Fibre-reinforced composites as root canal posts

Fibre-reinforced composite (FRC) root canal posts are suggested to have biomechanical benefits over traditional metallic posts, but they lack good adhesion to resin composites. The aim of this series of studies was to evaluate the adhesion of individually formed fibre-reinforced composite material to composite resin and dentin, as well as some mechanical properties. Flexural properties were evaluated and compared between individually formed FRC post material and different prefabricated posts. The depth of polymerization of the individually formed FRC post material was evaluated with IR spectrophotometry and microhardness measurements, and compared to that of resin without fibres. Bonding properties of the individually formed FRC post to resin cements and dentin were tested using Pull-out- and Push-out-force tests, evaluated with scanning electron microscopy, and compared to those of prefabricated FRC and metal posts. Load-bearing capacity and microstrain were evaluated and failure mode assessment was made on incisors restored with individually formed FRC posts of different structures and prefabricated posts. The results of these studies show that the individually polymerized and formed FRC post material had higher flexural properties compared to the commercial prefabricated FRC posts. The individually polymerized FRC material showed almost the same degree of conversion after light polymerization as monomer resin without fibres. Moreover, it was found that the individually formed FRC post material with a semiinterpenetrating polymer network (IPN) polymer matrix bonded better to composite resin luting cement, than did the prefabricated posts with a cross-linked polymer matrix. Furthermore, it was found that, contrary to the other posts, there were no adhesive failures between the individually formed FRC posts and composite resin luting cement. This suggests better interfacial adhesion of cements to these posts. Although no differences in load-bearing capacity or microstrain could be seen, the incisors restored with individually formed FRC posts with a hollow structure showed more favourable failures compared to other prefabricated posts. These studies suggest that it is possible to use individually formed FRC material with semi-IPN polymer matrix as root canal post material. They also indicate that there are benefits especially regarding the bonding properties to composite resin and dentin with this material compared to prefabricated FRC post material with a cross-linked matrix. Furthermore, clinically more repairable failures were found with this material compared to those of prefabricated posts.

Lyotard y La condició postmoderna, Vint-i-cinc anys després

L"any 1979 Jean-François Lyotard (1924-1998) publicava a París La condition postmoderne. Rapport sur le savoir, editat per Les Éditions de Minuit, obra en què es retratava l"home postmodern i que amb el pas dels anys s"ha convertit en una mena de clàssic del pensament contemporani. La tesi de fons del llibre -una obra encarregada per les autoritats del Quebec- és ben coneguda: el saber canvia d"estatut al mateix temps que les societats entren en l"era anomenada postindustrial, segons havien anunciat Daniel Bell i Alain Touraine. Per tant, la qüestió del saber en aquesta època postindustrial -que a grans trets coincideix amb un esperit d"època (Zeitgeist) que es pot identifi car amb la postmodernitat- cal situar-la en la perspectiva de les societats industrials avançades.

The Challenges Of Implementing High Performance Work Practices In The Nonprofit Sector

The last economic crisis raised huge challenges for nonprofit organizations. It is now critical for nonprofit organizations to show not only their social legitimacy but also their efficiency and competency to claim for grants (Kearns, Bell, Deem, & McShane, 2012). High Performance Work Practices (HPWP) are a way to foster performance and thus to answer challenges nonprofit organizations are currently facing. However, such practices have until then only been considered for the corporate world. The entire philosophy behind nonprofit organizations contrasts radically from the for-profit sector. Human resources management in particular may differ as well. The aim of this article is precisely to analyze the challenges of implementing HPWP in nonprofit organizations. In order to explore those challenges, we study the HR practices of a nonprofit organization based in UK that struggles against poverty. Discussion of results highlights good practices that should be applied along the nonprofit sector.

Probabilistic electrical resistivity tomography of a CO2 sequestration analog

Electrical resistivity tomography (ERT) is a well-established method for geophysical characterization and has shown potential for monitoring geologic CO2 sequestration, due to its sensitivity to electrical resistivity contrasts generated by liquid/gas saturation variability. In contrast to deterministic inversion approaches, probabilistic inversion provides the full posterior probability density function of the saturation field and accounts for the uncertainties inherent in the petrophysical parameters relating the resistivity to saturation. In this study, the data are from benchtop ERT experiments conducted during gas injection into a quasi-2D brine-saturated sand chamber with a packing that mimics a simple anticlinal geological reservoir. The saturation fields are estimated by Markov chain Monte Carlo inversion of the measured data and compared to independent saturation measurements from light transmission through the chamber. Different model parameterizations are evaluated in terms of the recovered saturation and petrophysical parameter values. The saturation field is parameterized (1) in Cartesian coordinates, (2) by means of its discrete cosine transform coefficients, and (3) by fixed saturation values in structural elements whose shape and location is assumed known or represented by an arbitrary Gaussian Bell structure. Results show that the estimated saturation fields are in overall agreement with saturations measured by light transmission, but differ strongly in terms of parameter estimates, parameter uncertainties and computational intensity. Discretization in the frequency domain (as in the discrete cosine transform parameterization) provides more accurate models at a lower computational cost compared to spatially discretized (Cartesian) models. A priori knowledge about the expected geologic structures allows for non-discretized model descriptions with markedly reduced degrees of freedom. Constraining the solutions to the known injected gas volume improved estimates of saturation and parameter values of the petrophysical relationship. (C) 2014 Elsevier B.V. All rights reserved.

Neuronal activity controls the antagonistic between PGC-1α and SMRT in regulating antioxidant defences

Transcriptional coactivators and corepressors often have multiple targets and can have opposing actions on transcription and downstream physiological events. The coactivator peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α is under-expressed in Huntington's disease and is a regulator of antioxidant defenses and mitochondrial biogenesis. We show that in primary cortical neurons, expression of PGC-1α strongly promotes resistance to excitotoxic and oxidative stress in a cell autonomous manner, whereas knockdown increases sensitivity. In contrast, the transcriptional corepressor silencing mediator of retinoic acid and thyroid hormone receptors (SMRT) specifically antagonizes PGC-1α-mediated antioxidant effects. The antagonistic balance between PGC-1α and SMRT is upset in favor of PGC-1α by synaptic activity. Synaptic activity triggers nuclear export of SMRT reliant on multiple regions of the protein. Concommitantly, synaptic activity post-translationally enhances the transactivating potential of PGC-1α in a p38-dependent manner, as well as upregulating cyclic-AMP response element binding protein-dependent PGC-1α transcription. Activity-dependent targeting of PGC-1α results in enhanced gene expression mediated by the thyroid hormone receptor, a prototypical transcription factor coactivated by PGC-1α and repressed by SMRT. As a consequence of these events, SMRT is unable to antagonize PGC-1α-mediated resistance to oxidative stress in synaptically active neurons. Thus, PGC-1α and SMRT are antagonistic regulators of neuronal vulnerability to oxidative stress. Further, this coactivatorcorepressor antagonism is regulated by the activity status of the cell, with implications for neuronal viability.

Managing innovations in biotechnology

Estudi de la situació, estratègies i tendències de la gestió de les innovacions en biotecnologia. El projecte es desenvolupa amb participants de Polònia, França, Holanda i Espanya. Per tant, l'anàlisi té una perspectiva internacional, principalment centrada en els països esmentats. L'expliació teòrica contrasta amb un projecte de gestió real en una empresa de biotecnologia, amb les dades i la informació obtinguda en una visitat a una empresa de biotecnologia a Polònia

Investigação de Er3+ nos dois sítios cristalográficos de Gd2SiO5 através da fotoluminescência resolvida no tempo

Gadolinium oxyortho-silicate, Gd2SiO5, presents a monoclinic structure with two crystallographic sites in which Gd3+ ions are equally distributed with coordination numbers CN, 7 and 9, respectively. By doping this host with Er3+ it is possible to distinguish and attribute the two sites by means of lifetime determination of the 4S3/2 state, (in this case, Er3+ substitutes Gd3+ ions). Samples doped with 0.1 and 5.0% molar Er3+ were prepared by solid state reaction and characterized by X-ray Diffractometry, Vibrational and Electronic Absorption Spectroscopies, and Time Resolved Photoluminescence. Based on the experimental results, it is possible to verify that, for the 5,0% doped sample, the lifetime value of the 4S3/2 state of the erbium ion inserted in site 1, (CN = 9), is 2.7 ± 0.1 mus, and for the one inserted in site 2, (CN = 7), it is 1.5 ± 0.1 mus.

The interaction between mercury(II) and sulfathiazole

The interaction of mercury(II) with sulfathiazole has been analyzed. IR and NMR spectral studies suggest a coordination of Hg(II) with the Nthiazolic atom, unlike related Hg-sulfadrugs compounds. The complex was screened for its activity against Escherichia coli, showing an appreciable antimicrobial activity compared with the ligand.

The interaction between sulfathiazole and cobalt(II): potentiometric studies

Potentiometric studies of sulfathiazole (HST) in the presence and absence of cobalt(II) were performed. Equilibrium constants for the formation of the detected species, [Co(ST)]+ and [Co(ST)(OH)], are reported. UV-Vis spectrophotometric measurements suggest that the coordination Co(II)-sulfathiazole might be through a N atom, which, in agreement with MO calculations, could be a thiazolic one. In spite of sulfonamides being better ligands at pH >7, [Co(ST)]+ was found at pH » 3.

Pharmaceutical use of galactomannans

The pharmaceutical use of galactomannans from different sources, commercial and noncommercial, has been extensively studied over the past decade. Galactomannans show potential in the global trend towards the use of more plant-based products for ecological motives, and their production and application do not cause pollution or disturb the ecosystem. There is a variety of galactomannan sources and various pharmaceutical forms of application, such as tablets or capsules, hydrogels and films. Besides the simple use as inert excipient this polysaccharides play role in the modification of drug release, especially in colonic environmental, as a matrix or coating material.

Determination of polyphenol contents and antioxidant capacity of no-alcoholic red grape products (vitis labrusca) from conventional and organic crops

The polyphenol contents and antioxidant capacity of Brazilian red grape juices and wine vinegars were analyzed. Additionally, it was analyzed the human polyphenol absorption and acute effect in plasmatic oxidative metabolism biomarkers after juice ingestion. The organic Bordo grape juice (GBO) presented a higher level of trans-resveratrol, quercitin, rutin, gallic acid, caffeic acid and total flavonoids then other juices and vinegars as well as antioxidant capacity. The plasmatic polyphenol increased 27.2% after GBO juice ingestion. The results showed that juices and vinegars from Brazilian crops present similar chemical and functional properties described in studies performed in other countries.

Feministinen pedagogiikka rajojen ylittäjänä

Artikkelissa tarkastellaan Bell Hooksin kehittelemän feministisen pedagogiikan ideoita.

Validation of an hplc method for the determination of 1,7-dihydroxy-2,3-methylenedioxyxanthone in extracts obtained from Polygala cyparissias A. St. Hil. & Moq. (Polygalaceae) and evaluation of the influence of its content on the gastroprotective activity

Polygala cyparissias is a plant widespread in Southern Latin America. Recently, we demonstrated the gastroprotective activity of the extract, as well as for one of the isolated metabolites-1,7-dihydroxy-2,3-methylenedioxyxanthone (MDX). In this study, a HPLC method for the quantification of MDX was validated. The HPLC method was linear (0.5-24 µg mL-1 of MDX) with good accuracy, precision and robustness. The content of MDX in the extracts from whole and different parts of the plant ranged from 0 to 5.4 mg g-1 and the gastroprotective index ranged from 72.1 to 99.1%. Thus, the method might be used for the standardization of the extracts based on the MDX marker.

Simultaneous determination of four phenolic compounds in extracts of aerial parts of Ipomoea pes-caprae (L.) R. Br. (Convolvulaceae) by HPLC-UV

Among other applications, Ipomoea pes-caprae is popularly used to treat jellyfish stings, supporting the development of a product for dermatological use. Hydroethanolic spray-dried extract was chosen for the further development of phytomedicines, and a stability-indicative HPLC-UV method was developed and validated for the determination of isoquercitrin and isochlorogenic acids A, B and C. The method was developed using a C18 column (250 x 4.6 mm, 5 µm) with an acetonitrile:water mobile phase at pH 3.0 in a gradient run. The four constituents and other unidentified components of the extract were appropriately resolved without interference of degradation products after stress tests (acid, alkali, neutral, oxidant, photolysis). The method showed linearity in the isoquercitrin concentration range from 5.0-50.0 µg mL-1, with adequate precision (RSD% < 2.5% for the intra- and inter-day studies), accuracy (recovery of 100.0 ± 2.0%), and robustness. Both the herbal drug and spray-dried extract of I. pes-caprae were subjected to stability studies in accelerated and long-term conditions over four months. The samples maintained their characteristics and marker contents (< 10% of variation).