Search results for "2-Photon"
showing 10 items of 19 documents
Aza-macrocyclic triphenylamine ligands for G-quadruplex recognition
2018
A new series of triphenylamine-based ligands with one (TPA1PY), two (TPA2PY) or three pendant aza-macrocycle(s) (TPA3PY) has been synthesised and studied by means of pH-metric titrations, UV/Vis spectroscopy and fluorescence experiments. The affinity of these ligands for G-quadruplex (G4) DNA and the selectivity they show for G4s over duplex DNA were investigated by Forster resonance energy transfer (FRET) melting assays, fluorimetric titrations and circular dichroism spectroscopy. Interestingly, the interactions of the bi- and especially the tri-branched ligands with G4s lead to a very intense redshifted fluorescence emission band that may be associated with intermolecular aggregation betw…
Direct observation of alpha-lactalbumin, adsorption and incorporation into lipid membrane and formation of lipid/protein hybrid structures
2019
The interaction between proteins and membranes is of great interest in biomedical and biotechnological research for its implication in many functional and dysfunctional processes. We present an experimental study on the interaction between model membranes and alpha-lactalbumin (alpha-La). alpha-La is widely studied for both its biological function and its anti-tumoral properties. We use advanced fluorescence microscopy and spectroscopy techniques to characterize alpha-La-membrane mechanisms of interaction and alpha-La-induced modifications of membranes when insertion of partially disordered regions of protein chains in the lipid bilayer is favored. Moreover, using fluorescence lifetime imag…
The TrkB agonist 7,8-dihydroxyflavone changes the structural dynamics of neocortical pyramidal neurons and improves object recognition in mice
2018
This is a pre-print of an article published in Brain Structure and Function. The final authenticated version is available online at: https://doi.org/10.1007/s00429-018-1637-x. BDNF and its receptor TrkB have important roles in neurodevelopment, neural plasticity, learning, and memory. Alterations in TrkB expression have been described in different CNS disorders. Therefore, drugs interacting with TrkB, specially agonists, are promising therapeutic tools. Among them, the recently described 7,8-dihydroxyflavone (DHF), an orally bioactive compound, has been successfully tested in animal models of these diseases. Recent studies have shown the influence of this drug on the structure of pyramidal …
Electronic and Functional Scope of Boronic Acid Derived Salicylidenehydrazone (BASHY) Complexes as Fluorescent Dyes
2017
[EN] A series of boronic acid derived salicylidenehydrazone (BASHY) complexes was prepared and photophysically characterized. The dye platform can be modified by (a) electronic tuning along the cyanine-type axis via modification of the donor-acceptor pair and (b) functional tuning via the boronic acid residue. On the one hand, approach (a) allows the control of photophysical parameters such as Stokes shift, emission color, and two-photon absorption (2PA) cross section. The resulting dyes show emission light-up behavior in nonpolar media and are characterized by high fluorescence quantum yields (ca. 0.5-0.7) and brightness (ca. 35000-40000 M-1 cm(-1)). Moreover, the 2PA cross sections reach …
Pulse trains produced by phase-modulation of ultrashort optical pulses: tailoring and characterization
2009
1094-4087; In this paper, creation of pulse doublets and pulse trains by spectral phase modulation of ultrashort optical pulses is investigated. Pulse doublets with specific features are generated through step-like and triangular spectral phase modulation, whereas sequences of pulses with controllable delay and amplitude are produced via sinusoidal phase modulations. A temporal analysis of this type of tailored pulses is exposed and a complete characterization with the SPIDER technique (Spectral Phase Interferometry for Direct Electric-field Reconstruction) is presented. (C) 2004 Optical Society of America.
Advanced fluorescence microscopy for in vivo imaging of neuronal activity
2019
Brain function emerges from the coordinated activity, over time, of large neuronal populations placed in different brain regions. Understanding the relationships of these specific areas and disentangling the contributions of individual neurons to overall function remain central goals for neuroscience. In this scenario, fluorescence microscopy has been proved as the tool of choice for in vivo recording of brain activity. Optical advances combined with genetically encoded indicators allow a large flexibility in terms of spatiotemporal resolution and field of view while keeping invasiveness in living animals to a minimum. Here we describe the latest advancements in the field of linear and nonl…
Search for neutralino pair production at root s = 189 GeV
2001
A search for pair-production of neutralinos at a LEP centre-of-mass energy of 189 GeV gave no evidence for a signal. This limits the neutralino production cross-section and excludes regions in the parameter space of the Minimal Supersymmetric Standard Model (MSSM).
Update of the search for supersymmetric particles in scenarios with Gravitino LSP and Sleptons NLSP
2001
An update of the search for sleptons, neutralinos and charginos in the context of scenarios where the lightest supersymmetric particle is the gravitino and the next-to-lightest supersymmetric particle is a slepton, is presented, together with the update of the search for heavy stable charged particles in light gravitino scenarios and Minimal Supersymmetric Standard Models. Data collected in 1999 with the DELPHI detector at centre-of-mass energies around 192, 196, 200 and 202 GeV were analysed. No evidence for the production of these supersymmetric particles was found. Hence, new mass limits were derived at 95% confidence level.
Search for supersymmetric particles in scenarios with a gravitino LSP and stau NLSP
2000
Sleptons, neutralinos and charginos were searched for in the context of scenarios where the lightest supersymmetric particle is the gravitino. It was assumed that the stau is the next-to-lightest supersymmetric particle. Data collected with the DELPHI detector at a centre-of-mass energy near 189 GeV were analysed combining the methods developed in previous searches at lower energies. No evidence for the production of these supersymmetric particles was found. Hence, limits were derived at 95% confidence level.
Treatment with Nicotine derived Nitrosamine Ketone NNK Causes Disruption of Blood Brain Barrier BBB and Microglia Activation in Mice
2022
4-Methylnitrosamino-1-(3-pyridyl)-1-butanone (NNK) is a nicotine metabolite produced within the tobacco plant, from combustion, and from metabolic breakdown. Cigarette Smoke (CS) continues to be a leading cause for decline of quality of life as well as deaths globally. While the link to poor health and eventually early death has been accepted for decades, it is increasingly recognized that smoking may contribute to a broad range of disorders. Epidemiologically, CS has been associated with neuroinflammation and several neurological disorders including Alzheimer’s disease, stroke, and multiple sclerosis. While direct links are not fully understood, studies in a humanized flow-based in vitro b…