Electrophoretic Deformation of Individual Transfer RNA Molecules Reveals Their Identity.

It has been hypothesized that the ribosome gains additional fidelity during protein translation by probing structural differences in tRNA species. We measure the translocation kinetics of different tRNA species through ∼3 nm diameter synthetic nanopores. Each tRNA species varies in the time scale with which it is deformed from equilibrium, as in the translocation step of protein translation.

Fixed-gap tunnel junction for reading DNA nucleotides.

Previous measurements of the electronic conductance of DNA nucleotides or amino acids have used tunnel junctions in which the gap is mechanically adjusted, such as scanning tunneling microscopes or mechanically controllable break junctions. Fixed-junction devices have, at best, detected the passage of whole DNA molecules without yielding chemical information. Here, we report on a layered tunnel junction in which the tunnel gap is defined by a dielectric layer, deposited by atomic layer deposition.

Mechanical properties of the extracellular matrix of the aorta studied by enzymatic treatments.

The microarchitecture of different components of the extracellular matrix (ECM) is crucial to our understanding of the properties of a tissue. In the study presented here, we used a top-down approach to understand how the interplay among different fibers determines the mechanical properties of real tissues. By selectively removing different elements of the arterial wall, we were able to measure the contribution of the different constituents of the ECM to the mechanical properties of the whole tissue.

AutoMicromanager: a microscopy scripting toolkit for LABVIEW and other programming environments.

We present a scripting toolkit for the acquisition and analysis of a wide variety of imaging data by integrating the ease of use of various programming environments such as LABVIEW, IGOR PRO, MATLAB, SCILAB, and others. This toolkit is designed to allow the user to quickly program a variety of standard microscopy components for custom microscopy applications allowing much more flexibility than other packages. Included are both programming tools as well as graphical user interface classes allowing a standard, consistent, and easy to maintain scripting environment.

Distinct defects in collagen microarchitecture underlie vessel-wall failure in advanced abdominal aneurysms and aneurysms in Marfan syndrome.

An aneurysm of the aorta is a common pathology characterized by segmental weakening of the artery. Although it is generally accepted that the vessel-wall weakening is caused by an impaired collagen metabolism, a clear association has been demonstrated only for rare syndromes such as the vascular type Ehlers-Danlos syndrome. Here we show that vessel-wall failure in growing aneurysms of patients who have aortic abdominal aneurysm (AAA) or Marfan syndrome is not related to a collagen defect at the molecular level.