Satellite communications have attracted significant interests due to its advantages of large footprint and massive access.However,the commonly used onboard beamforming is hard to achieve reliable security because of t...Satellite communications have attracted significant interests due to its advantages of large footprint and massive access.However,the commonly used onboard beamforming is hard to achieve reliable security because of the highly correlated legitimate and wiretap downlink channels.We exploit the benefits of satellite-terrestrial integrated network(STIN)and a novel absorptive reconfigurable intelligent surface(RIS)for improving the security of satellite downlink communications(SDC)in the presence of eavesdroppers(Eves).This paper aims to maximize the achievable secrecy rate of the earth station(ES)while satisfying the signal reception constraints,harvested power threshold at the RIS,and total transmit power budget.To solve this nonconvex problem,we propose a penalty-function based dual decomposition scheme,which firstly transforms the original problem into a two-layer optimization problem.Then,the outer layer and inner problems are solved by utilizing the successive convex approximation,Lagrange-dual and Rayleigh quotient methods to obtain the beamforming weight vectors and the reflective coefficient matrix.Finally,simulation results verify the effectiveness of the proposed scheme for enhancing the SDC security.展开更多
三阴性乳腺癌(triple negative breast cancer,TNBC)恶性程度高,预后差,其p53基因的突变频率达80%以上。日蟾蜍它灵(gamabufotalin,CS-6)是日本蟾蜍的皮肤分泌物,有研究表明CS-6具有抗癌作用,但其对TNBC的作用和机制尚无报道。本文采用...三阴性乳腺癌(triple negative breast cancer,TNBC)恶性程度高,预后差,其p53基因的突变频率达80%以上。日蟾蜍它灵(gamabufotalin,CS-6)是日本蟾蜍的皮肤分泌物,有研究表明CS-6具有抗癌作用,但其对TNBC的作用和机制尚无报道。本文采用MTT法和细胞克隆形成实验检测了不同浓度CS-6对TNBC细胞系MDA-MB-468和MDA-MB-231细胞增殖的影响;采用Western-blot检测了CS-6在外源和内源水平对p53和热休克蛋白90(heat shock protein 90,HSP90)表达水平的影响;采用联合指数及等效线分析法考察了CS-6和HSP90的抑制剂坦螺旋霉素(tanespimycin,17-AAG)对MDA-MB-468和MDA-MB-231细胞增殖的协同作用。结果显示,CS-6明显抑制MDA-MB-468和MDA-MB-231细胞的增殖,其抑制增殖机制有可能与降解HSP90/突变p53有关;而且,CS-6和HSP90抑制剂17-AAG联合用药对抑制MDA-MB-468和MDA-MB-231细胞增殖具有协同作用。展开更多
基金supported by the National Natural Science Foundation of China(No.62201592)the Research Plan Project of NUDT(ZK21-33)the Young Elite Scientist Sponsorship Program of CAST,China(2021-JCJQ-QT-048)。
文摘Satellite communications have attracted significant interests due to its advantages of large footprint and massive access.However,the commonly used onboard beamforming is hard to achieve reliable security because of the highly correlated legitimate and wiretap downlink channels.We exploit the benefits of satellite-terrestrial integrated network(STIN)and a novel absorptive reconfigurable intelligent surface(RIS)for improving the security of satellite downlink communications(SDC)in the presence of eavesdroppers(Eves).This paper aims to maximize the achievable secrecy rate of the earth station(ES)while satisfying the signal reception constraints,harvested power threshold at the RIS,and total transmit power budget.To solve this nonconvex problem,we propose a penalty-function based dual decomposition scheme,which firstly transforms the original problem into a two-layer optimization problem.Then,the outer layer and inner problems are solved by utilizing the successive convex approximation,Lagrange-dual and Rayleigh quotient methods to obtain the beamforming weight vectors and the reflective coefficient matrix.Finally,simulation results verify the effectiveness of the proposed scheme for enhancing the SDC security.
文摘三阴性乳腺癌(triple negative breast cancer,TNBC)恶性程度高,预后差,其p53基因的突变频率达80%以上。日蟾蜍它灵(gamabufotalin,CS-6)是日本蟾蜍的皮肤分泌物,有研究表明CS-6具有抗癌作用,但其对TNBC的作用和机制尚无报道。本文采用MTT法和细胞克隆形成实验检测了不同浓度CS-6对TNBC细胞系MDA-MB-468和MDA-MB-231细胞增殖的影响;采用Western-blot检测了CS-6在外源和内源水平对p53和热休克蛋白90(heat shock protein 90,HSP90)表达水平的影响;采用联合指数及等效线分析法考察了CS-6和HSP90的抑制剂坦螺旋霉素(tanespimycin,17-AAG)对MDA-MB-468和MDA-MB-231细胞增殖的协同作用。结果显示,CS-6明显抑制MDA-MB-468和MDA-MB-231细胞的增殖,其抑制增殖机制有可能与降解HSP90/突变p53有关;而且,CS-6和HSP90抑制剂17-AAG联合用药对抑制MDA-MB-468和MDA-MB-231细胞增殖具有协同作用。
