Preliminary study on screening and diagnosis of fetal cleft palate by two-dimensional combined with three-dimensional ultrasound in early pregnancy / 中华超声影像学杂志

Objective:To explore the feasibility of ultrasound screening and diagnosis of fetal cleft palate in early pregnancy, analyze and summarize the imaging technology and image characteristics of two-dimensional and three-dimensional ultrasound in normal fetus and cleft palate fetus.Methods:A total of 10 519 pregnant women participated in the early pregnancy were included from January 2016 to June 2020 in Shenzhen Hospital, University of Chinese Academy of Sciences. The palatal line on the standard section of fetal nuchal translucency (NT) measurement was used as a screening marker for routine observation. For fetuses with abnormal palatine line, posterior nasal triangle of coronal plane and axial plane of maxillary alveolar arch of two-dimensional ultrasound were added as the diagnostic sections, and three-dimensional volume data of fetal face were collected, and three dimensional multimodal imaging technology was used to analyze the volume data off-line to determine or exclude fetal severe cleft palate. All fetuses were followed up during the second trimester for deformity scanning and post natal (or induced labor) assessment.Results:Of the 10 519 fetuses, the standard NT plane was obtained and the palatal line was observed in 10 204 cases(97.01%), with normal palatal line in 10 169 cases.In 35 suspected cases, 13 cases were confirmed cleft lip and palate by two and three dimensions ultrasound, and were confirmed by induced labor. There were 7 cases in unilateral side, 3 cases in bilateral, 2 cases in median cleft lip and palate, 1 cases in irregular cleft lip and palate, and no false positive results were reported. Twenty-two suspicious cases were excluded by increasing the two-dimensional sectional and three-dimensional volumetric off-line analysis, and screening after the second trimester and after birth. There was 1 case of missed diagnosis of simple cleft palate.Conclusions:Palatal line is a good screening marker for fetal cleft palate in early pregnancy. For fetuses with abnormal palatine line, the adding of posterior nasal triangle and the axial plane of maxillary alveolar arch, and combining three-dimensional volume data for off-line analysis can determine or exclude severe cleft palate. This study is of great significance for early screening and diagnosis of severe fetal cleft palate, prenatal genetic counseling and prevention birth defect.

Research progress of stochastic resonance in neural models / 生物医学工程学杂志

In nonlinear systems, noise can improve the responses of the systems with appropriate noise intensity. This phenomenon is called stochastic resonance. Biological neural systems are noisy and stochastic resonance has been found in them experimentally and theoretically. Now many researches focus on the signal transmission and processing in neural models. So this paper introduces the researches of stochastic resonance in noisy neural models. Then the recent research achievement and progress are reviewed in the following three aspects: noise; the development of stochastic resonance; and neural network. At last, the foreground of the study is discussed.

The effects of high frequency signal investigated in a neuron model / 生物医学工程学杂志

We have investigated the effects of high frequency (HF) signal on firing activity in a biologically realistic system--the noisy Hodgkin-Huxley (HH) neuron model via numerical simulations. The results show that when the HF amplitude to frequency ratio (AFR) increases, the firing rate is diminished and stochastic resonance disappears, even the HH neuron model is processing a stimulus of its most sensitive frequency. When the noise intensity is strong, the vibration resonance can be observed. Moreover, the fluctuation around the resting potential will be replaced by an oscillation of the same high frequency with the increasing AFR. The inhibition of the firing activity is consistent with the results of experiment in vivo that HF current can stop the transmission of action potential in peripheral nerve. This study is of functional significance to the biomedical research on the damages caused by electro-pollution in vivo and signal processing.