Complementary Sections Research Articles

Chemoenzymatic, enantiocomplementary, total asymmetric synthesis of leukotrienes-B3 and -B4

The ketone 3 has been resolved using various enzyme-catalysed reactions and the enantiomer (+)-3 was transformed into the benzoate 8 while (–)-3 was converted into the esters 10 and 11; compounds 8 and 10 are complementary sections of leukotriene B4 while compounds 8 and 11 are late-stage synthons for leukotriene B3.

An early critique of Bacon's Sylva Sylvarum: Edmund Chilmead's treatise on sound

Summary Edmund Chilmead (1610–54), a little-known scholar and musician, was the author of a possibly unique testimony to the interest among English natural philosophers in the nature of sound and philosophical music theory during the years following the publication of Francis Bacon's Sylva Sylvarum (1626). Chilmead's ‘An Examination … of the Naturall History’ is a manuscript treatise which takes the form of twenty ‘Quaeres’ on the second and third centuries of experiments of the Sylva which are concerned with the nature of sound. In the treatise, Chilmead reveals his familiarity with the developments in the field of musical acoustics made by the French natural philosopher Marin Mersenne (1588–1648) and his circle. The paper falls into two complementary sections. In the first, Feingold gives an account of Chilmead's life and career (which has hitherto never been fully documented) in order to place him in the context of the intellectual and social milieu of Oxford and London during this period. In the secon...

Mesozoic complementary crust in the North Atlantic

Detailed surveys of complementary oceanic crustal sections have been carried out over Mesozoic magnetic anomalies M4–M0 (∼116–110 Myr BP) in the North Atlantic Ocean. We report here reconstructions of these crustal sections, one on the North American plate and one on the African plate, as they once existed together at the ridge crest using a statistical least squares technique, as well as by eye. The reconstructions allow a test of plate rigidity and consequently a refinement of the reconstruction of the whole North Atlantic in these times. Previous reconstructions had the uncertainty that the correct sections were being matched; the gentle curvature of the Mesozoic plate boundary provides little constraint along the strike of the boundary. The unique local pattern of the magnetic anomalies and their offsets in the surveyed areas allows an unambiguous match.

Ray analysis of multimode, optical fibres

A ray analysis of a multimode, step or graded index fibre can be conveniently divided into two complementary sections. Those phenomena associated with the fibre core, such as pulse propagation, source excitation, power absorption, scattering and inhomogeneities are viewed as building blocks on a basis of ray trajectories and ray classes as predicted by Snell’s laws. Cladding phenomena, such as absorption and ray tunnelling are superposable building blocks based on Fresnel’s laws and their generalizations.

Hilbert transform relations for products

A general formula for the Hilbert transform of a product of complex-valued functions is developed. Certain simplifications are then exhibited for products often encountered in the context of modulation and signal processing. The approach chosen is one of frequency partitioning; this permits signal definition on complementary sections of the frequency axis and leads to compact and easily manipulated expressions.

Recombination in Bacteriophage T4

Publisher Summary This chapter discusses that study on genetic recombination in phage T4 shows the participating DNA molecules are broken and rejoined during the process. It appears, likely, that breakage and rejoining may account for all recombination, as the extent of breakage, as measured by physical methods, is in rather good agreement with the extent of exchange, as measured by genetic methods. In genetic crosses, there are on the average 20 exchanges per genome and these are apparently clustered to some extent. Isotope transfer experiments indicate that there is a bimodal distribution of parental DNA; progeny particles, which receive any parental label, receive on the average 5–10%, or less than 1% of a chromosomal equivalent. The chapter explores that the joining of parental fragments occurs in several steps, which are mediated by specific enzymes. In intermediate structures, complementary sections of different parental origin are held together by hydrogen bonds involved in base pairing. Subsequently, the parental fragments become covalently linked. Physically hybrid regions in base-paired structures may be genetically heterozygous. They become homozygous only after the hybrid DNA is replicated or repaired. Average recombination frequencies per unit length DNA are higher in T4 crosses than in most other systems. One map unit corresponds to 100–200 nucleotide pairs, both according to physical and genetic measurements. However, the average recombination frequency per unit length DNA is not equal over the entire T4 genome.

Śrautakośa, Encyclopedia of Vedic Sacrificial Ritual, Comprising the Two Complementary Sections, Namely, the Sanskrit Section and the English Section. Volume I. English Section, Part II

Śrautakośa, Encyclopedia of Vedic Sacrificial Ritual, Comprising the Two Complementary Sections, Namely, the Sanskrit Section and the English Section. Volume I. English Section, Part II