In order to teach students,the importance of conductometric titrations in this work,we present a laboratory experiment to quantify the amount of metformin hydrochloride in a tablet.The quantification was carried out t...In order to teach students,the importance of conductometric titrations in this work,we present a laboratory experiment to quantify the amount of metformin hydrochloride in a tablet.The quantification was carried out through the evaluation of the chloride by silver nitrate.The titration and the end point were followed by conductometric titration,as well as by potentiometric and visually by the Volhard method.In addition,the theoretical conductivities of the metformin hydrochloride solution were calculated when known volumes of titrant are added,using the limit conductivity data for each of the ions present in the literature.To simulate the conductometric titration,the calculated conductivity values were plotted based on the volume of silver nitrate added.A comparison between techniques is made in order to determine the best monitoring method,being this one conductimetry to detect the equivalence point for metformin hydrochloride with 0.99±0.03,according to relative standard deviation(%RSD).Simulated titration curves adequately describe obtained results in an experimental way.The conductometric titration is the best method for quantification since it shows less dispersion between obtained results and has the highest concordance among results.Their application is shown through the analysis and conductometric titration simulations.展开更多
Coronaviruses are widely transmissible between humans and animals, causing diseases of varying severity. Porcine enteric alphacoronavirus(PEAV) is a newly-discovered pathogenic porcine enteric coronavirus in recent ye...Coronaviruses are widely transmissible between humans and animals, causing diseases of varying severity. Porcine enteric alphacoronavirus(PEAV) is a newly-discovered pathogenic porcine enteric coronavirus in recent years, which causes watery diarrhea in newborn piglets. The host inflammatory responses to PEAV and its metabolic regulation mechanisms remain unclear, and no antiviral studies have been reported. Therefore, we investigated the pathogenic mechanism and antiviral drugs of PEAV. The transcriptomic analysis of PEAV-infected host cells revealed that PEAV could upregulate lipid metabolism pathways. In lipid metabolism, steady-state energy processes, which can be mediated by lipid droplets(LDs), are the main functions of organelles. LDs are also important in viral infection and inflammation. In infected cells, PEAV increased LD accumulation, upregulated NF-κB signaling, promoted the production of the inflammatory cytokines IL-1β and IL-8, and induced cell death. Inhibiting LD accumulation with a DGAT-1 inhibitor significantly inhibited PEAV replication, downregulated the NF-κB signaling pathway, reduced the production of IL-1β and IL-8, and inhibited cell death. The NF-κB signaling pathway inhibitor BAY11-7082 significantly inhibited LD accumulation and PEAV replication. Metformin hydrochloride also exerted anti-PEAV effects and significantly inhibited LD accumulation, downregulated the NF-κB signaling pathway, reduced the production of IL-1β and IL-8, and inhibited cell death. LD accumulation in the lipid metabolism pathway therefore plays an important role in the replication and pathogenesis of PEAV, and metformin hydrochloride inhibits LD accumulation and the inflammatory response to exert anti-PEAV activity and reducing pathological injury. These findings contribute new targets for developing treatments for PEAV infections.展开更多
文摘In order to teach students,the importance of conductometric titrations in this work,we present a laboratory experiment to quantify the amount of metformin hydrochloride in a tablet.The quantification was carried out through the evaluation of the chloride by silver nitrate.The titration and the end point were followed by conductometric titration,as well as by potentiometric and visually by the Volhard method.In addition,the theoretical conductivities of the metformin hydrochloride solution were calculated when known volumes of titrant are added,using the limit conductivity data for each of the ions present in the literature.To simulate the conductometric titration,the calculated conductivity values were plotted based on the volume of silver nitrate added.A comparison between techniques is made in order to determine the best monitoring method,being this one conductimetry to detect the equivalence point for metformin hydrochloride with 0.99±0.03,according to relative standard deviation(%RSD).Simulated titration curves adequately describe obtained results in an experimental way.The conductometric titration is the best method for quantification since it shows less dispersion between obtained results and has the highest concordance among results.Their application is shown through the analysis and conductometric titration simulations.
基金funded by the National Natural Science Foundation of China(32102646)the Natural Science Foundation of Guangdong Province,China(2020A1515110315)+1 种基金the Start-up Research Project of Maoming Laboratory,China(2021TDQD002)the China Agriculture Research System of MOF and MARA(cars-35)。
文摘Coronaviruses are widely transmissible between humans and animals, causing diseases of varying severity. Porcine enteric alphacoronavirus(PEAV) is a newly-discovered pathogenic porcine enteric coronavirus in recent years, which causes watery diarrhea in newborn piglets. The host inflammatory responses to PEAV and its metabolic regulation mechanisms remain unclear, and no antiviral studies have been reported. Therefore, we investigated the pathogenic mechanism and antiviral drugs of PEAV. The transcriptomic analysis of PEAV-infected host cells revealed that PEAV could upregulate lipid metabolism pathways. In lipid metabolism, steady-state energy processes, which can be mediated by lipid droplets(LDs), are the main functions of organelles. LDs are also important in viral infection and inflammation. In infected cells, PEAV increased LD accumulation, upregulated NF-κB signaling, promoted the production of the inflammatory cytokines IL-1β and IL-8, and induced cell death. Inhibiting LD accumulation with a DGAT-1 inhibitor significantly inhibited PEAV replication, downregulated the NF-κB signaling pathway, reduced the production of IL-1β and IL-8, and inhibited cell death. The NF-κB signaling pathway inhibitor BAY11-7082 significantly inhibited LD accumulation and PEAV replication. Metformin hydrochloride also exerted anti-PEAV effects and significantly inhibited LD accumulation, downregulated the NF-κB signaling pathway, reduced the production of IL-1β and IL-8, and inhibited cell death. LD accumulation in the lipid metabolism pathway therefore plays an important role in the replication and pathogenesis of PEAV, and metformin hydrochloride inhibits LD accumulation and the inflammatory response to exert anti-PEAV activity and reducing pathological injury. These findings contribute new targets for developing treatments for PEAV infections.