8 research outputs found
Successful fiber sensing technologies and hot topics for the near future
Inside the Photonics field Optical Fiber Sensors (OFS) are currently being used and will still be used in the future in a wide number of applications because its properties present technical advantages over traditional techniques or, sometimes, is practically the only feasible solution. In this paper, the more successful techniques will be reviewed. Then a prospective for the near future of the market and hot topics in which invest research resources will be suggested
Stable Polymorphs Crystallized Directly under Thermodynamic Control in Three-Dimensional Nanoconfinement: A Generic Methodology
Self-Assembly of Gold Nanoparticles as Colloidal Crystals Induced by Polymerization of Amphiphilic Monomers
Superparamagnetic Nanocomposites Based on the Dispersion of Oleic Acid-Stabilized Magnetite Nanoparticles in a Diglycidylether of Bisphenol A-Based Epoxy Matrix: Magnetic Hyperthermia and Shape Memory
Superparamagnetic nanocomposites were obtained by dispersion
of
oleic acid (OA)-coated magnetite NPs in an epoxy system based on diglycidylether
of bisphenol A (DGEBA) modified with OA. Dispersion of conventional
oleic acid-stabilized magnetite NPs in a typical epoxy matrix is not
possible due to the dissimilar chemical structures of the organic
coating and the reactive solvent. However, by modification of a DGEBA-based
epoxy with 20 wt % OA, we obtained a suitable reactive solvent to
disperse up to at least 8 wt % of OA-stabilized magnetite NPs. A tertiary
amine was used to catalyze the epoxy–acid reaction and initiate
the homopolymerization of the epoxy excess. Both reactions occurred
practically in series, first the epoxy–acid and then the epoxy
homopolymerization. It was necessary to complete the first reaction
to attain a very good dispersion of magnetite NPs in the reactive
solvent previous to the occurrence of the final reaction. Magnetization
curves and TEM images revealed a uniform dispersion of individual
nanoparticles in the cross-linked epoxy. A sample containing 8 wt
% OA-coated magnetite NPs exhibited a temperature increase of 25 °C
at its surface when exposed to an alternating magnetic field. The
temperature increase was enough to induce the shape memory effect
of the nanocomposite
Structure-Directing and High-Efficiency Photocatalytic Hydrogen Production by Ag Clusters
H<sub>2</sub> production by water splitting is hindered mainly
by the lack of low-cost and efficient photocatalysts. Here we show
that sub-nanometric silver clusters can catalyze the anisotropic growth
of gold nanostructures by preferential adsorption at certain crystal
planes of Au seeds, with the result that the final nanostructure can
be tuned via the cluster/seed ratio. Such semiconducting Ag clusters
are extremely stable and retain their electronic structure even after
adsorption at the tips of Au nanorods, enabling various photocatalytic
experiments, such as oxygen evolution from basic solutions. In the
absence of electron scavengers, UV irradiation generates photoelectrons,
which are stored within the nanorods, increasing their Au Fermi level
up to the redox pinning limit at 0 V (RHE), where hydrogen evolution
occurs with an estimated high efficiency of 10%. This illustrates
the considerable potential of very small zerovalent, nonmetallic clusters
as novel atomic-level photocatalysts
Transformation of Gold Nanorods in Liquid Media Induced by nIR, Visible, and UV Laser Irradiation
Gold
nanorods (GNRs) were initially prepared with three different
aspect ratios (2.5, 2.9, and 3.8) via a seed-mediated chemical route,
using cetyltrimethylammonium bromide (CTAB) as the organic surfactant.
These rods were then irradiated under continuous-wave (λ = 1064
nm) and pulsed (λ = 1064, 532, 355 nm) emission modes using
Nd:YVO<sub>4</sub> and Nd:YAG lasers, respectively. The photostability
and behavior of the Au nanorods under these laser irradiation conditions
were studied using UV–vis–nIR spectroscopy and electron
microscopy. Photofragmentation and melting mechanisms were provoked
as a function of laser irradiation parameters (emission mode and wavelength)
and caused the GNRs to undergo considerable morphological changes.
Important differences were observed between the wavelengths used for
irradiation, indicating significantly different nanorod breakdown
mechanisms
Leapfrogging Ostwald’s Rule of Stages: Crystallization of Stable γ-Glycine Directly from Microemulsions
Safety of hospital discharge before return of bowel function after elective colorectal surgery
Background Ileus is common after colorectal surgery and is associated with an increased risk of postoperative complications. Identifying features of normal bowel recovery and the appropriateness for hospital discharge is challenging. This study explored the safety of hospital discharge before the return of bowel function. Methods A prospective, multicentre cohort study was undertaken across an international collaborative network. Adult patients undergoing elective colorectal resection between January and April 2018 were included. The main outcome of interest was readmission to hospital within 30 days of surgery. The impact of discharge timing according to the return of bowel function was explored using multivariable regression analysis. Other outcomes were postoperative complications within 30 days of surgery, measured using the Clavien-Dindo classification system. Results A total of 3288 patients were included in the analysis, of whom 301 (9 center dot 2 per cent) were discharged before the return of bowel function. The median duration of hospital stay for patients discharged before and after return of bowel function was 5 (i.q.r. 4-7) and 7 (6-8) days respectively (P < 0 center dot 001). There were no significant differences in rates of readmission between these groups (6 center dot 6 versus 8 center dot 0 per cent; P = 0 center dot 499), and this remained the case after multivariable adjustment for baseline differences (odds ratio 0 center dot 90, 95 per cent c.i. 0 center dot 55 to 1 center dot 46; P = 0 center dot 659). Rates of postoperative complications were also similar in those discharged before versus after return of bowel function (minor: 34 center dot 7 versus 39 center dot 5 per cent; major 3 center dot 3 versus 3 center dot 4 per cent; P = 0 center dot 110). Conclusion Discharge before return of bowel function after elective colorectal surgery appears to be safe in appropriately selected patients