ObjectiveTo analyze and assess the pollution levels of lead （Pb）， cadmium （Cd）， and chromium （Cr） in rural soils of Wanzhou District， Chongqing Municipality， and to provide data support for proposing relevant measures and suggestions. MethodsBased on the soil monitoring data from 2017 to 2021， the ecological risk assessment was conducted by applying the Soil Pollution Risk Control Standard for Agricultural Land of Soil Environmental Quality （for trial implementation） （GB 15168‒2018）， the pollution index method and the potential ecological risk method. ResultsA total of 100 soil samples were collected， with pH values ranged from 3.50 to 8.30， and a mean value of 6.10. The mean values of Pb， Cd， and Cr in the soil were 25.2 mg·kg^-1， 0.310 mg·kg^-1， and 68.6 mg·kg^-1， respectively. Except for Cr， the mean values of other elements exceeded the soil background values. Cd level had the largest coefficient of variation and uneven spatial distribution， with an overall exceedance rate of 30.0%. Pollution levels of Pb and Cr were generally at the alert level， while Cd was generally at a light pollution level. The proportion of Cd pollution levels was higher than that of Pb and Cr， and the difference was statistically significant（χ²=15.015， P=0.001）. The Nemerow comprehensive pollution index in different townships ranged from 0.70 to 2.07， with a median value of 1.10， and was generally at a light pollution level. The potential ecological hazard risk of Cd was relatively high， and was generally at a mild level of hazard. The highest contribution rate in the comprehensive potential ecological hazard index was Cd， accounting for 84.1%. ConclusionThere is a certain degree of Cd pollution and mild ecological risk in rural soils of Wanzhou District. Monitoring and management of Cd pollution in rural soils of Wanzhou District， Chongqing Municipality， should be strengthened.

Computer-aided diagnosis (CAD) systems play a very important role in modern medical diagnosis and treatment systems, but their performance is limited by training samples. However, the training samples are affected by factors such as imaging cost, labeling cost and involving patient privacy, resulting in insufficient diversity of training images and difficulty in data obtaining. Therefore, how to efficiently and cost-effectively augment existing medical image datasets has become a research hotspot. In this paper, the research progress on medical image dataset expansion methods is reviewed based on relevant literatures at home and abroad. First, the expansion methods based on geometric transformation and generative adversarial networks are compared and analyzed, and then improvement of the augmentation methods based on generative adversarial networks are emphasized. Finally, some urgent problems in the field of medical image dataset expansion are discussed and the future development trend is prospected.
Humans ; Diagnosis, Computer-Assisted ; Diagnostic Imaging ; Datasets as Topic

Medical image segmentation based on deep learning has become a powerful tool in the field of medical image processing. Due to the special nature of medical images, image segmentation algorithms based on deep learning face problems such as sample imbalance, edge blur, false positive, false negative, etc. In view of these problems, researchers mostly improve the network structure, but rarely improve from the unstructured aspect. The loss function is an important part of the segmentation method based on deep learning. The improvement of the loss function can improve the segmentation effect of the network from the root, and the loss function is independent of the network structure, which can be used in various network models and segmentation tasks in plug and play. Starting from the difficulties in medical image segmentation, this paper first introduces the loss function and improvement strategies to solve the problems of sample imbalance, edge blur, false positive and false negative. Then the difficulties encountered in the improvement of the current loss function are analyzed. Finally, the future research directions are prospected. This paper provides a reference for the reasonable selection, improvement or innovation of loss function, and guides the direction for the follow-up research of loss function.
Algorithms ; Image Processing, Computer-Assisted

Objective: To investigate the clinical effect and safety of long-acting pegylated interferon-α-2b (Peg-IFN-α-2b) (Y shape, 40 kD) injection (180 μg/week) in the treatment of HBeAg-positive chronic hepatitis B (CHB) patients, with standard-dose Peg-IFN-α-2a as positive control. Methods: This study was a multicenter, randomized, open-label, and positive-controlled phase III clinical trial. Eligible HBeAg-positive CHB patients were screened out and randomized to Peg-IFN-α-2b (Y shape, 40 kD) trial group and Peg-IFN-α-2a control group at a ratio of 2:1. The course of treatment was 48 weeks and the patients were followed up for 24 weeks after drug withdrawal. Plasma samples were collected at screening, baseline, and 12, 24, 36, 48, 60, and 72 weeks for centralized detection. COBAS® Ampliprep/COBAS® TaqMan® HBV Test was used to measure HBV DNA level by quantitative real-time PCR. Electrochemiluminescence immunoassay with Elecsys kit was used to measure HBV markers (HBsAg, anti-HBs, HBeAg, anti-HBe). Adverse events were recorded in detail. The primary outcome measure was HBeAg seroconversion rate after the 24-week follow-up, and non-inferiority was also tested. The difference in HBeAg seroconversion rate after treatment between the trial group and the control group and two-sided confidence interval (CI) were calculated, and non-inferiority was demonstrated if the lower limit of 95% CI was > -10%. The t-test, chi-square test, or rank sum test was used according to the types and features of data. Results: A total of 855 HBeAg-positive CHB patients were enrolled and 820 of them received treatment (538 in the trial group and 282 in the control group). The data of the full analysis set showed that HBeAg seroconversion rate at week 72 was 27.32% in the trial group and 22.70% in the control group with a rate difference of 4.63% (95% CI -1.54% to 10.80%, P = 0.1493). The data of the per-protocol set showed that HBeAg seroconversion rate at week 72 was 30.75% in the trial group and 27.14% in the control group with a rate difference of 3.61% (95% CI -3.87% to 11.09%, P = 0.3436). 95% CI met the non-inferiority criteria, and the trial group was non-inferior to the control group. The two groups had similar incidence rates of adverse events, serious adverse events, and common adverse events. Conclusion In Peg-IFN-α regimen for HBeAg-positive CHB patients, the new drug Peg-IFN-α-2b (Y shape, 40 kD) has comparable effect and safety to the control drug Peg-IFN-α-2a.

Objective To screen promoter binding protein of cyclin B2 by using human liver cDNA library, and investigate the expression and regulation mechanism of cyclin B2 gene. Methods By using cyclin B2 biotinylated promoter DNA as the selective molecule, the T7select human liver cDNA library was biopanned and positive clones were selected. After screening, positive plaques were performed to amplify for inserted DNA fragment, and the DNA fragment was cloned into pGEM-Teasy vector. Results Sequence analysis was performed in 20 positive plaques, and the full length sequences were obtained with bioinformatics method and searched for homologous DNA sequence from GenBank, altogether 6 coding sequences were obtained, all of which were known ones. Conclusion Cyclin B2 promoter binding proteins were screened. The results will be useful for further study the expression and regulation mechanism of cyclin B2.

Objective To clone and identify human genes transactivated by homo sapiens HCV FTP2 by constructing a cDNA subtractive library with suppression subtractive hybridization tech- nique.Methods Suppression subtractive hybridization(SSH)and bioinformatics techniques were used for screening and cloning of the target genes transactivated by HCV FTP2.The mRNA was iso- lated from HepG2 cells transfected pcDNA3.1(-)-HCV FTP2 and pcDNA3.1(-)empty vector re- spectively,and SSH method was employed to analyze the differentially expressed DNA sequence be- tween the two groups.After digestion with restriction enzyme Rsa I,small-size cDNAs were ob- tained.Then tester cDNA was divided into two groups and ligated to the specific adaptor I and adap- tor 2 respectively.After tester cDNA was hybridized with driver cDNA twice and underwent two times of nested PCR and then was subcloned into T/A plasmid vectors to set up the subtractive library. Amplification of the library was carried out with E.coli strain DH5?.Futhermore,the cDNA was se- quenced and analyzed in GenBank with Blast search after PCR.Results The subtractive library of genes transactivated by HCV FTP2 was constructed successfully.The amplified library contains 71 positive clones.Colony PCR shows that 56 clones contain 200～1000 hp inserts.Sequence analysis was performed in 24 clones randomly,and the full length sequences were obtained with bioinformatics method.Altogether 20 coding sequences in total were obtained,consisting of 19 known and 1 un- known.Conclusion The obtained sequences may be target genes transactivated by HCV FTP2,and some genes coding proteins involved in cell cycle regulation,metabolism and cell apoptosis.

Objective To construct prokaryotic expression vector of XTP3 gene and induce the expression of fusion protein in E.coli,and prepare XTP3-specific rabbit polyclonal antibody,detect the specificity of the antibody in hepatic carcinoma tissue and normal liver tissue.Methods DNA fragment of XTP3 amplified by PCR was inserted into pET-32a(+) to construct prokaryotic expression vector pET-32a(+)-XTP3.After identified by sequencing,pET-32a(+)-XTP3 was transformed into E.coli BL21 and induced with IPTG.After analyzed by SDS-PAGE and Western blotting,the induced expression product was purified and renatured by Ni+ affinity column chromatography.The purified protein was used to immunize New Zealand rabbits to gain polyclonal antibody,and the polyclonal antibody was then detected by ELISA,immunohistochemistry and Western blotting.Results Prokaryotic expression vector pET-32a(+)-XTP3 was successfully constructed,and the XTP3 fusion protein of about 52kD was highly expressed in E.coli.DS-PAGE showed that the protein product was mainly in inclusion body.The purified protein and polyclonal antibody were obtained successfully.It was manifested by ELISA that the titer of polyclonal antibody was over 1∶128 000.Immunohistochemistry showed that XTP3 antibody presented membrane-positive in hepatic carcinomous tissue.Conclusions The recombinant XTP3 protein and polyclonal antibody have been obtained successfully.These results lay a foundation for studying the immuneogenicity and bionomics of XTP3 protein.