Acute Kidney Injury and Lower Extremity Orthopedic Surgery: A Targeted Education on AKI Risk Factors

BACKGROUND: Total knee and total hip replacement surgery is highly effective for relieving pain and improving functionality. Though effective, the surgery is not without risk. Acute kidney injury (AKI) can develop following joint replacement surgery and has been shown to increase morbidity, mortality, hospital costs, and length of stay. There are several risk factors associated with the development of AKI – some of which are modifiable. METHODS: This quality improvement project implements an educational module with the goal of educating staff on the risk factors for developing AKI and evidence-based recommendations surrounding perioperative management for total joint arthroplasty (TJA). Using Johns Hopkins Nursing Evidence-Based Practice Model, a three-step process called PET: practice question, evidence, and translation will be used to implement a pre-test, educational video, and post-test. INTERVENTION: Anesthesia providers will be given a pre-test to assess their current knowledge of factors affecting the development of AKI. Immediately following this test, the educational video will be viewed. After watching, a post-test will be administered to the providers to assess if there is an increase in knowledge. RESULTS: 53 anesthesia providers took this module. The mean pre-test score before the education video was 6.64 points out of the maximum score of 10 points. The mean post-test score after watching the education video was 9.08 points out of 10 points. After conducting a paired two sample t-test the resulting p-value was \u3c 0.00, therefore statistically significant. CONCLUSIONS: The educational video increased knowledge of risk factors for the development of AKI and evidence-based recommendations

Development of a Novel Fistula Occlusion Device

Fistulas are a pathological tunnel between two hollow organs or an organ and the skin. There is currently no gold-standard for treatment as invasive surgical procedures carry significant morbidity, and potential for failure; many patients are also not surgical candidates due to comorbid conditions. Patients’ with fistulas have high mortality rates and a poor quality of life. The goal of this thesis was to develop a prototype and computational model of a minimally invasive fistula occlusion device. The prototype was designed to be an electromagnetic catheter that could deliver a glue plug to a precise location. It used a solenoid to control the magnetic field and plug delivery. The design of the prototypes went through several stages before arriving at the final construction. Various materials were attempted for the solenoid core and a range of wire sizes for the copper coil. The final manufacturing process involves alternating coats of iron paint and iron wire for the core with a copper wire coil. Horizontal and vertical magnetic force experiments were conducted to analyze the effects of core size. Three different sized cores were built to determine how much iron was needed to achieve a clinically relevant magnetic force. It was demonstrated that it is possible to achieve the necessary force using hollow solenoids. A computational model was built in MATLAB so that the researchers could analyze a greater range of design parameters moving forward. Validation and verification of the model has shown magnetic field shapes consistent with solenoid theory. The results of this study indicate that the ideas presented in the preliminary patent filed in July of 2015 are feasible. Further refinement is necessary to create the final device to be used in patients but it is possible to develop an electromagnetic catheter to control small plugs for fistula repair

The Dynamics of Dense Cores in the Perseus Molecular Cloud II: The Relationship Between Dense Cores and the Cloud

We utilize the extensive datasets available for the Perseus molecular cloud to analyze the relationship between the kinematics of small-scale dense cores and the larger structures in which they are embedded. The kinematic measures presented here can be used in conjunction with those discussed in our previous work as strong observational constraints that numerical simulations (or analytic models) of star formation should match. We find that dense cores have small motions with respect to the 13CO gas, about one third of the 13CO velocity dispersion along the same line of sight. Within each extinction region, the core-to-core velocity dispersion is about half of the total (13CO) velocity dispersion seen in the region. Large-scale velocity gradients account for roughly half of the total velocity dispersion in each region, similar to what is predicted from large-scale turbulent modes following a power spectrum of P(k) ~ k^{-4}.Comment: Accepted for publication in ApJ. 47 pages (preprint format), 20 figures, 5 table

Matrix cadmium accumulation depolarizes mitochondria isolated from mouse brain

Cadmium (Cd2+) is an environmental contaminant commonly found in industrial settings with a biological half-life of 30 years. Although the accumulation and subsequent cytotoxicity of Cd2+ in nervous tissue is well documented, it is unclear exactly how Cd2+ kills cells. One potential mechanism involves inhibition of cellular energy production. In this study, we used fluorescence microscopy to monitor the effects of Cd2+ on mitochondrial membrane potential (ΔΨm) in individual mitochondria isolated from mouse brain. Mitochondria were attached to microscopy glass and loaded with rhodamine 123, a fluorescent indicator that collects in energized and respiring mitochondria, i.e., those with a robust ΔΨm. We found that Cd2+ at relatively low concentrations quickly and completely abolished ΔΨm. Cd2+ actions were concentration- dependent, and were relatively potent and efficacious when compared to calcium (Ca2+) and zinc (Zn2+). Moreover, the Ca2+ uniporter blocker ruthenium red protected against Cd2+-induced depolarization, suggesting that matrix entry of Cd2+ through this traditional Ca2+ pathway is necessary for its effect. These results demonstrate that Cd2+ substantially inhibits mitochondrial function and provide important insight regarding the mechanism of Cd2+-mediated neurotoxicity

The Perils of Clumpfind: The Mass Spectrum of Sub-structures in Molecular Clouds

We study the mass spectrum of sub-structures in the Perseus Molecular Cloud Complex traced by 13CO (1-0), finding that $dN/dM\propto M^{-2.4}$ for the standard Clumpfind parameters. This result does not agree with the classical $dN/dM\propto M^{-1.6}$. To understand this discrepancy we study the robustness of the mass spectrum derived using the Clumpfind algorithm. Both 2D and 3D Clumpfind versions are tested, using 850 $\mu$m dust emission and 13CO spectral-line observations of Perseus, respectively. The effect of varying threshold is not important, but varying stepsize produces a different effect for 2D and 3D cases. In the 2D case, where emission is relatively isolated (associated with only the densest peaks in the cloud), the mass spectrum variability is negligible compared to the mass function fit uncertainties. In the 3D case, however, where the 13CO emission traces the bulk of the molecular cloud, the number of clumps and the derived mass spectrum are highly correlated with the stepsize used. The distinction between "2D" and "3D" here is more importantly also a distinction between "sparse" and "crowded" emission. In any "crowded" case, Clumpfind should not be used blindly to derive mass functions. Clumpfind's output in the "crowded" case can still offer a statistical description of emission useful in inter-comparisons, but the clump-list should not be treated as a robust region decomposition suitable to generate a physically-meaningful mass function. We conclude that the 13CO mass spectrum depends on the observations resolution, due to the hierarchical structure of MC.Comment: 5 pages, 3 figures. Accepted for publication in ApJ Letter

The COMPLETE Survey of Star-Forming Regions: Phase I Data

We present an overview of data available for the Ophiuchus and Perseus molecular clouds from ``Phase I'' of the COMPLETE Survey of Star-Forming Regions. This survey provides a range of data complementary to the Spitzer Legacy Program ``From Molecular Cores to Planet Forming Disks.'' Phase I includes: Extinction maps derived from 2MASS near-infrared data using the NICER algorithm; extinction and temperature maps derived from IRAS 60 and 100um emission; HI maps of atomic gas; 12CO and 13CO maps of molecular gas; and submillimetre continuum images of emission from dust in dense cores. Not unexpectedly, the morphology of the regions appears quite different depending on the column-density tracer which is used, with IRAS tracing mainly warmer dust and CO being biased by chemical, excitation and optical depth effects. Histograms of column-density distribution are presented, showing that extinction as derived from 2MASS/NICER gives the closest match to a log-normal distribution as is predicted by numerical simulations. All the data presented in this paper, and links to more detailed publications on their implications are publically available at the COMPLETE website.Comment: Accepted by AJ. Full resolution version available from: http://www.cfa.harvard.edu/COMPLETE/papers/complete_phase1.pd

Retrospective Cohort Evaluating the Comparative Effectiveness of Ceftaroline and Daptomycin as First-Line Therapies for Inpatient Treatment of Diabetic Foot Infection in the United States Veterans Health Care System

Background Both ceftaroline and daptomycin are possible therapeutic options for diabetic foot infection (DFI) and both are active against methicillin-resistant Staphylococcus aureus (MRSA) infection; however, no previous studies have evaluated their efectiveness head-to-head. Objective This study compared hospital readmission and mortality proportions among patients receiving ceftaroline fosamil or daptomycin for DFI. Patients and Methods This was a retrospective cohort, comparative efectiveness study of adults (aged ≥ 18 years) admitted to United States Veterans Health Care System hospitals with a diagnosis code for DFI between 1 October 2010 and 30 September 2014 with an electronic order for ceftaroline or daptomycin as frst-line therapy within 14 days of admission. Baseline characteristics were compared using Chi-square, Fisher\u27s exact, and Wilcoxon rank-sum tests. Hospital readmission and patient mortality proportions were compared through multivariable logistic regression models with Hispanic ethnicity, prior hospitalization, dyslipidemia, and Charlson comorbidity score as covariates. Results In total, 223 patients were included (ceftaroline, n = 71; daptomycin n = 152). At baseline, ceftaroline patients were more likely to be Hispanic (18 vs. 6%, p \u3c 0.01) and have been hospitalized in the past 90 days (34 vs. 19%, p = 0.02). Unadjusted 90-day hospital readmission proportions for ceftaroline versus daptomycin were 34 vs. 49%, and unadjusted 90-day mortality proportions were 1% vs. 8%. In multivariable models, ceftaroline patients were less likely to experience 90-day hospital readmission (odds ratio [OR] 0.46, 95% confdence interval [CI] 0.25–0.85) and 90-day mortality (OR 0.14, 95% CI 0.01–0.77). Conclusions In this population, ceftaroline was associated with lower 90-day hospital readmission and 90-day mortality compared with daptomycin when used as frst-line therapy for DFI

The enigmatic core L1451-mm: a first hydrostatic core? or a hidden VeLLO?

We present the detection of a dust continuum source at 3-mm (CARMA) and 1.3-mm (SMA), and 12CO(2-1) emission (SMA) towards the L1451-mm dense core. These detections suggest a compact object and an outflow where no point source at mid-infrared wavelengths is detected using Spitzer. An upper limit for the dense core bolometric luminosity of 0.05 Lsun is obtained. By modeling the broadband SED and the continuum interferometric visibilities simultaneously, we confirm that a central source of heating is needed to explain the observations. This modeling also shows that the data can be well fitted by a dense core with a YSO and disk, or by a dense core with a central First Hydrostatic Core (FHSC). Unfortunately, we are not able to decide between these two models, which produce similar fits. We also detect 12CO(2-1) emission with red- and blue-shifted emission suggesting the presence of a slow and poorly collimated outflow, in opposition to what is usually found towards young stellar objects but in agreement with prediction from simulations of a FHSC. This presents the best candidate, so far, for a FHSC, an object that has been identified in simulations of collapsing dense cores. Whatever the true nature of the central object in L1451-mm, this core presents an excellent laboratory to study the earliest phases of low-mass star formation.Comment: 15 pages, 9 figures, emulateapj. Accepted by Ap

The Green Bank Ammonia Survey (GAS): First Results of NH3 mapping the Gould Belt

We present an overview of the first data release (DR1) and first-look science from the Green Bank Ammonia Survey (GAS). GAS is a Large Program at the Green Bank Telescope to map all Gould Belt star-forming regions with $A_V \gtrsim 7$ mag visible from the northern hemisphere in emission from NH$_3$ and other key molecular tracers. This first release includes the data for four regions in Gould Belt clouds: B18 in Taurus, NGC 1333 in Perseus, L1688 in Ophiuchus, and Orion A North in Orion. We compare the NH$_3$ emission to dust continuum emission from Herschel, and find that the two tracers correspond closely. NH$_3$ is present in over 60\% of lines-of-sight with $A_V \gtrsim 7$ mag in three of the four DR1 regions, in agreement with expectations from previous observations. The sole exception is B18, where NH$_3$ is detected toward ~ 40\% of lines-of-sight with $A_V \gtrsim 7$ mag. Moreover, we find that the NH$_3$ emission is generally extended beyond the typical 0.1 pc length scales of dense cores. We produce maps of the gas kinematics, temperature, and NH$_3$ column densities through forward modeling of the hyperfine structure of the NH$_3$ (1,1) and (2,2) lines. We show that the NH$_3$ velocity dispersion, ${\sigma}_v$, and gas kinetic temperature, $T_K$, vary systematically between the regions included in this release, with an increase in both the mean value and spread of ${\sigma}_v$ and $T_K$ with increasing star formation activity. The data presented in this paper are publicly available.Comment: 33 pages, 27 figures, accepted to ApJS. Datasets are publicly available: https://dataverse.harvard.edu/dataverse/GAS_DR