Dynamical analysis of a damped harmonic forced duffing oscillator with time delay.

This paper is concerned with a time-delayed controller of a damped nonlinear excited Duffing oscillator (DO). Since time-delayed techniques have recently been the focus of numerous studies, the topic of this investigation is quite contemporary. Therefore, time delays of position and velocity are utilized to reduce the nonlinear oscillation of the model under consideration. A much supplementary precise approximate solution is achieved using an advanced Homotopy perturbation method (HPM). The temporal variation of this solution is graphed for different amounts of the employed factors. The organization of the model is verified through a comparison between the plots of the estimated solution and the numerical one which is obtained utilizing the fourth order Runge-Kutta technique (RK4). The outcomes show that the improved HPM is appropriate for a variety of damped nonlinear oscillators since it minimizes the error of the solution while increasing the validation variety. Furthermore, it presents a potential model that deals with a diversity of nonlinear problems. The multiple scales homotopy technique is used to achieve an estimated formula for the suggested time-delayed structure. The controlling nonlinear algebraic equation for the amplitude oscillation at the steady state is gained. The effectiveness of the proposed controller, the time delays impact, controller gains, and feedback gains have been investigated. The realized outcomes show that the controller performance is influenced by the total of the product of the control and feedback gains, in addition to the time delays in the control loop. The analytical and numerical calculations reveal that for certain amounts of the control and feedback signal improvement, the suggested controller could completely reduce the system vibrations. The obtained outcomes are considered novel, in which the used methods are applied on the DO with time-delay. The increase of the time delay parameter leads to a stable case for the DO, which is in harmony with the influence of this parameter. This drawn curves show that the system reaches a stable fixed point which assert the presented discussion.

Studying the influence of external moment and force on a disc's motion.

In this work, the influence of a gyrostatic moment vector (GMV) and the Newtonian field (NF) on the rotatory motion of a restricted rigid body (RB) according to disc case around a fixed point is examined. The basic equation of the body motion is used to get the regulating motion's system as well as the three available independent first integrals. The system's six equations and these integrals were reduced to two equations of a quasi-linear two-degrees-of-freedom autonomous system and one first integral. The disc has been presumed to be quickly rotating around one of the ellipsoid of inertia's main axis. Poincaré's method of small parameter (PMSP) is applied to acquire the periodic solutions of the controlling system of the body's motion. Euler's angles are utilized to characterize the body's configuration at any instant in which it is graphed, as well as the obtained solutions to explore the good action of the body's parameters on its motion. The phase plane graphs of these solutions are presented to examine their stabilities. The relevance of this work may be traced to its wide range of applications in fields as diverse as physics, engineering, and life sciences, including assembly and machine design.

Evidence that the kinase-truncated c-Src regulates NF-κB signaling by targeting NEMO.

The tyrosine kinase c-Src and transcription factor NF-κB are considered crucial components required for normal osteoclastogenesis. Genetic ablation of either pathway leads to detrimental osteopetrotic phenotypes in mice. Similarly, obstruction of either pathway halts osteoclastogenesis and lessens various forms of bone loss. It has been shown previously that mice expressing a kinase domain-truncated c-Src, termed Src251, develop severe osteopetrosis owing to increased osteoclast apoptosis. It was further suggested that this phenomenon is associated with reduced Akt kinase activity. However, the precise mechanism underlying the osteoclast inhibitory effect of Src251 remains obscure. C-Src associates with TRAF6-p62 interacting with receptor activator of NF-κB (RANK) distal region and the complex facilitate activation of RANK down stream signal transduction cascades including NF-κB. Given this proximity between c-Src and NF-κB signaling in osteoclasts, we surmised that inhibition of osteoclastogenesis by Src251 may be achieved through inhibition of NF-κB signaling. We have demonstrated recently that NEMO, the regulatory subunit of the IKK complex, is crucial for osteoclastogenesis and interacts with c-Src in osteoclast progenitors. Transfection studies, in which we employed various forms of c-Src and NEMO, revealed that the dominant negative form of c-Src, namely Src251, mediates degradation of NEMO thus halting NF-κB signaling. Furthermore, degradation of NEMO requires its intact zinc finger domain which is located at the ubiquitination domain. This process also requires appropriate cellular localization of Src251, since deletion of its myristoylation domain ablates its degradation capacity. Buttressing these findings, the expression of NEMO and NF-κB signaling were significantly reduced in monocytes collected from Src251 transgenic mice.

Extracts and fractions of Thymus capitatus exhibit antimicrobial activities.

Preliminary phytochemical screening of the plant Thymus capitatus exhibited the presence of saponins, resins, flavonoids, essential and fixed oils. Aqueous and ethanolic extracts (10-200 mg/ml) as well as saponin, resin and essential oil of the plant (10-5000 micrograms/ml inhibited the growth of several bacteria and fungi.

Salivary female sex hormone levels and gingivitis in pregnancy.

Salivary estradiol 17 beta (E2-17 beta) and progesterone (P) were determined by using radioimmunoassay techniques in 30 pregnant females in the first, second and third trimesters as well as in 10 non-pregnant controls during the luteal phase of the menstrual cycle. Plaque index (P.I.), gingival index (G.I.) and retention index (R.I.) were measured in all cases. The data obtained showed that the levels of the two hormones in saliva were significantly increasing during the 3 trimesters of pregnancy. P.I. and R.I. did not change, however, G.I. was significantly higher in the second and third trimesters when compared with controls. A correlation between both E2--17 beta and P during pregnancy and gingival changes is suggested.