Imputation method for dropout in single-cell transcriptome data / 生物医学工程学杂志

Single-cell transcriptome sequencing (scRNA-seq) can resolve the expression characteristics of cells in tissues with single-cell precision, enabling researchers to quantify cellular heterogeneity within populations with higher resolution, revealing potentially heterogeneous cell populations and the dynamics of complex tissues. However, the presence of a large number of technical zeros in scRNA-seq data will have an impact on downstream analysis of cell clustering, differential genes, cell annotation, and pseudotime, hindering the discovery of meaningful biological signals. The main idea to solve this problem is to make use of the potential correlation between cells and genes, and to impute the technical zeros through the observed data. Based on this, this paper reviewed the basic methods of imputing technical zeros in the scRNA-seq data and discussed the advantages and disadvantages of the existing methods. Finally, recommendations and perspectives on the use and development of the method were provided.

Diagnosis of Papillary Carcinoma of Ampulla by Contrast-Enhanced Spiral CT after Low Tension and Drinking Water / 实用放射学杂志

Objective To explore the diagnostic value of contrast-enhanced spiral CT after low tension and drinking water in papillary carcinoma of ampulla. Methods CT manifestations of papillary carcinoma of ampulla comfirmed pathologically in 20 cases were analysed retrospectively emphasized in artery phase on contrast CT which was performed after injecting 654-2 20 mg and drinking 300~500 ml water.Results Of all the cases , only 2 cases showed tumor filling defect in the descending part of duedenum nearby pancreas on routine CT, but all the cases showed more or less tumor filling defect on contrast-enhanced spiral CT . The diameters of the tumor were between 0.8 to 2.6 cm,2 cases with head of pancreas affected,the diameters of the tumor were between 2.4 to 2.6 cm.There were 2 cases with lymph node metastasis nearby duedenum.All the cases showed expansion of gallbladder ,intrahepatic duct and choledochus expanding in the liver. Conclusion Contrast-enhanced spiral CT after low tension and drinking water is superior to routine CT in determining the size and morphosis of tumor.