It is critical that scuba divers and submariners can assess the possible effects of changes in pressure of their surrounding atmosphere as otherwise they may be affected by the “bends” (or, to use its more formal name, Decompression Sickness (DCS)) which can be severely debilitating and even fatal. For scuba diving there is an enormous literature on how to change water depth safely to avoid any...

We present two unusual presentations of decompression sickness manifesting at previous injury sites after deep mixed-gas recreational diving. While previous injury is often cited as a predisposing factor in decompression illness, formal case reports of this phenomenon are rare in the diving literature.

Gaseous supersaturation can be induced under steady-state conditions when two inert gases are transmitted in opposite directions across any system comprising a diffusion barrier adjacent to a zone of limited convective capacity. This has many implications for bubble formation in vivo and can explain the occurence of symptoms of decompression sickness without decompression.

Exercising before, during, or after diving is proscribed because of the assumption that it would increase incidence of decompression sickness. Our findings show that exercise performed in a timely fashion before diving or during decompression will reduce the number of venous gas bubbles formed. Exercise after diving did not increase the number of bubbles. Nitric oxide seems to play a protective...

We describe a numerical procedure to construct a modified velocity field that does not have any mean flow. Using this procedure, we present two results. First, we show that, in the absence of the mean flow, spiral defect chaos collapses to a stationary pattern comprising textures of stripes with angular bends. The quenched patterns are characterized by mean wave numbers that approach those uniq...

We propose a method for adaptive waveguide bends using homogeneous, nonmagnetic, and isotropic materials, which simplifies the parameters of the bends to the utmost extent. The proposed bend has an adaptive and compact shape because of all the flat boundaries. The nonmagnetic property is realized by selecting OB'/OC = 0.5. Only two nonmagnetic isotropic dielectrics are needed throughout, and th...

We propose a simple two-dimensional acoustic crystal to realize topologically protected edge states for acoustic waves. The acoustic crystal is composed of a triangular array of core-shell cylinders embedded in a water host. By utilizing the point group symmetry of two doubly degenerate eigenstates at the Γ point, we can construct pseudo-time-reversal symmetry as well as pseudo-spin states in t...

We study the elastic response of a wormlike polymer chain with reversible kinklike structural defects. This is a generic model for (a) the double-stranded DNA with sharp bends induced by binding of certain proteins, and (b) effects of trans-gauche rotations in the backbone of the single-stranded DNA. The problem is solved both analytically and numerically by generalizing the well-known analogy ...

We investigated the planar covariation of lower limb segment elevation angles during bipedal walking in macaques to elucidate the mechanisms underlying the origin and evolution of the planar law in human walking. Two Japanese macaques and four adult humans walking on a treadmill were recorded, and the time course of the elevation angles at the thigh, shank and foot segments relative to the vert...