Faithful Estimation of Dynamics Parameters from CPMG Relaxation Dispersion Measurements

This work examines the robustness of fitting of parameters describing conformational exchange (kex, pa/b, and Δω) processes from CPMG relaxation dispersion data. We have analyzed the equations describing conformational exchange processes for the intrinsic inter-dependence of their parameters that leads to the existence of multiple equivalent solutions, which equally satisfy the experimental data. We have used Monte-Carlo simulations and fitting to the synthetic data sets as well as the direct 3-D mapping of the parameter space of kex, pa/b, and Δω to quantitatively assess the degree of the parameter inter-dependence. The demonstrated high correlation between parameters can preclude accurate dynamics parameter estimation from NMR spin-relaxation data obtained at a single static magnetic field. The strong parameter inter-dependence can readily be overcome through acquisition of spin-relaxation data at more than one static magnetic field thereby allowing accurate assessment of conformational exchange properties

Velocity-sensorless tracking control and identification of switched-reluctance motors

International audienceWe present a solution to the speed sensorless control problem for switched-reluctance motors under parametric uncertainty. Our main results guarantee velocity tracking control for velocity references with constant reference acceleration under the assumption that the load torque, the rotor inertia, the resistance and inductances are unknown. Under a persistency of excitation condition on a function which depends only on reference trajectories, we guarantee uniform global asymptotic stability therefore, we establish conditions for the identification of the physical parameters of the system. Our theoretical findings are supported by illustrative simulation results

Exponential stabilization of switched-reluctance motors via speed-sensorless feedback

International audienceWe solve the control problem of switched-reluctance motors without velocity measurements. Our controller is composed of a loop in the mechanical dynamics which consists of a PI2 D controller and a "tracking" controller closing an inner loop with the stator currents dynamics. The PI2 D controller consists in a linear proportional derivative controller in which the measurement of velocities is replaced by approximate derivatives of angular position. Then a double integrator is added, composed of an integral of the angular position errors and a second integral correction term in function of the approximate derivative. We show global exponential stability and illustrate the performance of our controller in numerical simulations

A novel PID-based control approach for switched-reluctance motors

International audienceWe propose a control strategy for switched-reluctance motors with unknown load, which consists in two separate control loops, for the rotor (mechanical) dynamics and the stator (electrical) dynamics. The novelty of the approach resides in using an alternative rotor model which corresponds to that of an harmonic oscillator hence, it is linear in the rotation coordinates. The control law is of proportional-integral-derivative type and it is implemented through a virtual control input, generated via the mechanical torque of electrical origin. A second control loop is closed around the stator dynamics via a current tracking controller. As far as we know, we establish for the first time global exponential stability considering that the load torque is unknown

Total Degree Formula for the Generic Offset to a Parametric Surface

We provide a resultant-based formula for the total degree w.r.t. the spatial variables of the generic offset to a parametric surface. The parametrization of the surface is not assumed to be proper.Comment: Preprint of an article to be published at the International Journal of Algebra and Computation, World Scientific Publishing, DOI:10.1142/S021819671100680

Speed-sensorless control of switched-reluctance motors with uncertain payload

International audienceWe present a controller for switched-reluctance motors without velocity measurements and provide, to the best of our knowledge, the first result establishing global exponential stability. Our controller is composed of an "internal" tracking control loop for the stator dynamics and an "external" control loop based on the so-called PI2 D controller. The latter consists in a linear proportional derivative controller in which the mea- surement of velocities is replaced by approximate derivatives. Furthermore, a double integrator is added to compensate for the load uncertainty. We illustrate our theoretical findings with numerical simulations

Evidence for a Novel Reaction Mechanism of a Prompt Shock-Induced Fission Following the Fusion of 78Kr and 40Ca Nuclei at E/A =10 MeV

An analysis of experimental data from the inverse-kinematics ISODEC experiment on 78Kr+40Ca reaction at a bombarding energy of 10 AMeV has revealed signatures of a hitherto unknown reaction mechanism, intermediate between the classical damped binary collisions and fusion-fission, but also substantially different from what is being termed in the literature as fast fission or quasi fission. These signatures point to a scenario where the system fuses transiently while virtually equilibrating mass asymmetry and energy and, yet, keeping part of the energy stored in a collective shock-imparted and, possibly, angular momentum bearing form of excitation. Subsequently the system fissions dynamically along the collision or shock axis with the emerging fragments featuring a broad mass spectrum centered around symmetric fission, relative velocities somewhat higher along the fission axis than in transverse direction, and virtually no intrinsic spin. The class of massasymmetric fission events shows a distinct preference for the more massive fragments to proceed along the beam direction, a characteristic reminiscent of that reported earlier for dynamic fragmentation of projectile-like fragments alone and pointing to the memory of the initial mass and velocity distribution.Comment: 5 PAGES, 6 FIGURE

Monitoring multiple myeloma by idiotype-specific peptide binders of tumor-derived exosomes.

Abstract Tumor-derived exosomes (TDEs) play a pivotal role in tumor establishment and progression, and are emerging biomarkers for tumor diagnosis in personalized medicine. To date, there is a lack of efficient technology platforms for exosome isolation and characterization. Multiple myeloma (MM) is an incurable B-cell malignancy due to the rapid development of drug-resistance. MM-released exosomes express the immunoglobulin B-cell receptor (Ig-BCR) of the tumor B-cells, which can be targeted by Idiotype-binding peptides (Id-peptides). In this study, we analyzed the production of MM-released exosomes in the murine 5T33MM multiple myeloma model as biomarkers of tumor growth. To this end, we selected Id-peptides by screening a phage display library using as bait the Ig-BCR expressed by 5T33MM cells. By FACS, the FITC-conjugated Id-peptides detected the MM-released exosomes in the serum of 5T33MM-engrafted mice, levels of which are correlated with tumor progression at an earlier time point compared to serum paraprotein. These results indicate that Id-peptide-based recognition of MM-released exosomes may represent a very sensitive diagnostic approach for clinical evaluation of disease progression

Kinematical coincidence method in transfer reactions

A new method to extract high resolution angular distributions from kinematical coincidence measurements in binary reactions is presented. Kinematic is used to extract the center of mass angular distribution from the measured energy spectrum of light particles. Results obtained in the case of 10Be+p-->9Be+d reaction measured with the CHIMERA detector are shown. An angular resolution of few degrees in the center of mass is obtained.Comment: 6 Page 10 Figures submitted to Nuclear Instruments and Methods

Dual targeting of HER3 and MEK may overcome HER3-dependent drug-resistance of colon cancers

Although the medical treatment of colorectal cancer has evolved greatly in the last years, a significant portion of early-stage patients develops recurrence after therapies. The current clinical trials are directed to evaluate new drug combinations and treatment schedules. By the use of patient-derived or established colon cancer cell lines, we found that the tyrosine kinase receptor HER3 is involved in the mechanisms of resistance to therapies. In agreement, the immunohistochemical analysis of total and phospho-HER3 expression in 185 colorectal cancer specimens revealed a significant correlation with lower disease-free survival. Targeting HER3 by the use of the monoclonal antibody patritumab we found induction of growth arrest in all cell lines. Despite the high efficiency of patritumab in abrogating the HER3-dependent activation of PI3K pathway, the HER2 and EGFR-dependent MAPK pathway is activated as a compensatory mechanism. Interestingly, we found that the MEK-inhibitor trametinib inhibits, as expected, the MAPK pathway but induces the HER3-dependent activation of PI3K pathway. The combined treatment results in the abrogation of both PI3K and MAPK pathways and in a significant reduction of cell proliferation and survival. These data suggest a new strategy of therapy for HER3-overexpressing colon cancers