Resonant Ultrasonic Particle Manipulators and their Applications in Sensor Systems

The paper describes the use of ultrasonic standing waves as bulk acoustic wave actuators, exploiting the acoustic radiation forces within the standing wave to move biological cells or other particles. This is a technology with the potential to enhance many forms of microflow-based sensors. Example applications discussed include half-wavelength filters, flow-through chambers which move cells from one fluid medium into another (washing the cells), and quarter wavelength chambers that attract cells to a solid boundary such as the face of a sensor. Microfabricated devices are described, including resonators with multiple sub-wavelength resonances, which are driven by multilayer thick film PZT actuators

On the stability of J∗−^*-derivations

In this paper, we establish the stability and superstability of $J^*-$derivations in $J^*-$algebras for the generalized Jensen--type functional equation $$rf(\frac{x+y}{r})+rf(\frac{x-y}{r})= 2f(x).$$ Finally, we investigate the stability of $J^*-$derivations by using the fixed point alternative

Upper Extremity Joint Dynamics During Walker Assisted Gait: A Quantitative Approach Towards Rehabilitative Intervention

Background Many children with spastic diplegic cerebral palsy (CP) use anterior or posterior walkers to aid ambulation. Prolonged use may lead to upper extremity (UE) pathology later in life, including arthritis and joint contractures. Purpose This study analyzes the dynamics (kinematics and kinetics) of the shoulder (glenohumeral), elbow, and wrist joints during anterior and posterior walker use. It also examines the dynamic effects of adjusting handle height and grip rotation. Methods Ten children with CP underwent motion analysis with upper and lower extremity marker sets and six-degree-of-freedom instrumented walker handles, while using both anterior and posterior walkers. One child underwent the same analysis, with added trials for wrist derotation (adjusted axial grip rotation) and wrist plus elbow derotation (adjusted handle height). A validated kinematic and kinetic model was applied to calculate UE joint angles, joint reaction forces (JRFs), and joint reaction moments (JRMs). Results Surprisingly, no statistically significant differences in UE angles, JRFs, or JRMs were observed between anterior and posterior walkers. Wrist derotation, however, decreased the flexion JRM seen at the wrist, and elbow derotation decreased the flexion JRM seen at the elbow. Conclusion Anterior and posterior walkers produce similar UE motion and peak loading values. Wrist and elbow joint derotation alters the dynamic effects experienced by the UEs. UE motion analysis during aided gait can be useful for optimizing UE loading conditions to limit pathology later in life

Noah's ark conservation will not preserve threatened ecological communities under climate change

Background: Effective conservation of threatened ecological communities requires knowledge of where climatically suitable habitat is likely to persist into the future. We use the critically endangered Lowland Grassland community of Tasmania, Australia a

Charge and mass effects on the evaporation of higher-dimensional rotating black holes

To study the dynamics of discharge of a brane black hole in TeV gravity scenarios, we obtain the approximate electromagnetic field due to the charged black hole, by solving Maxwell's equations perturbatively on the brane. In addition, arguments are given for brane metric corrections due to backreaction. We couple brane scalar and brane fermion fields with non-zero mass and charge to the background, and study the Hawking radiation process using well known low energy approximations as well as a WKB approximation in the high energy limit. We argue that contrary to common claims, the initial evaporation is not dominated by fast Schwinger discharge.Comment: Published version. Minor typos corrected. 29 pages, 5 figure

Interacting Random Walkers and Non-Equilibrium Fluctuations

We introduce a model of interacting Random Walk, whose hopping amplitude depends on the number of walkers/particles on the link. The mesoscopic counterpart of such a microscopic dynamics is a diffusing system whose diffusivity depends on the particle density. A non-equilibrium stationary flux can be induced by suitable boundary conditions, and we show indeed that it is mesoscopically described by a Fourier equation with a density dependent diffusivity. A simple mean-field description predicts a critical diffusivity if the hopping amplitude vanishes for a certain walker density. Actually, we evidence that, even if the density equals this pseudo-critical value, the system does not present any criticality but only a dynamical slowing down. This property is confirmed by the fact that, in spite of interaction, the particle distribution at equilibrium is simply described in terms of a product of Poissonians. For mesoscopic systems with a stationary flux, a very effect of interaction among particles consists in the amplification of fluctuations, which is especially relevant close to the pseudo-critical density. This agrees with analogous results obtained for Ising models, clarifying that larger fluctuations are induced by the dynamical slowing down and not by a genuine criticality. The consistency of this amplification effect with altered coloured noise in time series is also proved.Comment: 8 pages, 7 figure

Normal tissue complication probability (NTCP) parameters for breast fibrosis: pooled results from two randomised trials

Introduction: the dose–volume effect of radiation therapy on breast tissue is poorly understood. We estimate NTCP parameters for breast fibrosis after external beam radiotherapy.Materials and methods: we pooled individual patient data of 5856 patients from 2 trials including whole breast irradiation followed with or without a boost. A two-compartment dose volume histogram model was used with boost volume as the first compartment and the remaining breast volume as second compartment. Results from START-pilot trial (n?=?1410) were used to test the predicted models.Results: 26.8% patients in the Cambridge trial (5?years) and 20.7% patients in the EORTC trial (10?years) developed moderate-severe breast fibrosis. The best fit NTCP parameters were BEUD3(50)?=?136.4?Gy, ?50?=?0.9 and n?=?0.011 for the Niemierko model and BEUD3(50)?=?132?Gy, m?=?0.35 and n?=?0.012 for the Lyman Kutcher Burman model. The observed rates of fibrosis in the START-pilot trial agreed well with the predicted rates.Conclusions: this large multi-centre pooled study suggests that the effect of volume parameter is small and the maximum RT dose is the most important parameter to influence breast fibrosis. A small value of volume parameter ‘n’ does not fit with the hypothesis that breast tissue is a parallel organ. However, this may reflect limitations in our current scoring system of fibrosi

Monte-Carlo study of scaling exponents of rough surfaces and correlated percolation

We calculate the scaling exponents of the two-dimensional correlated percolation cluster's hull and unscreened perimeter. Correlations are introduced through an underlying correlated random potential, which is used to define the state of bonds of a two-dimensional bond percolation model. Monte-Carlo simulations are run and the values of the scaling exponents are determined as functions of the Hurst exponent H in the range -0.75 <= H <= 1. The results confirm the conjectures of earlier studies