In previous studies, we examined three-dimensiional images of a latex bead containing a surface layer of fluorescence whose thickness was determined by physical sectioning. Confocal images of the bead from six different microscopes all exhibited a significantly thicker fluorescent shell than actually present. In contrast, deconvolved wide-field images of the bead produced an image with the corr...

Using a “split –mix” synthesis approach, “One-Bead One-Compound” (OBOC) combinatorial libraries can be generated such that each bead displays only one chemical entity. Tens of thousands to millions of compound-beads can be screened concurrently using a variety of biochemical and cell-based screening methods. Positive beads are then physically isolated for structure determination. Peptide beads ...

A digital microfluidic platform for performing heterogeneous sandwich immunoassays based on efficient handling of magnetic beads is presented in this paper. This approach is based on manipulation of discrete droplets of samples and reagents using electrowetting without the need for channels where the droplets are free to move laterally. Droplet-based manipulation of magnetic beads therefore doe...

We study different configurations of permanent magnets and ferromagnetic circuit, in order to optimize the magnetic field for the so-called “magnetic tweezers” technique, for studing mechanical properties of DNA molecules. The magnetic field is used to pull and twist a micron-sized superparamagnetic bead, tethered to a microscope slide surface by a DNA molecule. The force applied to the bead mu...

RATIONALE Rapidly performing global proteomic screens is an important goal in the post-genomic era. Correlated matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) and fluorescent imaging of photocleavable peptide-coded random bead-arrays was evaluated as a critical step in a new method for proteomic screening that combines many of the advantages of MS with fluorescence-base...

To the Editor: A bewildered 7-year-old girl presented with a smooth plastic bead impacted into the right ear canal. On examination the canal was swollen, irritated and tender owing to previous attempts to remove the bead. The bead, measuring 4 mm in diameter, was pushed almost against the eardrum. A further attempt to remove the bead resulted in an agonised yell — further attempts to remove the...

The roles of different forebrain structures in memory formation in the chick were investigated using restricted radio-frequency lesions. Young chicks will spontaneously peck at a small bright bead. If the bead has been coated with a distasteful substance, the chicks learn not to peck a similar bead on subsequent presentation. Thus, in a single trial chicks learn not to peck at an aversive stimu...

We describe an algorithm for automatic generation of idealized bead figures from recognizable 3D models (animals, humans, etc.). The bead figures approximate the model by a set of cylindrical shapes threaded onto a skeleton of the model. As such, they provide volumetric shape information in addition to the skeleton. The bead figures can be used by applications requiring a simple and compact des...

We give a theoretical analysis of bead motion in tethered-particle experiments, a single-molecule technique that has been used to explore the dynamics of a variety of macromolecules of biological interest. Our analysis reveals that the proximity of the tethered bead to a nearby surface gives rise to a volume-exclusion effect, resulting in an entropic stretching-force on the molecule that change...

An integrated platform for the capture, transport, and detection of individual superparamagnetic microbeads is described for lab-on-a-chip biomedical applications. Magnetic domain walls in magnetic tracks have previously been shown to be capable of capturing and transporting individual beads through a fluid at high speeds. Here it is shown that the strong magnetostatic interaction between a bea...