scholarly journals Natural DEET substitutes that are strong olfactory repellents of mosquitoes and flies

2016 ◽  
Author(s):  
Sean Michael Boyle ◽  
Tom Guda ◽  
Christine Krause Pham ◽  
Sana Khalid Tharadra ◽  
Anupama Dahanukar ◽  
...  

SUMMARYDespite shortcomings, N,N-Diethyl-3-methylbenzamide (DEET) has remained the gold-standard of insect repellents for >60 years. There are significant impediments to finding improved substitutes because the molecular targets causing repellency are unclear, new chemistries will require significant human-safety testing, and predicted costs for development are exorbitant. Here we identify shared structural features important for repellency and using a supervised chemical-informatics method screen insilico >400,000 compounds to identify >100 natural compounds as candidate repellents. We select 4 candidates that are affordable, 3 approved as safe for human food use, and demonstrate that they are strong olfactory and gustatory repellents to both mosquitoes and Drosophila. The chemicals do not dissolve plastic and have a mild and pleasant odor. These repellents are representative of a new generation of affordable substitutes for DEET that can be rapidly deployed globally because of excellent human-safety profiles, and have great potential in reducing deadly diseases by reducing mosquito-human contact.

2019 ◽  
Author(s):  
Preston K. Manwill ◽  
Megha Kalsi ◽  
Sijin Wu ◽  
Xiaolin Cheng ◽  
Peter M. Piermarini ◽  
...  

AbstractThe Aedes aegypti mosquito serves as a major vector for viral diseases, such as dengue, chikungunya, and Zika, which are spreading across the globe and threatening public health. In addition to increased vector transmission, the prevalence of insecticide-resistant mosquitoes is also on the rise, thus solidifying the need for new, safe and effective insecticides to control mosquito populations. We recently discovered that cinnamodial, a unique drimane sesquiterpene dialdehyde of the Malagasy medicinal plant Cinnamosma fragrans, exhibited significant larval and adult toxicity to Ae. aegypti and was more efficacious than DEET – the gold standard for insect repellents – at repelling adult female Ae. aegypti from blood feeding. In this study several semisynthetic analogues of cinnamodial were prepared to probe the structure-activity relationship (SAR) for larvicidal, adulticidal and antifeedant activity against Ae. aegypti. Initial efforts were focused on modification of the dialdehyde functionality to produce more stable active analogues and to understand the importance of the 1,4-dialdehyde and the α,ß-unsaturated carbonyl in the observed bioactivity of cinnamodial against mosquitoes. This study represents the first investigation into the SAR of cinnamodial as an insecticide and repellent against the medically important Ae. aegypti mosquito.


2020 ◽  
pp. 152808372097016
Author(s):  
Laimutė Stygienė ◽  
Sandra Varnaitė-Žuravliova ◽  
Aušra Abraitienė ◽  
Audronė Sankauskaitė ◽  
Virginija Skurkytė-Papievienė ◽  
...  

The use of a new generation chemical fibers with various functional additives offers new possibilities for the development of advanced (multi)functional textile products. Such compounds as phase change materials (PCMs), metals (like cooper, silver), also natural or chemical insect repellents, FIR emitting ceramic particles and etc. incorporated into fibres’ structure are essential for development of knitted fabrics directly contacting to the skin with effective thermoregulation and such protective properties as: antimicrobial, antistatic, repellence against blood sucking insects. The main parts of socks investigated were knitted in plain plated single jersey pattern. The 3-ply twisted yarns of new structures were used in the outer layer of socks. Yarns were made by using single yarns with PCMs, insect repellent permethrin, ceramic and silver additives containing fibres (Cell Solution® Clima, Cell Solution® Protection, Resistex® Silver). The inner layer of socks was made of polyester (PES) 3-ply twisted yarns with different number of filaments resulted in different structures of socks’ fabric. Based on all obtained thermoregulating and protective characteristics of investigated different knitted fabric structures of socks, the optimal knitted socks were selected. The obtained results of investigations are significant for the development of other knitted fabrics worn next to the skin.


2020 ◽  
Vol 15 ◽  
pp. 155892502096735
Author(s):  
Li Niu ◽  
Xuhong Miao ◽  
Gaoming Jiang ◽  
Ailan Wan ◽  
Yutian Li ◽  
...  

Advanced triboelectric nanogenerator techniques provide a massive opportunity for the development of new generation wearable electronics, which toward multi-function and self-powering. Textiles have been refreshed with the requirement of flexible electronics in recent decades. In particular, knitted-textiles have exhibited enormous and prominent potential possibilities for smart wearable devices, which are based on the merits of high stretchability, excellent elasticity, comfortability as well as compatibility. Combined knitted textiles with nanogenerator techniques will promote the knitted textile triboelectric nanogenerators (KNGs) emerging, endowing conventional textiles with biomechanical energy harvesting and sensing energy supplied abilities. However, the design of KNGs and the construction of KNGs are based on features of human motions symbolizing considerable challenges in both high efficiency and excellent comfort. Currently, this review is concerned with KNGs construction account of triboelectric effects referring to knitted-textile classifications, structural features, human motion energy traits, working mechanisms, and practical applications. Moreover, the remaining challenges of industrial production and the future prospects of knitted-textile triboelectric nanogenerators of harvesting biomechanical energy are presented.


2013 ◽  
Vol 2013 ◽  
pp. 1-18 ◽  
Author(s):  
Neil Vargesson

Thalidomide remains one of the world’s most notorious drugs due to the severe birth defects it induced in children between 1957 and 1962. Yet, to some this drug is a lifesaver, as it now enjoys renaissance in the treatment for a wide range of conditions including leprosy, multiple myeloma, Behcet’s disease, and some cancers. However, thalidomide has also been linked to causing a new generation of thalidomide survivors in Brazil, where the drug is used to treat leprosy. Surprisingly how thalidomide causes birth defects and how it acts in the treatment of clinical conditions are still far from clear. In the past decade great strides in our understanding of the actions of the drug, as well as molecular targets, have been made. The purpose of this review is to look at the recent work carried out into understanding how thalidomide causes birth defects, it’s molecular targets and the challenges that remain to be elucidated. These challenges include identifying clinically relevant but nonteratogenic forms of the drug, and the mechanisms underlying phocomelia and species specificity.


Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Aleksei Mikhailov ◽  
Brian Hansen ◽  
Matthew Fazio ◽  
Stanislav Zakharkin ◽  
Jichao Zhao ◽  
...  

Introduction: Conventional multielectrode mapping is not sufficient to reveal subsurface intramural activation. Thus, atrial fibrillation (AF) driver identification remains challenging. To overcome these limitations we utilized machine learning (ML) to identify AF drivers based on the combination of electrogram (EGM) and 3D structural magnetic resonance imaging (MRI) features. Hypothesis: Detailed electrogram features analysis, including minor deflections, combined with local structural features, can be used to define AF driver. Methods: Sustained AF was mapped in coronary perfused explanted human atria (n=7) with near-infrared optical mapping (NIOM) (0.3-0.9mm 2 resolution) and 64-electrode mapping catheter (3mm 2 resolution). Unipolar EGMs were analyzed for multiple features of the steepest negative deflection and the 2nd-4th steepest deflections in multicomponent EGMs. Atria underwent 9.4T MRI (154-180μm 3 resolution) with gadolinium enhancement and histology validation of fibrosis. Both 3D structural and EGM data from NIOM defined driver and non-driver regions were processed by ML algorithms (LR; PLSDA; GBM; CRF; PSVM; RSVM) using double cross-validation. Results: AF drivers’ reentrant tracks were defined by NIOM activation mapping, the gold-standard, and confirmed by targeted ablation. The best performing ML algorithm (PLSDA) correctly classified mapped driver region with 76.1% accuracy on the testing data. The most important features included sub-endocardial fibrosis, sub-epicardial fiber orientation, local wall thickness, beat-to-beat variability of multicomponent EGM deflections. Conclusions: The ML models pre-trained on combined EGM and structural features allow efficient classification of AF driver vs non-driver regions defined by the NIOM gold-standard. The results suggest that AF driver substrates formed by the combination of 3D fibrotic structural features, which correlate with local EGM characteristics.


2013 ◽  
Vol 59 (3) ◽  
pp. 267-294 ◽  
Author(s):  
A.E. Fedosov ◽  
S.A. Moshkovskii ◽  
K.G. Kuznetsova ◽  
B.M. Olivera

A review describes general trends in research of conotoxins that are peptide toxins isolated from sea gastropods of the Conus genus, since the toxins were discovered in 1970 . There are disclosed a conotoxin classification, their structure diversity and different ways of action to their molecular targets, mainly, ion channels. In the applied aspect of conotoxin research, drug discovery and development is discussed, the drugs being based on conotoxin structure. A first exemplary drug is a ziconotide, which is an analgesic of new generation.


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