Prediction of atrial fibrillation from at-home single-lead ECG signals without arrhythmias.

Early identification of atrial fibrillation (AF) can reduce the risk of stroke, heart failure, and other serious cardiovascular outcomes. However, paroxysmal AF may not be detected even after a two-week continuous monitoring period. We developed a model to quantify the risk of near-term AF in a two-week period, based on AF-free ECG intervals of up to 24 h from 459,889 patch-based ambulatory single-lead ECG (modified lead II) recordings of up to 14 days.

Characterization of 475 Novel, Putative Small RNAs (sRNAs) in Carbon-Starved Serovar Typhimurium.

An increasingly apparent role of noncoding RNA (ncRNAs) is to coordinate gene expression during environmental stress. A mounting body of evidence implicates small RNAs (sRNAs) as key drivers of stress survival. Generally thought to be 50-500 nucleotides in length and to occur in intergenic regions, sRNAs typically regulate protein expression through base pairing with mRNA targets.

Magnetic resonance elastography (MRE) shows significant reduction of thigh muscle stiffness in healthy older adults.

Determining the effect of ageing on thigh muscle stiffness using magnetic resonance elastography (MRE) and investigate whether fat fraction and muscle cross-sectional area (CSA) are related to stiffness. Six healthy older adults in their eighth and ninth decade and eight healthy young men were recruited and underwent a 3 T MRI protocol including MRE and Dixon fat fraction imaging. Muscle stiffness, fat fraction and muscle CSA were calculated in ROIs corresponding to the four quadriceps muscles (i.

Characterization of novel small RNAs (sRNAs) contributing to the desiccation response of serovar Typhimurium.

Noncoding RNA (ncRNA) modulation of gene expression has now been ubiquitously observed across all domains of life. An increasingly apparent role of ncRNAs is to coordinate changes in gene expressions in response to environmental stress. , a common food-born pathogen, is known for its striking ability to survive, adapt, and thrive in various unfavourable environments which makes it a particularly difficult pathogen to eliminate as well as an interesting model in which to study ncRNA contributions to cellular stress response.

Fast Robust Dejitter and Interslice Discontinuity Removal in MRI Phase Acquisitions: Application to Magnetic Resonance Elastography.

MRI phase contrast imaging methods that assemble slice-wise acquisitions into volumes can contain interslice phase discontinuities (IPDs) over the course of the scan from sources, including unavoidable physiological activity. In magnetic resonance elastography (MRE), this can alter wavelength and tissue stiffness estimates, invalidating the analysis. We first model this behavior as jitter along the z-axis of the phase of 3D complex-valued wave volumes.

Fast tomoelastography of the mouse brain by multifrequency single-shot MR elastography.

Purpose: To introduce in vivo multifrequency single-shot magnetic resonance elastography for full-FOV stiffness mapping of the mouse brain and to compare in vivo stiffness of neural tissues with different white-to-gray matter ratios.

Methods: Viscous phantoms and 10 C57BL-6 mice were investigated by 7T small-animal MRI using a single-shot spin-echo planar imaging magnetic resonance elastography sequence with motion-encoding gradients positioned before the refocusing pulse. Wave images were acquired over 10 minutes for 6 mechanical vibration frequencies between 900 and 1400 Hz.

ADAR Mediated RNA Editing Modulates MicroRNA Targeting in Human Breast Cancer.

RNA editing by RNA specific adenosine deaminase acting on RNA (ADAR) is increasingly being found to alter microRNA (miRNA) regulation. Editing of miRNA transcripts can affect their processing, as well as which messenger RNAs (mRNAs) they target. Further, editing of target mRNAs can also affect their complementarity to miRNAs.

Heterogeneous Multifrequency Direct Inversion (HMDI) for magnetic resonance elastography with application to a clinical brain exam.

A new viscoelastic wave inversion method for MRE, called Heterogeneous Multifrequency Direct Inversion (HMDI), was developed which accommodates heterogeneous elasticity within a direct inversion (DI) by incorporating first-order gradients and combining results from a narrow band of multiple frequencies. The method is compared with a Helmholtz-type DI, Multifrequency Dual Elasto-Visco inversion (MDEV), both on ground-truth Finite Element Method simulations at varied noise levels and a prospective in vivo brain cohort of 48 subjects ages 18-65. In simulated data, MDEV recovered background material within 5% and HMDI within 1% of prescribed up to SNR of 20 dB.

Human snoRNA-93 is processed into a microRNA-like RNA that promotes breast cancer cell invasion.

Genetic searches for tumor suppressors have recently linked small nucleolar RNA misregulations with tumorigenesis. In addition to their classically defined functions, several small nucleolar RNAs are now known to be processed into short microRNA-like fragments called small nucleolar RNA-derived RNAs. To determine if any small nucleolar RNA-derived RNAs contribute to breast malignancy, we recently performed a RNA-seq-based comparison of the small nucleolar RNA-derived RNAs of two breast cancer cell lines (MCF-7 and MDA-MB-231) and identified small nucleolar RNA-derived RNAs derived from 13 small nucleolar RNAs overexpressed in MDA-MB-231s.

Finite element analysis to investigate variability of MR elastography in the human thigh.

Purpose: To develop finite element analysis (FEA) of magnetic resonance elastography (MRE) in the human thigh and investigate inter-individual variability of measurement of muscle mechanical properties.

Methods: Segmentation was performed on MRI datasets of the human thigh from 5 individuals and FEA models consisting of 12 muscles and surrounding tissue created. The same material properties were applied to each tissue type and a previously developed transient FEA method of simulating MRE using Abaqus was performed at 4 frequencies.

MR elastography measurement of the effect of passive warmup prior to eccentric exercise on thigh muscle mechanical properties.

Purpose: To investigate the effect of warmup by application of the thermal agent Deep Heat (DH) on muscle mechanical properties using magnetic resonance elastography (MRE) at 3T before and after exercise-induced muscle damage (EIMD).

Materials And Methods: Twenty male participants performed an individualized protocol designed to induce EIMD in the quadriceps. DH was applied to the thigh in 50% of the participants before exercise.

Perfusion alters stiffness of deep gray matter.

Viscoelastic properties of the brain reflect tissue architecture at multiple length scales. However, little is known about the relation between vital tissue functions, such as perfusion, and the macroscopic mechanical properties of cerebral tissue. In this study, arterial spin labelling is paired with magnetic resonance elastography to investigate the relationship between tissue stiffness and cerebral blood flow (CBF) in the in vivo human brain.

Magnetic resonance elastography (MRE) of the human brain: technique, findings and clinical applications.

Neurological disorders are one of the most important public health concerns in developed countries. Established brain imaging techniques such as magnetic resonance imaging (MRI) and x-ray computerised tomography (CT) have been essential in the identification and diagnosis of a wide range of disorders, although usually are insufficient in sensitivity for detecting subtle pathological alterations to the brain prior to the onset of clinical symptoms-at a time when prognosis for treatment is more favourable. The mechanical properties of biological tissue provide information related to the strength and integrity of the cellular microstructure.

Increasing the spatial resolution and sensitivity of magnetic resonance elastography by correcting for subject motion and susceptibility-induced image distortions.

Purpose: To improve the resolution of elasticity maps by adapting motion and distortion correction methods for phase-based magnetic resonance imaging (MRI) contrasts such as magnetic resonance elastography (MRE), a technique for measuring mechanical tissue properties in vivo.

Materials And Methods: MRE data of the brain were acquired with echo-planar imaging (EPI) at 3T (n = 14) and 7T (n = 18). Motion and distortion correction parameters were estimated using the magnitude images.

Nonlinear multiscale regularisation in MR elastography: Towards fine feature mapping.

Unlabelled: Fine-featured elastograms may provide additional information of radiological interest in the context of in vivo elastography. Here a new image processing pipeline called ESP (Elastography Software Pipeline) is developed to create Magnetic Resonance Elastography (MRE) maps of viscoelastic parameters (complex modulus magnitude |G| and loss angle ϕ) that preserve fine-scale information through nonlinear, multi-scale extensions of typical MRE post-processing techniques.

Methods: A new MRE image processing pipeline was developed that incorporates wavelet-domain denoising, image-driven noise estimation, and feature detection.

Tomoelastography by multifrequency wave number recovery from time-harmonic propagating shear waves.

Palpation is one of the most sensitive, effective diagnostic practices, motivating the quantitative and spatially resolved determination of soft tissue elasticity parameters by medical ultrasound or MRI. However, this so-called elastography often suffers from limited anatomical resolution due to noise and insufficient elastic deformation, currently precluding its use as a tomographic modality on its own. We here introduce an efficient way of processing wave images acquired by multifrequency magnetic resonance elastography (MMRE), which relies on wave number reconstruction at different harmonic frequencies followed by their amplitude-weighted averaging prior to inversion.

Real-time 4D phase unwrapping applied to magnetic resonance elastography.

Purpose: Phase amplitude is a source of signal in magnetic resonance elastography (MRE) experiments but its exploitation in experimental design has been limited due to the challenges of phase wrap. This study addressed this aspect of MRE through new developments in algorithms, heuristic strategy, and user interface.

Methods: A test dataset with systematic variation of three parameters-nested wrap, gradient, and noise level-was developed to choose phase-unwrapping algorithms and to analyze their performance.

Statistical mapping of the effect of knee extension on thigh muscle viscoelastic properties using magnetic resonance elastography.

Skeletal muscle viscoelastic properties reflect muscle microstructure and neuromuscular activation. Elastographic methods, including magnetic resonance elastography, have been used to characterize muscle viscoelastic properties in terms of region of interest (ROI) measurements. The present study extended this approach to create thresholded pixel-by-pixel maps of viscoelastic properties of skeletal muscle during rest and knee extension in eleven subjects.