RÉSUMÉ
Utilizing softly confined self-assembly at the water surface represents a promising approach for the fabrication of two-dimensional molecular monolayers (2D MMs), which have predominantly been concentrated on amphiphilic organic compounds before. Herein, we introduce a straightforward method termed "water surface-assisted molecular deposition (WSAMD)" to organize nonamphiphilic molecules into dense monolayers with high reproducibility. To underscore the versatility and merit of this methodology in the field of supramolecular electronics, we have successfully fabricated a range of defect-free, uniform semiconducting polymer monolayers, featuring a thickness reflective of molecular architectures. The charge carrier mobility could reach 0.05 cm2 V-1 s-1 for holes and 3.5 × 10-4 cm2 V-1 s-1 for electrons, respectively, in p-type and n-type polymeric monolayers when tested as the active layer in field-effect transistors. Furthermore, in situ polymerization reactions can be exploited to generate conductive monolayers of macromolecules such as polybenzylaniline (PBnANI) and polypyrrole (PPy), where PBnANI monolayers exhibit channel length-dependent conductivity, up to 0.37 S cm-1. The advent of the WSAMD method heralds a significant leap forward in the advancement of molecular 2D materials, catalyzing new avenues of exploration within material chemistry.
RÉSUMÉ
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.
Sujet(s)
Résistance à la sécheresse , Petit ARN non traduit , Zea mays/génétique , Amélioration des plantes/méthodes , Phénotype , Sécheresses , Éléments transposables d'ADN/génétique , Stress physiologique/génétiqueRÉSUMÉ
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.
Sujet(s)
Acétaminophène/analyse , Aminophénols/analyse , Techniques électrochimiques/instrumentation , Or/composition chimique , Graphite/composition chimique , Nanoparticules métalliques/composition chimique , Nanotubes de carbone/composition chimique , Électrodes , Limite de détection , Microscopie électronique à balayage , Microscopie électronique à transmission , Oxydoréduction , Diffraction sur poudre , Reproductibilité des résultats , Spectroscopie infrarouge à transformée de FourierRÉSUMÉ
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.
Sujet(s)
Actinobacteria/composition chimique , Anti-inflammatoires non stéroïdiens/pharmacologie , Antienzymes/pharmacologie , Facteur de transcription NF-kappa B/antagonistes et inhibiteurs , Pyrroles/pharmacologie , p38 Mitogen-Activated Protein Kinases/antagonistes et inhibiteurs , Animaux , Anti-inflammatoires non stéroïdiens/composition chimique , Anti-inflammatoires non stéroïdiens/isolement et purification , Survie cellulaire/effets des médicaments et des substances chimiques , Cytokines/antagonistes et inhibiteurs , Cytokines/métabolisme , Relation dose-effet des médicaments , Antienzymes/composition chimique , Antienzymes/isolement et purification , Lipopolysaccharides/antagonistes et inhibiteurs , Lipopolysaccharides/pharmacologie , Souris , Structure moléculaire , Facteur de transcription NF-kappa B/métabolisme , Nitric oxide synthase type II/antagonistes et inhibiteurs , Nitric oxide synthase type II/métabolisme , Pyrroles/composition chimique , Pyrroles/isolement et purification , Cellules RAW 264.7 , Relation structure-activité , p38 Mitogen-Activated Protein Kinases/métabolismeRÉSUMÉ
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.
RÉSUMÉ
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.