No abstract

Well-defined poly(2-(methacryloyloxy)ethyl ferrocenecarboxylate) (PFcMA) brushes were synthesized by surface-initiated atom transfer radical polymerization (SI-ATRP) on cross-linked polystyrene particles. The ATRP of FcMA monomer was reinvestigated leading to molar masses up to 130 kg mol–1 with a good reaction control and high monomer conversion (91%). The SI-ATRP was done with different amounts of initiator in the PS particle shell leading to PFcMA surface conformations from “mushroom-like” to dense “brush-like” polymers, which could be confirmed by dynamic light scattering (DLS) experiments. Redox-responsive behavior of the PFcMA shell was investigated by DLS and cyclic voltammetry (CV) measurements indicating a tremendous increase in the hydrodynamic volume of the ferrocene-containing shell. The transformation of PFcMA-grafted PS particles to magnetic iron oxides after thermal treatment could be investigated by SQUID magnetization measurements showing the typical hysteresis for ferromagnetic material.

The desire to understand how the brain generates and patterns behavior has driven rapid methodological innovation in tools to quantify natural animal behavior. While advances in deep learning and computer vision have enabled markerless pose estimation in individual animals, extending these to multiple animals presents unique challenges for studies of social behaviors or animals in their natural environments. Here we present Social LEAP Estimates Animal Poses (SLEAP), a machine learning system for multi-animal pose tracking. This system enables versatile workflows for data labeling, model training and inference on previously unseen data. SLEAP features an accessible graphical user interface, a standardized data model, a reproducible configuration system, over 30 model architectures, two approaches to part grouping and two approaches to identity tracking. We applied SLEAP to seven datasets across flies, bees, mice and gerbils to systematically evaluate each approach and architecture, and we compare it with other existing approaches. SLEAP achieves greater accuracy and speeds of more than 800 frames per second, with latencies of less than 3.5 ms at full 1,024 × 1,024 image resolution. This makes SLEAP usable for real-time applications, which we demonstrate by controlling the behavior of one animal on the basis of the tracking and detection of social interactions with another animal.

Arecordpower conversion efficiency of 8.40 %was obtained in single-component organic solar cells (SCOSCs) based on double-cable conjugated polymers.T his is realized based on exciton separation playing the same role as charge transport in SCOSCs.T wo double-cable conjugated polymers were designed with almost identical conjugated backbones and electron-withdrawing side units,b ut extra Cl atoms had different positions on the conjugated backbones.W hen Cl atoms were positioned at the main chains,the polymer formed the twist backbones,e nabling better miscibility with the naphthalene diimide side units.T his improves the interface contact between conjugated backbones and side units,resulting in efficient conversion of excitons into free charges.T hese findings reveal the importance of charge generation process in SCOSCs and suggest as trategy to improve this process: controlling miscibility between conjugated backbones and aromatic side units in double-cable conjugated polymers.

A series of "double-cable" conjugated polymers were developed for application in efficient single-component polymer solar cells, in which high quantum efficiencies could be achieved due to the optimized nanophase separation between donor and acceptor parts. The new double-cable polymers contain electron-donating poly(benzodithiophene) (BDT) as linear conjugated backbone for hole transport and pendant electron-deficient perylene bisimide (PBI) units for electron transport, connected via a dodecyl linker. Sulfur and fluorine substituents were introduced to tune the energy levels and crystallinity of the conjugated polymers. The double-cable polymers adopt a "face-on" orientation in which the conjugated BDT backbone and the pendant PBI units have a preferential π-π stacking direction perpendicular to the substrate, favorable for interchain charge transport normal to the plane. The linear conjugated backbone acts as a scaffold for the crystallization of the PBI groups, to provide a double-cable nanophase separation of donor and acceptor phases. The optimized nanophase separation enables efficient exciton dissociation as well as charge transport as evidenced from the high-up to 80%-internal quantum efficiency for photon-to-electron conversion. In single-component organic solar cells, the double-cable polymers provide power conversion efficiency up to 4.18%. This is one of the highest performances in single-component organic solar cells. The nanophase-separated design can likely be used to achieve high-performance single-component organic solar cells.

Background:With the effective prevention and control of COVID -19 inChina, the number of cured cases increased significantly. Further monitoring of the disease prognosis and effective control of the "relapse" of the epidemic become the next focus of work. To analyse the clinical prognosis of discharged COVID-19 patients by monitoring their SAR-CoV-2 nucleic acid status, which may provide This article is protected by copyright. All rights reserved. Accepted Articleevidence to establish discharge standards and follow-up management for COVID-19 patients. Methods: We included 13 discharged COVID-19 patients who were quarantined for 4-week at home. The patient's daily clinical signs were recorded and sputum and faecal specimens were regularly sent for the detection of SARS-CoV-2 nucleic acid. Results: The time between initial symptoms and meeting discharge criteria was 18 -44 days with an average of 25 ± 6 days. The faecal samples of two patients still tested positive after meeting discharge criteria and the sputum samples of four patients returned positive 5 -14 days after discharge. The rate of a recurring positive test result in samples from the respiratory system was 31%(4/13). Conclusion:Under the present discharge criteria, the high presence of SARS-CoV-2 nucleic acid in faecal and respiratory samples of discharged COVID-19 patients indicate potential infectivity. Therefore, we suggest that faecal virus nucleic acid should be tested as a routine monitoring index for COVID-19 and a negative result be added to the criteria. Simultaneously, we should strengthen the regular follow-up of discharged patients with continuous monitoring of the recurrence of viral nucleic acid. Mainly engaged in the laboratory diagnostic technology research of infectious diseases. Data sharingWith the permission of the corresponding authors, we can provide participant data without names and identifers, but not the study protocol, statistical analysis plan, or informed consent form. Data can be provided after the article is published.Once the data can be made public, the research team will provide an email address for communication. The corresponding authors have the right to decide whether to share the data or not based on the research objectives and plan provided. ContributorsAll the authors participated in generating the idea. Bin Li ＆ Guanhua Hou took part in samples collection. Youjiang Li, Yingping Wu, and Xiaodong Zhang tested all samples by reverse transcription-polymerase chain reaction (RT-PCR) assay.Yuangyuang Yu took part in data collection and interpretation. Youjiang

Recently, lead halide perovskite (PVSK) polycrystalline films have drawn much attention as photoactive material and scored tremendous achievements in solar cells, photodetectors, light‐emitting diodes, and lasers owing to their engrossing optoelectronic properties and facile solution‐processed fabrication. However, large amounts of grain boundaries unfavorably induce ion migration, surface defect, and poor stability, impeding PVSK polycrystalline film‐based optoelectronic devices from practical application. In comparison with the polycrystalline counterparts, PVSK single crystals (SCs) with lower trap density serve as a better platform for not only fundamental research but also device applications. In light of this, the idea of using PVSK single crystals (SCs) to construct the optoelectronic devices is then proposed. Since then, a series of synthesis methods of PVSK SCs have emerged. In this review, recent progress of synthesis method of PVSK SCs is tried to be summarized and their advantages and limitations are analyzed. And then, the optoelectronic properties including carrier dynamic, defects, ion migration, and instability issues in these 3D and 2D PVSK SCs are overviewed and accordingly the proper device configurations of corresponding solar cells, photodetectors, X‐ray, γ‐ray detectors, etc., are proposed. It is believed that this review can provide the guidance for the further development of PVSK SCs and their applications.

oronavirus disease 2019 , the pathogen of which is severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a highly infectious disease that broke out in Wuhan, China, in December 2019 and has spread to more than 200 countries. 1 COVID-19 has been proven to be transmitted mainly through droplets and contact. 2 The eye is also considered an important route of infection.According to reports published in recent years, the prevalence of myopia in China is now more than 80% of the population. Wearing of eyeglasses is common among Chinese individuals of all ages. 3 However, since the outbreak of COVID-19 in Wuhan in December 2019, we observed that few patients with eyeglasses were admitted in the hospital ward. There-fore, we collected information on the wearing of eyeglasses from all inpatients with COVID-19 as part of their medical history and used the data to examine the association between wearing eyeglasses and COVID-19 infection. MethodsThis cohort study was approved by the ethics committee of Suizhou Zengdu Hospital, Suizhou, China, and followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline. Patients signed written informed consent and were not provided with any IMPORTANCE The proportion of daily wearers of eyeglasses among patients with coronavirus disease 2019 (COVID-19) is small, and the association between daily wear of eyeglasses and COVID-19 susceptibility has not been reported.OBJECTIVE To study the association between the daily wearing of eyeglasses and the susceptibility to COVID-19. DESIGN, SETTING, AND PARTICIPANTSThis cohort study enrolled all inpatients with COVID-19 in Suizhou Zengdu Hospital, Suizhou, China, a designated hospital for COVID-19 treatment in the area, from January 27 to March 13, 2020. COVID-19 was diagnosed according to the fifth edition of Chinese COVID-19 diagnostic guidelines. The proportion of persons with myopia who wore eyeglasses in Hubei province was based on data from a previous study.EXPOSURES Daily wearing of eyeglasses for more than 8 hours. MAIN OUTCOMES AND MEASURESThe main outcomes were the proportions of daily wearers of eyeglasses among patients admitted to the hospital with COVID-19 and among the local population. Data on exposure history, clinical symptoms, underlying diseases, duration of wearing glasses, and myopia status and the proportion of people with myopia who wore eyeglasses in Hubei province were collected. People who wore glasses for more than 8 hours a day were defined as long-term wearers.RESULTS A total of 276 patients with COVID-19 were enrolled. Of these, 155 (56.2%) were male, and the median age was 51 (interquartile range, 41-58) years. All those who wore glasses for more than 8 hours a day had myopia and included 16 of 276 patients (5.8%; 95% CI, 3.04%-8.55%). The proportion of people with myopia in Hubei province, based on a previous study, was 31.5%, which was much higher than the proportion of patients with COVID-19 who had myopia in this sample. CONCLUSIONS AND RELEVANCEIn this ...