Search

Objective To compare the immobilization effect of 2 kinds of hydrophilic magnetic beads with Ni2+-nitrilotriacetic acid (Ni2+-NTA) group or carboxyl group and surface modified by ampholytic ions on Mycobacterium tuberculosis peptide deformylase (MtPDF), and to determine the target enzyme immobilization scheme appliable to screening MtPDF ligand mixture library using magnetic separation combined with high performance liquid chromatography-mass spectrometry (HPLC-MS). Methods The plasmids pET-28a(+): def with N-terminal 6×His tagged MtPDF was successfully constructed and transfected into E.coli BL21(DE3) for MtPDF recombinant expression. The products were collected and purified using nickel-ion chelating affinity chromatography column, and then identified with the enzymatic properties. Then the obtained MtPDF was coupled to magnetic beads with Ni2+-NTA (MtPDF-Ni2+-NTA) or carboxyl group (MtPDF-carboxy), respectively. The immobilization capacity, enzyme activity, enzyme stability before and after immobilization, and the response to the inhibitor actinonin were compared between the 2 schemes. Results The immobilization capacity of MtPDF-Ni2+-NTA was 99.7±4.5 mg/g (n=3). When the ratio of amount of enzyme to magnetic beads was 1 ∶15, the retention activity of the immobilized MtPDF was (107.2±13.9)% (n=3) of the free enzyme, and decreased to 43% after 3 h under shaking at 0 ℃ and pH value of 7.5. By contrast, the immobilization capacity of MtPDF-carboxy was 36.9±2.6 mg/g (n=3), and the retention activity of the immobilized MtPDF reached to (102.6±15.4)% (n=3) when the ratio of amount of enzyme to magnetic beads was 1 ∶60, consistent with that on the Ni2+-NTA magnetic beads, with negligible changes within 8 h under shaking at 0 ℃ and pH 7.5. The response of MtPDF-carboxy to the inhibition of actinonin had no significant difference from that of free MtPDF (P>0.05). Conclusion MtPDF-carboxy magnetic beads present stable retention activity, and has similar inhibitory response as that of free MtPDF, and thus is more suitable for screening of mixture library to discover high affinity ligands for MtPDF.

This document is a correction notice for an article titled "Preclinical studies of Flonoltinib Maleate, a novel JAK2/FLT3 inhibitor, in treatment of JAK2V617F-induced myeloproliferative neoplasms" published in the Blood Cancer Journal. The correction addresses errors in Figures 4G and 7A of the article. The authors acknowledge the mistakes and state that these corrections do not affect the study's conclusions. The article provides preclinical data on the efficacy of Flonoltinib Maleate in treating myeloproliferative neoplasms. [Extracted from the article]

In this study, VO2/V2O5 heterostructures were successfully prepared by a hydrothermal and in-situ sintering procedure and were studied as aqueous zinc ion batteries (AZIBs). The novel heterostructure plays a critical role in controlling electrochemical performance. X‒ray diffraction analysis showed that the heterostructures were composed mainly of the orthorhombic VO2 and monoclinic V2O5 phases. Compared with pristine VO2 and V2O5, the VO2/V2O5 heterostructure showed excellent electrochemical properties when applied as a cathode for AZIBs. The cathode materials showed a high specific capacity of 453.6 mA h g−1 at 0.2 A g−1, considerable rate performance and capacity retention of 85.6% after 800 cycles at a scan rate of 1 A g−1. The X‒ray photoelectron spectra indicated the chemical components and elemental valence and the impedance analysis indicated the charge transfer kinetics. The method proposed herein provides a strategy for designing AZIBs with high capacity and fast ion diffusion rate. [ABSTRACT FROM AUTHOR]

Due to the increasing demand for higher security and low-cost energy storage systems, the main research focus has been developing a suitable substitute for lithium-ion batteries. Aqueous zinc ion batteries (AZIBs) are considered the best alternative to lithium-ion batteries in large-scale energy storage devices. Owing to its high capacity, vanadate is a promising cathode material for AZIBs. The crystallographic orientation of cathode materials dramatically influences the rate performance and cycling life. Here, Mg0.57V5O12·2.3H2O (MgVO) with favorable (001) crystal orientation and significantly improved electrochemical performance is prepared by a simple stirring method. The crystal growth orientations of MgVO are altered by adjusting the aging time of the reactant solution. The (001)-orientated grain growth of MgVO delivers a 232.5 mA h g−1 capacity at 5 A g−1 with a 94% capacity retention rate after 1400 cycles. The zinc ion storage performance of MgVO demonstrates that the orientation-controlled method can design effective cathode materials for high-performance ZIBs. [ABSTRACT FROM AUTHOR]

As one of the representative vanadium-based electrode materials for aqueous zinc ion batteries (AZIBs), VO2(B) owns excellent cycling stability and specific capacity, but the strong interlattice interactions lead to poor rate performance. Herein, multiphase, high ion diffusion rate Mg2VO4/VO2 (MVO/VO) heterostructures composed of nanoparticles were introduced and constructed based on a solid preinsertion method. The electrochemical results show that the MVO/VO electrode has excellent cycling stability and impressively high capacity and ion diffusion rate compared with pure VO2(B) (VO) and Mg2VO4 (MVO). Moreover, the reversible capacity of MVO/VO is found to be 393.6 mA h g–1 at a relatively low current density (0.3 A g–1). The MVO/VO electrode still exhibits a capacity retention of 83.6% even after 1000 charge/discharge applications, which indicates a stable performance. Finally, this contribution offers insights into the design of high-capacity and high ion diffusion rate AZIB cathode materials. [ABSTRACT FROM AUTHOR]

Intermountain basins are the granaries of the karst mountains of southwest China. Revealing the process and trend of land-use transformation in typical mountainous "granaries" is of great significance to optimizing land-use, food security, and rural revitalization in the karst mountains of southwest China. Lianjiang basin in Huishui County is the largest in Guizhou Province of southwest China, and a typical mountainous "granary" is used as a case study area. Based on seven periods of high-definition remote sensing images from 1966 to 2020 and on-the-spot investigation, we adopt the analysis methods of landscape pattern, moving window, and buffer zone and conduct an in-depth study on the spatial evolution of land-use and the land-use transformation law of the typical "granaries" of karst mountainous areas in southwest China from the perspectives of changes in the quantity of land-use, changes in the types of land-use, and changes in the landscape pattern. The results showed that the transformation of land-use in the basin was mainly manifested in the transformation of the function of cultivated land and the diversification of the function of cultivated land. The landscape pattern of the basin was gradually transformed from traditional rural landscape to modern agricultural landscape. The gradient effect of land-use evolution and transformation in the study basin was obvious. Traffic, location, and land resources significantly affect land-use transformation in the basin. Based on the above analysis, this paper proposes that the "granary" basins in karst mountainous areas should optimize the land-use of the basin by the trade-off between regional socio-economic development, ecological protection, and food security. The results of this paper provide a reference for land-use optimization and rural development in the granary-type basins and other similar areas in the karst mountains of southwest China. [ABSTRACT FROM AUTHOR]

Vanadium sulfide is considered one of the candidates for negative electrode materials in lithium-ion batteries (LIBs). Due to its unique layered structure and high theoretical capacity, it has received great attention from researchers. However, the cyclic life and rate performance caused by large volume changes are not ideal, which hinders its commercial application. Here, electrospun TiO2/V3S4/carbon nanotube (CNT) composite nanofibers were synthesized as anodes and showed excellent lithium storage properties. Adding carbon nanotubes can improve the overall conductivity and mechanical properties of the electrode materials. The carbon matrix doped with N and S provides more defects and active sites, which can further improve the conductivity and lithium storage capacity of the material. At a current density of 0.1 A g–1, the specific capacity of TiO2/V3S4/CNT was still 718.1 mA h g–1 after 100 cycles, and the capacity retention rate was 92.96% after removing the irreversible reaction of the first cycle. Long cycle testing was conducted at a current density of 1 A g–1, and after 700 cycles, there was still 712.2 mA h g–1. [ABSTRACT FROM AUTHOR]

Determining the soil source is crucial for agricultural planning, forensic case analysis, and archaeological site research. This study used laser induced breakdown spectroscopy (LIBS) technology combined with convolutional neural network (CNN) algorithm to determine the soil source. The experiment collected ten soil samples from different regions and extracted soil spectrum data using LIBS technology. In this study, CNN and random forest (RF) algorithms are used to analyze the data. To improve the accuracy of the model, the mean decrease accuracy (MDA) and mean decrease impurity (MDI) feature selection methods of RF are used to filter the data. Four models were constructed using CNN and RF: MDA-CNN, MDA-RF, MDI-CNN, and MDI-RF, and applied to predict soil sources. The experimental results revealed that the MDA-CNN model performs the best with the accuracy of 94.61%, precision rate of 0.9512, recall rate of 0.9461, and F1 score of 0.9487. The experimental results indicate that this analysis method can effectively determine the soil source, which holds significant implications for the development of soil source determination technology. [ABSTRACT FROM AUTHOR]