OBJECTIVE To evaluate the potential efficacy of low-intensity ultrasound （US） in combination with anticancer drugs to reverse multidrug resistance （MDR）in nude mice. METHODS A total of 40 male and female athymic n...OBJECTIVE To evaluate the potential efficacy of low-intensity ultrasound （US） in combination with anticancer drugs to reverse multidrug resistance （MDR）in nude mice. METHODS A total of 40 male and female athymic nude mice were inoculated subcutaneously with 5×10^6 HepG2/ADM and HepG2 cells. Ultrasound with pulsed irradiation at an average intensity of 0.5 W/cm^2 was given to the tumor area 10 rain after administration of adriamycin （ADM）. The tumor 3 dimensional diameters were measured by calipers before and after treatment, and the tumor growth indexes （TGI） calculated. RT-PCR was used to detect the gene levels of the HepG2/ADM cells. Immunohistochemical analyses for MDR proteins were conducted on the tumor tissues. RESULTS The ultrasonic treatment resulted in an average reduction in the tumor volume of 62% one month later. The relative mRNA levels of MDR1 and MRP were significantly different among the following 4 groups： untreated group as control, ADM treated; US treated; and ADM plus US treated. The mRNA levels of mdrl and mrp were down-regulated in the US groups compared to those of the non-ultrasound groups by multiple comparisons. The relative mRNA levels of Irp expression were not significantly changed. The results of immunohistochemistry indicated that tumor tissue from animals treated with US had remarkably low mdrl and mrp expression. CONCLUSION The results showed that low-intensity US can effectively reduce the size of adriamycin-resistant human hepotacarcinoma in a nude mouse model, and support the efficacy of US to overcome multiple mechanisms of drug resistance.展开更多
The search for Majorana fermions in topological superconductors is one of paramount research targets in physics today. Using a cryogenic scanning tunneling microscopy, we here report the signature of topologically non...The search for Majorana fermions in topological superconductors is one of paramount research targets in physics today. Using a cryogenic scanning tunneling microscopy, we here report the signature of topologically nontrivial superconductivity on a single material of β-Bi_2Pd films grown by molecular beam epitaxy. The superconducting gap associated with spinless odd-parity pairing opens on the surface and appears much larger than the bulk one due to the Dirac-fermion enhanced parity mixing of surface pair potential. Zero bias conductance peaks, probably from Majorana zero modes supported by such superconducting states, are identified at magnetic vortices. The superconductivity exhibits resistance to nonmagnetic defects, characteristic of time-reversal-invariant topological superconductors. Our study reveals β-Bi_2Pd as a prime platform to generate, manipulate and braid Majorana zero modes for quantum computation.展开更多
基金This work was supported by a grant from theNational Natural Science Foundation of China(No.30200060).
文摘OBJECTIVE To evaluate the potential efficacy of low-intensity ultrasound （US） in combination with anticancer drugs to reverse multidrug resistance （MDR）in nude mice. METHODS A total of 40 male and female athymic nude mice were inoculated subcutaneously with 5×10^6 HepG2/ADM and HepG2 cells. Ultrasound with pulsed irradiation at an average intensity of 0.5 W/cm^2 was given to the tumor area 10 rain after administration of adriamycin （ADM）. The tumor 3 dimensional diameters were measured by calipers before and after treatment, and the tumor growth indexes （TGI） calculated. RT-PCR was used to detect the gene levels of the HepG2/ADM cells. Immunohistochemical analyses for MDR proteins were conducted on the tumor tissues. RESULTS The ultrasonic treatment resulted in an average reduction in the tumor volume of 62% one month later. The relative mRNA levels of MDR1 and MRP were significantly different among the following 4 groups： untreated group as control, ADM treated; US treated; and ADM plus US treated. The mRNA levels of mdrl and mrp were down-regulated in the US groups compared to those of the non-ultrasound groups by multiple comparisons. The relative mRNA levels of Irp expression were not significantly changed. The results of immunohistochemistry indicated that tumor tissue from animals treated with US had remarkably low mdrl and mrp expression. CONCLUSION The results showed that low-intensity US can effectively reduce the size of adriamycin-resistant human hepotacarcinoma in a nude mouse model, and support the efficacy of US to overcome multiple mechanisms of drug resistance.
基金financially supported by the National Natural Science Foundation of ChinaMinistry of Science and Technology+2 种基金Ministry of Education of Chinasupports from the National Thousand-Young-Talents Programthe Tsinghua University Initiative Scientific Research Program
文摘The search for Majorana fermions in topological superconductors is one of paramount research targets in physics today. Using a cryogenic scanning tunneling microscopy, we here report the signature of topologically nontrivial superconductivity on a single material of β-Bi_2Pd films grown by molecular beam epitaxy. The superconducting gap associated with spinless odd-parity pairing opens on the surface and appears much larger than the bulk one due to the Dirac-fermion enhanced parity mixing of surface pair potential. Zero bias conductance peaks, probably from Majorana zero modes supported by such superconducting states, are identified at magnetic vortices. The superconductivity exhibits resistance to nonmagnetic defects, characteristic of time-reversal-invariant topological superconductors. Our study reveals β-Bi_2Pd as a prime platform to generate, manipulate and braid Majorana zero modes for quantum computation.
