The analytical method developed is based on HPLC-MS/MS to simultanous determine Progesterone,Boldenone and Trenbolone in Chicken,Beef and Pork meats.The sample is freeze drying reduced in powder and a Methanol-Acetate...The analytical method developed is based on HPLC-MS/MS to simultanous determine Progesterone,Boldenone and Trenbolone in Chicken,Beef and Pork meats.The sample is freeze drying reduced in powder and a Methanol-Acetate Buffer (pH=5.2) solution is added in order to perform the extraction and sonicated with a solution prior to deconjugation using β-glucosidase.The sample is purified using C18 and SiOH solid phase extraction (SPE) cartridge prior to analyze on reversed phase with a elution gradient performed on Agilent C18 coupled with a HPLC-MS/MS.The detection Limit is respectively 0.11,0.17 and 0.02 μg/kg for Trenbolone,Boldenone and Progesterone with a ratio Signal/Noise>3 in the 3 different kind of meat.The quantification was based on the peak area and overall recoveries of synthetic growth hormones were 62%-99%.展开更多
The erosion of silver contacts due to break arcs with length proportional to time and of variable duration has been measured by weighing the contacts following 5000 openings at a constant current equal to 40 A.The exp...The erosion of silver contacts due to break arcs with length proportional to time and of variable duration has been measured by weighing the contacts following 5000 openings at a constant current equal to 40 A.The experimental results show that,for arc durations shorter than 60 μs,the transfer of metal from the anode to the cathode occurs,but after passing this stage,when the two electrodes are separated by greater distances,each will display erosion.This is the result of the diffusion of material outside the space between the two electrodes.In order to interpret these results,we have applied a classical model of the physical phenomena occurring at the root of the arc.Analysis of the experimental results shows that for an arc duration of less than15 μs,no distinct cathode root is seen to exist,but beyond this,several spots appear gradually on the cathode for arc duration up to 50 μs,after which they merge into a single spot.The comparison between experiment results and theoretical interpretation is reasonable up to 60 μs.展开更多
The lancehead (Bothrops lanceolatus) is a poisonous snake endemic to Martinique, an island in the Lesser Antilles arc. Today, this snake is on the verge of extinction. The recorded number of snakes killed yearly betwe...The lancehead (Bothrops lanceolatus) is a poisonous snake endemic to Martinique, an island in the Lesser Antilles arc. Today, this snake is on the verge of extinction. The recorded number of snakes killed yearly between 1970 and 2002 decreased by 97%. Despite the production of an antivenom in 1993, the local authorities set up a financial reward to encourage the eradication of lancehead snakes. Today the local population still perceives the snake as a threat, due to its fatal venom and its fierce behaviour. The case study of the lancehead in Martinique highlights the need to develop integrated strategies to conserve species of poisonous snakes on densely populated islands. This requires innovative, cross-sectoral strategies that involve decision-makers working along with multi-disciplinary scientists. Approaching the complexity of ecosystems through the socio-ecological prism implies, conversely, linking up the domains of science and technology, life and environmental sciences, and human and social sciences, through interactions based on sharing common展开更多
A new Zn(II) complex with the monodentate ligand methyl-(2-pyridin-2-yl-ethyl)-ammonium, ZnCl3C8H13N2, has been prepared and characterized by single crystal X-ray diffraction. The Zn(II) ion is tetracoordinated by one...A new Zn(II) complex with the monodentate ligand methyl-(2-pyridin-2-yl-ethyl)-ammonium, ZnCl3C8H13N2, has been prepared and characterized by single crystal X-ray diffraction. The Zn(II) ion is tetracoordinated by one nitrogen atom of organic ligand and three chlorine ligands. In the atomic arrangement, the ZnNCl3 tetrahedra form corrugated chains extending along the b-axis. The organic entities are located between these chains through N-H···Cl, C-H···Cl and C-H···N hydrogen bonds to form layers parallel to (b, c) plan. Among these hydrogen bonds two are bifurcated.展开更多
文摘The analytical method developed is based on HPLC-MS/MS to simultanous determine Progesterone,Boldenone and Trenbolone in Chicken,Beef and Pork meats.The sample is freeze drying reduced in powder and a Methanol-Acetate Buffer (pH=5.2) solution is added in order to perform the extraction and sonicated with a solution prior to deconjugation using β-glucosidase.The sample is purified using C18 and SiOH solid phase extraction (SPE) cartridge prior to analyze on reversed phase with a elution gradient performed on Agilent C18 coupled with a HPLC-MS/MS.The detection Limit is respectively 0.11,0.17 and 0.02 μg/kg for Trenbolone,Boldenone and Progesterone with a ratio Signal/Noise>3 in the 3 different kind of meat.The quantification was based on the peak area and overall recoveries of synthetic growth hormones were 62%-99%.
文摘The erosion of silver contacts due to break arcs with length proportional to time and of variable duration has been measured by weighing the contacts following 5000 openings at a constant current equal to 40 A.The experimental results show that,for arc durations shorter than 60 μs,the transfer of metal from the anode to the cathode occurs,but after passing this stage,when the two electrodes are separated by greater distances,each will display erosion.This is the result of the diffusion of material outside the space between the two electrodes.In order to interpret these results,we have applied a classical model of the physical phenomena occurring at the root of the arc.Analysis of the experimental results shows that for an arc duration of less than15 μs,no distinct cathode root is seen to exist,but beyond this,several spots appear gradually on the cathode for arc duration up to 50 μs,after which they merge into a single spot.The comparison between experiment results and theoretical interpretation is reasonable up to 60 μs.
基金the support of“Investissements d’Avenir”of the French National Agency for Research(CEBA,ref.ANR-10-LABX-25-01).
文摘The lancehead (Bothrops lanceolatus) is a poisonous snake endemic to Martinique, an island in the Lesser Antilles arc. Today, this snake is on the verge of extinction. The recorded number of snakes killed yearly between 1970 and 2002 decreased by 97%. Despite the production of an antivenom in 1993, the local authorities set up a financial reward to encourage the eradication of lancehead snakes. Today the local population still perceives the snake as a threat, due to its fatal venom and its fierce behaviour. The case study of the lancehead in Martinique highlights the need to develop integrated strategies to conserve species of poisonous snakes on densely populated islands. This requires innovative, cross-sectoral strategies that involve decision-makers working along with multi-disciplinary scientists. Approaching the complexity of ecosystems through the socio-ecological prism implies, conversely, linking up the domains of science and technology, life and environmental sciences, and human and social sciences, through interactions based on sharing common
文摘A new Zn(II) complex with the monodentate ligand methyl-(2-pyridin-2-yl-ethyl)-ammonium, ZnCl3C8H13N2, has been prepared and characterized by single crystal X-ray diffraction. The Zn(II) ion is tetracoordinated by one nitrogen atom of organic ligand and three chlorine ligands. In the atomic arrangement, the ZnNCl3 tetrahedra form corrugated chains extending along the b-axis. The organic entities are located between these chains through N-H···Cl, C-H···Cl and C-H···N hydrogen bonds to form layers parallel to (b, c) plan. Among these hydrogen bonds two are bifurcated.
