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To explain the large values of the quadrupole splittings and line widths in the Mössbauer spectrum of oxybiotite, a formalized analysis of the distribution of effective charges in the anion network was conducted using an idealized model of the biotite octahedral layer. Based on this analysis, a qualitative physical model has been proposed, according to which the Mössbauer spectrum consists of a superposition of six quadrupole doublets. The proposed model explains the appearance of residual magnetization well below the biotite decomposition temperature. Annealing the biotite at 1070°K leads to the formation of nuclei of the magnetic phase in chains consisting of R3+ and vacancies. This phase is the decomposition product of biotite at 1370°K, i.e., a ferrispinel having Fe2−xMgAlxO4 (x = 0.5–0.6) composition.
Currently, the Affordable Care Act helps to provide inexpensive preventive care services to adolescents (10–19 years old) by preventing insurance companies from implementing cost-sharing measures. Some of these services can fall under the realm of mental health preventive care such as anxiety and depression testing. The lack of cost to a patient and their family encourages doctors to offer these services to their young patients. Furthermore, this Affordable Care Act provision - fosters doctor-patient communication because it normalizes mental health services as part of well-being. However, Braidwood Management Inc. v. Becerra threatens to have far reaching implications for preventive care policy and to disrupt health communication efforts to promote positive mental health. This Article uses structuration theory and a conceptual framework of adolescent development to examine the potential ramifications of cost-sharing on adolescent health. The implications of this change in cost-sharing include constraining doctors’ communication behavior in primary care settings and stunting healthy adolescent development. Ultimately, if the Braidwood decision is upheld, it may pose a challenge to a doctor’s ability to communicate with their young patient about mental health.
The adsorption of butanol, hexanol, and octanol on alkylammonium montmorillonites of different chain length is similar to the distribution of alcohol between an organic solvent and water in bulk solution. Successive expansion of the clay layers starts at critical alcohol/cation ratios of 0.6 or lower which are biased mean values due to the heterogeneity of the cation density of the mineral. In the interlamellar phase autoassociation of the alcohols occurs in contrast to their behavior in aqueous solution. The intrinsic association constants (kM ~ 7) are of the same magnitude of the values found in cyclohexane. The alcohols can associate with molecules fixed on specific sites of the mineral and on free monomers. The ratio of fixed to free monomers is of the order of 10/1.
Potassium release rates from micas varying widely in type and composition were measured. A sodium tetraphenylboron solution was used as the extracting agent. Muscovites were found to be two orders of magnitude more stable than a naturally occurring phlogopite and biotite. Synthetic fluorphlogopite was as stable as some muscovites. Lepidolite was the most stable mica. Primary factors affecting mica stability are thought to be: Hydroxyl bond orientation, isomorphous replacement of OH− by F−, the stronger Lewis base, and structural factors that lead to compression or stretching of the K—O bond.
The heterogeneity of the interlayer cation density and the corresponding mean layer charge density due to isomorphous substitution have been determined for six montmorillonite samples. This has been achieved by considering the transition of a monolayer to a double layer complex with alkylammonium ions. The transition is related to the interlayer cation density, together with the variation of the apparent spacings, which in turn is related to the composition of this two-component mixture.
All the samples showed a heterogeneous interlayer cation distribution and a differing mean charge density.
Organic solvent soluble organosilicate compounds retaining silicate backbone were obtained by the reaction between biotite and trimethylsilylating reagent. The soluble product which was formed at room temperature or at reflux temperature was a viscous liquid and was soluble in a wide range of organic solvents, but insoluble in water. Molecular weights of the soluble products and their thinlayer chromatograms made it clear that the soluble products consisted of several trimethylsilylated derivatives of silicic acids which were mainly the derivatives of mono- and disilicic acid. The influence of reaction temperature for the trimethylsilylation reaction also was discussed.
Hydroxy-carboxylic acids inhibit the crystallization of ferrihydrite in the pH range 9–11 in the order
citric > meso tartaric > L-tartaric ≫ lactic
and favor hematite formation relative to goethite in the order
L-tartaric > citric > meso tartaric > lactic.
The crystal shape of hematite can change from hexagonal plates to acicular in the presence of these acids. The influence of the acids on the crystallization rises with increasing concentration and with falling pH.
The effectiveness in suppressing crystallization depends on whether and how strongly the acid adsorbs on ferrihydrite and how strongly it complexes with Fe3+ in solution. Inhibition of crystallization of hematite is believed to be due to the di- and tricarboxylic acid linking ferrihydrite particles in an immobile network. Goethite formation is suppressed by the acid complexing with Fe in solution and hindering nucleation; strongly adsorbing acids also adsorb on the nuclei and hinder further growth. Certain acids can induce hematite formation because they contain a group which acts as a template for nucleation of hematite.