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Intestinal microecology refers to the interaction between the host and the microorganisms in the human intestinal tract, which is composed mainly of intestinal flora. Intestinal microflora affects the physiological and pathological changes of the host through metabolic activity and host interaction. Precancerous lesion of liver is a potential benign liver disease, which may lead to malignant transformation of liver. It is the intermediate stage from benign lesion to malignant transformation. Recent studies have shown that intestinal microecology is closely related to the occurrence of precancerous lesions of the liver. This study expounds the interaction of the bridge between intestine and liver, the gutliver axis, the intestinal microecology and the precancerous lesions of liver, hoping to provide a new idea for clinical prevention and treatment of precancerous lesions of liver.

In order to meet the technical requirements of full ocean depth multibeam echo sounder, the underwater acoustic array must have the ability of wide coverage, broadband response, high sensitivity and high reliability. This paper presents a design of underwater acoustic array based on Mills cross configuration with separate transmitting and receiving units. The arrays have modules design, hence the beamwidth of the array can be adjusted according to particular installation requirements. The working frequency band of the arrays is between 10.5kHz to 13.5kHz, and the coverage angle can cover -71.6°~71.6°. The Integrated design is used to achieve a wide-angle beam coverage of the planar array, which combines the transducer and the sound baffle together to realize a wide directivity of the array elements. The longitudinal bending transducers are designed to meet the broadband requirements for the transmitting array, which are Tonpilz transducers with flexural radiating head. On the other hand, each element of the receiving array is composed of several hydrophones, which are connected in series to achieve high sensitivity. The double-layer watertight technology is also applied in our design, ensuring stable performance and long service life.

In this letter, we address the problem of wideband sources localization in the near field of the sensor array. It is shown that the spatial sampling rate can be considered as a function of temporal frequency so that wideband sources can be represented in the spatial frequency domain. A computationally efficient localization method is then developed based on the Toeplitz matrices constructed from the frequency-dependent cross-correlation between sensors. This allows us to resolve near field sources with quite a few numbers of sensors. Indeed, the sources can be located with fewer sensors. Finally, the simulation results are presented to validate the performance of the proposed method.