Identifying the interfaces between perceived multi-hazards and socio-ecological risks to strengthen local adaptations.

Multi-hazards are a great concern in the present world. Likewise, the coastal part of Bangladesh is highly vulnerable to multi-hazards, including waterlogging, surface water salinity, land use change, prolonged dry seasons, and groundwater salinity. Multi-hazards and associated risks make local adaptations more difficult over time. Thus, the purpose of this study is to explore the connection between multi-hazards and their associated socio-ecological risks in the southwestern coastal part of Bangladesh. Mixed-methods approaches were used to collect all the data, and statistical analyses were performed to analyze the data. Results revealed that waterlogging significantly influenced local food access, poverty, child marriage, and divorce problems. Surface water salinity and land use change showed significant differences with the widening of salinity-affected areas. Waterlogging, land use change, and a prolonged dry season all showed significant differences in freshwater access. Prolonged dry seasons and groundwater salinity both have a significant impact on human health. Waterlogging and groundwater salinity significantly influence human migrations. These findings may strengthen local adaptation policies for salinity hazards, land use planning, household poverty, food access, livelihoods, water access, health effects, child marriage, and human migration. In addition, our findings indicate the potential to address the existing knowledge gaps pertaining to coastal hazards, risks, and adaptation issues.

Chain transfer agents for the catalytic ring opening metathesis polymerization of norbornenes.

Here, we present a detailed study of the metathesis activity of conjugated 1,3 diene derivatives in ring opening metathesis polymerization (ROMP) using Grubbs' 3rd generation catalyst (G3). A comprehensive screening of those derivatives revealed that monosubstituted 1,3 dienes show similar reactivities towards G3-alkylidenes as norbornene derivatives. Therefore, they represent perfect candidates for chain transfer agents in a kinetically controlled catalytic ROMP. This unprecedented reactivity allowed us to catalytically synthesize mono-end-functional poly(norborneneimide)s on the gram scale. Much more complex architectures such as star-shaped polymers could also be synthesized catalytically for the very first time via ROMP. This inexpensive and greener route to produce telechelic ROMP polymers was further utilized to synthesize ROMP block copolymers using bifunctional ROMP and ATRP/NCL initiators. Finally, the regioselective reaction of G3 with 1,3 diene derivatives was also exploited in the synthesis of a ROMP-PEG diblock copolymer initiated from a PEG macroinitiator.

Groundwater quality and human health risk assessment in selected coastal and floodplain areas of Bangladesh.

Groundwater aquifers are a common source of drinking water in Bangladesh. However, groundwater contamination is a major public health concern across the country. This research aims to examine the groundwater quality and health concerns using a random sampling process. Multivariate statistical and health risk analyses of elements were performed to determine the source of contaminants and their effects on human health. A total of 24 parameters were analyzed, where Na+, NH4+, K+, Mg2+, F-, NO3-, Mn, Fe, Se, U, and As concentrations were found to be high in different sampling points compared to the Department of Environment of Bangladesh (DoE), and the World Health Organization (WHO) groundwater quality standards. Principal Component Analysis (PCA) and Cluster Analysis (CA) identified the dominant and potential sources of contaminants in the groundwater aquifer, including geogenic, salinity intrusion, industrial, and agricultural. The results of the degree of contamination level (Cd) and the heavy metal pollution index (HPI) showed that 28% and 12% of the sampling points had high levels of heavy metal contamination, indicating a high risk for human health issues. Cr concentrations were found to have a higher carcinogenic (cancer) risk than As and Cd concentrations. Hazard quotient (HQ) and hazard index (HI) scores expressed the hazardous status and possible chronic effects in the context of individual sampling points. For both child and adults, 44% and 36% of the sampling points had a high HI score, indicating the possibility of long-term health risks for local populations.

Cp*Co(III) -Catalyzed C(sp(3) )-H Bond Amidation of 8-Methylquinoline.

An efficient and external oxidant-free, Cp*Co(III) -catalyzed C(sp(3) )-H bond amidation of 8-methylquinoline, using oxazolone as an efficient amidating agent, is reported for the first time under mild conditions. The reaction is selective and tolerates a variety of functional groups. Based on previous reports and experimental results, the deprotonation pathway proceeds through an external base-assisted concerted metalation and deprotonation process.