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Packing problems, such as how densely objects can fill a volume, are among the most ancient and persistent problems in mathematics and science. For equal spheres, it has only recently been proved that the face-centered cubic lattice has the highest possible packing fraction phi=pi/18 approximately 0.74. It is also well known that certain random (amorphous)(More)
the conditional probability of finding a particle at position x after time t with the particle located for t ϭ 0 at x ϭ 0. In Fig. 3A, we show the result of p(x, t) for ⌫ ϭ 4 at four different times, which are all greater than t c. Self-diffusion of particles causes p(x, t) to broaden with time. Despite the simplicity of the physical situation describing SF(More)
BACKGROUND The safety and efficacy of istradefylline, a selective adenosine A(2A) receptor antagonist, was evaluated in a 12-week, double-blind study in levodopa-treated Parkinson disease (PD) subjects with motor complications. METHODS Levodopa-treated PD subjects (n = 395) received istradefylline 20 mg/day (n = 163), istradefylline 60 mg/day (n = 155),(More)
In this Letter, we report on the densest-known packings of congruent ellipsoids. The family of new packings consists of crystal arrangements of spheroids with a wide range of aspect ratios, and with density phi always surpassing that of the densest Bravais lattice packing phi approximately equal to 0.7405. A remarkable maximum density of phi approximately(More)
Tetrahedra may be the ultimate frustrating, disordered glass forming units. Our experiments on tetrahedral dice indicate the densest (volume fraction phi=0.76+/-.02, compared with phi(sphere)=0.64), most disordered, experimental, random packing of any set of congruent convex objects to date. Analysis of MRI scans yield translational and orientational(More)
" Diffuse correlation spectroscopy " (DCS) is a technology for non-invasive transcranial measurement of cerebral blood flow (CBF) that can be hybridized with " near-infrared spectroscopy " (NIRS). Taken together these methods hold potential for monitoring hemodynamics in stroke patients. We explore the utility of DCS and NIRS to measure effects of(More)
Spontaneous formation of colonies of bacteria or flocks of birds are examples of self-organization in active living matter. Here, we demonstrate a form of self-organization from nonequilibrium driving forces in a suspension of synthetic photoactivated colloidal particles. They lead to two-dimensional "living crystals," which form, break, explode, and(More)
New functional materials can in principle be created using colloids that self-assemble into a desired structure by means of a programmable recognition and binding scheme. This idea has been explored by attaching 'programmed' DNA strands to nanometre- and micrometre- sized particles and then using DNA hybridization to direct the placement of the particles in(More)
Porous materials have potential applications in pho-tonic crystals, 1 membranes, 2 and data storage 3 and as catalyst supports. 4 Increasing interest in these areas has driven extensive research efforts to explore novel materials and processes. Although significant progress has been made in the development of new lithographic procedures for the fabrication(More)