Interaction of tetradecyltrimethylammonium bromide with bovine serum albumin in different compositions: Effect of temperatures and electrolytes/urea

Herein,the interaction of a protein,bovine serum albumin(BSA),with tetradecyltrimethylammonium bromide(TTAB,a cationic surfactant),has been investigated using the conductivity measurement technique in pure water and some sodium salts(NaCl,Na_(2) SO_(4),Na_(2) CO_(3), and Na_(3) PO_(4)) solutions at temperature range of 295.15-320.15 K.Results reveal that,in the plot of specific conductivity versus the concentration of TTAB,only a single critical micelle concentration(cmc) was found for the TTAB+BSA mixed system in all solvents media studied.The addition of BSA in aqueous TTAB solution,the value of cmc undergoes a change from its pure form,which indicates the presence of strong interaction operating between the BSA and TTAB molecules.In aqueous system,the cmc values of the TTAB+BSA mixtures are obtained higher compared to the values found for single TTAB surfactant However,the addition of salt decreases the cmc value of mixed TTAB+BSA system.The values of cmc of the BSA+TTAB mixed system at 310.15 K and 1.00 mmol·kg^(-1) ionic strength of salt followed the order:cmc_(Na_(2) CO_(3))> Cmcc_(Na_(3) PO_(4))> cmcNaCl>cMC_(Na_(2) SO_(4)).The cmc values of TTAB+BSA mixture were found to be lowered in urea solution within the concentrations studied.The values of degree of dissociation(α) and fraction of counter ion binding(β) were found to be dependent on additives and temperature.The free energy of micellization(AGm) is negative for all the systems,which manifests that the micellization phenomenon is energetically spontaneous.The enhancement of the negative value of △G_(m)^(0) in aqueous salt solutions reveals an increase of spontaneity of the TTAB+BSA micellization process.The values of △G_(m)^(0) also reveal that the spontaneity of micelle formation is enhanced at higher temperatures in all media studied.The values of free energy of transfer(△G_(m,t)^(o)) were also determined for numerous solvent media used in the present study and described with appropriate reasoning.

Revealing the linguistic and geographical disparities of public awareness to Covid-19 outbreak through social media

The Covid-19 has presented an unprecedented challenge to public health worldwide.However,residents in different countries showed diverse levels of Covid-19 awareness during the outbreak and suffered from uneven health impacts.This study analyzed the global Twitter data from January 1st to June 30th,2020,to answer two research questions.What are the linguistic and geographical disparities of public awareness in the Covid-19 outbreak period reflected on social media?Does significant association exist between the changing Covid-19 awareness and the pandemic outbreak?We established a Twitter data mining framework calculating the Ratio index to quantify and track awareness.The lag correlations between awareness and health impacts were examined at global and country levels.Results show that users presenting the highest Covid-19 awareness were mainly those tweeting in the official languages of India and Bangladesh.Asian countries showed more disparities in awareness than European countries,and awareness in Eastern Europe was higher than in central Europe.Finally,the Ratio index had high correlations with global mortality rate,global case fatality ratio,and country-level mortality rate,with 21-31,35-42,and 13–18 leading days,respectively.This study yields timely insights into social media use in understanding human behaviors for public health research.