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1.
Anal Bioanal Chem ; 413(3): 813-820, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32783127

RESUMEN

In this work, a hybrid of multiwalled carbon nanotubes, nanogold, and reduced graphene (rGO/AuNPs/MWCNTs) was synthesized rapidly with an easy method, and then combined with chitosan (CS), which was fixed on a glassy carbon electrode (GCE) to construct a new kind of electrochemical sensor to simultaneously determine 4-aminophenol (4-AP) and acetaminophen (AC). When detecting 4-AP and AC simultaneously, the linear range is 0.12~12 µM for acetaminophen and 0.05~25 µM for 4-aminophenol; the detection limit is 42 nM for acetaminophen and 2.95 nM for 4-aminophenol. Compared with previously related reports, the proposed sensor has an excellent electrocatalytic performance for the redox of 4-AP and AC, which can effectively determine 4-AP and AC simultaneously in actual samples and has potential application prospect. Graphical abstract.


Asunto(s)
Acetaminofén/análisis , Aminofenoles/análisis , Técnicas Electroquímicas/instrumentación , Oro/química , Grafito/química , Nanopartículas del Metal/química , Nanotubos de Carbono/química , Electrodos , Límite de Detección , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión , Oxidación-Reducción , Difracción de Polvo , Reproducibilidad de los Resultados , Espectroscopía Infrarroja por Transformada de Fourier
2.
Bioorg Chem ; 95: 103507, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31884136

RESUMEN

Three pyrrol-2-aldehyde derivatives, including one new compound, jiangrine G (JG), two known compounds, jiangrine A (JA), and pyrrolezanthine (PZ), were isolated from the fermentation broth of Jiangella alba associated with a traditional Chinese medicinal plant Maytenus austroyunnanensis. The structure of jiangrine G was elucidated by a detailed spectroscopic data analysis including data from CD spectra. The anti-inflammatory activities assay demonstrated that JG and JA suppressed the production of pro-inflammatory cytokines including NO, IL-1ß, and IL-6 as well as inhibited the expression of iNOS in LPS-induced RAW 264.7 cells in a dose-dependent manner. While high concentration of PZ dramatically suppressed the protein expression of TNF-α, but stimulated the release of IL-1ß and IL-6. Western blot results revealed that JG, JA, and PZ modulated the expression of pro-inflammatory cytokines via MAPK p38 and NF-κB signaling pathways. For the unique structure of PZ, difference from JG and JA, the signaling pathway involved in mediating its effects on regulating the synthesis of IL-1ß and IL-6 are probably more complicated than that of JG and JA.


Asunto(s)
Actinobacteria/química , Antiinflamatorios no Esteroideos/farmacología , Inhibidores Enzimáticos/farmacología , FN-kappa B/antagonistas & inhibidores , Pirroles/farmacología , Proteínas Quinasas p38 Activadas por Mitógenos/antagonistas & inhibidores , Animales , Antiinflamatorios no Esteroideos/química , Antiinflamatorios no Esteroideos/aislamiento & purificación , Supervivencia Celular/efectos de los fármacos , Citocinas/antagonistas & inhibidores , Citocinas/metabolismo , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/aislamiento & purificación , Lipopolisacáridos/antagonistas & inhibidores , Lipopolisacáridos/farmacología , Ratones , Estructura Molecular , FN-kappa B/metabolismo , Óxido Nítrico Sintasa de Tipo II/antagonistas & inhibidores , Óxido Nítrico Sintasa de Tipo II/metabolismo , Pirroles/química , Pirroles/aislamiento & purificación , Células RAW 264.7 , Relación Estructura-Actividad , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo
3.
J Chem Phys ; 139(12): 124903, 2013 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-24089800

RESUMEN

We have investigated experimentally the structure formation processes during phase separation via spinodal decomposition above and below the spinodal line in a binary polymer blend system exposed to in-plane stationary thermal gradients using phase contrast optical microscopy and temperature gradient hot stage. Below the spinodal line there is a coupling of concentration fluctuations and thermal gradient imposed by the temperature gradient hot stage. Also under the thermal gradient annealing phase-separated domains grow faster compared with the system under homogeneous temperature annealing on a zero-gradient or a conventional hot stage. We suggest that the in-plane thermal gradient accelerates phase separation through the enhancement in concentration fluctuations in the early and intermediate stages of spinodal decomposition. In a thermal gradient field, the strength of concentration fluctuation close to the critical point (above the spinodal line) is strong enough to induce phase separation even in one-phase regime of the phase diagram. In the presence of a temperature gradient the equilibrium phase diagrams are no longer valid, and the systems with an upper critical solution temperature can be quenched into phase separation by applying the stationary temperature gradient. The in-plane temperature gradient drives enhanced concentration fluctuations in a binary polymer blend system above and below the spinodal line.

4.
Nat Biotechnol ; 41(1): 120-127, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36229611

RESUMEN

The genomic basis underlying the selection for environmental adaptation and yield-related traits in maize remains poorly understood. Here we carried out genome-wide profiling of the small RNA (sRNA) transcriptome (sRNAome) and transcriptome landscapes of a global maize diversity panel under dry and wet conditions and uncover dozens of environment-specific regulatory hotspots. Transgenic and molecular studies of Drought-Related Environment-specific Super eQTL Hotspot on chromosome 8 (DRESH8) and ZmMYBR38, a target of DRESH8-derived small interfering RNAs, revealed a transposable element-mediated inverted repeats (TE-IR)-derived sRNA- and gene-regulatory network that balances plant drought tolerance with yield-related traits. A genome-wide scan revealed that TE-IRs associate with drought response and yield-related traits that were positively selected and expanded during maize domestication. These results indicate that TE-IR-mediated posttranscriptional regulation is a key molecular mechanism underlying the tradeoff between crop environmental adaptation and yield-related traits, providing potential genomic targets for the breeding of crops with greater stress tolerance but uncompromised yield.


Asunto(s)
Resistencia a la Sequía , ARN Pequeño no Traducido , Zea mays/genética , Fitomejoramiento/métodos , Fenotipo , Sequías , Elementos Transponibles de ADN/genética , Estrés Fisiológico/genética
5.
RSC Adv ; 9(54): 31440-31446, 2019 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-35527947

RESUMEN

In this paper, Ag-Pd bimetallic nanoparticles uniformly distributed on reduced graphene oxide (rGO) were synthesized by redox reaction between Pd2+, Ag+and GO, and were characterized by X-ray diffractometry, field emission scanning electron microscopy, electrochemical impedance spectroscopy and thermal gravimetric analyses. A novel electrochemical sensor was constructed based on these nanocomposites using glassy carbon as a substrate. Under optimal conditions, the linear ranges were 0.50-300.00 µM for PA and 1.00-300.00 µM for 4-AP, with the detection limits of 0.23 µM for PA and 0.013 µM for 4-AP, respectively. This sensor was successfully applied to the determination of PA in pharmaceutical formulations and gave satisfactory results with a lower detection limit, wider linear range and good reproducibility.

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