Electromembrane extraction (EME) is a miniaturized technique in which charged molecules are extracted from biological samples, through a porous membrane, into an acceptor solution. This process ...occurs in the presence of an electric field that enables increased analyte recovery in short extraction times. Studies are being carried out to establish recommended extraction conditions for different groups of compounds based on their physicochemical properties. In this work, pre-established generic liquid membranes for the extraction of basic compounds were tested using synthetic cathinones within a wide log P range as basic model analytes. First, recommended organic solvents for the chosen analytes were evaluated in terms of recovery. The best candidates were included in an optimization study with other relevant EME conditions (voltage, extraction time, and agitation rate). All analyses were performed using a UPLC-MS/MS with the multiple reaction monitoring mode. 2-Undecanone was chosen as the liquid membrane providing the best extraction efficiency in combination with 40 V, 35 min, and 725 rpm. Validation showed r2 > 0.99 in the 1–500 ng/mL range, accuracy of ±12%, imprecision of ≤19%, 1 ng/mL as limit of quantitation, 0.1–0.5 ng/mL as limit of detection, matrix effect 97–118%, and recovery 63–110%. Among the generic liquid membranes studied in this work, 2-Undecanone was the best choice for the target basic analytes. High recoveries and low matrix effects were achieved, thus demonstrating the applicability of recommended generic liquid membranes in the 96-well plate setup and with whole blood samples. Our findings contribute to further establishing EME as an actual sample preparation technique for routine analyses that could be further explored in a commercial format.
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•The performance of EME on a prototype 96-well plate setup was studied.•The applicability of generic SLM for basic compounds was evaluated.•Synthetic cathinones were the model basic analytes extracted from whole blood.•NPOE+6 MC:Thy and 2-Undecanone were the best SLM for the target compounds.•Further consolidating EME as a green and efficient technique for routine analyses.
Ultraviolet and blue light were obtained by nonlinear frequency conversion in a random laser (RL) based on Nd0.10Y0.90Al3(BO3)4 nanocrystalline powder. RL operation at 1062 nm, due to the (4)F3/2 → ...(4)I11/2 transition of neodymium ions (Nd(3+)), was achieved by exciting the Nd(3+) with a tunable beam from 680 to 920 nm covering the ground state absorption transitions to the (4)F9/2, ((4)F7/2,(4)S3/2), ((4)F5/2,(2)H9/2), and (4)F3/2 states. Light from 340 to 460 nm was obtained via the second-harmonic generation of the excitation beam while tunable blue light, from 417 to 486 nm, was generated by self-sum-frequency mixing between the excitation beam and the RL emission.
•Synthesis of neodymium doped nanoparticles for random lasers.•Observation of random laser emission in the powders for Nd3+ concentration ranging from 0.05 to 1.00%.•Observation of ...self-second-harmonic and self-sum-frequency generations, and second-harmonic of the excitation beam.•Multi-wavelength emission based on a unique material.•Enhancement of the random laser performance and decrease of the second-order nonlinear response for large Nd3+ concentration.
Random Laser emission at 1.06μm, self-second-harmonic generation at 0.53μm and self-sum-frequency generation at 0.46μm were investigated in NdxY1.00−xAl3(BO3)4 nanocrystalline powders, for 0.05⩽x⩽1.00, excited by a pulsed laser operating at 808nm, focusing on the interplay between the RL performance and the second-order nonlinear processes. The RL performance, characterized by a figure-of-merit relating the laser slope efficiency and the excitation pulse energy threshold, improved as x increased up to 1.00 while the efficiency of the self-frequency conversion processes reduced for increasing x because of distortions introduced in the crystalline structure of the grains. The RL wavelength was also dependent on the Nd3+ concentration and presented a redshift from 1061.9nm to 1063.5nm for increasing values of x.
Random Laser emission at 1.06 mu m, self-second-harmonic generation at 0.53 mu m and self-sum-frequency generation at 0.46 mu m were investigated in Nd sub(x)Y sub(1.00-) sub(x)Al sub(3)(BO sub(3)) ...sub(4) nanocrystalline powders, for 0.05 el x el 1.00, excited by a pulsed laser operating at 808 nm, focusing on the interplay between the RL performance and the second-order nonlinear processes. The RL performance, characterized by a figure-of-merit relating the laser slope efficiency and the excitation pulse energy threshold, improved as x increased up to 1.00 while the efficiency of the self-frequency conversion processes reduced for increasing x because of distortions introduced in the crystalline structure of the grains. The RL wavelength was also dependent on the Nd super(3+) concentration and presented a redshift from 1061.9 nm to 1063.5 nm for increasing values of x.
The conversion of solar energy into hydrogen fuel by splitting water into photoelectrochemical cells (PEC) is an appealing strategy to store energy and minimize the extensive use of fossil fuels. The ...key requirement for efficient water splitting is producing a large band bending (photovoltage) at the semiconductor to improve the separation of the photogenerated charge carriers. Therefore, an attractive method consists in creating internal electrical fields inside the PEC to render more favorable band bending for water splitting. Coupling ferroelectric materials exhibiting spontaneous polarization with visible light photoactive semiconductors can be a likely approach to getting higher photovoltage outputs. The spontaneous electric polarization tends to promote the desirable separation of photogenerated electron- hole pairs and can produce photovoltages higher than that obtained from a conventional p-n heterojunction. Herein, we demonstrate that a hole inversion layer induced by a ferroelectric Bi4V2O11 perovskite at the n-type BiVO4 interface creates a virtual p-n junction with high photovoltage, which is suitable for water splitting. The photovoltage output can be boosted by changing the polarization by doping the ferroelectric material with tungsten in order to produce the relatively large photovoltage of 1.39 V, decreasing the surface recombination and enhancing the photocurrent as much as 180%.
The use of Nd x Y 1.00-x Al 3 (BO 3 ) 4 nanocrystalline powders as Random Lasers allowed observation of self-second-harmonic and self-sum-frequency generation of tunable UV-blue light. An optical ...thermometer operation based on a two-color random laser was also demonstrated.
The influenza is a common viral infection that can be fatal, especially in high-risk groups such as children, pregnant women, elderly, and immune-deficient individuals. Vaccination is the most ...efficient approach to prevent the spreading of viral infection and promote individual and public health. In contrast, exposure to environmental pollutants such as cigarette smoke reduces the efficacy of vaccination. We investigated whether chronic exposure to hydroquinone (HQ), the most abundant compound of the tobacco particulate phase, could impair the adaptive immune responses elicited by influenza vaccination. For this, adult male C57BL/6 mice were daily exposed to either nebulized HQ or PBS for 1 h for a total of eight weeks. At weeks 6 and 8, the mice were primed and boosted with the trivalent influenza vaccine via IM respectively. Although the HQ exposure did not alter the body weight of the mice and the biochemical and hematological parameters, the pollutant increased the oxidative stress in splenocytes of immunized animals, modified the morphology of spleen follicles, and augmented the size of their lymph nodes. The lymphoid organs of HQ-exposed mice presented a similar number of vaccine-specific IgG-secreting cells, titers of vaccine-specific total IgG, and respective subclasses. Transcriptome studies with HQ, benzene, or cigarette smoke exposure were also analyzed. The genes up-regulated upon pollutant exposure were associated with neutrophil migration and were shown to be co-expressed with antibody-secreting cell genes. Therefore, these findings suggest that HQ exposure may trigger an immune-compensatory mechanism that enhances the humoral responses induced by influenza vaccination.
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•Repeated in vivo HQ exposure caused oxidative stress in murine splenocytes.•HQ exposure disorganized the lymphoid organ structure post influenza vaccination.•HQ exposure did not harm the influenza vaccine-derived cellular and humoral responses.•Exposure to benzene, cigarette smoke, or HQ changed the expression of immune genes.•Neutrophil and B-cell genes were co-expressed upon in vivo HQ and benzene exposure.
Divination and magic: powers in Yemen Smith, G Rex; Varisco, Daniel Martin; Peskes, Esther ...
Quaderni di studi arabi,
01/1995, Letnik:
13
Journal Article
1687-1928
Nombre de vues du document : 445
Date de numérisation : 2011
Note : Edouard Dantan est le fils d’Antoine Laurent Dantan et neveu de Jean-Pierre Dantan ; François-Joseph Duret est le père de ...Francisque-Joseph Duret ; John II Flaxman est le fils du sculpteur John Flaxman, décédé vers 1795
Note de contenu : Contient un portrait photographique de Pierre-Jean David d’Angers et une estampe de sa statue Sainte Cécile présentée au Salon de 1834 ; Contient 2 portraits photographiques d’Antoine Etex
Note complémentaire : Contient une lithographie de Marie-Alexandre Alophe représentant Francisque-Joseph Duret dans Galerie de la Presse, de la Littérature et des Beaux-Arts
Documents en rapport : Original de la Lettre autographe signée d'Antoine Etex à monsieur Guiegesse, 16 septembre 1860
Documents en rapport : Lithographie de Marie-Alexandre Alophe représentant le sculpteur Francisque-Joseph Duret
Partenariats : Document numérisé grâce au mécénat de la Société BIC
Langue du document : Français
Langue du document : Anglais
Langue du document : Italien
Lieu de publication : S.l.
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