A Joint Delay-and-Sum and Fourier Beamforming Method for High Frame Rate Ultrasound Imaging

Frame rate is an important metric for ultrasound imaging systems,and high frame rates(HFR)benefit moving-target imaging.One common way to obtain HFR imaging is to transmit a plane wave.Delay-and-sum(DAS)beamformer is a conventional beamforming algorithm,which is simple and has been widely implemented in clinical application.Fourier beamforming is an alternative method for HFR imaging and has high levels of imaging efficiency,imaging speed,and good temporal dynamic characteristics.Nevertheless,the resolution and contrast performance of HFR imaging based on DAS or Fourier beamforming are insufficient due to the single plane wave transmission.To address this problem,a joint DAS and Fourier beamforming method is introduced in this study.The proposed method considers the different distributions of sidelobes in DAS imaging and Fourier imaging and combines the angular spectrum and DAS to reconstruct ultrasound images.The proposed method is evaluated on simulation and experimental phantom datasets to compare its performance with DAS and Fourier beamforming methods.Results demonstrate that the proposed method improves image effective dynamic range and resolution while also retaining a high frame rate of the ultrasound imaging systems.The proposed method improves the effective dynamic range along axial and lateral directions by 10 dB,compared to standard DAS and Fourier beamforming.

H_(2)O_(2)-sensitive nanoscale coordination polymers for photoacoustic tumors imaging via in vivo chromogenic assay

Photoacoustic(PA)imaging with much deeper tissue penetration and better spatial resolution had been widely employed for the prevention and diagnosis of many diseases.In this study,a new type of hydrogen peroxide(H_(2)O_(2)T-activated photoacoustic nanoprobe[Mn-AH nanoscale coordination polymer nanodots(NCPs)]was successfully synthesized by a simple one-step method in water phase containing 2,20-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS),horse radish peroxidase(HRP),and manganese ion(Mn^(2+).After modification by polyethylene glycol(PEG),Mn-AH NCPs exhibited excellent stability and biocompatibility for in vivo H_(2)O_(2)-responsive chromogenic assay with great speci¯city and sensitivity.In the presence of H_(2)O_(2),colorless ABTS would be converted by HRP into the oxidized form with strong near-infrared(NIR)absorbance,enabling photoacoustic detection of endogenous H_(2)O_(2).Using H_(2)O_(2)-activated Mn-AH NCPs,we have successfully performed PA imaging and H_(2)O_(2)detection of subcutaneous murine colon CT26 tumor and deep-seated orthotopic bladder tumor.Due to the inherent Mn element existence inside the Mn-AH,this nanoprobe also serves as a good T1-weighted magnetic resonance imaging(MRI)contrast agent simultaneously.Lastly,after accomplishing its imaging functions,the Mn-AH NCPs could be cleared out from the body without any long-term toxicity,providing a new opportunity for cancer diagnosis and treatment.

TDLens:Toward an Empirical Evaluation of Provenance Graph-Based Approach to Cyber Threat Detection

To combat increasingly sophisticated cyber attacks,the security community has proposed and deployed a large body of threat detection approaches to discover malicious behaviors on host systems and attack payloads in network traffic.Several studies have begun to focus on threat detection methods based on provenance data of host-level event tracing.On the other side,with the significant development of big data and artificial intelligence technologies,large-scale graph computing has been widely used.To this end,kinds of research try to bridge the gap between threat detection based on host log provenance data and graph algorithm,and propose the threat detection algorithm based on system provenance graph.These approaches usually generate the system provenance graph via tagging and tracking of system events,and then leverage the characteristics of the graph to conduct threat detection and attack investigation.For the purpose of deeply understanding the correctness,effectiveness,and efficiency of different graph-based threat detection algorithms,we pay attention to mainstream threat detection methods based on provenance graphs.We select and implement 5 state-of-the-art threat detection approaches among a large number of studies as evaluation objects for further analysis.To this end,we collect about 40GB of host-level raw log data in a real-world IT environment,and simulate 6 types of cyber attack scenarios in an isolated environment for malicious provenance data to build our evaluation datasets.The crosswise comparison and longitudinal assessment interpret in detail these detection approaches can detect which attack scenarios well and why.Our empirical evaluation provides a solid foundation for the improvement direction of the threat detection approach.

The combination of eddy thermal effect of biodegradable magnesium with immune checkpoint blockade shows enhanced efficacy against osteosarcoma

Osteosarcoma(OS)patients have a poor prognosis due to its high degree of heterogeneity and high rate of metastasis.Magnetic hyperthermia therapy(MHT)combined with immunotherapy is an effective strategy to treat solid and metastatic tumors.Here,we combined biodegradable magnesium(Mg)macroscale rods,which acted as an eddy thermo-magnetic agent under a low external alternating magnetic field,and immunotherapy to achieve a radical cure for OS.The eddy thermal effect(ETE)of the Mg rods(MgR)showed outstanding cytotoxic effects and enhanced the maturation of dendritic cells(DCs),and the mild MHT induced the immunogenic cell death(ICD)in the OS cells.Combined with immune checkpoint blockade(ICB)therapy,we obtained an excellent curative effect against OS,and a further evaluation demonstrated that the local MHT induced by the MgR increased T cells infiltration and the polarization of M1 macrophages.Interestingly,the biodegradable MgR also promoted bone osteogenesis.Our work highlighted the uneven ETE mediated by the biodegradable MgR induced a comprehensive immunologic activation in the OS tumor microenvironment(TME),which would inspire the application of MHT for the effective treatment of OS.

Evaluation on the applicability of ERA5 reanalysis dataset to tropical cyclones affecting Shanghai

Based on the 16 historical tropical cyclones(TCs)affecting Shanghai from 2007 to 2019,the suitability of ERA5 for studying TCs affecting Shanghai is systematically evaluated from the perspective of TC track,intensity,10-m and upper-level wind,using TC best-track data of China Meteorological Administration and surface observations and sounding data.Corresponding to tropical storm(TS),strong tropical storm(STS),typhoon(TY),strong typhoon(STY)and super typhoon(SuperTY),the median TC track bias is 68.1,52.9,42.5,25.4,and 18.2 km,respectively,the median maximum 10-m wind speed(VMAX10m)bias is-3.7,-6.5,-11.4,-21.7,and-32.2 m·s-1,respectively,and the median minimum mean sea level pressure(MSLPmin)bias is 2.2,5.6,8.1,28.2,and 48.7 hPa,respectively.With the increase of TC intensity,the median TC track bias decreases,while the median VMAX10m and MSLPmin bias increase.In general,VMAX10m in ERA5 is lower than observed,and MSLPmin is larger than observed.Under influence of TS,STS,TY and STY,the median 10-m wind speed(V10m)bias in the city is 3.2,4.2,4.7,and 5.4 m·s-1,respectively,and is 4.4-5.2 m·s-1 near the east coast,respectively.V10m is mostly biased high,showing an"M"type pattern with the distance between TC and Shanghai.The median 10 m wind direction(WD10m)bias is in a range of-7° to+7°.The median upper-level wind speed(Vupper)bias decreases with height,with a maximum of~5 m·s-1 at 975 hPa.Below 900 hPa Vupperin ERA5 is typically larger than the radiosonde observation,and its mean bias error(MBE)increases with TC intensity.The upper-level wind direction(WDupper)matches the sounding data well,with a maximum bias of a few degrees only.The results provide a reference for the application of ERA5 to coastal cities affected by TCs.

Ultrasmall iron-quercetin metal natural product nanocomplex with antioxidant and macrophage regulation in rheumatoid arthritis

Oxidative stress,due to the disruption of the balance between reactive oxygen species(ROS)generation and the antioxidant defense system,plays an important role in the pathogenesis of rheumatoid arthritis(RA).Excessive ROS leads to the loss of biological molecules and cellular functions,release of many inflammatory mediators,stimulate the polarization of macrophages,and aggravate the inflammatory response,thus promoting osteoclasts and bone damage.Therefore,foreign antioxidants would effectively treat RA.Herein,ultrasmall iron-quercetin natural coordination nanoparticles(Fe-Qur NCNs)with excellent anti-inflammatory and antioxidant properties were constructed to effectively treat RA.Fe-Qur NCNs obtained by simple mixing retain the inherent ability to remove ROS of quercetin and have a better water-solubility and biocompatibility.In vitro experiments showed that Fe-Qur NCNs could effectively remove excess ROS,avoid cell apoptosis,and inhibit the polarization of inflammatory macrophages by reducing the activation of the nuclear factor-κ-gene binding(NF-κB)pathways.In vivo experiments showed that the swollen joints of mice with rheumatoid arthritis treated with Fe-Qur NCNs significantly improved,with Fe-Qur NCNs largely reducing inflammatory cell infiltration,increasing antiinflammatory macrophage phenotypes,and thus inhibiting osteoclasts,which led to bone erosion.This study demonstrated that the new metal-natural coordination nanoparticles could be an effective therapeutic agent for the prevention of RA and other diseases associated with oxidative stress.

Effects of deficit irrigation on soil microorganisms and growth of Arabica coffee(Coffea arabica L.)under different shading cultivation modes

In the present research,the rational coupling mode of irrigation and shading cultivation for rapid growth and water saving of young Arabica coffee shrubs was investigated from 2016 to 2017.Taking full irrigation(FI,1.2Ep)as the control,the effects of three deficit irrigation(DI)(DI1,DI2 and DI3,with 1.0Ep,0.8Ep and 0.6Ep)on soil water content,temperature,microorganism population density,photosynthetic characteristics,canopy structure and dry mass of Arabica coffee under three shading cultivation modes(S0,monoculture coffee;S1,mild shading cultivation,intercropping with one line of Arabica coffee and one line of castor(Ricinus communis L.);S2,severe shading cultivation,intercropping with one line of Arabica coffee and two lines of castor)were investigated using plot experiments.Compared to FI,DI1 not obviously changed the population density of soil bacteria and actinomycetes,but increased net photosynthetic rate(Pn),crown area and dry mass of Arabica coffee by 7.0%,9.53%and 10.46%,respectively.In addition,DI1 also decreased total radiation under canopy(TRUC)by 5.51%.DI2 and DI3 reduced the population density of soil bacteria,fungi and actinomycetes ranging 8.94%-47.06%.Compared to S0,S1 increased the population density of soil fungi,bacteria and actinomycetes by 13.99%,30.77%and 9.72%,respectively.S1 also increased Pn,transpiration rate(Tr),leaf apparent radiation use efficiency(ARUE),leaf area index(LAI)and dry mass by 9.29%,5.39%,60.98%,10.31%and 30.02%,respectively.DI1S1 obtained the highest Pn and dry mass and higher LAI and the lowest TRUC.DI1S1 increased Pn,ARUE and dry mass by 18.98%,72.37%and 62.90%respectively but decreased TRUC by 21.77%when compared to FIS0.Thus,DI1S1 was found to be the rational mode of irrigation and shading cultivation for young Arabica coffee.

An anti-inflammatory and neuroprotective biomimetic nanoplatform for repairing spinal cord injury

Spinal cord regeneration after a spinal cord injury (SCI) remains a difficult challenge due to the complicated inflammatory microenvironment and neuronal damage at the injury sites. In this study, retinoic acid (RA) and curcumin (Cur) were co-loaded with bovine serum albumin (BSA) self-assembly to obtain RA@BSA@Cur nanoparticles (NPs) for SCI treatment. Cur, as an antioxidant drug, facilitated reactive oxygen species (ROS) scavenging, and decreased the amount of inflammatory factors secreted by macrophages, while RA could enhance neurite extensions and neural differentiation. The constructed RA@BSA@Cur NPs not only induced polarization of macrophages toward pro-regenerative phenotypes and markedly reduced the inflammatory response of macrophages or microglia, but also increased neurite length in PC12 cells and neuronal differentiation of bone marrow mesenchymal stem cells, improved the differentiation of neural stem cells (NSCs) into β3- tubulin+ neurons, and reversed the pro-astrocyte differentiation effect of inflammatory cytokines on NSCs. In vivo experiments revealed that RA@BSA@Cur NPs regulated the phenotypic polarization of macrophages, inhibited the release of inflammatory mediators, promoted functional neuron regeneration and motor function, and further inhibited scar tissue formation. This study highlighted that the BSA-based biomimetic nanomaterials could be used as ROS scavengers and nerve regeneration promoters for treating SCI.