RESUMEN
Chemically synthesized metal nanoparticles (MNPs) have been widely used as surface-enhanced Raman spectroscopy (SERS) substrates for monitoring catalytic reactions. In some applications, however, the SERS MNPs, besides being plasmonically active, can also be catalytically active and result in Raman signals from undesired side products. The MNPs are typically insulated with a thin (â¼3 nm), in principle pin-hole-free shell to prevent this. This approach, which is known as shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS), offers many advantages, such as better thermal and chemical stability of the plasmonic nanoparticle. However, having both a high enhancement factor and ensuring that the shell is pin-hole-free is challenging because there is a trade-off between the two when considering the shell thickness. So far in the literature, shell insulation has been successfully applied only to chemically synthesized MNPs. In this work, we alternatively study different combinations of chemical synthesis (bottom-up) and lithographic (top-down) routes to obtain shell-isolated plasmonic nanostructures that offer chemical sensing capabilities. The three approaches we study in this work include (1) chemically synthesized MNPs + chemical shell, (2) lithographic substrate + chemical shell, and (3) lithographic substrate + atomic layer deposition (ALD) shell. We find that ALD allows us to fabricate controllable and reproducible pin-hole-free shells. We showcase the ability to fabricate lithographic SHINER substrates which report an enhancement factor of 7.5 × 103 ± 17% for our gold nanodot substrates coated with a 2.8 nm aluminium oxide shell. Lastly, by introducing a gold etchant solution to our fabricated SHINER substrate, we verified that the shells fabricated with ALD are truly pin-hole-free.
RESUMEN
The electrochemical synthesis of α ${\alpha }$ -amino acids at room temperature and pressure is a sustainable alternative to conventional methods like microbial fermentation and Strecker synthesis. A custom-built zero-gap flow electrolyzer was used to study the electrosynthesis of alanine via the electrocatalytic reductive amination (ERA) of the corresponding biomass-derivable α ${\alpha }$ -keto acid precursor - pyruvic acid (PA), and hydroxylamine (NH2OH) at very low pH. Non-toxic, abundant, and easy to prepare TiO2/Ti electrocatalysts were utilized as the cathode. Three TiO2/Ti felt electrodes with different oxide thicknesses were prepared and their characterization results were correlated with their respective electrochemical performance in terms of Faradaic efficiency η ${\eta }$ , and partial current density j â¾ ${\left|\overline{j}\right|}$ . Cyclic voltammetry indicated a different electrocatalytic reduction process on hydrothermally treated electrodes, compared to thermally oxidized ones. Hydrothermally treated electrodes were also found to have the thickest porous anatase layer and achieved 50-75 % alanine conversion efficiencies. Optimization showed that the cell potential, reactant flow rate and the PA: NH2OH ratio were crucial parameters in determining the conversion efficiency. η ${\eta }$ and j â¾ ${\left|\overline{j}\right|}$ were found to significantly decrease when an excess of is used and, an optimal alanine η ${\eta }$ of 75 % was achieved at 2.0â V applied cell potential and 10â mL/h reactant flow rate.
RESUMEN
BACKGROUND: Occupational Health Service (OHS) is a service that should support employers and employees with their work environment. Previous research indicates the need for deeper knowledge about the effect of workplace interventions with a focus on planning, organizing and designing the workplace to improve work conditions in hospital settings. OBJECTIVE: The aim was to evaluate the outcomes, workplace interventions and intervention strategies in hospital settings. METHODS: A systematic literature review was conducted. CINAHL, MEDLINE, PsycInfo, Scopus, and Web of Science Core Collection were searched in September 2021. The Mixed Methods Appraisal Tool was used to evaluate the quality of the included studies. Study results are presented through a narrative synthesis. A protocol for this study was registered on the Open Science Framework. RESULTS: Twenty-six studies, published between 2010 and 2021, were included. These included randomized controlled trials (RCTs), non-RCTs, and mixed methods reports with moderate to good quality. The results support the use of workplace interventions to improve work conditions, health, and well-being in hospital settings. Combinations of different interventions, tailored to the specific organization, were used. Important intervention strategies commonly used in the start-up, evaluation, and intervention of successful workplace interventions, were identified. Using a pragmatist complexity approach in workplace interventions can improve outcomes by providing clear intervention strategies and combinations of tailored interventions, related to context specific problems. CONCLUSION: OHS support in workplace interventions with clear intervention strategies will contribute to improve work conditions, health and well-being in hospital settings.