Absolute reliability and concurrent validity of hand held dynamometry and isokinetic dynamometry in the hip, knee and ankle joint: Systematic review and meta-analysis

Indexación: Scopus.The purpose of the study is to establish absolute reliability and concurrent validity between hand-held dynamometers (HHDs) and isokinetic dynamometers (IDs) in lower extremity peak torque assessment. Medline, Embase, CINAHL databases were searched for studies related to psychometric properties in muscle dynamometry. Studies considering standard error of measurement SEM (%) or limit of agreement LOA (%) expressed as percentage of the mean, were considered to establish absolute reliability while studies using intra-class correlation coefficient (ICC) were considered to establish concurrent validity between dynamometers. In total, 17 studies were included in the meta-analysis. The COSMIN checklist classified them between fair and poor. Using HHDs, knee extension LOA (%) was 33.59%, 95% confidence interval (CI) 23.91 to 43.26 and ankle plantar flexion LOA (%) was 48.87%, CI 35.19 to 62.56. Using IDs, hip adduction and extension; knee flexion and extension; and ankle dorsiflexion showed LOA (%) under 15%. Lower hip, knee, and ankle LOA (%) were obtained using an ID compared to HHD. ICC between devices ranged between 0.62, CI (0.37 to 0.87) for ankle dorsiflexion to 0.94, IC (0.91to 0.98) for hip adduction. Very high correlation were found for hip adductors and hip flexors and moderate correlations for knee flexors/extensors and ankle plantar/dorsiflexors.https://www.degruyter.com/view/j/med.2017.12.issue-1/med-2017-0052/med-2017-0052.xm

An AI-based solution for wireless channel interference prediction and wireless remote control

Abstract. Most control systems rely on wired connectivity between controllers and plants due to their need for fast and reliable real-time control. Yet the demand for mobility, scalability, low operational and maintenance costs call for wireless networked control system designs. Naturally, over-the-air communication is susceptible to interference and fading and therefore, enabling low latency and high reliability is crucial for wireless control scenarios. In this view, the work of this thesis aims to enhance reliability of the wireless communication and to optimize the energy consumption while maintaining low latency and the stability of the controller-plant system. To achieve this goal, two core abstractions have been used, a neural wireless channel interference predictor and a neural predictive controller. This neural predictor design is motivated by the capability of machine learning in assimilating underlying patterns and dynamics of systems using the observed data. The system model is composed of a controller-plant scheme on which the controller transmits control signals wirelessly. The neural wireless predictor and the neural controller predict wireless channel interference and plant states, respectively. This information is used to optimize energy consumption and prevent communication outages while controlling the plant. This thesis presents the development of the neural wireless predictor, the neural controller and a neural plant. Interaction and functionality of these elements are demonstrated using a Simulink simulation. Results of simulation illustrate the effectiveness of neural networks in both control and wireless domain. The proposed solution yields about 17% reduction in energy consumption compared to state-of-the-art designs by minimizing the impact of interference in the control links while ensuring plant stability

Virtual edge illumination and one dimensional beam tracking for absorption, refraction, and scattering retrieval

We propose two different approaches to retrieve x-ray absorption, refraction, and scattering signals using a one dimensional scan and a high resolution detector. The first method can be easily implemented in existing procedures developed for edge illumination to retrieve absorption and refraction signals, giving comparable image quality while reducing exposure time and delivered dose. The second method tracks the variations of the beam intensity profile on the detector through a multi-Gaussian interpolation, allowing the additional retrieval of the scattering signal

Digital Correlation of Ion and Optical Microscopic Images: Application to the Study of Thyroglobulin Chemical Modification

A method has been developed in order to digitally correlate ion and optical microscopic images of the same sample areas. Serial cross-sections of human thyroid tissue were analyzed by secondary ion mass microscopy and by light microscopy. The resulting chemical and immunochemical map images were superimposed and correlated by means of a two-pass registration algorithm which allows to correct for geometrical distortions introduced by the ion microscope. Results are presented for the study of thyroglobulin chemical modification in pathological thyroid tissue that demonstrates heterogeneous molecular activity

Modulation Transfer Function (MTF) evaluation for x-ray phase imaging system employing attenuation masks

OBJECTIVE: Attenuation masks can be used in x-ray imaging systems to increase their inherent spatial resolution and/or make them sensitive to phase effects, a typical example being Edge Illumination X-ray phase contrast imaging (EI-XPCI). This work investigates the performance of a mask-based system such as EI-XPCI in terms of Modulation Transfer Function (MTF), in the absence of phase effects. APPROACH: Pre-sampled MTF measurements, using an edge, were performed on the same system implemented without masks, with non-skipped masks and finally with skipped masks (i.e., masks in which apertures illuminate every other pixel row/column). Results are compared to simulations and finally images of a resolution bar pattern acquired with all the above setups are presented. MAIN RESULTS: Compared to the detector's inherent MTF, the non-skipped mask setup provides improved MTF results. In comparison to an ideal case where signal spill-out into neighbouring pixels is negligible, this improvement takes place only at specific frequencies of the MTF, dictated by the spatial repetition of the spill-out signal. This is limited with skipped masks, which indeed provide further MTF improvements over a larger frequency range. Experimental MTF measurements are supported through simulation and resolution bar pattern images. SIGNIFICANCE: This work has quantified the improvement in MTF due to the use of attenuation masks and lays the foundation for how acceptance and routine quality control tests will have to be modified when systems using masks are introduced in clinical practice and how MTF results will compare to those of conventional imaging systems

Small angle x-ray scattering with edge-illumination

Sensitivity to sub-pixel sample features has been demonstrated as a valuable capability of phase contrast x-ray imaging. Here, we report on a method to obtain angular-resolved small angle x-ray scattering distributions with edge-illumination- based imaging utilizing incoherent illumination from an x-ray tube. Our approach provides both the three established image modalities (absorption, differential phase and scatter strength), plus a number of additional contrasts related to unresolved sample features. The complementarity of these contrasts is experimentally validated by using different materials in powder form. As a significant application example we show that the extended complementary contrasts could allow the diagnosis of pulmonary emphysema in a murine model. In support of this, we demonstrate that the properties of the retrieved scattering distributions are consistent with the expectation of increased feature sizes related to pulmonary emphysema. Combined with the simplicity of implementation of edge-illumination, these findings suggest a high potential for exploiting extended sub-pixel contrasts in the diagnosis of lung diseases and beyond

Three different ways of implementing cycloidal computed tomography: a discussion of pros and cons

We present three implementation strategies for cycloidal computed tomography. The latter refers to an imaging concept that enables the acquisition of highresolution tomograms in a flexible manner (e.g. with x-ray sources with a relatively large focal spot and detectors with relatively large pixels). In cycloidal computed tomography, the sample is rotated and laterally translated simultaneously; with this scheme, each sample feature follows a cycloidal trajectory. This has been shown to reduce scanning time and delivered dose, while maintaining a high resolution. The different ways of implementing this method are: step-and-shoot, continuous unidirectional and continuous back-and-forth translation. While step-andshoot acquisitions yields the best results and are easiest to implement, they are also the most time-consuming. The continuous unidirectional method can be implemented with little effort and gives results comparable to step-and-shoot. Finally, back-and-forth scans can be implemented easily and provide similar results, although there appears to be a small loss in image quality. We present a comprehensive guide on using cycloidal sampling in practice

Assessing the forming temperature role on amorphous and polycrystalline HfO2-based 4 kbit RRAM arrays performance

The impact of temperature during the forming operation on the electrical cells performance and the post-programming stability were evaluated in amorphous and polycrystalline HfO2-based arrays. Forming (between − 40 and 150 °C), reset and set (at room temperature) operations were applied using the incremental step pulse with verify algorithm (ISPVA). The improvements achieved on the forming operation in terms of time and voltages reduction do not impact the subsequent reset/set results. ISPVA perturbations in LRS/HRS current distributions are almost negligible after the first reset/set operation. In this study the best improvement in forming operation in terms of yield, voltage values and cell-to-cell variability is achieved in polycrystalline samples at 80 °C

Rapid and flexible high-resolution scanning enabled by cycloidal computed tomography and convolutional neural network (CNN) based data recovery

We have combined a recently developed imaging concept (“cycloidal computed tomography”) with convolutional neural network (CNN) based data recovery. The imaging concept is enabled by exploiting, in synergy, the benefits of probing the sample with a structured x-ray beam and applying a cycloidal acquisition scheme by which the sample is simultaneously rotated and laterally translated. The beam structuring provides a means of increasing the in-slice spatial resolution in tomographic images irrespective of the blur imposed by the x-ray source and detector, while the “roto-translation” sampling allows for rapid scanning. Data recovery based on the recently proposed Mixed-Scale Dense (MSD) CNN architecture enables an efficient reconstruction of high-quality, high-resolution images despite the fact that cycloidal computed tomography data are highly incomplete. In the following, we review the basic principles underpinning cycloidal computed tomography, introduce the CNN based data recovery method and discuss the benefit of combining both