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In this work, an effective strategy for the large-scale fabrication of highly porous CuO/Cu2O/Cu/carbon (P-Cu-C) has been established. Cu-cross-linked aerogels were first continuously prepared using a continuous flow mode to form uniform beads, which were transformed into P-Cu-C with a subsequent pyrolysis process. Various pyrolysis temperatures were used to form a series of P-Cu-C including P-Cu-C-250, P-Cu-C-200, P-Cu-C-350, and P-Cu-C-450 to investigate suitable pyrolysis conversion processes. The obtained P-Cu-C series were utilized as anodes of lithium-ion batteries, in which P-Cu-C-250 exhibited a higher reversible gravimetric capacity, excellent rate capability, and superior cycle stability. The enhanced behavior of P-Cu-C-250 was benefitted from the synergistic interaction between uniformly dispersed CuO, Cu2O, Cu nanoparticles, and highly graphitized carbon with a large surface area and highly porous structure. More importantly, the preparation of P-Cu-C-250 could be scaled up by taking advantage of the continuous flow synthesis mode, which may provide pilot- or industrial-scale applications. The large-scale fabrication proposed here may give a universal method to fabricate highly porous metal oxide-carbon anode materials for electrochemical energy conversion and storage applications. Porous CuO/Cu2O/Cu/carbon derived from Cu-crosslinked aerogels was used as Li-ion battery anode materials, exhibiting a high reversible areal capacity, large gravimetric capacity, superior cycling performance, and excellent rate capacity. A continuous preparation method is established to ensure the product scaled up.
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Thioesters make up an important class of bioactive compounds. Due to their chemoselectivity, they have been widely used in the synthesis of a wide range of complex bioactive molecules and natural products. At present, chemists have developed a variety of methods for the preparation of thioester compounds. However, these methods usually require the use of transition metal catalysis or harsh reaction conditions. The strategy of synthesizing thioester compounds via visible light-induced electron donor-acceptor (EDA) complex reactions avoids the problems associated with conventional methods through the development of photocatalysis. Here we report a sustainable method for thiocarbonylating aryl sulfonium salts via a visible light-induced EDA complex process without transition metals.
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Interferon-gamma (IFN-γ) is an inflammatory cytokine that plays a crucial role in regulating both innate and cell-mediated immune responses by binding to a receptor complex made up of IFNGR1 and IFNGR2. In this study, the complete cDNA of IFN-γ and IFNGR1 from Nibea albiflora were cloned and functionally characterized (named NaIFN-γ and NaIFNGR1), whose complete cDNA sequences were 1593 bp and 2792 bp, encoding 201 and 399 amino acids, respectively. Multiple sequence alignment and phylogenetic analysis showed that the concluded amino acids sequences of NaIFN-γ and NaIFNGR1 shared high identity with their teleost orthologues including the IFN-γ signature and nuclear localization signal (NLS) motif in NaIFN-γ and FN ⠢ domain in NaIFNGR1. Real-time PCR showed that NaIFN-γ and NaIFNGR1 constitutively expressed in all tested tissues, such as the head-kidney, spleen, liver, kidney, gill, muscle, blood, and intestine with the highest expression of NaIFN-γ and NaIFNGR1 appearing in the liver and gill, respectively. After experiencing stimulation with Polyinosinic-polycytidylic acid (Poly (I:C)), Vibrio alginolyticus (V. alginolyticus) or Vibrio parahaemolyticus (V. parahaemolyticus), NaIFN-γ and NaIFNGR1 mRNA were up-regulated with the time-dependent model. Due to the presence of a nuclear localization signal (NLS), the subcellular localization revealed that NaIFN-γ dispersed throughout the cytoplasm and nucleus. NaIFNGR1, as a member of Cytokine receptor family B, was primarily expressed on the cell membrane. When NaIFN-γ and NaIFNGR1 were co-transfected, their fluorescence signals overlapped on the membrane of HEK 293T cells indicating the potential interaction between IFN-γ and IFNGR1. The GST-pull-down results further showed that NaIFN-γ could directly interact with the extracellular region of NaIFNGR1, further confirming the affinity between IFN-γ and IFNGR1. Taken together, the results firstly demonstrated that the NaIFN-γ ligand-receptor system existed in N.albiflora and played a pivotal part in N.albiflora's immune response against pathogenic bacterial infections, which contributed to the better understanding of the role of IFN-γ in the immunomodulatory mechanisms of teleost.
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Interferón gamma , Perciformes , Animales , Señales de Localización Nuclear/genética , Secuencia de Aminoácidos , Filogenia , ADN Complementario , Aminoácidos/genéticaRESUMEN
In this study, the synthesis of Cu-MOF-199@multiwalled carbon nanotubes (Cu-MOF-199@MWCNTs) composites was achieved and utilized to create an advanced electrochemical sensor for creatinine (Cre) detection. The composites were modified on a glassy carbon electrode surface through direct drip coating, followed by the deposition of copper nanoparticles (CuNPs) via constant potential deposition. Characterized by various techniques and electrochemical analyses, the Cu-MOF-199@MWCNTs composite increased the CuNPs load, improving the detection sensitivity for Cre. Under optimal conditions, the modified electrode exhibited good linearity across a broad range of Cre concentrations (0.05-40.0 µM) with a low detection limit of 11.3 nM. The developed sensor demonstrated remarkable stability, reproducibility, and selectivity, showing promise in sensitive and accurate Cre detection in serum samples.
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Cobre , Nanotubos de Carbono , Creatinina , Reproducibilidad de los ResultadosRESUMEN
Herein, we present a decarboxylative thiocarbonylation of aryl and alkenyl sulfonium salts with oxalic acid monothioethers (OAMs), which can be achieved by visible light-accelerated palladium catalysis. Sulfonium salts are widely available, and OAM is an easily accessible and stored reagent; this mild reaction method can also be used for the synthesis of different types of thioester compounds. The reaction represents a new application of visible light-accelerated palladium catalysis in catalytic decarboxylative cross-couplings.
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Tumor necrosis factor α (TNFα), a cytokine mainly secreted by active macrophages and monocytes, causes hemorrhagic necrosis of tumor tissues, kills tumor cells, regulates inflammatory responses, and plays a crucial role in innate immunity. In this study, TNFα of Sepiella japonica (named as SjTNFα) was acquired, whose full-length cDNA was 1206 bp (GenBank accession no. ON357428), containing a 5' UTR of 185 bp, a 3' UTR of 137 bp and an open reading frame (ORF) of 1002bp to encode a putative peptide of 333 amino acids for constructing the transmembrane domain and the cytoplasmic TNF domain. Its predicted pI was 8.69 and the theoretical molecular weight was 44.72 KDa. Multiple sequence alignment and phylogenetic analysis showed that SjTNFα had the highest homology to Octopus sinensis, they fell into a unified branch and further clustered with other animals. Real-time PCR indicated that SjTNFα was widely expressed in all subject tissues, including spleen, pancreas, gill, heart, brain, optic lobe, liver and intestine, and exhibited the highest in the liver and the lowest in the brain. The relative expression of SjTNFα varied at the developmental period of juvenile stage, pre-spawning and oviposition in the squid, with the highest in the liver at the juvenile stage and oviposition, and in the optic lobe of pre-spawning. After being infected with Vibrio parahaemolyticus and Aeromonas hydrophila, the expression of SjTNFα in liver and gill were both upregulated with time, and the highest expression appeared at 24 h and 8 h in liver for different infection, and at 4 h in gill consistently. Cell localization showed that SjTNFα distributed on membrane of HEK293 cells because it was a type II soluble transmembrane protein. When HEK293 cells were stimulated with LPS of different concentrations, the NF-κB pathway was activated in the nucleus and the corresponding mRNA was transferred through the intracellular signal transduction pathway, resulting in the synthesis and release of TNFα, which made the expression of SjTNFα was up-regulated obviously. These findings showed that SjTNFα might play an essential role in the defense of S. japonica against bacteria challenge, which contributed to the understanding of the intrinsic immune signaling pathway of Cephalopoda and the further study of host-pathogen interactions.
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Decapodiformes , Factor de Necrosis Tumoral alfa , Femenino , Animales , Humanos , Factor de Necrosis Tumoral alfa/genética , Secuencia de Aminoácidos , Secuencia de Bases , Filogenia , Células HEK293 , Decapodiformes/genética , Clonación Molecular , Regulación de la Expresión GénicaRESUMEN
The thawing of dormant plateau permafrost emits nitrous oxide (N2O) through wetlands; however, the N2O production mechanism in plateau wetlands is still unclear. Here, we used the 15N-18O double tracer technique and metagenomic sequencing to analyze the N2O production mechanism in the Yunnan-Kweichow and Qinghai-Tibet plateau wetlands during the summer of 2020. N2O production activity was detected in all 16 sediment samples (elevation 1020-4601 m: 2.55 ± 0.42-26.38 ± 3.25 ng N g-1 d-1) and was promoted by nitrifier denitrification (ND). The key functional genes of ND (amoA, hao, and nirK) belonged to complete ammonia oxidizing (comammox) bacteria, and the key ND species was the comammox bacterium Nitrospira nitrificans. We found that the comammox bacterial species N. nitrificans and the ammonia oxidizing bacterial (AOB) species Nitrosomonas europaea cooperate to produce N2O in the plateau wetland sediments. Furthermore, we inferred that environmental factors (elevation and total organic matter (TOM)) influence the cooperation pattern via N. nitrificans, thus affecting the N2O production activity in the plateau wetland sediments. Our findings advance the mechanistic understanding of nitrifiers in biogeochemical cycles and global climate change.
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Archaea , Óxido Nitroso , Óxido Nitroso/análisis , Humedales , Amoníaco , Oxidación-Reducción , China , Bacterias/genética , Nitrificación , Microbiología del SueloRESUMEN
Eutrophication is one of the major threats to the inland water ecosystem. Satellite remote sensing provides a promising way to monitor trophic state at large spatial scale in an efficient manner. Currently, most satellite-based trophic state evaluation approaches have focused on water quality parameters retrieval (e.g., transparency, chlorophyll-a), based on which trophic state was evaluated. However, the retrieval accuracies of individual parameter do not meet the demand for accurate trophic state evaluation, especially for the turbid inland waters. In this study, we proposed a novel hybrid model to estimate trophic state index (TSI) by integrating multiple spectral indices associated with different eutrophication level based on Sentinel-2 imagery. The TSI estimated by the proposed method agreed well with the in-situ TSI observations, with root mean square error (RMSE) of 6.93 and mean absolute percentage error (MAPE) of 13.77%. Compared with the independent observations from Ministry of Ecology and Environment, the estimated monthly TSI also showed good consistency (RMSE=5.91,MAPE=10.66%). Furthermore, the congruent performance of the proposed method in the 11 sample lakes (RMSE=5.91,MAPE=10.66%) and the 51 ungauged lakes (RMSE=7.16,MAPE=11.56%) indicated the favorable model generalization. The proposed method was then applied to assess the trophic state of 352 permanent lakes and reservoirs across China during the summers of 2016-2021. It showed that 10%, 60%, 28%, and 2% of the lakes/reservoirs are in oligotrophic, mesotrophic, light eutrophic, and middle eutrophic states respectively. Eutrophic waters are concentrated in the Middle-and-Lower Yangtze Plain, the Northeast Plain, and the Yunnan-Guizhou Plateau. Overall, this study improved the trophic state representativeness and revealed trophic state spatial distribution of Chinese inland waters, which has the significant meanings for aquatic environment protection and water resource management.
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Ecosistema , Monitoreo del Ambiente , Monitoreo del Ambiente/métodos , China , Clorofila A , Calidad del Agua , Lagos , EutrofizaciónRESUMEN
OBJECTIVE: Hypertension is one of the leading causes of human death and disability. MTHFR and MTRR regulate folate metabolism and are closely linked to hypertension, although the relationship is inconsistent among different ethnic groups. The present study aims to investigate the effects of MTHFR C677T (rs1801133), MTHFR A1298C (rs1801131), and MTRR A66G (rs1801394) polymorphisms on hypertension susceptibility in the Bai nationality of the Yunnan Province, China. METHODS: This case-control study included 373 hypertensive patients and 240 healthy controls from the Chinese Bai population. The genotyping of MTHFR and MTRR gene polymorphisms was carried out by using the KASP method. The effects of genetic variations of MTHFR and MTRR genes on hypertension risk were evaluated with odds ratios (OR) and 95% confidence intervals (95% CI). RESULTS: The present study revealed that the CT and TT genotypes and T allele of MTHFR C677T locus were considerably associated with an increased risk of hypertension. In addition, MTHFR A1298C locus CC genotype could significantly increase the hypertension risk. The T-A and C-C haplotypes of MTHFR C677T and MTHFR A1298C could increase the risk of hypertension. Further stratified analysis by risk rank of folate metabolism indicated that people with poor utilization of folic acid were more prone to develop hypertension. In the hypertension group, the MTHFR C677T polymorphism was significantly associated with fasting blood glucose, fructosamine, apolipoprotein A1, homocysteine, superoxide dismutase, and malondialdehyde levels. CONCLUSION: Our study suggested that genetic variations of MTHFR C677T and MTHFR A1298C were significantly associated with susceptibility to hypertension in the Bai population from Yunnan, China.
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Predisposición Genética a la Enfermedad , Hipertensión , Humanos , Estudios de Casos y Controles , China/epidemiología , Ácido Fólico/metabolismo , Genotipo , Hipertensión/genética , Metilenotetrahidrofolato Reductasa (NADPH2)/genética , Polimorfismo Genético , Polimorfismo de Nucleótido SimpleRESUMEN
A facile and novel Ce-MOF@MWCNTs@ZnO-modified glassy carbon electrode was prepared through drop coating and used for accurate and sensitive electrochemical detection of carbendazim. The modification of ZnO nanospheres and Ce-based metal-organic frameworks (Ce-MOFs), which possess vast surface/bulk ratio, large surface area, and excellent catalytic ability, provided more active sites for reaction. The combination of multi-walled carbon nanotubes endowed the modified electrode with excellent conductivity and greatly accelerated the electron transfer. The promotion of electrochemical response and the significant improvement of peak current indicated the outstanding electrocatalytic ability of the modified electrode. The oxidation peak current of carbendazim which was measured by DPV in a potential range from 0.5 to 1.0 V produced a good linear relationship in the concentration ranges 0.05-10.0 µM and 10.0-50.0 µM under optimized experimental conditions. The detection limit was 13.2 nM (S/N = 3). The constructed electrode was successfully applied to the detection of carbendazim in Lithospermum and Glycyrrhiza uralensis real samples and exhibited satisfactory RSD (2.7-3.6% and 1.6-4.8%, respectively) and recovery (102-106% and 97.7-107%, respectively).
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Medicamentos Herbarios Chinos , Nanocompuestos , Nanotubos de Carbono , Óxido de Zinc , Técnicas Electroquímicas , Nanocompuestos/química , Nanotubos de Carbono/química , Medicamentos Herbarios Chinos/análisisRESUMEN
Chronic pain is an enormous modern public health problem, with significant numbers of people debilitated by chronic pain from a variety of etiologies. Translocator protein 18 kDa (TSPO) was discovered in 1977 as a peripheral benzodiazepine receptor. It is a five transmembrane domain protein, mainly localized in the outer mitochondrial membrane. Recent and increasing studies have found changes in TSPO and its ligands in various chronic pain models. Reversing their expressions has been shown to alleviate chronic pain in these models, illustrating the effects of TSPO and its ligands. Herein, we review recent evidence and the mechanisms of TSPO in the development of chronic pain associated with peripheral nerve injury, spinal cord injury, cancer, and inflammatory responses. The cumulative evidence indicates that TSPO-based therapy may become an alternative strategy for treating chronic pain.
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Dolor Crónico , Receptores de GABA , Proteínas Portadoras/metabolismo , Dolor Crónico/tratamiento farmacológico , Dolor Crónico/metabolismo , Humanos , Ligandos , Membranas Mitocondriales/metabolismo , Receptores de GABA/metabolismoRESUMEN
BACKGROUND: Microfluidic chip detection technology is considered a potent tool for many bioanalytic applications. Rapid detection of foodborne pathogens in the early stages is imperative to prevent the outbreak of foodborne diseases, known as a severe threat to human health. Conventional bacterial culture methods for detecting foodborne pathogens are time-consuming, laborious, and lacking in pathogen diagnosis. To overcome this problem, we have created an embedded paper-based microchip based on isothermal loop amplification (LAMP), which can rapidly and sensitively detect foodborne pathogens. RESULTS: We embed paper impregnated with LAMP reagent and specific primers in multiple reaction chambers of the microchip. The solution containing the target pathogen was injected into the center chamber and uniformly distributed into the reaction chamber by centrifugal force. The purified DNA of Escherichia coli O157:H7, Salmonella spp., Staphylococcus aureus, and Vibrio parahaemolyticus has been successfully amplified and directly detected on the microchip. The E. coli O157:H7 DNA was identified as low as 0.0134 ng µL- 1. Besides, the potential of this microchip in point-of-care testing was further tested by combining the on-chip sample purification module and using milk spiked with Salmonella spp.. The pyrolyzed milk sample was filtered through a polydopamine-coated paper embedded in the inside of the sample chamber. It was transported to the reaction chamber by centrifugal force for LAMP amplification. Then direct chip detection was performed in the reaction chamber embedded with calcein-soaked paper. The detection limit of Salmonella spp. in the sample measured by the microchip was approximately 12 CFU mL- 1. CONCLUSION: The paper embedded LAMP microchip offers inexpensive, user-friendly, and highly selective pathogen detection capabilities. It is expected to have great potential as a quick, efficient, and cost-effective solution for future foodborne pathogen detection.
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Microbiología de Alimentos/métodos , Enfermedades Transmitidas por los Alimentos/microbiología , Dispositivos Laboratorio en un Chip , Técnicas de Diagnóstico Molecular/instrumentación , Técnicas de Amplificación de Ácido Nucleico/instrumentación , Papel , Enfermedades Transmitidas por los Alimentos/prevención & controlRESUMEN
Nitrogen (N) is a major driving force for crop yield improvement, but application of high levels of N delays flowering, prolonging maturation and thus increasing the risk of yield losses. Therefore, traits that enable utilization of high levels of N without delaying maturation will be highly desirable for crop breeding. Here, we show that OsNRT1.1A (OsNPF6.3), a member of the rice (Oryza sativa) nitrate transporter 1/peptide transporter family, is involved in regulating N utilization and flowering, providing a target to produce high yield and early maturation simultaneously. OsNRT.1A has functionally diverged from previously reported NRT1.1 genes in plants and functions in upregulating the expression of N utilization-related genes not only for nitrate but also for ammonium, as well as flowering-related genes. Relative to the wild type, osnrt1.1a mutants exhibited reduced N utilization and late flowering. By contrast, overexpression of OsNRT1.1A in rice greatly improved N utilization and grain yield, and maturation time was also significantly shortened. These effects were further confirmed in different rice backgrounds and also in Arabidopsis thaliana Our study paves a path for the use of a single gene to dramatically increase yield and shorten maturation time for crops, outcomes that promise to substantially increase world food security.
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Proteínas de Transporte de Anión/metabolismo , Oryza/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Transporte de Anión/genética , Regulación de la Expresión Génica de las Plantas/genética , Regulación de la Expresión Génica de las Plantas/fisiología , Mutación/genética , Transportadores de Nitrato , Nitrógeno/metabolismo , Oryza/genética , Proteínas de Plantas/genéticaRESUMEN
Ammonia-oxidizing bacteria (AOB) and archaea (AOA) are two microbial groups mediating nitrification, yet little is presently known about their abundances and community structures at the transcriptional level in wastewater treatment systems (WWTSs). This is a significant issue, as the numerical abundance of AOA or AOB at the gene level may not necessarily represent their functional role in ammonia oxidation. Using amoA genes as molecular markers, this study investigated the transcriptional abundance and community structure of active AOA and AOB in 14 WWTSs. Quantitative PCR results indicated that the transcriptional abundances of AOB amoA (averaged: 1.6 × 108 copies g-1 dry sludge) were higher than those of AOA (averaged: 3.4 × 107 copies g-1 dry sludge) in all WWTSs despite several higher abundances of AOA amoA at the gene level. Moreover, phylogenetic analysis demonstrated that Nitrosomonas europaea and unknown clusters accounted for 37.66% and 49.96% of the total AOB amoA transcripts, respectively, suggesting their dominant role in driving ammonia oxidation. Meanwhile, AOA amoA transcripts were only successfully retrieved from 3 samples, and the Nitrosospaera sister cluster dominated, accounting for 83.46%. Finally, the substrate utilization kinetics of different AOA and AOB species might play a fundamental role in shaping their niche differentiation, community composition, and functional activity. This study provides a basis for evaluating the relative contributions of ammonia-oxidizing microorganisms (AOMs) to nitrogen conversions in WWTSs.
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Archaea , Purificación del Agua , Amoníaco , Archaea/genética , Nitrificación , Oxidación-Reducción , Filogenia , Microbiología del SueloRESUMEN
BACKGROUND: Recent studies have suggested that the gut microbiota is altered in children with juvenile idiopathic arthritis (JIA). However, age, sex, and body mass index (BMI) were not matched in the previous studies, and the results are inconsistent. We conducted an age-, sex-, and BMI-matched cross-sectional study to characterize the gut microbiota in children with JIA, and evaluate its potential in clinical prediction. METHODS: A total of 40 patients with JIA and 42 healthy controls, ranging from 1 to 16 years, were enrolled in this study. Fecal samples were collected for 16S rDNA sequencing. The data were analyzed using QIIME software and R packages. Specifically, the random forest model was used to identify biomarkers, and the receiver operating characteristic curve and the decision curve analysis were used to evaluate model performance. RESULTS: A total of 39 fecal samples from patients with JIA, and 42 fecal samples from healthy controls were sequenced successfully. The Chao 1 and Shannon-Wiener index in the JIA group were significantly lower than those in the control group, and the Bray-Curtis dissimilarity also differed significantly between the two groups. The relative abundance of 4 genera, Anaerostipes, Dialister, Lachnospira, and Roseburia, decreased significantly in the JIA group compared to those in the control group. The 4 genera included microbes that produce short-chain fatty acids (SCFAs) and were negatively correlated with some rheumatic indices. Moreover, 12 genera were identified as potential biomarkers by using the nested cross-validation function of the random forest. A random forest model constructed using these genera was able to differentiate the patients with JIA from the healthy controls, and the area under the receiver operating characteristic curve was 0.7975. The decision curve analysis indicated that the model had usefulness in clinical practice. CONCLUSIONS: The gut microbiota in patients with JIA is altered and characterized by a decreased abundance of 4 SCFA-producing genera. The decreases in the 4 genera correlated with more serious clinical indices. Twelve genera could be used as biomarkers and predictors in clinical practice. TRIAL REGISTRATION: The study is registered online at the Chinese Clinical Trial Registry on 11 May 2018 (registration number: ChiCTR1800016110).
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Artritis Juvenil/microbiología , Bacterias/clasificación , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN/métodos , Adolescente , Bacterias/genética , Estudios de Casos y Controles , Niño , Preescolar , Estudios Transversales , ADN Bacteriano/genética , ADN Ribosómico/genética , Heces/microbiología , Femenino , Microbioma Gastrointestinal , Humanos , Lactante , Masculino , FilogeniaRESUMEN
Metal-organic frameworks (MOFs)-supported noble metal nanoparticles (NMNPs) catalysts attract increasing attention due to their high durability and efficiency in catalytic reactions. In this work, Pt nanoparticles are inserted at the designated location inside MIL-100(Fe) to investigate the location-effect of NMNPs inside MOFs on the catalytic reaction. The comparison test on the reduction of p-nitrophenol suggests that the location of the Pt nanoparticles inside MIL-100(Fe) largely influences the catalytic performance and the Pt nanoparticles inside MIL-100(Fe) locate closer to the outer surface of the MIL-100(Fe), providing higher catalytic efficiency. Possible reasons are concluded as the location of the Pt nanoparticles inside MIL-100(Fe) dominates the reactants transport pathway and the loading amount of Pt nanoparticles.
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Single-layered, double-layered, and triple-layered Pt nanoparticles with a well-defined arrangement were encapsulated inside metal-organic frameworks (MOFs) to investigate the catalytic performance influenced by the progressive increasing of Pt nanoparticles inside MOFs; the results show that the catalytic activity of the Pt-MOF hybrid catalysts increases progressively with the progressive increasing of the Pt nanoparticles inside MOFs. Progressive increasing of Pt nanoparticles with a multiple-layered manner inside MOFs provides a new route for designing well-organized hybrid catalysts of noble metal nanoparticles and MOFs with enhanced catalytic activity.
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We report the first experimental observation of nonlinear standing waves excited by plasma-series-resonance-enhanced harmonics in low pressure, very high frequency, parallel plate, capacitively coupled plasmas. Spatial structures of the harmonics of the magnetic field, measured by a magnetic probe, are in very good agreement with simulations based on a nonlinear electromagnetics model. At relatively low pressure, the nonlinear sheath motion generates high-order harmonics that can be strongly enhanced near the series resonance frequencies. Satisfying certain conditions, such nonlinear harmonics induce radial standing waves, with voltage and current maxima on axis, resulting in center-high plasma density. Excitation of higher harmonics is suppressed at higher pressures.
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Food allergy is an abnormal immune response of the immune system to some foods, which has caused great harm to people's health. Therefore, it is particularly important to detect allergens in food. In this article, a hybridization chain reaction (HCR) was coupled with gold nanoparticles (AuNPs) to detect the allergen genes of peanut, soybean and sesame DNAs. Two hairpin probes (H1 and H2) were designed for the allergen target genes of peanut, soybean and sesame DNAs. In the presence of target DNA, the hybridization chain reaction was triggered by it producing long double-stranded DNA (dsDNA) products. In the gold nanoparticle system, long dsDNA couldn't be adsorbed on the surface of AuNPs. When the concentration of salt ions in the solution increased, gold nanoparticles accumulated and led to a decrease of ultraviolet absorption. In the absence of target DNA, no hybridization chain reaction occurred. The hairpin probes could be adsorbed on the surface of AuNPs and no accumulation happened for gold nanoparticles even if the concentration of salt ions in the solution was increased. This method required no enzymes and had a strong specificity, so it was very easy to distinguish target DNA from non-target DNA. The detection limit of three allergens detected by this method was as low as 0.5 nM. The feasibility of this method for the detection of commercial commodities had been demonstrated by the successful detection of the DNAs extracted from commercial commodities, which were treated with extreme thermostable single-stranded binding protein (ET SSB).
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Alérgenos/genética , ADN/análisis , Oro/química , Nanopartículas del Metal/química , Adsorción , Arachis/genética , Secuencia de Bases , Colorimetría/métodos , ADN/genética , Sondas de ADN/química , Sondas de ADN/genética , Secuencias Invertidas Repetidas , Límite de Detección , Técnicas de Amplificación de Ácido Nucleico/métodos , Hibridación de Ácido Nucleico , Sesamum/genética , Glycine max/genéticaRESUMEN
Metal-organic framework (MOF)-based magnetic Pt catalyst Fe3O4@Pt@MIL-100(Fe) core-shell heterostructures were prepared through transforming Fe3O4 into MIL-100(Fe) in benzene-1,3,5-tricarboxylic acid solution along with encapsulating the Pt nanoparticles successively adsorbed onto the surface of the Fe3O4 nanosphere and the continuously forming surfaces of the growing MIL-100(Fe) crystals. This method circumvented the obstacles, controlling the formation of metal nanoparticles (MNPs) inside MOFs or regulating growth of MOFs around the MNPs, for preparing an MNP-MOF composite catalyst. The obtained well-defined Fe3O4@Pt@MIL-100(Fe) core-shell heterostructure was shown promoting catalytic activity on the reduction of 4-nitrophenol due to the synergistic effect between the Pt nanoparticles and the MIL-100(Fe) shell and recycling convenience due to the rapid separation of the Fe3O4 core under an external magnetic field.