Search results for " laser"
showing 10 items of 1455 documents
Effects of a low-power He-Ne laser on the healing of experimental colon anastomoses: our experience
1992
Despite technical advances, the incidence of anastomotic leaks in elective colorectal surgery remains around 14%. Recent studies suggest that the use of low-energy lasers may enhance wound healing in different tissues in a selective, nondestructive manner. Based on these findings we have attempted to provide experimental background on the effects of a He-Ne laser during the early stages of healing in 155 colonic anastomoses performed on rats. The irradiation (external or endoscopical) ofthe anastomoses by repeated doses below 4 J/cm 2 suggest (1) the laser-induced enhancement of anastomotic healing can be obtained in both healthy colons or in situations in which anastomotic breakdown is mor…
Comparing the effect of diode laser against acyclovir cream for the treatment of herpes labialis
2017
Background Recently alternative therapies such as the use of diode laser therapy have been introduced for recurrent herpes labial infection. The aim of this study was to evaluate the effectiveness of diode laser for treatment of recurrent herpes labialis. Material and Methods This was single-blind randomized clinical trial to evaluate the efficacy of diode laser for the treatment of recurrent herpes labial. In total, 60 patients whit recurrent herpes simplex labialis were selected and randomly divided in to three groups. 20 patients received treatment whit diode laser (at a wavelength of 870 nm, energy density 4.5 j/cm2), 20 patients were treated with acyclovir cream 5%, 20 patients receive…
Low-level laser therapy for treatment of neurosensory disorders after orthognathic surgery : a systematic review of randomized clinical trials
2017
Background Low-level laser has been widely used in Dentistry and many studies have focused on its application in oral surgeries. This study was conducted with the aim of searching for scientific evidence concerning the effectiveness of laser to reduce pain or paresthesia related to orthognathic surgery. Material and methods An electronic search was performed in PubMed, Scopus, Science Direct, LILACS, SciELO, CENTRAL, Google Scholar, OpenGrey, and ClinicalTrials.gov, up to November 2016, with no restrictions on language or year of publication. Additionally, a hand search of the reference list of the selected studies was carried out. The PICOS strategy was used to define the eligibility crite…
Heat shock protein expression and anti-heat shock protein reactivity in renal cell carcinoma.
2002
Heat shock proteins (HSP) are families of highly conserved proteins which are induced in cells and tissues upon exposure to extreme conditions causing acute or chronic stress. They exhibit distinct functions and have been implicated in the pathogenesis of a number of diseases, including cancer. A causal relationship between HSP expression and immunogenicity has been demonstrated in murine and human tumors and is also associated with the immune response. In order to investigate the correlation of HSP expression and their immunogenic potential in renal cell carcinoma (RCC), we here analyzed (i) the protein expression profile of various members of the HSP family in untreated and interferon (IF…
Bright Visible Luminescence in Silica Nanoparticles
2011
International audience; We demonstrate that a porous film of silica nanoparticles emits a bright visible luminescence associated with defects stabilized by oxygen chemisorption at oxygen deficient center sites. Time-resolved spectra excited by a tunable laser allow us to distinguish the luminescence at 1.99 eV, characteristic of the nonbridging oxygen hole center (NBOHC) (Si-O)3 Si-O*, and a fast and a slow emission: the first (lifetime τ ≈ 25 ns) is peaked at 2.27 eV with an excitation spectrum centered at 5.5 eV; the second (τ ≈ 7.5 μs) is peaked at 2.41 eV and is excited around 3.2 and 5.2 eV. Reaction in an air atmosphere leads to the disappearance of the NBOHC luminescence and of the …
Novel non-destructive inspection techniques for laser powder deposition inspection
2013
A novel non-destructive testing (NDT) techniques for inspection of parts and components manufactured by Additive Manufacturing Processes (AMP), in particular Laser Metal Deposition (LMD), has been developed. LMD is a technology that has been maturing over the last 20 years and has found application in repair, coatings, hybrid build and 3D near net shape manufacture of small intricate parts that can be used in aero and automobile engines to improve efficiency. Currently this technology cannot be used to supply some of these parts because absence of flaws, which might be left in the component during manufacture, cannot be guaranteed. Today, quality is assessed by sample destructive testing, w…
Phase-delayed laser diode array allows ultrasonic guided wave mode selection and tuning
2013
Selecting and tuning modes are useful in ultrasonic guided wave non-destructive testing (NDT) since certain modes at various center frequencies are sensitive to specific types of defects. Ideally one should be able to select both the mode and the center frequency of the launched waves. We demonstrated that an affordable laser diode array can selectively launch either the S0 or A0 ultrasonic wave mode at a chosen center frequency into a polymer plate. A fiber-coupled diode array (4 elements) illuminated a 2 mm thick acrylic plate. A predetermined time delay matching the selected mode and frequency was employed between the output of the elements. The generated ultrasound was detected by a 215…
Optical Absorption of Excimer Laser‐Induced Dichlorine Monoxide in Silica Glass and Excitation of Singlet Oxygen Luminescence by Energy Transfer from…
2021
An optical absorption (OA) band of interstitial dichlorine monoxide molecules with peak at 4.7 eV and halfwidth 0.94 eV is identified in F2 laser - irradiated (photon energy=7.9 eV) synthetic silica glass bearing both interstitial O2 and Cl2 molecules. Alongside with intrinsic defects, this OA band can contribute to solarization of silica glasses produced from SiCl4. While the formation of ClClO is confirmed by its Raman signature, its structural isomer ClOCl may also contribute to this induced OA band. Thermal destruction of this band between 300C and 400C almost completely restores the pre-irradiation concentration of interstitial Cl2. An additional weak OA band at 3.5 eV is tentatively a…
Internal conversion from excited electronic states of 229Th ions
2017
The process of internal conversion from excited electronic states is investigated theoretically for the case of the vacuum-ultraviolet nuclear transition of 229 Th . Due to the very low transition energy, the 229 Th nucleus offers the unique possibility to open the otherwise forbidden internal conversion nuclear decay channel for thorium ions via optical laser excitation of the electronic shell. We show that this feature can be exploited to investigate the isomeric state properties via observation of internal conversion from excited electronic configurations of Th + and Th 2 + ions. A possible experimental realization of the proposed scenario at the nuclear laser spectroscopy facility IGISO…
La Chapelle des Dames un splendide exemple du baroque italien
2017
Résumé Un des sujets les plus brûlants de la géomatique de ce début du XXIe siècle est la recherche des techniques les plus efficaces pour numériser et restituer les édifices modernes et historiques. Les premiers font l’objets de relevés pour constituer une maquette de type BIM, les seconds plus dans le cadre d’études académiques ou de documents de base pour des travaux de restoration. Le principal sujet de débat actuel peut se résumer en une phrase : « quelle technique pour quel relevé ? ». En effet, si d’un côté les relevés laser permettent de constituer des nuages de points extrêmement riches et détaillés (Costantino, 2013), il est ensuite souvent délicat de gérer correctement une telle …