ABSTRACT
Gold nanoparticle electrodeposition on a modified HOPG surface with a monolayer organic film based on aryl diazonium chemistry has been studied. This organic monolayer is electrochemically grown with the use of 2,2-diphenyl-1-picrylhydrazyl (DPPH), a radical scavenger. The electrodeposition of gold on this modified surface is highly favored resulting in an AuNP surface density comparable to that found on glassy carbon. AuNPs grow only in the areas covered by the organic monolayer leaving free clean HOPG zones. A progressive mechanism for the nucleation and growth is followed giving hemispherical AuNPs, homogeneously distributed on the surface and their sizes can be well controlled by the applied electrodeposition potential. By using AFM, C-AFM and electrochemical measurements with the aid of two redox probes, namely Fe(CN)6(4-)/Fe(CN)6(3-) and dopamine, relevant results about the electrochemical modified surface as well as the gold nanoparticles electrodeposited on them are obtained.
ABSTRACT
OBJECTIVE: Epidemiological evidence suggests an association between psychological factors and functional dyspepsia (FD). Yet few randomized controlled trials (RCTs) of psychological interventions have been conducted for FD. We conducted an RCT to evaluate the efficacy of psychotherapy among chronic FD. METHODS: One hundred fifty-eight consecutive patients with FD were randomized to medical therapy plus psychotherapy consisted in 8 group and 2 individual sessions focused on teaching techniques for coping with FD (intensive treatment (IT); n=76) or medical therapy alone (conventional treatment (CT); n=82). Patients completed validated self-reported questionnaires before and after the 10-week treatment and 6 months later. Linear mixed-effects models were used, in intention-to-treat analysis. RESULTS: At the end of treatment period, statistically significant improvements were observed for IT compared with CT for dyspepsia-related quality of life (DRQoL). DRQoL mean changes of 6.09 and 3.54 were obtained in IT and CT patients, respectively (p=<0.0001); and SS mean changes of 11.55 and 4.57 were obtained in IT and CT patients, respectively (p=0.0013). Those improvements, measured by minimum clinically important difference (MCID), were clinically significant (DRQoL: 77% of the IT patients exceeded the MCID vs. the 45% of the CT; SS: 75% vs. 48%). Six months after treatment, those statistically significant improvements persisted for DRQoL (p=0.0067) and for SS (p=0.0405). Clinical improvements persisted for SS (63% vs. 41%). CONCLUSIONS: These findings suggest that adding psychotherapy to standard medical therapy improves short-term outcomes in patients with FD and may have long-term effects as well. The cost-effectiveness of intensive therapy needs to be evaluated. Registration number and name of trial registry: NCT01802710.
Subject(s)
Adaptation, Psychological , Dyspepsia/psychology , Dyspepsia/therapy , Psychotherapy , Quality of Life , Combined Modality Therapy/methods , Dyspepsia/physiopathology , Female , Humans , Male , Middle Aged , Psychotherapy/methods , Psychotherapy, Group , Self Report , Severity of Illness Index , Surveys and Questionnaires , Treatment OutcomeABSTRACT
Reductive electrodesorption has been used to produce "naked" gold nanoparticles (AuNPs) 3 nm in size on HOPG from different thiolate-capped AuNPs. The clean AuNPs transform the electrocatalytic inert HOPG into an active surface for hydrogen peroxide electroreduction, causing a lowering of the cathodic overpotential of 0.25 V with respect to the Au(111) surface. Compared to the plain gold substrates, the nanostructures promote only a slight increase in the hydrogen evolution reaction. In a second modification step a â¼1 nm thick melanin-iron coating is electrochemically formed around the AuNPs. This ultrathin melanin-iron coating largely improves the catalytic activity of the bare AuNPs for both hydrogen peroxide electroreduction and hydrogen evolution reaction. This strategy, which integrates electrochemistry and nanotechnology, can be applied to the preparation of efficient "naked" AuNPs and organic-iron capped AuNPs catalysts.
