2,524 research outputs found

    Protocolo para el control de calidad de envases de plástico, utilizados en la industria farmacéutica, de cosméticos y de alimentos

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    En este trabajo se evaluaron las tres características fundamentales de desempeño que debe cumplir un envase: protección, funcionalidad y motivación. Para ello, se estudiaron y evaluaron una serie de pruebas reportadas nacional e internacional- mente. Las diferentes pruebas se clasificaron en dos grandes grupos: pruebas físicas y pruebas fisicoquímicas; por otro lado, las pruebas biológicas que son fundamentales para la evaluación de la calidad de estos materiales no están incluidas en el proto- colo propuesto, puesto que no se consideran pruebas de control de calidad de rutina. Como resultado de su evaluación experimental, se desarrolló un protocolo unificado y una guía de análisis para el control de calidad fisicoquímico de rutina de los envases y materiales de plástico

    Disentangling the neurobiological bases of temporal impulsivity in Huntington's disease

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    BackgroundDespite its impact on daily life, impulsivity in Huntington's disease (HD) is understudied as a neuropsychiatric symptom. Our aim is to characterize temporal impulsivity in HD and to disentangle the white matter correlate associated with impulsivity.MethodsForty-seven HD individuals and 36 healthy controls were scanned and evaluated for temporal impulsivity using a delay-discounting (DD) task and complementary Sensitivity to Punishment and Sensitivity to Reward Questionnaire. Diffusion tensor imaging was employed to characterize the structural connectivity of three limbic tracts: the uncinate fasciculus (UF), the accumbofrontal tract (NAcc-OFC), and the dorsolateral prefrontal cortex connectig the caudate nucleus (DLPFC-cn). Multiple linear regression analyses were applied to analyze the relationship between impulsive behavior and white matter microstructural integrity.ResultsOur results revealed altered structural connectivity in the DLPC-cn, the NAcc-OFC and the UF in HD individuals. At the same time, the variability in structural connectivity of these tracts was associated with the individual differences in temporal impulsivity. Specifically, increased structural connectivity in the right NAcc-OFC and reduced connectivity in the left UF were associated with higher temporal impulsivity scores.ConclusionsThe present findings highlight the importance of investigating the spectrum of temporal impulsivity in HD. As, while less prevalent than other psychiatric features, this symptom is still reported to significantly impact the quality of life of patients and caregivers. This study provides evidence that individual differences observed in temporal impulsivity may be explained by variability in limbic frontostriatal tracts, while shedding light on the role of sensitivity to reward in modulating impulsive behavior through the selection of immediate rewards. This study investigates individual differences in temporal impulsivity by using a delay discounting task and, its relationship with white matter connectivity. Our findings reveal significant alterations in the microstructure of key tracts of interest, including the right DLPF-Ccn, bilateral uncinate fasciculus and the left accumbo-frontal tract, in individuals with HD. Furthermore, we observed that variability in the structural connectivity in specific tracts is associated with individual differences in temporal impulsivity. imag

    On positivity of Ehrhart polynomials

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    Ehrhart discovered that the function that counts the number of lattice points in dilations of an integral polytope is a polynomial. We call the coefficients of this polynomial Ehrhart coefficients, and say a polytope is Ehrhart positive if all Ehrhart coefficients are positive (which is not true for all integral polytopes). The main purpose of this article is to survey interesting families of polytopes that are known to be Ehrhart positive and discuss the reasons from which their Ehrhart positivity follows. We also include examples of polytopes that have negative Ehrhart coefficients and polytopes that are conjectured to be Ehrhart positive, as well as pose a few relevant questions.Comment: 40 pages, 7 figures. To appear in in Recent Trends in Algebraic Combinatorics, a volume of the Association for Women in Mathematics Series, Springer International Publishin

    Evaluation of the sealing capacity of MTA, IV and OZE in apical retrobturation

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    En el presente trabajo, se evaluó la capacidad de sellado del mineral de trióxido agregado (MTA), ionómero vitreo (IV) y oxido zinc eugenol (OZE) en retrobturaciones apicales. Cien piezas dentales unirradiculares, fueron divididas en 5 grupos (n=20): 1- control positivo, ápice sin sellar; 2-control negativo, ápice impermeabilizado con esmalte de uñas; 3- retrobturado con MTA; 4- retrobturado con OZE; 5- retrobturado con IV. Al finalizar los tratamientos ex vivo, las piezas fueron sometidas a la prueba de penetración de tinte, mediante sumersión en azul de metileno 2% durante 48 hs. A continuación, se realizó un corte transversal a 1 mm del extremo apical y se midió el porcentaje de tinción como medida de la capacidad de sellado de los materiales de obturación empleados. Los resultados fueron analizados con la prueba de Kruskal-Wallis, seguida por comparaciones de a pares. El porcentaje de tinción no difirió significativamente entre los tratamientos con MTA e IV, pero éstos mostraron un porcentaje significativamente menor con respecto al tratamiento con OZE. Además, no se encontraron diferencias significativas entre el tratamiento con OZE y el control positivo. Estos resultados demuestran que el IV y el MTA tienen similar capacidad de sellado en retrobturación in vitro, y que a su vez, constituyen mejores selladores que el OZE, que no demostró ser un sellador efectivo, al menos en las condiciones estudiadas.In the present work, the sealing capacity of the aggregate trioxide ore (MTA), vitreous ionomer (IV) and zinc oxide eugenol (OZE) in apical retrobturations was evaluated. One hundred unirradicular dental pieces were divided into 5 groups (n = 20): 1- positive control, unsealed apex; 2-negative control, apex waterproofed with nail polish; 3- retrobturado with MTA; 4- retrobturado with OZE; 5- retrobturado with IV. At the end of the ex vivo treatments, the pieces were subjected to the dye penetration test, by submerging in 2% methylene blue for 48 hours. Next, a cross section was made 1 mm from the apical end and the percentage of staining was measured as a measure of the sealing capacity of the sealing materials used. The results were analyzed with the Kruskal-Wallis test, followed by pairwise comparisons. The percentage of staining did not differ significantly between treatments with MTA and IV, but these showed a significantly lower percentage compared to treatment with OZE. In addition, no significant differences were found between the treatment with OZE and the positive control. These results demonstrate that IV and MTA have similar sealing capacity in retrobturation in vitro, and that in turn they constitute better sealants than OZE, which did not prove to be an effective sealant, at least under the conditions studied.Fil: Dones, Valentina. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Fisiología; ArgentinaFil: Mohn, Claudia Ester. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Fisiología; ArgentinaFil: Gualtieri, Ariel Félix. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Pinasco, Laura E,. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Sierra, Liliana Gloria. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Rodriguez, Pablo A.. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Casadoumecq, Ana Clara. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Fisiología; Argentin

    Interlaboratory study for the evaluation of three microtiter plate-based biofilm quantification methods

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    Microtiter plate methods are commonly used for biofilm assessment. However, results obtained with these methods have often been difficult to reproduce. Hence, it is important to obtain a better understanding of the repeatability and reproducibility of these methods. An interlaboratory study was performed in five different laboratories to evaluate the reproducibility and responsiveness of three methods to quantify Staphylococcus aureus biofilm formation in 96-well microtiter plates: crystal violet, resazurin, and plate counts. An inter-lab protocol was developed for the study. The protocol was separated into three steps: biofilm growth, biofilm challenge, biofilm assessment. For control experiments participants performed the growth and assessment steps only. For treatment experiments, all three steps were performed and the efficacy of sodium hypochlorite (NaOCl) in killing S. aureus biofilms was evaluated. In control experiments, on the log(10)-scale, the reproducibility SD (S-R) was 0.44 for crystal violet, 0.53 for resazurin, and 0.92 for the plate counts. In the treatment experiments, plate counts had the best responsiveness to different levels of efficacy and also the best reproducibility with respect to responsiveness (Slope/S-R=1.02), making it the more reliable method to use in an antimicrobial efficacy test. This study showed that the microtiter plate is a versatile and easy-to-use biofilm reactor, which exhibits good repeatability and reproducibility for different types of assessment methods, as long as a suitable experimental design and statistical analysis is applied.Peer reviewe

    White matter cortico-striatal tracts predict apathy subtypes in Huntington's disease

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    Apathy is the neuropsychiatric syndrome that correlates most highly with Huntington's disease progression, and, like early patterns of neurodegeneration, is associated with lesions to cortico-striatal connections. However, due to its multidimensional nature and elusive etiology, treatment options are limited. To disentangle underlying white matter microstructural correlates across the apathy spectrum in Huntington's disease. Forty-six Huntington's disease individuals (premanifest (N = 22) and manifest (N = 24)) and 35 healthy controls were scanned at 3-tesla and underwent apathy evaluation using the short-Problem Behavior Assessment and short-Lille Apathy Rating Scale, with the latter being characterized into three apathy domains, namely emotional, cognitive, and auto-activation deficit. Diffusion tensor imaging was used to study whether individual differences in specific cortico-striatal tracts predicted global apathy and its subdomains. We elucidate that apathy profiles may develop along differential timelines, with the auto-activation deficit domain manifesting prior to motor onset. Furthermore, diffusion tensor imaging revealed that inter-individual variability in the disruption of discrete cortico-striatal tracts might explain the heterogeneous severity of apathy profiles. Specifically, higher levels of auto-activation deficit symptoms significantly correlated with increased mean diffusivity in the right uncinate fasciculus. Conversely, those with severe cognitive apathy demonstrated increased mean diffusivity in the right frontostriatal tract and left dorsolateral prefrontal cortex to caudate nucleus tract. The current study provides evidence that white matter correlates associated with emotional, cognitive, and auto-activation subtypes may elucidate the heterogeneous nature of apathy in Huntington's disease, as such opening a door for individualized pharmacological management of apathy as a multidimensional syndrome in other neurodegenerative disorders

    Gravitational Waves From Known Pulsars: Results From The Initial Detector Era

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    We present the results of searches for gravitational waves from a large selection of pulsars using data from the most recent science runs (S6, VSR2 and VSR4) of the initial generation of interferometric gravitational wave detectors LIGO (Laser Interferometric Gravitational-wave Observatory) and Virgo. We do not see evidence for gravitational wave emission from any of the targeted sources but produce upper limits on the emission amplitude. We highlight the results from seven young pulsars with large spin-down luminosities. We reach within a factor of five of the canonical spin-down limit for all seven of these, whilst for the Crab and Vela pulsars we further surpass their spin-down limits. We present new or updated limits for 172 other pulsars (including both young and millisecond pulsars). Now that the detectors are undergoing major upgrades, and, for completeness, we bring together all of the most up-to-date results from all pulsars searched for during the operations of the first-generation LIGO, Virgo and GEO600 detectors. This gives a total of 195 pulsars including the most recent results described in this paper.United States National Science FoundationScience and Technology Facilities Council of the United KingdomMax-Planck-SocietyState of Niedersachsen/GermanyAustralian Research CouncilInternational Science Linkages program of the Commonwealth of AustraliaCouncil of Scientific and Industrial Research of IndiaIstituto Nazionale di Fisica Nucleare of ItalySpanish Ministerio de Economia y CompetitividadConselleria d'Economia Hisenda i Innovacio of the Govern de les Illes BalearsNetherlands Organisation for Scientific ResearchPolish Ministry of Science and Higher EducationFOCUS Programme of Foundation for Polish ScienceRoyal SocietyScottish Funding CouncilScottish Universities Physics AllianceNational Aeronautics and Space AdministrationOTKA of HungaryLyon Institute of Origins (LIO)National Research Foundation of KoreaIndustry CanadaProvince of Ontario through the Ministry of Economic Development and InnovationNational Science and Engineering Research Council CanadaCarnegie TrustLeverhulme TrustDavid and Lucile Packard FoundationResearch CorporationAlfred P. Sloan FoundationAstronom

    Defining the landscape of circular RNAs in neuroblastoma unveils a global suppressive function of MYCN

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    Circular RNAs (circRNAs) are a regulatory RNA class. While cancer-driving functions have been identified for single circRNAs, how they modulate gene expression in cancer is not well understood. We investigate circRNA expression in the pediatric malignancy, neuroblastoma, through deep whole-transcriptome sequencing in 104 primary neuroblastomas covering all risk groups. We demonstrate that MYCN amplification, which defines a subset of high-risk cases, causes globally suppressed circRNA biogenesis directly dependent on the DHX9 RNA helicase. We detect similar mechanisms in shaping circRNA expression in the pediatric cancer medulloblastoma implying a general MYCN effect. Comparisons to other cancers identify 25 circRNAs that are specifically upregulated in neuroblastoma, including circARID1A. Transcribed from the ARID1A tumor suppressor gene, circARID1A promotes cell growth and survival, mediated by direct interaction with the KHSRP RNA-binding protein. Our study highlights the importance of MYCN regulating circRNAs in cancer and identifies molecular mechanisms, which explain their contribution to neuroblastoma pathogenesis
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