Secure Transmissions in Wireless Multiuser Networks Using Message Correlation

Due to the openness of wireless multiuser networks,the private information transmitted in uplink or downlink is vulnerable to eavesdropping.Especially,when the downlink transmissions use nonorthogonal multiple access(NOMA)techniques,the system further encounters interior eavesdropping.In order to address these security problems,we study the secret communication in multiuser networks with both uplink and downlink transmissions.Specifically,in uplink transmissions,the private messages transmitted in each slot are correlated,so any loss of the private information at the eavesdropper will prevent the eavesdropper from decoding the private information in later time slots.In downlink transmissions,the messages are correlated to the uplink information.In this way,any unexpected users who lose the expected user’s uplink information cannot decode its downlink information.The intercept probability is used to measure security performance and we analyze it in theory.Finally,simulation results are provided to corroborate our theoretical analysis.

A novel modified paclitaxel-loaded discoidal recombinant high-density lipoproteins:Preparation,characterizations and in vivo evaluation

This study is one of the first to focus on the unexpected drug leakage from discoidal recombinant high-density lipoproteins(d-rHDLs)as a consequence of remodeling process,mainly associated with lecithin-cholesterol acyltransferase(LCAT)during their metabolic process.Here,a newly monocholesterylsuccinate(CHS)modified paclitaxel-loaded drHDLs(cP-d-rHDLs)were constructed successfully through structural modification,thus aiming to improve the performance of d-rHDLs.And next their in vitro physiochemical properties and pharmacokinetics in SpragueeDawley rats were elaborately investigated.Collectively our studies demonstrated that cP-d-rHDLs,whose remodeling behaviors were restrained effectively after structural modification,exhibited more excellent and promising properties as novel delivery vehicles for anti-cancer agents.

Reactive oxygen species(ROS)-responsive size-reducible nanoassemblies for deeper atherosclerotic plaque penetration and enhanced macrophage-targeted drug delivery

Nanoparticle-based therapeutics represent potential strategies for treating atherosclerosis;however,the complex plaque microenvironment poses a barrier for nanoparticles to target the dysfunctional cells.Here,we report reactive oxygen species(ROS)-responsive and size-reducible nanoassemblies,formed by multivalent host-guest interactions betweenβ-cyclodextrins(β-CD)-anchored discoidal recombinant high-density lipoprotein(NP^(3)_(ST))and hyaluronic acid-ferrocene(HA-Fc)conjugates.The HA-Fc/NP^(3)_(ST)nanoassemblies have extended blood circulation time,specifically accumulate in atherosclerotic plaque mediated by the HA receptors CD44 highly expressed in injured endothelium,rapidly disassemble in response to excess ROS in the intimal and release smaller NP^(3)_(ST),allowing for further plaque penetration,macrophage-targeted cholesterol efflux and drug delivery.In vivo pharmacodynamicses in atherosclerotic mice shows that HA-Fc/NP^(3)_(ST)reduces plaque size by 53%,plaque lipid deposition by 63%,plaque macrophage content by 62%and local inflammatory factor level by 64%compared to the saline group.Meanwhile,HA-Fc/NP^(3)_(ST)alleviates systemic inflammation characterized by reduced serum inflammatory factor levels.Collectively,HA-Fc/NP^(3)_(ST)nanoassemblies with ROS-responsive and size-reducible properties exhibit a deeper penetration in atherosclerotic plaque and enhanced macrophage targeting ability,thus exerting effective cholesterol efflux and drug delivery for atherosclerosis therapy.

新冠病毒核衣壳蛋白及其在病毒感染中的作用

新型冠状病毒感染引起的新冠肺炎传播已经导致了全世界数百万人的死亡。因此,深入了解新冠病毒的生物学基础对研发控制其传播的新手段至关重要。新冠病毒的核衣壳蛋白(N蛋白)是一个重要的诊断和治疗靶点,它在病毒生命周期中具有多种重要功能。目前已有多个关于新冠病毒N蛋白的结构与功能方面的研究报道。本综述总结了这个进化上高度保守的N蛋白的最新数据,以期提供有关该蛋白的结构和多种功能特征的全面信息。

Manipulating metal-insulator transitions of VO_(2) films via embedding Ag nanonet arrays

Manipulating metal-insulator transitions in strongly correlated materials is of great importance in condensed matter physics,with implications for both fundamental science and technology.Vanadium dioxide(VO_(2)),as an ideal model system,is metallic at high temperatures and shown a typical metal-insulator structural phase transition at 341 K from rutile structure to monoclinic structure.This behavior has been absorbed tons of attention for years.However,how to control this phase transition is still challenging and little studied.Here we demonstrated that to control the Ag nanonet arrays(NAs)in monoclinic VO_(2)(M)could be effective to adjust this metal-insulator transition.With the increase of Ag NAs volume fraction by reducing the template spheres size,the transition temperature(Tc)decreased from 68°C to 51°C.The mechanism of Tc decrease was revealed as:the carrier density increases through the increase of Ag NAs volume fraction,and more free electrons injected into the VO_(2)films induced greater absorption energy at the internal nanometal-semiconductor junction.These results supply a new strategy to control the metal-insulator transitions in VO_(2),which must be instructive for the other strongly correlated materials and important for applications.

A biomimetic nanocomposite with enzyme-like activities and CXCR4 antagonism efficiently enhances the therapeutic efficacy of acute myeloid leukemia

Despite the progress made to improve therapeutic outcomes for acute myeloid leukemia(AML),many unmet clinical needs remain to be resolved.Unlike existing anti-AML strategies,here we developed a biomimetic nanocomposite to efficiently eliminate the leukemia cells in the bone marrow and prevent the homing of AML.To fulfill our design,the ultra-small nanozyme was conjugated onto the surface of an oxygen-carrying nanoparticle,which was further coated with bone marrow stromal cell membrane.After entering the blood,this biomimetic nanocomposite got actively internalized by the leukemia cells in the blood and released the loaded chemotherapeutics and nanozyme inside the leukemia cells to achieve a synergistic antitumor efficacy.Meanwhile,the adhesive properties of the stromal cell membrane enabled the nanocomposite to home to the bone marrow,where the nanocomposite effectively killed the retained leukemia cells.More importantly,the biomimetic cell membrane also acted as a CXCR4 antagonism to block the CXCR4/CXCL12-mediated homing of leukemia cells to the bone marrow and infiltration to other organs like the liver and spleen.In conclusion,this proof-of-concept study demonstrated that our designed platform effectively kills leukemia cells while preventing their infiltration,thus providing a promising prospect for resolving the clinical challenges in current AML treatment.

THE HYDROSTATIC PIEZOELECTRICITY OF RELAXOR-PbTiO_(3)FERROELECTRIC CERAMICS AND CRYSTALS

The hydrostatic piezoelectricity of Pb(Mg_(1/3)Nb_(2/3))-αPbTiO_(3)(PMN-εPT)ceramics and PMN-0.32PT and Pb(Mg_(1/3)Nb_(2/3))-Pb(In_(1/2)Nb_(1/2))=PbTiO_(3)(PMN-PIN-PT)crystals wereinvestigated through a quasi-static method.The results showed that pressure-induced depolar-ization occurred in PMN-εPT ceramics when pressure was above about 50 MPa,while there wasno obvious pressure-induced depolarization for PMN-0.32PT and PMN-PIN-PT crystals inthe whole pressure range(0~530 MPa).The hydrostatic piezoelectric coeficient dh of PMN-0.32PT and PMN-PIN-PT crystals was nearly independent of pressure.The d_(h)of mono-domain orthorhombic and tetragonal phase crystals is slightly larger,on the order of 100 pC/N.In addition,the relationship between the hydrostatic piezoelectric coeficient d_(h)and the longit udinal and transverse piezoelectric coefficients d_(33)and d_(31)for different crystal systems was summarized.

Serum IgA,IgM,and IgG responses in COVID-19

Currently,detecting SARS-CoV-2 RNAs is a standard approach for COVID-19 diagnosis.However,there is an urgent need for reliable and rapid serological diagnostic methods to screen SARS-CoV-2-infected people including those who do not have overt symptoms.Most emerging studies described serological tests based on detection of SARS-CoV-2-specific IgM and IgG.1–4 Although detection of SARS-CoV-2-specific IgA in serum has been reported in few papers,5,6 analyses of IgA levels in a larger number of COVID-19 patients are still lacking.

Energy-efficient data collection for UAV-assisted IoT: Joint trajectory and resource optimization

Internet of Things(IoT) can be conveniently deployed while empowering various applications, where the IoT nodes can form clusters to finish certain missions collectively. As energyefficient operations are critical to prolong the lifetime of the energy-constrained IoT devices, the Unmanned Aerial Vehicle(UAV) can be dispatched to geographically approach the IoT clusters towards energy-efficient IoT transmissions. This paper intends to maximize the system energy efficiency by considering both the IoT transmission energy and UAV propulsion energy, where the UAV trajectory and IoT communication resources are jointly optimized. By applying largesystem analysis and Dinkelbach method, the original fractional optimization is approximated and reformulated in the form of subtraction, and further a block coordinate descent framework is employed to update the UAV trajectory and IoT communication resources iteratively. Extensive simulation results are provided to corroborate the effectiveness of the proposed method.

Enhancing physical-layer security via big-data-aided hybrid relay selection

The explosive growth in data trac presents new challenges to the new generation of wireless communication systems,such as computing capabilities,spectrum eciency and security.In this paper,we use the network structure,which is adaptable for the big data trac,to improve the security of wireless networks.Speci cally,a big-data aided hybrid relay selection scheme is designed and analyzed to enhance physical layer security.First,considering the ideal situation that an eavesdropper's CSI(Channel State Information)is known to the legal nodes,we propose an optimal hybrid relay selection scheme consisting of the optimal mode selection scheme and the optimal relay selection scheme.In this case,we analyze the upper bound of an eavesdropper's capacity in FD(Full-Duplex)mode and the secrecy outage probabilities of the optimal HD(Half-Duplex),FD,and hybrid relay selection schemes.Through the analysis of data,it is clear that the mode selection is decided by the self-interference of the FD technique.However,the instantaneous CSI of an eavesdropper is dicult to obtain due to the passive characteristic of eavesdroppers in practice.Therefore,a more practical hybrid relay selection scheme with only the channel distribution information of an eavesdropper is further studied,where a weighting factor is employed to guarantee that the hybrid mode is no worse than either the FD mode or HD mode when the self-interference grows.Finally,the simulation results show the improved security of our proposed scheme.