Dually sensitive dextran-based micelles for methotrexate delivery

Temperature-sensitive polymeric micelles were prepared from dextran grafted with poly(N-isopropylacrylamide) (PNIPAAm) or polyethylene glycol methyl ether (PEGMA) via controlled radical polymerization and evaluated as delivery systems of the anticancer drug methotrexate (MTX). Polymer-grafting was carried out after introduction of initiating groups onto the polysaccharide backbone, without the need for protection of hydroxyl groups and avoiding the use of toxic solvents. Temperature-responsive dextran-based copolymers were designed to exhibit self-aggregation behaviour, affinity for MTX and high cellular internalization. In addition, some grafted polymers incorporated 2-aminoethyl methacrylate to reinforce MTX encapsulation in the micelles by means of ionic interactions. Dextran-based micelles were cytocompatible and had an appropriate size to be used as drug carriers. MTX release was dependent on the pH and temperature. The combination of poly(2-aminoethylmethacrylate) and PNIPAAm with the dextran backbone permitted the complete release of MTX at normal physiological temperature. Co-polymer micelles were highly internalized by tumour cells (CHO-K1) and, when loaded with MTX, led to enhanced cytotoxicity compared to the free drug

Chiral properties of hematite ({\alpha}-Fe2O3) inferred from resonant Bragg diffraction using circularly polarized x-rays

Chiral properties of the two phases - collinear motif (below Morin transition temperature, TM=250 K) and canted motif (above TM) - of magnetically ordered hematite ({\alpha}-Fe2O3) have been identified in single crystal resonant x-ray Bragg diffraction, using circular polarized incident x-rays tuned near the iron K-edge. Magneto-electric multipoles, including an anapole, fully characterize the high-temperature canted phase, whereas the low-temperature collinear phase supports both parity-odd and parity-even multipoles that are time-odd. Orbital angular momentum accompanies the collinear motif, while it is conspicuously absent with the canted motif. Intensities have been successfully confronted with analytic expressions derived from an atomic model fully compliant with chemical and magnetic structures. Values of Fe atomic multipoles previously derived from independent experimental data, are shown to be completely trustworthy

Synthesis of temperature-responsive Dextran-MA/PNIPAAm particles for controlled drug delivery using superhydrophobic surfaces

Purpose: To implement a bioinspired methodology using superhydrophobic surfaces suitable for producing smart hydro- gel beads in which the bioactive substance is introduced in the particles during their formation. Methods: Several superhydrophobic surfaces, including polystyrene, aluminum and copper, were prepared. Polymeric solutions composed by photo-crosslinked dextran-methacrylated and thermal responsive poly(N-isopropylacrylamide) mixed with a protein (insulin or albumin) were dropped on the superhydrophobic surfaces, and the obtained millimetric spheres were hardened in a dry environment under UV light. Results: Spherical and non-sticky hydrogels particles were formed in few minutes on the superhydrophobic surfaces. The proteins included in the liquid formulation were homogeneously distributed in the particle network. The particles exhibited temperature-sensitive swelling, porosity and protein release rate, with the responsiveness tunable by the dextran-MA/PNIPAAm weight ratio.Conclusions: The proposed method permitted the preparation of smart hydrogel particles in one step with almost 100% encapsulation yield. The temperature-sensitive release profiles suggest that the obtained spherical-shaped biomaterials are suitable as protein carriers. These stimuli-responsive beads could have potential to be used in pharmaceutical or other biomedical applications, including tissue engineering and regenerative medicine.The authors acknowledge funding from the project: PTDC/QUI/68804/2006 (FCT), IBEROMARE-Procept, FEDER and MICINN (SAF2008-01679). The research leading to these results has also received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement #NMP4-SL-2009-229292. The authors are grateful to project DISC REGENERATION, Collaborative Project-Large-scale integrating project, NMP3-LA-2008-213904 for the use of the UV lamp

Eco-trench: a novel trench solution based on reusing excavated material and a finishing layer of expansive concrete

Installing utility pipelines generates a significant amount of trench arisings, which are usually transported to landfills instead of being reused as backfill material. This practice generates CO 2 emissions and wastes raw materials. This paper presents a more sustainable solution, an eco-trench, which is based on re-using trench arisings as backfill and adding a top layer of expansive concrete to improve the eco-trench's structural performance. The technical feasibility of the eco-trench was evaluated through a finite element model, which identified the degree of expansion in concrete required to avoid failure or subside the stresses caused by traffic. The potential expansion of concrete was measured under confined conditions in the laboratory by means of a novel test developed for this purpose. The results showed that adding calcium oxide generates the required internal stress. The results were then confirmed in a pilot experience

Lived Experiences of Filipino Male Occupational Therapy Students

The historical dominance of women working in occupational therapy, coupled with the underrepresentation of males in the field globally, creates a need to investigate the experiences of male students in occupational therapy programs. In the context of the Philippines, where women make up 74.72% of the occupational therapy workforce, this study aims to address the following scaffolding problem by exploring the experiences and motivations of male students in Philippine occupational therapy programs. This study seeks to shed light on the factors influencing their educational journey and contribute to a better understanding of gender dynamics within the field. A qualitative design was used. Nine male occupational therapy students from various universities across the Philippines completed a survey questionnaire developed by the authors and attended a focus group discussion. Qualitative data was recorded and analyzed using thematic analysis. Upon analysis, five themes emerged: (1) Means and Not the End, (2) Rapport and Communication, (3) Society and Stereotyping, (4) Introspection of Male Students, and (5) Furtherance of Gender Inclusivity. The findings suggest that there are roles and expectations specific to male occupational therapy students within the Philippines, which may differ to some extent from those of their female counterparts. The participants experienced particular challenges and opportunities due to their gender. These results may be used to understand the existing gender disparity still present in different occupational therapy workforces

Epidemiología de las fracturas de la extremidad proximal del fémur en asturias

Hemos realizado un estudio epidemiológico de las fracturas de fémur proximal en personas mayores de 50 años, atendidas en nuestro Hospital durante los años 1990-92. Se valoraron un total de 355 casos. En el período estudiado se observó que las fracturas más numerosas fueron la cervicales, no encontrando diferencias significativas en los ingresos según el período estacional. La edad media de presentación fue de 81 años. La tasa de incidencia fue muy semejante a las otras provincias españolas y menor que la encontrada en los países del Norte de Europa, Inglaterra y Estados Unidos.We have performed an epidemiologic study on the incidence of proximal femoral fractures in patients older than 50 years, all reviewed in our Hospital from 1990 to 1992. We included 355 patients. Femoral neek fractures were the most frequent lesions. No significant differences in the hospital admissions were found during all the year's seasons. The mean age of presentation was 81 years. The incidence rate was similar to the rest of Spain, and less than in North Europe, England and United States

Removal of sialic acid from bull sperm decreases motility and mucus penetration ability but increases zona pellucida binding and polyspermic penetration in vitro

peer-reviewedThis study tested the hypothesis that sperm sialic acid (Sia) is required to reach the site of fertilization, and that successful fertilization requires recognition of Sia from both the sperm and oocyte to occur. In addition, it has recently been reported that Siglecs (Sia-binding-immunoglobulin-like lectins) are present on the sperm surface. Thus, the possibility that the recognition of oocyte Sia was sperm-Siglec-mediated was also addressed. Sperm exposed to neuraminidase (NMase) exhibited lower overall and progressive motility, which translated to a decreased ability to swim through cervical mucus from cows in oestrus. In addition, when either sperm or cumulus-oocyte complexes (COCs) were treated with NMase, a decrease in cleavage and blastocyst rate was observed. However, incubation of sperm with increasing concentrations of anti-Siglec-2, -5, -6 and -10 antibodies prior to fertilization had no effect on their fertilizing ability. Interestingly, treatment with NMase increased the number of sperm bound to the ZP but also the rate of polyspermic fertilization. Flow cytometry analysis revealed no differences in the percentage of capacitated or acrosome-reacted sperm. These results suggest that Sia are required to reach the site of fertilization but need to be removed for sperm-oocyte interaction. However, fine regulation is needed to avoid abnormal fertilization which can lead to impaired embryo development