A series of new silver(i) 5,5-diethylbarbiturate (barb) complexes with the formulas [Ag2(μ-barb)2(PPh3)2] (1), [Ag(barb)(PPh2Cy)] (2), [Ag(barb)(PPhCy2)] (3) and [Ag(barb)(PCy3)] (4) (PPh3 = triphenylphosphine, PPh2Cy = diphenylcyclohexylphosphine, PPhCy2 = dicyclohexylphenylphosphine and PCy3 = tricyclohexylphosphine) were synthesized and fully characterized by elemental analysis, IR, NMR, ESI...

Comparative study of completed down feathers from seven of the major tracts of newly-hatched Silver Campine chicks reveals tract-specific differences in the total length of the primary group of barbs and in the length of their barbule-free tips. Two classes of barbs can be distinguished on the basis of overall length in feathers of any one of the tracts: (a) those barbs that form from the first...

this study was conducted to determine the optimal dietary protein requirement for lemon fin barb hybrid fingerlings. triplicate groups of fish (1.00 ± 0.05 g) were fed twice a day until apparent satiation with five isocaloric (16 kj/g) diets containing varying protein level ranging from 20 to 40% for 60 days. survival was not affected by the dietary protein level. the weight gain and specific g...

The evolution of bilaterally symmetric feathers is a fundamental process leading toward flight. One major unsolved mystery is how the feathers of a single bird can form radially symmetric downy feathers and bilaterally symmetric flight feathers. In developing downy feather follicles, barb ridges are organized parallel to the long axis of the feather follicle. In developing flight-feather follic...

Melanin has been associated with increased resistance to abrasion, decreased wear and lowered barb breakage in feathers. But, this association was inferred without considering barb position along the rachis as a potentially confounding variable. We examined the cross-sectional area, breaking force, breaking stress, breaking strain and toughness of melanized and unmelanized barbs along the entir...

A. Reduction-closed barbed congruence (Section II) Definition 28 (Reduction-closed barbed congruence). Let L be a process calculus, in which a reduction relation −→L and barb predicates ↓a , for each a in a given set of names, have been defined. A relationR on the processes of L is context-closed if PRQ implies C[P ]RC[Q], for each context C of L; the relation is barb-preserving if for any name...

Asymmetry in flight feather vane width is a major functional innovation associated with the evolution of flight in the ancestors of birds. However, the developmental and morphological basis of feather shape is not simple, and the developmental processes involved in vane width asymmetry are poorly understood. We present a theoretical model of feather morphology and development that describes the...

BarA of Streptomyces virginiae is a specific receptor protein for a member of butyrolactone autoregulators which binds to an upstream region of target genes to control transcription, leading to the production of the antibiotic virginiamycin M(1) and S. BarA-binding DNA sequences (BarA-responsive elements [BAREs]), to which BarA binds for transcriptional control, were restricted to 26 to 29-nucl...

In a feather, there are distinct morphologies along the proximal-distal axis. The proximal part is a cylindrical stalk (calamus), whereas the distal part has barb and barbule branches. Here we focus on what molecular signaling activity can modulate feather stem cells to generate these distinct morphologies. We demonstrate the drastic tissue remodeling during feather cycling which includes initi...