Abstract: A method for preparing mesenchymal stem cell-derived exosomes on the basis of drug pretreatment, the method for preparing mesenchymal stem cell-derived exosomes comprising: using a statin to pretreat mesenchymal stem cells, and culturing the treated mesenchymal stem cells to collect exosomes secreted thereby. Also provided is an application of a statin in preparing a preparation for promoting the anti-apoptotic abilities and/or homing abilities of mesenchymal stem cells; and further provided is an application of a statin in preparing a preparation for promoting mesenchymal stem cells to secrete exosomes having myocardial infarction microenvironment-improving effects and/or myocardial repair abilities.

Abstract: A structured light system for object ranging/measurement is disclosed that implements a trapezoidal-based phase-shifting function with intensity ratio modeling using sinusoidal intensity-varied fringe patterns to accommodate for defocus error.

Abstract: A three dimensional surface contouring and ranging system (10) based on a digital fringe projection (18) and phase shifting technique is disclosed. In the system, three phase-shifted fringe patterns and an absolute phase mark pattern are used to determine the absolute phase map of the object (12). The phase map is then converted to the absolute x, y, and z coordinates of the object surface by a transformation algorithm. A calibration procedure is used to determine accurate values of system parameters required by the transformation algorithm. The parameters are initially indirectly measured through experiments to determine their approximate values. A calibration plate is then measured by the system at various positions. An iteration algorithm is then used to estimate the system parameters.

Abstract: A high resolution, compact size and low cost multi-degree-of-freedom geometric error measurement system for simultaneously measuring four geometric errors, horizontal straightness, vertical straightness, pitch and yaw. The pitch and yaw error measurements are based on a new method of angle measurement in turn based on the internal reflection effect at an air/glass boundary. The method uses a differential detection scheme to largely reduce the inherent non-linearity of the reflectance versus the angle of incidence in internal reflection. With non-linearity reduced, the displacement of the angle of incidence can be determined accurately by measuring the reflectance. The resolution and measurement range are determined by the initial angle of incidence, the polarization state of light, and the number of reflections. Compared with interferometers and autocollimators, this method has the advantage of a simple sensor design for applications ranging from very wide measurement range to extremely high resolution.

Abstract: A new method of angle measurement is based on the internal reflection effect at an air/glass boundary. The method uses a differential detection scheme to largely reduce the inherent non-linearity of the reflectance versus the angle of incidence in internal reflection. With non-linearity reduced, the displacement of the angle of incidence can be determined accurately by measuring the reflectance. The resolution and measurement range are determined by the initial angle of incidence, the polarization state of light, and the number of reflections. Compared with interferometers and autocollimators, this method has the advantage of a simple sensor design for applications ranging from very wide measurement range to extremely high resolution. Apparatus for accomplishing the method comprises a beamsplitter, a pair of critical angle prisms and a pair of photodiodes.