Computations are performed to determine the steady 3-D viscous fluid flow forces acting on the stationary spherical suspended particle at low and moderate Reynolds numbers in the range of 0.1≤Re≤200. ...A slip is supposed on the boundary so that the slip velocity becomes proportional to the shear stress. This model possesses a single parameter to account for the slip coefficient λ (Pa.s/m), which is made dimensionless and is called Trostel number (Tr=λ a/μ). Decreasing slip, increases drag in all Reynolds limits, but slip has smaller effects on drag coefficient at lower Reynolds number regimes. Increasing slip at known Reynolds number causes to delay of flow separation and inflect point creation in velocity profiles. At full slip conditions, shear drag coefficient will be zero and radial drag coefficient reaches to its maximum values. Flow around of sphere at full-slip condition is not equal to potential flow around a sphere. Present numerical results corresponding to full slip (Tr→0) are in complete accord with certain results of flow around of inviscid bubbles, and the results corresponding to no-slip (Tr→∞) have excellent agreement with the results predicted by the no-slip boundary condition.
In this investigation, semiempirical and numerical studies of blood flow in a viscoelastic artery were performed using the Cosserat continuum model. The large-amplitude oscillatory shear deformation ...model was used to quantify the nonlinear viscoelastic response of blood flow. The finite difference method was used to solve the governing equations, and the particle swarm optimization algorithm was utilized to identify the non-Newtonian coefficients (
k
υ
and
γ
υ
). The numerical results agreed well with previous experimental results.
Abstract
The objective of this article is to derive an analytical solution for a two-dimensional temperature field in a hollow cylinder, which is subjected to a periodic boundary condition at the ...outer surface, while the inner surface is insulated. The material is assumed to be homogeneous and isotropic with time-independent thermal properties. Because of the time-dependent term in the boundary condition, Duhamel's theorem is used to solve the problem for a periodic boundary condition. The periodic boundary condition is decomposed using the Fourier series. This condition is simulated with harmonic oscillation; however, there are some differences with the real situation. To solve this problem, first of all the boundary condition is assumed to be steady. By applying the method of separation of variables, the temperature distribution in a hollow cylinder can be obtained. Then, the boundary condition is assumed to be transient. In both these cases, the solutions are separately calculated. By using Duhamel's theorem, the temperature distribution field in a hollow cylinder is obtained. The final result is plotted with respect to the Biot and Fourier numbers. There is good agreement between the results of the proposed method and those reported by others for this geometry under a simple harmonic boundary condition.
The drag and lift forces acting on a rotating impenetrable spherical suspended particle in a uniform flow are numerically studied by means of three-dimensional numerical simulation with slip boundary ...condition at Reynolds numbers in the range of 0.1<Re<100. The tangential shear stress is assumed to be proportional to slip velocity at the boundary. A single dimensionless parameter, the so-called Trostel number (Tr), is defined to account for the slip at the boundary of the sphere. Increasing rotation and slip changes the flow patterns around the spherical particle. Increasing slip decreases the effects of rotation on the flow patterns around the rotating sphere. Rotation increases the drag and lift force exerted by flow at the surface of sphere but the values of drag and lift coefficients decrease by increasing slip. At full slip condition, rotation of the sphere has no significant effects on the drag coefficient values; moreover the lift coefficient of flow around the rotating spherical particle will vanish. Present numerical results at Tr=10e5 are in good agreement with other numerical results of flow around the rotating sphere at no-slip condition.
The correlation between insulin resistance and homocysteine levels in patients with preeclampsia indicate that insulin resistance in preeclampsia is related to endothelial dysfunction.
Informal caregivers are the primary source of support for adults with chronic conditions and disabilities. Empirical research highlights chronic stress and other risks of adverse outcomes of ...caregiving. Acceptance and Commitment Therapy (ACT) is an emerging evidenced-based practice that shows promise in improving an array of outcomes, theoretically by increasing psychological flexibility as the primary process of change. Research has begun to evaluate ACT among informal caregivers of adult populations, and a systematic review is now needed to summarise this evidence base.
Electronic searches from five databases, including PubMed, PsycInfo, Embase, CINAHL, and Cochrane Library, yielded an initial 7896 hits, which after screening for inclusion criteria, resulted in 21 clinical trials. Studies were coded to synthesise the feasibility, effectiveness, and quality of evidence. Findings show that ACT was reported to be largely feasible and acceptable. However, the efficacy of ACT was mixed, with a more consistent pattern for informal caregivers of people with dementia.
Several methodological quality issues limited the findings. However, theoretical synthesis and preliminary evidence support the promising effect of ACT in subgroups of informal caregivers. Research on the process of change, as well as larger-scale, methodologically rigorous trials, are needed to consolidate these findings.
•ACT has been empirically evaluated for informal caregivers of adults with chronic conditions.•Limitations in the quality of studies were observed, but initial evidence is promising.•The implication of ACT in the context of caregiving is discussed.•More research is needed to consolidate findings in subgroups of caregivers.•Future research should focus on ACT process functioning and effectiveness in caregivers.
In this paper to study the thermoelastic behavior of a gas turbine blade, a computer code based on Conjugate Heat Transfer method was developed to solve the coupled external flow field and the ...internal temperature field inside a gas turbine blade. An interpolation method based on the 3D shape functions was used to calculate the correct temperature values at the boundaries to determine the stress field. For the materials with temperature dependent mechanical and physical properties, the thermal stresses exhibit a nonlinear behavior. In these cases, an analytic solution for the energy and equilibrium equations to obtain the temperature distribution and the stress field, knowing K(T), α(T), E(T) would be impossible and the numerical schemes should be employed instead. The results show that the stress for the materials with temperature dependent properties is higher than that for the cases where the blade material properties are constant with temperature. Further, the temperature field and the flow field obtained by the present method were compared to the available experimental findings. The results show a good agreement.
PD-L1 is the main ligand for the immune inhibitory receptor PD-1. This ligand is frequently expressed by melanoma cells. In this study, we investigated whether PD-L1 expression is controlled by ...melanoma driver mutations and modified by oncogenic signaling inhibition.
Expression of PD-L1 was investigated in a panel of 51 melanoma cell lines containing different oncogenic mutations, including cell lines with innate and acquired resistance to BRAF inhibitors (BRAFi). The effects of targeted therapy drugs on expression of PD-L1 by melanoma cells were investigated.
No association was found between the level of PD-L1 expression and mutations in BRAF, NRAS, PTEN, or amplification of AKT. Resistance to vemurafenib due to the activation of alternative signaling pathways was accompanied with the induction of PD-L1 expression, whereas the resistance due to the reactivation of the MAPK pathway had no effect on PD-L1 expression. In melanoma cell lines, the effects of BRAF, MEK, and PI3K inhibitors on expression of PD-L1 were variable from reduction to induction, particularly in the presence of INFγ. In PD-L1-exposed lymphocytes, vemurafenib paradoxically restored activity of the MAPK pathway and increased the secretion of cytokines.
In melanoma cell lines, including BRAFi-resistant cells, PD-L1 expression is variably regulated by oncogenic signaling pathways. PD-L1-exposed lymphocytes decrease MAPK signaling, which is corrected by exposure to vemurafenib, providing potential benefits of combining this drug with immunotherapies.
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