PDTC antagonized polysaccharide-induced apoptosis in MCF-7 cells through a caspase-8 mediated Fas pathway

Cartilage polysaccharide (PS) was extracted from porcine cartilage to investigate its anti-tumor effect. In this study, we showed that PS induced apoptosis in MCF-7 breast cancer cells by activating the caspase-8 mediated Fas signaling pathway. The PS inhibited MCF-7 cell proliferation in a dose-dependent and time-dependent manner, and had no toxic effect on normal cells such as NIH-3T3 cells. An increase of Fas protein expression was first located on the nuclear membrane and then on the outside membrane. Cleaved caspase-8 was activated after PS treatment. NF-κB activation was not involved in the PS induced apoptosis, but the NF-κB inhibitor PDTC may act as a PS antagonist to reduce the apoptosis rate and Fas protein expression in PS-induced apoptosis in MCF-7 cells.     

Use of water vapor for suppressing the growth of unstable low-κ interlayer in HfTiO gate-dielectric Ge metal-oxide-semiconductor capacitors with sub-nanometer capacitance equivalent thickness

Annealing of high-permittivity HfTiO gate dielectric on Ge substrate in different gases (N₂, NH₃, NO and N₂O) with or without water vapor is investigated. Analysis by transmission electron microscopy indicates that the four wet anneals can greatly suppress the growth of a GeO_x interlayer at the dielectric/Ge interface, and thus decrease interface states, oxide charges and gate leakage current. Moreover, compared with the wet N₂ anneal, the wet NH₃, NO and N₂O anneals decrease the equivalent permittivity of the gate dielectric due to the growth of a GeO_xN_y interlayer. Among the eight anneals, the wet N₂ anneal produces the best dielectric performance with an equivalent relative permittivity of 35, capacitance equivalent thickness of 0.81 nm, interface-state density of 6.4 × 10¹¹ eV^− 1 cm^− 2 and gate leakage current of 2.7 × 10^− 4 A/cm² at V_g = 1 V.     

槲寄生通过抑制NF-κB活性来诱导人大肠癌HCT116细胞凋亡

目的:探讨槲寄生诱导人大肠癌HCT116细胞凋亡所涉及的信号转导途径。方法:采用MTT法测定细胞的增殖活力,琼脂糖凝胶电泳观察细胞调亡,流式细胞仪进行细胞周期分析,Westernblotting和DIG-EMSA研究细胞调亡途径。结果:槲寄生对HCT116细胞有明显的生长抑制作用,琼脂糖凝胶电泳检测到典型的DNA梯状条带;槲寄生可通过抑制IκBα蛋白磷酸化进而抑制NF-κB;槲寄生可增强羟基喜树碱对HCT116细胞诱导的凋亡作用。结论:槲寄生对HCT116细胞有明显的生长抑制和诱导调亡作用,并且通过抑制NF-κB活性来诱导人大肠癌HCT116细胞凋亡。     

黄芩苷对动脉粥样硬化家兔的保护作用及其机制

目的:探讨黄芩苷对动脉粥样硬化(AS) 家兔的保护作用及可能机制。方法:新西兰白兔30只, 随机分为正常组、模型组、黄芩苷治疗组(300 mg/kg) 、黄芩苷预防组(100 mg/kg) 、阳性药(辛伐他汀) 对照组, 每组6 只。酶法测定各组血清及肝脏中TC 、TG 、低密度脂蛋白(LDL) 、高密度脂蛋白含量, 主动脉苏丹Ⅳ染色测AS 斑块面积/总面积, HE 染色观察主动脉及肝脏形态学改变。ELASA 方法测血清中肿瘤坏死因子(TNF-α) 、白细胞介素-1β(IL-1β) 、脂联素(Adiponectin) 的水平。免疫组化法检测主动脉弓处的NF-κB 的表达。结果:黄芩苷治疗组、黄芩苷预防组、阳性药对照组主动脉粥样硬化斑块面积小于模型组(P <0.01), 黄芩苷治疗组、黄芩苷预防组、阳性药对照组血清及肝脏中TC 、LDL 水平较模型组明显降低(P <0.01), 黄芩苷治疗组、黄芩苷预防组血清中TNF-α、IL-1β 和脂联素水平较模型组明显降低(P<0.01, P <0.05), 黄芩苷治疗组、黄芩苷预防组主动脉壁上NF-κB 的表达低于模型组(P <0.01) 。结论:黄芩苷通过升高脂联素、下调NF-κB 抑制炎症反应及调节血脂两个方面对AS 起保护作用, 这可能是其抑制AS 的形成及发展的重要机制之一。     

核转录因子κB 活化途径干预对肝细胞癌变的影响

肝癌发生是一多中心、多病因、多阶段的发展过程。本文对NF-κB 活化途径干预与肝细胞癌变关系的研究进展进行简单的综述。NF-κB 的过度表达参与了肝癌的发生、发展。NF-κB 表达的进行性增加, 可反映肝细胞的早期癌变。而抑制NF-κB 的活性可干预肝细胞恶性转化过程, 可能成为肝癌治疗的新方向。     

认知双向中继网络在κ-μ衰落信道下的中断性能分析

针对认知双向中继网络在进行数据传输时面临的复杂无线信道场景问题,采用广义κ-μ分布构建认知双向中继网络中的视距和非视距无线传输信道,推导次网络在κ-μ衰落信道下的统一中断概率,并分析次网络在多种单一和混合衰落信道情况下的中断性能.仿真结果表明,无线信道的衰落程度对次网络的中断概率影响显著,依据衰落信道类型合理设置网络参...     

Rheological characterisation of yolk-based gels and Staphylococcus growth

Model yolk-based (10% v/v) gels with different concentrations of κ-carrageenan (0–2% w/w) were characterised employing rheological measurements, textural analysis and scanning electron microscopy. Additionally, the effect of the microstructure of the model gels on the growth rate of Staphylococcus was also evaluated. In all cases, the nature of the gel was dominated by the elastic component, specifically, 1.5, 1.75 and 2% κ-carrageenan samples can be described as ‘true gels’ (tan δ < 0.1). Maximum strength of the interactions between rheological units (A) was observed with 1.75% κ-carrageenan (4.74 ± 0.38 kPa), which indicates that the strength of interactions was determined not only by κ-carrageenan concentration, but also by the amount of yolk. Finally, an inverse linear correlation was found between the maximum specific growth rate of Staphylococcus and rheological data (R² > 0.99).     

Preparation of Chloride Salt of Octa (Aminopropylsilsesquioxane) Filled Low-κ Epoxy Composites with Improved Thermal Stability and Low Water Absorption

ABSTRACT

Herein, a kind of low-κ epoxy composites with excellent comprehensive properties were prepared by introducing chloride salt of octa (aminopropylsilsesquioxane). The dielectric constant (10⁶ Hz) of the composite was decreased by 0.94 when the fillers loading was only 3 wt%. The thermal stability and shore hardness were both improved, and the water adsorption was reduced. The improved properties of the composites were mainly attributed to the intrinsic cage-like structure of the filler and its good dispersion in the matrix. Moreover, the strong interface interaction between the filler and matrix also played an important role.