987 research outputs found
A High-Resolution Combined Scanning Laser- and Widefield Polarizing Microscope for Imaging at Temperatures from 4 K to 300 K
Polarized light microscopy, as a contrast-enhancing technique for optically
anisotropic materials, is a method well suited for the investigation of a wide
variety of effects in solid-state physics, as for example birefringence in
crystals or the magneto-optical Kerr effect (MOKE). We present a microscopy
setup that combines a widefield microscope and a confocal scanning laser
microscope with polarization-sensitive detectors. By using a high numerical
aperture objective, a spatial resolution of about 240 nm at a wavelength of 405
nm is achieved. The sample is mounted on a He continuous flow cryostat
providing a temperature range between 4 K and 300 K, and electromagnets are
used to apply magnetic fields of up to 800 mT with variable in-plane
orientation and 20 mT with out-of-plane orientation. Typical applications of
the polarizing microscope are the imaging of the in-plane and out-of-plane
magnetization via the longitudinal and polar MOKE, imaging of magnetic flux
structures in superconductors covered with a magneto-optical indicator film via
Faraday effect or imaging of structural features, such as twin-walls in
tetragonal SrTiO. The scanning laser microscope furthermore offers the
possibility to gain local information on electric transport properties of a
sample by detecting the beam-induced voltage change across a current-biased
sample. This combination of magnetic, structural and electric imaging
capabilities makes the microscope a viable tool for research in the fields of
oxide electronics, spintronics, magnetism and superconductivity.Comment: 14 pages, 11 figures. The following article has been accepted by
Review of Scientific Instruments. After it is published, it will be found at
http://aip.scitation.org/journal/rs
Cyclometallated Platinum(II) Complexes Featuring an Unusual, C^NâCoordinating Pyridylâpyridylidene Ligand and LâX Coligands: Synthesis, Structures and Dual Luminescence Behavior
Thanks to an unusual protodemethylation reaction, a series of luminescent cyclometallated platinum(II) complexes can be prepared, which incorporate a rare NC-chelating, pyridyl-pyridylidene ligand, in combination with OO-coordinating acetylacetonate (acac) or NO-coordinating 2-picolinate (pic) or 8-hydroxyquinolate. The acac and pic complexes show unusual dual emission in a frozen glass.A series of cyclometallated platinum(II) complexes incorporating a rare, N^C-chelating, pyridyl-pyridylidene ligand are described, in which the coordination sphere is completed by two chlorides or an LâX co-ligand, namely OâO-coordinating acetylacetonate (acac), or N^O-coordinating 2-picolinate (pic) or 8-hydroxyquinolinate. The acac and pic complexes have been structurally characterized in the solid state by single-crystal X-ray diffraction. These two complexes display red phosphorescence in the solid state at room temperature. In a frozen glass at 77â
K, all four complexes show two broad emission bands that span much of the visible spectrum, apparently from two unequilibrated excited states
A method to obtain disinfected Globodera infective juveniles directly from cysts
Les systÚmes d'inoculation in vitro sont des outils performants et précis pour l'étude des interactions plantes-nématodes. L'obtention de juvéniles stériles est une étape cruciale pour la plupart de ces systÚmes. La majorité des protocoles publiés comprennent une désinfection des juvéniles, ce qui conduit à une mortalité élevée. Nous décrivons ici une nouvelle méthode pour désinfecter, rapidement, facilement, et à faible coût des nématodes du genre #Globodera$, en partant de kystes. La mortalité des juvéniles désinfectés est faible (entre 10 et 40% au maximum). Les juvéniles stérilisés infestent les racines de pomme de terre cultivées in vitro et s'y développent normalement. (Résumé d'auteur
Stress Conditions Induced by Carvacrol and Cinnamaldehyde on Acinetobacter baumannii
Acinetobacter baumannii has emerged as a major cause of nosocomial infections. The ability of A. baumannii to display various resistance mechanisms against antibiotics has transformed it into a successful nosocomial pathogen. The limited number of antibiotics in development and the disengagement of the pharmaceutical industry have prompted the development of innovative strategies. One of these strategies is the use of essential oils, especially aromatic compounds that are potent antibacterial molecules. Among them, the combination of carvacrol and cinnamaldehyde has already demonstrated antibacterial efficacy against A. baumannii. The aim of this study was to determine the biological effects of these two compounds in A. baumannii, describing their effect on the rRNA and gene regulation under environmental stress conditions. Results demonstrated rRNA degradation by the carvacrol/cinnamaldehyde mixture, and this effect was due to carvacrol. Degradation was conserved after encapsulation of the mixture in lipid nanocapsules. Results showed an upregulation of the genes coding for heat shock proteins, such as groES, groEL, dnaK, clpB, and the catalase katE, after exposure to carvacrol/cinnamaldehyde mixture. The catalase was upregulated after carvacrol exposure wich is related to an oxidative stress. The combination of thiourea (hydroxyl radical scavenger) and carvacrol demonstrated a potent bactericidal effect. These results underline the development of defense strategies of the bacteria by synthesis of reactive oxygen species in response to environmental stress conditions, such as carvacrol
Recommendations for embedding simulation in health services
Published online: 06 October 2023Aspirations to achieve quality and safety goals in health services through simulation have led to significant investments in simulation equipment, space and faculty. However, the optimal governance and operational models through which these resources are expertly applied in health services are not known. There is growing evidence supporting âserviceâ models for simulation. In these models, simulation activities are co-designed and delivered by a team of simulation experts in partnership with health service units, specifically targeting quality and safety goals. Embedded simulation specialist teams working within these programs offer benefits not fully captured by traditional models of health education or by traditional systems for quality and safety. In this article, we explore broad and specific recommendations for establishing a simulation consultancy service within an Australian metropolitan health service. We base these recommendations on a review of current Australian practice and healthcare simulation literature, and on a specific example within a large outer metropolitan health service. The broad domains discussed include (1) governance and leadership; (2) human resources; (3) principles and planning; (4) operationalise and evaluate and (5) look to the future. The recommendations recognise that healthcare simulation is moving beyond solely addressing individual learning outcomes. The value of simulation addressing organisation and system objectives through various simulation modalities is increasingly being explored and demonstrating value. There is a growing demand for translational simulation in these contexts, and a consequent requirement for organisations to consider how simulation services can be successfully operationalised. Recommendations included in this paper are discussed and described with the intent of facilitating a deeper appreciation of the complexities associated with, and opportunities afforded by, a well-integrated simulation service.Ellen Davies, Adam Montagu and Victoria Brazi
Synergistic interactions between doxycycline and terpenic components of essential oils encapsulated within lipid nanocapsules against gram negative bacteria
The combination of essential oils (EOs) with antibiotics provides a promising strategy towards combating resistant bacteria. We have selected a mixture of 3 major components extracted from EOs: carvacrol (oregano oil), eugenol (clove oil) and cinnamaldehyde (cinnamon oil). These compounds were successfully encapsulated within lipid nanocapsules (LNCs). The EOs-loaded LNCs were characterised by a noticeably high drug loading of 20% and a very small particle diameter of 114nm. The in vitro interactions between EOs-loaded LNCs and doxycycline were examined via checkerboard titration and time-kill assay against 5 Gram-negative strains: Acinetobacter baumannii SAN, A. baumannii RCH, Klebsiella pneumoniae, Escherichia coli and Pseudomonas aeruginosa. No growth inhibition interactions were found between EOs-loaded LNCs and doxycycline (FIC index between 0.7 and 1.30). However, when bactericidal effects were considered, a synergistic interaction was observed (FBC index equal to 0.5) against all tested strains. A synergistic effect was also observed in time-kill assay (a difference of at least 3 log between the combination and the most active agent alone). Scanning electron microscopy (SEM) was used to visualise the changes in the bacterial membrane. The holes in bacterial envelope and leakage of cellular contents were observed in SE micrographs after exposure to the EOs-LNCs and the doxycycline combination
- âŠ