The search for the ideal biocatalyst

While the use of enzymes as biocatalysts to assist in the industrial manufacture of fine chemicals and pharmaceuticals has enormous potential, application is frequently limited by evolution-led catalyst traits. The advent of designer biocatalysts, produced by informed selection and mutation through recombinant DNA technology, enables production of process-compatible enzymes. However, to fully realize the potential of designer enzymes in industrial applications, it will be necessary to tailor catalyst properties so that they are optimal not only for a given reaction but also in the context of the industrial process in which the enzyme is applied

Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

Na3V2(PO4)3 particles partly embedded in carbon nanofibers with superb kinetics for ultra-high power sodium ion batteries

We here describe the extraordinary performance of NASICON Na3V2(PO4)3-carbon nanofiber (NVP-CNF) composites with ultra-high power and excellent cycling performance. NVP-CNFs are composed of CNFs at the center part and partly embedded NVP nanoparticles in the shell. We first report this unique morphology of NVP-CNFs for the electrode material of secondary batteries as well as for general energy conversion materials. Our NVP-CNFs show not only a high discharge capacity of approx. 88.9 mA h g-1 even at a high current density of 50 C but also approx. 93% cyclic retention property after 300 cycles at 1 C. The superb kinetics and excellent cycling performance of the NVP-CNFs are attributed to the facile migration of Na ions through the partly exposed regions of NVP nanoparticles that are directly in contact with an electrolyte as well as the fast electron transfer along the conducting CNF pathways

Controlling Solid-Electrolyte-Interphase Layer by Coating P‑Type Semiconductor NiO_<i>x</i> on Li₄Ti₅O₁₂ for High-Energy-Density Lithium-Ion Batteries

Li₄Ti₅O₁₂ is a promising anode material for rechargeable lithium batteries due to its well-known zero strain and superb kinetic properties. However, Li₄Ti₅O₁₂ shows low energy density above 1 V vs Li⁺/Li. In order to improve the energy density of Li₄Ti₅O₁₂, its low-voltage intercalation behavior beyond Li₇Ti₅O₁₂ has been demonstrated. In this approach, the extended voltage window is accompanied by the decomposition of liquid electrolyte below 1 V, which would lead to an excessive formation of solid electrolyte interphase (SEI) films. We demonstrate an effective method to improve electrochemical performance of Li₄Ti₅O₁₂ in a wide working voltage range by coating Li₄Ti₅O₁₂ powder with p-type semiconductor NiO_<i>x</i>. Ex situ XRD, XPS, and FTIR results show that the NiO_<i>x</i> coating suppresses electrochemical reduction reactions of the organic SEI components to Li₂CO₃, thereby promoting reversibility of the charge/discharge process. The NiO_<i>x</i> coating layer offers a stable SEI film for enhanced rate capability and cyclability

Bifunctional Li4Ti5O12 coating layer for the enhanced kinetics and stability of carbon anode for lithium rechargeable batteries

We introduce an effective way to improve the electrochemical properties of graphite anodes by Li4Ti5O12 (LTO) coating for lithium rechargeable batteries. LTO coated graphite is prepared by a sol-gel method coupled with hydrothermal reaction. LTO coating renders the electrochemical performance of graphite to be significantly improved compared to pristine graphite. Moreover, LTO coating layers affect the stability of the solid electrolyte interphase (SEI) by making an even SEI film without further electrolyte decomposition and thus making it more stable. Also, LTO coating layers prevent the electrolyte decomposition species from going into the interior graphite, proving that LTO coating can contribute to not only the electrochemical properties of graphite but also its thermal stability.close0

Tailored Oxygen Framework of Li₄Ti₅O₁₂ Nanorods for High-Power Li Ion Battery

Here we designed the kinetically favored Li₄Ti₅O₁₂ by modifying its crystal structure to improve intrinsic Li diffusivity for high power density. Our first-principles calculations revealed that the substituted Na expanded the oxygen framework of Li₄Ti₅O₁₂ and facilitated Li ion diffusion in Li₄Ti₅O₁₂ through 3-D high-rate diffusion pathway secured by Na ions. Accordingly, we synthesized sodium-substituted Li₄Ti₅O₁₂ nanorods having not only a morphological merit from 1-D nanostructure engineering but also sodium substitution-induced open framework to attain ultrafast Li diffusion. The new material exhibited an outstanding cycling stability and capacity retention even at 200 times higher current density (20 C) compared with the initial condition (0.1 C)

Hollow Sn–SnO₂ Nanocrystal/Graphite Composites and Their Lithium Storage Properties

Hollow spheres have been constructed by applying the Kirkendall effect to Sn nanocrystals. This not only accommodates the detrimental volume expansion but also reduces the Li⁺ transport distance enabling homogeneous Li–Sn alloying. Hollow Sn–SnO₂ nanocrystals show a significantly enhanced cyclic performance compared to Sn nanocrystal alone due to its typical structure with hollow core. Sn–SnO₂/graphite nanocomposites obtained by the chemical reduction and oxidation of Sn nanocrystals onto graphite displayed very stable cyclic performance thanks to the role of graphite as an aggregation preventer as well as an electronic conductor

Structurally and electronically designed TiO2Nx nanofibers for lithium rechargeable batteries

The morphology and electronic structure of metal oxides, including TiO 2 on the nanoscale, definitely determine their electronic or electrochemical properties, especially those relevant to application in energy devices. For this purpose, a concept for controlling the morphology and electrical conductivity in TiO2, based on tuning by electrospinning, is proposed. We found that the 1D TiO2 nanofibers surprisingly gave higher cyclic retention than 0D nanopowder, and nitrogen doping in the form of TiO2Nx also caused further improvement. This is due to higher conductivity and faster Li+ diffusion, as confirmed by electrochemical impedance spectra. Our findings provide an effective and scalable solution for energy storage efficiency. © 2013 American Chemical Society

Tailored Surface Structure of LiFePO₄/C Nanofibers by Phosphidation and Their Electrochemical Superiority for Lithium Rechargeable Batteries

We offer a brand new strategy for enhancing Li ion transport at the surface of LiFePO₄/C nanofibers through noble Li ion conducting pathways built along reduced carbon webs by phosphorus. Pristine LiFePO₄/C nanofibers composed of 1-dimensional (1D) LiFePO₄ nanofibers with thick carbon coating layers on the surfaces of the nanofibers were prepared by the electrospinning technique. These dense and thick carbon layers prevented not only electrolyte penetration into the inner LiFePO₄ nanofibers but also facile Li ion transport at the electrode/electrolyte interface. In contrast, the existing strong interactions between the carbon and oxygen atoms on the surface of the pristine LiFePO₄/C nanofibers were weakened or partly broken by the adhesion of phosphorus, thereby improving Li ion migration through the thick carbon layers on the surfaces of the LiFePO₄ nanofibers. As a result, the phosphidated LiFePO₄/C nanofibers have a higher initial discharge capacity and a greatly improved rate capability when compared with pristine LiFePO₄/C nanofibers. Our findings of high Li ion transport induced by phosphidation can be widely applied to other carbon-coated electrode materials