Disentangling time in a near-field approach to scanning probe microscopy.

Microwave microscopy has recently attracted intensive effort, owing to its capability to provide quantitative information about the local composition and the electromagnetic response of a sample. Nonetheless, the interpretation of microwave images remains a challenge as the electromagnetic waves interact with the sample and the surrounding in a multitude of ways following different paths: microwave images are a convolution of all contributions. In this work we show that examining the time evolution of the electromagnetic waves allows us to disentangle each contribution, providing images with striking quality and unexplored scenarios for near-field microscopy.

Two-dimensional enzyme diffusion in laterally confined DNA monolayers.

Addressing the effects of confinement and crowding on biomolecular function may provide insight into molecular mechanisms within living organisms, and may promote the development of novel biotechnology tools. Here, using molecular manipulation methods, we investigate restriction enzyme reactions with double-stranded (ds)DNA oligomers confined in relatively large (and flat) brushy matrices of monolayer patches of controlled, variable density. We show that enzymes from the contacting solution cannot access the dsDNAs from the top-matrix interface, and instead enter at the matrix sides to diffuse two-dimensionally in the gap between top- and bottom-matrix interfaces.

Distance optical sensor for quantitative endoscopy.

We present a novel optical sensor able to measure the distance between the tip of an endoscopic probe and the anatomical object under examination. In medical endoscopy, knowledge of the real distance from the endoscope to the anatomical wall provides the actual dimensions and areas of the anatomical objects. Currently, endoscopic examination is limited to a direct and qualitative observation of anatomical cavities.

Image transmission and radiation by truncated linearly polarized multimode fiber.

We study the use of individual multimode fibers for the purposes of microendoscopy. We discuss the question of image decomposition in the several modes propagating over the fiber and their scattering at the truncated fiber end. We derive analytically the scattering matrix of the "fiber-to-air" interface, we quantify the extent of intermodal coupling, and we evaluate the radiation diagram from the fiber end.

A method for dynamic subtraction MR imaging of the liver.

Background: Subtraction of Dynamic Contrast-Enhanced 3D Magnetic Resonance (DCE-MR) volumes can result in images that depict and accurately characterize a variety of liver lesions. However, the diagnostic utility of subtraction images depends on the extent of co-registration between non-enhanced and enhanced volumes. Movement of liver structures during acquisition must be corrected prior to subtraction.