Water Decontamination from Cr(VI) by Transparent Silica Xerogel Monolith.

Cr(VI) is highly soluble and mobile in water solution and extremely toxic. In order to obtain a specific material with adsorption properties towards Cr(VI), and that can be used in environmental remediation of water contaminated with Cr(VI), one-step sol-gel technique, at low temperature (50 °C), has been optimized to prepare transparent silica-based xerogel monolith by using tetraethyl orthosilicate as precursor. The obtained xerogel, with disk shape, was fully characterized by Raman, BET, FE-SEM and XRD analysis. The results indicated that the material showed silica amorphous phase and high porosity. The study of the adsorption properties towards different concentrations of Cr(VI), in the form of HCrO4- in acidic condition, showed prominent results. The absorption kinetics were evaluated by studying different models, the final result showing that the absorption of Cr(VI) occurred through intra-particle diffusion process, following two steps, and that the absorption equilibrium is regulated by Freundlich isotherm model. The material can be restored by reducing the hazardous Cr(VI) to Cr(III), a less toxic form of chromium, by 1,5-diphenylcarbazide, and with successive treatment in acidic water.

Enhancing the Amyloid-ß Anti-Aggregation Properties of Curcumin via Arene-Ruthenium(II) Derivatization.

Alzheimer's disease (AD) is a fatal neurodegenerative disorder associated with severe dementia, progressive cognitive decline, and irreversible memory loss. Although its etiopathogenesis is still unclear, the aggregation of amyloid-ß (Aß) peptides into supramolecular structures and their accumulation in the central nervous system play a critical role in the onset and progression of the disease. On such a premise, the inhibition of the early stages of Aß aggregation is a potential prevention strategy for the treatment of AD. Since several natural occurring compounds, as well as metal-based molecules, showed promising inhibitory activities toward Aß aggregation, we herein characterized the interaction of an organoruthenium derivative of curcumin with Aß(1-40) and Aß(1-42) peptides, and we evaluated its ability to inhibit the oligomerization/fibrillogenesis processes by combining in silico and in vitro methods. In general, besides being less toxic to neuronal cells, the derivative preserved the amyloid binding ability of the parent compound in terms of equilibrium dissociation constants but (most notably) was more effective both in retarding the formation and limiting the size of amyloid aggregates by virtue of a higher hindering effect on the amyloid-amyloid elongation surface. Additionally, the complex protected neuronal cells from amyloid toxicity.

Silver Nanoparticle-Based Sensor for the Selective Detection of Nickel Ions.

Silver nanoparticles (AgNPs) can be used as a surface plasmon resonance (SPR) colorimetric sensor; the correlation between the SPR phenomenon and the aggregation state of nanoparticle allows the real-time detection of a target molecule. Surface functionalization of NPs with proper molecular baits is often performed to establish the selectivity of the sensor. This work reports on the synthesis of AgNPs under reducing conditions and on the functionalization thereof with mercaptoundecanoic acid (11-MUA). UV-VIS Spectroscopy confirmed the formation of AgNPs, eliciting a surface plasmon absorption band (SPAB) at 393 nm that shifted to 417 nm upon surface coating. Dynamic light scattering was used to investigate the surface coatings; moreover, pelleted AgNPs@11MUA nanoparticles were characterized by scanning electron microscopy (SEM), energy dispersive X-ray analyzers (EDX), and infrared spectroscopy to corroborate the presence of 11MUA on the surface. Most interestingly, the resulting AgNPs@11MUA selectively detected micromolar levels of Ni2+, also in the presence of other cations such as Mn2+, Co2+, Cd2+, Cu2+, Zn2+, Fe2+, Hg2+, Pb2+, and Cr3+.

HPLC-DAD-ESI/MS identification of light harvesting and light screening pigments in the lake sediments at Edmonson Point.

The composition of sedimentary pigments in the Antarctic lake at Edmonson Point has been investigated and compared with the aim to provide a useful analytical method for pigments separation and identification, providing reference data for future assessment of possible changes in environmental conditions. Reversed phase high performance liquid chromatography (HPLC) with electrospray-mass spectrometry (ESI-MS) detection and diode array detection (DAD) has been used to identify light screening and light harvesting pigments. The results are discussed in terms of local environmental conditions.