Comparative evaluation of Stevia and Xylitol chewing gum on salivary Streptococcus mutans count ? A pilot study

Stevia is a natural sweetener which is used as sugar substitute. It has been suggested that stevia may be anticariogenic. However, there is limited research in this regard. Hence, the present study was designed to assess reduction in S. mutans in stevia and xylitol chewing gums. The aim of this study is to evaluate the effectiveness of stevia and xylitol chewing gums on salivary Streptococcus mutans count. A randomized triple blinded clinical study with a crossover design included twenty healthy children aged 8-13 years with decayed, missing, and filled teeth (dmft)/DMFT index score ? 3. Before the test, unstimulated saliva was collected. Children divided into Group I and II were given Stevia and Xylitol chewing gums respectively. Saliva samples were then collected at 15 min (just after spitting) and after 1 h. The amount of S. mutans in saliva was evaluated using a selective media (TYCSB). The data were subjected to statistical analysis using statistical software IBM SPSS statistics 20.0 (IBM Corporation, Armonk, NY, USA) Reduction in S. mutans was seen from baseline to 1 hour in both groups in trial and crossover design though intergroup comparison was not statistically significant. There was reduction seen from baseline to 15 minutes and 15 minutes to 1 hour in xylitol and stevia group both in trial and crossover design which was statistically significant. Stevia containing chewing gum is equally effective to Xylitol chewing gum in reducing salivary S. mutans counts

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Abstracts of National Conference on Research and Developments in Material Processing, Modelling and Characterization 2020

This book presents the abstracts of the papers presented to the Online National Conference on Research and Developments in Material Processing, Modelling and Characterization 2020 (RDMPMC-2020) held on 26th and 27th August 2020 organized by the Department of Metallurgical and Materials Science in Association with the Department of Production and Industrial Engineering, National Institute of Technology Jamshedpur, Jharkhand, India. Conference Title: National Conference on Research and Developments in Material Processing, Modelling and Characterization 2020Conference Acronym: RDMPMC-2020Conference Date: 26–27 August 2020Conference Location: Online (Virtual Mode)Conference Organizer: Department of Metallurgical and Materials Engineering, National Institute of Technology JamshedpurCo-organizer: Department of Production and Industrial Engineering, National Institute of Technology Jamshedpur, Jharkhand, IndiaConference Sponsor: TEQIP-