Investigation of nickel supported catalysts for the upgrading of brown peat derived gasification products

A gasification test rig was designed in which peat was gasified under nitrogen over a temperature range 25-550 degrees C at 5 degrees C min(-1). The gasification unit resulted in 35.5 wt% of the carbon present in the peat being converted to a volatile fraction. The volatile fraction was transferred to a secondary catalytic reforming reactor at 800 degrees C. The thermal effect of the second reactor resulted in an increase in the CO, CO2 and CH4 content of the volatile fraction, a syngas ratio of 0.75 and a higher heating value (HHV) of 26.5 MJ kg(-1). Several nickel-supported catalysts were investigated with the intention that they should give an increase in the conversion of the condensable hydrocarbons in the volatile fraction to CO, CO2 and CH4, and a resultant gas stream suitable for use in an integrated gasification combined cycle plant (IGCC) (i.e. syngas ratio 2:1, low methane content and better HHV). Alumina-supported nickel catalysts investigated gave the highest activities and co-precipitated Ni/Al catalysts were most active. A Ni/Al 3:17 catalyst increased the conversion of the hydrocarbons to 91.5%, gave a syngas ratio of 1.81:1, increased the HHV by a factor of 5.3 and completely eliminated methane from the gas stream.     

Molecular mechanisms underlying a unique intermediate phase of memory in aplysia

Short- and long-term synaptic facilitation induced by serotonin at Aplysia sensory-motor (SN-MN) synapses has been widely used as a cellular model of short- and long-term memory for sensitization. In recent years, a distinct intermediate phase of synaptic facilitation (ITF) has been described at SN-MN synapses. Here, we identify a novel intermediate phase of behavioral memory (ITM) for sensitization in Aplysia and demonstrate that it shares the temporal and mechanistic features of ITF in the intact CNS: (1) it declines completely prior to the onset of LTM, (2) its induction requires protein but not RNA synthesis, and (3) its expression requires the persistent activation of protein kinase A. Thus, in Aplysia, the same temporal and molecular characteristics that distinguish ITF from other phases of synaptic plasticity distinguish ITM from other phases of behavioral memory.     

Sedimentary microbial community dynamics in a regulated stream: East Fork of the Little Miami River,Ohio

A field study was conducted in the Lower East Fork of the Little Miami River, a regulated stream in Clermont county, Ohio, to determine how changes in streamflow, water temperature and photo-period affect sediment microbial community structure. Surface sediment cores were collected from sampling stations spanning 60 river kilometers three to four times per year between October 1996 and October 1999. During the final year of the field study, water temperature, water depth, conductivity, total suspended solids, dissolved organic carbon, instantaneous streamflow velocity, sediment grain size and sediment organic matter were determined. Total microbial biomass was measured using the phospholipid phosphate technique (PLP) and ranged between 2 and 134 nmol PLP * g(-1) dry weight sediment with a mean of 25 nmol PLP * g(-1). Microbial community structure was determined using the phospholipid fatty acid analysis and indicated seasonal shifts in sedimentary microbial community composition. January to June sedimentary microbial biomass was predominately prokaryotic (60% +/- 2), whereas microeukaryotes dominated samples collected during the late summer (55% +/- 2.4) and fall (60% +/- 2). These changes were correlated with stream discharge and water temperature. Microbial community structure varied spatially about a reservoir with prokaryotic biomass dominant at upstream stations and eukaryotic biomass dominant at downstream stations. These findings reveal that sedimentary microbial communities in streams are dynamic responding to the seasonal variation of environmental factors.     

Multigene DNA prime-boost vaccines for SHIV89.6P

We assessed four prime-boost vaccine regimens with a Gene Gun component for SHIV89.6P in Macaca nemestrina. A dosing experiment using beta-galactosidase plasmid showed that 30 or 45 shots per dose elicited higher titer antibody than smaller doses. For SHIV89.6P, we administered a six-plasmid vaccine capable of producing non-infectious virions in vivo in combination with either vaccinia recombinants or inactivated virus. DNA prime/vaccinia boost, or the reverse, elicited strong immune responses. The SHIV89.6P challenge virus was grown in M. nemestrina peripheral blood mononuclear cells and titered in vivo intrarectally. As has been observed for SHIV89.6P in M. mulatta, the infected M. nemestrina experienced rapid and severe loss of circulating CD4+ T cells. Vaccinated macaques were challenged three weeks after the last boost. DNA prime/vaccina boost or vaccina prime/DNA boost protected 11/12 animals from acute CD4+ T cell depletion and disease, while other regimens were not effective.     

Towards a framework for the evolutionary genomics of Kinetoplastids: what kind of data and how much?

The current status of kinetoplastids phylogeny and evolution is discussed in view of the recent progresses on genomics. Some ideas on a potential framework for the evolutionary genomics of kinetoplastids are presented.     

A bacterial genome in flux: the twelve linear and nine circular extrachromosomal DNAs in an infectious isolate of the Lyme disease spirochete Borrelia burgdorferi

We have determined that Borrelia burgdorferi strain B31 MI carries 21 extrachromosomal DNA elements, the largest number known for any bacterium. Among these are 12 linear and nine circular plasmids, whose sequences total 610 694 bp. We report here the nucleotide sequence of three linear and seven circular plasmids (comprising 290 546 bp) in this infectious isolate. This completes the genome sequencing project for this organism; its genome size is 1 521 419 bp (plus about 2000 bp of undetermined telomeric sequences). Analysis of the sequence implies that there has been extensive and sometimes rather recent DNA rearrangement among a number of the linear plasmids. Many of these events appear to have been mediated by recombinational processes that formed duplications. These many regions of similarity are reflected in the fact that most plasmid genes are members of one of the genome's 161 paralogous gene families; 107 of these gene families, which vary in size from two to 41 members, contain at least one plasmid gene. These rearrangements appear to have contributed to a surprisingly large number of apparently non-functional pseudogenes, a very unusual feature for a prokaryotic genome. The presence of these damaged genes suggests that some of the plasmids may be in a period of rapid evolution. The sequence predicts 535 plasmid genes >/=300 bp in length that may be intact and 167 apparently mutationally damaged and/or unexpressed genes (pseudogenes). The large majority, over 90%, of genes on these plasmids have no convincing similarity to genes outside Borrelia, suggesting that they perform specialized functions.     

A new arthropod from the Silurian Konservat-Lagerstätte of Herefordshire, UK

A small, non-biomineralized, macrophagous arthropod with chelicerate affinities, Offacolus kingi gen. et sp. nov., from the Silurian (Wenlock Series) of Herefordshire, UK, is described. The dorsal exoskeleton comprises an arch-like cephalic shield, a thorax of three free tergites and a triangular posterior tagma of five fused tergites, the last with a stout postero-dorsally directed medial spine. Seven pairs of appendages beneath the cephalic shield surround a postero-medially sited oral cavity on the ventral surface of the head. Appendages I and, probably II are uniramous and project antero-ventrally; I was sensory and II sensory and/or ambulatory. Appendages III-VI are biramous, each with an antero-ventrally projecting ramus and a robust, highly geniculate, horizontally oriented ramus that projects through an anterior gape. The former rami were ambulatory and the latter have spinose terminal podomeres and functioned as a unit for trapping food and transferring it towards the oral cavity. Appendage VII, which is probably uniramous, is posteroventrally directed and flap like. Each tergite of the thorax and posterior tagma covers at least a pair (probably two pairs) of probably biramous appendages with each ramus flap like and setose.