We introduce and investigate the band gap sturcture of the frequency spectrum for classical electromagnetic and acoustic waves in a high contrast two-component periodic medium. The asymptotics with respect to the high contrast is considered. The limit medium is described in terms of appropriate see-adjoint operators and the convergence to the limit is proven. These limit operators give an idea ...

A perfusion chamber is described with which a tissue culture can be irrigated successively with different immersion media. Only 1-2 ml. of medium are required for each change, which can be accomplished within 1 minute. Simplicity of design permits speed and economy in manufacture. Perfusion by suction instead of by positive pressure has eliminated certain drawbacks of previous designs. Mixing e...

From Pseudomonas sp. PS 6.10, when grown in a casamino acid medium, a pyoverdin was isolated whose primary structure could be deduced from its mass spectrometric fragmentation pattern and amino acid analysis. It belongs to the smallest representatives of this group of siderophores comprising only six amino acids in its peptide chain. When grown in a succinate minimal medium the corresponding fe...

An Ugi multicomponent reaction based two-step strategy was applied to generate medium-sized rings. In the first linear expansion phase, a series of diamines reacted with cyclic anhydrides to produce different lengths of terminal synthetic amino acids as the starting material for the second phase. The Ugi-4-center 3-component reaction was utilized to construct complex medium-sized rings (8-11) b...

In actinomycetes the catabolism products of branched chain amino acids provide biosynthetic precursors for the formation of several lipid-containing antibiotics. We have determined in Nonomuraea sp. ATCC 39727 the effect of valine on production of glycopeptide antibiotic A40926, which is a complex of factors structurally differing in fatty acid moieties. Addition of valine to minimal medium inc...

The propagation of light in a resonant medium with multiple sublevels depends on the populations of and coherences between theses sublevels. We analyze the case of a J= 1/2-J = l/2 transition with arbitrary ground-state polarization in the limit of a weak probe beam. It is found that transverse components of the ground-state orientation lead to a longitudinal component in the eigenpolarizations...

The use of chemically defined culture media for production of biopharmaceuticals has become state of the art. In combination with a suitable feed solution chemically defined media are the most potent driving factor for yield improvement in fed-batch processes. Although various chemically defined media are available of-the-shelf and deliver good results, those media are developed with the aim to...

Alcaligenes faecalis, resistant to the toxic effects of 0.01 M sodium arsenite, was isolated from raw sewage and shown to be capable of oxidizing arsenite to arsenate. When the organisms were grown in chemically defined medium, this conversion was due to the appearance at stationary phase of an intracellular, oxygen-sensitive, inducible enzyme and/or component of the electron transport system; ...

A method for imaging objects in highly scattering turbid media. According to one embodiment of the invention, the method involves using a plurality of intersecting source1 detectors sets and time-resolving equipment to generate a plurality of time-resolved intensity curves for the diffusive component of light emergent from the medium. For each of the curves, the intensities at a plurality of ti...

Light experiences a non-uniformly moving medium as an effective gravitational field, endowed with an effective metric tensor g̃μν = η μν + (n2 − 1)uμuν , n being the refractive index and uμ the fourvelocity of the medium. Leonhardt and Piwnicki [Phys. Rev. A 60, 4301 (1999)] argued that a flowing dielectric fluid of this kind can be used to generate an ’optical black hole’. In the Leonhardt-Piwn...