able to target mitochondrial ATP-sensitive potassium channels (mitoKATP channels). An innovative approach should consist in fixing a cationic and hydrophobic triphenylphosphonium fragment on the structure of known K ATP channel openers. Such phosphonium salts are expected to cross the biological membranes and to accumulate into mitochondria. Previous works revealed that the presence of an (R)-1-hydroxy-2-propylamino chain at the 3-position of 4H-1,2,4-benzothiadiazine 1,1-dioxides KATP channel openers increased, in most cases, the selectivity towards the pancreatic-type (SUR1/Kir6.2) KATP channel. In order to target cardiac mitoK ATP channels, we decided to introduce a triphenylphosphonium group through an ester link on the SUR1-selective (R)-7-chloro-3-(1-hydroxy-2-propyl) amino-4H-1,2,4-benzothiadiazine 1,1-dioxide. The new compounds were found to preserve an inhibitory activity on insulin secretion (SUR1-type KATP channel openers) while no clear demonstration of an impact on mitochondria from cardiomyocytes (measurement of oxygen consumption, respiratory parameters and ATP production on H9C2 cells) was observed. However, the most active (inhibition of insulin release) compound 17 was found to penetrate the cardiac cells and to reach mitochondria. © 2013 Elsevier Ltd. All rights reserved.
Rousseau A.,University of Liege |
Gillotin F.,Advanced Technology Corporation ATC |
Chiap P.,Advanced Technology Corporation ATC |
Bodoki E.,Universitatea Of Medicina Si Farmacie |
And 3 more authors.
Journal of Pharmaceutical and Biomedical Analysis | Year: 2011
The enantioseparation of 10 basic drugs was evaluated in NACE systems using heptakis(2-O-methyl-3-O-acetyl-6-O-sulfo)-β-CD (HMAS-β-CD). For this purpose, a D-optimal design with 21 experimental points was applied. Four antifungal agents (econazole, isoconazole, miconazole, sulconazole), three local anesthetics (bupivacaine, mepivacaine and prilocaine), two sympathomimetics (salbutamol and terbutaline) and one β-blocker (carvedilol) were selected as basic model analytes. The influence on the enantiomeric resolution of anionic CD and BGE anion concentrations as well as the BGE anion nature was investigated. For all studied analytes, the enantiomeric resolution was shown to be significantly influenced by the CD concentration. Based on the observed results, a generic NACE system was recommended, namely 20mM HMAS-β-CD and 10mM ammonium camphorSO3- in methanol acidified with 0.75M formic acid. Moreover, this NACE system was compared to previous conditions with heptakis(2,3-di-O-methyl-6-O-sulfo)-β-CD (HDMS-β-CD) or heptakis(2,3-di-O-acetyl-6-O-sulfo)-β-CD (HDAS-β-CD). Finally, two generic systems using either HDAS-β-CD or HMAS-β-CD were proposed and evaluated for the enantioseparation of ketamine and norketamine after incubation of ketamine in phenobarbital-induced male rat liver microsomes systems. © 2010 Elsevier B.V.