Controlling the isothermal crystallization of isodimorphic PBS-ran-PCL random copolymers by varying composition and supercooling

In this work, we study for the first time, the isothermal crystallization behavior of isodimorphic random poly(butylene succinate)-ran-poly(e-caprolactone) copolyesters, PBS-ran-PCL, previously synthesized by us. We perform nucleation and spherulitic growth kinetics by polarized light optical microscopy (PLOM) and overall isothermal crystallization kinetics by differential scanning calorimetry (DSC). Selected samples were also studied by real-time wide angle X-ray diffraction (WAXS). Under isothermal conditions, only the PBS-rich phase or the PCL-rich phase could crystallize as long as the composition was away from the pseudo-eutectic point. In comparison with the parent homopolymers, as comonomer content increased, both PBS-rich and PCL-rich phases nucleated much faster, but their spherulitic growth rates were much slower. Therefore, the overall crystallization kinetics was a strong function of composition and supercooling. The only copolymer with the eutectic composition exhibited a remarkable behavior. By tuning the crystallization temperature, this copolyester could form either a single crystalline phase or both phases, with remarkably different thermal propertiesPeer ReviewedPostprint (published version

Incentivos para una gestión forestal sostenible y refuerzo del papel de los boques como sumideros de CO2

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Multiscale modelling of thermoplastic woven fabric composites: From micromechanics to mesomechanics

The mechanical properties of woven composites can be predicted by using a multiscale modelling approach. The starting point to its application is the microscale (the level of fibres, matrix and interfaces), that allows the computation of the homogenised behaviour of the yarn. The aim of this work was to predict the yarn-level behaviour of a thermoplastic-based woven composite in order to allow the formulation of a representative constitutive model that can be used to predict ply properties at the mesoscale. To accomplish this purpose, an in situ characterisation of the microconstituents was carried out. This served to generate inputs for three different representative volume element (RVE) models that allowed predicting the yarn longitudinal, transverse and shear responses. These mechanical characteristics allowed the determination of homogenised yarn constitutive behaviour which was found to be characterised by significant non-linearity until failure, specially in transverse and shear directions.The research leading to the developments described received funding of the project ADVANSEAT; a collaborative R&D project led by Grupo Antolín, and partially supported by the Spanish Ministry of Economy, Industry and Competitiveness (MINECO). C.S. Lopes also acknowledges the support of MINECO through the Ramón y Cajal fellowship (RYC-2013-14271)

The effect of titanium dioxide surface modification on the dispersion, morphology, and mechanical properties of recycled PP/PET/TiO2 PBNANOs

Titanium dioxide (TiO2) nanoparticles have recently appeared in PET waste because of the introduction of opaque PET bottles. We prepare polymer blend nanocomposites (PBNANOs) by adding hydrophilic (hphi), hydrophobic (hpho), and hydrophobically modified (hphoM) titanium dioxide (TiO2) nanoparticles to 80rPP/20rPET recycled blends. Contact angle measurements show that the degree of hydrophilicity of TiO2 decreases in the order hphi > hpho > hphoM. A reduction of rPET droplet size occurs with the addition of TiO2 nanoparticles. The hydrophilic/hydrophobic balance controls the nanoparticles location. Transmission electron microscopy (TEM_ shows that hphi TiO2 preferentially locates inside the PET droplets and hpho at both the interface and PP matrix. HphoM also locates within the PP matrix and at the interface, but large loadings (12%) can completely cover the surfaces of the droplets forming a physical barrier that avoids coalescence, leading to the formation of smaller droplets. A good correlation is found between the crystallization rate of PET (determined by DSC) and nanoparticles location, where hphi TiO2 induces the highest PET crystallization rate. PET lamellar morphology (revealed by TEM) is also dependent on particle location. The mechanical behavior improves in the elastic regime with TiO2 addition, but the plastic deformation of the material is limited and strongly depends on the type of TiO2 employed

Neoadjuvant intralesional methotrexate for juvenile xanthogranuloma in an adult

Juvenile xanthogranuloma (JXG) is a non-Langerhans cell histiocytosis usually occurring in infants and typically located in the head or neck.1 Clinically, solitary skin lesions are found in 60%–82% of patients and the most common variant is characterized by one yellowish nodule. Adult onset is rare, and although JXG is usually self-limiting in children, spontaneous resolution is uncommon at older ages. In addition, up to 50% of patients with spontaneous regression develop an atrophy or anetodermal area.2 Thus, complete excision is frequently performed in this population subgroup to achieve better cosmetic results. In disseminated forms, different chemotherapy regimens, corticosteroids and other systemic therapies are used. Herein, we report a case of adult JXG treated with intralesional methotrexate (MTX) resulting in a rapid reduction in size

Histone Acetylation-Mediated Regulation of the Hippo Pathway

The Hippo pathway is a signaling cascade recently found to play a key role in tumorigenesis therefore understanding the mechanisms that regulate it should open new opportunities for cancer treatment. Available data indicate that this pathway is controlled by signals from cell-cell junctions however the potential role of nuclear regulation has not yet been described. Here we set out to verify this possibility and define putative mechanism(s) by which it might occur. By using a luciferase reporter of the Hippo pathway, we measured the effects of different nuclear targeting drugs and found that chromatin-modifying agents, and to a lesser extent certain DNA damaging drugs, strongly induced activity of the reporter. This effect was not mediated by upstream core components (i.e. Mst, Lats) of the Hippo pathway, but through enhanced levels of the Hippo transducer TAZ. Investigation of the underlying mechanism led to the finding that cancer cell exposure to histone deacetylase inhibitors induced secretion of growth factors and cytokines, which in turn activate Akt and inhibit the GSK3 beta associated protein degradation complex in drug-affected as well as in their neighboring cells. Consequently, expression of EMT genes, cell migration and resistance to therapy were induced. These processes were suppressed by using pyrvinium, a recently described small molecule activator of the GSK 3 beta associated degradation complex. Overall, these findings shed light on a previously unrecognized phenomenon by which certain anti-cancer agents may paradoxically promote tumor progression by facilitating stabilization of the Hippo transducer TAZ and inducing cancer cell migration and resistance to therapy. Pharmacological targeting of the GSK3 beta associated degradation complex may thus represent a unique approach to treat cancer. © 2013 Basu et al

Occupational exposure to nano-TiO2 in the life cycle steps of new depollutant mortars used in construction

The present work is focused on the measurement of workers exposure to nano-TiO2 in the life cycle steps of depollutant mortars. It has been done in the framework of the SCAFFOLD project, which aims at the management of potential risks arising from the use of manufactured nanomaterials in construction. Main findings can be summarized as follows: (1) The occupational exposure to nano- TiO2 is below 0.3 mg/m3 for all measured scenarios. The highest concentrations were measured during the cleaning task (in the nano- TiO2 manufacturing process) and during the application (spraying) of depollutant coatings on a wall. (2) It was found a high release of particles above the background in several tasks as expected due to the nature of the activities performed. The maximum concentration was measured during drilling and during adding powder materials (mean total particle concentration up to 5.591E+04 particles/cm3 and 5.69E+04 particles/cm3). However, considering data on total particle concentration released, no striking differences have been observed when tasks have been performed using conventional materials in the sector (control) and when using materials doped with nano-objects.European Commission's FP