Modified insulator semiconductor electrode with functionalized nanoparticles for Proteus mirabilis bacteria biosensor development

The development of enzymatic sensors for biological purposes such as biomedicine, pharmacy, food industry, and environmental toxicity requires the purification step of the enzyme. To prevent the loss of the enzyme activity, a new strategy is held in order to immobilize the bacteria. It will constitute the biological sensing element leading to a high operational stability and multiple adaptations to various conditions such as temperature, pH and ionic strength changes. In this work we describe the development of a urea biosensor by immobilizing Proteus mirabilis bacteria onto an insulator–semiconductor electrode on functionalized Fe₃O₄ nanoparticles (NPs), using cationic, Poly (allylamine hydrochloride) then anionic, Poly (sodium 4-styrenesulfonate) polyelectrolytes, BSA (serum bovin albumin), and glutaraldehyde as a cross-linking agent. The response of P. mirabilis to urea addition is evaluated in homogeneous and heterogeneous phases. Before the immobilization step, the activity of urease produced from the P. mirabilis bacteria was attempted using the ion ammonium selective electrodes (ISEs). Adhesion of the bacteria cells on IS electrodes have been studied using contact angle measurements.After immobilization of the bacteria, on the (Si/SiO₂/Si₃N₄) and (Si/SiO₂) substrates, the relationship between the evolution of the flat band potential ?V_FB and the urea concentration is found to be linear for values ranging from 10^? 2 M to 10^? 5 M.     

Three-Dimensional Network Polymeric Structure of (2-Amino-5 Ammoniopyridinium)[CuCl4]: Crystal Supramolecularity and Magnetic Properties

A single crystal structure determination of the complex (C₅H₉N₃)CuCl₄ [henceforth I] has been carried out. It crystallizes in the orthorhombic space group Cmca, with the cell parameters a=6.7053(5) Å, b=22.4171(19) Å, c=13.4173(9) Å, V=2016.8(3) Å³, and Z=8. In the complex, the anion is comprised of infinite zigzag chains of monochloro-bridged $\mathrm{CuCl}_{4}^{2-}$ units ?–CuCl₃–μ–Cl–CuCl₃–μ–Cl–CuCl₃–? surrounded by the pyridinium-ammonium cations. The Cu ions are five-coordinate to chloride ions in a distorted square-pyramidal geometry with the zigzag chains formed by corner-sharing polyhedra. The Cu ion is located 0.151 Å above the basal plane. In the crystal, there are four intermolecular hydrogen bonding interactions, linking the CuCl chains to the cations to form a 2D-network. The resulting 2D-networks are further linked by aryl?aryl (π?π) interactions within the cationic chains leading to a 3D-network. Variable temperature magnetic susceptibility data were fit to a one-dimensional S=1/2 antiferromagnetic chain model yielding C=0.44(1) emu-K/mol-Oe and J=?37(1) K.     

Progressive collapse of 2D reinforced concrete structures under sudden column removal

Once a column in building is removed due to gas explosion, vehicle impact, terrorist attack, earthquake or any natural disaster, the loading supported by removed column transfers to neighboring structural elements. If these elements are unable to resist the supplementary loading, they continue to fail, which leads to progressive collapse of building. In this paper, an efficient strategy to model and simulate the progressive collapse of multi-story reinforced concrete structure under sudden column removal is presented. The strategy is subdivided into several connected steps including failure mechanism creation, MBS dynamic analysis and dynamic contact simulation, the latter is solved by using conserving/decaying scheme to handle the stiff nonlinear dynamic equations. The effect of gravity loads, structure-ground contact, and structure-structure contact are accounted for as well. The main novelty in this study consists in the introduction of failure function, and the proper manner to control the mechanism creation of a frame until its total failure. Moreover, this contribution pertains to a very thorough investigation of progressive collapse of the structure under sudden column removal. The proposed methodology is applied to a six-story frame, and many different progressive collapse scenarios are investigated. The results illustrate the efficiency of the proposed strategy.     

Synergistic Effect between Fragaria ananassa and Cucurbita pepo L Leaf Extracts on Mild Steel Corrosion in Hydrochloric Acid Solutions

Protection of Metals and Physical Chemistry of Surfaces - The thermodynamic, inhibitive and synergistic properties of Fragaria ananassa (strawberry) and Cucurbita pepo L (zucchini) leaf extracts on...     

Towards the Development of Realistic DoS Dataset for Intelligent Transportation Systems

Wireless Personal Communications - Vehicular ad-hoc networks (VANETs) present security vulnerabilities, which make them prone to diverse cyberattacks. Denial of Service (DoS) is one of the most...     

Repair of the anophthalmic cavity of rats with synthetic hydroxyapatite

We placed spheres of synthetic hydroxyapatite (calcium chloride combined with sodium phosphate) in the eviscerated or enucleated orbital cavity of rats in order to evaluate the biocompatibility of this material with the orbital cavity. The study was conducted on 50 albino rats, 25 of which were submitted to enucleation and 25 to evisceration of one eye. The animals were sacrificed 7, 15, 21, 30 and 60 days after surgery and the orbital content was submitted to histopathological examination. A reaction of the young granulation tissue type was observed first. The hydroxyapatite was gradually surrounded by a granulomatous macrophage inflammatory response and covered with dense connective tissue that formed a sort of "mesh" septating and supporting progressively smaller blocks of the substance. The same type of reaction was observed in the enucleated and eviscerated cavities. We conclude that synthetic hydroxyapatite is an inert nonallergenic material which is appropriate for volume replacement in the anophthalmic cavity.     

Integration of Subjective and Objective Usability Evaluation Based on IEC/IEC 15939: A Case Study for Traffic Supervision Systems

Usability evaluation for interactive systems is one of the greatest interests for the Human–Computer Interaction community. To support this evaluation, several subjective and objective methods have been proposed and applied in academy and industry. In this context, usability evaluators usually work with a lot of and different kinds of data (e.g., ordinal values from questionnaires and performance rates) generated from different methods and tools and related to different usability criteria. In this article, we propose to integrate these data in a single way to better support the quality evaluators’ decision-making for traffic supervision systems domain. We apply the measurement information model defined by IEC/IEC 15939 with the use of indicators in an interactive system evaluation environment. Four indicators are presented from their specifications to their application in the evaluation of a system from a company. These indicators integrate evaluation results from usability questionnaires, an automated ergonomic guidelines inspector, and an electronic informer.     

Widgets Dedicated to User Interface Evaluation

In this article, evaluation-based widgets are proposed as a contribution to assist evaluators for early evaluation of user interfaces. This contribution imbricates the ergonomic quality evaluation process into widgets used for user-interface graphical composition. In other words, these widgets evaluate themselves according to a defined set of ergonomic guidelines. The proposed widgets indicate the possible interface design ergonomic inconsistencies as a notification to the designer. The guidelines set can be modified through an interface dedicated to guidelines definition into XML files. The proposed widgets are intended for the evaluation of different kind of user interfaces: WIMP, web, and mobile. An experimental evaluation, involving these evaluation-based widgets, is proposed to illustrate and to validate the approach.