Progress in Developing High Energy Nozzle Beams

Electron beam studies of skimmer phenomena and effect on high energy nozzle beam formatio

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

On Vague Computers

Vagueness is something everyone is familiar with. In fact, most people think that vagueness is closely related to language and exists only there. However, vagueness is a property of the physical world. Quantum computers harness superposition and entanglement to perform their computational tasks. Both superposition and entanglement are vague processes. Thus quantum computers, which process exact data without "exploiting" vagueness, are actually vague computers

Statistical Theory of Parity Nonconservation in Compound Nuclei

We present the first application of statistical spectroscopy to study the root-mean-square value of the parity nonconserving (PNC) interaction matrix element M determined experimentally by scattering longitudinally polarized neutrons from compound nuclei. Our effective PNC interaction consists of a standard two-body meson-exchange piece and a doorway term to account for spin-flip excitations. Strength functions are calculated using realistic single-particle energies and a residual strong interaction adjusted to fit the experimental density of states for the targets, ^{238} U for A\sim 230 and ^{104,105,106,108} Pd for A\sim 100. Using the standard Desplanques, Donoghue, and Holstein estimates of the weak PNC meson-nucleon coupling constants, we find that M is about a factor of 3 smaller than the experimental value for ^{238} U and about a factor of 1.7 smaller for Pd. The significance of this result for refining the empirical determination of the weak coupling constants is discussed.Comment: Latex file, no Fig

Gamma-ray bursts and X-ray melting of material as a potential source of chondrules and planets

The intense radiation from a gamma-ray burst (GRB) is shown to be capable of melting stony material at distances up to 300 light years which subsequently cool to form chondrules. These conditions were created in the laboratory for the first time when millimeter sized pellets were placed in a vacuum chamber in the white synchrotron beam at the European Synchrotron Radiation Facility (ESRF). The pellets were rapidly heated in the X-ray and gamma-ray furnace to above 1400 C melted and cooled. This process heats from the inside unlike normal furnaces. The melted spherical samples were examined with a range of techniques and found to have microstructural properties similar to the chondrules that come from meteorites. This experiment demonstrates that GRBs can melt precursor material to form chondrules that may subsequently influence the formation of planets. This work extends the field of laboratory astrophysics to include high power synchrotron sources.Comment: 8 pages, 10 figures. Proceedings of the 5th INTEGRAL Workshop, Munich 16-20 February 2004. High resolution figures available at http://bermuda.ucd.ie/%7Esmcbreen/papers/duggan_01.pd

No-Till: North Dakota Research Emphasis

Introduction of no-till into North Dakota soil management systems has raised many questions relative to performance under present cropping or climatic conditions. A number of long term cooperative research projects were established in 1977 to answer these questions and set some guidelines for no-till production systems. The areas of research emphasis at various experiment stations are discussed along with preliminary results on one year's data

The Diagnostic Value of Pain

Based on an Address delivered to the Royal Medical Society on Friday, 12th January 1960.Pain is usually the main lead, and often the only clue to diagnosis. For example angina of effort may be associated with a normal ECG at rest, while an ECG may frequently show evidence of myocardial ischaemia in patients who do not suffer from angina pectoris. The clinical history and the response to a controlled clinical trial may make the diagnosis certain, yet mistakes will be made, patients lives altered and their outlook upon the future warped, unless a careful analysis of the various aspects of pain is the rule. This analysis must be made exactly and without the bias of preconceived ideas

Estimating the nuclear level density with the Monte Carlo shell model

A method for making realistic estimates of the density of levels in even-even nuclei is presented making use of the Monte Carlo shell model (MCSM). The procedure follows three basic steps: (1) computation of the thermal energy with the MCSM, (2) evaluation of the partition function by integrating the thermal energy, and (3) evaluating the level density by performing the inverse Laplace transform of the partition function using Maximum Entropy reconstruction techniques. It is found that results obtained with schematic interactions, which do not have a sign problem in the MCSM, compare well with realistic shell-model interactions provided an important isospin dependence is accounted for.Comment: 14 pages, 3 postscript figures. Latex with RevTex. Submitted as a rapid communication to Phys. Rev.

Corynebacterium kroppenstedtii subsp. demodicis is the endobacterium of Demodex folliculorum

Background Demodex spp. mites are the most complex member of the human skin microbiome. Mostly they are commensals, although their pathophysiological role in inflammatory dermatoses is recognized. Demodex mites cannot be cultivated in vitro , so only little is known about their life cycle, biology and physiology. Different bacterial species have been suggested to be the endobacterium of Demodex mites, including Bacillus oleronius , B. simplex , B. cereus and B. pumilus . Objectives Our aim was to find the true endobacterium of human Demodex mites. Methods The distinct genetic and phenotypic differences and similarities between the type strain and native isolates are described by DNA sequencing, PCR , MALDI ‐TOF , DNA ‐DNA hybridization, fatty and mycolic acid analyses, and antibiotic resistance testing. Results We report the true endobacterium of Demodex folliculorum , independent of the sampling source of mites or life stage: Corynebacterium kroppenstedtii subsp. demodicis . Conclusions We anticipate our finding to be a starting point for more in‐depth understanding of the tripartite microbe–host interaction between Demodex mites, its bacterial endosymbiont and the human host