[Research Method of Fatigue Performance of Surgically Implanted Heart Valve Stent].

The aim of this study was to evaluate the fatigue property in vitro of a domestic surgically implanted heart valve stent (SIHVS). The domestic SIHVS was used as a testing sample, and a protocol was developed according to the standards GB 12279-2008 and ISO 5840-2:2015. A dynamic fatigue testing machine was used to apply for a 0.365 mm cyclic radial displacement at the end of the SIHVS. The SIHVS were observed after 400 million cycles by a scanning electron microscope. The observed results show that the structure of SIHVS is intact. There are no fracture, no obvious wear, and no loosening of the wire and casing. In the tested stents, no structural distortion, no cracks and obvious pits were observed. This study demonstrated that SIHVS structure meets the expected fatigue performance requirements.

Pseudomonas abyssi sp. nov., isolated from the abyssopelagic water of the Mariana Trench.

A novel heterotrophic, Gram-stain-negative, aerobic, rod-shaped bacterium, designated as strain MT5T, was isolated from deep seawater in the Mariana Trench and characterized phylogenetically and phenotypically. Bacterial optimal growth occurred at 28 °C (range, 4-45 °C), pH 5-7 (pH 4-11) and with 3-7 % (w/v) NaCl (0-18 %). Phylogenetic analysis based on 16S rRNA gene sequence showed that strain MT5T was related to members of the genus Pseudomonas and shared the highest sequence identities with Pseudomonas pachastrellae CCUG 46540T (99.6 %), Pseudomonas aestusnigri VGXO14T (98.5 %) and Pseudomonas oceani KX 20T (98.4 %). The 16S rRNA gene sequence identities between strain MT5T and other members of the genus Pseudomonas were below 96.7 %. The digital DNA-DNA hybridization values between strain MT5T and the two type strains, P. pachastrellae and P. aestusnigri, were 38.9±2.5 and 25.8±2.4 %, respectively. The average nucleotide identity values between strain MT5T and the two type strains were 90.3 and 87.0 %, respectively. Strain MT5T and the two type strains shared 94.98 and 86.2 % average amino acid identity, and 30 and 33 Karlin genomic signature, respectively. The sole respiratory menaquinone was Q-9. The major polar lipids were phosphatidylethanolamine, diphosphatidyglycerol and phosphatidylglycerol. The predominant cellular fatty acids of strain MT5T were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) (35.3 %), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) (24.1 %), C16 : 0 (15.9 %) and C12 : 0 (7.2 %). The G+C content of the genomic DNA was 61.2 mol%. The combined genotypic and phenotypic data indicated that strain MT5T represents a novel species of the genus Pseudomonas, for which the name Pseudomonas abyssi sp. nov. is proposed, with the type strain MT5T (=KCTC 62295T=MCCC 1K03351T).