Immunoglobulin A (IgA) is the main antibody isotype secreted into the intestinal lumen. IgA plays a critical role in the defence against pathogens and in the maintenance of intestinal homeostasis. However, how secreted IgA regulates gut microbiota is not completely understood. In this study, we isolated monoclonal IgA antibodies from the small intestine of healthy mouse. As a candidate for an efficient gut microbiota modulator, we selected a W27 IgA, which binds to multiple bacteria, but not beneficial ones such as Lactobacillus casei. W27 could suppress the cell growth of Escherichia coli but not L. casei in vitro, indicating an ability to improve the intestinal environment. Indeed W27 oral treatment could modulate gut microbiota composition and have a therapeutic effect on both lymphoproliferative disease and colitis models in mice. Thus, W27 IgA oral treatment is a potential remedy for inflammatory bowel disease, acting through restoration of host-microbial symbiosis.

Engineering use of jointed materials requires quantitative inspection of the joints, though it has not been established yet. Electromagnetic acoustic transducers (EMATs) can generate and detect ultrasonic waves in a conductive specimen by electromagnetic coupling without any contact with a specimen. This feature gives EMATs an advantage over conventional ultrasonic transducers: theoretical modeling and formulation based on elastodynamics and electromagnetics can be obtained. In this research, a process of joint inspection using EMATs was analyzed numerically. Numerical results of the wave propagation explain effects of the joint interface and of a joint failure on the propagation of ultrasonic waves and on the receiver signals, in terms of reflection and diffraction of the waves. Predicted receiver signals agree well with experimental results, which verifies our numerical approach. These results show a possibility of quantitative joint inspection using EMATs.

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