Search results for "21"

A library of monoalkenylsilsesquioxanes as potential comonomers for synthesis of hybrid materials

2018

In this paper we demonstrate a facile and efficient synthesis of monoalkenylsubstituted POSS compounds, i.e., R7(Si8O12)-alkenyl and R7(Si8O12)(OSiMe2)-alkenyl with a functional alkenyl group of chain length (from vinyl to dec-9-enyl, with or without additional –OSiMe2– spacer between the silsesquioxane core and alkenyl moiety) and with five types of inert groups (Et, iBu, iOc, Cy, Ph) at the POSS core. These compounds constitute a library of monosubstituted POSS systems, including thorough spectroscopic and thermal characteristics. These findings could be especially useful for material chemists applying the compounds as modifiers or comonomers for copolymerization reaction, e.g., with olef…

Thermal and thermo-oxidative stability and kinetics of decomposition of PHBV/sisal composites

2017

The decomposition behaviours of composites made of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and sisal were assessed in terms of thermal stability and decomposition kinetics, under inert and oxidative conditions, by means of multi-rate linear non-isothermal thermogravimetric experiments. A statistical design of experiments was applied to study the influence of the addition of sisal (0-10-20-30%wt), the presence coupling agent (Yes/No) and the applied conditions of work (inert or oxidative). An improvement of the thermal and thermo-oxidative stability of PHBV with the addition of sisal was observed for all cases. An accurate methodology based on iso-conversional methods was applied…

Applications and non-idealities of submicron Al–AlOx–Nb tunnel junctions

2016

We have developed a technique to fabricate sub-micron, 0.6µm×0.6µm Al-AlOx-Nb tunnel junctions using a standard e-beam resist, angle evaporation and double oxidation of the tunneling barrier, resulting in high quality niobium, as determined by the the high measured values of the critical temperature TC ∼ 7.5 K and the gap ∆ ∼ 1.3 meV. The devices show great promise for local nanoscale thermometry in the temperature range 1 - 7.5 K. Electrical characterization of the junctions was performed at sub-Kelvin temperatures both with and without an external magnetic field, which was used to suppress superconductivity in Al and thus bring the junction into a normal-metal-insulator-superconductor (NI…

Evaluation of web reinforcements in prestressed concrete box girders through shear-transverse bending domains

2020

In concrete box girders, the amount and distribution of reinforcements in the webs have to be estimated considering the local effects due to eccentric external loads and cross-sectional distortion and not only the global effect due to the resultant forces of a longitudinal analysis: shear, torsion and bending. This work presents an analytical model that allows designers to take into account the interaction of all these effects, global and local, for the determination of the reinforcements. The model is based on the theory of stress fields and it has been compared to a 3D finite element analysis, in order to validate the interaction domains. The results show how the proposed analytical mode…

Oxidation-responsive and "clickable" poly(ethylene glycol) via copolymerization of 2-(methylthio)ethyl glycidyl ether

2016

Poly(ethylene glycol) (PEG) is a widely used biocompatible polymer. We describe a novel epoxide monomer with methyl-thioether moiety, 2-(methylthio)ethyl glycidyl ether (MTEGE), which enables the synthesis of well-defined thioether-functional poly(ethylene glycol). Random and block mPEG-b-PMTEGE copolymers (Mw/Mn = 1.05-1.17) were obtained via anionic ring opening polymerization (AROP) with molecular weights ranging from 5 600 to 12 000 g·mol-1. The statistical copolymerization of MTEGE with ethylene oxide results in a random microstructure (rEO = 0.92 ± 0.02 and rMTEG E = 1.06 ± 0.02), which was confirmed by in situ 1H NMR kinetic studies. The random copolymers are thermorespon…

Thrombolysis Followed by Apixaban for Massive Pulmonary Embolism and Free-floating Thrombus in Right Ventricle in a Patient with Breast Cancer

2018

Free-floating thrombus in the right ventricle, associated with a massive acute pulmonary embolism (PE), is a rare phenomenon. PE is an important clinical entity with considerable mortality despite advances in diagnosis and treatment. The prognosis of PE depends on right ventricular dysfunction, myocardial injury markers, and early treatment. In this report, we present the case of a 71-year-old woman with a history of breast cancer admitted to intensive care unit for PE complicated by syncope. Although our case may seem complex because it is not represented in the guidelines, the result was satisfactory and showed how treatment with new anticoagulants (in this case apixaban) after massive th…

ACTO II / ACT II Mujeres / Women ¿Es gay la música de Chopin? Aspectos de la recepción de la música de Chopin en el siglo XIX

2021

Considering that it is difficult, if not impossible, for an analysis of Chopin?s music to unmask some aspects of his private life (such as an alleged sexual and affective attraction for individuals of his own sex), we can however argue that, throughout the 19th century, a connection was established between his work and a ?feminine universe.? That connection might have had implications in the way in which the feminized image of its author was constructed. The analysis of certain aesthetic and stylistic traits of Chopin?s music can help understand the causes of that perception.

Editorial: Thymic Epithelial Cells: New Insights Into the Essential Driving Force of T-Cell Differentiation.

2021

External Assessors as “Reviewers” for Quality Assurance of Open Access Journals

2017

Bending Work Time: Curvilinear Relationship Between Working Time Dimensions and Psychological and Somatic Symptoms.

2020

Objectives Study examines the curvilinear associations of working time dimensions (working hours, time pressure, work schedules, and control of work time and pace) on psychological and somatic symptoms. Methods Representative Finnish Quality-of-Work-Life Surveys conducted in 2003, 2008 and 2013 were restricted to those (N=11,165) regularly working over 10h/week with more than one-year tenure in their job. Generalised additive models were utilised in analysis. Results Working hours had U-shaped relationships with psychosomatic symptoms, while time pressure had a threshold effect. Work pace control had linear effect. The effects of work time control and work schedules were insignificant. Ther…