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ObjectiveTo investigate the clinical value of acoustic radiation force impulse (ARFI) elastography in predicting esophageal variceal bleeding in patients with liver cirrhosis. MethodsA retrospective analysis was performed for the clinical data of 271 patients with liver cirrhosis who attended the Fifth Medical Center of Chinese PLA General Hospital from October 2014 to May 2017, and ARFI elastography was performed for all patients to measure the elasticity of the liver and the spleen. According to the presence or absence of esophageal variceal bleeding, the patients were divided into bleeding group and non-bleeding group, and related indices were compared between the two groups. The receiver operating characteristic (ROC) curve was used to evaluate the value of ARFI elasticity in the diagnosis of esophageal variceal bleeding in liver cirrhosis. The t-test was used for comparison of normally distributed continuous data between two groups, and the Mann-Whitney U test was used for comparison of non-normally distributed continuous data between two groups; the chi-square test was used for comparison of categorical data between two groups. ResultsThe bleeding group had a significantly higher ARFI elasticity of the spleen than the non-bleeding group ［3.89(349-4.11) m/s vs 3.46(2.93-3.80) m/s, Z=-4.941, P＜0.001］, and there was no significant difference in the ARFI elasticity of the liver between the bleeding group and the non-bleeding group ［2.08 (1.57-2.74) m/s vs 1.98 (1.49-2.70) m/s, Z=-1.025, P=0.305］. The areas under the ROC curve for ARFI elasticity values of the spleen and the liver were 0.714 and 0.544, respectively, in predicting esophageal variceal bleeding in patients with liver cirrhosis (P=0.002 5). At the cut-off value of 3.71 m/s, the ARFI elasticity of the spleen had a sensitivity of 0.68 and a specificity of 0.69 in predicting esophageal variceal bleeding. ConclusionThe ARFI elasticity value of the spleen has a better value than that of the liver in predicting the risk of esophageal variceal bleeding and thus holds promise for clinical application.

ObjectiveTo investigate the spleen stiffness of patients with chronic hepatitis and liver cirrhosis by spleen acoustic radiation force impulse (ARFI), aspartate aminotransferase-to-platelet ratio index (APRI), and aspartate aminotransferase/alanine aminotransferase ratio (AAR), as well as the clinical value of these three noninvasive techniques in predicting esophageal varices (EV) in patients with liver cirrhosis. MethodsA total of 247 patients with chronic hepatitis and liver cirrhosis were enrolled, and ARFI was used to measure real-time spleen stiffness. APRI and AAR were calculated. Gastroscopy was performed within one week before and after measurement to clarify the degree of EV. With the results of gastroscopy as the gold standard, the receiver operating characteristic (ROC) curve was used to compare the clinical value of spleen ARFI value, APRI, and AAR in the diagnosis of EV in patients with liver cirrhosis. The t-test was used for comparison of continuous data between two groups. ResultsThere were significant differences between the EV group (n=169) and the non-EV group (n=78) in spleen ARFI stiffness (3.64±0.53 m/s vs 2.97±0.65 m/s, t=-7.93, P＜0.001), APRI (0.87±091 vs 0.52±0.80, t=-2.90, P=0.004), and AAR (1.54±0.67 vs 1.29±0.55, t=-2.93, P=0.004). Spleen ARFI, APRI, and AAR had an area under the ROC curve of 0.80, 0.72, and 0.63, respectively, in predicting EV in patients with liver cirrhosis, there was a significant difference between spleen ARFI stiffness and AAR (P=0.005), while there was no significant difference between spleen ARFI stiffness and APRI (P=0.10). ConclusionARFI is a real-time ultrasound elastography technique, and compared with APRI and AAR, spleen stiffness measured by ARFI can predict EV in patients with chronic hepatitis and liver cirrhosis more accurately and noninvasively and thus holds promise for clinical application.

All proteins are made of 20 different amino acids and there are 4 kinds of nucleotides in the amino acids. Three consecutive nucleotides on the gene which are called triplet codon are used to code an amino acid, and 64 triplet codons compose genetic code table. Central dogma (DNA-RNA-protein) has been acknowledged, but the process and mechanism of mRNA passing through the nuclear membrane still requires further investigation. For these two problems above, we have proposed in this paper a conjecture of nucleotide free triplet of nucleotide and get 20 equivalence classes in the condition of mapping from free triplet vertex set to nucleotide set using group theory. It needs to be considered whether the four numbers 3, 4, 20 and 64 here have relevance inside. Then the numbers 3, 4, 20 and 64 are connected together. It is important for analysis of triplet code and protein composition.

A feature-based algorithm for image mosaics with moving objects is proposed. Firstly, the algorithm eliminates feature points which are selected on moving objects during similarity transform, then outliers are eliminated using RANSAC algorithm. In the image blend phase, difference image between two images is created using homogeneous transformation matrix. Then region growth algorithm is used to segment the moving object region. Finally, a piecewise mapping algorithm for generating panoramic images is utilized. Experimental results show the effectiveness of the algorithm.

After analyzed the feasible solutions of N-queens problem, this paper brought forward the concept of morphological gene and rules to extract morphological genes. It connected dihedral group, morphological gene combination with equivalence class of queens position of N-queens problem, summarized the one eighth rule of N-queens problem, then analyzed the causes for attenuate of one eighth rule from two aspects of group and symmetry of morphological gene combination. It provided a new mentality for further deep research of N-queens problem, and is of reference value for studying highly effective algorithm for N-queens problem.