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This study investigated chemical compositions and biocidal activities from the aerial parts of Rhododendron thymifoliumagainst Tribolium castaneum, Lasioderma serricorne, and Ditylenchus destructor. In total, 13 components were isolated from the aerial parts of R. thymifoliumby chromatographic separation techniques. Based on the results of MS, 1H NMR, and 13C NMR spectrometry, their structures were determined as ent-kaurane-16β-ol (1), pentacosane (2), undecanoic acid, ethyl ester (3), 1-Tridecanethiol (4), 1-Dodecanol (5), 4-Methyl-7-hydroxycoumarin (6), tertradecan-1-ol (7), apocynin (8), 3-Methoxy-4-methylbenzaldehyde (9), scopoletin (10), hyperin (11), quercetin (12), acetophenone (13). In addition, ent-kaurane-16β-ol (1) was isolated from R. thymifoliumfor the first time. Then, the insecticidal toxicities against T. castaneum, L. serricorne, and D. destructor. of compounds 1–13 were evaluated, and the results showed that apocynin (8) and acetophenone (13) exhibited obvious contact activity against the storage pests with LD50values of 6.46 and 8.72 μg/adult respectively. Acetophenone (13) showed excellent contact activity against D. destructorwith LC50values of 0.08 mg/mL. The study clearly showed the active fractions from R. thymifoliumhave might potential to be developed into potential compounds on storage insect prevention.

Advances in single-atom (-site) catalysts (SACs) provide a new solution of atomic economy and accuracy for designing efficient electrocatalysts. In addition to a precise local coordination environment, controllable spatial active structure and tolerance under harsh operating conditions remain great challenges in the development of SACs. Here, we show a series of molecule-spaced SACs (msSACs) using different acid anhydrides to regulate the spatial density of discrete metal phthalocyanines with single Co sites, which significantly improve the effective active-site numbers and mass transfer, enabling one of the msSACs connected by pyromellitic dianhydride to exhibit an outstanding mass activity of (1.63 ± 0.01) × 105A·g–1and TOFbulkof 27.66 ± 1.59 s–1at 1.58 V (vsRHE) and long-term durability at an ultrahigh current density of 2.0 A·cm–2under industrial conditions for oxygen evolution reaction. This study demonstrates that the accessible spatial density of single atom sites can be another important parameter to enhance the overall performance of catalysts.

AbstractThis study investigated the biological activity of essential oils (EOs) and their main components (caryophyllene and cuminol) against Tribolium castaneumlarvae and Lasioderma serricorneadults. EOs were extracted from both flowers and leaves of Elsholtzia stauntoni. The results indicated that the EOs derived from both flowers and leaves, as well as their main components (caryophyllene and cuminol), exhibited contact activities with LD50values of 35.11, 43.66, 15.44, and 26.05 μg/larva, respectively, against T. castaneumlarvae. Moreover, they demonstrated obvious contact toxicities with LD50values of 14.15, 11.18, 17.81, and 13.91 μg/adult, respectively, against L. serricorneadults. Additionally, EOs from both flowers and leaves exhibited fumigant activities against T. castaneumlarvae (LC50= 24.42 and 62.54 mg/L) and L. serricorneadults (LC50= 15.26 and 24.29 mg/L). Furthermore, the EOs of flowers and leaves and their main components (caryophyllene and cuminol) remained significantly repellency to T. castaneumlarvae and L. serricorneadults within the testing concentration range of 78.63-15.83 nL/cm2after 12 h of exposure. These findings suggested that the EO from E. stauntoniand its two major components could potentially be developed as a natural insecticide for controlling T. castaneumlarvae and L. serricorneadults.