Time filter

Source Type

Sencadas V.,University of Minho | Martins P.,University of Minho | Pitaes A.,University of Minho | Pitaes A.,Polytechnic University of Valencia | And 5 more authors.
Langmuir | Year: 2011

This work reports on the nucleation of the β-phase of poly(vinylidene fluoride) (PVDF) by incorporating CoFe2O4 and NiFe 2O4 nanoparticles, leading in this way to the preparation of magnetoelectric composites. The fraction of filler nanoparticles needed to produce the same β- to α-phase ratio in crystallized PVDF is 1 order of magnitude lower in the cobalt ferrite nanoparticles. The interaction between nanoparticles and PVDF chains induce the all-trans conformation in PVDF segments, and this structure then propagates in crystal growth. The nucleation kinetics is enhanced by the presence of nanoparticles, as corroborated by the increasing number of spherulites with increasing nanoparticle content and by the variations of the Avrami's exponent. Further, the decrease of the crystalline fraction of PVDF with increasing nanoparticle content indicates that an important fraction of polymer chains are confined in interphases with the filler particle. © 2011 American Chemical Society.

Panagopoulou A.,National Technical University of Athens | Kyritsis A.,National Technical University of Athens | Sabater I Serra R.,Polytechnic University of Valencia | Gomez Ribelles J.L.,Polytechnic University of Valencia | And 4 more authors.
Biochimica et Biophysica Acta - Proteins and Proteomics | Year: 2011

Protein-water dynamics in mixtures of water and a globular protein, bovine serum albumin (BSA), was studied over wide ranges of composition, in the form of solutions or hydrated solid pellets, by differential scanning calorimetry (DSC), thermally stimulated depolarization current technique (TSDC) and dielectric relaxation spectroscopy (DRS). Additionally, water equilibrium sorption isotherm (ESI) measurements were performed at room temperature. The crystallization and melting events were studied by DSC and the amount of uncrystallized water was calculated by the enthalpy of melting during heating. The glass transition of the system was detected by DSC for water contents higher than the critical water content corresponding to the formation of the first sorption layer of water molecules directly bound to primary hydration sites, namely 0.073 (grams of water per grams of dry protein), estimated by ESI. A strong plasticization of the Tg was observed by DSC for hydration levels lower than those necessary for crystallization of water during cooling, i.e. lower than about 0.3 (grams of water per grams of hydrated protein) followed by a stabilization of Tg at about - 80 °C for higher water contents. The α relaxation associated with the glass transition was also observed in dielectric measurements. In TSDC a microphase separation could be detected resulting in double Tg for some hydration levels. A dielectric relaxation of small polar groups of the protein plasticized by water, overlapped by relaxations of uncrystallized water molecules, and a separate relaxation of water in the crystallized water phase (bulk ice crystals) were also recorded. © 2011 Elsevier B.V. All Rights Reserved.

Cervello I.,University of Valencia | Mas A.,University of Valencia | Gil-Sanchis C.,University of Valencia | Peris L.,University of Valencia | And 5 more authors.
PLoS ONE | Year: 2011

Endometrial regeneration is mediated, at least in part, by the existence of a specialized somatic stem cell (SSC) population recently identified by several groups using the side population (SP) technique. We previously demonstrated that endometrial SP displays genotypic, phenotypic and the functional capability to develop human endometrium after subcutaneous injection in NOD-SCID mice. We have now established seven human endometrial SP (hESP) cell lines (ICE 1-7): four from the epithelial and three from the stromal fraction, respectively. SP cell lines were generated under hypoxic conditions based on their cloning efficiency ability, cultured for 12-15 passages (20 weeks) and cryopreserved. Cell lines displayed normal 46XX karyotype, intermediate telomerase activity pattern and expressed mRNAs encoding proteins that are considered characteristic of undifferentiated cells (Oct-4, GDF3, DNMT3B, Nanog, GABR3) and those of mesodermal origin (WT1, Cardiac Actin, Enolase, Globin, REN). Phenotype analysis corroborated their epithelial (CD9+) or stromal (vimentin+) cell origin and mesenchymal (CD90+, CD73+ and CD45-) attributes. Markers considered characteristic of ectoderm or endoderm were not detected. Cells did not express either estrogen receptor alpha (ERα) or progesterone receptor (PR). The hESP cell lines were able to differentiate in vitro into adipocytes and osteocytes, which confirmed their mesenchymal origin. Finally, we demonstrated their ability to generate human endometrium when transplanted beneath the renal capsule of NOD-SCID mice. These findings confirm that SP cells exhibit key features of human endometrial SSC and open up new possibilities for the understanding of gynecological disorders such as endometriosis or Asherman syndrome. Our cell lines can be a valuable model to investigate new targets for endometrium proliferation in endometriosis. © 2011 Cervelló et al.

Nueda M.J.,University of Alicante | Tarazona S.,Prince Felipe Research Center | Tarazona S.,Polytechnic University of Valencia | Conesa A.,Prince Felipe Research Center
Bioinformatics | Year: 2014

Motivation: The widespread adoption of RNA-seq to quantitatively measure gene expression has increased the scope of sequencing experimental designs to include time-course experiments. maSigPro is an R package specifically suited for the analysis of time-course gene expression data, which was developed originally for microarrays and hence was limited in its application to count data.Results: We have updated maSigPro to support RNA-seq time series analysis by introducing generalized linear models in the algorithm to support the modeling of count data while maintaining the traditional functionalities of the package. We show a good performance of the maSigPro-GLM method in several simulated time-course scenarios and in a real experimental dataset.Availability and implementation: The package is freely available under the LGPL license from the Bioconductor Web site (http://bioconductor.org). © 2014 The Author.

Aguilar-Gallardo C.,Prince Felipe Research Center | Simon C.,Prince Felipe Research Center | Simon C.,University of Valencia
Seminars in Reproductive Medicine | Year: 2013

The stem cell field owes a great deal to the previous work conducted by embryologists and researchers devoted to reproductive medicine. The time is coming when this emerging field will pay off in the reproductive sciences by offering new avenues of understanding gametogenesis and early embryonic development. Human embryonic stem cells are pluripotent cells that proliferate in vitro while maintaining an undifferentiated state, and they are capable of differentiating into most cell types under appropriate conditions. Embryo-friendly approaches have been developed as new methods of obtaining human embryonic stem cells without destroying the embryo. Somatic stem cells have been identified and isolated from numerous adult organs and tissues to create a multipotent and autologous source of cells with established medical indications. Cell reprogramming is now a scientific fact, and induced pluripotent cells, a new pluripotent cell type, have been generated by the overexpression of specific genes from a myriad of differentiated adult cell types. Cancer is now considered a stem cell disease. Cancer stem cells share numerous features with normal stem cells including hallmarks properties such as self-renewal and undifferentiation. Therefore, the actual focus of ovarian cancer research on the cancer stem cell model should generate efficient and personalized treatment designs to improve treatment efficiency. © 2013 by Thieme Medical Publishers, Inc.

Discover hidden collaborations