Parabolic temperature profile and second-order temperature jump of a slightly rarefied gas in an unsteady two-surface problem

The behavior of a slightly rarefied monatomic gas between two parallel plates whose temperature grows slowly and linearly in time is investigated on the basis of the kinetic theory of gases. This problem is shown to be equivalent to a boundary-value problem of the steady linearized Boltzmann equation describing a rarefied gas subject to constant volumetric heating. The latter has been recently studied by Radtke, Hadjiconstantinou, Takata, and Aoki (RHTA) as a means of extracting the second-order temperature jump coefficient. This correspondence between the two problems gives a natural interpretation to the volumetric heating source and explains why the second-order temperature jump observed by RHTA is not covered by the general theory of slip flow for steady problems. A systematic asymptotic analysis of the time-dependent problem for small Knudsen numbers is carried out and the complete fluid-dynamic description, as well as the related half-space problems that determine the structure of the Knudsen layer and the coefficients of temperature jump, are obtained. Finally, a numerical solution is presented for both the Bhatnagar-Gross-Krook model and hard-sphere molecules. The jump coefficient is also calculated by the use of a symmetry relation; excellent agreement is found with the result of the numerical computation. The asymptotic solution and associated second-order jump coefficient obtained in the present paper agree well with the results by RHTA that are obtained by a low variance stochastic method

Bladder cancer with urinary diversion by a sigmoid colon conduit after transverse colon stoma

Introduction Sigmoid conduit is one of the methods for achieving urinary diversion, but it is performed less frequently than ileal conduit and ureterostomy. Herein, we report a case in which a sigmoid colon conduit was performed after nephrostomy and transverse colostomy. Case presentation A 70‐year‐old man was referred to our hospital because of a bladder tumor. Computed tomography and transurethral biopsy revealed advanced bladder cancer with ureteral and rectal invasion. Despite drug therapy, the tumor progressed. Thus, nephrostomy and transverse colostomy were performed for urinary and fecal diversion, respectively. Subsequently, chemotherapy was administered for 8 months. As nephrostomy‐related complications occurred frequently during chemotherapy, a sigmoid colon conduit was performed instead of nephrostomy for urinary diversion to improve the patient's quality of life. Conclusion In patients with advanced bladder cancer requiring a double stoma of the urinary and fecal tracts, sigmoid colon conduit may be selected as a urinary diversion method

Slip and jump boundary conditions for the compressible Navier-Stokes equations based on an asymptotic analysis of the Boltzmann equation

The slip/jump coefficients and the Knudsen-layer functions for the time-dependent version of the generalized slip-flow theory have been obtained for the Ellipsoidal Statistical (ES) model up to the second order of the Knudsen number expansion. In particular, simple but exact conversion formulas between the ES and Bhatnagar–Gross–Krook (BGK) model have been established

Magnetic metal-complex-conducting copolymer core–shell nanoassemblies for a single-drug anticancer platform

Nanoparticulate agents for magnetic drug delivery systems (DDSs) have extensive applications in targeted drug delivery, contrast imaging and therapeutics. However, no simple synthetic method for magnetic DDS agents has been developed without the need to add magnetic nanoparticles. Here, we describe the one-step fabrication of ‘all-in-one’ magneto-assemblies using an ‘inorganic-metal-salt-free’ method, involving spontaneous self-assembly of the water-insoluble prodrug μ-oxo-bis(N,N′-ethylenebis(salicylideniminato)iron) [Fe(salen)] (magnetic core) with polypyrrole (PPy)-b-polycaprolactone (PCL) smart diblock copolymers. In the system, PCL serves as a heat-responsive core scaffold, and PPy serves as an electronic core-size controller and pH-responsive shell. This core–shell nanocomposite has a high-loading capacity (~90%), and the core size is tunable by incorporating albumin or gum arabic as bio-coating agents, which also provide colloidal stability, biocompatibility and thermo-stability. Fe(salen), which has intrinsic antitumor activity, also has ubiquitous magnetic properties, which are dramatically enhanced in these molecular assemblies with magnetic coupling. Moreover, these multifunctional nanoassemblies can be delivered magnetically, can serve as magnetic resonance imaging contrast agents, can generate magneto-hyperthermal effects and can enable magnetic field-triggered release of Fe(salen) molecules under acidic conditions