Immobilized lipase from Candida antarctica (Novozym 435) was used in organic media to catalyze esterifications of vitamins (ascorbic acid and retinol) from hydroxy acid. We described the synthesis of retinyl L-lactate by transesterification between retinol and L-methyl lactate with yield reaching 90% and the synthesis of ascorbyl L-lactate by transesterification between ascorbic acid and L-meth...

Pentaerythritol tetranitrate reductase, which reductively liberates nitrite from nitrate esters, is related to old yellow enzyme. Pentaerythritol tetranitrate reductase follows a ping-pong mechanism with competitive substrate inhibition by NADPH, is strongly inhibited by steroids, and is capable of reducing the unsaturated bond of 2-cyclohexen-1-one.

The ping-pong model for the red cell anion exchange system postulates that the transport protein band 3 can exist in two different conformations, one in which the transport site faces the cytoplasm (Ei) and another in which it faces the outside medium (Eo). This model predicts that an increase in intracellular chloride should increase the fraction of sites in the outward-facing, unloaded form (...

The E. coli protein WrbA is an FMN-dependent NAD(P)H:quinone oxidoreductase that has been implicated in oxidative defense. Three subunits of the tetrameric enzyme contribute to each of four identical, cavernous active sites that appear to accommodate NAD(P)H or various quinones, but not simultaneously, suggesting an obligate tetramer with a ping-pong mechanism in which NAD departs before oxidiz...

Germline-specific Piwi-interacting RNAs (piRNAs) protect animal genomes against transposons and are essential for fertility. piRNAs targeting active transposons are amplified by the ping-pong cycle, which couples Piwi endonucleolytic slicing of target RNAs to biogenesis of new piRNAs. Here, we describe the identification of a transient Amplifier complex that mediates biogenesis of secondary piR...

“Ping-pong” fractures (PPF) are depressed skull fractures typical of newborns. PPF usually result from head injury and, rarely, may cause severe long-term neurological sequelae. The management of PPF is still controversial. The goal of this paper is to present a case of “spontaneous” ping-pong fracture and to review the pertinent literature of the last 20 years. We report on a newborn who prese...

Problem statement: Human ping-pong players determine the stroke trajectory according to their experience before the ball enters their court. However, to enable a humanoid robot to select the appropriate stroke motion based on skills learned from 3D motion, important patterns must be generated to simplify the complex 3D motion. Approach: This study developed an effective strategy for teaching pi...

Incorporating eeective feedback mechanisms in an interactive game system can certainly enhance the user's performance of the tasks. This paper presents the modular design and evaluation of a Virtual Reality system, called the Virtual Ping-Pong System. Our system supports an interactive ping-pong game which is implemented on top of the VRML platform. The main objective of our system is to enhanc...

Table 7. This table contains statistics regarding applying locality optimization to the TSP application running on 6 hosts with false sharing for different k (number of jobs contending for a page). Applying locality optimizations decreases dramatically the number of DSM messages (page lookup and transfer). The added overhead imposed by ping-pong treatment mechanism and increased number of threa...

Tratamento conservador da fratura em ping pong lactente utilizando aspiração a vácuo – relato de caso / Conservative treatment of fracture in an infant using vacuum aspiration - case report