641 research outputs found

    Wearable Conductive Fiber Sensors for Multi-Axis Human Joint Angle Measurements

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    BACKGROUND: The practice of continuous, long-term monitoring of human joint motion is one that finds many applications, especially in the medical and rehabilitation fields. There is a lack of acceptable devices available to perform such measurements in the field in a reliable and non-intrusive way over a long period of time. The purpose of this study was therefore to develop such a wearable joint monitoring sensor capable of continuous, day-to-day monitoring. METHODS: A novel technique of incorporating conductive fibers into flexible, skin-tight fabrics surrounding a joint is developed. Resistance changes across these conductive fibers are measured, and directly related to specific single or multi-axis joint angles through the use of a non-linear predictor after an initial, one-time calibration. Because these sensors are intended for multiple uses, an automated registration algorithm has been devised using a sensitivity template matched to an array of sensors spanning the joints of interest. In this way, a sensor array can be taken off and put back on an individual for multiple uses, with the sensors automatically calibrating themselves each time. RESULTS: The wearable sensors designed are comfortable, and acceptable for long-term wear in everyday settings. Results have shown the feasibility of this type of sensor, with accurate measurements of joint motion for both a single-axis knee joint and a double axis hip joint when compared to a standard goniometer used to measure joint angles. Self-registration of the sensors was found to be possible with only a few simple motions by the patient. CONCLUSION: After preliminary experiments involving a pants sensing garment for lower body monitoring, it has been seen that this methodology is effective for monitoring joint motion of the hip and knee. This design therefore produces a robust, comfortable, truly wearable joint monitoring device

    Design and analysis of wearable conductive fiber sensors for continuous multi-axis joint angle measurements

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    Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.Includes bibliographical references (leaves 54-56).The practice of continuous, long-term monitoring of human joint motion is one that finds many applications, especially in the medical and rehabilitation fields. There is currently a lack of acceptable devices available to perform such measurements in an accurate and non-intrusive way for a patient over a long period of time, and so a new wearable sensor has been developed. A novel technique of incorporating conductive fibers into flexible, skin-tight fabrics surrounding a joint is used. Resistance changes across these conductive fibers are measured, and directly related to specific single or multi-axis joint angles through the use of a nonlinear predictor after an initial, one-time calibration. These wearable sensors are comfortable, and acceptable for long-term wear in everyday settings. Because these sensors are intended for multiple uses, an automated registration algorithm has been devised using a sensitivity template matched to an array of sensors spanning the joints of interest. In this way, a sensor array can be taken off and put back on an individual for multiple uses, with the sensors automatically calibrating themselves each time. Results have shown the feasibility of this type of sensor, with accurate measurements of joint motion for both a single-axis knee joint and a double axis hip joint when compared to a standard goniometer used to measure joint angles.by Peter T. Gibbs.S.M

    Time-lapse ultrashort pulse microscopy of infection in three-dimensional versus two-dimensional culture environments reveals enhanced extra-chromosomal virus replication compartment formation

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    The mechanisms that enable viruses to harness cellular machinery for their own survival are primarily studied in cell lines cultured in two-dimensional (2-D) environments. However, there are increasing reports of biological differences between cells cultured in 2-D versus three-dimensional (3-D) environments. Here we report differences in host-virus interactions based on differences in culture environment. Using ultrashort pulse microscopy (UPM), a form of two-photon microscopy that utilizes sub-10-fs pulses to efficiently excite fluorophores, we have shown that de novo development of extra-chromosomal virus replication compartments (VRCs) upon murine cytomegalovirus (mCMV) infection is markedly enhanced when host cells are cultured in 3-D collagen gels versus 2-D monolayers. In addition, time-lapse imaging revealed that mCMV-induced VRCs have the capacity to grow by coalescence. This work supports the future potential of 3-D culture as a useful bridge between traditional monolayer cultures and animal models to study host-virus interactions in a more physiologically relevant environment for the development of effective anti-viral therapeutics. These advances will require broader adoption of modalities, such as UPM, to image deep within scattering tissues

    Limitations of student-driven formative assessment in a clinical clerkship. A randomised controlled trial

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    Background Teachers strive to motivate their students to be self-directed learners. One of the methods used is to provide online formative assessment material. The concept of formative assessment and use of these processes is heavily promoted, despite limited evidence as to their efficacy.Methods Fourth year medical students, in their first year of clinical work were divided into four groups. In addition to the usual clinical material, three of the groups were provided with some form of supplementary learning material. For two groups, this was provided as online formative assessment. The amount of time students spent on the supplementary material was measured, their opinion on learning methods was surveyed, and their performance in summative exams at the end of their surgical attachments was measured.Results The performance of students was independent of any educational intervention imposed by this study. Despite its ready availability and promotion, student use of the online formative tools was poor.Conclusion Formative learning is an ideal not necessarily embraced by students. If formative assessment is to work students need to be encouraged to participate, probably by implementing some form of summative assessment.Edward J Palmer and Peter G Devit

    Ampullary cancers harbor ELF3 tumor suppressor gene mutations and exhibit frequent WNT dysregulation

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    The ampulla of Vater is a complex cellular environment from which adenocarcinomas arise to form a group of histopathologically heterogenous tumors. To evaluate the molecular features of these tumors, 98 ampullary adenocarcinomas were evaluated and compared to 44 distal bile duct and 18 duodenal adenocarcinomas. Genomic analyses revealed mutations in the WNT signaling pathway among half of the patients and in all three adenocarcinomas irrespective of their origin and histological morphology. These tumors were characterized by a high frequency of inactivating mutations of ELF3, a high rate of microsatellite instability, and common focal deletions and amplifications, suggesting common attributes in the molecular pathogenesis are at play in these tumors. The high frequency of WNT pathway activating mutation, coupled with small-molecule inhibitors of β-catenin in clinical trials, suggests future treatment decisions for these patients may be guided by genomic analysis

    Vortex imaging in unconventional superconductors

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    The real space imaging of vortices in unconventional superconductors not only provides important information about the effectiveness of flux pinning that can inform high current applications, but also yields crucial insights into the form of the superconducting order parameter. For example, the structure of the vortex lattice reflects effective mass and order parameter anisotropies within the material, and profiles of isolated vortices provide a local measure of the magnetic penetration depth that can be used to infer the superfluid density. We describe here the analysis of recent studies whereby state-of-the-art scanning Hall probe microscopy (SHPM) has been used to perform vortex-resolved magnetic imaging on two distinct families of unconventional superconductors. Two sets of results will be analysed in detail; (i) vortex lattice structural transitions in the p-wave superconductor Sr2RuO4 that reflect underlying anisotropies in the system and (ii) a quantitative analysis of vortex profiles in Co-doped 122 pnictide superconductors (SrFe2-xCoxAs2 &amp; BaFe2-xCoxAs2) that allows one to infer the temperature-dependent superfluid density. The latter has then been compared with predictions for different order parameter models for a multiband superconductor.</p

    Monte Carlo Methods for Estimating Interfacial Free Energies and Line Tensions

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    Excess contributions to the free energy due to interfaces occur for many problems encountered in the statistical physics of condensed matter when coexistence between different phases is possible (e.g. wetting phenomena, nucleation, crystal growth, etc.). This article reviews two methods to estimate both interfacial free energies and line tensions by Monte Carlo simulations of simple models, (e.g. the Ising model, a symmetrical binary Lennard-Jones fluid exhibiting a miscibility gap, and a simple Lennard-Jones fluid). One method is based on thermodynamic integration. This method is useful to study flat and inclined interfaces for Ising lattices, allowing also the estimation of line tensions of three-phase contact lines, when the interfaces meet walls (where "surface fields" may act). A generalization to off-lattice systems is described as well. The second method is based on the sampling of the order parameter distribution of the system throughout the two-phase coexistence region of the model. Both the interface free energies of flat interfaces and of (spherical or cylindrical) droplets (or bubbles) can be estimated, including also systems with walls, where sphere-cap shaped wall-attached droplets occur. The curvature-dependence of the interfacial free energy is discussed, and estimates for the line tensions are compared to results from the thermodynamic integration method. Basic limitations of all these methods are critically discussed, and an outlook on other approaches is given

    Signaling in Secret: Pay-for-Performance and the Incentive and Sorting Effects of Pay Secrecy

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    Key Findings: Pay secrecy adversely impacts individual task performance because it weakens the perception that an increase in performance will be accompanied by increase in pay; Pay secrecy is associated with a decrease in employee performance and retention in pay-for-performance systems, which measure performance using relative (i.e., peer-ranked) criteria rather than an absolute scale (see Figure 2 on page 5); High performing employees tend to be most sensitive to negative pay-for- performance perceptions; There are many signals embedded within HR policies and practices, which can influence employees’ perception of workplace uncertainty/inequity and impact their performance and turnover intentions; and When pay transparency is impractical, organizations may benefit from introducing partial pay openness to mitigate these effects on employee performance and retention

    Pembrolizumab in Asian patients with microsatellite-instability-high/mismatch-repair-deficient colorectal cancer

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    The phase 3 KEYNOTE-177 study evaluated pembrolizumab versus chemotherapy with or without bevacizumab or cetuximab in patients with newly diagnosed, microsatellite-instability-high (MSI-H)/mismatch-repair-deficient (dMMR) metastatic colorectal cancer (mCRC). Primary endpoints were progression-free survival (PFS) per RECIST v1.1 by blinded independent central review (BICR) and overall survival (OS). Secondary endpoints were overall response rate (ORR) per RECIST v1.1 by BICR and safety. Here, we report results from the post hoc analysis of patients who were enrolled in Asia from the final analysis (FA) of KEYNOTE-177. A total of 48 patients from Japan, Korea, Singapore, and Taiwan (pembrolizumab, n =?22; chemotherapy, n =?26) were included. At FA, median time from randomization to data cutoff (February 19, 2021) was 45.3 (range 38.1?57.8) months with pembrolizumab and 43.9 (range 36.6?55.1) months with chemotherapy. Median PFS was not reached (NR; 95% confidence interval [CI] 1.9 months?NR) with pembrolizumab versus 10.4 (95% CI 6.3?22.0) months with chemotherapy (hazard ratio [HR] 0.56, 95% CI 0.26?1.20). Median OS was NR (range 13.8 months?NR) versus 30.0 (14.7?NR) months (HR 0.65, 95% CI 0.27?1.55) and ORR was 50% (95% CI 28?72) versus 46% (95% CI 27?67). Grade 3/4 treatment-related adverse events (TRAEs) were reported by two patients (9%) in the pembrolizumab arm and 20 (80%) in the chemotherapy arm. Immune-mediated adverse events or infusion reactions were reported by six patients (27%) and 10 patients (40%), respectively. No deaths due to TRAEs occurred. These data support first-line pembrolizumab as a standard of care for patients from Asia with MSI-H/dMMR mCRC. ClinicalTrials.gov identifier: NCT02563002.FUNDING INFORMATION: The study was designed under the responsibility of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA, in conjunction with the steering committee. The study was funded by Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA. Pembrolizumab was provided by Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA. All authors had full access to all of the data in the study and had final responsibility for the decision to submit for publication. ACKNOWLEDGMENTS: This work was funded by Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA. We thank the patients and their families and caregivers for participating in this trial, and all investigators and site personnel. Medical writing and editorial assistance were provided by Jemimah Walker, PhD, Mehak Aggarwal, PharmD, and Doyel Mitra, PhD, CMPP, of ApotheCom (Yardley, PA, USA). This assistance was funded by Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA
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