Polymeric drugs carriers of methacrylic and acrylic derivatives

Summary 2-Amino-thiazole reacts with methacryloyl or acryloyl chloride to give amides which are polymerized. Hydrolyses of polymers have been studied with and without enzymatic catalysis in a synthetic gastric liquid.     

Étude théorique et expérimentale d’un synchronisateur primaire numérique pour signaux MIC

Bit synchronizers are used in satellite data communications systems to restore the data rate. They provide means to data detection. The paper concerns the theoretical analysis supported by the simulation and the pratical measurements of a digital self bit synchronizer implemented with standart ttl logic. This self bit synchronizer is composed of a non linear element which delivers from the sampled and quantized pcm signal a spectral line at frequency twice the data rate. This spectral line is filtered by a digital phase locked loop and is used to drive a digital matched filter data detector. Theoretical and experimental results show a very small mean acquisition time (about 4 or 5 bit duration) and a degradation lower than 2 dB for snr ranging from +2 dB to +12 dB.     

Size variation and optical absorption of sol-gel Ag nanoparticles doped SiO2 thin film

In this research, we have focused on the formation of Ag nanoparticles dispersed in SiO₂ matrix using sol-gel method. The influences of the metal concentration on the size variation of Ag nanoparticles and the size effect on the surface plasmon absorption have been studied. Sol-gel silica thin films containing Ag particles were synthesized by dip-coating on soda-lime glasses. The molar ratio of Ag / Si was chosen from 0.2% to 8%. All films were dried in air at 100 °C for 1 h. Using X-ray photoelectron spectroscopy, the Ag / Si ratios in the prepared films have been measured. In addition, it was shown that the prepared matrix was a stoichiometric composition as SiO₂, and the synthesized nanoparticles were mainly in the metallic state. Size and distribution of the nanoparticles were measured by high resolution scanning as well as transmission electron microscopy and also atomic force microscopy analyses for low and high Ag concentrations, respectively. We have found that by decreasing the Ag / Si ratio from 8 to 0.2 mol%, the particle size reduces from 95 to 4 nm with a nearly spherical shape. UV-visible spectrophotometry showed that the size reduction of the Ag nanoparticles for the Ag / Si molar ratios ranging from 8 to 0.2 mol% leads to an intensity reduction of the absorption peak and a blue shift from 460 to 410 nm.     

Topological design,routing and capacity dimensioning for ISL networks in broadband LEO satellite systems

This paper considers the network design of intersatellite link (ISL) networks in broadband LEO satellite systems, where the major challenge is the topology dynamics. First, a general method to design convenient ISL topologies for connection‐oriented operation is presented, and a reference topology for numerical studies is derived. A permanent virtual topology is then defined on top of the orbiting physical one, thus forming a framework for discrete‐time dynamic traffic routing. On this basis, heuristic and optimization approaches for the combined routing and dimensioning task, operating on discrete time steps, are presented and their performance is numerically compared. It is shown that minimizing the worst‐case link capacity is an appropriate target function, which can be formulated as linear optimization problem with linear constraints. Using linear programming (LP) techniques, the dimensioning results are clearly better than with simple heuristic approaches. Copyright © 2001 John Wiley & Sons, Ltd.     

Numerical analysis of blast-induced wave propagation using FSI and ALEmulti-material formulations

As explosive blasts continue to cause casualties in both civil and military environments, there is a need to identify the dynamic interaction of blast loading with structures, to know the shock mitigating mechanisms and, most importantly, to identify the mechanisms of blast trauma. This paper examines the air-blast simulation using Arbitrary Lagrangian Eulerian (ALE) multi-material formulation. It will explain how the fluid–structure interaction (FSI) can be simulated using a coupling algorithm for the treatment of the fluid as a moving media by a moving mesh using ALE formulation and how the structure is treated on a deformable mesh using a Lagrangian formulation. To validate the numerical approach, as well as to prove its ability to simulate complicated scenarios, comparison of three distinct blast scenarios, i.e., blast from C-4 and TNT in open space and blast on a circular steel plate, with the experimental data was performed. The predicted numerical results match very well with those of experiments. This computational approach is able to accurately predict the relevant aspects of the blast–structure interaction problem, including the blast wave propagation in the medium and the response of the structure to blast loading.     

Optimal design of multi-response experiments using semi-definite programming

Optimal design of multi-response experiments for estimating the parameters of multi-response linear models is a challenging problem. The main drawback of the existing algorithms is that they require the solution of many optimization problems in the process of generating an optimal design that involve cumbersome manual operations. Furthermore, all the existing methods generate approximate design and no method for multi-response n-exact design has been cited in the literature. This paper presents a unified formulation for multi-response optimal design problem using Semi-Definite Programming (SDP) that can generate D-, A- and E-optimal designs. The proposed method alleviates the difficulties associated with the existing methods. It solves a one-shot optimization model whose solution selects the optimal design points among all possible points in the design space. We generate both approximate and n-exact designs for multi-response models by solving SDP models with integer variables. Another advantage of the proposed method lies in the amount of computation time taken to generate an optimal design for multi-response models. Several test problems have been solved using an existing interior-point based SDP solver. Numerical results show the potentials and efficiency of the proposed formulation as compared with those of other existing methods. The robustness of the generated designs with respect to the variance-covariance matrix is also investigated.     

Caractérisation expérimentale des boucles numériques à verrouillage de phase en présence de bruit

This paper presents experimental results for digital phase locked loops (DPLL), as obtained from a setup designed according to a previously proposed modélisation of DPLLs An automatic test bed has been implemented. Results concern both acquisition and tracking of a sine wave, with and without noise, by either first order or second order loops, or loops including a sequential filter. Close agreement between experimental results and theoretical ones, when available, indicate correct design and functionning of the setup and test-bed. Moreover, results not available from theory are provided, such as: influence of real components on performance, acquisition range for noisy input signal, distribution of the acquisition time. Finally, this experimental study delivers results for second order loops.     

Delay analysis for interlan traffic using two suitable TDMA satellite access schemes

Two demand assignment time division multiple access (TDMA) satellite access schemes that are suitable for providing flexible interconnections of local area networks are compared by means of two simulations; Fifo Ordered Demand Assignment/Information Bit Energy Adaptive (FODA/IBEA) and Combined Fixed Reservation Assignment (CFRA). A unique simulation tool was used, a meshed network of very small aperture terminals (VSATs) under the control of a master station was considered and similar networking conditions were applied to both access schemes. The generated traffic had two components with different level of burstiness; bulk traffic and interactive traffic. The performance evaluated is the delay for each traffic component. We show that CFRA is best when connecting clusters of only a few stations and even individual stations exchanging light traffic. On the other hand, FODA/IBEA is better suited to interconnect networks, or within networks with many hosts, where heavy traffic is more likely. © 1997 John Wiley & Sons, Ltd.     

Grading of gliomas using transfer learning on MRI images

Magnetic Resonance Materials in Physics, Biology and Medicine - Despite the critical role of Magnetic Resonance Imaging (MRI) in the diagnosis of brain tumours, there are still many pitfalls in the...     

Radiomics-based machine-learning method to diagnose prostate cancer using mp-MRI: a comparison between conventional and fused models

Magnetic Resonance Materials in Physics, Biology and Medicine - Multiparametric MRI (mp-MRI) has been significantly used for detection, localization and staging of Prostate cancer (PCa). However,...