Clinical Report: Land-Based Versus Pool-Based Exercise for People Awaiting Joint Replacement Surgery of the Hip or Knee: Results of a Randomized Controlled Trial

Background: Individuals with either knee or hip osteoarthritis are at risk of experiencing pain and developing functional limitations (Bennell 2005). In many cases, to alleviate pain and improve one\u27s quality of life, an individual may require a total joint replacement. Despite advances in surgical technique and joint replacement hardware, surgical procedures are not without risk. Conservative treatments, including therapeutic exercise programmes, may improve a patient\u27s status while avoiding the potential risks associated with surgery (pain, medication utilisation, long bouts of rehabilitation, and/ or death). Researchers have demonstrated that some patients may experience improvements in pain and functional abilities after participating in either land-based or aquatic-based exercise programmes (Maurer et al 1999, Hinman et al 2007). However, according to Gill et al (2009), there is paucity of literature addressing post-exercise outcomes in individuals who are scheduled for either hip or knee joint replacement surgery. Aim: To assess self-reported and performance-based functional measures in individuals (who were scheduled to have either a hip or knee joint replacement) after the completion of either a land-based or pool-based exercise programme. Methods: The authors implemented a randomised controlled trial, allocating subjects to either the land-based (n=40) or pool-based (n=42) exercise programme, stratified by the involved joint. Subjects were recruited from a waiting list of patients who were scheduled for either a knee replacement or hip replacement. Each exercise session was performed for one hour over a total period of 12 sessions (2 times a week for 6 weeks). In addition, the authors instructed the subjects to exercise 3 days a week at home (for 30 minutes each session) performing a combination of walking, stationary bicycling, and/or other exercises they performed in class. Self-reported function (as measured by Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), performance-based outcomes (50-foot timed walk and 30-second chair stand test), and psychosocial status (SF-36 MCS) measures were collected prior to treatment, at the end of the 6-week training session, and finally two months later. These data were collected by a blinded assessor. Additionally, daily pre- and post-exercise pain levels were recorded during each session. Results: The authors reported that both pool-based and land-based exercise programmes were effective in reducing pain and increasing function in patients with a diagnosis of either knee or hip arthritis. However, there were no differences between groups for WOMAC pain (p = .614), WOMAC function (p = .739), 50-foot timed walk test p = .173), the 30-second chair stand test (p = .179), or the SF-36 MCS (p = .205). Those who participated in the land-based programme experienced improvements in pain at both assessment periods (p = .000; .015) whereas the participants in the pool-based programme only demonstrated improvements at the first assessment (p = .011; .431). Both groups demonstrated significant functional improvements at the first testing session for performance-based tests as well as demonstrating significant improvement in WOMAC function scores and the 30-second chair stand test at the final assessment session. Those who participated in the pool-based programme experienced a significantly lower daily pain score (p = .005) when compared to those in the land-based programme. Conclusion: The authors report that both training programmes may lead to positive functional outcomes in individuals who are awaiting a joint replacement surgery. In addition, the authors report that those who participated in the pool programme may tolerate the treatment with less post-exercise pain

A Study of the Residual 39Ar Content in Argon from Underground Sources

The discovery of argon from underground sources with significantly less 39Ar than atmospheric argon was an important step in the development of direct-detection dark matter experiments using argon as the active target. We report on the design and operation of a low background detector with a single phase liquid argon target that was built to study the 39Ar content of the underground argon. Underground argon from the Kinder Morgan CO2 plant in Cortez, Colorado was determined to have less than 0.65% of the 39Ar activity in atmospheric argon.Comment: 21 pages, 10 figure

A New Method of Measuring 81Kr and 85Kr Abundances in Environmental Samples

We demonstrate a new method for determining the 81Kr/Kr ratio in environmental samples based upon two measurements: the 85Kr/81Kr ratio measured by Atom Trap Trace Analysis (ATTA) and the 85Kr/Kr ratio measured by Low-Level Counting (LLC). This method can be used to determine the mean residence time of groundwater in the range of 10^5 - 10^6 a. It requires a sample of 100 micro-l STP of Kr extracted from approximately two tons of water. With modern atmospheric Kr samples, we demonstrate that the ratios measured by ATTA and LLC are directly proportional to each other within the measurement error of +/- 10%; we calibrate the 81Kr/Kr ratio of modern air measured using this method; and we show that the 81Kr/Kr ratios of samples extracted from air before and after the development of the nuclear industry are identical within the measurement error

A Slope-Based Method for Least Cost Tolerance Allocation

In this paper, a new methodology is presented to solve the tolerance allocation-process selection problem simultaneously The prob lem is modeled using discrete and continuous variables and is transformed into a model with only continuous variables by defining an efficient tolerance-cost curve for each component Since the efficient tolerance-cost curve is neither convex nor concave, nonlinear programming method ologies cannot be directly applied The tolerance-cost curve is piecewise linearly approximated and an efficient methodology is developed to solve the problem The method starts with a solution which minimizes the objective function value but is not feasible The infeasibility is iteratively reduced in a way that the increase in the objective function value is minimal Computational analysis indicates that the method is very robust and requires negligible CPU timeYeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Rapid processing of ⁸⁵5 Kr/Kr ratios using Atom Trap Trace Analysis

We report a methodology for measuring ⁸⁵ Kr/Kr isotopic abundances using Atom Trap Trace Analysis (ATTA) that increases sample measurement throughput by over an order of magnitude to six samples per 24 h. The noble gas isotope ⁸⁵ Kr (half-life 510.7 years) is a useful tracer for young groundwater in the age range of 5–50 years. ATTA, an efficient and selective laser-based atom counting method, has recently been applied to ⁸⁵ Kr/Kr isotopic abundance measurements, requiring 5–10 μL of krypton gas at STP extracted from 50 to 100 L of water. Previously, a single such measurement required 48 h. Our new method demonstrates that we can measure 85Kr/Kr ratios with 3–5% relative uncertainty every 4 h, on average, with the same sample requirements

Discovery of underground argon with low level of radioactive 39Ar and possible applications to WIMP dark matter detectors

We report on the first measurement of 39Ar in argon from underground natural gas reservoirs. The gas stored in the US National Helium Reserve was found to contain a low level of 39Ar. The ratio of 39Ar to stable argon was found to be <=4x10-17 (84% C.L.), less than 5% the value in atmospheric argon (39Ar/Ar=8x10-16). The total quantity of argon currently stored in the National Helium Reserve is estimated at 1000 tons. 39Ar represents one of the most important backgrounds in argon detectors for WIMP dark matter searches. The findings reported demonstrate the possibility of constructing large multi-ton argon detectors with low radioactivity suitable for WIMP dark matter searches.Comment: 6 pages, 2 figures, 2 table

Measurement of the specific activity of Ar-39 in natural argon

We report on the measurement of the specific activity of Ar-39 in natural argon. The measurement was performed with a 2.3-liter two-phase (liquid and gas) argon drift chamber. The detector was developed by the WARP Collaboration as a prototype detector for WIMP Dark Matter searches with argon as a target. The detector was operated for more than two years at Laboratori Nazionali del Gran Sasso, Italy, at a depth of 3,400 m w.e. The specific activity measured for Ar-39 is 1.01 +/- 0.02(stat) +/- 0.08(syst) Bq per kg of natural Ar.Comment: 11 pages, 6 figures, to be submitted to Nucl. Instrum. Methods

Measurement of the scintillation time spectra and pulse-shape discrimination of low-energy beta and nuclear recoils in liquid argon with DEAP-1

The DEAP-1 low-background liquid argon detector was used to measure scintillation pulse shapes of electron and nuclear recoil events and to demonstrate the feasibility of pulse-shape discrimination (PSD) down to an electron-equivalent energy of 20 keV. In the surface dataset using a triple-coincidence tag we found the fraction of beta events that are misidentified as nuclear recoils to be $<1.4\times 10^{-7}$ (90% C.L.) for energies between 43-86 keVee and for a nuclear recoil acceptance of at least 90%, with 4% systematic uncertainty on the absolute energy scale. The discrimination measurement on surface was limited by nuclear recoils induced by cosmic-ray generated neutrons. This was improved by moving the detector to the SNOLAB underground laboratory, where the reduced background rate allowed the same measurement with only a double-coincidence tag. The combined data set contains $1.23\times10^8$ events. One of those, in the underground data set, is in the nuclear-recoil region of interest. Taking into account the expected background of 0.48 events coming from random pileup, the resulting upper limit on the electronic recoil contamination is $<2.7\times10^{-8}$ (90% C.L.) between 44-89 keVee and for a nuclear recoil acceptance of at least 90%, with 6% systematic uncertainty on the absolute energy scale. We developed a general mathematical framework to describe PSD parameter distributions and used it to build an analytical model of the distributions observed in DEAP-1. Using this model, we project a misidentification fraction of approx. $10^{-10}$ for an electron-equivalent energy threshold of 15 keV for a detector with 8 PE/keVee light yield. This reduction enables a search for spin-independent scattering of WIMPs from 1000 kg of liquid argon with a WIMP-nucleon cross-section sensitivity of $10^{-46}$ cm$^2$, assuming negligible contribution from nuclear recoil backgrounds.Comment: Accepted for publication in Astroparticle Physic

Simulation of cell-substrate traction force dynamics in response to soluble factors

Finite element (FE) simulations of contractile responses of vascular muscular thin films (vMTFs) and endothelial cells resting on an array of micro-posts under stimulation of soluble factors were conducted in comparison with experimental measurements reported in literature. Two types of constitutive models were employed in the simulations, i.e. smooth muscle cell type and non-smooth muscle cell type. The time histories of the effects of soluble factors were obtained via calibration against experimental measurements of contractile responses of tissues or cells. The numerical results for vMTFs with micropatterned tissues suggest that the radius of curvature of vMTFs under stimulation of soluble factors is sensitive to width of the micropatterned tissue, i.e. the radius of curvature increases as the tissue width decreases. However, as the tissue response is essentially isometric, the time history of the maximum principal stress of the micropatterned tissues is not sensitive to tissue width. Good agreement has been achieved for predictions of the vasoconstrictor endothelin-1 (ET-1) induced contraction stress between the FE numerical simulation and the experiment based approach of Alford, et al. (2011) for the vMTFs with 40, 60, 80 and 100 μm width patterns. This may suggest the contraction stress is weakly sensitive to the tissue width for these patterns. However, for 20 μm width tissue patterning, the numerical simulation result for contraction stress is less than the average value of experimental measurements, which may suggest the thinner and more elongated spindle-like cells within the 20 μm width tissue patterning have higher contractile output. The constitutive model for non-smooth muscle cells was used to simulate the contractile response of the endothelial cells. The substrate was treated as an effective continuum. For agonists such as Lysophosphatidic acid (LPA) and vascular endothelial growth factor (VEGF), the deformation of the cell diminishes from edge to centre and the central part of the cell is essentially under isometric state. Numerical studies demonstrated the scenarios that cell polarity can be triggered via manipulation of the effective stiffness and Possion’s ratio of the substrate

HIV-1 drug resistance in people on dolutegravir-based antiretroviral therapy:a collaborative cohort analysis

BACKGROUND The widespread use of the integrase strand transfer inhibitor (INSTI) dolutegravir in first-line and second-line antiretroviral therapy (ART) might facilitate emerging resistance. The DTG RESIST study combined data from HIV cohorts to examine patterns of drug resistance mutations (DRMs) and identify risk factors for dolutegravir resistance. METHODS We included cohorts with INSTI resistance data from two collaborations (ART Cohort Collaboration, International epidemiology Databases to Evaluate AIDS in Southern Africa), and the UK Collaborative HIV Cohort. Eight cohorts from Canada, France, Germany, Italy, the Netherlands, Switzerland, South Africa, and the UK contributed data on individuals who were viraemic on dolutegravir-based ART and underwent genotypic resistance testing. Individuals with unknown dolutegravir initiation date were excluded. Resistance levels were categorised using the Stanford algorithm. We identified risk factors for resistance using mixed-effects ordinal logistic regression models. FINDINGS We included 599 people with genotypic resistance testing on dolutegravir-based ART between May 22, 2013, and Dec 20, 2021. Most had HIV-1 subtype B (n=351, 59%), a third had been exposed to first-generation INSTIs (n=193, 32%), 70 (12%) were on dolutegravir dual therapy, and 18 (3%) were on dolutegravir monotherapy. INSTI DRMs were detected in 86 (14%) individuals; 20 (3%) had more than one mutation. Most (n=563, 94%) were susceptible to dolutegravir, seven (1%) had potential low, six (1%) low, 17 (3%) intermediate, and six (1%) high-level dolutegravir resistance. The risk of dolutegravir resistance was higher on dolutegravir monotherapy (adjusted odds ratio [aOR] 34·1, 95% CI 9·93-117) and dolutegravir plus lamivudine dual therapy (aOR 9·21, 2·20-38·6) compared with combination ART, and in the presence of potential low or low (aOR 5·23, 1·32-20·7) or intermediate or high-level (aOR 13·4, 4·55-39·7) nucleoside reverse transcriptase inhibitor (NRTI) resistance. INTERPRETATION Among people with viraemia on dolutegravir-based ART, INSTI DRMs and dolutegravir resistance were rare. NRTI resistance substantially increased the risk of dolutegravir resistance, which is of concern, notably in resource-limited settings. Monitoring is important to prevent resistance at the individual and population level and ensure the long-term sustainability of ART. FUNDING US National Institutes of Health, Swiss National Science Foundation