RESUMO
Asymmetric soft-stiff patch nanohybrids with small size, spatially separated organics and inorganics, controllable configuration, and appealing functionality are important in applications, while the synthesis remains a great challenge. Herein, based on polymeric single micelles (the smallest assembly subunit of mesoporous materials), we report a dynamic surface-mediated anisotropic assembly approach to fabricate a new type of small asymmetric organic/inorganic patch nanohybrid for the first time. The size of this asymmetric organic/inorganic nanohybrid is â¼20 nm, which contains dual distinct subunits of a soft organic PS-PVP-PEO single micelle nanosphere (12 nm in size and 632 MPa in Young' modulus) and stiff inorganic SiO2 nanobulge (â¼8 nm, 2275 MPa). Moreover, the number of SiO2 nanobulges anchored on each micelle can be quantitatively controlled (from 1 to 6) by dynamically tuning the density (fluffy or dense state) of the surface cap organic groups. This small asymmetric patch nanohybrid also exhibits a dramatically enhanced uptake level of which the total amount of intracellular endocytosis is about three times higher than that of the conventional nanohybrids.
RESUMO
In pursuing cheap and effective oxygen reduction catalysts, the Fe/N/C system emerges as a promising candidate. Nevertheless, the structural transformations of starting materials into Fe- and N-doped carbon catalysts remains poorly characterized under pyrolytic conditions. Here, we explore the evolution of Fe species and track the formation of Fe-N4 site development by employing diverse in-situ diagnostic techniques. In-situ heating microscopy reveals the initial formation of FeOx nanoparticles and subsequent internal migration within the carbon matrix, which stops once FeOx is fully reduced. The migration and decomposition of nanoparticles then leads to carbon layer reconstruction. Experimental and theoretical analysis reveals size-dependent behavior of FeOx where nanoparticles below 7 nm readily release Fe atoms to form Fe-N4 while nanoparticles with sizes >10 nm tend to coalesce and impede Fe-N4 site formation. The work visualizes the pyrolysis process of Fe/N/C materials, providing theoretical guidance for the rational design of catalysts.
RESUMO
Abiotic stresses pose a major increasing problem for the cultivation of maize. Autophagy plays a vital role in recycling and re-utilizing nutrients and adapting to stress. However, the role of autophagy in the response to abiotic stress in maize has not yet been investigated. Here, ZmATG3, which is essential for ATG8-PE conjugation, was isolated from the maize inbred line B73. The ATG3 sequence was conserved, including the C-terminal domains with HPC and FLKF motifs and the catalytic domain in different species. The promoter of the ZmATG3 gene contained a number of elements involved in responses to environmental stresses or hormones. Heterologous expression of ZmATG3 in yeast promoted the growth of strain under salt, mannitol, and low-nitrogen stress. The expression of ZmATG3 could be altered by various types of abiotic stress (200 mM NaCl, 200 mM mannitol, low N) and exogenous hormones (500 µM ABA). GUS staining analysis of ZmATG3-GUS transgenic Arabidopsis revealed that GUS gene activity increased after abiotic treatment. ZmATG3-overexpressing Arabidopsis plants had higher osmotic and salinity stress tolerance than wild-type plants. Overexpression of ZmATG3 up-regulated the expression of other AtATGs (AtATG3, AtATG5, and AtATG8b) under NaCl, mannitol and LN stress. These findings demonstrate that overexpression of ZmATG3 can improve tolerance to multiple abiotic stresses.
RESUMO
Thanks to their excellent photoelectric characteristics to generate cytotoxic reactive oxygen species (ROS) under the light-activation process, TiO2 nanomaterials have shown significant potential in photodynamic therapy (PDT) for solid tumors. Nevertheless, the limited penetration depth of TiO2-based photosensitizers and excitation sources (UV/visible light) for PDT remains a formidable challenge when confronted with complex tumor microenvironments (TMEs). Here, we present a H2O2-driven black TiO2 mesoporous nanomotor with near-infrared (NIR) light absorption capability and autonomous navigation ability, which effectively enhances solid tumor penetration in NIR light-triggered PDT. The nanomotor was rationally designed and fabricated based on the Janus mesoporous nanostructure, which consists of a NIR light-responsive black TiO2 nanosphere and an enzyme-modified periodic mesoporous organosilica (PMO) nanorod that wraps around the TiO2 nanosphere. The overexpressed H2O2 can drive the nanomotor in the TME under catalysis of catalase in the PMO domain. By precisely controlling the ratio of TiO2 and PMO compartments in the Janus nanostructure, TiO2&PMO nanomotors can achieve optimal self-propulsive directionality and velocity, enhancing cellular uptake and facilitating deep tumor penetration. Additionally, by the decomposition of endogenous H2O2 within solid tumors, these nanomotors can continuously supply oxygen to enable highly efficient ROS production under the NIR photocatalysis of black TiO2, leading to intensified PDT effects and effective tumor inhibition.
Assuntos
Raios Infravermelhos , Fotoquimioterapia , Fármacos Fotossensibilizantes , Titânio , Titânio/química , Titânio/farmacologia , Humanos , Porosidade , Animais , Camundongos , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacologia , Nanoestruturas/química , Espécies Reativas de Oxigênio/metabolismo , Peróxido de Hidrogênio/química , Peróxido de Hidrogênio/metabolismo , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Microambiente Tumoral/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Camundongos Endogâmicos BALB C , Proliferação de Células/efeitos dos fármacos , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Tamanho da PartículaRESUMO
Interfacial Lewis acid-base pairs are commonly found in ZrO2-supported metal catalysts due to the facile generation of oxygen vacancies of ZrO2. These pairs have been reported to play a crucial role in olefin hydroesterification, especially in the absence of acid promoters and ligands. In this study, a series of ZrO2-supported Ru catalysts with ruthenium(iii) chloride and ruthenium(iii) acetylacetonate as precursors were prepared for the styrene hydroesterification. The catalysts were thoroughly characterized by TPR, TEM, EPR, XPS, and FTIR. The Ru precursors significantly influenced the size and electronic properties of Ru clusters, albeit having minimal impact on oxygen vacancies. Mechanistic studies of styrene hydroesterification over ZrO2-supported Ru catalysts revealed that the carbon monoxide insertion followed the hydrogen transfer step to activated styrene. Higher activity is exhibited over ZrO2-supported Ru catalysts prepared with ruthenium(iii) chloride as a precursor, attributed to the lower adsorption strength of CO over Ru clusters, as evidenced by FTIR and DFT calculations.
RESUMO
OBJECTIVE: Branchio-oto-renal syndrome (BOR, OMIM#113,650) is a rare autosomal dominant disorder that presents with a variety of symptoms, including hearing loss (sensorineural, conductive, or mixed), structural abnormalities affecting the outer, middle, and inner ear, branchial fistulas or cysts, as well as renal abnormalities.This study aims to identify the pathogenic variants by performing genetic testing on a family with Branchio-oto-renal /Branchio-otic (BO, OMIM#602,588) syndrome using whole-exome sequencing, and to explore possible pathogenic mechanisms. METHODS: The family spans 4 generations and consists of 9 individuals, including 4 affected by the BOR/BO syndrome. Phenotypic information, including ear malformation and branchial cleft, was collected from family members. Audiological, temporal bone imaging, and renal ultrasound examinations were also performed. Whole-exome sequencing was conducted to identify candidate pathogenic variants and explore the underlying molecular etiology of BOR/BO syndrome by minigene experiments. RESULTS: Intra-familial variability was observed in the clinical phenotypes of BOR/BO syndrome in this family. The severity and nature of hearing loss varied in family members, with mixed or sensorineural hearing loss. The proband, in particular, had profound sensorineural hearing loss on the left and moderate conductive hearing loss on the right. Additionally, the proband exhibited developmental delay, and her mother experienced renal failure during pregnancy and terminated the pregnancy prematurely. Genetic testing revealed a novel heterozygous variant NM_000503.6: c.639 + 3 A > C in the EYA1 gene in affected family members. In vitro minigene experiments demonstrated its effect on splicing. According to the American College of Medical Genetics (ACMG) guidelines, this variant was classified as likely pathogenic. CONCLUSION: This study highlights the phenotypic heterogeneity within the same family, reports the occurrence of renal failure and adverse pregnancy outcomes in a female patient at reproductive age with BOR syndrome, and enriches the mutational spectrum of pathogenic variants in the EYA1 gene.
Assuntos
Síndrome Brânquio-Otorrenal , Surdez , Perda Auditiva Neurossensorial , Perda Auditiva , Insuficiência Renal , Humanos , Gravidez , Feminino , Síndrome Brânquio-Otorrenal/genética , Síndrome Brânquio-Otorrenal/patologia , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas Tirosina Fosfatases/genética , Perda Auditiva/genética , Linhagem , Proteínas Nucleares/genéticaRESUMO
Efficient oxygen evolution reaction electrocatalysts are essential for sustainable clean energy conversion. However, catalytic materials followed the conventional adsorbate evolution mechanism (AEM) with the inherent scaling relationship between key oxygen intermediates *OOH and *OH, or the lattice-oxygen-mediated mechanism (LOM) with the possible lattice oxygen migration and structural reconstruction, which are not favorable to the balance between high activity and stability. Herein, we propose an unconventional Co-Fe dual-site segmentally synergistic mechanism (DSSM) for single-domain ferromagnetic catalyst CoFeSx nanoclusters on carbon nanotubes (CNT) (CFS-ACs/CNT), which can effectively break the scaling relationship without sacrificing stability. Co3+ (L.S, t2g6eg0) supplies the strongest OH* adsorption energy, while Fe3+ (M.S, t2g4eg1) exposes strong O* adsorption. These dual-sites synergistically produce of Co-O-O-Fe intermediates, thereby accelerating the release of triplet-state oxygen ( ↑ O = O ↑ ). As predicted, the prepared CFS-ACs/CNT catalyst exhibits less overpotential than that of commercial IrO2, as well as approximately 633 h of stability without significant potential loss.
RESUMO
Global terrestrial ecosystems are simultaneously threatened by multiple environmental pressures, with microplastics (MPs) pollution and drought possibly being the most pressing, both of which may have unanticipated effects on soil organisms. Here, we investigated the responses of diversity, composition and functions of soil bacterial community to MPs pollution (including two MPs types: polyethylene (PE) and polylactic acid (PLA); two MPs sizes: < 20 µm and <300 µm) and drought in microcosms. We found that only 20 µm PLA MPs significantly decreased soil bacterial diversity by 17.4 % and altered soil bacterial community composition, while PE MPs and 300 µm PLA MPs had no significant effects. The copiotrophic bacteria (i.e., Proteobacteria and Firmicutes) were enriched in the 20 µm PLA MPs pollution soils due to the enhanced dissolved organic carbon contents. Moreover, our results showed that the 20 µm PLA MPs also affected the potential phenotypes and functions of soil bacterial community, increasing the potentially pathogenic, stress-tolerant, containing mobile elements and forming biofilms phenotypes, and promoting membrane transport and signal transduction pathways. These results suggested that the effects of MPs on soil bacterial community varied depending on MPs types and sizes. However, drought significantly increased soil bacterial diversity by 10.3 % and affected soil bacterial community composition in the 20 µm PLA MPs pollution soils. We also found that drought inhibited the levels of potentially pathogenic, containing mobile elements and forming biofilms phenotypes in the 20 µm PLA MPs pollution soils. Taken together, these findings reveal that drought may alleviate the adverse effects of MPs pollution on soil bacterial community, which enhances our understanding of the interactive effects of multiple global change factors on agroecosystem functions.
Assuntos
Secas , Ecossistema , Microplásticos , Plásticos/toxicidade , Bactérias , Poliésteres , Polietileno , Solo , Microbiologia do SoloRESUMO
Soil ecosystems are under considerable pressure due to anthropogenic factors, including microplastics (MPs) pollution and drought. However, little is known about the interactive effects of MPs and drought on soil organisms, especially soil micro-food web. We conducted a microcosm experiment with MPs pollution (including two types and two sizes of MPs) and drought to investigate their interaction effects on soil microbial, protist, and nematode communities in soil micro-food web. We found that MPs significantly decreased the complexity and stability of soil micro-food web, with greater negative effects of biodegradable and smaller-sized MPs than conventional and larger-sized MPs. Drought had negative effects on soil micro-food web in the non-MPs pollution soils while increasing the complexity and stability of soil micro-food web in the MPs pollution soils. Drought increased the proportion of negative correlations between bacteria and fungi in the biodegradable MPs soils while decreasing the proportion of negative correlations between protists and nematodes in the smaller-sized MPs soils. Our study reveals that drought may alleviate the negative effects of MPs on soil micro-food web by reducing competition among lower trophic levels in the biodegradable MPs pollution soils while reducing competition among higher trophic levels in the smaller-sized MPs pollution soils.
RESUMO
Biofilm-associated infections exert more severe and harmful attacks on human health since they can accelerate the generation and development of the antibiotic resistance of the embedded bacteria. Anti-biofilm materials and techniques that can eliminate biofilms effectively are in urgent demand. Therefore, we designed a type I photosensitizer (TTTDM) with an aggregation-induced emission (AIE) property and used F-127 to encapsulate the TTTDM into nanoparticles (F-127 AIE NPs). The NPs exhibit highly efficient ROS generation by enhancing intramolecular D-A interaction and confining molecular non-radiative transitions. Furthermore, the NPs can sufficiently penetrate the biofilm matrix and then detect and eliminate mature bacterial biofilms upon white light irradiation. This strategy holds great promise for the rapid detection and eradication of bacterial biofilms.
Assuntos
Nanopartículas , Fotoquimioterapia , Humanos , Fármacos Fotossensibilizantes/farmacologia , Fotoquimioterapia/métodos , Luz , Bactérias , Biofilmes , Antibacterianos/farmacologiaRESUMO
The GJB2 gene is the most common gene responsible for hearing loss (HL) worldwide, and missense variants are the most abundant type. GJB2 pathogenic missense variants cause nonsyndromic HL (autosomal recessive and dominant) and syndromic HL combined with skin diseases. However, the mechanism by which these different missense variants cause the different phenotypes is unknown. Over 2/3 of the GJB2 missense variants have yet to be functionally studied and are currently classified as variants of uncertain significance (VUS). Based on these functionally determined missense variants, we reviewed the clinical phenotypes and investigated the molecular mechanisms that affected hemichannel and gap junction functions, including connexin biosynthesis, trafficking, oligomerization into connexons, permeability, and interactions between other coexpressed connexins. We predict that all possible GJB2 missense variants will be described in the future by deep mutational scanning technology and optimizing computational models. Therefore, the mechanisms by which different missense variants cause different phenotypes will be fully elucidated.
RESUMO
Due to non-specific strong nano-bio interactions, it is difficult for nanocarriers with permanent rough surface to cross multiple biological barriers to realize efficient drug delivery. Herein, a camouflaged virus-like-nanocarrier with a transformable rough surface is reported, which is composed by an interior virus-like mesoporous SiO2 nanoparticle with a rough surface (vSiO2 ) and an exterior acid-responsive polymer. Under normal physiological pH condition, the spikes on vSiO2 are hidden by the polymer shell, and the non-specific strong nano-bio interactions are effectively inhibited. While in the acidic tumor microenvironment, the nanocarrier sheds the polymer camouflage to re-expose its rough surface. So, the retention ability and endocytosis efficiency of the nanocarrier are great improved. Owing to it's the dynamically variable rough surface, the rationally designed nanocarrier exhibits extended blood-circulation-time and enhanced tumor accumulation.
Assuntos
Portadores de Fármacos , Nanopartículas , Dióxido de Silício , Sistemas de Liberação de Medicamentos , Polímeros , Doxorrubicina/farmacologia , Linhagem Celular TumoralRESUMO
Identification the sources of heavy metals can effectively control and prevent agricultural soil pollution. Here we performed a three-year mass balance study along a gradient of soil pollution near a smelter to quantify the potential contribution and net cadmium (Cd) fluxes and predict Cd concentration in rice grains by multiple regression (MR) and back propagation (BP) neural network. The Cd inputs were mainly from the irrigation water (54.6-60.8%) in the moderately polluted and background sites but from atmospheric deposition (90.9%) in the highly polluted site. The Cd outputs were mainly from the surface runoff (55.8-59.5%) in the moderately polluted and background sites, but from Sedum plumbizincicola phytoextraction (83.6%) in the highly polluted site. The soil Cd concentrations, the annual fluxes of atmospheric deposition, pesticides and fertilizers, irrigation water, surface runoff, and leaching water were selected as the dependent factors to predict Cd concentrations in rice grains. The genetic algorithms (GA)-BP neural network model gives the best prediction accuracy compared to the BP neural network model and multivariate regression analysis. The major implication is that the health risks through the consumption of rice can be rapidly assessed based on the Cd concentrations in rice grains predicted by the model.
Assuntos
Oryza , Poluentes do Solo , Cádmio/análise , Cobre/análise , Poluentes do Solo/análise , Solo , Água/análiseRESUMO
BACKGROUND: Less is known regarding the association of pulse pressure (PP) with memory function. This study aimed to characterize long-term patterns of PP in middle-aged and older adults and explore their impact on subsequent change in memory function. METHODS: Data from the English Longitudinal Study of Ageing (ELSA, 2004-2018), were analyzed. Totally, 3587 dementia-free participants with three measurements of BP were included. All three visits of PP (2004-2012) were used to characterize longitudinal patterns of PP by group-based trajectory modeling (GBTM). Generalized estimating equation (GEE) models were fitted to explore the impact of PP trajectories on change in memory over a subsequent 6-year period (2012-2018). RESULTS: Using GBTM, three distinct trajectories of PP were identified: low-stable (38.1%), moderate-stable (48.6%), and elevated-increasing group (13.3%). GEE model suggested that memory declined over a 6-year period in all PP trajectories (all Ptime <0.001). The overall interactions between patterns of PP changes and time with memory were statistically significant (χ2 interaction = 20.69, p = 0.002). Compared to participants in the low-stable group, those in the moderate-stable and elevated-increasing group exhibited a faster decline in memory. CONCLUSIONS: Longitudinal patterns of moderate-stable and elevated-increasing PP were associated with an accelerated decrease in memory. Controlling BP instability may be a promising interventional strategy for preventing cognitive decline among older adults.
Assuntos
Envelhecimento , Disfunção Cognitiva , Humanos , Pessoa de Meia-Idade , Idoso , Pressão Sanguínea , Estudos Longitudinais , Envelhecimento/psicologia , Transtornos da MemóriaRESUMO
BACKGROUND: In camels, nasopharyngeal myiasis is caused by the larvae of Cephalopina titillator, which parasitize the tissues of nasal and paranasal sinuses, pharynx, and larynx. C. titillator infestation adversely affects the health of camels and decreases milk and meat production and even death. However, the C. titillator infestation in Bactrian camels has not been widely studied. METHODS: The present study was conducted to determine the prevalence and risk factors of C. titillator in Bactrian camels of northwestern Xinjiang. Suspected larvae recovered from infested camels were evaluated for C. titillator by microscopy and polymerase chain reaction. Nucleotide sequences of the partial mitochondrial cytochrome c oxidase subunit I (COX1) and cytochrome b (CYTB) genes from the C. titillator of camels were aligned from the NCBI database. Furthermore, the gross and histopathological alterations associated with C. titillator infestation were evaluated via pathological examination. RESULTS: Of 1263 camels examined 685 (54.2%) camels were infested with suspected C. titillator larvae. Different larval stages were topically detected in the nasal passages and pharynx of the camel heads. Microscopy analysis of the pharyngeal mucosa tissue revealed necrotic tissue debris and some inflammatory cells. Molecular detection of the larval COX1 and CYTB genes indicated that pathogen collected in Bactrian camels was C. titillator. The epidemiological study demonstrated that the prevalence rate of C.titillator infestation was significantly higher in camels of Bestierek Town Pasture (67.2%) and Karamagai Town Pasture (63.6%) compared to Kitagel Town Pasture (38.7%) and Qibal Town Pasture (35.8%) (P < 0.05). No significant difference was observed between the prevalence rates in male (52.6%) and female (54.6%) camels (P > 0.05). The prevalence was higher in warm (64.2%) than that in cold (48.4%) seasons (P < 0.001). The prevalence in camels with non-nomadic method (67.2%) was significantly higher than in animals with nomadic method (47.5%) (P < 0.001). The prevalence of C.titillator infestation was significantly higher in animals of aged 5-10 (60.1%) and aged > 10 (61.1%) years old compared to those of aged < 5 (31.7%) years old camels (P < 0.001). CONCLUSION: Our results confirm that there is a high prevalence of C. titillator in Bactrian camels from Xinjiang, closely related to age, season, pasture environment, and husbandry methods. Developing prevention, diagnosis, and control programs to prevent transmission is necessary.
Assuntos
Dípteros , Miíase , Animais , Camelus , China/epidemiologia , Citocromos b , Complexo IV da Cadeia de Transporte de Elétrons , Feminino , Larva , Masculino , Miíase/epidemiologia , Miíase/veterinária , PrevalênciaRESUMO
Platycodon grandiflorus is a well-known and widely distributed traditional herbal medicine and functional food in Asia, with triterpenoids as the main bioactive component in its roots. Acetyl-CoA C-acetyltransferase (AACT) is the initiation enzyme in the mevalonate pathway and plays an important role in the biosynthesis of terpenoids. OBJECTIVE: The objective of this study was to clone and identify the PgAACT function in P. grandiflorus. METHODS: The full-length sequence of PgAACT genes was isolated and cloned from P. grandiflorus by polymerase chain reaction (PCR). The recombinant plasmid was constructed using the pET-32a vector and expressed in E. coli Transetta (DE3) cells. Subcellular localization of AACT was observed in the epidermal cells of N. tabacum. Quantitative reverse transcription-PCR (qRT-PCR) was used to identify the PgAACT gene transcription levels. After MeJA treatment, the changes in AACT gene expression were observed, and UHPLC-Q-Exactive Orbitrap MS/MS was used to detect the changes in P. grandiflorus saponins. RESULTS: In this study, two full-length cDNAs encoding AACT1 (PgAACT1) and AACT2 (PgAACT2) were isolated and cloned from P. grandiflorus. The deduced PgAACT1 and PgAACT2 proteins contain 408 and 416 amino acids, respectively. The recombinant vectors were constructed, and the protein expression was improved by optimizing the reaction conditions. Sodium dodecyl sulphate-polycrylamide gel electrophloresis and western blot analysis showed that the PgAACT genes were successfully expressed, with molecular weights of the recombinant proteins of 61 and 63 kDa, respectively. Subcellular localization showed that the PgAACT genes were localized in the cytoplasm. Tissue specificity analysis of P. grandiflorus from different habitats showed that PgAACT genes were expressed in the roots, stems, and leaves. After MeJA treatment, the expression level of PgAACT genes and the content of total saponins of P. grandiflorus were significantly increased, suggesting that PgAACT genes play an important role in regulating plant defense systems. CONCLUSION: Cloning, expression, and functional analysis of PgAACT1 and PgAACT2 will be helpful in understanding the role of these two genes in terpene biosynthesis.
Assuntos
Platycodon , Saponinas , Platycodon/genética , Platycodon/metabolismo , Acetil-CoA C-Acetiltransferase/genética , Acetil-CoA C-Acetiltransferase/metabolismo , DNA Complementar/genética , Regulação da Expressão Gênica de Plantas , Escherichia coli/genética , Espectrometria de Massas em Tandem , Clonagem Molecular , TerpenosRESUMO
Refractory carbides are attractive candidates for support materials in heterogeneous catalysis because of their high thermal, chemical, and mechanical stability. However, the industrial applications of refractory carbides, especially silicon carbide (SiC), are greatly hampered by their low surface area and harsh synthetic conditions, typically have a very limited surface area (<200 m2 g-1), and are prepared in a high-temperature environment (>1,400 °C) that lasts for several or even tens of hours. Based on Le Chatelier's principle, we theoretically proposed and experimentally verified that a low-pressure carbothermal reduction (CR) strategy was capable of synthesizing high-surface area SiC (569.9 m2 g-1) at a lower temperature and a faster rate (â¼1,300 °C, 50 Pa, 30 s). Such high-surface area SiC possesses excellent thermal stability and antioxidant capacity since it maintained stability under a water-saturated airflow at 650 °C for 100 h. Furthermore, we demonstrated the feasibility of our strategy for scale-up production of high-surface area SiC (460.6 m2 g-1), with a yield larger than 12 g in one experiment, by virtue of an industrial viable vacuum sintering furnace. Importantly, our strategy is also applicable to the rapid synthesis of refractory metal carbides (NbC, Mo2C, TaC, WC) and even their emerging high-entropy carbides (VNbMoTaWC5, TiVNbTaWC5). Therefore, our low-pressure CR method provides an alternative strategy, not merely limited to temperature and time items, to regulate the synthesis and facilitate the upcoming industrial applications of carbide-based advanced functional materials.
RESUMO
Surface porous Ti substrates were obtained by electrodeposition-hot melt-alkali etching. Porous-Ti/BDD and flat-Ti/BDD electrodes were prepared for comparative study. The results of SEM, Raman, and XRD analyses show that the BDD films of these two electrodes had good uniformity and stable quality. The electrochemical window (EW) and electrochemical-active surface area (EASA) of the porous-Ti/BDD electrode is as high as 4.21 V and 22.78 cm2 (11.39 cm2/cm2), respectively. Furthermore, the electrochemical catalytic performance and degradation mechanism of porous-Ti/BDD electrode as the anode were studied by the electrolysis of Active Orange dye X-GN (X-GN), and the optimal electrochemical degradation operating parameters were obtained. The results show that when the degradation time was 50 min, the X-GN was completely decolorized. The TOC removal rate reached 69.24%, and the energy consumption was 5.62 kWh m-3. The contribution rate of â¢OH and SO4â¢- was calculated to be 91.40% and 1.26% by radical quenching experiments, respectively, indicating that the active substances in the degradation system were mainly â¢OH and SO4â¢-. The high specific surface characteristics of porous-Ti/BDD electrode enhanced its electrochemical oxidation advantages, and it showed a high degradation efficiency and low energy consumption for the treatment of X-GN simulated wastewater.
Assuntos
Águas Residuárias , Poluentes Químicos da Água , Álcalis , Compostos Azo , Boro/química , Eletrodos , Oxirredução , Porosidade , Águas Residuárias/química , Poluentes Químicos da Água/análiseRESUMO
Platycodon grandiflorus, a perennial flowering plant widely distributed in China and South Korea, is an excellent resource for both food and medicine. The main active compounds of P. grandiflorus are triterpenoid saponins. WRKY transcription factors (TFs) are among the largest gene families in plants and play an important role in regulating plant terpenoid accumulation, physiological metabolism, and stress response. Numerous studies have been reported on other medicinal plants; however, little is known about WRKY genes in P. grandiflorus. In this study, 27 PgWRKYs were identified in the P. grandiflorus transcriptome. Phylogenetic analysis showed that PgWRKY genes were clustered into three main groups and five subgroups. Transcriptome analysis showed that the PgWRKY gene expression patterns in different tissues differed between those in Tongcheng City (Southern Anhui) and Taihe County (Northern Anhui). Gene expression analysis based on RNA sequencing and qRT-PCR analysis showed that most PgWRKY genes were expressed after induction with methyl jasmonate (MeJA). Co-expressing PgWRKY genes with triterpenoid biosynthesis pathway genes revealed four PgWRKY genes that may have functions in triterpenoid biosynthesis. Additionally, functional annotation and protein-protein interaction analysis of PgWRKY proteins were performed to predict their roles in potential regulatory networks. Thus, we systematically analyzed the structure, evolution, and expression patterns of PgWRKY genes to provide an important theoretical basis for further exploring the molecular basis and regulatory mechanism of WRKY TFs in triterpenoid biosynthesis.
Assuntos
Platycodon , Triterpenos , Acetatos , Ciclopentanos , Regulação da Expressão Gênica de Plantas/genética , Oxilipinas , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Platycodon/genética , Platycodon/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transcriptoma/genéticaRESUMO
Constructing hierarchical three-dimensional (3D) mesostructures with unique pore structure, controllable morphology, highly accessible surface area, and appealing functionality remains a great challenge in materials science. Here, we report a monomicelle interface confined assembly approach to fabricate an unprecedented type of 3D mesoporous N-doped carbon superstructure for the first time. In this hierarchical structure, a large hollow locates in the center (â¼300 nm in diameter), and an ultrathin monolayer of spherical mesopores (â¼22 nm) uniformly distributes on the hollow shells. Meanwhile, a small hole (4.0-4.5 nm) is also created on the interior surface of each small spherical mesopore, enabling the superstructure to be totally interconnected. Vitally, such interconnected porous supraparticles exhibit ultrahigh accessible surface area (685 m2 g-1) and good underwater aerophilicity due to the abundant spherical mesopores. Additionally, the number (70-150) of spherical mesopores, particle size (22 and 42 nm), and shell thickness (4.0-26 nm) of the supraparticles can all be accurately manipulated. Besides this spherical morphology, other configurations involving 3D hollow nanovesicles and 2D nanosheets were also obtained. Finally, we manifest the mesoporous carbon superstructure as an advanced electrocatalytic material with a half-wave potential of 0.82 V (vs RHE), equivalent to the value of the commercial Pt/C electrode, and notable durability for oxygen reduction reaction (ORR).