Use of remote patient monitoring kits to reduce hospitalization and mortality rates for patients with heart failure

PURPOSE

Patients with heart failure (HF) are at an increased risk of volume overload, which can lead to hospital admission. Use of noninvasive remote patient monitoring (RPM) devices utilizing biometric sensors and weighing scales to track vital signs and body weight has uncertain benefits. At the Baptist Health Louisville (BHLOU) HF Clinic, high-risk patients were given RPM kits. The purpose of this study was to determine whether RPM led to reductions in HF hospitalizations and mortality.

METHODS

This single-center, retrospective chart review evaluated adult patients presenting to the BHLOU HF Clinic after a recent hospitalization for HF or need for intravenous diuretics within the past 60 days. The study evaluated patients before and after implementation of RPM kits. The primary endpoints were differences in the rates of 30-day HF hospitalization and 30-day mortality. Secondary endpoints included differences in the number of interventions in 90 days, the 90-day rate of HF hospitalization, and the 90-day rate of mortality.

RESULTS

The final analysis included 58 patients in the preimplementation group and 34 patients in the postimplementation group. The rate of 30-day HF hospitalization was 10.3% in the preimplementation group and 0% in the postimplementation group. The rate of 30-day mortality was 3.4% in the preimplementation group and 0% in the postimplementation group. For the secondary endpoints, the number of interventions in 90 days was 3 vs 4, the 90-day rate of HF hospitalization was 22.4% vs 11.8%, and the rate of 90-day mortality was 6.9% vs 5.9% in the preimplementation vs postimplementation group, respectively.

CONCLUSION

Implementation of RPM in patients with acutely decompensated HF led to numerically lower 30-day and 90-day rates of HF hospitalization.

Effect of High-Dose Ergocalciferol on Rate of Falls in a Community-Dwelling, Home-Based Primary Care Veteran Population: A Case-Crossover Study

There was no difference identified in the rate of falls immediately prior to and following initiation of ergocalciferol 50,000 IU self-administered once weekly.

Dynamical and transport properties of liquid gallium at high pressures

Quantum molecular dynamics (QMD) simulations are used to calculate the equation of state, structure, and transport properties of liquid gallium along the principal shock Hugoniot. The calculated Hugoniot is in very good agreement with experimental data up to a pressure of 150 GPa as well as with our earlier classical molecular dynamics calculations using a modified embedded atom method (MEAM) potential. The self-diffusion and viscosity calculated using QMD agree with experimental measurements better than the MEAM results, which we attribute to capturing the complexity of the electronic structure at elevated temperatures. Calculations of the DC conductivity were performed around the Hugoniot. Above a density of 7.5 g/cm(3), the temperature increases rapidly along the Hugoniot, and the optical conductivity decreases, indicating simple liquid metal behavior.

Superconducting gap structure of the 115s revisited

Density functional theory calculations of the electronic structure of Ce- and Pu-based heavy fermion superconductors in the so-called 115 family are performed. The gap equation is used to consider which superconducting order parameters are most favorable assuming a pairing interaction that is peaked at (π, π, qz)—the wavevector for the antiferromagnetic ordering found in close proximity. In addition to the commonly accepted dx2−y2 order parameter, there is evidence that an extended s-wave order parameter with nodes is also plausible. We discuss whether these results are consistent with current observations and possible measurements that could help distinguish between these scenarios.

Understanding the complex phase diagram of uranium: the role of electron-phonon coupling

We report an experimental determination of the dispersion of the soft phonon mode along [100] in uranium as a function of pressure. The energies of these phonons increase rapidly, with conventional behavior found by 20 GPa, as predicted by recent theory. New calculations demonstrate the strong pressure (and momentum) dependence of the electron-phonon coupling, whereas the Fermi-surface nesting is surprisingly independent of pressure. This allows a full understanding of the complex phase diagram of uranium and the interplay between the charge-density wave and superconductivity.

First-principles study of stability of the bcc and ω phases of a low Al concentration Nb1-xAlx alloy

The phase stability and site occupancy of bcc (body centered cubic) Nb(5)Al and slightly rearranged atomic structures have been examined by means of first-principles calculations. In order to use first-principles methods, a periodic cell is required and we used ordered Nb(5)Al compounds as a tractable example of a low Al concentration Nb(1 - x)Al(x) alloy (in this case, for about 17 at.% Al). The instability against an ω-structure atomic displacement was also studied, since this structure is detrimental to ductility. Mulliken population analysis was used to provide an understanding of the hybridization between the atoms and the electronic origin of the site occupancy and instability of the underlying bcc structures. By making calculations for several different configurations of the Nb-Al system we estimated the strengths of the Nb-Nb and Nb-Al bonds. It is shown that the stability of the underlying bcc phases is directly related to Nb-Nb and Nb-Al first-nearest-neighbor interactions. The first-principles calculations were extended to finite temperature by including various contributions to the free energy. In particular, the vibrational free energy was calculated within the quasiharmonic approximation, and it is shown that the contribution of the low energy modes to the lattice entropy helps to stabilize ordered bcc phases against ω-type phase transformations. Semi-quasi-random structures were employed to study the stability of the ordered and disordered bcc phases. Our study showed, in agreement with experiment, that the ω, ordered, and disordered phases can coexist in a nonequilibrium state at finite temperature.

Elastic properties of the light actinides at high pressure

Using density-functional perturbation theory, we have calculated the elastic constants for the ground-state crystal structures of the light actinide metals both at their equilibrium volumes (for Th through Np) and as a function of pressure (for Th through U). As necessary, we take into account the effects of atomic relaxation and show that these can be neglected for α-U, but are crucial for α-Np. The elastic constants of Th and U are compared with experimental measurements near ambient conditions and good agreement is found. Studies of the Born stability criteria in pressure reveal that Th and Pa are mechanically unstable while U remains stable up to 85 GPa, as is observed in diamond anvil cell experiments.

Hubbard-U band-structure methods

The last decade has seen a large increase in the number of electronic-structure calculations that involve adding a Hubbard term to the local-density approximation band-structure Hamiltonian. The Hubbard term is then determined either at the mean-field level or with sophisticated many-body techniques such as using dynamical mean-field theory. We review the physics underlying these approaches and discuss their strengths and weaknesses in terms of the larger issues of electronic structure that they involve. In particular, we argue that the common assumptions made to justify such calculations are inconsistent with what the calculations actually do. Although many of these calculations are often treated as essentially first-principles calculations, in fact, we argue that they should be viewed from an entirely different point of view, namely, as based on phenomenological many-body corrections to band-structure theory. Alternatively, it may also be considered that they are just based on a Hubbard model that is more complex than the simple one- or few-band models traditionally used in many-body theories of solids.

Calculations for displacive ω-phase transformations in Ti-Al alloys with Nb additions at finite temperature

We examine by means of first-principles calculations the bcc-like (bcc: body centered cubic) to ω-like phase transformations in Ti-Al alloys with Nb additions at finite temperature. To simulate the alloy we use different discrete atomic configurations in a six atom unit cell of the stoichiometry Ti(3)Al(2)Nb. Calculated ground state energies show an instability in the ternary Ti(3)Al(2)Nb alloy against the ω structure type atomic displacement. To better understand the role of entropy in the stability/instability of these systems, the first-principles calculations are extended to finite temperature by including various contributions to the free energy. In particular, the vibrational free energy is calculated within a quasiharmonic approximation. It is shown that the bcc structure is stabilized by the contribution of the low energy modes to the lattice entropy against ω type atomic displacements. We find that configurational entropy plays a major role in the ω to B8(2) transformation. Calculated lattice parameters and transition temperatures are found to be in excellent agreement with experiment.

Phonon mechanisms and transformation paths in Pu

A long-standing problem in Pu science is the crystallographic mechanism for the delta-->alpha' (fcc-->monoclinic) transformation. Orientation relations between the two structures impose severe restrictions on the possible mechanisms and require the transition to be reconstructive, which we describe as a sequence of three displacive transitions: fcc-->trigonal-->hexagonal-->monoclinic. We predict instabilities along the Lambda and Sigma branches in the phonon dispersion of the delta phase and formulate a free energy to describe the displacement of atoms across the transition. We suggest that the delta-->alpha' transition in Pu lies at the threshold of a change in character of the orientation relationship from lighter to heavier actinides, correlating with changes in electron itinerancy, magnetism, and volume.

New pseudophase structure for alpha-Pu

We propose a new pseudophase crystal structure, based on an orthorhombic distortion of the diamond structure, for the ground-state alpha phase of plutonium. Electronic-structure calculations in the generalized-gradient approximation give approximately the same total energy for the two structures. Interestingly, our new pseudophase structure is the same as the gamma-Pu structure except with very different b/a and c/a ratios. We show how the contraction relative to the gamma phase, principally in the z direction, leads to an alpha-like structure in the [0,1,1] plane and reproduces the short range bonds of the alpha phase. This is an important link between two complex structures of Pu and opens new possibilities for exploring the very rich phase diagram of Pu through theoretical calculations.

Extended X-ray absorption fine structure measurements of laser-shocked V and Ti and crystal phase transformation in Ti

Extended x-ray absorption fine structure (EXAFS), using a laser-imploded target as a source, can yield the properties of laser-shocked metals on a nanosecond time scale. EXAFS measurements of vanadium shocked to approximately 0.4 Mbar yield the compression and temperature in good agreement with hydrodynamic simulations and shock-speed measurements. In laser-shocked titanium at the same pressure, the EXAPS modulation damping is much higher than is warranted by the predicted temperature increase. This is shown to be due to the alpha-Ti to omega-Ti crystal phase transformation, known to occur below approximately 0.1 Mbar for slower shock waves.

New mechanism for the alpha to omega martensitic transformation in pure titanium

We propose a new direct mechanism for the pressure driven alpha-->omega martensitic transformation in pure titanium. A systematic algorithm enumerates all possible pathways whose energy barriers are evaluated. A new, homogeneous pathway emerges with a barrier at least 4 times lower than other pathways. The pathway is shown to be favorable in any nucleation model.

Three-dimensional elastic compatibility and varieties of twins in martensites

We model a cubic-to-tetragonal martensitic transition by a Ginzburg-Landau free energy in the symmetric strain tensor. We show in three dimensions (3D) that solving the St. Venant compatibility relations for strain, treated as independent field equations, generates three anisotropic long-range potentials between the two order parameter components. These potentials encode 3D discrete symmetries, express the energetics of lattice integrity, and determine 3D textures. Simulation predictions include twins with temperature-varying orientation, helical twins, competing metastable states, and compatibility-induced elastic frustration. Our approach also applies to improper ferroelastics.