3D‐Printed Cathodes of LiMn1−xFexPO4 Nanocrystals Achieve Both Ultrahigh Rate and High Capacity for Advanced Lithium‐Ion Battery

A 3D‐printing technology and printed 3D lithium‐ion batteries (3D‐printed LIBs) based on LiMn_0.21Fe_0.79PO₄@C (LMFP) nanocrystal cathodes are developed to achieve both ultrahigh rate and high capacity. Coin cells with 3D‐printed cathodes show impressive electrochemical performance: a capacity of 108.45 mAh g^?1 at 100 C and a reversible capacity of 150.21 mAh g^?1 at 10 C after 1000 cycles. In combination with simulation using a pseudo 2D hidden Markov model and experimental data of 3D‐printed and traditional electrodes, for the first time deep insight into how to achieve the ultrahigh rate performance for a cathode with LMFP nanocrystals is obtained. It is estimated that the Li‐ion diffusion in LMFP nanocrystal is not the rate‐limitation step for the rate to 100 C, however, that the electrolyte diffusion factors, such as solution intrinsic diffusion coefficient, efficiency porosity, and electrode thickness, will dominate ultrahigh rate performance of the cathode. Furthermore, the calculations indicate that the above factors play important roles in the equivalent diffusion coefficient with the electrode beyond a certain thickness, which determines the whole kinetic process in LIBs. This fundamental study should provide helpful guidance for future design of LIBs with superior electrochemical performance.     

Outstanding Low Temperature Thermoelectric Power Factor from Completely Organic Thin Films Enabled by Multidimensional Conjugated Nanomaterials

In an effort to create a paintable/printable thermoelectric material, comprised exclusively of organic components, polyaniline (PANi), graphene, and double‐walled nanotube (DWNT) are alternately deposited from aqueous solutions using the layer‐by‐layer assembly technique. Graphene and DWNT are stabilized with an intrinsically conductive polymer, poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). An 80 quadlayer thin film (≈1 μm thick), comprised of a PANi/graphene‐PEDOT:PSS/PANi/DWNT‐PEDOT:PSS repeating sequence, exhibits unprecedented electrical conductivity (σ ≈ 1.9 × 10⁵ S m^?1) and Seebeck coefficient (S ≈ 120 μV K^?1) for a completely organic material. These two values yield a thermoelectric power factor (PF = S ² σ ^?1) of 2710 μW m^?1 K^?2, which is the highest value ever reported for a completely organic material and among the highest for any material measured at room temperature. These outstanding properties are attributed to the highly ordered structure in the multilayer assembly. This water‐based thermoelectric nanocomposite is competitive with the best inorganic semiconductors (e.g., bismuth telluride) at room temperature and can be applied as a coating to any flexible surface (e.g., fibers in clothing). For the first time, there is a real opportunity to harness waste heat from unconventional sources, such as body heat, to power devices in an environmentally‐friendly way.     

Reduced dispersal and survival in the sweet potato weevil (Euscepes postfasciatus) after irradiation

相似文献   

Mercury uptake and phytotoxicity in terrestrial plants grown naturally in the Gumuskoy (Kutahya) mining area,Turkey

This study investigated mercury (Hg) uptake and transport from the soil to different plant parts by documenting the distribution and accumulation of Hg in the roots and shoots of 12 terrestrial plant species, all of which grow naturally in surface soils of the Gumuskoy Pb-Ag mining area. Plant samples and their associated soils were collected and analyzed for Hg content by ICP-MS. Mean Hg values in the soils, roots, and shoots of all plants were 6.914, 460, and 206 µg kg^?1, respectively and lower than 1. The mean enrichment factors for the roots (ECR) and shoots (ECS) of these plants were 0.06 and 0.09, respectively and lower than 1. These results show that the roots of the studied plants prevented Hg from reaching the aerial parts of the plants. The mean translocation factor (TLF) was 1.29 and higher than 1. The mean TLF values indicated that all 12 plant species had the ability to transfer Hg from the roots to the shoots but that transfer was more efficient in plants with higher ECR and ECS. Therefore, these plants could be useful for the biomonitoring of environmental pollution and for rehabilitating areas contaminated by Hg.     

Protein‐fold recognition using an improved single‐source K diverse shortest paths algorithm

Protein structure prediction, when construed as a fold recognition problem, is one of the most important applications of similarity search in bioinformatics. A new protein‐fold recognition method is reported which combines a single‐source K diverse shortest path (SSKDSP) algorithm with Enrichment of Network Topological Similarity (ENTS) algorithm to search a graphic feature space generated using sequence similarity and structural similarity metrics. A modified, more efficient SSKDSP algorithm is developed to improve the performance of graph searching. The new implementation of the SSKDSP algorithm empirically requires 82% less memory and 61% less time than the current implementation, allowing for the analysis of larger, denser graphs. Furthermore, the statistical significance of fold ranking generated from SSKDSP is assessed using ENTS. The reported ENTS‐SSKDSP algorithm outperforms original ENTS that uses random walk with restart for the graph search as well as other state‐of‐the‐art protein structure prediction algorithms HHSearch and Sparks‐X, as evaluated by a benchmark of 600 query proteins. The reported methods may easily be extended to other similarity search problems in bioinformatics and chemoinformatics. The SSKDSP software is available at http://compsci.hunter.cuny.edu/~leixie/sskdsp.html . Proteins 2016; 84:467–472. © 2016 Wiley Periodicals, Inc.     

Structure‐based classification of FAD binding sites: A comparative study of structural alignment tools

A total of six different structural alignment tools (TM‐Align, TriangleMatch, CLICK, ProBis, SiteEngine and GA‐SI) were assessed for their ability to perform two particular tasks: (i) discriminating FAD (flavin adenine dinucleotide) from non‐FAD binding sites, and (ii) performing an all‐to‐all comparison on a set of 883 FAD binding sites for the purpose of classifying them. For the first task, the consistency of each alignment method was evaluated, showing that every method is able to distinguish FAD and non‐FAD binding sites with a high Matthews correlation coefficient. Additionally, GA‐SI was found to provide alignments different from those of the other approaches. The results obtained for the second task revealed more significant differences among alignment methods, as reflected in the poor correlation of their results and highlighted clearly by the independent evaluation of the structural superimpositions generated by each method. The classification itself was performed using the combined results of all methods, using the best result found for each comparison of binding sites. A number of different clustering methods (Single‐linkage, UPGMA, Complete‐linkage, SPICKER and k‐Means clustering) were also used. The groups of similar binding sites (proteins) or clusters generated by the best performing method were further analyzed in terms of local sequence identity, local structural similarity and conservation of analogous contacts with the FAD ligands. Each of the clusters was characterized by a unique set of structural features or patterns, demonstrating that the groups generated truly reflect the structural diversity of FAD binding sites. Proteins 2016; 84:1728–1747. © 2016 Wiley Periodicals, Inc.     

Competition and facilitation between Australian and Spanish legumes in seven Australian soils

This paper evaluates the relative performance and competitive ability of seven legumes from the Iberian Peninsula, Spain (one already invasive in Australia), grown singly or pairwise with seven legumes from south‐western Australia in their own soils. Indices of growth used were root, shoot and total mass and shoot dimensions. Water content, xylem water potential during drying and nodule production were also measured. The index of competition used was the intensity of competition coefficient (ICC), which is suitable for additive designs. The Australian species usually grew larger than the Spanish species, in their presence or absence, although the results were sensitive to the index of growth or resource capture used. The Australian legumes usually possessed greater total water content than the co‐occurring Spanish legumes. At least five Australian species were less reduced or not affected at all by inter‐regional competition compared with growth in isolation. Two Australian legumes performed relatively poorly in the presence of at least four Spanish legumes. The ICC identified many instances of growth promotion (facilitation) of the Australian species, which we attribute to extra nitrogen obtained through enhanced nodulation of both cohabiting species. Five of the seven Spanish species were outcompeted by the Australian species, whereas the growth of two was sometimes facilitated. Although the Spanish legumes had greater competitive ability in the more fertile Australian soils, they remained competitively inferior to the Australian legumes in their first season of growth and none is likely to displace the native legumes at this stage of growth. Longer‐term field studies are needed to fully evaluate the potential invasiveness of perennial legumes.     

皮肤组织模型中吸收和散射系数对单线态氧发光特性的影响

构建由脂肪乳剂和墨水组成的皮肤组织模型,定量研究皮肤组织模型的吸收系数μa和散射系数μs对光敏化单线态氧(singlet oxygen,~1O_2)发光特性的影响。利用~1O_2发光检测系统测量含光敏剂四硫磺基酞菁氯化铝的皮肤组织模型分别在中心波长为1 230,1 270和1 310 nm处的时间分辨发光光谱,对扣除背景信号后的时间分辨~1O_2发光光谱进行积分和拟合,获得~1O_2发光积分强度以及激发三重态寿命τ_T和~1O_2寿命τ_D。结果表明在皮肤组织模型中,~1O_2发光积分强度随着μ_a和μ_s的增大而减小,μ_a对τ_T和τ_D没有影响。τ_T随着μs的增加而增加,τ_D随μ_s的增加先骤降而后缓慢上升。当μ_a1.5 mm~(-1)和μ_s32 cm~(-1)时,~1O_2发光积分强度和τ_T、τ_D均趋于稳定,其中τ_T和τ_D分别为3.4±0.6μs和3.3±0.7μs。     

Similarities between invaders and native species: Moving past Darwin's naturalization conundrum

Darwin's naturalization conundrum states that successful invaders must be closely related to native species to possess the traits to tolerate that environment, but distantly related enough to possess traits allowing exploitation of underutilized niches, thereby minimizing competition. Although influential, this hypothesis is based on several simplistic assumptions. In particular, the relationship among phylogenetic relatedness, similarity, and competition is more complex than assumed and changes with spatial and phylogenetic scale. Competitive interactions are determined by limiting similarity and trait hierarchies associated with separate traits. Successful invaders thus need to be similar to native species in some respects, but different in others. This combination of similarities and differences is unlikely to be conserved. Further, many invasive species are represented in their novel range by genotypes with extreme trait values or plasticity relative to the species mean. Selection for these genotypes may alter the similarity between invasive and native species, thus obscuring the relationship between competition and phylogenetic relatedness. As environmental filtering and competition often act on different spatial scales, approaches assessing how individual traits relate to invasion at these scales (species pools vs local community) may improve our understanding of the relationship between similarity and invasion.