Prolonged Repellent Activity of Plant Essential Oils against Dengue Vector, Aedes aegypti

Repellents are effective personal protective means against outdoor biting mosquitoes. Repellent formulations composed of EOs are finding increased popularity among consumers. In this study, after an initial screening of 11 essential oils (EOs) at the concentration of 33 μg/cm², five of the most repellent EOs, Perovskia atriplicifolia, Citrus reticulata (fruit peels), C. reticulata (leaves), Mentha longifolia, and Dysphania ambrosioides were further investigated for repellent activity against Aedes aegypti mosquitoes in time span bioassays. When tested at the concentrations of 33 μg/cm², 165 μg/cm² and 330 μg/cm², the EO of P. atriplicifolia showed the longest repellent effect up to 75, 90 and 135 min, respectively, which was followed by C. reticulata (peels) for 60, 90 and 120 min, M. longifolia for 45, 60 and 90 min, and C. reticulata (leaves) for 30, 45 and 75 min. Notably, the EO of P. atriplicifolia tested at the dose of 330 μg/cm² showed complete protection for 60 min which was similar to the commercial mosquito repellent DEET. Gas chromatographic-mass spectrometric analyses of the EOs revealed camphor (19.7%), limonene (92.7%), sabinene (24.9%), carvone (82.6%), and trans-ascaridole (38.8%) as the major constituents of P. atriplicifolia, C. reticulata (peels), C. reticulata (leaves), M. longifolia, and D. ambrosioides, respectively. The results of the present study could help develop plant-based commercial repellents to protect humans from dengue mosquitoes.

Chemical Composition, Larvicidal and Repellent Activities of Wild Plant Essential Oils against Aedes aegypti

Bio-degradable and eco-friendly essential oils (EOs) extracted from Mentha longifolia, Salsola imbricata, Erigeron bonariensis, E. canadensis, Ailanthus altissima, and Zanthoxylum armatum were investigated for their repellent and larvicidal potential against Aedes aegypti mosquitoes. The EOs of M. longifolia, S. imbricata, E. bonariensis, E. canadensis, A. altissima, and Z. armatum exhibited 99.0%, 96.8%, 40.2%, 41.7%, 29.1%, and 13.2% repellency against mosquitoes at a tested dose of 33.3 μg/cm², respectively. In time span bioassays, the EOs of M. longifolia, S. imbricata, E. bonariensis, and E. canadensis showed more than 40% repellency for 60 min at a tested dose of 330 μg/cm². Larvicidal bioassays revealed that larvae of Ae. aegypti were the most susceptible to M. longifolia (LC₅₀, 39.3 mg/L), E. bonariensis (LC₅₀, 26.0 mg/L), E. canadensis (LC₅₀, 35.7 mg/L), and Z. armatum (LC₅₀, 35.9 mg/L) EOs upon 48 h exposure. The most abundant constituents in the EOs of M. longifolia, S. imbricata, E. bonariensis, E. canadensis and A. altissima were piperitone oxide (45.5%), carvone (39.9%), matricaria ester (43.1%), (31.7%) and eugenol (24.4%), respectively. Our study demonstrates that EOs of M. longifolia, S. imbricata, E. bonariensis, and E. canadensis might be used to control Ae. aegypti mosquitoes without harming humans or the environment.

Do entrepreneurial orientation and intellectual capital influence SMEs' growth? Evidence from Pakistan

This research analyzes the impacts of intellectual capital (IC) and the balancing power of entrepreneurial orientation (EO) on innovation growth (IG) in Pakistan's SME sector. A quantitative approach on smart PLS has been applied through the SEM model, backed by a survey to gather primary data from 256 participants of Pakistan's SME sector. A significant effect of human capital on Pakistani firms' IG was identified. In contrast, the effect of structural capital was determined to be insignificant over the IG of Pakistani firms. On the other hand, the customer capital's effect was also significant over Pakistani firms' innovation growth. Little moderation of EO between human capital and IG has been determined. The moderations of "EO between human capital and innovation growth" and "EO between structural capital and innovation growth" were insignificant. However, the moderation of EO between customer capital and IG was significant. The scope of this study is limited to firms in Pakistan and can be extended to firms in other regions, which can provide broad findings.

Nexus between energy policy and environmental performance in China: The moderating role of green finance adopted firms

This study measures the association between resources and the atmosphere; social and environmental aspects of energy production have become critical. In this context, the aim of this research is to explore the mediating effect of renewable energy patents in developing potential frameworks for energy policy viewpoints on the climate. The study took panel data from 2010 to 2017 and used a non-radial data envelopment analysis (DEA) process and panel data model for 30 Chinese provinces. The findings indicate that between 2010 and 2017, the average environmental efficiency index (EPI) of Chinese areas increased by 9.88%. When firms' internal variables are proxied by their commodity (revenue), the relationship term's point approximate coefficient is about 0.05. This magnitude means that a 1% rise in a company's assets will result in a 5% increase is estimated to be about 0.157, implying that a 1% rise in firm leverage is correlated with a 15.7%. Finally, based on the study results, some policy implications were proposed.