Search results for "Diss"

Electric Field Control of Spin-Dependent Dissipative Electron Transfer Dynamics in Mixed-Valence Molecules

2015

We demonstrate that the borderline class II/III magnetic MV dimers, which can be referred to as single molecule multiferroics, provide a unique possibility to achieve electric field control of the electron transfer (ET) dynamics. As an example, we consider a MV dimer d2-d1 in which an extra electron is delocalized over two spin-cores (s0 = 1/2), and the ET is spin-dependent due to the double exchange mechanism. It is assumed that the “extra” electron is coupled to the only intramolecular vibration, and a weak coupling to the dissipative subsystem (thermal bath) is taken into account. The vibronic energy levels and the wave functions of the isolated dimer (quantum part of the system) are num…

New binary solid dispersion of indomethacin with surfactant polymer: From physical characterization to in vitro dissolution enhancement

2009

This article investigated preparation of solid dispersions containing a poor water-soluble drug, indomethacin (IND), and a new surfactant polymer, polyoxyethylene 32 distearate (POED). Solid dispersions were prepared by the melting method and characterized by DSC, hot-stage microscopy (HSM), X-ray diffraction (XRD) and scanning electron microscopy (SEM). DSC and HSM analyses performed on IND/POED physical mixtures indicated that IND could dissolve in liquid POED. The materials showed complete miscibility at liquid state. Combination of DSC, XRD, and SEM revealed that these materials had limited miscibility at the solid state. Up to 20% w/w IND in POED, we did not detect significant modifica…

Effect of thickener on disintegration, dissolution and permeability of common drug products for elderly patients

2019

Dysphagia is a very common problem suffered by elderly patients. The use of thickeners during administration in these patients helps to prevent difficulties with swallowing larger solid dosage forms. However, there are several indications when the thickeners may influence disintegration and dissolution processes of solid dosage forms, potentially affecting therapeutic efficacy. In this paper the effects of a commonly used thickener on tablet disintegration, dissolution and subsequent absorption of 6 formulated drugs frequently used in elderly patients (Aspirin, Atenolol, Acenocumarol, Candesartan, Ramipril and Valsartan) in two different administration conditions (intact tablet and crushed …

Ketamine in acute phase of severe traumatic brain injury “an old drug for new uses?”

2021

AbstractMaintaining an adequate level of sedation and analgesia plays a key role in the management of traumatic brain injury (TBI). To date, it is unclear which drug or combination of drugs is most effective in achieving these goals. Ketamine is an agent with attractive pharmacological and pharmacokinetics characteristics. Current evidence shows that ketamine does not increase and may instead decrease intracranial pressure, and its safety profile makes it a reliable tool in the prehospital environment. In this point of view, we discuss different aspects of the use of ketamine in the acute phase of TBI, with its potential benefits and pitfalls.

Novel inulin-based mucoadhesive micelles loaded with corticosteroids as potential transcorneal permeation enhancers

2017

In this work a new copolymer of inulin (INU) derivatized with ethylendiamine (EDA) and retinoic acid (RA), named INU-EDA-RA, was synthetized, characterized and employed to produce micelles as carriers for topical administration of corticosteroids for the potential treatment of diseases of posterior eye segment. Spectroscopic analysis confirmed a molar derivatization degree of 11.30 and 4.30% in EDA and RA, respectively. INU-EDA-RA micelles are capable of strong mucoadhesive interactions which result time-independent and stable over time but concentration depending. Moreover micelles are able to encapsulate efficiently from 3 to 13% (w/w) of lipophilic drugs, as dexamethasone, triamcinolone …

Amorphous Ropinirole-Loaded Mucoadhesive Buccal Film: A Potential Patient-Friendly Tool to Improve Drug Pharmacokinetic Profile and Effectiveness

2020

Nowadays the therapeutic strategies to manage Parkinson&rsquo

Unraveling long-term changes in lake color based on optical properties of lake sediment

2020

A number of boreal surface waters have become browner over the last two decades. Recovery from acid rain is regarded as an important driver for this lake color increase, indicating a general browner lake color in preindustrial times. However, the lack of long-term monitoring data makes it challenging to unravel historical changes in lake color. In this study, we estimated long-term development in lake color (1800 to 2015) based on the optical properties of alkaline extractable dissolved organic matter (DOM) from sediment using UV–Vis and fluorescence spectroscopy. We found that the present lake color (2015) was significantly browner (four times higher in absorption coefficient) than for the…

Thermogalvanic effects on the corrosion of copper in heavy brine LiBr solutions

2012

Thermogalvanic corrosion of copper in heavy brine LiBr solutions has been investigated using a zero-resistance ammeter (ZRA). The temperature gradients between copper electrodes immersed in the same LiBr solution result in the formation of thermogalvanic cells with hot anodes, leading to high and sustained thermogalvanic currents. Copper loss rates, calculated using Faraday's law, substantially exceed 0.025mmyear -1, a value regarded as the threshold of low corrosion rates. The effects of thermogalvanic coupling on the surface properties of the anode and the cathode have been analysed by means of electrochemical impedance spectroscopy (EIS). The results obtained in this analysis have been r…

Ecotoxicological status of a watercourse recovering from heavy loading by pulp and paper industry

2013

Fungal genes related to calcium homeostasis and signalling are upregulated in symbiotic arbuscular mycorrhiza interactions

2012

Fluctuations in intracellular calcium levels generate signalling events and regulate different cellular processes. Whilst the implication of Ca2+ in plant responses during arbuscular mycorrhiza (AM) interactions is well documented, nothing is known about the regulation or role of this secondary messenger in the fungal symbiont. The spatio-temporal expression pattern of putatively Ca2+-related genes of Glomus intraradices BEG141 encoding five proteins involved in membrane transport and one nuclear protein kinase, was investigated during the AM symbiosis. Expression profiles related to successful colonization of host roots were observed in interactions of G. intraradices with roots of wild-ty…