Colorectal cancer in elderly patients : An epidemiologic study at University Hospital of Tlemcen

Background : Colorectal cancer has a high incidence and occurs formost patients aged more than 65 years.[1]This population is a very heterogenus group,ranging from the very fit to the very frail.it has often been untreated due to the comorbid diseases,[2.3]however,thanks to comprehensive geriatric assessement which can detect unsuspected health problems,medical care of these patients has been improved[4] The objective of this study is to establish the epidemiological,clinical ,histological and therapeutic profiles of colorectal cancer in this population Methods : We carried out a prospective and descriptive study that includes 69 elderly patients with colorectal cancer treated from january 2016 to december 2018  in medical oncology department at the University Hospital Center of  Tlemcen Results : average age at diagnostic is71years[66-92].The comorbid diseases consist in High Blood Pressure :(46%),diabetes(27%),other cardiovascular diseases(11.6%) and dyslipidemia(6%).Right sided colon was more often achived (57%) than the left one(11%) Adenocarcinoma is the most frequent histological type(59%). The tumor was classifed as stage I (10%),stageII(23%),stageIII(24.6%) and stageIV(26%).Lymphnodes metastasis were observed in 18.5%of cases,metastasis were localised mostly in liver(77%).  58% of patients were assigned to conservative surgery wile 7% inderwent radical one. 26% of patients had adjuvant chemotherapy,20% palliative one associated with target agents and 6 % had concomittent chemoradiotherapy. The mean geriatric score of G8 was 13,so the type of drugs and doses were adapted according to geriatric evaluation.The toxicity of treatment was dominated by diarrhea grade1 in 10% of cases ,neuropathies grade 1 in 7%,vomiting grade 3 in 4% and hand-food syndrom grade3 in 1.5% The average survival is 13 months Conclusion : Aging is one of the factors we need to take into account to establish treatment strategy of elderly with colorectal cancer ,however,patients aged more than 65 years must be treated in the same way as younger subjects together with a personalised strategy considering the comorbidities ,performance status and life styl

Valorisation of Dune Sand Treated with Lime and Scrap Tyre Rubber Powder as a Road Foundation Material.

The purpose of the work presented in this paper is the treatment of dune sand; which is abundant in the region of  Djelfa (Algeria), with different lime and tyre rubber powder in order to valorise them in road construction. Several steps were considered in this research. A method of blend formulation has been proposed which is based on stabilization of the studied sand using a hydraulic binder (lime) and scrap tyre rubber powder with different percentages. For each mixture, the optimum Proctor, shear strength, immediate and immersion CBR index, compressive strength and tensile strength were determined. After that, an analysis of the results was made to examine the influence of treatment agents on the characteristics of the mixtures. The results show that the replacement of lime and tyre rubber powder at optimum content has a positive impact on the physical and mechanical behaviours of the treated dune sand mixtures; increases its compressive and tensile strengths, improves its cohesion and increases its immediate and immersion CBR indexes. The selected optimum formulation has sufficient performances to be used as road material

Optimization of High-Performance-Concrete properties containing fine recycled aggregates using mixture design modeling

This investigation means to predict and modeling the fresh and hardened concrete behavior containing fine aggregates from concrete and brick wastes, for different recycled aggregates substitution rates. To succeed this, the design of experiments DOE method was used. It is observed that slump of recycled concrete is significantly influenced by the content in recycled concrete aggregates (RCA), natural sand (NS) and recycled brick aggregates (RBA), respectively.The compressive strength (CS) reaches a maximum value of 83.48 MPa with factors values of 25% RBA, and 75% RCA. And HPC’s based on RBA sand presented greater values of flexural strength at 7 days than HPC’s based on RCA sand, it was revealed that this is due to the RBA fines pozzolanic reaction and the production of new CSHs, which leads to better cement matrix densification.Under optimal conditions, themaximum desirability is 0.65, who has given HPC no added natural sand, by mixing recycled sands RBA (9.5%) with RCA (90.5%).The statistical terms result show that the expected models are very well correlated with the experimental data and have shown good accuracy

Modeling of a spiral-wound reverse osmosis process and parameter estimation

YesReverse osmosis system has been widely used for the separation of organic and non-organic pollutants present in wastewater. The main aim of this study is to develop a one dimensional steady state model based on the three-parameter Spiegler-Kedem methodology using the gPROMS software and validate it by assessing the performance of membrane rejection for the separation data of aqueous solutions of phenol under different concentrations and pressures. Considerations of the variance of pressure, flow rate, solute concentration, solvent and solute fluxes and mass transfer coefficient along the feed channel were included in the model. Furthermore, an optimization methodology for the gEST parameter estimation tool has been developed in the gPROMS and used with experimental data in order to estimate the best values of the separation membrane parameters and the friction parameter. The simulation results of this model have been corroborated by experimental data

Modélisation et guidage robuste et autonome pour le problème du rendez-vous orbital

Dans cette thèse, nous nous intéressons à deux composantes fondamentales de l'opération du rendez-vous orbital : la navigation relative et le guidage à consommation minimale de carburant. La première partie est consacrée à la modélisation du mouvement relatif de satellites dans un cadre linéaire. Une analyse bibliographique approfondie ainsi que les développements d'une méthode de modélisation et d'une transformation de variables d'état du mouvement relatif sont proposées dans cette partie. Ces développements sont entrepris dans le but de fournir des outils de navigation relative fiables et précis même en présence de perturbations orbitales. Le guidage est abordé dans la seconde partie de la thèse à travers l'élaboration de plusieurs algorithmes de génération de plans de manœuvres pour la mise en œuvre du rendez-vous en temps fixé. Chacun des algorithmes développés est fondé sur des outils théoriques différents tels que les méthodes indirectes de résolution de problèmes de commande optimale basées sur le principe du maximum ou les techniques directes exploitant la discrétisation des problèmes de commande optimale et la programmation linéaire. L'utilisation de ces outils permet de couvrir des objectifs divers, notamment la minimisation de la consommation de carburant et la robustesse vis-à-vis des erreurs de navigation. D'autres algorithmes sont conçus dans le but d'améliorer leur embarcabilité à travers l'utilisation des bases de la mécanique spatiale. Un ensemble de tests de validation et comparaison est réalisé, portant sur des missions réelles ou des exemples académiques issus de la littérature et permettant de mettre en valeur les avantages pratiques les plus pertinents des algorithmes développés.In this thesis, two fundamental steps of the orbital rendezvous are studied: the relative navigation and the minimum-fuel guidance. The first part is devoted to the modeling of spacecraft relative motion under linear assumptions. A comprehensive bibliography review and a novel method of relative motion model design are given in this part as well as a mapping between the various state space variables forms. These developments are undertaken in order to provide reliable and accurate navigation tools in the presence of orbital perturbations. The guidance is considered in the second part through the development of several algorithms for solving the fixed-time rendezvous problem. Each algorithm is developed using different theoretical tools such as indirect methods for solving optimal control problems based on the maximum principle or direct techniques exploiting the discretizing of optimal control problems and linear programming. Various objectives are considered through the use of these tools, including minimization of fuel consumption and robustness toward the navigation errors. Other algorithms are designed in order to improve their practical implementation thanks to the use of orbital mechanics theory. A set of validation tests and comparisons is made, where examples from academic literature and real missions are solved using the different algorithms. This is achieved in order to highlight the most relevant theoretical and practical aspects of the proposed algorithms

Development and Validation of N-nitrosamine Rejection Mathematical Model Using a Spiral-wound Reverse Osmosis Process

yesIn this paper, a one-dimensional mathematical model based on coupled differential and algebraic equations has been developed for analysing the separation mechanism of a N-nitrosamine in a spiral-wound reverse osmosis process. The model is based on Spiegler and Kedem’s work on mass transport and Darcy’s law and concentration polarization to analyse the pressure drop and mass transfer coefficient in the module feed channel respectively. The model is built using the gPROMS software suite and validated using N-nitrosamine rejection experimental data from the literature, obtained by using a pilot-scale cross-flow reverse osmosis filtration system. Analysis results derived from the model corroborate experimental data

Wastewater Treatment by Spiral Wound Reverse Osmosis: Development and Validation of a Two Dimensional Process Model

yesReverse osmosis (RO) has become a significant method for removing salts and organic compounds from seawater and wastewater in recent decades. Spiral-wound module has been widely used due to a number of special features such as high packing density, premium separation and low operating cost. In this paper, a two-dimensional mathematical model is developed for the transport of dilute aqueous solutions through a spiral-wound RO module and the operational characteristics of the process under steady state conditions are analysed. The model is based on the solution-diffusion model coupled with the concentration polarization mechanism. This model yields a set of Differential and Algebraic Equations (DAEs), which are solved using the gPROMS software. The model is validated using experimental data from the literature for the rejection of dimethylphenol as solute in aqueous solutions. The model is then used to simulate the process under steady state conditions to gain deeper insight of the process

Optimal reverse osmosis network configuration for the rejection of dimethylphenol from wastewater

YesReverse osmosis (RO) has long been recognised as an efficient separation method for treating and removing harmful pollutants, such as dimethylphenol in wastewater treatment. This research aims to study the effects of RO network configuration of three modules of a wastewater treatment system using a spiral-wound RO membrane for the removal of dimethylphenol from its aqueous solution at different feed concentrations. The methodologies used for this research are based on simulation and optimisation studies carried out using a new simplified model. This takes into account the solution-diffusion model and film theory to express the transport phenomena of both solvent and solute through the membrane and estimate the concentration polarization impact respectively. This model is validated by direct comparison with experimental data derived from the literature and which includes dimethylphenol rejection method performed on a small-scale commercial single spiral-wound RO membrane system at different operating conditions. The new model is finally implemented to identify the optimal module configuration and operating conditions that achieve higher rejection after testing the impact of RO configuration. The optimisation model has been formulated to maximize the rejection parameters under optimal operating conditions of inlet feed flow rate, pressure and temperature for a given set of inlet feed concentration. Also, the optimisation model has been subjected to a number of upper and lower limits of decision variables, which include the inlet pressure, flow rate and temperature. In addition, the model takes into account the pressure loss constraint along the membrane length commensurate with the manufacturer’s specifications. The research clearly shows that the parallel configuration yields optimal dimethylphenol rejection with lower pressure loss

A New Mixed Iterative Algorithm to Solve the Fuel-Optimal Linear Impulsive Rendezvous Problem

International audienceThe optimal fuel impulsive time-fixed rendezvous problem is reviewed. In a linear setting, it may be reformulated as a non convex polynomial optimization problem for a pre-specified fixed number of velocity increments. Relying on variational results previously published in the literature, an improved mixed iterative algorithm is defined to address the issue of optimization over the number of impulses. Revisiting the primer vector theory, it combines variational tests with sophisticated numerical tools from algebraic geometry to solve polynomial necessary and sufficient conditions of optimality. Numerical examples under circular and elliptic assumptions show that this algorithm is efficient and can be integrated into a rendezvous planning tool

Optimal control to limit the spread of COVID-19 in Italy

We apply optimal control theory to a generalized SEIR-type model. The proposed system has three controls, representing social distancing, preventive means, and treatment measures to combat the spread of the COVID-19 pandemic. We analyze such optimal control problem with respect to real data transmission in Italy. Our results show the appropriateness of the model, in particular with respect to the number of quarantined/hospitalized (confirmed and infected) and recovered individuals. Considering the Pontryagin controls, we show how in a perfect world one could have drastically diminish the number of susceptible, exposed, infected, quarantined/hospitalized, and death individuals, by increasing the population of insusceptible/protected.publishe