Search

Abstract: We have developed models to investigate the power properties of monolithic fiber laser with master oscillator multi-stage power amplifiers configuration. In the simulation the effect of optical characteristics of fiber fusion splice was considered, which was introduced by connecting fiber amplifiers. The theoretical modeling was established based on the classic theory of rate equations and the computational method was described in detail. On the basis of three high-power fiber lasers with different structures, we analyzed the splice loss and return loss, and how they influence the distribution of laser power in the system. The results showed that, on the present splicing level, both the enhancement of the pump capacity of fiber laser and the reduction of the quantity of power amplifier modules were effective strategies to accomplish fiber laser with tens of thousands of watts output. [Copyright &y& Elsevier]

Comprehensive Summary: Five new pyrrolizidine alkaloids, bohemamines J—N (1—5), were isolated from Streptomyces sp. CPCC 200497. Their structures were assigned based on detailed spectroscopic analysis and semisynthesis. Bohemamine J (1) possesses a new chimeric skeleton derived from bohemamine A (6) and phenylacetaldehyde. Inspired by the nonenzymatic formation mechanism of the methylene‐bridged dimers isolated from this strain, we synthesized a series of chimeric derivatives (8, 9, and 12—23) through natural product chimera strategy. Compounds 13, 15, 19, and 21 showed significant antioxidant activity. [ABSTRACT FROM AUTHOR]

Background: Gastric cancer is a highly prevalent cancer type and the underlying molecular mechanisms are not fully understood. Ubiquitin-specific peptidase (USP) 29 has been suggested to regulate cell fate in several types of cancer, but its potential role in gastric carcinogenesis remains unclear. Methods: The expression of USP29 in normal and gastric cancer tissues was analyzed by bioinformatics analysis, immunohistochemistry and immunoblot. Gene overexpression, CRISPR-Cas9 technology, RNAi, and Usp29 knockout mice were used to investigate the roles of USP29 in cell culture, xenograft, and benzo[a]pyrene (BaP)-induced gastric carcinogenesis models. We then delineated the underlying mechanisms using mass spectrometry, co-immunoprecipitation (Co-IP), immunoblot, ubiquitination assay, chromatin immunoprecipitation (ChIP), quantitative real-time PCR (qRT-PCR), and luciferase assays. Results: In this study, we found that USP29 expression was significantly upregulated in gastric cancers and associated with poor patient survival. Ectopic expression of USP29 promoted, while depletion suppressed the tumor growth in vitro and in vivo mouse model. Mechanistically, transcription factor far upstream element binding protein 1 (FUBP1) directly activates USP29 gene transcription, which then interacts with and stabilizes aurora kinase B (AURKB) by suppressing K48-linked polyubiquitination, constituting a FUBP1-USP29-AURKB regulatory axis that medicates the oncogenic role of USP29. Importantly, systemic knockout of Usp29 in mice not only significantly decreased the BaP-induced carcinogenesis but also suppressed the Aurkb level in forestomach tissues. Conclusions: These findings uncovered a novel FUBP1-USP29-AURKB regulatory axis that may play important roles in gastric carcinogenesis and tumor progression, and suggested that USP29 may become a promising drug target for cancer therapy. [ABSTRACT FROM AUTHOR]

Several studies have reported that ulvan from the alga Ulva pertusa (Chlorophyta) exhibits substantial antioxidant and antihyperlipidemic activities; however, which group of heteropolysaccharides play roles in these activities remains unknown. In this study, three purified ulvan (PU1, PU2 and PU3) have been obtained by DEAE-Sepharose fast-flow column. The antioxidant activity was detected via the model of hyperlipidemic Kunming mice, including malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) in liver. PU3, which possessed the highest uronic acid content (24.09%) and sulfate content (23.99%) as well as the lowest average molecular weight (83,094 Da), exhibited the stronger antioxidant activity than other examples. It significantly decreased MDA (29.2%; P  < 0.05), increased SOD (36.4%; P  < 0.05) and CAT (43.6%; P  < 0.05) compared with hyperlipidemia group. In conclusion, PU3 may be potential sources of natural antioxidant to protecting against the liver damage of oxidative stress induced by cholesterol-rich diet. [ABSTRACT FROM AUTHOR]