Revealing the potential of apparent critical current density of Li/garnet interface with capacity perturbation strategy

Apparent critical current density(j_(Ac)^(a))of garnet all-solid-state lithium metal symmetric cells(ASSLSCs)is a fundamental parameter for designing all-solid-state lithium metal batteries.Nevertheless,how much the possible maximum apparent current density that a given ASSLSC system can endure and how to reveal this potential still require study.Herein,a capacity perturbation strategy aiming to better measure the possible maximum j_(Ac)^(a)is proposed for the first time.With garnet-based plane-surface structure ASSLSCs as an exemplification,the j_(Ac)^(a)is quite small when the capacity is dramatically large.Under a perturbed capacity of 0.001 mA h cm^(-2),the j_(Ac)^(a)is determined to be as high as 2.35 mA cm^(-2)at room temperature.This investigation demonstrates that the capacity perturbation strategy is a feasible strategy for measuring the possible maximum j_(Ac)^(a)of Li/solid electrolyte interface,and hopefully provides good references to explore the critical current density of other types of electrochemical systems.

Genetic characterization and linkage disequilibrium mapping of resistance to gray leaf spot in maize(Zea mays L.)

Gray leaf spot(GLS),caused by Cercospora zeae-maydis,is an important foliar disease of maize(Zea mays L.)worldwide,resistance to which is controlled by multiple quantitative trait loci(QTL).To gain insights into the genetic architecture underlying the resistance to this disease,an association mapping population consisting of 161 inbred lines was evaluated for resistance to GLS in a plant pathology nursery at Shenyang in 2010 and 2011.Subsequently,a genome-wide association study,using 41,101 single-nucleotide polymorphisms(SNPs),identified 51 SNPs significantly(P<0.001)associated with GLS resistance,which could be converted into 31 QTL.In addition,three candidate genes related to plant defense were identified,including nucleotidebinding-site/leucine-rich repeat,receptor-like kinase genes similar to those involved in basal defense.Two genic SNPs,PZE-103142893 and PZE-109119001,associated with GLS resistance in chromosome bins 3.07 and 9.07,can be used for marker-assisted selection(MAS)of GLS resistance.These results provide an important resource for developing molecular markers closely linked with the target trait,enhancing breeding efficiency.

Evaluation of maize inbred lines currently used in Chinese breeding programs for resistance to six foliar diseases

Foliar diseases are common in most maize-producing regions and have caused serious yield reduction in China. To evaluate genetic resistance of parental lines actively used in maize breeding programs to major foliar diseases, 152 maize inbred lines were tested against northern corn leaf blight(NCLB), southern corn leaf blight(SCLB), Curvularia leaf spot(CLS),gray leaf spot(GLS), common rust, and southern rust from 2003 to 2005. A small number of lines exhibited highly resistant reactions to common rust and southern rust, but none were highly resistant to NCLB, SCLB, CLS, and GLS. Although 53.3%, 40.8%, and 80.7% of lines were resistant to NCLB, SCLB, and common rust, the resistance in most lines was moderate.Resistance to CLS, GLS, and southern rust was rare in this collection of maize lines. Five lines,313, Chang 7-2, Qi 319, Qi 318, and Shen 137, were resistant to five diseases tested. Lines belonging to heterotic subgroup PB exhibited better resistance to the foliar diseases than lines from other heterotic subgroups, such as BSSS, PA, Lancaster, LRC, and PA. The results will be of benefit to breeders for selecting lines in disease resistance breeding programs.

Cooperation of nitrogen-doping and catalysis to improve the Li-ion storage performance of lignin-based hard carbon

Hard carbon draws great interests as anode material in lithium ion batteries （LIBs） due to its high the- oretical capacity, high rate capability and abundance of its precursors. Herein we firstly synthesize the lignin-melamine resins by grafting melamine onto lignin. Afterwards, nitrogen doped hard carbon is pre- pared by the pyrolysis of lignin-melamine resins with the aid of catalyst （Ni（NO_3）2·6H_2O） at 1000 ℃. Compared with the samples without nitrogen-doping and catalysis, as-prepared nitrogen doped hard car- bon exhibits higher reversible capacity （345 mAh g-1 at 0.1 A g-1 ）, higher rate capability （145 mAh g-1 at 5 A g-1） and excellent cycling stability. The superior electrochemical performance is ascribed to the synergistic effect of nitrogen doping, graphitic structure and amorphous structure. Among them, nitro- gen doping could create the vacancies around the nitrogen sites, which enhance the reactivity and the electronic conductivity of materials. Additionally, graphitic structure also enhances the electronic con- ductivity of materials, thus improving the electrochemical performance of hard carbon. It is worthwhile that Iignin, renewable and abundant biopolymer, is converted to hard carbon with good electrochemical performance, which realizes the high value utilization of lignin.

Incorporating multifunctional LiAlSiO_(4) into polyethylene oxide for high-performance solid-state lithium batteries

High ionic conductivity,good electrochemical stability,and satisfactory mechanical property are the crucial factors for polymer solid state electrolytes.Herein,fast ion conductor LiAlSiO_4(LASO) is incorporated into polyethylene oxide(PEO)-based solid-state electrolytes(SSEs).The SSEs containing LASO exhibit enhanced mechanical properties performance compared to pristine PEO-LiTFSI electrolyte.A reduced melting transition temperature of 40.57℃ is enabled by introducing LASO in to PEO-based SSE,which is beneficial to the motion of PEO chain and makes it possible for working at a moderate environment.Coupling with the enhanced motion of PEO,dissociation of the lithium salt,and conducting channel of LASO,the optimized composite polymer SSE exhibits a high ionic conductivity of 4.68×10^(-4),3.16×10^(-4) and 1.62×10^(-4) S cm^(-1) at 60,50 and 40℃,respectively.The corresponding LiFePO_4//Li solid-state battery exhibits high specific capacities of 166,160 and 139 mAh g^(-1) at 0.2 C under 60,40 and 25℃.In addition,it remains 130 mAh g^(-1) at 4.0 C,and maintains 91.74% after 500 cycles at 1.0 C under 60℃.This study provides a simple approach for developing ionic conductor-filled polymer electrolytes in solid-state lithium battery application.

Bifunctional Li6CoO4 serving as prelithiation reagent and pseudocapacitive electrode for lithium ion capacitors

Lithium ion capacitors(LICs)have been widely used as energy storage devices due to their high energy density and high power density.For LICs,pre-lithiation of negative electrode is necessary.In this work,we employ a bifunctional Li6CoO4(LCO)as cathodic pre-lithiation reagent to improve the electrochemical performance of LICs.The synthesized LCO exhibited high first charge specific capacity of 721 mAh g-1and extremely low initial coulombic efficiency of 3.19%,providing sufficient Li+ for the pre-lithiation of negative electrode in the first charge.Simultaneously,Li6–xCoOy is generated from LCO during the first charge process,which exhibits pseudocapacitive property and contributes to capacity in form of surface capacitance during subsequent cycles,increasing the capacity of capacitive positive electrode.With the appropriate amounts of addition to the positive side in LICs,this bifunctional prelithiation reagent LCO shows significantly improved the electrochemical performance with the energy density of 78.5 Wh kg-1after 300 cycles between 2.0 and 4.2 V at 250 mA g-1.

Evolution of the morphology,structural and thermal stability of LiCoO_(2) during overcharge

The overcharge behaviors of 1000 m Ah LiCoO_(2)/graphite pouch cells are systematically investigated through the analysis of morphology,structural and thermal stability of LiCoO_(2) under different state of charge(SOC)of 120%,150%,174%,190%and 220%.The LiCoO_(2) experiences the phase transition from O3 to H1-3 and then O1 together with the grain breakage and boundary slip as evidenced by XRD and SEM analysis respectively,which results in the pronounced Co dissolution after the SOC of 174%.The impedance analysis of the pouch cells and coin cells demonstrates that the main contribution of impedance increase originates from the LiCoO_(2) electrode.Under the combined effect of structural collapse,Co dissolution,and electrolyte oxidization,the thermal stability of Li CoO_(2) cathode materials reduces with the progressing of overcharge as revealed by differential scanning calorimetry(DSC)results.We hope that this comprehensive understanding can provide meaningful guidance for advancing the overcharge performance of LiCoO_(2)/graphite pouch cells.

Spray pyrolysis synthesis of nickel-rich layered cathodes LiNi_(1-2x)Co_xMn_xO_2(x = 0.075, 0.05, 0.025) for lithium-ion batteries

In this study we report a series of nickel-rich layered cathodes LiNi1-2xCoxMnxO2（x = 0.075, 0.05,0.025） prepared from chlorides solution via ultrasonic spray pyrolysis. SEM images illustrate that the samples are submicron-sized particles and the particle sizes increase with the increase of Ni content.LiNi0.85Co0.075Mn0.075O2 delivers a discharge capacity of 174.9 mAh g-1 with holding 93% reversible capacity at 1 C after 80 cycles, and can maintain a discharge capacity of 175.3 mAh g-1 at 5 C rate. With increasing Ni content, the initial specific capacity increases while the cycling and rate performance degrades in some extent. These satisfying results demonstrate that spray pyrolysis is a powerful and efficient synthesis technology for producing Ni-rich layered cathode（Ni content 〉 80%）.

Free-standing ultrathick LiMn_(2)O_(4)@single-wall carbon nanotubes electrode with high areal capacity

The ever-increasing demands for advanced lithium-ion batteries with high energy density have greatly stimulated the pursuit of thick electrodes with high active material loading.However,it is not feasible to prepare thick electrodes with traditional coating methods due to mechanical instability.Herein,using single-wall carbon nanotubes(SWCNT)as conductive carbon and binder,free-standing LiMn_(2)O_(4) thick electrodes(F-LMO)with ultrahigh-mass loading up to~190 mg cm^(-2)were prepared by vacuum filtration combined with freeze-drying.The thick electrodes with~30 mg cm^(-2)mass loading achieved a high specific capacity of 106.7 mAh g^(-1)with a good capacity retention of 94%over 50 cycles at 0.5 C,which was superior to the traditional coating electrodes(~20 mg cm^(-2))of 99.3 mAh g^(-1)with 95%because of the enhanced electronic conductivity originated from SWCNT.In addition,the high active material ratio of 97.5 wt%,near-theoretical reversible capacity,and high mass loading gave ultrathick F-LMO electrodes(600μm)of~190 mg cm^(-2)with a remarkable areal capacity of 20 mAh cm^(-2).Moreover,the concentration polarization that occurred in the thick F-LMO electrodes under high current density was discussed via electrochemical stimulation.

A differentially methylated region of the ZmCCT10 promoter affects flowering time in hybrid maize

Flowering time(FT) is a key maize domestication trait, variation in which allows maize to grow in a wide range of latitudes. Although previous studies have investigated the genetic control of FT-related traits per se, few studies of FT hybrid performance have been published. We characterized the genomic architecture associated with hybrid performance for FT in a hybrid panel by testcrossing Chang 7–2 with 328Ye478 × Qi319 recombinant inbred lines(RILs). We identified 11 quantitative trait loci(QTL) for hybrid performance in FT-related traits, including a major QTL qFH10 that controls hybrid performance and heterosis in a summer maize-growing region. However, this locus acts in regulating FT traits per se only in a spring maize-growing region. We validated ZmCCT10 as a candidate gene for qFH10 and found that differences between hybrids and their parental lines in DNA methylation in the differentially methylated region(DMR, –700 to –1520) of the ZmCCT10 promoter affected gene expression pattern and thereby FT in the summer maize-growing region.

Genomic prediction of yield performance among single-cross maize hybrids using a partial diallel cross design

Genomic prediction(GP)in plant breeding has the potential to predict and identify the best-performing hybrids based on the genotypes of their parental lines.In a GP experiment,34 elite inbred lines were selected to make 285 single-cross hybrids in a partial-diallel cross design.These lines represented a mini-core collection of Chinese maize germplasm and comprised 18 inbred lines from the Stiff Stalk heterotic group and 16 inbred lines from the Non-Stiff Stalk heterotic group.The parents were genotyped by sequencing and the 285 hybrids were phenotyped for nine yield and yield-related traits at two locations in the summer sowing area(SUS)and three locations in the spring sowing area(SPS)in the main maizeproducing regions of China.Multiple GP models were employed to assess the accuracy of trait prediction in the hybrids.By ten-fold cross-validation,the prediction accuracies of yield performance of the hybrids estimated by the genomic best linear unbiased prediction(GBLUP)model in SUS and SPS were 0.51 and 0.46,respectively.The prediction accuracies of the remaining yield-related traits estimated with GBLUP ranged from 0.49 to 0.86 and from 0.53 to 0.89 in SUS and SPS,respectively.When additive,dominance,epistasis effects,genotype-by-environment interaction,and multi-trait effects were incorporated into the prediction model,the prediction accuracy of hybrid yield performance was improved.The ratio of training to testing population and size of training population optimal for yield prediction were determined.Multiple prediction models can improve prediction accuracy in hybrid breeding.

Boosting the performance of LiNi_(0.90)Co_(0.06)Mn_(0.04)O_(2) electrode by uniform Li_(3)PO_(4) coating via atomic layer deposition

Ultra-high nickel material is considered to be a promising cathode material.However,with the increase of nickel content,the interfacial side reactions between the cathode and electrolyte become increasingly serious.Herein,an atomically controllable ionic conductor Li_(3)PO_(4)(LPO)coating is deposited on the LiNi_(0.90)Co_(0.06)Mn_(0.04)O_(2)(NCM9064)based electrode by the atomic layer deposition method.The results shows that the LPO coating is uniformly and densely covered on the surface of secondary particles of NCM9064,helping to prevent the direct contact between the electrolyte and cathode during the chargingdischarging process.In addition,the coating layer is electrochemically stable.As a result,the interfacial side reactions during the long cycle are effectively suppressed,and the solid electrolyte interphase layer at the interface is stabilized.The electrode with 20 layers of LPO deposition(ALD-LPO-20)exhibits an excellent capacity retention of 81%after 200 cycles in 2.8-4.3 V at 25℃,which is 18%higher than the unmodified material(ALD-LPO-0).Besides,the moderate LPO coating improves the rate capability and high temperature cycling performance of NCM9064.This study provides a method for the modification of ultra-high nickel cathode materials and corresponding electrodes.

Zea mays(L.) P1 locus for cob glume color identified as a post-domestication selection target with an effect on temperate maize genomes

Artificial selection during domestication and post-domestication improvement results in loss of genetic diversity near target loci. However, the genetic locus associated with cob glume color and the nature of the genomic pattern surrounding it was elusive and the selection effect in that region was not clear. An association mapping panel consisting of 283 diverse modern temperate maize elite lines was genotyped by a chip containing over 55,000 evenly distributed SNPs. Ten-fold resequencing at the target region on 40 of the panel lines and 47 tropical lines was also undertaken. A genome-wide association study(GWAS) for cob glume color confirmed the P1 locus, which is located on the short arm of chromosome 1, with a-log10 P value for surrounding SNPs higher than the Bonferroni threshold(α/n, α < 0.001) when a mixed linear model(MLM) was implemented. A total of 26 markers were identified in a 0.78 Mb region surrounding the P1 locus, including 0.73 Mb and 0.05 Mb upstream and downstream of the P1 gene, respectively. A clear linkage disequilibrium(LD) block was found and LD decayed very rapidly with increasing physical distance surrounding the P1 locus. The estimates of π and Tajima's D were significantly(P < 0.001) lower at both ends compared to the locus. Upon comparison of temperate and tropical lines at much finer resolution by resequencing(180-fold finer than chip SNPs), a more structured LD block pattern was found among the 40 resequenced temperate lines. All evidence indicates that the P1 locus in temperate maize has not undergone neutral evolution but has been subjected to artificial selection during post-domestication selection or improvement. The information and analytical results generated in this study provide insights as to how breeding efforts have affected genome evolution in crop plants.

Creation of targeted inversion mutations in plants using an RNA-guided endonuclease

Inversions are DNA rearrangements that are essential for plant gene evolution and adaptation to environmental changes. We demonstrate the creation of targeted inversions and previously reported targeted deletion mutations via delivery of a pair of RNA-guided endonucleases(RGENs) of CRISPR/Cas9. The efficiencies of the targeted inversions were2.6% and 2.2% in the Arabidopsis FLOWERING TIME(At FT) and TERMINAL FLOWER 1(At TFL1)loci, respectively. Thus, we successfully established an approach that can potentially be used to introduce targeted DNA inversions of interest for functional studies and crop improvement.

RNA-seq analysis of unintended effects in transgenic wheat overexpressing the transcription factor GmDREB1

The engineering of plants with enhanced tolerance to abiotic stresses typically involves complex multigene networks and may therefore have a greater potential to introduce unintended effects than the genetic modification for simple monogenic traits. For this reason, it is essential to study the unintended effects in transgenic plants engineered for stress tolerance. We selected drought-and salt-tolerant transgenic wheat overexpressing the transcription factor, GmDREB1, to investigate unintended pleiotropic effects using RNA-seq analysis. We compared the transcriptome alteration of transgenic plants with that of wild-type plants subjected to salt stress as a control. We found that GmDREB1 overexpression had a minimal impact on gene expression under normal conditions.GmDREB1 overexpression resulted in transcriptional reprogramming of the salt response,but many of the genes with differential expression are known to mitigate salt stress and contribute incrementally to the enhanced stress tolerance of transgenic wheat. GmDREB1 overexpression did not activate unintended gene networks with respect to gene expression in the roots of transgenic wheat. This work is important for establishing a method of detecting unintended effects of genetic engineering and the safety of such traits with the development of marketable transgenic crops in the near future.

Mapping QTL for flowering time-related traits under three plant densities in maize

Flowering time is an indicator of adaptation in maize and a key trait for selection in breeding.The genetic basis of flowering time in maize,especially in response to plant density,remains unclear.The objective of this study was to identify maize quantitative trait loci(QTL)associated with flowering time-related traits that are stably expressed under several plant densities and show additive effects that vary with plant density.Three hundred recombinant inbred lines(RIL)derived from a cross between Ye 478 and Qi 319,together with their parents,were planted at three plant densities(90,000,120,000,and 150,000 plants ha^(-1))in four environments.The five traits investigated were days to tasseling(DTT),days to silking(DTS),days to pollen shed(DTP),interval between anthesis and silking(ASI),and interval between tasseling and anthesis(TAI).A high-resolution bin map was used for QTL mapping.In the RIL population,the DTT,DTS,and DTP values increased with plant density,whereas the ASI and TAI values showed negligible response to plant density.A total of 72 QTL were identified for flowering time-related traits,including 15 stably expressed across environments.Maize flowering time under different densities seems to be regulated by complex pathways rather than by several major genes or an independent pathway.The effects of some stable QTL,especially qDTT8-1 and qDTT10-4,varied with plant density.Fine mapping and cloning of these QTL will shed light on the mechanism of flowering time and assist in breeding earlymaturing maize inbred lines and hybrids.

Bird functional traits affect seed dispersal patterns of China's endangered trees across different disturbed habitats

Background: The most dominant global threat to natural forests and their biodiversity is land-cover change, which has negative impacts on both species persistence and ecosystem functions. Land-cover change could alter animal behaviour and disrupt seed dispersal mutualisms. However, its effects on the role of bird functional traits in seed dispersal are not well studied.Methods: In the present study, we assessed the contributions of bird functional traits(behavioural traits: food habit, foraging pattern, foraging frequency, and habitat specialisation; morphological traits: weight, body length, wing length, and tail length) to both seed removal patterns and seed dispersal distances of an endangered and native tree species, Chinese yew(Taxus chinensis), in farmland, patchy habitat, and natural habitat, of southeast China.Results: We found that the ability of T. chinensis trees to form seed dispersal mutualisms with local birds varied across the different disturbed habitats. As a consequence of these mutualisms, more seeds were removed by birds from the patchy habitat than from the other two habitats. The number of seeds removed increased with bird foraging frequency. Moreover, the dispersal distance from the three habitats differed, and the longest dispersal distances were observed at both the patchy habitat and the farmland site. Seed dispersal distance increased with bird tail and wing length.Conclusions: Our results highlight the importance of bird functional traits in the seed dispersal patterns of endangered trees across disturbed forest habitats, which should be considered for tree conservation and management.

SYNTHESIS AND CHARACTERIZATION OF HYDROXYLATED FULLERENE EPOXIDE—AN INTERMEDIATE FOR FORMING FULLEROL

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Bulbuls and crows provide complementary seed dispersal for China's endangered trees

Background: Different functional frugivores generally exhibit unequal contributions,both in terms of quantity(seed removal) and quality(seedling recruitment),to effective seed dispersal of plant species.However,variations in this dispersal pattern generated by frugivores across different regions are still unknown.Methods: In our study,we evaluated the contributions of two functional frugivore bird groups,the bulbuls(Pycnon?otidae) and crows(Corvidae),in both the seed removal and seedling recruitment of the endangered Chinese yew tree(Taxus chinensis) across three different geographical regions in eastern China.Results: The dominant crow species,Urocissa erythrorhyncha,was the most common disperser crow species at all sites,while the dominant bulbul species varied across the three sites.Furthermore,the two functional groups of dispersers diverged in the aspects of seed removal(quantity) and seedling recruitment pattern(quality).While bulbuls outperformed crows in seed removal(quantity),crows took more seeds to a safer site for seedlings(quality).Conclusions: Our results highlight the importance of variations in the effective seed dispersal patterns of different functional disperser groups across different regions in the conservation and management of endangered tree species.

CRISPR/dCas-mediated gene activation toolkit development and its application for parthenogenesis induction in maize

Clustered regularly interspaced short palindromic repeats(CRISPR)-Cas systems can be engineered as programmable transcription factors to either activate(CRISPRa)or inhibit transcription.Apomixis is extremely valuable for the seed industry in breeding clonal seeds with pure genetic backgrounds.We report here a CRISPR/dCas9-based toolkit equippedwith dCas9-VP64 andMS2-p65-HSF1 effectors that may specifically target genes with high activation capability.We explored the application of in vivo CRISPRa targeting of maize BABY BOOM2(ZmBBM2),acting as a fertilization checkpoint,as a means to engineer parthenogenesis.We detected ZmBBM2 transcripts only in egg cells but not in other maternal gametic cells.Activation of ZmBBM2 in egg cells in vivo caused maternal cell-autonomous parthenogenesis to produce haploid seeds.Our work provides a highly specific gene-activation CRISPRa technology for target cells and verifies its application for parthenogenesis induction in maize.