Nicotine Regulates Streptococcus mutans Extracellular Polysaccharide and Related Protein Expression

poster abstractStreptococcus mutans, a gram-positive facultatively anaerobic bacterium, is considered as the primary contributor to caries due to its high acidogenicity and aciduricity. Smoking is one of the risk factors of periodontal disease and dental caries. Nicotine is one of the alkaloid pharmacologically active agents in tobacco. Previous studies indicated nicotine stimulated S. mutans biofilm formation and metabolism. However, the detailed mechanism is still unknown. Thus, the aim of this study is to investigate how nicotine facilitates S. mutans biofilm formation focused on extracellular polysaccharide synthesis. S. mutans UA159 (ATCC 700610) was used in the present study. Confocal laser scanning microscopy (CLSM) was used to investigate the effect of 0, 1, 2 and 4 mg/ml nicotine on 24 h S. mutans biofilm extracellular polysaccharide (EPS) expression (red fluorescentlabeled) and nucleic acid expression (green fluorescent-labeled). Western blot assays were used to investigate the effect of 0, 1, 2 and 4 mg/ml nicotine on the expression of glucosyltransferase (Gtfs), glucan-binding protein A (Gbp-A) and Gbp-B in 24 h S. mutans biofilm cells. CLSM results indicated nicotine increased both EPS and nucleic acid, and the ratio of EPS/nucleic acid was also increased. It implied EPS synthesis in single S. mutans cells was stimulated by nicotine treatment. Biofilm thickness was thicker in nicotine-treated groups than the non-treated group. Western blot assay results indicated that nicotine stimulated GtfC, Gbp-A and Gbp-B expression, but decreased GtfB expression. In conclusion, nicotine stimulates S. mutans cell proliferation and EPS synthesis partially by increasing GtfC, Gbp-A and Gbp-B

The Simulation of Rockfill in a Characteristic of Three-Dimensional Strength

To study the three-dimensional strength characteristics of rockfill material under an anisotropic state, the anisotropic state variables were introduced into the Mohr-Coulomb failure criterion, and the failure criterion describing the three-dimensional strength of rockfill which was obtained in linear form in this paper. The anisotropic state variables were established with the fabric of rockfill particles. Based on the experimental results of a large triaxial consolidated drained test, fractal dimension theory was introduced to study the relationship between strength and deformation characteristics under different gradation and confining pressures. The experimental results and simulation have shown that: (1) The fractal theory can be used to quantitatively describe the rockfill particles crushing with all kinds of grades under different stress levels. (2) The fabric of rockfill particles was closely related to the three-dimensional strength characteristics. (3) The anisotropic state variables can describe the three-dimensional strength characteristics of rockfill well from a microscopic perspective

Efficient Multimodal Fusion via Interactive Prompting

Large-scale pre-training has brought unimodal fields such as computer vision and natural language processing to a new era. Following this trend, the size of multi-modal learning models constantly increases, leading to an urgent need to reduce the massive computational cost of finetuning these models for downstream tasks. In this paper, we propose an efficient and flexible multimodal fusion method, namely PMF, tailored for fusing unimodally pre-trained transformers. Specifically, we first present a modular multimodal fusion framework that exhibits high flexibility and facilitates mutual interactions among different modalities. In addition, we disentangle vanilla prompts into three types in order to learn different optimizing objectives for multimodal learning. It is also worth noting that we propose to add prompt vectors only on the deep layers of the unimodal transformers, thus significantly reducing the training memory usage. Experiment results show that our proposed method achieves comparable performance to several other multimodal finetuning methods with less than 3% trainable parameters and up to 66% saving of training memory usage.Comment: Camera-ready version for CVPR202

Effect of Green Tea on Streptococcus mutans Metabolic Activity, Planktonic Growth, and Biofilm Activity in the Presence of Nicotine

poster abstractStreptococcus mutans is the main bacterial cause of dental caries, and it has been proven by previous research that its growth is affected by various concentrations of nicotine and other agents. The amount of S. mutans in the mouth is directly proportional to the number of dental cavities. Studies have shown that smokers have an increased amount of caries, much of which is due to the low concentrations of nicotine the mouth is exposed to. It is known that S. mutans thrives in low-moderate concentrations of nicotine, and that nicotine is a promoting agent for S. mutans. S. mutans has also been proven as a contributor to atherosclerosis, resulting from dental plaque entering the bloodstream. Green Tea is a commonly consumed beverage, which has been known to reduce the number of dental cavities. Previous research has concluded that green tea contains polyphenols, which have antimicrobial effects, including an inhibitory effect on S. mutans. The objective of this research is to observe how green tea affects S. mutans metabolic activity, as well as biofilm and planktonic growth, in the presence of nicotine. The experiments compared S. mutans treated with nicotine concentrations (0-8 mg/ml), and S. mutans treated with a 2.5 g/200 mL concentration of Sencha Jade Reserve Japanese green tea in conjunction with the various nicotine concentrations. The assays were performed in a microtiter plate; the XTT and biofilm assays measured absorbance, and the planktonic assay measured kinetic growth. The experiments conclude that green tea has an inhibitory effect on nicotine-treated S. mutans metabolic activity and planktonic growth, with higher concentrations of green tea inhibiting more effectively. It was also concluded that green tea increases biofilm formation. These conclusions provide evidence of the inhibitory effect green tea has on nicotine-treated S. mutans, and may indicate a way to reduce the incidence of caries and atherosclerosis