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showing 10 items of 698 documents
One-Dimensional TiO2-B Crystals Synthesised by Hydrothermal Process and Their Antibacterial Behaviour on Escherichia coli
2016
We have successfully synthesised one-dimensional single crystals of monoclinic phase titanium dioxide nanostructures (TiO2-B), prepared by a hydrothermal process. Morphological characterization was carried out by atomic force and scanning and transmission electron microscopy techniques. In order to study the crystalline structure, samples were calcined at 500°C in an air-filled chamber. X-ray diffraction results indicated that as-prepared samples presented diffraction patterns of hydrate hydrogen titanate and those calcined at 500°C exhibited the TiO2-B and anatase phases, confirmed by Raman spectroscopy. Scanning electron microscopy results showed that the one-dimensional nanostructures ha…
Anthracene Fluorescence Quenching by a Tetrakis (Ketocarboxamide) Cavitand
2014
Quenching of both fluorescence lifetime and fluorescence intensity of anthracene was investigated in the presence of a newly derived tetrakis (ketocarboxamide) cavitand at various concentrations. Time-correlated single photon counting method was applied for the lifetime measurements. A clear correlation between the fluorescence lifetime of anthracene as a function of cavitand concentration in dimethylformamide solution was observed. The bimolecular collisional quenching constant was derived from the decrease of lifetime. Fluorescence intensity was measured in the emission wavelength region around 400 nm as a result of excitation at 280 nm. Effective quenching was observed in the presence of…
Antioxidant activity and cardioprotective effect of a nonalcoholic extract of Vaccinium meridionale Swartz during ischemia-reperfusion in rats
2013
Our objective was to assess the antioxidant properties and the effects against the reperfusion injury of a nonalcoholic extract obtained by fermentation from the Colombian blueberry, mortiño (Vaccinium meridionale Swartz, Ericaceae). Antioxidant properties were assessed by in vitro systems. To examine the postischemic myocardial function, isolated rat hearts were treated 10 min before ischemia and during the first 10 min of reperfusion with the extract. To analyze the participation of nitric oxide (NO), other experiments were performed in the presence of nitric oxide synthase (NOS) inhibition with NG-nitro-L-arginine methyl ester (L-NAME). In cardiac tissue thiobarbituric acid reactive subs…
Chemical Profiling of Polyfloral Belgian Honey: Ellagic Acid and Pinocembrin as Antioxidants and Chemical Markers
2017
Chemical profiling of northern Belgian polyfloral honeys was performed to analyse their phenolic compound content (flavonoids and phenolic acids). First, samples were subjected to a standard analysis of their physicochemical properties, and then, the phenolic fraction was isolated and analysed using a HPLC/PAD method. All of the tested honeys showed a common and specific phenolic profile that could be the basis for the differentiation of polyfloral honeys of the Antwerp region from other polyfloral honeys. Chromatographic data indicated a high content of ellagic acid (9.13–13.66 mg/100 g honey), as well as the flavonoid pinocembrin (1.60–1.85 mg/100 g honey) in these honeys. Ellagic acid, a…
PTEN Mediates the Antioxidant Effect of Resveratrol at Nutritionally Relevant Concentrations
2014
Introduction.Antioxidant properties of resveratrol have been intensively studied for the last years, bothin vivoandin vitro. Its bioavailability after an oral dose is very low and therefore it is very important to make sure that plasma concentrations of free resveratrol are sufficient enough to be active as antioxidant.Aims.In the present study, using nutritionally relevant concentrations of resveratrol, we aim to confirm its antioxidant capacity on reducing peroxide levels and look for the molecular pathway involved in this antioxidant effect.Methods.We used mammary gland tumor cells (MCF-7), which were pretreated with different concentrations of resveratrol for 48 h, and/or a PTEN inhibit…
Adjuvant Chemoradiation Therapy in Gastric Cancer: Critically Reviewing the Past and Visualizing the Next Step Forward
2015
Gastric cancer remains one of the most common malignancies worldwide. Despite the significant advances in surgical treatment and multimodality strategies, prognosis has modestly improved over the last two decades. Locoregional relapse remains one of the main issues and the combined chemoradiation treatment seems to be one of the preferred approaches. However, more than ten years after the hallmark INT-0116 trial, minimal progress has been made both in terms of effectiveness and toxicity. Moreover, new regimens added to combined therapy failed to prove favourable results. Herein, we attempt a thorough literature review comparing pros and cons of all relative studies and potential bias, targe…
Use of Specific Chemical Reagents for Detection of Modified Nucleotides in RNA
2011
Naturally occurring cellular RNAs contain an impressive number of chemically distinct modified residues which appear posttranscriptionally, as a result of specific action of the corresponding RNA modification enzymes. Over 100 different chemical modifications have been identified and characterized up to now. Identification of the chemical nature and exact position of these modifications is typically based on 2D-TLC analysis of nucleotide digests, on HPLC coupled with mass spectrometry, or on the use of primer extension by reverse transcriptase. However, many modified nucleotides are silent in reverse transcription, since the presence of additional chemical groups frequently does not change …
Diabetic Foot Syndrome as a Possible Cardiovascular Marker in Diabetic Patients
2015
Diabetic foot ulcerations have been extensively reported as vascular complications of diabetes mellitus associated with a high degree of morbidity and mortality; in fact, some authors showed a higher prevalence of major, previous and new-onset, cardiovascular, and cerebrovascular events in diabetic patients with foot ulcers than in those without these complications. This is consistent with the fact that in diabetes there is a complex interplay of several variables with inflammatory metabolic disorders and their effect on the cardiovascular system that could explain previous reports of high morbidity and mortality rates in diabetic patients with amputations. Involvement of inflammatory marke…
Polymer/QDs Nanocomposites for Waveguiding Applications
2012
In this paper we review our recent progress in a still young type of active waveguides based on hybrid organic (polymer)—inorganic (semiconductor quantum dots) materials. They can be useful for the implementation of new photonic devices, because combining the properties of the semiconductor nanostructures (quantum size carrier confinement and temperature independent emission) with the technological capabilities of polymers. These optical waveguides can be easily fabricated by spin-coating and UV photolithography on many substrates (SiO2/Si, in the present work). We demonstrate that it is possible to control the active wavelength in a broad range (400–1100 nm), just by changing the base quan…
Drosophila melanogaster Models of Friedreich’s Ataxia
2018
Friedreich’s ataxia (FRDA) is a rare inherited recessive disorder affecting the central and peripheral nervous systems and other extraneural organs such as the heart and pancreas. This incapacitating condition usually manifests in childhood or adolescence, exhibits an irreversible progression that confines the patient to a wheelchair, and leads to early death. FRDA is caused by a reduced level of the nuclear-encoded mitochondrial protein frataxin due to an abnormal GAA triplet repeat expansion in the first intron of the human FXN gene. FXN is evolutionarily conserved, with orthologs in essentially all eukaryotes and some prokaryotes, leading to the development of experimental models of this…