Synchronization of Unified Chaotic Systems Using Sliding Mode Controller

This paper presents a method for synchronizing the unified chaotic systems via a sliding mode controller (SMC). The unified chaotic system and problem formulation are described. Two identical unified chaotic systems can be synchronized using the SMC technique. The switching surface and its controller design are developed in detail. Simulation results show the feasibility of a chaotic secure communication system based on the synchronization of the Lorenz circuits via the proposed SMC

Effect of negative pressure therapy on the treatment response to scar thickness and viscoelasticity

Patients with scars face a grave threat to their mental and physical health. Negative pressure has been used for scar therapy in medical care and provides a microenvironment conducive to scar healing while stimulating cell regeneration. Negative pressure may disrupt scar tissue regeneration when the pressure is too high or too low, so finding a suitable negative pressure is important. We hypothesized that different negative pressure magnitudes would affect scar tissue properties differently. This research aimed to provide practical recommendations for scar therapy. This study used three negative pressures (−105 mmHg, −125 mmHg, and −145 mmHg) to compare scar material properties. We measured scar tissue thickness and viscoelasticity with a motor-driven ultrasound indentation system. According to the results of this study, scar thickness is most effectively reduced at a negative pressure of −105 mmHg. In comparison, scar viscoelasticity continuously increases at a negative pressure of −125 mmHg. Negative pressure therapy can be recommended to scar care clinics based on the results of this study

An approach to the diagnosis of lumbar disc herniation using deep learning models

Background: In magnetic resonance imaging (MRI), lumbar disc herniation (LDH) detection is challenging due to the various shapes, sizes, angles, and regions associated with bulges, protrusions, extrusions, and sequestrations. Lumbar abnormalities in MRI can be detected automatically by using deep learning methods. As deep learning models gain recognition, they may assist in diagnosing LDH with MRI images and provide initial interpretation in clinical settings. YOU ONLY LOOK ONCE (YOLO) model series are often used to train deep learning algorithms for real-time biomedical image detection and prediction. This study aims to confirm which YOLO models (YOLOv5, YOLOv6, and YOLOv7) perform well in detecting LDH in different regions of the lumbar intervertebral disc.Materials and methods: The methodology involves several steps, including converting DICOM images to JPEG, reviewing and selecting MRI slices for labeling and augmentation using ROBOFLOW, and constructing YOLOv5x, YOLOv6, and YOLOv7 models based on the dataset. The training dataset was combined with the radiologist’s labeling and annotation, and then the deep learning models were trained using the training/validation dataset.Results: Our result showed that the 550-dataset with augmentation (AUG) or without augmentation (non-AUG) in YOLOv5x generates satisfactory training performance in LDH detection. The AUG dataset overall performance provides slightly higher accuracy than the non-AUG. YOLOv5x showed the highest performance with 89.30% mAP compared to YOLOv6, and YOLOv7. Also, YOLOv5x in non-AUG dataset showed the balance LDH region detections in L2-L3, L3-L4, L4-L5, and L5-S1 with above 90%. And this illustrates the competitiveness of using non-AUG dataset to detect LDH.Conclusion: Using YOLOv5x and the 550 augmented dataset, LDH can be detected with promising both in non-AUG and AUG dataset. By utilizing the most appropriate YOLO model, clinicians have a greater chance of diagnosing LDH early and preventing adverse effects for their patients

Complexity-Based Measures of Postural Sway during Walking at Different Speeds and Durations Using Multiscale Entropy

[[abstract]]Participation in various physical activities requires successful postural control in response to the changes in position of our body. It is important to assess postural control for early detection of falls and foot injuries. Walking at various speeds and for various durations is essential in daily physical activities. The purpose of this study was to evaluate the changes in complexity of the center of pressure (COP) during walking at different speeds and for different durations. In this study, a total of 12 participants were recruited for walking at two speeds (slow at 3 km/h and moderate at 6 km/h) for two durations (10 and 20 min). An insole-type plantar pressure measurement system was used to measure and calculate COP as participants walked on a treadmill. Multiscale entropy (MSE) was used to quantify the complexity of COP. Our results showed that the complexity of COP significantly decreased (p < 0.05) after 20 min of walking (complexity index, CI = −3.51) compared to 10 min of walking (CI = −3.20) while walking at 3 km/h, but not at 6 km/h. Our results also showed that the complexity index of COP indicated a significant difference (p < 0.05) between walking at speeds of 3 km/h (CI = −3.2) and 6 km/h (CI = −3.6) at the walking duration of 10 min, but not at 20 min. This study demonstrated an interaction between walking speeds and walking durations on the complexity of COP. View Full-Tex

A comparative study of the effects of electrical stimulation and intermittent compressive forces on soft tissue mechanical properties

[[abstract]]We aimed to investigate and compare the effects of electrical stimulation and intermittent compressive forces on soft tissue mechanical properties. Four healthy individuals were recruited into this study. A transcutaneous electrical stimulation device was used to apply a pulse duration of 2.5 ms, a frequency of 2 Hz, and the amplitude to a maximum of 30 mA. The intermittent compressive forces were applied at a period of 20 s with forces ranging from 0 to 70 mmHg. The effective Young’s modulus was calculated to characterize mechanical properties of forearm soft tissues. The results showed that forearm soft tissue properties might decrease effective Young’s modulus after the treatments of electrical stimulation and intermittent compressive forces.[[abstract]]We aimed to investigate and compare the effects of electrical stimulation and intermittent compressive forces on soft tissue mechanical properties. Four healthy individuals were recruited into this study. A transcutaneous electrical stimulation device was used to apply a pulse duration of 2.5 ms, a frequency of 2 Hz, and the amplitude to a maximum of 30 mA. The intermittent compressive forces were applied at a period of 20 s with forces ranging from 0 to 70 mmHg. The effective Young’s modulus was calculated to characterize mechanical properties of forearm soft tissues. The results showed that forearm soft tissue properties might decrease effective Young’s modulus after the treatments of electrical stimulation and intermittent compressive forces

Hardware Implementation of Lorenz Circuit Systems for Secure Chaotic Communication Applications

This paper presents the synchronization between the master and slave Lorenz chaotic systems by slide mode controller (SMC)-based technique. A proportional-integral (PI) switching surface is proposed to simplify the task of assigning the performance of the closed-loop error system in sliding mode. Then, extending the concept of equivalent control and using some basic electronic components, a secure communication system is constructed. Experimental results show the feasibility of synchronizing two Lorenz circuits via the proposed SMC

Using Cross-Correlation Function to Assess Dynamic Cerebral Autoregulation in Response to Posture Changes for Stroke Patients

Abstract In this study, time-domain cross-correlation function was applied to evaluate the relationship between blood pressure and cerebral blood flow velocity signals acquiring from healthy subjects and stroke patients both in supine and head-up tilt positions to evaluate the effect of posture change. 10 stroke patients and 11 healthy subjects were included in this study. Results revealed that the mean arterial blood pressure (MABP) values of stroke patients in response to posture changes were reduced. However, MABP values in healthy subjects were become higher in head-up tilt position. Both of MABP values of healthy subjects in supine and head-up tilt were significantly lower than those in stroke patients (p&lt; 0.05). On the other hand, mean cerebral blood flow velocity (MCBFV) in healthy subjects remain constant. However, the values in stroke patients reduced in response to headup tilt. In the results of cross-correlation function (CCF) analysis, max CCF values in healthy subjects were significantly higher than those in stroke patients (p&lt; 0.05) in both supine and head-up tile positions. It might indicate correlation of MABP and MCBFV was higher in healthy subjects. The max CCF index in stroke patients were close to 0 second in both positions (supine: -0.35±3.36 sec; head-up tilt: -0.29±3.20 sec). In healthy subjects, max CCF values should be around 2 seconds. Hence, it indicated the phase difference almost did not exist between MABP and MCBFV. This reveals the buffer function of CA were lower in stroke patients. Therefore, CA in stroke patients might be impaired by the results in response to posture changes

Using Elastographic Ultrasound to Assess Plantar Tissue Stiffness after Walking at Different Speeds and Durations

Exercise has been demonstrated to improve health in people with diabetes. However, exercise may increase risk for foot ulcers because of increased plantar pressure during most weight-bearing physical activities. To date, there is no study investigating the effect of various walking speeds and durations (i.e., the most common form of exercise in daily living) on the plantar foot. The objective of this study was to investigate the effect of various walking intensities on plantar tissue stiffness. A 3 &times; 2 factorial design, including three walking speeds (1.8, 3.6 and 5.4 mph) and two durations (10 and 20 min), was tested in 12 healthy participants. B-mode and elastographic ultrasound images were measured from the first metatarsal head to quantify plantar tissue stiffness after walking. Two-way ANOVA was used to examine the results. Our results showed that the walking speed factor caused a significant main effect of planar stiffness of the superficial layers (p = 0.007 and 0.003, respectively). However, the walking duration factor did not significantly affect the plantar stiffness. There was no interaction between the speed and duration factors on plantar tissue stiffness. Regarding the walking speed effect, there was a significant difference in the plantar stiffness between 1.8 and 3.6 mph (56.8 &plusmn; 0.8% vs. 53.6 &plusmn; 0.9%, p = 0.017) under 20 min walking duration. This finding is significant because moderate-to-fast walking speed (3.6 mph) can decrease plantar stiffness compared to slow walking speed (1.8 mph). This study suggests people at risk for foot ulcers walk at a preferred or fast speed (3.6 mph) rather than walk slowly (1.8 mph)