Optimization of an Electromagnetic Energy Harvesting Device

This paper presents the modeling and optimization of an electromagnetic-based generator for generating power from ambient vibrations. Basic equations describing such generators are presented and the conditions for maximum power generation are described. Two-centimeter scale prototype generators, which consist of magnets suspended on a beam vibrating relative to a coil, have been built and tested. The measured power and modeled results are compared. It is shown that the experimental results confirm the optimization theory

Superconductivity and local non-centrosymmetricity in crystal lattices

Symmetry of the crystal lattice can be a determining factor for the structure of Cooper pairs in unconventional superconductors. In this study we extend the discussion of superconductivity in non-centrosymmetric materials to the case when inversion symmetry is missing locally, but is present on a global level. Concretely, we investigate the staggered non-centrosymmetricity within a regular sublattice structure, in some analogy to the discussion of superconductivity in antiferromagnetic systems. Three crystal structures are analyzed in detail as illustrative examples for the extended classification of Cooper-pairing channels. One of the cases may be relevant for the class of iron-pnictide superconductors

Disorder Induced Stripes in d-Wave Superconductors

Stripe phases are observed experimentally in several copper-based high-Tc superconductors near 1/8 hole doping. However, the specific characteristics may vary depending on the degree of dopant disorder and the presence or absence of a low- temperature tetragonal phase. On the basis of a Hartree-Fock decoupling scheme for the t-J model we discuss the diverse behavior of stripe phases. In particular the effect of inhomogeneities is investigated in two distinctly different parameter regimes which are characterized by the strength of the interaction. We observe that small concen- trations of impurities or vortices pin the unidirectional density waves, and dopant disorder is capable to stabilize a stripe phase in parameter regimes where homogeneous phases are typically favored in clean systems. The momentum-space results exhibit universal features for all coexisting density-wave solutions, nearly unchanged even in strongly disordered systems. These coexisting solutions feature generically a full energy gap and a particle-hole asymmetry in the density of states.Comment: 28 pages, 8 figure

Iatrogenic Peroneal Nerve Palsy Rates Secondary to Open Reduction Internal Fixation for Tibial Plateau Fractures Using an Intraoperative Distractor

Objective: To report the rate of peroneal nerve palsy after routine use of intraoperative distraction during open reduction internal fixation (ORIF) for lateral unicondylar and bicondylar tibial plateau fracture (TPF) repairs. Design: Retrospective chart review Setting: Level I trauma center Patients: Patients with traumatic TPF treated with ORIF between 2007 and 2017 Intervention: ORIF for lateral unicondylar and bicondylar TPF. Main Outcome Measurement: Presence and resolution of neurovascular injury Results: There were a total of 21 lateral unicondylar and 40 bicondylar TPFs repaired via ORIF in 60 patients identified during the study period with one year follow up and complete records for review. Thirty-six patients had staged external fixation prior to ORIF while 24 were treated with ORIF initially. Of the staged patients, 9 of 36 (25%) developed nerve palsy while those undergoing initial ORIF (not staged) developed palsy in only one case (1 of 24, or 4%). Of the patients who developed nerve palsy 9 of 10 (90%) were staged with an initial external fixator prior to ORIF. The incidence of iatrogenic peroneal nerve palsy secondary to intraoperative distraction was 16.4% (10 of 61). Only 60% (6 of 10) of peroneal nerve palsies recovered clinically with a mean recovery time of approximately 14 weeks. Comparison of demographics in patients with peroneal nerve palsy versus those without yielded no significant difference by sex (p = 0.08), age (p =0.27), fracture type (p = 0.29), tobacco use (p = 0.44) or alcohol use (p = 0.78). Conclusions: Peroneal nerve palsy is a common sequela of ORIF for TPFs involving the lateral compartment utilizing an intraoperative distractor. Staged external fixation followed by definitive ORIF using intra-operative distraction, was associated with significant risk for developing nerve palsy (9/10). Many patients (40%) who develop peroneal nerve palsies do not recover, leading to permanent loss of motor and/or sensory function for 7% of patients studied. None of the epidemiologic variables evaluated yielded predictive value for development of peroneal nerve palsy or subsequent resolution. Caution should be exercised in avoiding over distraction when using intraoperative distraction, especially in those cases that had staged fixation, most notably bicondylar injuries

Bridging the Expertise of Advocates and Academics to Identify Reproductive Justice Learning Outcomes

Phenomenon: Reproductive justice (RJ) is defined by women of color advocates as the right to have children, not have children and parent children while maintaining reproductive autonomy. In the United States, physicians have been complicit in multiple historical reproductive injustices, involving coercive sterilization of thousands of people of color, low income, and disabilities. Currently, reproductive injustices continue to occur; however, physicians have no formal RJ medical education to address injustices. The objective of this study was to engage leading advocates within the movement using a Delphi method to identify critical components for such a curriculum. Approach: In 2016, we invited 65 RJ advocates and leaders to participate in an expert panel to design RJ medical education. A 3-round Delphi survey was distributed electronically to identify content for inclusion in an RJ curriculum. In the next 2 survey rounds, experts offered feedback and revisions and rated agreement with including content recommendations in the final curriculum. We calculated descriptive statistics to analyze quantitative data. A team with educational expertise wrote learning outcomes based on expert content recommendations. Findings: Of the 65 RJ advocates and leaders invited, 41 participated on the expert panel of the Delphi survey. In the first survey, the expert panel recommended 58 RJ content areas through open-ended response. Over the next 2 rounds, there was consensus among the panel to include 52 of 58 of these areas in the curriculum. Recommended content fell into 11 broad domains: access, disparities, and structural competency; advocacy; approaches to reproductive healthcare; contemporary law and policy; cultural safety; historical injustices; lesbian, gay, bisexual, transgender, queer/questioning, and intersex health; oppression, power, and bias training; patient care; reproductive health; and RJ definitions. The 97 learning outcomes created from this process represented both unique and existing educational elements. Insights: A collaborative methodology infused with RJ values can bridge experts in advocacy and academics. New learning outcomes identified through this process can enhance medical education; however, it is just as important to consider education in RJ approaches to care as it is knowledge about that care. We must explore the pedagogic process of RJ medical education while considering that expertise in this area may exist outside of the medical community and thus there is a need to partner with RJ advocates. Finally, we expect to use innovative teaching methods to transform medical education and achieve an RJ focus

Consolidated health economic evaluation reporting standards (CHEERS) statement

<p>Economic evaluations of health interventions pose a particular challenge for reporting. There is also a need to consolidate and update existing guidelines and promote their use in a user friendly manner. The Consolidated Health Economic Evaluation Reporting Standards (CHEERS) statement is an attempt to consolidate and update previous health economic evaluation guidelines efforts into one current, useful reporting guidance. The primary audiences for the CHEERS statement are researchers reporting economic evaluations and the editors and peer reviewers assessing them for publication.</p> <p>The need for new reporting guidance was identified by a survey of medical editors. A list of possible items based on a systematic review was created. A two round, modified Delphi panel consisting of representatives from academia, clinical practice, industry, government, and the editorial community was conducted. Out of 44 candidate items, 24 items and accompanying recommendations were developed. The recommendations are contained in a user friendly, 24 item checklist. A copy of the statement, accompanying checklist, and this report can be found on the ISPOR Health Economic Evaluations Publication Guidelines Task Force website (www.ispor.org/TaskForces/EconomicPubGuidelines.asp).</p> <p>We hope CHEERS will lead to better reporting, and ultimately, better health decisions. To facilitate dissemination and uptake, the CHEERS statement is being co-published across 10 health economics and medical journals. We encourage other journals and groups, to endorse CHEERS. The author team plans to review the checklist for an update in five years.</p&gt

Automatic determination of Greulich and Pyle bone age in healthy Dutch children

Background: Bone age (BA) assessment is a routine procedure in paediatric radiology, for which the Greulich and Pyle (GP) atlas is mostly used. There is rater variability, but the advent of automatic BA determination eliminates this. Objective: To validate the BoneXpert method for automatic determination of skeletal maturity of healthy children against manual GP BA ratings. Materials and methods: Two observers determined GP BA with knowledge of the chronological age (CA). A total of 226 boys with a BA of 3-17 years and 179 girls with a BA of 3-15 years were included in the study. BoneXpert's estimate of GP BA was calibrated to agree on average with the manual ratings based on several studies, including the present study. Results: Seven subjects showed a deviation between manual and automatic BA in excess of 1.9 years. They were re-rated blindly by two raters. After correcting these seven ratings, the root mean square error between manual and automatic rating in the 405 subjects was 0.71 years (range 0.66-0.76 years, 95% CI). BoneXpert's GP BA is on average 0.28 and 0.20 years behind the CA for boys and girls, respectively. Conclusion: BoneXpert is a robust method for automatic determination of BA

Cost-Effectiveness of Haemorrhoidal Artery Ligation versus Rubber Band Ligation for the Treatment of Grade II–III Haemorrhoids: Analysis Using Evidence from the HubBLe Trial

Aim Haemorrhoids are a common condition, with nearly 30,000 procedures carried out in England in 2014/15, and result in a significant quality-of-life burden to patients and a financial burden to the healthcare system. This study examined the cost effectiveness of haemorrhoidal artery ligation (HAL) compared with rubber band ligation (RBL) in the treatment of grade II–III haemorrhoids. Method This analyses used data from the HubBLe study, a multicentre, open-label, parallel group, randomised controlled trial conducted in 17 acute UK hospitals between September 2012 and August 2015. A full economic evaluation, including long-term cost effectiveness, was conducted from the UK National Health Service (NHS) perspective. Main outcomes included healthcare costs, quality-adjusted life-years (QALYs) and recurrence. Costeffectiveness results were presented in terms of incremental cost per QALY gained and cost per recurrence avoided. Extrapolation analysis for 3 years beyond the trial follow-up, two subgroup analyses (by grade of haemorrhoids and recurrence following RBL at baseline), and various sensitivity analyses were undertaken. Results In the primary base-case within-trial analysis, the incremental total mean cost per patient for HAL compared with RBL was £1027 (95% confidence interval [CI] £782– £1272, p\0.001). The incremental QALYs were 0.01 QALYs (95% CI -0.02 to 0.04, p = 0.49). This generated an incremental cost-effectiveness ratio (ICER) of £104,427 per QALY. In the extrapolation analysis, the estimated probabilistic ICER was £21,798 per QALY. Results from all subgroup and sensitivity analyses did not materially change the base-case result. Conclusions Under all assessed scenarios, the HAL procedure was not cost effective compared with RBL for the treatment of grade II-III haemorrhoids at a cost-effectiveness threshold of £20,000 per QALY; therefore