The role of robotics in computer controlled polishing of large and small optics

Following formal acceptance by ESO of three 1.4m hexagonal off-axis prototype mirror segments, one circular segment, and certification of our optical test facility, we turn our attention to the challenge of segment mass-production. In this paper, we focus on the role of industrial robots, highlighting complementarity with Zeeko CNC polishing machines, and presenting results using robots to provide intermediate processing between CNC grinding and polishing. We also describe the marriage of robots and Zeeko machines to automate currently manual operations; steps towards our ultimate vision of fully autonomous manufacturing cells, with impact throughout the optical manufacturing community and beyond

Robotic automation in computer controlled polishing

We first present a Case Study – the manufacture of 1.4 m prototype mirror-segments for the European Extremely Large Telescope, undertaken by the National Facility for Ultra Precision Surfaces, at the OpTIC facility operated by Glyndwr University. Scale-up to serial-manufacture demands delivery of a 1.4 m off-axis aspheric hexagonal segment with surface precision < 10 nm RMS every four days, compared with a typical year or more for an one-off part. This requires a radically-new approach to large optics fabrication, which will inevitably propagate into wider industrial optics. We report on how these ambitious requirements have stimulated an investigation into the synergy between robots and computer numerically controlled (‘CNC’) polishing machines for optical fabrication. The objective was not to assess which is superior. Rather, it was to understand for the first time their complementary properties, leading us to operate them together as a unit, integrated in hardware and software. Three key areas are reported. First is the novel use of robots to automate currently-manual operations on CNC polishing machines, to improve work-throughput, mitigate risk of damage to parts, and reduce dependence on highly-skilled staff. Second is the use of robots to pre-process surfaces prior to CNC polishing, to reduce total process time. The third draws the threads together, describing our vision of the automated manufacturing cell, where the operator interacts at cell rather than machine level. This promises to deliver a step-change in end-to-end manufacturing times and costs, compared with either platform used on its own or, indeed, the state-of-the-art used elsewhere

The Wolf-Rayet population of the nearby barred spiral galaxy NGC 5068 uncovered by the Very Large Telescope and Gemini

We present a narrow-band Very Large Telescope/Focal Reduced Low-dispersion Spectrograph #1 imaging survey of the SAB(rs)cd spiral galaxy NGC 5068, located at a distance of 5.45 Mpc, from which 160 candidate Wolf–Rayet sources have been identified, of which 59 cases possess statistically significant λ4686 excesses. Follow-up Gemini Multi-Object Spectrograph spectroscopy of 64 candidates, representing 40 per cent of the complete photometric catalogue, confirms Wolf–Rayet signatures in 30 instances, corresponding to a 47 per cent success rate. 21 out of 22 statistically significant photometric sources are spectroscopically confirmed. Nebular emission detected in 30 per cent of the Wolf–Rayet candidates spectrally observed, which enable a re-assessment of the metallicity gradient in NGC 5068. A central metallicity of log (O/H) + 12 ∼ 8.74 is obtained, declining to 8.23 at R25. We combine our spectroscopy with archival Hα images of NGC 5068 to estimate a current star formation rate of Graphic, and provide a catalogue of the 28 brightest H ii regions from our own continuum subtracted Hα images, of which ∼17 qualify as giant H ii regions. Spectroscopically, we identify 24 WC- and 18 WN-type Wolf–Rayet stars within 30 sources since emission-line fluxes indicate multiple Wolf–Rayet stars in several cases. We estimate an additional ∼66 Wolf–Rayet stars from the remaining photometric candidates, although sensitivity limits will lead to an incomplete census of visually faint WN stars, from which we estimate a global population of ∼170 Wolf–Rayet stars. Based on the Hα-derived O star population of NGC 5068 and N(WR)/N(O) ∼ 0.03, representative of the Large Magellanic Cloud, we would expect a larger Wolf–Rayet population of 270 stars. Finally, we have compared the spatial distribution of spectroscopically confirmed WN and WC stars with Sloan Digital Sky Survey derived supernovae, and find both WN and WC stars to be most consistent with the parent population of Type Ib supernovae

Biogeography of Cyanobacterial isiA Genes and Their Link to Iron Availability in the Ocean

The cyanobacterial iron-stress-inducible isiA gene encodes a chlorophyll-binding protein that provides flexibility in photosynthetic strategy enabling cells to acclimate to low iron availability. Here, we report on the diversity and abundance of isiA genes from 14 oceanic stations encompassing large natural gradients in iron availability. Synechococcus CRD1 and CRD2-like isiA genes were ubiquitously identified from tropical and subtropical waters of the Pacific, Atlantic, and Indian Oceans. The relative abundance of isiA-containing Synechococcus cells ranged from less than 10% of the total Synechococcus population in regions where iron is replete such as the North Atlantic subtropical gyre, to over 80% in low-iron but high-nitrate regions of the eastern equatorial Pacific. Interestingly, Synechococcus populations in regions with both low iron and low nitrate concentrations such as the subtropical gyres in the North Pacific and South Atlantic had a low relative abundance of the isiA gene. Indeed, fitting our data into a multiple regression model showed that ∼80% of the variation in isiA relative abundances can be explained by nitrate and iron concentrations, whereas no other environmental variables (temperature, salinity, Chl a) had a significant effect. Hence, isiA has a predictable biogeographical distribution, consistent with the perceived biological role of IsiA as an adaptation to low-iron conditions. Understanding such photosynthetic strategies is critical to our ability to accurately estimate primary production and map nutrient limitation on global scales

Expansion of the ADOR strategy for the synthesis of new zeolites : the synthesis of IPC-12 from zeolite UOV

R.E.M. thanks the Royal Society and the Engineering and Physical Sciences Research Council (Grants EP/K025112/1, EP/K005499/1, EP/L016419/1) for funding work in this area and for providing a Ph.D. studentship to S.E.R. through the Criticat Centre for Doctoral training. R.E.M. and M. O. acknowledge the OP VVV "Excellent Research Teams", project No. CZ.02.1.01/0.0/0.0/15_003/0000417 - CUCAM. J.Č., V.K., and M.T. acknowledge the Czech Science Foundation for the project of the Centre of Excellence (P106/12/G015) and J.Č has received funding from the European Union's Horizon2020 research and innovation programme under grant agreement No 640979. The research leading to these results has received funding from the European Union Seventh Framework Programme under Grant Agreement No. 312483—ESTEEM2 (Integrated Infrastructure Initiative–I3).The assembly-disassembly-organization-reassembly (ADOR) process has been used to disassemble a parent zeolite with the UOV structure type and then reassemble the resulting layers into a novel structure, IPC-12. The structure of the material has previously been predicted computationally and confirmed in our experiments using X-ray diffraction and atomic resolution STEM-HAADF electron microscopy. This is the first successful application of the ADOR process to a material with porous layers.Publisher PDFPeer reviewe

Constraints on the Progenitor System of the Type Ia Supernova SN 2011fe/PTF11kly

Type Ia supernovae (SNe) serve as a fundamental pillar of modern cosmology, owing to their large luminosity and a well-defined relationship between light-curve shape and peak brightness. The precision distance measurements enabled by SNe Ia first revealed the accelerating expansion of the universe, now widely believed (though hardly understood) to require the presence of a mysterious "dark" energy. General consensus holds that Type Ia SNe result from thermonuclear explosions of a white dwarf (WD) in a binary system; however, little is known of the precise nature of the companion star and the physical properties of the progenitor system. Here we make use of extensive historical imaging obtained at the location of SN 2011fe/PTF11kly, the closest SN Ia discovered in the digital imaging era, to constrain the visible-light luminosity of the progenitor to be 10-100 times fainter than previous limits on other SN Ia progenitors. This directly rules out luminous red giants and the vast majority of helium stars as the mass-donating companion to the exploding white dwarf. Any evolved red companion must have been born with mass less than 3.5 times the mass of the Sun. These observations favour a scenario where the exploding WD of SN 2011fe/PTF11kly, accreted matter either from another WD, or by Roche-lobe overflow from a subgiant or main-sequence companion star.Comment: 22 pages, 6 figures, submitte

A new precise mass for the progenitor of the Type IIP SN 2008bk

The progenitor of the Type IIP SN 2008bk was discovered in pre-explosion g'r'i'IYJHKs images, acquired with European Southern Observatory Very Large Telescope FORS, HAWK-I and ISAAC instruments and the Gemini GMOS-S instrument. The wealth of pre-explosion observations makes the progenitor of this SN one of the best studied, since the detection of the progenitor of SN1987A. Previous analyses of the properties of the progenitor were hampered by the limited quality of the photometric calibration of the pre-explosion images and the crowded nature of the field containing the SN. We present new late-time observations of the site of SN2008bk acquired with identical instrument and filter configurations as the pre-explosion observations, and confirm that the previously identified red supergiant star was the progenitor of this SN and has now disappeared. Image subtraction techniques were used to conduct precise photometry of the now missing progenitor, independently of blending from any nearby stars. The nature of the surrounding stellar population and their contribution to the flux attributed to the progenitor in the pre-explosion images are probed using HST WFC3 UVIS/IR observations. In comparison with MARCS synthetic spectra, we find the progenitor was a highly reddened RSG with luminosity log (L/Lsun)=4.84+/-0.11, corresponding to an initial mass of Minit=12.9+/-1.7Msun. The temperature of the progenitor was hotter than previously expected for RSGs (T ~ 4330K), but consistent with new temperatures derived for RSGs using SED fitting techniques. We show that there is evidence for significant extinction of the progenitor, possibly arising in the CSM; but that this dust yields a similar reddening law to dust found in the ISM (E(B-V)=0.77 with Rv=3.1). [Abridged]Comment: 16 pages, 7 figures - submitted to MNRAS (21 July

The role of zinc in the anti-tumour and anti-cachectic activity of D-myo-inositol 1,2,6-triphosphate

Background: D-myo-inositol-1,2,6-triphosphate (a-trinositol, AT) is a polyanionic molecule capable of chelating divalent metal ions with anti-tumour and anti-cachectic activity in a murine model. Methods: To investigate the role of zinc in this process, mice bearing cachexia-inducing MAC16 tumour were treated with AT, with or without concomitant administration of ZnSO4. Results: At a dose of 40mgkg-1, AT effectively attenuated both weight loss and growth of the MAC16 tumour, and both effects were attenuated by co-administration of Zn2+. The concentration of zinc in gastrocnemius muscle increased with increasing weight loss, whereas administration of AT decreased the levels of zinc in plasma, skeletal muscle and tumour, which were restored back to control values after administration of ZnSO4. Conclusion: These results suggest that zinc is important in both tumour growth and cachexia in this animal model

Cotton-hydrogel composite for improved wound healing: antimicrobial activity and anti-inflammatory evaluation - part 2

Infection is one of the major risk factors for the development of chronic wounds.Antimicrobial wound dressing has been pointed out as a viable option for the preven-tion and treatment of wound infections. Thus, we developed a composite materialbased on cotton textile substrates functionalized with cyclodextrin‐hydroxypropylmethyl cellulose‐based hydrogel. The composites' ability to encapsulate and releasegallic acid (antimicrobial phenolic acid) was evaluated, as well as their mechanicalproperties and antimicrobial and anti‐inflammatory capacity. All composites were ableto retain gallic acid in their structure, with similar loading profile. The presence of gal-lic acid on composites was confirmed by FTIR and TGA. Composites storage moduliwas reduced by the presence of gallic acid. The results suggest a straight relationbetween the swelling ability and gallic acid drug delivery profile. The drug deliverymechanism, of the developed composites, was mainly controlled by Fickian diffusion,based on the experimental data fitting to the Peppas‐Sahlin model. Gallic acid antimi-crobial and anti‐inflammatory properties were transferred to the composite materials.According to the results, the developed composites can be applied on the preventionor treatment of chronic woundsThis article is a result of the project TSSiPRO—NORTE‐01‐0145‐ FEDER‐000015—supported by the regional operational program NORTE 2020, under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund. The authors, also, acknowledge the Portuguese Foundation for Science and Technology (FCT) funding from the project UID/CTM/00264/2013 and UID/AGR/00690/2013 and FEDER funds through the COMPETE 2020–Programa Operacional Competitividade e Internacionalização (POCI) with the reference project POCI‐01‐0145‐FEDER‐007136.info:eu-repo/semantics/publishedVersio

Increased expression of the ubiquitin – proteasome pathway in murine myotubes by proteolysis-inducing factor (PIF) is associated with activation of the transcription factor NF-κB

Proteolysis-inducing factor (PIF), isolated from a cachexia-inducing murine tumour, has been shown to stimulate protein breakdown in C 2C12 myotubes. The effect was attenuated by the specific proteasome inhibitor lactacystin and there was an elevation of proteasome 'chymotrypsin-like' enzyme activity and expression of 205 proteasome α-subunits at concentrations of PIF between 2 and 16 nM. Higher concentrations of PIF had no effect. The action of PIF was attenuated by eicosapentaenoic acid (EPA) (50 μM). At a concentration of 4 nM, PIF induced a transient decrease in IκBα levels after 30 min incubation, while no effect was seen at 20 nM PIF. The level of IκBα, an NF-κB inhibitory protein, returned to normal after 60 min. Depletion of IκBα from the cytosol was not seen in myotubes pretreated with EPA, suggesting that the NF-κB/IκB complex was stabilised. At concentrations between 2 and 8 nM, PIF stimulated an increased nuclear migration of NF-κB, which was not seen in myotubes pretreated with EPA. The PIF-induced increase in chymotrypsin-like enzyme activity was also attenuated by the NF-κB inhibitor peptide SN50, suggesting that NF-κB may be involved in the PIF-induced increase in proteasome expression. The results further suggest that EPA may attenuate protein degradation induced by PIF, at least partly, by preventing NF-κB accumulation in the nucleus. © 2003 Cancer Research UK