Molecular Imaging of Pulmonary Tuberculosis in an Ex-Vivo Mouse Model Using Spectral Photon-Counting Computed Tomography and Micro-CT

Assessment of disease burden and drug efficacy is achieved preclinically using high resolution micro computed tomography (CT). However, micro-CT is not applicable to clinical human imaging due to operating at high dose. In addition, the technology differences between micro-CT and standard clinical CT prevent direct translation of preclinical applications. The current proof-of-concept study presents spectral photon-counting CT as a clinically translatable, molecular imaging tool by assessing contrast uptake in an ex-vivo mouse model of pulmonary tuberculosis (TB). Iodine, a common contrast used in clinical CT imaging, was introduced into a murine model of TB. The excised mouse lungs were imaged using a standard micro-CT subsystem (SuperArgus) and the contrast enhanced TB lesions quantified. The same lungs were imaged using a spectral photoncounting CT system (MARS small-bore scanner). Iodine and soft tissues (water and lipid) were materially separated, and iodine uptake quantified. The volume of the TB infection quantified by spectral CT and micro-CT was found to be 2.96 mm(3) and 2.83 mm(3), respectively. This proof-of-concept study showed that spectral photon-counting CT could be used as a predictive preclinical imaging tool for the purpose of facilitating drug discovery and development. Also, as this imaging modality is available for human trials, all applications are translatable to human imaging. In conclusion, spectral photon-counting CT could accelerate a deeper understanding of infectious lung diseases using targeted pharmaceuticals and intrinsic markers, and ultimately improve the efficacy of therapies by measuring drug delivery and response to treatment in animal models and later in humans

Features of heart rate variability in young people, associated with body weight

The aim of the research was to study the characteristics of heart rate variability (HRV) criteria to detect early vegetative imbalance in young people with overweight and obesity. From 163 students with an average age of 22,2 years were conducted to study the quality of life, аnthropometry, bioimpedance test, HRV at 10-minute intervals. In the normal range of integral indicator HRV - tension index (TI) - with rising TI grew sympathetic activation and decreased the overall HRV and parasympathetic activity. Young people with increased visceral fat recorded higher values in systolic and diastolic blood pressure and TI. The level of visceral fat has determinating effect on the sympatho-vagal balance, modulation which reliably reflects indicator HRV - TI

Preventive potential of bioimpedancmetria and heart rate variability methods in ambulatory practice

The article describes the use of techniques bioimpedancmetria and heart rate variability (HRV) among young people to identify early functional changes in the composition of the composite body and the vegetative regulation of heart rhythm associated with physical activity (PA), body weight and stress. Determined a high prevalence of low PA (45,2%), overweight and obesity (41,0%). The level of visceral fat is an early indicator of overweight and obesity, low PA, high levels of stress and increased sympathetic activity of the autonomic nervous system

MARKERS OF ADAPTATION TO PHYSICAL LOADS IN YOUNG PEOPLE COMMITTED TO HEALTHY LIFESTYLE

The aim was to study the gender characteristics of the heart rate variability (HRV) in young people depending on physical loading (FL), associated with habitual physical activity (FA).Materials and methods. 98 practically healthy students of a medical high school with different levels of habitual FA were examined. HRV was studied at short 10-minute intervals at rest and after intense FL with the energy consumption of 72–88 kcal.Results. HRV changes are determined, which depend not only on the FL intensity and the training level of young people, but are also gender-associated. At rest, less pronounced sympathetic tone (LF/HF 0.86±0.04 versus 1.05±0.04, p<0.05) and the predominance of the central mechanisms of the heart rhythm over the autonomous ones (ID 75.3±5.7 versus 55.8±5.5 units, p<0.05) were observed for female respondets as compared to the young men. After intense FL, a more pronounced inhibition of the parasympathetic tone (pNN (50%) 5.4±1.2 vs. 10.2±1.9%, p<0.05) and a more pronounced functional intensity of adaptive reactions (ID 176.6±17.9 against 101.4±14.4 units, p<0.05) were noted for the female respondetns as well.Conclusion. Changes in HRV parameters, which reflect the beneficial effects of physical training on the adaptive responses of the cardiovascular system, have been found in young people with constant, habitually high FA. The application of the HRV research methodology for short periods in dynamics is justified in the practice of health-saving preventive and rehabilitation measures, since it allows the process of optimal adaptation of a person to physical loading to be controlled.Conflict of interest: the authors declare no conflict of interest

A transition from parabolic to conical shape as a common effect in nearby AGN jets

Observational studies of collimation in jets in active galactic nuclei (AGN) are a key to understanding their formation and acceleration processes. We have performed an automated search for jet shape transitions in a sample of 367 AGN using VLBA data at 15 and 1.4 GHz. This search has found 10 out of 29 nearby jets at redshifts z < 0.07 with a transition from a parabolic to conical shape, while the full analysed sample is dominated by distant AGN with a typical z ≈ 1. The ten AGN are UGC 00773, NGC 1052, 3C 111, 3C 120, TXS 0815−094, Mrk 180, PKS 1514+00, NGC 6251, 3C 371, and BL Lac. We conclude that the geometry transition may be a common effect in AGN jets. It can be observed only when sufficient linear resolution is obtained. Supplementing these results with previously reported shape breaks in the nearby AGN 1H 0323+342 and M87, we estimate that the break occurs at 10 5–10 6 gravitational radii from the nucleus. We suggest that the jet shape transition happens when the bulk plasma kinetic energy flux becomes equal to the Poynting energy flux, while the ambient medium pressure is assumed to be governed by Bondi accretion. In general, the break point may not coincide with the Bondi radius. The observational data support our model predictions on the jet acceleration and properties of the break point.Peer reviewe

A hybrid 2D/3D user interface for radiological diagnosis

This paper presents a novel 2D/3D desktop virtual reality hybrid user interface for radiology that focuses on improving 3D manipulation required in some diagnostic tasks. An evaluation of our system revealed that our hybrid interface is more efficient for novice users and more accurate for both novice and experienced users when compared to traditional 2D only interfaces. This is a significant finding because it indicates, as the techniques mature, that hybrid interfaces can provide significant benefit to image evaluation. Our hybrid system combines a zSpace stereoscopic display with 2D displays, and mouse and keyboard input. It allows the use of 2D and 3D components interchangeably, or simultaneously. The system was evaluated against a 2D only interface with a user study that involved performing a scoliosis diagnosis task. There were two user groups: medical students and radiology residents. We found improvements in completion time for medical students, and in accuracy for both groups. In particular, the accuracy of medical students improved to match that of the residents

Ferromagnetism of MnxSi1-x(x ∼ 0.5) films grown in the shadow geometry by pulsed laser deposition method

The results of a comprehensive study of magnetic, magneto-transport and structural properties of nonstoichiometric MnxSi1-x (x ≈ 0.51-0.52) films grown by the Pulsed Laser Deposition (PLD) technique onto Al2O3(0001) single crystal substrates at T = 340°C are present. A highlight of used PLD method is the non-conventional (“shadow”) geometry with Kr as a scattering gas during the sample growth. It is found that the films exhibit high-temperature (HT) ferromagnetism (FM) with the Curie temperature TC ∼ 370 K accompanied by positive sign anomalous Hall effect (AHE); they also reveal the polycrystalline structure with unusual distribution of grains in size and shape. It is established that HT FM order is originated from the bottom interfacial self-organizing nanocrystalline layer. The upper layer adopted columnar structure with the lateral grain size ≥50 nm, possesses low temperature (LT) type of FM order with Tc ≈ 46 K and contributes essentially to the magnetization at T ≤ 50 K. Under these conditions, AHE changes its sign from positive to negative at T ≤ 30K. We attribute observed properties to the synergy of distribution of MnxSi1-x crystallites in size and shape as well as peculiarities of defect-induced FM order in shadow geometry grown polycrystalline MnxSi1-x (x ∼ 0.5) films