Chemical quality of bottled waters: a review

Bottled water has become very popular for quenching thirst and as a dietary (mineral) supplement. The plethora of natural mineral waters precludes any unequivocal system of classification, which makes it difficult for the consumer to choose a water with properties that suits him/her exactly. The ever-increasing popularity of bottled waters means that it is of the utmost importance to determine not only their mineral content, but above all, the content of possible contaminants, especially organic ones. In this respect bottled waters are a special case, because apart from organic contamination from the environment, the water may become secondarily contaminated as a result of its being improperly transported and stored. Pesticides, volatile organic compounds, and carbonyl compounds have been detected in samples of bottled water. This overview shows the available published information on levels of inorganic constituents and organic contaminants in samples of bottled water in the context of sample preparation procedures and analytical techniques.     

Glutamate receptor-mediated restoration of experience-dependent place field expansion plasticity in aged rats.

Place fields of hippocampal pyramidal cells expand asymmetrically when adult rats repeatedly follow the same route. This behaviorally induced expression of neuronal plasticity uses an NMDAR-dependent, LTP-like mechanism and could be used by hippocampal networks to store information. Aged spatial memory-impaired rats exhibit defective experience-dependent place field expansion plasticity. One possible explanation for this aged-associated deficit is alterations in glutamatergic function. In fact, both NMDAR- and AMPAR-mediated field excitatory postsynaptic potentials in CA1 decrease with aging. The current study investigated whether modulation of either AMPA or NDMA receptor activity could restore this experience-dependent plasticity by prolonging AMPAR activity with the ampakine CX516 and modulating the NMDAR with the noncompetitive antagonist memantine. The spatial firing characteristics of multiple CA1 pyramidal cells were monitored under both treatment conditions as aged rats repeatedly traversed a circular track. Compared to the saline baseline condition, acute administration of memantine, but not CX516, reinstated experience-dependent place field expansion. Taken together, these data suggest that pharmacological manipulation of the NMDAR can improve the function of hippocampal networks critical to optimal cognition in aging. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alternative Local Melting-Solidification of Suspended Nanoparticles for Heterostructure Formation Enabled by Pulsed Laser Irradiation

Phase formation by pulsed laser irradiation of suspended nanoparticles has recently been introduced as a promising synthesis technique for heterostructures. The main challenge still lingers regarding the exact mechanism of particle formation due to the non-equilibrium kinetic by-products resulting from the localized alternative, fast, high-temperature nature of the process. Here, the authors analyze the bond breaking/formation of copper or copper (II) interfaces with ethanol during the absorption of pulses for Cu-CuO-Cu₂O formation applicable as an electrocatalyst in ethanol oxidation fuel cells. This study includes but is not limited to, a comprehensive discussion of the interaction between nano-laser pulses and suspension for practical control of the synthesis process. The observed exponential and logarithmic changes in the content of heterostructures for the CuO-ethanol and Cu-ethanol samples irradiated with different fluences are interpreted as the dominant role of physical and chemical reactions, respectively, during the pulsed laser irradiation of suspensions synthesis. It is also shown that the local interface between dissociated ethanol and the molten sphere is responsible for the oxidative/reductive interactions resulting in the formation of catalytic-augmented Cu³⁺ by-product, thanks to the reactive bond force field molecular dynamics studies confirmed by ab-initio calculations and experimental observations.