6,230 research outputs found

    Quantifying innovation in surgery

    Get PDF
    Objectives: The objectives of this study were to assess the applicability of patents and publications as metrics of surgical technology and innovation; evaluate the historical relationship between patents and publications; develop a methodology that can be used to determine the rate of innovation growth in any given health care technology. Background: The study of health care innovation represents an emerging academic field, yet it is limited by a lack of valid scientific methods for quantitative analysis. This article explores and cross-validates 2 innovation metrics using surgical technology as an exemplar. Methods: Electronic patenting databases and the MEDLINE database were searched between 1980 and 2010 for “surgeon” OR “surgical” OR “surgery.” Resulting patent codes were grouped into technology clusters. Growth curves were plotted for these technology clusters to establish the rate and characteristics of growth. Results: The initial search retrieved 52,046 patents and 1,801,075 publications. The top performing technology cluster of the last 30 years was minimally invasive surgery. Robotic surgery, surgical staplers, and image guidance were the most emergent technology clusters. When examining the growth curves for these clusters they were found to follow an S-shaped pattern of growth, with the emergent technologies lying on the exponential phases of their respective growth curves. In addition, publication and patent counts were closely correlated in areas of technology expansion. Conclusions: This article demonstrates the utility of publically available patent and publication data to quantify innovations within surgical technology and proposes a novel methodology for assessing and forecasting areas of technological innovation

    Cognitive Control of Escape Behaviour

    Get PDF
    When faced with potential predators, animals instinctively decide whether there is a threat they should escape from, and also when, how, and where to take evasive action. While escape is often viewed in classical ethology as an action that is released upon presentation of specific stimuli, successful and adaptive escape behaviour relies on integrating information from sensory systems, stored knowledge, and internal states. From a neuroscience perspective, escape is an incredibly rich model that provides opportunities for investigating processes such as perceptual and value-based decision-making, or action selection, in an ethological setting. We review recent research from laboratory and field studies that explore, at the behavioural and mechanistic levels, how elements from multiple information streams are integrated to generate flexible escape behaviour

    Calibration of a single atom detector for atomic micro chips

    Get PDF
    We experimentally investigate a scheme for detecting single atoms magnetically trapped on an atom chip. The detector is based on the photoionization of atoms and the subsequent detection of the generated ions. We describe the characterization of the ion detector with emphasis on its calibration via the correlation of ions with simultaneously generated electrons. A detection efficiency of 47.8% (+-2.6%) is measured, which is useful for single atom detection, and close to the limit allowing atom counting with sub-Poissonian uncertainty

    Modelling the [Fe II]  λ1.644 μm outflow and comparison with H₂ and H+ kinematics in the inner 200 pc of NGC 1068

    No full text
    We map the kinematics of the inner (200 pc) narrow-line region (NLR) of the Seyfert 2 galaxy NGC 1068 using the instrument Near-infrared Integral Field Spectrograph and adaptive optics at the Gemini North telescope. Channel maps and position–velocity diagrams are presented at a spatial resolution of ≅8 pc and spectral resolution ∼5300 in the emission lines [Fe II] λ1.644 μm, H₂ λ2.122 μm and Brγ. The [Fe II] emission line provides a better coverage of the NLR outflow than the previously used [O III] λ5007 emission line, extending beyond the area of the bipolar cone observed in Brγ and [O III]. This is mainly due to the contribution of the redshifted channels to the north-east of the nucleus, supporting its origin in a partial ionized zone with additional contribution from shocks of the outflowing gas with the galactic disc. We modelled the kinematics and geometry of the [Fe II] emitting gas finding good agreement with the data for outflow models with conical and lemniscate (or hourglass) geometry. We calculate a mass outflow rate of 1.9⁺²ˍ₁ M⊙ yr⁻¹ but a power for the outflow of only 0.08 per cent LBol. The molecular (H₂) gas kinematics is completely distinct from that of [Fe II] and Brγ, showing radial expansion in an off-centred ∼100 pc radius ring in the galaxy plane. The expansion velocity decelerates from ≈200 km s−1 in the inner border of the ring to approximately zero at the outer border where our previous studies found a 10 Myr stellar population

    Cost-effectiveness of methenamine hippurate compared with antibiotic prophylaxis for the management of recurrent urinary tract infections in secondary care: a multicentre, open-label, randomised, non-inferiority trial

    Get PDF
    \ua9 Author(s) (or their employer(s)) 2024.Objectives To estimate the cost-effectiveness of methenamine hippurate compared with antibiotic prophylaxis in the management of recurrent urinary tract infections. Design Multicentre, open-label, randomised, non-inferiority trial. Setting Eight centres in the UK, recruiting from June 2016 to June 2018. Participants Women aged ≥18 years with recurrent urinary tract infections, requiring prophylactic treatment. Interventions Women were randomised to receive once-daily antibiotic prophylaxis or twice-daily methenamine hippurate for 12 months. Treatment allocation was not masked and crossover between arms was allowed. Primary and secondary outcome measures The primary economic outcome was the incremental cost per quality-adjusted life year (QALY) gained at 18 months. All costs were collected from a UK National Health Service perspective. QALYs were estimated based on responses to the EQ-5D-5L administered at baseline, 3, 6, 9, 12 and 18 months. Incremental costs and QALYs were estimated using an adjusted analysis which controlled for observed and unobserved characteristics. Stochastic sensitivity analysis was used to illustrate uncertainty on a cost-effectiveness plane and a cost-effectiveness acceptability curve. A sensitivity analysis, not specified in the protocol, considered the costs associated with antibiotic resistance. Results Data on 205 participants were included in the economic analysis. On average, methenamine hippurate was less costly (−\ua340; 95% CI: −684 to 603) and more effective (0.014 QALYs; 95% CI: −0.05 to 0.07) than antibiotic prophylaxis. Over the range of values considered for an additional QALY, the probability of methenamine hippurate being considered cost-effective ranged from 51% to 67%. Conclusions On average, methenamine hippurate was less costly and more effective than antibiotic prophylaxis but these results are subject to uncertainty. Methenamine hippurate is more likely to be considered cost-effectiv

    A role for the Ral guanine nucleotide dissociation stimulator in mediating Ras-induced transformation

    Get PDF
    Oncogenic Ras transforms cells through the activation of multiple downstream pathways mediated by separate effector molecules, one of which is Raf. Here we report the identification of a second ras-binding protein that can induce cellular transformation in parallel with activation of the Raf/mitogen-activated protein kinase cascade. The Ral guanine nucleotide dissociation stimulator (RalGDS) was isolated from a screen for Ras-binding proteins that specifically interact with a Ras effector-loop mutant, ras(12V,37G), that uncouples Ras from activation of Raf1. RalGDS, like ras(12V, 37G), cooperates synergistically with mutationally activated Raf to induce foci of growth and morphologically transformed NIH 3T3 cells. RalGDS does not significantly enhance MAP kinase activation by activated Raf, suggesting that the cooperativity in focus formation is due to a distinct pathway acting downstream of Ras and parallel to Raf

    Energetics of Forced Thermal Ratchet

    Get PDF
    Molecular motors are known to have the high efficiency of energy transformation in the presence of thermal fluctuation. Motivated by the surprising fact, recent studies of thermal ratchet models are showing how and when work should be extracted from non-equilibrium fluctuations. One of the important finding was brought by Magnasco where he studied the temperature dependence on the fluctuation-induced current in a ratchet (multistable) system and showed that the current can generically be maximized in a finite temperature. The interesting finding has been interpreted that thermal fluctuation is not harmful for the fluctuation-induced work and even facilitates its efficiency. We show, however, this interpretation turns out to be incorrect as soon as we go into the realm of the energetics [Sekimoto,J.Phys.Soc.Jpn.66,1234-1237(1997)]: the efficiency of energy transformation is not maximized at finite temperature, even in the same system that Magnasco considered. The maximum efficiency is realized in the absence of thermal fluctuation. The result presents an open problem whether thermal fluctuation could facilitate the efficiency of energetic transformation from force-fluctuation into work.Comment: 3pages, 4sets of figure

    Dissipation Enhanced Asymmetric Transport in Quantum Ratchets

    Full text link
    Quantum mechanical motion of a particle in a periodic asymmetric potential is studied theoretically at zero temperature. It is shown based on semi-classical approximation that the tunneling probability from one local minimum to the next becomes asymmetric in the presence of weak oscillating field, even though there is no macroscopic field gradient in average. Dissipation enhances this asymmetry, and leads to a steady unidirectional current, resulting in a quantum ratchet system.Comment: 12 pages, 2 Figures, submitted to J. Phys. Soc. Jp

    Late widespread skeletal metastases from myxoid liposarcoma detected by MRI only

    Get PDF
    Background Myxoid liposarcoma is the second most commonly occurring sub-type of liposarcomas. In contrast to other soft tissue sarcomas, it is known to have a tendency to spread toward extrapulmonary sites, such as soft tissues, retroperitoneum, and the peritoneal surface. Bony spread, however, is not as common. Case presentation We report an unusual case of diffuse skeletal metastases from myxoid liposarcoma occurring 13 years after treatment of the primary tumour in the left lower limb. The skeletal spread of the disease was demonstrated on MRI only after other imaging modalities (plain radiography, CT and TC99 bone scans) had failed to detect these metastases. Conclusion MRI is an extremely sensitive and specific screening tool in the detection of skeletal involvement in these types of sarcomas, and therefore, should be a part of the staging proces
    corecore