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The fabrication of molecular crystalline materials with fast, multistimuli-responsive behavior and the construction of the corresponding structure-activity relationship are of extraordinary significance for the development of smart materials. In this context, three multistimuli-responsive functional metal-organic polyhedra (MOP), {[Dy2(bcbp)3(NO3)1.5(H2O)7]·Cl4.2·(NO3)0.3·H2O}n (1), {[Dy2(bcbp)4(H2O)8]Cl6}n (2), and {[Eu2(bcbp)4(H2O)10]Cl6·H2O}n (3; bcbp = 1,1'-bis(4-carboxyphenyl)-4,4'-bipyridinium), were successfully prepared and characterized. All of the compounds exhibit rapid and reversible photochromic and electrochromic dual-responsive behaviors. Furthermore, benefiting from the well-defined crystal structure and different responsive behaviors, the photoinduced electron transfer (PIET) process and structure-activity relationship were explored. In addition, considering the excellent photochromic performance, function filter paper and smart organic glass were successfully prepared and used for ink-free printing and UV light detection.
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The precise control of the regioselectivity in the transition metal-catalyzed migratory hydrofunctionalization of alkenes remains a big challenge. With a transient ketimine directing group, the nickel-catalyzed migratory ß-selective hydroarylation and hydroalkenylation of alkenyl ketones has been realized with aryl boronic acids using alkyl halide as the mild hydride source for the first time. The key to this success is the use of a diphosphine ligand, which is capable of the generation of a Ni(II)-H species in the presence of alkyl bromide, and enabling the efficient migratory insertion of alkene into Ni(II)-H species and the sequent rapid chain walking process. The present approach diminishes organosilanes reductant, tolerates a wide array of complex functionalities with excellent regioselective control. Moreover, this catalytic system could also be applied to the migratory hydroarylation of alkenyl azahetereoarenes, thus providing a general approach for the preparation of 1,2-aryl heteroaryl motifs with wide potential applications in pharmaceutical discovery.
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Heterostyly, a plant sexual polymorphism controlled by the S-locus supergene, has evolved numerous times among angiosperm lineages and represents a classic example of convergent evolution in form and function. Determining whether underlying molecular convergence occurs could provide insights on constraints to floral evolution. Here, we investigated S-locus genes in distylous Gelsemium (Gelsemiaceae) to determine whether there is evidence of molecular convergence with unrelated distylous species. We used several approaches, including anatomical measurements of sex-organ development and transcriptome and whole-genome sequencing, to identify components of the S-locus supergene. We also performed evolutionary analysis with candidate S-locus genes and compared them with those reported in Primula and Turnera. The candidate S-locus supergene of Gelsemium contained four genes, of which three appear to have originated from gene duplication events within Gelsemiaceae. The style-length genes GeCYP in Gelsemium and CYP734A50 in Primula likely arose from duplication of the same gene, CYP734A1. Three out of four S-locus genes in Gelsemium elegans were hemizygous, as previously reported in Primula and Turnera. We provide genomic evidence on the genetic convergence of the supergene underlying distyly among distantly related angiosperm lineages and help to illuminate the genetic architecture involved in the evolution of heterostyly.
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Magnoliopsida , Primula , Genómica , Primula/genética , Plantas , Duplicación de Gen , Flores/genéticaRESUMEN
Fluorophores and hydrogen bonding interactions play key roles in the fluorescence properties of bottom-up carbon dots. In this work, an excited-state intramolecular proton-transfer (ESIPT) active fluorophore, 5-chloro-6-ethoxy-4,7-dihydroxyisoindoline-1,3-dione (CEDD) and a non-ESIPT 7-cyano-5,8-dihydroxyquinoxaline-6-carboxamide (CDQC) are extracted from 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) based carbon dots. The enol form of CEDD shows a weak blue, small Stokes shift and short lifetime emission under the aprotic or alkali conditions, but the keto form exhibits a strong green, large Stokes shift and long lifetime emission in a protic or an acidic environment. Due to the lack of the ESIPT process, CDQC has no dual emission characteristics, but shows efficient solid-state emission. By virtue of the ESIPT ability of CEDD, multiple anti-counterfeiting methods are achieved by using hydrogen chloride, ammonia, and fluorescence lifetime imaging, as well as dimethyl sulfoxide as the encryption/decryption tools.
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The edge doping effect would help improve the carbon-based electrocatalysis. Herein, we present an all-mechanical technique for the fabrication of cut, exfoliated N-doped carbon nanotubes (C, E-N-CNTs). Such nanohybrids with an edge-N-rich structure are obtained through sequential doping and mechanical treatments of the pristine bulk-CNTs. The C, E-N-CNT/carbon black (C, E-N-CNT/C) demonstrates exciting oxygen reduction reaction (ORR) electrocatalysis with exceptionally low-onset potential (E0, 913 mV versus RHE) and satisfactory half-wave potential (E1/2, merely -7.3 mV shift compared with that of commercial 20% platinum/C (Pt/C)). Besides, the C, E-N-CNT/C presents significantly enhanced durability and tolerance in chronoamperometry test with methanol injection compared with the Pt/C. Our work would facilitate the mass production and full exploration of nonmetallic electrocatalysts.
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A direct strategy for the selective synthesis of 3-acyl-1,2,4-oxadiazoles from alkynes and nitriles has been developed under iron(III) nitrate-mediated conditions. The mechanism includes three sequential procedures: iron(III) nitrate-mediated nitration of alkynes leads to α-nitroketones, dehydration of α-nitroketones provides the nitrile oxides, and 1,3-dipolar cycloaddition of nitrile oxides with nitriles produces 3-acyl-1,2,4-oxadiazoles under iron-mediated conditions. Iron(III) nitrate plays dual roles in the nitration of alkynes and the activation of nitriles, while the formation of pyrimidine/isoxazole byproducts can be efficiently inhibited.
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The study was conducted to evaluate the effects of heat stress on antioxidant status, immune response, and related gene expression of lambs. Eighteen male lambs were randomly allocated into three treatment groups that were as follows: indoor temperature control group furnished with an air-conditioner (ITC), indoor temperature non-control group suffered intermittent and varying degrees of heat stress (ITNC), outdoor temperature non-control group in the external natural environment (OTNC). ITNC group presented a more severe and prolonged exposure to thermal stress than the other two groups. The trial lasted 28 days. Blood samples were collected on days 14 and 28 to analyze total superoxide dismutase (T-SOD), catalase (CAT), glutathione peroxidase (GPx) activities, malondialdehyde (MDA) concentrations, total antioxidant capacity (T-AOC), interleukin-1 (IL-1), interleukin-2 (IL-2), tumor necrosis factor-alpha (TNF-α), immunoglobulin A (IgA), immunoglobulin G (IgG), and immunoglobulin M (IgM) concentrations and gene expressions of SOD1, SOD2, GPx, CAT, nuclear factor erythroid 2-related factor 2 (Nrf2), IL-1ß, IL-2, and TNF-α. Results showed that on day 14 an elevated temperature reduced (p < 0.05) the level of GPx, T-SOD, T-AOC, and IgG, whereas significantly increased (p < 0.05) CAT, MDA, IgA, and TNF-α levels. Gene expressions of SOD1 and GPx were down-regulated (p < 0.05). On day 28, ITNC group significantly decreased (p < 0.05) CAT, GPx, T-SOD, T-AOC, IgG, and IL-2 levels and increased (p < 0.05) MDA, IL-1, and TNF-α levels, accompanying by the reducing or increasing (p < 0.05) of their relative gene expression apart from CAT and IL-1ß gene (p > 0.10). In addition, in ITNC and OTNC groups, the level of CAT, T-SOD, T-AOC, IgG, IgM, and IL-2 and the expression of CAT, SOD2, and IL-2 reduced (p < 0.05), whereas IL-1 and TNF-α levels and IL-1ß expression increased (p < 0.05) on day 28 compared with day 14. In ITC group, the level of IgA, IL-1, and TNF-α and the expression of IL-1ß and TNF-α increased (p < 0.05), while the content of IgG and IgM reduced (p < 0.05) on day 28 compared with day 14. These results indicated that heat stress negatively affected the antioxidant status and immune response of lambs, and the negative effects of heat stress are not only related to the stress duration but also associated with the stress severity.
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Antioxidantes , Cyprinidae , Alimentación Animal/análisis , Animales , Dieta , Respuesta al Choque Térmico , Masculino , Estrés Oxidativo , OvinosRESUMEN
Lead halide perovskite quantum dots (PQDs) have recently been proposed as a scalable and color-tunable quantum source, but their slow spontaneous emission creates a mismatch with high-speed nanophotonic devices. Here, we demonstrate fast and bright emission in PQD films coupled to silver nanowire networks (NWKs), in which polyvinyl alcohol (PVA) is used as a spacer to regulate the lossy characteristics of the plasmonic cavity. Compared with bare quartz, the PVA substrate shows a considerable enhancement effect on the apparent emission intensity, but a reduction in the emission rate of PQD excitons. The efficient NWK-PQD coupling generates an increase in the emission intensity of a factor of 6.0 (average 3.4) and simultaneously a 2.4-fold (average 1.9) enhancement in the emission rate. However, an opposite PVA spacer thickness dependence for Purcell factor and quantum yield is observed, indicating that the fast and bright emission would be a trade-off between the Purcell-enhanced radiative rate and large metal loss. These results are believed to provide fundamental guidance on plasmonic cavity design for perovskite-based nanophotonic devices.
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The present experiment was conducted to investigate the effects of water extract of Artemisia ordosica (WEAO) on growth performance, antioxidant capability and immune response in weanling piglets. Seventy-two 28-day-old weanling piglets were randomly allocated into four treatments with six replicate pens per treatment and three piglets per pen (n = 18). These four treatment diets were formulated by adding 0, 250, 500 and 750 mg/kg WEAO to the basal diet. The experiment lasted for 28 days. Body weight and feed intake were measured. Blood samples were collected to determine immune and antioxidative parameters. The experimental results showed that WEAO supplementation improved the apparent nutrient digestibility of piglets in a linear or quadratic dose-dependent manner. In addition, dietary WEAO quadratically increased serum concentrations of cytokines interleukin (IL)-1, IL-4, tumour necrosis factor (TNF)-α, soluble surface antigen CD8 (sCD8), immunoglobulins (Ig)-A and linearly increased serum concentrations of IL-2, IL-6, IgG, IgM. Furthermore, dietary WEAO linearly or quadratically decreased serum concentrations of malondialdehyde but quadratically increased activities of antioxidant enzymes and total antioxidative capacity. These results suggested that WEAO may prove useful as a natural phytogenic feed additive with antioxidative potential and could be incorporated into diets of piglets.
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Antioxidantes/metabolismo , Artemisia/química , Extractos Vegetales/farmacología , Porcinos/fisiología , Alimentación Animal/análisis , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Dieta/veterinaria , Femenino , Masculino , Extractos Vegetales/química , Aumento de Peso/efectos de los fármacosRESUMEN
BACKGROUND/AIMS: Nodal cilia that rotate in the ventral node play an important role in establishing left-right asymmetry during embryogenesis; however, inv mutant cilia present abnormal movement and induce laterality defects. The mechanism of their motility, which is regulated by dynein activation and microtubule arrangement, has not been fully understood. This study analyzed the dynein-triggered ciliary motion in the abnormal ultrastructure of the inv mutant, aiming to quantitatively evaluate the influence of microtubule mislocalization on the movement of the cilium. METHODS: We established a realistic 3-D model of an inv mutant cilium with an ultrastructure based on tomographic datasets generated by ultra-high voltage electron microscopy. The time-variant activation of the axonemal dynein force was simulated by pairs of point loads and embedded at dynein-mounted positions between adjacent microtubule doublets in this mathematical model. Utilizing the finite element method and deformable grid, the motility of the mutant cilium that is induced by various dynein activation hypotheses was investigated and compared to experimental observation. RESULTS: The results indicate that for the inv mutant, simulations of the ciliary movement with the engagement of dyneins based on the distance-controlled pattern in the partially activation scenario are broadly consistent with the observation; the shortening of the microtubules induces smaller movement amplitudes, while the angles of the mislocalized microtubules affect the pattern of the ciliary movement, and during the ciliary movement, the microtubules swing and twist in the mutant ciliary body. CONCLUSION: More generally, this study implies that dynein engagement is sensitive to subtle geometric changes in the axoneme, and thus, this geometry greatly influences the integrity of a well-formed ciliary rotation.
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Cilios/fisiología , Dineínas/metabolismo , Microtúbulos/metabolismo , Animales , Cilios/ultraestructura , Simulación por Computador , Dineínas/ultraestructura , Módulo de Elasticidad , Desarrollo Embrionario , Ratones Endogámicos ICR , Microtúbulos/ultraestructura , Modelos Biológicos , MovimientoRESUMEN
A simple and direct method for the iron(III) nitrate-mediated synthesis of isoxazoles from alkynes has been developed; both self-coupling and cross-coupling products could be successfully prepared from alkynes. Meanwhile, for the cross-coupling and cyclizing of two different alkynes examined, the iron-mediated system shows a good chemoselectivity for the synthesis of corresponding isoxazoles. In our method, cheap and eco-friendly iron(III) nitrate is used as the nitration and cyclization reagent, and KI is used as the additive; they both play a positive role in this transformation. Furthermore, a different mechanism for the formation of isoxazoles from alkynes has been proposed.
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A simple and efficient method for the base-mediated synthesis of unsymmetrical 1,3,5-triazin-2-amines has been developed. The protocol uses readily available imidates, guanidines, and amides or aldehydes as the starting materials, cesium carbonate as the base, no catalyst or additive is required, and the three-component reaction provides diverse 1,3,5-triazin-2-amines in moderate to good yields with tolerance of wide functional groups.
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A simple and practical method for I2-mediated one-pot synthesis of 3-alkyl-5-aryl-1,2,4-thiadiazoles has been developed; the one-pot reaction includes sequential intermolecular addition of thioamides to nitriles, and intramolecular oxidative coupling of N-H and S-H bonds mediated by molecular iodine. Meanwhile the protocol uses readily available nitriles and thioamides as the starting materials, molecular iodine as the oxidant, and generates various 1,2,4-thiadiazoles in moderate to good yields with a wide array of functional groups. This method is an efficient approach for the synthesis of unsymmetrically disubstituted 1,2,4-thiadiazoles.
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Recently, graphene nanodots (GNDs) have been frequently considered as inherently heterogeneous systems, leading to multicolor emission under a changeable excitation wavelength. However, an accurate picture of the GNDs and an exhaustive structure-property correlation are still lacking. Using a two dimensional photoluminescence excitation (2D-PLE) map, molecular orbital calculation, reduction level dependent PL analysis, absorption spectroscopy and time-resolved PL spectroscopy, three cases of quasi-molecular PL are determined in ethylenediamine (EDA) reduced GNDs, including the C[double bond, length as m-dash]O related electronic state, graphenol related electronic state and large π-conjugated domains. The graphenol structure is expected to be created via nucleophilic addition-elimination reactions between epoxide groups and EDA, contributing most to the blue-shifted and enhanced PL of GNDs. The multiple quasi-molecular PL provides deeper insights into the commonly called "excitation wavelength dependent PL". An effort is made to utilize the heterogeneous photoluminescence through phosphor-based light-emitting diodes employing reduced GNDs as a phosphor, which are capable of converting blue light into white light.
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A simple base-mediated one-pot synthesis of 3,5-disubstituted 1,2,4-oxadiazoles from nitriles, aldehydes and hydroxylamine hydrochloride has been developed, in which the aldehydes act as both substrates and oxidants. The reactions include three sequential procedures: base-promoted intermolecular addition of hydroxylamine to nitrile to lead to amidoxime, treatment of the amidoxime with an aldehyde to form 4,5-dihydro-1,2,4-oxadiazole, and oxidization of the 4,5-dihydro-1,2,4-oxadiazole by using another aldehyde to afford 1,2,4-oxadiazole. This method represents a direct and simple protocol for the synthesis of 3,5-disubstituted 1,2,4-oxadiazoles.
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A simple and efficient copper-catalyzed one-pot synthesis of substituted 1,2,4-triazoles through reactions of two nitriles with hydroxylamine has been developed. The protocol uses simple and readily available nitriles and hydroxylamine hydrochloride as the starting materials and inexpensive Cu(OAc)2 as the catalyst, and the corresponding 1,2,4-triazole derivatives are obtained in moderate to good yields. The reactions include sequential intermolecular addition of hydroxylamine to one nitrile to provide amidoxime, copper-catalyzed treatment of the amidoxime with another nitrile, and intramolecular dehydration/cyclization. This finding provides a new and useful strategy for synthesis of 1,2,4-triazole derivatives.
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Cobre/química , Hidroxilamina/química , Nitrilos/química , Triazoles/síntesis química , Catálisis , Ciclización , Estructura Molecular , Triazoles/químicaRESUMEN
In this work, few layer graphene quantum dots (GQDs) with a size of 3-5 nm are purposely treated with highly concentrated aqueous NaBH4 solutions to obtain the reduced graphene quantum dots (rGQDs). Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy demonstrate that the number of carbonyl groups decreases but -OH related defects increase during chemical reduction. Green and weak emissions of original GQDs originate from carrier recombination in the disorder-induced localized state (mainly including carbonyl and carboxyl and epoxy groups). As the reduction degree increases, the photoluminescence (PL) quantum efficiency of GQDs increases dramatically from 2.6% to 10.1%. In the meantime, the PL peak position blue shifts rapidly, and full width at half maximum (FWHM) becomes narrower. Thus we can infer that graphenol topological defects (hydroxyl functionalized graphene) are gradually formed during reduction. Besides, graphenol defect related PL features a longer fluorescence lifetime, excitation wavelength dependence but less pH sensitivity.
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Cold conditions in northern China during winter may reduce sheep growth and affect their health, especially if they are young, unless housing is provided. We allocated 45 two-month-old female lambs to be housed in an enclosed building, a polytunnel, or kept outdoors, for 28 days. The daily weight gain and scalp and ear skin temperature of outdoor lambs were less than those of lambs that were housed in either a house or polytunnel; however, rectal temperature was unaffected by treatment. There was a progressive change in blood composition over time, and by the end of the experiment, outdoor lambs had reduced total antioxidant capacity (T-AOC), catalase (CAT), glutathione peroxidase (GSH-Px) and total superoxide dismutase (T-SOD) and increased malondialdehyde compared to those in the house or polytunnel. In relation to immune responses in the lambs' serum, in the polytunnel, immunoglobulin A (IgA), tumor necrosis factor-α (TNF-α) and interleukin-4 (IL-4) were higher and immunoglobulin G (IgG) lower compared with the concentrations in lambs that were outdoors. Over the course of the experiment, genes expressing heat shock proteins and antioxidant enzymes increased in lambs in the outdoor treatment, whereas they decreased in lambs in the indoor treatments. It is concluded that although there were no treatment effects on core body temperature, the trends for progressive changes in blood composition and gene expression indicate that the outdoor lambs were not physiologically stable; hence, they should not be kept outdoors in these environmental conditions for long periods.
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Underwater explosions (UNDEX) generate shock waves that interact with the air-water interface and structures, leading to the occurrence of rarefaction waves and inducing cavitation phenomena. In deep-water explosions, complex coupling relationships exist between shock wave propagation, bubble motion, and cavitation evolution. The shock wave initiates the formation of cavitation, and their growth and collapse are influenced by the pressure field. The collapsing bubbles generate additional shock waves and fluid motion, affecting subsequent shock wave propagation and bubble behavior. This intricate interaction significantly impacts the hydrodynamic characteristics of deep-water explosions, including pressure distribution, density, and phase changes in the surrounding fluid. In this paper, we utilize a two-fluid phase transition model to capture the evolution of cavitation in deep-water explosions. Our numerical results demonstrate that the introduction of a two-phase vapor-liquid phase change model is necessary to accurately capture scenarios involving prominent evaporation or condensation phenomena. Furthermore, we find that the cavitation produced by the same charge under different explosion depths exhibits significant differences, as does the peak value of cavitation collapse pressure. Similarly, the cavitation produced by different charge quantities under the same explosion depth varies, and the relationship between cavitation volume and charge quantity is not a simple linear increase. The research methods and results presented in this paper provide an important reference for studying the dynamic characteristics of deep-water explosions.
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With the high intensification of poultry breeding, a series of diseases caused by pathogenic bacteria threaten the health of poultry and human. Among them, poultry diseases induced by Escherichia coli cause significant economic loss every year. The aim of this study was to investigate the effects of dietary supplementation with Artemisia annua L. polysaccharide (AAP) on the growth performance and intestinal barrier function of broilers with Escherichia coli (E. coli) challenge. A total of 256 one-day-old chicks were randomly assigned to four treatment groups: control group (fed basal diet), AAP group (fed basal diet supplemented with AAP), E. coli group (fed basal diet and orally administered E. coli), AAP + E. coli group (fed basal diet supplemented with AAP and orally administered E. coli). Dietary AAP supplementation elevated the BW, ADG and ADFI in non-challenged broilers. AAP also increased the apparent metabolic rate of EE and Ca in E. coli-challenged broilers. Moreover, AAP not only enhanced the serum IgA content but also decreased the serum and jejunum content of IL-6, as well as the jejunum level of IL-1ß in non-challenged broilers. AAP also down-regulates the mRNA level of inflammatory factors (IL-1ß, IL-6, and TNF-α) by inhibiting the mRNA expression of TLR4 and MyD88 in intestinal NF-κB signaling pathway of E. coli-challenged broilers. Meanwhile, AAP up-regulates the activity and mRNA level CAT by down-regulating the mRNA level of Keap1 in intestinal Nrf2 signaling pathway of E. coli-challenged broilers, and decreased serum MDA concentration. AAP significantly elevated the mRNA level of CAT, SOD and Nrf2 in jejunal of non-challenged broilers. Interestingly, AAP can improve intestinal physical barrier by down-regulating serum ET content, increasing the jejunal villus height/crypt depth (VH/CD) and ZO-1 mRNA level in broilers challenged by E. coli. AAP also elevated the VH/CD and the mRNA level of Occludin, ZO-1, Mucin-2 in non-challenged broilers. Importantly, AAP reshaped the balance of jejunum microbiota in E. coli-challenged broilers by altering α diversity and community composition. In summary, AAP ameliorated the loss of growth performance in broilers challenged with E. coli, probably by regulating the intestinal permeability and mucosa morphology, immune function, antioxidant ability, and microbiota.