In this study, the two-phase flow coordination characteristics between α and β phases of H62 brass made by up-drawing continuous casting are investigated based on the upsetting process. An in situ ...and new research method for two-phase flow is put forward, and the two-phase flow and grain refinement characteristics are observed under different deformation conditions. The results show that α phase flows fast under 400 °C, β phase is pulled and overridden by α phase under this temperature. When the temperature increases to 500 °C, which is higher than β phase transition temperature, the flow velocity of β phase increases, and the deformation of β phase is found to bulge. The flow of β phase is more sensitive to low deformation rates than α phase. The deformation amount has a more significant impact on β phase than α phase, and the deformation of β phase promotes the grain fragmentation and refinement of α phase accompanied by huge β phase bulging obviously. Under the conditions of high temperature, low deformation rate, and large deformation amount, both phase α and β of up-drawing continuous casting brass alloy are broken and the grains are refined. Based on the two-phase flow characteristic, numerical simulation is used to obtain the optimal continuous extrusion parameters of the H-shaped wire of up-drawing continuous casting H62 brass. Then, the optimized complex cross-section wire is prepared by continuous extrusion experiment. This research aims to provide guidance for the complex processing of two-phase alloys.
•CuCr30 with uniform microstructure was successfully prepared by laser additive manufacturing.•Both strength and electrical conductivity of the prepared CuCr30 are improved by continuous ...extrusion.•The insoluble second phase has a unique effect on the microstructure evolution of Cu matrix during plastic deformation.•The property improvement is attributed to the increase of density, grain refinement and nano-twin.
Cu‒Cr alloy is a kind of functional and structural integrated material with excellent comprehensive mechanical and electrical properties. However, due to the low solubility of Cr in Cu and the huge difference in melting point, the existing methods to manufacture well-structured Cu‒Cr alloys are facing many challenges. In this paper, laser additive manufacturing (LAM) is applied to manufacture CuCr30 with ideal structure, taking advantage of its characteristics such as the small molten pool and fast crystallization. A small amount of microporosity defects formed during the LAM process were then reduced by severe shear deformation in the subsequent continuous extrusion process. As a result, the strength of the CuCr30 was increased by 55.3% and the room temperature conductivity was increased by 6.6%. Although the Cu grain refinement leads to fine grain strengthening and the homogenization of Cr distribution leads to enhancement of second phase strengthening during continuous extrusion, both have a negative effect on conductivity, the room temperature conductivity of CuCr30 did not decrease, because of the reduction of pore defects and the formation of nano-twinned structure with thickness of 10–30 nm, which improves the strength without affecting the conductivity.
Laser powder bed fusion (L-PBF) technology is an appropriate scheme for producing intricate components with complex internal structures, such as the intricate flow channel networks in aircraft ...hydraulic manifolds. However, it is an enormous challenge to fabricate circular channels without support structures that exhibit low shape deviation and high surface quality through L-PBF. This study introduces an innovative annular gradient-forming process that divides the circular flow channel into three sections, namely the inner layer, the transition layer, and the substrate, sequentially from the inside to the outside along the radial direction. Throughout the L-PBF process, the laser energy density is incrementally increased for the inner layer, transition layer, and substrate. The research focuses on manufacturing Ti6Al4V (TC4) circular channels with a diameter of 10 mm, exploring various process parameters to achieve low surface roughness, high dimensional accuracy, and low porosity through the annular gradient process. The effectiveness of the proposed annular gradient process and its parameters is validated through the fabrication and testing of circular channels with diameters of 8 mm, 10 mm, and 12 mm. The results demonstrate that the root mean square deviation (RMS) of the horizontal circular channels using the annular gradient process is reduced by over 80%, and the surface roughness Ra is reduced by over 50%. Furthermore, the channels also have better mechanical properties.
•An innovative annular gradient process method is introduced for circular channels.•The effects of process parameters on forming quality of channels are investigated.•The annular gradient process effectively reduces dimensional deviations and surface roughness.•The annular gradient process ensures high strength and low porosity in channels.
•The continuous extrusion refines the grain size of Cu-Te alloy significantly by incomplete dynamic recrystallization.•Cu2Te phase stimulates the formation of recrystallization and inhibit subgrain ...growth.•The increments caused by dislocation strengthening and boundary strengthening account for 84.6% of the yield strength of the extruded Cu-Tealloy and the electrical resistivity induced by grain boundaries and dislocations accounts for 1.6% of the electrical resistivity of the extruded Cu-Te alloy.•Dislocations and boundaries contribute greatly to the increase of yield strength, but less to the increase of electrical resistivity.
The microstructure, mechanical performance, and electrical conductivity of Cu-Te alloy fabricated by continuous extrusion were quantitatively investigated. The results demonstrate that the grain size of the Cu-Te alloy is refined significantly by incomplete dynamic recrystallization. The Cu2Te phase stimulates recrystallization and inhibits subgrain growth. After extrusion, the tensile strength increases from 217.8 ± 4.8 MPa to 242.5 ± 3.7 MPa, the yield strength increases from 65.1 ± 3.5 MPa to 104.3 ± 3.8 MPa, and the yield to tensile strength ratio is improved from 0.293 ± 0.015 to 0.43 ±.0.091, while the electrical conductivity of room temperature decreases from 95.8 ± 0.38% International Annealed Cu Standard (IACS) to 94.0% ± 0.32% IACS. The quantitative analysis shows that the increment caused by dislocation strengthening and boundary strengthening account for 84.6% of the yield strength of the extruded Cu-Te alloy and the electrical resistivity induced by grain boundaries and dislocations accounts for 1.6% of the electrical resistivity of the extruded Cu-Te alloy. Dislocations and boundaries contribute greatly to the increase of yield strength, but less to the increase of electrical resistivity.
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A novel photocatalytic cyclization reaction was developed for the synthesis of quinazolinones from
o
-aminobenzamides and
in-situ
generated aldehydes from alcohols using 9-fluorenone as the ...photocatalyst through a "one-pot" process. Furthermore, alcohols are perfect alternatives to aldehydes due to some unique advantages, such as being green, less toxic, available, and economical. The present protocol showed good tolerance for various substrates and could afford a range of quinazolinones (29 examples) up to 91% under ambient conditions.
Graphical Abstract
Nitrogen (N) is an essential nutrient element in plants that participates in physiological and biochemical regulation. However, the effects of different N applications on cigar tobacco (Nicotiana ...tabacum L.) growth are not well known. In this study, the differences in agronomical characteristics and nutritional quality of cigar tobacco leaves at the mature and curing stages under different exogenous N applications were explored. The dry matter accumulation of cigar tobacco leaves increased with increasing N application rates. In the two stages, the nutritional quality of cigar tobacco leaves was similar, but the concentrations of N and Cl were increased. To understand the effect of exogenous N on cigar tobacco metabolism, untargeted metabolomics was applied. Six significantly differential metabolites, including phenylalanine, phosphoserine, glutamate, oxoproline, succinylhomoserine, and homoserine, were identified, and the main metabolic pathways around the tricarboxylic acid cycle were identified. These results provide a better understanding of the effects of exogenous N application on the physiological, biochemical, and metabolic processes of cigar tobacco and provide a reference for fertilization control in cigar tobacco production.
Core Ideas
Agronomical characteristics of cigar tobacco were significantly affected by N application rates.
Effect of N application rates on nutrient quality were reflected in several indices.
Amino acid metabolism of cigar tobacco was mainly affected by N application rates.
The dried fruit of Gardenia jasminoides Ellis (Zhizi in Chinese) is a traditional medicine used for thousands of years in China, Japan and Korea. Zhizi was recorded in Shennong Herbal, as a folk ...medicine, it reduces fever and treats gastrointestinal disturbance with antiphlogistic effects. Geniposide, an iridoid glycoside, is an important bioactive compound derived from Zhizi and possesses remarkable antioxidant and anti-inflammatory capacities. The pharmacological efficacy of Zhizi is highly related to the antioxidant and anti-inflammatory effects of geniposide.
Ulcerative colitis (UC) is a common chronic gastrointestinal disease as a global public health threat. Redox imbalance is an essential factor in the progression and recurrence of UC. This study aimed to explore the therapeutic effect of geniposide on colitis and uncover the underlying mechanisms of geniposide-mediated antioxidant and anti-inflammatory activities.
The study design involved investigating the novel mechanism by which geniposide ameliorates dextran sulfate sodium (DSS)-induced colitis in vivo and lipopolysaccharide (LPS)-challenged colonic epithelial cells in vitro.
The protective effect of geniposide against colitis was evaluated by histopathologic observation and biochemical analysis of colonic tissues in DSS-induced colitis mice. The antioxidant and anti-inflammatory effects of geniposide were evaluated in both DSS-induced colitis mice and LPS-challenged colonic epithelial cells. Immunoprecipitation, drug affinity responsive target stability (DARTS), and molecular docking were performed to identify the potential therapeutic target of geniposide and the potential binding sites and patterns.
Geniposide ameliorated the symptoms of DSS-induced colitis and colonic barrier injury, inhibited pro-inflammatory cytokine expression, and suppressed activation of the NF-κB signaling in colonic tissues of DSS-challenged mice. Geniposide also ameliorated lipid peroxidation and restored redox homeostasis in DSS-treated colonic tissues. In addition, in vitro experiments also showed that geniposide exhibited significant anti-inflammatory and antioxidant activity, as evidenced by suppressed IκB-α and p65 phosphorylation and IκB-α degradation, and enhanced the phosphorylation and transcriptional activity of Nrf2 in LPS-treated Caco2 cells. ML385, a specific Nrf2 inhibitor, abolished the protective effect of geniposide against LPS-induced inflammation. Mechanistically, geniposide could bind to KEAP1, thereby disrupting the interaction between KEAP1 and Nrf2, preventing Nrf2 from degradation and activating the Nrf2/ARE signaling pathway, ultimately suppressing the onset of inflammation caused by redox imbalance.
Geniposide ameliorates colitis by activation of Nrf2/ARE signaling, while preventing colonic redox imbalance and inflammatory damage, indicating that geniposide can be considered as a promising lead compound for the treatment of colitis.
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•Geniposide ameliorates DSS-induced colitis and suppresses inflammatory cytokine and NF-κB signaling activation.•Geniposide ameliorates lipid peroxidation and restores redox homeostasis in DSS-treated colonic tissues.•Geniposide also exhibits significant anti-inflammatory and antioxidant activity in LPS-treated Caco2 cells.•Geniposide activates the Nrf2/ARE signaling pathway and suppresses onset of inflammation caused by redox imbalance.•Geniposide interacts KEAP1 to prevent Nrf2 degradation and disrupt their binding.
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In this work, three artificial light-harvesting systems are constructed by a supramolecular approach in aqueous environment. The water-soluble bipyridinium derivatives (DPY1, DPY2, ...and DPY3) were self-assembled with cucurbit7uril (CB7) to form the host–guest DPY-CB7 complexes, which can highly disperse in water as small nanoparticles. The excited DPY-CB7 assemblies can transfer energy to the sulfo-rhodamine 101 (SR101) molecules at a high donor/acceptor ratio. With the help of hydrophobic cavity of CB7, the DPY-CB7 + SR101 systems can works as a nanoreactor for effective dehalogenation of α-bromoacetophenone and its derivatives in aqueous medium under white light irradiation. Such light-harvesting systems has greatly potential applications to realize some organic photocatalytic synthesis in aqueous environment.
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•Pmvb and CB8 formed supramolecular polymers via host-guest interactions.•Supramolecular polymers have an obvious fluorescence enhancement effect.•Supramolecular polymers were used to ...fabricate LHSs with RhB or SR101.•Two different efficient LHSs have been successfully constructed with a FRET process.
In the present work, artificial light-harvesting systems with a fluorescence resonance energy transfer (FRET) process were successfully obtained in the aqueous solution. We designed and synthesized an amphiphilic pyrene derivative with two 4-vinylpyridium arms (Pmvb), which can interact with cucurbit8uril (CB8) to form supramolecular polymer through host-guest interactions in aqueous solution. The formation of supramolecular polymers results in a significant enhancement of fluorescence, which makes Pmvb-CB8 an ideal energy donor to construct artificial light-harvesting systems in the aqueous solution. Subsequently, two different fluorescence dyes Rhodamine B (RhB) and Sulforhodamine 101 (SR101) were introduced as energy acceptors into the solution of Pmvb-CB8 respectively, to fabricate two different artificial light-harvesting systems. The obtained artificial light-harvesting systems can achieve an efficient energy transfer process from Pmvb-CB8 to RhB or SR101 with high energy transfer efficiency.
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•Luteolin improved DSS-induced colitis and attenuated colonic barrier injury.•Luteolin reduced inflammatory cytokines and suppressed NF-κB activation in colon.•Luteolin showed ...anti-inflammatory activity in LPS-stimulated macrophages in vitro.•Luteolin inhibited migration and chemotaxis of macrophages in response to CCL2.•Luteolin interacted with IKKα/β, then inhibited IKKα/β and NF-κB activation.
Luteolin, known for its multifaceted therapeutic properties against inflammatory diseases, holds potential for addressing the unmet need for effective treatments in ulcerative colitis (UC), a prevalent subtype of inflammatory bowel disease (IBD). This study aimed to comprehensively assess luteolin's therapeutic efficacy in a dextran sulfate sodium (DSS)-induced colitis mouse model, shedding light on its anti-UC mechanisms.
Our investigation encompassed in vivo assessments of luteolin's therapeutic potential against DSS-induced colitis through rigorous histopathological examination and biochemical analyses. Furthermore, we scrutinized luteolin's anti-inflammatory prowess in vitro using lipopolysaccharide (LPS)-stimulated RAW264.7 cells and primary peritoneal macrophages. Additionally, we quantitatively evaluated the impact of luteolin on C–C motif chemokine ligand 2 (CCL2)-induced macrophage migration employing Transwell and Zigmond chambers. Furthermore, cellular thermal shift assay (CETSA), drug affinity responsive target stability (DARTS) assay, and molecular docking were employed to identify potential therapeutic targets of luteolin and investigate their binding sites and interaction patterns.
Luteolin demonstrated therapeutic potential against DSS-induced colitis by ameliorating colitis symptoms, restoring intestinal barrier integrity, and inhibiting proinflammatory cytokine production in the colonic tissues. Moreover, luteolin demonstrated robust anti-inflammatory activity in vitro, in lipopolysaccharide (LPS)-stimulated RAW264.7 cells and primary peritoneal macrophages. Notably, luteolin suppressed the phosphorylation of IKKα/β, IκBα, and p65, along with preventing IκBα degradation in LPS-treated RAW264.7 cells and peritoneal macrophages. Furthermore, luteolin impaired the migratory behavior of RAW264.7 cells and peritoneal macrophages, as evidenced by reduced migration distance and velocity of luteolin-treated macrophages. Mechanistically, luteolin was found to antagonize IKKα/β, subsequently inhibiting IKKα/β phosphorylation and the activation of NF-κB signaling.
Luteolin emerges as a promising lead compound for the clinical therapy of colitis by virtue of its ability to ameliorate DSS-induced colitis, antagonize IKKα/β, suppress NF-κB signaling, and impede macrophage activation and migration.
