Biotechnology-2014 biodegradation performance of phenol by free and alginate entrapped cells of Haloarcula strain D21, an extremely halophilic bacterium isolated from a solar saltern (Ain Salah, Algeria)

Immobilization is a general term that describes many different forms of cell attachment or entrapment. These different forms include encapsulation of cells in a polymer-gel and entrapment in a matrix. The Advantages of these techniques are to reduced possibility of inoculum contamination during storage, transport and application. So, beads are non toxic, biodegradable and non-polluting and can be produced in large quantities, stored for extended periods. Moreover, phenols and phenolic compounds are widely distributed as environmental pollutants due to their common presence in the effluents of many industrial processes, including oil refineries, ceramic plants, coal conversion process, phenolic resins, pharmaceutical and food Industries. The aim of this study was to compare the biodegradation performance of phenol by using free and encapsulated cells of Haloarcula strain D21 isolated from crude oil contaminated saline water collected at Ain Salah in Algeria. Batch experiments were carried out in order to obtain the maximum phenol degradation rates by analyzing the influence of the immobilization in calcium-alginate gel beads on biodegradation performanc

Prédiction des épitopes B de l'allergène Der p 5 et étude in silico de la structure et de l'état oligomérique des allergènes d'acariens des familles 5 et 21

140 p. ; ill. ; 30 cmCette recherche s'inscrit dans le cadre de l'étude in silico (en utilisant des approches bioinformatiques et de modélisations moléculaires) des structures 3D des allergènes d'acariens de poussières de maisons des familles 5 et 21. Nous avons pour objectifs de définir les épitopes de Der p 5 et de fournir des informations quant à leur propension à dimériser. Cela contribue à l'étude de leurs mécanismes d’allergénicité et pourrait aboutir à la conception de variants hypoallergéniques pour l'immunothérapie. Quatre régions antigéniques ont été identifiées pour Der p 5: H34-L39 (épitope-Nt), H58-D69 (épitope II), L92-E107 (épitope I) et K129-V132 (épitope-Ct) (selon la numérotation du code PDB 3MQ1 de Der p 5). Par la suite, les résidus situés dans ces régions qui pourraient jouer un rôle crucial dans la liaison aux immunoglobulines E (IgE) ont été sélectionnés selon des critères que nous avons définis (nature des acides aminés et leur accessibilité au solvant) pour la validation expérimentale. Par ailleurs, nous avons étudié la propension des allergènes Der f 5 et Der f 21 de Dermatophagoides farinae, Der p 21 de Dermatophagoides pteronyssinus, Sui 5 m de Suidasia medanensis et Lep d 5 de Lepidoglyphus destructor et Blo t 21 de Blomia tropicalis à dimériser et former une grande cavité hydrophobe similaire à celle de Der p 5. Cette cavité hydrophobe a été suggérée dans la littérature comme pouvant intervenir dans l'initiation du processus allergique en liant certains ligands hydrophobes. Nos résultats suggèrent que seulement Der f 5 pourrait former un dimère semblable à Der p 5. Les autres allergènes (Blo t 5, Sui 5 m, Lep d 5, Der p 21, 21 et Der f Blo t 21) ne présentent pas une telle propension. En outre, nous avons identifié des mutations qui devraient déstabiliser et/ou entraver la formation de la structure dimérique de Derp5, ce qui pourrait aider à la compréhension du rôle du processus de dimérisation dans la réponse allergique de ces allergène

The house dust mite allergen Der p 5 binds lipid ligands and stimulates airway epithelial cells through a TLR2‐dependent pathway

Background: Protein crystallographic studies suggest that the house dust mite (HDM) allergen Der p 5 potentially interacts with hydrophobic ligands. Der p 5, in association with its ligand(s), might therefore trigger innate immune signalling pathways in the airway epithelium and influence the initiation of the HDM‐allergic response. Objective: We investigated the lipid binding propensities of recombinant (r)Der p 5 and characterized the signalling pathways triggered by the allergen in airway epithelial cells. Methods: rDer p 5 was produced in Pichia pastoris and characterized by mass spectrometry, multi‐angle light scattering and circular dichroism. Its interactions with hydrophobic ligands were investigated in fluorescence‐based lipid binding assays and in‐silico docking simulations. Innate immune signalling pathways triggered by rDer p 5 were investigated in airway epithelial cell activation assays in vitro. Results: Biophysical analysis showed that rDer p 5 was monomeric and adopted a similar α‐helix‐rich fold at both physiological and acidic pH. Spectrofluorimetry experiments showed that rDer p 5 is able to selectively bind lipid ligands, but only under mild acidic pH conditions. Computer‐based docking simulations identified potential binding sites for these ligands. This allergen, with putatively associated lipid(s), triggered the production of IL‐8 in respiratory epithelial cells through a TLR2‐, NF‐kB‐ and MAPK‐dependent signalling pathway. Conclusions and Clinical Relevance: Despite the fact that Der p 5 represents a HDM allergen of intermediate prevalence, our findings regarding its lipid binding and activation of TLR2 indicate that it could participate in the initiation of the HDM‐allergic state

A comparative study of the effectiveness of vibration and acoustic emission in diagnosing a defective bearing in a planetry gearbox

Whilst vibration analysis of planetary gearbox faults is relatively well established, the application of Acoustic Emission (AE) to this field is still in its infancy. For planetary-type gearboxes it is more challenging to diagnose bearing faults due to the dynamically changing transmission paths which contribute to masking the vibration signature of interest. The present study is aimed to reduce the effect of background noise whilst extracting the fault feature from AE and vibration signatures. This has been achieved through developing of internal AE sensor for helicopter transmission system. In addition, series of signal processing procedure has been developed to improved detection of incipient damage. Three signal processing techniques including an adaptive filter, spectral kurtosis and envelope analysis, were applied to AE and vibration data acquired from a simplified planetary gearbox test rig with a seeded bearing defect. The results show that AE identified the defect earlier than vibration analysis irrespective of the tortuous transmission pat

Study of the effect of contact force model on the dynamic response of mechanical systems with dry clearance joints : computational and experimental approaches

The main objective of this work is to present a computational and experimental study on the contact forces developed in revolute clearance joints. For this purpose, a well-known slider-crank mechanism with a revolute clearance joint between the connecting rod and slider is utilized. The intra-joint contact forces that generated at this clearance joints are computed by considered several different elastic and dissipative approaches, namely those based on the Hertz contact theory and the ESDU tribology-based for cylindrical contacts, along with a hysteresis-type dissipative damping. The normal contact force is augmented with the dry Coulomb’s friction force. In addition, an experimental apparatus is use to obtained some experimental data in order to verify and validate the computational models. From the outcomes reported in this paper, it is concluded that the selection of the appropriate contact force model with proper dissipative damping plays a significant role in the dynamic response of mechanical systems involving contact events at low or moderate impact velocities.Fundação para a Ciência e a Tecnologia (FCT

Planetary bearing defect detection in a commercial helicopter main gearbox with vibration and acoustic emission

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Helicopter gearboxes significantly differ from other transmission types and exhibit unique behaviors that reduce the effectiveness of traditional fault diagnostics methods. In addition, due to lack of redundancy, helicopter transmission failure can lead to catastrophic accidents. Bearing faults in helicopter gearboxes are difficult to discriminate due to the low signal to noise ratio (SNR) in the presence of gear vibration. In addition, the vibration response from the planet gear bearings must be transmitted via a time-varying path through the ring gear to externally mounted accelerometers, which cause yet further bearing vibration signal suppression. This research programme has resulted in the successful proof of concept of a broadband wireless transmission sensor that incorporates power scavenging whilst operating within a helicopter gearbox. In addition, this paper investigates the application of signal separation techniques in detection of bearing faults within the epicyclic module of a large helicopter (CS-29) main gearbox using vibration and Acoustic Emissions (AE). It compares their effectiveness for various operating conditions. Three signal processing techniques including an adaptive filter, spectral kurtosis and envelope analysis, were combined for this investigation. In addition, this research discusses the feasibility of using AE for helicopter gearbox monitoring

A comprehensive survey of the analytical, numerical and experimental methodologies for dynamics of multibody mechanical systems with clearance or imperfect joints

"Available online 19 December 2017"A comprehensive survey of the literature of the most relevant analytical, numerical, and experimental approaches for the kinematic and dynamic analyses of multibody mechanical systems with clearance joints is presented in this review. Both dry and lubricated clearance joints are addressed here, and an effort is made to include a large number of research works in this particular field, which have been published since the 1960′s. First, the most frequently utilized methods for modeling planar and spatial multibody mechanical systems with clearance joints are analyzed, and compared. Other important phenomena commonly associated with clearance joint models, such as wear, non-smooth behavior, optimization and control, chaos, and uncertainty and links’ flexibility, are then discussed. The main assumptions procedures and conclusions for the different methodologies are also examined and compared. Finally, future developments and new applications of clearance joint modeling and analysis are highlighted.This research was supported in part by the China 111 Project (B16003) and the National Natural Science Foundation of China under Grants 11290151, 11472042 and 11221202. The work was also supported by the Portuguese Foundation for Science and Technology with the reference project UID/EEA/04436/2013, by FEDER funds through the COMPETE 2020 – Programa Operacional Competitividade e Internacionalização (POCI) with the reference project POCI-01-0145-FEDER-006941.info:eu-repo/semantics/publishedVersio

Untersuchungen zur Beseitigung oder Nutzung von Chlorkohlenwasserstoffen durch heterogen-katalysierte Gasphasenreaktionen

SIGLEAvailable from TIB Hannover: DW 6400 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Identification de deux archaebactéries halophiles strictes isolées à partir des eaux de gisement de quelques champs pétroliers du sud Algérien et contribution à la caractérisation des biomolécules produites

141 p. , ill. , 30 cmLes Bactéries halophiles extrêmes sont prédominantes dans le domaine des Archaea. Elles survivent dans les milieux à très forte concentration en sel (> 1.5M de NaCl). Actuellement, les Halobactéries présentent un grand intérêt grâce à leurs produits bioactives tel que les biosurfactants. Ces derniers ont des applications importantes grâce à leur propriété émulsifiante et activité tension active. Dans le présent travail, nous avons effectué des études microbiologiques, physiologiques et biochimiques des deux souches bactériennes halophiles A et D, leur pouvoir à produire des biopolymères à propriété émulsifiante, ainsi que l'essai de la caractérisation de ces biopolymères. D'après les résultats obtenus, la souche bactérienne A a été rapprochée au genre Halovivax et la souche bactrienne D au genre Haloarcula, au sien de la famille des Halobacteriacaea. Le biopolymère produit peut être un glycoprotéine pour la souche bactérienne A et d'un lipopeptide, glycolipide et /ou glycoprotéine pour la souche bactérienne