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BACKGROUD: T follicular helper (Tfh) cells have been discovered to be the main CD4+ T cells assisting B cells to produce antibody. They are over activated in patients with systemic lupus erythematosus (SLE) and consequently lead to excessive immunity. Hematopoietic progenitor kinase 1 (HPK1) negatively regulates T cell-mediated immune responses and TCR signal. This study aimed to investigate the roles of HPK1 in SLE Tfh cells. METHODS: HPK1 mRNA and protein levels in Tfh cells were measured by real-time quantitative PCR and western blot analysis, respectively. The production of IL-21, B cell-activating factor (BAFF), interferon γ (IFNγ), IL-17A, IgM, IgG1, IgG2, and IgG3 were analyzed using enzyme linked immunosorbent assay. Tfh cells proliferation was evaluated with 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. RESULTS: HPK1 mRNA and protein levels were significantly reduced in SLE Tfh cells, and negatively correlated with SLE disease activity index (SLEDAI) and Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) Damage Index for SLE (SDI). Knocking down HPK1 with siRNA in normal Tfh cells greatly elevated Tfh cells proliferation and secretions of IL-21, BAFF, IFNγ, IgG1, IgG2, and IgG3. There were no marked alterations in IL-17A and IgM productions. The opposite effects were observed in SLE Tfh cells transfected with HPK1 overexpressing plasmid: Tfh cells proliferation and productions of IL-21, BAFF, IFNγ, IgG1, IgG2, and IgG3 were all alleviated. And there were no significant changes in IL-17A and IgM levels. CONCLUSION: Our results suggest for the first time that inhibited expression of HPK1 in SLE Tfh cells leading to Tfh cells overactivation and B cells overstimulation, subsequently, the onset and progression of SLE.
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Interleucina-17 , Lúpus Eritematoso Sistêmico , Autoimunidade , Humanos , Imunoglobulina G/genética , Imunoglobulina M/genética , Interferon gama , Lúpus Eritematoso Sistêmico/genética , Proteínas Serina-Treonina Quinases , RNA Mensageiro/genética , Células T Auxiliares Foliculares , Linfócitos T Auxiliares-IndutoresRESUMO
Rosacea is a kind of chronic inflammatory skin disease that usually occurs in the middle of the face. Diammonium glycyrrhizinate (DG), an effective monomer component extracted from licorice, has extensive anti-inflammatory, antioxidant, anti-allergic, and immunomodulatory effects. There is no research on its therapeutic effect on rosacea. In this study, we divided rosacea patients mainly characterized by papules and pustules randomly into three groups. Group A received clarithromycin 500 mg once a day, isotretinoin 10 mg once a day; Group B received DG 150 mg three times a day, other medicines were the same as Group A; Group C received clarithromycin 250 mg once a day, isotretinoin 10 mg once every 2 days, and DG 150 mg three times a day. All patients' symptom scores and laboratory tests were evaluated when followed up. We found that DG combined with clarithromycin and isotretinoin in the treatment of rosacea was more effective and quicker than clarithromycin and isotretinoin alone. Moreover, half common dosage of clarithromycin and isotretinoin combined with DG could achieve the same therapeutic effect as the conventional dose, and brought about lower incidences of adverse events (AEs). Therefore, it is recommended to use half common dosage of routine medication combined with DG for rosacea patients mainly characterized by papules and pustules.
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Exantema , Rosácea , Humanos , Isotretinoína , Ácido Glicirrízico/efeitos adversos , Claritromicina/uso terapêutico , Rosácea/diagnóstico , Rosácea/tratamento farmacológico , Método Duplo-Cego , Exantema/induzido quimicamenteRESUMO
Smokeless tobacco products provide an alternative to cigarettes; however, smokeless tobacco is carcinogenic and harmful to human health. This study evaluated the toxicological effects of snus extracts and cigarette smoke total particulate matter (TPM) on human umbilical vein endothelial cells (HUVECs). Treated cells were examined for cell viability, reactive oxygen species (ROS), apoptosis, and inflammatory cytokines. Moreover, we explored the mechanism of programmed cell death induced by snus. The results showed that snus extracts significantly inhibited cell viability in a dose-dependent manner. ROS was significantly increased in treatment groups, and anti-oxidant treatment could not prevent snus extract-induced cell death. Snus extracts induced apoptosis, DNA damage, activation and cleavage of caspase-3 and caspase-8, pathway-related gene change, and interleukin (IL)-6 and IL-8 release in HUVECs. Snus extracts exposure may induce cytotoxicity, ROS generation, inflammatory cytokines release, and apoptosis or DNA damage through intrinsic and extrinsic pathways in HUVECs.
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Células Endoteliais da Veia Umbilical Humana , Tabaco sem Fumaça , Apoptose , Sobrevivência Celular , Citocinas/genética , Humanos , Espécies Reativas de Oxigênio , Tabaco sem Fumaça/toxicidadeRESUMO
To obtain high-quality joints of Al/steel dissimilar materials, a new extrinsic-riveting friction stir lap welding (ERFSLW) method was proposed combining the synthesis advantages of mechanical riveting and metallurgical bonding. SiC-reinforced Al matrix composite bars were placed in the prefabricated holes in Al sheets and steel sheets, arranged in a zigzag array. The bars were stirred and mixed with Al sheets under severe plastic deformation (SPD), forming composite rivets to strengthen the mechanical joining. SiC particles were uniformly dispersed in the lower part of the welding nugget zone (WNZ). The smooth transition between the SiC mixed zone and extrinsic-riveting zone (ERZ) ensured the metallurgical bonding. The maximum tensile shear load of the joints reached 7.8 kN and the maximum load of the weld per unit length was 497 N/mm. The fracture occurred at the interface between the rivets and steel sheets rather than the conventional Al/steel joining interface. Moreover, ERFSLW can prolong the service life of joints due to three fracture stages. This method can be further extended to the welding of other dissimilar materials that conform to the model of "soft/hard".
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Aiming at the repairing of keyhole defects after friction stir welding of complex structures, a new method combined with tungsten inert gas welding (TIG) and friction stir processing (FSP) was proposed. The results showed that the pre-filling wire of TIG can completely fill the volumetric keyhole. FSP can refine the coarse grain area into equiaxial grains due to dynamic recrystallization, while some pore defects are eliminated. The interface bonding quality is high. The microhardness of the repairing zone with FSP is significantly stronger than that of the untreated parts. Compared to direct TIG repairing, the introduction of FSP transformed the fracture from brittle fracture to ductile fracture, and the tensile strength of the joint was increased by 131.7%, realizing the high-quality repairing of keyhole defects in 2195 Al-Li alloy.
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Friction stir welding was utilized to obtain high-quality SUS301L stainless steel joints, whose mechanical and corrosion properties were thoroughly evaluated. Sound joints were obtained with a wide range of rotational velocities from 400 to 700 rpm. The microstructures of the stir zone primarily consisted of austenite and lath martensite without the formation of detrimental phases. The ultimate tensile strength of the welded joints improved with higher rotational velocities apart from 400 rpm. The ultimate tensile strength reached 813 ± 16 MPa, equal to 98.1 ± 1.9% of the base materials (BMs) with a rotational velocity of 700 rpm. The corrosion resistance of the FSW joints was improved, and the corrosion rates related to uniform corrosion with lower rotational velocities were one order of magnitude lower than that of the BMs, which was attributed to the lower martensite content. However, better anti-pitting corrosion performance was obtained with a high rotational velocity of 700 rpm, which was inconsistent with the uniform corrosion results. It could be speculated that a higher martensitic content had a negative effect on the uniform corrosion performance, but had a positive effect on the improvement of the anti-pitting corrosion ability.
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In the quest for excellent light-structural materials that can withstand mechanical extremes for advanced applications, design and control of microstructures beyond current material design strategies have become paramount. Herein, we design a coherent shell at incoherent precipitates in the 2195 aluminum alloy with multi-step metastable phase transitions. A high local strain rate via a neoteric deformation-driven metallurgy method facilitated the diffusion of Li. The original T1 (Al2CuLi) phases were transformed into coherent-shell (Li-rich) irregular-coated incoherent-core (Al2Cu) precipitates. The ultimate tensile strength and elongation reached 620 ± 18 MPa and 22.3 ± 2.2%, exhibiting excellent strength-ductility synergy. Grain boundaries, dislocation, solid solution atoms, and precipitates all contributed to the yield strength of the materials, among which precipitates occupied a dominant position, contributing approximately 56.07%. A new "incoherent-coherent interact" strain-hardening mechanism was also clarified, which was believed to be promoted in other heat-treatable alloy systems, especially with multi-step metastable phase transitions.
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Interplanting crops is the best method to grow crops synergistically for better utilization of land and agro-resources. Grape (Vitis vinifera) and potato (Solanum tuberosum L.) have highly efficient agricultural planting systems in China, however, how soil physicochemical properties and soil microbial communities and metabolites affect the output of grape-potato interplanting remained unknown. In this study, we employed three planting patterns (CK: grape monocropping; YY: grape interplanted with potato (variety 'Favorita'); LS: grape interplanted with potato (variety 'Longshu7')) at two experimental sites i.e., the Huizhou (2022) site and the Qingyuan site (2023). The grape variety for all planting patterns was 'Sunshine Rose'. Soil samples (top 0-20 cm) at both sites were collected to observe the diversity of bacterial communities and soil metabolites. Our findings revealed that, compared with monocropping, the interplanted systems resulted in higher concentrations of total nitrogen, available phosphorus, and available potassium and enhanced the activities of acid phosphatase, urease, and protease. The potato root exudates also altered the relative abundance of Bacillus, Kaistobacter, and Streptomyces in the rhizosphere. Among the soil metabolites, lipids and organic acids showed the most significant changes. Notably, 13-L-hydroperoxylinoleic acid is the key differentially abundant metabolite involved in the regulation of linoleic acid metabolism pathways. The association analyses of the metabolome, microbiome, and soil physicochemical properties revealed that the interactions of microbes and metabolites resulted in differences in the soil nutrient content, whereas the interactions of 13-L-hydroperoxylinoleic acid and Firmicutes improved the soil nutrient levels and bacterial composition in the interplanting systems. In summary, our findings demonstrated that intercropping grapes with potato 'Favorita' was better with respect to improving soil nutrients, soil enzyme activity, the diversity of soil bacteria, and soil metabolites without causing adverse impacts on grape yield. Overall, this study explained the physiological mechanisms by which soil microorganisms and metabolites promote potato growth in grape interplanting and provided new perspectives for the utilization of soil resources in vineyards.
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The development of next-generation high-capacity freestanding materials as electrodes in lithium-ion batteries (LIBs) has significant potential. Here, oxygen vacancy-rich ZnO (Ov-ZnO) deposited on carbonized bacterial cellulose (CBC) aerogels is developed via in-situ uniformly growing ZIF-8-NH2 particles on CBC aerogels, followed by the hydrazine reduction and pyrolysis. The CBC serves as a free-standing skeleton to disperse and support ZIF-8-NH2 derived ZnO while the introduction of oxygen vacancies can effectively promote the internal ion/electron transfer. As a result, the obtained free-standing aerogels (Ov-ZnO@CBC) displays a reversible capacity of 710 mAh g-1 at 1 A g-1 after 1000 cycles, which is superior to ZnO@CBC without hydrazine reduction treatment. Furthermore, the assembled Li free-standing full cell using the Ov-ZnO@CBC composite as the anode and BC@LiFePO4 (BC@LFP) as the cathode exhibits an outstanding cycling performance of 150 mAh g-1 after 100 cycles at 0.1 A g-1, displaying satisfactory lithium-ion storage capability. It is noteworthy that both Ov-ZnO@CBC and BC@LFP are obtained in the form of a free-standing aerogel. This work offers a strategy to prepare high-capacity and long-cycle self-supporting aerogel-based electrodes for flexible LIBs.
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Zeolitic imidazolate frameworks (ZIFs) bearing rich accessible Lewis acidic/basic active sites and hierarchical pores are favorable to catalyze the cycloaddition of CO2 and epoxides with high yields of the target product under mild conditions. In this context, a facile etching and regrowth method is developed here to convert unstable leaf-like zinc-based ZIF-L to one kind of bimetallic ZIF (namely, ZnFe-ZIF) with a rough surface, a porous and accessible three-dimensional structure, and abundant Lewis acidic sites. Owing to the high Fe-doping content functioning as rich Lewis acidic sites and the high CO2 adsorbing capability together with the structural advantages to favor the mass diffusion, the yield of target cyclic carbonate can be up to >99% for the cycloaddition of CO2 and epichlorohydrin by ZnFe-ZIF at 6 h under mild conditions (0.1 MPa and 80 °C) with the selectivity of 100%. More importantly, unlike ZIF-L, which is unstable in the reaction system, the synthesized ZnFe-ZIF displays a satisfactory chemical stability without a loss in catalytic activities after five recycling runs as well as good substrate tolerance, making ZnFe-ZIF a potential high-performance catalyst for CO2 conversion.
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The metal ion etching induced transformation of zeolitic imidazolate frameworks (ZIFs) to layered double hydroxides (LDHs) is closely related to the etching conditions. Here, by tuning the Ni2+ etching conditions (e.g., initial Ni2+ concentration and etching time), Co-ZIF-L templated CoNi-LDH with diverse morphologies and tailorable compositions are obtained and their resultant electrochemical properties are optimized. Mechanism study reveals that the etching conditions significantly affect the disassembling rate of Co-ZIF-L as well as the formation rate of CoNi-LDH, leading to the morphological and compositional variance of etched samples, which further results in their distinct electrochemical activities. The resultant asymmetric supercapacitor assembled with Co-ZIF-L derived CoNi-LDH and activated carbon can achieve a maximum energy density of 77.3 Wh/kg at a power density of 700 W/kg with the capacity retention of 85.7 % after 2000 cycles, superior or comparable to other advanced CoNi-LDH based supercapacitors.
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CoS2/Co-Ni layered double hydroxides (LDHs) with a rational tailored pore structure are developed by partial sulfurization of Co-ZIF-L and subsequent Ni2+ etching for the transformation of zeolitic imidazolate frameworks (ZIFs) to layered double hydroxides. The as-synthesized CoS2/Co-Ni LDHs maintain the leaf-like structure and have rich hierarchical pores. More importantly, CoS2 nanoparticles are uniformly embedded among Co-Ni LDH layers, facilitating mass diffusion and favorably exposing more active sites. Benefiting from these desirable compositional and structural features, a remarkable specific capacitance (capacity) of 1784 F/g (223 mAh/g) at 1 A/g is delivered by CoS2/Co-Ni LDHs. Furthermore, the as-assembled CoS2/Co-Ni LDH//activated carbon as the asymmetric supercapacitor device also exhibits a high energy density of 125 Wh/kg at a power density of 800 W/kg and a superb capacitance retention of 98 % after 5000 cycles, outperforming many Co-Ni LDH based electrode materials reported in the literature.
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Endoplasmic reticulum-associated degradation (ERAD) maintains protein homeostasis by retrieving misfolded proteins from the endoplasmic reticulum (ER) lumen into the cytosol for degradation. The retrotranslocation of misfolded proteins across the ER membrane is an energy-consuming process, with the detailed transportation mechanism still needing clarification. We determined the cryo-EM structures of the hetero-decameric complex formed by the Derlin-1 tetramer and the p97 hexamer. It showed an intriguing asymmetric complex and a putative coordinated squeezing movement in Derlin-1 and p97 parts. With the conformational changes of p97 induced by its ATP hydrolysis activities, the Derlin-1 channel could be torn into a "U" shape with a large opening to the lipidic environment, thereby forming an entry for the substrates in the ER membrane. The EM analysis showed that p97 formed a functional protein complex with Derlin-1, revealing the coupling mechanism between the ERAD retrotranslocation and the ATP hydrolysis activities.
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Degradação Associada com o Retículo Endoplasmático , Complexo de Endopeptidases do Proteassoma , Humanos , Microscopia Crioeletrônica , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteínas de Membrana/metabolismo , Adenosina Trifosfatases/metabolismo , Trifosfato de Adenosina/metabolismoRESUMO
Interleukin-35 (IL-35) is a lately observed cytokine and is part of the IL-12 cytokine family. IL-35 includes two subunits, p35 and Epstein-Barr virus-induced gene 3, and activates subsequent signaling pathways by binding to receptors to mediate signal transduction, thereby modulating the immunoregulatory functions of T cells, B cells, macrophages, and other immune cell types. Although there is currently limited research on the roles of IL-35 in human autoimmunity, many studies have demonstrated that IL-35 may mediate immunosuppression. Therefore, it plays an essential role in some autoimmune dermatoses, including systemic lupus erythematosus, psoriasis, systemic sclerosis, and dermatomyositis. We will introduce the structure and biological characteristics of IL-35 and summarize its effects on the occurrence and development of autoimmune dermatoses in this article. It is suggested that IL-35 is a possible target for therapy in the aforementioned diseases.
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T follicular helper (Tfh) cells are overactivated in systemic lupus erythematosus (SLE) patients and contribute to excessive immunity. Hematopoietic progenitor kinase 1 (HPK1), as an inhibitor of T cells, is underexpressed in SLE Tfh cells and consequently induces autoimmunity. However, the reason for downregulation of HPK1 in SLE Tfh cells remains elusive. By combining chromatin immunoprecipitation with quantitative polymerase chain reaction assays, it was found that histone H3 lysine 27 trimethylation (H3K27me3) at the HPK1 promoter in SLE Tfh cells elevated greatly. We also confirmed jumonji domain-containing 3 (JMJD3) binding at the HPK1 promoter in SLE Tfh cells reduced profoundly. Knocking down JMJD3 in normal Tfh cells with siRNA alleviated enrichments of JMJD3, H3K4me3, and mixed-lineage leukemia (MLL) 1 at the HPK1 promoter and increased H3K27me3 number in the region. HPK1 expression was lowered, while Tfh cell proliferation activity, IL-21 and IFNγ secretions in the supernatants of Tfh cells, and IgG1 and IgG3 concentrations in the supernatants of Tfh-B cell cocultures all upregulated markedly. In contrast, elevating JMJD3 amount in SLE Tfh cells by JMJD3-overexpressed plasmid showed opposite effects. The abundances of H3K4me3 and MLL1 at the HPK1 promoter in SLE Tfh cells were greatly attenuated. Our results suggest that deficient JMJD3 binding at the promoter dampens HPK1 expression in SLE Tfh cells, thus making Tfh cells overactive, and ultimately results in onset of SLE.
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Histona Desmetilases com o Domínio Jumonji , Lúpus Eritematoso Sistêmico , Proteínas Serina-Treonina Quinases , Células T Auxiliares Foliculares , Regulação para Baixo , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/imunologia , Histonas/genética , Histonas/imunologia , Humanos , Imunoglobulina G/imunologia , Histona Desmetilases com o Domínio Jumonji/genética , Histona Desmetilases com o Domínio Jumonji/imunologia , Lúpus Eritematoso Sistêmico/genética , Lúpus Eritematoso Sistêmico/imunologia , Lisina/metabolismo , Proteína de Leucina Linfoide-Mieloide/genética , Proteína de Leucina Linfoide-Mieloide/imunologia , Regiões Promotoras Genéticas , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/imunologia , RNA Interferente Pequeno/imunologia , Células T Auxiliares Foliculares/imunologia , Linfócitos T Auxiliares-Indutores/imunologiaRESUMO
The medium-thick Al/Mg dissimilar friction stir welding (FSW) joint has serious groove and cavity defects due to uneven thermal distribution in the thickness direction. The submerged friction stir welding (SFSW) was employed to decrease the peak temperature of the joint and control the thermal gradient of the thickness direction, which were beneficial in suppressing the coarsening of the intermetallic compounds (IMCs) layer and improving the weld formation. According to the SEM results, the thickness value of the IMC layer in the nugget zone and shoulder affect zone decreased from 0.78 µm and 1.31 µm in FSW process to 0.59 µm and 1.21 µm in SFSW process at the same parameter, respectively. Compared with the FSW process, SFSW improves the thermal accumulation during the process, which inhibits the formation of the IMCs and facilitates the material flow to form a mechanical interlocking structure. This firm interface formation elevates the effective contact area of the whole joint interface and provides a strong connection between the dissimilar metals. Thus, the ultimate strength of the 6 mm thick Al/Mg dissimilar SFSW joints was enhanced to 171 MPa, equivalent to 71.3% of AZ31B Mg alloys strength.
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BACKGROUND: Overproduction of cAMP-responsive element modulator α (CREMα) in total T cells from patients with systemic lupus erythematosus (SLE) can inhibit IL-2 and increase IL-17A. These ultimately promote progression of SLE. This study aims to investigate the expression of CREMα in SLE CD4+ T cells and find out the mechanisms for the regulation of CREMα in SLE CD4+ T cells. RESULTS: CREMα mRNA was overexpressed in CD4+ T cells from SLE patients. The levels of histone H3 lysine 9 trimethylation (H3K9me3) and suppressor of variation 3-9 homolog 1 (SUV39H1) at the CREMα promoter of SLE CD4+ T cells were markedly decreased. Down-regulating SUV39H1 in normal CD4+ T cells elevated the levels of CREMα, IL-17A, and histone H3 lysine 4 trimethylation (H3K4me3) in the CREMα promoter region, and lowered IL-2, H3K9me3, DNA methylation, and DNA methyltransferase 3a (DNMT3a) enrichments within the CREMα promoter, while no sharp change in SET domain containing 1 (Set1) at the CREMα promoter. Up-regulating SUV39H1 in SLE CD4+ T cells had the opposite effects. The DNA methylation and DNMT3a levels were obviously reduced, and H3K4me3 enrichment was greatly increased at the CREMα promoter of CD4+ T cells from SLE patients. The Set1 binding in the CREMα promoter region upgraded significantly, and knocking down Set1 in SLE CD4+ T cells alleviated the H3K4me3 enrichment within this region, suppressed CREMα and IL-17A productions, and promoted the levels of IL-2, CREMα promoter DNA methylation, and DNMT3a. But there were no obviously alterations in H3K9me3 and SUV39H1 amounts in the region after transfection. CONCLUSIONS: Decreased SUV39H1 in the CREMα promoter region of CD4+ T cells from SLE patients contributes to under-expression of H3K9me3 at this region. In the meantime, the Set1 binding at the CREMα promoter of SLE CD4+ T cells is up-regulated. As a result, DNMT3a and DNA methylation levels alleviate, and H3K4me3 binding increases. All these lead to overproduction of CREMα. Thus, the secretion of IL-2 down-regulates and the concentration of IL-17A up-regulates, ultimately promoting SLE.
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Modulador de Elemento de Resposta do AMP Cíclico , Histonas , Lúpus Eritematoso Sistêmico , Metiltransferases , Proteínas Repressoras , Humanos , Autoimunidade/genética , Linfócitos T CD4-Positivos/metabolismo , Metilação de DNA , DNA Metiltransferase 3A , Histonas/metabolismo , Interleucina-17/genética , Interleucina-2/genética , Interleucina-2/metabolismo , Lúpus Eritematoso Sistêmico/genética , Lisina/metabolismo , Metiltransferases/genética , Regiões Promotoras Genéticas , Proteínas Repressoras/genética , Linfócitos T/metabolismo , Modulador de Elemento de Resposta do AMP Cíclico/metabolismoRESUMO
Solid-state lithium batteries (SSLBs) based on Ta-doped Li6.5La3Zr1.5Ta0.5O12 (LLZTO) suffer from lithium dendrite growth, which hinders their practical application. Herein, first principles simulations indicate that the Ta element prefers to segregate along grain boundaries in the form of Ta2O5 precipitates due to a high energy difference induced by Ta doping. Grain boundary engineering is employed to regulate the distribution of the Ta element and enhance the density of LLZTO by introducing the La2O3 additive. The sufficient La2O3 additive reacts with the Ta2O5 precipitates, while the residual La2O3 nanoparticles fill up void defects, promoting the homogeneous distribution of the Ta element and improving the relative density to â¼98%. Critical current density of the symmetric Li battery reaches 2.12 mA·cm-2 at room temperature with the solid-state electrolyte (LLZTO + 5 wt % La2O3), which increases by 41% compared to pure LLZTO. SSLBs with the LiFePO4 cathode achieve a stable cycling performance with a discharge capacity of 138.6 mA·h·g-1 after 400 cycles at 0.2 C. This work provides theoretical insights into the distribution of Ta-doped LLZTO and inhibits lithium dendrite growth through grain boundary engineering.
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The temperature and material flow gradients along the thick section of the weld seriously affect the welding efficiency of friction stir welding in medium-thick plates. Here, the effects of different gradients obtained by the two pins on the weld formation, microstructure, and mechanical properties were compared. The results indicated that the large-tip pin increases heat input and material flow at the bottom, reducing the gradient along the thickness. The large-tip pin increases the welding speed of defect-free joints from 100 mm/min to 500 mm/min compared to the small-tip pin. The ultimate tensile strength and elongation of the joint reached 247 MPa and 8.7%, equal to 80% and 65% of the base metal, respectively. Therefore, reducing the temperature and material flow gradients along the thickness by designing the pin structure is proved to be the key to improving the welding efficiency for thick plates.
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The antagonism between strength and corrosion resistance in graphene-reinforced aluminum matrix composites is an inherent challenge to designing reliable structural components. Heteroatom microstructural modification is highly appreciated to conquer the obstacle. Here, a bottom-up strategy to exploit the heterogeneous phase interface to enable high corrosion durability is proposed. Deformation-driven metallurgy derived from severe plastic deformation is developed to produce Mg-alloyed fluorinated graphene structures with homogeneous dispersion. These structures allow for absorbing corrosion products, forming a dense protective layer against corrosion, and local micro-tuning of the suppression of charge transfer. This results in superior corrosion resistance with an outstanding strength-ductility balance of the composites via ultrafine-grained and precipitation strengthening. The anti-corrosion polarization resistance remains 89% of the initial state after 2-month immersion in chloride-containing environment, while the ultra-tensile strength and elongation of 532 ± 39 MPa and 17.3 ± 1.2% are obtained. The economical strategy of heteroatom modification broadens the horizon for anti-corrosion engineering in aluminum matrix composites, which is critical for the design of carbonaceous nanomaterial-reinforced composites to realize desired performances for practical applications.