Global tropospheric chemistry: Chemical fluexes in the global atmosphere

In October 1987, NSF, NASA, and NOAA jointly sponsored a workshop at Columbia University to assess the experimental tools and analysis procedures in use and under development to measure and understand gas and particle fluxes across this critical air-surface boundary. Results are presented for that workshop. It is published to summarize the present understanding of the various measurement techniques that are available, identify promising new technological developments for improved measurements, and stimulate thinking about this important measurement challenge

Recent Developments in Robocasting of Ceramics and Multimaterial Deposition

Robocasting is a freeform fabrication technique for dense ceramics and composites that is based on layer-wise deposition of highly loaded colloidalslurries. The process is essentially binderless with less than 1% organics and parts can be fabricated, dried, and completely sintered in less than 24 hours. This overview will highlight recent materials developments for structural applications and modelling of slurry flow. Fabrication of preforms for alumina/metal composites will be discussed as well as techniques for multimaterial deposition in both graded structures and discrete placement of fugitive materials.Mechanical Engineerin

The Mr 28,000 gap junction proteins from rat heart and liver are different but related

The sequence of the amino-terminal 32 residues of the rat heart Mr 28,000 gap junction protein presented here allows, for the first time, a sequence comparison of gap junctional proteins from different tissues (heart and liver). Comparison of the rat heart gap junction protein sequence and that available from rat liver reveals 43% sequence identity and conservative changes at an additional 25% of the positions. Both proteins exhibit a hydrophobic domain which could represent a transmembrane span of the junction. This result unequivocally demonstrates the existence of at least two forms of the gap junction protein. As yet, no homology is evident between the gap junctional proteins of either heart or liver and main intrinsic protein from rat eye lens

Maximally Symmetric Spin-Two Bitensors on S3S^3 and H3H^3

The transverse traceless spin-two tensor harmonics on $S^3$ and $H^3$ may be denoted by $T^{(kl)}{}_{ab}$. The index $k$ labels the (degenerate) eigenvalues of the Laplacian $\square$ and $l$ the other indices. We compute the bitensor $\sum_l T^{(kl)}{}_{ab}(x) T^{(kl)}{}_{a'b'}(x')^*$ where $x,x'$ are distinct points on a sphere or hyperboloid of unit radius. These quantities may be used to find the correlation function of a stochastic background of gravitational waves in spatially open or closed Friedman-Robertson-Walker cosmologies.Comment: 12 pages, RevTeX, uuencoded compressed .tex file, minor typos correcte

Cofactor regeneration by a soluble pyridine nucleotide transhydrogenase for biological production of hydromorphone

We have applied the soluble pyridine nucleotide transhydrogenase of Pseudomonas fluorescens to a cell-free system for the regeneration of the nicotinamide cofactors NAD and NADP in the biological production of the important semisynthetic opiate drug hydromorphone. The original recombinant whole-cell system suffered from cofactor depletion resulting from the action of an NADP(+)-dependent morphine dehydrogenase and an NADH-dependent morphinone reductase. By applying a soluble pyridine nucleotide transhydrogenase, which can transfer reducing equivalents between NAD and NADP, we demonstrate with a cell-free system that efficient cofactor cycling in the presence of catalytic amounts of cofactors occurs, resulting in high yields of hydromorphone. The ratio of morphine dehydrogenase, morphinone reductase, and soluble pyridine nucleotide transhydrogenase is critical for diminishing the production of the unwanted by-product dihydromorphine and for optimum hydromorphone yields. Application of the soluble pyridine nucleotide transhydrogenase to the whole-cell system resulted in an improved biocatalyst with an extended lifetime. These results demonstrate the usefulness of the soluble pyridine nucleotide transhydrogenase and its wider application as a tool in metabolic engineering and biocatalysis

Long-range electron transfer in structurally engineered pentaammineruthenium (histidine-62) cytochrome c

In many biological processes, long-range electron transfer (ET) plays a key role. When the three-dimensional structures of proteins are accurately known, use of modified proteins and protein-protein complexes provides an experimental approach to study ET rates between two metal centers. For Ru(His)- modified proteins, the introduction of histidine residues at any desired surface location by site-directed mutagenesis opens the way for systematic investigations of ET pathways

Evaluation of Three Rations on Growth and Reproductive Performance for Replacement Heifers

Nutrition following weaning of replacement heifers affects their performance as cows. Low levels of energy can delay puberty and reduce conception rates. Excessively high levels can decrease milk production and life span. Previous research indicates that gains should be kept to about 220 pounds from weaning to first breeding. This level of gain precludes high concentrate rations, curtailing flexibility and ability to minimize feed costs when concentrates are a cheaper source of energy. Limiting feed intake to supply desired total energy consumption would allow flexibility and use of higher percentage grain when economical. Limit feeding has been studied with finishing cattle regarding its influence on digestibility of feed stuffs. Limit feeding has been used to produce desired gains in heifers but not studied as a possible feeding program for replacement heifers. This study was conducted to determine if the use of rations containing various energy levels with intake limited could be successfully used to raise replacement heifers

The Effect of Growth Promoting Implants on Feedlot Performance by Gelbvieh Bulls

The objective of this research was to determine the effect on feedlot performance of implanting various growth promotants in young bulls. Responses to these various implants by bulls were compared to a control group of bulls to determine the differences in feedlot performance. These comparisons provide information to help determine the most effective methods of bull feeding