PM2.5 is a kind of data with strong time-series characteristics, so the current PM2.5 prediction methods mostly choose RNN, LSTM and other sequence models for prediction, but because RNN, LSTM and ...other models use the same weight to calculate the data input at different times, which does not conform to the brain-like design, resulting in a low accuracy of PM2.5 concentration prediction. In view of the above problems, a PM2.5 prediction method based on attention mechanism (at-rnn and at-lstm) is proposed. This method firstly establishes the encoder-decoder model based on deep learning. In the Encoder stage, attention mechanism is added, and attention weight is allocated to the input with time series characteristics, and then Decoder analysis and prediction are carried out. Through experiments, the effects of RNN, LSTM, at-rnn and at-lstm on the prediction of PM2.5 concentration in hefei are compared. The results show that the accuracy of the prediction method based on attention model is better than other methods, indicating the effectiveness of the prediction method based on attention model in the prediction of pollutants.
•A mPCR that can simultaneously detect six common HAB-forming microalgal species was developed.•The mPCR conditions were optimized.•The developed mPCR is specific.•Background DNA did not affect the ...mPCR performance.•The mPCR is competent for convenient and accurate analysis of field samples.
Harmful algal blooms (HABs) have adverse effects on the marine ecological environment, public health, and marine economy. Thus, methods for the accurate and rapid identification of harmful algal species are urgently needed for the effective monitoring of the occurrence of HABS. A method for the parallel detection of harmful algal species must be established because various HAB-forming algal species coexist in the marine environment. This work developed a multiplex PCR (mPCR) method that can simultaneously detect six common HAB-forming microalgal species distributed along the coast of China: Karlodinium veneficum (Kv), Chattonella marina (Cm), Skeletonema spp., Scrippsiella trochoidea (St), Karenia mikimotoi (Km), and Prorocentrum donghaiense (Pd). Specific mPCR primers were designed from the internal transcribed spacer rDNA or large subunit rDNA gene of the target algal species. The mPCR conditions were optimized. Each mPCR primer was subjected to a cross-reactivity test with other microalgae to confirm the specificity of the developed mPCR system. The results of the system stability test indicated that the background concentration of DNA tested did not affect the performance of the established mPCR system. The results of the sensitivity test showed that the detection limit of the proposed mPCR system for Kv, Cm, Km, and Pd was 0.6 ng μL−1 and that for Skeletonema spp. and St was 0.06 ng μL−1. Additional mPCR analysis with spiked field samples revealed that the detection limit of the mPCR system for Km, Pd, and Kv was 60 cells, whereas that for Cm, Skeletonema spp., and St was 6 cells. The convenience and accuracy of the established mPCR assay were further validated through tests with field samples. The proposed mPCR assay is characterized by parallel analysis, strong specificity, and stability and can be used to supplement morphology-based detection methods for algal species.
Frequent outbreaks of toxic algal blooms devastate marine ecosystems, marine fisheries, and public health. Monitoring toxic algae is crucial to reduce losses caused by imminent algal blooms. However, ...traditional detection techniques relying on morphological examination are tedious and time-consuming. Therefore, the development of convenient strategies to detect toxin-producing microalgae is necessary. In this study, a novel method for the rapid, sensitive detection of Amphidinium carterae by loop-mediated isothermal amplification (LAMP) combined with a chromatographic lateral-flow dipstick (LFD) was established. The partial internal transcribed spacer gene was PCR amplified, cloned, and sequenced to design four LAMP primers and a detection probe for A. carterae detection. The LAMP detection conditions were optimized, and the optimum parameters were determined to be the following: dNTP concentration, 1.2 mM; betaine concentration, 1.2 M; magnesium ion concentration, 8 mM; ratio of inner primer to outer primer, 8:1; amplification temperature, 59 °C; and amplification time, 60 min. The specificity of LAMP-LFD was confirmed by cross-reactivity tests with other algal species. LAMP-LFD was 100 times more sensitive than regular PCR and similarly sensitive as LAMP and SYBR Green I. LAMP-LFD can be completed within 70 min and did not require special detection equipment. The convenience of the established LAMP-LFD assay was further validated by tests with simulated field-water samples. In conclusion, the developed LAMP-LFD assay can be used as a reliable and simple method of detecting A. carterae.
•The ITS of Amphidinium carterae were sequenced to design primers and probe.•The LAMP-LFD assay was developed for the detection of A. carterae.•The developed LAMP-LFD was confirmed to be specific for A. carterae.•The sensitivity of LAMP-LFD was 100-fold higher than conventional PCR.•The optimized detection protocol could be completed within 70 min.
A pentanuclear {Cr2Gd3} cluster has been successfully synthesized, which exhibits dominant ferromagnetic interactions and a considerable large −ΔSm of 27.0 J kg−1 K−1 among 3d-4f clusters.
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•A triangle bipyramid-{Cr2Gd3} based on pivalic acid is synthesized and characterized.•Complex 1 exhibits dominant ferromagnetic interactions between CrIII and GdIII ions.•Complex 1 displays a considerable large magnetic entropy value of 27.0 J kg−1 K−1 among low-nuclearity 3d-4f clusters.
A pentanuclear {Cr2Gd3} cluster (1) and its diamagnetic substituent-{Al2Gd3} (2) based on pivalic acid (Hpiv) were obtained with the formulas of {Et3NHM2Gd3(OH)6(piv)10(H2O)2} (M = CrIII, 1; AlIII, 2). The metallic core shows a triangle bipyramid-{Cr2Gd3} held together by six µ3-OH groups, and the piv- ligands located at the periphery. Magnetic studies for complex 1 exhibit dominant ferromagnetic interactions between CrIII and GdIII ions. Furthermore, ferromagnetic {Cr2Gd3} cluster (1) displays a considerable large magnetic entropy value (−ΔSm = 27.0 J kg−1 K−1) at high temperature among low-nuclearity 3d-4f clusters.
Abstract
Receptor recognition and subsequent membrane fusion are essential for the establishment of successful infection by SARS-CoV-2. Halting these steps can cure COVID-19. Here we have identified ...and characterized a potent human monoclonal antibody, HB27, that blocks SARS-CoV-2 attachment to its cellular receptor at sub-nM concentrations. Remarkably, HB27 can also prevent SARS-CoV-2 membrane fusion. Consequently, a single dose of HB27 conferred effective protection against SARS-CoV-2 in two established mouse models. Rhesus macaques showed no obvious adverse events when administrated with 10 times the effective dose of HB27. Cryo-EM studies on complex of SARS-CoV-2 trimeric S with HB27 Fab reveal that three Fab fragments work synergistically to occlude SARS-CoV-2 from binding to the ACE2 receptor. Binding of the antibody also restrains any further conformational changes of the receptor binding domain, possibly interfering with progression from the prefusion to the postfusion stage. These results suggest that HB27 is a promising candidate for immuno-therapies against COVID-19.
A novel mesoporous material covalently bonded with 8-hydroxyquinoline (HQ) was synthesized (designated as Q−SBA-15). The 5-formyl-8-hydroxyquinoline grafted to (3-aminopropyl)triethoxysilane, that ...is, alkoxysilane modified 8-hydroxyquinoline (Q-Si), was used as one of the precursors for the preparation of the Q−SBA-15 material. On the basis of the other function of the Q-Si of coordinating to lanthanide (Ln) ions, for the first time, the LnQ3 complexes (Ln = Er, Nd, Yb) have been covalently bonded to the SBA-15 materials. The derivative materials, denoted as LnQ3−SBA-15, were characterized by field emission scanning electron microscopy (FE-SEM), powder X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen adsorption–desorption, and fluorescence spectra. Upon excitation at the ligands absorption bands, all of these materials show the characteristic near-infrared (NIR) luminescence of the corresponding lanthanide ions through the intramolecular energy transfer from the ligands to the lanthanide ions. The NIR luminescence of these mesoporous materials was compared with that of the corresponding pure LnQ3 complexes and discussed in detail.
The measurement method for the LA wall thickness (WT) using cardiac computed tomography (CT) is observer dependent and cannot provide a rapid and comprehensive visualisation of the global LA WT. We ...aim to develop a LA wall-mapping application to display the global LA WT on a coplanar plane. The accuracy, intra-observer, and inter-observer reproducibility of the application were validated using digital/physical phantoms, and CT images of eight patients. This application on CT-based LA WT measures were further validated by testing six pig cardiac specimens. To evaluate its accuracy, the expanded maps of the physical phantom and pig LA were generated from the CT images and compared with the expanded map of the digital phantom and LA wall of pig heart. No significant differences (p > 0.05) were found between physical phantom and digital phantom as well as pig heart specimen and CT images using our application. Moreover, the analysis was based on the LA physical phantom or images of clinical patients; the results consistently demonstrated high intra-observer reproducibility (ICC > 0.9) and inter-observer reproducibility (ICC > 0.8) and showed good correlation between measures of pig heart specimen and CT data (r = 0.96, p < 0.001). The application can process and analyse the LA architecture for further visualisation and quantification.
The near-infrared (NIR) luminescent lanthanide ions, such as Er(III), Nd(III), and Yb(III), have been paid much attention for the potential use in the optical communications or laser systems. For the ...first time, the NIR-luminescent Ln(dbm)3phen complexes have been covalently bonded to the ordered mesoporous materials MCM-41 and SBA-15 via a functionalized phen group phen−Si (phen−Si = 5-(N,N-bis-3-(triethoxysilyl)propyl)ureyl-1,10-phenanthroline; dbm = dibenzoylmethanate; Ln = Er, Nd, Yb). The synthesis parameters X = 12 and Y = 6 h (X denotes Ln(dbm)3(H2O)2/phen−MCM-41 molar ratio or Ln(dbm)3(H2O)2/phen−SBA-15 molar ratio and Y is the reaction time for the ligand exchange reaction; phen−MCM-41 and phen−SBA-15 are phen-functionalized MCM-41 and SBA-15 mesoporous materials, respectively) were selected through a systematic and comparative study. The derivative materials, denoted as Ln(dbm)3phen−MCM-41 and Ln(dbm)3phen−SBA-15 (Ln = Er, Nd, Yb), were characterized by powder X-ray diffraction, nitrogen adsorption/desorption, Fourier transform infrared (FT-IR), elemental analysis, and fluorescence spectra. Upon excitation of the ligands absorption bands, all these materials show the characteristic NIR luminescence of the corresponding lanthanide ions through the intramolecular energy transfer from the ligands to the lanthanide ions. The excellent NIR-luminescent properties enable these mesoporous materials to have potential uses in optical amplifiers (operating at 1.3 or 1.5 μm), laser systems, or medical diagnostics. In addition, the Ln(dbm)3phen−SBA-15 materials show an overall increase in relative luminescent intensity and lifetime compared to the Ln(dbm)3phen−MCM-41 materials, which was explained by the comparison of the lanthanide ion content and the pore structures of the two kinds of mesoporous materials in detail.
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