Search results for "sers"
showing 10 items of 478 documents
High-power picosecond quasi-CW 1.3 µm Nd-laser passively modelocked using novel low-loss GaInNAs SBRs
2003
Singlet Excited-State Interactions in Naphthalene-Thymine Dyads
2004
Two thymidine-derived nucleosides 1 and 2 were prepared by attaching a chiral naphthalene to the positions 5′ and 3′ of the sugar. The resulting dyads, which contain key substructures present in drugs and nucleic acids, exhibit different spatial arrangements (transoid or cisoid) of the fluorophore relative to the thymine unit. Emission measurements on these compounds in the presence of ROH molecules revealed a remarkable intramolecular fluorescence quenching for dyad 1. The obtained results are consistent with quenching of the singlet excited state of 1 by hydrogen-bond donor solvents. Thus, a physical deactivation process (vibronically induced internal conversion) would be the pathway resp…
Aerosols generation using Er,Cr:YSGG laser compared to rotary instruments in conservative dentistry: A preliminary study
2021
Background In restorative dentistry, the use of high-speed air turbine, which generates aerosols, can be associated with the transmission of airborne diseases. New laser technologies could be useful in reducing the amount of aerosols, but there is a lack of scientific research on this topic. Material and methods This is a descriptive study to analyze the amount of aerosols produced after class I cavity preparation using high-speed air turbine (group 1) and Er,Cr:YSGG laser with two different parameters (groups 2 and 3). Fluorescein dye was incorporated into the coolant reservoir in order to visualize the production of aerosols during each procedure. Tooth preparation was performed in a typo…
Effect of diode laser irradiation on the attachment rate of periodontal ligament cells: an in vitro study.
2001
The present study is part of a basic research program investigating the cellular effects of an 810 nm GaAlAs-diode laser on human periodontal tissues. The aim of the investigation was to evaluate the effects of laser treatment of root surface specimens on the attachment of periodontal ligament (PDL) cells in vitro.Root specimens were prepared from periodontally diseased teeth. PDL cells were obtained from human third molar ligaments. Cells were cultured under simple, standardized, and reproducible experimental conditions. One hundred fifty root specimens were scaled and root planed with curets followed by air-powder abrasive treatment; 75 were then lased and 75 served as controls. The irrad…
Effects of maxillary protraction determined by laser metrology
1990
In this work we studied some of the main effects of the maxillary protraction orthopedic device. The initial dento-craniofacial reactions induced by maxillary protraction similar to that commonly employed in clinical practice are reported. The fringe counting holographic interferometry technique is used to measure displacements. The experiments were performed on a dried human skull; traction application points were situated over the permanent lateral incisors or over the first permanent molars. The results fundamentally reveal an anterior rotation of the dentomaxillary complex, more intense when traction is applied to the lateral incisors, as shown by a more marked extrusion of the molars i…
Photon scattering as a probe of microviscosity and channel size in gels such as sickle haemoglobin.
1983
The aggregation of sickle-cell haemoglobin (HbS) is one of the most physiologically important and widely studied macromolecular gelation processes. Both the thermodynamics and kinetics of the process are important in determining the pathological consequences of deoxygenation of the red cells (and both must be understood if a rational strategy is to be developed for pharmacological intervention). We describe here a new and versatile technique for the study of the structure and formation of the HbS aggregates, that should be widely applicable to gel systems generally. We use laser autocorrelation spectroscopy to observe the diffusion of monodisperse polystyrene latex spheres in the interstice…
What Motivates Internet Users to Search for Asperger Syndrome and Autism on Google?
2020
Social campaigns are carried out to promote autism spectrum disorder (ASD) awareness, normalization, and visibility. The internet helps to shape perceptions of Asperger syndrome and autism. In fact, these campaigns often coincide with the increase in searches for both diagnoses on Google. We have two study objectives: to use Google Trends to identify the annual time points from 2015 to 2019 with the highest Google search traffic in Spain for the terms &ldquo
NFC-maksaminen : mahdollisuudet ja haasteet käyttäjän näkökulmasta
2013
Mobiilit päätelaitteet ja niitä käyttävien kuluttajien määrä on lisääntynyt nopeasti viime vuosien aikana, mikä tuo uusia mahdollisuuksia erilaisille mobiilin maksamisen sovelluksille. Tässä tutkielmassa paneuduttiin kirjallisuuskatsauksen avulla Near Field Communication -teknologian eli NFC:n ominaisuuksiin sekä NFC-maksamiseen liittyvien mahdollisuuksien ja haasteiden erityispiirteisiin käyttäjän näkökulmasta. Tutkimustuloksina todettiin NFC-maksamisella olevan huomattava määrä kehittäjiä ja muita tukijoita takanaan, mikä edesauttaa nopeaa teknologista kehitystä. NFC:llä vaikuttaisikin olevan hyvät mahdollisuudet kilpailla muiden elektronisten maksutapojen kanssa. NFC-maksamisen helppous …
Discerning the Origins of the Amplitude Fluctuations in Dynamic Raman Nanospectroscopy
2012
International audience; We introduce a novel experimental and analytical method for discerning rare surface-enhanced Raman scattering (SERS) events observable at the nanoscale. We show that the kinetics of the Raman activity recorded on an isolated nanostructure is punctuated by intense and rare events of large amplitude and spectral variations. The fluctuations of thousands of SERS spectra were analyzed statistically in terms of power density functions, and the occurrence of the rare events was quantified by a wavenumber statistics. Our analysis enables one to extract valuable and unique spectroscopic signature of Raman variations usually hidden in time-average or space-average measurement…
Using synchrotrons and XFELs for time-resolved X-ray crystallography and solution scattering experiments on biomolecules
2015
International audience; Time-resolved structural information is key to understand the mechanism of biological processes, such as catalysis and signalling. Recent developments in X-ray sources as well as data collection and analysis methods are making routine time-resolved X-ray crystallography and solution scattering experiments a real possibility for structural biologists. Here we review the information that can be obtained from these techniques and discuss the considerations that must be taken into account when designing a time-resolved experiment.