Cryogenic Optical Performance of a Lightweighted Mirror Assembly for Future Space Astronomical Telescopes: Correlating Optical Test Results and Thermal Optical Model

A 43cm diameter stacked core mirror demonstrator was interferometrically tested at room temperature down to 250 degrees Kelvin for thermal deformation. The 2.5m radius of curvature spherical mirror assembly was constructed by low temperature fusing three abrasive waterjet core sections between two CNC pocket milled face sheets. The 93% lightweighted Corning ULE mirror assembly represents the current state of the art for future UV, optical, near IR space telescopes. During the multiple thermal test cycles, test results of interferometric test, thermal IR images of the front face were recorded in order to validate thermal optical model

Cryogenic Optical Performance of a Light-weight Mirror Assembly for Future Space Astronomical Telescopes: Optical Test Results and Thermal Optical Model

A 40 cm diameter mirror assembly was interferometrically tested at room temperature down to 250 degrees Kelvin for thermal deformation. The 2.5 m radius of curvature spherical mirror assembly was constructed by low temperature fusing three abrasive waterjet core sections between two face sheets. The 93% lightweighted Corning ULE mirror assembly represents the current state of the art for future UV, optical, near IR space telescopes. During the multiple thermal test cycles, test results of interferometric test, thermal IR images of the front face were recorded in order to validate thermal optical model

Virology under the microscope—a call for rational discourse

Viruses have brought humanity many challenges: respiratory infection, cancer, neurological impairment and immunosuppression to name a few. Virology research over the last 60+ years has responded to reduce this disease burden with vaccines and antivirals. Despite this long history, the COVID-19 pandemic has brought unprecedented attention to the field of virology. Some of this attention is focused on concern about the safe conduct of research with human pathogens. A small but vocal group of individuals has seized upon these concerns – conflating legitimate questions about safely conducting virus-related research with uncertainties over the origins of SARS-CoV-2. The result has fueled public confusion and, in many instances, ill-informed condemnation of virology. With this article, we seek to promote a return to rational discourse. We explain the use of gain-of-function approaches in science, discuss the possible origins of SARS-CoV-2 and outline current regulatory structures that provide oversight for virological research in the United States. By offering our expertise, we – a broad group of working virologists – seek to aid policy makers in navigating these controversial issues. Balanced, evidence-based discourse is essential to addressing public concern while maintaining and expanding much-needed research in virology

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Conformational dynamics of KIR3.1/KIR3.2 channel activation via delta-opioid receptors (DORs)

This study assessed how conformational information encoded by ligand binding to δ-opioid receptors (DORs) is transmitted to Kir3.1/Kir3.2 channels. HEK293 cells were transfected with bioluminescence resonance energy transfer (BRET) donor/acceptor pairs that allowed us to independently evaluate reciprocal interactions among signaling partners. These and co-immunoprecipitation studies indicated that DORs, Gβγ and Kir3 subunits constitutively interacted with one another. GαoA associated with DORs and Gβγ but, despite being part of the complex, no evidence of its direct association with the channel was obtained. DOR activation by different ligands left DOR-Kir3 interactions unmodified, but modulated BRET between DOR-GαoA, DOR-Gβγ, GαoA-Gβγ and Gβγ-Kir3 interfaces. Ligand-induced BRET changes assessing Gβγ-Kir3.1 subunit interaction: i) followed similar kinetics as those monitoring the GαoA-Gβγ interface, ii) displayed same order of efficacy as those observed at the DOR-Gβγ interface, iii) were sensitive to pertussis toxin and iv) were predictive of whether a ligand could evoke channel currents. Conformational changes at the Gβγ/Kir3 interface were lost when Kir3.1 subunits were replaced by a mutant lacking essential sites for Gβγ-mediated activation. Thus, conformational information encoded by agonist binding to the receptor is relayed to the channel via structural rearrangements that involve repositioning of Gαβγ with respect to DORs, GαoA and channel subunits. Further, the fact that BRET changes at the Gβγ-Kir3 interface are predictive of ligand ability to induce channel currents points to these conformational biosensors as screening tools for identifying GPCR ligands that induce Kir3 channel activation