Thin KAPTON polyimide films vacuum formed at high temperature retain their shape at temperatures to 450 K

Purpose of investigation was to identify candidate materials for self-evacuating multilayer insulation systems to be used on liquid hydrogen tanks on space shuttle, which would survive re-entry temperatures and mechanical and thermal cycling of one hundred flights

Lightweight modular multilayer insulation Final report

Self evacuating multilayer insulation system of aluminized Mylar and polyurethane foam for liquid hydrogen tank

Lightweight, self-evacuated insulation panels

Multilayer insulation of prefabricated panels is developed for cryogenic storage tanks. System utilizes panels of aluminized Mylar separated by sheets of low conductivity polyurethane foam. Panels are self-evacuated by cryopumping of gaseous carbon dioxide at time of use

Rigid open-cell polyurethane foam for cryogenic insulation

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

Lightweight multilayer insulation system Final report

Self evacuating multilayer insulation panel systems for liquid hydrogen space tankag

On Resource-bounded versions of the van Lambalgen theorem

The van Lambalgen theorem is a surprising result in algorithmic information theory concerning the symmetry of relative randomness. It establishes that for any pair of infinite sequences $A$ and $B$, $B$ is Martin-L\"of random and $A$ is Martin-L\"of random relative to $B$ if and only if the interleaved sequence $A \uplus B$ is Martin-L\"of random. This implies that $A$ is relative random to $B$ if and only if $B$ is random relative to $A$ \cite{vanLambalgen}, \cite{Nies09}, \cite{HirschfeldtBook}. This paper studies the validity of this phenomenon for different notions of time-bounded relative randomness. We prove the classical van Lambalgen theorem using martingales and Kolmogorov compressibility. We establish the failure of relative randomness in these settings, for both time-bounded martingales and time-bounded Kolmogorov complexity. We adapt our classical proofs when applicable to the time-bounded setting, and construct counterexamples when they fail. The mode of failure of the theorem may depend on the notion of time-bounded randomness

Factors influencing staff nurses' decisions for non-documentation of patient response to analgesia administration

• The purpose of this descriptive field study is to determine what factors influence staff nurses' decisions for non-documentation of patients' response to analgesic administration. • The study, based on Herbert Simon's descriptive model of decision making, has two components: (a) to determine staff nurses' perceptions of the factors that influence their documentation as well as how frequently they document analgesic administration and (b) to determine the actual frequency of nurses' documentation. • Data collected from 67 staff nurses using a questionnaire designed for this study and through an audit of 65 patients' charts allowed comparison of nurses' perceptions with their actual practice. • Analysis involved both quantitative and qualitative approaches. • The results of the study have implications for nurse educators and nurse administrators.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73890/1/j.1365-2702.1992.tb00112.x.pd

Energetic particle loss mechanisms in reactor-scale equilibria close to quasisymmetry

Collisionless physics primarily determines the transport of fusion-born alpha particles in 3D equilibria. Several transport mechanisms have been implicated in stellarator configurations, including stochastic diffusion due to class transitions, ripple trapping, and banana drift-convective orbits. Given the guiding center dynamics in a set of six quasihelical and quasiaxisymmetric equilibria, we perform a classification of trapping states and transport mechanisms. In addition to banana drift convection and ripple transport, we observe substantial non-conservation of the parallel adiabatic invariant which can cause losses through diffusive banana tip motion. Furthermore, many lost trajectories undergo transitions between trapping classes on longer time scales, either with periodic or irregular behavior. We discuss possible optimization strategies for each of the relevant transport mechanisms. We perform a comparison between fast ion losses and metrics for the prevalence of mechanisms such as banana-drift convection [1], transitioning orbits, and wide orbit widths. Quasihelical configurations are found to have natural protection against ripple-trapping and diffusive banana tip motion leading to a reduction in prompt losses

Model-guided metabolic engineering of Pseudomonas taiwanensis VLB120 for the production of methyl ketones

Aliphatic methyl ketones are discussed as promising novel diesel blendstocks because of their favorable cetane numbers. To achieve sustainable production of these compounds, bio-based production in engineered microbes is followed and successful synthesis in Escherichia coli1,2,3 and Pseudomonas putida4 has recently been shown. In this presentation, we report on the metabolic engineering of Pseudomonas taiwanensis VLB1205 for the production of saturated and monounsaturated medium chain methyl ketones (C11, C13, C15, C17). Major arguments for the use of this microbe are its metabolic versatility, high tolerance of organic solvents5 and ease of cultivation. P. taiwanensis VLB120 can grow on various carbon sources besides glucose such as glycerol, an important by-product of biodiesel production, as well as on major components of biomass hydrolysate such as xylose, organic acids and aromatic compounds, e.g., 4-hydroxybenzoate4. Further, its superior redox cofactor regeneration capability6 might benefit the synthesis of the reduced, aliphatic target compounds. The transformation of P. taiwanensis VLB120 into a microbial cell factory for methyl ketone production was achieved by: (i) overproduction of the fatty acyl-CoA synthetase FadB to increase acyl-CoA availability, (ii) oxidation of acyl-CoA to a trans-2-enoyl-CoA by a heterologously expressed acyl-CoA oxidase from Micrococcus luteus, (iii) conversion of this intermediate to β-hydroxyacyl-CoA and further oxidation to a β -ketoacyl-CoA by overexpression of the native fadB gene, (iv) increased thioesterase activity by overexpression of fadM to form free β -keto acids, which spontaneously decarboxylate to methyl ketones. The 1st generation production strain yielded 550 mg L-1aq methyl ketones in a batch fermentation with in situ product extraction into a second organic layer of n-decane. Further strain optimization was guided by metabolic modeling, which suggested an additional deletion of the acyl-CoA thioesterase II (tesB). TesB hydrolyzes acyl-CoA to free fatty acids, hence, reverses the desired FadD reaction. In a simple batch fermentation, the proposed gene deletion resulted in a 2.5-fold increased product titer of 1.4 g L-1aq while 9.4 g L-1aq were reached in fed-batch cultivations. Additional, successful strategies tested in parallel were the deletion of the pha operon, responsible for polyhydroxyalkanoate synthesis and deletion of a fadA homologue in the 1st generation production strain, with the later resulting in an even 4-fold improvement of the product titer. While the production of 9.4 g L-1aq is already the highest reported titer of recombinantly produced methyl ketones so far, consolidation of all successfully tested engineering strategies holds great promise to significantly boost methyl ketone production in P. taiwanensis VLB120 to even higher titers. Overall, the results of this study underline the high potential of P. taiwanensis VLB120 for the production of methyl ketones and highlight model-guided metabolic engineering as a means to rationalize and accelerate strain optimization efforts. 1Dong et al. 2018: doi:10.1101/496497 2Goh et al. 2012: doi: 10.1128/AEM.06785-11 3Goh et al. 2014: doi: 10.1016/j.ymben.2014.09.003. 4Goh et al. 2018: doi: 10.1002/bit.26558. 5Rühl et al. 2009: doi: 10.1128/AEM.00225-09 6Blank et al. 2008: doi: 10.1111/j.1742-4658.2008.06648.x

The cellular heat shock response monitored by chemical exchange saturation transfer MRI

CEST-MRI of the rNOE signal has been demonstrated in vitro to be closely linked to the protein conformational state. As the detectability of denaturation and aggregation processes on a physiologically relevant scale in living organisms has yet to be verified, the aim of this study was to perform heat-shock experiments with living cells to monitor the cellular heat-shock response of the rNOE CEST signal. Cancer cells (HepG2) were dynamically investigated after a mild, non-lethal heat-shock of 42 °C for 20 min using an MR-compatible bioreactor system at 9.4 T. Reliable and fast high-resolution CEST imaging was realized by a relaxation-compensated 2-point contrast metric. After the heat-shock, a substantial decrease of the rNOE CEST signal by 8.0 ± 0.4% followed by a steady signal recovery within a time of 99.1 ± 1.3 min was observed in two independent trials. This continuous signal recovery is in coherence with chaperone-induced refolding of heat-shock induced protein aggregates. We demonstrated that protein denaturation processes influence the CEST-MRI signal on a physiologically relevant scale. Thus, the protein folding state is, along with concentration changes, a relevant physiological parameter for the interpretation of CEST signal changes in diseases that are associated with pathological changes in protein expression, like cancer and neurodegenerative diseases