Background TH 2 cells play a critical role in the pathogenesis of allergic asthma. Established TH 2 cells have been shown to resist reprogramming into TH 1 cells. The inherent stability of TH 2 cells ...poses a significant barrier to treating allergic diseases. Objective We sought to understand the mechanisms by which CD4+ T cells from asthmatic patients resist the IL-27–mediated inhibition. Methods We isolated and cultured CD4+ T cells from both healthy subjects and allergic asthmatic patients to test whether IL-27 can inhibit IL-4 production by the cultured CD4+ T cells using ELISA. Culturing conditions that resulted in resistance to IL-27 were determined by using both murine and human CD4+ T-cell culture systems. Signal transducer and activator of transcription (STAT) 1 phosphorylation was analyzed by means of Western blotting and flow cytometry. Suppressor of cytokine signaling ( Socs ) mRNA expression was measured by using quantitative PCR. The small interfering RNA method was used to knockdown the expression of Socs3 mRNA. Results We demonstrated that CD4+ T cells from asthmatic patients resisted the suppression of IL-4 production mediated by IL-27. We observed that repeated exposure to TH 2-inducing conditions rendered healthy human CD4+ T cells resistant to IL-27–mediated inhibition. Using an in vitro murine culture system, we further demonstrated that repeated or higher doses of IL-4 stimulation, but not IL-2 stimulation, upregulated Socs3 mRNA expression and impaired IL-27–induced STAT1 phosphorylation. The knockdown of Socs3 mRNA expression restored IL-27–induced STAT1 phosphorylation and IL-27–mediated inhibition of IL-4 production. Conclusions Our findings demonstrate that differentiated TH 2 cells can resist IL-27–induced reprogramming toward TH 1 cells by downregulating STAT1 phosphorylation and likely explain why the CD4+ T cells of asthmatic patients are resistant to IL-27–mediated inhibition.
In recent decades, great expectation has always been placed on catalysts that can convert toxic CO into CO2 under mild conditions. The catalytic mechanism of CO oxidation by Mn-coordinated N-doped ...graphene with a single vacancy (MnN3-SV) and a double vacancy (MnN3-DV) was studied by density functional theory (DFT) calculations. Molecular dynamics simulations showed that CO2 on MnN3-SV could not be desorbed from the substrate and MnN3-SV was not suitable for use as a CO oxidation catalyst. MnN3-DV was more suitable for CO oxidation (COOR) and from the electronic structure it was found that the Mn atom was the main active site, which was the reaction site for CO oxidation. At temperatures of 0 and 298.15 K, CO oxidation on MnN3-DV via the Langmuir–Hinshelwood (LH) mechanism was the best reaction pathway. The rate-determining step using MnN3-DV as the catalyst for CO oxidation through the LH mechanism was O2 + CO → OOCO, and the energy barrier was 0.861 eV at 298.15 K. MnN3-DV was suitable as a catalyst for CO oxidation in terms of both thermodynamics and kinetics. This study provides a comprehensive understanding of the various reaction mechanisms of CO oxidation on MnN3-DV, which is conducive to guiding the development and design of efficient catalysts for CO oxidation.
After the outbreak of COVID-19, the interaction of infectious disease systems and social systems has challenged traditional infectious disease modeling methods. Starting from the research purpose and ...data, researchers improved the structure and data of the compartment model or used agents and artificial intelligence based models to solve epidemiological problems. In terms of modeling methods, the researchers use compartment subdivision, dynamic parameters, agent-based model methods, and artificial intelligence related methods. In terms of factors studied, the researchers studied 6 categories: human mobility, nonpharmaceutical interventions (NPIs), ages, medical resources, human response, and vaccine. The researchers completed the study of factors through modeling methods to quantitatively analyze the impact of social systems and put forward their suggestions for the future transmission status of infectious diseases and prevention and control strategies. This review started with a research structure of research purpose, factor, data, model, and conclusion. Focusing on the post-COVID-19 infectious disease prediction simulation research, this study summarized various improvement methods and analyzes matching improvements for various specific research purposes.
Bacterial infection tendentiously triggers inflammasome activation, whereas the roles of inflammasome activation in host defense against diverse infections remain unclear. Here, we identified that an ...ASC-dependent inflammasome activation played opposite roles in host defense against
Francisella novicida
wild-type (WT) U112 and mutant strain XWK4. Comparing with U112, XWK4 infection induced robust cytokine production, ASC-dependent inflammasome activation, and pyroptosis. Both AIM2 and NLRP3 were involved and played independent roles in XWK4-induced inflammasome activation. Type II interferon was partially required for XWK4-triggered inflammasome activation, which was different from type I interferon dependency in U112-induced inflammasome activation. Distinct from
F. novicida
U112 and
Acinetobacter baumannii
infection,
Asc
–/–
mice were more resistant than WT mice response to XWK4 infection by limiting bacterial burden
in vivo
. The excessive inflammasome activation triggered by XWK4 infection caused dramatical cell death and pathological damage. Our study offers novel insights into mechanisms of inflammasome activation in host defense and provides potential therapeutic approach against bacterial infections and inflammatory diseases.
Manganese silicides nanostructures showed great potential applications in microelectronic and optoelectronic devices. In this study, Mn4Si7 and Si–Mn4Si7 axial heterostructure nanowire arrays were ...synthesized by the in-situ reaction between Si nanowire arrays and MnCl2. Depending on the reaction durations and processes, structures (Mn4Si7 nanowires or Si–Mn4Si7 axial heterostructure nanowires) and lengths of the Mn4Si7 nanowires could be readily tuned. Phase identification were performed by the XRD, TEM, HRTEM, and SAED means, which results indicated that the as-synthesized nanowire is Nowotny chimney ladder (NCL) structure Mn4Si7 with a tetragonal structure. The Mn4Si7 nanowire arrays exhibited enhanced ferromagnetism comparing with other bulk higher manganese silicides. The Curie temperature of the Mn4Si7 nanowire arrays is over 300 K, which is much higher than that of the previous reports. Because of the good compatibility with Si-based nanowire devices and many favorable properties, these Mn4Si7 nanowire arrays have wide potential applications in the Si-based self-assembly nanowire devices.
The research of unmanned aerial vehicles’ (UAVs’) autonomy navigation and landing guidance with computer vision has important significance. However, because of the image blurring, the position of the ...cooperative points cannot be obtained accurately, and the pose estimation algorithms based on the feature points have low precision. In this research, the pose estimation algorithm of UAV is proposed based on feature lines of the cooperative object for autonomous landing. This method uses the actual shape of the cooperative-target on ground and the principle of vanishing line. Roll angle is calculated from the vanishing line. Yaw angle is calculated from the location of the target in the image. Finally, the remaining extrinsic parameters are calculated by the coordinates transformation. Experimental results show that the pose estimation algorithm based on line feature has a higher precision and is more reliable than the pose estimation algorithm based on points feature. Moreover, the error of the algorithm we proposed is small enough when the UAV is near to the landing strip, and it can meet the basic requirements of UAV’s autonomous landing.
Cell-penetrating peptides (CPP) can translocate across the cell membrane and have been extensively studied for the delivery of proteins, nucleic acids, and therapeutics in mammalian cells. However, ...characterizations of CPP in plants have only recently been initiated. We showed that the intact virion and a recombinant capsid protein (CaP) from a plant-infecting nonenveloped icosahedral RNA virus, Brome mosaic virus (BMV), can penetrate the membranes of plant protoplasts but are trapped by the extracellular matrix. Furthermore, a 22-residue peptide derived from the N-terminal region of the CaP (CPNT) can enter barley protoplasts and cells of intact barley and Arabidopsis roots. An inhibitor of the macropinocytosis reduced CPNT entry, while treatment with NiCl2 changed the cellular localization of CPNT. CPNT increased uptake of the green flourescent protein (GFP) into the cell when covalently fused to GFP or when present in trans of GFP. The BMV CPNT overlaps with the sequence known to bind BMV RNA, and it can deliver BMV RNAs into cells, resulting in viral replication, as well as deliver double-stranded RNAs that can induce gene silencing.
Exploring an efficient and pollution-free hydrogen evolution reaction (HER) electrocatalyst based on the combination of rare-earth metal and nonnoble metal is of significant importance. However, ...successfully achieving such a goal remains highly challenging. Herein, a nanosheet comprising a MoO2–CeF3 heterojunction (MoO2–CeF3/NF) is successfully prepared via a three-step method. (1) Growth of hexahedral nickel hydroxide Ni(OH)2 on a 3D nickel foam (NF) as the scaffold. (2) In situ hydrothermal growth of a precursor nanosheet structure on the scaffold. (3) Calcination treatment at 450 °C in the presence of hydrogen. Herein, the electron redistribution at the heterointerface of CeF3 and MoO2 is a contributing factor toward enhanced HER activity. Appropriate introduction of CeF3 can enlarge the size of nanosheets, increase numerous active sites, increase the catalytic durability of the material, and change electron distribution on the MoO2 interface; all of the above improve HER activity. Because of its interfacial nanosheet structure, MoO2–CeF3/NF demonstrates pre-eminent HER capability in both alkaline (1.0 M KOH) and acidic (0.5 M H2SO4) electrolytes, with extremely small overpotentials of 18 and 42 mV at 10 mA cm–2, respectively. This is obviously lower than the overpotential of Pt/C in alkaline media (27 mV), and it is also close to the overpotential of Pt/C in acidic media (41 mV), at the same current density. More importantly, MoO2–CeF3/NF displays a better HER activity than Pt/C at a current density of >112 mA cm–2 in both alkaline and acidic electrolytes. This work offers a novel strategy toward high-performance hydrogen production by designing a transition metal oxide and rare-earth metal heterojunction.
Development of a highly efficient trifunctional electrocatalyst for hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is essential in a variety of ...energy conversion technologies, such as H2-O2 fuel cell and overall water splitting. However, state-of-the-art electrocatalysts (Pt, Ir, Ru) for these electrochemical reactions suffer from high cost. Therefore, search for novel and cost-effective metal-based catalysts have gained tremendous attention. In this work, we investigated a novel Cd based electrocatalysts as efficient trifunctional electrocatalysts by density functional theory analysis. An in-depth reaction mechanism of CdN4C0-gra and CdN0C4-gra structure in acidic conditions had been investigated. After a detailed and systematic analysis by partial densities of states (PDOS) and Gibbs free energy (ΔG) of various modeled catalytic systems, the catalysts system composed of CdN4C0-gra showed excellent electrocatalytic properties with an overpotential of (ƞHER = 0.05 V, ƞOER = 0.48 V, and ƞORR = 0.75 V).
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•The catalytic mechanism of Cd–N–C-doped graphene system for OER, ORR and HER reactions were investigated for the first time.•Catalytic performance of CdN4 C0 -gra is better, when Cd is coordinated by four N atoms (Cd-N4 -C).•In the acidic conditions, water molecules influence the adsorption of OH*,and improve the catalytic performance.•The overpotentials of trifunctional electrocatalyst CdN4C0-gra (PH=0) are ƞHER = 0.05 V, ƞOER = 0.48 V and ƞORR = 0.75 V.
Exploration for an earth-rich and competent electrocatalyst for the hydrogen evolution reaction (HER) is a significant and challenging approach to confronting the resources shortage and environmental ...crisis. Porous N-doped Mo2C@C (N-Mo2C@C) nanoparticles self-encapsulated in nanospheres are presented as a high-performing HER electrocatalyst fabricated through a one-pot solvothermal method followed by hydrogen calcination. Structural analyses show that acetamide can regulate the size of the nanospheres, provide a N source for doping and form porous structures composed of Mo2C, which suggests the exposure of extensive active sites as well as the contact and diffusion among the medium, electrodes, and gas. Theoretical calculations show that the N doping can enhance the activity of the Mo-C bond, reduce the energy of capturing hydrogen intermediates, and increase the catalytic conductivity. This work offers a simple and promising strategy to understand the catalytic mechanism required to optimize the activity of Mo-based electrocatalysts via N doping.
porous N-Mo2C@C nanoparticles self-encapsulated in nanospheres with glucose as the carbon source as a high-performing HER electrocatalyst fabricated through a one-pot solvothermal method followed by appropriate hydrogen calcination N-Mo2C@C demonstrates excellent HER electrocatalytic performance and robust stability in an alkaline medium. Display omitted
•N doping can enhance the activity of the Mo-C bond.•N-Mo2C@C nanoparticles can enhance the HER intrinsic activities and stability.•Carbon layer can protect the nanoparticles from corrosion and improve conductivity.•DFT calculations confirm that N doping can reduce the H∗ adsorption energy.
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