Chiral chromophores and their ordered assemblies are intriguing for yielding circularly polarized luminescence (CPL) and exploring intrinsic structure–light emission relationships. With the ...extensively studied chiral organic molecules and inorganic nanoparticle assemblies for the amplified CPL, the assemblies of copper halide hybrid clusters have attracted intensive attention due to their potential efficient CPL. Here, we report robust chiral phosphine–copper iodide hybrid clusters and their layered assemblies in crystalline states for amplified CPL. We reveal that the intermolecular interactions endow the clusters with the capability of assembling into chiral crystalline CPL materials, including hexagonal platelet-shaped microcrystals (g lum ≈ 9.5 × 10–3) and highly oriented crystalline films (g lum ≈ 5 × 10–3). Owing to the high crystalline feature of the thin film, we demonstrate an electroluminescent device with bright electroluminescence (1200 cd m–2).
Hierarchically structured chiral luminescent materials hold promise for achieving efficient circularly polarized luminescence. However, a feasible chemical route to fabricate hierarchically ...structured chiral luminescent polycrystals is still elusive because of their complex structures and complicated formation process. We here report a biomimetic non-classical crystallization (BNCC) strategy for preparing efficient hierarchically structured chiral luminescent polycrystals using well-designed highly luminescent homochiral copper(I)-iodide hybrid clusters as basic units for non-classical crystallization. By monitoring the crystallization process, we unravel the BNCC mechanism, which involves crystal nucleation, nanoparticles aggregation, oriented attachment, and mesoscopic transformation processes. We finally obtain the circularly polarized phosphors with both high luminescent efficiency of 32% and high luminescent dissymmetry factor of 1.5 × 10
, achieving the demonstration of a circularly polarized phosphor converted light emitting diode with a polarization degree of 1.84% at room temperature. Our designed BNCC strategy provides a simple, reliable, and large-scale synthetic route for preparing bright circularly polarized phosphors.
Blockade of the protein–protein interaction between the transmembrane protein programmed cell death protein 1 (PD‐1) and its ligand PD‐L1 has emerged as a promising immunotherapy for treating ...cancers. Using the technology of mirror‐image phage display, we developed the first hydrolysis‐resistant D‐peptide antagonists to target the PD‐1/PD‐L1 pathway. The optimized compound DPPA‐1 could bind PD‐L1 at an affinity of 0.51 μM in vitro. A blockade assay at the cellular level and tumor‐bearing mice experiments indicated that DPPA‐1 could also effectively disrupt the PD‐1/PD‐L1 interaction in vivo. Thus D‐peptide antagonists may provide novel low‐molecular‐weight drug candidates for cancer immunotherapy.
Protein chemical synthesis and mirror‐image phage display were combined to develop a proteolysis‐resistant D‐peptide antagonist (DPPA‐1) which targets the immune checkpoint protein PD‐L1 (the ligand for PD‐1, the programmed cell death protein 1). DPPA‐1 was found to inhibit the PD‐1/PD‐L1 protein–protein interaction at the cellular level. IgV=immunoglobulin‐like variable.
SMC (structural maintenance of chromosomes) complexes share conserved architectures and function in chromosome maintenance via an unknown mechanism. Here we have used single-molecule techniques to ...study MukBEF, the SMC complex in Escherichia coli. Real-time movies show MukB alone can compact DNA and ATP inhibits DNA compaction by MukB. We observed that DNA unidirectionally slides through MukB, potentially by a ratchet mechanism, and the sliding speed depends on the elastic energy stored in the DNA. MukE, MukF and ATP binding stabilize MukB and DNA interaction, and ATP hydrolysis regulates the loading/unloading of MukBEF from DNA. Our data suggests a new model for how MukBEF organizes the bacterial chromosome in vivo; and this model will be relevant for other SMC proteins.
•ATP-independent DNA compaction by MukB.•DNA unidirectionally slides through MukB, potentially by a ratchet mechanism.•MukE, MukF and ATP binding stabilize MukB and DNA interaction.•DNA sliding via ratchet driven by entropic force model for chromosome organization by SMC complex.
The introduction of metal–organic framework materials into photocatalysts is considered to be an effective strategy for improving the transfer and separation efficiency of photogenerated ...electron–hole pairs. In the present study, we demonstrate the delicate construction of NH2-UiO-66/ZnIn2S4 (NU66/ZIS) composites as bifunctional photocatalysts with the degradation efficiency of malachite green (98%) and the hydrogen evolution rate of a 10% NU66/ZIS composite reaching up to 2199 μmol h–1 g–1. The characterization of unique ZIS/NU66 shows that it can efficiently facilitate the separation and transfer of light-induced charges and exposed rich active sites for photocatalyst redox reaction. Moreover, the results of vitro cytotoxicity assay suggest that NU66/ZIS composites are potential safety photocatalysts to the environment and human beings. Furthermore, the DFT calculation indicates that the Zr site of NU66 and In site of ZnIn2S4 interface should be the main active center in NU66/ZIS heterojunctions.
Two transition metal complexes {Co
2
(bpda)
4
(H
2
O)
2
·4H
2
O}
n
(Co-
1
) and {Ni(bpda)
2
(H
2
O)
2
·2H
2
O}(Ni-
2
) (H
2
bpda = 2,2′-bipyridine-4,4′-dicarboxylic acid) have been synthesized by a ...hydrothermal method and characterized. These two compounds can be explored as stable electrocatalysts in the hydrogen evolution reaction (HER) using two important parameters: the overpotential and Tafel slope (TS). Electrochemical studies suggest that the reaction kinetics of a Co-
1
catalyst is more favorable than that of a Ni-
2
catalyst. Co-
1
exhibits better HER performance with an overpotential of 182 mV at a current density of 10 mA cm
−2
, a small TS of 87.21 mV dec
−1
and superior long-term durability (of up to 3000 cycles). Structural analysis shows that its catalytic activity is improved due to the two mixed valence cobalt ions and the pore structure formed by hydrogen bonds in Co-
1
, which is different from that of Ni-
2
. In addition, the mechanism of the HER is also explained theoretically by DFT molecular orbital and free energy calculations in this article.
Co-
1
exhibits a three-dimensional pore structure through hydrogen bonding and π-conjugation, providing a platform for efficient charge carrier mobility and the hydrogen evolution reaction.
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•CN-SA was designed by thermal copolymerization of urea and salicylic acid.•A distorted and porous structure of CN-SA sample may offer more active sites for the ...pollutants.•Enhancement of charge carrier separation efficiency and a narrowed band gap are obtained by modification.•CN-SA sample exhibited much enhanced photocatalytic activity for TC and SMZ degradation.
Photocatalysis has been widely studied as a promising technique for removal of organic pollutants in wastewater. A modified carbon nitride has been designed for this purpose. In this study, a facile method to synthesize distorted carbon nitride by simply copolymerizing urea and salicylic acid (SA) has been explored. The incorporation of SA induced the structure change from planar structure to distorted curls structure. Compared to pristine CN, the CN-SA shows wide light absorption, which is attributed to the n → π* transition at the nitrogen atoms with lone pair electrons of heptazine units. The photoelectrode of CN-SA exhibited higher photocurrent and lower charge resistance than that of pristine CN electrode, indicating that the photogenerated charge carriers of CN-SA are more efficiently separated. As a result, the optimal CN-SA shows 2-fold enhancement in degradation of tetracycline (TC) as compared to pristine CN. Furthermore, we found that the degradation rate of sulfamethazine (SMZ) was 0.0823 min−1 using the CN-SA photocatalyst, which is three times higher than that of pristine CN (0.0293 min−1). In addition, the CN-SA shows good stability without structural change or loss of photocatalytic performance after four cycles. According to the radical species trapping experiments and electron spin resonance analyses, O2− and h+ were the main active species involved in the degradation of organic pollutants. The developed strategy provides a novel approach to design the tunable band structure of organic semiconductor materials for various applications.
An effective security strategy for Wireless Sensor Networks (WSNs) is imperative to counteract security threats. Meanwhile, energy consumption directly affects the network lifetime of a wireless ...sensor. Thus, an attempt to exploit a low-consumption Intrusion Detection System (IDS) to detect malicious attacks makes a lot of sense. Existing Intrusion Detection Systems can only detect specific attacks and their network lifetime is short due to their high energy consumption. For the purpose of reducing energy consumption and ensuring high efficiency, this paper proposes an intrusion detection model based on game theory and an autoregressive model. The paper not only improves the autoregressive theory model into a non-cooperative, complete-information, static game model, but also predicts attack pattern reliably. The proposed approach improves on previous approaches in two main ways: (1) it takes energy consumption of the intrusion detection process into account, and (2) it obtains the optimal defense strategy that balances the system’s detection efficiency and energy consumption by analyzing the model’s mixed Nash equilibrium solution. In the simulation experiment, the running time of the process is regarded as the main indicator of energy consumption of the system. The simulation results show that our proposed IDS not only effectively predicts the attack time and the next targeted cluster based on the game theory, but also reduces energy consumption.
The long-term pulmonary function and related physiological characteristics of COVID-19 survivors have not been studied in depth, thus many aspects are not understood.
COVID-19 survivors were ...recruited for high resolution computed tomography (HRCT) of the thorax, lung function and serum levels of SARS-CoV-2 IgG antibody tests 3 months after discharge. The relationship between the clinical characteristics and the pulmonary function or CT scores were investigated.
Fifty-five recovered patients participated in this study. SARS-CoV-2 infection related symptoms were detected in 35 of them and different degrees of radiological abnormalities were detected in 39 patients. Urea nitrogen concentration at admission was associated with the presence of CT abnormalities (P = 0.046, OR 7.149, 95% CI 1.038 to 49.216). Lung function abnormalities were detected in 14 patients and the measurement of D-dimer levels at admission may be useful for prediction of impaired diffusion defect (P = 0.031, OR 1.066, 95% CI 1.006 to 1.129). Of all the subjects, 47 of 55 patients tested positive for SARS-CoV-2 IgG in serum, among which the generation of Immunoglobulin G (IgG) antibody in female patients was stronger than male patients in infection rehabilitation phase.
Radiological and physiological abnormalities were still found in a considerable proportion of COVID-19 survivors without critical cases 3 months after discharge. Higher level of D-dimer on admission could effectively predict impaired DLCO after 3 months discharge. It is necessary to follow up the COVID-19 patients to appropriately manage any persistent or emerging long-term sequelae.
Key Scientific Research Projects of Henan Higher Education Institutions
Increasing grain production is essential to those areas where food is scarce. Increasing grain production by controlling crop diseases and pests in time should be effective. To construct video ...detection system for plant diseases and pests, and to build a real-time crop diseases and pests video detection system in the future, a deep learning-based video detection architecture with a custom backbone was proposed for detecting plant diseases and pests in videos. We first transformed the video into still frame, then sent the frame to the still-image detector for detection, and finally synthesized the frames into video. In the still-image detector, we used faster-RCNN as the framework. We used image-training models to detect relatively blurry videos. Additionally, a set of video-based evaluation metrics based on a machine learning classifier was proposed, which reflected the quality of video detection effectively in the experiments. Experiments showed that our system with the custom backbone was more suitable for detection of the untrained rice videos than VGG16, ResNet-50, ResNet-101 backbone system and YOLOv3 with our experimental environment.
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