279 research outputs found
An optimized algebraic basis for molecular potentials
The computation of vibrational spectra of diatomic molecules through the
exact diagonalization of algebraically determined matrixes based on powers of
Morse coordinates is made substantially more efficient by choosing a properly
adapted quantum-mechanical basis, specifically tuned to the molecular
potential. A substantial improvement is achieved while still retaining the full
advantage of the simplicity and numerical light-weightedness of an algebraic
approach. In the scheme we propose, the basis is parameterized by two
quantities which can be adjusted to best suit the molecular potential through a
simple minimization procedure.Comment: 29 pages, 4 tables and 4 figures, latex. Sumbitted to J. Phys. Chem
Shift of Volatile Organic Compounds (VOCs) in Gluten-Free Hemp-Enriched Sourdough Bread: A Metabolomic Approach
Hemp seed flour represents a potential ingredient for protein enrichment of gluten-free bakery products, the nutritional value of which could be further increased by fermentation with sourdough or with beneficial lactic acid bacteria strains. In this study, a metabolomic approach was used to evaluate the effect of hemp seed flour addition and sourdough fermentation on the production of flavoring and health-related volatile organic compounds (VOCs) in a gluten-free bread. Multivariate analysis of VOCs provided an in-depth description of the effects of hemp seed flour addition and sourdough fermentation on flavoring and bioactive compounds. In particular, an increased concentration of antimicrobial compounds, a larger spectrum of bioactive VOCs and a typical flavoring profile was evidenced in comparison to standard products. Furthermore, an increase of fermentation metabolites was observed in comparison to a standard dough, relating to abundances of 2-butanone-3-hydroxy, acetic acid, ethanol, and 1,4-butanediol. This study provides new insights on the evolution of flavoring and bioactive hemp seed flour constituents during sourdough fermentation, evidencing their retention in baked goods, and describes a new approach that could guide the formulation of innovative, fermented food with enhanced nutritional value
Quantum Diffusion Models
We propose a quantum version of a generative diffusion model. In this
algorithm, artificial neural networks are replaced with parameterized quantum
circuits, in order to directly generate quantum states. We present both a full
quantum and a latent quantum version of the algorithm; we also present a
conditioned version of these models. The models' performances have been
evaluated using quantitative metrics complemented by qualitative assessments.
An implementation of a simplified version of the algorithm has been executed on
real NISQ quantum hardware.Comment: 20 pages, 13 figure
Photoinduced electron-transfer α-deoxygenation of aldonolactones. Efficient synthesis of 2-deoxy-d-arabino-hexono-1,4-lactone
A photoinduced electron-transfer (PET) reaction was used for the deoxygenation at C-2 of aldonolactones derivatized as 2-O-[3-(trifluoromethyl)benzoyl] or benzoyl esters. By irradiation of different D-galactono- and D-glucono-1,4-derivatives, with a 450 W lamp, using 9-methylcarbazole as photosensitizer, the corresponding 2-deoxy-D-lyxo- and 2-deoxy-D-arabino-hexono-1,4-lactones were efficiently obtained.O-[3-(trifluoromethyl)benzoyl] or benzoyl esters. By irradiation of different D-galactono- and D-glucono-1,4-derivatives, with a 450 W lamp, using 9-methylcarbazole as photosensitizer, the corresponding 2-deoxy-D-lyxo- and 2-deoxy-D-arabino-hexono-1,4-lactones were efficiently obtained.D-lyxo- and 2-deoxy-D-arabino-hexono-1,4-lactones were efficiently obtained.Fil: Bordoni, Andrea Veronica. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Muchnik, Rosa. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Marino, MarĂa Carla. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; Argentin
Effects of axial torsion on sp carbon atomic nanowires
Ab-initio calculations within Density Functional Theory combined with
experimental Raman spectra on cluster-beam deposited pure carbon films provide
a consistent picture of sp-carbon chains stabilized by sp^3 or sp^2
terminations, the latter being sensitive to torsional strain. This unexplored
effect promises many exciting applications since it allows one to modify the
conductive states near the Fermi level and to switch on and off the on-chain
pi-electron magnetism.Comment: in print in Phys Rev Let
Systematic HydrogenâBond Manipulations To Establish Polysaccharide StructureâProperty Correlations
A dense hydrogenâbond network is responsible for the mechanical and structural properties of polysaccharides. Random derivatization alters the properties of the bulk material by disrupting the hydrogen bonds, but obstructs detailed structureâfunction correlations. We have prepared wellâdefined unnatural oligosaccharides including methylated, deoxygenated, deoxyfluorinated, as well as carboxymethylated cellulose and chitin analogues with full control over the degree and pattern of substitution. Molecular dynamics simulations and crystallographic analysis show how distinct hydrogenâbond modifications drastically affect the solubility, aggregation behavior, and crystallinity of carbohydrate materials. This systematic approach to establishing detailed structureâproperty correlations will guide the synthesis of novel, tailorâmade carbohydrate materials
Systematic HydrogenâBond Manipulations To Establish Polysaccharide StructureâProperty Correlations
A dense hydrogenâbond network is responsible for the mechanical and structural properties of polysaccharides. Random derivatization alters the properties of the bulk material by disrupting the hydrogen bonds, but obstructs detailed structureâfunction correlations. We have prepared wellâdefined unnatural oligosaccharides including methylated, deoxygenated, deoxyfluorinated, as well as carboxymethylated cellulose and chitin analogues with full control over the degree and pattern of substitution. Molecular dynamics simulations and crystallographic analysis show how distinct hydrogenâbond modifications drastically affect the solubility, aggregation behavior, and crystallinity of carbohydrate materials. This systematic approach to establishing detailed structureâproperty correlations will guide the synthesis of novel, tailorâmade carbohydrate materials
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