3D Localization for Multiple AUVs in Anchor-Free Environments by Exploring the Use of Depth Information

Dear Editor,This letter investigates the cooperative localization problem for multiple autonomous underwater vehicles(AUVs)in underwater anchor-free environments,where AUV localization errors grow without bound due to the accumulated errors in inertial measurements(termed accumulated errors hereafter)and the lack of anchors(with known positions).

Current-Aided Multiple-AUV Cooperative Localization and Target Tracking in Anchor-Free Environments

In anchor-free environments,where no devices with known positions are available,the error growth of autonomous underwater vehicle(AUV)localization and target tracking is unbounded due to the lack of references and the accumulated errors in inertial measurements.This paper aims to improve the localization and tracking accuracy by involving current information as extra references.We first integrate current measurements and maps with belief propagation and design a distributed current-aided message-passing scheme that theoretically solves the localization and tracking problems.Based on this scheme,we propose particle-based cooperative localization and target tracking algorithms,named CaCL and CaTT,respectively.In AUV localization,CaCL uses the current measurements to correct the predicted and transmitted position information and alleviates the impact of the accumulated errors in inertial measurements.With target tracking,the current maps are applied in CaTT to modify the position prediction of the target which is calculated through historical estimates.The effectiveness and robustness of the proposed methods are validated through various simulations by comparisons with alternative methods under different trajectories and current conditions.

What leads to readers' satisfaction with the mobile news apps service? An investigation into the roles of content originality and user experience

Purpose: This study aims to explore whether content originality and user experience have positive effects on online news readers’ satisfaction with the mobile apps service.Design/methodology/approach: Data was collected via a Web-based survey. Data analysis of this study can be divided into two stages. In the first stage, a descriptive statistical analysis was conducted based on a sample of 612 respondents. In the second stage, the correlation among content originality, user experience and satisfaction was analyzed based on a sample of 377 mobile news apps users. Findings: Results of the first stage showed that social media and mobile news apps were the most important tools for users to access news, and different types of media were playing complementary roles in information transmission. Users held a positive attitude toward their mobile news reading experience and they described news they read on mobile apps with such words as "interesting", "instant", "positive", "profound", and "ironic". Results of the second stage confirmed our hypothesis that content originality and user experience both had positive impacts on user satisfaction.Research limitations: The questionnaires were distributed entirely online, so the sample may not be representative of the general population being studied and thus undermine the reliability and generalization of the findings to some extent. Moreover, this study adopted only one method(survey) and more methods such as interviews can be used to improve the accuracy of the results.Practical implications: The findings of this study can not only provide insights into a better understanding of users’ mobile reading behavior, but also help mobile information service providers attract more users.Originality/value: This is one of the first studies to explore the effects of content originality and user experience on online news readers’ satisfaction with the mobile apps service.

Magnesium metal and its corrosion products:Promising materials for tumor interventional therapy

Magnesium is generally known to degrade in aqueous environments by an electrochemical reaction.The corrosion products of magnesium include hydrogen gas,Mg^(2+),and Mg(OH)_(2).Here,we summarize the published literature describing the corrosion characteristics of magnesium,and the antitumor properties of magnesium-associated corrosion products,aiming to induce the therapeutic properties of magnesium and magnesium alloys in solid tumors.The therapeutic potential of corrosion products of magnesium is enormous.Hydrogen gas exhibits antioxidant and anti-inflammatory properties,which amount to potential anti-tumor characteristics.Mg(OH)_(2),which creates a localized alkaline microenvironment,represents a second approach for anti-tumor therapy with magnesium metal.Upregulated concentrations of Mg^(2+)ions in the local tumor microenvironment remodelling are considered a third approach for anti-tumor therapy.Therefore,we speculate about the different physical forms of magnesium that could create an anti-tumor microenvironment upon tumor interventional therapy,a technique that precisely places anti-tumor implants like particles and stents.Finally,we present our viewpoints on the potential use of magnesium in diverse solid tumor therapies to inhibit tumor progression.

DNA methylation mediated by RdDM pathway and demethylation affects furanone accumulation through regulation of QUINONE OXIDOREDUCTASE in strawberry

Recently,increasing evidence suggests that DNA methylation plays a crucial role in fruit ripening.However,the role of DNA methylation in regulating specific traits,such as flavor,remains unclear.Here,we report a role of DNA methylation in affecting furanone biosynthesis in strawberry.Strawberry quinone oxidoreductase(FaQR)is a key enzyme in furanone biosynthesis.There are four FaQR homologs in strawberry cultivar‘Yuexin’,and one of them,FaQR3,contributes∼50%of FaQR transcripts,indicating a major role of FaQR3 in furanone biosynthesis.Through characterization of levels of DNA methylation and FaQR3 transcript and furanone contents during fruit ripening and after the application of DNA methylation inhibitor,we found that the DNA methylation level of the FaQR3 promoter was negatively correlated with FaQR3 expression and furanone accumulation,suggesting that DNA methylation may be involved in furanone biosynthesis through adjusting FaQR3 expression,and responded to different temperatures consistently.In addition,transient expression of a gene in the RNA-directed DNA methylation(RdDM)pathway,FaAGO4,and enrichment analysis of the 24-nucleotide siRNAs suggested that DNA methylation in the FaQR3 promoter is mediated by the RdDM pathway.Transient RNA interference(RNAi)of FaDML indicated that the demethylation pathway may be involved in regulating furanone accumulation.These findings provide new insights into the role of DNA methylation and demethylation in affecting flavor quality in strawberry during fruit ripening.

Solid particle size characterization by a high-frequency collision response in pneumatic particulate flow

A novel triaxial vibration method is developed for the real-time characterization of the solid particle size distribution(PsD)in pneumatic particulate flow,which is critical for chemical industry.In this work,the particle-wall collision and friction behaviours were analysed by the time-domain statistical and timefrequency joint methods to narrow the high-frequency response range by the initial experiment of free fall for a single particle,interparticle,and multiple particles.Subsequently,verification experiments of PSD characterization in pneumatic flow were performed.First,the quantitative triaxial energy response model that considers the particle size,shape,and mass factors were established.Second,a good agreement of the particle number identification was found between the triaxial vibration energy and mean particle size of 150-550μm.Moreover,the performance with the best accuracy was focused on a range of 42-43 kHz in the x-axis and z-axis and 36.8-38.8 kHz in the y-axis.Finally,the individual particle energy was inversely analysed by the triaxial vibration response within the optimized frequency bands,and the PSD was characterized in real-time by a low error rate,that is,5.2% from the XZ-axis direction of sand(42-43 kHz)and 5.6% from the XYZ-axis of glass(30.9-33.9 kHz,46.2-47.2 kHz,38.3-41.3 kHz for each axis response).Therefore,this research complements the existing approaches for PsD characterization in particulate multiphase flow.

Natural gas consumption forecasting model based on coal-to-gas project in China

Natural gas is widely used because it is environmentally friendly,particularly in reducing carbon emission and improving the Air Quality Index(AQI)around densely populated cities.China has initiated a coal-to-gas project(CGP)to improve the air quality in northern China.As a subcompany of China National Petroleum Corporation,PetroChina Natural Gas Marketing North Company has been focusing on natural gas resource allocation while considering numerous issues such as ensuring the bottom line of livelihood requirements in winter and the performance of economic indicators for an entire calendar year in the northern part of China.Therefore,the accurate prediction of natural gas consumption is important to PetroChina Natural Gas Marketing North Company.It has become a challenge to forecast natural gas consumption because the natural gas market has changed considerably because of the CGP.Natural gas consumption cannot be forecasted using conventional models.This study analyzes the characteristics of the CGP based on the data obtained from rural individual users and company users.Based on the analysis,the gas consumption in winter is predicted using two different forecasting approaches.The methods presented in this paper provide a basis for formulating effective measures for natural gas scheduling in the northern part of China.

Secreted LRPAP1 binds and triggers IFNAR1 degradation to facilitate virus evasion from cellular innate immunity

variety of ways to antagonize host defense through eliminating IFN-signaling intracellularly for decades.However,the way by viruses target IFN-signaling extracellularly has not been discovered.Infection by both coronavirus SARS-CoV-2 and enterovirus 71(EV71 or EV-A71)can cause severe diseases such as neurological disorders and even death in children.

An integrative protocol for one‑step PCR amplicon library construction and accurate demultiplexing of pooled sequencing data

High-throughput sequencing of amplicons has been widely used to precisely and efficiently identify species compositions and analyze community structures,greatly promoting biological studies involving large amounts of complex samples,especially those involving environmental and pathogen-monitoring ones.Commercial library preparation kits for amplicon sequencing,which generally require multiple steps,including adapter ligation and indexing,are expensive and time-consuming,especially for applications at a large scale.To overcome these limitations,a“one-step PCR approach”has been previously proposed for constructions of amplicon libraries using long fusion primers.However,efficient amplifications of target genes and accurate demultiplexing of pooled sequencing data remain to be addressed.To tackle these,we present an integrative protocol for one-step PCR amplicon library construction(OSPALC).High-quality reads have been generated by this approach to reliably identify species compositions of mock bacterial communities and environmental samples.With this protocol,the amplicon library is constructed through one regular PCR with long primers,and the total cost per DNA/cDNA sample decreases to just 7%of the typical cost via the multi-step PCR approach.Empirically tested primers and optimized PCR conditions to construct OSPALC libraries for 16S rDNA V4 regions are demonstrated as a case study.Tools to design primers targeting at any genomic regions are also presented.In principle,OSPALC can be readily applied to construct amplicon libraries of any target genes using DNA or RNA samples,and will facilitate research in numerous fields.

类施主效应调控与高择优取向织构提升n型Bi_(2)(Te,Se)_(3)材料热电性能

Thermoelectric materials have a wide range of application because they can be directly used in refrigeration and power generation. And the Bi_(2)Te_(3) stand out because of its excellent thermoelectric performance and are used in commercial thermoelectric devices. However, n-type Bi_(2)Te_(3) has seriously hindered the development of Bi_(2)Te_(3)-based thermoelectric devices due to its weak mechanical properties and inferior thermoelectric performance. Therefore, it is urgent to develop a high-performance n-type Bi_(2)Te_(3) polycrystalline. In this work, we employed interstitial Cu and the hot deformation process to optimize the thermoelectric properties of Bi_(2)Te_(2.7)Se_(0.3), and a high-performance thermoelectric module was fabricated based on this material. Our combined theoretical and experimental effort indicates that the interstitial Cu reduce the defect density in the matrix and suppresses the donor-like effect, leading to a lattice plainification effect in the material. In addition, the two-step hot deformation process significantly improves the preferred orientation of the material and boosts the mobility. As a result, a maximum ZT of 1.27 at 373 K and a remarkable high ZT_(ave) of 1.22 across the temperature range of 300–425 K are obtained. The thermoelectric generator(TEG, 7-pair) and thermoelectric cooling(TEC, 127-pair) modules were fabricated with our n-type textured Cu_(0.01)Bi_(2)Te_(2.7)Se_(0.3) coupled with commercial p-type Bi_(2)Te_(3). The TEC module demonstrates superior cooling efficiency compared with the commercial Bi_(2)Te_(3) device, achieving a ΔT of 65 and 83.4 K when the hot end temperature at 300 and 350 K, respectively. In addition, the TEG module attains an impressive conversion efficiency of 6.5% at a ΔT of 225 K, which is almost the highest value among the reported Bi_(2)Te_(3)-based TEG modules.

Altered gut microbiome in FUT2 loss-of-function mutants in support of personalized medicine for inflammatory bowel diseases

The FUT2 loss-of-function mutations are highly prevalent and are associated with inflammatory bowel disease(IBD).To investigate the impact of FUT2 loss-of-function mutation on the gut microbiota in patients with IBD,81 endoscopically confirmed IBD patients were genotyped and divided into 3 groups:homozygous for functional FUT2 genes(SeSe),with one copy of non-functional FUT2 gene(Sese),or homozygous for non-functional FUT2 genes(sese).Escherichia,which attaches to fucosylated glycoconjugates,was the only abundant genus exhibiting decreased abundance in sese patients.Compared with SeSe or Sese patients,sese patients exhibited higher abundance in CD8+inducing Alistipe and Phascolarctobacterium and Th17 inducing Erysipelotrichaceae UCG-003.Counter-intuitively,butyrate-producing bacteria were more abundant in sese patients.Consistently,metabolomics analysis found higher levels of butyrate in sese patients.Our data support the hypothesis that FUT2 loss-of-function mutation participates in the IBD pathogenesis by decreasing binding sites for adherent bacteria and thus altering the gut microbiota.Decreased abundances of adherent bacteria may allow the overgrowth of bacteria that induce inflammatory T cells,leading to intestinal inflammation.As FUT2 loss-of-function mutations are highly prevalent,the identification of T cell inducing bacteria in sese patients could be valuable for the development of personalized microbial intervention for IBD.

JUNO sensitivity on proton decay p→νK^(+)searches

The Jiangmen Underground Neutrino Observatory(JUNO)is a large liquid scintillator detector designed to explore many topics in fundamental physics.In this study,the potential of searching for proton decay in the p→νK^(+)mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification.Moreover,the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals.Based on these advantages,the detection efficiency for the proton decay via p→νK^(+)is 36.9%±4.9%with a background level of 0.2±0.05(syst)±0.2(stat)events after 10 years of data collection.The estimated sensitivity based on 200 kton-years of exposure is 9.6×1033 years,which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies.

Comparative WGBS identifies genes that influence non-ripe phenotype in tomato epimutant Colourless non-ripening

Whole-genome bisulfite sequencing(WGBS)allows single-base resolution and genome-wide profiling of DNA methylation in plants and animals.This technology provides a powerful tool to identify genes that are potentially controlled by dynamic changes of DNA methylation and demethylation.However,naturally occurring epimutants are rare and genes under epigenetic regulation as well as their biological relevances are often difficult to define.In tomato,fruit development and ripening are a complex process that involves epigenetic control.We have taken the advantage of the tomato epimutant Colourless non-ripening(Cnr)and performed comparative mining of the WGBS datasets for the Cnr and Sl CMT3-silenced Cnr fruits.We compared DNA methylation profiles for the promoter sequences of approximately 5,000 bp immediately upstream of the coding region of a list of20 genes.Differentially methylated regions were found for some of these genes.Virus-induced gene silencing(VIGS)of differentially methylated gene Sl DET1 or Sl PDS resulted in unusual brown pigmentation in Cnr fruits.These results suggest that comparative WGBS coupled with VIGS can be used to identify genes that may contribute to the colourless unripe phenotype of fruit in the Cnr epimutant.

Novel HDAC5-interacting motifs of Tbx3 are essential for the suppression of E-cadherin expression and for the promotion of metastasis in hepatocellular carcinoma

Tbx3,a transcriptional repressor,is essential in the organogenesis of vertebrates,stem cell self-renewal and differentiation,and the carcinogenesis of multiple tumor types.However,the mechanism by which Tbx3 participates in the metastasis of hepatocellular carcinoma(HCC)remains largely unknown.In this study,we show that Tbx3 was dramatically upregulated in clinical HCC samples and that elevated expression of Tbx3 promoted cancer progression.To determine the underlying mechanism,systematic glycine scan mutagenesis and deletion assays were performed.We identified two critical motifs,^(585)LFSYPYT^(591)and^(604)HRH^(606),that contribute to the repression of transcriptional activity.These motifs are also essential for Tbx3 to promote cell migration and metastasis both in vitro and in vivo via the suppression of E-cadherin expression.More importantly,Tbx3 directly interacts with HDAC5 via these motifs,and an HDAC inhibitor blocks Tbx3-mediated cell migration and the downregulation of E-cadherin in HCC.As Tbx3 is involved in the carcinogenesis of multiple types of human cancers,our findings suggest an important target for anticancer drug development.

A leakage particle-wall impingement based vibro-acoustic characterization of the leaked sand-gas pipe flow

Solid particle leakage detection in double-wall pipes is industrially important,especially in chemical and petroleum engineering.Here,we developed vibration and acoustic sensor approaches for the characterization and comparative study of the applicability of leakage sand particle detection from the flow of gas pipes.A specific wideband vibration sensor and pressure-field microphone were selected to identify the vibro-acoustic characteristics within 50 kHz of the particle leakage.The vibro-acoustic time-behaviours and characteristic frequencies of particle leakage were observed by the time-frequency method.The leakage gas flow noise was verified by coherence analysis and minimized by a digital bandpass and band-elimination filter.Corresponding experiments were performed,and good agreement was found between the release pressures(0.1-0.3 MPa)with different leak sizes(0-8 mm)under different sand masses(120μm)and vibro-acoustic Root-Mean-Square(RMS)levels.In the comparison of the two methods,the vibration method has a better frequency response for the leakage flow and is good for identifying whether there are particle leaks.The acoustic method has a time behaviour response and is good for establishing the relationship between the particle mass and signals.In addition,the acoustic method has frequency shift features with a better signal to noise ratio.The acoustic method lays the foundation for future work of more complex leakage detection combining the advantages of vibration and the acoustic method.

SARS-CoV-2 impairs the disassembly of stress granules and promotes ALS-associated amyloid aggregation

The nucleocapsid(N)protein of SARS-CoV-2 has been reported to have a high ability of liquid-liquid phase separation,which enables its incorporation into stress granules(SGs)of host cells.However,whether SG invasion by N protein occurs in the scenario of SARS-CoV-2 infection is unknow,neither do we know its con-sequence.Here,we used SARS-CoV-2 to infect mam-malian cells and observed the incorporation of N protein into SGs,which resulted in markedly impaired self-dis-assembly but stimulated cell cellular clearance of SGs.NMR experiments further showed that N protein binds to the SG-related amyloid proteins via non-specific tran-sient interactions,which not only expedites the phase transition of these proteins to aberrant amyloid aggre-gation in vitro,but also promotes the aggregation of FUS with ALS-associated P525L mutation in cells.In addition,we found that ACE2 is not necessary for the infection of SARS-CoV-2 to mammalian cells.Our work indicates that SARS-CoV-2 infection can impair the dis-assembly of host SGs and promote the aggregation of SG-related amyloid proteins,which may lead to an increased risk of neurodegeneration.

Sub-percent precision measurement of neutrino oscillation parameters with JUNO

JUNO is a multi-purpose neutrino observatory under construction in the south of China.This publication presents new sensitivity estimates for the measurement of the △m_(31)^(2),△m_(21)^(2),sin^(2)θ_(12),and sin^(2)θ_(13) oscillation parameters using reactor antineutrinos,which is one of the primary physics goals of the experiment.The sensitivities are obtained using the best knowledge available to date on the location and overburden of the experimental site,the nuclear reactors in the surrounding area and beyond,the detector response uncertainties,and the reactor antineutrino spectral shape constraints expected from the TAO satellite detector.It is found that the △m_(21)^(2) and sin^(2)θ_(12) oscillation parameters will be determined to 0.5%precision or better in six years of data collection.In the same period,the △m_(31)^(2) parameter will be determined to about 0.2%precision for each mass ordering hypothesis.The new precision represents approximately an order of magnitude improvement over existing constraints for these three parameters.

Vortex excites unidirectional water waves near ancient Luoyang Bridge

Since the discovery of generalized Snell’s law in 2011[1],metasurfaces have opened up the mainstream of arbitrary wavefront manipulation in electromagnetism.Using a gradient-index metasurface,the parallel wavenumber kx of reflected wave can be not equal to the incident one(kx=ξ+k0sinθi,where k0 andθi are the incident wavenumber and angle,andξis the phase gradient of metasurface in its supercell)[1].Whenξ>k0,the reflected wave becomes a surface wave bounded on the metasurface(where|kx|>k0,kz is imaginary,and z is normal to the metasurface)[2].However,as research of metasurfaces continually evolves,some articles have pointed out that such graded metasurfaces suffer from a series of problems[3-6].In particular,multiple metallic resonators are adopted in a subwavelength supercell,resulting in impedance mismatch,moderate conversion efficiency,wave absorption,and fabrication complexity.Hence,although the approach of graded metasurfaces has been demonstrated in the microwave regime,it is hard to extend to infrared and optical ranges with shorter wavelengths.To solve this problem,Ra’di et al.[7]devised metagratings with periodic arrays of bianisotropic scatterers and showed that they enable wave front engineering with unitary efficiency and significantly lower fabrication demands.