Roaming in acetaldehyde.

We investigate roaming in the photodissociation of acetaldehyde (CH3CHO), providing insights into the contrasting roaming dynamics observed for this molecule compared to formaldehyde. We carry out trajectory studies for full-dimensional acetaldehyde, supplemented with an analysis of a two-degree-of-freedom restricted model and obtain evidence for two distinct roaming pathways. Trajectories exhibit roaming at both shorter (9-11.

Support vector machines for learning reactive islands.

We develop a machine learning framework that can be applied to data sets derived from the trajectories of Hamilton's equations. The goal is to learn the phase space structures that play the governing role for phase space transport relevant to particular applications. Our focus is on learning reactive islands in two degrees-of-freedom Hamiltonian systems.

Influence of mass and potential energy surface geometry on roaming in Chesnavich's model.

Chesnavich's model Hamiltonian for the reaction + H is known to exhibit a range of interesting dynamical phenomena including roaming. The model system consists of two parts: a rigid, symmetric top representing the ion and a free H atom. We study roaming in this model with focus on the evolution of geometrical features of the invariant manifolds in phase space that govern roaming under variations of the mass of the free atom and a parameter that couples radial and angular motion.

The phase space geometry underlying roaming reaction dynamics.

Recent studies have found an unusual way of dissociation in formaldehyde. It can be characterized by a hydrogen atom that separates from the molecule, but instead of dissociating immediately it roams around the molecule for a considerable amount of time and extracts another hydrogen atom from the molecule prior to dissociation. This phenomenon has been coined roaming and has since been reported in the dissociation of a number of other molecules.

[Local immune defects--products of free oxygen radicals].

The discussion about the supporting task of four main active oxygen dependent mechanisms mediating and modulating immune signals was included in the work, along with the discussion on antioxidants influencing these mechanisms. The former include xanthine-oxidase, cyclooxygenase, lipoxygenase, aldehyde oxygenase metabolic chains. Currently, we are just beginning to realize that active oxygen and antioxidants can modulate the induction of physiological signals, and that these effects are not limited to the immune system.