Search

A novel 3D chaotic oscillator that incorporates quadratic and absolute-function nonlinearities is introduced in this paper. The system dynamics are explored using the Lyapunov direct method, phase plane trajectories, time response, Lyapunov exponents, bifurcation diagrams, and basins of attraction. The uniqueness and existence of the system solution have been proven. The analytical investigations show that the system has two stable equilibrium points along with one unstable equilibrium point and a line of equilibria. The positive half of this line represents unstable equilibria, while the negative half is associated with stable equilibria. Additionally, it is found that the oscillator exhibits a chaotic basin of attraction centered along the line of equilibria and surrounded by a fixed-point attractor. An electronic circuit using Multisim software is designed to demonstrate the possibility of physical implementation for the considered mathematical model. Chaos control is addressed using adaptive and sliding mode control strategies. The performance of both control methods is compared, with the sliding mode control demonstrating superior results in both fast response and small transient overshoot. Furthermore, a novel sliding mode controller for master–slave synchronization is introduced, showing high performance compared to other sliding-mode and adaptive control methods applied in the literature. Finally, the proposed oscillator is employed as a Pseudo Random Number Generator (PRNG) for image encryption applications using a new encryption model. The experimental results confirm the high security and robustness of the proposed encryption algorithm against various attack methods. [ABSTRACT FROM AUTHOR]

Background To compare the effectiveness of ES and TS plus exercise breathing after discharge on mechanically ventilated patients with chronic obstructive pulmonary disease (COPD) to those receiving standard care in terms of 30-day mortality, hospital readmission, and health-related quality of life (HRQOL). Patients and methods The current study was a randomized controlled trial. It included 108 newly admitted patients with COPD to RICU, Chest Department, Assiut University Hospital, Egypt, between June 2018 and May 2020. They were divided into two groups: group I received the usual care plus ES and TS plus breathing exercise, and group II received the usual care alone. Thirty-day mortality, hospital readmission, and HRQOL assessed by MFR-28 were recorded and evaluated. Student t test, Mann–Whitney U test, χ2 test, and Fisher exact test were performed to analyze the data. Results A total of 108 patients with COPD were included. Early rehabilitation program (ES and TS) plus exercise breathing for patients with COPD in the ICU showed decreased 30-day mortality, decreased hospital readmission, and improved HRQOL as compared with patients with COPD who received usual care. Conclusion Patients with COPD who were treated with an early rehabilitation program (ES and TS) combined with exercise breathing had a better prognosis and a higher QOL. Clinical trial.gov The study was registered under NCT03253380. [ABSTRACT FROM AUTHOR]

Background: Cu-IUCD is the most common method for long-acting reversible contraception, but its high potential use is hampered by menstrual complications especially heavy menstrual bleeding. So our work aimed to study the effect of Cu-IUCD on uterine artery blood flow through the assessment of uterine artery indices using transvaginal Doppler ultrasound (TVDU); and whether those potential findings could predict the risk of bleeding before insertion. Methods: This prospective observational study had performed on 100 women in the Department of Obstetrics and Gynecology, Zagazig University Hospitals who requested insertion of a Cu- IUD for contraception and who met the inclusion criteria. Pulsatility (PI) and resistance index (RI) of the uterine artery were measured just before, three, and six months post-insertion. Results: Forty-eight women came complaining of heavy menstrual bleeding and another 52 women were regularly menstruating. There was a substantial statistical variation concerning PI, and RI among women with IUD-induced heavy menstrual bleeding (n = 48) and those with the normal menstrual cycle (n = 52), while there was no difference as regards age, and abortion (P < 0.05). Uterine artery RI = 0.809 and PI = 2.078 was correlated with significant menstrual bleeding following insertion of IUCD. Conclusions:Our results endorse our assumption that vascular changes may represent a critical part in the occurrence of heavy menstrual bleeding, so a study of TVDU of the uterine artery indices is a valuable adjuvant indicative means to predict the abnormal uterine bleeding for women pursuing the use of Cu-IUCD and lead to the proper choice for contraception and decrease the complications as possible. [ABSTRACT FROM AUTHOR]

Background: Ultrasound is defined as a sound that cannot be heard by the human ear and has a frequency above 20kHz. The transducers on ultrasound machines have different frequencies and are in the range of 2-10MHz. Sonographic assessment of fetal growth for the estimation of fetal weight (EFW) is a common practice in obstetrics, providing valuable information for planning the mode of delivery and management of labor. Many formulae were proposed in the early 1980s using different combinations of standardized fetal biometric parameters, such as biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL). [ABSTRACT FROM AUTHOR]

Copyright of Egyptian Journal of Experimental Biology (Zoology) is the property of Egyptian Society of Experimental Biology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)