Functionalized platinum nanoparticles with surface charge trigged by pH: synthesis, characterization and stability studies

In this work, the synthesis and characterization of functionalized platinum nanoparticles (PtNPs) have been investigated. PtNPs were obtained by a wet redox procedure using 2-diethylaminoethanethiol hydrochloride (DEA) as capping agent. By varying the Pt/thiol molar ratio, monodispersed and stable particles with diameters in the range of 3-40 nm were isolated. The amino functionality allows neutral particles to be obtained in basic water solution and positive charged nanoparticles in neutral or acidic water solution (pH 7-2), as confirmed by DLS and ζ-potential measurements. FTIR spectroscopy, FE-SEM, DLS and ζ-potential measurements confirmed the size and showed long term water stability (up to three months) of the colloidal system

Spatial properties of π−π\pi-\pi conjugated network in semicrystalline polymer thin films studied by intensity x-ray cross-correlation functions

We present results of x-ray study of spatial properties of $\pi-\pi$ conjugated networks in polymer thin films. We applied the x-ray cross-correlation analysis to x-ray scattering data from blends of poly(3-hexylthiophene) (P3HT) and gold nanoparticles. The Fourier spectra of the intensity cross-correlation functions for different films contain non-zero components of orders $n=2,4$ and $6$ measuring the degree of structural order in the system.Comment: 6 pages, 2 figures, Proceedings ICXOM22 Conference, 2-6 September 2013, Hamburg, German

Substrate–Support Interactions Mediate Hydrogenation of Phenolic Compounds by Pd/CeO2 Nanorods

Ceria-supported palladium (Pd/CeO2) has spawned significant attention in recent years due to its ability to catalyze selective hydrogenation of phenolic compounds to cyclohexanones and cyclohexanols at a mild temperature and pressure. However, the mechanistic basis by which ceria enhances catalytic conversion is still unclear. Here, we use the increase in the 13C transverse relaxation rate upon the addition of nanoparticles (NPs) (13C ΔR2) to investigate the adsorption of phenolic compounds on the surface of the Pd/CeO2 catalyst by solution NMR. We show that hydroxyphenols adsorb on the support more efficiently than underivatized phenol and methoxyphenols and that phenol derivatives with an oxygen atom at position 2 (i.e., 2-hydroxyphenol and 2-methoxyphenol) form very stable interactions with the Pd site of Pd/CeO2. An analysis of the kinetics of hydrogenation revealed that catalytic conversion is linearly correlated with the ability of the substrate to form interactions with the CeO2 support and is inhibited by the formation of stable substrate–Pd adducts. Our data suggest that CeO2–substrate interactions mediate phenol hydrogenation more efficiently than Pd–substrate interactions and explain the exceptional catalytic performance reported for Pd/CeO2

Mechanistic Insight into Nanoparticle Surface Adsorption by Solution NMR Spectroscopy in an Aqueous Gel

Engineering nanoparticle (NP) functions at the molecular level requires a detailed understanding of the dynamic processes occurring at the NP surface. Herein we show that a combination of dark‐state exchange saturation transfer (DEST) and relaxation dispersion (RD) NMR experiments on gel‐stabilized NP samples enables the accurate determination of the kinetics and thermodynamics of adsorption. We used the former approach to describe the interaction of cholic acid (CA) and phenol (PhOH) with ceria NPs with a diameter of approximately 200 nm. Whereas CA formed weak interactions with the NPs, PhOH was tightly bound to the NP surface. Interestingly, we found that the adsorption of PhOH proceeds via an intermediate, weakly bound state in which the small molecule has residual degrees of rotational diffusion. We believe the use of aqueous gels for stabilizing NP samples will increase the applicability of solution NMR methods to the characterization of nanomaterials

Distress influence in fibromyalgia

Objective: Fibromyalgia syndrome (FM) is a controversial chronic painful syndrome. Although the aetiology is unknown, FM is frequently correlated with stressors events. Recent studies highlighted the frequent comorbidity with anxiety and depression and a close relationship between stress and pain. Methods: We evaluated the relevance of stressors events in 23 patients with FM (mean age: 45.7±7.4 SD), compared with 18 healthy controls (mean age: 41.7±6.4 SD) and 17 patients with dysfunctional syndrome (mean age 40.8±6.1). We performed the italian validated rapid assessment of the stress test (VRS) for the assessment of stress. Furthermore, we evaluated the psychological history for a semi-quantitative assessment (IVAS) of the 49 stress-generating events listed in 1994’s DSM-IV. Results: The group of “healthy” subjects showed stress values at VRS test (mean: 7.00±4.65 SD) significantly lower (p=0.0001) than the patients with “dysfunctional syndrome“ (mean 14.82±7.69 SD) and those with FM (mean 20.04±9.90 SD). The IVAS test, showed higher values in FM subgroup than healthy (p=0.0001) and dysfunctional syndromes (p=0,007). Also, the patients with FM showed a greater gravity to attribute to single stressors events (p=0.02). Conclusions: Our results emphasize the importance of the perceived stress among the patients with FM, and support the hypothesis that FM could be due to a psycho-neuro-endocrinal response to several stressors events in patients with genetical hyperresponsiveness to stress

Distress influence in fibromyalgia

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