Ulnar Collateral Ligament Reconstruction with Traditional Docking Compared to Novel Surgical Techniques

Background: Ulnar Collateral Ligament Reconstruction (UCLR) is a surgical procedure on one of the main ligaments that provides normal stability for the elbow joint against excessive valgus stress. Damage to this ligament is common in athletes performing overhead throwing activities, primarily baseball players, due to excessive valgus stress during the throwing motion. The most common form of treatment for this type of injury is reconstructive surgery of the ligament, especially if athletes wish to return to sport participation. This type of surgery is extremely invasive and requires extensive post-operative rehabilitation in order to facilitate return to play. To date, many surgical techniques have been proposed and evaluated, but there are no conclusive comparison studies on patient outcomes following UCLR. Purpose: The purpose of this paper is to analyze previous studies on UCLR techniques and determine if there is a single superior surgical method leading to improved biomechanical outcomes and decreased failure measures. Our focused clinical question was identifying if the traditional docking technique compared to novel docking techniques during UCLR superior in relation to biomechanical outcomes and failure measures in cadaveric tissue. Methodology: The study design in this paper is a critically appraised topic. Various scholarly databases such as PubMed, MEDLINE and SportDiscus were utilized to search for studies related to UCLR surgical techniques. After an initial search, a list of fifteen relevant studies were identified. Each study was then scrutinized and evaluated to meet predetermined inclusion criteria and a minimum score of 6/9 on the PEDro scale. All studies not meeting these requirements were excluded. This left a total of five articles which were then used to answer the clinical question for this paper. The inclusion criteria involved meeting a cadaveric age of 16-60 y, objective measures of valgus testing, angular displacement, stiffness and modes of failure as post-operative outcomes. Further, we included studies that had a minimum of seven cadaver pairs tested, and studies were required to compare traditional docking to at least one novel technique. Results: All five studies involved compared at least one novel surgical technique to the docking technique. Four studies found no significant overall difference between the native and reconstructed states of any surgical technique. One study found no overall significant difference, but did identify slight differences in biomechanical properties. Discussion: All conclusions from individual studies demonstrate comparable findings between all UCLR techniques. Biomechanics, kinematics and failure modes in the acute stages following surgery in cadavers are similar between UCLR techniques. Despite all that has been done, additional research is still necessary to determine a superior surgical technique

A general approach to quantum dynamics using a variational master equation: Application to phonon-damped Rabi rotations in quantum dots

We develop a versatile master equation approach to describe the non-equilibrium dynamics of a two-level system in contact with a bosonic environment, which allows for the exploration of a wide range of parameter regimes within a single formalism. As an experimentally relevant example, we apply this technique to the study of excitonic Rabi rotations in a driven quantum dot, and compare its predictions to the numerical Feynman integral approach. We find excellent agreement between the two methods across a generally difficult range of parameters. In particular, the variational master equation technique captures effects usually considered to be non-perturbative, such as multi-phonon processes and bath-induced driving renormalisation, and can give reliable results even in regimes in which previous master equation approaches fail.Comment: 5 pages, 2 figures. Published version, revised title, minor changes to the tex

A multi-site variational master equation approach to dissipative energy transfer

Unitary transformations can allow one to study open quantum systems in situations for which standard, weak-coupling type approximations are not valid. We develop here an extension of the variational (polaron) transformation approach to open system dynamics, which applies to arbitrarily large exciton transport networks with local environments. After deriving a time-local master equation in the transformed frame, we go on to compare the population dynamics predicted using our technique with other established master equations. The variational frame dynamics are found to agree with both weak coupling and full polaron master equations in their respective regions of validity. In parameter regimes considered difficult for these methods, the dynamics predicted by our technique are found to interpolate between the two. The variational method thus gives insight, across a broad range of parameters, into the competition between coherent and incoherent processes in determining the dynamical behaviour of energy transfer networks.Peer reviewe

Mitigating radiation damage of single photon detectors for space applications

Single-photon detectors in space must retain useful performance characteristics despite being bombarded with sub-atomic particles. Mitigating the effects of this space radiation is vital to enabling new space applications which require high-fidelity single-photon detection. To this end, we conducted proton radiation tests of various models of avalanche photodiodes (APDs) and one model of photomultiplier tube potentially suitable for satellite-based quantum communications. The samples were irradiated with 106 MeV protons at doses approximately equivalent to lifetimes of 0.6 , 6, 12 and 24 months in a low-Earth polar orbit. Although most detection properties were preserved, including efficiency, timing jitter and afterpulsing probability, all APD samples demonstrated significant increases in dark count rate (DCR) due to radiation-induced damage, many orders of magnitude higher than the 200 counts per second (cps) required for ground-to-satellite quantum communications. We then successfully demonstrated the mitigation of this DCR degradation through the use of deep cooling, to as low as -86 degrees C. This achieved DCR below the required 200 cps over the 24 months orbit duration. DCR was further reduced by thermal annealing at temperatures of +50 to +100 degrees C.Comment: The license has been corrected. Note that the license of v2 was incorrect and not valid. No other changes since v

Prenatal Lead Exposure Risk Assessment by Vermont Maternity Care Providers

Introduction. One percent of women of childbearing age in the U.S. have blood lead levels ≥ 5 ug/dL, which are associated with maternal hypertension during pregnancy, neural tube and cardiac defects in infants, low birth weight, prematurity, and spontaneous abortion. It is unknown whether obstetrics providers in Vermont are screening their pregnant patients for lead levels and educating them on lead exposure risks. Objective. To gain an understanding of current lead screening practices in Vermont and issue recommendations for disseminating lead screening information. Methods. We developed and e-mailed a survey to practicing OB/GYN physicians, maternity care focused family medicine physicians, nurse midwives, and professional midwives. The survey assessed current screening practices for lead exposure in their pregnant patients, interest in receiving statewide guidelines, and guideline dissemination preferences. Results. Of the 41 respondents, 12% currently conduct risk assessments for lead exposure with all of their pregnant patients. Fifty four percent of maternity providers give all of their patients educational materials about lead exposure and risk of toxicity. Seventy one percent of maternity providers think that having guidelines provided by the Vermont Department of Health would encourage them to begin or continue lead exposure screening. The two preferred methods of communicating guidelines to physicians were grand rounds and email whereas non-physician providers preferred email and webinar. Discussion. The majority of pregnant patients in Vermont are not properly assessed or educated about lead risks. However, there is interest in having statewide standardized lead risk assessment guidelines, with dissemination preferences differing by provider type.https://scholarworks.uvm.edu/comphp_gallery/1248/thumbnail.jp

Quantifying the Uncertainties of a Bottom-Up Emission Inventory of Anthropogenic Atmospheric Pollutants in China

The uncertainties of a national, bottom-up inventory of Chinese emissions of anthropogenic $SO_2$, $NO_x$, and particulate matter (PM) of different size classes and carbonaceous species are comprehensively quantified, for the first time, using Monte Carlo simulation. The inventory is structured by seven dominant sectors: coal-fired electric power, cement, iron and steel, other industry (boiler combustion), other industry (non-combustion processes), transportation, and residential. For each parameter related to emission factors or activity-level calculations, the uncertainties, represented as probability distributions, are either statistically fitted using results of domestic field tests or, when these are lacking, estimated based on foreign or other domestic data. The uncertainties (i.e., 95% confidence intervals around the central estimates) of Chinese emissions of $SO_2$, $NO_x$, total PM, $PM_{10}$, $PM_{2.5}$, black carbon (BC), and organic carbon (OC) in 2005 are estimated to be −14%~13%, −13%~37%, −11%~38%, −14%~45%, −17%~54%, −25%~136%, and −40%~121%, respectively. Variations at activity levels (e.g., energy consumption or industrial production) are not the main source of emission uncertainties. Due to narrow classification of source types, large sample sizes, and relatively high data quality, the coal-fired power sector is estimated to have the smallest emission uncertainties for all species except BC and OC. Due to poorer source classifications and a wider range of estimated emission factors, considerable uncertainties of $NO_x$ and PM emissions from cement production and boiler combustion in other industries are found. The probability distributions of emission factors for biomass burning, the largest source of BC and OC, are fitted based on very limited domestic field measurements, and special caution should thus be taken interpreting these emission uncertainties. Although Monte Carlo simulation yields narrowed estimates of uncertainties compared to previous bottom-up emission studies, the results are not always consistent with those derived from satellite observations. The results thus represent an incremental research advance; while the analysis provides current estimates of uncertainty to researchers investigating Chinese and global atmospheric transport and chemistry, it also identifies specific needs in data collection and analysis to improve on them. Strengthened quantification of emissions of the included species and other, closely associated ones – notably $CO_2$, generated largely by the same processes and thus subject to many of the same parameter uncertainties – is essential not only for science but for the design of policies to redress critical atmospheric environmental hazards at local, regional, and global scales.Engineering and Applied Science

Solar-like oscillations in the G2 subgiant beta Hydri from dual-site observations

We have observed oscillations in the nearby G2 subgiant star beta Hyi using high-precision velocity observations obtained over more than a week with the HARPS and UCLES spectrographs. The oscillation frequencies show a regular comb structure, as expected for solar-like oscillations, but with several l=1 modes being strongly affected by avoided crossings. The data, combined with those we obtained five years earlier, allow us to identify 28 oscillation modes. By scaling the large frequency separation from the Sun, we measure the mean density of beta Hyi to an accuracy of 0.6%. The amplitudes of the oscillations are about 2.5 times solar and the mode lifetime is 2.3 d. A detailed comparison of the mixed l=1 modes with theoretical models should allow a precise estimate of the age of the star.Comment: 13 pages, 14 figures, accepted by ApJ. Fixed minor typo (ref to Fig 14