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A tail bubble is generated behind a high-speed vehicle at the early stage of the underwater launch process. The tail bubble dynamic behavior involves expansion, overexpansion, contraction, pinch-off and jet formation, and it significantly influences the vehicle's movement. However, the tail bubble dynamic behavior is an issue not very well studied. This paper establishes a numerical model for the interaction between the tail bubble and the vehicle based on the boundary element method (BEM) to gain new insight into this issue. The BEM results are compared to a computational fluid dynamics model to validate the numerical model, and good agreement is achieved. Additionally, a convergence test of the BEM model is conducted to verify its independence of the mesh size. The influence of some governing parameters on the evolution of the tail bubble is then systematically studied, focusing on its maximum radius, pinch-off time, and pinch-off position. There are two pinch-off position regimes of the tail bubble, one at the bottom and the other near the middle. [ABSTRACT FROM AUTHOR]

A Gram-negative, facultatively anaerobic, non-motile, nonspore- forming, coccoid or rod-shaped and creamy-pigmented bacterium, designated SYP-B2100T, was isolated from the rhizospheric soil of Codonopsis clematidea in the Xinjiang Uygur Autonomous Region, China. The optimal growth occurred at 28°C, pH 5.0, in the absence of NaCl. The cells tested positive in catalase and methyl red tests but negative in oxidase, urease, gelatinase, milk coagulation, and peptonisation, H2S production, nitrate reduction, and Voges-Proskauer tests. The major isoprenoid quinone was ubiquinone-8 (Q-8). The major cellular fatty acids were C16:0 and summed feature 8. The polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, and phosphatidylglycerol. The 16S rRNA gene sequence of strain SYP-B2100T was the most similar to that of Rahnella inusitata DSM 30078T (96.9%) within the family Enterobacteriaceae. The genomic DNA G + C content of strain SYP-B2100T was 50.3 mol%. The combined data from the phylogenetic, morphological, physiological, biochemical, and chemotaxonomic analyses presented in this study support the conclusion that strain SYP-B2100T represents a novel species of a new genus, for which the name Edaphovirga cremea gen. nov., sp. nov. is proposed; the type strain is SYPB2100T (= CGMCC 1.5857T = DSM 105170T = KCTC 62024T). [ABSTRACT FROM AUTHOR]

Reuse of secondary municipal effluent from wastewater treatment plants in water bodies could effectively alleviate freshwater resource shortage. However, excessive nutrients must be efficiently removed to prevent eutrophication. Compared with other means of advanced wastewater treatment, microalgae-based processes display overwhelming advantages including efficient and simultaneous N and P removal, no requirement of additional chemicals, O generation, CO mitigation, and potential value-added products from harvested biomass. One particular challenge of microalgae-based advanced municipal wastewater treatment compared to treatment of other types of wastewater is that concentrations of nutrients and N:P ratios in secondary municipal effluent are much lower and imbalanced. Therefore, there should be comprehensive considerations on nutrient removal from this specific type of effluent. Removal of nutrients and organic substances, and other environmental benefits of microalgae-based advanced municipal wastewater treatment systems were summarized. Among the existing studies on microalgal advanced nutrient removal, much information on major parameters is absent, rendering performances between studies not really comparable. Mechanisms of microalgae-based nitrogen and phosphorus removal were respectively analyzed to better understand advanced nutrient removal from municipal secondary effluent. Factors influencing microalgae-based nutrient removal were divided into intrinsic, environmental, and operational categories; several factors were identified in each category, and their influences on microalgal nutrient removal were discussed. A multiplicative kinetic model was integrated to estimate microalgal growth-related nutrient removal based majorly on environmental and intrinsic factors. Limitations and prospects of future full-scale microalgae-based advanced municipal wastewater treatment were also suggested. The manuscript could offer much valuable information for future studies on microalgae-based advanced wastewater treatment and water reuse. [ABSTRACT FROM AUTHOR]

Two novel bacterial strains, designated SYP-B540 and SYP-B556, were isolated from rhizospheric soil of Panax notoginseng located at Yunnan Province, China. Both strains were Gram-staining negative, aerobic, non-motile, elongated rod shaped and yellow coloured. They grew optimally at 28 °C and pH 7.0. Analysis of 16S rRNA gene sequences showed that the two strains shared 99.8 % sequence similarity to each other, but lower than 97.6 % to the other known species of the genus Flavobacterium. The predominant respiratory quinone for the two strains was MK-6, and the major fatty acids were iso-C and summed Feature 3 (comprising 16:1 ω7c and/or 16:1 ω6c). The polar lipids consisted of phosphatidylethanolamine, two unidentified polar lipids and three unidentified amino-phospholipids. The DNA G+C contents of strains SYP-B540 and SYP-B556 were 33.3 and 32.7 mol%, respectively. In addition, the DNA-DNA hybridization values of strains SYP-B540 and SYP-B556 to their closest phylogenetic neighbors were significantly lower than 70 %. On the basis of the polyphasic taxonomy studies, strains SYP-B540 and SYP-B556 represent a novel species of the genus Flavobacterium, for which the name Flavobacterium notoginsengisoli sp. nov. is proposed. The type strain is SYP-B540 (=KCTC 32505 = NBRC 110012 = BCRC 80724). [ABSTRACT FROM AUTHOR]

A Gram-positive, aerobic, non-motile and pale yellow colour actinobacterial strain, designated SYP-B575, was isolated from rhizosphere soil of Panax notoginseng. The optimal growth of the strain was found to occur at 28 °C, pH 7.0 and without NaCl. Phylogenetic analysis indicated that strain SYP-B575 clearly belongs to the genus Sinomonas and should be considered as a candidate of novel species within this genus. The 16S rRNA gene sequence similarities between strain SYP-B575 and the other Sinomonas type strains ranged from 97.3 to 96.0 %. The predominant isoprenoid quinone was identified as MK-9(H) and the major fatty acids were identified as anteiso-C and anteiso-C. The polar lipids were found to consist of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol and glycolipids. The major cell-wall amino acids were identified as Lys, Ala, Glu, Gly and Ser. The whole-cell sugars were identified as mannose, ribose, rhamnose, glucose and galactose. The G+C content of the genomic DNA was determined to be 66.6 mol%. The DNA-DNA relatedness values between SYP-B575 and its closest phylogenetic neighbours were lower than 35.5 %. On the basis of this polyphasic taxonomic study, strain SYP-B575 represents a novel species of the genus Sinomonas, for which the name Sinomonas notoginsengisoli sp. nov. is proposed. The type strain is SYP-B575 (=DSM 27685 = KCTC 29237). [ABSTRACT FROM AUTHOR]

A lot of slow fluctuations of water level have been observed in the original recording maps of subsurface fluid in Well Shuozhou, Shanxi Province. Some typical recording maps of the “precursors” are introduced in the paper and the features of the “precursors” recorded by the well are analyzed. The results show that 38% strong earthquakes possess this kind of record, which has a fluctuation period arranging from several to tens of minutes and appear mostly two days before the earthquakes. Moreover, the mechanism, transmission and responding conditions of well water level are discussed, as well as the scientific meaning and practical value of the “precursor” of the well water level in earthquake predictions. [ABSTRACT FROM AUTHOR]

Ketogulonicigenium vulgare has been widely used in vitamin C two-step fermentation. Four K. vulgare strains (WSH-001, Y25, Hbe602 and SKV) have been completely genome-sequenced, however, less attention was paid to elucidate the reason for the differences in 2-KGA yield on genetic level. Here, a novel K. vulgare SPU B805 with higher 2-keto-L-gulonic acid (2-KGA) yield, was genome-sequenced to confirm harboring one circular chromosome with plasmid free. Comparative genome analyses showed that the absence of plasmid 2 was an important factor for its high 2-KGA productivity. The amino acid biosynthetic pathways in strain SPU B805 are much more complete than those in other K. vulgare strains. Meanwhile, strain SPU B805 harbored a complete PPP and TCA route, as well as a disabled EMP and ED pathway, same as to strain SKV, whereas strain WSH-001, Y25 and Hbe602 harbored complete PPP, ED, TCA pathway and a nonfunctional EMP pathway. The transcriptome of strain SPU B805 validated the carbon metabolism in cytoplasm mainly through the PPP pathway due to its higher transcriptional levels. This is the first time to elucidate the underlying mechanism for the difference in 2-KGA yield, and it is of great significance for strain improvement in the industrial fermentation. [ABSTRACT FROM AUTHOR]