Mueller Matrix Measurement of Electrospun Fiber Scaffolds for Tissue Engineering

Electrospun fiber scaffolds are gaining in importance in the area of tissue engineering. They can be used, for example, to fabricate graded implants to mimic the tendon bone junction. For the grading of the tensile strength of the fiber scaffolds, the orientation of the fibers plays a major role. This is currently measured by hand in scanning electron microscope (SEM) images. In this work, a correlation between polarimetric information generated by measuring the Mueller matrix (MM) and the orientation of the fibers of electrospun fiber scaffolds is reported. For this, the MM of fiber scaffolds, which were manufactured with different production parameters, was measured and analyzed. These data were correlated with fiber orientation and mechanical properties, which were evaluated in an established manner. We found that by measurement of the MM the production parameters as well as the relative orientation of the fibers in space can be determined. Thus, the MM measurement is suitable as an alternative tool for non-contact, non-destructive determination of the production parameters and, thus, the degree of alignment of electrospun fiber scaffolds

Blending chitosan-g-poly(caprolactone) with poly(caprolactone) by electrospinning to produce functional fiber mats for tissue engineering applications

Use of electrospun fiber mats for tissue engineering applications has become increasingly prominent. One of the most important polymers in research, poly(ε-caprolactone) (PCL), however, lacks biological performance, easy access to modifications and cellular recognition sites. To improve these properties and to enable further modifications, PCL was blended with chitosan grafted with PCL (CS-g-PCL) and subsequently processed via electrospinning. In this way, chitosan was enriched at the fiber's surface presenting cationic amino groups. The fiber mats were analyzed by various techniques such as scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and X-ray photoelectron spectroscopy (XPS). Furthermore, analyzing thermal properties and crystallinity, showed that an increased content of CS-g-PCL in blend composition leads to a higher overall crystallinity in produced fiber mats. Blending CS-g-PCL into PCL significantly increased initial cellular attachment and proliferation as well as cell vitality, while maintaining adequate mechanical properties, fiber diameter, and interstitial volume. As proof of principle for easy access to further modification, fluorescently labeled alginate (Alg-FA) was attached to the fiber's surface and verified by CLSM. Hence, blending CS-g-PCL with PCL can overcome an inherent weakness of PCL and create bioactive implants for tissue engineering applications. © 2019 The Authors. Journal of Applied Polymer Science published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48650. © 2019 The Authors. Journal of Applied Polymer Science published by Wiley Periodicals, Inc

Modeling the hydromechanical solution for maintaining fish migration continuity at coastal structures

To promote water control in coastal areas developed for agriculture, tidal hydraulic structures (doors and flap gates) are used for the hydraulic management of irrigation and drainage networks. By closing when the water level increases due to the tide, they prevent sea water inflow. However, fish using the tidal wave to move forward (e.g., glass eels) are also blocked from accessing the hydrologic network. There are hydromechanical solutions to mitigate these problems, such as adding a wooden block to leave an opening at high tide or adding a spring to delay the closing of the structure. The latter solution allows the structure to remain open only during a part of high tide. Designed empirically, these solutions can either alter the hydraulic control performance or be insufficiently effective for fish passage. This study proposes an operating model approach for hydromechanical structures that takes these passage solutions into account. This approach makes it possible to evaluate the performance of the passage solutions for fish passage and hydraulic regulation. With the help of these models, it is possible to design solutions that ensure a compromise between the passability of fish species and agricultural uses

Skewing effect of sulprostone on dendritic cell maturation compared with dinoprostone.

Abstract Background Dendritic cells (DCs) are the most efficient antigen-presenting cells and act at the center of the immune system owing to their ability to control both immune tolerance and immunity. In cancer immunotherapy, DCs play a key role in the regulation of the immune response against tumors and can be generated ex vivo with different cytokine cocktails. Methods . We evaluated the feasibility of dinoprostone (PGE 2 ) replacement with the molecular analog sulprostone, in our good manufacturing practice (GMP) protocol for the generation of DC-based cancer vaccine. We characterized the phenotype and the function of DCs matured in the presence of sulprostone as a potential substitute of dinoprostone in the pro-inflammatory maturation cocktail consisting of tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β) and IL-6. Results . We found that sulprostone invariably reduces the recovery, but does not significantly modify the viability and the purity of DCs. The presence of sulprostone in the maturation cocktail increases the adhesion of single cells and of clusters of DCs to the flask, making them more similar to their immature counterpart in terms of adhesion and spreading proprieties. Moreover, we observed that sulprostone impairs the expression of co-stimulatory molecules and the spontaneous as well as the directed migration capacity of DCs. Discussion These findings underscore that the synthetic analog sulprostone strongly reduces the functional quality of DCs, thus cannot replace dinoprostone in the maturation cocktail of monocyte-derived DCs

Analysis of the denitrification pathway and greenhouse gases emissions in Bradyrhizobium sp. strains used as biofertilizers in South America

Aims Greenhouse gases are considered potential atmospheric pollutants, with agriculture being one of the main emission sources. The practice of inoculating soybean seeds with Bradyrhizobium sp. might contribute to nitrous oxide (N2O) emissions. We analyzed this capacity in five of the most used strains of Bradyrhizobium sp. in South America. Methods and Results We analyzed the denitrification pathway and N2O production by B. japonicum E109 and CPAC15, B. diazoefficiens CPAC7, and B. elkanii SEMIA 587 and SEMIA 5019, both in free‐living conditions and symbiosis with soybean. The in silico analysis indicated the absence of nosZ genes in B. japonicum and the presence of all denitrification genes in B. diazoefficiens strains, as well as the absence of nirK, norC and nosZ genes in B. elkanii. The in planta analysis confirmed the N2O production under saprophytic conditions or symbiosis with soybean roots nodules. In the last case up to 26·1 and 18·4 times higher in plants inoculated with SEMIA5019 and E109 respectively, than in those inoculated with USDA110. Conclusions The strains E109, SEMIA 5019, CPAC15 and SEMIA 587 showed the highest N2O production both as free‐living cells and in symbiotic conditions in comparison with USDA110 and CPAC7, which do have the nosZ gene. Although norC and nosZ could not be identified in silico or in vitro in SEMIA 587 and SEMIA 5019, these strains showed capacity to produce N2O in our experimental conditions. Significance and Impact of Study This is the first report to analyze and confirm the incomplete denitrification capacity and N2O production in four of the five most used strains of Bradyrhizobium sp. for soybean inoculation in South America.Fil: Obando Castellanos, Dolly Melissa. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Ciencias Naturales. Laboratorio de Fisiología Vegetal y de la Interacción Planta-microorganismo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Correa-Galeote, David. Consejo Superior de Investigaciones Científicas. Estación Experimental del Zaidín; EspañaFil: Castellano-Hinojosa, Antonio. Consejo Superior de Investigaciones Científicas. Estación Experimental del Zaidín; EspañaFil: Gualpa, José Luis. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Ciencias Naturales. Laboratorio de Fisiología Vegetal y de la Interacción Planta-microorganismo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Hidalgo, Alba. Consejo Superior de Investigaciones Científicas. Estación Experimental del Zaidín; EspañaFil: de Dios Alché, Juan. Consejo Superior de Investigaciones Científicas. Estación Experimental del Zaidín; EspañaFil: Bedmar, Eulogio. Consejo Superior de Investigaciones Científicas. Estación Experimental del Zaidín; EspañaFil: Cassan, Fabricio Dario. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquimicas y Naturales. Instituto de Investigaciones Agrobiotecnologicas. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Cordoba. Instituto de Investigaciones Agrobiotecnologicas.; Argentin

Using microlensed quasars to probe the structure of the Milky Way

This paper presents an investigation into the gravitational microlensing of quasars by stars and stellar remnants in the Milky Way. We present predictions for the all-sky microlensing optical depth, time-scale distributions and event rates for future large-area sky surveys. As expected, the total event rate increases rapidly with increasing magnitude limit, reflecting the fact that the number density of quasars is a steep function of magnitude. Surveys such as Pan-STARRS and LSST should be able to detect more than ten events per year, with typical event durations of around one month. Since microlensing of quasar sources suffers from fewer degeneracies than lensing of Milky Way sources, they could be used as a powerful tool for recovering the mass of the lensing object in a robust, often model-independent, manner. As a consequence, for a subset of these events it will be possible to directly `weigh' the star (or stellar remnant) that is causing the lensing signal, either through higher order microlensing effects and/or high-precision astrometric observations of the lens star (using, for example, Gaia or SIM-lite). This means that such events could play a crucial role in stellar astronomy. Given the current operational timelines for Pan-STARRS and LSST, by the end of the decade they could potentially detect up to 100 events. Although this is still too few events to place detailed constraints on Galactic models, consistency checks can be carried out and such samples could lead to exciting and unexpected discoveries.Comment: 11 pages, 8 figures. MNRAS (in press). Minor revisions according to referee's report; mainly presentational issues and clarification of a few items in the discussion; results and conclusions remain unchange

Disrupting Primordial Planet Signatures: The Close Encounter of Two Single-Planet Exosystems in the Galactic Disc

During their main sequence lifetimes, the majority of all Galactic Disc field stars must endure at least one stellar intruder passing within a few hundred AU. Mounting observations of planet-star separations near or beyond this distance suggest that these close encounters may fundamentally shape currently-observed orbital architectures and hence obscure primordial orbital features. We consider the commonly-occurring fast close encounters of two single-planet systems in the Galactic Disc, and investigate the resulting change in the planetary eccentricity and semimajor axis. We derive explicit 4-body analytical limits for these variations and present numerical cross-sections which can be applied to localized regions of the Galaxy. We find that each wide-orbit planet has a few percent chance of escape and an eccentricity that will typically change by at least 0.1 due to these encounters. The orbital properties established at formation of millions of tight-orbit Milky Way exoplanets are likely to be disrupted.Comment: 23 pages, 23 figures, 1 table, 1 appendix, accepted for publication in MNRA

Hydraulic management of coastal freshwater marsh to conciliate local water needs and fish passage

Water control structures, used to regulate water levels and flow exchange in coastal marshes, act as barriers during fish migration between the ocean and brackish or freshwater ecosystems. Usual fish pass solutions may be unsuitable for obstacles subject to significant water level variations such as tidal range. This study proposes new solutions that were developed, implemented and evaluated on a marsh controlled by a series of hydraulic structures. These solutions were based on soft physical modifications (passive management) of the control gates, and on adaptations of their operation rules (active management). To evaluate the impacts of these adaptations, a hydraulic model of the marsh was built. It solves the one-dimensional Saint-Venant equations and appropriate gate equations. The model was used to identify management rules of control structures in a way to improve fish migration without significantly affecting the initial hydraulic management of the marsh (i.e. targeted seasonal water levels). Fish passability of upstream structures could be improved by managing downstream ones. It was concluded that the combination of active and passive management of water control structures could largely increase the passability of these obstacles during glass eel migration, while limiting seawater intrusion in the marsh and maintaining water levels into a range compatible with marsh management needs

Assessment of Trace Metals in Sediments from Khnifiss Lagoon (Tarfaya, Morocco)

Surface sediments from Khnifiss lagoon (Morocco) were analyzed to evaluate the contamination degree of the area. Concentrations of V, Cr, Co, Ni, Cu, Zn, As, Cd, Hg, and Pb were determined on samples taken during the summer and the autumn of 2016. On the whole, higher concentrations were found in the summer season. The results revealed the following average concentrations (mg/kg), reported in descending order: Zn (51.7 ± 31.3) > V (38.8 ± 24.7) > Cr (26.6 ± 17.8) > Ni (16.5 ± 5.47) > As (8.50 ± 2.00) > Cu (6.60 ± 3.81) > Pb (6.13 ± 3.46) > Co (3.57 ± 2.09) > Cd (0.16 ± 0.11) > Hg (0.006 ± 0.001). Organic matter showed a positive significant correlation with some trace metals (mainly V, Cr, Co, Zn, Cd, Pb). Three pollution indices were calculated: Enrichment Factor (EF), Index of Geo−accumulation (Igeo), and Pollution Load Index (PLI). Minimal enrichments (for Zn, As, and Cd) were detected at some sampling points. Overall indices showed that the Khnifiss sediments can be classified as not contaminated, and that the trace metals amounts found are ascribable to the geogenic origin. The results of this work can be used as a starting point for further evaluations of trace metals distribution in Moroccan lagoons