Salt signals in tongue are relayed to the nucleus of the solitary tract (NST). This signaling is very important to determine whether to swallow salt-related nutrition or not and suggests some implications in discrimination of salt concentration. Salt concentration-dependent electrical responses in the chorda tympani and the NST were well reported. But salt concentration-dependency and spatial distribution of c-Fos in the NST were not well established. In the present study, NaCl signaling in the NST was studied in urethane-anesthetized rats. The c-Fos immunoreactivity in the six different NST areas along the rostral-caudal axis and six subregions in each of bilateral NST were compared between applications of distilled water and different concentrations of NaCl to the tongue of experimental animals. From this study, salt stimulation with high concentration (1.0 M NaCl) induced significantly higher c-Fos expression in intermediate NST and dorsal-medial and dorsal-middle subregions of the NST compared to distilled water stimulation. The result represents the specific spatial distribution of salt taste perception in the NST.
Animals ; Axis, Cervical Vertebra ; Chorda Tympani Nerve ; Discrimination (Psychology) ; Rats ; Solitary Nucleus ; Taste Perception ; Tongue ; Water

This study was aimed at understanding the genome-wide characterization and variations for three imported novel coronavirus(SARS-CoV-2)strains from different sources in the same period in Jinan at the viral genome level,to provide a sci-entific basis for further improving the prevention and control of COVID-19 outbreaks at Jinan port.We selected nasal and pha-ryngeal swab samples from three cases of imported asymptomatic COVID-19infectionat Jinan port;performed second-genera-tion whole-genome sequencing;and analyzed the variant loci and homology withvarious bioinformatics software.The whole ge-nome sequence of SARS-CoV-2 was successfully obtained from three samples of asymptomatic infected cases,and had full lengths ranging from 29 835 bp to 29 844 bp.Pangolin typing results indicated that the genotypes of the three samples were O-micron BQ.1,BQ.1.1,and BQ.1.12.Compared with the original Wuhan strain,the three samples produced mutations at 77,80,and 78 base sites,respectively,involving 60-63 non-synonymous mutations,mainly in the S and ORF1ab genes.Omicron BQ.1 is an imported variant of the SARS-CoV-2 virus and was detected for the first time at Jinan port.From a molecular biolo-gy perspective,this study provides a theoretical basis for the source tracing and prevention and control of COVID-19 at theport.

Objective: To compare the differences in the stress distribution in simulated first molars prepared with three rotary nickel-titanium instruments. Methods : Four simulated first molars were prepared without instruments and with Reciproc, WaveOne and Protaper. Before and after preparation, each simulated molar was scanned by Micro-CT. The data were imported to Mimics 16.0 software to establish three-dimensional models. Finite element analysis was processed with Abaqus 6.14 software under conditions of longitudinal and lateral load. Results: Under vertical load conditions, the maximum von Mises stress of the enamel increased by 1.36%, 21.48% and 20.99% in the Reciproc, WaveOne and Protaper groups, respectively, after preparation, while the maximum von Mises stress of the cementum increased by 55.98%, 41.18% and 33.04%, respectively, and the maximum von Mises stress of the alveolar bone increased by 45.55%, 40.37% and 24.09%, respectively. Under 45° lateral load conditions, the maximum von Mises stress of the enamel increased by 1.79%, -4.58% and 3.82% in the Reciproc, WaveOne and Protaper groups, respectively, after preparation, while the maximum von Mises stress of cementum increased by 16.33%, 7.58% and 4.32%, respectively, and the maximum von Mises stress of the alveolar bone increased by 46.82%, 36.40% and 8.29%, respectively. Under the same conditions, the von Mises stresses of the cementum and alveolar bones of the simulated molars were higher after preparation than before preparation, especially under lateral load conditions. The stress was focused on the border between the crown and the root. The von Mises stress of the cementum and alveolar bones increased much more in the Reciproc group than in the other two groups under both conditions. Conclusion The von Mises stress of simulated molars was greater after preparation than before preparation. The von Mises stress of the cementum and alveolar bones increased much more in the Reciproc group than in the other two groups.