Two-dimensional Tracking Research Articles

Direct Lagrangian method to characterize entrainment dynamics using particle residence time: a case study on a laminar separation bubble

This study demonstrates the feasibility of characterizing small-scale flow dynamics using path-specific Particle Residence Time (PRT). PRT, defined as the time a parcel of fluid spends in a region of interest, is a clear indicator of stagnation and recirculation. To test the concept, two-dimensional particle tracking velocimetry is used to measure a laminar separation bubble (LSB) on the suction side of an SD7003 airfoil at $$Re=60,000$$ . Extended pathlines are calculated from the Lagrangian data such that fluid parcels entering the region of interest are tracked continuously. PRT is then directly calculated and used to quantify the entrainment process across the LSB. Using convential Eulerian quantities, the flow field around the LSB is divided into outer (free stream) and inner layers—separated by the local minimum velocity magnitude line. Entrainment, initiated by the formation of vortices near the reattachment point, is quantified according to the trajectories of fluid parcels crossing into the inner flow layer. The PRT values of entrained fluid parcels are significantly increased compared to the bulk flow. Variations of the mean PRT of entrained fluid reveal unsteady features, including the transition and reattachment of the LSB. The path-dependent indicators of separation, transition and reattachment are shown to closely agree with Eulerian-based benchmark measurements.

Arterial hypertension: a path from unchanged transmitral bloodstream to dysfunction

Objective: assess the parameters characterizing the structural and functional features of the cardiovascular system in patients with arterial hypertension (AH) with signs of diastolic dysfunction of the left ventricle (DDLV), to determine the dynamics of changes in the heart and vessels from the unchanged spectrum of transmitral bloodstream (USTB) to diastolic dysfunction (DD) in AH patients. Material and methods. An open prospective study of patients with essential AH and USTB (n = 34) and with DDLV signs (n = 45) was organized in the state institution «Republican Research Center for Radiation Medicine and Human Ecology». The examined individuals are comparable in terms of sex and age features. Standard transtoracal echocardiography with the determination of standard indices, ultrasonic examination of the extranial department of the brachyocephalic arteries (BCA) with the determination of the thickness of the intima-media complex (CIM), duplex scanning of the arteries of the upper and lower limbs with the determination of the ankle-shoulder index and endothelium-dependent were performed in all the participants of the study. In addition, global longitudinal deformation was evaluated by two-dimensional tracking of the grey spots of the ultrasonic image scale (speckle tracking), parameters of the movement of the fibrous ring of the mitral valve into systole and diastole with the determination of the myocardial index by the method of tissue dopplerography. Results. The examination of the heart by the method of standard transtoracal echocardiography has revealed that AH patients with DDLV (2nd group) in comparison with AH patients with the unchanged spectrum of transmitral bloodstream (1st group) detected higher values of interventricular partition (12 mm versus 9 mm, р = 0.001), relative wall thickness (0.41 versus 0.35, р = 0.033), the index of myocardial mass (65 g versus 58.5 g, р = 0.015). The isovolumetric relaxation time of the PG (81 ms versus 67 ms, p = 0.043), the rate of tricuspidal regurgitation and systolic pressure in the pulmonary artery were significantly higher in the group of AH patients with DDLV (p = 0.005). The analysis of the movement of the fibrous ring of the mitral valve by tissue dopplerography has showed that in the second group of the patients (AH with DDLV), there are signs of regional systolic dysfunction of the medial part of the fibrous ring of the mitral valve (0.08 cm/s versus 0.09, p = 0.047). E/Em was higher in the second group, a statistically significant difference was found for the lateral portion of the fibrous ring of the mitral valve (5.7 vs. 7, p = 0.019). The ultrasonic duplex scanning of the extranial part of the BCA revealed that in the AH patients with DDLV compared to the AH patients with the unchanged spectrum of transmitral bloodstream, the value of the thickness of the CIM is reliably higher (right 0.8 mm versus 0.65 mm, p = 0.001, left 0.8 mm versus 0.7 mm, p = 0.001). The study of the endothelium function has revealed that the second group of the patients compared to the first one, recorded reliably lower values of endothelium dependent vasodilation (10 % versus 14 %, p = 0.009). The analysis of subclinical lesion of the arteries of the lower limbs has revealed that in the group of patients with DDLV compared to the group of the AH patients with the unchanged spectrum of transmitral bloodstream, the ankle-shoulder index value is reliably higher (right 1.1 versus 1.07, p = 0.013, left 1.1 versus 1.07, p = 0.05). Conclusion. The protocol method of research - standard transthoracic echocardiography - does not allow to estimate fully the functional changes of cardiac muscle in AH patients with DDLV in comparison with AH patients with the unchanged spectrum of transmitral bloodstream. The application of additional diagnostic techniques (TDG and speckle tracking) makes it possible to get missing data. Pathologic transformation of transmitral bloodstream occurs when signs of systolic and diastolic dysfunction of the left ventricle already exist. The appearance of signs of diastolic dysfunction of the left ventricle during standard echocardiography is accompanied by pathologic remodeling of the vascular system.

Nanoparticle Tracking to Probe Transport in Porous Media.

From the granular and fractured subsurface environment to highly engineered polymer membranes used in pharmaceutical purification, porous materials are ubiquitous in nature and industrial applications. In particular, porous media are used extensively in processes including water treatment, pharmaceutical sterilization, food/beverage processing, and heterogeneous catalysis, where hindered mass transport is either essential to the process or a necessary but undesirable limitation. Unfortunately, there are currently no universal models capable of predicting mass transport based on a description of the porous material because real porous materials are complex and because many coupled dynamic mechanisms (e.g., adsorption, steric effects, hydrodynamic effects, electrostatic interactions, etc.) give rise to the observed macroscopic transport phenomena.While classical techniques, like nuclear magnetic resonance and dynamic light scattering, provide useful information about mass transport in porous media at the ensemble level, they provide limited insight into the microscopic mechanisms that give rise to complex phenomena such as anomalous diffusion, hindered pore-space accessibility, and unexpected retention under flow, among many others. To address this issue, we have developed refractive index matching imaging systems, combined with single-particle tracking methods, allowing the direct visualization of single-particle motion within a variety of porous materials.In this Account, we summarize our recent efforts to advance the understanding of nanoparticle transport in porous media using single-particle tracking methods in both fundamental and applied scenarios. First, we describe the basic principles for two-dimensional and three-dimensional single-particle tracking in porous materials. Then, we provide concrete examples of nanoparticle transport in porous materials from two perspectives: (1) understanding fundamental elementary particle transport processes in porous media, including pore accessibility and cavity escape, which limit transport in porous media, and (2) facilitating applications in industrial processes, e.g., by understanding the mechanisms of particle fouling and remobilization in filtration membranes. Finally, we provide an outlook of opportunities associated with investigating other types of mass transport in confined environments using single-particle tracking methods, including electrophoretic and self-propelled motion.

Efficient development of vision-based dense three-dimensional displacement measurement algorithms using physics-based graphics models

This research investigates a framework for the efficient development of vision-based dense three-dimensional displacement measurement algorithms to support reliable structural health monitoring of civil structures. The framework exploits the use of a photo-realistic synthetic model, termed a physics-based graphics model, to simulate the entire process of vision-based measurement. At the same time, the synthetic environment is used to evaluate the performance of different post-processing algorithms quantitatively for a given measurement scenario, such as camera selection and camera placement. The effectiveness of the framework is demonstrated by optimizing the algorithms for the three-dimensional displacement measurement of a 14-bay laboratory truss structure. The vision-based dense three-dimensional displacement estimation algorithms optimized in this study consist of four steps: (1) camera parameter estimation, (2) camera motion estimation and compensation, (3) vision-based two-dimensional tracking, and (4) projection of two-dimensional tracking results to three-dimensional space. The algorithms use the knowledge from the finite element model to facilitate the implementation and maximize the measurement outcome, that is, model-informed approach. To test and evaluate the model-informed approach, synthetic videos are rendered for two measurement scenarios, that is, using a Digital Single Lens Reflex camera mounted on a tripod and using an Unmanned Aerial Vehicle camera. Then, the performance of the model-informed approach is evaluated by comparing the estimated displacement with the ground truth values. Based on the performance evaluation, an algorithm with the highest expected performance is selected for each of the two measurement scenarios. Finally, the selected algorithm is tested in a laboratory experiment. In contrast to the existing literature that investigates fixed individual measurement scenarios, the proposed framework can be used to test different measurement scenarios and estimate the outcome of each scenario before performing actual tests, facilitating the implementation of vision-based measurement for the structural health monitoring of civil structures.

Design and implementation of a high efficiency microstrip array antenna for X‐band monopulse tracking applications

In this study, an X-band low-profile monopulse array antenna with high aperture efficiency is proposed for tracking applications. It is consists of a 112-element patch array antenna, a monopulse comparator, and a full corporate feed network which is composed of the waveguide and microstrip dividers. The monopulse comparator and waveguide part of the feed are produced out of a single-layer substrate as the back-end section. Also, the printed array antenna and microstrip part of the feed network are integrated as the front-end. Finally, the back-end and the front-end are integrated through 32 SMP connectors. The proposed design decreases the lateral size of the feed and results in achieving a high level of aperture efficiency. A prototype of the proposed design was manufactured and validated the design experimentally. The measurement results demonstrate that the impedance bandwidth ( ∣ S i i ∣ ⩽ − 12 dB ) is up to 12% with the isolations better than 20 dB. The maximum gain of the sum beam is 28.7 dBi, while the null depths of the difference patterns are better than 24 dB. The excellent characteristics of the proposed design make it a good candidate for two-dimensional monopulse tracking applications at X-band up to millimetre wavelengths.

Effect of Reynolds number on turbulent channel flow over a superhydrophobic surface

The slip boundary and the near-wall statistics of a fully developed turbulent channel flow over a superhydrophobic surface (SHS) was investigated in a low Reynolds number (Re) range. The Re was varied from 6200 to 9400, based on the bulk velocity and the full-channel height. The root-mean-square of the surface roughness, normalized by the inner flow scaling, varied from 0.26 to 0.35 with increasing Re. Time-resolved, two-dimensional particle tracking velocimetry (PTV) was used to obtain the mean velocity profile in the linear viscous sublayer. Furthermore, time-resolved three-dimensional PTV was applied to obtain the Reynolds stresses. The estimated wall shear stress showed that the drag reduction of the SHS increased slightly from 37% to 42% when Re increased. With increasing Re, the slip velocity increased linearly from 0.25 m/s to 0.34 m/s, and the slip length reduced from 97.5 μm to 69.6 µm. When normalized using inner scaling, slip velocity and length remained constant with increasing Re. The mean velocity of the SHS demonstrated a log-law with the universal von Kármán constant but shifted upward by an amount equal to the normalized slip velocity. The SHS increased the dimensional Reynolds stresses in the near-wall region and attenuated them farther away from the wall. With increasing Re, the differences between the dimensional Reynolds stresses of the smooth surface and the SHS increased. However, when Reynolds stresses were normalized using friction velocity, the Reynolds stresses of the SHS overlapped for all the investigated Re and were larger than the normalized Reynolds stresses of the smooth surface.

Haptic Coupling in Dyads Improves Motor Learning in a Simple Force Field.

In dyadic motor learning, pairs of people learn the same motion while their limbs are loosely coupled together using haptic devices. Such coupled learning has been shown to outperform solo learning (including robot-guided learning) for simple one-degree-of-freedom tasks. However, results from more complex tasks are limited and sometimes conflicting. We thus evaluated coupled learning in a two-degree-of-freedom tracking task where participants also had to compensate for a simple force field. Participant pairs were split into two groups: an experiment group that experienced a compliant haptic coupling between participants' hands and a control group that did not. The study protocol consisted of 70 repetitions of 18.9-second tracking trials: 10 initial solo trials with no coupling, 50 "learning" trials (where participants in the experiment group were coupled), and 10 final solo trials with no coupling. The experiment group (coupled) improved their solo tracking performance both in the presence (p = 0.008) and absence (p <; 0.001) of the force field; however, the control group (no coupling) only improved their solo performance in the absence of the force field (p <; 0.001) but not in the presence of the field (p = 0.81). This suggests that dyadic motor learning can outperform solo learning for two-dimensional tracking motions in the presence of a simple force field, though the mechanism by which learning is improved is not yet clear.Clinical Relevance-As motor learning is critical for applications such as motor rehabilitation, dyadic training could be used to achieve a better overall outcome and a faster learning speed in these applications compared to solo training.

Ultrasound-Guided Wireless Tubular Robotic Anchoring System.

Untethered miniature robots have significant poten-tial and promise in diverse minimally invasive medical applications inside the human body. For drug delivery and physical contra-ception applications inside tubular structures, it is desirable to have a miniature anchoring robot with self-locking mechanism at a target tubular region. Moreover, the behavior of this robot should be tracked and feedback-controlled by a medical imaging-based system. While such a system is unavailable, we report a reversible untethered anchoring robot design based on remote magnetic actuation. The current robot prototype's dimension is 7.5 mm in diameter, 17.8 mm in length, and made of soft polyurethane elastomer, photopolymer, and two tiny permanent magnets. Its relaxation and anchoring states can be maintained in a stable manner without supplying any control and actuation input. To control the robot's locomotion, we implement a two-dimensional (2D) ultrasound imaging-based tracking and control system, which automatically sweeps locally and updates the robot's position. With such a system, we demonstrate that the robot can be controlled to follow a pre-defined 1D path with the maximal position error of 0.53 ± 0.05 mm inside a tubular phantom, where the reversible anchoring could be achieved under the monitoring of ultrasound imaging.

Case studies on the effect of two-dimensional heliostat tracking on the performance of domestic scale solar thermal tower

Solar thermal system has been envisioned for utility scale applications. However, on the low end the domestic applications can be made realizable through low end automation. Performance of typical solar reflector can be significantly enhanced by using a solar tracking system. An efficient & low energy consuming system can result in improved energy harvesting. In the current study, an experimental analysis of automated domestic scale heliostat field using rack and pinion-based mechanism is performed. The mechanism is controlled using relay module with an Arduino UNO R3-SMD. Experiments are performed in actual working conditions of Taxila, Pakistan. The heliostat field is made to reflect the solar rays to a cavity type central receiver (CTCR) having stainless steel tubing. Experimentations were performed under three different scenarios-tracking using one dimensional (1D) with fixed position heliostats, tracking using two dimensional (2D) with 5 variable positioning heliostats, and tracking using 2D with 8 variable positioning heliostats. The performances of each setup is analyzed parameters such as heating fluid, temperature difference (ΔT), absorbed heat (Qabs), and overall efficiency (ƞ). Performance enhancement was observed using 2D tracking with 8 variable positioning heliostats where ΔT was 64.26 °C, Qabs was 489.89 W, with maximum ƞ was 52.8%. In 2D with 5 variable positioning heliostats and 1D with fixed heliostats, the values obtained were 50.3 °C, 385.5 W, 51.83% and 6.523 °C, 50 W, 45.86% respectively.

Heart Infection Prognosis Analysis by Two-dimensional Spot Tracking Imaging.

Cardiovascular death is one of the leading causes worldwide; an accurate identification followed by diagnosing the cardiovascular disease increases the chance of a better recovery. Among different demonstrated strategies, imaging on cardiac infections yields a visible result and highly reliable compared to other analytical methods. Two-dimensional spot tracking imaging is the emerging new technology that has been used to study the function and structure of the heart and test the deformation and movement of the myocardium. Particularly, it helps to capture the images of each segment in different directions of myocardial strain values, such as valves of radial strain, longitudinal strain, and circumferential strain. In this overview, we discussed the imaging of infections in the heart by using the two-dimensional spot tracking.

Particle Residence Time in pulsatile post-stenotic flow

Particle Residence Time (PRT), a measure of a fluid element’s transit time through a region of interest, is a clear indicator of recirculation. The PRT of fluid recirculating downstream of an idealized stenosis geometry is found to vary dramatically under pulsatile flow conditions. Two-dimensional particle tracking velocimetry is used to track particles directly as they exit the stenosis geometry and are entrained into the region of recirculation immediately downstream. A Lagrangian approach permits long pathlines to be drawn, describing each particle’s motion from the instant they enter the domain. PRT along each pathline is compared here for three mean Reynolds numbers; specifically, Rem = 4800, 9600, and 14 400. The pulsatile waveforms are characterized by Strouhal numbers of 0.04, 0.08, and 0.15 and amplitude ratios of 0.50 and 0.95. As the mean Reynolds number is increased, higher fluid velocities are shown to lower PRT. However, the strength of PRT is truly revealed when highlighting the influence pulsatility has on the degree of mixing beyond the stenosis throat. Higher Strouhal numbers correlate with roll-up across the shear layer and increased PRT distribution at all Reynolds numbers in consideration. Similarly, strong temporal velocity gradients generated by a high amplitude ratio carry large volumes of fluid from the jet deep into the recirculation region, contributing to greater PRT.

Structural and Functional Features of the Cardiovascular System in Arterial Hypertension with Normal Spectrum of Transmitral Blood Flow

Objective: to assess the structural and functional features of the cardiovascular system in patients with arterial hypertension (AH) and normal spectrum of transmitral blood flow (NSTBF). Material and methods. An open prospective study of patients with essential hypertension (n=31) and healthy volunteers (n = 10) was organized at the state institution «Republican Research Center for Radiation Medicine and Human Ecology». The examined individuals were comparable in terms of sex and age features. All the participants of the study underwent transthoracic echocardiography (EchoCG) with the determination of the standard parameters, ultrasound of the extracranial part of the brachiocephalic arteries (BCA) with the determination of the thickness of the intima-media complex (CIM) and carotid plaques, duplex scanning of the arteries of the upper and lower extremities with the measurement of the ankle-brachial index (LPI) and endothelium-dependent vasodilation (EDVD). In addition, we assessed the global longitudinal deformation by the method of two-dimensional speckle tracking of the gray spots of the ultrasound image, the indicators of the movement of the fibrous ring of the atrioventricular valves into systole and diastole with the determination of the myocardial index by tissue dopplerography (TDG).Results. In comparison with the healthy volunteers, the patients with AH and NSTB have detected reliable changes in the anteroposterior size (38 mm versus 32.5 mm; p = 0.001) and volume (45 ml versus 31.5 ml; p = 0.002) of the left atrium (LP) and volume (37.5 ml versus 29.5 ml, p = 0.005) of the right atrium (PP), measured by means of standard transthoracic echocardiography. Using the method of two-dimensional tracking of the speckle spots of the gray scale of the ultrasound image we have recorded lower values of the global longitudinal strain (-17.5 versus -21.6; p &lt; 0.001) in the study group compared with the control group, which indicates a violation of the biomechanics of the myocardial contractions of the left ventricle (LV). The study of the movement of the fibrous rings of the atrioventricular valves using tissue dopplerography (TDG) has showed that in the second group of the patients there are regional disorders of diastolic function, primarily this concerns the medial part of FC MK (1.3 versus 1.1; p = 0.05) and the lateral part of FC TC (1.3 versus 0.8; p = 0.028). In addition, in comparison with the healthy individuals we recorded higher values of the myocardial index for the lateral (0.51 versus 0.43; p = 0.001) and medial parts (0.59 versus 0.44; p = 0.001) FC MK, lateral part (0.58 versus 0.44; p = 0.001) FC TC. The patients of the study group, in comparison with the control one, have revealed signs of the pathological remodeling of the vascular wall. In the first group of the examined individuals, in comparison with the second one, the thickness of the intima-media complex (CIM) was slightly higher (p = 0.061 on the right, p = 0.08 on the left) and cases of the presence of atherosclerotic plaques (ASB) were recorded.Conclusion. The protocol research methods do not allow the comprehensive evaluation of the functional features of the heart in patients with AH, which requires additional diagnostic methods: TDH and speckle tracking.

One time‐step particle smoothing for radio range‐based indoor position tracking

In the context of sequential estimation of radio range-based indoor position tracking, Bayesian smoothing framework is promising as involving past, present and future observations. The performance and practicability of a smoothing method greatly depend on how many and how future observations are incorporated. Aiming at real-time locating systems, the authors propose one time-step smoothing form on sequential Monte Carlo methods, including four popular Bayesian smoothers and a novel one time-step smoothed filtering (SF) algorithm. The smoothing algorithms are evaluated through two-dimensional position tracking on a real-world indoor test-bed. The authors present results that the proposed SF improves tracking performance requiring very limited computation and memory, which is applicable for real-time indoor position tracking. Moreover, the one time-step smoothing form is validated to mitigate ranging errors and smooth positioning trajectories.

Arrangement Effects of 30 deg Inclined Teardrop-Shaped Dimples on Film Cooling Flow Over Dimpled Cutback Surface at Airfoil Trailing Edge Investigated by 2D3C-PTV

Abstract The objective of this study is to determine the differences in flow fields between the 30 deg in-line and staggered arrangements of teardrop-shaped dimples, and to explain why the surface-averaged Nusselt number with the 30 deg in-line arrangement was 28.7% higher than that with the 30 deg staggered arrangement in our previous study. Measurements of the instantaneous velocity fields over the dimpled cutback surfaces in the two arrangements were performed at five spanwise cross sections using two-dimensional three-component particle tracking velocimetry (2D3C-PTV). Recirculation flows were observed only inside the dimples in the in-line arrangement, and the region above the recirculation flows exhibited a higher Reynolds shear stress. In this region, turbulent mixing between the high-speed cooling-flow and the low-speed recirculation-flow can be promoted. Streamlines of the time-averaged velocities showed that approximately half the fluid flowing out of a teardrop-shaped dimple in the in-line arrangement hardly flowed into the ones downstream. The remainder of the fluid mostly flowed into the dimple immediately downstream, and the inflow of the fluid into further downstream dimples decreased gradually. From the PTV results, we can deduce that the fluid motions in the in-line arrangement leads to a larger temperature-difference between the dimple wall and the fluid because the inflow of fluid heated inside upstream dimples into the downstream ones is less than in the staggered arrangement. Consequently, the Nusselt number in the in-line arrangement was higher.

Interrelation between midwall mechanics and longitudinal strain in newly diagnosed and never-treated hypertensive patients without clinically defined hypertrophy.

In hypertensive patients, an impairment of midwall myocardial mechanics was described in presence of left ventricular (LV) concentric geometry. Under these circumstances, also LV longitudinal dysfunction was found. Our aim was to evaluate longitudinal and circumferential systolic function and correlations between these two functional components in newly diagnosed hypertensive patients without clinically defined LV hypertrophy (LVH). One hundred and thirty-eight newly diagnosed, never-treated hypertensive patients without LVH and a control group of 105 healthy normotensive individuals underwent two-dimensional and speckle tracking echocardiography. Global longitudinal strain (GLS) was derived (in absolute value) and midwall fractional shortening (MFS) computed. In addition, the hypertensive population was divided into two groups according to GLS: normal GLS (≥20%, n = 94) and reduced GLS (<20%, n = 44). Hypertensive patients had lower MFS (P < 0.001) and GLS (P < 0.0001) than healthy controls. By dividing hypertensive patients according to GLS thresholds of normalcy, MFS was lower in patients with GLS less than 20% (P < 0.0001) while no significant difference was found in LV geometry, ejection fraction and diastolic parameters in comparison with patients with GLS at least 20%. In the pooled hypertensive population, GLS resulted positively related to MFS (r = 0.33, P < 0.0001). By a multiple linear regression analysis, after adjusting for female sex, age, BMI, circumferential end-systolic stress, average e', ejection fraction and relative wall thickness, MFS remained independently associated with GLS (β = 0.222, P < 0.005). In newly diagnosed and never-treated hypertensive patients without LVH, an early LV systolic dysfunction is testified by the reduction of both MFS and GLS. These two parameters resulted independently associated after adjusting for several confounders.

Left Ventricular Myocardial Function in a Cat with Nonspecific Cardiomyopathy Phenotype

Background: Non-specific phenotype feline cardiomyopathy (CFNE) is one that does not fit properly in the other categories, and it is necessary to describe in detail the morphology and cardiac function. The causes of CFNE is not very clear, and it may be due to congenital or acquired disease, or also to primary or secondary myocardial dysfunction associated with other conditions. In symptomatic cases, the clinical signs observed are compatible with left congestive heart failure (ICCE). This study reports a CFNE case in an asymptomatic cat, in order to demonstrate the importance of echocardiographic examination in the early diagnosis of the disease.Case: A 6.5-year-old non-neutered crossbred cat weighing 3.1 kg was seen at the institution's veterinary hospital for routine cardiac evaluation. No clinical signs were reported in the history. On physical examination, the animal presented calm behavior, body score 5/9, heart rate 200 bpm, systolic blood pressure of 102 mmHg, respiratory rate 64 mrp, and other normal parameters. CBC and urinalysis laboratory tests were requested, which were unchanged. The electrocardiogram showed normal patterns. In the conventional echocardiographic examination, a significant increase in the left atrium (LA) was observed, and the LA/Ao ratio was 2.05 and the diastolic function was abnormal. There was no presence of concentric hypertrophy of the left ventricle (LV), the thickness of the ventricular wall measured at different points, in the two-dimensional mode and the M mode, was less than 5 millimeters. Other parameters of conventional echocardiography were within the normal range. Through these echocardiographic findings, the suggestive diagnosis was non-specific phenotype cardiomyopathy, with a significant increase in LA. For the assessment of left ventricular myocardial deformation, the strain (St%) and strain rate (StR 1/s) indexes (which correspond to the percentage and speed at which the myocardial fiber deforms during the cardiac cycle, respectively) were evaluated using two-dimensional feature tracking (2D-FTI), with the aid of Xstrain version 10.1 software, optical flow algorithm (ESAOTE®). This analysis showed a decrease in the overall value of the longitudinal and radial St/StR variables.Discussion: The CFNE echocardiographic examination can demonstrate several structural cardiac changes that are not characterized in any other category of cardiomyopathy. Although the patient is still asymptomatic, the echocardiogram made it possible to identify structural changes compatible with the reported disease (enlargement of the left atrium and left ventricular myocardial deformation). Using the 2D-FTI technique, the vulnerability of the myocardial fibers in the longitudinal and radial directions of the left ventricle was observed, demonstrating that despite the patient still not showing clinical signs, there were already signs of ventricular dysfunction. These changes observed by the 2D-FTI technique, suggest that the patient may develop clinical signs of ICCE, resulting from pleural effusion and/or pulmonary edema, requiring more frequent reassessments. For this reason, animals with CFNE should undergo periodic cardiac evaluation to monitor the evolution of the patient's clinical condition. The use of more specific tools, such as 2D-FTI, allows an earlier assessment of clinical changes, which provides a faster therapeutic intervention when necessary, preventing the patient from abruptly decompressing.

Underwater Target Tracking Control of an Untethered Robotic Fish With a Camera Stabilizer

Implementing underwater target tracking remains difficult for a free-swimming robotic fish owing to the intrinsically reciprocating motion in fishlike propulsion. In this article, we present a novel robotic fish platform with a camera stabilizing system and achieve real-time two-dimensional target tracking assisted by reinforcement learning (RL) in continuous environments. More specifically, we first develop an active visual tracking system based on cascade control structure to obtain the relative orientation between the robotic fish and the underwater target. Then, we propose a target tracking controller dealing with continuous state and action spaces based on deep RL (DRL). The controller takes the position of the target object as input and yields the motion parameters of the bioinspired central pattern generator governed robotic fish. The robustness and adaptability of the proposed controller as well as the influence of time-delays on the control system are explored via simulated experiments under different scenarios. Finally, both static and dynamic tracking experiments on the actual robotic fish demonstrate the effectiveness of the proposed mechatronic design and control methods, providing insights to executing aquatic vision-based tracking tasks.

Three-Dimensional Automated Volume Calculation (Sonography-Based Automated Volume Count) versus Two-Dimensional Manual Ultrasonography for Follicular Tracking and Oocyte Retrieval in Women Undergoing in vitro Fertilization-Embryo Transfer: A Randomized Controlled Trial.

Aim:To compare the oocyte yield using three-dimensional (3D) automated and two-dimensional (2D) ultrasound-based follicle tracking in women undergoing in vitro fertilization-embryo transfer (IVF-ET).Settings and Design:A randomized controlled trial was conducted in the Reproductive Medicine Unit of a teaching medical institute from January 2017 to December 2018.Materials and Methods:A total of 130 patients undergoing IVF-ET were enrolled and randomized into two groups (65 patients in each group). In Group A, follicular tracking during controlled ovarian stimulation (COS) was done using 3D Sonography- based Automated Volume Count (SonoAVC), whereas in Group B, follicular tracking was done by manual ultrasonography (2D USG). The primary outcome measures were the number of oocytes retrieved (the total number and the number of mature oocytes). Secondary outcomes were fertilization rate, cleavage rate, total number of embryos and time taken to perform scans. Other outcome measures were clinical pregnancy rate, miscarriage rate and live birth rate (LBR).Statistical Analysis Used:Chi-square test, Student's t-test, Z-test, Wilcoxon rank-sum test, Bland–Altman's plot.Results:The two groups were comparable with regard to assisted reproductive technology (ART) outcomes. Group B required more time for performing the scan (P < 0.01).Conclusion:Automated SonoAVC ultrasound can be used interchangeably with manual 2D USG for follicle tracking during COS giving comparable ART outcomes with the added advantage of saving time. Our study implies the promising results of applying artificial intelligence in follicular tracking during COS.

An Input Power-Aware Efficiency Tracking Technique With Discontinuous Charging for Energy Harvesting Applications

This paper proposes a discontinuous charging technique for switched-capacitor converters that improves the power conversion efficiency (PCE) at low power levels and extends the input power harvesting range at which high PCE is achievable. Discontinuous charging delivers current to energy storage only during clock non-overlap time. This enables tuning of the output current to minimize converter losses based on the available input power. Based on this fundamental result, an input power-aware, two-dimensional efficiency tracking technique for Wireless Sensor Network (WSN) nodes is presented. In addition to conventional switching frequency control, clock non-overlap time control is introduced to adaptively optimize PCE according to the sensed ambient power levels. The proposed technique is designed and simulated in 90nm CMOS with post-layout extraction. Under the same input and output conditions, the proposed system maintains at least 45% PCE at 4μW input power, as opposed to a conventional continuous system which requires at least 18.7μW to maintain the same PCE. Therefore, the input power harvesting range is extended by 1.5x. The technique is applied to a wearable WSN implementation utilizing the IEEE 802.15.4-compatible GreenNet communications protocol. This allows the node to meet specifications and achieve energy autonomy when deployed in environments where the input power is 49% lower than what is required for conventional operation.

Fast Accurate Beam and Channel Tracking for Two-Dimensional Phased Antenna Arrays

The sparsity and the severe attenuation of millimeter-wave (mmWave) channel imply that highly directional communication is needed. The narrow beam produced by large array requires accurate alignment, which is difficult to achieve when serving fast-moving users. In this paper, we focus on accurate two-dimensional (2D) beam and channel tracking problem aiming at minimizing exploration overhead and tracking error. Using a typical frame structure with periodic exploration and communication, a proven minimum overhead of exploration is provided first. Then tracking algorithms are designed for three types of channels with different dynamic properties. It is proved that the algorithms for quasi-static channels and channels in Dynamic Case I are optimal in approaching the minimum Cramer-Rao lower bound (CRLB). The computational complexity of our algorithms is analyzed showing their efficiency, and simulation results verify their advantages in both tracking error and tracking speed.