CT based volume measurement and estimation in cases of pericardial effusion

The measurement of fluid volumes in cases of pericardial effusion is a necessary procedure during autopsy. With the increased use of virtual autopsy methods in forensics, the need for a quick volume measurement method on computed tomography (CT) data arises, especially since methods such as CT angiography can potentially alter the fluid content in the pericardium. We retrospectively selected 15 cases with hemopericardium, which underwent post-mortem imaging and autopsy. Based on CT data, the pericardial blood volume was estimated using segmentation techniques and downsampling of CT datasets. Additionally, a variety of measures (distances, areas and 3D approximations of the effusion) were examined to find a quick and easy way of estimating the effusion volume. Segmentation of CT images as shown in the present study is a feasible method to measure the pericardial fluid amount accurately. Downsampling of a dataset significantly increases the speed of segmentation without losing too much accuracy. Some of the other methods examined might be used to quickly estimate the severity of the effusion volumes.

Evaluation of a web-based application versus conventional instruction in the undergraduate curriculum of fixed prosthodontics

The present study aims to investigate the implications of web-based delivery of identical learning content for time efficiency and students' performance, as compared to conventional textbook resources.

Inference on Survival Data with Covariate Measurement Error - An Imputation-based Approach

We propose a new method for fitting proportional hazards models with error-prone covariates. Regression coefficients are estimated by solving an estimating equation that is the average of the partial likelihood scores based on imputed true covariates. For the purpose of imputation, a linear spline model is assumed on the baseline hazard. We discuss consistency and asymptotic normality of the resulting estimators, and propose a stochastic approximation scheme to obtain the estimates. The algorithm is easy to implement, and reduces to the ordinary Cox partial likelihood approach when the measurement error has a degenerative distribution. Simulations indicate high efficiency and robustness. We consider the special case where error-prone replicates are available on the unobserved true covariates. As expected, increasing the number of replicate for the unobserved covariates increases efficiency and reduces bias. We illustrate the practical utility of the proposed method with an Eastern Cooperative Oncology Group clinical trial where a genetic marker, c-myc expression level, is subject to measurement error.

Prediction of residential radon exposure of the whole Swiss population: comparison of model-based predictions with measurement-based predictions

Radon plays an important role for human exposure to natural sources of ionizing radiation. The aim of this article is to compare two approaches to estimate mean radon exposure in the Swiss population: model-based predictions at individual level and measurement-based predictions based on measurements aggregated at municipality level. A nationwide model was used to predict radon levels in each household and for each individual based on the corresponding tectonic unit, building age, building type, soil texture, degree of urbanization, and floor. Measurement-based predictions were carried out within a health impact assessment on residential radon and lung cancer. Mean measured radon levels were corrected for the average floor distribution and weighted with population size of each municipality. Model-based predictions yielded a mean radon exposure of the Swiss population of 84.1 Bq/m(3) . Measurement-based predictions yielded an average exposure of 78 Bq/m(3) . This study demonstrates that the model- and the measurement-based predictions provided similar results. The advantage of the measurement-based approach is its simplicity, which is sufficient for assessing exposure distribution in a population. The model-based approach allows predicting radon levels at specific sites, which is needed in an epidemiological study, and the results do not depend on how the measurement sites have been selected.

A Physiological Controller for Turbodynamic Ventricular Assist Devices Based on a Measurement of the Left Ventricular Volume

The current article presents a novel physiological control algorithm for ventricular assist devices (VADs), which is inspired by the preload recruitable stroke work. This controller adapts the hydraulic power output of the VAD to the end-diastolic volume of the left ventricle. We tested this controller on a hybrid mock circulation where the left ventricular volume (LVV) is known, i.e., the problem of measuring the LVV is not addressed in the current article. Experiments were conducted to compare the response of the controller with the physiological and with the pathological circulation, with and without VAD support. A sensitivity analysis was performed to analyze the influence of the controller parameters and the influence of the quality of the LVV signal on the performance of the control algorithm. The results show that the controller induces a response similar to the physiological circulation and effectively prevents over- and underpumping, i.e., ventricular suction and backflow from the aorta to the left ventricle, respectively. The same results are obtained in the case of a disturbed LVV signal. The results presented in the current article motivate the development of a robust, long-term stable sensor to measure the LVV.

Formative Evaluation of the "Time Twisters": A Comic Book Based Obesity Prevention Curriculum for Elementary School Students

Introduction: Obesity is a public health problem, particularly in Hispanic children. Alternative media channels may offer the potential to motivate children to engage in health promoting behaviors. A comic book, “Time Twisters”, was developed to impact screen time use, physical activity, and dietary behavior for elementary school children and evaluated for acceptability and feasibility prior to implementation in a multi-component physical activity intervention. [See PDF for complete abstract]

Self-Assessment in a Competency-Based Curriculum: Preliminary Findings

Introduction: The introduction of the ACGME core competency framework brought challenges of developing appropriate evaluation tools (i.e. self assessment) to provide evidence of competency. Baylor College of Medicine has 43 competency goals organized within the 6 ACGME domains, each domain having 4-10 goals. [See PDF for complete abstract]

GROMOS-C, a novel ground-based microwave radiometer for ozone measurement campaigns

Stratospheric ozone is of major interest as it absorbs most harmful UV radiation from the sun, allowing life on Earth. Ground-based microwave remote sensing is the only method that allows for the measurement of ozone profiles up to the mesopause, over 24 hours and under different weather conditions with high time resolution. In this paper a novel ground-based microwave radiometer is presented. It is called GROMOS-C (GRound based Ozone MOnitoring System for Campaigns), and it has been designed to measure the vertical profile of ozone distribution in the middle atmosphere by observing ozone emission spectra at a frequency of 110.836 GHz. The instrument is designed in a compact way which makes it transportable and suitable for outdoor use in campaigns, an advantageous feature that is lacking in present day ozone radiometers. It is operated through remote control. GROMOS-C is a total power radiometer which uses a pre-amplified heterodyne receiver, and a digital fast Fourier transform spectrometer for the spectral analysis. Among its main new features, the incorporation of different calibration loads stands out; this includes a noise diode and a new type of blackbody target specifically designed for this instrument, based on Peltier elements. The calibration scheme does not depend on the use of liquid nitrogen; therefore GROMOS-C can be operated at remote places with no maintenance requirements. In addition, the instrument can be switched in frequency to observe the CO line at 115 GHz. A description of the main characteristics of GROMOS-C is included in this paper, as well as the results of a first campaign at the High Altitude Research Station at Jungfraujoch (HFSJ), Switzerland. The validation is performed by comparison of the retrieved profiles against equivalent profiles from MLS (Microwave Limb Sounding) satellite data, ECMWF (European Centre for Medium-Range Weather Forecast) model data, as well as our nearby NDACC (Network for the Detection of Atmospheric Composition Change) ozone radiometer measuring at Bern.

Determining the feasibility and acceptability of a garden-based nutrition curriculum for preschoolers

Obesity rates around the nation have risen to epidemic proportions. Rates of childhood obesity are at very high levels with 24.4% of preschool-aged children in the U.S. currently considered as overweight or obese. The percentage of childhood obesity is much higher in the southern part of the United States as compared to the rest of the nation. Minority populations, especially African American and Hispanic, are affected more than other ethnic groups. Obesity prevention programs are needed targeting young children <6 years of age from minority populations. Currently, there are few obesity prevention programs that have been implemented and evaluated in children <6 years of age. Gardening programs have been successful in improving the health status of elementary school children by increasing fruit and vegetable intake and increasing preferences for healthier food choices. However, there is no evidence of the feasibility and acceptability of a garden-based obesity prevention program among preschoolers. This pretest study, a classroom-based gardening curriculum program with 16 lesson plans and coordinating activities for preschool age children (3-5 years old) enrolled in Head Start, provides the opportunity to address this need. The study included 103 preschoolers from two centers and 9 teachers or teachers' aides. Qualitative data on feasibility and acceptability was collected from process evaluation forms of individual lesson plans and focus groups with teachers. Teacher questionnaires assessed individual teacher characteristics and provided feedback regarding the curriculum. Quantitative measures of teachers' self-efficacy, attitudes, and knowledge pertaining to nutrition were analyzed from pre and post-test surveys. Results revealed this preschool garden-based nutrition curriculum was both feasible and acceptable. The program improved teacher's self-efficacy, knowledge, and attitudes about nutrition, with teacher's confidence in ability to teach a gardening curriculum increasing from a mean score of 2.14 to 3.00 from pre to post test (P value = 0.0046). These results indicate implementing garden-based nutrition lessons within preschools is achievable. Employing garden-based nutrition lessons in the classroom is the first step in teaching children about nutrition and gardening concepts. Constructing gardening beds for more hands-on learning is the next proposed step in the larger parent study of this program.^

Fast measurement of cooling and heating rates in standard cryopreservation protocols based on vitrification

Estudio de la cinética de la crioconservación de tejidos vegetales

Spectral BRDF-based determination of proper measurement geometries to characterize color shift of special effect coatings

A reduced set of measurement geometries allows the spectral reflectance of special effect coatings to be predicted for any other geometry. A physical model based on flake-related parameters has been used to determine nonredundant measurement geometries for the complete description of the spectral bidirectional reflectance distribution function (BRDF). The analysis of experimental spectral BRDF was carried out by means of principal component analysis. From this analysis, a set of nine measurement geometries was proposed to characterize special effect coatings. It was shown that, for two different special effect coatings, these geometries provide a good prediction of their complete color shift.