Analyzing the Effect of Social Distancing Policies on Traffic at Sinchon Station, South Korea, during the COVID-19 Pandemic in 2020 and 2021.

The COVID-19 pandemic is recognized as one of the most serious global health problems, and many countries implemented lockdown measures to mitigate the effects of the crisis caused by this respiratory infectious disease. In this study, we investigated the relationship between social distancing policies and changes in traffic volume in Sinchon Station, South Korea. We used an official COVID-19 report provided by the Korea Disease Control and Prevention Agency (KCDA) and Seoul Metropolitan Government (SMG) to review social distancing policies, and the changes in traffic patterns before and during the COVID-19 pandemic between January 2020 and November 2021 were analyzed. Our study reveals that the changes in the overall traffic patterns from acceleration phases to deceleration phases of COVID-19 were related to the alert levels of social distancing policies implemented to tackle the situation resulting from the COVID-19 pandemic. Herein, we found that a significant decline in traffic volume took place from August to September 2020 (13.5−19.7%, weekday; 19.4−31.7%, weekend), from December 2020 to January 2021 (20.0%−26.6%, weekday; 26.8−34.0%, weekend), and from July to September 2021 (3.2−13.1%, weekday; 38.3−44.7%, weekend) when compared to the corresponding periods in 2019 (paired t-test; p < 0.001). The results of this study provide strong support for the effectiveness of Seoul's preemptive measures, namely, the central government's intensive social distancing campaign, in managing and reducing the impact of the pandemic situation based on the precise analysis of 10 types of facilities.

Chitosan oligosaccharides, dp 2-8, have prebiotic effect on the Bifidobacterium bifidium and Lactobacillus sp.

In order to investigate the prebiotic potential of chitosan oligosaccharide (COS), prepared by enzymatic hydrolysis of fully deacetylated chitosan polymer, the effect of COS on bacterial growth was studied. The degree of polymerization (dp) of COS was determined by MALDI-ToF mass spectrometry, and the COS was found to be composed of dimer (33.6%), trimer (16.9%), tetramer (15.8%), pentamer (12.4%), hexamer (8.3%), heptamer (7.1%), and octamer (5.9%). The minimum inhibitory concentrations (MIC) of chitosan polymer against lactic acid bacteria and bifidobacteria were below 0.31%. However, this only applied to two strains, the other bacteria tested grew on MRS broth containing 5% COS. The effects of COS on the growth of bifidobacteria and lactic acid bacteria were compared with those of fructo-oligosaccharide (FOS). FOS was found to have a growth stimulatory effect on only three strains: Bifidobacterium bifidium, B. infantis and Lactobacillus casei. However, COS stimulated the growth of most Lactobacillus sp. and B. bifidium KCTC 3440. The amount of the growth and the specific growth rate of B. bifidium increased with increasing COS concentration. The cultivation time required to obtain maximum growth was reduced to about 25% in MRS broth supplemented with 0.2-0.4% COS. These results demonstrate that COS has considerable bifidogenic potential. Both cell growth and specific growth rates of L. brevis in MRS broth supplemented with 0.1% COS increased by 25%. The present study shows that COS stimulates the growth of some enteric bacteria, and that COS has potential use as a prebiotic health-food.