1,315 research outputs found
Optical and mechanical design of the extreme AO coronagraphic instrument MagAO-X
Here we review the current optical mechanical design of MagAO-X. The project
is post-PDR and has finished the design phase. The design presented here is the
baseline to which all the optics and mechanics have been fabricated. The
optical/mechanical performance of this novel extreme AO design will be
presented here for the first time. Some highlights of the design are: 1) a
floating, but height stabilized, optical table; 2) a Woofer tweeter (2040
actuator BMC MEMS DM) design where the Woofer can be the current f/16 MagAO ASM
or, more likely, fed by the facility f/11 static secondary to an ALPAO DM97
woofer; 3) 22 very compact optical mounts that have a novel locking clamp for
additional thermal and vibrational stability; 4) A series of four pairs of
super-polished off-axis parabolic (OAP) mirrors with a relatively wide FOV by
matched OAP clocking; 5) an advanced very broadband (0.5-1.7micron) ADC design;
6) A Pyramid (PWFS), and post-coronagraphic LOWFS NCP wavefront sensor; 7) a
vAPP coronagraph for starlight suppression. Currently all the OAPs have just
been delivered, and all the rest of the optics are in the lab. Most of the
major mechanical parts are in the lab or instrument, and alignment of the
optics has occurred for some of the optics (like the PWFS) and most of the
mounts. First light should be in 2019A.Comment: 10 pages, proc. SPIE 10703, Adaptive Optics IV, Austin TX, June 201
Characterisation and screening of antimicrobial essential oil components against clinically important antibiotic-resistant bacteria using thin layer chromatography-direct bioautography hyphenated with GC-MS, LC-MS and NMR
Introduction
The antimicrobial activity of many essential oils (EOs) is well established, indicating that EOs may be a source of compounds for antimicrobial drug development. Thin layer chromatographyâdirect bioautography (TLCâDB) can quickly identify antimicrobial components in complex mixtures and can be applied to the screening of EOs for lead compounds.
Objectives
This study aimed to identify antimicrobial components of oregano, rosewood and cumin EOs against antibioticâsensitive and âresistant bacteria using TLCâDB and a multiâfaceted approach of GCâMS, LCâMS and NMR techniques to characterise bioactive compounds. The study also aimed to quantify the antimicrobial activity of bioactive compounds in order to evaluate their potential for the development of therapies against antibioticâresistant bacteria.
Materials and Methods
EOs were eluted on TLC plates and sprayed with a suspension of Staphylococcus aureus, Enterococcus faecium, Escherichia coli or Pseudomonas aeruginosa (antibioticâsensitive and âresistant isolates). Zones of inhibition, visualised with iodonitrotetrazolium chloride, were subject to GCâMS, LCâMS and NMR to characterise the bioactive compounds.
Results
Seven compounds were identified from the three EOs using GCâMS, while LCâMS and NMR failed to detect the presence of any further nonâvolatile or heat labile compounds. Carvacrol was most antimicrobial compound identified, with minimum inhibitory concentrations ranging 0.99â31.62 mM.
Conclusion
\ud
The identified antimicrobial compounds present in oregano, rosewood and cumin EOs including carvacrol may be candidates for the development of novel antimicrobial therapies against antibioticâresistant bacteria
Ocular Pathology Relevant to Glaucoma in a Gja1(Jrt) Mouse Model of Human Oculodentodigital Dysplasia
PURPOSE. Oculodentodigital dysplasia (ODDD) is a human disorder caused by mutations in the gap junction alpha 1 (GJA1) gene encoding the connexin43 (Cx43) gap junction protein. Causal links between GJA1 mutations and glaucoma are not understood. The purpose in this study was to examine the ocular phenotype for Gja1(Jrt/+) mice harboring a Cx43 G60S mutation. METHODS. In young Gja1(Jrt/+) mice, Cx43 abundance was assessed with a Western blot, and Cx43 localization was visualized using immunohistochemistry and confocal microscopy. Intraocular pressure (IOP) was measured by rebound tonometry, and eye anatomy was imaged using ocular coherence tomography (OCT). Hematoxylin and eosin (H&E)-stained eye sections were examined for ocular histopathology related to the development of glaucoma. RESULTS. Decreased Cx43 protein levels were evident in whole eyes from Gja1(Jrt/+) mice compared with those of wild-type mice at postnatal day 1 (P = 0.005). Cx43 immunofluorescence in ciliary bodies of Gja1(Jrt/+) mice was diffuse and intracellular, unlike the gap junction plaques prevalent in wildtype mice. IOP in Gja1(Jrt/+) mice changed during postnatal development, with significantly lower IOP at 21 weeks of age in comparison to the IOP of wild-type eyes. Microphthalmia, enophthalmia, anterior angle closure, and reduced pupil diameter were observed in Gja1(Jrt/+) mice at all ages examined. Ocular histology showed prominent separations between the pigmented and nonpigmented ciliary epithelium of Gja1(Jrt/+) mice, split irides, and alterations in the number and distribution of nuclei in the retina. CONCLUSIONS. Detailed phenotyping of Gja1(Jrt/+) eyes offers a framework for elucidating human ODDD ocular disease mechanisms and evaluating new treatments designed to protect ocular synaptic network integrity
Designing for humanâagent collectives: display considerations
The adoption of unmanned systems is growing at a steady rate, with the promise of improved task effectiveness and decreased costs associated with an increasing multitude of operations. The added flexibility that could potentially enable a single operator to control multiple unmanned platforms is thus viewed as a potential game-changer in terms of both cost and effectiveness. The use of advanced technologies that facilitate the control of multiple systems must lie within control frameworks that allow the delegation of authority between the human and the machine(s). Agent-based systems have been used across different domains in order to offer support to human operators, either as a form of decision support offered to the human or to directly carry out behaviours that lead to the achievement of a defined goal. This paper discusses the need for adopting a humanâagent interaction paradigm in order to facilitate an effective humanâagent partnership. An example of this is discussed, in which a single human operator may supervise and control multiple unmanned platforms within an emergency response scenario
Improved Orbital Constraints and H Photometric Monitoring of the Directly Imaged Protoplanet Analog HD 142527 B
Companions embedded in the cavities of transitional circumstellar disks have
been observed to exhibit excess luminosity at H, an indication that
they are actively accreting. We report 5 years (2013-2018) of monitoring of the
position and H excess luminosity of the embedded, accreting low-mass
stellar companion HD 142527 B from the MagAO/VisAO instrument. We use pyklip, a
python implementation of the Karhounen-Loeve Image Processing algorithm, to
detect the companion. Using pyklip forward modeling, we constrain the relative
astrometry to precision and achieve sufficient photometric
precision ( error) to detect changes in the H
contrast of the companion over time. In order to accurately determine the
relative astrometry of the companion, we conduct an astrometric calibration of
the MagAO/VisAO camera against 20 years of Keck/NIRC2 images of the Trapezium
cluster. We demonstrate agreement of our VisAO astrometry with other published
positions for HD 142527 B, and use orbitize! to generate a posterior
distribution of orbits fit to the relative astrometry of HD 142527 B. Our data
suggest that the companion is close to periastron passage, on an orbit
significantly misinclined with respect to both the wide circumbinary disk and
the recently observed inner disk encircling HD 142527 A. We translate observed
H-alpha contrasts for HD 142527 B into mass accretion rate estimates on the
order of . Photometric
variation in the H-alpha excess of the companion suggests that the accretion
rate onto the companion is variable. This work represents a significant step
towards observing accretion-driven variability onto protoplanets, such as PDS
70 b\&c.Comment: Accepted to the Astronomical Journal. 32 pages, 16 figures, 8 tables,
4 appendice
Thermoregulatory ability and mechanism do not differ consistently between neotropical and temperate butterflies
Climate change is a major threat to species worldwide, yet it remains uncertain whether tropical or temperate species are more vulnerable to changing temperatures. To further our understanding of this, we used a standardised field protocol to (1) study the buffering ability (ability to regulate body temperature relative to surrounding air temperature) of neotropical (Panama) and temperate (the United Kingdom, Czech Republic and Austria) butterflies at the assemblage and family level, (2) determine if any differences in buffering ability were driven by morphological characteristics and (3) used ecologically relevant temperature measurements to investigate how butterflies use microclimates and behaviour to thermoregulate. We hypothesised that temperate butterflies would be better at buffering than neotropical butterflies as temperate species naturally experience a wider range of temperatures than their tropical counterparts. Contrary to our hypothesis, at the assemblage level, neotropical species (especially Nymphalidae) were better at buffering than temperate species, driven primarily by neotropical individuals cooling themselves more at higher air temperatures. Morphology was the main driver of differences in buffering ability between neotropical and temperate species as opposed to the thermal environment butterflies experienced. Temperate butterflies used postural thermoregulation to raise their body temperature more than neotropical butterflies, probably as an adaptation to temperate climates, but the selection of microclimates did not differ between regions. Our findings demonstrate that butterfly species have unique thermoregulatory strategies driven by behaviour and morphology, and that neotropical species are not likely to be more inherently vulnerable to warming than temperate species
Real world outcomes of biopsy-proven oncocytic neoplasm of the kidney managed by surveillance.
OBJECTIVES: To evaluate outcomes of patients diagnosed with oncocytic renal neoplasms on routine renal mass biopsy and to describe the natural history of these tumours when managed with surveillance as opposed to immediate intervention. To report disease-specific survival. PATIENTS AND METHODS: Patients were identified from a retrospective review of pathology databases from three tertiary referral centres that utilise renal mass biopsy in routine clinical practice. All patients with biopsy-proven oncocytic tumours were included and a retrospective review of online patient records was undertaken. RESULTS: There were 184 biopsy-proven oncocytic renal neoplasms identified in 172 patients. There were two biopsy complications (both pneumothorax, Clavien-Dindo Grade I). Of these lesions, 135 were reported as oncocytomas or oncocytic renal neoplasms that were not further classified and 37 were reported as chromophobe carcinoma (ChRCC). The median age at diagnosis was 70 (33-88). The average tumour diameter at diagnosis was 33âmm. One hundred seven tumours were initially managed with surveillance (including 13 ChRCC) with a minimum follow-up of 6âmonths and a median of 39âmonths (6-144) whereas 49 patients underwent immediate treatment. The mean growth rate across all oncocytic renal neoplasms managed by surveillance was 3âmm/year. There was no statistically significant difference in growth rates between oncocytic renal neoplasms and ChRCC. Thirteen patients with oncocytic renal neoplasms initially managed by surveillance moved on to an active management strategy during follow-up. The clinical indication given for a change from surveillance was tumour growth in 12 cases and patient choice in 1 case. Where definitive pathology was available, there was 85% concordance with the biopsy. There were no cases of development of metastatic disease or disease-related morbidity or mortality during the study. CONCLUSIONS: This multicentre retrospective cohort study supports the hypothesis that selected biopsy-proven oncocytic renal neoplasms can be safely managed with surveillance in the medium term. Routine renal mass biopsy may reduce surgery for benign or indolent renal tumours and the potential associated morbidity for these patients
- âŠ