447 research outputs found
Searches for Atmospheric Long-Lived Particles
Long-lived particles are predicted in extensions of the Standard Model that
involve relatively light but very weakly interacting sectors. In this paper we
consider the possibility that some of these particles are produced in
atmospheric cosmic ray showers, and their decay intercepted by neutrino
detectors such as IceCube or Super-Kamiokande. We present the methodology and
evaluate the sensitivity of these searches in various scenarios, including
extensions with heavy neutral leptons in models of massive neutrinos, models
with an extra gauge symmetry, and a combination of both in a
model. Our results are shown as a function of the production rate
and the lifetime of the corresponding long-lived particles.Comment: 33 pages, 19 figures. v2: Minor changes, references added. Version
accepted for publication in JHE
New constraints on Heavy Neutral Leptons from Super-Kamiokande data
Heavy neutral leptons are predicted in many extensions of the Standard Model
with massive neutrinos. If kinematically accessible, they can be copiously
produced from kaon and pion decays in atmospheric showers, and subsequently
decay inside large neutrino detectors. We perform a search for these long-lived
particles using Super-Kamiokande multi-GeV neutrino data and derive stringent
limits on the mixing with electron, muon and tau neutrinos as a function of the
long-lived particle mass. We also present the limits on the branching ratio
versus lifetime plane, which are helpful in determining the constraints in
non-minimal models where the heavy neutral leptons have new interactions with
the Standard Model.Comment: 6 pages, 4 figures. v2: Minor changes, references added. Version
accepted for publication in EPJ
La Real Academia Greco-Latina: un discurso griego en defensa de los estudios helénicos
After rewinding the helenic studies situation in the begining of the XIX century in Spain, we comment the origin and evolution of the "Academia Latina Matritense" up to become "Real Academia Greco-latina", its projects and activities, its more remarkable members -specially Saturnino Lozano-, to finish with the edition and the retoric-stilistical study of one of Saturnino Lozano's speech writen in greek defending the helenic language and its study
Food aroma mass transport properties in renewable hydrophilic polymers
[EN] The sorption and transport properties of gliadin and chitosan films with respect to four representative food aroma components (ethyl caproate, 1-hexanol, 2-nonanone and α-pinene) have been studied under dry and wet environmental conditions. The partition coefficients (K) of the selected volatiles were also obtained using isooctane and soybean oil as fatty food simulants. The results showed that gliadin and chitosan films have very low capacities for the sorption of volatile compounds, and these capacities are influenced by the nature of the sorbate, the environmental relative humidity and the presence of glycerol as a plasticizer in the polymeric matrix. The volatile compounds also present a low partitioning in the biopolymer film/food stimulant system. Given the low levels of interaction observed with the volatiles, gliadin and chitosan films are of potential interest for the packaging of foods in which aroma is one of the most important quality attributes
Highlights
► Sorption kinetics and equilibrium partitioning of food aroma compounds in bioplastics. ► Gliadin and chitosan films show low sorption and partitioning capacities of food aroma compounds. ► Sorption and diffusion depend on volatile chemical structure, film composition and moisture. ► Great potential in packaging of foods in which aroma is an important quality attribute.This research has been supported from the Spanish Ministry of Science and Innovation through the Projects AGL2006-02176, AGL2009-08776 and FUN-C-FOOD Consolider Ingenio. The authors would like to thank A.P. Mac Cabe for critical reading of the manuscript.Balaguer, MP.; Gavara Clemente, R.; Hernández Muñoz, P. (2012). Food aroma mass transport properties in renewable hydrophilic polymers. Food Chemistry. 130(4):814-820. https://doi.org/10.1016/j.foodchem.2011.07.052S814820130
Foeniculum sanguineum Triano y A. Pujadas (Apiaceae) nueva especie del suroeste de la Región Mediterránea
Foeniculum sanguineum Triano & A. Pujadas, sp. nov., from the south western Mediterranean Region (Spain & Morocco) is described. Its characterization and a comparative study with the related species Foeniculum vulgare Mill., has been carried out through morphological, cytological, chemical and molecular analysis. F. sanguineum is distinguished primarily for its red petals, pink pollen in fresh, and red stylopod. It is a diploid species (2n= 22). A high proportion of limonene and piperitenone oxide (absent in F. vulgare) has been found in the essential oil composition of the dry fruits of F. sanguineum and a high amount (about 50 %) of α-phellandrene in its roots and stems. Phylogenetic analyses were performed using the internal transcribed spacer sequences of nuclear ribosomal DNA (ITS) and the chloroplast rbcL gene sequences. ITS analysis supports the existence of the new species, while revealing sequence divergence both at the intraspecific and at the interspecific levels. A Single-nucleotide-polymorphism (SNP) sequence divergence found in the slow evolving chloroplast gene provided additional support for the novel species characterization, for which the name Foeniculum sanguineum is proposed
Propuesta de Programa de Intervención “FTM: Familia y TOC, de la mano”
La familia es considerada como uno de los importantes sistemas que favorecen la salud y facilitan la mejora de la calidad de vida. Sin embargo, cuando su funcionamiento se altera debido a situaciones vitales estresantes, se requiere que el sistema familiar sea asistido y modificado. La mayoría de personas que convive con alguien que padece un Trastorno Obsesivo Compulsivo tienen altos niveles de malestar psicológico y presentan una amplia variedad de emociones abrumadoras siendo escasas sin embargo las intervenciones desarrolladas en este sentido. Precisamente el objetivo del programa de intervención que aquí se diseña y propone es mejorar las habilidades familiares a la hora de tratar con un afectado de TOC y, al mismo tiempo, dotar a los familiares de herramientas útiles para prevenir el desarrollo o disminuir los niveles del Síndrome del cuidador quemado. Un/a psicólogo/a y un/a coterapeuta trabajarán junto a un grupo de familiares durante dos meses realizando distintas actividades para cumplir los objetivos del programa. Para estimar su eficacia esperada, se utilizarán cuestionarios y entrevistas. <br /
Reversible Covalent Immobilization of Cinnamaldehyde on Chitosan Films via Schiff Base Formation and Their Application in Active Food Packaging
[EN] In this work, cinnamaldehyde was reversibly anchored to chitosan films via imino-covalent bonding. The Schiff base was synthesized in solid phase employing neutralized chitosan films immersed in acidified 95 % (v/v) ethanolic solution in which the aldehyde was dissolved. The substitution degree (%) of cinnamaldehyde to the amine group was close to 70 %. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) analysis revealed the formation of the chitosan-cinnamaldehyde Schiff base. The hydrolysis of the imino bond and subsequent release of cinnamaldehyde were studied after the films had been subjected to different combinations of temperature/time treatments simulating food preservation methods. The amount of aldehyde that remained covalently attached to the films was monitored by ATR-FTIR, and the substitution degree was determined by elemental analysis. Surface contact angle and colour parameters of cinnamaldehyde-imine-chitosan films and these films subjected to different treatments were also evaluated. The antimicrobial properties of chitosan-Schiff base films were tested in vitro against Staphylococcus aureus and Escherichia coli and in milk inoculated with Listeria monocytogenes. The antimicrobial activity varied depending on the treatment applied and consequently the degree of imino bond hydrolysis achieved and cinnamaldehyde released. Films of Schiff base-chitosan derivative subjected to different time/temperature treatments inhibited the growth of L. monocytogenes for 12 days under refrigeration conditions, which may extend the microbiological shelf life of such products. Sensory analysis of milk in contact with the films showed that a cinnamon smell does not cause any rejection among potential consumers. These novel films could be used in the design of antimicrobial food packaging and in various other technological areas where sustained-release systems are requiredThe authors wish to thank the financial support provided by the Spanish Ministry of Science and Innovation (project AGL2012-39920-C03-01) and Spanish Research Council (CSIC, JAE-Predoc L.H. fellowship).Higueras-Contreras, L.; Lopez-Carballo, G.; Gavara Clemente, R.; Hernández-Muñoz, P. (2015). Reversible Covalent Immobilization of Cinnamaldehyde on Chitosan Films via Schiff Base Formation and Their Application in Active Food Packaging. Food and Bioprocess Technology. 8(3):526-538. https://doi.org/10.1007/s11947-014-1421-8S52653883Abreu, F. O., Oliveira, E. F., Paula, H. C., & de Paula, R. (2012). Chitosan/cashew gum nanogels for essential oil encapsulation. Carbohydrate Polymers, 89(4), 1277–1282.Balaguer, M. P., Gómez-Estaca, J., Gavara, R., & Hernández-Muñoz, P. (2011a). Biochemical properties of bioplastics made from wheat gliadins cross-linked with cinnamaldehyde. Journal of Agricultural and Food Chemistry, 59(24), 13212–13220.Balaguer, M. P., Gómez-Estaca, J., Gavara, R., & Hernández-Muñoz, P. (2011b). Functional properties of bioplastics made from wheat gliadins modified with cinnamaldehyde. Journal of Agricultural and Food Chemistry, 59(12), 6689–6695.Belletti, N., Lanciotti, R., Patrignani, F., & Gardini, F. (2008). Antimicrobial efficacy of citron essential oil on spoilage and pathogenic microorganisms in fruit-based salads. Journal of Food Science, 73(7), M331–M338.Burt, S. (2004). Essential oils: their antibacterial properties and potential applications in foods—a review. International Journal of Food Microbiology, 94(3), 223–253.Cocchiara, J., Lalko, J., Lapczynski, A., Letizia, C. S., & Api, A. M. (2005). Fragrance material review on cinnamaldehyde. Food and Chemical Toxicology, 43(6), 867–923.Coma, V., Martial-Gros, A., Garreau, S., Copinet, A., Salin, F., & Deschamps, A. (2002). Edible antimicrobial films based on chitosan matrix. Journal of Food Science, 67(3), 1162–1169.Damodaran, S., & Kinsella, J. E. (1980). Flavor protein interactions. Binding of carbonyls to bovine serum-albumin: thermodynamic and conformational effects. Journal of Agricultural and Food Chemistry, 28(3), 567–571.dos Santos, J. E., Dockal, E. R., & Cavalheiro, E. T. G. (2005). Synthesis and characterization of Schiff bases from chitosan and salicylaldehyde derivatives. Carbohydrate Polymers, 60(3), 277–282.Doyle, M. P., & Beuchat, L. R. (2007). Food microbiology: fundamentals and frontiers. Washington: ASM Press.Fleming, D. W., Cochi, S. L., MacDonald, K. L., Brondum, J., Hayes, P. S., Plikaytis, B. D., Holmes, M. B., Audurier, A., Broome, C. V., & Reingold, A. L. (1985). Pasteurized milk as a vehicle of infection in an outbreak of listeriosis. New England Journal of Medicine, 312(7), 404–407.Foster, L. J. R., & Butt, J. (2011). Chitosan films are not antimicrobial. Biotechnology Letters, 33(2), 417–421.Gallstedt, M., & Hedenqvist, M. S. (2006). Packaging-related mechanical and barrier properties of pulp-fiber-chitosan sheets. Carbohydrate Polymers, 63(1), 46–53.Gill, A., & Holley, R. (2004). Mechanisms of bactericidal action of cinnamaldehyde against Listeria monocytogenes and of eugenol against L. monocytogenes and Lactobacillus sakei. Applied and Environmental Microbiology, 70(10), 5750–5755.Guinesi, L. S., & Cavalheiro, E. T. G. (2006). Influence of some reactional parameters on the substitution degree of biopolymeric Schiff bases prepared from chitosan and salicylaldehyde. Carbohydrate Polymers, 65(4), 557–561.Guo, Z. Y., Xing, R. E., Liu, S., Zhong, Z. M., Ji, X., Wang, L., & Li, P. C. (2007). Antifungal properties of Schiff bases of chitosan, N-substituted chitosan and quaternized chitosan. Carbohydrate Research, 342(10), 1329–1332.Gutierrez, J., Barry-Ryan, C., & Bourke, R. (2008). The antimicrobial efficacy of plant essential oil combinations and interactions with food ingredients. International Journal of Food Microbiology, 124(1), 91–97.Higueras, L., López-Carballo, G., Cerisuelo, J. P., Gavara, R., & Hernández-Muñoz, P. (2013). Preparation and characterization of chitosan/HP-beta-cyclodextrins composites with high sorption capacity for carvacrol. Carbohydrate Polymers, 97(2), 262–268.Holley, R. A., & Patel, D. (2005). Improvement in shelf-life and safety of perishable foods by plant essential oils and smoke antimicrobials. Food Microbiology, 22(4), 273–292.Hosseini, S., Zandi, M., Rezaei, M., & Farahmandghavi, F. (2013). Two-step method for encapsulation of oregano essential oil in chitosan nanoparticles: preparation, characterization and in vitro release study. Carbohydrate Polymers, 95(1), 50–56.Huang, Z.H., Wan, D.C. & Huang, J.L. (2001). Hydrolysis of Schiff bases promoted by UV light. Chemistry Letters, (7), 708–709.Inukai, Y., Chinen, T., Matsuda, T., Kaida, Y., & Yasuda, S. J. (1998). Selective separation of germanium (IV) by 2,3-dihydroxypropylchitosan resin. Analytica Chimica Acta, 371(2–3), 187–193.Ji, C., & Shi, J. (2013). Thermal-crosslinked porous chitosan scaffolds for soft tissue engineering applications. Materials Science and Engineering: C, 33(7), 3780–3785.Jin, X., Wang, J., & Bai, J. (2009). Synthesis and antimicrobial activity of the Schiff base from chitosan and citral. Carbohydrate Research, 344(6), 825–829.Junttila, J. R., Niemela, S. I., & Hirn, J. (1988). Minimum growth temperatures of Listeria monocytogenes and non-haemolytic Listeria. Journal of Applied Bacteriology, 65(4), 321–327.Kasaai, M. R., Arul, J., Chin, S. L., & Charlet, G. (1999). The use of intense femtosecond laser pulses for the fragmentation of chitosan. Journal of Photochemistry and Photobiology, A: Chemistry, 120(3), 201–205.Kirdant, A. S., Shelke, V. A., Shankarwar, S. G., Shankarwar, A. G., & Chondhekar, T. K. (2011). Kinetic study of hydrolysis of N-salicylidene-m-methyl aniline spectrophotomerically. Journal of Chemical and Pharmaceutical Research, 3(4), 790–796.Kuhn, J., Considine, T., & Singh, H. (2006). Interactions of milk proteins and volatile flavor compounds: implications in the development of protein foods. Journal of Food Science, 71(5), R72–R82.Li, X., Shao, T., Shi, Q., & Hu, M. (2013). A diaryl Schiff base as a photo- and pH-responsive bifunctional molecule. RSC Advances, 3(45), 22877–22881.Lovett, J., Francis, D. W., & Hunt, J. M. (1987). Listeria monocytogenes in raw milk: detection, incidence, and pathogenicity. Journal of Food Protection, 50(3), 188–192.Mohamad, A. (2013). Reactivity of base catalysed hydrolysis of 2-pyridinylmethylene-8-quinolinyl-Schiff base iron(II) iodide complexes: solvent effects. Chemické zvesti, 67(4), 464–476.Muhamad, S. G. (2011). First photolysis of benzidine Schiff base in non aqueous solvents. International Journal of Chemistry, 1(3), 142–145.Muriel-Galet, V., López-Carballo, G., Gavara, R., & Hernández-Muñoz, P. (2012). Antimicrobial food packaging film based on the release of LAE from EVOH. International Journal of Food Microbiology, 157(2), 239–244.Nazzaro, F., Fratianni, F., De Martino, L., Coppola, R., & De Feo, V. (2013). Effect of essential oils on pathogenic bacteria. Pharmaceuticals, 6(12), 1451–1474.Renault, F., Sancey, B., & Crini, G. (2009). Chitosan for coagulation/flocculation processes—an eco-friendly approach. European Polymer Journal, 45(5), 1337–1348.Sashiwa, H., & Aiba, S. I. (2004). Chemically modified chitin and chitosan as biomaterials. Progress in Polymer Science, 29(9), 887–908.Shahidi, F., Arachchi, J. K. V., & Jeon, Y. J. (1999). Food applications of chitin and chitosans. Trends in Food Science & Technology, 10(2), 37–51.Vallapa, N., Wiarachai, O., Thongchul, N., Pan, J. S., Tangpasuthadol, V., Kiatkamjornwong, S., & Hoven, V. P. (2011). Enhancing antibacterial activity of chitosan surface by heterogeneous quaternization. Carbohydrate Polymers, 83(2), 868–875.Wang, J. T., Lian, Z. R., Wang, H. D., Jin, X. X., & Liu, Y. J. (2012). Synthesis and antimicrobial activity of Schiff base of chitosan and acylated chitosan. Journal of Applied Polymer Science, 123(6), 3242–3247.Zivanovic, S., Chi, S., & Draughon, A. F. (2005). Antimicrobial activity of chitosan films enriched with essential oils. Journal of Food Science, 70(1), M45–M51
Antimicrobial Effectiveness of Lauroyl Arginate Incorporated into Ethylene Vinyl Alcohol Copolymers to Extend the Shelf-Life of Chicken Stock and Surimi Sticks
[EN] This study was designated to determine the antimicrobial effect of ethyl-N-alpha-dodecanoyl-l-arginate hydrochloride (LAE) incorporated into ethylene vinyl alcohol copolymers (EVOH) films on chicken stock and ready-to-eat surimi sticks. Firstly, the effect of LAE against Listeria monocytogenes and Escherichia coli was studied by using flow cytometry and scanning electron microscopy. Next, film-forming solutions of ethylene vinyl alcohol copolymers EVOH29 and EVOH44 (29 and 44 % molar percentage of ethylene, respectively) containing 0, 5 and 10 % w/w of LAE were cast into films. Several experiments were conducted to determine the antimicrobial activity of the films in vitro and also in vivo with the above-mentioned food products. The outcome of the tests showed a high impact on the viability of bacteria treated with LAE, with dramatic damage to the membrane. The films were able to inhibit the microbiota of the food products studied for 10 days under storage at 4 A degrees C, showing a significant antibacterial effect against L. monocytogenes and E. coli. These films show great potential as systems for sustained release of active molecules to improve the safety and quality of packaged food products.The authors acknowledge the financial support of the Spanish Ministry of Economy and Competitiveness, project AGL2012-39920-C03-01, and fellowship funding for V. M.-G.Muriel Galet, V.; Lopez-Carballo, G.; Gavara Clemente, R.; Hernández-Muñoz, P. (2015). Antimicrobial Effectiveness of Lauroyl Arginate Incorporated into Ethylene Vinyl Alcohol Copolymers to Extend the Shelf-Life of Chicken Stock and Surimi Sticks. Food and Bioprocess Technology. 8(1):208-216. https://doi.org/10.1007/s11947-014-1391-xS20821681Adams MR & Moss MO (2008) Food microbiology. The Royal Society of Chemistry Cambrigde, UKAppendini, P., & Hotchkiss, J. H. (2002). Review of antimicrobial food packaging. Innovative Food Science and Emerging Technologies, 3(2), 113–126.Bakal G & Diaz A (2005) The lowdown on lauric arginate. Food quality(Feb./March), 60-61.Fellows PJ (2009) Food processing technology: principle and practice. Third edn.Guo, M., Jin, T., Wang, L., Scullen, O. J., & Sommers, C. (2014). Antimicrobial films and coatings for inactivation of Listeria innocua on ready-to-eat deli turkey meat. Food Control, 40, 64–70.Han JH (2013) Innovations in food packaging.Hawkins, D. R., Rocabayera, X., Ruckman, S., Segret, R., & Shaw, D. (2009). Metabolism and pharmacokinetics of ethyl N-alpha-lauroyl-L-arginate hydrochloride in human volunteers. Food and Chemical Toxicology, 47(11), 2711–2715.Higueras, L., Lopez Carballo, G., Hernandez Munoz, P., Gavara, R., Rollini, M., López Carballo, G., & Hernández Muñoz, P. (2013). Development of a novel antimicrobial film based on chitosan with LAE (ethyl-N)-dodecanoyl-l-arginate) and its application to fresh chicken. International Journal of Food Microbiology, 165(3), 339–345.Kilcast D & Subramaniam P (2000) The stability and shelf-life of food. Woodhead Publishing CambridgeMuriel-Galet, V., Lopez-Carballo, G., Gavara, R., & Hernandez-Munoz, P. (2012). Antimicrobial food packaging film based on the release of LAE from EVOH. International Journal of Food Microbiology, 157(2), 239–244.Muriel-Galet, V., López-Carballo, G., Hernández-Muñoz, P., & Gavara, R. (2013). Characterization of ethylene-vinyl alcohol copolymer containing lauril arginate (LAE) as material for active antimicrobial food packaging. Food Packaging and Shelf Life, 1, 10–17.Rodriguez, E., Seguer, J., Rocabayera, X., & Manresa, A. (2004). Cellular effects of monohydrochloride of L-arginine, N-alpha-lauroyl ethylester (LAE) on exposure to Salmonella typhimurium and Staphylococcus aureus. Journal of Applied Microbiology, 96(5), 903–912.Sallam, & Ibrahim, K. (2007). Antimicrobial and antioxidant effects of sodium acetate, sodium lactate, and sodium citrate in refrigerated sliced salmon. Food Control, 18(5), 566–575.Sung, S.-Y., Sin, L. T., Tee, T.-T., Bee, S.-T., Rahmat, A. R., Rahman, W. A. W. A., Tan, A.-C., & Vikhraman, M. (2013). Antimicrobial agents for food packaging applications. Trends in Food Science & Technology, 33(2), 110–123.Theinsathid, P., Visessanguan, W., Kruenate, J., Kingcha, Y., & Keeratipibul, S. (2012). Antimicrobial activity of lauric arginate-coated polylactic acid films against Listeria monocytogenes and Salmonella typhimurium on cooked sliced ham. Journal of Food Science, 77(2), M142–149
Novel antimicrobial zein film for controlled release of lauroyl arginate (LAE)
Novel antimicrobial biopolymer films based on the incorporation of ethyl-Nα-dodecanoyl-l-arginate hydrochloride (LAE) in zein matrices were manufactured and characterized as materials for LAE controlled released applications such as active food packaging. Characterization of the films’ functional properties revealed that incorporation of LAE (5 and 10%) in the biopolymer matrix did not cause substantial changes in morphological, optical, thermal, mechanical and barrier properties.
As the mechanism of action of these films is mainly based on release of the antimicrobial, this process was characterized when the active biofilms were exposed to three food simulants (water, 3% acetic acid, and 10% alcohol) at three temperatures (4, 23, and 37 °C). The data obtained revealed that, with the exception of exposure to water at 4 °C which achieved a release of more than 80% of the LAE incorporated, the agent was almost completely extracted in all conditions. Release of LAE was faster at higher temperatures, and the diffusion coefficient values varied according to the Arrhenius law, and increased with temperature. Antibacterial activity of films was assayed against Listeria monocytogenes and Escherichia coli. Zein films with 5% LAE produced 2.02 and 3.07 log reduction against L. monocytogenes and E. coli, respectively, after 5 days of storage at 4 °C. Greater antibacterial activity was observed with films containing 10% LAE (5 log reduction) at 37 °C. This work highlighted that LAE incorporation in a packaging film constructed with renewable polymer materials offers an interesting and efficient hurdle for control of bacterial contamination in foods.The authors acknowledge the financial support of the Spanish Ministry of Economy and Competitiveness, projects AGL2012-39920-C03-01. M.K. thanks the Ministry of Sciences, Research and Technology of Iran for her grant. I.D. thanks the CSIC for her postdoctoral contract (JAE-DOC).Peer reviewe
Un modelo computacional de simulación de la dispersión de contaminantes en agua
En este Trabajo de Fin de Grado se han analizado varios modelos de dispersión para solutos pasivos en flujos transitorios de agua, familiarizándose así con algunas de las técnicas utilizadas en la resolución de este tipo de problemas. Para ello, previamente se ha estudiado la formulación del problema del transporte de un soluto pasivo en agua y realizado un análisis de sensibilidad al esquema numérico y malla de cálculo. Por último se han estudiado algunas técnicas de simulación y realizado un análisis de sensibilidad al modelo de dispersión
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