Dirichlet Laplacian on curved tubes of a constant cross section in two and three dimensions is investigated. It is shown that if the tube is non{straight and its curvature vanishes asymptotically, there is always a bound state below the bottom of the essential spectrum. An upper bound to the number of these bound states in thin tubes is derived. Furthermore, if the tube is only slightly bent, t...

AIM Burr-hole craniostomy is the most efficient and safe choice for surgical drainage of chronic subdural hematoma (CSDH). Although the twist-drill drainage is also relatively safe and time-saving, it carries the risk of inadequate drainage, brain penetration and hematoma formation. Our modified technique helps in avoiding bleeding and brain penetration. MATERIAL AND METHODS T...

Purpose: During oral fiberoptic intubation, advancement of an endotracheal tube (ETT) into the trachea is occasionally impeded by laryngeal structures. The curved flex tip Parker ETT has been shown to improve the likelihood of successful advancement as opposed to a standard ETT that is advanced in neutral orientation. However, a Parker tube has not been compared to a standard ETT oriented 90 ̊ c...

Taylor dispersion is a key concept in many fields. In the present paper, we characterize the pattern of the complete spatial concentration distribution for laminar tube flow; the obtained simple description is shown to represent the nature of Taylor dispersion. Importantly, we find that during the approach to the longitudinal normality of the transverse mean concentration at the time scale of R...

Using a perturbative argument, we show that in any finite region containing the lowest transverse eigenmode, the spectrum of a periodically curved smooth Dirichlet tube in two or three dimensions is absolutely continuous provided the tube is sufficiently thin. In a similar way we demonstrate absolute continuity at the bottom of the spectrum for generalized Schrödinger operators with a sufficien...