6,486 research outputs found
Driving Factors of Recommending a Hand Surgery Clinic After Surgery
Purpose: Since a patient's recommendation of a clinic to others is an important indicator of patient experience, more insight is needed into the underlying factors that motivate such recommendations. This retrospective cohort study assessed the relative contribution of the following: (1) patient-related characteristics, (2) treatment outcome, (3) satisfaction with treatment outcome, and (4) patientsâ experience with the process of care to patientsâ recommendation of a specific clinic after elective surgery. Methods: Patients of specialized outpatient hand surgery clinics (N = 6,895) reported the likelihood of recommending the clinic to friends or family 3â5 months after surgery by filling in the Net Promoter Score. Potential predictors of the Net Promoter Score were preoperative patient characteristics, patient-reported treatment outcomes, satisfaction with treatment outcome, and experience with several health care delivery domains. Linear regression analyses were used to examine the contribution of the predictors. Results: Mean age of the patients was 53 (SD, 14) years, 62.5% were women, and 62.5% were employed. Preoperative patient characteristics explained 1% of the variance in clinic recommendations. An additional 6% was explained by the treatment outcome, 21.6% by satisfaction with treatment outcome, and 33.8% by patientsâ experience with care delivery (total explained variance was 62.3%). The strongest independent predictors of clinic recommendations were positive experiences with the quality of the facilities and the communication skills of the physician. Conclusions: Patient recommendations are more strongly driven by patientsâ experience with care delivery than by treatment outcome and patient characteristics. Clinical relevance: In elective surgery, improving patient experiences is pivotal in boosting patient recommendation of the clinic.</p
Fast Monte Carlo Simulation for Patient-specific CT/CBCT Imaging Dose Calculation
Recently, X-ray imaging dose from computed tomography (CT) or cone beam CT
(CBCT) scans has become a serious concern. Patient-specific imaging dose
calculation has been proposed for the purpose of dose management. While Monte
Carlo (MC) dose calculation can be quite accurate for this purpose, it suffers
from low computational efficiency. In response to this problem, we have
successfully developed a MC dose calculation package, gCTD, on GPU architecture
under the NVIDIA CUDA platform for fast and accurate estimation of the x-ray
imaging dose received by a patient during a CT or CBCT scan. Techniques have
been developed particularly for the GPU architecture to achieve high
computational efficiency. Dose calculations using CBCT scanning geometry in a
homogeneous water phantom and a heterogeneous Zubal head phantom have shown
good agreement between gCTD and EGSnrc, indicating the accuracy of our code. In
terms of improved efficiency, it is found that gCTD attains a speed-up of ~400
times in the homogeneous water phantom and ~76.6 times in the Zubal phantom
compared to EGSnrc. As for absolute computation time, imaging dose calculation
for the Zubal phantom can be accomplished in ~17 sec with the average relative
standard deviation of 0.4%. Though our gCTD code has been developed and tested
in the context of CBCT scans, with simple modification of geometry it can be
used for assessing imaging dose in CT scans as well.Comment: 18 pages, 7 figures, and 1 tabl
Development of an Hexapod BioMicroRobot with Nafion-Pt IPMC microlegs
This paper presents an artificial locomotion
servo-system for an insect like hexapod BioMicroRobot (BMR). This servo-system, programmed with VHDL code, will act as a driver in a RISC architecture microcontroller to reproduce insect tripod walking. An overview of the robot control system, in accordance with the insect displacement principle, is demonstrated with timing parameters. A control
algorithm of the six legs driving the robot in any direction versus Pulse Width Modulation (PWM) is reviewed. BMR microlegs are built with cylindrical Nafion-Pt Ionomeric Polymer-Metal Composite (IPMC) that have 2.5 degrees of freedom. Specific fabrication process for one leg is exposed.
Dynamic behavior and microleg characteristics have been measured in deionized water using a laser vibrometer. BMR current consumption is an important parameter evaluated for each leg. Hardware test bench to acquired measurement is presented. The purpose of this design is to control a BMR for biomedical goals like implantation in human body. Experimental results on the proposed legs are conclusive for this type of bioinspired BMR
A meta-analytic review of stand-alone interventions to improve body image
Objective
Numerous stand-alone interventions to improve body image have been developed. The
present review used meta-analysis to estimate the effectiveness of such interventions, and
to identify the specific change techniques that lead to improvement in body image.
Methods
The inclusion criteria were that (a) the intervention was stand-alone (i.e., solely focused on
improving body image), (b) a control group was used, (c) participants were randomly
assigned to conditions, and (d) at least one pretest and one posttest measure of body
image was taken. Effect sizes were meta-analysed and moderator analyses were conducted.
A taxonomy of 48 change techniques used in interventions targeted at body image
was developed; all interventions were coded using this taxonomy.
Results
The literature search identified 62 tests of interventions (N = 3,846). Interventions produced
a small-to-medium improvement in body image (d+ = 0.38), a small-to-medium reduction in
beauty ideal internalisation (d+ = -0.37), and a large reduction in social comparison tendencies
(d+ = -0.72). However, the effect size for body image was inflated by bias both within
and across studies, and was reliable but of small magnitude once corrections for bias were
applied. Effect sizes for the other outcomes were no longer reliable once corrections for
bias were applied. Several features of the sample, intervention, and methodology moderated
intervention effects. Twelve change techniques were associated with improvements in
body image, and three techniques were contra-indicated.
Conclusions
The findings show that interventions engender only small improvements in body image, and
underline the need for large-scale, high-quality trials in this area. The review identifies effective
techniques that could be deployed in future interventions
IL-22 mediates goblet cell hyperplasia and worm expulsion in intestinal helminth infection.
Type 2 immune responses are essential in protection against intestinal helminth infections. In this study we show that IL-22, a cytokine important in defence against bacterial infections in the intestinal tract, is also a critical mediator of anti-helminth immunity. After infection with Nippostrongylus brasiliensis, a rodent hookworm, IL-22-deficient mice showed impaired worm expulsion despite normal levels of type 2 cytokine production. The impaired worm expulsion correlated with reduced goblet cell hyperplasia and reduced expression of goblet cell markers. We further confirmed our findings in a second nematode model, the murine whipworm Trichuris muris. T.muris infected IL-22-deficient mice had a similar phenotype to that seen in N.brasiliensis infection, with impaired worm expulsion and reduced goblet cell hyperplasia. Ex vivo and in vitro analysis demonstrated that IL-22 is able to directly induce the expression of several goblet cell markers, including mucins. Taken together, our findings reveal that IL-22 plays an important role in goblet cell activation, and thus, a key role in anti-helminth immunity
Mass sum rules for singly and doubly heavy-flavored hadrons
Regularities in the hadron interaction energies are used to obtain formulas
relating the masses of ground-state hadrons, most of which contain heavy
quarks. Inputs are the constituent quark model, the Feynman-Hellmann theorem,
and the structure of the colormagnetic interaction of QCD. Some of the formulas
can also be obtained from heavy quark effective theory or from
diquark-antiquark supersymmetry. It is argued that the sum rules are more
general than the model from which they are obtained. Where data exist, the
formulas agree quite well with experiment, but most of the sum rules proposed
provide predictions of heavy baryon masses that will be useful for future
measurements.Comment: 13 pages, Plain TeX, no figure
Exploring the Ni redox activity in polyanionic compounds as conceivable high potential cathodes for Na rechargeable batteries
Although nickel-based polyanionic compounds are expected to exhibit a high operating voltage for batteries based on the Ni2+/3+ redox couple activity, some rare experimental studies on the electrochemical performance of these materials are reported, resulting from the poor kinetics of the bulk materials in both Li and Na nonaqueous systems. Herein, the electrochemical activity of the Ni2+/3+ redox couple in the mixed-polyanionic framework Na4Ni3(PO4)2(P2O7) is reported for the first time. This novel material exhibits a remarkably high operating voltage when cycled in sodium cells in both carbonate- and ionic liquid-based electrolytes. The application of a carbon coating and the use of an ionic liquid-based electrolyte enable the reversible sodium ion (de-)insertion in the host structure accompanied by the redox activity of Ni2+/3+ at operating voltages as high as 4.8âV vs Na/Na+. These results present the realization of Ni-based mixed polyanionic compounds with improved electrochemical activity and pave the way for the discovery of new Na-based high potential cathode materials
Monte Carlo study of the effects of system geometry and antiscatter grids on cone-beam CT scatter distributions
Purpose: The proliferation of cone-beam CT (CBCT) has created interest in performance optimization,with x-ray scatter identifie among the main limitations to image quality. CBCT often contends with elevated scatter, but the wide variety of imaging geometry in different CBCT configuration suggests that not all configuration are affected to the same extent. Graphics processing unit (GPU) accelerated Monte Carlo (MC) simulations are employed over a range of imaging geometries to elucidate the factors governing scatter characteristics, effica y of antiscatter grids, guide system design, and augment development of scatter correction.
Methods: A MC x-ray simulator implemented on GPU was accelerated by inclusion of variance reduction techniques (interaction splitting, forced scattering, and forced detection) and extended to include x-ray spectra and analytical models of antiscatter grids and flat-pane detectors. The simulator was applied to small animal (SA), musculoskeletal (MSK) extremity, otolaryngology (Head), breast, interventional C-arm, and on-board (kilovoltage) linear accelerator (Linac) imaging, with an axis-todetector distance (ADD) of 5, 12, 22, 32, 60, and 50 cm, respectively. Each configuratio was modeled with and without an antiscatter grid and with (i) an elliptical cylinder varying 70â280 mm in major axis; and (ii) digital murine and anthropomorphic models. The effects of scatter were evaluated in terms of the angular distribution of scatter incident upon the detector, scatter-to-primary ratio (SPR), artifact magnitude, contrast, contrast-to-noise ratio (CNR), and visual assessment.
Results: Variance reduction yielded improvements in MC simulation efficien y ranging from âź17-fold (for SA CBCT) to âź35-fold (for Head and C-arm), with the most significan acceleration due to interaction splitting (âź6 to âź10-fold increase in efficien y). The benefi of a more extended geometry was evident by virtue of a larger air gapâe.g., for a 16 cm diameter object, the SPR reduced from 1.5 for ADD = 12 cm (MSK geometry) to 1.1 for ADD = 22 cm (Head) and to 0.5 for ADD = 60 cm (C-arm). Grid efficien y was higher for configuration with shorter air gap due to a broader angular distribution of scattered photonsâe.g., scatter rejection factor âź0.8 for MSK geometry versus âź0.65 for C-arm. Grids reduced cupping for all configuration but had limited improvement on scatterinduced streaks and resulted in a loss of CNR for the SA, Breast, and C-arm. Relative contribution of forward-directed scatter increased with a grid (e.g., Rayleigh scatter fraction increasing from âź0.15 without a grid to âź0.25 with a grid for the MSK configuration) resulting in scatter distributions with greater spatial variation (the form of which depended on grid orientation).
Conclusions: A fast MC simulator combining GPU acceleration with variance reduction provided a systematic examination of a range of CBCT configuration in relation to scatter, highlighting the magnitude and spatial uniformity of individual scatter components, illustrating tradeoffs in CNR and artifacts and identifying the system geometries for which grids are more beneficia (e.g., MSK) from those in which an extended geometry is the better defense (e.g., C-arm head imaging). Compact geometries with an antiscatter grid challenge assumptions of slowly varying scatter distributions due to increased contribution of Rayleigh scatter.The research was
supported by academic-industry partnership with Carestream
Health Inc. (Rochester, NY) and National Institutes of Health
(NIH) Grant No. 2R01-CA-112163. A. Sisniega is supported
by FPU grant (Spanish Ministry of Education), AMIT project,
RECAVA-RETIC Network, Project Nos. TEC2010-21619-
C04-01, TEC2011-28972-C02-01, and PI11/00616 (Spanish
Ministry of Science and Education), ARTEMIS program (Comunidad
de Madrid), and PreDiCT-TB partnership.Publicad
Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV
A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay
channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7
TeV is presented. The data were collected at the LHC, with the CMS detector,
and correspond to an integrated luminosity of 4.6 inverse femtobarns. No
significant excess is observed above the background expectation, and upper
limits are set on the Higgs boson production cross section. The presence of the
standard model Higgs boson with a mass in the 270-440 GeV range is excluded at
95% confidence level.Comment: Submitted to JHE
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