1,981 research outputs found

    Propellant dynamic problems in space shuttle vehicles, part 2 Final report

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    Liquid propellant dynamic problems in space shuttle vehicle

    Data on Burned District at Salem, Mass.

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    Nature of Buildings Burned - Materials of Original Construction - Assessed Valuation on Land and Buildings - also Insurance on Buildings and Contents, where obtainable. Arranged according to Name of Owners, Street Location and Classes of Buildings. 20 pages.https://digitalcommons.salemstate.edu/fire_documents/1001/thumbnail.jp

    Fluid physics, thermodynamics, and heat transfer experiments in space

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    An overstudy committee was formed to study and recommend fundamental experiments in fluid physics, thermodynamics, and heat transfer for experimentation in orbit, using the space shuttle system and a space laboratory. The space environment, particularly the low-gravity condition, is an indispensable requirement for all the recommended experiments. The experiments fell broadly into five groups: critical-point thermophysical phenomena, fluid surface dynamics and capillarity, convection at reduced gravity, non-heated multiphase mixtures, and multiphase heat transfer. The Committee attempted to assess the effects of g-jitter and other perturbations of the gravitational field on the conduct of the experiments. A series of ground-based experiments are recommended to define some of the phenomena and to develop reliable instrumentation

    Synthetic Analogues of the Snail Toxin 6-Bromo-2-mercaptotryptamine Dimer (BrMT) Reveal That Lipid Bilayer Perturbation Does Not Underlie Its Modulation of Voltage-Gated Potassium Channels

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    Drugs do not act solely by canonical ligand–receptor binding interactions. Amphiphilic drugs partition into membranes, thereby perturbing bulk lipid bilayer properties and possibly altering the function of membrane proteins. Distinguishing membrane perturbation from more direct protein–ligand interactions is an ongoing challenge in chemical biology. Herein, we present one strategy for doing so, using dimeric 6-bromo-2-mercaptotryptamine (BrMT) and synthetic analogues. BrMT is a chemically unstable marine snail toxin that has unique effects on voltage-gated K+ channel proteins, making it an attractive medicinal chemistry lead. BrMT is amphiphilic and perturbs lipid bilayers, raising the question of whether its action against K+ channels is merely a manifestation of membrane perturbation. To determine whether medicinal chemistry approaches to improve BrMT might be viable, we synthesized BrMT and 11 analogues and determined their activities in parallel assays measuring K+ channel activity and lipid bilayer properties. Structure–activity relationships were determined for modulation of the Kv1.4 channel, bilayer partitioning, and bilayer perturbation. Neither membrane partitioning nor bilayer perturbation correlates with K+ channel modulation. We conclude that BrMT’s membrane interactions are not critical for its inhibition of Kv1.4 activation. Further, we found that alkyl or ether linkages can replace the chemically labile disulfide bond in the BrMT pharmacophore, and we identified additional regions of the scaffold that are amenable to chemical modification. Our work demonstrates a strategy for determining if drugs act by specific interactions or bilayer-dependent mechanisms, and chemically stable modulators of Kv1 channels are reported

    Observation of a narrow structure in p(gamma,K_s)X via interference with phi-meson production

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    We report observation of a narrow peak structure at ~1.54 GeV with a Gaussian width sigma=6 MeV in the missing of K_s in the reaction gamma+p = pK_sK_L. The observed structure may be due to the interference between a strange (or anti-strange) baryon resonance in the pK_L system and the phi(K_sK_L) photoproduction leading to the same final state. The statistical significance of the observed excess of events estimated as the log likelihood ratio of the resonant signal+background hypothesis and the phi-production based background only hypothesis corresponds to 5.3 sigma.Comment: Accepted for publication in Physical Review C, 9 pages, 11 figures, 1 table added, revise

    Experimental determination of the evolution of the Bjorken integral at low Q^2

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    We extract the Bjorken integral Gamma^{p-n}_1 in the range 0.17 < Q^2 < 1.10 GeV^2 from inclusive scattering of polarized electrons by polarized protons, deuterons and 3He, for the region in which the integral is dominated by nucleon resonances. These data bridge the domains of the hadronic and partonic descriptions of the nucleon. In combination with earlier measurements at higher Q^2, we extract the non-singlet twist-4 matrix element f_2.Comment: Quoted world data updated. Minor change in some results, Minor rephrasin

    The Iowa Homemaker vol.1, no.5-6

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    Table of Contents Dean MacKay Takes Well Earned Vacaion by F. W. Beckman, page 1 Playing the Game of Health With Yardstick and Scales by Grace McIlrath and Gladys Dodge, page 2 A Parent-Teacher Association in Every School! by Carolyne E. Forgrave, page 3 Artificial Feeding of Infants Up-to-Date by Belle Lowe, page 4 Making the Most of Your Old Reed Furniture by Glenna Hesse, page 5 The “Little House” That You Will Like by Helen Paschal, page 6 “The High School Girls’ Clothes Line” a Playlet, page 7 Practical Phases of the Love Nest by Eda Lord Murphy, page 8 Putting the Jell Into Jellies and Jams by Millie Lerdall, page

    Differential cross sections for pion charge exchange on the proton at 27.5 MeV

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    We have measured pion single charge exchange differential cross sections on the proton at 27.5 MeV incident π−\pi^- kinetic energy in the center of momentum angular range between 0∘0^\circ and 55∘55^\circ. The extracted cross sections are compared with predictions of the standard pion-nucleon partial wave analysis and found to be in excellent agreement.Comment: ReVTeX v3.0 with aps.sty, 23 pages in e-print format, 7 PostScript Figures and 4 Tables, also available via anonymous ftp at ftp://helena.phys.virginia.edu/pub/preprints/scx.p
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