12,974 research outputs found

    Neutrino masses and mixing with seesaw mechanism and universal breaking of extended democracy

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    In the framework of a minimal extension of the SM, where the only additional fields are three right-handed neutrinos, we suggest that the charged lepton, the Dirac neutrino and the right-handed Majorana neutrino mass matrices are all, to leading approximation, proportional to the democratic matrix. With the further assumption that the breaking of this extended democracy is universal for all leptonic mass matrices, a large mixing in the 2-3 sector can be obtained and is linked to the seesaw mechanism, together with the existence of a strong hierarchy in the masses of right-handed neutrinos. The structure of the resulting effective mass matrix of light neutrinos is stable against the RGE evolution, and a good fit to all solar and atmospheric neutrino data is obtained.Comment: LaTeX, 17 pages, 2 eps figures. A section on RGE evolution and a few references added; minor typos correcte

    A comparative study on the effect of different reactive compatibilizers on injection-molded pieces of bio-based high-density polyethylene/polylactide blends

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    This is the peer reviewed version of the following article: Quiles-Carrillo, L., Montanes, N., Jorda-Vilaplana, A., Balart, R. and Torres-Giner, S. (2019), A comparative study on the effect of different reactive compatibilizers on injection-molded pieces of bio-based high-density polyethylene/polylactide blends. J. Appl. Polym. Sci., 136, 47396, which has been published in final form at https://doi.org/10.1002/APP.47396. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] The present study reports on the development of binary blends consisting of bio-based high-density polyethylene (bio-HDPE) with polylactide (PLA), in the 5Âż20 wt % range, prepared by melt compounding and then shaped into pieces by injection molding. In order to enhance the miscibility between the green polyolefin and the biopolyester, different reactive compatibilizers were added during the melt-blending process, namely polyethylene grafted maleic anhydride (PE-g-MA), poly(ethylene-co-glycidyl methacrylate) (PE-co-GMA), maleinized linseed oil (MLO), and a combination of MLO with dicumyl peroxide (DCP). Among the tested compatibilizers, the dual addition of MLO and DCP provided the binary blend pieces with the most balanced mechanical performance in terms of rigidity and impact strength as well as the highest thermal stability. The fracture surface of the binary blend piece processed with MLO and DCP revealed the formation of a continuous structure in which the dispersed PLA phase was nearly no discerned in the bio-HDPE matrix. The resultant miscibility improvement was ascribed to both the high solubility and plasticizing effect of MLO on the PLA phase as well as the crosslinking effect of DCP on both biopolymers. The latter effect was particularly related to the formation of macroradicals of each biopolymer that, thereafter, led to the in situ formation of bio HDPE-co-PLA copolymers and also to the development of a partially crosslinked network in the binary blend. As a result, cost-effective and fully bio-based polymer pieces with improved mechanical strength, high toughness, and enhanced thermal resistance were obtained.This research was funded by the EU H2020 project YPACK (reference number 773872) and by the Ministry of Science, Innovation, and Universities (MICIU, project numbers MAT2017-84909-C2-2-R and AGL2015-63855-C2-1-R). Quiles-Carrillo and Torres-Giner are recipients of a FPU grant (FPU15/03812) from the Spanish Ministry of Education, Culture, and Sports (MECD) and a Juan de la Cierva contract (IJCI-2016-29675) from the MICIU, respectively.Quiles-Carrillo, L.; Montanes, N.; Jorda-Vilaplana, A.; Balart, R.; Torres-Giner, S. (2019). A comparative study on the effect of different reactive compatibilizers on injection-molded pieces of bio-based high-density polyethylene/polylactide blends. Journal of Applied Polymer Science. 136(16). https://doi.org/10.1002/APP.47396S13616Tahir, N., Bhatti, H. N., Iqbal, M., & Noreen, S. (2017). Biopolymers composites with peanut hull waste biomass and application for Crystal Violet adsorption. International Journal of Biological Macromolecules, 94, 210-220. doi:10.1016/j.ijbiomac.2016.10.013Imre, B., & PukĂĄnszky, B. (2013). Compatibilization in bio-based and biodegradable polymer blends. European Polymer Journal, 49(6), 1215-1233. doi:10.1016/j.eurpolymj.2013.01.019Quiles-Carrillo, L., Montanes, N., Lagaron, J. M., Balart, R., & Torres-Giner, S. (2018). On the use of acrylated epoxidized soybean oil as a reactive compatibilizer in injection-molded compostable pieces consisting of polylactide filled with orange peel flour. Polymer International, 67(10), 1341-1351. doi:10.1002/pi.5588Quiles-Carrillo, L., Blanes-MartĂ­nez, M. M., Montanes, N., Fenollar, O., Torres-Giner, S., & Balart, R. (2018). Reactive toughening of injection-molded polylactide pieces using maleinized hemp seed oil. European Polymer Journal, 98, 402-410. doi:10.1016/j.eurpolymj.2017.11.039Yu, L., Dean, K., & Li, L. (2006). Polymer blends and composites from renewable resources. Progress in Polymer Science, 31(6), 576-602. doi:10.1016/j.progpolymsci.2006.03.002Quiles-Carrillo, L., Montanes, N., Pineiro, F., Jorda-Vilaplana, A., & Torres-Giner, S. (2018). Ductility and Toughness Improvement of Injection-Molded Compostable Pieces of Polylactide by Melt Blending with Poly(Δ-caprolactone) and Thermoplastic Starch. Materials, 11(11), 2138. doi:10.3390/ma11112138Kumar, S., Panda, A. K., & Singh, R. K. (2011). A review on tertiary recycling of high-density polyethylene to fuel. 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Mechanical and tribological properties of polyamide 6 and high density polyethylene polyblends with and without compatibilizer. Wear, 246(1-2), 149-158. doi:10.1016/s0043-1648(00)00501-9Macosko, C. W., GuĂ©gan, P., Khandpur, A. K., Nakayama, A., Marechal, P., & Inoue, T. (1996). Compatibilizers for Melt Blending:  Premade Block Copolymers†. Macromolecules, 29(17), 5590-5598. doi:10.1021/ma9602482Wang, Y., & Hillmyer, M. A. (2001). Polyethylene-poly(L-lactide) diblock copolymers: Synthesis and compatibilization of poly(L-lactide)/polyethylene blends. Journal of Polymer Science Part A: Polymer Chemistry, 39(16), 2755-2766. doi:10.1002/pola.1254Nehra, R., Maiti, S. N., & Jacob, J. (2017). Poly(lactic acid)/(styrene-ethylene-butylene-styrene)-g-maleic anhydride copolymer/sepiolite nanocomposites: Investigation of thermo-mechanical and morphological properties. Polymers for Advanced Technologies, 29(1), 234-243. doi:10.1002/pat.4108ArĂłstegui, A., & NazĂĄbal, J. (2003). Supertoughness and critical interparticle distance dependence in poly(butylene terephthalate) and poly(ethylene-co-glycidyl methacrylate) blends. Journal of Polymer Science Part B: Polymer Physics, 41(19), 2236-2247. doi:10.1002/polb.10582Li, Z., Tan, B. H., Lin, T., & He, C. (2016). Recent advances in stereocomplexation of enantiomeric PLA-based copolymers and applications. Progress in Polymer Science, 62, 22-72. doi:10.1016/j.progpolymsci.2016.05.003Torres-Giner, S., Montanes, N., Boronat, T., Quiles-Carrillo, L., & Balart, R. (2016). Melt grafting of sepiolite nanoclay onto poly(3-hydroxybutyrate-co-4-hydroxybutyrate) by reactive extrusion with multi-functional epoxy-based styrene-acrylic oligomer. European Polymer Journal, 84, 693-707. doi:10.1016/j.eurpolymj.2016.09.057Zeng, J.-B., Li, K.-A., & Du, A.-K. (2015). Compatibilization strategies in poly(lactic acid)-based blends. RSC Advances, 5(41), 32546-32565. doi:10.1039/c5ra01655jCarbonell-Verdu, A., Samper, M. D., Garcia-Garcia, D., Sanchez-Nacher, L., & Balart, R. (2017). Plasticization effect of epoxidized cottonseed oil (ECSO) on poly(lactic acid). Industrial Crops and Products, 104, 278-286. doi:10.1016/j.indcrop.2017.04.050Garcia-Campo, M., Quiles-Carrillo, L., Masia, J., Reig-PĂ©rez, M., Montanes, N., & Balart, R. (2017). Environmentally Friendly Compatibilizers from Soybean Oil for Ternary Blends of Poly(lactic acid)-PLA, Poly(Δ-caprolactone)-PCL and Poly(3-hydroxybutyrate)-PHB. Materials, 10(11), 1339. doi:10.3390/ma10111339Ferri, J. M., Garcia-Garcia, D., SĂĄnchez-Nacher, L., Fenollar, O., & Balart, R. (2016). The effect of maleinized linseed oil (MLO) on mechanical performance of poly(lactic acid)-thermoplastic starch (PLA-TPS) blends. Carbohydrate Polymers, 147, 60-68. doi:10.1016/j.carbpol.2016.03.082Ferri, J. M., Garcia-Garcia, D., Montanes, N., Fenollar, O., & Balart, R. (2017). The effect of maleinized linseed oil as biobased plasticizer in poly(lactic acid)-based formulations. Polymer International, 66(6), 882-891. doi:10.1002/pi.5329Chen, G., Li, S., Jiao, F., & Yuan, Q. (2007). Catalytic dehydration of bioethanol to ethylene over TiO2/Îł-Al2O3 catalysts in microchannel reactors. Catalysis Today, 125(1-2), 111-119. doi:10.1016/j.cattod.2007.01.071Babu, R. P., O’Connor, K., & Seeram, R. (2013). Current progress on bio-based polymers and their future trends. Progress in Biomaterials, 2(1), 8. doi:10.1186/2194-0517-2-8Abdolrasouli, M. H., Sadeghi, G. M. M., Nazockdast, H., & Babaei, A. (2014). Polylactide/Polyethylene/Organoclay Blend Nanocomposites: Structure, Mechanical and Thermal Properties. Polymer-Plastics Technology and Engineering, 53(13), 1417-1424. doi:10.1080/03602559.2014.909477Abdolrasouli, M. H., Nazockdast, H., Sadeghi, G. M. M., & Kaschta, J. (2014). 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Formation of 3D networks in polylactic acid by adjusting the cross-linking agent content with respect to processing variables: a simple approach. Iranian Polymer Journal, 27(5), 329-337. doi:10.1007/s13726-018-0613-xZhou, L., He, H., Li, M., Huang, S., Mei, C., & Wu, Q. (2018). Enhancing mechanical properties of poly(lactic acid) through its in-situ crosslinking with maleic anhydride-modified cellulose nanocrystals from cottonseed hulls. Industrial Crops and Products, 112, 449-459. doi:10.1016/j.indcrop.2017.12.044Yang, S., Wu, Z.-H., Yang, W., & Yang, M.-B. (2008). Thermal and mechanical properties of chemical crosslinked polylactide (PLA). Polymer Testing, 27(8), 957-963. doi:10.1016/j.polymertesting.2008.08.009Garcia-Garcia, D., RayĂłn, E., Carbonell-Verdu, A., Lopez-Martinez, J., & Balart, R. (2017). Improvement of the compatibility between poly(3-hydroxybutyrate) and poly(Δ-caprolactone) by reactive extrusion with dicumyl peroxide. 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    Digital LED Pixels: Instructions for use and a characterization of their properties

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    This article details how to control light emitting diodes (LEDs) using an ordinary desktop computer. By combining digitally addressable LEDs with an off-the-shelf microcontroller (Arduino), multiple LEDs can be controlled independently and with a high degree of temporal, chromatic, and luminance precision. The proposed solution is safe (can be powered by a 5-V battery), tested (has been used in published research), inexpensive (∌ 60+60 + 2 per LED), highly interoperable (can be controlled by any type of computer/operating system via a USB or Bluetooth connection), requires no prior knowledge of electrical engineering (components simply require plugging together), and uses widely available components for which established help forums already exist. Matlab code is provided, including a ‘minimal working example’ of use suitable for use by beginners. Properties of the recommended LEDs are also characterized, including their response time, luminance profile, and color gamut. Based on these, it is shown that the LEDs are highly stable in terms of both luminance and chromaticity, and do not suffer from issues of warm-up, chromatic shift, and slow response times associated with traditional CRT and LCD monitor technology

    On the nature of the fourth generation neutrino and its implications

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    We consider the neutrino sector of a Standard Model with four generations. While the three light neutrinos can obtain their masses from a variety of mechanisms with or without new neutral fermions, fourth-generation neutrinos need at least one new relatively light right-handed neutrino. If lepton number is not conserved this neutrino must have a Majorana mass term whose size depends on the underlying mechanism for lepton number violation. Majorana masses for the fourth generation neutrinos induce relative large two-loop contributions to the light neutrino masses which could be even larger than the cosmological bounds. This sets strong limits on the mass parameters and mixings of the fourth generation neutrinos.Comment: To be published. Few typos corrected, references update

    Naturally light right-handed neutrinos in a 3-3-1 Model

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    In this work we show that light right-handed neutrinos, with mass in the sub-eV scale, is a natural outcome in a 3-3-1 model. By considering effective dimension five operators, the model predicts three light right-handed neutrinos, weakly mixed with the left-handed ones. We show also that the model is able to explain the LSND experiment and still be in agreement with solar and atmospheric data for neutrino oscillation.Comment: About 5 pages, no-figure

    MRI in multiple myeloma : a pictorial review of diagnostic and post-treatment findings

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    Magnetic resonance imaging (MRI) is increasingly being used in the diagnostic work-up of patients with multiple myeloma. Since 2014, MRI findings are included in the new diagnostic criteria proposed by the International Myeloma Working Group. Patients with smouldering myeloma presenting with more than one unequivocal focal lesion in the bone marrow on MRI are considered having symptomatic myeloma requiring treatment, regardless of the presence of lytic bone lesions. However, bone marrow evaluation with MRI offers more than only morphological information regarding the detection of focal lesions in patients with MM. The overall performance of MRI is enhanced by applying dynamic contrast-enhanced MRI and diffusion weighted imaging sequences, providing additional functional information on bone marrow vascularization and cellularity. This pictorial review provides an overview of the most important imaging findings in patients with monoclonal gammopathy of undetermined significance, smouldering myeloma and multiple myeloma, by performing a 'total' MRI investigation with implications for the diagnosis, staging and response assessment. Main message aEuro cent Conventional MRI diagnoses multiple myeloma by assessing the infiltration pattern. aEuro cent Dynamic contrast-enhanced MRI diagnoses multiple myeloma by assessing vascularization and perfusion. aEuro cent Diffusion weighted imaging evaluates bone marrow composition and cellularity in multiple myeloma. aEuro cent Combined morphological and functional MRI provides optimal bone marrow assessment for staging. aEuro cent Combined morphological and functional MRI is of considerable value in treatment follow-up

    Cell walls of the dimorphic fungal pathogens Sporothrix schenckii and Sporothrix brasiliensis exhibit bilaminate structures and sloughing of extensive and intact layers

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    This work was supported by the Fundação Carlos Chagas de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), grants E-26/202.974/2015 and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grants 229755/2013-5, Brazil. LMLB is a senior research fellow of CNPq and Faperj. NG acknowledged support from the Wellcome Trust (Trust (097377, 101873, 200208) and MRC Centre for Medical Mycology (MR/N006364/1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD
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