Photocontrolled pesticide delivery systems have broad
prospects
for application in agriculture. Here, a novel photoresponsive herbicide
delivery system was fabricated by functionalizing silica microsphere
surfaces with cinnamamide and encapsulating the silica-cinnamamide
with γ-cyclodextrin (γ-CD) to form a double-layered microsphere
shell loaded with pendimethalin (pendimethalin@silica-cinnamamide/γ-CD).
The microspheres showed remarkable loading capacity for pendimethalin
(approximately 30.25% w/w) and displayed excellent photoresponsiveness
and controlled release. The cumulative drug release rate exceeded
80% over 72 h under UV or sunlight irradiation. The herbicidal activity
of the microspheres against Echinochloa crusgalli (L.) Beauv. was almost the same as that of pendimethalin under UV
or sunlight. A bioactivity survey confirmed that the pendimethalin@silica-cinnamamide/γ-CD
microspheres exhibited longer duration weed control than commercial
pendimethalin. Allium cepa chromosomal
aberration assays demonstrated that the microspheres showed lower
genotoxicity than pendimethalin. These advantages indicate that pendimethalin@silica-cinnamamide/γ-CD
microspheres constitute an environmentally friendly herbicidal formulation.
Drying tea flowers into a high quality product is important to its commodity value. In the present work, a combination of microwave assisted drying and air drying (MAD-AD) were applied in fresh tea flowers processing and its effect on flavor quality, active nutraceutical compounds, and antioxidant capacities were studied. The results showed that compared to air drying (AD) and freeze drying (FD) tea flowers, the MAD-AD tea flowers had higher contents of active compounds such as catechins, flavonol glycosides, and triterpenoid saponins, and possessed high antioxidant activities. Moreover, this drying method improved tea flowers’ color appearance and preserved more flowery fragrance. This combined method could be of interest as an industrial method in tea flowers drying with the benefit of reduced processing time, more reserved active compounds and high quality of products.
Metamaterials have demonstrated great potential for controlling wave propagation since they are flexibly adjustable. A new one-dimensional metamaterial model with both a negative effective moment of inertia and negative effective stiffness is proposed. A negative effective moment of inertia and negative effective stiffness can be achieved by adjusting the structural parameters in certain frequency ranges. Bandgaps in the low-frequency range with exponential wave attenuation can be generated in the metamaterial. A flat band is obtained that couples two Bragg bandgaps to achieve a wide bandgap in the low-frequency range, where the effective moment of inertia and effective stiffness are both infinite. A zero-frequency bandgap can be achieved by adjusting the structural parameters. Quick attenuation of wave is observed in the zero-frequency ranges with single-negative parameters. Furthermore, an ultrawide-zero-frequency bandgap is obtained by optimizing the structural parameters of the system. In addition, it is easy to switch between the Bragg and locally resonant bandgaps. This new metamaterial can be applied to ultralow-frequency-vibration isolation.
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