Lithium Storage Performance of Hard Carbons Anode Materials Prepared by Different Precursors

以聚丙烯腈、石油沥青和花生壳为前驱体,在1200℃下碳化制备三种不同的硬碳材料。通过扫描电子显微、X射线衍射、氮气吸附/脱附测试和拉曼光谱等方法探究不同前驱体所制备的硬碳材料的表面形貌和物相结构。通过恒流充放电测试考察了这三种硬碳负极材料的电化学性能。结果表明,花生壳基硬碳的初始放电比容量最高,但首圈库仑效率最低,石油沥青基硬碳的首圈库仑效率最高但是比容量最低,聚丙烯腈基硬碳具有较高的循环比容量和稳定性。Hard carbon is one of the most promising anode material for lithium ion batteries (LIBs) owing to its high stability, widespread availability, low-cost, and excellent performance. The electrochemical properties of hard carbon materials depend strongly on the type of precursors. It is, therefore, very important to choose an excellent hard carbon precursor. Polyacrylonitrile, petroleum pitch and peanut shells were used as raw materials to prepare different hard carbon anode materials for LIBs. These hard carbon anode materials were successfully synthesized in two steps. The selected precursor was firstly carbonized at 600℃ for 1 h in argon atmosphere using heating rate of 1℃·min-1, and then was further carbonized at 1200℃ for 1h in argon atmosphere using heating rate of 5℃·min-1. Under such a low heating rate, a relatively small specific surface area could be obtained as much as possible for the hard carbon anode material. The surface morphology and phase structure of as synthesized hard carbon materials were analyzed by scanning electron microscopy, X-ray diffractometer, nitrogen adsorption analyzer and Raman spectrometer. The ion carrier storage mechanism was further investigated using cyclic voltammetry by examining whether the ion insertion/extraction mechanism is surface-controlled pseudocapacitance or diffusion-limited intercalation. It was further verified that the lithium storage mechanism of hard carbon anode materials is in line with the “adsorption-intercalation” mechanism. The results indicated that polyacrylonitrile-derived hard carbon anode material had low impedance by EIS test. This may be the reason why the low voltage platform of polyacrylonitrile-derived hard carbon materials had a higher specific capacity. The electrochemical performance of different hard carbon materials were investigated through galvanostatic charge and discharge tests. The peanut shell-derived hard carbon material showed the highest initial specific capacity (579.1 mAh·g-1), but the lowest initial coulombic efficiency (49.35%). The petroleum pitch-derived one delivered the highest initial coulombic efficiency (85.97%), but the lowest initial specific capacity (301.7 mAh·g-1). Comparing the cycle performance of these three hard carbon materials, polyacrylonitrile-derived hard carbon materials exhibited the excellent cycling performance (87.17% of capacity over 500 cycles). This study would provide useful assistance to understand the precursor-derived electrochemical properties of hard carbon anode material in practical applications.国家自然科学基金面上项目(21673051);广东省科技厅国际合作项目资助(2019A050510043);广东省科技厅产学研重大专项(2017B010119003)通讯作者:施志聪E-mail:[email protected]:Zhi-CongShiE-mail:[email protected]广东工业大学材料与能源学院,新能源材料与器件系,广东 广州 510000Department of New Energy Materials and Devices, School of Materials and Energy, Guangdong University of Technology, Guangzhou 510000, Guangdong, Chin

ALS/FTD Mutation-Induced Phase Transition of FUS Liquid Droplets and Reversible Hydrogels into Irreversible Hydrogels Impairs RNP Granule Function.

The mechanisms by which mutations in FUS and other RNA binding proteins cause ALS and FTD remain controversial. We propose a model in which low-complexity (LC) domains of FUS drive its physiologically reversible assembly into membrane-free, liquid droplet and hydrogel-like structures. ALS/FTD mutations in LC or non-LC domains induce further phase transition into poorly soluble fibrillar hydrogels distinct from conventional amyloids. These assemblies are necessary and sufficient for neurotoxicity in a C. elegans model of FUS-dependent neurodegeneration. They trap other ribonucleoprotein (RNP) granule components and disrupt RNP granule function. One consequence is impairment of new protein synthesis by cytoplasmic RNP granules in axon terminals, where RNP granules regulate local RNA metabolism and translation. Nuclear FUS granules may be similarly affected. Inhibiting formation of these fibrillar hydrogel assemblies mitigates neurotoxicity and suggests a potential therapeutic strategy that may also be applicable to ALS/FTD associated with mutations in other RNA binding proteins.Supported by Canadian Institutes of Health Research (PEF, PStGH), Alzheimer Society of Ontario (PEF, PStGH), Wellcome Trust (PStGH, MEV, CFK, GSK, DR, CEH), Medical Research Council (PStGH, MEV, CFK, GSK), National Institutes of Health Research, Alzheimer Research UK (CFK, GSK), Gates Cambridge Scholarship (JQL), Engineering and Physical Sciences Research Council (CFK, GSK), European Research Council Starting Grant RIBOMYLOME_309545 (GGT), European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement no. 322817 (CEH), and National Institute of Neurological Disorders and Stroke R01 NS07377 (NAS). The authors thank Tom Cech and Roy Parker for helpful discussions.This is the final version of the article. It was first available from Elsevier via http://dx.doi.org/10.1016/j.neuron.2015.10.03

Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe