274 research outputs found

    Sharp extensions and algebraic properties for solution families of vector-valued differential equations

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    In this paper we show the unexpected property that extension from local to global without loss of regularity holds for the solutions of a wide class of vector-valued differential equations, in particular for the class of fractional abstract Cauchy problems in the subdiffusive case. The main technique is the use of the algebraic structure of these solutions, which are defined by new versions of functional equations defining solution families of bounded operators. The convolution product and the double Laplace transform for functions of two variables are useful tools which we apply also to extend these solutions. Finally we illustrate our results with different concrete examples

    On well-posedness of vector-valued fractional differential-difference equations

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    We develop an operator-theoretical method for the analysis on well posedness of partial differential-difference equations that can be modeled in the form (*) {Delta(alpha) u(n) = Au(n + 2) + f(n, u(n)), n is an element of N-0, 1 < alpha <= 2; u(0) = u(0); u(1) = u(1); where A is a closed linear operator defined on a Banach space X. Our ideas are inspired on the Poisson distribution as a tool to sampling fractional differential operators into fractional differences. Using our abstract approach, we are able to show existence and uniqueness of solutions for the problem (*) on a distinguished class of weighted Lebesgue spaces of sequences, under mild conditions on sequences of strongly continuous families of bounded operators generated by A, and natural restrictions on the nonlinearity f. Finally we present some original examples to illustrate our results

    Gait stability at early stages of multiple sclerosis using different data sources

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    Background: People at early stages of multiple sclerosis have subtle balance problems that may affect gait stability. However, differences in methods of determining stability such as sensor type and placements, may lead to different results and affect their interpretation when comparing to controls and other studies. Questions: Do people with multiple sclerosis (PwMS) exhibit lower gait stability? Do location and type of data used to calculate stability metrics affect comparisons? Methods: 30 PwMS with no walking impairments as clinically measured and 15 healthy controls walked on a treadmill at 1.2 ms−1 while 3D acceleration data was obtained from sacrum, shoulder and cervical markers and from an accelerometer placed at the sacrum. The local divergence exponent was calculated for the four data sources. An ANOVA with group (multiple sclerosis and control) and data source as main factors was used to determine the effect of disease, data source and their interaction on stability metrics. Results: PwMS walked with significantly less stability according to all sensors (no interaction). A significant effect of data source on stability was also found, indicating that the local divergence exponent derived from sacrum accelerometer was lower than that derived from the other 3 sensor locations. Significance: PwMS with no evident gait impairments are less stable than healthy controls when walking on a treadmill. Although different data sources can be used to determine MS-related stability deterioration, a consensus about location and data source is needed. The local divergence exponent can be a useful measure of progression of gait instability at early stages of MS

    Well-posedness for degenerate third order equations with delay and applications to inverse problems

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    [EN] In this paper, we study well-posedness for the following third-order in time equation with delay <disp-formula idoperators defined on a Banach space X with domains D(A) and D(B) such that t)is the state function taking values in X and u(t): (-, 0] X defined as u(t)() = u(t+) for < 0 belongs to an appropriate phase space where F and G are bounded linear operators. Using operator-valued Fourier multiplier techniques we provide optimal conditions for well-posedness of equation (0.1) in periodic Lebesgue-Bochner spaces Lp(T,X), periodic Besov spaces Bp,qs(T,X) and periodic Triebel-Lizorkin spaces Fp,qs(T,X). A novel application to an inverse problem is given.The first, second and third authors have been supported by MEC, grant MTM2016-75963-P. The second author has been supported by AICO/2016/30. The fourth author has been supported by MEC, grant MTM2015-65825-P.Conejero, JA.; Lizama, C.; Murillo-Arcila, M.; Seoane Sepúlveda, JB. (2019). Well-posedness for degenerate third order equations with delay and applications to inverse problems. Israel Journal of Mathematics. 229(1):219-254. https://doi.org/10.1007/s11856-018-1796-8S2192542291K. Abbaoui and Y. Cherruault, New ideas for solving identification and optimal control problems related to biomedical systems, International Journal of Biomedical Computing 36 (1994), 181–186.M. Al Horani and A. Favini, Perturbation method for first- and complete second-order differential equations, Journal of Optimization Theory and Applications 166 (2015), 949–967.H. Amann, Operator-valued Fourier multipliers, vector-valued Besov spaces, and applications, Mathematische Nachrichten 186 (1997), 5–56.U. A. Anufrieva, A degenerate Cauchy problem for a second-order equation. A wellposedness criterion, Differentsial’nye Uravneniya 34 (1998), 1131–1133; English translation: Differential Equations 34 (1999), 1135–1137.W. Arendt and S. Bu, The operator-valued Marcinkiewicz multiplier theorem and maximal regularity, Mathematische Zeitschrift 240 (2002), 311–343.W. Arendt and S. Bu, Operator-valued Fourier multipliers on periodic Besov spaces and applications, Proceedings of the Edinburgh Mathematical Society 47 (2004), 15–33.W. Arendt, C. Batty and S. Bu, Fourier multipliers for Holder continuous functions and maximal regularity, Studia Mathematica 160 (2004), 23–51.V. Barbu and A. Favini, Periodic problems for degenerate differential equations, Rendiconti dell’Istituto di Matematica dell’Università di Trieste 28 (1996), 29–57.A. Bátkai and S. Piazzera, Semigroups for Delay Equations, Research Notes in Mathematics, Vol. 10, A K Peters, Wellesley, MA, 2005.S. Bu, Well-posedness of second order degenerate differential equations in vector-valued function spaces, Studia Mathematica 214 (2013), 1–16.S. Bu and G. Cai, Periodic solutions of third-order degenerate differential equations in vector-valued functional spaces, Israel Journal of Mathematics 212 (2016), 163–188.S. Bu and G. Cai, Well-posedness of second-order degenerate differential equations with finite delay in vector-valued function spaces, Pacific Journal of Mathematics 288 (2017), 27–46.S. Bu and Y. Fang, Periodic solutions of delay equations in Besov spaces and Triebel–Lizorkin spaces, Taiwanese Journal of Mathematics 13 (2009), 1063–1076.S. Bu and J. Kim, Operator-valued Fourier multipliers on periodic Triebel spaces, Acta Mathematica Sinica 21 (2005), 1049–1056.G. Cai and S. Bu, Well-posedness of second order degenerate integro-differential equations with infinite delay in vector-valued function spaces, Mathematische Nachrichten 289 (2016), 436–451.R. Chill and S. Srivastava, Lp-maximal regularity for second order Cauchy problems, Mathematische Zeitschrift 251 (2005), 751–781.R. Denk, M. Hieber and J. 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Pospieszalska, Well-posedness and exponential decay of the energy in the nonlinear Moore-Gibson-Thomson equation arising in high intensity ultrasound, Mathematical Models & Methods in Applied Sciences 22 (2012), 1250035.V. Keyantuo and C. Lizama, Fourier multipliers and integro-differential equations in Banach spaces, Journal of the London Mathematical Society 69 (2004), 737–750.V. Keyantuo and C. Lizama, Maximal regularity for a class of integro-differential equations with infinite delay in Banach spaces, Studia Mathematica 168 (2005), 25–50.V. Keyantuo, C. Lizama and V. Poblete, Periodic solutions of integro-differential euations in vector-valued function spaces, Journal of Differential Equations 246 (2009), 1007–1037.C. Lizama, Fourier multipliers and periodic solutions of delay equations in Banach spaces, Journal of Mathematical Analysis and Applications 324 (2006), 921–933.C. Lizama and V. 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    Efectos del ejercicio excéntrico en la arquitectura muscular en adultos: una revisión sistemática

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    The purpose of this systematic review was to determine the effects of eccentric training on muscle architecture in the adult population. Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) statements were followed using keywords associated with architecture muscular and eccentric training. Four databases were used: PubMed, Scopus, SPORTDiscus and Web of Science. Methodological quality was assessed using the PEDro scale. A total of 1260 articles were retrieved, 18 included in this review. The parameters most frequently evaluated in the studies consulted were pennation angle (PA), fascicle length (FL), and muscle thickness (MT). These were assessed mainly in lower limb muscles such as biceps femoris long head (BFlh), vastus lateralis (VL), medial gastrocnemius (MG) and lateral gastrocnemius (LG), respectively. Eccentric training for at least four weeks generates adaptations in these parameters, mainly by increasing MT with FL and decreasing PA, determining muscle function. These results provide evidence on the effects of eccentric training on muscle architecture, which could be helpful to prevent injuries and favor muscle recovery processesEl propósito de esta revisión sistemática fue determinar los efectos del entrenamiento excéntrico sobre la arquitectura muscular en la población adulta. Se siguieron las recomendaciones del Ìtems de referencia para publicar Revisiones Sistemáticas y Metaanálisis (PRISMA) utilizando palabras clave asociadas con la arquitectura muscular y el entrenamiento excéntrico en cuatro bases de datos: PubMed, Scopus, SPORTDiscus y Web of Science. La calidad metodológica se evaluó mediante la escala PEDro. Se encontró un total de 1260 artículos, del los cuales, 18 fueron incluidos en esta revisión. Los parámetros más frecuentemente evaluados en los estudios fueron el ángulo de penación (AP), la longitud del fascículo (LF) y el grosor muscular (Gm). Estos fueron evaluados principalmente en músculos de los miembros inferiores como la cabeza larga del bíceps femoral (CLBf), el vasto lateral (VL), el gastrocnemio medial (GM) y el gastrocnemio lateral (GL), respectivamente. El entrenamiento excéntrico durante al menos cuatro semanas genera adaptaciones en estos parámetros, principalmente aumentando el GM con la LF y disminuyendo el AP, determinando de esta manera la función muscular. Estos resultados aportan evidencias sobre los efectos del entrenamiento excéntrico en la arquitectura muscular, que podrían ser útiles para prevenir lesiones y favorecer los procesos de recuperación muscula

    Carotenoids from persimmon juice processing

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    [EN] The aim of this study was the use and revalorization of two persimmon by-products A and B generated in the juice production process. The by-product B resulting from a pectinase enzymatic treatment of peels and pulp to optimize juice extraction was especially suitable for recovery of valuable bioactive carotenoids. The extraction solvents and solvent combinations used were: ethanol, acetone, ethanol/acetone (50:50 v/v) and ethanol/ acetone/hexane (25:25:50 v/v/v). HPLC-DAD analysis detected and identified a total of nine individual carotenoids namely violaxanthin, neoxanthin, antheraxanthin, lutein, zeaxanthin, ß-cryptoxanthin 5,6-epoxide, ß-cryptoxanthin, ¿-carotene, and ß-carotene. ß-cryptoxanthin and ß-carotene represented 49.2% and 13.2% of the total carotenoid content (TCC) in the acetone extract from by-product B. TCC contributed greatly to antioxidant activity of acetone extract derived from this by-product. Pectinase enzymatic treatment of persimmon peels and pulp followed by absolute acetone extraction of carotenoids could be an efficient method to obtain a rich extract in these compounds that could be used as nutraceutical ingredient.This study was supported by Ministerio de Ciencia, Innovacion y Universidades through the funded project 'Simbiosis industrial en el aprovechamiento integral del caqui (Diospyros kaki); Ejemplo de bioeconomia' (CTM2017-88978-R). Sara Gea-Botella thanks the Agencia Estatal de Investigacion la Ayuda para la Formacion de Doctores en Empresas "Doctorados Industriales" (DI-16-08465) through the R+D+i project entitled 'Evaluacion in vitro e in vivo de un extracto procedente de subproductos de la industrializacion del caqui'. The authors wish to thank Mitra Sol Technologies S.L. the given technical assistance.Gea-Botella, S.; Agulló, L.; Martí, N.; Martínez-Madrid, M.; Lizama Abad, V.; Martín-Bermudo, F.; Berná, G.... (2021). Carotenoids from persimmon juice processing. Food Research International. 141:1-8. https://doi.org/10.1016/j.foodres.2020.109882S1814

    Fleas of black rats (Rattus rattus) as reservoir host of Bartonella spp. In Chile

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    Rattus rattus is a widely distributed, invasive species that presentsan important role in disease transmission, either directly or through vectorarthropods such as fleas. These black rats can transmit a wide variety of pathogens, including bacteria of the genus Bartonella, which can cause diseases in humans and animals. In Chile, no data are available identifying fleas from synanthropic rodents as Bartonella vectors. The aim of this study was to investigate the prevalence of Bartonella spp. in the fleas of R. rattus in areas with different climate conditions and featuring different human population densities. In all, 174 fleas collected from 261 R. rattus captured from 30 localities with different human densities (cities, villages, and wild areas) across five hydrographic zones of Chile (hyper-arid, arid, semi-arid, sub-humid, and hyper-humid) were examined. Bartonella spp. presence was determined through polymerase chain reaction, using gltA and rpoB genes, which were concatenated to perform a similarity analysis with BLAST and phylogenetic analysis.Results: Overall, 15 fleas species were identified; Bartonella gltA and rpoB fragments were detected in 21.2% (37/174) and 19.5% (34/174) of fleas, respectively. A total of 10 of the 15 fleas species found were positive for Bartonella DNA. Leptopsylla segnis was the most commonly collected flea species (n = 55), and it also presented a high prevalence of Bartonella DNA (P% = 34.5%). The highest numbers of fleas of this species were collected in villages of the arid zone. There were no seasonal differences in the prevalence of Bartonella DNA. The presence of Bartonella DNA in fleas was recorded in all hydrographic areas, and the arid zone presented the highest prevalence of this species. Regarding areas with different human densities, the highest prevalence was noted in the villages (34.8% gltA and 31.8% rpoB), followed by cities (14.8% gltA and 11.1% rpoB) and wild areas (7.4% gltA and 14.8% rpoB). The BLAST analysis showed a high similitude (>96%) with four uncharacterized Bartonella genotypes and with two species with zoonotic potential: B. mastomydisand B. tribocorum. The phylogenetic analysis showed a close relationship withB. elizabethae and B. tribocorum. This is the first study to provide evidence of the presence of Bartonella in fleas of R. rattus in Chile, indicating that the villages and arid zone correspond to areas with higher infection risk.Fil: Moreno Salas, Lucila. Universidad de Concepción. Facultad de Ciencias Naturales y Oceanografía. Departamento de Zoología; ChileFil: Espinoza Carniglia, Mario Virgilio. Universidad de Concepción. Facultad de Ciencias Naturales y Oceanografía. Departamento de Zoología; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Lizama Schmeisser, Nicol. Universidad de Concepción. Facultad de Ciencias Naturales y Oceanografía. Departamento de Zoología; ChileFil: Torres, L. Gonzalo. Universidad de Concepción. Facultad de Ciencias Naturales y Oceanografía. Departamento de Zoología; Chile. Universidad Austral de Chile; ChileFil: Silva de la Fuente, María Carolina. Universidad de Concepción; Chile. Universidad San Sebastian.; ChileFil: Lareschi, Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: González Acuña, Daniel. Universidad de Concepción; Chil

    Re-evaluation of the Fijianolide/Laulimalide Chemotype Suggests an Alternate Mechanism of Action for C-15/C-20 Analogs.

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    Herein, we report on naturally derived microtubule stabilizers with activity against triple negative breast cancer (TNBC) cell lines, including paclitaxel, fijianolide B/laulimalide (3), fijianolide B di-acetate (4), and two new semisynthetic analogs of 3, which include fijianolide J (5) and fijianolide L (6). Similar to paclitaxel, compound 3 demonstrated classic microtubule stabilizing activity with potent (GI50 = 0.7–17 nM) antiproliferative efficacy among the five molecularly distinct TNBC cell lines. Alternatively, compounds 5 or 6, generated from oxidation of C-20 or C-15 and C-20 respectively, resulted in a unique profile with reduced potency (GI50 = 4–9 μM), but improved efficacy in some lines, suggesting a distinct mechanism of action. The C-15, C-20 di-acetate, and dioxo modifications on 4 and 6 resulted in compounds devoid of classic microtubule stabilizing activity in biochemical assays. While 4 also had no detectable effect on cellular microtubules, 6 promoted a reorganization of the cytoskeleton resulting in an accumulation of microtubules at the cell periphery. Compound 5, with a single C-20 oxo substitution, displayed a mixed phenotype, sharing properties of 3 and 6. These results demonstrate the importance of the C-15/C-20 chiral centers, which appear to be required for the potent microtubule stabilizing activity of this chemotype and that oxidation of these sites promotes unanticipated cytoskeletal alterations that are distinct from classic microtubule stabilization, likely through a distinct mechanism of action
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