A chromosome-scale reference genome of Aquilegia oxysepala var.kansuensis

The genus Aquilegia(Ranunculaceae)has been cultivated as ornamental and medicinal plants for centuries.With petal spurs of strikingly diverse size and shape,Aquilegia has also been recognized as an excellent system for evolutionary studies.Pollinator‐mediated selection for longer spurs is believed to have shaped the evolution of this genus,especially the North American taxa.Recently,however,an opposite evolutionary trend was reported in an Asian lineage,where multiple origins of mini-or even nonspurred morphs have occurred.Interesting as it is,the lack of genomic resources has limited our ability to decipher the molecular and evolutionary mechanisms underlying spur reduction in this special lineage.Using long-read sequencing(PacBio Sequel),in combination with optical maps(BioNano DLS)and Hi–C,we assembled a high-quality reference genome of A.oxysepala var.kansuensis,a sister species to the nonspurred taxon.The final assembly is approximately 293.2 Mb,94.6%(277.4 Mb)of which has been anchored to 7 pseudochromosomes.A total of 25,571 protein-coding genes were predicted,with 97.2%being functionally annotated.When comparing this genome with that of A.coerulea,we detected a large rearrangement between Chr1 and Chr4,which might have caused the Chr4 of A.oxysepala var.kansuensis to partly deviate from the“decaying”path that was taken before the split of Aquilegia and Semiaquilegia.This high-quality reference genome is fundamental to further investigations on the development and evolution of petal spurs and provides a strong foundation for the breeding of new horticultural Aquilegia cultivars.

Silicon lithium-ion battery anode with enhanced performance： Multiple effects of silver nanoparticles

Silicon has been regarded as one of the most promising next generation lithium-ion battery anode. How- ever, the poor cyclic stability of the Si based anode has severely limited its practical applications, which is even worse with high mass loading density （〉1 mg cm^-2 ）. A new concept has been developed to enhance the electrochemical performance of the Si nanoparticle anode. Silver nanoparticles are composited with the silicon nanoparticles in a facile way for the first time. It is found that the mechanical properties of the Si electrode have been significantly improved by the incorporation of the silver nanoparticles, leading to enhanced cyclic performance. With the Si/Ag mass ratio of 4：1, the reversible specific discharge capacity is retained as l 156 mA h g^-1 after 100 cycles at 200 mAg^-1, which is more than three times higher than that of the bare silicon （318 mA h g^-1 ）. The rate performance has been effectively improved as well due to excellent electron conductivity of the silver nanoparticles.

Role of nitric oxide in the genotoxic response to chronic microcystin-LR exposure in human–hamster hybrid cells

Microcystin-LR （MC-LR） is the most abundant and toxic microcystin congener and has been classified as a potential human carcinogen （Group 2B） by the International Agency for Research on Cancer. However, the mechanisms underlying the genotoxic effects of MC-LR during chronic exposure are still poorly understood. In the present study, human-hamster hybrid （AL） cells were exposed to MC-LR for varying lengths of time to investigate the role of nitrogen radicals in MC-LR-induced genotoxicity. The mutagenic potential at the CD59 locus was more than 2-fold higher （p 〈 0.01） in AL ceUs exposed to a cytotoxic concentration （1 μmol/L） of MC-LR for 30 days than in untreated control ceils, which was consistent with the formation of micronucleus. MC-LR caused a dose-dependent increase in nitric oxide （NO） production in treated cells. Moreover, this was blocked by concurrent treatment with the NO synthase inhibitor NC-methyl-L-arginine （L-NMMA）, which suppressed MC-LR- induced mutations as well. The survival of mitochondrial DNA-depleted （pO） AL ceils was markedly decreased by MC-LR treatment compared to that in AL cells, while the CD59 mutant fraction was unaltered. These results provided clear evidence that the genotoxicity associated with chronic MC-LR exposure in mammalian cells was mediated by NO and might be considered as a basis for the development of therapeutics that prevent carcinogenesis.

Aging-independent and size-dependent genotoxic response induced by titanium dioxide nanoparticles in mammalian cells

Titanium dioxide nanoparticles (TiO2 NPs) are subjected to various transformation processes (chemical,physical and biological processes) in the environment,potentially affecting their bioavailability and toxic properties.However,the size variation of TiO2 NPs during aging process and subsequent effects in mammalian cells are largely unknown.The aim of this study was to illustrate the adverse effects of TiO2 NPs in different sizes (5,15 and <100 nm) during aging process on human-hamster hybrid (AL) cells.There was an aging-time dependent enhancement of average hydrodynamic size in TiO2 NPs stock suspensions.The cytotoxicity of fresh TiO2 NPs increased in a size-dependent manner;in contrast,their genotoxicity decreased with the increasing sizes of NPs.No significant toxicity difference was observed in cells exposed to either fresh or 60 day-aged TiO2 NPs.Both Fresh and aged TiO2 NPs efficiently induced mitochondrial dysfunction and activated Caspase-3/7 in a size-dependent manner.Using mitochondrial-DNA deficient (ρ°) AL cells,we further discovered that mitochondrial dysfunction made significant contribution to the size-dependent toxicity induced by TiO2 NPs during the aging process.Taken together,our data indicated that TiO2 NPs could significantly induced the cytotoxicity and genotoxicity in an aging time-independent and size-dependent manner,which were triggered by mitochondrial dysfunction.Our study suggested the necessity to include size as an additional parameter for the cautious monitoring of TiO2 NPs disposal before entering the environment.

THE TIME INTERVAL ALIGNMENT (IA) POLICIES, BOUNDARY AND APPLICATIONS WITH MULTIPLE STREAM ARRIVALS

This paper discusses a class of interval alignment （IA） scheduling policies, which are particularly effective for the systems that do not have Markovian structure. The numerical results show that IA policies effectively smooth part flows, improve performance and decrease average Work-in-Process （WlP） by adding intermediate delays to the system, The boundary of IA policy is proven and the applications of IA policy in the system with multiple stream arrivals have been discussed. With the combination of release policy, it is practical to implement IA to multiple stream arrival system.