Improving Safety in the First Hour Following Total Joint Replacement Surgery

The purpose of this systems change project was to review and analyze the literature as well as evaluate patient data related to the practice of bypassing the post anesthesia recovery room (PACU), or Phase 1 recovery, in a Critical Access Hospital. The overarching question for this project was: When is it safe for the total joint replacement patient receiving spinal anesthesia with or without sedation to bypass Phase 1 recovery in a Critical Access Hospital? Methods: This project was grounded in Participative Action Research, Change Theory and the nursing theory of Relationship Based Care. A chart review of 168 patients who had total joint replacement surgery over a 6 month period was completed during summer 2011. Data abstracted included pre-surgical data: age, body mass index, and ASA score as well as post-surgical data: Aldrete score, patient vital signs including mean arterial pressure (MAP), type and length of surgery, estimated blood loss during surgery, need for oxygen supplementation, nausea, vomiting, itching, and pain. Results: Of the total sample of 168 patients, 66 (39.3 %) had an Aldrete score of less than or equal to 7 in the first hour postoperatively, 32 (19%) had a MAP ≤ to 63 in the first hour and 21 (12.5%) had a MAP ≤ to 60. Age, ASA scores and BMI were not associated with decreased Aldrete scores or MAP. Patients with total hip arthroplasty and bilateral total knee arthroplasty had a higher incidence of lower Aldrete scores and lower MAP than unilateral total knee arthroplasty patients. Conclusions: Because nearly 40% of the sample had Aldrete scores of 7 or less within the first hour postoperatively, and most PACUs have as one of the criterion for discharge as Aldrete scores of 8 or higher, it is clear that patients who receive total joint replacement arthroplasty in this setting should receive a higher level of nursing care in the immediate postoperative hour

Microbubble shape oscillations excited through ultrasonic parametric driving\ud

An air bubble driven by ultrasound can become shape-unstable through a parametric instability. We report time-resolved optical observations of shape oscillations (mode n=2 to 6) of micron-sized single air bubbles. The observed mode number n was found to be linearly related to the ambient radius of the bubble. Above the critical driving pressure threshold for shape oscillations, which is minimal at the resonance of the volumetric radial mode, the observed mode number n is independent of the forcing pressure amplitude. The microbubble shape oscillations were also analyzed numerically by introducing a small nonspherical linear perturbation to a Rayleigh-Plesset-type equation, capturing the experimental observations in detail.\ud \u

An Improved Approach for Measurement of Coupled Heat and Water Transfer in Soil Cells

Laboratory experiments on coupled heat and water transfer in soil have been limited in their measurement approaches. Inadequate temperature control creates undesired two-dimensional distributions of both temperature and moisture. Destructive sampling to determine soil volumetric water content (θ) prevents measurement of transient θ distributions and provides no direct information on soil thermal properties. The objectives of this work were to: (i) develop an instrumented closed soil cell that provides one-dimensional conditions and permits in situ measurement of temperature, θ, and thermal conductivity (λ) under transient boundary conditions, and (ii) test this cell in a series of experiments using four soil type–initial θ combinations and 10 transient boundary conditions. Experiments were conducted using soil-insulated cells instrumented with thermo-time domain reflectometry (T-TDR) sensors. Temperature distributions measured in the experiments show nonlinearity, which is consistent with nonuniform thermal properties provided by thermal moisture distribution but differs from previous studies lacking one-dimensional temperature control. The T-TDR measurements of θ based on dielectric permittivity, volumetric heat capacity, and change in volumetric heat capacity agreed well with post-experiment sampling, providing r 2 values of 0.87, 0.93, and 0.95, respectively. Measurements of θ and λ were also consistent with the shapes of the observed temperature distributions. Techniques implemented in these experiments allowed observation of transient temperature, θ, and λ distributions on the same soil sample for 10 sequentially imposed boundary conditions, including periods of rapid redistribution. This work demonstrates that, through improved measurement techniques, the study of heat and water transfer processes can be expanded in ways previously unavailable

Allosteric modulators of the hERG K+ channel Radioligand binding assays reveal allosteric characteristics of dofetilide analogs

Medicinal Chemistr

Structure-Affinity Relationships and Structure-Kinetics Relationships of Pyrido[2,1-f]purine-2,4-dione Derivatives as Human Adenosine A(3) Receptor Antagonists

We expanded on a series of pyrido[2,1-f]purine-2,4-clione derivatives as human adenosine A(3) receptor (hA(3)R) antagonists to determine their kinetic profiles and affinities. Many compounds showed high affinities and a diverse range of kinetic profiles. We found hA(3)R antagonists with very short residence time (RT) at the receptor (2.2 min for 5) and much longer RTs (e.g., 376 min for 27 or 391 min for 31). Two representative antagonists (5 and 27) were tested in [S-35]GTP gamma S binding assays, and their RTs appeared correlated to their (in)surmountable antagonism. From a k(on)-k(off)-K-D kinetic map, we divided the antagonists into three subgroups, providing a possible direction for the further development of hA(3)R antagonists. Additionally, we performed a computational modeling study that sheds light on the crucial receptor interactions, dictating the compounds' binding kinetics. Knowledge of target binding kinetics appears useful for developing and triaging new hA(3)R antagonists in the early phase of drug discovery

Structure-Affinity Relationships and Structure-Kinetics Relationships of Pyrido[2,1-f]purine-2,4-dione Derivatives as Human Adenosine A(3) Receptor Antagonists

We expanded on a series of pyrido[2,1-f]purine-2,4-clione derivatives as human adenosine A(3) receptor (hA(3)R) antagonists to determine their kinetic profiles and affinities. Many compounds showed high affinities and a diverse range of kinetic profiles. We found hA(3)R antagonists with very short residence time (RT) at the receptor (2.2 min for 5) and much longer RTs (e.g., 376 min for 27 or 391 min for 31). Two representative antagonists (5 and 27) were tested in [S-35]GTP gamma S binding assays, and their RTs appeared correlated to their (in)surmountable antagonism. From a k(on)-k(off)-K-D kinetic map, we divided the antagonists into three subgroups, providing a possible direction for the further development of hA(3)R antagonists. Additionally, we performed a computational modeling study that sheds light on the crucial receptor interactions, dictating the compounds' binding kinetics. Knowledge of target binding kinetics appears useful for developing and triaging new hA(3)R antagonists in the early phase of drug discovery

Method for Maintaining One-Dimensional Temperature Gradients in Unsaturated, Closed Soil Cells

One-dimensional temperature gradients are difficult to achieve in nonisothermal laboratory studies because, in addition to desired axial temperature gradients, ambient temperature interference (ATI) creates a radial temperature distribution. Our objective was to develop a closed soil cell with limited ATI. The cell consists of a smaller soil column, the control volume, surrounded by a larger soil column, which provides radial insulation. End boundary temperatures are controlled by a new spiral-circulation heat exchanger. Four cell size configurations were tested for ATI under varying ambient temperatures. Results indicate that cells with a 9-cm inner column diameter, 5-cm concentric soil buffer, and either 10- or 20-cm length effectively achieved one-dimensional temperature conditions. At 30°C ambient temperature, and with axial temperature gradients as large as 1°C cm−1, average steady-state radial temperature gradients in the inner soil columns were−1 Thus, these cell configurations meet the goal of maintaining a one-dimensional temperature distribution. These cells provide new opportunities for improving the study of coupled heat and water movement in soil

On Superluminal motions in photon and particle tunnelings

It is shown that the Hartman-Fletcher effect is valid for all the known expressions of the mean tunnelling time, in various nonrelativistic approaches, for the case of finite width barriers without absorption. Then, we show that the same effect is not valid for the tunnelling time mean-square fluctuations. On the basis of the Hartman-Fletcher effect and the known analogy between photon and nonrelativistic-particle tunnelling, one can explain the Superluminal group-velocities observed in various photon tunnelling experiments (without violation of the so-called "Einstein causality").Comment: standard LaTeX file; accepted for publication in Phys. Lett.

Numerical Test of Disk Trial Wave function for Half-Filled Landau Level

The analyticity of the lowest Landau level wave functions and the relation between filling factor and the total angular momentum severely limits the possible forms of trial wave functions of a disk of electrons subject to a strong perpendicular magnetic field. For N, the number of electrons, up to 12 we have tested these disk trial wave functions for the half filled Landau level using Monte Carlo and exact diagonalization methods. The agreement between the results for the occupation numbers and ground state energies obtained from these two methods is excellent. We have also compared the profile of the occupation number near the edge with that obtained from a field-theoretical method. The results give qualitatively identical edge profiles. Experimental consequences are briefly discussed.Comment: To be published in Phys. Rev. B. 9 pages, 6 figure