3,096 research outputs found
Profiling Phospholipids within Atlantic Salmon Salmo salar with Regards to a Novel Terrestrial Omega-3 Oil Source
The development and inclusion of novel oils derived from genetically modified (GM) oilseeds into aquafeeds, to supplement and supplant current terrestrial oilseeds, as well as fish oils, warrants a more thorough investigation into lipid biochemical alterations within finfish species, such as Atlantic salmon. Five tissues were examined across two harvesting timepoints to establish whether lipid isomeric alterations could be detected between a standard commercial diet versus a diet that incorporated the long-chain polyunsaturated fatty acids (LC-PUFA), EPA (eicosapentaenoic acid), and DHA (docosahexaenoic acid), derived from the GM oilseed Camelina sativa. Tissue-dependent trends were detected, indicating that certain organs, such as the brain, have a basal limit to LC-PUFA incorporation, though enrichment of these fatty acids is possible. Lipid acyl alterations, as well as putative stereospecific numbering (sn) isomer alterations, were also detected, providing evidence that GM oils may modify lipid structure, with lipids of interest providing a set of targeted markers by which lipid alterations can be monitored across various novel diets
An Empirical Charge Transfer Potential with Correct Dissociation Limits
The empirical valence bond (EVB) method [J. Chem. Phys. 52, 1262 (1970)] has
always embodied charge transfer processes. The mechanism of that behavior is
examined here and recast for use as a new empirical potential energy surface
for large-scale simulations. A two-state model is explored. The main features
of the model are: (1) Explicit decomposition of the total system electron
density is invoked; (2) The charge is defined through the density decomposition
into constituent contributions; (3) The charge transfer behavior is controlled
through the resonance energy matrix elements which cannot be ignored; and (4) A
reference-state approach, similar in spirit to the EVB method, is used to
define the resonance state energy contributions in terms of "knowable"
quantities. With equal validity, the new potential energy can be expressed as a
nonthermal ensemble average with a nonlinear but analytical charge dependence
in the occupation number. Dissociation to neutral species for a gas-phase
process is preserved. A variant of constrained search density functional theory
is advocated as the preferred way to define an energy for a given charge.Comment: Submitted to J. Chem. Phys. 11/12/03. 14 pages, 8 figure
Tame Functions with strongly isolated singularities at infinity: a tame version of a Parusinski's Theorem
Let f be a definable function, enough differentiable. Under the condition of
having strongly isolated singularities at infinity at a regular value c we give
a sufficient condition expressed in terms of the total absolute curvature
function to ensure the local triviality of the function f over a neighbourhood
of c and doing so providing the tame version of Parusinski's Theorem on complex
polynomials with isolated singularities at infinity.Comment: 20 page
Structure and dynamics of the interface between a binary hard-sphere crystal of NaCl type and its coexisting binary fluid
Molecular dynamics simulations are performed to study the [100] and [111]
orientations of the crystal-melt interface between an ordered two-component
hard sphere with a NaCl structure and its coexisting binary hard-sphere fluid.
The diameter ratio of the two types of hard spheres making up the mixture is
taken to be 0.414. This work complements our earlier interface simulations [J.
Chem. Phys.116, 3410] for the same diameter ratio at lower pressures where the
smaller component is immiscible in the solid and the fluid mixture coexists
with a pure FCC crystal of large particles. Density profiles and diffusion
coefficient profiles are presented for the AB interfacial system. We find that
for this system, the transition from crystal-like to fluid-like behavior of
both the density and diffusion constant profiles occurs over a narrower region
than that seen in our previous studies [J. Chem. Phys. 116, 3410] of the
FCC/binary fluid system. But similar to what was found in the FCC/binary fluid
interface the transition region for the large particle diffusion constant is
shifted about the size of the large particles toward the fluid phase relative
to that for the small particles.Comment: 8 page
Implementation and Validation of 3-D Ice Accretion Measurement Methodology
A research program has been implemented to develop and validate the use of a commercial 3-D laser scanning system to record ice accretion geometry in the NASA Icing Research Tunnel. A main component of the program was the geometric assessment of the 3- D laser scanning system on a 2-D (straight wing) and a 3-D (swept wing) airfoil geometries. This exercise consisted of comparison of scanned ice accretion to castings of the same ice accretion. The scan data were also used to create rapid prototype artificial ice shapes that were scanned and compared to the original ice accretion. The results from geometric comparisons on the straight wing showed that the ice shape models generated through the scan/rapid prototype process compared reasonably well with the cast shapes. Similar results were obtained with the geometric comparisons on the swept wing. It was difficult to precisely compare the scans of the cast shapes to the original ice accretion scans because the cast shapes appear to have shrunk during the mold/casting process by as much as 0.10-inch. However the comparison of the local ice-shape features were possible and produced better results. The rapid prototype manufacturing process was shown to reproduce the original ice accretion scan normally within 0.01-inch
Application of robotics In the clinical laboratory
The basic types of robot are explained, and the performances and
costs of some commercial examples are given. The potential
advantages and problems of introducing robots into clinical
laboratories are identified and the specifcation of a suitable robot
is developed. None of the commercially available robots meets all
aspects of the specificalion, and currently the purchase of a robot is
considered premature for most clinical laboratories
Million-atom molecular dynamics simulation by order-N electronic structure theory and parallel computation
Parallelism of tight-binding molecular dynamics simulations is presented by
means of the order-N electronic structure theory with the Wannier states,
recently developed (J. Phys. Soc. Jpn. 69,3773 (2000)). An application is
tested for silicon nanocrystals of more than millions atoms with the
transferable tight-binding Hamiltonian. The efficiency of parallelism is
perfect, 98.8 %, and the method is the most suitable to parallel computation.
The elapse time for a system of atoms is 3.0 minutes by a
computer system of 64 processors of SGI Origin 3800. The calculated results are
in good agreement with the results of the exact diagonalization, with an error
of 2 % for the lattice constant and errors less than 10 % for elastic
constants.Comment: 5 pages, 3 figure
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