BACKGROUND Cutaneous injury following impact of a high velocity ball to the skin may result in either erythema or purpura or both. The lesion typically appears as an annular ring of erythema with or without accompanying ecchymosis when the skin is contacted by a paintball, a ping pong ball, a racquetball or a squash ball. PURPOSE To describe a girl with targetoid erythema following impact of ...

Airtime is set as the default routing metric for the ongoing IEEE 802.11s wireless mesh networking standard. The metric is designed to minimize channel resource consumption by accounting for loss rate, bandwidth, and channel characteristics. However, the metric exhibits a noticeable ping-pong effect whose nature is still vague, and the very few references to this in the literature condemn it fo...

The transglutaminase-catalyzed hydrolysis and transfer reactions have been studied kinetically in the forward direction at pH 8 in the presence of a 0.1 M level of the activating metal ion, Ca++. Isotope exchange and product inhibition studies were also conducted. The initial velocity, product inhibition, and isotope exchange patterns are consistent with a ping pong mechanism in which (a) gluta...

We generalize results about the classical Schottky groups to quasiconvex subgroups in negatively curved groups, answering a question of M. Bestvina.

Ping-Pong Electron Transfer through DNA Benjamin Elias, Prof. , Joseph C. Genereux , Jacqueline K. Barton, Prof. 1 * Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125 (USA), Fax: (+1) 626 577 4976 Chimie Organique et Médicinale, Université catholique de Louvain (Belgium) email: Jacqueline K. Barton ([email protected]) Correspondence to Jac...

PIWI proteins and their associated piRNAs protect germ cells from the activity of mobile genetic elements. Two classes of piRNAs—primary and secondary—are defined by their mechanisms of biogenesis. Primary piRNAs are processed directly from transcripts of piRNA cluster loci, whereas secondary piRNAs are generated in an adaptive amplification loop, termed the ping-pong cycle. In mammals, piRNA p...

BACKGROUND Piwi-interacting RNAs (piRNAs) are approximately 24-30 nucleotide regulatory RNAs that are abundant in animal gonads and early embryos. The best-characterized piRNAs mediate a conserved pathway that restricts transposable elements, and these frequently engage a "ping-pong" amplification loop. Certain stages of mammalian testis also accumulate abundant piRNAs of unknown function, whic...