1,888 research outputs found
Effect of chitosan essential oil films on the storage-keeping quality of pork meat products
Edible films based on chitosan were prepared, with
and without basil or thyme essential oils, with the aim of
assessing their protective ability against lipid oxidation and
their antimicrobial activity. Chitosan films had good oxygenbarrier
properties, which were worsened by essential oil addition,
especially when the film equilibrium moisture content
increased. Due to the oxygen-barrier effect, all the films
effectively protected pork fat from oxidation, in comparison
to unprotected samples. In spite of the worsening of the
oxygen-barrier properties, the films with essential oils were
more effective than those of pure chitosan, which points to the
chemical action of specific antioxidant compounds of the oils.
Films were effective to control microbial growth in minced
pork meat, although the incorporation of essential oils did not
improve their antimicrobial activity. Throughout the storage,
the films led to colour changes in minced pork meat associated
with the conversion of myoglobin into metmyoglobin due to
the reduction of the oxygen availability.The authors acknowledge the financial support provided by the Universitat Politecnica de Valencia (PAID-06-09-2834), Generalitat Valenciana (GV/2010/082) and Ministerio de Educacion y Ciencia (AGL2010-20694). Author J. Bonilla is deeply grateful to Generalitat Valenciana for a Santiago Grisolia Grant.Bonilla Lagos, MJ.; Vargas, M.; Atarés Huerta, LM.; Chiralt Boix, MA. (2014). Effect of chitosan essential oil films on the storage-keeping quality of pork meat products. Food and Bioprocess Technology. 7(8):2443-2450. https://doi.org/10.1007/s11947-014-1329-3S2443245078ASTM D3985. (1995). Standard test method for oxygen gas transmission rate through plastic films and sheeting using a coulometric sensor. West Conshohocken: American Society for Testing and Materials.Atarés, L., Pérez-Masiá, R., & Chiralt, A. (2011). The role of some antioxidants in the HPMC film properties and lipid protection in coated toasted almonds. Journal of Food Engineering, 104, 649–656.Aureli, P., Costantini, A., & Zolea, S. (1992). Antimicrobial activity of some plant essential oils against Listeria monocytogenes. Journal of Food Protection, 55, 344–348.Baranauskiene, R., Venskutoni, S. P. R., Viskelis, P., & Dambrauskiene, E. (2003). Influence of nitrogen fertilizers on the yield and composition of thyme (Thymus vulgaris). Journal of Agricultural and Food Chemistry, 51, 7751–7758.Bonilla, J., Atarés, L., Vargas, M., & Chiralt, A. (2012a). Edible films and coatings to prevent the detrimental effect of oxygen on food quality: possibilities and limitations. Journal of Food Engineering, 110, 208–213.Bonilla, J., Atarés, L., Vargas, M., & Chiralt, A. (2012b). Effect of essential oils and homogenization conditions on properties of chitosan-based films. Food Hydrocolloids, 26, 9–16.Burt, S. (2004). Essential oils: their antibacterial properties and potential applications in foods—a review. International Journal of Food Microbiology, 94, 223–253.Burt, S. A., & Reinders, R. D. (2003). Antibacterial activity of selected plant essential oils against Escherichia coli O157:H7. Letters in Applied Microbiology, 36, 162–167.Caner, C., Vergano, P. J., & Wiles, J. L. (1998). Chitosan film mechanical and permeation properties as affected by acid, plasticizer and storage. Journal of Food Science, 63, 1049–1053.Casariego, A., Souza, B. W. S., Cerqueira, M. A., Teixeira, J. A., Cruz, L., Díaz, R., et al. (2009). Chitosan/clay ‘films properties as affected by biopolymer and clay micro/nanoparticles’ concentrations. Food Hydrocolloids, 23, 1895–1902.Devlieghere, F., Vermeiren, L., & Debevere, J. (2004). New preservation technologies: possibilities and limitations. International Dairy Journal, 14, 273–285.Di Pasqua, R., Hoskins, N., Betts, G., & Mauriello, G. (2006). Changes in membrane fatty acids composition of microbial cells induced by addiction of thymol, carvacrol, limonene, cinnamaldehyde and eugenol in the growing media. Journal of Agricultural and Food Chemistry, 54, 2745–2749.Di Pierro, P., Sorrentino, A., Mariniello, L., Giosafatto, C. V. L., & Porta, R. (2011). Chitosan/whey protein film as active coating to extend Ricotta cheese shelf-life. LWT--Food Science and Technology, 44, 2324–2327.Fabra, M. J., Talens, P., Gavara, R., & Chiralt, A. (2012). Barrier properties of sodium caseinate films as affected by lipid composition and moisture content. Journal of Food Engineering, 109(3), 372–379.Gaysinsky, S., Davidson, P. M., Bruce, B. D., & Weiss, J. (2005). Growth inhibition of E. Coli O157:H7 and Listeria monocytogenes by carvacrol and eugenol encapsulated in surfactant micelles. Journal of Food Protection, 68, 2559–2566.Govaris, A., Botsoglou, E., Sergelidis, D., & Chatzopoulou, P. D. (2011). Antibacterial activity of oregano and thyme essential oils against Listeria monocytogenes and Escherichia coli O157:H7 in feta cheese packaged under modified atmosphere. LWT - Food Science and Technology, 44, 1240–1244.Han, J. H., & Gennadios, A. (2005). Edible films and coatings: a review. In J. H. Han (Ed.), Innovations in Food Packaging (pp. 39–262). Oxford: Elsevier Academic.Kim, J., Marshall, M. R., & Wei, C. I. (1995). Antibacterial activity of some essential oil components against five foodborne pathogens. Journal of Agricultural and Food Chemistry, 43, 2839–2845.Labuza, T. P. (1980). The effect of water activity on reaction kinetics of food deterioration. Food Technology, 34, 36–41.Mancini, R. A., & Hunt, M. C. (2005). Current research in meat color. Meat Science, 71, 100–121.Moure, A., Cruz, J. M., Franco, D., Dominguez, J. M., Sineiro, J., Dominguez, H., et al. (2001). Natural antioxidants from residual sources. Food Chemistry, 72, 145–171.Rao, M. S., Chander, R., & Sharma, A. (2005). Development of shelf-stable intermediate moisture meat products using active edible chitosan coating and irradiation. Journal of Food Science, 70, 325–331.Salame, M. (1986). Barrier polymers. In M. Bakker (Ed.), The Wiley encyclopedia of packaging technology (pp. 48–54). New York: Wiley.Sánchez-González, L., González-Martínez, C., Chiralt, A., & Cháfer, M. (2010). Physical and antimicrobial properties of chitosan–tea tree essential oil composite films. Journal of Food Engineering, 98, 443–452.Sánchez-González, L., Vargas, M., González-Martínez, C., Chiralt, A., & Cháfer, M. (2011a). Use of essential oils in bioactive edible coatings. Food Engineering Reviews, 3, 1–16.Sánchez-González, L., Cháfer, M., Hernández, M., Chiralt, A., & González-Martínez, C. (2011b). Antimicrobial activity of polysaccharide films containing essential oils. Food Control, 22, 1302–1310.Seydim, A. C., & Sarikus, G. (2006). Antimicrobial activity of whey protein based edible films incorporated with oregano, rosemary and garlic essential oils. Food Research International, 39, 639–644.Shan, B., Cai, Y. Z., Sun, M., & Corke, H. (2005). Antioxidant capacity of 26 spice extracts and characterization of their phenolic constituents. Journal of Agricultural and Food Chemistry, 53, 7749–7759.Singh, B., Falahee, M. B., & Adams, M. R. (2001). Synergistic inhibition of Listeria monocytogenes by nisin and garlic extract. Food Microbioliology, 18, 133–139.Vargas, M., Albors, A., Chiralt, A., & González-Martínez, C. (2006). Quality of cold-stored strawberries as affected by chitosan–oleic acid edible coatings. Postharvest Biology and Technology, 41, 164–171.Vargas, M., Albors, A., Chiralt, A., & González-Martínez, C. (2009). Characterization of chitosan–oleic acid composite films. Food Hydrocolloids, 23, 536–547.Vargas, M., Albors, A., & Chiralt, A. (2011). Application of chitosan-sunflower oil edible films to pork meat hamburgers. Procedia Food Science, 1, 39–43.Wan, J., Wilcock, A., & Coventry, M. J. (1998). The effect of essential oils of basil on the growth of Aeromonas hydrophila and Pseudomonas fluorescens. Journal of Applied Microbiology, 84, 152–158.Zivanovic, S., Chi, S., & Draughon, F. (2005). Antimicrobial activity of chitosan films enriched with essential oils. Journal of Food Science, 70, 45–51
Data?driven model optimization for optically pumped magnetometer sensor arrays
© 2019 The Authors. Human Brain Mapping published by Wiley Periodicals, Inc. Optically pumped magnetometers (OPMs) have reached sensitivity levels that make them viable portable alternatives to traditional superconducting technology for magnetoencephalography (MEG). OPMs do not require cryogenic cooling and can therefore be placed directly on the scalp surface. Unlike cryogenic systems, based on a well-characterised fixed arrays essentially linear in applied flux, OPM devices, based on different physical principles, present new modelling challenges. Here, we outline an empirical Bayesian framework that can be used to compare between and optimise sensor arrays. We perturb the sensor geometry (via simulation) and with analytic model comparison methods estimate the true sensor geometry. The width of these perturbation curves allows us to compare different MEG systems. We test this technique using simulated and real data from SQUID and OPM recordings using head-casts and scanner-casts. Finally, we show that given knowledge of underlying brain anatomy, it is possible to estimate the true sensor geometry from the OPM data themselves using a model comparison framework. This implies that the requirement for accurate knowledge of the sensor positions and orientations a priori may be relaxed. As this procedure uses the cortical manifold as spatial support there is no co-registration procedure or reliance on scalp landmarks
Calibration Method for the Wavelength and Uniformity of Pixel Response in Photodetector Arrays
NeuroSpeech
NeuroSpeech is a software for modeling pathological speech signals considering different speech dimensions: phonation, articulation, prosody, and intelligibility. Although it was developed to model dysarthric speech signals from Parkinson's patients, its structure allows other computer scientists or developers to include other pathologies and/or measures. Different tasks can be performed: (1) modeling of the signals considering the aforementioned speech dimensions, (2) automatic discrimination of Parkinson's vs. non-Parkinson's, and (3) prediction of the neurological state according to the Unified Parkinson's Disease Rating Scale (UPDRS) score. The prediction of the dysarthria level according to the Frenchay Dysarthria Assessment scale is also provided
Physical and Antimicrobial Properties of Compression-Molded Cassava Starch-Chitosan Films for Meat Preservation
[EN] Cassava starch-chitosan films were obtained by melt bending and compression molding, using glycerol and polyethylene glycol as plasticizers. Both the starch/chitosan and the polymer/plasticizer ratios were varied in order to analyze their effect on the physical properties of the films. Additionally, the antimicrobial activity of 70:30 polymer:plasticizer films was tested in cold-stored pork meat slices as affected by chitosan content. All film components were thermally stable up to 200 A degrees C, which guaranteed their thermostability during film processing. Starch and chitosan had limited miscibility by melt blending, which resulted in heterogeneous film microstructure. Polyethylene glycol partially crystallized in the films, to a greater extent as the chitosan ratio increased, which limited its plasticizing effect. The films with the highest plasticizer ratio were more permeable to water vapor, less rigid, and less resistant to break. The variation in the chitosan content did not have a significant effect on water vapor permeability. As the chitosan proportion increased, the films became less stretchable, more rigid, and more resistant to break, with a more saturated yellowish color. The incorporation of the highest amount of chitosan in the films led to the reduction in coliforms and total aerobic counts of cold-stored pork meat slices, thus extending their shelf-life.The authors acknowledge the financial support provided by the Spanish Ministerio de Economia y Competividad (Projects AGL2013-42989-R and AGL2016-76699-R). Author Cristina Valencia-Sullca thanks the Peruvian Grant National Program (PRONABEC Grant).Valencia-Sullca, CE.; Atarés Huerta, LM.; Vargas, M.; Chiralt, A. (2018). Physical and Antimicrobial Properties of Compression-Molded Cassava Starch-Chitosan Films for Meat Preservation. Food and Bioprocess Technology. 11(7):1339-1349. https://doi.org/10.1007/s11947-018-2094-5S13391349117Alves, V. 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The Sensitivity of HAWC to High-Mass Dark Matter Annihilations
The High Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view
detector sensitive to gamma rays of 100 GeV to a few hundred TeV. Located in
central Mexico at 19 degrees North latitude and 4100 m above sea level, HAWC
will observe gamma rays and cosmic rays with an array of water Cherenkov
detectors. The full HAWC array is scheduled to be operational in Spring 2015.
In this paper, we study the HAWC sensitivity to the gamma-ray signatures of
high-mass (multi- TeV) dark matter annihilation. The HAWC observatory will be
sensitive to diverse searches for dark matter annihilation, including
annihilation from extended dark matter sources, the diffuse gamma-ray emission
from dark matter annihilation, and gamma-ray emission from non-luminous dark
matter subhalos. Here we consider the HAWC sensitivity to a subset of these
sources, including dwarf galaxies, the M31 galaxy, the Virgo cluster, and the
Galactic center. We simulate the HAWC response to gamma rays from these sources
in several well-motivated dark matter annihilation channels. If no gamma-ray
excess is observed, we show the limits HAWC can place on the dark matter
cross-section from these sources. In particular, in the case of dark matter
annihilation into gauge bosons, HAWC will be able to detect a narrow range of
dark matter masses to cross-sections below thermal. HAWC should also be
sensitive to non-thermal cross-sections for masses up to nearly 1000 TeV. The
constraints placed by HAWC on the dark matter cross-section from known sources
should be competitive with current limits in the mass range where HAWC has
similar sensitivity. HAWC can additionally explore higher dark matter masses
than are currently constrained.Comment: 15 pages, 4 figures, version to be published in PR
VAMOS: a Pathfinder for the HAWC Gamma-Ray Observatory
VAMOS was a prototype detector built in 2011 at an altitude of 4100m a.s.l.
in the state of Puebla, Mexico. The aim of VAMOS was to finalize the design,
construction techniques and data acquisition system of the HAWC observatory.
HAWC is an air-shower array currently under construction at the same site of
VAMOS with the purpose to study the TeV sky. The VAMOS setup included six water
Cherenkov detectors and two different data acquisition systems. It was in
operation between October 2011 and May 2012 with an average live time of 30%.
Besides the scientific verification purposes, the eight months of data were
used to obtain the results presented in this paper: the detector response to
the Forbush decrease of March 2012, and the analysis of possible emission, at
energies above 30 GeV, for long gamma-ray bursts GRB111016B and GRB120328B.Comment: Accepted for pubblication in Astroparticle Physics Journal (20 pages,
10 figures). Corresponding authors: A.Marinelli and D.Zaboro
Performance of the CMS Cathode Strip Chambers with Cosmic Rays
The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device
in the CMS endcaps. Their performance has been evaluated using data taken
during a cosmic ray run in fall 2008. Measured noise levels are low, with the
number of noisy channels well below 1%. Coordinate resolution was measured for
all types of chambers, and fall in the range 47 microns to 243 microns. The
efficiencies for local charged track triggers, for hit and for segments
reconstruction were measured, and are above 99%. The timing resolution per
layer is approximately 5 ns
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