OBJECTIVES The capacity to properly address the worldwide incidence of infectious diseases lies in the ability to detect, prevent and effectively treat these infections. Therefore, identifying and analysing inhibitory agents are worthwhile endeavours in an era when few new classes of effective antimicrobials have been developed. The use of geological nanomaterials to heal skin infections has be...

Palygorskite, a fibrous clay mineral, is being used as a substitute for asbestos in some applications. Nine specimens obtained from different geological locales were studied for mineral purity, elemental composition, fibre size distribution, and surface binding characteristics. The membranolytic activity of each was determined using a human erythrocyte model. The membranolytic behaviour and sur...

In this study, ZnO/SiO2-clay heterostructures were successfully synthesized by a facile two-step process applied to two types of clays: montmorillonite layered silicate and sepiolite microfibrous clay mineral. In the first step, intermediate silica-organoclay hybrid heterostructures were prepared following a colloidal route based on the controlled hydrolysis of tetramethoxysilane in the presenc...

Computer simulations are used to calculate the elastic properties of model cemented sandstones composed of two or more mineral phases. Two idealized models are considered – a grain-overlap clay/quartz mix and a pore-lining clay/quartz mix. Unlike experimental data, the numerical data exhibit little noise yet cover a wide range of quartz/cement ratios and porosities. The results of the computati...

We have studied optical properties (in optic and petrographic microscopy) of mineral particles (diameter > 1 μm) deposited on the surface of a small (≈ 1.4 mm height, 610 μm wide) sticky tape triangle corresponding to the Face area of the Turin Shroud (TS). All these particles were studied by scanning electronic microscopy (SEM) and their elemental compositions were analysed by X-ray microfluor...

Natural clays have been used to heal skin infections since the earliest recorded history. Recently our attention was drawn to a clinical use of French green clay (rich in Fe-smectite) for healing Buruli ulcer, a necrotizing fasciitis ('flesh-eating' infection) caused by Mycobacterium ulcerans. These clays and others like them are interesting as they may reveal an antibacterial mechanism that co...

Atmospheric nitrated polycyclic aromatic hydrocarbons (NPAHs), which have been shown to have adverse health effects such as carcinogenicity, are formed in part through nitration reactions of their parent polycyclic aromatic hydrocarbons (PAHs) in the atmosphere. However, little is known about heterogeneous nitration rates of PAHs by gaseous NO2 on natural mineral substrates, such as desert dust...

The ability of the sepiolite mineral to intercalate CO2 molecules inside its channels in the presence of different alkaline cations (K+, Na+, and Li+) has been studied by classical molecular dynamics simulations. Starting from an alkaline-free sepiolite crystalline model, we built three models with stoichiometry Mg320Si440Al40O1200(OH)160X40·480H2O. On these models, we gradually replaced the wa...

The Mars Science Laboratory rover Curiosity found host rocks of basaltic composition and alteration assemblages containing clay minerals at Yellowknife Bay, Gale Crater. On the basis of the observed host rock and alteration minerals, we present results of equilibrium thermochemical modeling of the Sheepbed mudstones of Yellowknife Bay in order to constrain the formation conditions of its second...