49 research outputs found
Scattering states of a particle, with position-dependent mass, in a symmetric heterojunction
The study of a particle with position-dependent effective mass (pdem), within
a double heterojunction is extended into the complex domain --- when the region
within the heterojunctions is described by a non Hermitian
symmetric potential. After obtaining the exact analytical solutions, the
reflection and transmission coefficients are calculated, and plotted as a
function of the energy. It is observed that at least two of the characteristic
features of non Hermitian symmetric systems --- viz., left / right
asymmetry and anomalous behaviour at spectral singularity, are preserved even
in the presence of pdem. The possibility of charge conservation is also
discussed.Comment: 12 pages, including 6 figures; Journal of Physics A : Math. Theor.
(2012
Exact Solutions of the Duffin Kemmer Petiau Equation for the Deformed Hulthen Potential
Using the Nikiforov Uvarov method, an application of the relativistic Duffin
Kemmer Petiau equation in the presence of a deformed Hulthen potential is
presented for spin zero particles. We derived the first order coupled
differential radial equations which enable the energy eigenvalues as well as
the full wavefunctions to be evaluated by using of the Nikiforov Uvarov method
that can be written in terms of the hypergeometric polynomials.Comment: 8 pages. submitted to Physica Script
Physical and oxidative stability of high fat fish oil-in-water emulsions stabilized with sodium caseinate and phosphatidylcholine as emulsifiers
Identification of emulsifier potato peptides by bioinformatics: application to omega-3 delivery emulsions and release from potato industry side streams
We are grateful for the financial support from Innovation Fund Denmark (Grant nr: 7045-00021B, PROVIDE project). We also acknowledge K.M.C. amba (Brande, Denmark) and A.K.V. amba (Langholt, Denmark) for providing the potato samples used in this study.In this work, we developed a novel approach combining bioinformatics, testing of functionality and bottom-up proteomics to obtain peptide emulsifiers from potato side-streams. This is a significant advancement in the process to obtain emulsifier peptides and it is applicable to any type of protein. Our results indicated that structure at the interface is the major determining factor of the emulsifying activity of peptide emulsifiers. Fish oil-in-water emulsions with high physical stability were stabilized with peptides to be predicted to have facial amphiphilicity: (i) peptides with predominantly α-helix conformation at the interface and having 18–29 amino acids, and (ii) peptides with predominantly β-strand conformation at the interface and having 13–15 amino acids. In addition, high physically stable emulsions were obtained with peptides that were predicted to have axial hydrophobic/hydrophilic regions. Peptides containing the sequence FCLKVGV showed high in vitro antioxidant activity and led to emulsions with high oxidative stability. Peptide-level proteomics data and sequence analysis revealed the feasibility to obtain the potent emulsifier peptides found in this study (e.g. γ-1) by trypsin-based hydrolysis of different side streams in the potato industry.Innovation Fund Denmark
7045-00021
Overview of the techniques used for the study of non-terrestrial bodies: Proposition of novel non-destructive methodology
Meteorites and impact glasses have been largely analysed using different techniques, but most studies
have been focused on their geologicalemineralogical characterization and isotopic ratios, mainly of a
destructive nature. However, much more information can be gained by applying novel non-destructive
analytical procedures and techniques that have been scarcely used to analyse these materials. This
overview presents some new methodologies to study these materials and compares these new approaches
with the commonly used ones. Techniques such as X-Ray Fluorescence (XRF) and Laser Induced
Breakdown Spectroscopy (LIBS), for elemental characterization, the hyphenated Raman spectroscopy-
SEM/EDS and the combination of them, allow extracting simultaneous information from elemental,
molecular and structural data of the studied sample; furthermore, the spectroscopic image capabilities of
such techniques allow a better understanding of the mineralogical distribution.
© 2017 Elsevier B.V. All rights reserved.Ministerio de Economía, Industria y Competitividad (project ESP2014-56138-C3-2-R
Interlaboratory study on lipid oxidation during accelerated storage trials with rapeseed and sunflower oil analyzed by conjugated dienes as primary oxidation products
11 Páginas.-- 5 Figuras.-- 2 Tablas.-- Material suplementarioAccelerated storage tests are frequently used to assess the oxidative stability of foods and related systems due to its reproducibility. Various methods and experimental conditions are used to measure lipid oxidation. Differences between laboratories make it necessary to determine the repeatability and reproducibility of oxidation tests performed under the same conditions. The objective of the present interlaboratory study was to evaluate the outcome of a storage test for two different bulk oils, sunflower oil (SFO) and rapeseed oil (RSO), during a period of 9 weeks at 20°C, 30°C, 40°C, and 60°C. Sixteen laboratories were provided with bottled oils and conducted the storage tests according to a detailed protocol. Lipid oxidation was monitored by the formation of conjugated dienes (CD) and the activation energy (Ea) was determined for comparative purposes and statistically evaluated. An increase in CD formation was observed for both oils when the storage temperature was increased in all laboratories. The Ea,1 ranged from 47.9 to 73.3 kJ mol−1 in RSO and from 27.8 to 62.6 kJ mol−1 in SFO, with average values of 58.2 and 46.8 kJ mol−1, respectively. The reproducibility coefficients were 10.9% and 18.2% for RSO and SFO, respectively. Practical applications: In order to compare results on oxidative stability of foods derived from different studies, the reproducibility of storage tests and methods employed to evaluate the oxidation level should be considered. This study provides fundamental data on the reproducibility of lipid oxidation under accelerated storage conditions and defines important parameters to be considered for the conduction of experiments.Open access funding enabled and organized by Projekt DEAL.
We thank Brökelmann + Co – Oelmühle GmbH + Co for the donation of the vegetable oils. The authors gratefully acknowledge Lina Stuthmann from the Food Technology Division, Kiel University and Inge Holmberg from the National Food Institute, Technical University of Denmark for their skillful help.Peer reviewe
Delivery systems for omega-3 oils
Research during the last four decades has demonstrated that oils rich in the highly polyunsaturated marine omega-3 fatty acids, EPA and DHA, have several health benefits. The positive health benefits of omega-3 fatty acids have led to increased use of omega-3 oils for functional foods. However, due to their polyunsaturated nature, omega-3 oils are highly susceptible to lipid oxidation, which decreases their nutritional value, gives rise to off-flavors, and leads to the formation of toxic aldehydes during food enrichment and digestion. Development of delivery systems, which allows food fortification with omega-3 PUFAs is a possible strategy to reduce lipid oxidation. This presentation will discuss different types of delivery systems including low and high fat emulsions and micro-encapsulated fish oil using different encapsulation techniques such as spray drying and electro spraying. It will be discussed how different emulsifiers and encapsulating materials will affect the oxidative stability of the delivery emulsion
Infra-Red Spectral Microscopy Of Standing-Wave Resonances In Single Metal-Dielectric-Metal Thin-Film Cavity
Resonantly absorbing thin films comprising periodically sub-wavelength structured metal surface, dielectric spacer, and metal ground plane are a topic of current interest with important applications. These structures are frequently described as â€metamaterialsâ€, where effective permittivity and permeability with dispersion near electric and magnetic resonances allow impedance matching to free space for maximum absorption. In this paper, we compare synchrotron-based infrared spectral microscopy of a single isolated unit cell and a periodic array, and we show that the resonances have little to do with periodicity. Instead, the observed absorption spectra of usual periodically structured thin films are best described as due to standing-wave resonances within each independent unit cell, rather than as due to effective optical constants of a metamaterial. The effect of having arrays of unit cells is mainly to strengthen the absorption by increasing the fill factor, and such arrays need not be periodic. Initial work toward applying the subject absorbers to room-Temperature bolometer arrays is presented