5,991 research outputs found

    Dominant gain-of-function mutations in Hsp104p reveal crucial roles for the middle region

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    Heat-shock protein 104 (Hsp104p) is a protein-remodeling factor that promotes survival after extreme stress by disassembling aggregated proteins and can either promote or prevent the propagation of prions (protein-based genetic elements). Hsp104p can be greatly overexpressed without slowing growth, suggesting tight control of its powerful protein-remodeling activities. We isolated point mutations in Hsp104p that interfere with this control and block cell growth. Each mutant contained alterations in the middle region (MR). Each of the three MR point mutations analyzed in detail had distinct phenotypes. In combination with nucleotide binding site mutations, Hsp104p(T499I) altered bud morphology and caused septin mislocalization, colocalizing with the misplaced septins. Point mutations in the septin Cdc12p suppressed this phenotype, suggesting that it is due to direct Hsp104p–septin interactions. Hsp104p(A503V) did not perturb morphology but stopped cell growth. Remarkably, when expressed transiently, the mutant protein promoted survival after extreme stress as effectively as did wild-type Hsp104p. Hsp104p(A509D) had no deleterious effects on growth or morphology but had a greatly reduced ability to promote thermotolerance. That mutations in an 11-amino acid stretch of the MR have such profound and diverse effects suggests the MR plays a central role in regulating Hsp104p function

    Ambiguous Criteria

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    Ambiguous Criteria consists of paintings, digital prints, and works on paper including abstract compositions and saturated photographs with swaths of colors and text. The content originates in personal memories: childhood recollections, humorous anecdotes, and images of intimately known places. Alongside this is topical subject matter derived from popular culture, scientific information, and conspiracy theories that have been researched and dismantled by myself. This combination results in a tension that corresponds with the making of the work. Rather than following a linear method when creating I improvise and disrupt the composition through the addition and redaction of material gestures. The resulting works obscure content and remove context. Ambiguous Criteria is an opportunity for these disparate elements to coexist untethered from the restricted plane of reality. Through these abstractions, abstract and tangible concepts can be addressed and dismantled while accepting and embracing a refusal to explicitly define a precise meaning or position

    Measurement of temperature profiles in hot gases and flames

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    Computer program was written for calculation of molecular radiative transfer from hot gases. Shape of temperature profile was approximated in terms of simple geometric forms so profile could be characterized in terms of few parameters. Parameters were adjusted in calculations using appropriate radiative-transfer expression until best fit was obtained with observed spectra

    Periodic Modulation of Extraordinary Optical Transmission through Subwavelength Hole Arrays using Surrounding Bragg Mirrors

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    The enhanced light transmission through an array of subwavelength holes surrounded by Bragg mirrors is studied, showing that the mirrors act to confine the surface plasmons associated with the Extraordinary Optical Transmission effect, forming a surface resonant cavity. The overall effect is increased light transmission intensity by more than a factor of three beyond the already enhanced transmission, independent of whether the Bragg mirrors are on the input or the output side of the incident light. The geometry of the Bragg mirror structures controls the enhancement, and can even reduce the transmission in half. By varying these geometric parameters, we were able to periodically modulate the transmission of light for specific wavelengths, consistent with the propagation and interference of surface plasmon waves in a resonant cavity. FDTD simulations and a wave propagation model verify this effect.Comment: 9 pages, 5 figure

    Super insulation systems for cryogenic test tank Final report

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    Laminate superinsulation system for cryogenic test tank for long term space storage of fluid

    Rigid open-cell polyurethane foam for cryogenic insulation

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    Lightweight polyurethane foam assembled in panels is effective spacer material for construction of self-evacuating multilayer insulation panels for cryogenic liquid tanks. Spacer material separates radiation shields with barrier that minimizes conductive and convective heat transfer between shields
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