Environmental Molecular Sciences Laboratory

About: Environmental Molecular Sciences Laboratory is a facility organization based out in Richland, Washington, United States. It is known for research contribution in the topics: Mass spectrometry & Ion. The organization has 1471 authors who have published 3010 publications receiving 169961 citations.

Template free synthesis of LiV3O8 nanorods as a cathode material for high-rate secondary lithium batteries

Abstract: A novel, template-free, low-temperature method has been developed to synthesize LiV3O8 cathode material for high-power secondary lithium (Li) batteries. The LiV3O8 prepared using this new method was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The thermal decomposition process was investigated using thermogravimetric (TG) and differential thermal analysis (DTA). LiV3O8 produced using the conventional high-temperature fabrication method also was analyzed. The electrochemical performances and the effects of synthesis temperature on our LiV3O8 and the conventionally produced LiV3O8 were compared. The LiV3O8 produced using our new method has a nanorod crystallite structure composed of uniform, well-separated particles with diameters ranging from 30 to 150 nm. The TEM work reveals the stacking defaults within the nanorod structures, which would facilitate the electron transportation during the insertion and removal process of lithium ions. It delivers specific discharge capacities of 320 mAh g−1 and 239 mAh g−1 at current densities of 100 mA g−1 and 1 A g−1, respectively. It also exhibits excellent capacity retention with only 0.23% capacity fading per cycle. This excellent electrochemical performance can be attributed to the superior structural characteristics of our material, and the results of our study demonstrate that LiV3O8 nanorod crystallites produced by this new thermal decomposition method are promising cathode materials for high-power Li batteries.

Phage-specific metabolic reprogramming of virocells.

Abstract: Ocean viruses are abundant and infect 20-40% of surface microbes. Infected cells, termed virocells, are thus a predominant microbial state. Yet, virocells and their ecosystem impacts are understudied, thus precluding their incorporation into ecosystem models. Here we investigated how unrelated bacterial viruses (phages) reprogram one host into contrasting virocells with different potential ecosystem footprints. We independently infected the marine Pseudoalteromonas bacterium with siphovirus PSA-HS2 and podovirus PSA-HP1. Time-resolved multi-omics unveiled drastically different metabolic reprogramming and resource requirements by each virocell, which were related to phage-host genomic complementarity and viral fitness. Namely, HS2 was more complementary to the host in nucleotides and amino acids, and fitter during infection than HP1. Functionally, HS2 virocells hardly differed from uninfected cells, with minimal host metabolism impacts. HS2 virocells repressed energy-consuming metabolisms, including motility and translation. Contrastingly, HP1 virocells substantially differed from uninfected cells. They repressed host transcription, responded to infection continuously, and drastically reprogrammed resource acquisition, central carbon and energy metabolisms. Ecologically, this work suggests that one cell, infected versus uninfected, can have immensely different metabolisms that affect the ecosystem differently. Finally, we relate phage-host genome complementarity, virocell metabolic reprogramming, and viral fitness in a conceptual model to guide incorporating viruses into ecosystem models.

A Theoretical Study of the Structures of Flavin in Different Oxidation and Protonation States

Abstract: Ab initio molecular orbital theory was used to investigate the structure of flavin in different oxidation and protonation states using lumiflavin as a model compound. According to our study, oxidized flavin is planar no matter what its protonation state or whether it participates in hydrogen bonding. The structures of flavin semiquinone radicals are planar or very close to planar, but the reduced flavin H3Flred (9) is bent with a ring puckering angle of 27.3° along the N5 and N10 axis. The calculations indicate that N1 is the site of protonation for oxidized flavin, which is in agreement with several crystallographic studies. The calculated spin density distribution for flavin semiquinone radicals is also consistent with experimental results. Electrostatic potential derived charges at the RHF/6-31G* level of theory are also provided for both oxidized and reduced flavins.