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Mathematical models have been remarkable tools for knowing in advance the appropriate time to enforce population restrictions and distribute hospital resources. Here, we present a mathematical Susceptible-Exposed-Infectious-Recovered (SEIR) model to study the transmission dynamics of COVID-19 in Granada, Spain, taking into account the uncertainty of the phenomenon. In the model, the patients moving throughout the hospital’s departments (intra-hospitalary circuit) are considered in order to help to optimize the use of a hospital’s resources in the future. Two main seasons, September–April (autumn-winter) and May–August (summer), where the hospital pressure is significantly different, have been included. The model is calibrated and validated with data obtained from the hospitals in Granada. Possible future scenarios have been simulated. The model is able to capture the history of the pandemic in Granada. It provides predictions about the intra-hospitalary COVID-19 circuit over time and shows that the number of infected is expected to decline continuously from May without an increase next autumn–winter if population measures continue to be satisfied. The model strongly suggests that the number of infected cases will reduce rapidly with aggressive vaccination policies. The proposed study is being used in Granada to design public health policies and perform wise re-distribution of hospital resources in advance., Spanish Ministerio de Economía, Industria y Competitividad (MINECO), Agencia Estatal de Investigación (AEI), Fondo Europeo de Desarrollo Regional (FEDER UE) grant MTM2017-89664-P, European Union through the Operational Program of the [European Regional Development Fund (ERDF)/European Social Fund (ESF)] of the Valencian Community 2014–2020, Ramón Areces Foundation, Madrid, Spain (CIVP18A3920).

Immunotherapy has the potential to change the way all cancer types are treated and cured. Cancer immunotherapies use elements of the patient immune system to attack tumor cells. One of the most successful types of immunotherapy is CAR-T cells. This treatment works by extracting patient's T-cells and adding to them an antigen receptor allowing tumor cells to be recognized and targeted. These new cells are called CAR-T cells and are re-infused back into the patient after expansion in-vitro. This approach has been successfully used to treat B-cell malignancies (B-cell leukemias and lymphomas). However, its application to the treatment of T-cell leukemias faces several problems. One of these is fratricide, since the CAR-T cells target both tumor and other CAR-T cells. This leads to nonlinear dynamical phenomena amenable to mathematical modeling. In this paper we construct a mathematical model describing the competition of CAR-T, tumor and normal T-cells and studied some basic properties of the model and its practical implications. Specifically, we found that the model reproduced the observed difficulties for in-vitro expansion of the therapeutic cells found in the laboratory. The mathematical model predicted that CAR-T cell expansion in the patient would be possible due to the initial presence of a large number of targets. We also show that, in the context of our mathematical approach, CAR-T cells could control tumor growth but not eradicate the disease.(c) 2020 Elsevier B.V. All rights reserved.

BACKGROUND: Antiangiogenic therapies for glioblastoma (GBM) such as bevacizumab (BVZ), have been unable to extend survival in large patient cohorts. However, a subset of patients having angiogenesis-dependent tumors might benefit from these therapies. Currently, there are no biomarkers allowing to discriminate responders from non-responders before the start of the therapy. METHODS: 40 patients from the randomized GENOM009 study complied the inclusion criteria (quality of images, clinical data available). Of those, 23 patients received first line temozolomide (TMZ) for eight weeks and then concomitant radiotherapy and TMZ. 17 patients received BVZ+TMZ for seven weeks and then added radiotherapy to the treatment. Clinical variables were collected, tumors segmented and several geometrical measures computed including: Contrast enhancing (CE), necrotic, and total volumes; equivalent spherical CE width; several geometric measures of the CE 'rim' geometry and a set of image texture measures. The significance of the results was studied using Kaplan-Meier and Cox proportional hazards analysis. Correlations were assessed using Spearman correlation coefficients. RESULTS: Kaplan-Meier and Cox proportional hazards analysis showed that total, CE and inner volume (p = 0.019, HR = 4.258) and geometric heterogeneity of the CE areas (p = 0.011, HR = 3.931) were significant parameters identifying response to BVZ. The group of patients with either regular CE areas (small geometric heterogeneity, median difference survival 15.88 months, p = 0.011) or those with small necrotic volume (median survival difference 14.50 months, p = 0.047) benefited substantially from BVZ. CONCLUSION: Imaging biomarkers related to the irregularity of contrast enhancing areas and the necrotic volume were able to discriminate GBM patients with a substantial survival benefit from BVZ. A prospective study is needed to validate our results. This work has been supported by Ministerio de Economía y Competitividad/FEDER, Spain [grant number MTM2015-71200-R], Consejería de Educación Cultura y Deporte from Junta de Comunidades de Castilla-La Mancha, Spain [grant number PEII-2014-031-P] and James S. Mc. Donnell Foundation 21st Century Science Initiative in Mathematical and Complex Systems Approaches for Brain Cancer [Special Initiative Collaborative – Planning Grant 220020420 and Collaborative award 220020450]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Objective: The main objective of this retrospective work was the study of three-dimensional (3D) heterogeneity measures of post-contrast pre-operative MR images acquired with T1 weighted sequences of patients with glioblastoma (GBM) as predictors of clinical outcome. Methods: 79 patients from 3 hospitals were included in the study. 16 3D textural heterogeneity measures were computed including run-length matrix (RLM) features (regional heterogeneity) and co-occurrence matrix (CM) features (local heterogeneity). The significance of the results was studied using Kaplan?Meier curves and Cox proportional hazards analysis. Correlation between the variables of the study was assessed using the Spearman?s correlation coefficient. Results: Kaplan?Meyer survival analysis showed that 4 of the 11 RLM features and 4 of the 5 CM features considered were robust predictors of survival. The median survival differences in the most significant cases were of over 6 months. Conclusion: Heterogeneity measures computed on the post-contrast pre-operative T1 weighted MR images of patients with GBM are predictors of survival. Advances in knowledge: Texture analysis to assess tumour heterogeneity has been widely studied. However, most works develop a two-dimensional analysis, focusing only on one MRI slice to state tumour heterogeneity. The study of fully 3D heterogeneity textural features as predictors of clinical outcome is more robust and is not dependent on the selected slice of the tumour.

International audience; The present work deals with hierarchical composites in three dimensions, whose constituents behave as non-aging linear viscoelastic materials. We model the influence that imperfect viscoelastic interfaces have on the macroscopic effective response of these structures. As an initial approach, the problem of two bodies in adhesion is studied and in particular the case of soft viscoelastic interface at zero-order is considered. We deduce the integral form of the viscoelastic interface by applying the matched asymptotic expansion method, the correspondence principle, and the Laplace–Carson transform. Then, by adapting the integral form previously obtained, we address a heterogeneous problem for periodic structures. Here, theoretical results obtained for perfect interfaces are extended to the formal viscoelastic counterpart of the spring-type imperfect interface model. Finally, we show the potential of the proposed approach by performing calculations of effective properties in heterogeneous structures with two- and three-scale geometrical configurations and imperfect viscoelastic interfaces.

Effective properties of non-aging linear viscoelastic and hierarchical composites are investigated via a three-scale asymptotic homogenization method. In this approach, we consider the assumption of a generalized periodicity in the different structural levels and their characterization through the so-called stratified functions. The expressions for the associated local and homogenized problems, and the effective coefficients are derived at each level of organization by using the correspondence principle and the Laplace-Carson transform. Considering isotropic components and a perfect contact at the interfaces between the constituents, analytical solutions, in the Laplace-Carson space, are found for the local problems and the effective coefficients are computed. An interconversion procedure between the effective relaxation modulus and the effective creep compliance is carried out for obtaining information about both viscoelastic properties. The numerical inversion to the original temporal space is also performed. Finally, we exploit the potential of the approach and study the overall properties of a hierarchical viscoelastic composite structure representing the dermis.

International audience; In this contribution an analysis of static properties of transversely isotropic, porous and nano-composites is considered. Present work features explicit formulas for effective coefficient in these types of composites. The reinforcements of the composites are a set of spheroidal inclusions with identical size and shape. The center is randomly distributed and the inclusions are embedded in an homogeneous infinite medium (matrix). An study of theoretical predictions obtained by Maxwell approach using two different density distribution functions, which describe the alignment inclusions is done. The method allows to report the static effective elastic coefficients in composites ensemble with inclusions of different geometrical shapes and configurations embedded into a matrix. The effective properties of composites are computed using the Maxwell homogenization method in Matlab software. Another novelty of this contribution is the calculation of new explicit analytical formulas for the control of the alignment tensors N* and Ns∗ which is in charged of the alignment distribution of inclusions within matrix through disorder parameters λ and s, respectively. The alignment tensors N∗ and Ns∗ are obtained as average of all possible alignments of the inclusions inside the composite. Numerical results are obtained and compared with some other theoretical approaches reported in the literature.

International audience; In most composites, the fiber–matrix adhesion is imperfect; the continuity conditions for stresses and displacements are not satisfied. In this contribution, effective elastic moduli are obtained by means of the asymptotic homogenization method (AHM), for three-phase fibrous composites (matrix/mesophase/fiber) with parallelogram periodic cell. Interaction between fiber and matrix is considered, and this is called the mesophase model where the nonuniform mesophase is studied. Besides, there is another type of matrix–fiber contact which is called nonuniform spring imperfect contact. In this case, the contrast or jump of the displacements in the boundary of each phase is proportional to the corresponding component of the tension in the interface in terms of a parameter given by a certain function that depends on the position. The constituents of the composites exhibit transversely isotropic properties. A doubly periodic parallelogram array of cylindrical inclusions under longitudinal shear is considered. The three-phase model is validated by the Finite Element Method and the AHM both approaches applied to two-phase composites with nonuniform spring imperfect contact. Comparisons with theoretical and experimental results verified that the present model is efficient for the analysis of composites with presence of nonuniform imperfect interface and parallelogram cell. The effect of the nonuniform imperfection on the shear effective property is observed. The present method can provide benchmark results for other numerical and approximate methods.

International audience; The present work deals with the estimation of the linear viscoelastic effective properties for composites with periodic structure and rectangular cross-section fibers, using the two-scale asymptotic homogenization method (AHM). As a particular case, the effective properties for a layered medium with transversely isotropic properties are obtained. Two times the homogenization method, in different directions, according to the geometrical configuration of the composite material is applied for deriving the analytical expressions of the viscoelastic effective properties for a composite material with rectangular cross-section fibers, periodically distributed along one axis. In addition to that, models with different creep kernels, in particular, the Rabotnov’s kernel are analyzed. Finally, the numerical computation of the effective viscoelastic properties is developed for the analysis of the results. Moreover, a numerical algorithm using FEM is developed in the present work. Comparisons with other approaches are given as a validation of the present model.

International audience; Boolean networks are important models of biochemical systems, located at the high end of the abstraction spectrum. A number of Boolean gene networks have been inferred following essentially the same method. Such a method first considers experimental data for a typically underdetermined "regulation" graph. Next, Boolean networks are inferred by using biological constraints to narrow the search space, such as a desired set of (fixed-point or cyclic) attractors. We describe Griffin, a computer tool enhancing this method. Griffin incorporates a number of well-established algorithms, such as Dubrova and Teslenko's algorithm for finding attractors in synchronous Boolean networks. In addition, a formal definition of regulation allows Griffin to employ "symbolic" techniques, able to represent both large sets of network states and Boolean constraints. We observe that when the set of attractors is required to be an exact set, prohibiting additional attractors, a naive Boolean coding of this constraint may be unfeasible. Such cases may be intractable even with symbolic methods, as the number of Boolean constraints may be astronomically large. To overcome this problem, we employ an Artificial Intelligence technique known as "clause learning" considerably increasing Griffin's scalability. Without clause learning only toy examples prohibiting additional attractors are solvable: only one out of seven queries reported here is answered. With clause learning, by contrast, all seven queries are answered. We illustrate Griffin with three case studies drawn from the Arabidopsis thaliana literature. Griffin is available at: http://turing.iimas.unam.mx/griffin.

ISI Document Delivery No.: FD4KCTimes Cited: 0Cited Reference Count: 45Crespo, Maria Ivorra, Benjamin Ramos, Angel ManuelSpanish "Ministry of Economy and Competitiveness" [MTM2011-22658, MTM2015-64865-P]; research group MOMAT - Banco Santander [910480]; Universidad Complutense de Madrid; Junta de Andalucia; European Regional Development Fund [P12-TIC301]; French Labex Numev [ANR-10-LABX-20]This work was carried out thanks to the financial support of the Spanish "Ministry of Economy and Competitiveness" under projects MTM2011-22658 and MTM2015-64865-P; the research group MOMAT (Ref. 910480) supported by "Banco Santander" and "Universidad Complutense de Madrid"; and the "Junta de Andalucia" and the European Regional Development Fund through project P12-TIC301. The authors thank the French Labex Numev (convention ANR-10-LABX-20) for the postdoctoral grant of the first author at UMR MISTEA, Montpellier, France.0Texas state univSan marcos; In this work, we present an asymptotic analysis of a coupled system of two advection-diffusion-reaction equations with Danckwerts boundary conditions, which models the interaction between a microbial population (e.g., bacteria), called biomass, and a diluted organic contaminant (e.g., nitrates), called substrate, in a continuous flow bioreactor. This system exhibits, under suitable conditions, two stable equilibrium states: one steady state in which the biomass becomes extinct and no reaction is produced, called washout, and another steady state, which corresponds to the partial elimination of the substrate. We use the linearization method to give sufficient conditions for the linear asymptotic stability of the two stable equilibrium configurations. Finally, we compare our asymptotic analysis with the usual asymptotic analysis associated to the continuous bioreactor when it is modeled with ordinary differential equations.

WOS: 000398405000001, The conduction band and electron-donor impurity states in elliptic-shaped GaAs quantum dots under the effect of an externally applied electric field are calculated within the effective mass and adiabatic approximations using two different numerical approaches: a spectral scheme and the finite element method. The resulting energies and wave functions become the basic information needed to evaluate the interstate optical absorption in the system, which is reported as a function of the geometry, the electric field strength, and the temperature., Vietnam National Foundation for Science and Technology Development (NAFOSTED) [103.01-2015.93]; Migracion Sismica Pre-Apilado en Profundidad por Extrapolacion de Campos de Onda Utilizando Computacion de Alto Desempeno para Datos Masivos en Zonas Complejas [111553130555], This research is funded by Vietnam National Foundation for Science and Technology Development (NAFOSTED) under Grant no. 103.01-2015.93. The authors are grateful to the Colombian Agencies CODI-Universidad de Antioquia (Estrategia de Sostenibilidad de la Universidad de Antioquia) and Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (C.A. Duque and A.L. Morales Exclusive Dedication Projects 2016-2017). M.A. Londono is grateful to Colciencias-Ecopetrol for financial support through the project Migracion Sismica Pre-Apilado en Profundidad por Extrapolacion de Campos de Onda Utilizando Computacion de Alto Desempeno para Datos Masivos en Zonas Complejas (Code 111553130555).

International audience; In 1872, G. Darboux defined a family of curves on surfaces of $\mathbb{R}^3$ which are preserved by the action of the Mobius group and share many properties with geodesics. Here, we characterize these curves under the view point of Lorentz geometry and prove that they are geodesics in a 3-dimensional sub-variety of a quadric $\Lambda^4$ contained in the 5-dimensional Lorentz space $\mathbb{R}^5_1$ naturally associated to the surface. We construct a new conformal object: the Darboux plane-field $\mathcal{D}$ and give a condition depending on the conformal principal curvatures of the surface which guarantees its integrability. We show that $\mathcal{D}$ is integrable when the surface is a special canal.

International audience; In 1872, Gaston Darboux defined a family of curves on surfaces in the 3-dimensional Euclidean space $E^3$ which are preserved by the action of the Möbius group and share many properties with geodesics. Here, we study the Darboux curves from a dynamical viewpoint on special canal surfaces, quadrics and some Darboux cyclides. We also describe the generic behavior of Darboux curves near ridge points (zig-zag and beak-to-beak).

International audience; The aim of the present work is to study the influence of the mechanical and electrical imperfections in reinforced piezoelectric composite materials with unidirectional cylindrical fibers periodically distributed in rhombic cells under mechanical and electrical imperfect contacts. The behavior of the composites is studied through two approaches: the two-scale asymptotic homogenization method and the finite element method. The asymptotic homogenization method is applied to a two-phase composite with mechanical and electrical imperfect contacts and to a three-phase composite with perfect contact in the interphase. The constituents of the composite are homogeneous piezoelectric materials with transversely isotropic properties. The local problems are formulated for the spring-capacitor and three-phase models by the asymptotic homogenization method. The solution of each plane local problem is found using potential methods of a complex variable and the properties of doubly periodic Weierstrass elliptic functions. Closed-form formulae are obtained for the effective properties of the composites with both types of imperfect contacts and different configuration of the cells. The finite element method is implemented for analysis of piezoelectric composite materials with unidirec-tional cylindrical fibers periodically distributed in rhombic cells under mechanical and electrical imperfect contacts. Some numerical examples are given under the presence of both imperfect contacts and different arrangement of the cells. Comparisons between the numerical results reported by asymptotic homogenization method and finite element method are provided.

International audience; For a large class of composites, the adhesion at the fiber–matrix interface is imperfect i.e. the continuity conditions for displacements and often for stresses is not satisfied. In the present contribution, effective elastic moduli for this kind of composites are obtained by means of the Asymptotic Homogenization Method (AHM). Interaction between fiber and matrix is considered for linear elastic fibrous composites with parallelogram periodic cell. In this case, the contrast or jump in the displacements on the boundary of each phase is proportional to the corresponding component of the tension on the interface. A general anisotropic behavior of the interphase is assumed and the interface stiffnesses are explicitly given in terms of the elastic constants of the interphase. The constituents of the composites exhibit transversely isotropic properties. A doubly periodic parallelogram array of cylindrical inclusions is considered. Comparisons with theoretical and experimental results verified that the present model is efficient for the analysis of composites with presence of imperfect interface and parallelogram cell. The present method can provide benchmark results for other numerical and approximate methods.

12th International Conference on Optics of Surfaces and Interfaces (OSI) -- JUN 25-30, 2017 -- Trin Coll Dublin, Sch Phys, Dublin, IRELAND, WOS: 000430113000017, The electron states in a holey elliptically shaped GaAs quantum dot are investigated within the effective mass scheme with the use of the adiabatic approximation and the finite element method. The effects of a donor impurity center and an applied electric field are particularly taken into account. Electron-impurity energies are reported as functions of both the geometry of the quantum dot and the applied field intensity, whereas temperature effects are also included. The analysis of electron-impurity intersubband transitions allows the investigation of the light absorption response of the system., CODI-Universidad de Antioquia (Estrategia de Sostenibilidad de la Universidad de Antioquia); CODI-Universidad de Antioquia (research project "Manipulacion de propiedades optoelectronicas de nanoestructuras semiconductoras por ondas acusticas superficiales"); Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia; Universidad EIA; Universidad de Antioquia through the EIA-UdeA-UdeM-project "Desarrollo de fotodetectores en el infrarrojo usando pozos cuanticos ajustables con dopamiento delta dentro del pozo"; Colombian Oil Company ECOPETROL; Colombian Oil Company COLCIENCIAS [0266-2013], This research was partially supported by Colombian Agencies: CODI-Universidad de Antioquia (Estrategia de Sostenibilidad de la Universidad de Antioquia and research project "Manipulacion de propiedades optoelectronicas de nanoestructuras semiconductoras por ondas acusticas superficiales") and Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD and ALM exclusive dedication projects 2017-2018). RLR and CAD are grateful to Universidad EIA and Universidad de Antioquia for financial support through the EIA-UdeA-UdeM-project "Desarrollo de fotodetectores en el infrarrojo usando pozos cuanticos ajustables con dopamiento delta dentro del pozo." This work is supported by Colombian Oil Company ECOPETROL and COLCIENCIAS as a part of the research project grant No. 0266-2013.

International audience; In the present work, applying the asymptotic homogenization method (AHM), the derivation of the antiplane effective properties for three-phase magneto-electro-elastic fiber unidirectional reinforced composite with parallelogram cell symmetry is reported. Closed analytical expressions for the antiplane local problems on the periodic cell and the corresponding effective coefficients are provided. Matrix and inclusions materials belong to symmetry class 6mm. Numerical results are reported and compared with the eigenfunction expansion-variational method (EEVM) and other theoretical models. Good agreements are found for these comparisons. In addition, with the herein implemented solution, it is possible to reproduce the effective properties of the reduced cases such as piezoelectric or elastic composites obtain- ing good agreements with previous reports.

In this contribution, effective elastic moduli are obtained by means of the asymptotic homogenization method, for oblique two-phase fibrous periodic composites with non-uniform imperfect contact conditions at the interface. This work is an extension of previous reported results, where only the perfect contact for elastic or piezoelectric composites under imperfect spring model was considered. The constituents of the composites exhibit transversely isotropic properties. A doubly periodic parallelogram array of cylindrical inclusions under longitudinal shear is considered. The behavior of the shear elastic coefficient for different geometry arrays related to the angle of the cell is studied. As validation of the present method, some numerical examples and comparisons with theoretical results verified that the present model is efficient for the analysis of composites with presence of imperfect interface and parallelogram cell. The effect of the non uniform imperfection on the shear effective property is observed. The present method can provide benchmark results for other numerical and approximate methods. © 2013 Elsevier Ltd. All rights reserved.

International audience; In this work, two-phase parallel fiber-reinforced periodic piezoelectric composites are considered wherein the constituents exhibit transverse isotropy and the cells have different configurations. Mechanical imperfect contact at the interface of the composites is studied via linear spring model. The statement of the problem for two phase piezoelectric composites with mechanical imperfect contact is given. The local problems are formulated by means of the asymptotic homogenization method (AHM) and their solutions are found using complex variable theory. Analytical formulae are obtained for the effective properties of the composites with spring imperfect type of contact and different parallelogram cells. Some numerical examples and comparisons with other theoretical results illustrate that the model is efficient for the analysis of composites with presence of parallelogram cells and the aforementioned imperfect contact.