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

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

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

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

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

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

Tamarind (Tamarindus indica linn.) and Sweet Sorghum (Sorghum bicolor L.Moench): their Potential Utilization in Phytotherapy

The use of botanical extracts and essential oil in skin care has been increasing due to greater demand on the part of consumers to use natural ingredients. Tamarind and Sweet Sorghum really have   big potentials  for reaching the public and showcasing its benefits , thus this study could encourage growers to raise more Tamarind and Sweet Sorghum in their areas not only as  food but as a raw material in the production of natural products which are for health and wellness. Both Tamarind and Sweet Sorghum possess skin healing effect which may be attributed to their biologically active components. Tamarind  possess to have bioflavonoids and alkaloids which occur in its leaves, pulp and bark. The bark contains  tannin which are recommended for treatments of inflammation, ulceration and skin disease. Tamarind has  Tartaric acid that makes it possible for tamarind to works wonders on oily skin with pimples and on sun-damaged.  Sweet Sorghum on the other hand contains emulsion, a substance that can give a moisturizing effect on the skin. the majestic phytochemistry of Tamarind and Sweet Sorghum encouraged the researcher  to produce and test  the acceptability, efficacy and safety of different skin care products that are commonly needed by the community. The Tamarind Leaves soap was proven to be highly acceptable in terms of its color, odor, texture, hardness and overall appearance. Both the Tamarind soap and the Sweet Sorghum soap were safe and free from insoluble soap and fatty acid soap. The percent reduction of acne in using Tamarind soap, Sweet Sorghum and Commercial soap have similar effect on the tenth and twelve days of use. The initial means of the treatments ranges from 10.00 pustule to 2.00 pustule. After 12 days of treatment the mean decrease is zero or equivalent to 100% decrease in the number of acne. The result of this study maybe explained with the result on antibacterial property test ( against Staphylococcus A.) of Tamarind soap and Sweet Sorghum Soap. Tamarind soap with 8% extract was found to be most effective in reduction of pimples. The Tamarind shower gel and Sweet Sorghum shower gels were effective against Staphylococcus Aurous. Tamarind Bark Ointment was an effective anti – inflammatory agent particularly on swelling and redness as well as for wound healing. Tamarind scrub salt, shower gel  and liniment  were also highly acceptable and found to be safe and effective. Result on the acceptability of Sweet Sorghum natural products are comparable to the acceptability of Tamarind natural products.  The development of technology for the Production of Natural  Products from Tamarind and Sweet Sorghum is timely, considering the growing consciousness of consumers on safe, organic and healthy natural products. Likewise, this product diversification scheme can promote multi-uses and competitive of the Tamarind and Sweet Sorghum

Optimisation of a one-step PCR assay for the diagnosis of Flavescence doreerelated phytoplasmas in field-grown grapevines and vector populations

Field-infected grapevines and natural populations of Scaphoideus titanus have been analysed to detect group V phytoplasmas associated with flavescence doree in northwestern Italy using nested PCR. A first amplification driven by universal ribosomal primers R16SF2/R2 was followed by a second round assisted by R16(V)F1/R1 primers and subsequent RFLP analysis. To optimize the test, nested PCRs were compared with direct amplification assisted by the group V-specific fAY/rEY primer pair, directed towards other ribosomal sequences. In nested and direct PCRs, respectively, DNAs from 71 and 57 out of 96 grapevines (i.e. 73.9 and 59.3 %) and 51 and 50 out of 108 insects (i.e. 47.2 and 46.3 %) reacted positively. Although it was not possible to determine the subgroup of the phytoplasmas after fAY/rEY amplification, these primers could be used successfully in mass screening of plant material and insect populations. They could detect, in single-step amplification, the phytoplasmas in 80 and 98 % of the plant and insect samples, respectively, that were already indexed as positive using nested PCR. This strongly reduced the number of samples requiring the nested approach, with beneficial effects on costs, labour and risks of the analysis.

Phenotypic and genotypic study on antibiotic resistance and pathogenic factors of staphylococcus aureus isolates from small ruminant mastitis milk in south of italy (Sicily)

Staphyloccoccus aureus is the major cause of mastitis in small ruminants in the Mediterranean farms causing severe losses to dairy industry. Antibiotic treatment has been the most common approach to control these infections. Aim of this study was to investigate antimicrobial resistance (AMR), virulence factors and biofilm-related genes of 84 Sicilian strains of S. aureus isolated from sheep and goats milk during two different periods δT1 (2006-2009) and δT2 (2013-2015). Kirby Bauer method and Polymerase Chain Reaction (PCR) were utilized to monitor AMR and related genes (mecA, tetK, tetM, ermA, ermC). Moreover, toxin genes (tsst-1, sea-see, seg-sej, and sep) and biofilm genes (bap, ica, sasC) were studied. Twenty-six isolates (30.9%) showed multidrug resistance. The two groups showed similar results with exception for higher values of resistance for tilmicosin and lower for sulfamethoxazole and vancomycin of the second group. MecA gene was detected in one isolate. Tetracycline resistance was higher than 20%, with an increase in δT2 group. Toxin genes were found in 5 isolates (5.9%), belonging of δT2 group, while 57 of isolates (67.8%) showed biofilm related genes. The high presence of multi-resistant isolates suggests the need of more responsible use of antibiotic therapy for the control of these infections