Time-periodic Poiseuille-type solution with minimally regular flow rate

The nonstationary Navier–Stokes equations are studied in the infinite cylinder Π = {x = (x', xn) ∈ Rn: x' ∈ σ ∈ R n – 1: – ∞ < xn < ∞, n = 2, 3} under the additional condition of the prescribed time-periodic flow-rate (flux) F(t). It is assumed that the flow-rate F belongs to the space L2(0, 2π), only. The time-periodic Poiseuille solution has the form u(x, t) = (0, ... , 0, U(x', t)), p(x,t) = –q(t)xn + p0(t), where (U(x', t), q(t)) is a solution of an inverse problem for the time-periodic heat equation with a specific over-determination condition. The existence and uniqueness of a solution to this problem is proved.

Periodic Heat Stress Licenses EMSCs Differentiation Into Osteoblasts via YAP Signaling Pathway Activation

BackgroundThe repair and regeneration of large bone defects represent a highly challenging task for bone tissue engineering. Although recent studies have shown that osteogenesis is stimulated by periodic heat stress, the thermal regulation of the osteogenic differentiation of ectomesenchymal stem cells (EMSCs) is not well studied. Methods and resultsIn this study, the direct effects of periodic heat stress on the differentiation of EMSCs into osteoblasts were investigated. EMSCs derived from rat nasal respiratory mucosa were seeded in culture plates, followed by 1 h of heat stress at 41 °C every 7 days during osteogenic differentiation. Based on the results of the present study, periodic heating increases alkaline phosphatase (ALP) activity, upregulates osteogenic-related proteins and promotes EMSC mineralization. In particular, increased YAP nuclear translocation and YAP knockdown inhibited osteogenic differentiation induced by heat stress. Furthermore, the expression and activity of transglutaminase 2 (TG2) were significantly increased after YAP nuclear translocation. ConclusionTogether, these results indicate that YAP plays a key role in regulating cellular proteostasis under stressful cellular conditions by modulating the TG2 response.

Computational analysis of an infinite magneto-thermoelastic solid periodically dispersed with varying heat flow based on non-local Moore–Gibson–Thompson approach

In this investigation, a computational analysis is conducted to study a magneto-thermoelastic problem for an isotropic perfectly conducting half-space medium. The medium is subjected to a periodic heat flow in the presence of a continuous longitude magnetic field. Based on Moore–Gibson–Thompson equation, a new generalized model has been investigated to address the considered problem. The introduced model can be formulated by combining the Green–Naghdi Type III and Lord–Shulman models. Eringen’s non-local theory has also been applied to demonstrate the effect of thermoelastic materials which depends on small scale. Some special cases as well as previous thermoelasticity models are deduced from the presented approach. In the domain of the Laplace transform, the system of equations is expressed and the problem is solved using state space method. The converted physical expressions are numerically reversed by Zakian’s computational algorithm. The analysis indicates the significant influence on field variables of non-local modulus and magnetic field with larger values. Moreover, with the established literature, the numerical results are satisfactorily examined.