Search results for "Static"
showing 10 items of 1528 documents
2020
Biomolecules, and particularly proteins, bind on nanoparticle (NP) surfaces to form the so-called protein corona. It is accepted that the corona drives the biological distribution and toxicity of NPs. Here, the corona composition and structure were studied using silica nanoparticles (SiNPs) of different sizes interacting with soluble yeast protein extracts. Adsorption isotherms showed that the amount of adsorbed proteins varied greatly upon NP size with large NPs having more adsorbed proteins per surface unit. The protein corona composition was studied using a large-scale label-free proteomic approach, combined with statistical and regression analyses. Most of the proteins adsorbed on the N…
Optical Absorption of Zinc Selenide Doped with Cobalt (Zn1-xCoxSe) under Hydrostatic Pressure
2000
Optical absorption of the diluted magnetic semiconductor Zn 1-x Co x Se (x = 0.02) has been measured at room temperature under hydrostatic pressure up to 14 GPa in a membrane diamond-anvil cell. We found two absorption features: (i) an absorption structure in the energy range 1.5 to 1.8 eV, with a negligible pressure shift (i.e. (0.45 ± 0.05) meV/GPa) which we have identified as the Co 2+ (3d 7 ) internal transition 4 A 2 (F) → 4 T 1 (P) and (ii) an onset in the energy range 2 to 2.7 eV which redshifts with pressure (dE/dP = (-8.1 ± 0.6) meV/GPa). We have attributed such absorption edge to charge transfer between the ZnSe valence band and the Co 2+ (3d 7 ) levels. On the assumption that tho…
Determination of aminoglycoside and macrolide antibiotics in meat by pressurized liquid extraction and LC-ESI-MS
2010
A simple method for the simultaneous determination of dihydrostreptomycin, spectinomycin, spiramycin, streptomycin, tilmicosin, and tylosin in meat has been developed using pressurized liquid extraction and LC-triple quadrupole MS (LC-ESI-MS/MS). The pressurized liquid extraction operational parameters were optimized and no protein precipitating and fat removing steps were required. A gradient HPLC separation was developed with ion-pair mobile phases consisting of aqueous 1 mM heptafluorobutyric acid water and methanol. Protonated molecules were used as precursor ions for CID. Data acquisition under MS/MS was achieved by applying multiple reaction monitoring of three fragment ion transition…
Optical absorption of zinc selenide doped with cobalt (Zn1−xCoxSe) under hydrostatic pressure
2000
Abstract The optical absorption of the diluted magnetic semiconductor Zn1−xCOxSe (x = 0.02) has been measured at room temperature under hydrostatic pressure up to 14GPa in a membrane diamond-anvil cell. We found two absorption features: (i) an absorption structure in the energy range 1.6−1.8eV, with a negligible pressure shift (i.e., 0.45 ± 0.05 meV/GPa) which we have identified as the Co2+(3d7) internal transition 4A2(F)→+4T1(P) and (ii) an onset in the energy range 2−2.7eV which redshifts with pressure (−8.1±0.6meV/GPa). We have attributed such absorption edge to charge transfer between the ZnSe valence band and the Co2+(3d7) levels.
Interaction Between Osmotic and Hydrostatic Pressure in Yeast Inactivation
1999
The protective effect of an osmotic perturbation on high-pressure inactivation has been investigated using a yeast strain:Saccharomyces cerevisiae. Osmotic shocks have been carried out with binary medium (glycerol/sorbitol and water) with or without glucose. Variations of osmotic level, osmotic shift kinetics and time between osmotic and hydrostatic treatment (350 MPa/10 min) have allowed the characterization of cell baroprotection. Two different cumulative baroprotection effects have been distinguished: one conferred by the solute on biological structures and the other related to the osmotic stress, cell volume variations and stress metabolism response (HSP, trehalose). These experiments h…
Differences in Chromatic Sensitivity Estimated Using Static and Dynamic Colour Stimuli
2017
Abstract The current study reports on a novel computerised colour vision test employing static and dynamic stimuli. The aim of the study was to assess if static and dynamic stimuli result in comparable chromatic discrimination thresholds when participant’s age is taken into account. Participants (n = 20) were 21 to 77 years old, had normal colour vision and no history of any eye disease. They all participated in two sessions estimating chromatic sensitivity with static and dynamic stimuli, respectively, with six directions in colour space varying either along the red-green (RG) or yellow- blue (YB) directions. We found no significant differences in chromatic thresholds along a tritan axis o…
Low-Head Hydropower for Energy Recovery in Wastewater Systems
2022
Hydraulic turbines for energy recovery in wastewater treatment plants, with relatively large discharges values and small head jumps, are usually screw Archimedes or Kaplan types. In the specific case of a small head jump (about 3 m) underlying a rectangular weir in the major Palermo (Italy) water treatment plant, a traditional Kaplan solution is compared with two other new proposals: a Hydrostatic Pressure Machine (HPM) located at the upstream channel and a cross-flow turbine (CFT) located in a specific underground room downstream of the same channel. The fluid mechanical formulations of the flow through these turbines are analyzed and the characteristic parameters are stated. Numerical ana…
Crystal structure, Hirshfeld surface analysis and DFT studies of (E)-1-(4-bromophenyl)-3-(3-fluorophenyl)prop-2-en-1-one
2018
The title halogenated organic chalcone was prepared by a Claisen–Schmidt condensation reaction. A Hirshfeld surface analysis was carried out to reveal the percentage contributions of the intermolecular interactions. A theoretical study was performed using the density functional theory (DFT) at B3LYP with the 6–311 G++(d,p) basis set level to compare with the experimental results of the X-ray analysis and UV–vis absorption analysis in term of the geometrical parameters, HOMO-LUMO energy gap and charge distributions.
Crystal structure, Hirshfeld surface analysis and electrostatic potential study of naturally occurring cassane-type diterpenoid Pulcherrimin C monohy…
2019
Single crystal X-ray diffraction analysis and Hirshfeld surface analysis of the title compound were carried out to analyse quantitatively the intermolecular interactions involved in the crystal packing. The electrostatic potential surface was generated over the Hirshfeld surface to visualize the potential active sites.