On the Volterra property of a boundary problem with integral gluing condition for mixed parabolic-hyperbolic equation

In the present work we consider a boundary value problem with gluing conditions of integral form for parabolic-hyperbolic type equation. We prove that the considered problem has the Volterra property. The main tools used in the work are related to the method of the integral equations and functional analysis.Comment: 18 page

On the Existence of Eigenvalues of a Boundary Value Problem with Transmitting Condition of the Integral Form for a Parabolic-Hyperbolic Equation

In the paper, we investigate a local boundary value problem with transmitting condition of the integral form for mixed parabolic-hyperbolic equation with non-characteristic line of type changing. Theorem on strong solvability of the considered problem has been proved and integral representation of the solution is obtained in a functional space. Using Lidskii Theorem on coincidences of matrix and spectral traces of nuclear operator and Gaal’s formula for evaluating traces of nuclear operator, which is represented as a product of two Hilbert-Schmidt operators, we prove the existence of eigenvalues of the considered problemThe research of the first author is supported by the grant of the Committee of Sciences, Ministry of Education and Science of the Republic of Kazakhstan to the Institute of Information and Computational Technologies, project AP05131026. Second author is supported by the Agencia Estatal de Investigación (AEI) of Spain under grant MTM2016-75140-P, co-financed by the European Community fund FEDER and by Xunta de Galicia, project ED431C 2019/02 (Spain)S

Esterase Cleavable 2D Assemblies of Magnetic Iron Oxide Nanocubes: Exploiting Enzymatic Polymer Disassembling to Improve Magnetic Hyperthermia Heat Losses

Here, we report a nanoplatform based on iron oxide nanocubes (IONCs) coated with a bioresorbable polymer that, upon exposure to lytic enzymes can be disassembled increasing the heat performances in comparison with the initial clusters. We have developed bi-dimensional (2D) clusters by exploiting benchmark iron oxide nanocubes as heat mediators for magnetic hyperthermia and a polyhydroxyalkanoate (PHA) copolymer, a biodegradable polymer produced by bacteria that can be digested by intracellular esterase enzymes. The comparison of magnetic heat performance of the 2D assemblies with 3D centro-symmetrical assemblies or single iron oxide nanocubes emphasize the benefit of the 2D assembly. On one hand, the heat losses of 2D assemblies dispersed in water are better than the 3D assemblies, but worse than for single nanocubes. On the other hand, when the bi-dimensional magnetic beads (2D-MNBs) are incubated with the esterase enzyme at a physiological temperature, their magnetic heat performances began to progressively increase. After 2 hours of incubation, specific absorption rate values of the 2D assembly double the ones of individually coated nanocubes. Such an increase can be mainly correlated to the splitting of the 2D-MNBs into smaller size clusters with a chain- like configuration containing few nanocubes. Moreover, 2D-MNBs exhibited non-variable-heat performances even after intentionally inducing their aggregation. Magnetophoresis measurements indicate a comparable response of 3D and 2D clusters to external magnets (0.3T) that is by far faster than that of single nanocubes. This feature is crucial for a physical accumulation of magnetic materials in the presence of magnetic field gradients. This system is the first example of a nanoplatform that, upon exposure to lytic enzymes, such as those present in a tumor environment, can be disassembled from the initial 2D-MNB organization to chain-like assemblies with clear improvement of the heat magnetic losses resulting in better heat dissipation performances. The potential application of 2D nano-assemblies based on the cleavable PHAs for preserving their magnetic losses inside cells will benefit hyperthermia therapies mediated by magnetic nanoparticles under alternating magnetic fields

Electrostatic polarization fields trigger glioblastoma stem cell differentiation

Over the last few years it has been understood that the interface between living cells and the underlying materials can be a powerful tool to manipulate cell functions. In this study, we explore the hypothesis that the electrical cell/material interface can regulate the differentiation of cancer stem-like cells (CSCs). Electrospun polymer fibres, either polyamide 66 or poly(lactic acid), with embedded graphene nanoplatelets (GnPs), have been fabricated as CSC scaffolds, providing both the 3D microenvironment and a suitable electrical environment favorable for CSCs adhesion, growth and differentiation. We have investigated the impact of these scaffolds on the morphological, immunostaining and electrophysiological properties of CSCs extracted from human glioblastoma multiform (GBM) tumor cell line. Our data provide evidence in favor of the ability of GnP-incorporating scaffolds to promote CSC differentiation to the glial phenotype. Numerical simulations support the hypothesis that the electrical interface promotes the hyperpolarization of the cell membrane potential, thus triggering the CSC differentiation. We propose that the electrical cell/material interface can regulate endogenous bioelectrical cues, through the membrane potential manipulation, resulting in the differentiation of CSCs. Material-induced differentiation of stem cells and particularly of CSCs, can open new horizons in tissue engineering and new approaches to cancer treatment, especially GBM

Esterase-Cleavable 2D Assemblies of Magnetic Iron Oxide Nanocubes: Exploiting Enzymatic Polymer Disassembling to Improve Magnetic Hyperthermia Heat Losses

Here, we report a nanoplatform based on iron oxide nanocubes (IONCs) coated with a bioresorbable polymer that, upon exposure to lytic enzymes, can be disassembled increasing the heat performances in comparison with the initial clusters. We have developed two-dimensional (2D) clusters by exploiting benchmark IONCs as heat mediators for magnetic hyperthermia and a polyhydroxyalkanoate (PHA) copolymer, a biodegradable polymer produced by bacteria that can be digested by intracellular esterase enzymes. The comparison of magnetic heat performance of the 2D assemblies with 3D centrosymmetrical assemblies or single IONCs emphasizes the benefit of the 2D assembly. Moreover, the heat losses of 2D assemblies dispersed in water are better than the 3D assemblies but worse than for single nanocubes. On the other hand, when the 2D magnetic beads (2D-MNBs) are incubated with the esterase enzyme at a physiological temperature, their magnetic heat performances began to progressively increase. After 2 h of incubation, specific absorption rate values of the 2D assembly double the ones of individually coated nanocubes. Such an increase can be mainly correlated to the splitting of the 2D-MNBs into smaller size clusters with a chain-like configuration containing few nanocubes. Moreover, 2D-MNBs exhibited nonvariable heat performances even after intentionally inducing their aggregation. Magnetophoresis measurements indicate a comparable response of 3D and 2D clusters to external magnets (0.3 T) that is by far faster than that of single nanocubes. This feature is crucial for a physical accumulation of magnetic materials in the presence of magnetic field gradients. This system is the first example of a nanoplatform that, upon exposure to lytic enzymes, such as those present in a tumor environment, can be disassembled from the initial 2D-MNB organization to chain-like assemblies with clear improvement of the heat magnetic losses resulting in better heat dissipation performances. The potential application of 2D nanoassemblies based on the cleavable PHAs for preserving their magnetic losses inside cells will benefit hyperthermia therapies mediated by magnetic nanoparticles under alternating magnetic fields

Biorremediación en suelos contaminados con hidrocarburos

Se estudia la bioremediación de suelos contaminados con el interés de disminuir el efecto contaminante de hidrocarburos a niveles no tóxicos. Los ensayos a escala laboratorio, desarrollados en condiciones de temperatura, aireación y humedad controlada permiten evaluar alternativas de utilización de nutrientes, inoculación de bacterias y/o aprovechamiento de la microflora natural del suelo. Los resultados muestran la activación de la microflora natural por la utilización de nutrientes en proporción adecuada, obteniéndose remociones de hidrocaburo de 70 % en 55 días de proceso. Asimismo, se analiza la efectividad del proceso de bioremediación cuando se utiliza suelo recuperado. Así, la utilización de suelo virgen puede limitarse al mínimo evitando desmontes innecesarios para su provisión.It was studied contaminated soils bioremediation with the interest to decrease the hydrocarbon contaminant effect to no toxic levels. The laboratory assays, developed at temperature, aeration, and moisture controlled conditions let alternative nutrients, commercial microbes addition, and/or natural soil micro flora profit evaluation. The results show the natural micro flora activation because of the adequate proportions nutrients utilization. It was obtained 70 % petroleum hydrocarbon removal in 55 process days. Also, It can limit the native soils utilization and not allowing cutting trees when it is not necessary.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Biorremediación en suelos contaminados con hidrocarburos

Se estudia la bioremediación de suelos contaminados con el interés de disminuir el efecto contaminante de hidrocarburos a niveles no tóxicos. Los ensayos a escala laboratorio, desarrollados en condiciones de temperatura, aireación y humedad controlada permiten evaluar alternativas de utilización de nutrientes, inoculación de bacterias y/o aprovechamiento de la microflora natural del suelo. Los resultados muestran la activación de la microflora natural por la utilización de nutrientes en proporción adecuada, obteniéndose remociones de hidrocaburo de 70 % en 55 días de proceso. Asimismo, se analiza la efectividad del proceso de bioremediación cuando se utiliza suelo recuperado. Así, la utilización de suelo virgen puede limitarse al mínimo evitando desmontes innecesarios para su provisión.It was studied contaminated soils bioremediation with the interest to decrease the hydrocarbon contaminant effect to no toxic levels. The laboratory assays, developed at temperature, aeration, and moisture controlled conditions let alternative nutrients, commercial microbes addition, and/or natural soil micro flora profit evaluation. The results show the natural micro flora activation because of the adequate proportions nutrients utilization. It was obtained 70 % petroleum hydrocarbon removal in 55 process days. Also, It can limit the native soils utilization and not allowing cutting trees when it is not necessary.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Biorremediación en suelos contaminados con hidrocarburos

Se estudia la bioremediación de suelos contaminados con el interés de disminuir el efecto contaminante de hidrocarburos a niveles no tóxicos. Los ensayos a escala laboratorio, desarrollados en condiciones de temperatura, aireación y humedad controlada permiten evaluar alternativas de utilización de nutrientes, inoculación de bacterias y/o aprovechamiento de la microflora natural del suelo. Los resultados muestran la activación de la microflora natural por la utilización de nutrientes en proporción adecuada, obteniéndose remociones de hidrocaburo de 70 % en 55 días de proceso. Asimismo, se analiza la efectividad del proceso de bioremediación cuando se utiliza suelo recuperado. Así, la utilización de suelo virgen puede limitarse al mínimo evitando desmontes innecesarios para su provisión.It was studied contaminated soils bioremediation with the interest to decrease the hydrocarbon contaminant effect to no toxic levels. The laboratory assays, developed at temperature, aeration, and moisture controlled conditions let alternative nutrients, commercial microbes addition, and/or natural soil micro flora profit evaluation. The results show the natural micro flora activation because of the adequate proportions nutrients utilization. It was obtained 70 % petroleum hydrocarbon removal in 55 process days. Also, It can limit the native soils utilization and not allowing cutting trees when it is not necessary.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES