1,338 research outputs found

    The structure of the hard sphere solid

    Full text link
    We show that near densest-packing the perturbations of the HCP structure yield higher entropy than perturbations of any other densest packing. The difference between the various structures shows up in the correlations between motions of nearest neighbors. In the HCP structure random motion of each sphere impinges slightly less on the motion of its nearest neighbors than in the other structures.Comment: For related papers see: http://www.ma.utexas.edu/users/radin/papers.htm

    Stimulation in vitro of galactocerebroside galactosidase by N‐decanoyl 2‐amino‐2‐methylpropanol

    Full text link
    Amides resembling ceramide (fatty acyl sphingosine) were synthesized and tested in vitro for their effects on the rat brain β‐galactosidase which hydrolyzes galactosyl ceramide. The N‐decanoyl derivative of 2‐amino‐2‐methyl‐1‐propanol was most effective, giving a 34% stimulation at 0.15 mM concentration and a 60% stimulation at maximal levels. Addition of a hydroxyl group in the 3 position reduced the degree of stimulation, as did increasing or decreasing the length of the fatty acid portion. Omission of the branched methyl group resulted in inhibition instead of stimulation. Kinetic analysis indicates that the stimulator does not affect the binding of substrate to enzyme, but does speed the rate of hydrolytic action. Stimulation was also observed with the cerebrosidase in spleen and kidney. It is suggested that the stimulators act on an enzyme site other than the substrate‐active site.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141447/1/lipd0056.pd

    Two-point correlation properties of stochastic "cloud processes''

    Full text link
    We study how the two-point density correlation properties of a point particle distribution are modified when each particle is divided, by a stochastic process, into an equal number of identical "daughter" particles. We consider generically that there may be non-trivial correlations in the displacement fields describing the positions of the different daughters of the same "mother" particle, and then treat separately the cases in which there are, or are not, correlations also between the displacements of daughters belonging to different mothers. For both cases exact formulae are derived relating the structure factor (power spectrum) of the daughter distribution to that of the mother. These results can be considered as a generalization of the analogous equations obtained in ref. [1] (cond-mat/0409594) for the case of stochastic displacement fields applied to particle distributions. An application of the present results is that they give explicit algorithms for generating, starting from regular lattice arrays, stochastic particle distributions with an arbitrarily high degree of large-scale uniformity.Comment: 14 pages, 3 figure

    Tiling Spaces are Inverse Limits

    Full text link
    Let M be an arbitrary Riemannian homogeneous space, and let Omega be a space of tilings of M, with finite local complexity (relative to some symmetry group Gamma) and closed in the natural topology. Then Omega is the inverse limit of a sequence of compact finite-dimensional branched manifolds. The branched manifolds are (finite) unions of cells, constructed from the tiles themselves and the group Gamma. This result extends previous results of Anderson and Putnam, of Ormes, Radin and Sadun, of Bellissard, Benedetti and Gambaudo, and of G\"ahler. In particular, the construction in this paper is a natural generalization of G\"ahler's.Comment: Latex, 6 pages, including one embedded figur

    Stability and post critical behavior of supported panel in supersonic gas jet

    Get PDF
    Flat panel stability, partially supported on the elastic base and located in a supersonic gas flow is considered on the basis of the dynamic method. We study an influence of base’s stiffness on the position of the stability region’s boundaries in the plane of loading parameters. For the case of displaceable supports a study of supercritical behavior of the panel is conducted taking into account the additional longitudinal force. Different cases of stability loss of the panel and its behavior in the near and distant supercritical regions are considered

    A New Class of Monoamine Oxidase Inhibitors

    Full text link
    Newly synthesized compounds have been found to inhibit mitochondrial monoamine oxidase (MAO) in mouse brain and rat liver. A series of 2-acylamino-3- tert -aminopropiophenones acted preferentially against MAO type B (2-phenylethylamine as substrate), apparently irreversibly. 2-Decanoylamino-3-morpholinopropiophenone acted similarly in vivo toward the cerebral MAO, producing a dose-related inhibition. At high dose levels, MAO type A was also severely inhibited. The effects were produced rapidly and restoration of enzyme activity also appeared rapidly. The half-life for MAO type A could be estimated from the rate of enzyme reappearance to be 13 h. It is suggested that the amino ketones undergo a Β-elimination reaction at the enzyme's active site, forming a reactive species (an Α,Β-unsaturated ketone), which reacts covalently with a nucleophilic group of the enzyme by a Michael addition. Some other related compounds, derivatives of phenylpropane, also showed inhibitory activity against MAO, particularly against type A (serotonin as substrate). The morpholino compound might have promise as a quickly effective, short-acting inhibitor of MAO type B.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66333/1/j.1471-4159.1980.tb06611.x.pd

    Nutrients elimination from meat processing wastewater using Scenedesmus sp.; optimizations; artificial neural network and kinetics models

    Get PDF
    The potential of an algae-based system as an environmentally friendly and low-cost wa�ter treatment method to eliminate contaminants from water bodies has been considered. The purpose of this research was to see how effective Scenedesmus sp is in eliminating nutrients from meat processing wastewater (MPWW) throughout the phycoremediation process. Response surface methodology (RSM) and an artificial neural network (ANN) model were applied to improve the inactivation process as a function of cell concentra�tions (3–7 log10 CFU/mL) and time (1–13 days). At 103 to 107 cell/mL of Scenedesmus sp., phycoremediation was carried out at atmospheric temperature (28 ± 2 ◦C, ±2500lux for 12:12 h of light/dark and pH 8). The findings documented 73.76% as the highest removal efficacy of total nitrogen (TN) and 77.85% of total phosphorus (TP), 75.40% of ammonia nitrogen (NH4-H), 77.88% of orthophosphate (PO3− 4 ), and 64.97% of chemical oxygen demand (COD). The ANN revealed that both factors contribute significantly to the nutrient removal process. The batch kinetic coefficients of NH4-H removal were Km = 40.10 mg/L and k = 1.43 mg mg −1Chl a d −1 . Meanwhile, for PO3− 4 , 1.07 mg mg −1Chl a d−1 , as well as 42.80 mg/L, were obtained. The NH4-N yield coefficient of NH4-N was Yn = 0.0192 mg Chl a mg −1 while PO3− 4 was equal to Yp = 0.0409 mg Chl a mg −1 . These findings indicated successful use of Scenedesmus sp. for efficient pollutant removal from meat processing wastewater plants

    The effects of using P and G purifier of water during the treatment of severe acute malnutrition

    Get PDF
    Facilitated in Bandundu, D.R.C over a span of 4 months, this study evaluated the efficacy of P&G Purifier of Water, a point-of-use water treatment product produced and provided by Procter & Gamble. The evaluation was conducted by comparing the efficiency of using Ready-to-use-Food (RUTF) and treating domestic water with P&G Purifier of Water versus RUTF alone in the nutrition treatment of severe acute malnutrition (SAM) children under the age of 5 years without medical complications. Two hypotheses were tested: 1.) SAM cases without medical complication benefiting from RUTF + P&G Purifier of Water have a lower prevalence of waterborne diseases during the course of their treatment 2.) SAM children benefiting from RUTF + P&G Purifier of Water have better outcomes in terms of treatment time (shorter) and weight gain (higher). Ultimately, the study determined the importance of promoting P&G Purifier of Water as part of the standard nutrition treatment of SAM children without medical complications, in areas with difficult or no access to clean drinking water
    corecore