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Substance P (SP) acts as a neurotransmitter in the neostriatum through the axon collaterals of spiny projection neurons. However, possible direct or indirect actions of SP on the neostriatal output neurons have not been described. Targets of SP terminals within the neostriatum include interneurons, spiny neurons, afferent fibers and boutons. SP induces the release of both dopamine (DA) and acetylcholine (ACh). Since some postsynaptic actions of both DA and ACh on spiny neurons are known, we asked if activation of neostriatal NK1-class receptors is able to reproduce them. The SP NK1-receptor agonist, GR73632 (1 microM), had both excitatory and inhibitory actions on virtually all spiny neurons tested at resting potential. The excitatory action was blocked by atropine and coursed with an increase in firing rate and input resistance (R(N)). The inhibitory action was blocked by haloperidol and coursed with a reduction in firing rate and R(N). Therefore, the release of both DA and ACh induced by NK1-receptor activation modulates indirectly the excitability of the projection neurons. SP facilitates the actions of these transmitters on the spiny neuron. A residual excitatory response to the NK1-receptor agonist was observed in 30% of a sample of neurons tested in the presence of both haloperidol and atropine. The increase in R(N) that accompanied this response could be observed in the presence of 1 microM TTX or 100 microM Cd2+, suggesting a direct effect. Double labeling showed that only SP-immunoreactive neurons were facilitated by NK1-receptor activation in these conditions.

Limited water resources and greenhouse gas emissions from fossil fuels used in electricity production are problems experienced in Chile. To address water shortages, many copper mining companies have started to use seawater or desalinated water in their operations. However, seawater exerts a negative impact on the mineral processing operation. It reduces the recovery of copper and molybdenum minerals in the flotation of copper−molybdenum sulfide ores due to the presence of calcium and magnesium ions. This study aims to propose a partial desalination treatment for calcium and magnesium species removal to improve the recovery of valuable minerals in the flotation of copper−molybdenum sulfide ores. The proposed method uses carbon dioxide gas and sodium hydroxide to promote the removal of calcium and magnesium ions from seawater. As a result, the partial desalination treatment can remove 60.5% of calcium and 98.3% of magnesium species. In addition, it helped in reaching a high recovery of molybdenum (81.1%) and copper (93.4%) as well as depressed pyrite (0.95% of iron) in the flotation of copper−molybdenum sulfide ores. Therefore, partial desalination treatment could provide the appropriate water quality required in the froth flotation process and it could reduce carbon dioxide from greenhouse gas emissions.

Mining activities are among the main sources of potentially toxic elements (PTEs) in the environment which constitute a real concern worldwide, especially in developing countries. These activities have been carried out for more than a century in Chile, South America, where, as evidence of incorrect waste disposal practices, several abandoned mining waste deposits were left behind. This study aimed to understand multi-elements geochemistry, source patterns and mobility of PTEs in soils of the Taltal urban area (northern Chile). Topsoil samples (n = 125) were collected in the urban area of Taltal city (6 km 2 ) where physicochemical properties (redox potential, electric conductivity and pH) as well as chemical concentrations for 35 elements were determined by inductively coupled plasma optical emission spectrometer. Data were treated following a robust workflow, which included factor analysis (based on ilr-transformed data), a new robust compositional contamination index (RCCI), and fractal/multi-fractal interpolation in GIS environment. This approach allowed to generate significant elemental associations, identifying pool of elements related either to the geological background, pedogenic processes accompanying soil formation or to anthropogenic activities. In particular, the study eventually focused on a pool of 6 PTEs (As, Cd, Cr, Cu, Pb, and Zn), their spatial distribution in the Taltal city, and the potential sources and mechanisms controlling their concentrations. Results showed Arturo Reyes and Matar Thiombane have contributed equally to this work.