Controlled Release Kinetics in Hydroxy Double Salts: Effect of Host Anion Structure

Nanodimensional layered metal hydroxides such as layered double hydroxides (LDHs) and hydroxy double salts (HDSs) can undergo anion exchange reactions releasing intercalated anions. Because of this, these metal hydroxides have found applications in controlled release delivery of bioactive species such as drugs and pesticides. In this work, isomers of hydroxycinnamate were used as model compounds to systematically explore the effects of anion structure on the rate and extent of anion release in HDSs. Following intercalation and subsequent release of the isomers, it has been demonstrated that the nature and position of substituent groups on intercalated anions have profound effects on the rate and extent of release.The extent of release was correlated with the magnitude of dipole moments while the rate of reaction showed strong dependence on the extent of hydrogen bonding within the layers.The orthoisomer showed a more sustained and complete release as compared to the other isomers

Marketing in Higher Education: A Stage Model Concerning Where It\u27s Been and Where It\u27s Going

The ideas of Williford (1987) are used to propose a four-stage model describing the evolution of marketing in many colleges and universities. It elaborates on the thinking endemic to strategic marketing management and frameworks drawn from business marketing which will likely become more prominent in higher education. (Author/GLR

The Witt Ring of a Curve with Good Reduction over a Non-dyadic Local Field

In this work, we present a generalization to varieties and sheaves of the fundamental ideal of the Witt ring of a field by defining a sheaf of fundamental ideals $\tilde{I}$ and a sheaf of Witt rings $\tilde{W}$ in the obvious way. The Milnor conjecture then relates the associated graded of $\tilde{W}$ to Milnor K-theory and so allows the classical invariants of a bilinear space over a field to be extended to our setting using \'etale cohomology. As an application of these results, we calculate the Witt ring of a smooth curve with good reduction over a non-dyadic local field

Molecular dissection of I(A) in cortical pyramidal neurons reveals three distinct components encoded by Kv4.2, Kv4.3, and Kv1.4 alpha-subunits

The rapidly activating and inactivating voltage-gated K(+) (Kv) current, I(A), is broadly expressed in neurons and is a key regulator of action potential repolarization, repetitive firing, backpropagation (into dendrites) of action potentials, and responses to synaptic inputs. Interestingly, results from previous studies on a number of neuronal cell types, including hippocampal, cortical, and spinal neurons, suggest that macroscopic I(A) is composed of multiple components and that each component is likely encoded by distinct Kv channel alpha-subunits. The goals of the experiments presented here were to test this hypothesis and to determine the molecular identities of the Kv channel alpha-subunits that generate I(A) in cortical pyramidal neurons. Combining genetic disruption of individual Kv alpha-subunit genes with pharmacological approaches to block Kv currents selectively, the experiments here revealed that Kv1.4, Kv4.2, and Kv4.3 alpha-subunits encode distinct components of I(A) that together underlie the macroscopic I(A) in mouse (male and female) cortical pyramidal neurons. Recordings from neurons lacking both Kv4.2 and Kv4.3 (Kv4.2(-/-)/Kv4.3(-/-)) revealed that, although Kv1.4 encodes a minor component of I(A), the Kv1.4-encoded current was found in all the Kv4.2(-/-)/Kv4.3(-/-) cortical pyramidal neurons examined. Of the cortical pyramidal neurons lacking both Kv4.2 and Kv1.4, 90% expressed a Kv4.3-encoded I(A) larger in amplitude than the Kv1.4-encoded component. The experimental findings also demonstrate that the targeted deletion of the individual Kv alpha-subunits encoding components of I(A) results in electrical remodeling that is Kv alpha-subunit specific

Photoinduced Removal of Nifedipine Reveals Mechanisms of Calcium Antagonist Action on Single Heart Cells

The currents through voltage-activated calcium channels in heart cell membranes are suppressed by dihydropyridine calcium antagonists such as nifedipine. Nifedipine is photolabile, and the reduction of current amplitude by this drug can be reversed within a few milliseconds after a 1-ms light flash. The blockade by nifedipine and its removal by flashes were studied in isolated myocytes from neonatal rat heart using the whole-cell clamp method. The results suggest that nifedipine interacts with closed, open, and inactivated calcium channels. It is likely that at the normal resting potential of cardiac cells, the suppression of current amplitude arises because nifedipine binds to and stabilizes channels in the resting, closed state. Inhibition is enhanced at depolarized membrane potentials, where interaction with inactivated channels may also become important. Additional block of open channels is suggested when currents are carried by Ba^(2+) but is not indicated with Ca^(2+) currents. Numerical simulations reproduce the experimental observations with molecular dissociation constants on the order of 10^(-7) M for closed and open channels and 10^(-8) M for inactivated channels

Financing the U.S. Health System: Issues and Options for Change

Explores key issues of health reform and options for financing health care -- redirecting funds to more effective uses, rolling back tax cuts, modifying tax exclusions for health benefits, an employer play-or-pay model, and a value-added tax

Partitioning strategy for efficient nonlinear finite element dynamic analysis on multiprocessor computers

A computational procedure is presented for the nonlinear dynamic analysis of unsymmetric structures on vector multiprocessor systems. The procedure is based on a novel hierarchical partitioning strategy in which the response of the unsymmetric and antisymmetric response vectors (modes), each obtained by using only a fraction of the degrees of freedom of the original finite element model. The three key elements of the procedure which result in high degree of concurrency throughout the solution process are: (1) mixed (or primitive variable) formulation with independent shape functions for the different fields; (2) operator splitting or restructuring of the discrete equations at each time step to delineate the symmetric and antisymmetric vectors constituting the response; and (3) two level iterative process for generating the response of the structure. An assessment is made of the effectiveness of the procedure on the CRAY X-MP/4 computers

The Cotton Wizard: A Software Implementation of a Cotton Variety Selection Model

The Cotton Wizard is an implementation of a cotton variety selection model intended to assist decision-makers (including producers, farm managers, extension specialists, and breeders) in variety selection. The program uses objective cotton performance test data available from state agricultural experiment stations. The decision criteria for variety selection are based on expected economic return (mean net revenue) of a variety and the variability of returns (coefficient of variation). Total revenue is calculated from lint price and seed price, and lint and seed yields. Lint and seed prices are determined by their respective quality characteristics. Adjustments are made for costs that may differ among varieties, such as planting seed cost (seed and technology costs), harvest and ginning costs, and herbicide and insecticide costs in comparisons of transgenic and conventional varieties. Users are provided with information on varieties—such as mean net revenue (total revenue less costs), variability in net revenue, and agronomic characteristics—to aid in the decision process. The Cotton Wizard is available as a Web application.Crop Production/Industries, Farm Management, Production Economics,