Development of a stable attenuated double-mutant of tobacco mosaic virus for cross-protection

Tobacco(Nicotiana tabacum)and tomato(Solanum lycopersicum)are two major economic crops in China.Tobacco mosaic virus(TMV;genus Tobamovirus)is the most prevalent virus infecting both crops.Currently,some widely cultivated tobacco and tomato cultivars are susceptible to TMV and there is no effective strategy to control this virus.Cross-protection can be a safe and environmentally friendly strategy to prevent viral diseases.However,stable attenuated TMV mutants are scarce.In this study,we found that the substitutions in the replicase p126,arginine at position 196(R^(196))with aspartic acid(D),glutamic acid at position 614(E^(614))with glycine(G),serine at position 643(S^(643))with phenylalanine(F),or D at position 730(D^(730))with S,significantly reduced the virulence and replication of TMV.However,only the mutation of S^(643) to F reduced the RNA silencing suppression activity of TMV p126.A double-mutant TMV-E614G-S643F induced no visible symptom and was genetically stable through six successive passages in tobacco plants.Furthermore,our results showed that TMV-E614G-S643F double-mutant could provide effective protection against the wild-type TMV infection in tobacco and tomato plants.This study reports a promising mild mutant for cross-protection to control TMV in tobacco and tomato plants.

翱翔小镇——高新技术产业为核心的创新小镇

针对新型城镇化背景下特色小镇建设的问题,分析西安市西咸新区翱翔小镇的规划设计,提出以高新技术产业为核心,实现产学研用高度融合,坚持TOD规划理念,强调功能混合复合的设计理念。本文对翱翔小镇在科学定位、明确布局、功能融合、特色塑造等方面进行了积极探索,其设计理念和实践经验可为其他城市的特色小镇建设提供借鉴。

Factors affecting genomic selection revealed by empirical evidence in maize

Genomic selection(GS) as a promising molecular breeding strategy has been widely implemented and evaluated for plant breeding, because it has remarkable superiority in enhancing genetic gain, reducing breeding time and expenditure, and accelerating the breeding process. In this study the factors affecting prediction accuracy(rMG) in GS were evaluated systematically, using six agronomic traits(plant height, ear height, ear length, ear diameter,grain yield per plant and hundred-kernel weight) evaluated in one natural and two biparental populations. The factors examined included marker density, population size, heritability,statistical model, population relationships and the ratio of population size between the training and testing sets, the last being revealed by resampling individuals in different proportions from a population. Prediction accuracy continuously increased as marker density and population size increased and was positively correlated with heritability; rMGshowed a slight gain when the training set increased to three times as large as the testing set. Low predictive performance between unrelated populations could be attributed to different allele frequencies, and predictive ability and prediction accuracy could be improved by including more related lines in the training population. Among the seven statistical models examined, including ridge regression best linear unbiased prediction(RR-BLUP), genomic BLUP(GBLUP), Bayes A, Bayes B, Bayes C, Bayesian least absolute shrinkage and selection operator(Bayesian LASSO), and reproducing kernel Hilbert space(RKHS), the RKHS and additive-dominance model(Add + Dom model) showed credible ability for capturing non-additive effects, particularly for complex traits with low heritability. Empirical evidence generated in this study for GS-relevant factors will help plant breeders to develop GS-assisted breeding strategies for more efficient development of varieties.

Favorable haplotypes and associated genes for flowering time and photoperiod sensitivity identified by comparative selective signature analysis and GWAS in temperate and tropical maize

On the basis of growing environment,maize can largely be classified into temperate and tropical groups,leaving extensive genetic variation and evolutionary signatures in the maize genome.To identify candidate genes governing flowering time and photoperiod sensitivity,selective signature analysis and SNP-and haplotype-based GWAS were performed using 39,350 high-quality SNP markers in temperate and tropical maize groups consisting of 410 inbred lines phenotyped in three representative experiments in different latitudes.Selective signature analysis revealed 106 selective-sweep regions containing 423 candidate genes involved mainly in biological regulation and biosynthesis pathways.Among these genes,25 overlapped with known genes governing flowering time and photoperiod sensitivity and 37 were also detected by GWAS for days to tassel,anthesis-silk interval,and photoperiod sensitivity measured by days to silking.Only two of the candidate genes governing flowering time overlapped selective signals.Most haplotype alleles within significant haplotype loci showed the same direction of effect on flowering time and photoperiod sensitivity.The inbred lines carrying GATT at HapL499(haplotype locus 499)on chromosome 1 had relatively short flowering times.Lines carrying CA at HapL4054 on chromosome 10,TA at HapL4055 on chromosome 10,and GTTGT at HapL978 on chromosome 2 were less sensitive to photoperiod than lines carrying other haplotype alleles.Haplotype loci associated with flowering time and photoperiod sensitivity explained respectively 17.5%–18.6%and 11.2%–15.5%of phenotypic variation.Candidate genes and favorable haplotypes identified in this study may support the more efficient utilization of maize germplasm groups.

Role of F-18 FDG PET/CT imaging in the diagnosis of paraneoplastic neurological syndromes

Paraneoplastic neurological syndromes(PNS) is a series of rare neurologic disorders which happen with an underlying malignancy. It has various clinical symptoms proceding to the diagnosis of tumors. Although the abnormality of anti-neuronal antibodies is suggestive of PNS and tumors, there exist many false positive and false negative cases. The diagnosis of PNS is usually a challenge in clinic. Positron emission tomography/computed tomography(PET/CT) imaging is an anatomical and functional fusion imaging method, which provides the whole-body information by single scan. Fluorodeoxyglucose(FDG) PET/CT imaging can not only detect potential malignant lesions in the whole body, but also assess functional abnormality in the brain. In this review, the mechanism, clinical manifestation, diagnostic procedure and the recent progress of the utility of FDG PET/CT in PNS are introduced respectively.

Analysis of Relay Deployment Based on Handover Outage Probability in High Speed Scenarios

The LTE and LTE-Advanced systems are supposed to be the most popular cellular network in 4Gnetworks. Relay technology is one of the most preferred technologies proposed in LTE-Advanced standardization to improve the capacity and coverage. This paper analyses the handover outage probability through relay deployment, and proposes some proofs and suggestions for relay deployment to minimize the handover outage probability in high speed scenarios.

Scientific objectives of the Hot Universe Baryon Surveyor(HUBS) mission

The Hot Universe Baryon Surveyor(HUBS) is a proposed space-based X-ray telescope for detecting X-ray emissions from the hot gas content in our universe. With its unprecedented spatially-resolved high-resolution spectroscopy and large field of view,the HUBS mission will be uniquely qualified to measure the physical and chemical properties of the hot gas in the interstellar medium, the circumgalactic medium, the intergalactic medium, and the intracluster medium. These measurements will be valuable for two key scientific goals of HUBS, namely to unravel the AGN and stellar feedback physics that governs the formation and evolution of galaxies, and to probe the baryon budget and multi-phase states from galactic to cosmological scales. In addition to these two goals, the HUBS mission will also help us solve some problems in the fields of galaxy clusters, AGNs, difuse X-ray backgrounds, supernova remnants, and compact objects. This paper discusses the perspective of advancing these fields using the HUBS telescope.

Piezoluminescent devices by designing array structures

Mechanoluminescence has attracted increasing attentions because it can convert the kinetic energy during human daily motions into light to be used in sensors and displays. However, its practical applications are still hindered by the weak brightness and limited color while under large forces. Herein, we developed novel piezoluminescent devices(PLDs) which could effectively emit visible light under low pressing forces through the stress-concentration and enhancing deformation on the basis of carefully-designed array structures. The emitting colors were also tunable by using bilayer luminescent film under different pressures. This work not only provides a new strategy to effectively harvest mechanical energy into light,but also presents a scalable, low-cost and color-tunable PLD which shows great potentials in various applications such as luminescent floors, shoes and stress-activated displays.

Metabolism and immunity in breast cancer

Breast cancer is one of the most common malignancies that seriously threaten women’s health.In the process of the malignant transformation of breast cancer,metabolic reprogramming and immune evasion represent the two main fascinating characteristics of cancer and facilitate cancer cell proliferation.Breast cancer cells generate energy through increased glucose metabolism.Lipid metabolism contributes to biological signal pathways and forms cell membranes except energy generation.Amino acids act as basic protein units and metabolic regulators in supporting cell growth.For tumor-associated immunity,poor immunogenicity and heightened immunosuppression cause breast cancer cells to evade the host’s immune system.For the past few years,the complex mechanisms of metabolic reprogramming and immune evasion are deeply investigated,and the genes involved in these processes are used as clinical therapeutic targets for breast cancer.Here,we review the recent findings related to abnormal metabolism and immune characteristics,regulatory mechanisms,their links,and relevant therapeutic strategies.

Tunable self-powered n-SrTiO3 photodetectors based on varying CuS-ZnS nanocomposite film (p-CuZnS, p-CuS, and n-ZnS)

The heterojunction photodetector between n-SrTiO3(n-STO)and p-CuS-ZnS(p-CZS)is prepared by a simple chemical bath deposition.The p-CZS/n-STO photodetector exhibits excellent self-powered characteristics under 390-nm light illumination,including high photosensitivity(on/off ratio of 300),fast response speed(0.7/94.6 ms),and good wavelength selectivity(410-380 nm).More importantly,the self-powered n-STO photodetectors can be regulated by varying the composition of CZS film(p-CZS,p-CuS,and n-ZnS).All devices exhibit a large opencircuit voltage and show different self-powered behaviors because of the different built-in electric fields.The open-circuit voltages of the CZS/STO,CuS/STO,and ZnS/STO devices are measured to be 0.56,0.30,and 0.35 V,respectively.This work provides a simple and effective way to fabricate tunable self-powered photodetectors by varying the composition of the nanocomposite film.

Membrane-camouflaged supramolecular nanoparticles for co-delivery of chemotherapeutic and molecular-targeted drugs with siRNA against patient-derived pancreatic carcinoma

Pancreatic cancer remains one of the most lethal malignancies worldwide. The combination of the first-line standard agent gemcitabine(GEM) with the molecular-targeted drug erlotinib(Er) has emerged as a promising strategy for pancreatic cancer treatment. However, the clinical benefit from this combination is still far from satisfactory due to the unfavorable drug antagonism and the fibrotic tumor microenvironment. Herein, we propose a membrane-camouflaged dual stimuliresponsive delivery system for the co-delivery of GEM and Er into pancreatic cancer cells and tissues to block the antagonism, as well as reshapes profibrotic tumor microenvironment via simultaneous delivery of small interference RNA(siRNA) for synergistic pancreatic cancer treatment. This “all-in-one”delivery system exhibits sensitive GSH and pH-dependent drug release profiles and enhances the inhibitory effects on the proliferation and migration of tumor cells in vitro. Excitingly, the systemic injection of such a biomimetic drug co-delivery system not only resulted in superior inhibitory effects against orthotopic pancreatic tumor and patient-derived tumor(PDX), but also greatly extended the survival rate of tumor-bearing mice. Our findings provide a promising therapeutic strategy against pancreatic cancer through the enhanced synergistic effect of target therapy, chemotherapy and anti-fibrotic therapy, which represents an appealing way for pancreatic cancer treatment.

Experimental investigation and feasibility analysis of a thermophotovoltaic cogeneration system in high-temperature production processes

The experimental I- Vcharactefistics ofa Si cell module in a thermophotovoltaic （TPV） system were investigated using SiC or Yb203 radiator. The results demonstrate that the short-circuit current increases while the open-circuit voltage, along with the fill factor, decreases with the cell temperature when the radiator temperature increases from 1273 to 1573 K, leading to a suppressed increase of the output power of the system. The maximum output power density of the cell module is 0.05 W/cm2 when the temperature of the SiC radiator is 1573 K, while the electrical efficiency of the system is only 0.22%. The efficiency is 1.3% with a Yb203 radiator at the same temperature, however, the maximum output power density drops to 0.03 W/cm2. The values of the open-circuit voltage and the maximum output power obtained from the theoretical model conform to the experimental ones. But the theoretical short-circuit current is higher because of the existence of the contact resistance inside the cell module. In addition, the performance and cost of TPV cogeneration systems with the SiC or Yb203 radiator using industrial high-temperature waste heat were analyzed. The system electrical efficiency could reach 3.1% with a Yb203 radiator at 1573K. The system cost and investment recovery period are 6732 EUR/kWel and 14 years, respectively.

A dual-specific CRISPR-Cas nanosystem for precision therapeutic editing of liver disorders

Dear Editor,The most common liver disorders,such as acute liver injury and liver fbrosis,can induce acute or chronic inflammatory responses,which in turn gradually promote the development and progres-sion of the disorder.

Research on the efficiency of Clean Energy use in four States of the United States

Energy is a serious problem in today's world, which is closely related to the sustainable development of all mankind and to the fundamental interests of each country. Today, the world still operates on the basis of three traditional fossil fuels, coal, oil and natural gas, but faced with the scarcity,non-renewable, strong political color and the devastating blow caused by the depletion of fossil fuels, human beings have begun to realize the necessity and urgency of developing alternative energy sources since last century.