Asymptotic structure of steady Stokes flow around a rotating obstacle in two dimensions

This paper provides asymptotic structure at spatial infinity of plane steady Stokes flow in exterior domains when the obstacle is rotating with constant angular velocity. The result shows that there is no longer Stokes paradox due to the rotating effect.Comment: 45pages, Corrected typo

Navier-Stokes flow past a rigid body: attainability of steady solutions as limits of unsteady weak solutions, starting and landing cases

Consider the Navier-Stokes flow in 3-dimensional exterior domains, where a rigid body is translating with prescribed translational velocity $-h(t)u_\infty$ with constant vector $u_\infty\in \mathbb R^3\setminus\{0\}$. Finn raised the question whether his steady slutions are attainable as limits for $t\to\infty$ of unsteady solutions starting from motionless state when $h(t)=1$ after some finite time and $h(0)=0$ (starting problem). This was affirmatively solved by Galdi, Heywood and Shibata for small $u_\infty$. We study some generalized situation in which unsteady solutions start from large motions being in $L^3$. We then conclude that the steady solutions for small $u_\infty$ are still attainable as limits of evolution of those fluid motions which are found as a sort of weak solutions. The opposite situation, in which $h(t)=0$ after some finite time and $h(0)=1$ (landing problem), is also discussed. In this latter case, the rest state is attainable no matter how large $u_\infty$ is

A Heat Kernel Approach to Interest Rate Models

We construct default-free interest rate models in the spirit of the well-known Markov funcional models: our focus is analytic tractability of the models and generality of the approach. We work in the setting of state price densities and construct models by means of the so called propagation property. The propagation property can be found implicitly in all of the popular state price density approaches, in particular heat kernels share the propagation property (wherefrom we deduced the name of the approach). As a related matter, an interesting property of heat kernels is presented, too

RAD6-RAD18-RAD5-pathway-dependent tolerance to chronic low-dose ultraviolet light

In nature, organisms are exposed to chronic low- dose ultraviolet light ( CLUV) as opposed to the acute high doses common to laboratory experiments. Analysis of the cellular response to acute high-dose exposure has delineated the importance of direct DNA repair by the nucleotide excision repair pathway(1) and for checkpoint-induced cell cycle arrest in promoting cell survival(2). Here we examine the response of yeast cells to CLUV and identify a key role for the RAD6-RAD18-RAD5 error- free postreplication repair (RAD6 error-free PRR) pathway(3,4) in promoting cell growth and survival. We show that loss of the RAD6 error- free PRR pathway results in DNA-damage-checkpoint- induced G2 arrest in CLUV-exposed cells, whereas wild-type and nucleotide-excision-repair-deficient cells are largely unaffected. Cell cycle arrest in the absence of the RAD6 error- free PRR pathway was not caused by a repair defect or by the accumulation of ultraviolet-induced photoproducts. Notably, we observed increased replication protein A (RPA) and Rad52 - yellow fluorescent protein foci(5) in the CLUV- exposed rad18 Delta cells and demonstrated that Rad52- mediated homologous recombination is required for the viability of the rad18 Delta cells after release from CLUV- induced G2 arrest. These and other data presented suggest that, in response to environmental levels of ultraviolet exposure, the RAD6 error- free PRR pathway promotes replication of damaged templates without the generation of extensive single- stranded DNA regions. Thus, the error- free PRR pathway is specifically important during chronic low- dose ultraviolet exposure to prevent counter- productive DNA checkpoint activation and allow cells to proliferate normally

Combined laser-based measurements for micro- and nano-scale transport phenomena

This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.This paper summarizes our recent works in combined laser-based measurement techniques for investigating micro- and nano-scale transport phenomena. Micron-resolution particle image velocimetry combined with the laser induced fluorescence (LIF) technique has been developed for analyzing velocity and ion concentration distributions simultaneously. The measurement system was based upon a confocal microscope to realize the depth-resolution of approximately 2 μm, and we have applied this technique to liquid-liquid mixing flows, gas-liquid two-phase flows and gas permeation phenomena through membranes. To evaluate the electrostatic potential at a solid-liquid interface (i.e., zeta-potential), the LIF technique was extended with evanescent wave illumination, and only the fluorescent dye within approximately 100 nm from a microchannel wall was irradiated. The technique was applied to microdevices with a surface modification pattern, and the zeta-potential distribution was successfully visualized. Two proposed developments will contribute to novel applications related to microscale multiphase flows or electrokinetics

Unbinding Transition Induced by Osmotic Pressure in Relation to Unilamellar Vesicle Formation

Small-angle X-ray scattering and phase-contrast microscopy experiments were performed to investigate the effect of the osmotic pressure on vesicle formation in a dioleoylphosphatidylcholine (DOPC)/water/NaI system. Multi-lamellar vesicles were formed when a pure lipid film was hydrated with an aqueous solution of NaI. On the other hand, uni-lamellar vesicles (ULVs) were formed when a lipid film mixed with an enough amount of NaI was hydrated. To confirm the effect of the osmotic pressure due to NaI, a free-energy calculation was performed. This result showed that the osmotic pressure induced an unbinding transition on the hydration process, which resulted in ULV formation