The yellow fever mosquito Aedes aegypti has developed resistance to DDT in the Caribbean region and in South-East Asia, but not in West Africa. Therefore West African strains were compared with South-East Asian strains for their response to laboratory selection with DDT. It was found that West African strains were much slower to respond initially, but eventually could build up a high degree of DDT-resistance. By crossing and backcrossing with a susceptible marker-gene strain, it was found that this resistance was due to a single gene linked with the gene y (yellow) on chromosome 2 at a cross-over distance of approximately 35 units in an Upper Volta strain as in a Bangkok strain; interstrain crosses indicated that the gene was the same as that in a Trinidad strain and in one from Penang. Dieldrin-resistance could be readily induced in the Upper Volta strain and proved to be due to a gene also linked with y but at a crossover distance of approximately 25 units, comparable to that in Caribbean strains previously studied. Material from Karachi, West Pakistan, developed a dieldrin-resistance also showing 25% crossing over with y, and a DDT-resistance also linked with this chromosome-2 marker gene.
Monoglycerides (MGs) and phytosterols (PS) are known to form firm oleogels with liquid oil. However, the oleogels are prone to undergo polymorphic transition over time that lead to crystals' aggregation thus, compromises physical properties. Thus, we combined MGs with PS to control the crystallization and modify the morphology of the combination oleogels, as both components are reported to interact together. The oleogels were prepared at different ratio combinations and characterized in their rheological, thermal, morphology, and diffraction properties. The results showed that the 8:2 MGP:PS exhibited higher storage modulus (G') than the MGP mono-component. The combination oleogels exhibited effects on the crystallization and polymorphic transition. Consequently, the effects led to change in the morphology of the combination oleogels which was visualized using optical and electron microscope. The resultant effect on the morphology is associated with crystal defect. Due to observable crystals of MGP and PS, it is speculated that the combination oleogels formed a mixed crystal system. This was confirmed with diffraction analysis in which the corresponding peaks from MGP and PS were observed in the combination oleogels. However, the 8:2 oleogel exhibited additional peak at 35.41Å. Ultimately, the 8:2 was the optimum combination observed in our study. Interestingly, this combination is inspired by nature as sterols (phytosterols) are natural component of lipid membrane whilst MGP has properties similar to phospholipids. Hence, the results of our study not only beneficial for oil structuring, but also for the fields of biophysical and pharmaceutical.
Worker psychological health is a significant global imperative which requires national policy action and stakeholder engagement. While national policy is a critical lever for improving worker psychological health, some countries are more progressive than others in relation to policy development and/or implementation. At the Joint Congress of the International Commission on Occupational Health, Scientific Committee on Work Organization and Psychosocial Factors and the Asia Pacific Academy for Psychosocial Factors Work in Tokyo (September 2023), a Global Roundtable was designed to initiate international dialogue and knowledge exchange regarding relevant national policy approaches. The Global Roundtable involved experts from diverse regions alongside an engaged audience of congress attendees and facilitators. Qualitative data were analysed against the five components of the National Policy Index tool, comprising policy priority, specific laws, nation-wide initiatives, sector-oriented initiatives, national survey and/or studies. Analysis revealed that while work-related psychological health is a policy priority across many countries, at the same time, there are global gaps in both legislation specificity and active regulation across different countries. For future policy development across countries, it will be beneficial to continue and deepen international discourse and for countries to share their approaches with others.