Phase Rule and the Universality of Critical Phenomena in Chemically Reacting Liquid Mixtures.

Critical effects have been reported in the case of chemical equilibria, in which the solvent is a binary liquid mixture having a critical point of solution. At atmospheric pressure and for temperatures near the critical point, the critical effect manifests itself as a divergence in the temperature derivative of the extent of reaction. For a critical mixture of isobutyric acid + water (IBA/HO) serving as the solvent, we report experimental results for three complex equilibria involving (i) parallel dissolution of aluminum oxide and manganese dioxide (involves 8 species); (ii) parallel dissolution of aluminum oxide and copper(I) oxide (involves 10 species); and (iii) dissolution of barium chromate (involves 9 species).

Anomalous Solubility of an Inert Solid in a Binary Liquid Mixture with a Critical Point of Solution.

We consider the dissolution of a chemically inert solid in a binary liquid mixture with a critical point of solution. When the mixture, acting as the solvent, has come to equilibrium with the solid, the state of the system is completely described by the temperature, pressure, and a concentration variable formed by dividing the molar amount of one solvent component by that of the other. Under conditions of fixed pressure, the principle of critical point isomorphism predicts that the slope of a van't Hoff plot of the solubility of the solid should diverge toward infinity as the temperature enters the critical region.

Theory of First Order Chemical Kinetics at the Critical Point of Solution.

Liquid mixtures, which have a phase diagram exhibiting a miscibility gap ending in a critical point of solution, have been used as solvents for chemical reactions. The reaction rate in the forward direction has often been observed to slow down as a function of temperature in the critical region. Theories based upon the Gibbs free energy of reaction as the driving force for chemical change have been invoked to explain this behavior.

Large-volume protein crystal growth for neutron macromolecular crystallography.

Neutron macromolecular crystallography (NMC) is the prevailing method for the accurate determination of the positions of H atoms in macromolecules. As neutron sources are becoming more available to general users, finding means to optimize the growth of protein crystals to sizes suitable for NMC is extremely important. Historically, much has been learned about growing crystals for X-ray diffraction.

A chemical test of critical point isomorphism: reactive dissolution of ionic solids in isobutyric acid + water near the consolute point.

Binary liquid mixtures having a consolute point can be used as solvents for chemical reactions. When excess cerium(IV) oxide is brought into equilibrium with a mixture of isobutyric acid + water, and the concentration of cerium in the liquid phase is plotted in van't Hoff form, a straight line results for temperatures sufficiently in excess of the critical solution temperature. Within 1 K of the critical temperature, however, the concentration becomes substantially suppressed, and the van't Hoff slope diverges toward negative infinity.

Flow sorting and sequencing meadow fescue chromosome 4F.

The analysis of large genomes is hampered by a high proportion of repetitive DNA, which makes the assembly of short sequence reads difficult. This is also the case in meadow fescue (Festuca pratensis), which is known for good abiotic stress resistance and has been used in intergeneric hybridization with ryegrasses (Lolium spp.) to produce Festulolium cultivars.

Functional interfacing of Rhodospirillum rubrum chromatophores to a conducting support for capture and conversion of solar energy.

Owing to the considerable current interest in replacing fossil fuels with solar radiation as a clean, renewable, and secure energy source, light-driven electron transport in natural photosynthetic systems offers a valuable blueprint for conversion of sunlight to useful energy forms. In particular, intracytoplasmic membrane vesicles (chromatophores) from the purple bacterium Rhodospirillum rubrum provide a fully functional and robust photosynthetic apparatus, ideal for biophysical investigations of energy transduction and incorporation into biohybrid photoelectrochemical devices. These vesicular organelles, which arise by invagination of the cytoplasmic membrane, are the sites of the photochemical reaction centers and the light harvesting 1 (LH1) complex.

Managing emissions of active pharmaceutical ingredients from manufacturing facilities: an environmental quality standard approach.

Active pharmaceutical ingredient (API) residues have been found to be widespread in the aquatic environment, albeit in most cases at trace levels, with the route to the environment predominantly being via therapeutic use and subsequent excretion to sewer. Although manufacturing discharges may be a low overall contributor to environmental concentrations, they need to be managed effectively so that they do not adversely affect the local receiving environment. In order to achieve this, a risk-based approach is proposed that identifies the long-term and short-term concentrations, referred to as environmental reference concentrations (ERCs) and maximum tolerable concentrations (MTCs), respectively, of an API which should not be exceeded in the aquatic environment receiving effluent from pharmaceutical manufacturing sites.

Critical-point universality in adsorption: the effect of charcoal on a mixture of isobutyric acid and water near the consolute point.

The mixture of isobutyric acid and water has a consolute point at a temperature of 25.75 °C and mole fraction 0.1148 isobutyric acid.

A chemical test of the principle of critical point universality: the solubility of nickel (II) oxide in isobutyric acid + water near the consolute point.

A mixture of isobutyric acid + water has an upper consolute point at 38.8 mass % isobutyric acid and temperature near 26 °C. Nickel (II) oxide dissolves in this mixture by reacting with the acid to produce water and nickel isobutyrate.

Reaction kinetics and critical phenomena: iodination of acetone in isobutyric acid + water near the consolute point.

The rate of iodination of acetone has been measured as a function of temperature in the binary solvent isobutyric acid (IBA) + water near the upper consolute point. The reaction mixture was prepared by the addition of acetone, iodine, and potassium iodide to IBA + water at its critical composition of 38.8 mass % IBA.

Development and mapping of DArT markers within the Festuca - Lolium complex.

Background: Grasses are among the most important and widely cultivated plants on Earth. They provide high quality fodder for livestock, are used for turf and amenity purposes, and play a fundamental role in environment protection. Among cultivated grasses, species within the Festuca-Lolium complex predominate, especially in temperate regions.

Chemical equilibrium and critical phenomena: the solubilities of manganese dioxide and aluminum oxide in isobutyric acid + water near its consolute point.

We have measured the solubilities of manganese dioxide and aluminum oxide in isobutyric acid + water along its critical isopleth at temperatures above the upper critical solution temperature at 26.2 degrees C. Both oxides are basic anhydrides that react with isobutyric acid to produce the metal isobutyrate and water.

Reaction kinetics and critical phenomena: rates of some first order gas evolution reactions in binary solvents with a consolute point.

We have measured the rate of carbon dioxide evolution in the aniline catalyzed decomposition of acetone dicarboxylic acid in a mixture of isobutyric acid + water near its consolute point. Within a temperature interval of 1 degrees C, which included the critical solution temperature, the first-order rate constant oscillated in magnitude by about 10% as it passed through three complete cycles of slowing down followed by speeding up. Whereas we can find no ready explanation for the speeding up, we suggest that, because the mixture contained no inert components, the slowing down should belong to the Griffiths-Wheeler class of strong critical effects [Phys.

The use of concomitant medications in psychiatric inpatients treated with either olanzapine or other antipsychotic agents: a naturalistic study at a state psychiatric hospital.

Concomitant medications are frequently used in the treatment of resistant psychiatric conditions to augment the primary psychotropic agent or to ameliorate side effects. The present study evaluated the prescription of concomitant psychiatric medications for psychiatric inpatients that were prescribed either olanzapine at its first commercial availability or another first-line antipsychotic agent. Sixty-nine newly admitted patients (mainly with schizophrenia) who were prescribed either olanzapine (n = 35) or another first-line antipsychotic agent (n = 34) were assessed (for the prescription of other concomitant psychotropic drugs) before (2-4 weeks prior to study) and following 8 weeks of treatment (unless discharged sooner).