Active bilayer films of thermoplastic starch and polycaprolactone obtained by compression molding

Chapter 7 of the DOCTORAL THESIS "Development and characterization of corn starch films by blending with more hydrophobic compounds" by Rodrigo Ortega Toro https://riunet.upv.es/handle/10251/52521[EN] Bilayer films consisting of one layer of PCL with either one of thermoplastic starch (S) or one of thermo-plastic starch with 5% PCL (S95) were obtained by compression molding. Before compression, aqueoussolutions of ascorbic acid or potassium sorbate were sprayed onto the S or S95 layers in order to plas-ticize them and favor layer adhesion. S95 films formed bilayers with PCL with very good adhesion andgood mechanical performance, especially when potassium sorbate was added at the interface. All bilayersenhanced their barrier properties to water vapour (up to 96% compared to net starch films) and oxygen(up to 99% compared to PCL pure). Bilayers consisting of PCL and starch containing 5% PCL, with potas-sium sorbate at the interface, showed the best mechanical and barrier properties and interfacial adhesionwhile having active properties, associated with the antimicrobial action of potassium sorbate.The authors acknowledge the financial support from the Spanish Ministerio de Educacion y Ciencia throughout the project AGL2013-42989-R. Rodrigo Ortega-Toro thanks the Conselleria de Educacio de la Comunitat Valenciana for the Santiago Grisolia grant (GROSO-LIA 2012/001). Authors also thank to Electron Microscopy Service of the UPV for their technical assistance.Ortega-Toro, R.; Morey, I.; Talens Oliag, P.; Chiralt, A. (2015). Active bilayer films of thermoplastic starch and polycaprolactone obtained by compression molding. Carbohydrate Polymers. 127:282-290. https://doi.org/10.1016/j.carbpol.2015.03.080S28229012

Influence of citric acid on the properties and stability of starch-polycaprolactone based films

[EN] The influence of citric acid (CA) on structural and physicochemical properties of blend films based on corn starch and polycaprolactone (PCL) was studied. Films were obtained by melt blending of starch and PCL and compression molding. Phase separation of polymers observed by scanning electron microscope and atomic force microscope was reduced by CA incorporation. CA affected both starch and PCL crystallization as deduced from the X-ray diffraction patterns and values of melting enthalpy. Glass transition of starch was reduced by PCL incorporation, while this occurred to a greater extent in films containing CA. Obtained results point to enhanced interactions between PCL and starch chains in films with CA, although this only quantitatively benefits the film properties at a low PCL ratio. Compounding starch with small amounts of PCL, using glycerol and CA, can supply films with better functional properties than net starch films.The authors acknowledge the financial support from the Spanish Ministerio de Educacion y Ciencia throughout the projects AGL2010-20694 and AGL2013-42989-R. Rodrigo Ortega-Toro thanks the Conselleria de Educacio de la Comunitat Valenciana for the Santiago Grisolia grant. Authors also thank the Electron Microscopy Service of the UPV for their technical assistance.Ortega Toro, R.; Collazo-Bigliardi, S.; Talens Oliag, P.; Chiralt, A. (2015). Influence of citric acid on the properties and stability of starch-polycaprolactone based films. Journal of Applied Polymer Science. 133(2):1-16. doi:10.1002/app.42220S1161332Flieger, M., Kantorová, M., Prell, A., Řezanka, T., & Votruba, J. (2003). Biodegradable plastics from renewable sources. Folia Microbiologica, 48(1), 27-44. doi:10.1007/bf02931273GARCIA, M., PINOTTI, A., MARTINO, M., & ZARITZKY, N. (2004). 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Data calibration for the MASCARA and bRing instruments

Aims: MASCARA and bRing are photometric surveys designed to detect variability caused by exoplanets in stars with $m_V < 8.4$. Such variability signals are typically small and require an accurate calibration algorithm, tailored to the survey, in order to be detected. This paper presents the methods developed to calibrate the raw photometry of the MASCARA and bRing stations and characterizes the performance of the methods and instruments. Methods: For the primary calibration a modified version of the coarse decorrelation algorithm is used, which corrects for the extinction due to the earth's atmosphere, the camera transmission, and intrapixel variations. Residual trends are removed from the light curves of individual stars using empirical secondary calibration methods. In order to optimize these methods, as well as characterize the performance of the instruments, transit signals were injected in the data. Results: After optimal calibration an RMS scatter of 10 mmag at $m_V \sim 7.5$ is achieved in the light curves. By injecting transit signals with periods between one and five days in the MASCARA data obtained by the La Palma station over the course of one year, we demonstrate that MASCARA La Palma is able to recover 84.0, 60.5 and 20.7% of signals with depths of 2, 1 and 0.5% respectively, with a strong dependency on the observed declination, recovering 65.4% of all transit signals at $\delta > 0^\circ$ versus 35.8% at $\delta < 0^\circ$. Using the full three years of data obtained by MASCARA La Palma to date, similar recovery rates are extended to periods up to ten days. We derive a preliminary occurrence rate for hot Jupiters around A-stars of ${>} 0.4 \%$, knowing that many hot Jupiters are still overlooked. In the era of TESS, MASCARA and bRing will provide an interesting synergy for finding long-period (${>} 13.5$ days) transiting gas-giant planets around the brightest stars.Comment: 18 pages, 17 figures, accepted for publication in A&

El yacimiento arqueológico de El Saucedo (Talavera La Nueva, Toledo): balance y perspectivas

En este artículo presentamos una síntesis de los trabajos de investigación, conservación y difusión reali-zados en el yacimiento de b'l Saucedo hasta el presente, así como un esbozo de los planes de actuación para el futuro

Application of edible coatings to partially dehydrated pineapple for use in fruit cereal products

[EN] The present work analyzes the application method and the effectiveness of edible coatings based on caseinates or chitosan in partially dehydrated pineapple for its use in dry fruit-cereal products. Commercial breakfast cereals and partially dehydrated pineapples prepared by osmotic dehydration and vacuum impregnation were used for the experiments. Four coating application techniques, working at atmospheric pressure or applying vacuum impregnation, were used for coating the pineapple samples. Coated and uncoated samples were stored, at 20 degrees C with breakfast cereals and were subsequently analyzed weekly during 6 months. Critical water activity and critical water content for the glass transition of the cereals at 20 degrees C were estimated as 0.60 and 9.1 g water/100 g of product, respectively. Results show that the application of coatings by vacuum impregnation and sample air drying after coating, considerably extends the shelf-life of the pineapple-cereal system when caseinate based coatings are used. Chitosan based coatings are less effective to limit water vapor transfer and the critical moisture content of cereals are reached during the storage period. (c) 2012 Elsevier Ltd. All rights reserved.The authors acknowledge the financial support from the Conselleria de Educacion de la Comunidad Valenciana through Project GVPRE/2008/355 and Universitat Politecnica de Valencia through Project PAID-06-08-3242 M.J. Fabra thanks the support of Campus de Excelencia Internacional from Universitat Politecnica de Valencia.Talens Oliag, P.; Pérez-Masià, R.; Fabra Rovira, MJ.; Vargas, M.; Chiralt, A. (2012). Application of edible coatings to partially dehydrated pineapple for use in fruit cereal products. Journal of Food Engineering. 112:86-93. https://doi.org/10.1016/j.jfoodeng.2012.03.022S869311

"It has no meaning to me". How do researchers understand the effectiveness of literature searches? A qualitative analysis and preliminary typology of understandings

This study aimed to address the question: what does “effectiveness” mean to researchers in the context of literature searching for systematic reviews? We conducted a thematic analysis of responses to an e‐mail survey. Eighty‐nine study authors, whose studies met inclusion in a recent review (2018), were contacted via e‐mail and asked three questions; one directly asking the question: in literature searching, what does effective (or effectiveness in) literature searching mean to you? Thirty‐eight (46%) responses were received from diverse professional groups, including: literature searchers, systematic reviewers, clinicians and researchers. A shared understanding of what effectiveness means was not identified. Instead, five themes were developed from data: 1) effectiveness is described as a metric; 2) effectiveness is a balance between metrics; 3) effectiveness can be categorised by search purpose; 4) effectiveness is an outcome; and, 5) effectiveness is an experimental concept. We propose that these themes constitute a preliminary typology of understandings. No single definition of effectiveness was identified. The proposed typology suggests that different researchers have differing understandings of effectiveness. This could lead to uncertainty as to the aim and the purpose of literature searches and confusion about the outcomes. The typology offers a potential route for further exploration

bRing: An observatory dedicated to monitoring the β\beta Pictoris b Hill sphere transit

Aims. We describe the design and first light observations from the $\beta$ Pictoris b Ring ("bRing") project. The primary goal is to detect photometric variability from the young star $\beta$ Pictoris due to circumplanetary material surrounding the directly imaged young extrasolar gas giant planet \bpb. Methods. Over a nine month period centred on September 2017, the Hill sphere of the planet will cross in front of the star, providing a unique opportunity to directly probe the circumplanetary environment of a directly imaged planet through photometric and spectroscopic variations. We have built and installed the first of two bRing monitoring stations (one in South Africa and the other in Australia) that will measure the flux of $\beta$ Pictoris, with a photometric precision of $0.5\%$ over 5 minutes. Each station uses two wide field cameras to cover the declination of the star at all elevations. Detection of photometric fluctuations will trigger spectroscopic observations with large aperture telescopes in order to determine the gas and dust composition in a system at the end of the planet-forming era. Results. The first three months of operation demonstrate that bRing can obtain better than 0.5\% photometry on $\beta$ Pictoris in five minutes and is sensitive to nightly trends enabling the detection of any transiting material within the Hill sphere of the exoplanet

MASCARA-2 b: A hot Jupiter transiting the mV=7.6m_V=7.6 A-star HD185603

In this paper we present MASCARA-2 b, a hot Jupiter transiting the $m_V=7.6$ A2 star HD 185603. Since early 2015, MASCARA has taken more than 1.6 million flux measurements of the star, corresponding to a total of almost 3000 hours of observations, revealing a periodic dimming in the flux with a depth of $1.3\%$. Photometric follow-up observations were performed with the NITES and IAC80 telescopes and spectroscopic measurements were obtained with the Hertzsprung SONG telescope. We find MASCARA-2 b orbits HD 185603 with a period of $3.474119^{+0.000005}_{-0.000006}~\rm{days}$ at a distance of $0.057 \pm 0.006~\rm{AU}$, has a radius of $1.83 \pm 0.07~\rm{R}_{\rm{J}}$ and place a $99\%$ upper limit on the mass of $< 17~\rm{M}_{\rm{J}}$. HD 185603 is a rapidly rotating early-type star with an effective temperature of $8980^{+90}_{-130}~\rm{K}$ and a mass and radius of $1.89^{+0.06}_{-0.05}~M_\odot$, $1.60 \pm 0.06~R_\odot$, respectively. Contrary to most other hot Jupiters transiting early-type stars, the projected planet orbital axis and stellar spin axis are found to be aligned with $\lambda=0.6 \pm 4^\circ$. The brightness of the host star and the high equilibrium temperature, $2260 \pm 50~\rm{K}$, of MASCARA-2 b make it a suitable target for atmospheric studies from the ground and space. Of particular interest is the detection of TiO, which has recently been detected in the similarly hot planets WASP-33 b and WASP-19 b.Comment: 8 pages, 4 figures, Accepted for publication in A&

Enhancement of interfacial adhesion between starch and graftedpoly(epsilon-caprolactone)

[EN] The use of a modified poly(Epsilon-caprolactone) (gPCL) to enhance polymer miscibility in films based on ther-moplastic starch (S) and poly(Epsilon-caprolactone) is reported. PCL was functionalized by grafting with maleicanyhdride (MA) and/or glycidyl methacrylate (GMA) by reactive blending in a batch mixer. gPCL basedmaterials were analysed in terms of their grafting degree, structural and thermal properties. Blends basedon starch and PCL (wt. ratio 80:20) with including gPCL (0, 2.5 and 5 wt.%), as a compatibilizer, wereobtained by extrusion and compression moulding, and their structural, thermal, mechanical and bar-rier properties were investigated. Blends containing gPCL evidenced better interfacial adhesion betweenstarch and PCL domains, as deduced from both structural (XRD, FTIR, SEM) and bulk properties (DSC, TGA).Moreover, grafted PCL-based compatibilizers greatly improved functional properties of S-PCL blend films,as pointed out from mechanical performance and higher barrier properties, valuable to meet the foodpackaging requirements.The authors gratefully acknowledge the project MAREA, "Materiali Avanzati per la Ricerca ed il comparto Agroalimentare"-in the frame of National Operative Program (PON 2007-2013) and Ministerio de Economia y Competitividad (Spain) throughout the project AGL2013-42989 for their research financial support. They would like to thank the laboratory of electron microscopy "LaMEST" CNR, in the person of Maria Cristina Del Barone for the kind technical assistance in performing SEM analysis. R. Rodrigo Ortega-Toro thanks the Conselleria de Educacio de la Comunitat Valenciana for the Santiago Grisolia grant (GRISOLIA 2012/001) and to Short-Term Scientific Missions (STSM) from European Cooperation in Science and Technology (COST).Ortega-Toro, R.; Santagata, G.; D Ayala, GG.; Cerruti, P.; Talens Oliag, P.; Chiralt, A.; Malinconico, M. (2016). Enhancement of interfacial adhesion between starch and graftedpoly(epsilon-caprolactone). Carbohydrate Polymers. 147:16-27. https://doi.org/10.1016/j.carbpol.2016.03.070S162714