Regulating the size and assembled structure of graphene building blocks for high-performance silicon nanocomposite anodes

Silicon-based composites have received significant interest as a high-capacity anode material for high-performance lithium-ion batteries. However, the large volume change during prolonged charge/discharge cycles, poor electric conductivity, and unstable solid electrolyte interface of the Si electrodes lead to performance degradations, such as fast capacity decay and low coulombic efficiency (CE). It\u27s promising but challenging to fabricate Si-based composite anodes with a high Si active material, which enables high energy density, high-rate capability, and good cycling stability. Herein, the size effect of mechanically robust and highly conductive graphene sheets was investigated to effectively regulate the charge transport kinetics, volume changes, first cycle CE, and stable solid-electrolyte-interphase of the Si-anode for improved electrochemical performance. Specifically, our developed nanocomposite electrode (Si@ULG) consisting of Si nanoparticles (NPs) enveloped by ultra-large graphene sheets (ULG) can deliver a specific capacity of 1478 mA h g−1 even after 200 cycles at C/5, with a low capacity loss of 0.23% per cycle. This outstanding cycling performance surpasses that of electrodes wrapped by small (SG) or large graphene sheets (LG). By further assembling ULG sheets as building blocks into a three-dimensional (3D) graphene framework to load a high weight percentage of graphene-wrapped Si materials (e.g., Si@ULG), the as-prepared binder-free 3D Si@ULG-ULG nanocomposite electrode (with a high mass loading of 3 mg cm−2) enabled an areal capacity of 2.1 mA h cm−2 after 200 cycles at C/5, which is much higher than the slurry coating thin-film anodes (e.g., 0.12 mA h cm−2) at low areal mass loading (0.49 mg cm−2)

Identification and expression of cysteine sulfite decarboxylase genes and their response to hyposalinity stress in Ruditapes philippinarum

Cysteine sulfinate decarboxylase (CSAD) is a rate-limiting enzyme in taurine biosynthesis. In this study, the structure and expression characteristics of the RpCSAD gene in Ruditapes philippinarum were analyzed. The pyridoxal phosphate (PLP)-dependent amino acid carboxylase structural domains and catalytic active sites of six copies of RpCSAD were highly conserved. Tissue expression analysis demonstrated that RpCSAD1 and RpCSAD3-6 was primarily expressed in the mantle tissue, and RpCSAD2 in the water tube and gonad tissue. After exposure to hyposalinity stress, the expression levels of RpCSADs were found to be upregulated in all three shell-colored groups of clams. Remarkably, there was a pronounced increase in the expression of RpCSAD1-6 observed specifically in the zebra shell-color groups. These findings strongly suggest the involvement of taurine metabolism in the response of zebra shell-color clams to low salinity stress, thereby emphasizing its critical role in the adaptation mechanisms. These findings could contribute to a better understanding the mechanisms of osmotic stress tolerance in shellfish

of Thermal Stability of Copper Oxide Nanowires at Anaerobic Environment

Many metal oxides with promising electrochemical properties were developed recently. Before those metal oxides realize the use as an anode in lithium ion batteries, their thermal stability at anaerobic environment inside batteries should be clearly understood for safety. In this study, copper oxide nanowires were investigated as an example. Several kinds of in situ experiment methods including in situ optical microscopy, in situ Raman spectrum, and in situ transmission electron microscopy were adopted to fully investigate their thermal stability at anaerobic environment. Copper oxide nanowires begin to transform as copper(I) oxide at about 250 ∘ C and finish at about 400 ∘ C. The phase transformation proceeds with a homogeneous nucleation

Interannual variability of air-sea CO2 exchange in the Northern Yellow Sea and its underlying mechanisms

A three-dimensional (3-D) physical-biogeochemical-carbon cycle coupled model is used to investigate the interannual variability of the air-sea carbon dioxide (CO2) flux (FCO2) in the Northern Yellow Sea (NYS) from 2009 to 2018. The verification of the model indicate that the simulation results for multiple variables exhibit consistency and fit well with the observed data. The study show that although the multi-year average FCO2 in the NYS is close to the source-sink balance, there are obvious interannual differences between different years. In particular, a relatively strong source of atmospheric CO2 (1.0 mmol m–2 d–1) is exhibited in 2014, while a relatively strong sink of atmospheric CO2 (–0.7 mmol m–2 d–1) emerges in 2016. Mechanism analysis indicates that the abnormally high temperature is the main controlling factor for the relatively high CO2 efflux rate in the NYS in 2014, while the abnormally low dissolved inorganic carbon (DIC) concentration is the main factor contributing to the relatively high CO2 influx rate in 2016. Further analysis reveals that the primary reason for the low DIC concentration since the onset of winter in 2016 is the high net decrease rate of DIC in the NYS in 2015, influenced by net community production in the summer and advection processes during the autumn. The abnormally high primary production during the summer of 2015 results in the excessive reduction of DIC concentration through biological processes. In addition, due to the strong northeasterly wind event in November 2015, low-concentration-DIC water from the Yellow Sea (YS) extends into the Bohai Sea (BS). This further leads to higher DIC flux from the NYS into the BS in the upper mixed layer and increases the inflow of low-concentration-DIC water from the Southern Yellow Sea (SYS) into the NYS. These ultimately result in the abnormal reduction of DIC concentration in the upper mixed layer of the NYS during the autumn of 2015. This study enriches our understanding of interannual variability of FCO2 in the NYS, which will not only help to further reveal the variations of FCO2 under human activities and climate change, but also provide useful information for guiding the comprehensive assessment of the carbon budget

In Situ

Many metal oxides with promising electrochemical properties were developed recently. Before those metal oxides realize the use as an anode in lithium ion batteries, their thermal stability at anaerobic environment inside batteries should be clearly understood for safety. In this study, copper oxide nanowires were investigated as an example. Several kinds of in situ experiment methods including in situ optical microscopy, in situ Raman spectrum, and in situ transmission electron microscopy were adopted to fully investigate their thermal stability at anaerobic environment. Copper oxide nanowires begin to transform as copper(I) oxide at about 250°C and finish at about 400°C. The phase transformation proceeds with a homogeneous nucleation

Observation of topological electronic structure in quasi-1D superconductor TaSe3

Topological superconductors (TSCs), with the capability to host Majorana bound states that can lead to non-Abelian statistics and application in quantum computation, have been one of the most intensively studied topics in condensed matter physics recently. Up to date, only a few compounds have been proposed as candidates of intrinsic TSCs, such as doped topological insulator CuxBi2Se3 and iron-based superconductor FeTe0.55Se0.45. Here, by carrying out synchrotron and laser based angle-resolved photoemission spectroscopy (ARPES), we systematically investigated the electronic structure of a quasi-1D superconductor TaSe3, and identified the nontrivial topological surface states. In addition, our scanning tunneling microscopy (STM) study revealed a clean cleaved surface with a persistent superconducting gap, proving it suitable for further investigation of potential Majorana modes. These results prove TaSe3 as a stoichiometric TSC candidate that is stable and exfoliable, therefore a great platform for the study of rich novel phenomena and application potentials.Comment: to appear in Matte

Measuring effects on intima-media thickness: an evaluation of rosuvastatin in Chinese subjects with subclinical atherosclerosis—design, rationale, and methodology of the METEOR-China study

BACKGROUND: The beneficial effect of statins on atherosclerosis and cardiovascular outcomes has been well established. The Measuring Effects on intima media Thickness: an Evaluation Of Rosuvastatin (METEOR) global study demonstrated that a 2-year orally administered treatment with rosuvastatin 40 mg daily significantly slowed the progression of carotid intima-media thickness (CIMT) compared to placebo. The current METEOR-China study is designed to evaluate the effect of rosuvastatin 20 mg daily versus placebo on the progression of atherosclerosis measured by CIMT in asymptomatic Chinese subjects. METHODS: This is a phase 3, randomised, double-blind, placebo-controlled, multicentre parallel-group study. Asymptomatic Chinese subjects with a 10-year ischaemic cardiovascular disease (ICVD) risk < 10% will be recruited at 25 study sites. They will be treated with rosuvastatin 20 mg or placebo for 104 weeks. The primary endpoint is the annualised rate of change in CIMT measured by B-mode ultrasonography. Secondary endpoints include the annualised rate of change in CIMT at three different sections of the carotid artery and changes in the serum lipid profile. Safety parameters will also be assessed. CONCLUSION: The study will evaluate whether rosuvastatin 20 mg slows the progression of CIMT in asymptomatic Chinese subjects at low risk of ICVD. TRIAL REGISTRATION: ClinicalTrials.gov NCT02546323 . Registered on September 10, 2015

Rosuvastatin Slows Progression of Carotid Intima-Media Thickness: The METEOR-China Randomized Controlled Study

Background: Atherosclerosis is the leading cause of cardiovascular disease worldwide, including in China. Primary prevention, through lipid-lowering, could avert development of atherosclerosis. Carotid intima-media thickness (CIMT) is a well-validated measure of atherosclerosis used in intervention studies as the primary outcome and alternative end point for cardiovascular disease events. Methods: This randomized, double-blind, placebo-controlled, multicenter, parallel-group study assessed the effects of rosuvastatin 20 mg/d compared with placebo on progression of CIMT over 104 weeks in Chinese people with subclinical atherosclerosis. The primary end point was the annualized rate of change in mean of the maximum CIMT measurements taken 7× over the study period from each of 12 carotid artery sites (near and far walls of the right and left common carotid artery, carotid bulb, and internal carotid artery). Secondary end points included CIMT changes at different artery sites and lipid-parameter changes. Safety was also assessed. Results: Participants were randomized (1:1) to receive rosuvastatin (n=272) or placebo (n=271). Baseline characteristics were well balanced between groups. The change in mean of the maximum CIMT of the 12 carotid sites was 0.0038 mm/y (95% CI, -0.0023-0.0100) for the rosuvastatin group versus 0.0142 mm/y (95% CI, 0.0080-0.0204) for the placebo group, with a difference of -0.0103 mm/y (95% CI, -0.0191 to -0.0016; P=0.020). For the CIMT secondary end points, the results were generally consistent with the primary end point. There were clinically relevant improvements in lipid parameters with rosuvastatin. We observed an adverse-event profile consistent with the known safety profile of rosuvastatin. Conclusions: Rosuvastatin 20 mg/d significantly reduced the progression of CIMT over 2 years in Chinese adults with subclinical atherosclerosis and was well tolerated. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02546323