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The growth and division of Staphylococcus aureus was monitored by atomic force microscopy (AFM) and thin-section transmission electron microscopy (TEM). A good correlation of the structural events of division was found using the two microscopies, and AFM was able to provide new additional information. AFM was performed under water, ensuring that all(More)
We observed that the oscillation period of MinD within rod-like and filamentous cells of Escherichia coli varied by a factor of 4 in the temperature range from 20 degrees C to 40 degrees C. The detailed dependence was Arrhenius, with a slope similar to the overall temperature-dependent growth curve of E. coli. The detailed pattern of oscillation, including(More)
Alzheimer's disease (AD) is a devastating disorder that leads to memory loss and dementia. Neurodegeneration of cholinergic neurons in the septum and other basal forebrain areas is evident in early stages of AD. Glutamatergic neurons are also affected early in AD. In these stages, amyloid-β-peptide (Aβ) plaques are present in the hippocampus and other(More)
Type IV pili play an important role in bacterial adhesion, motility, and biofilm formation. Here we present high-resolution atomic force microscopy (AFM) images of type IV pili from Pseudomonas aeruginosa bacteria. An individual pilus ranges in length from 0.5 to 7 microm and has a diameter from 4 to 6 nm, although often, pili bundles in which the(More)
Aeromonas salmonicida subsp. salmonicida, a bacterial pathogen of Atlantic salmon, has no visible pili, yet its genome contains genes for three type IV pilus systems. One system, Tap, is similar to the Pseudomonas aeruginosa Pil system, and a second, Flp, resembles the Actinobacillus actinomycetemcomitans Flp pilus, while the third has homology to the(More)
We report AFM measurements of binding events between immunoglobulin G (IgG) and protein A (PA) on the surface of live Staphylococcus aureus bacteria. The experiments were carried out with IgG molecules tethered via CM-amylose linkers to thiol SAMs on gold-coated AFM tips. For comparison, a model system consisting of protein A molecules tethered to thiol(More)
When solving the Symmetric Positive Definite (SPD) linear system Ax = b with the conjugate gradient method, the smallest eigenvalues in the matrix A often slow down the convergence. Consequently if the smallest eigenvalues in A could be somehow " removed " , the convergence may be improved. This observation is of importance even when a preconditioner is(More)
In this article, a new extension of affine arithmetic is introduced. This technique is based on a quadratic form named general quadratic form. We focus here on the computation of reliable bounds of a function over a hypercube by using this new tool. Some properties of first quadratic functions and then polynomial ones are reported. In order to show the(More)