Multimode waveguide bend is one of the key components for realizing high-density mode-division multiplexing systems on chip.However,the reported multimode waveguide bends are either large,bandwidth-limited or fabricat...Multimode waveguide bend is one of the key components for realizing high-density mode-division multiplexing systems on chip.However,the reported multimode waveguide bends are either large,bandwidth-limited or fabrication-complicated,which hinders their applications in future high-density multimode photonic circuits.Here we propose a compact multimode waveguide bend supporting four TE modes simply by shape-optimizing with transformation optics.The shape of the waveguide is optimized in the virtual space with gradient distribution of the refractive index,so that the scattering loss and intermode cross talk are well suppressed.After conformal mapping back into the physical space,a compact(effective radius of 17μm)multimode bending waveguide is obtained.Simulations show that the proposed multimode waveguide bend has little loss(<0.1 dB)and low cross talk(<−20 dB)throughout an ultrabroad wavelength range of 1.16–1.66μm.We also fabricated the shape-optimized multimode bending waveguide on a silicon-on-insulator wafer.At 1550 nm wavelength,the measured excess losses for the four lowest-order TE modes are less than 0.6 dB,and the intermode cross talks are all below−17 dB.Our study paves the way for realizing high-density and large-scale multimode integrated optical circuits for optical interconnect.展开更多
Background:HIV-1 Vpu acts by counteracting the tethering function of tetherin and resulting in the release of HIV-1 virion.Disrupting Vpu-tetherin interactions may provide a promising new target for antiretroviral the...Background:HIV-1 Vpu acts by counteracting the tethering function of tetherin and resulting in the release of HIV-1 virion.Disrupting Vpu-tetherin interactions may provide a promising new target for antiretroviral therapy.Methods:Polypeptides that covered the amino acid sequence on the interface of Vpu-tetherin complex were designed.Phenotypic susceptibilities and cellular toxicities to the polypeptides were measured.The mechanisms of the anti-HIV-1 polypeptides were determined by the Western blot analysis and laser confocal scanning.Seven 20-mer polypeptides from wild-type Vpu amino acid sequence were designed.Results:We report the design and identification of 3 novel anti-HIV-1 polypeptides that derived from Vpu se-quence which can efficiently inhibit HIV-1 infection.A pilot mechanism study showed that the active polypeptide could counteract Vpu-mediated tetherin downregulation.Laser confocal image scanning study showed that the polypeptides bound on the cell surface with a receptor specific binding manner,which may target tetherin that expressed on cell surface.Conclusion:Our work provided first evidence that counteracting Vpu-mediated tetherin downregulation could be a target for novel anti-HIV-1 drug design.Future works to provide direct evidence of inhibitors interact with teth-erin at atomic resolution and the development of small molecules inhibitors targeting Vpu-tetherin interactions may open a new avenue for novel antiretroviral therapy.展开更多
基金National Natural Science Foundation of China(11504435,61975062)National Key Research and Development Program of China(2019YFB2205202)Innovation Fund of WNLO.
文摘Multimode waveguide bend is one of the key components for realizing high-density mode-division multiplexing systems on chip.However,the reported multimode waveguide bends are either large,bandwidth-limited or fabrication-complicated,which hinders their applications in future high-density multimode photonic circuits.Here we propose a compact multimode waveguide bend supporting four TE modes simply by shape-optimizing with transformation optics.The shape of the waveguide is optimized in the virtual space with gradient distribution of the refractive index,so that the scattering loss and intermode cross talk are well suppressed.After conformal mapping back into the physical space,a compact(effective radius of 17μm)multimode bending waveguide is obtained.Simulations show that the proposed multimode waveguide bend has little loss(<0.1 dB)and low cross talk(<−20 dB)throughout an ultrabroad wavelength range of 1.16–1.66μm.We also fabricated the shape-optimized multimode bending waveguide on a silicon-on-insulator wafer.At 1550 nm wavelength,the measured excess losses for the four lowest-order TE modes are less than 0.6 dB,and the intermode cross talks are all below−17 dB.Our study paves the way for realizing high-density and large-scale multimode integrated optical circuits for optical interconnect.
文摘Background:HIV-1 Vpu acts by counteracting the tethering function of tetherin and resulting in the release of HIV-1 virion.Disrupting Vpu-tetherin interactions may provide a promising new target for antiretroviral therapy.Methods:Polypeptides that covered the amino acid sequence on the interface of Vpu-tetherin complex were designed.Phenotypic susceptibilities and cellular toxicities to the polypeptides were measured.The mechanisms of the anti-HIV-1 polypeptides were determined by the Western blot analysis and laser confocal scanning.Seven 20-mer polypeptides from wild-type Vpu amino acid sequence were designed.Results:We report the design and identification of 3 novel anti-HIV-1 polypeptides that derived from Vpu se-quence which can efficiently inhibit HIV-1 infection.A pilot mechanism study showed that the active polypeptide could counteract Vpu-mediated tetherin downregulation.Laser confocal image scanning study showed that the polypeptides bound on the cell surface with a receptor specific binding manner,which may target tetherin that expressed on cell surface.Conclusion:Our work provided first evidence that counteracting Vpu-mediated tetherin downregulation could be a target for novel anti-HIV-1 drug design.Future works to provide direct evidence of inhibitors interact with teth-erin at atomic resolution and the development of small molecules inhibitors targeting Vpu-tetherin interactions may open a new avenue for novel antiretroviral therapy.
