Penta-block copolymer microspheres: Impact of polymer characteristics and process parameters on protein release

Here, we aimed to develop protein loaded microspheres (MSs) using penta-block PLGA-based copolymers to obtain sustained and complete protein release. We varied MS morphology and studied the control of protein release. Lysozyme was used as a model protein and MSs were prepared using the solid-in-oil-in-water emulsion solvent extraction method. We synthesized and studied various penta-block PLGA-based copolymers. Copolymer characteristics (LA/GA ratio and molecular weight of PLGA blocks) influenced MS morphology. MS porosity was influenced by process parameters (such as solvent type, polymer concentration, emulsifying speed), whereas the aqueous volume for extraction and stabilizer did not have a significant effect. MSs of the same size, but different morphologies, exhibited different protein release behavior, with porous structures being essential for the continuous and complete release of encapsulated protein. These findings suggest strategies to engineer the morphology of MSs produced from PLGA-based multi-block copolymers to achieve appropriate release rates for a protein delivery system

Unraveling the complex polymorphic crystallization behavior of the alternating copolymer DMDS-alt-DVE

[Abstract]: A complex crystallization behavior was observe the alternating copolymer DMDS-alt-step-growth polymerization. Understanding the underlying complex crystallization processes of such innovative polythioethers is critical for their application, for example, in polymer coating technologies. These alternating copolymers have polymorphic traits, resulting in different phases that may display distinct crystalline structures. The copolymer DMDS-alt-DVE was studied in an earlier work, where only two crystalline phases were reported: a low melting, L − Tm, and high melting, H − Tm phase. Remarkably, the H − Tm form was only achieved by the previous formation and melting of the L − Tm form. We applied calorimetric techniques encompassing seven orders of magnitude in scanning rates to further explore this complex polymorphic behavior. Most importantly, by rapidly quenching the sample to temperatures well below room temperature, we detected an additional polymorphic form (characterized by a very low melting phase, denoted VL − Tm). Moreover, through tailored thermal protocols, we successfully produced samples containing only one, two, or all three polymorphs, providing insights into their interrelationships. Understanding polymorphism, crystallization, and esulting morphological differences can have significant implications and potential impact on mechanical resistance and barrier roperties.Gobierno Vasco; IT1503-22Gobierno Vasco; IT-1525-22Ministerio de Ciencia e Innovación; PGC2018-094620-A-I00Xunta de Galicia; ED431F 2021/00

The Infrared Behaviour of the Pure Yang-Mills Green Functions

We review the infrared properties of the pure Yang-Mills correlators and discuss recent results concerning the two classes of low-momentum solutions for them reported in literature; i.e. decoupling and scaling solutions. We will mainly focuss on the Landau gauge and pay special attention to the results inferred from the analysis of the Dyson-Schwinger equations of the theory and from "{\it quenched}" lattice QCD. The results obtained from properly interplaying both approaches are strongly emphasized.Comment: Final version to be published in FBS (54 pgs., 11 figs., 4 tabs

Small and large signal stability analysis of IMPSA wind power plant integration on Vietnamese power system

This research presents a study on the small and large signal stability of IMPSA wind power plant with variable speed wind turbines connected to Vietnamese power system. Based on an aggregated wind park model in Power System Analysis Toolbox (PSAT) library, a dynamic model of Ninh Thuan - Binh Thuan grid, a province of Vietnam where a variable speed wind turbine system has been built. The toolboxes such as Power Flow, Time Domain Simulations in PSAT are used to study the small and large signal stability of IMPSA wind power plant and Ninh Thuan - Binh Thuan grid after the occurrence of small and large disturbances, i.e. trip lines and three phase faults, respectively. The different simulation results show how the Vietnamese Wind Power Plant (WPP), equipped with variable speed wind power generators, will respond to disturbances of the buck power system in the near future

Development of anisotropic ferromagnetic composites for low-frequency induction heating technology in medical applications

International audienceModern medical applications such as varicose treatment, hyperthermia, or even endovenous thermal ablation require to bring heat flux locally through the human body. The challenge behind such techniques resides in converting electrical power into heat flux and transfer it directly to the targeted area without contaminating and damaging the surrounding tissues. Low-frequency induction heating (LFIH) of catheters made out of biocompatible magnetic composites is an elegant solution. By inserting the catheter through the varicose to be treated and by exciting it through LFIH, it seems possible to reach a temperature high enough to properly heal the damaged area while preserving the surrounding healthy ones. Although recent published results seem promising, an optimized procedure is still required to achieve further improvements. Many directions lying on the active material formulation have been largely explored in the past (variations of particle content, nature, size, and shape). In this work, we propose an alternative solution, which involves the processing of ferromagnetic composites under a constant homogeneous magnetic field, leading to the strong anisotropic behavior due to particles alignment. Remarkably, experimental results demonstrate that by exciting such anisotropic composites along the alignment direction enhances the LFIH effect by more than 30%. Moreover, improvements can also be noticed in the perpendicular direction, meaning that the structured distribution is enough to increase the ferromagnetic properties. Furthermore, the resulting composite is highly flexible, making it easier to be integrated in several medical devices (e.g. endovenous thermal catheter, electromagnetic tracking system, and so on)