干扰素的功能表达机理——2′-5′三腺苷酸对巨噬细胞的激活对甲胎蛋白的对抗作用

本试验结果表明:1.2′-5′三腺苷酸(2′-5′P_3A_3)有激活多种来源(包括人)巨噬细胞的吞噬作用,说明2′-5′P_3A_3对巨噬细胞的激活作用具有普遍意义。2.甲胎蛋白(AFP)能抑制巨噬细胞的吞噬功能,可能对肝癌的发生有一定的作用。本工作证实2′-5′P_3A_3能抵消AFP对巨噬细胞的抑制作用。3.关于2′-5′P_3A_3生物功能的研究,过去都要用CaCl_2等方法将它引入细胞,这对临床应用是不实际的。本文不使用CaC国_2等方法,2′-5′P_3A_3即能激活巨噬细胞。     

MECHANISM OF INTERFERON ACTION——ACTIVATION OF MACROPHAGES AND ANTAGONISM TO a-FETO-PROTEIN BY _(ppp)A_(2'p5')A_(2'p5')A

_(ppp)A_(2'p),'A_(2'p,)'A(2'-5'P_3A_3) activates macrophages and increases the phagocytosis of macrophages from different species including human beings. This indicates that the activation of macrophages may be a general action of 2'-5'P_3A_3. This discovery broadens the effect of 2'-5'P_3A_3 beyond the antiviral field.α-Feto-protein (AFP) inhibits the phagocytosis of macrophages and may be involved in the development of hepatoma. Data presented here show that 2'-5'P_3A_3 can antagonize this suppressive effect of AFP.Methods used so far for introducing 2'-5'P_3A_3 into the cells were made with the aid of CaCl_2, etc. under conditions which may not be the same as those used clinically. It was found that 2'-5'P_3A_3 can develop its biological effect without the aid of CaCl_2, etc.     

大水滴撞击翼型后的破碎过程研究

针对大水滴撞击翼型壁面问题,通过引入表面张力系数和壁面接触角,建立了二维计算模型;采用水平集法从微观角度研究了水滴撞击翼型的过程.数值模拟结果表明:低速环境下气动力和表面张力是影响水滴变形的主要因素.大水滴主要撞击在翼型前缘点及吸力面,S801、S802、S803、S804四种翼型中S803翼型抗结冰能力最好,S804...     

Effect of SiN:H_x passivation layer on the reverse gate leakage current in GaN HEMTs

This paper concentrates on the impact of SiN passivation layer deposited by plasma-enhanced chemical vapor deposition(PECVD) on the Schottky characteristics in GaN high electron mobility transistors(HEMTs). Three types of SiN layers with different deposition conditions were deposited on GaN HEMTs. Atomic force microscope(AFM), capacitance-voltage(C-V), and Fourier transform infrared(FTIR) measurement were used to analyze the surface morphology, the electrical characterization, and the chemical bonding of SiN thin films, respectively. The better surface morphology was achieved from the device with lower gate leakage current. The fixed positive charge Q_f was extracted from C-V curves of Al/SiN/Si structures and quite different density of trap states(in the order of magnitude of 1011-1012 cm~(-2)) was observed.It was found that the least trap states were in accordance with the lowest gate leakage current. Furthermore, the chemical bonds and the %H in Si-H and N-H were figured from FTIR measurement, demonstrating an increase in the density of Q_f with the increasing %H in N-H. It reveals that the effect of SiN passivation can be improved in GaN-based HEMTs by modulating %H in Si-H and N-H, thus achieving a better Schottky characteristics.     

硅硼掺杂碳点的制备及其在血红蛋白传感中的应用

杂原子掺杂是提高碳点荧光性能的有效手段.本研究以柠檬酸(C6 H8 O7)、硼酸(H3 BO3)、3-氨丙基三乙氧基硅烷(APTES)为原料,采用微波法一步制备硅和硼掺杂的碳点(SiBCDs);在SiBCDs前驱体中加入聚丙烯酸钠(PAAS),微波法制备了水溶性好、量子产率高的PAAS-SiBCDs.采用X射线衍射(XRD)、X射线光电子能谱(XPS)及红外光谱(FT-IR)对制备的碳点进行了表征.SiBCDs粒径约4~8 nm,PAAS-SiBCDs平均粒径5.2 nm,两者最大激发波长和发射波长分别为350和445 nm,荧光量子产率(QY)分别为20.1%和34.6%.基于血红蛋白对PAAS-SiBCDs的荧光猝灭效应,建立了全血样品中血红蛋白(Hb)的检测方法,线性范围为0.21~5.22μmol/L,检出限为0.06μmol/L(S/N=3).