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Sensors play an essential role in gathering environmental information for greenhouse farming. Wireless sensor network creates and manages links between sensor blocks in the system. As a result, not only various environmental parameters can be collected, but the sensor location can also be flexibly deployed. Sensor blocks require low energy consumption and inexpensive implementation costs with typical operating conditions. The research has built a wireless sensor network based on open Radio Frequency (RF) technology. Each sensor block has a low deployment cost and operates independently via a solar-powered unit. A novel communication protocol is designed for the proposed sensor network. In addition, a greenhouse controller exploiting designed wireless sensor networks is also constructed to evaluate the practicality of the system. Sensor networks developed are intended to be applied to the existing agricultural greenhouses in the surveyed area. The greenhouse is medium-sized, and the system implemented in practice is for vegetable farming. As a result, the controller can connect to the Internet to serve IoT links and applications. Experimental results prove the practicality of sensor blocks and the stability and efficiency of the wireless sensor network. It helps to reduce deployment costs and improve applicability. In addition, the sensor blocks are designed and built with low energy consumption, which can be operated with a small solar power source.

The present study aims to describe the chemical composition of essential oils from three Vietnamese Annonaceae species, Meiogyne virgata, M. vietnamica, and Orophea polycarpa, and their antimicrobial activity. Essential oils were extracted by hydro-distillation. From the GC-FID/MS (gas chromatography-flame ionization detection and mass spectrometry) analysis, the leaf essential oil of M. virgata was reported to contain the major compound germacrene D (42.48%). Spathulenol (24.51%), bicyclogermacrene (18.58%), β-selinene (11.14%), and germacrene D (8.20%) can be seen as the main compound in M. vietnamica leaf essential oil. α-Phellandrene (39.35%), bicyclogermacrene (13.07%), β-phellandrene (10.87%), and limonene (8.27%) represented O. polycarpa leaf essential oil. Essential oil of M. virgata leaves exhibited strong antimicrobial activity against the Gram (+) bacterium Bacillus subtilis ATCC 5230, the Gram (-) bacterium Escherichia coli ATCC 8739, and the fungus Aspergillus niger ATCC 9587 with the same MIC value of 16 μg/mL. The docking method showed that germacrene D has the ΔGbinding (binding affinity) values of –6.68, –5.265, and –5.602 kcal/mol with the proteins E. coli DNA gyrase, B. subtilis TasA, and A. niger PhyA, respectively. Alkyl and pi-alkyl interactions are the main contributors to the binding affinity between the studied proteins and ligands. Furthermore, germacrene D is predicted to have low toxicity and is not active against any of the considered organ targets. [ABSTRACT FROM AUTHOR]