Development of Zinc‐Specific iCEST MRI as an Imaging Biomarker for Prostate Cancer

The healthy prostate contains the highest concentration of mobile zinc in the body. As this level decreases dramatically during the initial development of prostate cancer, in vivo detection of prostate zinc content may be applied for diagnosis of prostate cancer. Using ¹⁹F ion chemical exchange saturation transfer magnetic resonance imaging (iCEST MRI) and TF‐BAPTA as a fluorinated Zn‐binding probe with micromolar sensitivity, we show that iCEST MRI is able to differentiate between normal and malignant prostate cells with a 10‐fold difference in contrast following glucose‐stimulated zinc secretion in vitro. The iCEST signal decreased in normal prostate cells upon downregulation of the ZIP1 zinc transporter. In vivo, using an orthotopic prostate cancer mouse model and a transgenic adenocarcinoma of the mouse prostate (TRAMP) model, a gradual decrease of >300 % in iCEST contrast following the transition of normal prostate epithelial cells to cancer cells was detected.     

Macroscopic resonant tunneling in an rf-SQUID flux qubit under a single-cycle sinusoidal driving

We experimentally demonstrate the observation of macroscopic resonant tunneling(MRT) phenomenon of the macroscopic distinct flux states in a radio frequency superconducting quantum interference device(rf-SQUID) under a singlecycle sinusoidal driving.The population of the qubit exhibits interference patterns corresponding to resonant tunneling peaks between states in the adjacent potential wells.The dynamics of the qubit depends significantly on the amplitude,frequency,and initial phase of the driving signal.We do the numerical simulations considering the intra-well and interwell relaxation mechanism,which agree well with the experimental results.This approach provides an effective way to manipulate the qubit population by adjusting the parameters of the external driving field.     

A lattice Boltzmann method for viscous free surface waves in two dimensions

We propose a new method based on the combination of the lattice Boltzmann equation (LBE) and the kinematic boundary condition (KBC) method to simulate viscous free surface wave in two dimensions. In our method, the flow field is modeled by LBE, whereas the free surface is explicitly tracked by the local height function, which is calculated by the KBC method. The free surface boundary condition (FSBC) for LBE is revised from previous researches. Interpolation‐supplemented lattice Boltzmann (ISLB) method is introduced, which enables our approach to be applied on arbitrary, nonuniform mesh grids. Five cases are simulated respectively to validate the LBE–KBC method: the stationary flow and the solitary waves simulated by the revised‐FSBC are more accurate than the one obtained by the former‐FSBC; numerical results of standing waves show that our method is compatible to the existing two‐dimensional finite‐volume scheme; cases of small amplitude Stokes wave and waves traveling over a submerged bar show good agreement on wave celerity, wavelength, wave amplitude and wave period between numerical results and corresponding analytical solutions and/or experiment data.Copyright © 2012 John Wiley & Sons, Ltd.     

Radiobiological features of the anti‐cancer strategies involving synchrotron X‐rays

Synchrotrons are opening new paths in innovative anti‐cancer radiotherapy strategies. Indeed, the fluence of X‐rays induced by synchrotrons is so high (10⁶ times higher than standard medical irradiators) that it enables the production of X‐ray beams tunable in energy (monochromatic beams) and in size (micrometric beams). Monochromatic synchrotron X‐ray beams theoretically permit photoactivate high‐Z elements to be introduced in or close to tumours in order to increase the yield of damage by enhanced energy photoabsorption. This is notably the case of attempts with iodinated contrast agents used in tumour imaging (the computed tomography therapy approach) and with platinated agents used in chemotherapy (the PAT‐Plat approach). Micrometric synchrotron X‐ray beams theoretically permit very high radiation doses to accumulate in tumours by using arrays of parallel microplanar beams that spare the surrounding tissues (the microbeam radiation therapy approach). These anti‐cancer applications of synchrotron radiation have been developed at the European Synchrotron Radiation Facility to be applied to glioma, one of the tumour tissues most refractory to standard treatments. In the present paper the molecular and cellular mechanisms involved in these three approaches are reviewed, in the context of recent advances in radiobiology. Furthermore, by considering the unavoidable biases, an attempt to propose a comparison of the different results obtained in preclinical trials dealing with rats bearing tumours is given.     

Stability analysis of viscous Z-pinch plasma with a sheared axial flow

Within the magnetohydrodynamics （MHD） frame, we analyse the effect of viscosity on magneto-Rayleigh Taylor （MRT） instability in a Z-pinch configuration by using an exact method and an approximate method separately. It is demonstrated that the plasma viscosity indeed has a stabilization effect on the MRT mode in the whole wavenumber region, and its influence increases with the perturbation wavenumber increasing. After the characteristics and feasibility of the approximate method have been investigated, we apply it to the stability analysis of viscous plasma where a sheared axial flow （SAF） is involved, and we attain an analytical dispersion relation. It is suggested that the viscosity and the SAF are complemental with each other, and a wide wavenumber range of perturbation is possible to be restrained if the SAF and the viscosity are large enough. Finally, we calculate the possible value of viscosity parameter according to the current experimental conditions, and the results show that since the value of viscosity is much less than the threshold value, its mitigation effect is small enough to be neglected. The role of the viscosity in the stabilization becomes considerable only if special techniques are so developed that the Z-pinch plasma viscosity can be increased greatly.     

Three-dimensional multi-relaxation time lattice-Boltzmann model for the drop impact on a dry surface at large density ratio

Extensive application of the multiphase lattice Boltzmann model to realistic fluid flows is often restricted by the numerical instabilities induced at high liquid-to-gas density ratios, and at low viscosities. In this paper, a three-dimensional multi-relaxation time (MRT) lattice Boltzmann model with an improved forcing scheme is reported for simulating multiphase flows at high liquid-to-gas density ratios and relatively high Reynolds numbers. The model is based on a recently presented model in the literature. Firstly, the MRT multiphase model is evaluated by verifying Laplace’s law and achieving thermodynamic consistency for a static droplet. Then, a relationship between the fluid–solid interaction potential parameter and contact angle is investigated. Finally, the improved three-dimensional MRT Lattice Boltzmann model is employed in the simulation of the impingement of a liquid droplet onto a flat surface for a range of Weber and Reynolds numbers. The dynamics of the droplet spreading is reproduced and the predicted maximum spread factor is in good agreement with experimental data published in the literature.     

Sectoral thermal emitter for testing of modern IR systems

The paper presents multi-sector stable IR grey body radiation source, that can be used for testing of MRT. Its main element is monolithic metal plate with a test pattern, made of material with high thermal conductivity. On the surface of the test plate the sectors of different emissivity are created during manufacturing process. As a result when viewed by a thermal camera those sectors exhibit thermal contrast depending mainly on the radiative properties of each sector. The value of thermal contrast between particular sectors can be adjusted by changing the temperature of a test plate with respect to ambient. The emissivity values of particular sectors have been calculated and the procedure of adjusting the thermal contrast has been described, as well as the technology used to create the test plate. The model of described emitter has been tested and the results of temperature values obtained from thermal camera were compared with theoretical, calculated figures. The proposed emitter is dedicated for testing and calibrating of modern observations IR systems.