Treesearch

The synthesis of hydroxylated and O- or N-dealkylated human drug metabolites (HDMs) via selective monooxygenation remains a challenging task for synthetic organic chemists. Here we report that aromatic peroxygenases (APOs; EC 1.11.2.1) secreted by the agaric fungi Agrocybe aegerita and Coprinellus radians catalyzed the H2O2-dependent selective monooxygenation of diverse drugs, including acetanilide, dextrorphan, ibuprofen, naproxen, phenacetin, sildenafil and tolbutamide. Reactions included the hydroxylation of aromatic rings and aliphatic side chains, as well as O- and N-dealkylations and...

A research program has been initiated to formulate new strategies for efficient low-cost lignocellulosic biomass processing technologies for the production of biofuels. This article reviews results from initial research into lignocellulosic biomass structure, recalcitrance, and pretreatment. In addition to contributing towards a comprehensive understanding of lignocellulosic biomass, this work has contributed towards demonstrated optimizations of existing pretreatment methods, and the emergence of new possible pretreatment strategies that remain to be fully developed.

Understanding structure-property relationships for wood cell walls has been hindered by the complex polymeric structures comprising these cell walls and the difficulty in assessing meaningful mechanical property measurements of individual cell walls. To help overcome these hindrances, we have developed two experimental methods: 1) two-dimensional solution state nuclear magnetic resonance (2D NMR) spectroscopy for chemical analysis of near-native state wood polymers, and 2) broadband nanoindentation spectroscopy (BNS) to more accurately assess mechanical properties of individual wood cell...

DNA contains the coding information for the entire set of proteins produced by an organism. The specific combination of proteins synthesized varies with developmental, metabolic and environmental circumstances. This variation is generated by regulatory mechanisms that direct the production of messenger ribonucleic acid (mRNA) and subsequent translation of the nucleotide sequence into amino acid sequences, among other fundamental processes including post-translational modifications. A major step of gene expression regulation is the control of transcription initiation by RNA polymerase II....

Torrefaction is a thermo-chemical conversion process improving the handling, storage and combustion properties of wood. To save storage space and transportation costs, it can be compressed into fuel pellets of high physical and energetic density. The resulting pellets are relatively resistant to moisture uptake, microbiological decay and easy to comminute into small particles. The present study focused on the pelletizing properties of spruce torrefied at 250, 275 and 300 °C. The changes in composition were characterized by infrared spectroscopy and chemical analysis. The pelletizing...

Forest improvement harvests using individual-tree and group selection were conducted in four oak or oak-hickory stands in the Missouri Ozarks with conventional equipment (chainsaw and skidder). Volumes (and revenues) for different timber classes (sawlogs and smallwood from topwood and small trees) and hours of machine use were recorded to calculate production rates. Multiplying these by estimated hourly machine costs and adding loading and transportation costs plus stumpage yielded harvest plus delivery costs. Loggers kept machine costs low by operating old equipment with low capital costs...

Cellulosic webs, such as paper materials, are composed of an interwoven, bonded network of cellulose fibers. Strength-controlling parameters in these webs are influenced by constituent fibers and method of processing and manufacture. Instead of estimating the effect on tensile strength of each processing/manufacturing variable, this study modifies and compares the point stress criteria and average stress criteria models used to estimate defect-free (i.e., maximum possible) tensile strength and the inherent size of the cumulative effect of strength-limiting defects. The two major modificatio...

Quantifying uncertainty in measured properties of nanomaterials is a prerequisite for the manufacture of reliable nanoengineered materials and products. Yet, rigorous uncertainty quantification (UQ) is rarely applied for material property measurements with the atomic force microscope (AFM), a widely used instrument that can measure properties at nanometer scale resolution of both inorganic and biological surfaces and nanomaterials. We present a framework to ascribe uncertainty to local nanomechanical properties of any nanoparticle or surface measured with the AFM by taking into account the...

The concept of sustainable harvests is not new to lumber and paper companies—they have been concerned about it and been practicing it for decades, long before it became the headline in a newspaper article. After decades of static products and markets, the industry is offered an opportunity to add products in a new business sector—fuels and chemicals. Although paper companies have a long association with the naval stores chemical business, this new market will see larger volumes and more numerous product opportunities. As with all new markets, this will create turbulence and there will be...

Although preservative-treated wood is a durable construction material, it is eventually removed from service. The typical fate of treated wood removed from service varies depending on the original application and the type of preservative used. Currently, most treated wood removed from service in the United States is placed in landfills (Clausen 2003). Treated wood is not listed as a hazardous waste under federal law, and it can be disposed of in any waste management facility authorized under state and local law to manage such material. There is no doubt that as volumes of waste increase...