In recent years, micrometer‐sized Si‐based anode materials have attracted intensive attention in the pursuit of energy‐storage systems with high energy and low cost. However, the significant volume ...variation during repeated electrochemical (de)alloying processes will seriously damage the bulk structure of SiOx microparticles, resulting in rapid performance fade. This work proposes to address the challenge by preparing in situ magnesium‐doped SiOx (SiMgyOx) microparticles with stable structural evolution against Li uptake/release. The homogeneous distribution of magnesium silicate in SiMgyOx contributes to building a bonding network inside the particle so that it raises the modulus of lithiated state and restrains the internal cracks due to electrochemical agglomeration of nano‐Si. The prepared micrometer‐sized SiMgyOx anode shows high reversible capacities, stable cycling performance, and low electrode expansion at high areal mass loading. A 21700 cylindrical‐type cell based on the SiMgyOx‐graphite anode and LiNi0.8Co0.15Al0.05O2 cathode demonstrates a 1000‐cycle operation life using industry‐recognized electrochemical test procedures, which meets the practical storage requirements for consumer electronics and electric vehicles. This work provides insights on the reasonable structural design of micrometer‐sized alloying anode materials toward realization of high‐performance Li‐ion batteries.
The in situ element doping approach developed in this research provides not only a promising material (SiMgyOx) as high‐performance Li‐ion battery anodes with superior properties and low industrialization cost for commercial applications, but also insights on the reasonable structural design of micrometer‐sized alloying anode materials for restraining internal cracks and improving electrochemical performance.
Slot‐die coating is recognized as the most compatible method for the roll‐to‐roll (R2R) processing of large‐area flexible organic solar cells (OSCs). However, the photovoltaic performance of ...large‐area flexible OSC lags significantly behind that of traditional spin‐coating devices. In this work, two acceptors, Qx‐1 and Qx‐2, show quite different film‐formation kinetics in the slot‐die coating process. In situ absorption spectroscopy indicates that the excessive crystallinity of Qx‐2 provides early phase separation and early aggregation, resulting in oversized crystal domains. Consequently, the PM6:Qx‐1‐based 1 cm2 flexible device exhibits an excellent power conversion efficiency (PCE) of 13.70%, which is the best performance among the slot‐die‐coated flexible devices; in contrast, the PM6:Qx‐2 blend shows a pretty poor efficiency, which is lower than 1%. Moreover, the 30 cm2 modules based on PM6:Qx‐1, containing six 5 cm2 sub‐cells, exhibit a PCE of 12.20%. After being stored in a glove box for over 6000 h, the PCE remains at 103% of its initial values, indicating excellent shelf stability. Therefore, these results show a promising future strategy for the upscaling fabrication of flexible large‐area OSCs.
In situ absorption measurement is used to investigate the aggregation behavior of acceptors during slot‐die‐coating. The 1 cm2 flexible device can reach a power conversion efficiency of 13.70%, with excellent shelf stability and upscaling ability. The connected modules (180 cm2) can effectively power a smartphone, showing great potential for future applications.
Ionic current rectification (ICR) based nanopipettes allow accurate monitoring of cellular behavior in single living cells. Herein, we proposed a 30 nm nanopipette functionalized with G‐quadruplex ...DNAzyme as an efficient biomimetic recognizer for ROS generation at subcellular level via the changes of current–voltage relationship. Taking advantages of the ultra‐small tip, the nanopipette could penetrate into a single living cell repeatedly or keep measuring for a long time without compromising the cellular functions. Coupled with precision nanopositioning system, generation of ROS in mitochondria in response to cell inflammation was determined with high spatial resolution. Meanwhile, the changes of aerobic metabolism in different cell lines under drug‐induced oxidative stress were monitored continuously. We believe that the ICR‐nanopipette could be developed as a powerful approach for the study of cellular activities via electrochemical imaging in living cells.
Electrochemical imaging: An ionic current rectification (ICR) based nanopipette with a 30 nm nanotip was fabricated for continuous monitoring of aerobic metabolism processes in single living cells at subcellular level. The cells produced reactive oxygen species (ROS) in mitochondria. The inner surface of the nanopipette was functionalized with G‐quadruplex DNAzyme.
To better inform efforts to treat and control the current outbreak with a comprehensive characterization of COVID-19.
We searched PubMed, EMBASE, Web of Science, and CNKI (Chinese Database) for ...studies published as of March 2, 2020, and we searched references of identified articles. Studies were reviewed for methodological quality. A random-effects model was used to pool results. Heterogeneity was assessed using I2. Publication bias was assessed using Egger's test.
43 studies involving 3600 patients were included. Among COVID-19 patients, fever (83.3% 95% CI 78.4–87.7), cough (60.3% 54.2–66.3), and fatigue (38.0% 29.8–46.5) were the most common clinical symptoms. The most common laboratory abnormalities were elevated C-reactive protein (68.6% 58.2–78.2), decreased lymphocyte count (57.4% 44.8–69.5) and increased lactate dehydrogenase (51.6% 31.4–71.6). Ground-glass opacities (80.0% 67.3–90.4) and bilateral pneumonia (73.2% 63.4–82.1) were the most frequently reported findings on computed tomography. The overall estimated proportion of severe cases and case-fatality rate (CFR) was 25.6% (17.4–34.9) and 3.6% (1.1–7.2), respectively. CFR and laboratory abnormalities were higher in severe cases, patients from Wuhan, and older patients, but CFR did not differ by gender.
The majority of COVID-19 cases are symptomatic with a moderate CFR. Patients living in Wuhan, older patients, and those with medical comorbidities tend to have more severe clinical symptoms and higher CFR.
Abstract
N-doping plays an irreplaceable role in controlling the electron concentration of organic semiconductors thus to improve performance of organic semiconductor devices. However, compared with ...many mature p-doping methods, n-doping of organic semiconductor is still of challenges. In particular, dopant stability/processability, counterion-semiconductor immiscibility and doping induced microstructure non-uniformity have restricted the application of n-doping in high-performance devices. Here, we report a computer-assisted screening approach to rationally design of a triaminomethane-type dopant, which exhibit extremely high stability and strong hydride donating property due to its thermally activated doping mechanism. This triaminomethane derivative shows excellent counterion-semiconductor miscibility (counter cations stay with the polymer side chains), high doping efficiency and uniformity. By using triaminomethane, we realize a record n-type conductivity of up to 21 S cm
−1
and power factors as high as 51 μW m
−1
K
−2
even in films with thicknesses over 10 μm, and we demonstrate the first reported all-polymer thermoelectric generator.
Conjugated polymers usually form crystallized and amorphous regions in the solid state simultaneously, making it difficult to accurately determine their precise microstructures. The lack of ...multiscale microstructures of conjugated polymers limits the fundamental understanding of the structure–property relationships in polymer‐based optoelectronic devices. Here, crystals of two typical conjugated polymers based on four‐fluorinated benzodifurandione‐based oligo(p‐phenylene vinylene) (F4BDOPV) and naphthalenediimide (NDI) motifs, respectively, are obtained by a controlled self‐assembly process. The strong diffractivity of the polymer crystals brings an opportunity to determine the crystal structures by combining X‐ray techniques and molecular simulations. The precise polymer packing structures are useful as initial models to evaluate the charge transport properties in the ordered and disordered phases. Compared to the spin‐coated thin films, the highly oriented polymer chains in crystals endow higher mobilities with a lower hopping energy barrier. Microwire crystal transistors of F4BDOPV‐ and NDI‐based polymers exhibit high electron mobilities of up to 5.58 and 2.56 cm2 V−1 s−1, respectively, which are among the highest values in polymer crystals. This work presents a simple method to obtain polymer crystals and their precise microstructures, promoting a deep understanding of molecular packing and charge transport for conjugated polymers.
Conjugated polymer microwire crystals are obtained from solvated aggregates. The precise crystal packing and electronic structure in the polymer microwires are evaluated for understanding of the charge transport properties. Polymer crystal transistors of F4BDOPV‐2T exhibit higher electron mobilities of up to 5.58 cm2 V−1 s−1 with a much lower hopping energy barrier compared with conventional thin‐film transistors.
Kidneys are one of the targets for SARS-CoV-2, it is reported that up to 36% of patients with SARS-CoV-2 infection would develop into acute kidney injury (AKI). AKI is associated with high mortality ...in the clinical setting and contributes to the transition of AKI to chronic kidney disease (CKD). Up to date, the underlying mechanisms are obscure and there is no effective and specific treatment for COVID-19-induced AKI. In the present study, we investigated the mechanisms and interactions between Quercetin and SARS-CoV-2 targets proteins by using network pharmacology and molecular docking. The renal protective effects of Quercetin on COVID-19-induced AKI may be associated with the blockade of the activation of inflammatory, cell apoptosis-related signaling pathways. Quercetin may also serve as SARS-CoV-2 inhibitor by binding with the active sites of SARS-CoV-2 main protease 3CL and ACE2, therefore suppressing the functions of the proteins to cut the viral life cycle. In conclusion, Quercetin may be a novel therapeutic agent for COVID-19-induced AKI. Inhibition of inflammatory, cell apoptosis-related signaling pathways may be the critical mechanisms by which Quercetin protects kidney from SARS-CoV-2 injury.
Conjugated polymers with high thermoelectric performance enable the fabrication of low‐cost, large‐area, low‐toxicity, and highly flexible thermoelectric devices. However, compared to their p‐type ...counterparts, n‐type polymer thermoelectric materials show much lower performance, which is largely due to inefficient doping and a much lower conductivity. Herein, it is reported that the development of a donor–acceptor (D–A) polymer with enhanced n‐doping efficiency through donor engineering of the polymer backbone. Both a high n‐type electrical conductivity of 1.30 S cm−1 and an excellent power factor (PF) of 4.65 µW mK−2 are obtained, which are the highest reported values among D–A polymers. The results of multiple characterization techniques indicate that electron‐withdrawing modification of the donor units enhances the electron affinity of the polymer and changes the polymer packing orientation, leading to substantially improved miscibility and n‐doping efficiency. Unlike previous studies in which improving the polymer‐dopant miscibility typically resulted in lower mobilities, the strategy maintains the mobility of the polymer. All these factors lead to prominent enhancement of three orders magnitude in both the electrical conductivity and the PF compared to those of the non‐engineered polymer. The results demonstrate that proper donor engineering can enhance the n‐doping efficiency, electrical conductivity, and thermoelectric performance of D–A copolymers.
1000‐fold enhancements in n‐type electrical conductivity and power factor of a donor–acceptor copolymer are obtained by donor engineering. Donor engineering enhances electron affinity and n‐doping efficiency, prevents phase separation, lowers hopping barrier and keeps mobility unaffected. A record electrical conductivity of 1.30 S cm−1 and a power factor of 4.65 μW mK−2 are achieved in this work.
In December 2019, a new type viral pneumonia cases occurred in Wuhan, Hubei Province; and then named "2019 novel coronavirus (2019-nCoV)" by the World Health Organization (WHO) on 12 January 2020. ...For it is a never been experienced respiratory disease before and with infection ability widely and quickly, it attracted the world's attention but without treatment and control manual. For the request from frontline clinicians and public health professionals of 2019-nCoV infected pneumonia management, an evidence-based guideline urgently needs to be developed. Therefore, we drafted this guideline according to the rapid advice guidelines methodology and general rules of WHO guideline development; we also added the first-hand management data of Zhongnan Hospital of Wuhan University. This guideline includes the guideline methodology, epidemiological characteristics, disease screening and population prevention, diagnosis, treatment and control (including traditional Chinese Medicine), nosocomial infection prevention and control, and disease nursing of the 2019-nCoV. Moreover, we also provide a whole process of a successful treatment case of the severe 2019-nCoV infected pneumonia and experience and lessons of hospital rescue for 2019-nCoV infections. This rapid advice guideline is suitable for the first frontline doctors and nurses, managers of hospitals and healthcare sections, community residents, public health persons, relevant researchers, and all person who are interested in the 2019-nCoV.
Threshold switching (TS) devices are promising candidates to build highly compact and energy efficient artificial neurons. Here, we present a Pt/Ag/TiN/HfAlO x /Pt (PATHP) device with excellent TS ...characteristics, including a large selectivity(10 10 ), a wide range of operation current from 10 nA to 1 mA, an extremely steep slope (0.63 mV/dec) and fast turn-on speed (50 ns). The stable TS performance can be ascribed to the introduction of TiN buffer layer and the alternate atomic layer deposited HfAlOx layer. Further, we experimentally demonstrate the functions of leaky-integrate-and-fire neurons with low power feature based on a RC circuit and a single device, respectively, which are essential for constructing spiking neuromorphic systems.
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