ISOTHERM OF SOLUBILITY MANGANESE SULFATE - MONOETHANOLAMINE - WATER AT 25 ° C

Solubility in the ternary system manganese sulfate - monoethanolamine - water at 25°C was studied by isothermal method. The equilibrium in the system was controlled by liquid phase analysis. True equilibrium in the system was established within 7 hours. The new compound was isolated in crystalline form and identified by the methods of chemical, graphic, X-ray and thermal analyses. It was found that the new compound is a crystalline substance with an individual set of interplanar distances and line intensities. The formation of the new compound NH2C2H4ON-MnSO4-3H2O which was identified by the methods of chemical, graphic and X-ray analyses has been established. Preliminary agrochemical tests of aqueous solution of the new compound showed its positive properties as a stimulant.

Quantification of PET infusion studies without true equilibrium: A tissue clearance correction

In some positron emission tomography (PET) studies, a reversibly binding radioligand is administered as a constant infusion to establish true equilibrium for quantification. This approach reduces scanning time and simplifies data analysis, but assumes similar behavior of the radioligand in plasma across the study population to establish true equilibrium in all subjects. Bias in outcome measurements can result if this assumption is not met. This work developed and validated a correction that reduces bias in total distribution volume ( VT) estimates when true equilibrium is not present. This correction, termed tissue clearance correction (TCC), took the form [Formula: see text], where β is the radioligand clearance rate in tissue, γ is a radiotracer-specific constant, and VT(A) is the apparent VT. Simulations characterized the robustness of TCC across imperfect values of γ and β and demonstrated reduction to false positive rates. This approach was validated with human infusion data for three radiotracers: [18F]FPEB, (−)-[18F]flubatine, and [11C]UCB-J. TCC reduced bias in VT estimates for all radiotracers and significantly reduced intersubject variance in VT for [18F]FPEB data in some brain regions. Thus, TCC improves quantification of data acquired from PET infusion studies.

Sustainable Slopes: Satisfying Rainfall-Erosion Equilibrium and Mechanical Stability

While manmade slopes are traditionally constructed with planar cross-sections, natural stable slopes are usually curvilinear with significant concavity of the profile. This concavity occurs as a result of evolutionary processes in which rain-driven erosion and sediment transport are balanced through slope shape adjustments. At the point of equilibrium, a relatively steady concavity with a uniform erosion rate is observed over time. Nevertheless, a true equilibrium state is possible only if mechanical stability is satisfied. In this study, concave profiles in rainfall erosion equilibrium were found based on the principles of the well-known RUSLE2 model. Results showed the existence of a family of steady shapes satisfying the condition of uniform normalized erosion rate. Those steady concave shapes that also satisfied long-term mechanical stability were then investigated. The overall results suggest that concave slopes can be constructed to achieve both minimal steady-state erosion equilibrium and mechanical stability, leading to more natural and sustainable landforms with minimal sediment delivery during initial slope adjustments. Keywords: Concave slopes, Erosion, Sustainable design, Slope stability.

A Study of the Brownian Transport in Straining Flows

The combined effects of Brownian forcing and straining flow on the statistical description of particle dynamics are considered. Using a Fokker-Planck (pdf) model results are obtained for both instantaneous and continuous releases of particles into the flow. The approach shows that continuous sources generate true equilibrium distributions, and highlights important features of these distributions that have implications for the closure modelling of third-order velocity moments.

Equilibrium Constants for Some Steps of the Reaction Cycle of the Sarcoplasmic Reticulum Calcium Pump

This paper summarizes true equilibrium measurements for some partial reactions of the sarcoplasmic reticulum calcium pump transport cycle. The most important result is the estimation of the equilibrium constant for the interconversion of the two major conformational states of the protein, E (Ca2+ binding sites facing the cytoplasm) and E′ (Ca2+ binding sides facing the sar­coplasmic reticulum lumen). The value of K0 = [E′]/[E] cannot be evaluated directly by any method available at present, but observed cooperativity in the binding of Mg2+ and Ca2+ to unliganded protein strongly indictes that K0 ⪢ 1. The most probable value, valid within an order of magnitude, is K0 ≃ 103, i.e., the E′ state is more stable than the E state by about 4 kcal/mol.