The nicotinic acetylcholine receptor (AChR) is the prototype of ligand-gated ion channels. Here, we calculate the dynamics of the muscle AChR using normal modes. The calculations reveal a twist-like gating motion responsible for channel opening. The ion channel diameter is shown to increase with this twist motion. Strikingly, the twist motion and the increase in channel diameter are not observe...

Turbulent forced convective mass (heat) transfer downstream of blockages with round and elongated holes in a rectangular channel was studied. The blockages and the channel had the same 12:1 (width-to-height ratio) cross section, and a distance equal to twice the channel height separated consecutive blockages. The diameter of the holes was either 0.5 or 0.75 of the height of the channel. Naphtha...

The mechanosensitive channel of large conductance, which serves as a model system for mechanosensitive channels, has previously been crystallized in the closed form, but not in the open form. Ensemble measurements and electrophysiological sieving experiments show that the open-diameter of the channel pore is >25 Å, but the exact size and whether the conformational change follows a helix-tilt or...

Nonelectrolyte polymers of poly(ethylene glycol) (PEG) were used to estimate the diameter of the ion channel formed by the Bacillus anthracis protective antigen 63 (PA(63)). Based on the ability of different molecular weight PEGs to partition into the pore and reduce channel conductance, the pore appears to be narrower than the one formed by Staphylococcus aureus alpha-hemolysin. Numerical inte...

A new atmospheric pressure ionization mass spectrometer (API-MS) interface has been developed to allow the control of ion transmission through the first vacuum stage of the mass spectrometer. The described interface uses a dual-heated capillary and a dual-inlet ion funnel design. Two electrosprays, aligned with the dual-capillary inlet, are used to introduce ions from different solutions indepe...

Microfluidic approaches to microbubble production are generally disadvantaged by low yield and high susceptibility to (micro)channel blockages. This paper presents an alternative method of producing microbubbles of 2.6 μm mean diameter at concentrations in excess of 30 × 10(6) mL(-1). In this method, the nitrogen gas flowing inside the liquid jet is disintegrated into spray of microbubble when ...