Process Simulation and Cost Analysis for Removing Inorganics from Wood Chips Using Combined Mechanical and Chemical Preprocessing

Inorganic species (ash) in biomass feedstocks negatively impact thermochemical and biochemical energy conversion processes. In this work, a process simulation model is developed to model the reduction in ash content of loblolly logging residues using a combination of air classification and dilute-acid leaching. Various scenarios are considered, and it is found that costs associated with discarding high-ash material from air classification are substantial. The costs of material loss can be reduced by chemical leaching the high-ash fraction obtained from air classification. The optimal leaching condition is found to be approximately 0.1 wt% sulfuric acid at 24 °C. In example scenarios, total process costs in the range of $6–9?/dry tons of product are projected that result in a removal of 14, 62, 39, and 88 % of organics, total ash (inorganics), alkaline earth metals and phosphorus (AAEMS + P), and silicon, respectively. Sensitivity analyses indicate that costs associated with loss of organic material during processing (yield losses), brine disposal, and labor have the greatest potential to impact the total processing cost.     

Multiple DNA polymerase activity solubilized from higher plant chromatin

DNA polymerase preparations solubilized from chromatin of unwashed and washed sugar beet storage tissue exhibit multiple activity peaks when separated by DEAE-Sephadex chromatography. Activity peaks isolated from unwashed and washed tissue required Mg²⁺, all four deoxynucleoside triphosphates and added DNA. Activity from peaks isolated from washed tissue was completely sensitive to pancreatic DNase and insensitive to RNase. Enzyme activity was increased in the tissue during the washing period. In addition, there was a drastic change in template specificity from single-stranded primer in unwashed tissue to double-stranded DNA in washed tissue.     

Efficient RNA virus control in Drosophila requires the RNA methyltransferase Dnmt2

Drosophila use small‐interfering RNA mechanisms to limit the amplification of viral genomes. However, it is unclear how small RNA interference components recognize and separate viral from cellular RNA. Dnmt2 enzymes are highly conserved RNA methyltransferases with substrate specificity towards cellular tRNAs. We report here that Dnmt2 is required for efficient innate immune responses in Drosophila. Dnmt2 mutant flies accumulate increasing levels of Drosophila C virus and show activated innate immune responses. Binding of Dnmt2 to DCV RNA suggests that Dnmt2 contributes to virus control directly, possibly by RNA methylation. These observations demonstrate a role for Dnmt2 in antiviral defence.     

Optimization of a series of heterocycles as survival motor neuron gene transcription enhancers

Spinal muscular atrophy (SMA) is a neurodegenerative disorder that results from mutations in the SMN1 gene, leading to survival motor neuron (SMN) protein deficiency. One therapeutic strategy for SMA is to identify compounds that enhance the expression of the SMN2 gene, which normally only is a minor contributor to functional SMN protein production, but which is unaffected in SMA. A recent high-throughput screening campaign identified a 3,4-dihydro-4-phenyl-2(1H)-quinolinone derivative (2) that increases the expression of SMN2 by 2-fold with an EC₅₀?=?8.3?µM. A structure-activity relationship (SAR) study revealed that the array of tolerated substituents, on either the benzo portion of the quinolinone or the 4-phenyl, was very narrow. However, the lactam ring of the quinolinone was more amenable to modifications. For example, the quinazolinone (9a) and the benzoxazepin-2(3H)-one (19) demonstrated improved potency and efficacy for increase in SMN2 expression as compared to 2.     

Spatially-dependent patterns of plant recovery and sediment accretion following multiple disturbances in a Gulf Coast tidal marsh

Wetlands Ecology and Management - Coastal wetlands are projected to experience increases in anthropogenic and climatic disturbances, which may alter plant-sediment feedbacks critical for...