Anti-aging activities of extracts from Tunisian medicinal halophytes and their aromatic constituents

Six medicinal halophytes widely represented in North Africa and commonly used in traditional medicine were screened for pharmacological properties to set out new promising sources of natural ingredients for cosmetic or nutraceutical applications. Thus, Citrullus colocynthis, Cleome arabica, Daemia cordata, Haloxylon articulatum, Pituranthos scoparius and Scorzonera undulata were examined for their in vitro antioxidant (DPPH scavenging and superoxide anion-scavenging, β-carotene bleaching inhibition and iron-reducing tests), antibacterial (microdi- lution method, against four human pathogenic bacteria) and anti-tyrosinase activities. Besides, their aromatic com- position was determined by RP-HPLC. H. articulatum shoot extracts exhibited the strongest antioxidant activity and inhibited efficiently the growth of Salmonella enterica and Escherichia coli. P. scoparius and C. arabica inhibited slightly monophenolase, whereas H. articulatum was the most efficient inhibitor of diphenolase activity. Furthermore, H. articulatum exhibited the highest aromatic content (3.4 % DW), with dopamine as the major com- pound. These observations suggest that shoot extract of H. articulatum, and to a lesser extent of C. arabica, could otic as well as new natural skin lightening agents. Also, possible implication of aromatic compounds in anti-tyrosinase activity is discussed

A mechanism-based approach to modeling ductile fracture.

Ductile fracture in metals has been observed to result from the nucleation, growth, and coalescence of voids. The evolution of this damage is inherently history dependent, affected by how time-varying stresses drive the formation of defect structures in the material. At some critically damaged state, the softening response of the material leads to strain localization across a surface that, under continued loading, becomes the faces of a crack in the material. Modeling localization of strain requires introduction of a length scale to make the energy dissipated in the localized zone well-defined. In this work, a cohesive zone approach is used to describe the post-bifurcation evolution of material within the localized zone. The relations are developed within a thermodynamically consistent framework that incorporates temperature and rate-dependent evolution relationships motivated by dislocation mechanics. As such, we do not prescribe the evolution of tractions with opening displacements across the localized zone a priori. The evolution of tractions is itself an outcome of the solution of particular, initial boundary value problems. The stress and internal state of the material at the point of bifurcation provides the initial conditions for the subsequent evolution of the cohesive zone. The models we develop are motivated by in-situ scanning electron microscopy of three-point bending experiments using 6061-T6 aluminum and 304L stainless steel, The in situ observations of the initiation and evolution of fracture zones reveal the scale over which the failure mechanisms act. In addition, these observations are essential for motivating the micromechanically-based models of the decohesion process that incorporate the effects of loading mode mixity, temperature, and loading rate. The response of these new cohesive zone relations is demonstrated by modeling the three-point bending configuration used for the experiments. In addition, we survey other methods with the potential to provide more detailed information about the near tip deformation fields

A multivariant secure framework for smart mobile health application

This is an accepted manuscript of an article published by Wiley in Transactions on Emerging Telecommunications Technologies, available online: https://doi.org/10.1002/ett.3684 The accepted version of the publication may differ from the final published version.Wireless sensor network enables remote connectivity of technological devices such as smart mobile with the internet. Due to its low cost as well as easy availability of data sharing and accessing devices, the Internet of Things (IoT) has grown exponentially during the past few years. The availability of these devices plays a remarkable role in the new era of mHealth. In mHealth, the sensors generate enormous amounts of data and the context-aware computing has proven to collect and manage the data. The context aware computing is a new domain to be aware of context of involved devices. The context-aware computing is playing a very significant part in the development of smart mobile health applications to monitor the health of patients more efficiently. Security is one of the key challenges in IoT-based mHealth application development. The wireless nature of IoT devices motivates attackers to attack on application; these vulnerable attacks can be denial of service attack, sinkhole attack, and select forwarding attack. These attacks lead intruders to disrupt the application's functionality, data packet drops to malicious end and changes the route of data and forwards the data packet to other location. There is a need to timely detect and prevent these threats in mobile health applications. Existing work includes many security frameworks to secure the mobile health applications but all have some drawbacks. This paper presents existing frameworks, the impact of threats on applications, on information, and different security levels. From this line of research, we propose a security framework with two algorithms, ie, (i) patient priority autonomous call and (ii) location distance based switch, for mobile health applications and make a comparative analysis of the proposed framework with the existing ones.Published onlin

Cristallisation polytherme de l'epsomite à partir d'une saumure naturelle. Application du système : Na+, K+, Mg2+/Cl-, SO42-//H2O

Sebkha El Melah Natural Brine is a complex high concentrated aqueous solution. To study this kind of saline solutions many authors assimilate them to a quinary system represented by Na+, K+, Mg2+/Cl-, SO42-//H2O. In the case of Sebkha El Melah brine, magnesium and sulfate ions seems to be sufficiently high to recover Epsomite (MgSO4.7H2O). The aim of this work is firstly to apply the above mentioned diagram allowing the production of the considered salt, calculate the recovery rates and secondly to test the conceived process at the laboratory scale

Étude de l'évaporation d'une saumure naturelle. Corrélation conductivité-concentrations ioniques (Na+, K+, Mg2+, Cl-,SO24)

During evaporation natural brine crystallizes different salts. The limit between two steps is generally pointed using the density of the liquid phase in equilibrium with the crystallized salt. This method presents some disadvantages when used in the field especially when the pretreated brine is used to recover epsomite by refrigerating it. The aim of this work is to establish a correlation between the measured conductivity and the specific density of a considered brine and then with its ionic composition. The plotted parameters will be used to define the highest limit before extracting magnesium sulfate from the brine

Clustering methods comparison: application to source based detection of botclouds

International audienc

Chemin de cristallisation informatisé : analyse critique des données

In former works we described the DPAO method "Diagram of Phases Computer-assisted" and we applied it to the study of the isothermal and isobar evaporation of a point mixture representing the natural brine resulting from Sebkha El Melah de Zarzis (Tunisia). The quality of the data, as well in precision as in number, is discussed in this presentation, whatever the method of adopted advance: computerized or manual

Évaporation isotherme et isobare des saumures du sud tunisien suivie par la méthode DPAO

Evaporation is the most important process to recover salts from Tunisian natural brines. So it's essential to visualize the geometrical representations of the system involved in this case Na$^+$, K$^+$, Mg$^{2+}$/CI$^-$,SO$_4^{2-}$ - H$_2$O. Those representations allow us to navigate through the diagram and to draw crystallisation paths. Many techniques have been successfully tested over the last century such as the van't Hoff projection and the Janecke one, and were used to resolve the complexity of the multicomponent problem. The DPAO is a computer based visualization method proposed to enable a simulation of brine evaporation and to foresee the solid phases deposed during the process