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In this study, an ensemble of fine-tuned convolutional neural networks (CNNs) is proposed. As CNN training requires large annotated data, which are lacking in the field of urine sediment microscopic image processing, the authors first pre-trained the CNNs, including ResNet50 and GoogLeNet, and developed AlexNet on an ImageNet dataset. Thereafter, some of the weights of the pre-trained CNNs were transferred to the urine sediment microscopic image dataset. To guide fine-tuning of the learning rate and cascading features, the hierarchical nature of features in different convolutional layers was investigated by visualising the CNN. Then, they combined three CNNs as an ensemble of CNNs to decrease the differences and impurity interference among features of urine sediment microscopic image. These fusion features were employed to train the fully connected neural network for classification. In this study, they improved the accuracy of each CNN by an average of 2.2% through fine-tuning of the learning rate and cascading features. Moreover, the better experimental results were achieved compared with other state-of-the-art methods and indicated that a 97% classification accuracy can be attained. [ABSTRACT FROM AUTHOR]

The massive construction of high-speed rail has profoundly changed China, and it has also had a significant impact on air pollution in Chinese cities. Based on the panel data of 278 cities in China from 2003 to 2019, this paper makes an empirical study on the influence of high-speed rail on city-level air quality by using the opening of high-speed rail as a quasi-natural experiment and taking the method of progressive DID estimation model. The results show that: 1) The opening of high-speed rail significantly improves city-level air quality, and the conclusions are still valid after a series of robustness tests and dealing with endogenous problems. 2) The opening of high-speed rail has a heterogeneous effect on air quality in cities of different regions and different scales. 3) The opening of high-speed rail can promote technological progress and accelerate the upgrading of industrial structures, as well as reduce air pollution levels in neighboring cities through the spillover effect. 4) The opening of high-speed rail improves urban air quality through the substitution effect of air passenger transport. [ABSTRACT FROM AUTHOR]

P450 (cytochrome P450) is a supergene family, which is involved in various metabolic pathways in plants. Based on previous study, we found some of cucumber P450 mRNAs were systemic mobile in cucumber/pumpkin grafts. However, the reason that why P450 mRNAs were endorsed as signaling, and what specific motif (s) did they harbored is not clear yet. Here, we first identified 221 CsaP450 genes in cucumber genomewide level. Combining with graft-transmissible mRNAs datasets in cucumber, we elucidated 15 mobile-CsaP450 -coding genes, of which 5 and 10 belonged to A-type and non-A type respectively. Compared with Arabidopsis and pumpkin (Cucubit moschata) graft-induced-transmissible P450 mRNAs, a phylogenetic tree was constructed and divided into eight clans by using multiple-sequence alignment. Gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) annotations indicated that the expression patterns of the mobile-mRNA-coding CsaP450 genes in different tissues of cucumber was specifically enriched in oxidoreductase activity and secondary metabolic pathways. The structures and motifs of these 15 mobile-mRNA-coding CsaP450 genes and their types of regulatory elements told that the proportion of CU-rich motifs was higher than nonmobile-mRNA-coding CsaP450 genes. The integrated analysis of mobility direction and mRNA abundance of 15 mobilemRNA-coding CsaP450 genes allowed to conclude that there was rarely relationship between them. The study provided a new insight into the relationship between the motifs and functional characterization of mobile-mRNA-coding P450 genes of cucumber in genome-wide levels. [ABSTRACT FROM AUTHOR]

Background: Hepatitis A virus is the causative agent of type A viral hepatitis, which causes occasional acute hepatitis. Nevertheless, little information about synonymous codon usage pattern of HAV genome in the process of its evolution is available. In this study, the key genetic determinants of codon usage in HAV were examined. Results: The overall extent of codon usage bias in HAV is high in Picornaviridae. And the patterns of synonymous codon usage are quite different in HAV genomes from different location. The base composition is closely correlated with codon usage bias. Furthermore, the most important determinant that results in such a high codon bias in HAV is mutation pressure rather than natural selection. Conclusions: HAV presents a higher codon usage bias than other members of Picornaviridae. Compositional constraint is a significant element that influences the variation of synonymous codon usage in HAV genome. Besides, mutation pressure is supposed to be the major factor shaping the hyperendemic codon usage pattern of HAV. [ABSTRACT FROM AUTHOR]

As an oral chemotherapy prodrug, tegafur, can be converted to 5-fluorouracil, which is activated to kill tumor cells mainly by the inhibition of thymidylate synthase. In the present study, we synthesized 20 new tegafur derivatives containing amino acid ester groups by substitution, hydrolysis, and condensation. Their structures were confirmed by ¹H NMR, 13C NMR, and H RMS, and their inhibitory effects on tumor cell growth were studied. The results showed that some of the compounds had good anti-tumor activity. [ABSTRACT FROM AUTHOR]