8,268 research outputs found
Characterization of Alkali Metal Dispensers and Non-Evaporable Getter Pumps in Ultra-High Vacuum Systems for Cold Atomic Sensors
A glass ultrahigh vacuum chamber with rubidium alkali metal dispensers and
non-evaporable getter pumps has been developed and used to create a cold atomic
sample in a chamber that operates with only passive vacuum pumps. The ion-mass
spectrum of evaporated gases from the alkali metal dispenser has been recorded
as a function of dispenser current. The efficacy of the non-evaporable getter
pumps in promoting and maintaining vacuum has been characterized by observation
of the Rb vapor optical absorption on the D2 transition at 780 nm and vacuum
chamber pressure rate of rise tests. We have demonstrated a sample of
laser-cooled Rb atoms in this chamber when isolated and operating without
active vacuum pumps
Return to Sport and Athletic Function in an Active Population After Primary Arthroscopic Labral Reconstruction of the Hip
Background: Labral reconstruction has been advocated as an alternative to debridement for the treatment of irreparable labral tears, showing favorable short-term results. However, literature is scarce regarding outcomes and return to sport in the nonelite athletic population.
Purpose: To report minimum 1-year clinical outcomes and the rate of return to sport in athletic patients who underwent primary hip arthroscopy with labral reconstruction in the setting of femoroacetabular impingement syndrome and irreparable labral tears.
Study Design: Case series; Level of evidence, 4.
Methods: Data were prospectively collected and retrospectively analyzed for patients who underwent an arthroscopic labral reconstruction between August 2012 and December 2017. Patients were included if they identified as an athlete (high school, college, recreational, or amateur); had follow-up on the following patient-reported outcomes (PROs): modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), Hip Outcome Score–Sport Specific Subscale (HOS-SSS), and visual analog scale (VAS); and completed a return-to-sport survey at 1 year postoperatively. Patients were excluded if they underwent any previous ipsilateral hip surgery, had dysplasia, or had prior hip conditions. The proportions of patients who achieved the minimal clinically important difference (MCID) and patient acceptable symptomatic state (PASS) for mHHS and HOS-SSS were calculated. Statistical significance was set at P =.05.
Results: There were 32 (14 females) athletes who underwent primary arthroscopic labral reconstruction during the study period. The mean age and body mass index of the group were 40.3 years (range, 15.5-58.7 years) and 27.9 kg/m2 (range, 19.6-40.1 kg/m2), respectively. The mean follow-up was 26.4 months (range, 12-64.2 months). All patients demonstrated significant improvement in mHHS, NAHS, HOS-SSS, and VAS (P \u3c.001) at latest follow-up. Additionally, 84.4% achieved MCID and 81.3% achieved PASS for mHHS, and 87.5% achieved MCID and 75% achieved PASS for HOS-SSS. VAS pain scores decreased from 4.4 to 1.8, and the satisfaction with surgery was 7.9 out of 10. The rate of return to sport was 78%.
Conclusion: At minimum 1-year follow-up, primary arthroscopic labral reconstruction, in the setting of femoroacetabular impingement syndrome and irreparable labral tears, was associated with significant improvement in PROs in athletic populations. Return to sport within 1 year of surgery was 78%
Carcinoids and Capsules: A Case Series Highlighting the Utility of Capsule Endoscopy in Patients With Small Bowel Carcinoids
Background: Neuroendocine tumors (NETs) or carcinoids arise at many different sites of the gastrointestinal tract. The small intestine is the most common site for NETs. Diagnosing small bowel carcinoids remains challenging given their non-specific presentations and the overall low incidence of small bowel tumors. Video capsule endoscopy (VCE) has significanly improved our ability to detect small bowel malignancies. We explore the value of VCE in the initial workup and management of a series of small bowel carcinoid patients.
Methods: We retrospectively analyzed adult patients undergoing surgical management for small bowel lesions from July 2005 to September 2015 at a tertiary care center. Patient characteristics, presenting symptomatology, diagnostic workup and surgical management were analyzed among patients with histologically confirmed small bowel carcinoid tumors.
Results: Our study identified 16 patients treated surgically for small bowel carcinoids. The majority of patients (87.5%) presented with either occult gastrointestinal bleeding or anemia. Most patients (87.5%) were initially evaluated with various endoscopic and imaging modalities before all ultimately undergoing surgery. Seventy-five percent of patients had a VCE, with 83.3% (10/12) having positive findings that correlated with intraoperative findings compared to 62.5% (5/8) with computed tomography scan, 21.4% (3/14) with colonoscopy, 44% (4/9) with deep enteroscopy, and 0% (0/9) with esophagogastroduodenoscopy (EGD).
Conclusions: In the absence of any contraindications, VCE is an effective endoscopic modality in the diagnostic workup of small bowel NETs. Furthermore, positive VCE findings appear to highly correlate with surgical findings, thus suggesting a valuable role for VCE in the initial surgical assessment of patients with small bowel NETs
Microvascular resistance predicts myocardial salvage and infarct characteristics in ST-elevation myocardial infarction
<b>Background:</b> The pathophysiology of myocardial injury and repair in patients with ST‐elevation myocardial infarction is incompletely understood. We investigated the relationships among culprit artery microvascular resistance, myocardial salvage, and ventricular function.<p></p>
<b>Methods and Results:</b> The index of microvascular resistance (IMR) was measured by means of a pressure‐ and temperature‐sensitive coronary guidewire in 108 patients with ST‐elevation myocardial infarction (83% male) at the end of primary percutaneous coronary intervention. Paired cardiac MRI (cardiac magnetic resonance) scans were performed early (2 days; n=108) and late (3 months; n=96) after myocardial infarction. T2‐weighted‐ and late gadolinium–enhanced cardiac magnetic resonance delineated the ischemic area at risk and infarct size, respectively. Myocardial salvage was calculated by subtracting infarct size from area at risk. Univariable and multivariable models were constructed to determine the impact of IMR on cardiac magnetic resonance–derived surrogate outcomes. The median (interquartile range) IMR was 28 (17–42) mm Hg/s. The median (interquartile range) area at risk was 32% (24%–41%) of left ventricular mass, and the myocardial salvage index was 21% (11%–43%). IMR was a significant multivariable predictor of early myocardial salvage, with a multiplicative effect of 0.87 (95% confidence interval 0.82 to 0.92) per 20% increase in IMR; P<0.001. In patients with anterior myocardial infarction, IMR was a multivariable predictor of early and late myocardial salvage, with multiplicative effects of 0.82 (95% confidence interval 0.75 to 0.90; P<0.001) and 0.92 (95% confidence interval 0.88 to 0.96; P<0.001), respectively. IMR also predicted the presence and extent of microvascular obstruction and myocardial hemorrhage.<p></p>
<b>Conclusion:</b> Microvascular resistance measured during primary percutaneous coronary intervention significantly predicts myocardial salvage, infarct characteristics, and left ventricular ejection fraction in patients with ST‐elevation myocardial infarction.<p></p>
Medical Device Innovation: Prospective Solutions for an Ecosystem in Crisis Adding a Professional Society Perspective
Barriers to medical device innovation compromise timelines and costs from bench to bedside. Fragmented strategies by individual competitors are no longer sustainable. Pragmatically focused pre-competitive collaboration across stakeholders approaches innovation as an ecosystem. Desiloing experience and expertise encourages high-impact infrastructure efficiencies unique to pre-competitive constructs. Alignment of processes and objectives across the regulatory, reimbursement, clinical research, and clinical practice enterprises, with particular attention to the total product life cycle and continuous accrual of safety information, promotes more predictable equipoise for speed of access relative to residual safety concerns. Professional societies are well positioned to convene pre-competitive dialogue, facilitate alignment, and add perspective to equipoise within the innovation ecosystem
Introducing BAX: a database for X-ray clusters and groups of galaxies
We present BAX, Base de Donnees Amas de Galaxies X
(http://webast.ast.obs-mip.fr/bax), a multi-wavelength database dedicated to
X-ray clusters and groups of galaxies allowing detailed information retrieval.
BAX is designed to support astronomical research by providing access to
published measurements of the main physical quantities and to the related
bibliographic references: basic data stored in the database are cluster/group
identifiers, equatorial coordinates, redshift, flux, X-ray luminosity (in the
ROSAT band) and temperature, and links to additional linked parameters (in
X-rays, such as spatial profile parameters, as well as SZ parameters of the hot
gas, lensing measurements,and data at other wavelengths, such as optical and
radio). The clusters and groups in BAX can be queried by the basic parameters
as well as the linked parameters or combinations of these. We expect BAX to
become an important tool for the astronomical community. BAX will optimize
various aspects of the scientific analysis of X-ray clusters and groups of
galaxies, from proposal planning to data collection, interpretation and
publication, from both ground based facilities like MEGACAM (CFHT), VIRMOS
(VLT) and space missions like XMM-Newton, Chandra and Planck.Comment: Accepted for publication in Astronomy and Astrophysics Journal.
Contains 4 pages and 1 figur
Academic Librarianship and the Redefining Scholarship Project: A Report from the Association of College and Research Libraries Task Force on Institutional Priorities and Faculty Rewards
At the July, 1996 Annual Conference of the American Library Association, the Board of Directors of the Association of College and Research Libraries (ACRL) appointed a task force to write a formal statement defining and describing the kind of scholarship performed by academic librarians, using as a framework the taxonomy developed by Eugene Rice and elaborated by Ernest Boyer in his 1990 book Scholarship Reconsidered: Priorities of the Professoriate.(1) The task force\u27s statement, upon approval by the ACRL Board, is intended to become part of a larger movement established by Syracuse University\u27s Center for Instructional Development, entitled the Institutional Priorities and Faculty Rewards project. The project, which is being funded by the Lilly Endowment, with support from the Fund for the Improvement of Postsecondary Education, is providing assistance to academic associations for the development and dissemination of definitions of scholarship for their disciplines. The definitions are intended to extend the range of activities recognized as scholarly for the purposes of tenure, promotion, merit, or reward system guidelines. The following is the report of the ACRL task force
Phase evolution in calcium molybdate nanoparticles as a function of synthesis temperature and its electrochemical effect on energy storage
The design of a suitable electrode is an essential and fundamental research challenge in the field of electrochemical energy storage because the electronic structures and morphologies determine the surface redox reactions. Calcium molybdate (CaMoO) was synthesized by a combustion route at 300 °C and 500 °C. We describe new findings on the behaviour of CaMoO and evaluate the influence of crystallinity on energy storage performance. A wide range of characterization techniques was used to obtain detailed information about the physical and morphological characteristics of CaMoO. The characterization results enable the phase evolution as a function of the electrode synthesis temperature to be understood. The crystallinity of the materials was found to increase with increasing temperature but with no second phases observed. Molecular dynamics simulation of electronic structures correlated well with the experimental findings. These results show that to enable faster energy storage and release for a given surface area, amorphous CaMoO is required, while larger energy storage can be obtained by using crystalline CaMoO. CaMoO has been evaluated as a cathode material in classical lithium-ion batteries recently. However, determining the surface properties in a sodium-ion system experimentally, combined with computational modelling to understand the results has not been reported. The superior electrochemical properties of crystalline CaMoO are attributed to its morphology providing enhanced Na ion diffusivity and electron transport. However, the presence of carbon in amorphous CaMoO resulted in excellent rate capability, suitable for supercapacitor applications
Overcoming the barriers to implementing urban road user charging schemes
Urban road user charging offers the potential to achieve significant improvements in urban transport, but is notoriously difficult to implement. Cities need guidance on the range of factors to be considered in planning and implementing such schemes. This paper summarises the results of a 3 year programme which has collated evidence on the issues of most concern to cities. A state of the art report has provided evidence on 14 themes, ranging from objectives and design to implementation and evaluation. A set of 16 case studies has reviewed experience in design and implementation across Europe. The paper summarises their findings, provides references to more detailed information, presents the resulting policy recommendations to European, national and local government, and outlines the areas in which further research is needed
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