1 We compared the prevalence of signs and symptoms of chronic arsenic poisoning in two rural populations. 2 The arsenic concentration in the drinking water of the exposed population was 0.41 mg/l, and 0.007 mg/l in the control population. 3 The arsenic was present mainly (70%) in its pentavalent form. 4 The objective was to quantitate health effects and risks derived from chronic ingestion of arsenic in contaminated water. 5 In the exposed population, 21.6% of the sample, showed at least one of the cutaneous signs of chronic arsenic poisoning against 2.2% in the control town. 6 Non-specific symptoms were more prevalent in the exposed population and they occurred more frequently in those individuals with skin signs. 7 The relative risk of suffering a particular manifestation of poisoning, ranged from 1.9 to 36 times higher in the exposed population. 8 We estimated the risks above mentioned, which were derived from exposure to minute quantities of arsenic in a known proportion of its oxidation states during a life time period.
The electrostatic relationships necessary for the quantum-mechanical evaluation of the properties of a solute experiencing sudden changes in its internal charge distribution are here presented in a form suitable to perform accurate quantum-mechanical calculations of the solute properties. Attention has been paid to express the boundary conditions in the most convenient form and to avoid further constraints on the elaboration of the computational procedures. The approach exploits the separation of orientational (inertial) and electronic (inertialess) components of the polarization and complements the polarizable continuum method [Chem. Phys. 65, 239 (1982)], usually employed for static descriptions. Examples of application of the method to photoionization and electronic transitions processes are shown.
The alpha-beta anomer energy difference and the stability of 10 rotamers of counterclockwise D-glucopyranose were studied in vacuo and in aqueous solution at the B3LYP/6-31+G(d,p) level. To obtain the solute charge distribution and the solvent structure around it, we used the averaged solvent electrostatic potential from molecular dynamics method, ASEP/MD, which alternates molecular dynamics and quantum mechanics calculations in an iterative procedure. The main characteristics of the anomeric equilibrium, both in vacuo and in solution, are well reproduced. The relative stability of the different anomers is related to the availability of the free pairs of electrons in the anomeric oxygen to interact with the water molecules. The influence of solvation in the conformer equilibrium is also analyzed.
Articles you may be interested inResponse to "Comment on 'Solvatochromic shifts of polar and non-polar molecules in ambient and supercritical water: A sequential quantum mechanics/molecular mechanics study including solute-solvent electron exchangecorrelation"' [J. Chem. Phys.138, 217101 (2013)] J. Chem. Phys. 138, 217102 (2013); 10.1063/1.4807840 Solvatochromic shifts of polar and non-polar molecules in ambient and supercritical water: A sequential quantum mechanics/molecular mechanics study including solute-solvent electron exchange-correlation J. Chem. Phys. 137, 214504 (2012); 10.1063/1.4769124Density functional self-consistent quantum mechanics/molecular mechanics theory for linear and nonlinear molecular properties: Applications to solvated water and formaldehyde A complete active space self-consistent field multiconfiguration reference configuration interaction study of the potential energy curves of the ground and excited states of CCl
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.