Satellite-Air-Terrestrial Cloud Edge Collaborative Networks:Architecture,Multi-Node Task Processing and Computation

Integrated satellite-terrestrial network(ISTN)has been considered a novel network architecture to achieve global three-dimensional coverage and ultra-wide area broadband access anytime and anywhere.Being a promising paradigm,cloud computing and mobile edge computing(MEC)have been identified as key technology enablers for ISTN to further improve quality of service and business continuity.However,most of the existing ISTN studies based on cloud computing and MEC regard satellite networks as relay networks,ignoring the feasibility of directly deploying cloud computing nodes and edge computing nodes on satellites.In addition,most computing tasks are transferred to cloud servers or offloaded to nearby edge servers,the layered design of integrated satellite-air-terrestrial architecture and the cloud-edge-device cooperative processing problems have not been fully considered.Therefore,different from previous works,this paper proposed a novel satellite-air-terrestrial layered architecture for cloud-edge-device collaboration,named SATCECN.Then this paper analyzes the appropriate deployment locations of cloud servers and edge servers in ISTN,and describes the processing flow of typical satellite computing tasks.For computing resource allocation problems,this paper proposed a device-edge-cloud Multi-node Cross-layer Collaboration Computing(MCCC)method to find the optimal task allo-cation strategy that minimizes the task completion delay and the weighted system energy consumption.Furthermore,the approximate optimal solutions of the optimization model are obtained by using successive convex approxi-mation algorithm,and the outstanding advantages of the proposed method in reducing system energy consumption and task execution delay are verified through experiments.Finally,some potential issues and directions for future research are highlighted.

Quasi-static simulation of droplet morphologies using a smoothed particle hydrodynamics multiphase model

Numerical simulation of the morphology of a droplet deposited on a solid surface requires an efficient description of the three-phase contact line. In this study, a simple method of implementing the contact angle is proposed, combined with a robust smoothed particle hydrodynamics multiphase algorithm (Zhang 2015). The first step of the method is the creation of the virtual liquid-gas interface across the solid surface by means of dummy particles, thus the calculated surface tension near the triple point serves to automatically modulate the dynarnic contact line towards the equilibrium state. We simulate the evolution process of initially square liquid lumps on fiat and curved surfaces. The predictions of droplet profiles are in good agreement with the analytical solutions provided that the macroscopic contact angle is accurately implemented. Compared to the normal correction method, the present method is straightforward without the need to manually alter the normal vectors. This study presents a robust algorithm capable of capturing the physics of the static welling. It may hold great potentials in bio-inspired superhydrophobic surfaces, oil displacement, microfluidics, ore floatation, etc.

Modeling rock fragmentation by coupling Voronoi diagram and discretized virtual internal bond

The rock fragmentation involves the inter-block and the intra-block fracture.A simulation method for rock fragmentation is developed by coupling Voronoi diagram(VD)and discretized virtual internal bond(DVIB).The DVIB is a lattice model that consists of bonds.The VD is used to generate the potential block structure in the DVIB mesh.Each potential block may contain any number of bond cells.To characterize the inter-block fracture,a hyperelastic bond potential is employed for the bond cells that are cut by the VD edges.While to characterize the intra-block fracture,an elastobrittle bond potential is adopted for the bonds in a block.By this method,both the inter-block and intra-block fracture can be well simulated.The simulation results suggest that this method is a simple and efficient approach to rock fragmentation simulation with block smash.

Mycobacterium tuberculosis bacteremia in a human immunodeficiency virus-negative patient with liver cirrhosis:A case report

BACKGROUND With the increasing prevalence of human immunodeficiency virus(HIV),the incidence of Mycobacterium tuberculosis(M.tuberculosis)bacteremia has also increased.As a common affliction of acquired immunodeficiency syndrome patients,M.tuberculosis infection is associated in these patients with severe sepsis and high mortality.In contrast,M.tuberculosis bacteremia is rarely seen in HIVnegative patients,and M.tuberculosis has never been reported from the blood of patients with liver cirrhosis.CASE SUMMARY We evaluated a 55-year-old Chinese male patient who had been admitted to the hospital with abdominal distension of unknown cause of one-week duration,accompanied by diarrhea,shortness of breath,and occasional fever.Based on these indicators of abnormal inflammation and fever,we suspected the presence of an infection.Although evidence of microbial infection was not found in routine clinical tests and the patient did not show typical clinical symptoms of infection with M.tuberculosis,next-generation sequencing of blood samples nevertheless demonstrated the presence of M.tuberculosis,which was subsequently isolated from blood samples grown in conventional Bac T/ALERT FA blood culture bottles.CONCLUSION Our findings demonstrate that HIV-negative liver cirrhosis patients can also be infected with M.tuberculosis.

Comparison of efficacy of two different silicone hydrogel bandage contact lenses after T-PRK

AIM:To compare the efficacy between two different silicone hydrogel bandage contact lenses after transepithelial photorefractive keratectomy(T-PRK).METHODS:In this randomized controlled trial,a total of 89 patients(178 eyes) who underwent T-PRK at the Qingdao Eye Hospital from October to December 2019 were selected.One random eye wore a Senofilcon A bandage contact lens after surgery,and the other eye a Balafilcon A bandage contact lens.Pain scores,uncorrected visual acuity(UCVA),spherical equivalent(SE),corneal epithelial healing status,epithelial thickness,bandage lenses deposits,lenses movement,and ocular surface conditions were measured and compared.RESULTS:There were no differences between the two groups in UCVA,SE,corneal epithelial healing status,corneal epithelial thickness,tear river heights and tear film rupture time at each follow-up visit.However,postoperative pain scores in the Senofilcon A group were significantly lower than those of the Balafilcon A group(F_(intergroups)=67.833,P<0.001;F_(time)=383.773,P<0.001;F_(interaction)=57.344,P<0.001).The duration of pain in eyes in the Senofilcon A group was shorter than that of the Balafilcon A group(t=-3.326,P=0.001).The surface deposition scores and movement scores of Senofilcon A bandage lenses on the first and fourth days after surgery were lower than those of Balafilcon A bandage lenses(Z=-5.385,-6.782,P<0.001;Z=-8.336,-8.906,P<0.001).CONCLUSION:Both Senofilcon A and Balafilcon A bandage lenses have good efficacy after T-PRK.Senofilcon A lenses are associated with less pain and more comfort compared to Balafilcon A.

Genome Analysis of the Ancient Tracheophyte Selaginella tama#scina Reveals Evolutionary Features Relevant to the Acquisition of Desiccation Tolerance

Resurrection plants, which are the ＂gifts＂ of natural evolution, are ideal models for studying the genetic basis of plant desiccation tolerance. Here, we report a high-quality genome assembly of 301 Mb for the diploid spike moss Selaginella tamariscina, a primitive vascular resurrection plant. We predicated 27 761 protein-coding genes from the assembled S. tarnariscina genome, 11.38% （2363） of which showed signifi- cant expression changes in response to desiccation. Approximately 60.58% of the S. tamariscina genome was annotated as repetitive DNA, which is an almost 2-fold increase of that in the genome of desiccation- sensitive Selaginella moellendorffii. Genomic and transcriptomic analyses highlight the unique evolution and complex regulations of the desiccation response in S. tamariscina, including species-specific expan- sion of the oleosin and pentatricopeptide repeat gene families, unique genes and pathways for reactive oxygen species generation and scavenging, and enhanced abscisic acid （ABA） biosynthesis and potentially distinct regulation of ABA signaling and response. Comparative analysis of chloroplast genomes of several Selaginella species revealed a unique structural rearrangement and the complete loss of chloroplast NAD（P） H dehydrogenase （NDH） genes in S. tamariscina, suggesting a link between the absence of the NDH com- plex and desiccation tolerance. Taken together, our comparative genomic and transcriptomic analyses reveal common and species-specific desiccation tolerance strategies in S. tamariscina, providing signifi- cant insights into the desiccation tolerance mechanism and the evolution of resurrection plants.

Operational optimization of a building-level integrated energy system considering additional potential benefits of energy storage

As a key component of an integrated energy system(IES),energy storage can effectively alleviate the problem of the times between energy production and consumption.Exploiting the benefits of energy storage can improve the competitiveness of multi-energy systems.This paper proposes a method for day-ahead operation optimization of a building-level integrated energy system(BIES)considering additional potential benefits of energy storage.Based on the characteristics of peak-shaving and valley-filling of energy storage,and further consideration of the changes in the system’s load and real-time electricity price,a model of additional potential benefits of energy storage is developed.Aiming at the lowest total operating cost,a bi-level optimal operational model for day-ahead operation of BIES is developed.A case analysis of different dispatch strategies verifies that the addition of the proposed battery scheduling strategy improves economic operation.The results demonstrate that the model can exploit energy storage’s potential,further optimize the power output of BIES and reduce the economic cost.

Two-dimensional tungstate nanosheets for constructing novel photochromic hydrogel with ultrahigh flexibility

A hydrogel possessing interesting photochromic behaviors was developed by in situ ultraviolet(UV)irradiation-assisted polymerization of an aqueous solution of N-isopropylacrylamide monomer in the presence of cesium tungstate nanosheets.By this process,a hierarchical porous network structure was finely constructed while showing ultrahigh flexibility.More importantly,the newly prepared hydrogel retained the photochromic properties of the cesium tungstate nanosheets.The color transitions could be readily controlled by UV laser irradiation and were completely reversible via laser exposure or dark treatment.The nanocomposite hydrogel with its excellent photochromic properties and ultrahigh flexibility will have great applications in flexible photochromic devices.The synthetic procedure is simple and has promises to be extended to developing other hydrogels with various new functionalities.

Parasitic relationship of Cistanche deserticola and host-plant Haloxylon ammodendron based on genetic variation of host

Objective: Cistanche deserticola is a famous and endangered medicinal plant that is parasitic upon Haloxylon ammodendron with rather low parasitic rates. It is important to find high affinity germplasms for increasing the survival of C. deserticola. However, little is known in genetic variation and high affinity populations of H. ammodendron in China.Methods: In this study, 98 accessions of H. ammodendron seeds were collected from five regions covering almost the entire natural distribution of H. ammodendron in China. Their genetic variations were analyzed using AFLP and ITS by the maximum parsimony method, and a dendrogram was constructed using the unweighted pair-group method with arithmetic average(UPGMA). The parasitic rates of C. deserticola on different accessions of H. ammodendron were calculated in the field experiment.Results: Both AFLP and ITS methods consistently revealed that there was a high level of genetic diversity in the natural populations of H. ammodendron. Hierarchical population structure analysis uncovered a clear pattern that all populations were grouped into three main clusters, and eight populations from eastern region were genetically clustered together. These regions were significantly differentiated(P < 0.05), 13.10% of variation occurred among populations, and 86.90% within populations was revealed by analysis of molecular variance(AMOVA). The populations of Inner Mongolia had the highest parasitic rates followed by Ganjiahu Reserve and Yongning Plantation for the top three, which were not completely related to the genetic variation.Conclusion: Genetic characteristics of H. ammodendron in China were clarified and the order of affinity of different populations was given, which were primers for discovering high affinity germplasms.

Silk Fibroin Based Conductive Film for Multifunctional Sensing and Energy Harvesting

Development of biomaterial based flexible electronics has got intensive attention owing to the potential applications in the wearable and epidermal devices.Silk fibroin,as a natural textile material with excellent performance,has been widely concerned by industry and academy.However,the property of electrical insulation limits his development in the field of flexible electronics.In this paper,a regenerated silk fibroin/carbon nanotube(RSF/CNT)conductive film has been successfully fabricated and applied in flexible capacitive-type pressure sensor and wearable triboelectric nanogenerator by a facile method.The electrical conductivity and mechanical property of RSF/CNT film was optimized by investigating with different composite ratio from 10 to 90%(W_(RSF)/W_(CNT)).The RSF/CNT film has a good photothermal response and electric heating performance.We furtherly demonstrated that the RSF/CNT based sensor can be used as epidermal self-powered sensor for multifunction human motion monitoring and Morse code compilation.The observed research results have shown that the RSF/CNT film has a wide range of potential application prospects in the wearable electronics field.

Parallel isolation of calicivirus and reovirus from lethal co-infected mink during a potential epidemic of farmed mink infections

Mink has been identified as an animal with susceptibility to SARS-CoV-2 and also as the only animal with evidence to transmit the virus back to humans.Thus,the surveillance of viruses among high-density farmed minks has a significant meaning for the control of zoonotic emerging diseases in humans.Within anal swabs of minks that died of unknown causes in a mink farm,mink calicivirus(MCV)and mammalian orthoreovirus(MRV)were detected and simultaneously observed within MDCK cell culture from the sample of the same lethal mink.The parallel isolation was successfully performed by utilizing cell lines from different host sources with distinct viral sensitivities,i.e.Mv.1.Lu and Vero-E6 and the two viruses were independently separated.The prevalence of the virus among the minks and its genomic characteristics were investigated through deep sequencing technology.Phylogenetic analysis of the viral genome showed a close relationship of the newly isolated MCV-GCCDC8-2020 with MCV strains belonging to the genus Vesivirus,but with unique mutations derived from the major structural protein(VP1).The reovirus MRV-GCCDC9-2020 isolated from the same mink belongs to serotype 3 mammalian orthoreovirus and genome analysis showed a potential reassortment derived from reoviruses in different species.This study provides a beneficial reference on viral co-infection within disease investigation in farmed minks and raises the concern for the virus surveillance among the high-density fed animal farms.

一种柔性导电银胶的研发

导电银胶是柔性薄膜电子器件的重要基础材料,而高性能、低成本导电介质—低维银片及其制造技术是一项重要研究课题.本文发展了一种低成本、环保、且适合卷对卷制备的低维导电银片的制作方法.该方法制备的微纳银片,形貌尺寸可控(直径:20200μm;厚度20300 nm)、性能优异.进而,基于聚氨酯基底,制备了柔性、无助剂的导电银胶.该导电银胶渗流阈值远低于采用其他银颗粒填料所制备的银胶.当银片添加量仅为13.7 wt%时,导电银片能有效形成导电网络,其电导率高达5240 S/cm,显著优于同类导电银胶;而且,当拉伸比例为40%时,电导率未见明显变化.所制备超薄银片的大比表面积、光滑表面使其形成有效的错位堆积,构建有效电子通路,从而赋予导电银胶的高电导、高柔性.

The electric field effect on the sensitivity of tin oxide gas sensors on nanostructured substrates at low temperature

A novel low-temperature SnO_(2) gas sensor was prepared and studied on silicon nanostructures formed by femtosecond laser irradiation.By applying a bias voltage on the silicon substrate to alter the charge distribution on the surface of the SnO_(2),carbon monoxide(CO),and ammonia(NH_(3))gas can be distinguished by the same sensor at room temperature.The experimental results are explained with a mechanism that the sensor works at low temperature because of adsorption of gas molecules that trap electrons to the surface of the SnO_(2).

Effect of Bushen Qingre Yuyin Decoction on Salivary Secretion, Spleen Index, Submandibular Gland Index, Submandibular Gland Histomorphology, and aqp5 Expression in the Nonobese Diabetic Mouse Model

Objective:The objective of this study was to observe the effect of Bushen Qingre Yuyin Decoction on the spleen index,submandibular gland index,salivary secretion,submandibular gland morphology,and aquaporin 5(AQP5)expression levels in the submandibular gland.Materials and Methods:Fifty 8-week-old nonobese diabetic(NOD)female mice were randomly divided into the following five groups:model;hydroxychloroquine;and high-,medium-,and low-dose Bushen Qingre Yuyin Decoction prescription.The blank group consisted of ten 8-week-old Balb/C rats.Bushen Yuyin Qingre Decoction was administered by gavage at 20,40,and 80 g/kg in the low-,medium-,and high-dose groups,respectively.The hydroxychloroquine group was administered hydroxychloroquine at a dose of 80 mg/kg by gavage.The normal and model groups were administered the same amount of saline.After the different administrations,the amount of salivary secretion in the mice was regularly observed.After 12 weeks,the mice were sacrificed,and their submandibular gland tissues were excised,stained with hematoxylin-eosin,and pathologically scored.AQP5 expression levels in the tissues were detected using real-time polymerase chain reaction.Results:The spleen index of mice in the high-dose group was higher than that in the model group(P<0.05),and the submandibular gland index of the hydroxychloroquine group and all the Bushen Qingre Yuyin Decoction prescription groups was higher than that in the model group(P<0.05).After 6 weeks,the salivary volume of the hydroxychloroquine group and all the Bushen Qingre Yuyin Decoction prescription groups was significantly higher than that of the model group(P<0.05);the amount of lymphocyte infiltration in mice among each administration group was significantly reduced(P<0.05);and the AQP5 expression levels in the submandibular glands of mice had significantly increased in the hydroxychloroquine and high-dose groups(P<0.05),with the high-dose group showing the best effect.Conclusion:Bushen Qingre Yuyin Decoction can effectively increase the spleen and submandibular gland indexes of NOD mice,increase the amount of salivary secretion,reduce lymphocyte infiltration in submandibular gland tissue,and significantly increase AQP5 expression levels,which may be positively correlated with the administered dose.

A Review of the Index Method in Closed Geodesic Problem

In this paper we review and systematize the index method in closed geodesic problem.As we know,the closed geodesic problem on compact Riemannian or Finsler manifold is a famous problem,and has far from been resolved.In recent years,the Maslov-type index theory for symplectic path has been applied to studying the closed geodesic problem,and has induced a great number of results on the multiplicity and stability of closed geodesics.We will systematically introduce these progresses in this review.