Biomedical subjects

Xiaomeng Yang

Publications and source records attributed to Xiaomeng Yang.

4 recordsLinked to original sources

PubMed2005

Bending mode effect on sensitivity of plate surface acoustic wave pressure sensors.

The bending mode effect on sensitivity of pressure sensors operating with surface acoustic waves (SAW) propagating over the surface of a plate is analyzed using Tiersten's perturbation integral for frequency shifts in a piezoelectric resonator due to the presence of initial fields. For a plate subjected to nonpure bending, the SAW speed, whose shift in response to pressure determines the sensitivity, can be defined locally through the local variations of the effective material constants. Three common bending modes of pure bending, bending under a concentrate load, and bending under a uniformly load are analyzed and compared.

Journal Article↗

PubMed2005

Effect of protein kinase C on proliferation and apoptosis of T lymphocytes in idiopathic thrombocytopenic purpura children.

It is well-documented that T lymphocyte proliferation and apoptosis are abnormal in idiopathic thrombocytopenic purpura (ITP) children. However, the underlying regulation mechanisms especially in terms of signal transduction remain unknown. In this paper, we reported the changes of protein kinase C (PKC) activity in peripheral blood T lymphocytes and the effect of PKC on T lymphocyte proliferation and apoptosis. We demonstrated that in ITP children, the activator (PMA) and inhibitor (H-7) of PKC affected on T lymphocyte proliferation and apoptosis dramatically, but they altered little in healthy children. PKC activity was significantly enhanced in ITP children together with an increased expression of FasL on CD3+T, CD4+T and CD8+T cells, resulting in a positive correlation between PKC activity and the expression of FasL on T cells. While the PKC activity and the platelet count were negatively correlated. Taken together, our findings suggest that the PKC activation may enhance T lymphocytes activity, suppress T cell apoptosis and be involve in thrombocytes damage as a mechanism related to immune pathogenesis of ITP.

Adolescent↗

PubMed2005

Polarization and apoptosis of T cell subsets in idiopathic thrombocytopenic purpura.

It is well-known that idiopathic thrombocytopenic purpura (ITP) is an acquired organ-specific autoimmune hemorrhagic disease and dysfunctional cellular immunity is considered important in the pathophysiology of ITP. However, polarization patterns and apoptosis profiles of T lymphocytes remain unclear. In this study, we investigated the polarization of T cell subsets, the expressions of apoptotic proteins Fas/FasL on the subsets and the level of anti-apoptotic gene bcl-2 and bax mRNA. It was demonstrated that the ratios of Th1/Th2 and Tc1/Tc2 in ITP children were increased obviously and that the average percentages were increased clearly for Th1 and Th2, but not for Tc1 and Tc2. In ITP children, the enhancing expressions were detected for FasL on Th1 and Tc1 and for Fas on Th2 and Tc2. With increasing level of bcl-2 mRNA and decreasing expression of bax mRNA in ITP children, the ratio of bcl-2/bax mRNA was improved obviously, which was positive correlated with the ratio of Th1/Th2. Taken together, our findings indicate that ITP is a Th1 predominant disease. This polarization pattern of T cell subsets might be related to the high ratio of bcl-2/bax mRNA and the abnormal expressions of Fas and FasL on T cell subsets.

Apoptosis↗

PubMed2003

Two-dimensional equations for electroelastic plates with relatively large shear deformations.

A set of two-dimensional, nonlinear equations for electroelastic plates in moderately large thickness-shear deformations is obtained from the variational formulation of the three-dimensional equations of nonlinear electroelasticity by expanding the mechanical displacement vector and the electric potential into power series in the plate thickness coordinate. As an example, the equations are used to study nonlinear thickness-shear vibrations of a quartz plate driven by an electrical voltage. Nonlinear electrical current amplitude-frequency behavior near resonance is obtained. The equations and results are useful in the study and design of pieszoelectric crystal resonators and the measurement of nonlinear material constants of electroelastic materials.

Journal Article↗