Search results for "Spectroscopy."

Two-photon excitation microscopy of tryptophan-containing proteins.

2002

We have examined the feasibility of observing single protein molecules by means of their intrinsic tryptophan emission after two-photon excitation. A respiratory protein from spiders, the 24-meric hemocyanin, containing 148 tryptophans, was studied in its native state under almost in vivo conditions. In this specific case, the intensity of the tryptophan emission signals the oxygen load, allowing one to investigate molecular cooperativity. As a system with even higher tryptophan content, we also investigated latex spheres covered with the protein avidin, resulting in 340 tryptophans per sphere. The ratio of the fluorescence quantum efficiency to the bleaching efficiency was found to vary b…

Cobalt content of foods and diets in a Spanish population

1986

The WHO Expert Committee on Food Contaminants has pointed out the need of determining the content of foods in trace elements in order to ascertain their contribution to the total intake of oligoelements through the diet. Since the contents in trace elements depend on the environmental features, it is necessary to carry out systematic determinations of trace elements in foods of local origin in order to know the exposure level of population. This work intends to study the cobalt contribution through the diet. The element intake is calculated from the cobalt content in raw foods after elimination of the non-eatable moiety by flame atomic absorption spectroscopy, after formation of a chelate w…

Detection ofEPOgene doping in blood

2012

Gene doping--or the abuse of gene therapy--will continue to threaten the sports world. History has shown that progress in medical research is likely to be abused in order to enhance human performance. In this review, we critically discuss the progress and the risks associated with the field of erythropoietin (EPO) gene therapy and its applicability to EPO gene doping. We present typical vector systems that are employed in ex vivo and in vivo gene therapy trials. Due to associated risks, gene doping is not a feasible alternative to conventional EPO or blood doping at this time. Nevertheless, it is well described that about half of the elite athlete population is in principle willing to risk …

Photodynamics of a Molecular Water-Soluble Nanocluster Identified as Au130(pMBA)50

2015

Photodynamics of a highly monodisperse sample of a water-soluble gold nanocluster tentatively identified as Au130(pMBA)50 (pMBA = p-mercaptobenzoic acid) was studied by mid-IR transient absorption spectroscopy with visible excitation. The observed long-lived excited states (>1 ns) indicate a molecular behavior of the cluster. By combining the transient absorption data with DFT calculation results the observed relaxation dynamics could be fully explained by identifying several relaxation processes involving singlet and triplet manifolds. The results indicate that the cluster may have interesting transient magnetic properties due to a long-lived triplet population.

From the spherical top to the asymmetric top

2004

This habilitation report presents a synthesis of my research work during the last 14 years. I have distinguished my experimental activities (part III), my theoretical work on the spectroscopy of quasi-spherical tops (part IV) and that concerning the spectroscopy of molecules trapped in solids (part V).

Downregulation of the Astroglial Connexin Expression and Neurodegeneration after Pilocarpine-Induced Status Epilepticus

2022

Astrocytic networks and gap junctional communication mediated by connexins (Cxs) have been repeatedly implicated in seizures, epileptogenesis, and epilepsy. However, the effect of seizures on Cx expression is controversial. The present study focused on the response of Cxs to status epilepticus (SE), which is in turn an epileptogenic insult. The expression of neuronal Cx36 and astrocytic Cx30 and Cx43 mRNAs was investigated in the brain of rats in the first day after pilocarpine-induced SE. In situ hybridization revealed a progressive decrease in Cx43 and Cx30 mRNA levels, significantly marked 24 h after SE onset in neocortical areas and the hippocampus, and in most thalamic domains, whereas…

Influence of post formation proceses on electrochemical and photoelectrochemical behaviour of TiO2 nanotubes

2011

β Decay of 127Cd and Excited States in 127In

2019

A dedicated spectroscopic study of the β decay of 127Cd was conducted at the IGISOL facility at the University of Jyväskylä. Following high-resolution mass separation in a Penning trap, β−γ−γcoincidences were used to considerably extend the decay scheme of 127In. The β-decaying 3/2+ and 11/2− states in 127Cd have been identified with the 127Cd ground state and the 283-keV isomer. Their respective half-lives have been measured to 0.45(128)s and 0.36(4) s. The experimentally observed βfeeding to excited states of 127In and the decay scheme of 127In are discussed in conjunction with large-scale shell-model calculations. peerReviewed

Gas phase behavior of radical cations of perfluoroalkyl-1,2,4-triazines: an experimental and theoretical study

2009

Electron ionization mass spectrometry and low-energy collision-induced decomposition reactions occurring in a tridimensional ion trap, together with density functional theory (DFT) calculations on neutrals, even- and odd-electron cations, have been used to study the gas-phase ion chemistry of a series of perfluoroalkyl-1,2,4-triazines. Loss of oxygen, due to thermal degradation occurring before ionization, likely involving the hydroxylamino group, has been observed. Compounds having a carbonyl group at position 6 of the triazine ring fragment in the source by elimination of NO followed by HF or CO. The decomposition pathways occurring due to CID experiments have shown interesting features d…

Phosphotungstic acid (PTA) in the synthesis of 3D CdS superstructures by diffusion assisted hydrothermal method

2015

Abstract In this study, the synthesis of cadmium sulfide (CdS) microstructures by gas diffusion assisted hydrothermal method using phosphotungstic acid (PTA) is reported. The as-synthesized products were characterized by Fourier transform infrared (FTIR), powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effects of PTA dose, thioacetamide amount, time and temperature on the morphology of obtained particles have been studied. In this process, PTA ion host stabilizes the CdS particles against aggregation and thioacetamide plays two roles, being at the same time a sulfur source and a capping ligand. Based on the performed analyses it seems that the thioacetamide is mor…