Search results for "co2"

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…

ZrO2 Based materials as photocatalysts for 2-propanol oxidation by using UV and solar light irradiation and tests for CO2 reduction

2018

Abstract Bare ZrO2, Ce doped ZrO2 and Er doped ZrO2 samples have been prepared by a hydrothermal process and have been used as photocatalysts for 2-propanol oxidation reaction in gas solid regime. Moreover, some preliminary tests have been carried out for CO2 reduction. The samples were physico-chemically characterized and both bare and doped ZrO2 based materials resulted active for oxidation and reduction reactions by using UV and solar irradiation. The reactivity results have been correlated with the compositional, structural and morphological features of the photocatalysts.

Thermomineral waters of Greece: geochemical characterization

2020

FLUJOS DE CO2 EN ECOSISTEMAS MEDITERRÁNEOS: INFLUENCIA DE FACTORES BIÓTICOS Y ABIÓTICOS

2016

Tesis Universitat de València, Departament de Microbiologia i Ecologia, Programa de Doctorat en Biodiversitat. Desarrollada en la Estación Experimental de Zonas Áridas en [EN]Almería

Influencia del disolvente en las reacciones orgánicas

2012

La mayoría de los procesos químicos industriales, particularmente de la Química fina, se realizan en disolución. El disolvente puede tener una influencia decisiva en la eficacia de la reacción y es, por tanto, un parámetro estratégico en la planificación de una síntesis. Los disolventes orgánicos, particularmente halogenados y/o aromáticos, plantean problemas en cuanto a su toxicidad, inflamabilidad e impacto medioambiental y por ello su reemplazo por medios alternativos con un menor impacto medioambiental y que mejoren las eficiencias de las reacciones y los procesados finales es un objetivo de interés. Los fluidos supercríticos ofrecen interesantes oportunidades en este campo debido a sus…

Design of nonionic surfactants for supercritical carbon dioxide

1996

Interfacially active block copolymer amphiphiles have been synthesized and their self-assembly into micelles in supercritical carbon dioxide (CO 2 ) has been demonstrated with small-angle neutron scattering (SANS). These materials establish the design criteria for molecularly engineered surfactants that can stabilize and disperse otherwise insoluble matter into a CO 2 continuous phase. Polystyrene- b -poly(1,1-dihydroperfluorooctyl acrylate) copolymers self-assembled into polydisperse core-shell-type micelles as a result of the disparate solubility characteristics of the different block segments in CO 2 . These nonionic surfactants for CO 2 were shown by SANS to be capable of emulsifying u…

A New Evaluation of Emergency Methods for Artificial Ventilation

1968

SUMMARY The effect of artificial ventilation by the exhaled-air methods (mouth-to-nose and mouth-to-mouth) and chest-pressure-arm-lift methods (Ho-ward-Thomsen, Silvester-Brosch, Holger Nielsen) was investigated in 11 anaesthetised apnoeic volunteers. The efficiency of these methods was assessed by the changes in arterial PO2, O2 saturation, PCO2 and pH. It could be shown that the exhaled-air methods ensured normal PO2 and O2 saturation in all cases, while the ventilation by the manual methods was insufficient. Even though normal oxygenation was achieved by the manual methods in some cases, others were extremely hypoventilated, with critically low O2 tensions. pH and CO2 tensions did not ch…

A histological evaluation of the surgical margins from human oral fibrous-epithelial lesions excised with CO2 laser, Diode laser, Er:YAG laser, Nd:YA…

2018

Background We aim to evaluate the presence of histological artefacts in the surgical margins of human oral fibro-epithelial hyperplasias excised with lasers of different wavelengths, and also electrosurgical scalpel and cold scalpel. Moreover, we aim to determine if some of these instruments could impair the normal histological diagnosis of these lesions. Material and Methods We included 130 consecutive surgical samples of 80 females and 50 males (mean age of 53.82±16.55) with a histological diagnosis of an oral benign fibrous-epithelial hyperplasias. The samples were categorized into 6 groups according to the type of instrument used: CO2 laser group, diode laser group, Er:YAG laser group, …

Predicting hypoxia in cystic fibrosis patients during exposure to high altitudes

2006

Abstract Background For patients with cystic fibrosis (CF)-related partial respiratory insufficiency and reduced arterial oxygen tension at ground level, the mild hypobaric environment on commercial jet aircraft poses the risk of severe hypoxemia. Thus, physicians should be able to estimate the extent of in-flight hypoxia. Objectives To derive tools for estimating the expected drop in arterial oxygen partial pressure (paO 2 ) and oxygen saturation (saO 2 ) in young adult CF patients with mild to moderate airway obstruction during exposure to the hypobaric conditions aboard commercial aircraft and to test the predictive power of a hypobaric chamber simulation. Methods Blood gases of 12 CF pa…

Performance of EasyBreath Decathlon Snorkeling mask for delivering continuous positive airway pressure

2021

AbstractDuring the COVID-19 pandemic, the need for noninvasive respiratory support devices has dramatically increased, sometimes exceeding hospital capacity. The full-face Decathlon snorkeling mask, EasyBreath (EB mask), has been adapted to deliver continuous positive airway pressure (CPAP) as an emergency respiratory interface. We aimed to assess the performance of this modified EB mask and to test its use during different gas mixture supplies. CPAP set at 5, 10, and 15 cmH2O was delivered to 10 healthy volunteers with a high-flow system generator set at 40, 80, and 120 L min−1 and with a turbine-driven ventilator during both spontaneous and loaded (resistor) breathing. Inspiratory CO2 par…