433 research outputs found

    Phase-Matching Quantum Key Distribution without Intensity Modulation

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    Quantum key distribution provides a promising solution for sharing secure keys between two distant parties with unconditional security. Nevertheless, quantum key distribution is still severely threatened by the imperfections of devices. In particular, the classical pulse correlation threatens security when sending decoy states. To address this problem and simplify experimental requirements, we propose a phase-matching quantum key distribution protocol without intensity modulation. Instead of using decoy states, we propose a novel method to estimate the theoretical upper bound on the phase error rate contributed by even-photon-number components. Simulation results show that the transmission distance of our protocol could reach 305 km in telecommunication fiber. Furthermore, we perform a proof-of-principle experiment to demonstrate the feasibility of our protocol, and the key rate reaches 22.5 bps under a 45 dB channel loss. Addressing the security loophole of pulse intensity correlation and replacing continuous random phase with 6 or 8 slices random phase, our protocol provides a promising solution for constructing quantum networks.Comment: Comments are welcome! 12 pages, 6 figure

    Simple security proof of coherent-one-way quantum key distribution

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    Coherent-one-way quantum key distribution (COW-QKD), which requires a simple experimental setup and has the ability to withstand photon-number-splitting attacks, has been not only experimentally implemented but also commercially applied. However, recent studies have shown that the current COW-QKD system is insecure and can only distribute secret keys safely within 20 km of the optical fiber length. In this study, we propose a practical implementation of COW-QKD by adding a two-pulse vacuum state as a new decoy sequence. This proposal maintains the original experimental setup as well as the simplicity of its implementation. Utilizing detailed observations on the monitoring line to provide an analytical upper bound on the phase error rate, we provide a high-performance COW-QKD asymptotically secure against coherent attacks. This ensures the availability of COW-QKD within 100 km and establishes theoretical foundations for further applications.Comment: 8 pages, 5 figures, 1 tabl

    Nanoparticles of Poly(Lactide-Co-Glycolide)-d-a-Tocopheryl Polyethylene Glycol 1000 Succinate Random Copolymer for Cancer Treatment

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    Cancer is the leading cause of death worldwide. Nanomaterials and nanotechnologies could provide potential solutions. In this research, a novel biodegradable poly(lactide-co-glycolide)-d-a-tocopheryl polyethylene glycol 1000 succinate (PLGA-TPGS) random copolymer was synthesized from lactide, glycolide and d-a-tocopheryl polyethylene glycol 1000 succinate (TPGS) by ring-opening polymerization using stannous octoate as catalyst. The obtained random copolymers were characterized by 1H NMR, FTIR, GPC and TGA. The docetaxel-loaded nanoparticles made of PLGA-TPGS copolymer were prepared by a modified solvent extraction/evaporation method. The nanoparticles were then characterized by various state-of-the-art techniques. The results revealed that the size of PLGA-TPGS nanoparticles was around 250 nm. The docetaxel-loaded PLGA-TPGS nanoparticles could achieve much faster drug release in comparison with PLGA nanoparticles. In vitro cellular uptakes of such nanoparticles were investigated by CLSM, demonstrating the fluorescence PLGA-TPGS nanoparticles could be internalized by human cervix carcinoma cells (HeLa). The results also indicated that PLGA-TPGS-based nanoparticles were biocompatible, and the docetaxel-loaded PLGA-TPGS nanoparticles had significant cytotoxicity against Hela cells. The cytotoxicity against HeLa cells for PLGA-TPGS nanoparticles was in time- and concentration-dependent manner. In conclusion, PLGA-TPGS random copolymer could be acted as a novel and promising biocompatible polymeric matrix material applicable to nanoparticle-based drug delivery system for cancer chemotherapy

    Investigation of the Anti-Inflammatory Activity of Fusaproliferin Analogues Guided by Transcriptome Analysis

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    Background: Excessive inflammation results in severe tissue damage as well as serious acute or chronic disorders, and extensive research has focused on finding new anti-inflammatory hit compounds with safety and efficacy profiles from natural products. As promising therapeutic entities for the treatment of inflammation-related diseases, fusaproliferin and its analogs have attracted great interest. However, the underlying anti-inflammatory mechanism is still poorly understood and deserves to be further investigated.Methods: For the estimation of the anti-inflammatory activity of fusaproliferin (1) and its analogs (2-4)in vitro and in vivo, lipopolysaccharide (LPS)-induced RAW264.7 macrophages and zebrafish embryos were employed. Then, transcriptome analysis was applied to guide subsequent western blot analysis of critical proteins in related signaling pathways. Surface plasmon resonance assays (SPR) combined with molecular docking analyses were finally applied to evaluate the affinity interactions between 1-4 and TLR4 and provide a possible interpretation of the downregulation of related signaling pathways.Results: 1-4 significantly attenuated the production of inflammatory messengers, including nitric oxide (NO), reactive oxygen species (ROS), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β), as well as nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), in LPS-induced RAW264.7 macrophages. Transcriptome analyses based on RNA-seq indicated the ability of compound 1 to reverse LPS stimulation and the nuclear factor kappa-B (NF-κB) and mitogen-activated protein kinase (MAPKs) signaling pathways contribute to the anti-inflammatory process. Experimental verification at the protein level revealed that 1 can inhibit the activation of inhibitor of NF-κB kinase (IKK), degradation of inhibitor of NF-κB (IκB), and phosphorylation of NF-κB and reduce nuclear translocation of NF-κB. 1 also decreased the phosphorylation of MAPKs, including p38, extracellular regulated protein kinases (ERK), and c-Jun N-terminal kinase (JNK). SPR assays and molecular docking results indicated that 1-4 exhibited affinity for the TLR4 protein with KD values of 23.5–29.3 μM.Conclusion: Fusaproliferin and its analogs can be hit compounds for the treatment of inflammation-associated diseases

    Exemestane Attenuates Hepatic Fibrosis in Rats by Inhibiting Activation of Hepatic Stellate Cells and Promoting the Secretion of Interleukin 10

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    Exemestane (EXE) is an irreversible steroidal aromatase inhibitor mainly used as an adjuvant endocrine therapy for postmenopausal women suffering from breast cancer. Besides inhibiting aromatase activity, EXE has multiple biological functions, such as antiproliferation, anti-inflammatory, and antioxidant activities which are all involved in hepatic fibrosis. Therefore, we investigated the role of EXE during the progress of hepatic fibrosis. The effect of EXE on liver injury and fibrosis were assessed in two hepatic fibrosis rat models, which were induced by either carbon tetrachloride (CCl4) or bile duct ligation (BDL). The influence of EXE treatment on activation and proliferation of primary rat hepatic stellate cells (HSCs) was observed in vitro. The results showed that EXE attenuated the liver fibrosis by decreasing the collagen deposition and α-SMA expression in vivo and inhibited the activation and proliferation of primary rat HSCs in vitro. Additionally, EXE promoted the secretion of antifibrotic and anti-inflammatory cytokine IL-10 in vivo and in HSC-T6 culture media. In conclusion, our findings reveal a new function of EXE on hepatic fibrosis and prompted its latent application in liver fibrotic-related disease

    A long-term cohort study: the immune evasion and decreasing neutralization dominated the SARS-CoV-2 breakthrough infection

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    Most of vaccinees and COVID-19 convalescents can build effective anti-SARS-CoV-2 humoral immunity, which helps preventing infection and alleviating symptoms. However, breakthrough viral infections caused by emerging SARS-CoV-2 variants, especially Omicron subvariants, still pose a serious threat to global health. By monitoring the viral infections and the sera neutralization ability of a long-tracked cohort, we found out that the immune evasion of emerging Omicron subvariants and the decreasing neutralization led to the mini-wave of SARS-CoV-2 breakthrough infections. Meanwhile, no significant difference had been found in the infectivity of tested SARS-CoV-2 variants, even though the affinity between human angiotensin-converting enzyme 2 (hACE2) and receptor-binding domain (RBDs) of tested variants showed an increasing trend. Notably, the immune imprinting of inactivated COVID-19 vaccine can be relieved by infections of BA.5.2 and XBB.1.5 variants sequentially. Our data reveal the rising reinfection risk of immune evasion variants like Omicron JN.1 in China, suggesting the importance of booster with updated vaccines
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