Sub-surface damage issues for effective fabrication of large optics

A new ultra precision large optics grinding machine, BoX®has been developed at Cranfield University. BoX®islocated at the UK's Ultra Precision Surfaces laboratory at the OpTIC Technium. This machine offers a rapidand economic solution for grinding large off-axis aspherical and free-form optical components.This paper presents an analysis of subsurface damage assessments of optical ground materials produced usingdiamond resin bonded grinding wheels. The specific materials used, Zerodur®and ULE®are currently understudy for making extremely large telescope (ELT) segmented mirrors such as in the E-ELT project.The grinding experiments have been conducted on the BoX®grinding machine using wheels with grits sizes of76 μm, 46 μm and 25 μm. Grinding process data was collected using a Kistler dynamometer platform. Thehighest material removal rate (187.5 mm3/s) used ensures that a 1 metre diameter optic can be ground in lessthan 10 hours. The surface roughness and surface profile were measured using a Form Talysurf. The subsurfacedamage was revealed using a sub aperture polishing process in combination with an etching technique.These results are compared with the targeted form accuracy of 1 μm p-v over a 1 metre part, surface roughnessof 50-150 nm RMS and subsurface damage in the range of 2-5 μm. This process stage was validated on a 400mm ULE®blank and a 1 metre hexagonal Z

Physiological evidence for plasticity in glycolate/glycerate transport during photorespiration

© 2016, The Author(s). Photorespiration recycles fixed carbon following the oxygenation reaction of Ribulose, 1–5, carboxylase oxygenase (Rubisco). The recycling of photorespiratory C2 to C3 intermediates is not perfectly efficient and reduces photosynthesis in C3 plants. Recently, a plastidic glycolate/glycerate transporter (PLGG1) in photorespiration was identified in Arabidopsis thaliana, but it is not known how critical this transporter is for maintaining photorespiratory efficiency. We examined a mutant deficient in PLGG1 (plgg1-1) using modeling, gas exchange, and Rubisco biochemistry. Under low light (under 65 μmol m−2 s−1 PAR), there was no difference in the quantum efficiency of CO2 assimilation or in the photorespiratory CO2 compensation point of plgg1-1, indicating that photorespiration proceeded with wild-type efficiency under sub-saturating light irradiances. Under saturating light irradiance (1200 μmol m−2 s−1 PAR), plgg1-1 showed decreased CO2 assimilation that was explained by decreases in the maximum rate of Rubisco carboxylation and photosynthetic linear electron transport. Decreased rates of Rubisco carboxylation resulted from probable decreases in the Rubisco activation state. These results suggest that glycolate/glycerate transport during photorespiration can proceed in moderate rates through an alternative transport process with wild-type efficiencies. These findings also suggest that decreases in net CO2 assimilation that occur due to disruption to photorespiration can occur by decreases in Rubisco activity and not necessarily decreases in the recycling efficiency of photorespiration

Memory TCR repertoires analyzed long-term reflect those selected during the primary response

Normal T cell repertoire selection and evolution in antigen-specific responses is poorly understood. We have recently described an MHC class I-restricted response characterized by an overwhelming expansion of CD8 cells expressing a Vβ10 TCR, thus allowing the identification of antigen-selected cells directly ex vivo. Our present strategy to follow the overall TCR repertoire selection was to monitor the expression of a particular TCR α chain (Vα8) on antigen-selected Vβ10+ cells by four-color flow cytometry. We demonstrate that while there is substantial variation among the responder mice in Vα8 usage, the repertoires of individual animals remain relatively stable over long periods of time (>1 year), with or without repeated antigenic challenge. Thus if any evolution of this response occurs upon re-exposure to antigen, it would appear not to skew the TCR repertoire established during the primary respons

Comparison of dimethyl sulfoxide treated highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) electrodes for use in indium tin oxide-free organic electronic photovoltaic devices

Indium tin oxide (ITO)-free organic photovoltaic (OPV) devices were fabricated using highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the transparent conductive electrode (TCE). The intrinsic conductivity of the PEDOT:PSS films was improved by two different dimethyl sulfoxide (DMSO) treatments – (i) DMSO was added directly to the PEDOT:PSS solution (PEDOT:PSSADD) and (ii) a pre-formed PEDOT:PSS film was immersed in DMSO (PEDOT:PSSIMM). X-ray photoelectron spectroscopy (XPS) and conductive atomic force microscopy (CAFM) studies showed a large amount of PSS was removed from the PEDOT:PSSIMM electrode surface. OPV devices based on a poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) bulk hetrojunction showed that the PEDOT:PSSIMM electrode out-performed the PEDOT:PSSADD electrode, primarily due to an increase in short circuit current density from 6.62 mA cm−2 to 7.15 mA cm−2. The results highlight the importance of optimising the treatment of PEDOT:PSS electrodes and demonstrate their potential as an alternative TCE for rapid processing and low-cost OPV and other organic electronic devices

Freeform Deposition Method for Coolant Channel Closeout

A method is provided for fabricating a coolant channel closeout jacket on a structure having coolant channels formed in an outer surface thereof. A line of tangency relative to the outer surface is defined for each point on the outer surface. Linear rows of a metal feedstock are directed towards and deposited on the outer surface of the structure as a beam of weld energy is directed to the metal feedstock so-deposited. A first angle between the metal feedstock so-directed and the line of tangency is maintained in a range of 20-90.degree.. The beam is directed towards a portion of the linear rows such that less than 30% of the cross-sectional area of the beam impinges on a currently-deposited one of the linear rows. A second angle between the beam and the line of tangency is maintained in a range of 5-65 degrees

Triggered Electrical Stimulation Cueing to Address Hypofunctioning Peroneus Muscle in the Treatment of Chronic Ankle Instability: Two Repeated Single Case Designs

Background: Approximately two million ankle sprains occur in the United States annually. Lateral ankle sprains (LAS) account for 85% of all ankle sprains, 74% of those individuals report continued symptoms following the initial insult. Persistent pain and instability following ankle sprain is indicative of chronic ankle instability (CAI). There are many interventions to address hypofunctioning muscle including electrical stimulation (ES) and it is known that peripheral ES changes muscle behavior. The purpose of this pilot study was to investigate the effect of electrical stimulation of the peroneal muscles combined with 3 exercises for the treatment of CAI.Methods: Two participants with CAI were recruited for this repeated single case design. The Cumberland Ankle Instability Tool (CAIT), the modified Star Excursion Balance Test (mSEBT), and center of pressure (CoP) was measured. A single limb hop to stabilization protocol and single limb stance activities were combined with manual triggered electrical stimulation for six sessions.Results: Improvements in CAIT scores for both patients were observed. There was no statistically significant change in mSEBT scores. Center of Pressure measurement improvements varied between subjects. For subject 1, there was no significant change in CoP in eyes open and eyes closed conditions. For subject 2, there was a significant change in the anterior/posterior CoP data points in both conditions.Discussion: In individuals with CAI, the addition of electrical stimulation to a single limb stance and hop stabilization protocol for hypofunctioning peroneal muscles led to positive CAI outcomes as measured by improved CAIT scores and improved CoP measurement in one subject