Kindergarten children's representation and understanding of written number symbols

Two samples of kindergarten children's representation and understanding of written number symbols were examined in two time points in one academic year. About 85% of Chinese five year olds (mean = 5 years 10 months) were able to use conventional number symbols to represent the quantity of 30 or larger. At the end of the kindergarten year, 94% of Chinese six year olds (mean = 6 years 4 months) were able to use conventional number symbols to represent the quantity of 100 or larger. Some Chinese six year olds had problems in representing written addition and subtraction tasks. Children's ability to represent written number symbols, ability to represent written addition and subtraction formula and their performance on written addition and subtraction were closely related. The performance of children in a university-affiliated childcare center was better than that of the center serving working-class families in Time 1, but the performance reversed at the end of the kindergarten year.     

Computerized tomography based on DEI refraction information.

Conventional computerized tomography (CT) technique is based on the absorption contrast. In recent years, X-ray phase-contrast CT (PCCT) has been developing rapidly. It uses the phase information to reconstruct the object and provide high contrast and spatial resolution. Diffraction enhanced imaging (DEI) method is one of the three phase-sensitive X-ray imaging techniques. DEI method employs an analyzer crystal to extract the object's refraction information which can be used for CT. However, when DEI refraction CT is combined with the conventional CT algorithm, it should be satisfied that the refraction information of an arbitrary point in the object is invariable at every projection view. In this paper, the invariance condition of refraction information is analyzed and two feasible methods are provided for reconstruction. Using these two methods, two samples of weak absorption are reconstructed with the experimental data obtained at Beijing Synchrotron Radiation Facility (BSRF).     

Treatment of hemophilia A by living mother-to-son splenic transplantation. First case report in the world.

A case of severe hemophilia A was treated by living mother-to-son splenic transplantation. The recipient was a 9-year-old boy. After splenic transplantation, the level of blood factor VIII:C was increased, and no spontaneous hemorrhage occurred. The boy was followed up for over two years. This is a case of spleen allotransplantation with the longest function in the world.

     

红细胞沉降率IV──红细胞沉降速度测量的原理和方法

本文从理论上提出了红细胞沉降速度的准确概念，阐明了红细胞沉降过程所包含的物理和生理信息，提出了一种新型测量红细胞沉降速度及其它特征参数的方法，并给出了其主体、硬件和软件设计要点。