Nutrition impacts of non-solid cooking fuel adoption on under-five children in developing countries

This paper examines the nutrition impacts of using non-solid cooking fuel on under-five children in developing countries.We draw on data from more than 1.12 million children in 62 developing countries from the Demographic and Health Surveys(DHS).Results from both fixed effects(FE)and instrumental variable(IV)estimates show that using non-solid cooking fuel significantly improves the nutrition outcomes of under-five children.Compared with their peers from households mainly using solid fuel,children from households mainly using non-solid fuel exhibit a lower probability of experiencing stunting(by 5.9 percentage points)and being underweight(by 1.2 percentage points).Our further investigation provides evidence for several underlying mechanisms,such as improved indoor air quality,induced reduction in children’s respiratory symptoms,benefits on maternal health,and reduction in maternal time spent on fuel collection or cooking.Heterogenous analyses suggest that the nutrition benefits of using non-solid cooking fuel are more prominent among boys,children above three years old,and those from households of lower socioeconomic status,rural areas,and Southeast Asia.

New insights into the effect of molecular crowding environment induced by dimethyl sulfoxide on the conformation and stability of G-quadruplex

Various structures of G-quadruplex in biosystems play an important role in different diseases and are often regulated by a variety of molecular crowding environments induced by internal and even external factors(e.g.,a solvent).Dimethyl sulfoxide(DMSO),a universal solvent,has been widely used in biological studies and for drug therapy,but little is known regarding its effect on G-quadruplex structure and stability.Here,we report the influence of molecular crowding environment induced by DMSO on the conformation and stability of G-quadruplex structure.We show that the G-quadruplex-forming sequences such as human telomeric sequence,which may have diverse conformations in different environments,tend to convert their topologies to parallel structures under the molecular crowding stimulated by DMSO.Moreover,DMSO can increase the stability of the parallel and antiparallel topologies,especially the parallel G-quadruplex sequence c-kit,but not the hybrid topologies.Further analysis of c-kit using the CD and NMR technique,combined with the unique structural characteristics of c-kit,reveals that the crowding,dehydration and interaction of DMSO are conductive to the formation and stability of the parallel G-quadruplex.The present study suggests that,DMSO,a common solvent used in DNA experiments,may have a nonnegligible influence on the structure and stability of G-quadruplex.

A comparative study of assembly and disassembly process of dimeric and monomeric cyanine dyes with DNA templates

Cyanine dyes have attracted more and more interest due to their controllable assembly and disassembly process with biomolecular templates. The self-assembly of cyanine dye not only depend on the environment, but also on their structures. Here, we report assembly and disassembly of two cyanine dyes,a dimeric cyaine dye(TC-P4) and its corresponding monomer(TC). In PBS, these dyes could form aggregates. The parallel c-myc G-quadruplex as a template causes the transformation of TC-P4 from Haggregates to dimer and monomer; while duplex and single-stranded DNAs could not. The interaction between these DNAs motifs and TC could all induce the appearance of monomer band. Parallel c-myc Gquadruplex could enhance the fluorescence intensity of TC-P4 and TC. The self-assembly and disassembly of TC and TC-P4 could be regulated and used as probes for G-quadruplex recognition from duplex and single-stranded DNAs in solution.

Kinetic characterization of a slow chemical exchange between two sites in N,N-dimethylacetylamide by CEST NMR spectroscopy

Nuclear magnetic resonance(NMR)spectroscopy has provided many powerful tools for the study of dynamic processes.Among the reported methods,chemical exchange saturation transfer(CEST)is more suitable for systems with slow exchange rates,and there will be promising in the detection and dynamic mechanism of metastable substances.It has been widely used in magnetic resonance imaging(MRI),however whether it is applicable in the field of chemical kinetics needs more examples.Here we studied,as a proof of concept,the kinetics of the slow chemical exchange between the two N-methyl protons of N,N-dimethylacetylamide(DMA),exploiting QUantifying Exchange using Z-spectrum(QUEZS)and QUantifying Exchange using Saturation Time(QUEST)methods.It turned out that both of QUEZS and QUEST could give the corresponding exchange rates,showcasing the capability of this method to provide accurate kinetic data under a range of temperatures.Our results clearly demonstrated the reliability of CEST-based techniques as a tool for dynamic kinetics by NMR.

Novel sintering behavior of polystyrene nano-latex particles in filming process

Filming process of polystyrene nano-latex (NPS) particles was studied by a combination of various methods. For a constant annealing time of 1 h, the AFM images showed that the deformation and sintering temperatures for NFS particles were ca. 90 ℃ and 100 ℃ respectively. In spin-lattice relaxation measurements of solid state NMR, it is found that TIL, T1S and /1L/I0 increased significantly after annealing at 90℃ and above. DSC results showed that there was an exothermic peak near Tg after annealing for 1 h at the selected temperatures below 95℃; otherwise, the exothermic peak disappeared after annealing at 100℃ or above. The apparent density of NPS increased suddenly in the temperature range. The results implied that the macromolecules in NPS particles are in a confined state with higher confor-mational energy and less cohensional interactions which are the drive force for the sintering at a lower temperature compared with the multichain PS particles and the bulk polymer.