Methionine has an almost unique stimulatory effect on biosynthesis of cephalosporins (by Cephalosporium acremonium). No other sulfur-containing compound tested, except dl-methionine-dl-sulfoxide, replaced methionine. dl-Methionine stimulated the synthesis of cephalosporins when added after the growth phase. The utilization of inorganic sulfate was repressed by methionine. Experiments with l-met...

Lithium/sulfur (Li/S) cells are receiving significant attention as an alternative power source for zero-emission vehicles and advanced electronic devices due to the very high theoretical specific capacity (1675 mA·h/g) of the sulfur cathode. However, the poor cycle life and rate capability have remained a grand challenge, preventing the practical application of this attractive technology. Here,...

Pyruvate formate-lyase activating enzyme utilizes an iron-sulfur cluster and S-adenosylmethionine to generate the catalytically essential glycyl radical on pyruvate formate-lyase. Variable-temperature (4.2200 K) and variable-field (0.05-8 T) Mössbauer spectroscopy has been used to characterize the iron-sulfur clusters present in anaerobically isolated pyruvate formate-lyase activating enzyme an...

Tremendous effort has been put into developing viable lithium sulfur batteries, due to their high specific energy and relatively low cost. Despite recent progress in addressing the various problems of sulfur cathodes, lithium sulfur batteries still exhibit significant capacity decay over cycling. Herein, we identify a new capacity fading mechanism of the sulfur cathodes, relating to Li(x)S deta...

I t has been observed that rat kidney cortical tissue in ~tro may show an accumulative process with respect to S 3~ when radiosulfate ion is present in the incubation medium (1). Since little is known about this process, experiments described in the present report were undertaken to characterize it further. Whether S 85 uptake by kidney tissue in ~tro should prove to reflect a more or less spec...

An efficient, industry-accepted spray drying method was used to synthesize micro-spherical sulfur/graphene oxide (S/GO) composites as cathode materials within lithium sulfur batteries. The as-designed wrapping of the sulfur-nanoparticles, with wrinkled GO composites, was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The unique morphological desi...

Elemental sulfur exists as a variety of forms in natural systems, from dissolved forms (noted as S8 (aq.)) to bulk elemental sulfur most stable as α-S8 (bulk) (but existing in at least 180 different allotropes and polymorphs). Elemental sulfur can form via a number of biotic and abiotic processes, many of which begin with S-S bonding of practically unlimited length, forming chains and rings of ...

Sulfur is an attractive cathode material with a high specific capacity of 1675 mA h g , but its rapid capacity decay due to polysulfide dissociation presents a significant technical challenge. Here, we present the fabrication of a TiO2/S composite cathode by encapsulating elemental sulfur into TiO2 nanotube hosts for high performance lithium–sulfur batteries. A high capacity of 913 mA h g 1 has...

Owing to the conversion chemistry of the sulfur cathode, the lithium-sulfur (Li-S) batteries exhibit high theoretical energy density. However, the intrinsic mobile redox centers during the sulfur/Li2S-to-lithium polysulfides solid-to-liquid phase transition induce low sulfur utilization and poor cycling life. Herein, the Janus separator of mesoporous cellular graphene framework (CGF)/polypropyl...

Iron-Sulfur (Fe-S) clusters and proteins are essential to many growth and developmental processes. In plants, they exist in the plastids, mitochondria, cytosol, and nucleus. Six types of Fe-S clusters are found in the plastid: classic 2Fe-2S, NEET-type 2Fe-2S, Rieske-type 2Fe-2S, 3Fe-4S, 4Fe-4S, and siroheme 4Fe-4S. Classic, NEET-type, and Rieske-type 2Fe-2S clusters have the same 2Fe-2S core; ...