Search results for " Stab"
showing 10 items of 1773 documents
New approach for synthesis of poly(ethylglyoxylate) using Maghnite-H + , an Algerian proton exchanged montmorillonite clay, as an eco-catalyst
2017
International audience; In this works, we have explored a new method for a green synthesis of poly(ethylglyoxylate) (PEtG). This method consists on using a montmorillonite clay called Maghnite-H+ as an eco-catalyst to replace triethylamine which is toxic. Cationic polymerization experiments are performed in bulk conditions at three temperatures (-40 degrees C, 25 degrees C, 80 degrees C) and in THF solutions at room temperature (25 degrees C). At 25 degrees C, an optimum ratio of 5 wt% of catalyst leads to molar masses up to 22000 g/mol in THF solutions. Polymerizations in bulk conditions lead to slightly lower masses than experiments conducted in THF solutions. However, bulk polymerization…
GRID STABILITY IMPROVEMENT BY RES-BASED GENERATORS AND BATTERY ENERGY STORAGE SYSTEMS IN SMALL ISLANDS
2021
The integration of Renewable Energy Sources (RES) with power electronics interface to the grid, without the back-up of rotating inertia, endangers frequency stability. This issue becomes particularly critical in isolated power systems, like those of small islands not supplied by the main grid, in the case of high shares of production from unpredictable renewables such as photovoltaic and wind sources. Consequently, to preserve the security and the reliability of these systems, it is necessary to adopt new frequency adjustments mechanisms. In this context, the thesis investigates the transition toward an economically and technically feasible generating system based on RES, to achieve specifi…
Isolation of carcinoembryonic antigen N-terminal domains (N-A1) from soluble aggregates
2011
Abstract Carcinoembryonic antigen (CEA) was identified as a prominent tumor-associated antigen in human colorectal cancer and it is still intensively investigated. However, its physiological role remains unclear. The CEA molecule is composed of seven highly hydrophobic, immunoglobulin-like domains, six of which contain a single disulphide bridge. The production of recombinant protein containing Ig-like domains in bacterial expression systems often results in partial degradation or insolubility due to aggregation hampering the analysis of their native structure and function. Here, we present a new method of expression and purification of CEA N-terminal domains (N-A1) fused to MBP in Escheric…
Paediatric oral formulations: comparison of two extemporaneously compounded suspensions from tacrolimus capsules
2011
Study objectives: The objective of this study was to determine the stability of tacrolimus in extemporaneously compounded liquid formulations. Methods: Two sets of liquid formulations were prepared using two different vehicles: one set in sterile water and in simple syrup (1:1) and one set using equal volumes of commercially available suspending agent (Ora-Plus) and simple syrup. The concentration of tacrolimus in each formulation was 0.5 mg/mL. The preparations containing Ora-Plus were stored at 25°C, the formulations that were prepared with sterile water and simple syrup were stored under refrigeration at 4°C. Results: Samples were collected at regular time intervals over a period of 56 d…
An exploration of isotopic variability in feathers and claws of Lesser Kestrel Falco naumanni chicks from southern Sicily
2016
Stable isotopes are nowadays commonly used in the study of many key features of avian ecology. However, the adequate choice of what isotopic ratio to consider and what tissues to sample for assessing specific questions may be tricky. Here, we explored the variation in a suite of stable isotope ratios (δ13C, δ15N, δ34S, δ2H, δO) in the feathers and claws of chicks of Lesser Kestrels Falco naumannifrom south-eastern Sicily (Italy) sampled throughout colonies of the same population but surrounded by different habitats. Ouraimsare to provide an insight into the isotopic ecology of Lesser Kestrel and to provide methodological indications for futurestudies.Specifically,we tested whether stable is…
Probing a Polar Cluster in the Retinal Binding Pocket of Bacteriorhodopsin by a Chemical Design Approach
2012
Bacteriorhodopsin has a polar cluster of amino acids surrounding the retinal molecule, which is responsible for light harvesting to fuel proton pumping. From our previous studies, we have shown that threonine 90 is the pivotal amino acid in this polar cluster, both functionally and structurally. In an attempt to perform a phenotype rescue, we have chemically designed a retinal analogue molecule to compensate the drastic effects of the T90A mutation in bacteriorhodopsin. This analogue substitutes the methyl group at position C(13) of the retinal hydrocarbon chain by and ethyl group (20-methyl retinal). We have analyzed the effect of reconstituting the wild-type and the T90A mutant apoprotein…
Trace Element Concentration and Stable Isotope Ratio Analysis in Blueberries and Bilberries: A Tool for Quality and Authenticity Control
2021
Vaccinium genus berries—wild bilberries (Vaccinium myrtillus L.) and cultivated highbush blueberries (Vaccinium corymbosum L.)—are consumed worldwide, and their consumption has a trend of stable increase. Thus, considering their wide use in ethnomedicine, for juice and jam production, as functional food, as well as their use in preparations of extracts which have application potential in pharmaceutical and cosmetics industries, studies regarding the composition of these berries are of special importance. The aim of this study is to characterise the elemental and isotopic composition, as well as variation in element concentration in bilberries gathered from different sites in Northern Europe…
Interest, Voluntary Associations and the Stability of the Political System
1985
In this article the adequacy of the sociological paradigm in voluntary associ ations' research is investigated by comparing it with its nval, the incor poration or system integration paradigm (types 1 and 2) and with two approaches that are their combinations: multi-dimensional theones of disper sion and cross-cutting of interests (type 3) and multi-dimensional theories of incorporation and system integration of interests (type 4). I express the view that by themselves both pluralism and incorporation paradigms are , unable to depict the complex system of political stability. An adequate theory must contain elements of two dimensions of maintaining stability: firstly, the idea of dispersion…
5-methylcytosine modification of an Epstein–Barr virus noncoding RNA decreases its stability
2020
Many cellular noncoding RNAs contain chemically modified nucleotides that are essential for their function. The Epstein–Barr virus expresses two highly abundant noncoding RNAs called EBV-encoded RNA 1 (EBER1) and EBER2. To examine whether these viral RNAs contain modified nucleotides, we purified native EBERs from EBV-infected cells and performed mass spectrometry analysis. While EBER2 contains no modified nucleotides at stoichiometric amounts, EBER1 was found to carry 5-methylcytosine (m5C) modification. Bisulfite sequencing indicated that a single cytosine of EBER1 is methylated in ∼95% of molecules, and the RNA methyltransferase NSUN2 was identified as the EBER1-specific writer. Intrigui…
Numerically solving the relativistic Grad–Shafranov equation in Kerr spacetimes: numerical techniques
2018
The study of the electrodynamics of static, axisymmetric and force-free Kerr magnetospheres relies vastly on solutions of the so called relativistic Grad-Shafranov equation (GSE). Different numerical approaches to the solution of the GSE have been introduced in the literature, but none of them has been fully assessed from the numerical point of view in terms of efficiency and quality of the solutions found. We present a generalization of these algorithms and give detailed background on the algorithmic implementation. We assess the numerical stability of the implemented algorithms and quantify the convergence of the presented methodology for the most established setups (split-monopole, parab…