The aim of this work is to develop a new generation of repellent products with a long-lasting protection based on a natural component, para-menthane-3,8-diol (PMD). The active is first rendered soluble in a surfactantless microemulsion (H(2)O/(i)PrOH/PMD) and then in classical microemulsions. The presence of self-associated nanostructures is detected by dynamic light scattering (DLS). A synergetic system of surfactants (Cremophor) RH40 and Texapon N70) is used. Additionally, 2-ethylhexane-1,3-diol and ethyl (-)-(S)-lactate are incorporated. The final product contains, as main components, 46% of H(2)O, 25% of (i)PrOH, 20% of non-H(2)O-soluble PMD, and only 4% of surfactants. Investigations of lasting protection on human volunteers are carried out using a cage test bioassay protocol and Aedes aegypti mosquitoes. A complete protection of 315 min is found on the test persons using the surfactantless microemulsion. An extension is observed with the final formulation to reach a mean of complete protection of 385 min. This study demonstrates that alternative formulations using a natural active instead of synthetic chemicals like N,N-diethyl-m-methylbenzamide (DEET) can be efficient for human protection against mosquitoes.
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http://dx.doi.org/10.1002/cbdv.200800225 | DOI Listing |
Adv Sci (Weinh)
January 2024
Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, China.
In addressing the demand for hierarchically mesoporous metal-organic frameworks (HMMOFs) with adjustable large mesopores, a method based on the synergistic effects of low-temperature microemulsions and Hofmeister ions is developed. Low temperature dramatically enhanced the solubility of hydrophobic solvent in the microemulsion core, enlarging the mesopores in HMMOFs replica. Meanwhile, Hofmeister salt-in ions continuously controlled mesopore expansion by modulating the permeability of swelling agent into the microemulsion core.
View Article and Find Full Text PDFPhys Rev Lett
October 2023
Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA.
We report the first numerical prediction of a "spin microemulsion"-a phase with undulating spin domains resembling classical bicontinuous oil-water-surfactant emulsions-in two-dimensional systems of spinor Bose-Einstein condensates with isotropic Rashba spin-orbit coupling. Using field-theoretic numerical simulations, we investigated the melting of a low-temperature stripe phase with supersolid character and find that the stripes lose their superfluidity at elevated temperature and undergo a Kosterlitz-Thouless-like transition into a spin microemulsion. Momentum distribution calculations highlight a thermally broadened occupation of the Rashba circle of low-energy states with macroscopic and isotropic occupation around the ring.
View Article and Find Full Text PDFLangmuir
August 2023
CSGI, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy.
Cultural heritage is a crucial resource to increase our society's resilience. However, degradation processes, enhanced by environmental and anthropic risks, inevitably affect works of art, hindering their accessibility and socioeconomic value. In response, interfacial and colloidal chemistry has proposed valuable solutions over the past decades, overcoming the limitations of traditional restoration materials and granting cost- and time-effective remedial conservation of the endangered artifacts.
View Article and Find Full Text PDFHeliyon
June 2023
College of Pharmacy, Jiamusi University, Jiamusi, 154007, China.
Cinnamon oil (CO) is a classic Chinese medicine with excellent soothing effects on exhaustion, weakness and depression. Cinnamaldehyde is the main active ingredient of cinnamic oil. Although CO have antidepression-like effects, limited information is available.
View Article and Find Full Text PDFZhongguo Zhong Yao Za Zhi
March 2023
Jiangsu Key Laboratory for High Technology Research of Traditional Chinese Medicine Formulae, National-Local Joint Engineering Research Center of Resources Industrialization of Chinese Meteria Medica and Prescription-oriented Innovative Drugs, Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, Nanjing University of Chinese Medicine Nanjing 210023, China.
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