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Basse Haaning posted an update 1 day, 19 hours ago
Projected population increases over the next 30 years have elevated the need to develop novel agricultural technologies to dramatically increase crop yield, particularly under conditions of high pathogen pressure. In this study, silica nanoparticles (NPs) with tunable dissolution rates were synthesized and applied to watermelon (Citrullus lanatus) to enhance plant growth while mitigating development of the Fusarium wilt disease caused by Fusarium oxysporum f. sp. niveum. The hydrolysis rates of the silica particles were controlled by the degree of condensation or the catalytic activity of aminosilane. The results demonstrate that the plants treated with fast dissolving NPs maintained or increased biomass whereas the particle-free plants had a 34% decrease in biomass. Further, higher silicon concentrations were measured in root parts when the plants were treated with fast dissolving NPs, indicating effective silicic acid delivery. In a follow-up field study over 2.5 months, the fast dissolving NP treatment enhanced fruit yield by 81.5% in comparison to untreated plants. These findings indicate that the colloidal behavior of designed nanoparticles can be critical to nanoparticle-plant interactions, leading to disease suppression and plant health as part of a novel strategy for nanoenabled agriculture.An enantioselective Pd(II)-catalyzed amino-cyclization and desymmetrizing nitrile addition cascade reaction of alkyne-tethered malononitriles is reported. This reaction forms two rings and one quaternary carbon center in a single step and serves as an efficient strategy for the construction of α-quaternary carbazolones with high enantioselectivities (up to 982 er). The utility of this method is demonstrated by product derivatization into a diverse array of heterocycles and a nitrile-containing leucomidine A analog.The manipulation of individual intrinsic point defects is crucial for boosting the thermoelectric performances of n-Bi2Te3-based thermoelectric films, but was not achieved in previous studies. In this work, we realize the independent manipulation of Te vacancies VTe and antisite defects of TeBi and BiTe in molecular beam epitaxially grown n-Bi2Te3 films, which is directly monitored by a scanning tunneling microscope. By virtue of introducing dominant TeBi antisites, the n-Bi2Te3 film can achieve the state-of-the-art thermoelectric power factor of 5.05 mW m-1 K-2, significantly superior to films containing VTe and BiTe as dominant defects. Angle-resolved photoemission spectroscopy and systematic transport studies have revealed two detrimental effects regarding VTe and BiTe, which have not been discovered before (1) The presence of BiTe antisites leads to a reduction of the carrier effective mass in the conduction band; and (2) the intrinsic transformation of VTe to BiTe during the film growth results in a built-in electric field along the film thickness direction and thus is not beneficial for the carrier mobility. This research is instructive for further engineering defects and optimizing electronic transport properties of n-Bi2Te3 and other technologically important thermoelectric materials.As a leftover of grease processing, the efficient utilization of erucic acid is still a challenge. An alternative strategy is to develop erucic acid-derived surfactants. However, erucic acid-based ionic liquid surfactants were barely involved. Here, a novel ionic liquid surfactant, benzyltrimethylammonium erucate (ErBTA), was developed by a simple neutralization reaction, and its aggregations in the diluted and concentrated solution were systematically studied by surface tension, conductivity, rheology, and cryo-TEM techniques. The results showed that ErBTA has a very low metaling point (-7.03 °C) and possesses excellent water solubility (Krafft temperature less then 4 °C). ErBTA alone starts to form micelles at a very low concentration (0.028 mmol/L) and then to form worm-based viscoelastic fluid at 4.07 mmol/L without any additives, exhibiting excellent self-assembly ability and thickening ability. This viscoelastic fluid formed by ErBTA can simultaneously respond to three stimuli common acid/alkaline, CO2 gas, and light, accompanied by an interesting gel-sol conversion, reflecting microstructure transition from wormlike micelles to spherical micelles. Although in essence CO2 and light also act as pH regulators in the current system, they provide more sophisticated approaches to tune pH. Such a viscoelastic fluid with the characteristics of easy availability, renewability of raw materials, the simplicity of fabrication, good water-solubility, and excellent thickening ability may be an attractive candidate for clean fracturing in oil/gas recovery and fluid drag reduction.The alkaline phosphatase (ALP) activity assay is very significant for disease diagnosis and biomedical research. PEG300 research buy Lanthanide metal-organic framework (Ln-MOF) based fluorescence sensors have great application potential in ALP activity assays. However, it is critical but challenging to investigate the emission law of Ln-MOFs for revealing rational design principles and selecting an appropriate MOF. Here, we describe a reasonable design strategy for dual-emission Ln-MOFs based on theoretical calculations. This strategy combines Reinhoudt empirical rule, intramolecular charge transfer theory, and aggregation/coordination-induced emission theory; reveals the luminescence law of Ln-MOFs; and provides theoretical guidance for the rational design of dual-emission Ln-MOFs. On the basis of this strategy, we create a dual-emission Tb-MOF fluorescent probe used for ALP activity assay and investigate the detection mechanism. The probe shows ultrasensitive (limit of detection 0.002 mU mL-1) and selective response to ALP, and it suits for point-of-care visual detection coupled with a self-designed portable enzyme activity assay kit and smartphone-assisted visual device. The kit-based visual assay method can accurately quantify the activity of ALP in real serum samples (recovery >93%, and relative error is less than 6.8% compared with the results of fluorescence spectrometer-based method) and consumes only 25 μL of serum. In addition, a logical decoder based on the “dual-key unlocking strategy” is designed, providing a feasible solution for the development of intelligent ALP activity detection equipment. As far as we know, this is the first report of a theoretical calculation-guided versatile design strategy for dual-emission Ln-MOFs and a portable enzyme activity assay kit for visual detection.