Search results for " Laser"

2018

Abstract Purpose To report on a case of recurrence of paraproteinemic keratopathy (PPK) associated with monoclonal gammopathy after bilateral penetrating keratoplasty. Observations Penetrating keratoplasty was performed on both eyes of a 45-year-old man due to bilateral progressive corneal stromal clouding. Recurrence of the corneal stromal opacities accompanied by a decrease in visual acuity was observed on slit-lamp examination already two years after penetrating keratoplasty. Confocal laser scanning microscopy (CLSM) of the corneal grafts performed three years after penetrating keratoplasty showed bilateral morphological changes identical to that found in the patient's corneas prior to p…

Confocal scanning laser ophthalmoscopy versus modified conventional fundus camera for fundus autofluorescence.

2016

Fundus autofluorescence (FAF) is a noninvasive imaging method to detect fundus endogenous fluorophores, mainly lipofuscin located in the retinal pigment epithelium (RPE). The FAF provides information about lipofuscin distribution and RPE health, and consequently an increased accumulation of lipofuscin has been correlated with ageing and development of certain retinal conditions. Areas covered: An exhaustive literature search in MEDLINE (via OVID) and PUBMED for articles related to ocular FAF in retinal diseases and different devices used for acquiring FAF imaging was conducted. Expert commentary: This review aims to show an overview about autofluorescence in the RPE and the main devices use…

The effects of fractional CO2 laser, Nano-hydroxyapatite and MI paste on mechanical properties of bovine enamel after bleaching

2017

Background This study investigated the effect of post bleaching treatments to the change of enamel elastic modulus and microhardness after dental bleaching in- vitro. Material and Methods Fifty bovine incisor slab were randomly assigned into five groups (n=10). The samples were bleached for three times; 20 minutes each time, by 40% hydrogen peroxide. Next it was applied fractional CO2 laser for two minutes, Nano- hydroxy apatite (N-HA) and MI-paste for 7 days and 2 minutes per day. The sound enamel and bleached teeth without post treatment remained as control groups. The elastic modulus and microhardness were measured at three times; 24 hours, 1 and 2 months. Data were statistically analyze…

Offline commissioning of a new gas cell for the MARA Low-Energy Branch

2023

Results of offline commissioning tests for a new dedicated gas cell for the Mass Analysing Recoil Apparatus (MARA) Low-Energy Branch are reported. Evacuation time, ion survival and transport efficiency in helium buffer gas were characterized with a radioactive 223Ra 𝛼-recoil source. Suppression of the ion signal, originating from non-neutralized species in the gas cell, was explored with 219Rn ions, the daughter recoil of 223Ra, as a function of voltage applied to one of the ion-collector electrodes. Two-step laser resonance ionization of stable tin isotopes produced inside the gas cell from a heated bronze filament was demonstrated, and broadening of the atomic resonances in argon buffer …

2D size, position and shape definition of defects by B-scan image analysis

2015

The non-destructive evaluation of defects by automatic procedures is of great importance for structural components. Thanks to the developments of the non-contact ultrasonic techniques, the automation of the inspections is gaining a progressively important role. In this work, an automatic inspection technique for the evaluation of defects by the analysis of B-scan images obtained by a laser ultrasonic system is presented. The data are extracted directly from a B-scan map obtained for a panel with internal defects, and are used to build an image of the cross section of the panel. The proposed automatic procedure allows the definition of size, position and shape of defects in panels of known t…

La Cappella Palatina di Palermo: Misura, Interpretazione, Rappresentazione

2012

Lo studio che segue è incentrato sull'analisi delle vicende costruttive della Cappella Palatina nel Palazzo Reale di Palermo, costruita per volontà di Ruggero II nella prima metà del XII secolo. La peculiarità della Cappella è quella di aver mantenuto pressoché inalterato i caratteri spaziali dell’interno attraverso i secoli; tale peculiarità ha fatto si che la Cappella sia stata oggetto di studi molto approfonditi condotti da storici dell’arte a partire dalla del XIX secolo fino ai nostri giorni. Lo studio intende porsi come contributo alla conoscenza della Cappella, alla interpretazione di alcune questioni rimaste irrisolte, come stimolo ausiliare per successivi studi, attraverso gli stru…

GEOMATIC TECHNIQUES FOR THE COLONNADE STRUCTURAL ANALYSIS OF THE HISTORICAL “ CHIARAMONTE STERI” BUILDING

2019

The monitoring of building structures has an increasingly important role in the engineering field, above all because they are concerned with the impact that such structures have in the area where they were built. Often, when walking through the old town centres, we realize just how obsolete and dangerous some buildings (even historic-cultural ones) are. The interest of some local governments in this problem has led, in the last few years, to the study and the trying out of measuring and monitoring methods which, quickly and at low cost, allow to define the extent of the deformation and the degrade in an accurate and reliable way. The Courtyard of “Palazzo Steri - Chiaramonte” is composed of…

Porous 3D Printed Scavenger Filters for Selective Recovery of Precious Metals from Electronic Waste

2018

Selective laser sintering (SLS) 3D printing is used to fabricate highly macroporous ion scavenger filters for recovery of Pd and Pt from electronic waste. The scavengers are printed by using a mixture of polypropylene with 10 wt% of type‐1 anion exchange resin. Porosities and the flow‐through properties of the filters are controlled by adjusting the SLS printing parameters. The cylinder‐shaped filters are used in selective recovery of Pd and Pt from acidic leachate of electronic waste simply by passing the solution through the object. Under such conditions, the scavenger filters are able to capture Pd and Pt as anionic complexes with high efficiency from a solution containing mixture of dif…

3D Printed Palladium Catalyst for Suzuki-Miyaura Cross-coupling Reactions

2020

Selective laser sintering (SLS) 3d printing was utilized to manufacture a solid catalyst for Suzuki-Miyaura cross-coupling reactions from polypropylene as a base material and palladium nanoparticles on silica (SilicaCat Pd(0)R815-100 by SiliCycle) as the catalytically active additive. The 3d printed catalyst showed similar activity to that of the pristine powdery commercial catalyst, but with improved practical recoverability and reduced leaching of palladium into solution. Recycling of the printed catalyst led to increase of the induction period of the reactions, attributed to the pseudo-homogeneous catalysis. The reaction is initiated by oxidative addition of aryl iodide to palladium nano…

Caracterización de protones acelerados por láser y estudio de aplicaciones médicas

2017

El desarrollo de técnicas de amplificación láser durante las últimas décadas [1] ha derivado en una tecnología capaz de generar pulsos ultracortos, decenas de femtosegundo, y ultraintensos, en el orden del terawatio-petawatio. Estos pulsos pueden ser utilizados como vehículo para la aceleración de partículas hasta energías multi-MeV [2]. Esto ha generado un gran interés de la comunidad científica por la posibilidad de utilizar esta tecnología, que podría tener virtudes frente a los mecanismos de aceleración convencionales, además de ser un terreno inexplorado. El objetivo principal es el diseño de un experimento, detectores de partículas, y todos los periféricos necesarios para demostrar la…