Search results for "silica."

Nano-Silica Carriers Coated by Chloramphenicol: Synthesis, Characterization, and Grinding Trial as a Way to Improve the Release Profile

2022

Silica nanoparticles were applied as the carrier of chloramphenicol (2,2-dichloro-N-[(1R,2R)-1,3-dihydroxy-1-(4-nitrophenyl)propan-2-yl]acetamide), and were loaded in a 1% carbopol-based gel (poly(acrylic acid)), which allowed obtainment of an upgraded drug form. The samples of silica materials were obtained by means of modified Stöber synthesis, and their morphological properties were analyzed using Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) method, elemental analysis (EA), thermogravimetric analysis (TGA), analysis of the specific surface properties, X-ray diffraction study (XRD), scanning electron microscope (SEM), and dynamic light scattering (DLS) meth…

P046 Occupational exposures and gastric cancer risk in the MCC-spain case-control study

2016

Objective To explore the relationship between gastric cancer (GC) and occupational exposures. Methods A total of 382 incident GC cases and 2,846 randomly selected population controls with occupational information were included from the MCC-Spain study, a population-based multicase-control study. Occupation was coded according to the Spanish National Classification of Occupations 1994. Occupational exposures were assessed by the MatEmEsp Job Exposure Matrix. ORs and their 95% confidence intervals (CI) were estimated by unconditional logistic regression adjusting for matching variables and education. Results In men, a statistically significant increased risk of GC, was found for ‘Employed ski…

EPOXY RESIN VS BIOCERAMIC: SYSTEMATIC REVIEW WITH META-ANALYSIS

2021

Eumelanin Coating of Silica Aerogel by Supercritical Carbon Dioxide Deposition of a 5,6-Dihydroxyindole Thin Film

2018

Eumelanin integration in silica aerogel (SA) was achieved via supercritical adsorption of 5,6-dyhydroxyindole (DHI) from CO2. Notably, after the supercritical treatment, DHI evolved towards spontaneous polymerization, which resulted in uniform pigment development over the SA. The new material was characterized for its morphological and physicochemical properties, disclosing the formation of a eumelanin-like coating, as confirmed by UV&ndash

Degassing of halogens from basaltic volcanism: Insights from volcanic gas observations

2009

Abstract The currently available data set of S–Cl–F abundances in volcanic gas plumes and high-temperature fumarolic gas samples from basaltic volcanism is reviewed here in the attempt to derive constraints on the modes of halogen degassing from mafic silicate melts. Apart from large volcano-to-volcano variations, reflecting remarkable differences in volatile abundances in the source magmas, each of the explored volcanoes displays large changes of SO2/HCl and SO2/HF ratios with the style of volcanic activity, with HCl/HF staying fairly constant. Halogen abundances are low and SO2/HCl and SO2/HF are high when fresh (volatile-rich) magmas sustain degassing, as during explosive eruptions, at t…

Spectroscopic Properties of Holmium-Aluminum- Germanium Co-doped Silica Fiber

2020

We report the basic spectroscopic properties of a home-made holmium-aluminum-germanium co-doped silica fiber, designed for laser applications. We present the ground-state and excitedstate absorption spectra of the fiber along with the upconversion emission spectrum under laser action, which served for making an energy levels’ diagram of Ho3+ ion. We discuss the ways to assess the kinetics of Ho3+ 2-μm fluorescence, focusing on measuring fluorescence lifetime from 5I7 level and nonradiative decay time from 5I6 level. The simple analytical formulae, applicable for fitting of the fluorescence decay curve, are derived, which can be useful for precise modeling of holmiumdoped fiber lasers. PID20…

Photoluminescence of SiO2 under excitation by synchrotron radiation above the fundamental absorption edge

2008

Educational or emotional languages? An interactive experiment with the Lucanian flora (S-Italy)

2010

In the frame of dissemination activities for a still-in-progress work on the Sites of Community Importance (see EU Directive 92/43) of Basilicata (a region of Southern Italy), an interactive tool (IIT) for the identification of vascular plants growing there has been illustrated to two groups of people, following two different approaches: one focused on textual parts and on scientific accuracy, the other on images and on the visual comparison of different objects. The reactions were measured in terms of number of accesses to the IIT, elapsed time from the demonstration to the first individual access, and number of queries in the first week after the IIT was distributed. The most clicked opti…

Beneficiation, desilication and selective precipitation techniques for phosphorus refining from biomass derived fly ash

2018

The supply of affordable phosphorus (P), a biocritical element, is at great risk due to the utilization of limited natural phosphate minerals at an unprecedented scale. The need of phosphorus recovery to sustain the anthropogenic P-cycle was recog- nized and fly ash, a waste product from the combustion of renewable biofuels, was selected as the secondary resource. Increasing supply of fly ash in the future due to growing use of forest biofuels in energy production also contributes to its suitability for P-recovery. Fly ash comprises of silicates, oxides, carbonates, phosphates and hydroxides of the elements that potentially represent the entire periodic table. This only augments the complexity…

Mesoporous silica microparticles gated with a bulky azo derivative for the controlled release of dyes/drugs in colon.

2018

[EN] Mesoporous silica microparticles were prepared, loaded with the dye safranin O (M-Saf) or with the drug budesonide (M-Bud) and capped by the grafting of a bulky azo derivative. Cargo release from M-Saf at different pH values (mimicking those found in the gastrointestinal tract) in the absence or presence of sodium dithionite (a reducing agent mimicking azoreductase enzyme present in the colon) was tested. Negligible safranin O release was observed at pH 6.8 and 4.5, whereas a moderate delivery at pH 1.2 was noted and attributed to the hydrolysis of the urea bond that linked the azo derivative onto the external surface of the inorganic scaffold. Moreover, a marked release was observed w…