Do Neural Nets Learn Statistical Laws behind Natural Language?

The performance of deep learning in natural language processing has been spectacular, but the reasons for this success remain unclear because of the inherent complexity of deep learning. This paper provides empirical evidence of its effectiveness and of a limitation of neural networks for language engineering. Precisely, we demonstrate that a neural language model based on long short-term memory (LSTM) effectively reproduces Zipf's law and Heaps' law, two representative statistical properties underlying natural language. We discuss the quality of reproducibility and the emergence of Zipf's law and Heaps' law as training progresses. We also point out that the neural language model has a limitation in reproducing long-range correlation, another statistical property of natural language. This understanding could provide a direction for improving the architectures of neural networks.Comment: 21 pages, 11 figure

Topological impact of noncanonical DNA structures on Klenow fragment of DNA polymerase

Noncanonical DNA structures that stall DNA replication can cause errors in genomic DNA. Here, we investigated how the noncanonical structures formed by sequences in genes associated with a number of diseases impacted DNA polymerization by the Klenow fragment of DNA polymerase. Replication of a DNA sequence forming an i-motif from a telomere, hypoxia-induced transcription factor, and an insulin-linked polymorphic region was effectively inhibited. On the other hand, replication of a mixed-type G-quadruplex (G4) from a telomere was less inhibited than that of the antiparallel type or parallel type. Interestingly, the i-motif was a better inhibitor of replication than were mixed-type G4s or hairpin structures, even though all had similar thermodynamic stabilities. These results indicate that both the stability and topology of structures formed in DNA templates impact the processivity of a DNA polymerase. This suggests that i-motif formation may trigger genomic instability by stalling the replication of DNA, causing intractable diseases

Enantiomer-selective Anti-influenza Activity of Bakuchiol

Background: Novel therapeutic approaches against influenza are required. Bakuchiol is a phenolic isoprenoid found in Babchi seeds. Results: Bakuchiol enantiomer-selectively inhibited influenza A viral infection and growth and activated the Nrf2 pathway. Conclusion: Bakuchiol showed novel enantiomer-selective anti-influenza viral activity. Significance: The study of bakuchiol will contribute to the development of novel approaches to influenza therapy

Effects of a trauma center on early mortality after trauma in a regional city in Japan: a population-based study

Background: Although the effects of the trauma center(TC) were researched in several studies, there have been few studies on changes in the regional mortality due to the implementation of a TC.An emergency medical center (EMC) and TC were implemented at Nagasaki University Hospital (NUH) for the first time in the Nagasaki medical region of Japan in April 2010 and October 2011, respectively, and they have cooperated with each other in treating trauma patients. The purpose of this study was to investigate the effects on the early mortality at population level of a TC working in cooperation with an EMC. Methods: This is a retrospective study using standardized regional data (ambulance service record) in Nagasaki medical region from April 2007 through March 2017. We included 19,045 trauma patients directly transported from the scene. The outcome measures were prognosis for one week. To examine the association between the implementation of the EMC and TC and mortality at a region, we fit adjusted logistic regression models. Results: The number of patients of each fiscal year increased from 1492 in 2007 to 2101 in 2016.The number of all patients transported to NUH decreased until 2009 to 70, but increased after implementation of the EMC and TC. Overall mortality of all patients in the region improved from 2.3% in 2007 to 1.0% in 2016.In multivariate logistic regression model, odds ratio of death was significantly smaller at 2013 and thereafter if the data from 2007 to 2011 was taken as reference. Conclusions: Implementation of the EMC and TC was associated with early mortality in trauma patients directly transported from the scene by ambulance. Our analysis suggested that the implementation of EMC and TC contributed to the improvement of the early mortality at a regional city with 500000 populations. Level of evidence: Level III