47 research outputs found

    <i>Sneathiella chinensis</i> gen. nov., sp. nov., a novel marine alphaproteobacterium isolated from coastal sediment in Qingdao, China

    Get PDF
    The taxonomic position of strain LMG 23452T, which was isolated from coastal sediment from an aquaculture site near Qingdao, China, in 2000, was determined. Strain LMG 23452T comprised Gram-negative, non-spore-forming, motile rods and was found to be a halotolerant, aerobic, chemoheterotroph that produces catalase and oxidase. Comparative 16S rRNA gene sequence analysis revealed that strain LMG 23452T shared approximately 89 % sequence similarity with members of the genera Devosia, Hyphomonas, Ensifer and Chelatococcus, which belong to two different orders within the Alphaproteobacteria. Further phylogenetic analysis of the 16S rRNA gene sequence showed that strain LMG 23452T formed a separate branch within the order Rhizobiales, falling between the genera Devosia and Ensifer of the families Hyphomicrobiaceae and Rhizobiaceae, respectively. Strain LMG 23452T could be differentiated from its closest phylogenetic neighbours on the basis of several phenotypic features, including hydrolysis of the substrates starch and casein and assimilation of the carbohydrates d-glucose, d-mannose, mannitol, maltose and l-arabinose, and chemotaxonomically by the presence of the fatty acids C14 : 0 3-OH, C16 : 1ω11c, C16 : 1 ω5c and C18 : 1ω5c. The major fatty acids detected in strain LMG 23452T were C18 : 1 ω7c, C16 : 0, C19 : 0 cyclo ω8c, C16 : 1 ω7c and C17 : 1ω6c and the G+C content of the genomic DNA was 57.1 mol%. Therefore, the polyphasic data support the placement of strain LMG 23452T within a novel genus and species, for which the name Sneathiella chinensis gen. nov., sp. nov. is proposed. The type strain is LMG 23452T (=CBMAI 737T)

    Prospects of negative triangularity tokamak for advanced steady-state confinement of fusion plasmas in MHD stability consideration

    Full text link
    The steady-state confinement, beta limit, and divertor heat load are among the most concerned issues for toroidal confinement of fusion plasmas. In this work, we show that the negative triangularity tokamak has promising prospects to address these issues. We first demonstrate that the negative triangularity tokamak generates the filed line rotation transform more effectively. This brings bright prospects for the advanced steady-state tokamak scenario. Given this, the MHD stability and equilibrium confinement of negative triangularity tokamak are investigated. We point out that the negative triangularity configuration with a broad pressure profile is indeed more unstable for low-n magnetohydrodynamic modes than the positive triangularity case so that the H-mode confinement can hardly be achieved in this configuration, where n is the toroidal mode number. Nevertheless, we found that the negative triangularity configuration with high bootstrap current fraction, high poloidal beta, and peaked pressure profiles can achieve higher normalized beta for low-n modes than the positive triangularity case. In a certain parameter domain, the normalized beta can reach about twice the extended Troyon limit, while the same computation indicates that the positive triangularity configuration is indeed constrained by the Troyon limit. This shows that the negative triangularity tokamaks are not only favorable for divertor design to avoid the edge localized modes but also can have promising prospects for advanced steady-state confinement of fusion plasmas in high beta
    corecore