Background: PutA from Escherichia coli is a bifunctional enzyme and transcriptional repressor in proline catabolism. Results: Steady-state and transient kinetic data revealed a mechanism in which the two enzymatic reactions are coupled by an activation step. Conclusion: Substrate channeling in PutA exhibits hysteretic behavior. Significance: This is the first kinetic model of bi-enzyme activity...

In a typical ultra-deep high-temperature and high-pressure heterogeneous reservoir in Xinjiang, gas channeling quickly occurs during injection because of the heterogeneity reservoir, low viscosity injection, high gas-oil fluidity ratio. The identification prediction methods development were studied. First, discrimination parameters determined by numerical simulation method. According to ratio o...

Energetic positrons propagating along low index directions in a crystal interact strongly with the periodic array of atoms via a process known as channeling. The trajectories of such channeled positrons can be manipulated to sample di€erent spatial regions in the crystal. Here we report the ®rst observations of channeling e€ects on in̄ight annihilation radiation from positrons traversing a thin ...

This paper presents the results of numerical simulations of a crystalline undulator based on the channeling of 20 GeV electrons and positrons. The device considered is characterized by a small amplitude and a short period of periodic bending. Calculations have been performed accounting for all-atom interactions using the MBN Explorer software package. The effect of low crystal thickness (less t...

We have recorded channeling patterns produced by 1 to 2 MeV protons aligned with <111> axes in 55 nm thick silicon crystals which exhibit characteristic angular structure for deflection angles up to and beyond the axial critical angle, a. Such large angular deflections are produced by ions incident on atomic strings with small impact parameters, resulting in trajectories which pass through sev...

The use of a two stage crystal collimation system in the RHIC yellow ring is examined. The system includes a copper beam scraper and a bent silicon crystal. While scrapers were installed in both of the RHIC rings before the year 2000 run, the crystal is installed for the 2001 run in one ring only, forming a two stage collimation system there. We present simulations of the expected channeling th...

A methodology for the gridding and upscaling of geological systems characterized by channeling is presented. The overall approach entails the use of a flow-based gridding procedure for the generation of variably refined grids capable of resolving the channel geometry, a specialized full-tensor upscaling method to capture the effects of permeability connectivity, and the use of a fluxcontinuous ...

Combined high precision RBS/channeling, NRA/channeling and perturbed angular studies were used to characterize near-stoichiometric and congruent LiNbO3 single crystals. In congruent LiNbO3 two non-equivalent Li sites are distinguished whereas in near-stoichiometric LiNbO3 only one of them exists. A comparison of the experimental results with Monte Carlo simulations was performed to check the va...

Pelleting inactivates SODle viruses and aggregates other dispersed :material. Methods for separation should be developed in which desired particles are always kept in suspension. Rotors that cODlbine continuous-flow centrifugation with isop"ycnic banding can achieve this effect. In our SySteDl a liquid density gradient is set up in a spinning rotor next to the wall in each of 4 sector-shaped cO...